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sys/netpfil/ipfw/nat64/nat64_translate.c
- This file was added.
/*- | |||||
* Copyright (c) 2015-2016 Yandex LLC | |||||
* Copyright (c) 2015-2016 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. | |||||
* | |||||
* 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 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. | |||||
*/ | |||||
#include "opt_ipfw.h" | |||||
#include <sys/cdefs.h> | |||||
__FBSDID("$FreeBSD$"); | |||||
#include <sys/param.h> | |||||
#include <sys/systm.h> | |||||
#include <sys/counter.h> | |||||
#include <sys/errno.h> | |||||
#include <sys/kernel.h> | |||||
#include <sys/lock.h> | |||||
#include <sys/mbuf.h> | |||||
#include <sys/module.h> | |||||
#include <sys/rmlock.h> | |||||
#include <sys/rwlock.h> | |||||
#include <sys/socket.h> | |||||
#include <sys/queue.h> | |||||
#include <net/if.h> | |||||
#include <net/if_var.h> | |||||
#include <net/pfil.h> | |||||
#include <net/netisr.h> | |||||
#include <net/route.h> | |||||
#include <netinet/in.h> | |||||
#include <netinet/ip.h> | |||||
#include <netinet/ip_var.h> | |||||
#include <netinet/ip_fw.h> | |||||
#include <netinet/ip6.h> | |||||
#include <netinet/icmp6.h> | |||||
#include <netinet/ip_icmp.h> | |||||
#include <netinet/tcp.h> | |||||
#include <netinet/udp.h> | |||||
#include <netinet6/in6_var.h> | |||||
#include <netinet6/ip6_var.h> | |||||
#include <netpfil/ipfw/ip_fw_private.h> | |||||
#include <netpfil/ipfw/nat64/ip_fw_nat64.h> | |||||
#include <netpfil/ipfw/nat64/nat64_translate.h> | |||||
#include <machine/in_cksum.h> | |||||
#ifdef IPFIREWALL_NAT64_DIRECT_OUTPUT | |||||
static __noinline struct sockaddr* nat64_find_route4(struct route *ro, | |||||
in_addr_t dest, struct mbuf *m); | |||||
static __noinline struct sockaddr* nat64_find_route6(struct route_in6 *ro, | |||||
struct in6_addr *dest, struct mbuf *m); | |||||
static __noinline int | |||||
nat64_output(struct ifnet *ifp, struct mbuf *m, | |||||
struct sockaddr *dst, struct route *ro, nat64_stats_block *stats) | |||||
{ | |||||
int error; | |||||
error = (*ifp->if_output)(ifp, m, dst, ro); | |||||
if (error != 0) | |||||
NAT64STAT_INC(stats, oerrors); | |||||
return (error); | |||||
} | |||||
static __noinline int | |||||
nat64_output_one(struct mbuf *m, nat64_stats_block *stats) | |||||
{ | |||||
struct route_in6 ro6; | |||||
struct route ro4, *ro; | |||||
struct sockaddr *dst; | |||||
struct ifnet *ifp; | |||||
struct ip6_hdr *ip6; | |||||
struct ip *ip4; | |||||
int error; | |||||
ip4 = mtod(m, struct ip *); | |||||
switch (ip4->ip_v) { | |||||
case IPVERSION: | |||||
ro = &ro4; | |||||
dst = nat64_find_route4(&ro4, ip4->ip_dst.s_addr, m); | |||||
if (dst == NULL) | |||||
NAT64STAT_INC(stats, noroute4); | |||||
break; | |||||
case (IPV6_VERSION >> 4): | |||||
ip6 = (struct ip6_hdr *)ip4; | |||||
ro = (struct route *)&ro6; | |||||
dst = nat64_find_route6(&ro6, &ip6->ip6_dst, m); | |||||
if (dst == NULL) | |||||
NAT64STAT_INC(stats, noroute6); | |||||
break; | |||||
default: | |||||
m_freem(m); | |||||
NAT64STAT_INC(stats, dropped); | |||||
return (EAFNOSUPPORT); | |||||
} | |||||
if (dst == NULL) { | |||||
FREE_ROUTE(ro); | |||||
m_freem(m); | |||||
return (EHOSTUNREACH); | |||||
} | |||||
ifp = ro->ro_rt->rt_ifp; | |||||
error = (*ifp->if_output)(ifp, m, dst, ro); | |||||
if (error != 0) | |||||
NAT64STAT_INC(stats, oerrors); | |||||
FREE_ROUTE(ro); | |||||
return (error); | |||||
} | |||||
#else /* !IPFIREWALL_NAT64_DIRECT_OUTPUT */ | |||||
static __noinline int | |||||
nat64_output(struct ifnet *ifp, struct mbuf *m, | |||||
struct sockaddr *dst, struct route *ro, nat64_stats_block *stats) | |||||
{ | |||||
struct ip *ip4; | |||||
int ret; | |||||
ip4 = mtod(m, struct ip *); | |||||
switch (ip4->ip_v) { | |||||
case IPVERSION: | |||||
ret = NETISR_IP; | |||||
break; | |||||
case (IPV6_VERSION >> 4): | |||||
ret = NETISR_IPV6; | |||||
break; | |||||
default: | |||||
m_freem(m); | |||||
NAT64STAT_INC(stats, dropped); | |||||
return (EAFNOSUPPORT); | |||||
} | |||||
ret = netisr_queue(ret, m); | |||||
if (ret != 0) | |||||
NAT64STAT_INC(stats, oerrors); | |||||
return (ret); | |||||
} | |||||
static __noinline int | |||||
nat64_output_one(struct mbuf *m, nat64_stats_block *stats) | |||||
{ | |||||
return (nat64_output(NULL, m, NULL, NULL, stats)); | |||||
} | |||||
#endif /* !IPFIREWALL_NAT64_DIRECT_OUTPUT */ | |||||
#if 0 | |||||
void print_ipv6_header(struct ip6_hdr *ip6, char *buf, size_t bufsize); | |||||
void | |||||
print_ipv6_header(struct ip6_hdr *ip6, char *buf, size_t bufsize) | |||||
{ | |||||
char sbuf[INET6_ADDRSTRLEN], dbuf[INET6_ADDRSTRLEN]; | |||||
inet_ntop(AF_INET6, &ip6->ip6_src, sbuf, sizeof(sbuf)); | |||||
inet_ntop(AF_INET6, &ip6->ip6_dst, dbuf, sizeof(dbuf)); | |||||
snprintf(buf, bufsize, "%s -> %s %d", sbuf, dbuf, ip6->ip6_nxt); | |||||
} | |||||
static __noinline int | |||||
nat64_embed_ip4(struct nat64_cfg *cfg, in_addr_t ia, struct in6_addr *ip6) | |||||
{ | |||||
/* assume the prefix is properly filled with zeros */ | |||||
bcopy(&cfg->prefix, ip6, sizeof(*ip6)); | |||||
switch (cfg->plen) { | |||||
case 32: | |||||
case 96: | |||||
ip6->s6_addr32[cfg->plen / 32] = ia; | |||||
break; | |||||
case 40: | |||||
case 48: | |||||
case 56: | |||||
#if BYTE_ORDER == BIG_ENDIAN | |||||
ip6->s6_addr32[1] = cfg->prefix.s6_addr32[1] | | |||||
(ia >> (cfg->plen % 32)); | |||||
ip6->s6_addr32[2] = ia << (24 - cfg->plen % 32); | |||||
#elif BYTE_ORDER == LITTLE_ENDIAN | |||||
ip6->s6_addr32[1] = cfg->prefix.s6_addr32[1] | | |||||
(ia << (cfg->plen % 32)); | |||||
ip6->s6_addr32[2] = ia >> (24 - cfg->plen % 32); | |||||
#endif | |||||
break; | |||||
case 64: | |||||
#if BYTE_ORDER == BIG_ENDIAN | |||||
ip6->s6_addr32[2] = ia >> 8; | |||||
ip6->s6_addr32[3] = ia << 24; | |||||
#elif BYTE_ORDER == LITTLE_ENDIAN | |||||
ip6->s6_addr32[2] = ia << 8; | |||||
ip6->s6_addr32[3] = ia >> 24; | |||||
#endif | |||||
break; | |||||
default: | |||||
return (0); | |||||
}; | |||||
ip6->s6_addr8[8] = 0; | |||||
return (1); | |||||
} | |||||
static __noinline in_addr_t | |||||
nat64_extract_ip4(struct in6_addr *ip6, int plen) | |||||
{ | |||||
in_addr_t ia; | |||||
/* | |||||
* According to RFC 6052 p2.2: | |||||
* IPv4-embedded IPv6 addresses are composed of a variable-length | |||||
* prefix, the embedded IPv4 address, and a variable length suffix. | |||||
* The suffix bits are reserved for future extensions and SHOULD | |||||
* be set to zero. | |||||
*/ | |||||
switch (plen) { | |||||
case 32: | |||||
if (ip6->s6_addr32[3] != 0 || ip6->s6_addr32[2] != 0) | |||||
goto badip6; | |||||
break; | |||||
case 40: | |||||
if (ip6->s6_addr32[3] != 0 || | |||||
(ip6->s6_addr32[2] & htonl(0xff00ffff)) != 0) | |||||
goto badip6; | |||||
break; | |||||
case 48: | |||||
if (ip6->s6_addr32[3] != 0 || | |||||
(ip6->s6_addr32[2] & htonl(0xff0000ff)) != 0) | |||||
goto badip6; | |||||
break; | |||||
case 56: | |||||
if (ip6->s6_addr32[3] != 0 || ip6->s6_addr8[8] != 0) | |||||
goto badip6; | |||||
break; | |||||
case 64: | |||||
if (ip6->s6_addr8[8] != 0 || | |||||
(ip6->s6_addr32[3] & htonl(0x00ffffff)) != 0) | |||||
goto badip6; | |||||
}; | |||||
switch (plen) { | |||||
case 32: | |||||
case 96: | |||||
ia = ip6->s6_addr32[plen / 32]; | |||||
break; | |||||
case 40: | |||||
case 48: | |||||
case 56: | |||||
#if BYTE_ORDER == BIG_ENDIAN | |||||
ia = (ip6->s6_addr32[1] << (plen % 32)) | | |||||
(ip6->s6_addr32[2] >> (24 - plen % 32)); | |||||
#elif BYTE_ORDER == LITTLE_ENDIAN | |||||
ia = (ip6->s6_addr32[1] >> (plen % 32)) | | |||||
(ip6->s6_addr32[2] << (24 - plen % 32)); | |||||
#endif | |||||
break; | |||||
case 64: | |||||
#if BYTE_ORDER == BIG_ENDIAN | |||||
ia = (ip6->s6_addr32[2] << 8) | (ip6->s6_addr32[3] >> 24); | |||||
#elif BYTE_ORDER == LITTLE_ENDIAN | |||||
ia = (ip6->s6_addr32[2] >> 8) | (ip6->s6_addr32[3] << 24); | |||||
#endif | |||||
break; | |||||
default: | |||||
return (0); | |||||
}; | |||||
if (nat64_check_ip4(ia) != 0 || | |||||
nat64_check_private_ip4(ia) != 0) | |||||
goto badip4; | |||||
return (ia); | |||||
badip4: | |||||
DPRINTF("invalid destination address: %08x", ia); | |||||
return (0); | |||||
badip6: | |||||
DPRINTF("invalid IPv4-embedded IPv6 address"); | |||||
return (0); | |||||
} | |||||
#endif | |||||
/* | |||||
* According to RFC 1624 the equation for incremental checksum update is: | |||||
* HC' = ~(~HC + ~m + m') -- [Eqn. 3] | |||||
* HC' = HC - ~m - m' -- [Eqn. 4] | |||||
* So, when we are replacing IPv4 addresses to IPv6, we | |||||
* can assume, that new bytes previously were zeros, and vise versa - | |||||
* when we replacing IPv6 addresses to IPv4, now unused bytes become | |||||
* zeros. The payload length in pseudo header has bigger size, but one | |||||
* half of it should be zero. Using the equation 4 we get: | |||||
* HC' = HC - (~m0 + m0') -- m0 is first changed word | |||||
* HC' = (HC - (~m0 + m0')) - (~m1 + m1') -- m1 is second changed word | |||||
* HC' = HC - ~m0 - m0' - ~m1 - m1' - ... = | |||||
* = HC - sum(~m[i] + m'[i]) | |||||
* | |||||
* The function result should be used as follows: | |||||
* IPv6 to IPv4: HC' = cksum_add(HC, result) | |||||
* IPv4 to IPv6: HC' = cksum_add(HC, ~result) | |||||
*/ | |||||
static __noinline uint16_t | |||||
nat64_cksum_convert(struct ip6_hdr *ip6, struct ip *ip) | |||||
{ | |||||
uint32_t sum; | |||||
uint16_t *p; | |||||
sum = ~ip->ip_src.s_addr >> 16; | |||||
sum += ~ip->ip_src.s_addr & 0xffff; | |||||
sum += ~ip->ip_dst.s_addr >> 16; | |||||
sum += ~ip->ip_dst.s_addr & 0xffff; | |||||
for (p = (uint16_t *)&ip6->ip6_src; | |||||
p < (uint16_t *)(&ip6->ip6_src + 2); p++) | |||||
sum += *p; | |||||
while (sum >> 16) | |||||
sum = (sum & 0xffff) + (sum >> 16); | |||||
return (sum); | |||||
} | |||||
#if __FreeBSD_version < 1100000 | |||||
#define ip_fillid(ip) (ip)->ip_id = ip_newid() | |||||
#endif | |||||
static __noinline void | |||||
nat64_init_ip4hdr(const struct ip6_hdr *ip6, const struct ip6_frag *frag, | |||||
uint16_t plen, uint8_t proto, struct ip *ip) | |||||
{ | |||||
/* assume addresses are already initialized */ | |||||
ip->ip_v = IPVERSION; | |||||
ip->ip_hl = sizeof(*ip) >> 2; | |||||
ip->ip_tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff; | |||||
ip->ip_len = htons(sizeof(*ip) + plen); | |||||
ip->ip_ttl = ip6->ip6_hlim - IPV6_HLIMDEC; | |||||
ip->ip_sum = 0; | |||||
ip->ip_p = (proto == IPPROTO_ICMPV6) ? IPPROTO_ICMP: proto; | |||||
ip_fillid(ip); | |||||
if (frag != NULL) { | |||||
ip->ip_off = htons(ntohs(frag->ip6f_offlg) >> 3); | |||||
if (frag->ip6f_offlg & IP6F_MORE_FRAG) | |||||
ip->ip_off |= htons(IP_MF); | |||||
} else { | |||||
ip->ip_off = htons(IP_DF); | |||||
} | |||||
ip->ip_sum = in_cksum_hdr(ip); | |||||
} | |||||
#define FRAGSZ(mtu) ((mtu) - sizeof(struct ip6_hdr) - sizeof(struct ip6_frag)) | |||||
static __noinline int | |||||
nat64_fragment6(nat64_stats_block *stats, struct ip6_hdr *ip6, struct mbufq *mq, | |||||
struct mbuf *m, uint32_t mtu, uint16_t ip_id, uint16_t ip_off) | |||||
{ | |||||
struct ip6_frag ip6f; | |||||
struct mbuf *n; | |||||
uint16_t hlen, len, offset; | |||||
int plen; | |||||
plen = ntohs(ip6->ip6_plen); | |||||
hlen = sizeof(struct ip6_hdr); | |||||
/* Fragmentation isn't needed */ | |||||
if (ip_off == 0 && plen <= mtu - hlen) { | |||||
M_PREPEND(m, hlen, M_NOWAIT); | |||||
if (m == NULL) { | |||||
NAT64STAT_INC(stats, nomem); | |||||
return (ENOMEM); | |||||
} | |||||
bcopy(ip6, mtod(m, void *), hlen); | |||||
if (mbufq_enqueue(mq, m) != 0) { | |||||
m_freem(m); | |||||
NAT64STAT_INC(stats, dropped); | |||||
return (ENOBUFS); | |||||
} | |||||
return (0); | |||||
} | |||||
hlen += sizeof(struct ip6_frag); | |||||
ip6f.ip6f_reserved = 0; | |||||
ip6f.ip6f_nxt = ip6->ip6_nxt; | |||||
ip6->ip6_nxt = IPPROTO_FRAGMENT; | |||||
if (ip_off != 0) { | |||||
/* | |||||
* We have got an IPv4 fragment. | |||||
* Use offset value and ip_id from original fragment. | |||||
*/ | |||||
ip6f.ip6f_ident = htonl(ntohs(ip_id)); | |||||
offset = (ntohs(ip_off) & IP_OFFMASK) << 3; | |||||
NAT64STAT_INC(stats, ifrags); | |||||
} else { | |||||
/* The packet size exceeds interface MTU */ | |||||
ip6f.ip6f_ident = htonl(ip6_randomid()); | |||||
offset = 0; /* First fragment*/ | |||||
} | |||||
while (plen > 0 && m != NULL) { | |||||
n = NULL; | |||||
len = FRAGSZ(mtu) & ~7; | |||||
if (len > plen) | |||||
len = plen; | |||||
ip6->ip6_plen = htons(len + sizeof(ip6f)); | |||||
ip6f.ip6f_offlg = ntohs(offset); | |||||
if (len < plen || (ip_off & htons(IP_MF)) != 0) | |||||
ip6f.ip6f_offlg |= IP6F_MORE_FRAG; | |||||
offset += len; | |||||
plen -= len; | |||||
if (plen > 0) { | |||||
n = m_split(m, len, M_NOWAIT); | |||||
if (n == NULL) | |||||
goto fail; | |||||
} | |||||
M_PREPEND(m, hlen, M_NOWAIT); | |||||
if (m == NULL) | |||||
goto fail; | |||||
bcopy(ip6, mtod(m, void *), sizeof(struct ip6_hdr)); | |||||
bcopy(&ip6f, mtodo(m, sizeof(struct ip6_hdr)), | |||||
sizeof(struct ip6_frag)); | |||||
if (mbufq_enqueue(mq, m) != 0) | |||||
goto fail; | |||||
m = n; | |||||
} | |||||
NAT64STAT_ADD(stats, ofrags, mbufq_len(mq)); | |||||
return (0); | |||||
fail: | |||||
if (m != NULL) | |||||
m_freem(m); | |||||
if (n != NULL) | |||||
m_freem(n); | |||||
mbufq_drain(mq); | |||||
NAT64STAT_INC(stats, nomem); | |||||
return (ENOMEM); | |||||
} | |||||
#if __FreeBSD_version < 1100000 | |||||
#define rt_expire rt_rmx.rmx_expire | |||||
#define rt_mtu rt_rmx.rmx_mtu | |||||
#endif | |||||
static __noinline struct sockaddr* | |||||
nat64_find_route6(struct route_in6 *ro, struct in6_addr *dest, struct mbuf *m) | |||||
{ | |||||
struct sockaddr_in6 *dst; | |||||
struct rtentry *rt; | |||||
bzero(ro, sizeof(*ro)); | |||||
dst = (struct sockaddr_in6 *)&ro->ro_dst; | |||||
dst->sin6_family = AF_INET6; | |||||
dst->sin6_len = sizeof(*dst); | |||||
dst->sin6_addr = *dest; | |||||
IN6_LOOKUP_ROUTE(ro, M_GETFIB(m)); | |||||
rt = ro->ro_rt; | |||||
if (rt && (rt->rt_flags & RTF_UP) && | |||||
(rt->rt_ifp->if_flags & IFF_UP) && | |||||
(rt->rt_ifp->if_drv_flags & IFF_DRV_RUNNING)) { | |||||
if (rt->rt_flags & RTF_GATEWAY) | |||||
dst = (struct sockaddr_in6 *)rt->rt_gateway; | |||||
} else | |||||
return (NULL); | |||||
if (((rt->rt_flags & RTF_REJECT) && | |||||
(rt->rt_expire == 0 || | |||||
time_uptime < rt->rt_expire)) || | |||||
rt->rt_ifp->if_link_state == LINK_STATE_DOWN) | |||||
return (NULL); | |||||
return ((struct sockaddr *)dst); | |||||
} | |||||
#define NAT64_ICMP6_PLEN 64 | |||||
static __noinline void | |||||
nat64_icmp6_reflect(struct mbuf *m, uint8_t type, uint8_t code, uint32_t mtu, | |||||
nat64_stats_block *stats) | |||||
{ | |||||
struct icmp6_hdr *icmp6; | |||||
struct ip6_hdr *ip6, *oip6; | |||||
struct mbuf *n; | |||||
int len, plen; | |||||
ip6 = mtod(m, struct ip6_hdr *); | |||||
if (ip6->ip6_nxt == IPPROTO_ICMPV6) | |||||
goto freeit; | |||||
/* | |||||
if (icmp6_ratelimit(&ip6->ip6_src, type, code)) | |||||
goto freeit; | |||||
*/ | |||||
switch (type) { | |||||
case ICMP6_DST_UNREACH: | |||||
case ICMP6_PACKET_TOO_BIG: | |||||
case ICMP6_TIME_EXCEEDED: | |||||
case ICMP6_PARAM_PROB: | |||||
break; | |||||
default: | |||||
goto freeit; | |||||
} | |||||
/* Calculate length of ICMPv6 payload */ | |||||
len = (m->m_pkthdr.len > NAT64_ICMP6_PLEN) ? NAT64_ICMP6_PLEN: | |||||
m->m_pkthdr.len; | |||||
/* Create new ICMPv6 datagram */ | |||||
plen = len + sizeof(struct icmp6_hdr); | |||||
n = m_get2(sizeof(struct ip6_hdr) + plen + max_hdr, M_NOWAIT, | |||||
MT_HEADER, M_PKTHDR); | |||||
if (n == NULL) { | |||||
NAT64STAT_INC(stats, nomem); | |||||
m_freem(m); | |||||
return; | |||||
} | |||||
/* | |||||
* Move pkthdr from original mbuf. We should have initialized some | |||||
* fields, because we can reinject this mbuf to netisr and it will | |||||
* go trough input path (it requires at least rcvif should be set). | |||||
* Also do M_ALIGN() to reduce chances of need to allocate new mbuf | |||||
* in the chain, when we will do M_PREPEND() or make some type of | |||||
* tunneling. | |||||
*/ | |||||
m_move_pkthdr(n, m); | |||||
M_ALIGN(n, sizeof(struct ip6_hdr) + plen + max_hdr); | |||||
n->m_len = n->m_pkthdr.len = sizeof(struct ip6_hdr) + plen; | |||||
oip6 = mtod(n, struct ip6_hdr *); | |||||
oip6->ip6_src = ip6->ip6_dst; | |||||
oip6->ip6_dst = ip6->ip6_src; | |||||
oip6->ip6_nxt = IPPROTO_ICMPV6; | |||||
oip6->ip6_flow = 0; | |||||
oip6->ip6_vfc |= IPV6_VERSION; | |||||
oip6->ip6_hlim = V_ip6_defhlim; | |||||
oip6->ip6_plen = htons(plen); | |||||
icmp6 = mtodo(n, sizeof(struct ip6_hdr)); | |||||
icmp6->icmp6_cksum = 0; | |||||
icmp6->icmp6_type = type; | |||||
icmp6->icmp6_code = code; | |||||
icmp6->icmp6_mtu = htonl(mtu); | |||||
m_copydata(m, 0, len, mtodo(n, sizeof(struct ip6_hdr) + | |||||
sizeof(struct icmp6_hdr))); | |||||
icmp6->icmp6_cksum = in6_cksum(n, IPPROTO_ICMPV6, | |||||
sizeof(struct ip6_hdr), plen); | |||||
m_freem(m); | |||||
nat64_output_one(n, stats); | |||||
return; | |||||
freeit: | |||||
NAT64STAT_INC(stats, dropped); | |||||
m_freem(m); | |||||
} | |||||
static __noinline struct sockaddr* | |||||
nat64_find_route4(struct route *ro, in_addr_t dest, struct mbuf *m) | |||||
{ | |||||
struct sockaddr_in *dst; | |||||
struct rtentry *rt; | |||||
bzero(ro, sizeof(*ro)); | |||||
dst = (struct sockaddr_in *)&ro->ro_dst; | |||||
dst->sin_family = AF_INET; | |||||
dst->sin_len = sizeof(*dst); | |||||
dst->sin_addr.s_addr = dest; | |||||
IN_LOOKUP_ROUTE(ro, M_GETFIB(m)); | |||||
rt = ro->ro_rt; | |||||
if (rt && (rt->rt_flags & RTF_UP) && | |||||
(rt->rt_ifp->if_flags & IFF_UP) && | |||||
(rt->rt_ifp->if_drv_flags & IFF_DRV_RUNNING)) { | |||||
if (rt->rt_flags & RTF_GATEWAY) | |||||
dst = (struct sockaddr_in *)rt->rt_gateway; | |||||
} else | |||||
return (NULL); | |||||
if (((rt->rt_flags & RTF_REJECT) && | |||||
(rt->rt_expire == 0 || | |||||
time_uptime < rt->rt_expire)) || | |||||
rt->rt_ifp->if_link_state == LINK_STATE_DOWN) | |||||
return (NULL); | |||||
return ((struct sockaddr *)dst); | |||||
} | |||||
#define NAT64_ICMP_PLEN 64 | |||||
static __noinline void | |||||
nat64_icmp_reflect(struct mbuf *m, uint8_t type, | |||||
uint8_t code, uint16_t mtu, nat64_stats_block *stats) | |||||
{ | |||||
struct icmp *icmp; | |||||
struct ip *ip, *oip; | |||||
struct mbuf *n; | |||||
int len, plen; | |||||
ip = mtod(m, struct ip *); | |||||
if (ip->ip_p == IPPROTO_ICMP || (ip->ip_off & ~ntohs(IP_MF|IP_DF))) | |||||
goto freeit; | |||||
switch (type) { | |||||
case ICMP_UNREACH: | |||||
case ICMP_TIMXCEED: | |||||
case ICMP_PARAMPROB: | |||||
break; | |||||
default: | |||||
goto freeit; | |||||
} | |||||
/* Calculate length of ICMP payload */ | |||||
len = (m->m_pkthdr.len > NAT64_ICMP_PLEN) ? (ip->ip_hl << 2) + 8: | |||||
m->m_pkthdr.len; | |||||
/* Create new ICMPv4 datagram */ | |||||
plen = len + sizeof(struct icmphdr) + sizeof(uint32_t); | |||||
n = m_get2(sizeof(struct ip) + plen + max_hdr, M_NOWAIT, | |||||
MT_HEADER, M_PKTHDR); | |||||
if (n == NULL) { | |||||
NAT64STAT_INC(stats, nomem); | |||||
m_freem(m); | |||||
return; | |||||
} | |||||
m_move_pkthdr(n, m); | |||||
M_ALIGN(n, sizeof(struct ip) + plen + max_hdr); | |||||
n->m_len = n->m_pkthdr.len = sizeof(struct ip) + plen; | |||||
oip = mtod(n, struct ip *); | |||||
oip->ip_v = IPVERSION; | |||||
oip->ip_hl = sizeof(struct ip) >> 2; | |||||
oip->ip_tos = 0; | |||||
oip->ip_len = htons(n->m_pkthdr.len); | |||||
oip->ip_ttl = V_ip_defttl; | |||||
oip->ip_p = IPPROTO_ICMP; | |||||
ip_fillid(oip); | |||||
oip->ip_off = htons(IP_DF); | |||||
oip->ip_src = ip->ip_dst; | |||||
oip->ip_dst = ip->ip_src; | |||||
oip->ip_sum = 0; | |||||
oip->ip_sum = in_cksum_hdr(oip); | |||||
icmp = mtodo(n, sizeof(struct ip)); | |||||
icmp->icmp_type = type; | |||||
icmp->icmp_code = code; | |||||
icmp->icmp_cksum = 0; | |||||
icmp->icmp_pmvoid = 0; | |||||
icmp->icmp_nextmtu = htons(mtu); | |||||
m_copydata(m, 0, len, mtodo(n, sizeof(struct ip) + | |||||
sizeof(struct icmphdr) + sizeof(uint32_t))); | |||||
icmp->icmp_cksum = in_cksum_skip(n, sizeof(struct ip) + plen, | |||||
sizeof(struct ip)); | |||||
m_freem(m); | |||||
nat64_output_one(n, stats); | |||||
return; | |||||
freeit: | |||||
NAT64STAT_INC(stats, dropped); | |||||
m_freem(m); | |||||
} | |||||
/* Translate ICMP echo request/reply into ICMPv6 */ | |||||
static void | |||||
nat64_icmp_handle_echo(struct ip6_hdr *ip6, struct icmp6_hdr *icmp6, | |||||
uint16_t id, uint8_t type) | |||||
{ | |||||
uint16_t old; | |||||
old = *(uint16_t *)icmp6; /* save type+code in one word */ | |||||
icmp6->icmp6_type = type; | |||||
/* Reflect ICMPv6 -> ICMPv4 type translation in the cksum */ | |||||
icmp6->icmp6_cksum = cksum_adjust(icmp6->icmp6_cksum, | |||||
old, *(uint16_t *)icmp6); | |||||
if (id != 0) { | |||||
old = icmp6->icmp6_id; | |||||
icmp6->icmp6_id = id; | |||||
/* Reflect ICMP id translation in the cksum */ | |||||
icmp6->icmp6_cksum = cksum_adjust(icmp6->icmp6_cksum, | |||||
old, id); | |||||
} | |||||
/* Reflect IPv6 pseudo header in the cksum */ | |||||
icmp6->icmp6_cksum = ~in6_cksum_pseudo(ip6, ntohs(ip6->ip6_plen), | |||||
IPPROTO_ICMPV6, ~icmp6->icmp6_cksum); | |||||
} | |||||
static __noinline struct mbuf * | |||||
nat64_icmp_translate(struct mbuf *m, struct ip6_hdr *ip6, uint16_t icmpid, | |||||
int offset, nat64_stats_block *stats) | |||||
{ | |||||
struct ip ip; | |||||
struct icmp *icmp; | |||||
struct ip6_hdr *eip6; | |||||
struct mbuf *n; | |||||
uint32_t mtu; | |||||
int len, hlen, plen; | |||||
uint8_t type, code; | |||||
if (m->m_len < offset + ICMP_MINLEN) | |||||
m = m_pullup(m, offset + ICMP_MINLEN); | |||||
if (m == NULL) { | |||||
NAT64STAT_INC(stats, nomem); | |||||
return (m); | |||||
} | |||||
mtu = 0; | |||||
icmp = mtodo(m, offset); | |||||
switch (icmp->icmp_type) { | |||||
case ICMP_ECHOREPLY: | |||||
type = ICMP6_ECHO_REPLY; | |||||
code = 0; | |||||
break; | |||||
case ICMP_UNREACH: | |||||
type = ICMP6_DST_UNREACH; | |||||
switch (icmp->icmp_code) { | |||||
case ICMP_UNREACH_HOST: | |||||
code = ICMP6_DST_UNREACH_NOROUTE; | |||||
break; | |||||
case ICMP_UNREACH_PROTOCOL: | |||||
type = ICMP6_PARAM_PROB; | |||||
code = ICMP6_PARAMPROB_NEXTHEADER; | |||||
break; | |||||
case ICMP_UNREACH_PORT: | |||||
code = ICMP6_DST_UNREACH_NOPORT; | |||||
break; | |||||
case ICMP_UNREACH_NEEDFRAG: | |||||
code = 0; | |||||
type = ICMP6_PACKET_TOO_BIG; | |||||
mtu = ntohs(icmp->icmp_nextmtu); | |||||
break; | |||||
case ICMP_UNREACH_FILTER_PROHIB: | |||||
code = ICMP6_DST_UNREACH_ADMIN; | |||||
break; | |||||
default: | |||||
goto freeit; | |||||
} | |||||
break; | |||||
case ICMP_TIMXCEED: | |||||
type = ICMP6_TIME_EXCEEDED; | |||||
code = icmp->icmp_code; | |||||
break; | |||||
case ICMP_ECHO: | |||||
type = ICMP6_ECHO_REQUEST; | |||||
code = 0; | |||||
break; | |||||
default: | |||||
DPRINTF("Unsupported ICMP type %d", icmp->icmp_type); | |||||
goto freeit; | |||||
} | |||||
/* | |||||
* For echo request/reply we can use original payload, | |||||
* but we need adjust icmp_cksum, because ICMPv6 cksum covers | |||||
* IPv6 pseudo header and ICMPv6 types differs from ICMPv4. | |||||
*/ | |||||
if (type == ICMP6_ECHO_REQUEST || type == ICMP6_ECHO_REPLY) { | |||||
nat64_icmp_handle_echo(ip6, ICMP6(icmp), icmpid, type); | |||||
return (m); | |||||
} | |||||
/* | |||||
* For other types of ICMP messages we need to translate inner | |||||
* IPv4 header to IPv6 header. | |||||
* Assume ICMP src is the same as payload dst | |||||
* E.g. we have ( GWsrc1 , NATIP1 ) in outer header | |||||
* and ( NATIP1, Hostdst1 ) in ICMP copy header. | |||||
* In that case, we already have map for NATIP1 and GWsrc1. | |||||
* The only thing we need is to copy IPv6 map prefix to | |||||
* Hostdst1. | |||||
*/ | |||||
hlen = offset + ICMP_MINLEN; | |||||
if (m->m_pkthdr.len < hlen + sizeof(struct ip) + ICMP_MINLEN) { | |||||
DPRINTF("Message is too short %d", m->m_pkthdr.len); | |||||
goto freeit; | |||||
} | |||||
m_copydata(m, hlen, sizeof(struct ip), (char *)&ip); | |||||
if (ip.ip_v != IPVERSION) { | |||||
DPRINTF("Wrong IP version %d", ip.ip_v); | |||||
goto freeit; | |||||
} | |||||
hlen += ip.ip_hl << 2; /* Skip inner IP header */ | |||||
if (nat64_check_ip4(ip.ip_src.s_addr) != 0 || | |||||
nat64_check_ip4(ip.ip_dst.s_addr) != 0 || | |||||
nat64_check_private_ip4(ip.ip_src.s_addr) != 0 || | |||||
nat64_check_private_ip4(ip.ip_dst.s_addr) != 0) { | |||||
DPRINTF("IP addresses checks failed %04x -> %04x", | |||||
ip.ip_src.s_addr, ip.ip_dst.s_addr); | |||||
goto freeit; | |||||
} | |||||
if (m->m_pkthdr.len < hlen + ICMP_MINLEN) { | |||||
DPRINTF("Message is too short %d", m->m_pkthdr.len); | |||||
goto freeit; | |||||
} | |||||
#if 0 | |||||
/* | |||||
* Check that inner source matches the outer destination. | |||||
* XXX: We need some method to convert IPv4 into IPv6 address here, | |||||
* and compare IPv6 addresses. | |||||
*/ | |||||
if (ip.ip_src.s_addr != nat64_get_ip4(&ip6->ip6_dst)) { | |||||
DPRINTF("Inner source doesn't match destination ", | |||||
"%04x vs %04x", ip.ip_src.s_addr, | |||||
nat64_get_ip4(&ip6->ip6_dst)); | |||||
goto freeit; | |||||
} | |||||
#endif | |||||
/* | |||||
* Create new mbuf for ICMPv6 datagram. | |||||
* NOTE: len is data length just after inner IP header. | |||||
*/ | |||||
len = m->m_pkthdr.len - hlen; | |||||
if (sizeof(struct ip6_hdr) + | |||||
sizeof(struct icmp6_hdr) + len > NAT64_ICMP6_PLEN) | |||||
len = NAT64_ICMP6_PLEN - sizeof(struct icmp6_hdr) - | |||||
sizeof(struct ip6_hdr); | |||||
plen = sizeof(struct icmp6_hdr) + sizeof(struct ip6_hdr) + len; | |||||
n = m_get2(offset + plen + max_hdr, M_NOWAIT, MT_HEADER, M_PKTHDR); | |||||
if (n == NULL) { | |||||
NAT64STAT_INC(stats, nomem); | |||||
m_freem(m); | |||||
return (NULL); | |||||
} | |||||
m_move_pkthdr(n, m); | |||||
M_ALIGN(n, offset + plen + max_hdr); | |||||
n->m_len = n->m_pkthdr.len = offset + plen; | |||||
/* Adjust ip6_plen in outer header */ | |||||
ip6->ip6_plen = htons(plen); | |||||
/* Construct new inner IPv6 header */ | |||||
eip6 = mtodo(n, offset + sizeof(struct icmp6_hdr)); | |||||
eip6->ip6_src = ip6->ip6_dst; | |||||
/* Use the fact that we have single /96 prefix for IPv4 map */ | |||||
eip6->ip6_dst = ip6->ip6_src; | |||||
nat64_set_ip4(&eip6->ip6_dst, ip.ip_dst.s_addr); | |||||
eip6->ip6_flow = htonl(ip.ip_tos << 20); | |||||
eip6->ip6_vfc |= IPV6_VERSION; | |||||
eip6->ip6_hlim = ip.ip_ttl; | |||||
eip6->ip6_plen = htons(ntohs(ip.ip_len) - (ip.ip_hl << 2)); | |||||
eip6->ip6_nxt = (ip.ip_p == IPPROTO_ICMP) ? IPPROTO_ICMPV6: ip.ip_p; | |||||
m_copydata(m, hlen, len, (char *)(eip6 + 1)); | |||||
/* | |||||
* Check if this is an ICMP error message for echo request | |||||
* that we sent. I.e. ULP in the data containing invoking | |||||
* packet is IPPROTO_ICMP and its type is ICMP_ECHO. | |||||
*/ | |||||
if (ip.ip_p == IPPROTO_ICMP) { | |||||
icmp = (struct icmp *)(eip6 + 1); | |||||
if (icmp->icmp_type != ICMP_ECHO) { | |||||
m_freem(n); | |||||
goto freeit; | |||||
} | |||||
/* | |||||
* For our client this original datagram should looks | |||||
* like it was ICMPv6 datagram with type ICMP6_ECHO_REQUEST. | |||||
* Thus we need adjust icmp_cksum and convert type from | |||||
* ICMP_ECHO to ICMP6_ECHO_REQUEST. | |||||
*/ | |||||
nat64_icmp_handle_echo(eip6, ICMP6(icmp), icmpid, | |||||
ICMP6_ECHO_REQUEST); | |||||
} | |||||
m_freem(m); | |||||
/* Convert ICMPv4 into ICMPv6 header */ | |||||
icmp = mtodo(n, offset); | |||||
ICMP6(icmp)->icmp6_type = type; | |||||
ICMP6(icmp)->icmp6_code = code; | |||||
ICMP6(icmp)->icmp6_mtu = htonl(mtu); | |||||
ICMP6(icmp)->icmp6_cksum = 0; | |||||
ICMP6(icmp)->icmp6_cksum = cksum_add( | |||||
~in6_cksum_pseudo(ip6, plen, IPPROTO_ICMPV6, 0), | |||||
in_cksum_skip(n, n->m_pkthdr.len, offset)); | |||||
return (n); | |||||
freeit: | |||||
m_freem(m); | |||||
NAT64STAT_INC(stats, dropped); | |||||
return (NULL); | |||||
} | |||||
int | |||||
nat64_do_handle_ip4(struct mbuf *m, struct in6_addr *saddr, | |||||
struct in6_addr *daddr, uint16_t lport, nat64_stats_block *stats) | |||||
{ | |||||
struct route_in6 ro; | |||||
struct ip6_hdr ip6; | |||||
struct ifnet *ifp; | |||||
struct ip *ip; | |||||
struct mbufq mq; | |||||
struct sockaddr *dst; | |||||
uint32_t mtu; | |||||
uint16_t ip_id, ip_off; | |||||
uint16_t *csum; | |||||
int plen, hlen; | |||||
uint8_t proto; | |||||
ip = mtod(m, struct ip*); | |||||
if (ip->ip_ttl <= IPTTLDEC) { | |||||
nat64_icmp_reflect(m, ICMP_TIMXCEED, | |||||
ICMP_TIMXCEED_INTRANS, 0, stats); | |||||
return (NAT64RETURN); | |||||
} | |||||
ip6.ip6_dst = *daddr; | |||||
ip6.ip6_src = *saddr; | |||||
hlen = ip->ip_hl << 2; | |||||
plen = ntohs(ip->ip_len) - hlen; | |||||
proto = ip->ip_p; | |||||
/* Save ip_id and ip_off, both are in network byte order */ | |||||
ip_id = ip->ip_id; | |||||
ip_off = ip->ip_off & htons(IP_OFFMASK | IP_MF); | |||||
/* Fragment length must be multiple of 8 octets */ | |||||
if ((ip->ip_off & htons(IP_MF)) != 0 && (plen & 0x7) != 0) { | |||||
nat64_icmp_reflect(m, ICMP_PARAMPROB, | |||||
ICMP_PARAMPROB_LENGTH, 0, stats); | |||||
return (NAT64RETURN); | |||||
} | |||||
/* Fragmented ICMP is unsupported */ | |||||
if (proto == IPPROTO_ICMP && ip_off != 0) { | |||||
NAT64STAT_INC(stats, dropped); | |||||
return (NAT64MFREE); | |||||
} | |||||
dst = nat64_find_route6(&ro, &ip6.ip6_dst, m); | |||||
if (dst == NULL) { | |||||
FREE_ROUTE(&ro); | |||||
NAT64STAT_INC(stats, noroute6); | |||||
nat64_icmp_reflect(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, | |||||
stats); | |||||
return (NAT64RETURN); | |||||
} | |||||
ifp = ro.ro_rt->rt_ifp; | |||||
if (ro.ro_rt->rt_mtu != 0) | |||||
mtu = min(ro.ro_rt->rt_mtu, ifp->if_mtu); | |||||
else | |||||
mtu = ifp->if_mtu; | |||||
if (mtu < plen + sizeof(ip6) && (ip->ip_off & htons(IP_DF)) != 0) { | |||||
FREE_ROUTE(&ro); | |||||
nat64_icmp_reflect(m, ICMP_UNREACH, ICMP_UNREACH_NEEDFRAG, | |||||
FRAGSZ(mtu) + sizeof(struct ip), stats); | |||||
return (NAT64RETURN); | |||||
} | |||||
ip6.ip6_flow = htonl(ip->ip_tos << 20); | |||||
ip6.ip6_vfc |= IPV6_VERSION; | |||||
ip6.ip6_hlim = ip->ip_ttl - IPTTLDEC; | |||||
ip6.ip6_plen = htons(plen); | |||||
ip6.ip6_nxt = (proto == IPPROTO_ICMP) ? IPPROTO_ICMPV6: proto; | |||||
/* Convert checksums. */ | |||||
switch (proto) { | |||||
case IPPROTO_TCP: | |||||
csum = &TCP(mtodo(m, hlen))->th_sum; | |||||
if (lport != 0) { | |||||
struct tcphdr *tcp = TCP(mtodo(m, hlen)); | |||||
*csum = cksum_adjust(*csum, tcp->th_dport, lport); | |||||
tcp->th_dport = lport; | |||||
} | |||||
*csum = cksum_add(*csum, ~nat64_cksum_convert(&ip6, ip)); | |||||
break; | |||||
case IPPROTO_UDP: | |||||
csum = &UDP(mtodo(m, hlen))->uh_sum; | |||||
if (lport != 0) { | |||||
struct udphdr *udp = UDP(mtodo(m, hlen)); | |||||
*csum = cksum_adjust(*csum, udp->uh_dport, lport); | |||||
udp->uh_dport = lport; | |||||
} | |||||
*csum = cksum_add(*csum, ~nat64_cksum_convert(&ip6, ip)); | |||||
break; | |||||
case IPPROTO_ICMP: | |||||
m = nat64_icmp_translate(m, &ip6, lport, hlen, stats); | |||||
if (m == NULL) { | |||||
FREE_ROUTE(&ro); | |||||
/* stats already accounted */ | |||||
return (NAT64RETURN); | |||||
} | |||||
} | |||||
m_adj(m, hlen); | |||||
mbufq_init(&mq, 255); | |||||
nat64_fragment6(stats, &ip6, &mq, m, mtu, ip_id, ip_off); | |||||
while ((m = mbufq_dequeue(&mq)) != NULL) { | |||||
if (nat64_output(ifp, m, dst, (struct route *)&ro, stats) != 0) | |||||
break; | |||||
NAT64STAT_INC(stats, opcnt46); | |||||
} | |||||
mbufq_drain(&mq); | |||||
FREE_ROUTE(&ro); | |||||
return (NAT64RETURN); | |||||
} | |||||
int | |||||
nat64_handle_icmp6(struct mbuf *m, int hlen, uint32_t aaddr, uint16_t aport, | |||||
nat64_stats_block *stats) | |||||
{ | |||||
struct ip ip; | |||||
struct icmp6_hdr *icmp6; | |||||
struct ip6_frag *ip6f; | |||||
struct ip6_hbh *hbh; | |||||
struct ip6_hdr *ip6, *ip6i; | |||||
uint32_t mtu; | |||||
int plen; | |||||
uint8_t proto, type, code; | |||||
ip6 = mtod(m, struct ip6_hdr *); | |||||
if (hlen != 0) | |||||
goto translate; | |||||
if (nat64_check_ip6(&ip6->ip6_src) != 0 || | |||||
nat64_check_ip6(&ip6->ip6_dst) != 0) | |||||
return (NAT64SKIP); | |||||
hlen = sizeof(struct ip6_hdr); | |||||
plen = ntohs(ip6->ip6_plen); | |||||
proto = ip6->ip6_nxt; | |||||
/* Skip extension headers */ | |||||
while (proto == IPPROTO_HOPOPTS || proto == IPPROTO_ROUTING || | |||||
proto == IPPROTO_DSTOPTS) { | |||||
hbh = mtodo(m, hlen); | |||||
if (m->m_len < hlen || /* XXX: m_pullup problem */ | |||||
(plen == 0 && proto == IPPROTO_HOPOPTS)) { | |||||
/* XXX: jumbo payload option */ | |||||
NAT64STAT_INC(stats, dropped); | |||||
return (NAT64MFREE); | |||||
} | |||||
proto = hbh->ip6h_nxt; | |||||
hlen += hbh->ip6h_len << 3; | |||||
} | |||||
if (proto != IPPROTO_ICMPV6) { | |||||
NAT64STAT_INC(stats, dropped); | |||||
return (NAT64MFREE); | |||||
} | |||||
translate: | |||||
/* Translate ICMPv6 type and code to ICMPv4 */ | |||||
icmp6 = mtodo(m, hlen); | |||||
mtu = 0; | |||||
switch (icmp6->icmp6_type) { | |||||
case ICMP6_DST_UNREACH: | |||||
type = ICMP_UNREACH; | |||||
switch (icmp6->icmp6_code) { | |||||
case ICMP6_DST_UNREACH_NOROUTE: | |||||
case ICMP6_DST_UNREACH_BEYONDSCOPE: | |||||
case ICMP6_DST_UNREACH_ADDR: | |||||
code = ICMP_UNREACH_HOST; | |||||
break; | |||||
case ICMP6_DST_UNREACH_ADMIN: | |||||
code = ICMP_UNREACH_FILTER_PROHIB; | |||||
break; | |||||
case ICMP6_DST_UNREACH_NOPORT: | |||||
code = ICMP_UNREACH_PORT; | |||||
break; | |||||
default: | |||||
NAT64STAT_INC(stats, dropped); | |||||
return (NAT64MFREE); | |||||
} | |||||
break; | |||||
case ICMP6_PACKET_TOO_BIG: | |||||
type = ICMP_UNREACH; | |||||
code = ICMP_UNREACH_NEEDFRAG; | |||||
mtu = ntohl(icmp6->icmp6_mtu); | |||||
if (mtu < 576) | |||||
return (NAT64MFREE); | |||||
mtu -= sizeof(struct ip6_hdr) + sizeof(struct ip); | |||||
break; | |||||
case ICMP6_TIME_EXCEED_TRANSIT: | |||||
type = ICMP_TIMXCEED; | |||||
code = ICMP_TIMXCEED_INTRANS; | |||||
break; | |||||
case ICMP6_PARAM_PROB: | |||||
if (icmp6->icmp6_code == ICMP6_PARAMPROB_NEXTHEADER) { | |||||
type = ICMP_UNREACH; | |||||
code = ICMP_UNREACH_PROTOCOL; | |||||
break; | |||||
} | |||||
/* FALLTHROUGH */ | |||||
default: | |||||
NAT64STAT_INC(stats, dropped); | |||||
return (NAT64MFREE); | |||||
} | |||||
hlen += sizeof(struct icmp6_hdr); | |||||
if (m->m_pkthdr.len < hlen + sizeof(struct ip6_hdr) + ICMP_MINLEN) { | |||||
NAT64STAT_INC(stats, dropped); | |||||
return (NAT64MFREE); | |||||
} | |||||
/* | |||||
* We need at least ICMP_MINLEN bytes of original datagram payload | |||||
* to generate ICMP message. It is nice that ICMP_MINLEN is equal | |||||
* to sizeof(struct ip6_frag). So, if embedded datagram had a fragment | |||||
* header we will not have to do m_pullup() again. | |||||
* | |||||
* What we have here: | |||||
* Outer header: (IPv6iGW, v4mapPRefix+v4exthost) | |||||
* Inner header: (v4mapPRefix+v4host, IPv6iHost) [sport, dport] | |||||
* We need to translate it to: | |||||
* | |||||
* Outer header: (alias_host, v4exthost) | |||||
* Inner header: (v4exthost, alias_host) [sport, alias_port] | |||||
* | |||||
* Assume caller function has checked if v4mapPRefix+v4host | |||||
* matches configured prefix. | |||||
* The only two things we should be provided with are mapping between | |||||
* IPv6iHost <> alias_host and between dport and alias_port. | |||||
*/ | |||||
if (m->m_len < hlen + sizeof(struct ip6_hdr) + ICMP_MINLEN) | |||||
m = m_pullup(m, hlen + sizeof(struct ip6_hdr) + ICMP_MINLEN); | |||||
if (m == NULL) { | |||||
NAT64STAT_INC(stats, nomem); | |||||
return (NAT64RETURN); | |||||
} | |||||
ip6 = mtod(m, struct ip6_hdr *); | |||||
ip6i = mtodo(m, hlen); | |||||
ip6f = NULL; | |||||
proto = ip6i->ip6_nxt; | |||||
plen = ntohs(ip6i->ip6_plen); | |||||
hlen += sizeof(struct ip6_hdr); | |||||
if (proto == IPPROTO_FRAGMENT) { | |||||
if (m->m_pkthdr.len < hlen + sizeof(struct ip6_frag) + | |||||
ICMP_MINLEN) | |||||
goto fail; | |||||
ip6f = mtodo(m, hlen); | |||||
proto = ip6f->ip6f_nxt; | |||||
plen -= sizeof(struct ip6_frag); | |||||
hlen += sizeof(struct ip6_frag); | |||||
if (mtu > 0) | |||||
mtu -= sizeof(struct ip6_frag); | |||||
} | |||||
if (proto != IPPROTO_TCP && proto != IPPROTO_UDP) | |||||
goto fail; | |||||
if (nat64_check_ip6(&ip6i->ip6_src) != 0 || | |||||
nat64_check_ip6(&ip6i->ip6_dst) != 0) | |||||
goto fail; | |||||
/* Check if outer dst is the same as inner src */ | |||||
if (!IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &ip6i->ip6_src)) | |||||
goto fail; | |||||
/* Now we need to make a fake IPv4 packet to generate ICMP message */ | |||||
ip.ip_dst.s_addr = aaddr; | |||||
ip.ip_src.s_addr = nat64_get_ip4(&ip6i->ip6_src); | |||||
/* XXX: Make fake ulp header */ | |||||
ip6i->ip6_hlim += IPV6_HLIMDEC; /* init_ip4hdr will decrement it */ | |||||
nat64_init_ip4hdr(ip6i, ip6f, plen, proto, &ip); | |||||
m_adj(m, hlen - sizeof(struct ip)); | |||||
bcopy(&ip, mtod(m, void *), sizeof(ip)); | |||||
nat64_icmp_reflect(m, type, code, (uint16_t)mtu, stats); | |||||
return (NAT64RETURN); | |||||
fail: | |||||
/* | |||||
* We must call m_freem() because mbuf pointer could be | |||||
* changed with m_pullup(). | |||||
*/ | |||||
m_freem(m); | |||||
NAT64STAT_INC(stats, dropped); | |||||
return (NAT64RETURN); | |||||
} | |||||
int | |||||
nat64_do_handle_ip6(struct mbuf *m, uint32_t aaddr, uint16_t aport, | |||||
nat64_stats_block *stats) | |||||
{ | |||||
struct route ro; | |||||
struct ip ip; | |||||
struct ifnet *ifp; | |||||
struct ip6_frag *frag; | |||||
struct ip6_hbh *hbh; | |||||
struct ip6_hdr *ip6; | |||||
struct icmp6_hdr *icmp6; | |||||
struct sockaddr *dst; | |||||
uint16_t *csum; | |||||
uint32_t mtu; | |||||
int plen, hlen; | |||||
uint8_t proto; | |||||
/* | |||||
* XXX: we expect ipfw_chk() did m_pullup() up to upper level | |||||
* protocol's headers. Also we skip some checks, that ip6_input(), | |||||
* ip6_forward(), ip6_fastfwd() and ipfw_chk() already did. | |||||
*/ | |||||
ip6 = mtod(m, struct ip6_hdr *); | |||||
if (nat64_check_ip6(&ip6->ip6_src) != 0 || | |||||
nat64_check_ip6(&ip6->ip6_dst) != 0) { | |||||
return (NAT64SKIP); | |||||
} | |||||
/* Starting from this point we must not return zero */ | |||||
ip.ip_src.s_addr = aaddr; | |||||
if (nat64_check_ip4(ip.ip_src.s_addr) != 0) { | |||||
DPRINTF("invalid source address: %08x", | |||||
ip.ip_src.s_addr); | |||||
/* XXX: stats? */ | |||||
return (NAT64MFREE); | |||||
} | |||||
ip.ip_dst.s_addr = nat64_get_ip4(&ip6->ip6_dst); | |||||
if (ip.ip_dst.s_addr == 0) { | |||||
/* XXX: stats? */ | |||||
return (NAT64MFREE); | |||||
} | |||||
if (ip6->ip6_hlim <= IPV6_HLIMDEC) { | |||||
nat64_icmp6_reflect(m, ICMP6_TIME_EXCEEDED, | |||||
ICMP6_TIME_EXCEED_TRANSIT, 0, stats); | |||||
return (NAT64RETURN); | |||||
} | |||||
hlen = sizeof(struct ip6_hdr); | |||||
plen = ntohs(ip6->ip6_plen); | |||||
proto = ip6->ip6_nxt; | |||||
/* Skip extension headers */ | |||||
while (proto == IPPROTO_HOPOPTS || proto == IPPROTO_ROUTING || | |||||
proto == IPPROTO_DSTOPTS) { | |||||
hbh = mtodo(m, hlen); | |||||
if (m->m_len < hlen || /* XXX: m_pullup problem */ | |||||
(plen == 0 && proto == IPPROTO_HOPOPTS)) { | |||||
/* XXX: jumbo payload option */ | |||||
NAT64STAT_INC(stats, dropped); | |||||
return (NAT64MFREE); | |||||
} | |||||
proto = hbh->ip6h_nxt; | |||||
hlen += hbh->ip6h_len << 3; | |||||
} | |||||
frag = NULL; | |||||
if (proto == IPPROTO_FRAGMENT) { | |||||
/* XXX: ipfw_chk should m_pullup up to frag header */ | |||||
frag = mtodo(m, hlen); | |||||
proto = frag->ip6f_nxt; | |||||
hlen += sizeof(*frag); | |||||
/* Fragmented ICMPv6 is unsupported */ | |||||
if (proto == IPPROTO_ICMPV6) { | |||||
NAT64STAT_INC(stats, dropped); | |||||
return (NAT64MFREE); | |||||
} | |||||
/* Fragment length must be multiple of 8 octets */ | |||||
if ((frag->ip6f_offlg & IP6F_MORE_FRAG) != 0 && | |||||
((plen + sizeof(struct ip6_hdr) - hlen) & 0x7) != 0) { | |||||
nat64_icmp6_reflect(m, ICMP6_PARAM_PROB, | |||||
ICMP6_PARAMPROB_HEADER, | |||||
offsetof(struct ip6_hdr, ip6_plen), stats); | |||||
return (NAT64RETURN); | |||||
} | |||||
} | |||||
plen -= hlen - sizeof(struct ip6_hdr); | |||||
if (plen < 0 || m->m_pkthdr.len < plen + hlen) { | |||||
DPRINTF("plen %d, pkthdr.len %d, hlen %d", | |||||
plen, m->m_pkthdr.len, hlen); | |||||
NAT64STAT_INC(stats, dropped); | |||||
return (NAT64MFREE); | |||||
} | |||||
icmp6 = NULL; /* Make gcc happy */ | |||||
if (proto == IPPROTO_ICMPV6) { | |||||
icmp6 = mtodo(m, hlen); | |||||
if (icmp6->icmp6_type != ICMP6_ECHO_REQUEST && | |||||
icmp6->icmp6_type != ICMP6_ECHO_REPLY) | |||||
return (nat64_handle_icmp6(m, hlen, aaddr, aport, | |||||
stats)); | |||||
} | |||||
dst = nat64_find_route4(&ro, ip.ip_dst.s_addr, m); | |||||
if (dst == NULL) { | |||||
FREE_ROUTE(&ro); | |||||
NAT64STAT_INC(stats, noroute4); | |||||
nat64_icmp6_reflect(m, ICMP6_DST_UNREACH, | |||||
ICMP6_DST_UNREACH_NOROUTE, 0, stats); | |||||
return (NAT64RETURN); | |||||
} | |||||
ifp = ro.ro_rt->rt_ifp; | |||||
if (ro.ro_rt->rt_mtu != 0) | |||||
mtu = min(ro.ro_rt->rt_mtu, ifp->if_mtu); | |||||
else | |||||
mtu = ifp->if_mtu; | |||||
if (mtu < plen + sizeof(ip)) { | |||||
FREE_ROUTE(&ro); | |||||
nat64_icmp6_reflect(m, ICMP6_PACKET_TOO_BIG, 0, mtu, stats); | |||||
return (NAT64RETURN); | |||||
} | |||||
nat64_init_ip4hdr(ip6, frag, plen, proto, &ip); | |||||
/* Convert checksums. */ | |||||
switch (proto) { | |||||
case IPPROTO_TCP: | |||||
csum = &TCP(mtodo(m, hlen))->th_sum; | |||||
if (aport != 0) { | |||||
struct tcphdr *tcp = TCP(mtodo(m, hlen)); | |||||
*csum = cksum_adjust(*csum, tcp->th_sport, aport); | |||||
tcp->th_sport = aport; | |||||
} | |||||
*csum = cksum_add(*csum, nat64_cksum_convert(ip6, &ip)); | |||||
break; | |||||
case IPPROTO_UDP: | |||||
csum = &UDP(mtodo(m, hlen))->uh_sum; | |||||
if (aport != 0) { | |||||
struct udphdr *udp = UDP(mtodo(m, hlen)); | |||||
*csum = cksum_adjust(*csum, udp->uh_sport, aport); | |||||
udp->uh_sport = aport; | |||||
} | |||||
*csum = cksum_add(*csum, nat64_cksum_convert(ip6, &ip)); | |||||
break; | |||||
case IPPROTO_ICMPV6: | |||||
/* Checksum in ICMPv6 covers pseudo header */ | |||||
csum = &icmp6->icmp6_cksum; | |||||
*csum = cksum_add(*csum, in6_cksum_pseudo(ip6, plen, | |||||
IPPROTO_ICMPV6, 0)); | |||||
/* Convert ICMPv6 types to ICMP */ | |||||
mtu = *(uint16_t *)icmp6; /* save old word for cksum_adjust */ | |||||
if (icmp6->icmp6_type == ICMP6_ECHO_REQUEST) | |||||
icmp6->icmp6_type = ICMP_ECHO; | |||||
else /* ICMP6_ECHO_REPLY */ | |||||
icmp6->icmp6_type = ICMP_ECHOREPLY; | |||||
*csum = cksum_adjust(*csum, (uint16_t)mtu, *(uint16_t *)icmp6); | |||||
if (aport != 0) { | |||||
uint16_t old_id = icmp6->icmp6_id; | |||||
icmp6->icmp6_id = aport; | |||||
*csum = cksum_adjust(*csum, old_id, aport); | |||||
} | |||||
break; | |||||
}; | |||||
m_adj(m, hlen - sizeof(ip)); | |||||
bcopy(&ip, mtod(m, void *), sizeof(ip)); | |||||
if (nat64_output(ifp, m, dst, &ro, stats) == 0) | |||||
NAT64STAT_INC(stats, opcnt64); | |||||
FREE_ROUTE(&ro); | |||||
return (NAT64RETURN); | |||||
} | |||||