1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2015-2019 Yandex LLC
5 * Copyright (c) 2015-2019 Andrey V. Elsukov <ae@FreeBSD.org>
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 *
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 #include <sys/param.h>
30 #include <sys/systm.h>
31 #include <sys/counter.h>
32 #include <sys/kernel.h>
33 #include <sys/lock.h>
34 #include <sys/mbuf.h>
35 #include <sys/module.h>
36 #include <sys/rmlock.h>
37 #include <sys/rwlock.h>
38 #include <sys/socket.h>
39 #include <sys/sysctl.h>
40
41 #include <net/if.h>
42 #include <net/if_var.h>
43 #include <net/if_pflog.h>
44 #include <net/pfil.h>
45
46 #include <netinet/in.h>
47 #include <netinet/ip.h>
48 #include <netinet/ip_icmp.h>
49 #include <netinet/ip_var.h>
50 #include <netinet/ip_fw.h>
51 #include <netinet/ip6.h>
52 #include <netinet/icmp6.h>
53 #include <netinet6/ip_fw_nat64.h>
54
55 #include <netpfil/ipfw/ip_fw_private.h>
56 #include <netpfil/pf/pf.h>
57
58 #include "nat64stl.h"
59
60 #define NAT64_LOOKUP(chain, cmd) \
61 (struct nat64stl_cfg *)SRV_OBJECT((chain), (cmd)->arg1)
62
63 static void
nat64stl_log(struct pfloghdr * plog,struct mbuf * m,sa_family_t family,uint32_t kidx)64 nat64stl_log(struct pfloghdr *plog, struct mbuf *m, sa_family_t family,
65 uint32_t kidx)
66 {
67 static uint32_t pktid = 0;
68
69 memset(plog, 0, sizeof(*plog));
70 plog->length = PFLOG_HDRLEN;
71 plog->af = family;
72 plog->action = PF_NAT;
73 plog->dir = PF_IN;
74 plog->rulenr = htonl(kidx);
75 pktid++;
76 plog->subrulenr = htonl(pktid);
77 plog->ruleset[0] = '\0';
78 strlcpy(plog->ifname, "NAT64STL", sizeof(plog->ifname));
79 ipfw_bpf_mtap2(plog, PFLOG_HDRLEN, m);
80 }
81
82 static int
nat64stl_handle_ip4(struct ip_fw_chain * chain,struct nat64stl_cfg * cfg,struct mbuf * m,uint32_t tablearg)83 nat64stl_handle_ip4(struct ip_fw_chain *chain, struct nat64stl_cfg *cfg,
84 struct mbuf *m, uint32_t tablearg)
85 {
86 struct pfloghdr loghdr, *logdata;
87 struct in6_addr saddr, daddr;
88 struct ip *ip;
89
90 ip = mtod(m, struct ip*);
91 if (nat64_check_ip4(ip->ip_src.s_addr) != 0 ||
92 nat64_check_ip4(ip->ip_dst.s_addr) != 0 ||
93 nat64_check_private_ip4(&cfg->base, ip->ip_src.s_addr) != 0 ||
94 nat64_check_private_ip4(&cfg->base, ip->ip_dst.s_addr) != 0)
95 return (NAT64SKIP);
96
97 daddr = TARG_VAL(chain, tablearg, nh6);
98 if (nat64_check_ip6(&daddr) != 0)
99 return (NAT64MFREE);
100
101 saddr = cfg->base.plat_prefix;
102 nat64_embed_ip4(&saddr, cfg->base.plat_plen, ip->ip_src.s_addr);
103 if (cfg->base.flags & NAT64_LOG) {
104 logdata = &loghdr;
105 nat64stl_log(logdata, m, AF_INET, cfg->no.kidx);
106 } else
107 logdata = NULL;
108 return (nat64_do_handle_ip4(m, &saddr, &daddr, 0, &cfg->base,
109 logdata));
110 }
111
112 static int
nat64stl_handle_ip6(struct ip_fw_chain * chain,struct nat64stl_cfg * cfg,struct mbuf * m,uint32_t tablearg)113 nat64stl_handle_ip6(struct ip_fw_chain *chain, struct nat64stl_cfg *cfg,
114 struct mbuf *m, uint32_t tablearg)
115 {
116 struct pfloghdr loghdr, *logdata;
117 struct ip6_hdr *ip6;
118 uint32_t aaddr;
119
120 aaddr = htonl(TARG_VAL(chain, tablearg, nh4));
121 if (nat64_check_private_ip4(&cfg->base, aaddr) != 0) {
122 NAT64STAT_INC(&cfg->base.stats, dropped);
123 return (NAT64MFREE);
124 }
125 /*
126 * NOTE: we expect ipfw_chk() did m_pullup() up to upper level
127 * protocol's headers. Also we skip some checks, that ip6_input(),
128 * ip6_forward(), ip6_fastfwd() and ipfw_chk() already did.
129 */
130 ip6 = mtod(m, struct ip6_hdr *);
131 /* Check ip6_dst matches configured prefix */
132 if (memcmp(&ip6->ip6_dst, &cfg->base.plat_prefix,
133 cfg->base.plat_plen / 8) != 0)
134 return (NAT64SKIP);
135
136 if (cfg->base.flags & NAT64_LOG) {
137 logdata = &loghdr;
138 nat64stl_log(logdata, m, AF_INET6, cfg->no.kidx);
139 } else
140 logdata = NULL;
141 return (nat64_do_handle_ip6(m, aaddr, 0, &cfg->base, logdata));
142 }
143
144 static int
nat64stl_handle_icmp6(struct ip_fw_chain * chain,struct nat64stl_cfg * cfg,struct mbuf * m)145 nat64stl_handle_icmp6(struct ip_fw_chain *chain, struct nat64stl_cfg *cfg,
146 struct mbuf *m)
147 {
148 struct pfloghdr loghdr, *logdata;
149 struct nat64_counters *stats;
150 struct ip6_hdr *ip6i;
151 struct icmp6_hdr *icmp6;
152 uint32_t tablearg;
153 int hlen, proto;
154
155 hlen = 0;
156 stats = &cfg->base.stats;
157 proto = nat64_getlasthdr(m, &hlen);
158 if (proto != IPPROTO_ICMPV6) {
159 NAT64STAT_INC(stats, dropped);
160 return (NAT64MFREE);
161 }
162 icmp6 = mtodo(m, hlen);
163 switch (icmp6->icmp6_type) {
164 case ICMP6_DST_UNREACH:
165 case ICMP6_PACKET_TOO_BIG:
166 case ICMP6_TIME_EXCEED_TRANSIT:
167 case ICMP6_PARAM_PROB:
168 break;
169 default:
170 NAT64STAT_INC(stats, dropped);
171 return (NAT64MFREE);
172 }
173 hlen += sizeof(struct icmp6_hdr);
174 if (m->m_pkthdr.len < hlen + sizeof(struct ip6_hdr) + ICMP_MINLEN) {
175 NAT64STAT_INC(stats, dropped);
176 return (NAT64MFREE);
177 }
178 if (m->m_len < hlen + sizeof(struct ip6_hdr) + ICMP_MINLEN)
179 m = m_pullup(m, hlen + sizeof(struct ip6_hdr) + ICMP_MINLEN);
180 if (m == NULL) {
181 NAT64STAT_INC(stats, nomem);
182 return (NAT64RETURN);
183 }
184 /*
185 * Use destination address from inner IPv6 header to determine
186 * IPv4 mapped address.
187 */
188 ip6i = mtodo(m, hlen);
189 if (ipfw_lookup_table(chain, cfg->map64,
190 sizeof(struct in6_addr), &ip6i->ip6_dst, &tablearg) == 0) {
191 m_freem(m);
192 return (NAT64RETURN);
193 }
194 if (cfg->base.flags & NAT64_LOG) {
195 logdata = &loghdr;
196 nat64stl_log(logdata, m, AF_INET6, cfg->no.kidx);
197 } else
198 logdata = NULL;
199 return (nat64_handle_icmp6(m, 0,
200 htonl(TARG_VAL(chain, tablearg, nh4)), 0, &cfg->base, logdata));
201 }
202
203 int
ipfw_nat64stl(struct ip_fw_chain * chain,struct ip_fw_args * args,ipfw_insn * cmd,int * done)204 ipfw_nat64stl(struct ip_fw_chain *chain, struct ip_fw_args *args,
205 ipfw_insn *cmd, int *done)
206 {
207 ipfw_insn *icmd;
208 struct nat64stl_cfg *cfg;
209 in_addr_t dst4;
210 uint32_t tablearg;
211 int ret;
212
213 IPFW_RLOCK_ASSERT(chain);
214
215 *done = 0; /* try next rule if not matched */
216 icmd = cmd + 1;
217 if (cmd->opcode != O_EXTERNAL_ACTION ||
218 cmd->arg1 != V_nat64stl_eid ||
219 icmd->opcode != O_EXTERNAL_INSTANCE ||
220 (cfg = NAT64_LOOKUP(chain, icmd)) == NULL)
221 return (0);
222
223 switch (args->f_id.addr_type) {
224 case 4:
225 dst4 = htonl(args->f_id.dst_ip);
226 ret = ipfw_lookup_table(chain, cfg->map46, sizeof(in_addr_t),
227 &dst4, &tablearg);
228 break;
229 case 6:
230 ret = ipfw_lookup_table(chain, cfg->map64,
231 sizeof(struct in6_addr), &args->f_id.src_ip6, &tablearg);
232 break;
233 default:
234 return (0);
235 }
236 if (ret == 0) {
237 /*
238 * In case when packet is ICMPv6 message from an intermediate
239 * router, the source address of message will not match the
240 * addresses from our map64 table.
241 */
242 if (args->f_id.proto != IPPROTO_ICMPV6)
243 return (0);
244
245 ret = nat64stl_handle_icmp6(chain, cfg, args->m);
246 } else {
247 if (args->f_id.addr_type == 4)
248 ret = nat64stl_handle_ip4(chain, cfg, args->m,
249 tablearg);
250 else
251 ret = nat64stl_handle_ip6(chain, cfg, args->m,
252 tablearg);
253 }
254 if (ret == NAT64SKIP)
255 return (0);
256
257 *done = 1; /* terminate the search */
258 if (ret == NAT64MFREE)
259 m_freem(args->m);
260 args->m = NULL;
261 return (IP_FW_NAT64);
262 }
263