multi.c

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/*
 *  OpenVPN -- An application to securely tunnel IP networks
 *             over a single TCP/UDP port, with support for SSL/TLS-based
 *             session authentication and key exchange,
 *             packet encryption, packet authentication, and
 *             packet compression.
 *
 *  Copyright (C) 2002-2026 OpenVPN Inc <sales@openvpn.net>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2
 *  as published by the Free Software Foundation.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, see <https://www.gnu.org/licenses/>.
 */
 
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
 
#ifdef HAVE_SYS_INOTIFY_H
#include <sys/inotify.h>
#define INOTIFY_EVENT_BUFFER_SIZE 16384
#endif
 
#include "syshead.h"
 
#include "forward.h"
#include "multi.h"
#include "push.h"
#include "run_command.h"
#include "otime.h"
#include "gremlin.h"
#include "ssl_verify.h"
#include "ssl_ncp.h"
#include "vlan.h"
#include "auth_token.h"
#include "route.h"
#include <inttypes.h>
#include <string.h>
 
#include "memdbg.h"
 
 
#include "crypto_backend.h"
#include "ssl_util.h"
#include "dco.h"
#include "reflect_filter.h"
 
/*#define MULTI_DEBUG_EVENT_LOOP*/
 
#ifdef MULTI_DEBUG_EVENT_LOOP
static const char *
id(struct multi_instance *mi)
{
    if (mi)
    {
        return tls_common_name(mi->context.c2.tls_multi, false);
    }
    else
    {
        return "NULL";
    }
}
#endif
 
#ifdef ENABLE_MANAGEMENT
static void
set_cc_config(struct multi_instance *mi, struct buffer_list *cc_config)
{
    buffer_list_free(mi->cc_config);
    mi->cc_config = cc_config;
}
#endif
 
static bool
learn_address_script(const struct multi_context *m, const struct multi_instance *mi, const char *op,
                     const struct mroute_addr *addr)
{
    struct gc_arena gc = gc_new();
    struct env_set *es;
    bool ret = true;
    struct plugin_list *plugins;
 
    /* get environmental variable source */
    if (mi && mi->context.c2.es)
    {
        es = mi->context.c2.es;
    }
    else
    {
        es = env_set_create(&gc);
    }
 
    /* get plugin source */
    if (mi)
    {
        plugins = mi->context.plugins;
    }
    else
    {
        plugins = m->top.plugins;
    }
 
    if (plugin_defined(plugins, OPENVPN_PLUGIN_LEARN_ADDRESS))
    {
        struct argv argv = argv_new();
        argv_printf(&argv, "%s %s", op, mroute_addr_print(addr, &gc));
        if (mi)
        {
            argv_printf_cat(&argv, "%s", tls_common_name(mi->context.c2.tls_multi, false));
        }
        if (plugin_call(plugins, OPENVPN_PLUGIN_LEARN_ADDRESS, &argv, NULL, es)
            != OPENVPN_PLUGIN_FUNC_SUCCESS)
        {
            msg(M_WARN, "WARNING: learn-address plugin call failed");
            ret = false;
        }
        argv_free(&argv);
    }
 
    if (m->top.options.learn_address_script)
    {
        struct argv argv = argv_new();
        setenv_str(es, "script_type", "learn-address");
        argv_parse_cmd(&argv, m->top.options.learn_address_script);
        argv_printf_cat(&argv, "%s %s", op, mroute_addr_print(addr, &gc));
        if (mi)
        {
            argv_printf_cat(&argv, "%s", tls_common_name(mi->context.c2.tls_multi, false));
        }
        if (!openvpn_run_script(&argv, es, 0, "--learn-address"))
        {
            ret = false;
        }
        argv_free(&argv);
    }
 
    gc_free(&gc);
    return ret;
}
 
void
multi_ifconfig_pool_persist(struct multi_context *m, bool force)
{
    /* write pool data to file */
    if (m->ifconfig_pool && m->top.c1.ifconfig_pool_persist
        && (force || ifconfig_pool_write_trigger(m->top.c1.ifconfig_pool_persist)))
    {
        ifconfig_pool_write(m->top.c1.ifconfig_pool_persist, m->ifconfig_pool);
    }
}
 
static void
multi_reap_range(const struct multi_context *m, uint32_t start_bucket, uint32_t end_bucket)
{
    struct gc_arena gc = gc_new();
    struct hash_iterator hi;
    struct hash_element *he;
 
    dmsg(D_MULTI_DEBUG, "MULTI: REAP range %d -> %d", start_bucket, end_bucket);
    hash_iterator_init_range(m->vhash, &hi, start_bucket, end_bucket);
    while ((he = hash_iterator_next(&hi)) != NULL)
    {
        struct multi_route *r = (struct multi_route *)he->value;
        if (!multi_route_defined(m, r))
        {
            dmsg(D_MULTI_DEBUG, "MULTI: REAP DEL %s", mroute_addr_print(&r->addr, &gc));
            learn_address_script(m, NULL, "delete", &r->addr);
            multi_route_del(r);
            hash_iterator_delete_element(&hi);
        }
    }
    hash_iterator_free(&hi);
    gc_free(&gc);
}
 
static void
multi_reap_all(const struct multi_context *m)
{
    multi_reap_range(m, 0, hash_n_buckets(m->vhash));
}
 
static struct multi_reap *
multi_reap_new(uint32_t buckets_per_pass)
{
    struct multi_reap *mr;
    ALLOC_OBJ(mr, struct multi_reap);
    mr->bucket_base = 0;
    mr->buckets_per_pass = buckets_per_pass;
    mr->last_call = now;
    return mr;
}
 
void
multi_reap_process_dowork(const struct multi_context *m)
{
    struct multi_reap *mr = m->reaper;
    if (mr->bucket_base >= hash_n_buckets(m->vhash))
    {
        mr->bucket_base = 0;
    }
    multi_reap_range(m, mr->bucket_base, mr->bucket_base + mr->buckets_per_pass);
    mr->bucket_base += mr->buckets_per_pass;
    mr->last_call = now;
}
 
static void
multi_reap_free(struct multi_reap *mr)
{
    free(mr);
}
 
/*
 * How many buckets in vhash to reap per pass.
 */
static uint32_t
reap_buckets_per_pass(uint32_t n_buckets)
{
    return constrain_uint(n_buckets / REAP_DIVISOR, REAP_MIN, REAP_MAX);
}
 
#ifdef ENABLE_MANAGEMENT
 
static uint32_t
cid_hash_function(const void *key, uint32_t iv)
{
    const unsigned long *k = (const unsigned long *)key;
    return (uint32_t)*k;
}
 
static bool
cid_compare_function(const void *key1, const void *key2)
{
    const unsigned long *k1 = (const unsigned long *)key1;
    const unsigned long *k2 = (const unsigned long *)key2;
    return *k1 == *k2;
}
 
#endif
 
#ifdef ENABLE_ASYNC_PUSH
static uint32_t
/*
 * inotify watcher descriptors are used as hash value
 */
int_hash_function(const void *key, uint32_t iv)
{
    return (uint32_t)(uintptr_t)key;
}
 
static bool
int_compare_function(const void *key1, const void *key2)
{
    return (unsigned long)key1 == (unsigned long)key2;
}
#endif
 
/*
 * Main initialization function, init multi_context object.
 */
static void
multi_init(struct context *t)
{
    struct multi_context *m = t->multi;
    int dev = DEV_TYPE_UNDEF;
 
    msg(D_MULTI_LOW, "MULTI: multi_init called, r=%d v=%d", t->options.real_hash_size,
        t->options.virtual_hash_size);
 
    /*
     * Get tun/tap/null device type
     */
    dev = dev_type_enum(t->options.dev, t->options.dev_type);
 
    /*
     * Init our multi_context object.
     */
    CLEAR(*m);
 
    /*
     * Real address hash table (source port number is
     * considered to be part of the address).  Used
     * to determine which client sent an incoming packet
     * which is seen on the TCP/UDP socket.
     */
    m->hash = hash_init(t->options.real_hash_size, (uint32_t)get_random(),
                        mroute_addr_hash_function, mroute_addr_compare_function);
 
    /*
     * Virtual address hash table.  Used to determine
     * which client to route a packet to.
     */
    m->vhash = hash_init(t->options.virtual_hash_size, (uint32_t)get_random(),
                         mroute_addr_hash_function, mroute_addr_compare_function);
 
#ifdef ENABLE_MANAGEMENT
    m->cid_hash = hash_init(t->options.real_hash_size, 0, cid_hash_function, cid_compare_function);
#endif
 
#ifdef ENABLE_ASYNC_PUSH
    /*
     * Mapping between inotify watch descriptors and
     * multi_instances.
     */
    m->inotify_watchers = hash_init(t->options.real_hash_size, (uint32_t)get_random(),
                                    int_hash_function, int_compare_function);
#endif
 
    /*
     * This is our scheduler, for time-based wakeup
     * events.
     */
    m->schedule = schedule_init();
 
    /*
     * Limit frequency of incoming connections to control
     * DoS.
     */
    m->new_connection_limiter = frequency_limit_init(t->options.cf_max, t->options.cf_per);
    m->initial_rate_limiter =
        initial_rate_limit_init(t->options.cf_initial_max, t->options.cf_initial_per);
 
    /*
     * Allocate broadcast/multicast buffer list
     */
    m->mbuf = mbuf_init(t->options.n_bcast_buf);
 
    /*
     * Different status file format options are available
     */
    m->status_file_version = t->options.status_file_version;
 
    /*
     * Possibly allocate an ifconfig pool, do it
     * differently based on whether a tun or tap style
     * tunnel.
     */
    if (t->options.ifconfig_pool_defined || t->options.ifconfig_ipv6_pool_defined)
    {
        int pool_type = IFCONFIG_POOL_INDIV;
 
        if (dev == DEV_TYPE_TUN && t->options.topology == TOP_NET30)
        {
            pool_type = IFCONFIG_POOL_30NET;
        }
 
        m->ifconfig_pool = ifconfig_pool_init(
            t->options.ifconfig_pool_defined, pool_type, t->options.ifconfig_pool_start,
            t->options.ifconfig_pool_end, t->options.duplicate_cn,
            t->options.ifconfig_ipv6_pool_defined, t->options.ifconfig_ipv6_pool_base,
            t->options.ifconfig_ipv6_pool_netbits);
 
        /* reload pool data from file */
        if (t->c1.ifconfig_pool_persist)
        {
            ifconfig_pool_read(t->c1.ifconfig_pool_persist, m->ifconfig_pool);
        }
    }
 
    /*
     * Help us keep track of routing table.
     */
    m->route_helper = mroute_helper_init(MULTI_CACHE_ROUTE_TTL);
 
    /*
     * Initialize route and instance reaper.
     */
    m->reaper = multi_reap_new(reap_buckets_per_pass(t->options.virtual_hash_size));
 
    /*
     * Get local ifconfig address
     */
    CLEAR(m->local);
    ASSERT(t->c1.tuntap);
    mroute_extract_in_addr_t(&m->local, t->c1.tuntap->local);
 
    /*
     * Per-client limits
     */
    m->max_clients = t->options.max_clients;
 
    m->instances = calloc(m->max_clients, sizeof(struct multi_instance *));
 
    m->top.c2.event_set = t->c2.event_set;
 
    /*
     * Initialize multi-socket I/O wait object
     */
    m->multi_io = multi_io_init(m->max_clients);
    m->tcp_queue_limit = t->options.tcp_queue_limit;
 
    /*
     * Allow client <-> client communication, without going through
     * tun/tap interface and network stack?
     */
    m->enable_c2c = t->options.enable_c2c;
 
    /* initialize stale routes check timer */
    if (t->options.stale_routes_check_interval > 0)
    {
        msg(M_INFO,
            "Initializing stale route check timer to run every %i seconds and to removing routes with activity timeout older than %i seconds",
            t->options.stale_routes_check_interval, t->options.stale_routes_ageing_time);
        event_timeout_init(&m->stale_routes_check_et, t->options.stale_routes_check_interval, 0);
    }
 
    m->deferred_shutdown_signal.signal_received = 0;
}
 
const char *
multi_instance_string(const struct multi_instance *mi, bool null, struct gc_arena *gc)
{
    if (mi)
    {
        struct buffer out = alloc_buf_gc(MULTI_PREFIX_MAX_LENGTH, gc);
        const char *cn = tls_common_name(mi->context.c2.tls_multi, true);
 
        if (cn)
        {
            buf_printf(&out, "%s/", cn);
        }
        buf_printf(&out, "%s", mroute_addr_print(&mi->real, gc));
        if (mi->context.c2.tls_multi && check_debug_level(D_DCO_DEBUG)
            && dco_enabled(&mi->context.options))
        {
            buf_printf(&out, " peer-id=%d", mi->context.c2.tls_multi->peer_id);
        }
        return BSTR(&out);
    }
    else if (null)
    {
        return NULL;
    }
    else
    {
        return "UNDEF";
    }
}
 
static void
generate_prefix(struct multi_instance *mi)
{
    struct gc_arena gc = gc_new();
    const char *prefix = multi_instance_string(mi, true, &gc);
    if (prefix)
    {
        strncpynt(mi->msg_prefix, prefix, sizeof(mi->msg_prefix));
    }
    else
    {
        mi->msg_prefix[0] = '\0';
    }
    set_prefix(mi);
    gc_free(&gc);
}
 
void
ungenerate_prefix(struct multi_instance *mi)
{
    mi->msg_prefix[0] = '\0';
    set_prefix(mi);
}
 
/*
 * Tell the route helper about deleted iroutes so
 * that it can update its mask of currently used
 * CIDR netlengths.
 */
static void
multi_del_iroutes(struct multi_context *m, struct multi_instance *mi)
{
    const struct iroute *ir;
    const struct iroute_ipv6 *ir6;
 
    dco_delete_iroutes(m, mi);
 
    if (TUNNEL_TYPE(mi->context.c1.tuntap) == DEV_TYPE_TUN)
    {
        for (ir = mi->context.options.iroutes; ir != NULL; ir = ir->next)
        {
            mroute_helper_del_iroute46(m->route_helper, ir->netbits);
        }
 
        for (ir6 = mi->context.options.iroutes_ipv6; ir6 != NULL; ir6 = ir6->next)
        {
            mroute_helper_del_iroute46(m->route_helper, ir6->netbits);
        }
    }
}
 
static void
setenv_stats(struct multi_context *m, struct context *c)
{
    if (dco_enabled(&m->top.options))
    {
        if (dco_get_peer_stats_multi(&m->top.c1.tuntap->dco, false) < 0)
        {
            return;
        }
    }
 
    setenv_counter(c->c2.es, "bytes_received", c->c2.link_read_bytes + c->c2.dco_read_bytes);
    setenv_counter(c->c2.es, "bytes_sent", c->c2.link_write_bytes + c->c2.dco_write_bytes);
}
 
static void
multi_client_disconnect_setenv(struct multi_context *m, struct multi_instance *mi)
{
    /* setenv client real IP address */
    setenv_trusted(mi->context.c2.es, get_link_socket_info(&mi->context));
 
    /* setenv stats */
    setenv_stats(m, &mi->context);
 
    /* setenv connection duration */
    setenv_long_long(mi->context.c2.es, "time_duration", now - mi->created);
}
 
static void
multi_client_disconnect_script(struct multi_context *m, struct multi_instance *mi)
{
    multi_client_disconnect_setenv(m, mi);
 
    if (plugin_defined(mi->context.plugins, OPENVPN_PLUGIN_CLIENT_DISCONNECT))
    {
        if (plugin_call(mi->context.plugins, OPENVPN_PLUGIN_CLIENT_DISCONNECT, NULL, NULL,
                        mi->context.c2.es)
            != OPENVPN_PLUGIN_FUNC_SUCCESS)
        {
            msg(M_WARN, "WARNING: client-disconnect plugin call failed");
        }
    }
 
    if (mi->context.options.client_disconnect_script)
    {
        struct argv argv = argv_new();
        setenv_str(mi->context.c2.es, "script_type", "client-disconnect");
        argv_parse_cmd(&argv, mi->context.options.client_disconnect_script);
        openvpn_run_script(&argv, mi->context.c2.es, 0, "--client-disconnect");
        argv_free(&argv);
    }
#ifdef ENABLE_MANAGEMENT
    if (management)
    {
        management_notify_client_close(management, &mi->context.c2.mda_context, mi->context.c2.es);
    }
#endif
}
 
void
multi_close_instance(struct multi_context *m, struct multi_instance *mi, bool shutdown)
{
    ASSERT(!mi->halt);
    mi->halt = true;
    bool is_dgram = proto_is_dgram(mi->context.c2.link_sockets[0]->info.proto);
 
    dmsg(D_MULTI_DEBUG, "MULTI: multi_close_instance called");
 
    /* adjust current client connection count */
    m->n_clients += mi->n_clients_delta;
    mi->n_clients_delta = 0;
 
    /* prevent dangling pointers */
    if (m->pending == mi)
    {
        multi_set_pending(m, NULL);
    }
    if (m->earliest_wakeup == mi)
    {
        m->earliest_wakeup = NULL;
    }
 
    if (!shutdown)
    {
        if (mi->did_real_hash)
        {
            ASSERT(hash_remove(m->hash, &mi->real));
        }
#ifdef ENABLE_MANAGEMENT
        if (mi->did_cid_hash)
        {
            ASSERT(hash_remove(m->cid_hash, &mi->context.c2.mda_context.cid));
        }
#endif
 
#ifdef ENABLE_ASYNC_PUSH
        if (mi->inotify_watch != -1)
        {
            hash_remove(m->inotify_watchers, (void *)(uintptr_t)mi->inotify_watch);
            mi->inotify_watch = -1;
        }
#endif
 
        if (mi->context.c2.tls_multi->peer_id != MAX_PEER_ID)
        {
            m->instances[mi->context.c2.tls_multi->peer_id] = NULL;
 
            /* Adjust the max_peerid as this might have been the highest
             * peer id instance */
            while (m->max_peerid > 0 && m->instances[m->max_peerid] == NULL)
            {
                m->max_peerid--;
            }
        }
 
        schedule_remove_entry(m->schedule, (struct schedule_entry *)mi);
 
        ifconfig_pool_release(m->ifconfig_pool, mi->vaddr_handle, false);
 
        if (mi->did_iroutes)
        {
            multi_del_iroutes(m, mi);
            mi->did_iroutes = false;
        }
 
        if (!is_dgram)
        {
            multi_tcp_dereference_instance(m->multi_io, mi);
        }
 
        mbuf_dereference_instance(m->mbuf, mi);
    }
 
#ifdef ENABLE_MANAGEMENT
    set_cc_config(mi, NULL);
#endif
 
    if (mi->context.c2.tls_multi->multi_state >= CAS_CONNECT_DONE)
    {
        multi_client_disconnect_script(m, mi);
    }
 
    close_context(&mi->context, SIGTERM, CC_GC_FREE);
 
    multi_tcp_instance_specific_free(mi);
 
    ungenerate_prefix(mi);
 
    /*
     * Don't actually delete the instance memory allocation yet,
     * because virtual routes may still point to it.  Let the
     * vhash reaper deal with it.
     */
    multi_instance_dec_refcount(mi);
}
 
/*
 * Called on shutdown or restart.
 */
static void
multi_uninit(struct multi_context *m)
{
    if (m->hash)
    {
        for (uint32_t i = 0; i <= m->max_peerid; i++)
        {
            struct multi_instance *mi = m->instances[i];
            if (mi)
            {
                multi_close_instance(m, mi, true);
            }
        }
 
        multi_reap_all(m);
 
        hash_free(m->hash);
        hash_free(m->vhash);
#ifdef ENABLE_MANAGEMENT
        hash_free(m->cid_hash);
#endif
        m->hash = NULL;
 
        free(m->instances);
 
#ifdef ENABLE_ASYNC_PUSH
        hash_free(m->inotify_watchers);
        m->inotify_watchers = NULL;
#endif
 
        schedule_free(m->schedule);
        mbuf_free(m->mbuf);
        ifconfig_pool_free(m->ifconfig_pool);
        frequency_limit_free(m->new_connection_limiter);
        initial_rate_limit_free(m->initial_rate_limiter);
        multi_reap_free(m->reaper);
        mroute_helper_free(m->route_helper);
        multi_io_free(m->multi_io);
    }
}
 
/*
 * Create a client instance object for a newly connected client.
 */
struct multi_instance *
multi_create_instance(struct multi_context *m, const struct mroute_addr *real,
                      struct link_socket *sock)
{
    struct gc_arena gc = gc_new();
    struct multi_instance *mi;
 
    msg(D_MULTI_MEDIUM, "MULTI: multi_create_instance called");
 
    ALLOC_OBJ_CLEAR(mi, struct multi_instance);
 
    mi->gc = gc_new();
    multi_instance_inc_refcount(mi);
    mi->vaddr_handle = -1;
    mi->created = now;
    mroute_addr_init(&mi->real);
 
    if (real)
    {
        mi->real = *real;
        generate_prefix(mi);
    }
 
    inherit_context_child(&mi->context, &m->top, sock);
    if (IS_SIG(&mi->context))
    {
        goto err;
    }
 
    mi->context.c2.tls_multi->multi_state = CAS_NOT_CONNECTED;
 
    if (hash_n_elements(m->hash) >= m->max_clients)
    {
        msg(D_MULTI_ERRORS,
            "MULTI: new incoming connection would exceed maximum number of clients (%d)",
            m->max_clients);
        goto err;
    }
 
    if (!real) /* TCP mode? */
    {
        if (!multi_tcp_instance_specific_init(m, mi))
        {
            goto err;
        }
        generate_prefix(mi);
    }
 
#ifdef ENABLE_MANAGEMENT
    do
    {
        mi->context.c2.mda_context.cid = m->cid_counter++;
    } while (!hash_add(m->cid_hash, &mi->context.c2.mda_context.cid, mi, false));
    mi->did_cid_hash = true;
#endif
 
    mi->context.c2.push_request_received = false;
#ifdef ENABLE_ASYNC_PUSH
    mi->inotify_watch = -1;
#endif
 
    if (!multi_process_post(m, mi, MPP_PRE_SELECT))
    {
        msg(D_MULTI_ERRORS, "MULTI: signal occurred during client instance initialization");
        goto err;
    }
 
    mi->ev_arg.type = EVENT_ARG_MULTI_INSTANCE;
    mi->ev_arg.u.mi = mi;
 
    gc_free(&gc);
    return mi;
 
err:
    multi_close_instance(m, mi, false);
    gc_free(&gc);
    return NULL;
}
 
/*
 * Dump tables -- triggered by SIGUSR2.
 * If status file is defined, write to file.
 * If status file is NULL, write to syslog.
 */
static void
multi_print_status(struct multi_context *m, struct status_output *so, const int version)
{
    if (m->hash)
    {
        struct gc_arena gc_top = gc_new();
        struct hash_iterator hi;
        const struct hash_element *he;
 
        status_reset(so);
 
        if (dco_enabled(&m->top.options))
        {
            if (dco_get_peer_stats_multi(&m->top.c1.tuntap->dco, true) < 0)
            {
                return;
            }
        }
 
        if (version == 1)
        {
            /*
             * Status file version 1
             */
            status_printf(so, "OpenVPN CLIENT LIST");
            status_printf(so, "Updated,%s", time_string(0, 0, false, &gc_top));
            status_printf(so, "Common Name,Real Address,Bytes Received,Bytes Sent,Connected Since");
            hash_iterator_init(m->hash, &hi);
            while ((he = hash_iterator_next(&hi)))
            {
                struct gc_arena gc = gc_new();
                const struct multi_instance *mi = (struct multi_instance *)he->value;
 
                if (!mi->halt)
                {
                    status_printf(so, "%s,%s," counter_format "," counter_format ",%s",
                                  tls_common_name(mi->context.c2.tls_multi, false),
                                  mroute_addr_print(&mi->real, &gc),
                                  mi->context.c2.link_read_bytes + mi->context.c2.dco_read_bytes,
                                  mi->context.c2.link_write_bytes + mi->context.c2.dco_write_bytes,
                                  time_string(mi->created, 0, false, &gc));
                }
                gc_free(&gc);
            }
            hash_iterator_free(&hi);
 
            status_printf(so, "ROUTING TABLE");
            status_printf(so, "Virtual Address,Common Name,Real Address,Last Ref");
            hash_iterator_init(m->vhash, &hi);
            while ((he = hash_iterator_next(&hi)))
            {
                struct gc_arena gc = gc_new();
                const struct multi_route *route = (struct multi_route *)he->value;
 
                if (multi_route_defined(m, route))
                {
                    const struct multi_instance *mi = route->instance;
                    const struct mroute_addr *ma = &route->addr;
                    char flags[2] = { 0, 0 };
 
                    if (route->flags & MULTI_ROUTE_CACHE)
                    {
                        flags[0] = 'C';
                    }
                    status_printf(so, "%s%s,%s,%s,%s", mroute_addr_print(ma, &gc), flags,
                                  tls_common_name(mi->context.c2.tls_multi, false),
                                  mroute_addr_print(&mi->real, &gc),
                                  time_string(route->last_reference, 0, false, &gc));
                }
                gc_free(&gc);
            }
            hash_iterator_free(&hi);
 
            status_printf(so, "GLOBAL STATS");
            if (m->mbuf)
            {
                status_printf(so, "Max bcast/mcast queue length,%d", mbuf_maximum_queued(m->mbuf));
            }
 
            status_printf(so, "END");
        }
        else if (version == 2 || version == 3)
        {
            const char sep = (version == 3) ? '\t' : ',';
 
            /*
             * Status file version 2 and 3
             */
            status_printf(so, "TITLE%c%s", sep, title_string);
            status_printf(so, "TIME%c%s%c%u", sep, time_string(now, 0, false, &gc_top), sep,
                          (unsigned int)now);
            status_printf(
                so,
                "HEADER%cCLIENT_LIST%cCommon Name%cReal Address%cVirtual Address%cVirtual IPv6 Address%cBytes Received%cBytes Sent%cConnected Since%cConnected Since (time_t)%cUsername%cClient ID%cPeer ID%cData Channel Cipher",
                sep, sep, sep, sep, sep, sep, sep, sep, sep, sep, sep, sep, sep);
            hash_iterator_init(m->hash, &hi);
            while ((he = hash_iterator_next(&hi)))
            {
                struct gc_arena gc = gc_new();
                const struct multi_instance *mi = (struct multi_instance *)he->value;
 
                if (!mi->halt)
                {
                    status_printf(
                        so,
                        "CLIENT_LIST%c%s%c%s%c%s%c%s%c" counter_format "%c" counter_format
                        "%c%s%c%u%c%s%c"
#ifdef ENABLE_MANAGEMENT
                        "%lu"
#else
                        ""
#endif
                        "%c%" PRIu32 "%c%s",
                        sep, tls_common_name(mi->context.c2.tls_multi, false), sep,
                        mroute_addr_print(&mi->real, &gc), sep,
                        print_in_addr_t(mi->reporting_addr, IA_EMPTY_IF_UNDEF, &gc), sep,
                        print_in6_addr(mi->reporting_addr_ipv6, IA_EMPTY_IF_UNDEF, &gc), sep,
                        mi->context.c2.link_read_bytes + mi->context.c2.dco_read_bytes, sep,
                        mi->context.c2.link_write_bytes + mi->context.c2.dco_write_bytes, sep,
                        time_string(mi->created, 0, false, &gc), sep, (unsigned int)mi->created,
                        sep, tls_username(mi->context.c2.tls_multi, false),
#ifdef ENABLE_MANAGEMENT
                        sep, mi->context.c2.mda_context.cid,
#else
                        sep,
#endif
                        sep,
                        mi->context.c2.tls_multi ? mi->context.c2.tls_multi->peer_id : UINT32_MAX,
                        sep, translate_cipher_name_to_openvpn(mi->context.options.ciphername));
                }
                gc_free(&gc);
            }
            hash_iterator_free(&hi);
 
            status_printf(
                so,
                "HEADER%cROUTING_TABLE%cVirtual Address%cCommon Name%cReal Address%cLast Ref%cLast Ref (time_t)",
                sep, sep, sep, sep, sep, sep);
            hash_iterator_init(m->vhash, &hi);
            while ((he = hash_iterator_next(&hi)))
            {
                struct gc_arena gc = gc_new();
                const struct multi_route *route = (struct multi_route *)he->value;
 
                if (multi_route_defined(m, route))
                {
                    const struct multi_instance *mi = route->instance;
                    const struct mroute_addr *ma = &route->addr;
                    char flags[2] = { 0, 0 };
 
                    if (route->flags & MULTI_ROUTE_CACHE)
                    {
                        flags[0] = 'C';
                    }
                    status_printf(so, "ROUTING_TABLE%c%s%s%c%s%c%s%c%s%c%u", sep,
                                  mroute_addr_print(ma, &gc), flags, sep,
                                  tls_common_name(mi->context.c2.tls_multi, false), sep,
                                  mroute_addr_print(&mi->real, &gc), sep,
                                  time_string(route->last_reference, 0, false, &gc), sep,
                                  (unsigned int)route->last_reference);
                }
                gc_free(&gc);
            }
            hash_iterator_free(&hi);
 
            if (m->mbuf)
            {
                status_printf(so, "GLOBAL_STATS%cMax bcast/mcast queue length%c%d", sep, sep,
                              mbuf_maximum_queued(m->mbuf));
            }
 
            status_printf(so, "GLOBAL_STATS%cdco_enabled%c%d", sep, sep,
                          dco_enabled(&m->top.options));
            status_printf(so, "END");
        }
        else
        {
            status_printf(so, "ERROR: bad status format version number");
        }
 
#ifdef PACKET_TRUNCATION_CHECK
        {
            status_printf(so, "HEADER,ERRORS,Common Name,TUN Read Trunc,TUN Write Trunc,Pre-encrypt Trunc,Post-decrypt Trunc");
            hash_iterator_init(m->hash, &hi);
            while ((he = hash_iterator_next(&hi)))
            {
                struct gc_arena gc = gc_new();
                const struct multi_instance *mi = (struct multi_instance *)he->value;
 
                if (!mi->halt)
                {
                    status_printf(so,
                                  "ERRORS,%s," counter_format "," counter_format "," counter_format
                                  "," counter_format,
                                  tls_common_name(mi->context.c2.tls_multi, false),
                                  m->top.c2.n_trunc_tun_read, mi->context.c2.n_trunc_tun_write,
                                  mi->context.c2.n_trunc_pre_encrypt,
                                  mi->context.c2.n_trunc_post_decrypt);
                }
                gc_free(&gc);
            }
            hash_iterator_free(&hi);
        }
#endif /* ifdef PACKET_TRUNCATION_CHECK */
 
        status_flush(so);
        gc_free(&gc_top);
    }
 
#ifdef ENABLE_ASYNC_PUSH
    if (m->inotify_watchers)
    {
        msg(D_MULTI_DEBUG, "inotify watchers count: %d", hash_n_elements(m->inotify_watchers));
    }
#endif
}
 
/*
 * Learn a virtual address or route.
 * The learn will fail if the learn address
 * script/plugin fails.  In this case the
 * return value may be != mi.
 * Return the instance which owns this route,
 * or NULL if none.
 */
static struct multi_instance *
multi_learn_addr(struct multi_context *m, struct multi_instance *mi, const struct mroute_addr *addr,
                 const unsigned int flags)
{
    struct hash_element *he;
    const uint32_t hv = hash_value(m->vhash, addr);
    struct hash_bucket *bucket = hash_bucket(m->vhash, hv);
    struct multi_route *oldroute = NULL;
    struct multi_instance *owner = NULL;
    struct gc_arena gc = gc_new();
 
    /* if route currently exists, get the instance which owns it */
    he = hash_lookup_fast(m->vhash, bucket, addr, hv);
    if (he)
    {
        oldroute = (struct multi_route *)he->value;
    }
    if (oldroute && multi_route_defined(m, oldroute))
    {
        owner = oldroute->instance;
    }
 
    /* do we need to add address to hash table? */
    if ((!owner || owner != mi) && mroute_learnable_address(addr, &gc)
        && !mroute_addr_equal(addr, &m->local))
    {
        struct multi_route *newroute;
        bool learn_succeeded = false;
 
        ALLOC_OBJ(newroute, struct multi_route);
        newroute->addr = *addr;
        newroute->instance = mi;
        newroute->flags = flags;
        newroute->last_reference = now;
        newroute->cache_generation = 0;
 
        /* The cache is invalidated when cache_generation is incremented */
        if (flags & MULTI_ROUTE_CACHE)
        {
            newroute->cache_generation = m->route_helper->cache_generation;
        }
 
        if (oldroute) /* route already exists? */
        {
            if (route_quota_test(mi) && learn_address_script(m, mi, "update", &newroute->addr))
            {
                learn_succeeded = true;
                owner = mi;
                multi_instance_inc_refcount(mi);
                route_quota_inc(mi);
 
                /* delete old route */
                multi_route_del(oldroute);
 
                /* modify hash table entry, replacing old route */
                he->key = &newroute->addr;
                he->value = newroute;
            }
        }
        else
        {
            if (route_quota_test(mi) && learn_address_script(m, mi, "add", &newroute->addr))
            {
                learn_succeeded = true;
                owner = mi;
                multi_instance_inc_refcount(mi);
                route_quota_inc(mi);
 
                /* add new route */
                hash_add_fast(m->vhash, bucket, &newroute->addr, hv, newroute);
            }
        }
 
        msg(D_MULTI_LOW, "MULTI: Learn%s: %s -> %s", learn_succeeded ? "" : " FAILED",
            mroute_addr_print(&newroute->addr, &gc), multi_instance_string(mi, false, &gc));
 
        if (!learn_succeeded)
        {
            free(newroute);
        }
    }
    gc_free(&gc);
 
    return owner;
}
 
/*
 * Get client instance based on virtual address.
 */
static struct multi_instance *
multi_get_instance_by_virtual_addr(struct multi_context *m, const struct mroute_addr *addr,
                                   bool cidr_routing)
{
    struct multi_route *route;
    struct multi_instance *ret = NULL;
 
    /* check for local address */
    if (mroute_addr_equal(addr, &m->local))
    {
        return NULL;
    }
 
    route = (struct multi_route *)hash_lookup(m->vhash, addr);
 
    /* does host route (possible cached) exist? */
    if (route && multi_route_defined(m, route))
    {
        struct multi_instance *mi = route->instance;
        route->last_reference = now;
        ret = mi;
    }
    else if (cidr_routing) /* do we need to regenerate a host route cache entry? */
    {
        struct mroute_helper *rh = m->route_helper;
        struct mroute_addr tryaddr;
        int i;
 
        /* cycle through each CIDR length */
        for (i = 0; i < rh->n_net_len; ++i)
        {
            tryaddr = *addr;
            tryaddr.type |= MR_WITH_NETBITS;
            tryaddr.netbits = rh->net_len[i];
            mroute_addr_mask_host_bits(&tryaddr);
 
            /* look up a possible route with netbits netmask */
            route = (struct multi_route *)hash_lookup(m->vhash, &tryaddr);
 
            if (route && multi_route_defined(m, route))
            {
                /* found an applicable route, cache host route */
                struct multi_instance *mi = route->instance;
                multi_learn_addr(m, mi, addr, MULTI_ROUTE_CACHE | MULTI_ROUTE_AGEABLE);
                ret = mi;
                break;
            }
        }
    }
 
#ifdef ENABLE_DEBUG
    if (check_debug_level(D_MULTI_DEBUG))
    {
        struct gc_arena gc = gc_new();
        const char *addr_text = mroute_addr_print(addr, &gc);
        if (ret)
        {
            dmsg(D_MULTI_DEBUG, "GET INST BY VIRT: %s -> %s via %s", addr_text,
                 multi_instance_string(ret, false, &gc), mroute_addr_print(&route->addr, &gc));
        }
        else
        {
            dmsg(D_MULTI_DEBUG, "GET INST BY VIRT: %s [failed]", addr_text);
        }
        gc_free(&gc);
    }
#endif
 
    ASSERT(!(ret && ret->halt));
    return ret;
}
 
/*
 * Helper function to multi_learn_addr().
 */
static struct multi_instance *
multi_learn_in_addr_t(struct multi_context *m, struct multi_instance *mi, in_addr_t a,
                      int netbits, /* -1 if host route, otherwise # of network bits in address */
                      bool primary)
{
    struct openvpn_sockaddr remote_si;
    struct mroute_addr addr = { 0 };
 
    CLEAR(remote_si);
    remote_si.addr.in4.sin_family = AF_INET;
    remote_si.addr.in4.sin_addr.s_addr = htonl(a);
    addr.proto = 0;
    ASSERT(mroute_extract_openvpn_sockaddr(&addr, &remote_si, false));
 
    if (netbits >= 0)
    {
        addr.type |= MR_WITH_NETBITS;
        addr.netbits = (uint8_t)netbits;
    }
 
    struct multi_instance *owner = multi_learn_addr(m, mi, &addr, 0);
#ifdef ENABLE_MANAGEMENT
    if (management && owner)
    {
        management_learn_addr(management, &mi->context.c2.mda_context, &addr, primary);
    }
#endif
    if (primary && multi_check_push_ifconfig_extra_route(mi, addr.v4.addr))
    {
        /* "primary" is the VPN ifconfig address of the peer */
        /* if it does not fall into the network defined by ifconfig_local
         * we install this as extra onscope address on the interface  */
        addr.netbits = 32;
        addr.type |= MR_ONLINK_DCO_ADDR;
 
        dco_install_iroute(m, mi, &addr);
    }
    else if (!primary)
    {
        ASSERT(netbits >= 0); /* DCO requires populated netbits */
        dco_install_iroute(m, mi, &addr);
    }
 
    return owner;
}
 
static struct multi_instance *
multi_learn_in6_addr(struct multi_context *m, struct multi_instance *mi, struct in6_addr a6,
                     int netbits, /* -1 if host route, otherwise # of network bits in address */
                     bool primary)
{
    struct mroute_addr addr = { 0 };
 
    addr.len = 16;
    addr.type = MR_ADDR_IPV6;
    addr.netbits = 0;
    addr.v6.addr = a6;
 
    if (netbits >= 0)
    {
        addr.type |= MR_WITH_NETBITS;
        addr.netbits = (uint8_t)netbits;
        mroute_addr_mask_host_bits(&addr);
    }
 
    struct multi_instance *owner = multi_learn_addr(m, mi, &addr, 0);
#ifdef ENABLE_MANAGEMENT
    if (management && owner)
    {
        management_learn_addr(management, &mi->context.c2.mda_context, &addr, primary);
    }
#endif
    if (primary && multi_check_push_ifconfig_ipv6_extra_route(mi, &addr.v6.addr))
    {
        /* "primary" is the VPN ifconfig address of the peer */
        /* if it does not fall into the network defined by ifconfig_local
         * we install this as extra onscope address on the interface  */
        addr.netbits = 128;
        addr.type |= MR_ONLINK_DCO_ADDR;
 
        dco_install_iroute(m, mi, &addr);
    }
    else if (!primary)
    {
        /* "primary" is the VPN ifconfig address of the peer and already
         * known to DCO, so only install "extra" iroutes (primary = false)
         */
        ASSERT(netbits >= 0); /* DCO requires populated netbits */
        dco_install_iroute(m, mi, &addr);
    }
 
    return owner;
}
 
/*
 * A new client has connected, add routes (server -> client)
 * to internal routing table.
 */
static void
multi_add_iroutes(struct multi_context *m, struct multi_instance *mi)
{
    struct gc_arena gc = gc_new();
    const struct iroute *ir;
    const struct iroute_ipv6 *ir6;
    if (TUNNEL_TYPE(mi->context.c1.tuntap) == DEV_TYPE_TUN)
    {
        mi->did_iroutes = true;
        for (ir = mi->context.options.iroutes; ir != NULL; ir = ir->next)
        {
            if (ir->netbits >= 0)
            {
                msg(D_MULTI_LOW, "MULTI: internal route %s/%d -> %s",
                    print_in_addr_t(ir->network, 0, &gc), ir->netbits,
                    multi_instance_string(mi, false, &gc));
            }
            else
            {
                msg(D_MULTI_LOW, "MULTI: internal route %s -> %s",
                    print_in_addr_t(ir->network, 0, &gc), multi_instance_string(mi, false, &gc));
            }
 
            mroute_helper_add_iroute46(m->route_helper, ir->netbits);
 
            multi_learn_in_addr_t(m, mi, ir->network, ir->netbits, false);
        }
        for (ir6 = mi->context.options.iroutes_ipv6; ir6 != NULL; ir6 = ir6->next)
        {
            msg(D_MULTI_LOW, "MULTI: internal route %s/%d -> %s",
                print_in6_addr(ir6->network, 0, &gc), ir6->netbits,
                multi_instance_string(mi, false, &gc));
 
            mroute_helper_add_iroute46(m->route_helper, ir6->netbits);
 
            multi_learn_in6_addr(m, mi, ir6->network, ir6->netbits, false);
        }
    }
    gc_free(&gc);
}
 
/*
 * Given an instance (new_mi), delete all other instances which use the
 * same common name.
 */
static void
multi_delete_dup(struct multi_context *m, struct multi_instance *new_mi)
{
    if (new_mi)
    {
        const char *new_cn = tls_common_name(new_mi->context.c2.tls_multi, true);
        if (new_cn)
        {
            int count = 0;
 
            for (uint32_t i = 0; i <= m->max_peerid; i++)
            {
                struct multi_instance *mi = m->instances[i];
                if (mi && mi != new_mi && !mi->halt)
                {
                    const char *cn = tls_common_name(mi->context.c2.tls_multi, true);
                    if (cn && !strcmp(cn, new_cn))
                    {
                        multi_close_instance(m, mi, false);
                        ++count;
                    }
                }
            }
 
            if (count)
            {
                msg(D_MULTI_LOW,
                    "MULTI: new connection by client '%s' will cause previous active sessions by this client to be dropped.  Remember to use the --duplicate-cn option if you want multiple clients using the same certificate or username to concurrently connect.",
                    new_cn);
            }
        }
    }
}
 
static void
check_stale_routes(struct multi_context *m)
{
    struct gc_arena gc = gc_new();
    struct hash_iterator hi;
    struct hash_element *he;
 
    dmsg(D_MULTI_DEBUG, "MULTI: Checking stale routes");
    hash_iterator_init_range(m->vhash, &hi, 0, hash_n_buckets(m->vhash));
    while ((he = hash_iterator_next(&hi)) != NULL)
    {
        struct multi_route *r = (struct multi_route *)he->value;
        if (multi_route_defined(m, r)
            && difftime(now, r->last_reference) >= m->top.options.stale_routes_ageing_time)
        {
            dmsg(D_MULTI_DEBUG, "MULTI: Deleting stale route for address '%s'",
                 mroute_addr_print(&r->addr, &gc));
            learn_address_script(m, NULL, "delete", &r->addr);
            multi_route_del(r);
            hash_iterator_delete_element(&hi);
        }
    }
    hash_iterator_free(&hi);
    gc_free(&gc);
}
 
/*
 * Ensure that endpoint to be pushed to client
 * complies with --ifconfig-push-constraint directive.
 */
static bool
ifconfig_push_constraint_satisfied(const struct context *c)
{
    const struct options *o = &c->options;
    if (o->push_ifconfig_constraint_defined && c->c2.push_ifconfig_defined)
    {
        return (o->push_ifconfig_constraint_netmask & c->c2.push_ifconfig_local)
               == o->push_ifconfig_constraint_network;
    }
    else
    {
        return true;
    }
}
 
/*
 * Select a virtual address for a new client instance.
 * Use an --ifconfig-push directive, if given (static IP).
 * Otherwise use an --ifconfig-pool address (dynamic IP).
 */
static void
multi_select_virtual_addr(struct multi_context *m, struct multi_instance *mi)
{
    struct gc_arena gc = gc_new();
 
    /*
     * If ifconfig addresses were set by dynamic config file,
     * release pool addresses, otherwise keep them.
     */
    if (mi->context.options.push_ifconfig_defined)
    {
        /* ifconfig addresses were set statically,
         * release dynamic allocation */
        if (mi->vaddr_handle >= 0)
        {
            ifconfig_pool_release(m->ifconfig_pool, mi->vaddr_handle, true);
            mi->vaddr_handle = -1;
        }
 
        mi->context.c2.push_ifconfig_defined = true;
        mi->context.c2.push_ifconfig_local = mi->context.options.push_ifconfig_local;
        mi->context.c2.push_ifconfig_remote_netmask =
            mi->context.options.push_ifconfig_remote_netmask;
        mi->context.c2.push_ifconfig_local_alias = mi->context.options.push_ifconfig_local_alias;
 
        /* the current implementation does not allow "static IPv4, pool IPv6",
         * (see below) so issue a warning if that happens - don't break the
         * session, though, as we don't even know if this client WANTS IPv6
         */
        if (mi->context.options.ifconfig_ipv6_pool_defined
            && !mi->context.options.push_ifconfig_ipv6_defined)
        {
            msg(M_INFO,
                "MULTI_sva: WARNING: if --ifconfig-push is used for IPv4, automatic IPv6 assignment from --ifconfig-ipv6-pool does not work.  Use --ifconfig-ipv6-push for IPv6 then.");
        }
    }
    else if (m->ifconfig_pool && mi->vaddr_handle < 0) /* otherwise, choose a pool address */
    {
        in_addr_t local = 0, remote = 0;
        struct in6_addr remote_ipv6;
        const char *cn = NULL;
 
        if (!mi->context.options.duplicate_cn)
        {
            cn = tls_common_name(mi->context.c2.tls_multi, true);
        }
 
        CLEAR(remote_ipv6);
        mi->vaddr_handle =
            ifconfig_pool_acquire(m->ifconfig_pool, &local, &remote, &remote_ipv6, cn);
        if (mi->vaddr_handle >= 0)
        {
            const int tunnel_type = TUNNEL_TYPE(mi->context.c1.tuntap);
            const int tunnel_topology = TUNNEL_TOPOLOGY(mi->context.c1.tuntap);
 
            msg(M_INFO, "MULTI_sva: pool returned IPv4=%s, IPv6=%s",
                (mi->context.options.ifconfig_pool_defined ? print_in_addr_t(remote, 0, &gc)
                                                           : "(Not enabled)"),
                (mi->context.options.ifconfig_ipv6_pool_defined
                     ? print_in6_addr(remote_ipv6, 0, &gc)
                     : "(Not enabled)"));
 
            if (mi->context.options.ifconfig_pool_defined)
            {
                /* set push_ifconfig_remote_netmask from pool ifconfig address(es) */
                mi->context.c2.push_ifconfig_local = remote;
                if (tunnel_type == DEV_TYPE_TAP
                    || (tunnel_type == DEV_TYPE_TUN && tunnel_topology == TOP_SUBNET))
                {
                    mi->context.c2.push_ifconfig_remote_netmask =
                        mi->context.options.ifconfig_pool_netmask;
                    if (!mi->context.c2.push_ifconfig_remote_netmask)
                    {
                        mi->context.c2.push_ifconfig_remote_netmask =
                            mi->context.c1.tuntap->remote_netmask;
                    }
                }
                else if (tunnel_type == DEV_TYPE_TUN)
                {
                    if (tunnel_topology == TOP_P2P)
                    {
                        mi->context.c2.push_ifconfig_remote_netmask = mi->context.c1.tuntap->local;
                    }
                    else if (tunnel_topology == TOP_NET30)
                    {
                        mi->context.c2.push_ifconfig_remote_netmask = local;
                    }
                }
 
                if (mi->context.c2.push_ifconfig_remote_netmask)
                {
                    mi->context.c2.push_ifconfig_defined = true;
                }
                else
                {
                    msg(D_MULTI_ERRORS,
                        "MULTI: no --ifconfig-pool netmask parameter is available to push to %s",
                        multi_instance_string(mi, false, &gc));
                }
            }
 
            if (mi->context.options.ifconfig_ipv6_pool_defined)
            {
                mi->context.c2.push_ifconfig_ipv6_local = remote_ipv6;
                mi->context.c2.push_ifconfig_ipv6_remote = mi->context.c1.tuntap->local_ipv6;
                mi->context.c2.push_ifconfig_ipv6_netbits =
                    mi->context.options.ifconfig_ipv6_netbits;
                mi->context.c2.push_ifconfig_ipv6_defined = true;
            }
        }
        else
        {
            msg(D_MULTI_ERRORS, "MULTI: no free --ifconfig-pool addresses are available");
        }
    }
 
    /* IPv6 push_ifconfig is a bit problematic - since IPv6 shares the
     * pool handling with IPv4, the combination "static IPv4, dynamic IPv6"
     * will fail (because no pool will be allocated in this case).
     * OTOH, this doesn't make too much sense in reality - and the other
     * way round ("dynamic IPv4, static IPv6") or "both static" makes sense
     * -> and so it's implemented right now
     */
    if (mi->context.options.push_ifconfig_ipv6_defined)
    {
        mi->context.c2.push_ifconfig_ipv6_local = mi->context.options.push_ifconfig_ipv6_local;
        mi->context.c2.push_ifconfig_ipv6_remote = mi->context.options.push_ifconfig_ipv6_remote;
        mi->context.c2.push_ifconfig_ipv6_netbits = mi->context.options.push_ifconfig_ipv6_netbits;
        mi->context.c2.push_ifconfig_ipv6_defined = true;
 
        msg(M_INFO, "MULTI_sva: push_ifconfig_ipv6 %s/%d",
            print_in6_addr(mi->context.c2.push_ifconfig_ipv6_local, 0, &gc),
            mi->context.c2.push_ifconfig_ipv6_netbits);
    }
 
    gc_free(&gc);
}
 
/*
 * Set virtual address environmental variables.
 */
static void
multi_set_virtual_addr_env(struct multi_instance *mi)
{
    setenv_del(mi->context.c2.es, "ifconfig_pool_local_ip");
    setenv_del(mi->context.c2.es, "ifconfig_pool_remote_ip");
    setenv_del(mi->context.c2.es, "ifconfig_pool_netmask");
 
    if (mi->context.c2.push_ifconfig_defined)
    {
        const int tunnel_type = TUNNEL_TYPE(mi->context.c1.tuntap);
        const int tunnel_topology = TUNNEL_TOPOLOGY(mi->context.c1.tuntap);
 
        setenv_in_addr_t(mi->context.c2.es, "ifconfig_pool_remote_ip",
                         mi->context.c2.push_ifconfig_local, SA_SET_IF_NONZERO);
 
        if (tunnel_type == DEV_TYPE_TAP
            || (tunnel_type == DEV_TYPE_TUN && tunnel_topology == TOP_SUBNET))
        {
            setenv_in_addr_t(mi->context.c2.es, "ifconfig_pool_netmask",
                             mi->context.c2.push_ifconfig_remote_netmask, SA_SET_IF_NONZERO);
        }
        else if (tunnel_type == DEV_TYPE_TUN)
        {
            setenv_in_addr_t(mi->context.c2.es, "ifconfig_pool_local_ip",
                             mi->context.c2.push_ifconfig_remote_netmask, SA_SET_IF_NONZERO);
        }
    }
 
    setenv_del(mi->context.c2.es, "ifconfig_pool_local_ip6");
    setenv_del(mi->context.c2.es, "ifconfig_pool_remote_ip6");
    setenv_del(mi->context.c2.es, "ifconfig_pool_ip6_netbits");
 
    if (mi->context.c2.push_ifconfig_ipv6_defined)
    {
        setenv_in6_addr(mi->context.c2.es, "ifconfig_pool_remote",
                        &mi->context.c2.push_ifconfig_ipv6_local, SA_SET_IF_NONZERO);
        setenv_in6_addr(mi->context.c2.es, "ifconfig_pool_local",
                        &mi->context.c2.push_ifconfig_ipv6_remote, SA_SET_IF_NONZERO);
        setenv_int(mi->context.c2.es, "ifconfig_pool_ip6_netbits",
                   mi->context.c2.push_ifconfig_ipv6_netbits);
    }
}
 
/*
 * Called after client-connect script is called
 */
static void
multi_client_connect_post(struct multi_context *m, struct multi_instance *mi, const char *dc_file,
                          uint64_t *option_types_found)
{
    /* Did script generate a dynamic config file? */
    if (platform_test_file(dc_file))
    {
        options_server_import(&mi->context.options, dc_file, D_IMPORT_ERRORS | M_OPTERR,
                              CLIENT_CONNECT_OPT_MASK, option_types_found, mi->context.c2.es);
 
        /*
         * If the --client-connect script generates a config file
         * with an --ifconfig-push directive, it will override any
         * --ifconfig-push directive from the --client-config-dir
         * directory or any --ifconfig-pool dynamic address.
         */
        multi_select_virtual_addr(m, mi);
        multi_set_virtual_addr_env(mi);
    }
}
 
#ifdef ENABLE_PLUGIN
 
/*
 * Called after client-connect plug-in is called
 */
static void
multi_client_connect_post_plugin(struct multi_context *m, struct multi_instance *mi,
                                 const struct plugin_return *pr, uint64_t *option_types_found)
{
    struct plugin_return config;
 
    plugin_return_get_column(pr, &config, "config");
 
    /* Did script generate a dynamic config file? */
    if (plugin_return_defined(&config))
    {
        int i;
        for (i = 0; i < config.n; ++i)
        {
            if (config.list[i] && config.list[i]->value)
            {
                options_string_import(&mi->context.options, config.list[i]->value,
                                      D_IMPORT_ERRORS | M_OPTERR, CLIENT_CONNECT_OPT_MASK,
                                      option_types_found, mi->context.c2.es);
            }
        }
 
        /*
         * If the --client-connect script generates a config file
         * with an --ifconfig-push directive, it will override any
         * --ifconfig-push directive from the --client-config-dir
         * directory or any --ifconfig-pool dynamic address.
         */
        multi_select_virtual_addr(m, mi);
        multi_set_virtual_addr_env(mi);
    }
}
 
#endif /* ifdef ENABLE_PLUGIN */
 
 
/*
 * Called to load management-derived client-connect config
 */
enum client_connect_return
multi_client_connect_mda(struct multi_context *m, struct multi_instance *mi, bool deferred,
                         uint64_t *option_types_found)
{
    /* We never return CC_RET_DEFERRED */
    ASSERT(!deferred);
    enum client_connect_return ret = CC_RET_SKIPPED;
#ifdef ENABLE_MANAGEMENT
    if (mi->cc_config)
    {
        struct buffer_entry *be;
        for (be = mi->cc_config->head; be != NULL; be = be->next)
        {
            const char *opt = BSTR(&be->buf);
            options_string_import(&mi->context.options, opt, D_IMPORT_ERRORS | M_OPTERR,
                                  CLIENT_CONNECT_OPT_MASK, option_types_found, mi->context.c2.es);
        }
 
        /*
         * If the --client-connect script generates a config file
         * with an --ifconfig-push directive, it will override any
         * --ifconfig-push directive from the --client-config-dir
         * directory or any --ifconfig-pool dynamic address.
         */
        multi_select_virtual_addr(m, mi);
        multi_set_virtual_addr_env(mi);
 
        ret = CC_RET_SUCCEEDED;
    }
#endif /* ifdef ENABLE_MANAGEMENT */
    return ret;
}
 
static void
multi_client_connect_setenv(struct multi_instance *mi)
{
    struct gc_arena gc = gc_new();
 
    /* setenv incoming cert common name for script */
    setenv_str(mi->context.c2.es, "common_name", tls_common_name(mi->context.c2.tls_multi, true));
 
    /* setenv client real IP address */
    setenv_trusted(mi->context.c2.es, get_link_socket_info(&mi->context));
 
    /* setenv client virtual IP address */
    multi_set_virtual_addr_env(mi);
 
    /* setenv connection time */
    {
        const char *created_ascii = time_string(mi->created, 0, false, &gc);
        setenv_str(mi->context.c2.es, "time_ascii", created_ascii);
        setenv_long_long(mi->context.c2.es, "time_unix", mi->created);
    }
 
    gc_free(&gc);
}
 
static bool
multi_client_set_protocol_options(struct context *c)
{
    struct tls_multi *tls_multi = c->c2.tls_multi;
    const char *const peer_info = tls_multi->peer_info;
    struct options *o = &c->options;
 
 
    unsigned int proto = extract_iv_proto(peer_info);
    if (proto & IV_PROTO_DATA_V2)
    {
        tls_multi->use_peer_id = true;
        o->use_peer_id = true;
    }
    else if (dco_enabled(o))
    {
        msg(M_INFO, "Client does not support DATA_V2. Data channel offloading "
                    "requires DATA_V2. Dropping client.");
        auth_set_client_reason(tls_multi, "Data channel negotiation "
                                          "failed (missing DATA_V2)");
        return false;
    }
 
    /* Print a warning if we detect the client being in P2P mode and will
     * not accept our pushed ciphers */
    if (proto & IV_PROTO_NCP_P2P)
    {
        msg(M_WARN, "Note: peer reports running in P2P mode (no --pull/--client "
                    "option). It will not negotiate ciphers with this server. "
                    "Expect this connection to fail.");
    }
 
    if (proto & IV_PROTO_REQUEST_PUSH)
    {
        c->c2.push_request_received = true;
    }
 
    if (proto & IV_PROTO_TLS_KEY_EXPORT)
    {
        o->imported_protocol_flags |= CO_USE_TLS_KEY_MATERIAL_EXPORT;
    }
    else if (o->force_key_material_export)
    {
        msg(M_INFO, "PUSH: client does not support TLS Keying Material "
                    "Exporters but --force-tls-key-material-export is enabled.");
        auth_set_client_reason(tls_multi, "Client incompatible with this "
                                          "server. Keying Material Exporters (RFC 5705) "
                                          "support missing. Upgrade to a client that "
                                          "supports this feature (OpenVPN 2.6.0+).");
        return false;
    }
    if (proto & IV_PROTO_DYN_TLS_CRYPT)
    {
        o->imported_protocol_flags |= CO_USE_DYNAMIC_TLS_CRYPT;
    }
 
    if (proto & IV_PROTO_CC_EXIT_NOTIFY)
    {
        o->imported_protocol_flags |= CO_USE_CC_EXIT_NOTIFY;
    }
 
    /* Select cipher if client supports Negotiable Crypto Parameters */
 
    /* if we have already created our key, we cannot *change* our own
     * cipher -> so log the fact and push the "what we have now" cipher
     * (so the client is always told what we expect it to use)
     */
    if (get_primary_key(tls_multi)->crypto_options.key_ctx_bi.initialized)
    {
        msg(M_INFO,
            "PUSH: client wants to negotiate cipher (NCP), but "
            "server has already generated data channel keys, "
            "re-sending previously negotiated cipher '%s'",
            o->ciphername);
        return true;
    }
 
    /*
     * Push the first cipher from --data-ciphers to the client that
     * the client announces to be supporting.
     */
    char *push_cipher =
        ncp_get_best_cipher(o->ncp_ciphers, peer_info, tls_multi->remote_ciphername, &o->gc);
    if (push_cipher)
    {
        /* Enable epoch data key format if supported and AEAD cipher in use */
        if (tls_multi->session[TM_ACTIVE].opt->data_epoch_supported && (proto & IV_PROTO_DATA_EPOCH)
            && cipher_kt_mode_aead(push_cipher))
        {
            o->imported_protocol_flags |= CO_EPOCH_DATA_KEY_FORMAT;
        }
 
        o->ciphername = push_cipher;
        return true;
    }
 
    /* NCP cipher negotiation failed. Try to figure out why exactly it
     * failed and give good error messages and potentially do a fallback
     * for non NCP clients */
    struct gc_arena gc = gc_new();
    bool ret = false;
 
    const char *peer_ciphers = tls_peer_ncp_list(peer_info, &gc);
    /* If we are in a situation where we know the client ciphers, there is no
     * reason to fall back to a cipher that will not be accepted by the other
     * side, in this situation we fail the auth*/
    if (strlen(peer_ciphers) > 0)
    {
        msg(M_INFO,
            "PUSH: No common cipher between server and client. "
            "Server data-ciphers: '%s'%s, client supported ciphers '%s'",
            o->ncp_ciphers_conf, ncp_expanded_ciphers(o, &gc), peer_ciphers);
    }
    else if (tls_multi->remote_ciphername)
    {
        msg(M_INFO,
            "PUSH: No common cipher between server and client. "
            "Server data-ciphers: '%s'%s, client supports cipher '%s'",
            o->ncp_ciphers_conf, ncp_expanded_ciphers(o, &gc), tls_multi->remote_ciphername);
    }
    else
    {
        msg(M_INFO, "PUSH: No NCP or OCC cipher data received from peer.");
 
        if (o->enable_ncp_fallback)
        {
            msg(M_INFO,
                "Using data channel cipher '%s' since "
                "--data-ciphers-fallback is set.",
                o->ciphername);
            ret = true;
        }
        else
        {
            msg(M_INFO, "Use --data-ciphers-fallback with the cipher the "
                        "client is using if you want to allow the client to connect");
        }
    }
    if (!ret)
    {
        auth_set_client_reason(tls_multi, "Data channel cipher negotiation "
                                          "failed (no shared cipher)");
    }
 
    gc_free(&gc);
    return ret;
}
 
static void
ccs_delete_deferred_ret_file(struct multi_instance *mi)
{
    struct client_connect_defer_state *ccs = &(mi->client_connect_defer_state);
    if (!ccs->deferred_ret_file)
    {
        return;
    }
 
    setenv_del(mi->context.c2.es, "client_connect_deferred_file");
    if (!platform_unlink(ccs->deferred_ret_file))
    {
        msg(D_MULTI_ERRORS, "MULTI: problem deleting temporary file: %s", ccs->deferred_ret_file);
    }
    free(ccs->deferred_ret_file);
    ccs->deferred_ret_file = NULL;
}
 
static bool
ccs_gen_deferred_ret_file(struct multi_instance *mi)
{
    struct client_connect_defer_state *ccs = &(mi->client_connect_defer_state);
    struct gc_arena gc = gc_new();
    const char *fn;
 
    /* Delete file if it already exists */
    ccs_delete_deferred_ret_file(mi);
 
    fn = platform_create_temp_file(mi->context.options.tmp_dir, "ccr", &gc);
    if (!fn)
    {
        gc_free(&gc);
        return false;
    }
    ccs->deferred_ret_file = string_alloc(fn, NULL);
 
    setenv_str(mi->context.c2.es, "client_connect_deferred_file", ccs->deferred_ret_file);
 
    gc_free(&gc);
    return true;
}
 
static enum client_connect_return
ccs_test_deferred_ret_file(struct multi_instance *mi)
{
    struct client_connect_defer_state *ccs = &(mi->client_connect_defer_state);
    FILE *fp = fopen(ccs->deferred_ret_file, "r");
    if (!fp)
    {
        return CC_RET_SKIPPED;
    }
 
    enum client_connect_return ret = CC_RET_SKIPPED;
    const int c = fgetc(fp);
    switch (c)
    {
        case '0':
            ret = CC_RET_FAILED;
            break;
 
        case '1':
            ret = CC_RET_SUCCEEDED;
            break;
 
        case '2':
            ret = CC_RET_DEFERRED;
            break;
 
        case EOF:
            if (feof(fp))
            {
                ret = CC_RET_SKIPPED;
                break;
            }
 
        /* Not EOF but other error -> fall through to error state */
        default:
            /* We received an unknown/unexpected value.  Assume failure. */
            msg(M_WARN, "WARNING: Unknown/unexpected value in deferred "
                        "client-connect resultfile");
            ret = CC_RET_FAILED;
    }
    fclose(fp);
 
    return ret;
}
 
static void
ccs_delete_config_file(struct multi_instance *mi)
{
    struct client_connect_defer_state *ccs = &(mi->client_connect_defer_state);
    if (ccs->config_file)
    {
        setenv_del(mi->context.c2.es, "client_connect_config_file");
        if (!platform_unlink(ccs->config_file))
        {
            msg(D_MULTI_ERRORS, "MULTI: problem deleting temporary file: %s", ccs->config_file);
        }
        free(ccs->config_file);
        ccs->config_file = NULL;
    }
}
 
static bool
ccs_gen_config_file(struct multi_instance *mi)
{
    struct client_connect_defer_state *ccs = &(mi->client_connect_defer_state);
    struct gc_arena gc = gc_new();
    const char *fn;
 
    if (ccs->config_file)
    {
        ccs_delete_config_file(mi);
    }
 
    fn = platform_create_temp_file(mi->context.options.tmp_dir, "cc", &gc);
    if (!fn)
    {
        gc_free(&gc);
        return false;
    }
    ccs->config_file = string_alloc(fn, NULL);
 
    setenv_str(mi->context.c2.es, "client_connect_config_file", ccs->config_file);
 
    gc_free(&gc);
    return true;
}
 
static enum client_connect_return
multi_client_connect_call_plugin_v1(struct multi_context *m, struct multi_instance *mi,
                                    bool deferred, uint64_t *option_types_found)
{
    enum client_connect_return ret = CC_RET_SKIPPED;
#ifdef ENABLE_PLUGIN
    ASSERT(m);
    ASSERT(mi);
    ASSERT(option_types_found);
    struct client_connect_defer_state *ccs = &(mi->client_connect_defer_state);
 
    /* deprecated callback, use a file for passing back return info */
    if (plugin_defined(mi->context.plugins, OPENVPN_PLUGIN_CLIENT_CONNECT))
    {
        struct argv argv = argv_new();
        int call;
 
        if (!deferred)
        {
            call = OPENVPN_PLUGIN_CLIENT_CONNECT;
            if (!ccs_gen_config_file(mi) || !ccs_gen_deferred_ret_file(mi))
            {
                ret = CC_RET_FAILED;
                goto cleanup;
            }
        }
        else
        {
            call = OPENVPN_PLUGIN_CLIENT_CONNECT_DEFER;
            /* the initial call should have created these files */
            ASSERT(ccs->config_file);
            ASSERT(ccs->deferred_ret_file);
        }
 
        argv_printf(&argv, "%s", ccs->config_file);
        int plug_ret = plugin_call(mi->context.plugins, call, &argv, NULL, mi->context.c2.es);
        if (plug_ret == OPENVPN_PLUGIN_FUNC_SUCCESS)
        {
            ret = CC_RET_SUCCEEDED;
        }
        else if (plug_ret == OPENVPN_PLUGIN_FUNC_DEFERRED)
        {
            ret = CC_RET_DEFERRED;
        }
        else
        {
            msg(M_WARN, "WARNING: client-connect plugin call failed");
            ret = CC_RET_FAILED;
        }
 
 
        int file_ret = ccs_test_deferred_ret_file(mi);
 
        if (file_ret == CC_RET_FAILED)
        {
            ret = CC_RET_FAILED;
        }
        else if (ret == CC_RET_SUCCEEDED && file_ret == CC_RET_DEFERRED)
        {
            ret = CC_RET_DEFERRED;
        }
 
        /* if we still think we have succeeded, do postprocessing */
        if (ret == CC_RET_SUCCEEDED)
        {
            multi_client_connect_post(m, mi, ccs->config_file, option_types_found);
        }
cleanup:
        argv_free(&argv);
 
        if (ret != CC_RET_DEFERRED)
        {
            ccs_delete_config_file(mi);
            ccs_delete_deferred_ret_file(mi);
        }
    }
#endif /* ifdef ENABLE_PLUGIN */
    return ret;
}
 
static enum client_connect_return
multi_client_connect_call_plugin_v2(struct multi_context *m, struct multi_instance *mi,
                                    bool deferred, uint64_t *option_types_found)
{
    enum client_connect_return ret = CC_RET_SKIPPED;
#ifdef ENABLE_PLUGIN
    ASSERT(m);
    ASSERT(mi);
    ASSERT(option_types_found);
 
    int call = deferred ? OPENVPN_PLUGIN_CLIENT_CONNECT_DEFER_V2 : OPENVPN_PLUGIN_CLIENT_CONNECT_V2;
    /* V2 callback, use a plugin_return struct for passing back return info */
    if (plugin_defined(mi->context.plugins, call))
    {
        struct plugin_return pr;
 
        plugin_return_init(&pr);
 
        int plug_ret = plugin_call(mi->context.plugins, call, NULL, &pr, mi->context.c2.es);
        if (plug_ret == OPENVPN_PLUGIN_FUNC_SUCCESS)
        {
            multi_client_connect_post_plugin(m, mi, &pr, option_types_found);
            ret = CC_RET_SUCCEEDED;
        }
        else if (plug_ret == OPENVPN_PLUGIN_FUNC_DEFERRED)
        {
            ret = CC_RET_DEFERRED;
            if (!(plugin_defined(mi->context.plugins, OPENVPN_PLUGIN_CLIENT_CONNECT_DEFER_V2)))
            {
                msg(M_WARN, "A plugin that defers from the "
                            "OPENVPN_PLUGIN_CLIENT_CONNECT_V2 call must also "
                            "declare support for "
                            "OPENVPN_PLUGIN_CLIENT_CONNECT_DEFER_V2");
                ret = CC_RET_FAILED;
            }
        }
        else
        {
            msg(M_WARN, "WARNING: client-connect-v2 plugin call failed");
            ret = CC_RET_FAILED;
        }
 
 
        plugin_return_free(&pr);
    }
#endif /* ifdef ENABLE_PLUGIN */
    return ret;
}
 
static enum client_connect_return
multi_client_connect_script_deferred(struct multi_context *m, struct multi_instance *mi,
                                     uint64_t *option_types_found)
{
    ASSERT(mi);
    ASSERT(option_types_found);
    struct client_connect_defer_state *ccs = &(mi->client_connect_defer_state);
    enum client_connect_return ret = CC_RET_SKIPPED;
 
    ret = ccs_test_deferred_ret_file(mi);
 
    if (ret == CC_RET_SKIPPED)
    {
        /*
         * Skipped and deferred are equivalent in this context.
         * skipped means that the called program has not yet
         * written a return status implicitly needing more time
         * while deferred is the explicit notification that it
         * needs more time
         */
        ret = CC_RET_DEFERRED;
    }
 
    if (ret == CC_RET_SUCCEEDED)
    {
        ccs_delete_deferred_ret_file(mi);
        multi_client_connect_post(m, mi, ccs->config_file, option_types_found);
        ccs_delete_config_file(mi);
    }
    if (ret == CC_RET_FAILED)
    {
        msg(M_INFO, "MULTI: deferred --client-connect script returned CC_RET_FAILED");
        ccs_delete_deferred_ret_file(mi);
        ccs_delete_config_file(mi);
    }
    return ret;
}
 
static enum client_connect_return
multi_client_connect_call_script(struct multi_context *m, struct multi_instance *mi, bool deferred,
                                 uint64_t *option_types_found)
{
    if (deferred)
    {
        return multi_client_connect_script_deferred(m, mi, option_types_found);
    }
    ASSERT(m);
    ASSERT(mi);
 
    enum client_connect_return ret = CC_RET_SKIPPED;
    struct client_connect_defer_state *ccs = &(mi->client_connect_defer_state);
 
    if (mi->context.options.client_connect_script)
    {
        struct argv argv = argv_new();
        struct gc_arena gc = gc_new();
 
        setenv_str(mi->context.c2.es, "script_type", "client-connect");
 
        if (!ccs_gen_config_file(mi) || !ccs_gen_deferred_ret_file(mi))
        {
            ret = CC_RET_FAILED;
            goto cleanup;
        }
 
        argv_parse_cmd(&argv, mi->context.options.client_connect_script);
        argv_printf_cat(&argv, "%s", ccs->config_file);
 
        if (openvpn_run_script(&argv, mi->context.c2.es, 0, "--client-connect"))
        {
            if (ccs_test_deferred_ret_file(mi) == CC_RET_DEFERRED)
            {
                ret = CC_RET_DEFERRED;
            }
            else
            {
                multi_client_connect_post(m, mi, ccs->config_file, option_types_found);
                ret = CC_RET_SUCCEEDED;
            }
        }
        else
        {
            ret = CC_RET_FAILED;
        }
cleanup:
        if (ret != CC_RET_DEFERRED)
        {
            ccs_delete_config_file(mi);
            ccs_delete_deferred_ret_file(mi);
        }
        argv_free(&argv);
        gc_free(&gc);
    }
    return ret;
}
 
static bool
multi_client_setup_dco_initial(struct multi_context *m, struct multi_instance *mi,
                               struct gc_arena *gc)
{
    if (!dco_enabled(&mi->context.options))
    {
        /* DCO not enabled, nothing to do, return sucess */
        return true;
    }
    int ret = dco_multi_add_new_peer(m, mi);
    if (ret < 0)
    {
        msg(D_DCO, "Cannot add peer to DCO for %s: %s (%d)", multi_instance_string(mi, false, gc),
            strerror(-ret), ret);
        return false;
    }
 
    return true;
}
 
static bool
multi_client_generate_tls_keys(struct context *c)
{
    struct frame *frame_fragment = NULL;
#ifdef ENABLE_FRAGMENT
    if (c->options.ce.fragment)
    {
        frame_fragment = &c->c2.frame_fragment;
    }
#endif
    struct tls_session *session = &c->c2.tls_multi->session[TM_ACTIVE];
    if (!tls_session_update_crypto_params(c->c2.tls_multi, session, &c->options, &c->c2.frame,
                                          frame_fragment, get_link_socket_info(c),
                                          &c->c1.tuntap->dco))
    {
        msg(D_TLS_ERRORS, "TLS Error: initializing data channel failed");
        register_signal(c->sig, SIGUSR1, "process-push-msg-failed");
        return false;
    }
 
    return true;
}
 
static void
multi_client_connect_late_setup(struct multi_context *m, struct multi_instance *mi,
                                const uint64_t option_types_found)
{
    ASSERT(m);
    ASSERT(mi);
 
    struct gc_arena gc = gc_new();
    /*
     * Process sourced options.
     */
    do_deferred_options(&mi->context, option_types_found, false);
 
    /*
     * make sure we got ifconfig settings from somewhere
     */
    if (!mi->context.c2.push_ifconfig_defined)
    {
        msg(D_MULTI_ERRORS,
            "MULTI: no dynamic or static remote "
            "--ifconfig address is available for %s",
            multi_instance_string(mi, false, &gc));
    }
 
    /*
     * make sure that ifconfig settings comply with constraints
     */
    if (!ifconfig_push_constraint_satisfied(&mi->context))
    {
        const char *ifconfig_constraint_network =
            print_in_addr_t(mi->context.options.push_ifconfig_constraint_network, 0, &gc);
        const char *ifconfig_constraint_netmask =
            print_in_addr_t(mi->context.options.push_ifconfig_constraint_netmask, 0, &gc);
 
        /* JYFIXME -- this should cause the connection to fail */
        msg(D_MULTI_ERRORS,
            "MULTI ERROR: primary virtual IP for %s (%s) "
            "violates tunnel network/netmask constraint (%s/%s)",
            multi_instance_string(mi, false, &gc),
            print_in_addr_t(mi->context.c2.push_ifconfig_local, 0, &gc),
            ifconfig_constraint_network, ifconfig_constraint_netmask);
    }
 
    /* set our client's VPN endpoint for status reporting purposes */
    mi->reporting_addr = mi->context.c2.push_ifconfig_local;
    mi->reporting_addr_ipv6 = mi->context.c2.push_ifconfig_ipv6_local;
 
    /* set context-level authentication flag */
    mi->context.c2.tls_multi->multi_state = CAS_CONNECT_DONE;
 
    /* Since dco-win maintains iroute routing table (subnet -> peer),
     * peer must be added before iroutes. For other platforms it doesn't matter. */
 
    /* authentication complete, calculate dynamic client specific options */
    if (!multi_client_set_protocol_options(&mi->context))
    {
        mi->context.c2.tls_multi->multi_state = CAS_FAILED;
    }
    /* only continue if setting protocol options worked */
    else if (!multi_client_setup_dco_initial(m, mi, &gc))
    {
        mi->context.c2.tls_multi->multi_state = CAS_FAILED;
    }
    /* Generate data channel keys only if setting protocol options
     * and DCO initial setup has not failed */
    else if (!multi_client_generate_tls_keys(&mi->context))
    {
        mi->context.c2.tls_multi->multi_state = CAS_FAILED;
    }
 
    /* dco peer has been added, it is now safe for Windows to add iroutes */
 
    /*
     * For routed tunnels, set up internal route to endpoint
     * plus add all iroute routes.
     */
    if (TUNNEL_TYPE(mi->context.c1.tuntap) == DEV_TYPE_TUN)
    {
        if (mi->context.c2.push_ifconfig_defined)
        {
            multi_learn_in_addr_t(m, mi, mi->context.c2.push_ifconfig_local, -1, true);
            msg(D_MULTI_LOW, "MULTI: primary virtual IP for %s: %s",
                multi_instance_string(mi, false, &gc),
                print_in_addr_t(mi->context.c2.push_ifconfig_local, 0, &gc));
        }
 
        if (mi->context.c2.push_ifconfig_ipv6_defined)
        {
            multi_learn_in6_addr(m, mi, mi->context.c2.push_ifconfig_ipv6_local, -1, true);
            /* TODO: find out where addresses are "unlearned"!! */
            const char *ifconfig_local_ipv6 =
                print_in6_addr(mi->context.c2.push_ifconfig_ipv6_local, 0, &gc);
            msg(D_MULTI_LOW, "MULTI: primary virtual IPv6 for %s: %s",
                multi_instance_string(mi, false, &gc), ifconfig_local_ipv6);
        }
 
        /* add routes locally, pointing to new client, if
         * --iroute options have been specified */
        multi_add_iroutes(m, mi);
 
        /*
         * iroutes represent subnets which are "owned" by a particular
         * client.  Therefore, do not actually push a route to a client
         * if it matches one of the client's iroutes.
         */
        remove_iroutes_from_push_route_list(&mi->context.options);
    }
    else if (mi->context.options.iroutes)
    {
        msg(D_MULTI_ERRORS,
            "MULTI: --iroute options rejected for %s -- iroute "
            "only works with tun-style tunnels",
            multi_instance_string(mi, false, &gc));
    }
 
    /* send push reply if ready */
    if (mi->context.c2.push_request_received)
    {
        process_incoming_push_request(&mi->context);
    }
    gc_free(&gc);
}
 
static void
multi_client_connect_early_setup(struct multi_context *m, struct multi_instance *mi)
{
    ASSERT(mi->context.c1.tuntap);
    /*
     * lock down the common name and cert hashes so they can't change
     * during future TLS renegotiations
     */
    tls_lock_common_name(mi->context.c2.tls_multi);
    tls_lock_cert_hash_set(mi->context.c2.tls_multi);
 
    /* generate a msg() prefix for this client instance */
    generate_prefix(mi);
 
    /* delete instances of previous clients with same common-name */
    if (!mi->context.options.duplicate_cn)
    {
        multi_delete_dup(m, mi);
    }
 
    /* reset pool handle to null */
    mi->vaddr_handle = -1;
 
    /* do --client-connect setenvs */
    multi_select_virtual_addr(m, mi);
 
    multi_client_connect_setenv(mi);
}
 
static enum client_connect_return
multi_client_connect_compress_migrate(struct multi_context *m, struct multi_instance *mi,
                                      bool deferred, uint64_t *option_types_found)
{
#ifdef USE_COMP
    struct options *o = &mi->context.options;
    const char *const peer_info = mi->context.c2.tls_multi->peer_info;
 
    if (o->comp.flags & COMP_F_MIGRATE && mi->context.c2.tls_multi->remote_usescomp)
    {
        if (peer_info && strstr(peer_info, "IV_COMP_STUBv2=1"))
        {
            push_option(o, "compress stub-v2", M_USAGE);
        }
        else
        {
            /* Client is old and does not support STUBv2 but since it
             * announced comp-lzo via OCC we assume it uses comp-lzo, so
             * switch to that and push the uncompressed variant. */
            push_option(o, "comp-lzo no", M_USAGE);
            o->comp.alg = COMP_ALG_STUB;
            *option_types_found |= OPT_P_COMP;
        }
    }
#endif
    return CC_RET_SUCCEEDED;
}
 
static enum client_connect_return
multi_client_connect_source_ccd(struct multi_context *m, struct multi_instance *mi, bool deferred,
                                uint64_t *option_types_found)
{
    /* Since we never return a CC_RET_DEFERRED, this indicates a serious
     * problem */
    ASSERT(!deferred);
    enum client_connect_return ret = CC_RET_SKIPPED;
    if (mi->context.options.client_config_dir)
    {
        struct gc_arena gc = gc_new();
        const char *ccd_file = NULL;
 
        const char *ccd_client =
            platform_gen_path(mi->context.options.client_config_dir,
                              tls_common_name(mi->context.c2.tls_multi, false), &gc);
 
        const char *ccd_default =
            platform_gen_path(mi->context.options.client_config_dir, CCD_DEFAULT, &gc);
 
 
        /* try common-name file */
        if (platform_test_file(ccd_client))
        {
            ccd_file = ccd_client;
        }
        /* try default file */
        else if (platform_test_file(ccd_default))
        {
            ccd_file = ccd_default;
        }
 
        if (ccd_file)
        {
            options_server_import(&mi->context.options, ccd_file, D_IMPORT_ERRORS | M_OPTERR,
                                  CLIENT_CONNECT_OPT_MASK, option_types_found, mi->context.c2.es);
            /*
             * Select a virtual address from either --ifconfig-push in
             * --client-config-dir file or --ifconfig-pool.
             */
            multi_select_virtual_addr(m, mi);
 
            multi_client_connect_setenv(mi);
 
            ret = CC_RET_SUCCEEDED;
        }
        gc_free(&gc);
    }
    return ret;
}
 
typedef enum client_connect_return (*multi_client_connect_handler)(
    struct multi_context *m, struct multi_instance *mi, bool from_deferred,
    uint64_t *option_types_found);
 
static const multi_client_connect_handler client_connect_handlers[] = {
    multi_client_connect_compress_migrate,
    multi_client_connect_source_ccd,
    multi_client_connect_call_plugin_v1,
    multi_client_connect_call_plugin_v2,
    multi_client_connect_call_script,
    multi_client_connect_mda,
    NULL,
};
 
static bool
override_locked_username(struct multi_instance *mi)
{
    struct tls_multi *multi = mi->context.c2.tls_multi;
    struct options *options = &mi->context.options;
    struct tls_session *session = &multi->session[TM_ACTIVE];
 
    if (!multi->locked_username)
    {
        msg(D_MULTI_ERRORS, "MULTI: Ignoring override-username as no "
                            "user/password method is enabled. Enable "
                            "--management-client-auth, --auth-user-pass-verify, or a "
                            "plugin with user/password verify capability.");
        return false;
    }
 
    if (!multi->locked_original_username
        && strcmp(multi->locked_username, options->override_username) != 0)
    {
        /* Check if the username length is acceptable */
        if (!ssl_verify_username_length(session, options->override_username))
        {
            return false;
        }
 
        multi->locked_original_username = multi->locked_username;
        multi->locked_username = strdup(options->override_username);
 
        /* Override also the common name if username should be set as common
         * name */
        if ((session->opt->ssl_flags & SSLF_USERNAME_AS_COMMON_NAME))
        {
            set_common_name(session, multi->locked_username);
            free(multi->locked_cn);
            multi->locked_cn = NULL;
            tls_lock_common_name(multi);
        }
 
        /* Regenerate the auth-token if enabled */
        if (multi->auth_token_initial)
        {
            struct user_pass up;
            CLEAR(up);
            strncpynt(up.username, multi->locked_username, sizeof(up.username));
 
            generate_auth_token(&up, multi);
        }
 
        msg(D_MULTI_LOW,
            "MULTI: Note, override-username changes username "
            "from '%s' to '%s'",
            multi->locked_original_username, multi->locked_username);
    }
    return true;
}
/*
 * Called as soon as the SSL/TLS connection is authenticated.
 *
 * Will collect the client specific configuration from the different
 * sources like ccd files, connect plugins and management interface.
 *
 * This method starts with cas_context CAS_PENDING and will move the
 * state machine to either CAS_SUCCEEDED on success or
 * CAS_FAILED/CAS_PARTIAL on failure.
 *
 * Instance-specific directives to be processed (CLIENT_CONNECT_OPT_MASK)
 * include:
 *
 *   iroute start-ip end-ip
 *   ifconfig-push local remote-netmask
 *   push
 *
 *
 */
static void
multi_connection_established(struct multi_context *m, struct multi_instance *mi)
{
    /* We are only called for the CAS_PENDING_x states, so we
     * can ignore other states here */
    bool from_deferred = (mi->context.c2.tls_multi->multi_state != CAS_PENDING);
 
    int *cur_handler_index = &mi->client_connect_defer_state.cur_handler_index;
    uint64_t *option_types_found = &mi->client_connect_defer_state.option_types_found;
 
    /* We are called for the first time */
    if (!from_deferred)
    {
        *cur_handler_index = 0;
        *option_types_found = 0;
        /* Initially we have no handler that has returned a result */
        mi->context.c2.tls_multi->multi_state = CAS_PENDING_DEFERRED;
 
        multi_client_connect_early_setup(m, mi);
    }
 
    bool cc_succeeded = true;
 
    while (cc_succeeded && client_connect_handlers[*cur_handler_index] != NULL)
    {
        enum client_connect_return ret;
        ret = client_connect_handlers[*cur_handler_index](m, mi, from_deferred, option_types_found);
 
        from_deferred = false;
 
        switch (ret)
        {
            case CC_RET_SUCCEEDED:
                /*
                 * Remember that we already had at least one handler
                 * returning a result should we go to into deferred state
                 */
                mi->context.c2.tls_multi->multi_state = CAS_PENDING_DEFERRED_PARTIAL;
                break;
 
            case CC_RET_SKIPPED:
                /*
                 * Move on with the next handler without modifying any
                 * other state
                 */
                break;
 
            case CC_RET_DEFERRED:
                /*
                 * we already set multi_status to DEFERRED_RESULT or
                 * DEFERRED_NO_RESULT. We just return
                 * from the function as having multi_status
                 */
                return;
 
            case CC_RET_FAILED:
                /*
                 * One handler failed. We abort the chain and set the final
                 * result to failed
                 */
                cc_succeeded = false;
                break;
 
            default:
                ASSERT(0);
        }
 
        /*
         * Check for "disable" directive in client-config-dir file
         * or config file generated by --client-connect script.
         */
        if (mi->context.options.disable)
        {
            msg(D_MULTI_ERRORS, "MULTI: client has been rejected due to "
                                "'disable' directive");
            cc_succeeded = false;
        }
 
        (*cur_handler_index)++;
    }
 
    if (mi->context.options.override_username)
    {
        if (!override_locked_username(mi))
        {
            cc_succeeded = false;
        }
    }
 
    /* Check if we have forbidding options in the current mode */
    if (dco_enabled(&mi->context.options)
        && !dco_check_option(D_MULTI_ERRORS, &mi->context.options))
    {
        msg(D_MULTI_ERRORS, "MULTI: client has been rejected due to incompatible DCO options");
        cc_succeeded = false;
    }
 
    if (!check_compression_settings_valid(&mi->context.options.comp, D_MULTI_ERRORS))
    {
        msg(D_MULTI_ERRORS, "MULTI: client has been rejected due to invalid compression options");
        cc_succeeded = false;
    }
 
    if (cc_succeeded)
    {
        multi_client_connect_late_setup(m, mi, *option_types_found);
    }
    else
    {
        /* run the disconnect script if we had a connect script that
         * did not fail */
        if (mi->context.c2.tls_multi->multi_state == CAS_PENDING_DEFERRED_PARTIAL)
        {
            multi_client_disconnect_script(m, mi);
        }
 
        mi->context.c2.tls_multi->multi_state = CAS_FAILED;
    }
 
    /* increment number of current authenticated clients */
    ++m->n_clients;
    --mi->n_clients_delta;
 
#ifdef ENABLE_MANAGEMENT
    if (management)
    {
        management_connection_established(management, &mi->context.c2.mda_context,
                                          mi->context.c2.es);
    }
#endif
}
 
#ifdef ENABLE_ASYNC_PUSH
/*
 * Called when inotify event is fired, which happens when acf
 * or connect-status file is closed or deleted.
 * Continues authentication and sends push_reply
 * (or be deferred again by client-connect)
 */
void
multi_process_file_closed(struct multi_context *m, const unsigned int mpp_flags)
{
    char buffer[INOTIFY_EVENT_BUFFER_SIZE];
    ssize_t buffer_i = 0;
    ssize_t r = read(m->top.c2.inotify_fd, buffer, INOTIFY_EVENT_BUFFER_SIZE);
    if (r < 0)
    {
        msg(M_WARN | M_ERRNO, "MULTI: multi_process_file_closed error");
        return;
    }
 
    while (buffer_i < r)
    {
        /* parse inotify events */
        struct inotify_event *pevent = (struct inotify_event *)&buffer[buffer_i];
        size_t event_size = sizeof(struct inotify_event) + pevent->len;
        buffer_i += event_size;
 
        msg(D_MULTI_DEBUG, "MULTI: modified fd %d, mask %d", pevent->wd, pevent->mask);
 
        struct multi_instance *mi =
            hash_lookup(m->inotify_watchers, (void *)(uintptr_t)pevent->wd);
 
        if (pevent->mask & IN_CLOSE_WRITE)
        {
            if (mi)
            {
                /* continue authentication, perform NCP negotiation and send push_reply */
                multi_process_post(m, mi, mpp_flags);
            }
            else
            {
                msg(D_MULTI_ERRORS, "MULTI: multi_instance not found!");
            }
        }
        else if (pevent->mask & IN_IGNORED)
        {
            /* this event is _always_ fired when watch is removed or file is deleted */
            if (mi)
            {
                hash_remove(m->inotify_watchers, (void *)(uintptr_t)pevent->wd);
                mi->inotify_watch = -1;
            }
        }
        else
        {
            msg(D_MULTI_ERRORS, "MULTI: unknown mask %d", pevent->mask);
        }
    }
}
#endif /* ifdef ENABLE_ASYNC_PUSH */
 
/*
 * Add a mbuf buffer to a particular
 * instance.
 */
void
multi_add_mbuf(struct multi_context *m, struct multi_instance *mi, struct mbuf_buffer *mb)
{
    if (multi_output_queue_ready(m, mi))
    {
        struct mbuf_item item;
        item.buffer = mb;
        item.instance = mi;
        mbuf_add_item(m->mbuf, &item);
    }
    else
    {
        msg(D_MULTI_DROPPED, "MULTI: packet dropped due to output saturation (multi_add_mbuf)");
    }
}
 
/*
 * Add a packet to a client instance output queue.
 */
static inline void
multi_unicast(struct multi_context *m, const struct buffer *buf, struct multi_instance *mi)
{
    struct mbuf_buffer *mb;
 
    if (BLEN(buf) > 0)
    {
        mb = mbuf_alloc_buf(buf);
        mb->flags = MF_UNICAST;
        multi_add_mbuf(m, mi, mb);
        mbuf_free_buf(mb);
    }
}
 
/*
 * Broadcast a packet to all clients.
 */
static void
multi_bcast(struct multi_context *m, const struct buffer *buf,
            const struct multi_instance *sender_instance, uint16_t vid)
{
    struct mbuf_buffer *mb;
 
    if (BLEN(buf) > 0)
    {
#ifdef MULTI_DEBUG_EVENT_LOOP
        printf("BCAST len=%d\n", BLEN(buf));
#endif
        mb = mbuf_alloc_buf(buf);
 
        for (uint32_t i = 0; i <= m->max_peerid; i++)
        {
            struct multi_instance *mi = m->instances[i];
 
            if (mi && mi != sender_instance && !mi->halt)
            {
                if (vid != 0 && vid != mi->context.options.vlan_pvid)
                {
                    continue;
                }
                multi_add_mbuf(m, mi, mb);
            }
        }
        mbuf_free_buf(mb);
    }
}
 
/*
 * Given a time delta, indicating that we wish to be
 * awoken by the scheduler at time now + delta, figure
 * a sigma parameter (in microseconds) that represents
 * a sort of fuzz factor around delta, so that we're
 * really telling the scheduler to wake us up any time
 * between now + delta - sigma and now + delta + sigma.
 *
 * The sigma parameter helps the scheduler to run more efficiently.
 * Sigma should be no larger than TV_WITHIN_SIGMA_MAX_USEC
 */
static inline unsigned int
compute_wakeup_sigma(const struct timeval *delta)
{
    ASSERT(delta->tv_sec >= 0);
    ASSERT(delta->tv_usec >= 0);
    if (delta->tv_sec < 1)
    {
        /* if < 1 sec, fuzz = # of microseconds / 8 */
        return (unsigned int)(delta->tv_usec >> 3);
    }
    else
    {
        /* if < 10 minutes, fuzz = 13.1% of timeout */
        if (delta->tv_sec < 600)
        {
            return (unsigned int)(delta->tv_sec << 17);
        }
        else
        {
            return 120 * 1000000; /* if >= 10 minutes, fuzz = 2 minutes */
        }
    }
}
 
static void
multi_schedule_context_wakeup(struct multi_context *m, struct multi_instance *mi)
{
    /* calculate an absolute wakeup time */
    ASSERT(!openvpn_gettimeofday(&mi->wakeup, NULL));
    tv_add(&mi->wakeup, &mi->context.c2.timeval);
 
    /* tell scheduler to wake us up at some point in the future */
    schedule_add_entry(m->schedule, (struct schedule_entry *)mi, &mi->wakeup,
                       compute_wakeup_sigma(&mi->context.c2.timeval));
}
 
#if defined(ENABLE_ASYNC_PUSH)
static void
add_inotify_file_watch(struct multi_context *m, struct multi_instance *mi, int inotify_fd,
                       const char *file)
{
    /* watch acf file */
    int watch_descriptor = inotify_add_watch(inotify_fd, file, IN_CLOSE_WRITE | IN_ONESHOT);
    if (watch_descriptor >= 0)
    {
        if (mi->inotify_watch != -1)
        {
            hash_remove(m->inotify_watchers, (void *)(uintptr_t)mi->inotify_watch);
        }
        hash_add(m->inotify_watchers, (void *)(uintptr_t)watch_descriptor, mi, true);
        mi->inotify_watch = watch_descriptor;
    }
    else
    {
        msg(M_NONFATAL | M_ERRNO, "MULTI: inotify_add_watch error");
    }
}
#endif /* if defined(ENABLE_ASYNC_PUSH) */
 
/*
 * Figure instance-specific timers, convert
 * earliest to absolute time in mi->wakeup,
 * call scheduler with our future wakeup time.
 *
 * Also close context on signal.
 */
bool
multi_process_post(struct multi_context *m, struct multi_instance *mi, const unsigned int flags)
{
    bool ret = true;
 
    if (!IS_SIG(&mi->context)
        && ((flags & MPP_PRE_SELECT)))
    {
#if defined(ENABLE_ASYNC_PUSH)
        bool was_unauthenticated = true;
        struct key_state *ks = NULL;
        if (mi->context.c2.tls_multi)
        {
            ks = &mi->context.c2.tls_multi->session[TM_ACTIVE].key[KS_PRIMARY];
            was_unauthenticated = (ks->authenticated == KS_AUTH_FALSE);
        }
#endif
 
        /* figure timeouts and fetch possible outgoing
         * to_link packets (such as ping or TLS control) */
        pre_select(&mi->context);
 
#if defined(ENABLE_ASYNC_PUSH)
        /*
         * if we see the state transition from unauthenticated to deferred
         * and an auth_control_file, we assume it got just added and add
         * inotify watch to that file
         */
        if (ks && ks->plugin_auth.auth_control_file && was_unauthenticated
            && (ks->authenticated == KS_AUTH_DEFERRED))
        {
            add_inotify_file_watch(m, mi, m->top.c2.inotify_fd, ks->plugin_auth.auth_control_file);
        }
        if (ks && ks->script_auth.auth_control_file && was_unauthenticated
            && (ks->authenticated == KS_AUTH_DEFERRED))
        {
            add_inotify_file_watch(m, mi, m->top.c2.inotify_fd, ks->script_auth.auth_control_file);
        }
#endif
 
        if (!IS_SIG(&mi->context))
        {
            /* connection is "established" when SSL/TLS key negotiation succeeds
             * and (if specified) auth user/pass succeeds */
 
            if (is_cas_pending(mi->context.c2.tls_multi->multi_state))
            {
                multi_connection_established(m, mi);
            }
#if defined(ENABLE_ASYNC_PUSH)
            if (is_cas_pending(mi->context.c2.tls_multi->multi_state)
                && mi->client_connect_defer_state.deferred_ret_file)
            {
                add_inotify_file_watch(m, mi, m->top.c2.inotify_fd,
                                       mi->client_connect_defer_state.deferred_ret_file);
            }
#endif
            /* tell scheduler to wake us up at some point in the future */
            multi_schedule_context_wakeup(m, mi);
        }
    }
 
    if (IS_SIG(&mi->context))
    {
        if (flags & MPP_CLOSE_ON_SIGNAL)
        {
            multi_close_instance_on_signal(m, mi);
            ret = false;
        }
    }
    else
    {
        /* continue to pend on output? */
        multi_set_pending(m, ANY_OUT(&mi->context) ? mi : NULL);
 
#ifdef MULTI_DEBUG_EVENT_LOOP
        printf("POST %s[%d] to=%d lo=%d/%d w=%" PRIi64 "/%ld\n", id(mi), (int)(mi == m->pending),
               mi ? mi->context.c2.to_tun.len : -1, mi ? mi->context.c2.to_link.len : -1,
               (mi && mi->context.c2.fragment) ? mi->context.c2.fragment->outgoing.len : -1,
               (int64_t)mi->context.c2.timeval.tv_sec, (long)mi->context.c2.timeval.tv_usec);
#endif
    }
 
    if ((flags & MPP_RECORD_TOUCH) && m->mpp_touched)
    {
        *m->mpp_touched = mi;
    }
 
    return ret;
}
 
static void
multi_process_float(struct multi_context *m, struct multi_instance *mi, struct link_socket *sock)
{
    struct mroute_addr real = { 0 };
    struct hash *hash = m->hash;
    struct gc_arena gc = gc_new();
 
    if (mi->real.type & MR_WITH_PROTO)
    {
        real.type |= MR_WITH_PROTO;
        real.proto = sock->info.proto;
    }
 
    if (!mroute_extract_openvpn_sockaddr(&real, &m->top.c2.from.dest, true))
    {
        goto done;
    }
 
    const uint32_t hv = hash_value(hash, &real);
    struct hash_bucket *bucket = hash_bucket(hash, hv);
 
    /* make sure that we don't float to an address taken by another client */
    struct hash_element *he = hash_lookup_fast(hash, bucket, &real, hv);
    if (he)
    {
        struct multi_instance *ex_mi = (struct multi_instance *)he->value;
 
        struct tls_multi *m1 = mi->context.c2.tls_multi;
        struct tls_multi *m2 = ex_mi->context.c2.tls_multi;
 
        /* do not float if target address is taken by client with another cert */
        if (!cert_hash_compare(m1->locked_cert_hash_set, m2->locked_cert_hash_set))
        {
            msg(D_MULTI_LOW, "Disallow float to an address taken by another client %s",
                multi_instance_string(ex_mi, false, &gc));
 
            mi->context.c2.buf.len = 0;
 
            goto done;
        }
 
        /* It doesn't make sense to let a peer float to the address it already
         * has, so we disallow it. This can happen if a DCO netlink notification
         * gets lost and we miss a floating step.
         */
        if (m1->peer_id == m2->peer_id)
        {
            msg(M_WARN,
                "disallowing peer %" PRIu32 " (%s) from floating to "
                "its own address (%s)",
                m1->peer_id, tls_common_name(mi->context.c2.tls_multi, false),
                mroute_addr_print(&mi->real, &gc));
            goto done;
        }
 
        msg(D_MULTI_LOW,
            "closing instance %s due to float collision with %s "
            "using the same certificate",
            multi_instance_string(ex_mi, false, &gc), multi_instance_string(mi, false, &gc));
        multi_close_instance(m, ex_mi, false);
    }
 
    msg(D_MULTI_MEDIUM, "peer %" PRIu32 " (%s) floated from %s to %s",
        mi->context.c2.tls_multi->peer_id, tls_common_name(mi->context.c2.tls_multi, false),
        mroute_addr_print_ex(&mi->real, MAPF_SHOW_FAMILY, &gc),
        mroute_addr_print_ex(&real, MAPF_SHOW_FAMILY, &gc));
 
    /* remove old address from hash table before changing address */
    ASSERT(hash_remove(m->hash, &mi->real));
 
    /* change external network address of the remote peer */
    mi->real = real;
    generate_prefix(mi);
 
    mi->context.c2.from = m->top.c2.from;
    mi->context.c2.to_link_addr = &mi->context.c2.from;
 
    /* inherit parent link_socket and link_socket_info */
    mi->context.c2.link_sockets[0] = sock;
    mi->context.c2.link_socket_infos[0]->lsa->actual = m->top.c2.from;
 
    tls_update_remote_addr(mi->context.c2.tls_multi, &mi->context.c2.from);
 
    ASSERT(hash_add(m->hash, &mi->real, mi, false));
 
#ifdef ENABLE_MANAGEMENT
    ASSERT(hash_add(m->cid_hash, &mi->context.c2.mda_context.cid, mi, true));
#endif
 
done:
    gc_free(&gc);
}
 
/*
 * Called when an instance should be closed due to the
 * reception of a soft signal.
 */
void
multi_close_instance_on_signal(struct multi_context *m, struct multi_instance *mi)
{
    remap_signal(&mi->context);
    set_prefix(mi);
    print_signal(mi->context.sig, "client-instance", D_MULTI_LOW);
    clear_prefix();
    multi_close_instance(m, mi, false);
}
 
#if (defined(ENABLE_DCO) && (defined(TARGET_LINUX) || defined(TARGET_FREEBSD))) \
    || defined(ENABLE_MANAGEMENT)
static void
multi_signal_instance(struct multi_context *m, struct multi_instance *mi, const int sig)
{
    mi->context.sig->signal_received = sig;
    multi_close_instance_on_signal(m, mi);
}
#endif
 
#if defined(ENABLE_DCO)
static void
process_incoming_del_peer(struct multi_context *m, struct multi_instance *mi, dco_context_t *dco)
{
    const char *reason = "ovpn-dco: unknown reason";
    switch (dco->dco_del_peer_reason)
    {
        case OVPN_DEL_PEER_REASON_EXPIRED:
            reason = "ovpn-dco: ping expired";
            break;
 
        case OVPN_DEL_PEER_REASON_TRANSPORT_ERROR:
            reason = "ovpn-dco: transport error";
            break;
 
        case OVPN_DEL_PEER_REASON_TRANSPORT_DISCONNECT:
            reason = "ovpn-dco: transport disconnected";
            break;
 
        case OVPN_DEL_PEER_REASON_USERSPACE:
            /* We assume that is ourselves. Unfortunately, sometimes these
             * events happen with enough delay that they can have an order of
             *
             * dco_del_peer x
             * [new client connecting]
             * dco_new_peer x
             * event from dco_del_peer arrives.
             *
             * if we do not ignore this we get desynced with the kernel
             * since we assume the peer-id is free again. The other way would
             * be to send a dco_del_peer again
             */
            return;
    }
 
    /* When kernel already deleted the peer, the socket is no longer
     * installed, and we do not need to clean up the state in the kernel */
    mi->context.c2.tls_multi->dco_peer_id = -1;
    mi->context.sig->signal_text = reason;
    multi_signal_instance(m, mi, SIGTERM);
}
 
void
multi_process_incoming_dco(dco_context_t *dco)
{
    ASSERT(dco->c->multi);
 
    struct multi_context *m = dco->c->multi;
 
    int peer_id = dco->dco_message_peer_id;
 
    /* no peer-specific message delivered -> nothing to process.
     * bail out right away
     */
    if (peer_id < 0)
    {
        return;
    }
 
    if (((uint32_t)peer_id < m->max_clients) && m->instances[peer_id])
    {
        struct multi_instance *mi = m->instances[peer_id];
        set_prefix(mi);
        if (dco->dco_message_type == OVPN_CMD_DEL_PEER)
        {
            process_incoming_del_peer(m, mi, dco);
        }
        else if (dco->dco_message_type == OVPN_CMD_FLOAT_PEER)
        {
            ASSERT(mi->context.c2.link_sockets[0]);
            extract_dco_float_peer_addr(mi->context.c2.link_sockets[0]->info.af,
                                        &m->top.c2.from.dest,
                                        (struct sockaddr *)&dco->dco_float_peer_ss);
            multi_process_float(m, mi, mi->context.c2.link_sockets[0]);
            CLEAR(dco->dco_float_peer_ss);
        }
        else if (dco->dco_message_type == OVPN_CMD_SWAP_KEYS)
        {
            tls_session_soft_reset(mi->context.c2.tls_multi);
        }
        clear_prefix();
    }
    else
    {
        msglvl_t msglevel = D_DCO;
        if (dco->dco_message_type == OVPN_CMD_DEL_PEER
            && dco->dco_del_peer_reason == OVPN_DEL_PEER_REASON_USERSPACE)
        {
            /* we receive OVPN_CMD_DEL_PEER message with reason USERSPACE
             * after we kill the peer ourselves. This peer may have already
             * been deleted, so we end up here.
             * In this case, print the following debug message with DCO_DEBUG
             * level only to avoid polluting the standard DCO level with this
             * harmless event.
             */
            msglevel = D_DCO_DEBUG;
        }
        msg(msglevel,
            "Received DCO message for unknown peer-id: %d, "
            "type %d, del_peer_reason %d",
            peer_id, dco->dco_message_type, dco->dco_del_peer_reason);
    }
}
#endif /* if defined(ENABLE_DCO) */
 
/*
 * Process packets in the TCP/UDP socket -> TUN/TAP interface direction,
 * i.e. client -> server direction.
 */
bool
multi_process_incoming_link(struct multi_context *m, struct multi_instance *instance,
                            const unsigned int mpp_flags, struct link_socket *sock)
{
    struct gc_arena gc = gc_new();
 
    struct context *c;
    struct mroute_addr src, dest;
    unsigned int mroute_flags;
    struct multi_instance *mi;
    bool ret = true;
    bool floated = false;
 
    if (m->pending)
    {
        return true;
    }
 
    if (!instance)
    {
#ifdef MULTI_DEBUG_EVENT_LOOP
        printf("TCP/UDP -> TUN [%d]\n", BLEN(&m->top.c2.buf));
#endif
        multi_set_pending(m, multi_get_create_instance_udp(m, &floated, sock));
    }
    else
    {
        multi_set_pending(m, instance);
    }
 
    if (m->pending)
    {
        set_prefix(m->pending);
 
        /* get instance context */
        c = &m->pending->context;
 
        if (!instance)
        {
            /* transfer packet pointer from top-level context buffer to instance */
            c->c2.buf = m->top.c2.buf;
 
            /* transfer from-addr from top-level context buffer to instance */
            if (!floated)
            {
                c->c2.from = m->top.c2.from;
            }
        }
 
        if (BLEN(&c->c2.buf) > 0)
        {
            struct link_socket_info *lsi;
            const uint8_t *orig_buf;
 
            /* decrypt in instance context */
 
            lsi = &sock->info;
            orig_buf = c->c2.buf.data;
            if (process_incoming_link_part1(c, lsi, floated))
            {
                /* nonzero length means that we have a valid, decrypted packed */
                if (floated && c->c2.buf.len > 0)
                {
                    multi_process_float(m, m->pending, sock);
                }
 
                process_incoming_link_part2(c, lsi, orig_buf);
            }
 
            if (TUNNEL_TYPE(m->top.c1.tuntap) == DEV_TYPE_TUN)
            {
                /* extract packet source and dest addresses */
                mroute_flags =
                    mroute_extract_addr_from_packet(&src, &dest, 0, &c->c2.to_tun, DEV_TYPE_TUN);
 
                /* drop packet if extract failed */
                if (!(mroute_flags & MROUTE_EXTRACT_SUCCEEDED))
                {
                    c->c2.to_tun.len = 0;
                }
                /* make sure that source address is associated with this client */
                else if (multi_get_instance_by_virtual_addr(m, &src, true) != m->pending)
                {
                    /* IPv6 link-local address (fe80::xxx)? */
                    if ((src.type & MR_ADDR_MASK) == MR_ADDR_IPV6
                        && IN6_IS_ADDR_LINKLOCAL(&src.v6.addr))
                    {
                        /* do nothing, for now.  TODO: add address learning */
                    }
                    else
                    {
                        msg(D_MULTI_DROPPED,
                            "MULTI: bad source address from client [%s], packet dropped",
                            mroute_addr_print(&src, &gc));
                    }
                    c->c2.to_tun.len = 0;
                }
                /* client-to-client communication enabled? */
                else if (m->enable_c2c)
                {
                    /* multicast? */
                    if (mroute_flags & MROUTE_EXTRACT_MCAST)
                    {
                        /* for now, treat multicast as broadcast */
                        multi_bcast(m, &c->c2.to_tun, m->pending, 0);
                    }
                    else /* possible client to client routing */
                    {
                        ASSERT(!(mroute_flags & MROUTE_EXTRACT_BCAST));
                        mi = multi_get_instance_by_virtual_addr(m, &dest, true);
 
                        /* if dest addr is a known client, route to it */
                        if (mi)
                        {
                            {
                                multi_unicast(m, &c->c2.to_tun, mi);
                                register_activity(c, BLEN(&c->c2.to_tun));
                            }
                            c->c2.to_tun.len = 0;
                        }
                    }
                }
            }
            else if (TUNNEL_TYPE(m->top.c1.tuntap) == DEV_TYPE_TAP)
            {
                uint16_t vid = 0;
 
                if (m->top.options.vlan_tagging)
                {
                    if (vlan_is_tagged(&c->c2.to_tun))
                    {
                        /* Drop VLAN-tagged frame. */
                        msg(D_VLAN_DEBUG, "dropping incoming VLAN-tagged frame");
                        c->c2.to_tun.len = 0;
                    }
                    else
                    {
                        vid = c->options.vlan_pvid;
                    }
                }
                /* extract packet source and dest addresses */
                mroute_flags =
                    mroute_extract_addr_from_packet(&src, &dest, vid, &c->c2.to_tun, DEV_TYPE_TAP);
 
                if (mroute_flags & MROUTE_EXTRACT_SUCCEEDED)
                {
                    if (multi_learn_addr(m, m->pending, &src, 0) == m->pending)
                    {
                        /* check for broadcast */
                        if (m->enable_c2c)
                        {
                            if (mroute_flags & (MROUTE_EXTRACT_BCAST | MROUTE_EXTRACT_MCAST))
                            {
                                multi_bcast(m, &c->c2.to_tun, m->pending, vid);
                            }
                            else /* try client-to-client routing */
                            {
                                mi = multi_get_instance_by_virtual_addr(m, &dest, false);
 
                                /* if dest addr is a known client, route to it */
                                if (mi)
                                {
                                    multi_unicast(m, &c->c2.to_tun, mi);
                                    register_activity(c, BLEN(&c->c2.to_tun));
                                    c->c2.to_tun.len = 0;
                                }
                            }
                        }
                    }
                    else
                    {
                        msg(D_MULTI_DROPPED,
                            "MULTI: bad source address from client [%s], packet dropped",
                            mroute_addr_print(&src, &gc));
                        c->c2.to_tun.len = 0;
                    }
                }
                else
                {
                    c->c2.to_tun.len = 0;
                }
            }
        }
 
        /* postprocess and set wakeup */
        ret = multi_process_post(m, m->pending, mpp_flags);
 
        clear_prefix();
    }
 
    gc_free(&gc);
    return ret;
}
 
/*
 * Process packets in the TUN/TAP interface -> TCP/UDP socket direction,
 * i.e. server -> client direction.
 */
bool
multi_process_incoming_tun(struct multi_context *m, const unsigned int mpp_flags)
{
    bool ret = true;
 
    if (BLEN(&m->top.c2.buf) > 0)
    {
        unsigned int mroute_flags;
        struct mroute_addr src = { 0 }, dest = { 0 };
        const int dev_type = TUNNEL_TYPE(m->top.c1.tuntap);
        int16_t vid = 0;
 
#ifdef MULTI_DEBUG_EVENT_LOOP
        printf("TUN -> TCP/UDP [%d]\n", BLEN(&m->top.c2.buf));
#endif
 
        if (m->pending)
        {
            return true;
        }
 
        if (dev_type == DEV_TYPE_TAP && m->top.options.vlan_tagging)
        {
            vid = vlan_decapsulate(&m->top, &m->top.c2.buf);
            if (vid < 0)
            {
                return false;
            }
        }
 
        /*
         * Route an incoming tun/tap packet to
         * the appropriate multi_instance object.
         */
 
        mroute_flags = mroute_extract_addr_from_packet(&src, &dest, vid, &m->top.c2.buf, dev_type);
 
        if (mroute_flags & MROUTE_EXTRACT_SUCCEEDED)
        {
            struct context *c;
 
            /* broadcast or multicast dest addr? */
            if (mroute_flags & (MROUTE_EXTRACT_BCAST | MROUTE_EXTRACT_MCAST))
            {
                /* for now, treat multicast as broadcast */
                multi_bcast(m, &m->top.c2.buf, NULL, vid);
            }
            else
            {
                multi_set_pending(
                    m, multi_get_instance_by_virtual_addr(m, &dest, dev_type == DEV_TYPE_TUN));
 
                if (m->pending)
                {
                    /* get instance context */
                    c = &m->pending->context;
 
                    set_prefix(m->pending);
 
                    {
                        if (multi_output_queue_ready(m, m->pending))
                        {
                            /* transfer packet pointer from top-level context buffer to instance */
                            c->c2.buf = m->top.c2.buf;
                        }
                        else
                        {
                            /* drop packet */
                            msg(D_MULTI_DROPPED,
                                "MULTI: packet dropped due to output saturation (multi_process_incoming_tun)");
                            buf_reset_len(&c->c2.buf);
                        }
                    }
 
                    /* encrypt in instance context */
                    process_incoming_tun(c, c->c2.link_sockets[0]);
 
                    /* postprocess and set wakeup */
                    ret = multi_process_post(m, m->pending, mpp_flags);
 
                    clear_prefix();
                }
            }
        }
    }
    return ret;
}
 
/*
 * Process a possible client-to-client/bcast/mcast message in the
 * queue.
 */
struct multi_instance *
multi_get_queue(struct mbuf_set *ms)
{
    struct mbuf_item item;
 
    if (mbuf_extract_item(ms, &item)) /* cleartext IP packet */
    {
        unsigned int pip_flags = PIPV4_PASSTOS | PIPV6_ICMP_NOHOST_SERVER;
 
        set_prefix(item.instance);
        item.instance->context.c2.buf = item.buffer->buf;
        if (item.buffer->flags
            & MF_UNICAST) /* --mssfix doesn't make sense for broadcast or multicast */
        {
            pip_flags |= PIP_MSSFIX;
        }
        process_ip_header(&item.instance->context, pip_flags, &item.instance->context.c2.buf,
                          item.instance->context.c2.link_sockets[0]);
        encrypt_sign(&item.instance->context, true);
        mbuf_free_buf(item.buffer);
 
        dmsg(D_MULTI_DEBUG, "MULTI: C2C/MCAST/BCAST");
 
        clear_prefix();
        return item.instance;
    }
    else
    {
        return NULL;
    }
}
 
/*
 * Called when an I/O wait times out.  Usually means that a particular
 * client instance object needs timer-based service.
 */
bool
multi_process_timeout(struct multi_context *m, const unsigned int mpp_flags)
{
    bool ret = true;
 
#ifdef MULTI_DEBUG_EVENT_LOOP
    printf("%s -> TIMEOUT\n", id(m->earliest_wakeup));
#endif
 
    /* instance marked for wakeup? */
    if (m->earliest_wakeup)
    {
        if (m->earliest_wakeup == (struct multi_instance *)&m->deferred_shutdown_signal)
        {
            schedule_remove_entry(m->schedule,
                                  (struct schedule_entry *)&m->deferred_shutdown_signal);
            throw_signal(m->deferred_shutdown_signal.signal_received);
        }
        else
        {
            set_prefix(m->earliest_wakeup);
            ret = multi_process_post(m, m->earliest_wakeup, mpp_flags);
            clear_prefix();
        }
        m->earliest_wakeup = NULL;
    }
    return ret;
}
 
/*
 * Drop a TUN/TAP outgoing packet..
 */
void
multi_process_drop_outgoing_tun(struct multi_context *m, const unsigned int mpp_flags)
{
    struct multi_instance *mi = m->pending;
 
    ASSERT(mi);
 
    set_prefix(mi);
 
    msg(D_MULTI_ERRORS, "MULTI: Outgoing TUN queue full, dropped packet len=%d",
        mi->context.c2.to_tun.len);
 
    buf_reset(&mi->context.c2.to_tun);
 
    multi_process_post(m, mi, mpp_flags);
    clear_prefix();
}
 
/*
 * Per-client route quota management
 */
 
void
route_quota_exceeded(const struct multi_instance *mi)
{
    struct gc_arena gc = gc_new();
    msg(D_ROUTE_QUOTA,
        "MULTI ROUTE: route quota (%d) exceeded for %s (see --max-routes-per-client option)",
        mi->context.options.max_routes_per_client, multi_instance_string(mi, false, &gc));
    gc_free(&gc);
}
 
#ifdef ENABLE_DEBUG
/*
 * Flood clients with random packets
 */
static void
gremlin_flood_clients(struct multi_context *m)
{
    const int level = GREMLIN_PACKET_FLOOD_LEVEL(m->top.options.gremlin);
    if (level)
    {
        struct gc_arena gc = gc_new();
        struct buffer buf = alloc_buf_gc(BUF_SIZE(&m->top.c2.frame), &gc);
        struct packet_flood_parms parm = get_packet_flood_parms(level);
        int i;
 
        ASSERT(buf_init(&buf, m->top.c2.frame.buf.headroom));
        parm.packet_size = min_int(parm.packet_size, m->top.c2.frame.buf.payload_size);
 
        msg(D_GREMLIN, "GREMLIN_FLOOD_CLIENTS: flooding clients with %d packets of size %d",
            parm.n_packets, parm.packet_size);
 
        for (i = 0; i < parm.packet_size; ++i)
        {
            ASSERT(buf_write_u8(&buf, (uint8_t)(get_random() & 0xFF)));
        }
 
        for (i = 0; i < parm.n_packets; ++i)
        {
            multi_bcast(m, &buf, NULL, 0);
        }
 
        gc_free(&gc);
    }
}
#endif /* ifdef ENABLE_DEBUG */
 
static bool
stale_route_check_trigger(struct multi_context *m)
{
    struct timeval null;
    CLEAR(null);
    return event_timeout_trigger(&m->stale_routes_check_et, &null, ETT_DEFAULT);
}
 
/*
 * Process timers in the top-level context
 */
void
multi_process_per_second_timers_dowork(struct multi_context *m)
{
    /* possibly reap instances/routes in vhash */
    multi_reap_process(m);
 
    /* possibly print to status log */
    if (m->top.c1.status_output)
    {
        if (status_trigger(m->top.c1.status_output))
        {
            multi_print_status(m, m->top.c1.status_output, m->status_file_version);
        }
    }
 
    /* possibly flush ifconfig-pool file */
    multi_ifconfig_pool_persist(m, false);
 
#ifdef ENABLE_DEBUG
    gremlin_flood_clients(m);
#endif
 
    /* Should we check for stale routes? */
    if (m->top.options.stale_routes_check_interval && stale_route_check_trigger(m))
    {
        check_stale_routes(m);
    }
}
 
static void
multi_top_init(struct context *top)
{
    inherit_context_top(&top->multi->top, top);
    top->multi->top.c2.buffers = init_context_buffers(&top->c2.frame);
}
 
static void
multi_top_free(struct multi_context *m)
{
    close_context(&m->top, -1, CC_GC_FREE);
    free_context_buffers(m->top.c2.buffers);
}
 
static bool
is_exit_restart(int sig)
{
    return (sig == SIGUSR1 || sig == SIGTERM || sig == SIGHUP || sig == SIGINT);
}
 
static void
multi_push_restart_schedule_exit(struct multi_context *m, bool next_server)
{
    /* tell all clients to restart */
    for (uint32_t i = 0; i <= m->max_peerid; i++)
    {
        struct multi_instance *mi = m->instances[i];
        if (mi && !mi->halt && proto_is_dgram(mi->context.c2.link_sockets[0]->info.proto))
        {
            send_control_channel_string(&mi->context, next_server ? "RESTART,[N]" : "RESTART",
                                        D_PUSH);
            multi_schedule_context_wakeup(m, mi);
        }
    }
 
    /* reschedule signal */
    ASSERT(!openvpn_gettimeofday(&m->deferred_shutdown_signal.wakeup, NULL));
    struct timeval tv = { .tv_sec = 2, .tv_usec = 0 };
    tv_add(&m->deferred_shutdown_signal.wakeup, &tv);
 
    m->deferred_shutdown_signal.signal_received = m->top.sig->signal_received;
 
    schedule_add_entry(m->schedule, (struct schedule_entry *)&m->deferred_shutdown_signal,
                       &m->deferred_shutdown_signal.wakeup,
                       compute_wakeup_sigma(&tv));
 
    signal_reset(m->top.sig, 0);
}
 
/*
 * Return true if event loop should break,
 * false if it should continue.
 */
bool
multi_process_signal(struct multi_context *m)
{
    if (signal_reset(m->top.sig, SIGUSR2) == SIGUSR2)
    {
        struct status_output *so = status_open(NULL, 0, M_INFO, NULL, 0);
        multi_print_status(m, so, m->status_file_version);
        status_close(so);
        return false;
    }
    else if (has_udp_in_local_list(&m->top.options) && is_exit_restart(m->top.sig->signal_received)
             && (m->deferred_shutdown_signal.signal_received == 0)
             && m->top.options.ce.explicit_exit_notification != 0)
    {
        multi_push_restart_schedule_exit(m, m->top.options.ce.explicit_exit_notification == 2);
        return false;
    }
    return true;
}
 
/*
 * Management subsystem callbacks
 */
#ifdef ENABLE_MANAGEMENT
 
static void
management_callback_status(void *arg, const int version, struct status_output *so)
{
    struct multi_context *m = (struct multi_context *)arg;
 
    if (!version)
    {
        multi_print_status(m, so, m->status_file_version);
    }
    else
    {
        multi_print_status(m, so, version);
    }
}
 
static int
management_callback_n_clients(void *arg)
{
    struct multi_context *m = (struct multi_context *)arg;
    return m->n_clients;
}
 
static int
management_callback_kill_by_cn(void *arg, const char *del_cn)
{
    struct multi_context *m = (struct multi_context *)arg;
    int count = 0;
 
    for (uint32_t i = 0; i <= m->max_peerid; i++)
    {
        struct multi_instance *mi = m->instances[i];
        if (mi && !mi->halt)
        {
            const char *cn = tls_common_name(mi->context.c2.tls_multi, false);
            if (cn && !strcmp(cn, del_cn))
            {
                multi_signal_instance(m, mi, SIGTERM);
                ++count;
            }
        }
    }
    return count;
}
 
static int
management_callback_kill_by_addr(void *arg, const in_addr_t addr, const uint16_t port, const uint8_t proto)
{
    struct multi_context *m = (struct multi_context *)arg;
    struct openvpn_sockaddr saddr;
    struct mroute_addr maddr;
    int count = 0;
 
    CLEAR(saddr);
    saddr.addr.in4.sin_family = AF_INET;
    saddr.addr.in4.sin_addr.s_addr = htonl(addr);
    saddr.addr.in4.sin_port = htons(port);
    maddr.proto = proto;
    if (mroute_extract_openvpn_sockaddr(&maddr, &saddr, true))
    {
        for (uint32_t i = 0; i <= m->max_peerid; i++)
        {
            struct multi_instance *mi = m->instances[i];
            if (mi && !mi->halt && mroute_addr_equal(&maddr, &mi->real))
            {
                multi_signal_instance(m, mi, SIGTERM);
                ++count;
            }
        }
    }
    return count;
}
 
static void
management_delete_event(void *arg, event_t event)
{
    struct multi_context *m = (struct multi_context *)arg;
    if (m->multi_io)
    {
        multi_tcp_delete_event(m->multi_io, event);
    }
}
 
struct multi_instance *
lookup_by_cid(struct multi_context *m, const unsigned long cid)
{
    if (m)
    {
        struct multi_instance *mi = (struct multi_instance *)hash_lookup(m->cid_hash, &cid);
        if (mi && !mi->halt)
        {
            return mi;
        }
    }
    return NULL;
}
 
static bool
management_kill_by_cid(void *arg, const unsigned long cid, const char *kill_msg)
{
    struct multi_context *m = (struct multi_context *)arg;
    struct multi_instance *mi = lookup_by_cid(m, cid);
    if (mi)
    {
        send_restart(&mi->context, kill_msg); /* was: multi_signal_instance (m, mi, SIGTERM); */
        multi_schedule_context_wakeup(m, mi);
        return true;
    }
    else
    {
        return false;
    }
}
 
static bool
management_client_pending_auth(void *arg, const unsigned long cid, const unsigned int mda_key_id,
                               const char *extra, unsigned int timeout)
{
    struct multi_context *m = (struct multi_context *)arg;
    struct multi_instance *mi = lookup_by_cid(m, cid);
 
    if (mi)
    {
        struct tls_multi *multi = mi->context.c2.tls_multi;
        struct tls_session *session;
 
        if (multi->session[TM_INITIAL].key[KS_PRIMARY].mda_key_id == mda_key_id)
        {
            session = &multi->session[TM_INITIAL];
        }
        else if (multi->session[TM_ACTIVE].key[KS_PRIMARY].mda_key_id == mda_key_id)
        {
            session = &multi->session[TM_ACTIVE];
        }
        else
        {
            return false;
        }
 
        /* sends INFO_PRE and AUTH_PENDING messages to client */
        bool ret = send_auth_pending_messages(multi, session, extra, timeout);
        reschedule_multi_process(&mi->context);
        multi_schedule_context_wakeup(m, mi);
        return ret;
    }
    return false;
}
 
 
static bool
management_client_auth(void *arg, const unsigned long cid, const unsigned int mda_key_id,
                       const bool auth, const char *reason, const char *client_reason,
                       struct buffer_list *cc_config) /* ownership transferred */
{
    struct multi_context *m = (struct multi_context *)arg;
    struct multi_instance *mi = lookup_by_cid(m, cid);
    bool cc_config_owned = true;
    bool ret = false;
 
    if (mi)
    {
        ret = tls_authenticate_key(mi->context.c2.tls_multi, mda_key_id, auth, client_reason);
        if (ret)
        {
            if (auth)
            {
                if (mi->context.c2.tls_multi->multi_state <= CAS_WAITING_AUTH)
                {
                    set_cc_config(mi, cc_config);
                    cc_config_owned = false;
                }
            }
            else if (reason)
            {
                msg(D_MULTI_LOW, "MULTI: connection rejected: %s, CLI:%s", reason,
                    np(client_reason));
            }
        }
    }
    if (cc_config_owned && cc_config)
    {
        buffer_list_free(cc_config);
    }
    return ret;
}
 
static char *
management_get_peer_info(void *arg, const unsigned long cid)
{
    struct multi_context *m = (struct multi_context *)arg;
    struct multi_instance *mi = lookup_by_cid(m, cid);
    char *ret = NULL;
 
    if (mi)
    {
        ret = mi->context.c2.tls_multi->peer_info;
    }
 
    return ret;
}
 
#endif /* ifdef ENABLE_MANAGEMENT */
 
 
void
init_management_callback_multi(struct multi_context *m)
{
#ifdef ENABLE_MANAGEMENT
    if (management)
    {
        struct management_callback cb;
        CLEAR(cb);
        cb.arg = m;
        cb.flags = MCF_SERVER;
        cb.status = management_callback_status;
        cb.show_net = management_show_net_callback;
        cb.kill_by_cn = management_callback_kill_by_cn;
        cb.kill_by_addr = management_callback_kill_by_addr;
        cb.delete_event = management_delete_event;
        cb.n_clients = management_callback_n_clients;
        cb.kill_by_cid = management_kill_by_cid;
        cb.client_auth = management_client_auth;
        cb.client_pending_auth = management_client_pending_auth;
        cb.get_peer_info = management_get_peer_info;
        cb.push_update_broadcast = management_callback_send_push_update_broadcast;
        cb.push_update_by_cid = management_callback_send_push_update_by_cid;
        management_set_callback(management, &cb);
    }
#endif /* ifdef ENABLE_MANAGEMENT */
}
 
void
multi_assign_peer_id(struct multi_context *m, struct multi_instance *mi)
{
    /* max_clients must be less then max peer-id value */
    ASSERT(m->max_clients < MAX_PEER_ID);
 
    for (uint32_t i = 0; i < m->max_clients; ++i)
    {
        if (!m->instances[i])
        {
            mi->context.c2.tls_multi->peer_id = i;
            m->instances[i] = mi;
            break;
        }
    }
 
    /* should not really end up here, since multi_create_instance returns null
     * if amount of clients exceeds max_clients and this method would then
     * also not have been called */
    ASSERT(mi->context.c2.tls_multi->peer_id < m->max_clients);
 
    if (mi->context.c2.tls_multi->peer_id > m->max_peerid)
    {
        m->max_peerid = mi->context.c2.tls_multi->peer_id;
    }
}
 
static void
multi_get_timeout(struct multi_context *multi, struct timeval *timeval)
{
    multi_get_timeout_instance(multi, timeval);
 
#ifdef ENABLE_MANAGEMENT
    if (management)
    {
        management_check_bytecount_server(multi, timeval);
    }
#endif /* ENABLE_MANAGEMENT */
}
 
/**************************************************************************/
static void
tunnel_server_loop(struct multi_context *multi)
{
    int status;
 
    while (true)
    {
        /* wait on tun/socket list */
        multi_get_timeout(multi, &multi->top.c2.timeval);
        status = multi_io_wait(multi);
        MULTI_CHECK_SIG(multi);
 
        /* check on status of coarse timers */
        multi_process_per_second_timers(multi);
 
        /* timeout? */
        if (status > 0)
        {
            /* process the I/O which triggered select */
            multi_io_process_io(multi);
        }
        else if (status == 0)
        {
            multi_io_action(multi, NULL, TA_TIMEOUT, false);
        }
 
        MULTI_CHECK_SIG(multi);
    }
}
 
/*
 * Top level event loop.
 */
void
tunnel_server(struct context *top)
{
    ASSERT(top->options.mode == MODE_SERVER);
 
    struct multi_context multi;
 
    top->mode = CM_TOP;
    top->multi = &multi;
    context_clear_2(top);
 
    /* initialize top-tunnel instance */
    init_instance_handle_signals(top, top->es, CC_HARD_USR1_TO_HUP);
    if (IS_SIG(top))
    {
        return;
    }
 
    /* initialize global multi_context object */
    multi_init(top);
 
    /* initialize our cloned top object */
    multi_top_init(top);
 
    /* initialize management interface */
    init_management_callback_multi(&multi);
 
    /* finished with initialization */
    initialization_sequence_completed(top, ISC_SERVER); /* --mode server --proto tcp-server */
 
#ifdef ENABLE_ASYNC_PUSH
    multi.top.c2.inotify_fd = inotify_init();
    if (multi.top.c2.inotify_fd < 0)
    {
        msg(D_MULTI_ERRORS | M_ERRNO, "MULTI: inotify_init error");
    }
#endif
 
    tunnel_server_loop(&multi);
 
#ifdef ENABLE_ASYNC_PUSH
    msg(D_LOW, "%s: close multi.top.c2.inotify_fd (%d)",
        __func__, multi.top.c2.inotify_fd);
    close(multi.top.c2.inotify_fd);
#endif
 
    /* shut down management interface */
    uninit_management_callback();
 
    /* save ifconfig-pool */
    multi_ifconfig_pool_persist(&multi, true);
 
    /* tear down tunnel instance (unless --persist-tun) */
    multi_uninit(&multi);
    multi_top_free(&multi);
    close_instance(top);
}
 
/* Searches for the address and deletes it if it is owned by the multi_instance */
static void
multi_unlearn_addr(struct multi_context *m, struct multi_instance *mi, const struct mroute_addr *addr)
{
    struct hash_element *he;
    const uint32_t hv = hash_value(m->vhash, addr);
    struct hash_bucket *bucket = hash_bucket(m->vhash, hv);
    struct multi_route *r = NULL;
 
    /* if route currently exists, get the instance which owns it */
    he = hash_lookup_fast(m->vhash, bucket, addr, hv);
    if (he)
    {
        r = (struct multi_route *)he->value;
    }
 
    /* if the route does not exist or exists but is not owned by the current instance, return */
    if (!r || r->instance != mi)
    {
        return;
    }
 
    struct gc_arena gc = gc_new();
    msg(D_MULTI_LOW, "MULTI: Unlearn: %s -> %s", mroute_addr_print(&r->addr, &gc), multi_instance_string(mi, false, &gc));
    learn_address_script(m, NULL, "delete", &r->addr);
    hash_remove_by_value(m->vhash, r);
    multi_route_del(r);
 
    gc_free(&gc);
}
 
static void
multi_unlearn_in_addr_t(struct multi_context *m, struct multi_instance *mi, in_addr_t a)
{
    struct mroute_addr addr;
    CLEAR(addr);
 
    addr.type = MR_ADDR_IPV4;
    addr.len = 4;
    addr.v4.addr = a;
 
    multi_unlearn_addr(m, mi, &addr);
}
 
static void
multi_unlearn_in6_addr(struct multi_context *m, struct multi_instance *mi, struct in6_addr a6)
{
    struct mroute_addr addr;
    CLEAR(addr);
 
    addr.type = MR_ADDR_IPV6;
    addr.len = 16;
    addr.v6.addr = a6;
 
    multi_unlearn_addr(m, mi, &addr);
}
 
/* Function to unlearn previous ifconfig of a client in the server multi_context after a PUSH_UPDATE */
void
unlearn_ifconfig(struct multi_context *m, struct multi_instance *mi)
{
    in_addr_t old_addr = 0;
    old_addr = htonl(mi->context.c2.push_ifconfig_local);
    multi_unlearn_in_addr_t(m, mi, old_addr);
    mi->context.c2.push_ifconfig_defined = false;
    mi->context.c2.push_ifconfig_local = 0;
    mi->reporting_addr = 0;
}
 
/* Function to unlearn previous ifconfig-ipv6 of a client in the server multi_context after a PUSH_UPDATE */
void
unlearn_ifconfig_ipv6(struct multi_context *m, struct multi_instance *mi)
{
    struct in6_addr old_addr6;
    CLEAR(old_addr6);
    old_addr6 = mi->context.c2.push_ifconfig_ipv6_local;
    multi_unlearn_in6_addr(m, mi, old_addr6);
    mi->context.c2.push_ifconfig_ipv6_defined = false;
    CLEAR(mi->context.c2.push_ifconfig_ipv6_local);
    CLEAR(mi->reporting_addr_ipv6);
}
 
void
update_vhash(struct multi_context *m, struct multi_instance *mi, const char *new_ip, const char *new_ipv6)
{
    if (new_ip)
    {
        /* Remove old IP */
        if (mi->context.c2.push_ifconfig_defined)
        {
            unlearn_ifconfig(m, mi);
        }
 
        /* Add new IP */
        struct in_addr new_addr;
        CLEAR(new_addr);
        if (inet_pton(AF_INET, new_ip, &new_addr) == 1
            && multi_learn_in_addr_t(m, mi, ntohl(new_addr.s_addr), -1, true))
        {
            mi->context.c2.push_ifconfig_defined = true;
            mi->context.c2.push_ifconfig_local = ntohl(new_addr.s_addr);
            /* set our client's VPN endpoint for status reporting purposes */
            mi->reporting_addr = mi->context.c2.push_ifconfig_local;
        }
    }
 
    if (new_ipv6)
    {
        /* Remove old IPv6 */
        if (mi->context.c2.push_ifconfig_ipv6_defined)
        {
            unlearn_ifconfig_ipv6(m, mi);
        }
 
        /* Add new IPv6 */
        struct in6_addr new_addr6;
        CLEAR(new_addr6);
        if (inet_pton(AF_INET6, new_ipv6, &new_addr6) == 1
            && multi_learn_in6_addr(m, mi, new_addr6, -1, true))
        {
            mi->context.c2.push_ifconfig_ipv6_defined = true;
            mi->context.c2.push_ifconfig_ipv6_local = new_addr6;
            /* set our client's VPN endpoint for status reporting purposes */
            mi->reporting_addr_ipv6 = mi->context.c2.push_ifconfig_ipv6_local;
        }
    }
}
 
bool
multi_check_push_ifconfig_extra_route(struct multi_instance *mi, in_addr_t dest)
{
    struct options *o = &mi->context.options;
    in_addr_t local_addr, local_netmask;
 
    if (!o->ifconfig_local || !o->ifconfig_remote_netmask)
    {
        /* If we do not have a local address, we just return false as
         * this check doesn't make sense. */
        return false;
    }
 
    /* if it falls into the network defined by ifconfig_local we assume
     * it is already known to DCO and only install "extra" iroutes  */
    inet_pton(AF_INET, o->ifconfig_local, &local_addr);
    inet_pton(AF_INET, o->ifconfig_remote_netmask, &local_netmask);
 
    return (local_addr & local_netmask) != (dest & local_netmask);
}
 
bool
multi_check_push_ifconfig_ipv6_extra_route(struct multi_instance *mi,
                                           struct in6_addr *dest)
{
    struct options *o = &mi->context.options;
 
    if (!o->ifconfig_ipv6_local || !o->ifconfig_ipv6_netbits)
    {
        /* If we do not have a local address, we just return false as
         * this check doesn't make sense. */
        return false;
    }
 
    /* if it falls into the network defined by ifconfig_local we assume
     * it is already known to DCO and only install "extra" iroutes  */
    struct in6_addr ifconfig_local;
    if (inet_pton(AF_INET6, o->ifconfig_ipv6_local, &ifconfig_local) != 1)
    {
        return false;
    }
 
    return (!ipv6_net_contains_host(&ifconfig_local, o->ifconfig_ipv6_netbits,
                                    dest));
}