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freebsd/sys/net/if_gre.h
Andrey V. Elsukov aee793eec9 Add GRE-in-UDP encapsulation support as defined in RFC8086. 
This GRE-in-UDP encapsulation allows the UDP source port field to be
used as an entropy field for load-balancing of GRE traffic in transit
networks. Also most of multiqueue network cards are able distribute
incoming UDP datagrams to different NIC queues, while very little are
able do this for GRE packets.

When an administrator enables UDP encapsulation with command
`ifconfig gre0 udpencap`, the driver creates kernel socket, that binds
to tunnel source address and after udp_set_kernel_tunneling() starts
receiving of all UDP packets destined to 4754 port. Each kernel socket
maintains list of tunnels with different destination addresses. Thus
when several tunnels use the same source address, they all handled by
single socket.  The IP[V6]_BINDANY socket option is used to be able bind
socket to source address even if it is not yet available in the system.
This may happen on system boot, when gre(4) interface is created before
source address become available. The encapsulation and sending of packets
is done directly from gre(4) into ip[6]_output() without using sockets.

Reviewed by:	eugen
MFC after:	1 month
Relnotes:	yes
Differential Revision:	https://reviews.freebsd.org/D19921
2019-04-24 09:05:45 +00:00

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5.7 KiB
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/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 1998 The NetBSD Foundation, Inc.
* Copyright (c) 2014 Andrey V. Elsukov <ae@FreeBSD.org>
* All rights reserved
*
* This code is derived from software contributed to The NetBSD Foundation
* by Heiko W.Rupp <hwr@pilhuhn.de>
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
*
* $NetBSD: if_gre.h,v 1.13 2003/11/10 08:51:52 wiz Exp $
* $FreeBSD$
*/
#ifndef _NET_IF_GRE_H_
#define _NET_IF_GRE_H_
#ifdef _KERNEL
/* GRE header according to RFC 2784 and RFC 2890 */
struct grehdr {
uint16_t gre_flags; /* GRE flags */
#define GRE_FLAGS_CP 0x8000 /* checksum present */
#define GRE_FLAGS_KP 0x2000 /* key present */
#define GRE_FLAGS_SP 0x1000 /* sequence present */
#define GRE_FLAGS_MASK (GRE_FLAGS_CP|GRE_FLAGS_KP|GRE_FLAGS_SP)
uint16_t gre_proto; /* protocol type */
uint32_t gre_opts[0]; /* optional fields */
} __packed;
#ifdef INET
struct greip {
struct ip gi_ip;
struct grehdr gi_gre;
} __packed;
struct greudp {
struct ip gi_ip;
struct udphdr gi_udp;
struct grehdr gi_gre;
} __packed;
#endif /* INET */
#ifdef INET6
struct greip6 {
struct ip6_hdr gi6_ip6;
struct grehdr gi6_gre;
} __packed;
struct greudp6 {
struct ip6_hdr gi6_ip6;
struct udphdr gi6_udp;
struct grehdr gi6_gre;
} __packed;
#endif /* INET6 */
CK_LIST_HEAD(gre_list, gre_softc);
CK_LIST_HEAD(gre_sockets, gre_socket);
struct gre_socket {
struct socket *so;
struct gre_list list;
CK_LIST_ENTRY(gre_socket) chain;
struct epoch_context epoch_ctx;
};
struct gre_softc {
struct ifnet *gre_ifp;
int gre_family; /* AF of delivery header */
uint32_t gre_iseq;
uint32_t gre_oseq;
uint32_t gre_key;
uint32_t gre_options;
uint32_t gre_csumflags;
uint32_t gre_port;
u_int gre_fibnum;
u_int gre_hlen; /* header size */
union {
void *hdr;
#ifdef INET
struct greip *iphdr;
struct greudp *udphdr;
#endif
#ifdef INET6
struct greip6 *ip6hdr;
struct greudp6 *udp6hdr;
#endif
} gre_uhdr;
struct gre_socket *gre_so;
CK_LIST_ENTRY(gre_softc) chain;
CK_LIST_ENTRY(gre_softc) srchash;
};
MALLOC_DECLARE(M_GRE);
#ifndef GRE_HASH_SIZE
#define GRE_HASH_SIZE (1 << 4)
#endif
#define GRE2IFP(sc) ((sc)->gre_ifp)
#define GRE_RLOCK_TRACKER struct epoch_tracker gre_et
#define GRE_RLOCK() epoch_enter_preempt(net_epoch_preempt, &gre_et)
#define GRE_RUNLOCK() epoch_exit_preempt(net_epoch_preempt, &gre_et)
#define GRE_WAIT() epoch_wait_preempt(net_epoch_preempt)
#define gre_hdr gre_uhdr.hdr
#define gre_iphdr gre_uhdr.iphdr
#define gre_ip6hdr gre_uhdr.ip6hdr
#define gre_udphdr gre_uhdr.udphdr
#define gre_udp6hdr gre_uhdr.udp6hdr
#define gre_oip gre_iphdr->gi_ip
#define gre_udp gre_udphdr->gi_udp
#define gre_oip6 gre_ip6hdr->gi6_ip6
#define gre_udp6 gre_udp6hdr->gi6_udp
struct gre_list *gre_hashinit(void);
void gre_hashdestroy(struct gre_list *);
int gre_input(struct mbuf *, int, int, void *);
void gre_update_hdr(struct gre_softc *, struct grehdr *);
void gre_update_udphdr(struct gre_softc *, struct udphdr *, uint16_t);
void gre_sofree(epoch_context_t);
void in_gre_init(void);
void in_gre_uninit(void);
int in_gre_setopts(struct gre_softc *, u_long, uint32_t);
int in_gre_ioctl(struct gre_softc *, u_long, caddr_t);
int in_gre_output(struct mbuf *, int, int);
void in6_gre_init(void);
void in6_gre_uninit(void);
int in6_gre_setopts(struct gre_softc *, u_long, uint32_t);
int in6_gre_ioctl(struct gre_softc *, u_long, caddr_t);
int in6_gre_output(struct mbuf *, int, int, uint32_t);
/*
* CISCO uses special type for GRE tunnel created as part of WCCP
* connection, while in fact those packets are just IPv4 encapsulated
* into GRE.
*/
#define ETHERTYPE_WCCP 0x883E
#endif /* _KERNEL */
#define GRESADDRS _IOW('i', 101, struct ifreq)
#define GRESADDRD _IOW('i', 102, struct ifreq)
#define GREGADDRS _IOWR('i', 103, struct ifreq)
#define GREGADDRD _IOWR('i', 104, struct ifreq)
#define GRESPROTO _IOW('i' , 105, struct ifreq)
#define GREGPROTO _IOWR('i', 106, struct ifreq)
#define GREGKEY _IOWR('i', 107, struct ifreq)
#define GRESKEY _IOW('i', 108, struct ifreq)
#define GREGOPTS _IOWR('i', 109, struct ifreq)
#define GRESOPTS _IOW('i', 110, struct ifreq)
#define GREGPORT _IOWR('i', 111, struct ifreq)
#define GRESPORT _IOW('i', 112, struct ifreq)
/* GRE-in-UDP encapsulation destination port as defined in RFC8086 */
#define GRE_UDPPORT 4754
#define GRE_ENABLE_CSUM 0x0001
#define GRE_ENABLE_SEQ 0x0002
#define GRE_UDPENCAP 0x0004
#define GRE_OPTMASK (GRE_ENABLE_CSUM|GRE_ENABLE_SEQ|GRE_UDPENCAP)
#endif /* _NET_IF_GRE_H_ */
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