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Commit | Line | Data |
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cf308a1f HS |
1 | /* |
2 | * xt_HMARK - Netfilter module to set mark by means of hashing | |
3 | * | |
4 | * (C) 2012 by Hans Schillstrom <hans.schillstrom@ericsson.com> | |
5 | * (C) 2012 by Pablo Neira Ayuso <pablo@netfilter.org> | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify it | |
8 | * under the terms of the GNU General Public License version 2 as published by | |
9 | * the Free Software Foundation. | |
10 | */ | |
11 | ||
12 | #include <linux/module.h> | |
13 | #include <linux/skbuff.h> | |
14 | #include <linux/icmp.h> | |
15 | ||
16 | #include <linux/netfilter/x_tables.h> | |
17 | #include <linux/netfilter/xt_HMARK.h> | |
18 | ||
19 | #include <net/ip.h> | |
20 | #if IS_ENABLED(CONFIG_NF_CONNTRACK) | |
21 | #include <net/netfilter/nf_conntrack.h> | |
22 | #endif | |
23 | #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) | |
24 | #include <net/ipv6.h> | |
25 | #include <linux/netfilter_ipv6/ip6_tables.h> | |
26 | #endif | |
27 | ||
28 | MODULE_LICENSE("GPL"); | |
29 | MODULE_AUTHOR("Hans Schillstrom <hans.schillstrom@ericsson.com>"); | |
30 | MODULE_DESCRIPTION("Xtables: packet marking using hash calculation"); | |
31 | MODULE_ALIAS("ipt_HMARK"); | |
32 | MODULE_ALIAS("ip6t_HMARK"); | |
33 | ||
34 | struct hmark_tuple { | |
d1992b16 HS |
35 | __be32 src; |
36 | __be32 dst; | |
cf308a1f | 37 | union hmark_ports uports; |
d1992b16 | 38 | u8 proto; |
cf308a1f HS |
39 | }; |
40 | ||
d1992b16 | 41 | static inline __be32 hmark_addr6_mask(const __be32 *addr32, const __be32 *mask) |
cf308a1f HS |
42 | { |
43 | return (addr32[0] & mask[0]) ^ | |
44 | (addr32[1] & mask[1]) ^ | |
45 | (addr32[2] & mask[2]) ^ | |
46 | (addr32[3] & mask[3]); | |
47 | } | |
48 | ||
d1992b16 HS |
49 | static inline __be32 |
50 | hmark_addr_mask(int l3num, const __be32 *addr32, const __be32 *mask) | |
cf308a1f HS |
51 | { |
52 | switch (l3num) { | |
53 | case AF_INET: | |
54 | return *addr32 & *mask; | |
55 | case AF_INET6: | |
56 | return hmark_addr6_mask(addr32, mask); | |
57 | } | |
58 | return 0; | |
59 | } | |
60 | ||
d1992b16 HS |
61 | static inline void hmark_swap_ports(union hmark_ports *uports, |
62 | const struct xt_hmark_info *info) | |
63 | { | |
64 | union hmark_ports hp; | |
65 | u16 src, dst; | |
66 | ||
67 | hp.b32 = (uports->b32 & info->port_mask.b32) | info->port_set.b32; | |
68 | src = ntohs(hp.b16.src); | |
69 | dst = ntohs(hp.b16.dst); | |
70 | ||
71 | if (dst > src) | |
72 | uports->v32 = (dst << 16) | src; | |
73 | else | |
74 | uports->v32 = (src << 16) | dst; | |
75 | } | |
76 | ||
cf308a1f HS |
77 | static int |
78 | hmark_ct_set_htuple(const struct sk_buff *skb, struct hmark_tuple *t, | |
79 | const struct xt_hmark_info *info) | |
80 | { | |
81 | #if IS_ENABLED(CONFIG_NF_CONNTRACK) | |
82 | enum ip_conntrack_info ctinfo; | |
83 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
84 | struct nf_conntrack_tuple *otuple; | |
85 | struct nf_conntrack_tuple *rtuple; | |
86 | ||
87 | if (ct == NULL || nf_ct_is_untracked(ct)) | |
88 | return -1; | |
89 | ||
90 | otuple = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple; | |
91 | rtuple = &ct->tuplehash[IP_CT_DIR_REPLY].tuple; | |
92 | ||
d1992b16 HS |
93 | t->src = hmark_addr_mask(otuple->src.l3num, otuple->src.u3.ip6, |
94 | info->src_mask.ip6); | |
95 | t->dst = hmark_addr_mask(otuple->src.l3num, rtuple->src.u3.ip6, | |
96 | info->dst_mask.ip6); | |
cf308a1f HS |
97 | |
98 | if (info->flags & XT_HMARK_FLAG(XT_HMARK_METHOD_L3)) | |
99 | return 0; | |
100 | ||
101 | t->proto = nf_ct_protonum(ct); | |
102 | if (t->proto != IPPROTO_ICMP) { | |
d1992b16 HS |
103 | t->uports.b16.src = otuple->src.u.all; |
104 | t->uports.b16.dst = rtuple->src.u.all; | |
105 | hmark_swap_ports(&t->uports, info); | |
cf308a1f HS |
106 | } |
107 | ||
108 | return 0; | |
109 | #else | |
110 | return -1; | |
111 | #endif | |
112 | } | |
113 | ||
d1992b16 HS |
114 | /* This hash function is endian independent, to ensure consistent hashing if |
115 | * the cluster is composed of big and little endian systems. */ | |
cf308a1f HS |
116 | static inline u32 |
117 | hmark_hash(struct hmark_tuple *t, const struct xt_hmark_info *info) | |
118 | { | |
119 | u32 hash; | |
d1992b16 HS |
120 | u32 src = ntohl(t->src); |
121 | u32 dst = ntohl(t->dst); | |
cf308a1f | 122 | |
d1992b16 HS |
123 | if (dst < src) |
124 | swap(src, dst); | |
cf308a1f | 125 | |
d1992b16 | 126 | hash = jhash_3words(src, dst, t->uports.v32, info->hashrnd); |
cf308a1f HS |
127 | hash = hash ^ (t->proto & info->proto_mask); |
128 | ||
8fc54f68 | 129 | return reciprocal_scale(hash, info->hmodulus) + info->hoffset; |
cf308a1f HS |
130 | } |
131 | ||
132 | static void | |
133 | hmark_set_tuple_ports(const struct sk_buff *skb, unsigned int nhoff, | |
134 | struct hmark_tuple *t, const struct xt_hmark_info *info) | |
135 | { | |
136 | int protoff; | |
137 | ||
138 | protoff = proto_ports_offset(t->proto); | |
139 | if (protoff < 0) | |
140 | return; | |
141 | ||
142 | nhoff += protoff; | |
143 | if (skb_copy_bits(skb, nhoff, &t->uports, sizeof(t->uports)) < 0) | |
144 | return; | |
145 | ||
d1992b16 | 146 | hmark_swap_ports(&t->uports, info); |
cf308a1f HS |
147 | } |
148 | ||
149 | #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) | |
150 | static int get_inner6_hdr(const struct sk_buff *skb, int *offset) | |
151 | { | |
152 | struct icmp6hdr *icmp6h, _ih6; | |
153 | ||
154 | icmp6h = skb_header_pointer(skb, *offset, sizeof(_ih6), &_ih6); | |
155 | if (icmp6h == NULL) | |
156 | return 0; | |
157 | ||
158 | if (icmp6h->icmp6_type && icmp6h->icmp6_type < 128) { | |
159 | *offset += sizeof(struct icmp6hdr); | |
160 | return 1; | |
161 | } | |
162 | return 0; | |
163 | } | |
164 | ||
165 | static int | |
166 | hmark_pkt_set_htuple_ipv6(const struct sk_buff *skb, struct hmark_tuple *t, | |
167 | const struct xt_hmark_info *info) | |
168 | { | |
169 | struct ipv6hdr *ip6, _ip6; | |
f8f62675 | 170 | int flag = IP6_FH_F_AUTH; |
cf308a1f HS |
171 | unsigned int nhoff = 0; |
172 | u16 fragoff = 0; | |
173 | int nexthdr; | |
174 | ||
175 | ip6 = (struct ipv6hdr *) (skb->data + skb_network_offset(skb)); | |
176 | nexthdr = ipv6_find_hdr(skb, &nhoff, -1, &fragoff, &flag); | |
177 | if (nexthdr < 0) | |
178 | return 0; | |
179 | /* No need to check for icmp errors on fragments */ | |
f8f62675 | 180 | if ((flag & IP6_FH_F_FRAG) || (nexthdr != IPPROTO_ICMPV6)) |
cf308a1f HS |
181 | goto noicmp; |
182 | /* Use inner header in case of ICMP errors */ | |
183 | if (get_inner6_hdr(skb, &nhoff)) { | |
184 | ip6 = skb_header_pointer(skb, nhoff, sizeof(_ip6), &_ip6); | |
185 | if (ip6 == NULL) | |
186 | return -1; | |
187 | /* If AH present, use SPI like in ESP. */ | |
f8f62675 | 188 | flag = IP6_FH_F_AUTH; |
cf308a1f HS |
189 | nexthdr = ipv6_find_hdr(skb, &nhoff, -1, &fragoff, &flag); |
190 | if (nexthdr < 0) | |
191 | return -1; | |
192 | } | |
193 | noicmp: | |
d1992b16 HS |
194 | t->src = hmark_addr6_mask(ip6->saddr.s6_addr32, info->src_mask.ip6); |
195 | t->dst = hmark_addr6_mask(ip6->daddr.s6_addr32, info->dst_mask.ip6); | |
cf308a1f HS |
196 | |
197 | if (info->flags & XT_HMARK_FLAG(XT_HMARK_METHOD_L3)) | |
198 | return 0; | |
199 | ||
200 | t->proto = nexthdr; | |
201 | if (t->proto == IPPROTO_ICMPV6) | |
202 | return 0; | |
203 | ||
f8f62675 | 204 | if (flag & IP6_FH_F_FRAG) |
cf308a1f HS |
205 | return 0; |
206 | ||
207 | hmark_set_tuple_ports(skb, nhoff, t, info); | |
208 | return 0; | |
209 | } | |
210 | ||
211 | static unsigned int | |
212 | hmark_tg_v6(struct sk_buff *skb, const struct xt_action_param *par) | |
213 | { | |
214 | const struct xt_hmark_info *info = par->targinfo; | |
215 | struct hmark_tuple t; | |
216 | ||
217 | memset(&t, 0, sizeof(struct hmark_tuple)); | |
218 | ||
219 | if (info->flags & XT_HMARK_FLAG(XT_HMARK_CT)) { | |
220 | if (hmark_ct_set_htuple(skb, &t, info) < 0) | |
221 | return XT_CONTINUE; | |
222 | } else { | |
223 | if (hmark_pkt_set_htuple_ipv6(skb, &t, info) < 0) | |
224 | return XT_CONTINUE; | |
225 | } | |
226 | ||
227 | skb->mark = hmark_hash(&t, info); | |
228 | return XT_CONTINUE; | |
229 | } | |
230 | #endif | |
231 | ||
232 | static int get_inner_hdr(const struct sk_buff *skb, int iphsz, int *nhoff) | |
233 | { | |
234 | const struct icmphdr *icmph; | |
235 | struct icmphdr _ih; | |
236 | ||
237 | /* Not enough header? */ | |
238 | icmph = skb_header_pointer(skb, *nhoff + iphsz, sizeof(_ih), &_ih); | |
58618115 | 239 | if (icmph == NULL || icmph->type > NR_ICMP_TYPES) |
cf308a1f HS |
240 | return 0; |
241 | ||
242 | /* Error message? */ | |
243 | if (icmph->type != ICMP_DEST_UNREACH && | |
244 | icmph->type != ICMP_SOURCE_QUENCH && | |
245 | icmph->type != ICMP_TIME_EXCEEDED && | |
246 | icmph->type != ICMP_PARAMETERPROB && | |
247 | icmph->type != ICMP_REDIRECT) | |
248 | return 0; | |
249 | ||
250 | *nhoff += iphsz + sizeof(_ih); | |
251 | return 1; | |
252 | } | |
253 | ||
254 | static int | |
255 | hmark_pkt_set_htuple_ipv4(const struct sk_buff *skb, struct hmark_tuple *t, | |
256 | const struct xt_hmark_info *info) | |
257 | { | |
258 | struct iphdr *ip, _ip; | |
259 | int nhoff = skb_network_offset(skb); | |
260 | ||
261 | ip = (struct iphdr *) (skb->data + nhoff); | |
262 | if (ip->protocol == IPPROTO_ICMP) { | |
263 | /* Use inner header in case of ICMP errors */ | |
264 | if (get_inner_hdr(skb, ip->ihl * 4, &nhoff)) { | |
265 | ip = skb_header_pointer(skb, nhoff, sizeof(_ip), &_ip); | |
266 | if (ip == NULL) | |
267 | return -1; | |
268 | } | |
269 | } | |
270 | ||
d1992b16 HS |
271 | t->src = ip->saddr & info->src_mask.ip; |
272 | t->dst = ip->daddr & info->dst_mask.ip; | |
cf308a1f HS |
273 | |
274 | if (info->flags & XT_HMARK_FLAG(XT_HMARK_METHOD_L3)) | |
275 | return 0; | |
276 | ||
277 | t->proto = ip->protocol; | |
278 | ||
279 | /* ICMP has no ports, skip */ | |
280 | if (t->proto == IPPROTO_ICMP) | |
281 | return 0; | |
282 | ||
283 | /* follow-up fragments don't contain ports, skip all fragments */ | |
284 | if (ip->frag_off & htons(IP_MF | IP_OFFSET)) | |
285 | return 0; | |
286 | ||
287 | hmark_set_tuple_ports(skb, (ip->ihl * 4) + nhoff, t, info); | |
288 | ||
289 | return 0; | |
290 | } | |
291 | ||
292 | static unsigned int | |
293 | hmark_tg_v4(struct sk_buff *skb, const struct xt_action_param *par) | |
294 | { | |
295 | const struct xt_hmark_info *info = par->targinfo; | |
296 | struct hmark_tuple t; | |
297 | ||
298 | memset(&t, 0, sizeof(struct hmark_tuple)); | |
299 | ||
300 | if (info->flags & XT_HMARK_FLAG(XT_HMARK_CT)) { | |
301 | if (hmark_ct_set_htuple(skb, &t, info) < 0) | |
302 | return XT_CONTINUE; | |
303 | } else { | |
304 | if (hmark_pkt_set_htuple_ipv4(skb, &t, info) < 0) | |
305 | return XT_CONTINUE; | |
306 | } | |
307 | ||
308 | skb->mark = hmark_hash(&t, info); | |
309 | return XT_CONTINUE; | |
310 | } | |
311 | ||
312 | static int hmark_tg_check(const struct xt_tgchk_param *par) | |
313 | { | |
314 | const struct xt_hmark_info *info = par->targinfo; | |
315 | ||
316 | if (!info->hmodulus) { | |
317 | pr_info("xt_HMARK: hash modulus can't be zero\n"); | |
318 | return -EINVAL; | |
319 | } | |
320 | if (info->proto_mask && | |
321 | (info->flags & XT_HMARK_FLAG(XT_HMARK_METHOD_L3))) { | |
322 | pr_info("xt_HMARK: proto mask must be zero with L3 mode\n"); | |
323 | return -EINVAL; | |
324 | } | |
325 | if (info->flags & XT_HMARK_FLAG(XT_HMARK_SPI_MASK) && | |
326 | (info->flags & (XT_HMARK_FLAG(XT_HMARK_SPORT_MASK) | | |
327 | XT_HMARK_FLAG(XT_HMARK_DPORT_MASK)))) { | |
328 | pr_info("xt_HMARK: spi-mask and port-mask can't be combined\n"); | |
329 | return -EINVAL; | |
330 | } | |
331 | if (info->flags & XT_HMARK_FLAG(XT_HMARK_SPI) && | |
332 | (info->flags & (XT_HMARK_FLAG(XT_HMARK_SPORT) | | |
333 | XT_HMARK_FLAG(XT_HMARK_DPORT)))) { | |
334 | pr_info("xt_HMARK: spi-set and port-set can't be combined\n"); | |
335 | return -EINVAL; | |
336 | } | |
337 | return 0; | |
338 | } | |
339 | ||
340 | static struct xt_target hmark_tg_reg[] __read_mostly = { | |
341 | { | |
342 | .name = "HMARK", | |
343 | .family = NFPROTO_IPV4, | |
344 | .target = hmark_tg_v4, | |
345 | .targetsize = sizeof(struct xt_hmark_info), | |
346 | .checkentry = hmark_tg_check, | |
347 | .me = THIS_MODULE, | |
348 | }, | |
349 | #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) | |
350 | { | |
351 | .name = "HMARK", | |
352 | .family = NFPROTO_IPV6, | |
353 | .target = hmark_tg_v6, | |
354 | .targetsize = sizeof(struct xt_hmark_info), | |
355 | .checkentry = hmark_tg_check, | |
356 | .me = THIS_MODULE, | |
357 | }, | |
358 | #endif | |
359 | }; | |
360 | ||
361 | static int __init hmark_tg_init(void) | |
362 | { | |
363 | return xt_register_targets(hmark_tg_reg, ARRAY_SIZE(hmark_tg_reg)); | |
364 | } | |
365 | ||
366 | static void __exit hmark_tg_exit(void) | |
367 | { | |
368 | xt_unregister_targets(hmark_tg_reg, ARRAY_SIZE(hmark_tg_reg)); | |
369 | } | |
370 | ||
371 | module_init(hmark_tg_init); | |
372 | module_exit(hmark_tg_exit); |