mss.c File Reference

#include "syshead.h"
#include "error.h"
#include "mss.h"
#include "crypto.h"
#include "ssl_common.h"
#include "memdbg.h"
#include "forward.h"

Include dependency graph for mss.c:

Go to the source code of this file.

Functions
void	mss_fixup_ipv4 (struct buffer *buf, uint16_t maxmss)
void	mss_fixup_ipv6 (struct buffer *buf, uint16_t maxmss)
void	mss_fixup_dowork (struct buffer *buf, uint16_t maxmss)
static size_t	adjust_payload_max_cbc (const struct key_type *kt, size_t target)
static size_t	get_ip_encap_overhead (const struct options *options, const struct link_socket_info *lsi)
static void	frame_calculate_fragment (struct frame *frame, const struct key_type *kt, const struct options *options, const struct link_socket_info *lsi)
static void	frame_calculate_mssfix (struct frame *frame, const struct key_type *kt, const struct options *options, const struct link_socket_info *lsi)
void	frame_calculate_dynamic (struct frame *frame, const struct key_type *kt, const struct options *options, const struct link_socket_info *lsi)
	Set the –mssfix option.
void	frame_adjust_path_mtu (struct context *c)
	Checks and adjusts the fragment and mssfix value according to the discovered path mtu value.

Function Documentation

adjust_payload_max_cbc()

size_t adjust_payload_max_cbc ( const struct key_type * kt, size_t target )

inlinestatic

Definition at line 198 of file mss.c.

References key_type::cipher, cipher_kt_block_size(), cipher_kt_mode_cbc(), and round_down_size().

Referenced by frame_calculate_fragment(), and frame_calculate_mssfix().

frame_adjust_path_mtu()

void frame_adjust_path_mtu

(

struct context *

c

)

Checks and adjusts the fragment and mssfix value according to the discovered path mtu value.

Parameters

c	context to adjust

Definition at line 336 of file mss.c.

References link_socket_addr::actual, openvpn_sockaddr::addr, context::c1, context::c2, options::ce, D_MTU_INFO, datagram_overhead(), link_socket_actual::dest, connection_entry::fragment, connection_entry::fragment_encap, context_2::frame, frame_calculate_dynamic(), context_2::frame_fragment, get_link_socket_info(), key_schedule::key_type, context_1::ks, context_2::link_sockets, link_socket_info::lsa, msg, connection_entry::mssfix, connection_entry::mssfix_encap, link_socket::mtu, context::options, link_socket_info::proto, and openvpn_sockaddr::sa.

Referenced by check_fragment().

frame_calculate_dynamic()

void frame_calculate_dynamic	(	struct frame *	frame,
		const struct key_type *	kt,
		const struct options *	options,
		const struct link_socket_info *	lsi )

Set the –mssfix option.

Definition at line 317 of file mss.c.

References options::ce, connection_entry::fragment, frame_calculate_fragment(), frame_calculate_mssfix(), and connection_entry::mssfix.

Referenced by do_init_fragment(), frame_adjust_path_mtu(), init_instance(), test_mssfix_mtu_calculation(), and tls_session_update_crypto_params_do_work().

frame_calculate_fragment()

void frame_calculate_fragment ( struct frame * frame, const struct key_type * kt, const struct options * options, const struct link_socket_info * lsi )

static

Definition at line 242 of file mss.c.

References adjust_payload_max_cbc(), calc_packet_id_size_dc(), options::ce, key_type::cipher, cipher_kt_mode_cbc(), clamp_size_to_int(), connection_entry::fragment, connection_entry::fragment_encap, frame_calculate_protocol_header_size(), get_ip_encap_overhead(), and frame::max_fragment_size.

Referenced by frame_calculate_dynamic().

frame_calculate_mssfix()

void frame_calculate_mssfix ( struct frame * frame, const struct key_type * kt, const struct options * options, const struct link_socket_info * lsi )

static

Definition at line 272 of file mss.c.

References adjust_payload_max_cbc(), options::ce, frame::extra_tun, frame_calculate_payload_overhead(), frame_calculate_protocol_header_size(), get_ip_encap_overhead(), frame::mss_fix, connection_entry::mssfix, connection_entry::mssfix_encap, and connection_entry::mssfix_fixed.

Referenced by frame_calculate_dynamic().

get_ip_encap_overhead()

size_t get_ip_encap_overhead ( const struct options * options, const struct link_socket_info * lsi )

static

Definition at line 218 of file mss.c.

References link_socket_addr::actual, openvpn_sockaddr::addr, connection_entry::af, options::ce, datagram_overhead(), link_socket_actual::dest, link_socket_info::lsa, connection_entry::proto, link_socket_info::proto, and openvpn_sockaddr::sa.

Referenced by frame_calculate_fragment(), and frame_calculate_mssfix().

mss_fixup_dowork()

void mss_fixup_dowork	(	struct buffer *	buf,
		uint16_t	maxmss )

Definition at line 139 of file mss.c.

References ADJUST_CHECKSUM, BLEN, BLENZ, BPTR, openvpn_tcphdr::check, D_MSS, dmsg, openvpn_tcphdr::doff_res, OPENVPN_TCPH_GET_DOFF, OPENVPN_TCPOLEN_MAXSEG, OPENVPN_TCPOPT_EOL, OPENVPN_TCPOPT_MAXSEG, OPENVPN_TCPOPT_NOP, and verify_align_4.

Referenced by mss_fixup_ipv4(), and mss_fixup_ipv6().

mss_fixup_ipv4()

void mss_fixup_ipv4	(	struct buffer *	buf,
		uint16_t	maxmss )

Definition at line 46 of file mss.c.

References BLEN, BLENZ, BPTR, buf_advance(), openvpn_tcphdr::flags, openvpn_iphdr::frag_off, mss_fixup_dowork(), OPENVPN_IP_OFFMASK, OPENVPN_IPH_GET_LEN, OPENVPN_IPPROTO_TCP, OPENVPN_TCPH_SYN_MASK, openvpn_iphdr::protocol, openvpn_iphdr::tot_len, verify_align_4, and openvpn_iphdr::version_len.

Referenced by process_ip_header().

mss_fixup_ipv6()

void mss_fixup_ipv6	(	struct buffer *	buf,
		uint16_t	maxmss )

Definition at line 83 of file mss.c.

References BLEN, BLENZ, BPTR, buf_advance(), openvpn_tcphdr::flags, mss_fixup_dowork(), openvpn_ipv6hdr::nexthdr, OPENVPN_IPPROTO_TCP, OPENVPN_TCPH_SYN_MASK, openvpn_ipv6hdr::payload_len, and verify_align_4.

Referenced by process_ip_header().