freebsd-skq/sys/netinet/tcp_syncache.h
Michael Tuexen 9e644c2300 tcp: add support for TCP over UDP
Adding support for TCP over UDP allows communication with
TCP stacks which can be implemented in userspace without
requiring special priviledges or specific support by the OS.
This is joint work with rrs.

Reviewed by:		rrs
Sponsored by:		Netflix, Inc.
MFC after:		1 week
Differential Revision:	https://reviews.freebsd.org/D29469
2021-04-18 16:16:42 +02:00

155 lines
5.3 KiB
C

/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 1982, 1986, 1993, 1994, 1995
* The Regents of the University of California. 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, 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.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
*
* @(#)tcp_var.h 8.4 (Berkeley) 5/24/95
* $FreeBSD$
*/
#ifndef _NETINET_TCP_SYNCACHE_H_
#define _NETINET_TCP_SYNCACHE_H_
#ifdef _KERNEL
void syncache_init(void);
#ifdef VIMAGE
void syncache_destroy(void);
#endif
void syncache_unreach(struct in_conninfo *, tcp_seq, uint16_t);
int syncache_expand(struct in_conninfo *, struct tcpopt *,
struct tcphdr *, struct socket **, struct mbuf *, uint16_t);
struct socket * syncache_add(struct in_conninfo *, struct tcpopt *,
struct tcphdr *, struct inpcb *, struct socket *, struct mbuf *,
void *, void *, uint8_t, uint16_t);
void syncache_chkrst(struct in_conninfo *, struct tcphdr *, struct mbuf *,
uint16_t);
void syncache_badack(struct in_conninfo *, uint16_t);
int syncache_pcblist(struct sysctl_req *);
struct syncache {
TAILQ_ENTRY(syncache) sc_hash;
struct in_conninfo sc_inc; /* addresses */
int sc_rxttime; /* retransmit time */
u_int16_t sc_rxmits; /* retransmit counter */
u_int16_t sc_port; /* remote UDP encaps port */
u_int32_t sc_tsreflect; /* timestamp to reflect */
u_int32_t sc_tsoff; /* ts offset w/ syncookies */
u_int32_t sc_flowlabel; /* IPv6 flowlabel */
tcp_seq sc_irs; /* seq from peer */
tcp_seq sc_iss; /* our ISS */
struct mbuf *sc_ipopts; /* source route */
u_int16_t sc_peer_mss; /* peer's MSS */
u_int16_t sc_wnd; /* advertised window */
u_int8_t sc_ip_ttl; /* TTL / Hop Limit */
u_int8_t sc_ip_tos; /* TOS / Traffic Class */
u_int8_t sc_requested_s_scale:4,
sc_requested_r_scale:4;
u_int16_t sc_flags;
#if defined(TCP_OFFLOAD) || !defined(TCP_OFFLOAD_DISABLE)
struct toedev *sc_tod; /* entry added by this TOE */
void *sc_todctx; /* TOE driver context */
#endif
struct label *sc_label; /* MAC label reference */
struct ucred *sc_cred; /* cred cache for jail checks */
void *sc_tfo_cookie; /* for TCP Fast Open response */
void *sc_pspare; /* TCP_SIGNATURE */
u_int32_t sc_spare[2]; /* UTO */
};
/*
* Flags for the sc_flags field.
*/
#define SCF_NOOPT 0x01 /* no TCP options */
#define SCF_WINSCALE 0x02 /* negotiated window scaling */
#define SCF_TIMESTAMP 0x04 /* negotiated timestamps */
/* MSS is implicit */
#define SCF_UNREACH 0x10 /* icmp unreachable received */
#define SCF_SIGNATURE 0x20 /* send MD5 digests */
#define SCF_SACK 0x80 /* send SACK option */
#define SCF_ECN 0x100 /* send ECN setup packet */
#define SCF_ACE_N 0x200 /* send ACE non-ECT setup */
#define SCF_ACE_0 0x400 /* send ACE ECT0 setup */
#define SCF_ACE_1 0x800 /* send ACE ECT1 setup */
#define SCF_ACE_CE 0x1000 /* send ACE CE setup */
struct syncache_head {
struct mtx sch_mtx;
TAILQ_HEAD(sch_head, syncache) sch_bucket;
struct callout sch_timer;
int sch_nextc;
u_int sch_length;
struct tcp_syncache *sch_sc;
time_t sch_last_overflow;
};
#define SYNCOOKIE_SECRET_SIZE 16
#define SYNCOOKIE_LIFETIME 15 /* seconds */
struct syncookie_secret {
volatile u_int oddeven;
uint8_t key[2][SYNCOOKIE_SECRET_SIZE];
struct callout reseed;
u_int lifetime;
};
#define TCP_SYNCACHE_PAUSE_TIME SYNCOOKIE_LIFETIME
#define TCP_SYNCACHE_MAX_BACKOFF 6 /* 16 minutes */
struct tcp_syncache {
struct syncache_head *hashbase;
uma_zone_t zone;
u_int hashsize;
u_int hashmask;
u_int bucket_limit;
u_int cache_limit;
u_int rexmt_limit;
uint32_t hash_secret;
struct vnet *vnet;
struct syncookie_secret secret;
struct mtx pause_mtx;
struct callout pause_co;
time_t pause_until;
uint8_t pause_backoff;
volatile bool paused;
bool see_other;
};
/* Internal use for the syncookie functions. */
union syncookie {
uint8_t cookie;
struct {
uint8_t odd_even:1,
sack_ok:1,
wscale_idx:3,
mss_idx:3;
} flags;
};
#endif /* _KERNEL */
#endif /* !_NETINET_TCP_SYNCACHE_H_ */