freebsd-dev/sys/net/if_stf.c
Zhenlei Huang c373e1d6ad if_stf: Delete unreachable code
As the flag M_WAITOK is passed to ip_encap_attach(), then the function
will never return NULL, and the following code within NULL check branch
will be unreachable.

No functional change intended.

Reviewed by:	kp
Fixes:		6d8fdfa9d5 Rework IP encapsulation handling code
MFC after:	1 week
Differential Revision:  https://reviews.freebsd.org/D39746
2023-04-23 12:47:57 +08:00

1058 lines
28 KiB
C

/* $FreeBSD$ */
/* $KAME: if_stf.c,v 1.73 2001/12/03 11:08:30 keiichi Exp $ */
/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (C) 2000 WIDE Project.
* Copyright (c) 2010 Hiroki Sato <hrs@FreeBSD.org>
* Copyright (c) 2013 Ermal Luci <eri@FreeBSD.org>
* Copyright (c) 2017-2021 Rubicon Communications, LLC (Netgate)
* 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.
*/
/*
* 6to4 interface, based on RFC3056.
*
* 6to4 interface is NOT capable of link-layer (I mean, IPv4) multicasting.
* There is no address mapping defined from IPv6 multicast address to IPv4
* address. Therefore, we do not have IFF_MULTICAST on the interface.
*
* Due to the lack of address mapping for link-local addresses, we cannot
* throw packets toward link-local addresses (fe80::x). Also, we cannot throw
* packets to link-local multicast addresses (ff02::x).
*
* Here are interesting symptoms due to the lack of link-local address:
*
* Unicast routing exchange:
* - RIPng: Impossible. Uses link-local multicast packet toward ff02::9,
* and link-local addresses as nexthop.
* - OSPFv6: Impossible. OSPFv6 assumes that there's link-local address
* assigned to the link, and makes use of them. Also, HELLO packets use
* link-local multicast addresses (ff02::5 and ff02::6).
* - BGP4+: Maybe. You can only use global address as nexthop, and global
* address as TCP endpoint address.
*
* Multicast routing protocols:
* - PIM: Hello packet cannot be used to discover adjacent PIM routers.
* Adjacent PIM routers must be configured manually (is it really spec-wise
* correct thing to do?).
*
* ICMPv6:
* - Redirects cannot be used due to the lack of link-local address.
*
* stf interface does not have, and will not need, a link-local address.
* It seems to have no real benefit and does not help the above symptoms much.
* Even if we assign link-locals to interface, we cannot really
* use link-local unicast/multicast on top of 6to4 cloud (since there's no
* encapsulation defined for link-local address), and the above analysis does
* not change. RFC3056 does not mandate the assignment of link-local address
* either.
*
* 6to4 interface has security issues. Refer to
* http://playground.iijlab.net/i-d/draft-itojun-ipv6-transition-abuse-00.txt
* for details. The code tries to filter out some of malicious packets.
* Note that there is no way to be 100% secure.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <sys/mbuf.h>
#include <sys/endian.h>
#include <sys/errno.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/module.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/queue.h>
#include <sys/sdt.h>
#include <sys/sysctl.h>
#include <machine/cpu.h>
#include <sys/malloc.h>
#include <net/if.h>
#include <net/if_var.h>
#include <net/if_private.h>
#include <net/if_clone.h>
#include <net/route.h>
#include <net/route/nhop.h>
#include <net/netisr.h>
#include <net/if_stf.h>
#include <net/if_types.h>
#include <net/vnet.h>
#include <netinet/in.h>
#include <netinet/in_fib.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h>
#include <netinet/in_var.h>
#include <netinet/ip6.h>
#include <netinet6/in6_fib.h>
#include <netinet6/ip6_var.h>
#include <netinet6/in6_var.h>
#include <netinet/ip_ecn.h>
#include <netinet/ip_encap.h>
#include <machine/stdarg.h>
#include <net/bpf.h>
#include <security/mac/mac_framework.h>
SDT_PROVIDER_DEFINE(if_stf);
SDT_PROBE_DEFINE3(if_stf, , encapcheck, in, "struct mbuf *", "int", "int");
SDT_PROBE_DEFINE0(if_stf, , encapcheck, accept);
SDT_PROBE_DEFINE3(if_stf, , getsrcifa6, in, "struct ifnet *",
"struct in6_addr *", "struct in6_addr *");
SDT_PROBE_DEFINE2(if_stf, , getsrcifa6, found, "struct in6_addr *",
"struct in6_addr *");
SDT_PROBE_DEFINE0(if_stf, , getsrcifa6, notfound);
SDT_PROBE_DEFINE4(if_stf, , stf_output, in, "struct ifnet *", "struct mbuf *",
"struct sockaddr *", "struct route *");
SDT_PROBE_DEFINE2(if_stf, , stf_output, error, "int", "int");
SDT_PROBE_DEFINE1(if_stf, , stf_output, out, "int");
SDT_PROBE_DEFINE3(if_stf, , checkaddr6, in, "struct stf_softc *",
"struct in6_addr *", "struct ifnet *");
SDT_PROBE_DEFINE2(if_stf, , checkaddr6, out, "int", "int");
SDT_PROBE_DEFINE3(if_stf, , stf_input, in, "struct mbuf *", "int", "int");
SDT_PROBE_DEFINE2(if_stf, , stf_input, out, "int", "int");
SDT_PROBE_DEFINE3(if_stf, , ioctl, sv4net, "struct in_addr *",
"struct in_addr *", "int");
SDT_PROBE_DEFINE1(if_stf, , ioctl, sdstv4, "struct in_addr *");
SDT_PROBE_DEFINE1(if_stf, , ioctl, ifaddr, "struct ifaddr *");
SDT_PROBE_DEFINE4(if_stf, , getin4addr_in6, out, "struct in6_addr *",
"struct in6_addr *", "struct in6_addr *", "struct sockaddr_in *");
SDT_PROBE_DEFINE2(if_stf, , getin4addr, in, "struct in6_addr *", "struct in6_addr *");
SDT_PROBE_DEFINE1(if_stf, , getin4addr, out, "struct sockaddr_in *");
SYSCTL_DECL(_net_link);
static SYSCTL_NODE(_net_link, IFT_STF, stf, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
"6to4 Interface");
static int stf_permit_rfc1918 = 0;
SYSCTL_INT(_net_link_stf, OID_AUTO, permit_rfc1918, CTLFLAG_RWTUN,
&stf_permit_rfc1918, 0, "Permit the use of private IPv4 addresses");
#define STFUNIT 0
#define IN6_IS_ADDR_6TO4(x) (ntohs((x)->s6_addr16[0]) == 0x2002)
/*
* XXX: Return a pointer with 16-bit aligned. Don't cast it to
* struct in_addr *; use bcopy() instead.
*/
#define GET_V4(x) (&(x)->s6_addr16[1])
struct stf_softc {
struct ifnet *sc_ifp;
in_addr_t braddr; /* Border relay IPv4 address */
in_addr_t srcv4_addr; /* Our IPv4 WAN address */
u_int v4prefixlen; /* How much of the v4 address to include in our address. */
u_int sc_fibnum;
const struct encaptab *encap_cookie;
};
#define STF2IFP(sc) ((sc)->sc_ifp)
static const char stfname[] = "stf";
static MALLOC_DEFINE(M_STF, stfname, "6to4 Tunnel Interface");
static const int ip_stf_ttl = 40;
static int in_stf_input(struct mbuf *, int, int, void *);
static char *stfnames[] = {"stf0", "stf", "6to4", NULL};
static int stfmodevent(module_t, int, void *);
static int stf_encapcheck(const struct mbuf *, int, int, void *);
static int stf_getsrcifa6(struct ifnet *, struct in6_addr *, struct in6_addr *);
static int stf_output(struct ifnet *, struct mbuf *, const struct sockaddr *,
struct route *);
static int isrfc1918addr(struct in_addr *);
static int stf_checkaddr4(struct stf_softc *, struct in_addr *,
struct ifnet *);
static int stf_checkaddr6(struct stf_softc *, struct in6_addr *,
struct ifnet *);
static struct sockaddr_in *stf_getin4addr_in6(struct stf_softc *,
struct sockaddr_in *, struct in6_addr, struct in6_addr,
struct in6_addr);
static struct sockaddr_in *stf_getin4addr(struct stf_softc *,
struct sockaddr_in *, struct in6_addr, struct in6_addr);
static int stf_ioctl(struct ifnet *, u_long, caddr_t);
VNET_DEFINE_STATIC(struct if_clone *, stf_cloner);
#define V_stf_cloner VNET(stf_cloner)
static const struct encap_config ipv4_encap_cfg = {
.proto = IPPROTO_IPV6,
.min_length = sizeof(struct ip),
.exact_match = (sizeof(in_addr_t) << 3) + 8,
.check = stf_encapcheck,
.input = in_stf_input
};
static int
stf_clone_match(struct if_clone *ifc, const char *name)
{
int i;
for(i = 0; stfnames[i] != NULL; i++) {
if (strcmp(stfnames[i], name) == 0)
return (1);
}
return (0);
}
static int
stf_clone_create(struct if_clone *ifc, char *name, size_t len,
struct ifc_data *ifd, struct ifnet **ifpp)
{
char *dp;
int err, unit, wildcard;
struct stf_softc *sc;
struct ifnet *ifp;
err = ifc_name2unit(name, &unit);
if (err != 0)
return (err);
wildcard = (unit < 0);
/*
* We can only have one unit, but since unit allocation is
* already locked, we use it to keep from allocating extra
* interfaces.
*/
unit = STFUNIT;
err = ifc_alloc_unit(ifc, &unit);
if (err != 0)
return (err);
sc = malloc(sizeof(struct stf_softc), M_STF, M_WAITOK | M_ZERO);
ifp = STF2IFP(sc) = if_alloc(IFT_STF);
if (ifp == NULL) {
free(sc, M_STF);
ifc_free_unit(ifc, unit);
return (ENOSPC);
}
ifp->if_softc = sc;
sc->sc_fibnum = curthread->td_proc->p_fibnum;
/*
* Set the name manually rather then using if_initname because
* we don't conform to the default naming convention for interfaces.
* In the wildcard case, we need to update the name.
*/
if (wildcard) {
for (dp = name; *dp != '\0'; dp++);
if (snprintf(dp, len - (dp-name), "%d", unit) >
len - (dp-name) - 1) {
/*
* This can only be a programmer error and
* there's no straightforward way to recover if
* it happens.
*/
panic("if_clone_create(): interface name too long");
}
}
strlcpy(ifp->if_xname, name, IFNAMSIZ);
ifp->if_dname = stfname;
ifp->if_dunit = IF_DUNIT_NONE;
sc->encap_cookie = ip_encap_attach(&ipv4_encap_cfg, sc, M_WAITOK);
ifp->if_mtu = IPV6_MMTU;
ifp->if_ioctl = stf_ioctl;
ifp->if_output = stf_output;
ifp->if_snd.ifq_maxlen = ifqmaxlen;
if_attach(ifp);
bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
*ifpp = ifp;
return (0);
}
static int
stf_clone_destroy(struct if_clone *ifc, struct ifnet *ifp, uint32_t flags)
{
struct stf_softc *sc = ifp->if_softc;
int err __unused;
err = ip_encap_detach(sc->encap_cookie);
KASSERT(err == 0, ("Unexpected error detaching encap_cookie"));
bpfdetach(ifp);
if_detach(ifp);
if_free(ifp);
free(sc, M_STF);
ifc_free_unit(ifc, STFUNIT);
return (0);
}
static void
vnet_stf_init(const void *unused __unused)
{
struct if_clone_addreq req = {
.match_f = stf_clone_match,
.create_f = stf_clone_create,
.destroy_f = stf_clone_destroy,
};
V_stf_cloner = ifc_attach_cloner(stfname, &req);
}
VNET_SYSINIT(vnet_stf_init, SI_SUB_PSEUDO, SI_ORDER_ANY, vnet_stf_init, NULL);
static void
vnet_stf_uninit(const void *unused __unused)
{
if_clone_detach(V_stf_cloner);
V_stf_cloner = NULL;
}
VNET_SYSUNINIT(vnet_stf_uninit, SI_SUB_PSEUDO, SI_ORDER_ANY, vnet_stf_uninit,
NULL);
static int
stfmodevent(module_t mod, int type, void *data)
{
switch (type) {
case MOD_LOAD:
/* Done in vnet_stf_init() */
break;
case MOD_UNLOAD:
/* Done in vnet_stf_uninit() */
break;
default:
return (EOPNOTSUPP);
}
return (0);
}
static moduledata_t stf_mod = {
"if_stf",
stfmodevent,
0
};
DECLARE_MODULE(if_stf, stf_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
MODULE_VERSION(if_stf, 2);
static int
stf_encapcheck(const struct mbuf *m, int off, int proto, void *arg)
{
struct ip ip;
struct stf_softc *sc;
struct in6_addr addr6, mask6;
struct sockaddr_in sin4addr, sin4mask;
SDT_PROBE3(if_stf, , encapcheck, in, m, off, proto);
sc = (struct stf_softc *)arg;
if (sc == NULL)
return (0);
if ((STF2IFP(sc)->if_flags & IFF_UP) == 0)
return (0);
/* IFF_LINK0 means "no decapsulation" */
if ((STF2IFP(sc)->if_flags & IFF_LINK0) != 0)
return (0);
if (proto != IPPROTO_IPV6)
return (0);
m_copydata(m, 0, sizeof(ip), (caddr_t)&ip);
if (ip.ip_v != 4)
return (0);
if (stf_getsrcifa6(STF2IFP(sc), &addr6, &mask6) != 0)
return (0);
if (sc->srcv4_addr != INADDR_ANY) {
sin4addr.sin_addr.s_addr = sc->srcv4_addr;
sin4addr.sin_family = AF_INET;
} else
if (stf_getin4addr(sc, &sin4addr, addr6, mask6) == NULL)
return (0);
if (sin4addr.sin_addr.s_addr != ip.ip_dst.s_addr)
return (0);
if (IN6_IS_ADDR_6TO4(&addr6)) {
/*
* 6to4 (RFC 3056).
* Check if IPv4 src matches the IPv4 address derived
* from the local 6to4 address masked by prefixmask.
* success on: src = 10.1.1.1, ia6->ia_addr = 2002:0a00:.../24
* fail on: src = 10.1.1.1, ia6->ia_addr = 2002:0b00:.../24
*/
memcpy(&sin4mask.sin_addr, GET_V4(&mask6),
sizeof(sin4mask.sin_addr));
if ((sin4addr.sin_addr.s_addr & sin4mask.sin_addr.s_addr) !=
(ip.ip_src.s_addr & sin4mask.sin_addr.s_addr))
return (0);
} else {
/* 6rd (RFC 5569) */
/*
* No restriction on the src address in the case of
* 6rd because the stf(4) interface always has a
* prefix which covers whole of IPv4 src address
* range. So, stf_output() will catch all of
* 6rd-capsuled IPv4 traffic with suspicious inner dst
* IPv4 address (i.e. the IPv6 destination address is
* one the admin does not like to route to outside),
* and then it discard them silently.
*/
}
SDT_PROBE0(if_stf, , encapcheck, accept);
/* stf interface makes single side match only */
return (32);
}
static int
stf_getsrcifa6(struct ifnet *ifp, struct in6_addr *addr, struct in6_addr *mask)
{
struct ifaddr *ia;
struct in_ifaddr *ia4;
struct in6_addr addr6, mask6;
struct sockaddr_in sin4;
struct stf_softc *sc;
struct in_addr in;
NET_EPOCH_ASSERT();
sc = ifp->if_softc;
SDT_PROBE3(if_stf, , getsrcifa6, in, ifp, addr, mask);
CK_STAILQ_FOREACH(ia, &ifp->if_addrhead, ifa_link) {
if (ia->ifa_addr->sa_family != AF_INET6)
continue;
addr6 = *IFA_IN6(ia);
mask6 = *IFA_MASKIN6(ia);
if (sc->srcv4_addr != INADDR_ANY)
bcopy(&sc->srcv4_addr, &in, sizeof(in));
else {
if (stf_getin4addr(sc, &sin4, addr6, mask6) == NULL)
continue;
bcopy(&sin4.sin_addr, &in, sizeof(in));
}
CK_LIST_FOREACH(ia4, INADDR_HASH(in.s_addr), ia_hash)
if (ia4->ia_addr.sin_addr.s_addr == in.s_addr)
break;
if (ia4 == NULL)
continue;
*addr = addr6;
*mask = mask6;
SDT_PROBE2(if_stf, , getsrcifa6, found, addr, mask);
return (0);
}
SDT_PROBE0(if_stf, , getsrcifa6, notfound);
return (ENOENT);
}
static int
stf_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
struct route *ro)
{
struct stf_softc *sc;
const struct sockaddr_in6 *dst6;
struct sockaddr_in dst4, src4;
u_int8_t tos;
struct ip *ip;
struct ip6_hdr *ip6;
struct in6_addr addr6, mask6;
int error;
SDT_PROBE4(if_stf, , stf_output, in, ifp, m, dst, ro);
#ifdef MAC
error = mac_ifnet_check_transmit(ifp, m);
if (error) {
m_freem(m);
SDT_PROBE2(if_stf, , stf_output, error, error, __LINE__);
return (error);
}
#endif
sc = ifp->if_softc;
dst6 = (const struct sockaddr_in6 *)dst;
/* just in case */
if ((ifp->if_flags & IFF_UP) == 0) {
m_freem(m);
if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
SDT_PROBE2(if_stf, , stf_output, error, ENETDOWN, __LINE__);
return (ENETDOWN);
}
/*
* If we don't have an ip4 address that match my inner ip6 address,
* we shouldn't generate output. Without this check, we'll end up
* using wrong IPv4 source.
*/
if (stf_getsrcifa6(ifp, &addr6, &mask6) != 0) {
m_freem(m);
if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
SDT_PROBE2(if_stf, , stf_output, error, ENETDOWN, __LINE__);
return (ENETDOWN);
}
if (m->m_len < sizeof(*ip6)) {
m = m_pullup(m, sizeof(*ip6));
if (!m) {
if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
SDT_PROBE2(if_stf, , stf_output, error, ENOBUFS,
__LINE__);
return (ENOBUFS);
}
}
ip6 = mtod(m, struct ip6_hdr *);
tos = IPV6_TRAFFIC_CLASS(ip6);
/*
* Pickup the right outer dst addr from the list of candidates.
* ip6_dst has priority as it may be able to give us shorter IPv4 hops.
*/
if (stf_getin4addr_in6(sc, &dst4, addr6, mask6,
ip6->ip6_dst) == NULL) {
if (sc->braddr != INADDR_ANY)
dst4.sin_addr.s_addr = sc->braddr;
else if (stf_getin4addr_in6(sc, &dst4, addr6, mask6,
dst6->sin6_addr) == NULL) {
m_freem(m);
if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
SDT_PROBE2(if_stf, , stf_output, error, ENETUNREACH,
__LINE__);
return (ENETUNREACH);
}
}
if (bpf_peers_present(ifp->if_bpf)) {
/*
* We need to prepend the address family as
* a four byte field. Cons up a dummy header
* to pacify bpf. This is safe because bpf
* will only read from the mbuf (i.e., it won't
* try to free it or keep a pointer a to it).
*/
u_int af = AF_INET6;
bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m);
}
M_PREPEND(m, sizeof(struct ip), M_NOWAIT);
if (m == NULL) {
if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
SDT_PROBE2(if_stf, , stf_output, error, ENOBUFS, __LINE__);
return (ENOBUFS);
}
ip = mtod(m, struct ip *);
bzero(ip, sizeof(*ip));
if (sc->srcv4_addr != INADDR_ANY)
src4.sin_addr.s_addr = sc->srcv4_addr;
else if (stf_getin4addr(sc, &src4, addr6, mask6) == NULL) {
m_freem(m);
if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
SDT_PROBE2(if_stf, , stf_output, error, ENETUNREACH, __LINE__);
return (ENETUNREACH);
}
bcopy(&src4.sin_addr, &ip->ip_src, sizeof(ip->ip_src));
bcopy(&dst4.sin_addr, &ip->ip_dst, sizeof(ip->ip_dst));
ip->ip_p = IPPROTO_IPV6;
ip->ip_ttl = ip_stf_ttl;
ip->ip_len = htons(m->m_pkthdr.len);
if (ifp->if_flags & IFF_LINK1)
ip_ecn_ingress(ECN_ALLOWED, &ip->ip_tos, &tos);
else
ip_ecn_ingress(ECN_NOCARE, &ip->ip_tos, &tos);
M_SETFIB(m, sc->sc_fibnum);
if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
error = ip_output(m, NULL, NULL, 0, NULL, NULL);
SDT_PROBE1(if_stf, , stf_output, out, error);
return (error);
}
static int
isrfc1918addr(struct in_addr *in)
{
/*
* returns 1 if private address range:
* 10.0.0.0/8 172.16.0.0/12 192.168.0.0/16
*/
if (stf_permit_rfc1918 == 0 && (
(ntohl(in->s_addr) & 0xff000000) >> 24 == 10 ||
(ntohl(in->s_addr) & 0xfff00000) >> 16 == 172 * 256 + 16 ||
(ntohl(in->s_addr) & 0xffff0000) >> 16 == 192 * 256 + 168))
return (1);
return (0);
}
static int
stf_checkaddr4(struct stf_softc *sc, struct in_addr *in, struct ifnet *inifp)
{
struct in_ifaddr *ia4;
/*
* reject packets with the following address:
* 224.0.0.0/4 0.0.0.0/8 127.0.0.0/8 255.0.0.0/8
*/
if (IN_MULTICAST(ntohl(in->s_addr)))
return (-1);
switch ((ntohl(in->s_addr) & 0xff000000) >> 24) {
case 0: case 127: case 255:
return (-1);
}
/*
* reject packets with broadcast
*/
CK_STAILQ_FOREACH(ia4, &V_in_ifaddrhead, ia_link) {
if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
continue;
if (in->s_addr == ia4->ia_broadaddr.sin_addr.s_addr) {
return (-1);
}
}
/*
* perform ingress filter
*/
if (sc && (STF2IFP(sc)->if_flags & IFF_LINK2) == 0 && inifp) {
struct nhop_object *nh;
NET_EPOCH_ASSERT();
nh = fib4_lookup(sc->sc_fibnum, *in, 0, 0, 0);
if (nh == NULL)
return (-1);
if (nh->nh_ifp != inifp)
return (-1);
}
return (0);
}
static int
stf_checkaddr6(struct stf_softc *sc, struct in6_addr *in6, struct ifnet *inifp)
{
SDT_PROBE3(if_stf, , checkaddr6, in, sc, in6, inifp);
/*
* check 6to4 addresses
*/
if (IN6_IS_ADDR_6TO4(in6)) {
struct in_addr in4;
int ret;
bcopy(GET_V4(in6), &in4, sizeof(in4));
ret = stf_checkaddr4(sc, &in4, inifp);
SDT_PROBE2(if_stf, , checkaddr6, out, ret, __LINE__);
return (ret);
}
/*
* reject anything that look suspicious. the test is implemented
* in ip6_input too, but we check here as well to
* (1) reject bad packets earlier, and
* (2) to be safe against future ip6_input change.
*/
if (IN6_IS_ADDR_V4COMPAT(in6)) {
SDT_PROBE2(if_stf, , checkaddr6, out, -1, __LINE__);
return (-1);
}
if (IN6_IS_ADDR_V4MAPPED(in6)) {
SDT_PROBE2(if_stf, , checkaddr6, out, -1, __LINE__);
return (-1);
}
SDT_PROBE2(if_stf, , checkaddr6, out, 0, __LINE__);
return (0);
}
static int
in_stf_input(struct mbuf *m, int off, int proto, void *arg)
{
struct stf_softc *sc = arg;
struct ip ip;
struct ip6_hdr *ip6;
u_int8_t otos, itos;
struct ifnet *ifp;
struct nhop_object *nh;
NET_EPOCH_ASSERT();
SDT_PROBE3(if_stf, , stf_input, in, m, off, proto);
if (proto != IPPROTO_IPV6) {
m_freem(m);
SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, __LINE__);
return (IPPROTO_DONE);
}
m_copydata(m, 0, sizeof(struct ip), (caddr_t)&ip);
if (sc == NULL || (STF2IFP(sc)->if_flags & IFF_UP) == 0) {
m_freem(m);
SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, __LINE__);
return (IPPROTO_DONE);
}
ifp = STF2IFP(sc);
#ifdef MAC
mac_ifnet_create_mbuf(ifp, m);
#endif
/*
* perform sanity check against outer src/dst.
* for source, perform ingress filter as well.
*/
if (stf_checkaddr4(sc, &ip.ip_dst, NULL) < 0 ||
stf_checkaddr4(sc, &ip.ip_src, m->m_pkthdr.rcvif) < 0) {
m_freem(m);
SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, __LINE__);
return (IPPROTO_DONE);
}
otos = ip.ip_tos;
m_adj(m, off);
if (m->m_len < sizeof(*ip6)) {
m = m_pullup(m, sizeof(*ip6));
if (!m) {
SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE,
__LINE__);
return (IPPROTO_DONE);
}
}
ip6 = mtod(m, struct ip6_hdr *);
/*
* perform sanity check against inner src/dst.
* for source, perform ingress filter as well.
*/
if (stf_checkaddr6(sc, &ip6->ip6_dst, NULL) < 0 ||
stf_checkaddr6(sc, &ip6->ip6_src, m->m_pkthdr.rcvif) < 0) {
m_freem(m);
SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, __LINE__);
return (IPPROTO_DONE);
}
/*
* reject packets with private address range.
* (requirement from RFC3056 section 2 1st paragraph)
*/
if ((IN6_IS_ADDR_6TO4(&ip6->ip6_src) && isrfc1918addr(&ip.ip_src)) ||
(IN6_IS_ADDR_6TO4(&ip6->ip6_dst) && isrfc1918addr(&ip.ip_dst))) {
m_freem(m);
SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, __LINE__);
return (IPPROTO_DONE);
}
/*
* Ignore if the destination is the same stf interface because
* all of valid IPv6 outgoing traffic should go interfaces
* except for it.
*/
nh = fib6_lookup(sc->sc_fibnum, &ip6->ip6_dst, 0, 0, 0);
if (nh == NULL) {
m_free(m);
SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, __LINE__);
return (IPPROTO_DONE);
}
if ((nh->nh_ifp == ifp) &&
(!IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &nh->gw6_sa.sin6_addr))) {
m_free(m);
SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, __LINE__);
return (IPPROTO_DONE);
}
itos = IPV6_TRAFFIC_CLASS(ip6);
if ((ifp->if_flags & IFF_LINK1) != 0)
ip_ecn_egress(ECN_ALLOWED, &otos, &itos);
else
ip_ecn_egress(ECN_NOCARE, &otos, &itos);
ip6->ip6_flow &= ~htonl(0xff << 20);
ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
m->m_pkthdr.rcvif = ifp;
if (bpf_peers_present(ifp->if_bpf)) {
/*
* We need to prepend the address family as
* a four byte field. Cons up a dummy header
* to pacify bpf. This is safe because bpf
* will only read from the mbuf (i.e., it won't
* try to free it or keep a pointer a to it).
*/
u_int32_t af = AF_INET6;
bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m);
}
/*
* Put the packet to the network layer input queue according to the
* specified address family.
* See net/if_gif.c for possible issues with packet processing
* reorder due to extra queueing.
*/
if_inc_counter(ifp, IFCOUNTER_IPACKETS, 1);
if_inc_counter(ifp, IFCOUNTER_IBYTES, m->m_pkthdr.len);
M_SETFIB(m, ifp->if_fib);
netisr_dispatch(NETISR_IPV6, m);
SDT_PROBE2(if_stf, , stf_input, out, IPPROTO_DONE, __LINE__);
return (IPPROTO_DONE);
}
static struct sockaddr_in *
stf_getin4addr_in6(struct stf_softc *sc, struct sockaddr_in *sin,
struct in6_addr addr6, struct in6_addr mask6, struct in6_addr in6)
{
int i;
struct sockaddr_in *out;
/*
* When (src addr & src mask) != (in6 & src mask),
* the dst is not in the 6rd domain. The IPv4 address must
* not be used.
*/
for (i = 0; i < sizeof(addr6); i++) {
if ((((u_char *)&addr6)[i] & ((u_char *)&mask6)[i]) !=
(((u_char *)&in6)[i] & ((u_char *)&mask6)[i])) {
SDT_PROBE4(if_stf, , getin4addr_in6, out, &addr6,
&mask6, &in6, NULL);
return (NULL);
}
}
/* After the mask check, use in6 instead of addr6. */
out = stf_getin4addr(sc, sin, in6, mask6);
SDT_PROBE4(if_stf, , getin4addr_in6, out, &addr6, &mask6, &in6, out);
return (out);
}
static struct sockaddr_in *
stf_getin4addr(struct stf_softc *sc, struct sockaddr_in *sin,
struct in6_addr addr6, struct in6_addr mask6)
{
struct in_addr *in;
SDT_PROBE2(if_stf, , getin4addr, in, &addr6, &mask6);
memset(sin, 0, sizeof(*sin));
in = &sin->sin_addr;
if (IN6_IS_ADDR_6TO4(&addr6)) {
/* 6to4 (RFC 3056) */
bcopy(GET_V4(&addr6), in, sizeof(*in));
if (isrfc1918addr(in))
return (NULL);
} else {
/* 6rd (RFC 5569) */
in_addr_t v4prefix;
uint8_t *v6 = (uint8_t*)&addr6;
uint64_t v6prefix;
u_int plen;
u_int v4suffixlen;
v4prefix = 0;
if (sc->v4prefixlen < 32) {
v4suffixlen = 32 - sc->v4prefixlen;
v4prefix = ntohl(sc->srcv4_addr) &
(0xffffffffU << v4suffixlen);
} else {
MPASS(sc->v4prefixlen == 32);
v4suffixlen = 32;
}
plen = in6_mask2len(&mask6, NULL);
if (plen > 64)
return (NULL);
/* To make this simple we do not support prefixes longer than
* 64 bits. RFC5969 says "a 6rd delegated prefix SHOULD be /64
* or shorter." so this is a moderately safe assumption. */
v6prefix = be64toh(*(uint64_t *)v6);
/* Shift away the v6 prefix itself. */
v6prefix <<= plen;
v6prefix >>= plen;
/* Now shift away everything after the v4 address. */
v6prefix >>= 64 - plen - v4suffixlen;
sin->sin_addr.s_addr = htonl(v4prefix | (uint32_t)v6prefix);
}
SDT_PROBE1(if_stf, , getin4addr, out, sin);
return (sin);
}
static int
stf_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
{
struct ifaddr *ifa;
struct ifdrv *ifd;
struct ifreq *ifr;
struct sockaddr_in sin4;
struct stf_softc *sc_cur;
struct stfv4args args;
int error, mtu;
error = 0;
sc_cur = ifp->if_softc;
switch (cmd) {
case SIOCSDRVSPEC:
ifd = (struct ifdrv *)data;
error = priv_check(curthread, PRIV_NET_ADDIFADDR);
if (error)
break;
if (ifd->ifd_cmd == STF6RD_SV4NET) {
if (ifd->ifd_len != sizeof(args)) {
error = EINVAL;
break;
}
bzero(&args, sizeof(args));
error = copyin(ifd->ifd_data, &args, ifd->ifd_len);
if (error)
break;
if (args.v4_prefixlen < 1 || args.v4_prefixlen > 32) {
error = EINVAL;
break;
}
bcopy(&args.srcv4_addr, &sc_cur->srcv4_addr,
sizeof(sc_cur->srcv4_addr));
sc_cur->v4prefixlen = args.v4_prefixlen;
SDT_PROBE3(if_stf, , ioctl, sv4net, sc_cur->srcv4_addr,
sc_cur->srcv4_addr, sc_cur->v4prefixlen);
} else if (ifd->ifd_cmd == STF6RD_SBR) {
if (ifd->ifd_len != sizeof(args)) {
error = EINVAL;
break;
}
bzero(&args, sizeof(args));
error = copyin(ifd->ifd_data, &args, ifd->ifd_len);
if (error)
break;
sc_cur->braddr = args.braddr.s_addr;
SDT_PROBE1(if_stf, , ioctl, sdstv4,
sc_cur->braddr);
} else
error = EINVAL;
break;
case SIOCGDRVSPEC:
ifd = (struct ifdrv *)data;
if (ifd->ifd_cmd != STF6RD_GV4NET) {
error = EINVAL;
break;
}
if (ifd->ifd_len != sizeof(args)) {
error = EINVAL;
break;
}
bzero(&args, sizeof(args));
args.srcv4_addr.s_addr = sc_cur->srcv4_addr;
args.braddr.s_addr = sc_cur->braddr;
args.v4_prefixlen = sc_cur->v4prefixlen;
error = copyout(&args, ifd->ifd_data, ifd->ifd_len);
break;
case SIOCSIFADDR:
ifa = (struct ifaddr *)data;
SDT_PROBE1(if_stf, , ioctl, ifaddr, ifa);
if (ifa == NULL || ifa->ifa_addr->sa_family != AF_INET6) {
error = EAFNOSUPPORT;
break;
}
if (stf_getin4addr(sc_cur, &sin4,
satosin6(ifa->ifa_addr)->sin6_addr,
satosin6(ifa->ifa_netmask)->sin6_addr) == NULL) {
error = EINVAL;
break;
}
ifp->if_flags |= IFF_UP;
ifp->if_drv_flags |= IFF_DRV_RUNNING;
break;
case SIOCADDMULTI:
case SIOCDELMULTI:
ifr = (struct ifreq *)data;
if (ifr && ifr->ifr_addr.sa_family == AF_INET6)
;
else
error = EAFNOSUPPORT;
break;
case SIOCGIFMTU:
break;
case SIOCSIFMTU:
ifr = (struct ifreq *)data;
mtu = ifr->ifr_mtu;
/* RFC 4213 3.2 ideal world MTU */
if (mtu < IPV6_MINMTU || mtu > IF_MAXMTU - 20)
return (EINVAL);
ifp->if_mtu = mtu;
break;
default:
error = EINVAL;
break;
}
return (error);
}