freebsd-dev/sys/netinet/in_gif.c
Gleb Smirnoff c8ee75f231 Use network epoch to protect local IPv4 addresses hash.
The modification to the hash are already naturally locked by
in_control_sx.  Convert the hash lists to CK lists. Remove the
in_ifaddr_rmlock. Assert the network epoch where necessary.

Most cases when the hash lookup is done the epoch is already entered.
Cover a few cases, that need entering the epoch, which mostly is
initial configuration of tunnel interfaces and multicast addresses.

Reviewed by:		melifaro
Differential revision:	https://reviews.freebsd.org/D32584
2021-10-22 14:40:53 -07:00

464 lines
12 KiB
C

/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
* Copyright (c) 2018 Andrey V. Elsukov <ae@FreeBSD.org>
* 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 project 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 PROJECT 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 PROJECT 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.
*
* $KAME: in_gif.c,v 1.54 2001/05/14 14:02:16 itojun Exp $
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_inet.h"
#include "opt_inet6.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/jail.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <sys/mbuf.h>
#include <sys/errno.h>
#include <sys/kernel.h>
#include <sys/sysctl.h>
#include <sys/malloc.h>
#include <sys/proc.h>
#include <net/ethernet.h>
#include <net/if.h>
#include <net/if_var.h>
#include <net/route.h>
#include <net/vnet.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h>
#include <netinet/in_var.h>
#include <netinet/ip_encap.h>
#include <netinet/ip_ecn.h>
#include <netinet/in_fib.h>
#ifdef INET6
#include <netinet/ip6.h>
#endif
#include <net/if_gif.h>
#define GIF_TTL 30
VNET_DEFINE_STATIC(int, ip_gif_ttl) = GIF_TTL;
#define V_ip_gif_ttl VNET(ip_gif_ttl)
SYSCTL_INT(_net_inet_ip, IPCTL_GIF_TTL, gifttl, CTLFLAG_VNET | CTLFLAG_RW,
&VNET_NAME(ip_gif_ttl), 0, "Default TTL value for encapsulated packets");
/*
* We keep interfaces in a hash table using src+dst as key.
* Interfaces with GIF_IGNORE_SOURCE flag are linked into plain list.
*/
VNET_DEFINE_STATIC(struct gif_list *, ipv4_hashtbl) = NULL;
VNET_DEFINE_STATIC(struct gif_list *, ipv4_srchashtbl) = NULL;
VNET_DEFINE_STATIC(struct gif_list, ipv4_list) = CK_LIST_HEAD_INITIALIZER();
#define V_ipv4_hashtbl VNET(ipv4_hashtbl)
#define V_ipv4_srchashtbl VNET(ipv4_srchashtbl)
#define V_ipv4_list VNET(ipv4_list)
#define GIF_HASH(src, dst) (V_ipv4_hashtbl[\
in_gif_hashval((src), (dst)) & (GIF_HASH_SIZE - 1)])
#define GIF_SRCHASH(src) (V_ipv4_srchashtbl[\
fnv_32_buf(&(src), sizeof(src), FNV1_32_INIT) & (GIF_HASH_SIZE - 1)])
#define GIF_HASH_SC(sc) GIF_HASH((sc)->gif_iphdr->ip_src.s_addr,\
(sc)->gif_iphdr->ip_dst.s_addr)
static uint32_t
in_gif_hashval(in_addr_t src, in_addr_t dst)
{
uint32_t ret;
ret = fnv_32_buf(&src, sizeof(src), FNV1_32_INIT);
return (fnv_32_buf(&dst, sizeof(dst), ret));
}
static int
in_gif_checkdup(const struct gif_softc *sc, in_addr_t src, in_addr_t dst)
{
struct gif_softc *tmp;
if (sc->gif_family == AF_INET &&
sc->gif_iphdr->ip_src.s_addr == src &&
sc->gif_iphdr->ip_dst.s_addr == dst)
return (EEXIST);
CK_LIST_FOREACH(tmp, &GIF_HASH(src, dst), chain) {
if (tmp == sc)
continue;
if (tmp->gif_iphdr->ip_src.s_addr == src &&
tmp->gif_iphdr->ip_dst.s_addr == dst)
return (EADDRNOTAVAIL);
}
return (0);
}
/*
* Check that ingress address belongs to local host.
*/
static void
in_gif_set_running(struct gif_softc *sc)
{
if (in_localip(sc->gif_iphdr->ip_src))
GIF2IFP(sc)->if_drv_flags |= IFF_DRV_RUNNING;
else
GIF2IFP(sc)->if_drv_flags &= ~IFF_DRV_RUNNING;
}
/*
* ifaddr_event handler.
* Clear IFF_DRV_RUNNING flag when ingress address disappears to prevent
* source address spoofing.
*/
static void
in_gif_srcaddr(void *arg __unused, const struct sockaddr *sa,
int event __unused)
{
const struct sockaddr_in *sin;
struct gif_softc *sc;
/* Check that VNET is ready */
if (V_ipv4_hashtbl == NULL)
return;
NET_EPOCH_ASSERT();
sin = (const struct sockaddr_in *)sa;
CK_LIST_FOREACH(sc, &GIF_SRCHASH(sin->sin_addr.s_addr), srchash) {
if (sc->gif_iphdr->ip_src.s_addr != sin->sin_addr.s_addr)
continue;
in_gif_set_running(sc);
}
}
static void
in_gif_attach(struct gif_softc *sc)
{
if (sc->gif_options & GIF_IGNORE_SOURCE)
CK_LIST_INSERT_HEAD(&V_ipv4_list, sc, chain);
else
CK_LIST_INSERT_HEAD(&GIF_HASH_SC(sc), sc, chain);
CK_LIST_INSERT_HEAD(&GIF_SRCHASH(sc->gif_iphdr->ip_src.s_addr),
sc, srchash);
}
int
in_gif_setopts(struct gif_softc *sc, u_int options)
{
/* NOTE: we are protected with gif_ioctl_sx lock */
MPASS(sc->gif_family == AF_INET);
MPASS(sc->gif_options != options);
if ((options & GIF_IGNORE_SOURCE) !=
(sc->gif_options & GIF_IGNORE_SOURCE)) {
CK_LIST_REMOVE(sc, srchash);
CK_LIST_REMOVE(sc, chain);
sc->gif_options = options;
in_gif_attach(sc);
}
return (0);
}
int
in_gif_ioctl(struct gif_softc *sc, u_long cmd, caddr_t data)
{
struct ifreq *ifr = (struct ifreq *)data;
struct epoch_tracker et;
struct sockaddr_in *dst, *src;
struct ip *ip;
int error;
/* NOTE: we are protected with gif_ioctl_sx lock */
error = EINVAL;
switch (cmd) {
case SIOCSIFPHYADDR:
src = &((struct in_aliasreq *)data)->ifra_addr;
dst = &((struct in_aliasreq *)data)->ifra_dstaddr;
/* sanity checks */
if (src->sin_family != dst->sin_family ||
src->sin_family != AF_INET ||
src->sin_len != dst->sin_len ||
src->sin_len != sizeof(*src))
break;
if (src->sin_addr.s_addr == INADDR_ANY ||
dst->sin_addr.s_addr == INADDR_ANY) {
error = EADDRNOTAVAIL;
break;
}
if (V_ipv4_hashtbl == NULL) {
V_ipv4_hashtbl = gif_hashinit();
V_ipv4_srchashtbl = gif_hashinit();
}
error = in_gif_checkdup(sc, src->sin_addr.s_addr,
dst->sin_addr.s_addr);
if (error == EADDRNOTAVAIL)
break;
if (error == EEXIST) {
/* Addresses are the same. Just return. */
error = 0;
break;
}
ip = malloc(sizeof(*ip), M_GIF, M_WAITOK | M_ZERO);
ip->ip_src.s_addr = src->sin_addr.s_addr;
ip->ip_dst.s_addr = dst->sin_addr.s_addr;
if (sc->gif_family != 0) {
/* Detach existing tunnel first */
CK_LIST_REMOVE(sc, srchash);
CK_LIST_REMOVE(sc, chain);
GIF_WAIT();
free(sc->gif_hdr, M_GIF);
/* XXX: should we notify about link state change? */
}
sc->gif_family = AF_INET;
sc->gif_iphdr = ip;
in_gif_attach(sc);
NET_EPOCH_ENTER(et);
in_gif_set_running(sc);
NET_EPOCH_EXIT(et);
break;
case SIOCGIFPSRCADDR:
case SIOCGIFPDSTADDR:
if (sc->gif_family != AF_INET) {
error = EADDRNOTAVAIL;
break;
}
src = (struct sockaddr_in *)&ifr->ifr_addr;
memset(src, 0, sizeof(*src));
src->sin_family = AF_INET;
src->sin_len = sizeof(*src);
src->sin_addr = (cmd == SIOCGIFPSRCADDR) ?
sc->gif_iphdr->ip_src: sc->gif_iphdr->ip_dst;
error = prison_if(curthread->td_ucred, (struct sockaddr *)src);
if (error != 0)
memset(src, 0, sizeof(*src));
break;
}
return (error);
}
int
in_gif_output(struct ifnet *ifp, struct mbuf *m, int proto, uint8_t ecn)
{
struct gif_softc *sc = ifp->if_softc;
struct ip *ip;
int len;
/* prepend new IP header */
NET_EPOCH_ASSERT();
len = sizeof(struct ip);
#ifndef __NO_STRICT_ALIGNMENT
if (proto == IPPROTO_ETHERIP)
len += ETHERIP_ALIGN;
#endif
M_PREPEND(m, len, M_NOWAIT);
if (m == NULL)
return (ENOBUFS);
#ifndef __NO_STRICT_ALIGNMENT
if (proto == IPPROTO_ETHERIP) {
len = mtod(m, vm_offset_t) & 3;
KASSERT(len == 0 || len == ETHERIP_ALIGN,
("in_gif_output: unexpected misalignment"));
m->m_data += len;
m->m_len -= ETHERIP_ALIGN;
}
#endif
ip = mtod(m, struct ip *);
MPASS(sc->gif_family == AF_INET);
bcopy(sc->gif_iphdr, ip, sizeof(struct ip));
ip->ip_p = proto;
/* version will be set in ip_output() */
ip->ip_ttl = V_ip_gif_ttl;
ip->ip_len = htons(m->m_pkthdr.len);
ip->ip_tos = ecn;
return (ip_output(m, NULL, NULL, 0, NULL, NULL));
}
static int
in_gif_input(struct mbuf *m, int off, int proto, void *arg)
{
struct gif_softc *sc = arg;
struct ifnet *gifp;
struct ip *ip;
uint8_t ecn;
NET_EPOCH_ASSERT();
if (sc == NULL) {
m_freem(m);
KMOD_IPSTAT_INC(ips_nogif);
return (IPPROTO_DONE);
}
gifp = GIF2IFP(sc);
if ((gifp->if_flags & IFF_UP) != 0) {
ip = mtod(m, struct ip *);
ecn = ip->ip_tos;
m_adj(m, off);
gif_input(m, gifp, proto, ecn);
} else {
m_freem(m);
KMOD_IPSTAT_INC(ips_nogif);
}
return (IPPROTO_DONE);
}
static int
in_gif_lookup(const struct mbuf *m, int off, int proto, void **arg)
{
const struct ip *ip;
struct gif_softc *sc;
int ret;
if (V_ipv4_hashtbl == NULL)
return (0);
NET_EPOCH_ASSERT();
ip = mtod(m, const struct ip *);
/*
* NOTE: it is safe to iterate without any locking here, because softc
* can be reclaimed only when we are not within net_epoch_preempt
* section, but ip_encap lookup+input are executed in epoch section.
*/
ret = 0;
CK_LIST_FOREACH(sc, &GIF_HASH(ip->ip_dst.s_addr,
ip->ip_src.s_addr), chain) {
/*
* This is an inbound packet, its ip_dst is source address
* in softc.
*/
if (sc->gif_iphdr->ip_src.s_addr == ip->ip_dst.s_addr &&
sc->gif_iphdr->ip_dst.s_addr == ip->ip_src.s_addr) {
ret = ENCAP_DRV_LOOKUP;
goto done;
}
}
/*
* No exact match.
* Check the list of interfaces with GIF_IGNORE_SOURCE flag.
*/
CK_LIST_FOREACH(sc, &V_ipv4_list, chain) {
if (sc->gif_iphdr->ip_src.s_addr == ip->ip_dst.s_addr) {
ret = 32 + 8; /* src + proto */
goto done;
}
}
return (0);
done:
if ((GIF2IFP(sc)->if_flags & IFF_UP) == 0)
return (0);
/* ingress filters on outer source */
if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0) {
if (fib4_check_urpf(sc->gif_fibnum, ip->ip_src, 0, NHR_NONE,
m->m_pkthdr.rcvif) == 0)
return (0);
}
*arg = sc;
return (ret);
}
static const struct srcaddrtab *ipv4_srcaddrtab;
static struct {
const struct encap_config encap;
const struct encaptab *cookie;
} ipv4_encap_cfg[] = {
{
.encap = {
.proto = IPPROTO_IPV4,
.min_length = 2 * sizeof(struct ip),
.exact_match = ENCAP_DRV_LOOKUP,
.lookup = in_gif_lookup,
.input = in_gif_input
},
},
#ifdef INET6
{
.encap = {
.proto = IPPROTO_IPV6,
.min_length = sizeof(struct ip) +
sizeof(struct ip6_hdr),
.exact_match = ENCAP_DRV_LOOKUP,
.lookup = in_gif_lookup,
.input = in_gif_input
},
},
#endif
{
.encap = {
.proto = IPPROTO_ETHERIP,
.min_length = sizeof(struct ip) +
sizeof(struct etherip_header) +
sizeof(struct ether_header),
.exact_match = ENCAP_DRV_LOOKUP,
.lookup = in_gif_lookup,
.input = in_gif_input
},
}
};
void
in_gif_init(void)
{
int i;
if (!IS_DEFAULT_VNET(curvnet))
return;
ipv4_srcaddrtab = ip_encap_register_srcaddr(in_gif_srcaddr,
NULL, M_WAITOK);
for (i = 0; i < nitems(ipv4_encap_cfg); i++)
ipv4_encap_cfg[i].cookie = ip_encap_attach(
&ipv4_encap_cfg[i].encap, NULL, M_WAITOK);
}
void
in_gif_uninit(void)
{
int i;
if (IS_DEFAULT_VNET(curvnet)) {
for (i = 0; i < nitems(ipv4_encap_cfg); i++)
ip_encap_detach(ipv4_encap_cfg[i].cookie);
ip_encap_unregister_srcaddr(ipv4_srcaddrtab);
}
if (V_ipv4_hashtbl != NULL) {
gif_hashdestroy(V_ipv4_hashtbl);
V_ipv4_hashtbl = NULL;
GIF_WAIT();
gif_hashdestroy(V_ipv4_srchashtbl);
}
}