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freebsd-skq/sys/netpfil/ipfw/nat64/nat64stl.c
ae 68071c299a Bring in some last changes in NAT64 implementation: 
o Modify ipfw(8) to be able set any prefix6 not just Well-Known,
  and also show configured prefix6;
o relocate some definitions and macros into proper place;
o convert nat64_debug and nat64_allow_private variables to be
  VNET-compatible;
o add struct nat64_config that keeps generic configuration needed
  to NAT64 code;
o add nat64_check_prefix6() function to check validness of specified
  by user IPv6 prefix according to RFC6052;
o use nat64_check_private_ip4() and nat64_embed_ip4() functions
  instead of nat64_get_ip4() and nat64_set_ip4() macros. This allows
  to use any configured IPv6 prefixes that are allowed by RFC6052;
o introduce NAT64_WKPFX flag, that is set when IPv6 prefix is
  Well-Known IPv6 prefix. It is used to reduce overhead to check this;
o modify nat64lsn_cfg and nat64stl_cfg structures to use nat64_config
  structure. And respectivelly modify the rest of code;
o remove now unused ro argument from nat64_output() function;
o remove __FreeBSD_version ifdef, NAT64 was not merged to older versions;
o add commented -DIPFIREWALL_NAT64_DIRECT_OUTPUT flag to module's Makefile
  as example.

Obtained from:	Yandex LLC
MFC after:	1 month
Sponsored by:	Yandex LLC
2018-05-09 11:59:24 +00:00

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/*-
* 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 <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/counter.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/sysctl.h>
#include <net/if.h>
#include <net/if_var.h>
#include <net/if_pflog.h>
#include <net/pfil.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/ip_icmp.h>
#include <netinet/ip_var.h>
#include <netinet/ip_fw.h>
#include <netinet/ip6.h>
#include <netinet/icmp6.h>
#include <netinet6/ip_fw_nat64.h>
#include <netpfil/ipfw/ip_fw_private.h>
#include <netpfil/pf/pf.h>
#include "nat64stl.h"
#define NAT64_LOOKUP(chain, cmd) \
(struct nat64stl_cfg *)SRV_OBJECT((chain), (cmd)->arg1)
static void
nat64stl_log(struct pfloghdr *plog, struct mbuf *m, sa_family_t family,
uint32_t kidx)
{
static uint32_t pktid = 0;
memset(plog, 0, sizeof(*plog));
plog->length = PFLOG_REAL_HDRLEN;
plog->af = family;
plog->action = PF_NAT;
plog->dir = PF_IN;
plog->rulenr = htonl(kidx);
pktid++;
plog->subrulenr = htonl(pktid);
plog->ruleset[0] = '\0';
strlcpy(plog->ifname, "NAT64STL", sizeof(plog->ifname));
ipfw_bpf_mtap2(plog, PFLOG_HDRLEN, m);
}
static int
nat64stl_handle_ip4(struct ip_fw_chain *chain, struct nat64stl_cfg *cfg,
struct mbuf *m, uint32_t tablearg)
{
struct pfloghdr loghdr, *logdata;
struct in6_addr saddr, daddr;
struct ip *ip;
ip = mtod(m, struct ip*);
if (nat64_check_ip4(ip->ip_src.s_addr) != 0 ||
nat64_check_ip4(ip->ip_dst.s_addr) != 0 ||
nat64_check_private_ip4(&cfg->base, ip->ip_src.s_addr) != 0 ||
nat64_check_private_ip4(&cfg->base, ip->ip_dst.s_addr) != 0)
return (NAT64SKIP);
daddr = TARG_VAL(chain, tablearg, nh6);
if (nat64_check_ip6(&daddr) != 0)
return (NAT64MFREE);
nat64_embed_ip4(&cfg->base, ip->ip_src.s_addr, &saddr);
if (cfg->base.flags & NAT64_LOG) {
logdata = &loghdr;
nat64stl_log(logdata, m, AF_INET, cfg->no.kidx);
} else
logdata = NULL;
return (nat64_do_handle_ip4(m, &saddr, &daddr, 0, &cfg->base,
logdata));
}
static int
nat64stl_handle_ip6(struct ip_fw_chain *chain, struct nat64stl_cfg *cfg,
struct mbuf *m, uint32_t tablearg)
{
struct pfloghdr loghdr, *logdata;
struct ip6_hdr *ip6;
uint32_t aaddr;
aaddr = htonl(TARG_VAL(chain, tablearg, nh4));
/*
* NOTE: 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 *);
/* Check ip6_dst matches configured prefix */
if (bcmp(&ip6->ip6_dst, &cfg->base.prefix6, cfg->base.plen6 / 8) != 0)
return (NAT64SKIP);
if (cfg->base.flags & NAT64_LOG) {
logdata = &loghdr;
nat64stl_log(logdata, m, AF_INET6, cfg->no.kidx);
} else
logdata = NULL;
return (nat64_do_handle_ip6(m, aaddr, 0, &cfg->base, logdata));
}
static int
nat64stl_handle_icmp6(struct ip_fw_chain *chain, struct nat64stl_cfg *cfg,
struct mbuf *m)
{
struct pfloghdr loghdr, *logdata;
struct nat64_counters *stats;
struct ip6_hdr *ip6i;
struct icmp6_hdr *icmp6;
uint32_t tablearg;
int hlen, proto;
hlen = 0;
stats = &cfg->base.stats;
proto = nat64_getlasthdr(m, &hlen);
if (proto != IPPROTO_ICMPV6) {
NAT64STAT_INC(stats, dropped);
return (NAT64MFREE);
}
icmp6 = mtodo(m, hlen);
switch (icmp6->icmp6_type) {
case ICMP6_DST_UNREACH:
case ICMP6_PACKET_TOO_BIG:
case ICMP6_TIME_EXCEED_TRANSIT:
case ICMP6_PARAM_PROB:
break;
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);
}
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);
}
/*
* Use destination address from inner IPv6 header to determine
* IPv4 mapped address.
*/
ip6i = mtodo(m, hlen);
if (ipfw_lookup_table(chain, cfg->map64,
sizeof(struct in6_addr), &ip6i->ip6_dst, &tablearg) == 0) {
m_freem(m);
return (NAT64RETURN);
}
if (cfg->base.flags & NAT64_LOG) {
logdata = &loghdr;
nat64stl_log(logdata, m, AF_INET6, cfg->no.kidx);
} else
logdata = NULL;
return (nat64_handle_icmp6(m, 0,
htonl(TARG_VAL(chain, tablearg, nh4)), 0, &cfg->base, logdata));
}
int
ipfw_nat64stl(struct ip_fw_chain *chain, struct ip_fw_args *args,
ipfw_insn *cmd, int *done)
{
ipfw_insn *icmd;
struct nat64stl_cfg *cfg;
in_addr_t dst4;
uint32_t tablearg;
int ret;
IPFW_RLOCK_ASSERT(chain);
*done = 0; /* try next rule if not matched */
icmd = cmd + 1;
if (cmd->opcode != O_EXTERNAL_ACTION ||
cmd->arg1 != V_nat64stl_eid ||
icmd->opcode != O_EXTERNAL_INSTANCE ||
(cfg = NAT64_LOOKUP(chain, icmd)) == NULL)
return (0);
switch (args->f_id.addr_type) {
case 4:
dst4 = htonl(args->f_id.dst_ip);
ret = ipfw_lookup_table(chain, cfg->map46, sizeof(in_addr_t),
&dst4, &tablearg);
break;
case 6:
ret = ipfw_lookup_table(chain, cfg->map64,
sizeof(struct in6_addr), &args->f_id.src_ip6, &tablearg);
break;
default:
return (0);
}
if (ret == 0) {
/*
* In case when packet is ICMPv6 message from an intermediate
* router, the source address of message will not match the
* addresses from our map64 table.
*/
if (args->f_id.proto != IPPROTO_ICMPV6)
return (0);
ret = nat64stl_handle_icmp6(chain, cfg, args->m);
} else {
if (args->f_id.addr_type == 4)
ret = nat64stl_handle_ip4(chain, cfg, args->m,
tablearg);
else
ret = nat64stl_handle_ip6(chain, cfg, args->m,
tablearg);
}
if (ret == NAT64SKIP)
return (0);
*done = 1; /* terminate the search */
if (ret == NAT64MFREE)
m_freem(args->m);
args->m = NULL;
return (IP_FW_DENY);
}
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