freebsd-skq/sys/netgraph/ng_tcpmss.h
glebius 5e328f779e Add ng_tcpmss node, which alters MSS options of TCP packets. Useful to
hack MSS of packets outgoing via interface with small MTU, to workaround
path MTU discovery problems.

Written by Alexey Popov, with some cleanups from me. There are also plans
to improve mpd port, so that it uses this node, instead of doing MSS
hacking in userland, when 'enable tcpmssfix' option is on.

Submitted by:   Alexey Popov <lollypop@flexuser.ru>
2005-06-10 08:02:34 +00:00

83 lines
2.7 KiB
C

/*-
* ng_tcpmss.h
*
* Copyright (c) 2004, Alexey Popov <lollypop@flexuser.ru>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice unmodified, this list of conditions, and the following
* disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef _NETGRAPH_TCPMSS_H_
#define _NETGRAPH_TCPMSS_H_
/* Node type name and magic cookie */
#define NG_TCPMSS_NODE_TYPE "tcpmss"
#define NGM_TCPMSS_COOKIE 1097623478
/* Statistics structure for one hook. */
struct ng_tcpmss_hookstat {
uint64_t Octets;
uint64_t Packets;
uint16_t maxMSS;
uint64_t SYNPkts;
uint64_t FixedPkts;
};
/* Keep this in sync with the above structure definition. */
#define NG_TCPMSS_HOOKSTAT_INFO { \
{ "Octets", &ng_parse_uint64_type }, \
{ "Packets", &ng_parse_uint64_type }, \
{ "maxMSS", &ng_parse_uint16_type }, \
{ "SYNPkts", &ng_parse_uint64_type }, \
{ "FixedPkts", &ng_parse_uint64_type }, \
{ NULL } \
}
/* Structure for NGM_TCPMSS_CONFIG. */
struct ng_tcpmss_config {
char inHook[NG_HOOKSIZ];
char outHook[NG_HOOKSIZ];
uint16_t maxMSS;
};
/* Keep this in sync with the above structure definition. */
#define NG_TCPMSS_CONFIG_INFO { \
{ "inHook", &ng_parse_hookbuf_type }, \
{ "outHook", &ng_parse_hookbuf_type }, \
{ "maxMSS", &ng_parse_uint16_type }, \
{ NULL } \
}
/* Netgraph commands */
enum {
NGM_TCPMSS_GET_STATS = 1, /* Get stats. */
NGM_TCPMSS_CLR_STATS, /* Clear stats. */
NGM_TCPMSS_GETCLR_STATS, /* "Atomically" get and clear stats. */
NGM_TCPMSS_CONFIG /* Set configuration. */
};
#endif /* _NETGRAPH_TCPMSS_H_ */