HardenedBSD/sbin/ifconfig/ifgre.c
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

145 lines
3.8 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2008 Andrew Thompson. 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 HIS RELATIVES 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 MIND, 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <net/if.h>
#include <net/if_gre.h>
#include <ctype.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <err.h>
#include "ifconfig.h"
#define GREBITS "\020\01ENABLE_CSUM\02ENABLE_SEQ\03UDPENCAP"
static void gre_status(int s);
static void
gre_status(int s)
{
uint32_t opts, port;
opts = 0;
ifr.ifr_data = (caddr_t)&opts;
if (ioctl(s, GREGKEY, &ifr) == 0)
if (opts != 0)
printf("\tgrekey: 0x%x (%u)\n", opts, opts);
opts = 0;
if (ioctl(s, GREGOPTS, &ifr) != 0 || opts == 0)
return;
port = 0;
ifr.ifr_data = (caddr_t)&port;
if (ioctl(s, GREGPORT, &ifr) == 0 && port != 0)
printf("\tudpport: %u\n", port);
printb("\toptions", opts, GREBITS);
putchar('\n');
}
static void
setifgrekey(const char *val, int dummy __unused, int s,
const struct afswtch *afp)
{
uint32_t grekey = strtol(val, NULL, 0);
strlcpy(ifr.ifr_name, name, sizeof (ifr.ifr_name));
ifr.ifr_data = (caddr_t)&grekey;
if (ioctl(s, GRESKEY, (caddr_t)&ifr) < 0)
warn("ioctl (set grekey)");
}
static void
setifgreport(const char *val, int dummy __unused, int s,
const struct afswtch *afp)
{
uint32_t udpport = strtol(val, NULL, 0);
strlcpy(ifr.ifr_name, name, sizeof (ifr.ifr_name));
ifr.ifr_data = (caddr_t)&udpport;
if (ioctl(s, GRESPORT, (caddr_t)&ifr) < 0)
warn("ioctl (set udpport)");
}
static void
setifgreopts(const char *val, int d, int s, const struct afswtch *afp)
{
uint32_t opts;
ifr.ifr_data = (caddr_t)&opts;
if (ioctl(s, GREGOPTS, &ifr) == -1) {
warn("ioctl(GREGOPTS)");
return;
}
if (d < 0)
opts &= ~(-d);
else
opts |= d;
if (ioctl(s, GRESOPTS, &ifr) == -1) {
warn("ioctl(GIFSOPTS)");
return;
}
}
static struct cmd gre_cmds[] = {
DEF_CMD_ARG("grekey", setifgrekey),
DEF_CMD_ARG("udpport", setifgreport),
DEF_CMD("enable_csum", GRE_ENABLE_CSUM, setifgreopts),
DEF_CMD("-enable_csum",-GRE_ENABLE_CSUM,setifgreopts),
DEF_CMD("enable_seq", GRE_ENABLE_SEQ, setifgreopts),
DEF_CMD("-enable_seq",-GRE_ENABLE_SEQ, setifgreopts),
DEF_CMD("udpencap", GRE_UDPENCAP, setifgreopts),
DEF_CMD("-udpencap",-GRE_UDPENCAP, setifgreopts),
};
static struct afswtch af_gre = {
.af_name = "af_gre",
.af_af = AF_UNSPEC,
.af_other_status = gre_status,
};
static __constructor void
gre_ctor(void)
{
size_t i;
for (i = 0; i < nitems(gre_cmds); i++)
cmd_register(&gre_cmds[i]);
af_register(&af_gre);
}