Commit | Line | Data |
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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
cf308a1f HS |
2 | /* |
3 | * xt_HMARK - Netfilter module to set mark by means of hashing | |
4 | * | |
5 | * (C) 2012 by Hans Schillstrom <hans.schillstrom@ericsson.com> | |
6 | * (C) 2012 by Pablo Neira Ayuso <pablo@netfilter.org> | |
cf308a1f HS |
7 | */ |
8 | ||
c08e5e1e FW |
9 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
10 | ||
cf308a1f HS |
11 | #include <linux/module.h> |
12 | #include <linux/skbuff.h> | |
13 | #include <linux/icmp.h> | |
14 | ||
15 | #include <linux/netfilter/x_tables.h> | |
16 | #include <linux/netfilter/xt_HMARK.h> | |
17 | ||
18 | #include <net/ip.h> | |
19 | #if IS_ENABLED(CONFIG_NF_CONNTRACK) | |
20 | #include <net/netfilter/nf_conntrack.h> | |
21 | #endif | |
22 | #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) | |
23 | #include <net/ipv6.h> | |
24 | #include <linux/netfilter_ipv6/ip6_tables.h> | |
25 | #endif | |
26 | ||
27 | MODULE_LICENSE("GPL"); | |
28 | MODULE_AUTHOR("Hans Schillstrom <hans.schillstrom@ericsson.com>"); | |
29 | MODULE_DESCRIPTION("Xtables: packet marking using hash calculation"); | |
30 | MODULE_ALIAS("ipt_HMARK"); | |
31 | MODULE_ALIAS("ip6t_HMARK"); | |
32 | ||
33 | struct hmark_tuple { | |
d1992b16 HS |
34 | __be32 src; |
35 | __be32 dst; | |
cf308a1f | 36 | union hmark_ports uports; |
d1992b16 | 37 | u8 proto; |
cf308a1f HS |
38 | }; |
39 | ||
d1992b16 | 40 | static inline __be32 hmark_addr6_mask(const __be32 *addr32, const __be32 *mask) |
cf308a1f HS |
41 | { |
42 | return (addr32[0] & mask[0]) ^ | |
43 | (addr32[1] & mask[1]) ^ | |
44 | (addr32[2] & mask[2]) ^ | |
45 | (addr32[3] & mask[3]); | |
46 | } | |
47 | ||
d1992b16 HS |
48 | static inline __be32 |
49 | hmark_addr_mask(int l3num, const __be32 *addr32, const __be32 *mask) | |
cf308a1f HS |
50 | { |
51 | switch (l3num) { | |
52 | case AF_INET: | |
53 | return *addr32 & *mask; | |
54 | case AF_INET6: | |
55 | return hmark_addr6_mask(addr32, mask); | |
56 | } | |
57 | return 0; | |
58 | } | |
59 | ||
d1992b16 HS |
60 | static inline void hmark_swap_ports(union hmark_ports *uports, |
61 | const struct xt_hmark_info *info) | |
62 | { | |
63 | union hmark_ports hp; | |
64 | u16 src, dst; | |
65 | ||
66 | hp.b32 = (uports->b32 & info->port_mask.b32) | info->port_set.b32; | |
67 | src = ntohs(hp.b16.src); | |
68 | dst = ntohs(hp.b16.dst); | |
69 | ||
70 | if (dst > src) | |
71 | uports->v32 = (dst << 16) | src; | |
72 | else | |
73 | uports->v32 = (src << 16) | dst; | |
74 | } | |
75 | ||
cf308a1f HS |
76 | static int |
77 | hmark_ct_set_htuple(const struct sk_buff *skb, struct hmark_tuple *t, | |
78 | const struct xt_hmark_info *info) | |
79 | { | |
80 | #if IS_ENABLED(CONFIG_NF_CONNTRACK) | |
81 | enum ip_conntrack_info ctinfo; | |
82 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); | |
83 | struct nf_conntrack_tuple *otuple; | |
84 | struct nf_conntrack_tuple *rtuple; | |
85 | ||
ab8bc7ed | 86 | if (ct == NULL) |
cf308a1f HS |
87 | return -1; |
88 | ||
89 | otuple = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple; | |
90 | rtuple = &ct->tuplehash[IP_CT_DIR_REPLY].tuple; | |
91 | ||
d1992b16 HS |
92 | t->src = hmark_addr_mask(otuple->src.l3num, otuple->src.u3.ip6, |
93 | info->src_mask.ip6); | |
94 | t->dst = hmark_addr_mask(otuple->src.l3num, rtuple->src.u3.ip6, | |
95 | info->dst_mask.ip6); | |
cf308a1f HS |
96 | |
97 | if (info->flags & XT_HMARK_FLAG(XT_HMARK_METHOD_L3)) | |
98 | return 0; | |
99 | ||
100 | t->proto = nf_ct_protonum(ct); | |
101 | if (t->proto != IPPROTO_ICMP) { | |
d1992b16 HS |
102 | t->uports.b16.src = otuple->src.u.all; |
103 | t->uports.b16.dst = rtuple->src.u.all; | |
104 | hmark_swap_ports(&t->uports, info); | |
cf308a1f HS |
105 | } |
106 | ||
107 | return 0; | |
108 | #else | |
109 | return -1; | |
110 | #endif | |
111 | } | |
112 | ||
d1992b16 HS |
113 | /* This hash function is endian independent, to ensure consistent hashing if |
114 | * the cluster is composed of big and little endian systems. */ | |
cf308a1f HS |
115 | static inline u32 |
116 | hmark_hash(struct hmark_tuple *t, const struct xt_hmark_info *info) | |
117 | { | |
118 | u32 hash; | |
d1992b16 HS |
119 | u32 src = ntohl(t->src); |
120 | u32 dst = ntohl(t->dst); | |
cf308a1f | 121 | |
d1992b16 HS |
122 | if (dst < src) |
123 | swap(src, dst); | |
cf308a1f | 124 | |
d1992b16 | 125 | hash = jhash_3words(src, dst, t->uports.v32, info->hashrnd); |
cf308a1f HS |
126 | hash = hash ^ (t->proto & info->proto_mask); |
127 | ||
8fc54f68 | 128 | return reciprocal_scale(hash, info->hmodulus) + info->hoffset; |
cf308a1f HS |
129 | } |
130 | ||
131 | static void | |
132 | hmark_set_tuple_ports(const struct sk_buff *skb, unsigned int nhoff, | |
133 | struct hmark_tuple *t, const struct xt_hmark_info *info) | |
134 | { | |
135 | int protoff; | |
136 | ||
137 | protoff = proto_ports_offset(t->proto); | |
138 | if (protoff < 0) | |
139 | return; | |
140 | ||
141 | nhoff += protoff; | |
142 | if (skb_copy_bits(skb, nhoff, &t->uports, sizeof(t->uports)) < 0) | |
143 | return; | |
144 | ||
d1992b16 | 145 | hmark_swap_ports(&t->uports, info); |
cf308a1f HS |
146 | } |
147 | ||
148 | #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) | |
149 | static int get_inner6_hdr(const struct sk_buff *skb, int *offset) | |
150 | { | |
151 | struct icmp6hdr *icmp6h, _ih6; | |
152 | ||
153 | icmp6h = skb_header_pointer(skb, *offset, sizeof(_ih6), &_ih6); | |
154 | if (icmp6h == NULL) | |
155 | return 0; | |
156 | ||
157 | if (icmp6h->icmp6_type && icmp6h->icmp6_type < 128) { | |
158 | *offset += sizeof(struct icmp6hdr); | |
159 | return 1; | |
160 | } | |
161 | return 0; | |
162 | } | |
163 | ||
164 | static int | |
165 | hmark_pkt_set_htuple_ipv6(const struct sk_buff *skb, struct hmark_tuple *t, | |
166 | const struct xt_hmark_info *info) | |
167 | { | |
168 | struct ipv6hdr *ip6, _ip6; | |
f8f62675 | 169 | int flag = IP6_FH_F_AUTH; |
cf308a1f HS |
170 | unsigned int nhoff = 0; |
171 | u16 fragoff = 0; | |
172 | int nexthdr; | |
173 | ||
174 | ip6 = (struct ipv6hdr *) (skb->data + skb_network_offset(skb)); | |
175 | nexthdr = ipv6_find_hdr(skb, &nhoff, -1, &fragoff, &flag); | |
176 | if (nexthdr < 0) | |
177 | return 0; | |
178 | /* No need to check for icmp errors on fragments */ | |
f8f62675 | 179 | if ((flag & IP6_FH_F_FRAG) || (nexthdr != IPPROTO_ICMPV6)) |
cf308a1f HS |
180 | goto noicmp; |
181 | /* Use inner header in case of ICMP errors */ | |
182 | if (get_inner6_hdr(skb, &nhoff)) { | |
183 | ip6 = skb_header_pointer(skb, nhoff, sizeof(_ip6), &_ip6); | |
184 | if (ip6 == NULL) | |
185 | return -1; | |
186 | /* If AH present, use SPI like in ESP. */ | |
f8f62675 | 187 | flag = IP6_FH_F_AUTH; |
cf308a1f HS |
188 | nexthdr = ipv6_find_hdr(skb, &nhoff, -1, &fragoff, &flag); |
189 | if (nexthdr < 0) | |
190 | return -1; | |
191 | } | |
192 | noicmp: | |
d1992b16 HS |
193 | t->src = hmark_addr6_mask(ip6->saddr.s6_addr32, info->src_mask.ip6); |
194 | t->dst = hmark_addr6_mask(ip6->daddr.s6_addr32, info->dst_mask.ip6); | |
cf308a1f HS |
195 | |
196 | if (info->flags & XT_HMARK_FLAG(XT_HMARK_METHOD_L3)) | |
197 | return 0; | |
198 | ||
199 | t->proto = nexthdr; | |
200 | if (t->proto == IPPROTO_ICMPV6) | |
201 | return 0; | |
202 | ||
f8f62675 | 203 | if (flag & IP6_FH_F_FRAG) |
cf308a1f HS |
204 | return 0; |
205 | ||
206 | hmark_set_tuple_ports(skb, nhoff, t, info); | |
207 | return 0; | |
208 | } | |
209 | ||
210 | static unsigned int | |
211 | hmark_tg_v6(struct sk_buff *skb, const struct xt_action_param *par) | |
212 | { | |
213 | const struct xt_hmark_info *info = par->targinfo; | |
214 | struct hmark_tuple t; | |
215 | ||
216 | memset(&t, 0, sizeof(struct hmark_tuple)); | |
217 | ||
218 | if (info->flags & XT_HMARK_FLAG(XT_HMARK_CT)) { | |
219 | if (hmark_ct_set_htuple(skb, &t, info) < 0) | |
220 | return XT_CONTINUE; | |
221 | } else { | |
222 | if (hmark_pkt_set_htuple_ipv6(skb, &t, info) < 0) | |
223 | return XT_CONTINUE; | |
224 | } | |
225 | ||
226 | skb->mark = hmark_hash(&t, info); | |
227 | return XT_CONTINUE; | |
228 | } | |
229 | #endif | |
230 | ||
231 | static int get_inner_hdr(const struct sk_buff *skb, int iphsz, int *nhoff) | |
232 | { | |
233 | const struct icmphdr *icmph; | |
234 | struct icmphdr _ih; | |
235 | ||
236 | /* Not enough header? */ | |
237 | icmph = skb_header_pointer(skb, *nhoff + iphsz, sizeof(_ih), &_ih); | |
58618115 | 238 | if (icmph == NULL || icmph->type > NR_ICMP_TYPES) |
cf308a1f HS |
239 | return 0; |
240 | ||
241 | /* Error message? */ | |
242 | if (icmph->type != ICMP_DEST_UNREACH && | |
243 | icmph->type != ICMP_SOURCE_QUENCH && | |
244 | icmph->type != ICMP_TIME_EXCEEDED && | |
245 | icmph->type != ICMP_PARAMETERPROB && | |
246 | icmph->type != ICMP_REDIRECT) | |
247 | return 0; | |
248 | ||
249 | *nhoff += iphsz + sizeof(_ih); | |
250 | return 1; | |
251 | } | |
252 | ||
253 | static int | |
254 | hmark_pkt_set_htuple_ipv4(const struct sk_buff *skb, struct hmark_tuple *t, | |
255 | const struct xt_hmark_info *info) | |
256 | { | |
257 | struct iphdr *ip, _ip; | |
258 | int nhoff = skb_network_offset(skb); | |
259 | ||
260 | ip = (struct iphdr *) (skb->data + nhoff); | |
261 | if (ip->protocol == IPPROTO_ICMP) { | |
262 | /* Use inner header in case of ICMP errors */ | |
263 | if (get_inner_hdr(skb, ip->ihl * 4, &nhoff)) { | |
264 | ip = skb_header_pointer(skb, nhoff, sizeof(_ip), &_ip); | |
265 | if (ip == NULL) | |
266 | return -1; | |
267 | } | |
268 | } | |
269 | ||
d1992b16 HS |
270 | t->src = ip->saddr & info->src_mask.ip; |
271 | t->dst = ip->daddr & info->dst_mask.ip; | |
cf308a1f HS |
272 | |
273 | if (info->flags & XT_HMARK_FLAG(XT_HMARK_METHOD_L3)) | |
274 | return 0; | |
275 | ||
276 | t->proto = ip->protocol; | |
277 | ||
278 | /* ICMP has no ports, skip */ | |
279 | if (t->proto == IPPROTO_ICMP) | |
280 | return 0; | |
281 | ||
282 | /* follow-up fragments don't contain ports, skip all fragments */ | |
283 | if (ip->frag_off & htons(IP_MF | IP_OFFSET)) | |
284 | return 0; | |
285 | ||
286 | hmark_set_tuple_ports(skb, (ip->ihl * 4) + nhoff, t, info); | |
287 | ||
288 | return 0; | |
289 | } | |
290 | ||
291 | static unsigned int | |
292 | hmark_tg_v4(struct sk_buff *skb, const struct xt_action_param *par) | |
293 | { | |
294 | const struct xt_hmark_info *info = par->targinfo; | |
295 | struct hmark_tuple t; | |
296 | ||
297 | memset(&t, 0, sizeof(struct hmark_tuple)); | |
298 | ||
299 | if (info->flags & XT_HMARK_FLAG(XT_HMARK_CT)) { | |
300 | if (hmark_ct_set_htuple(skb, &t, info) < 0) | |
301 | return XT_CONTINUE; | |
302 | } else { | |
303 | if (hmark_pkt_set_htuple_ipv4(skb, &t, info) < 0) | |
304 | return XT_CONTINUE; | |
305 | } | |
306 | ||
307 | skb->mark = hmark_hash(&t, info); | |
308 | return XT_CONTINUE; | |
309 | } | |
310 | ||
311 | static int hmark_tg_check(const struct xt_tgchk_param *par) | |
312 | { | |
313 | const struct xt_hmark_info *info = par->targinfo; | |
c08e5e1e | 314 | const char *errmsg = "proto mask must be zero with L3 mode"; |
cf308a1f | 315 | |
0cc9501f | 316 | if (!info->hmodulus) |
cf308a1f | 317 | return -EINVAL; |
0cc9501f | 318 | |
cf308a1f | 319 | if (info->proto_mask && |
c08e5e1e FW |
320 | (info->flags & XT_HMARK_FLAG(XT_HMARK_METHOD_L3))) |
321 | goto err; | |
322 | ||
cf308a1f HS |
323 | if (info->flags & XT_HMARK_FLAG(XT_HMARK_SPI_MASK) && |
324 | (info->flags & (XT_HMARK_FLAG(XT_HMARK_SPORT_MASK) | | |
0cc9501f | 325 | XT_HMARK_FLAG(XT_HMARK_DPORT_MASK)))) |
cf308a1f | 326 | return -EINVAL; |
0cc9501f | 327 | |
cf308a1f HS |
328 | if (info->flags & XT_HMARK_FLAG(XT_HMARK_SPI) && |
329 | (info->flags & (XT_HMARK_FLAG(XT_HMARK_SPORT) | | |
330 | XT_HMARK_FLAG(XT_HMARK_DPORT)))) { | |
c08e5e1e FW |
331 | errmsg = "spi-set and port-set can't be combined"; |
332 | goto err; | |
cf308a1f HS |
333 | } |
334 | return 0; | |
c08e5e1e FW |
335 | err: |
336 | pr_info_ratelimited("%s\n", errmsg); | |
337 | return -EINVAL; | |
cf308a1f HS |
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); |