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9#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10
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
27MODULE_LICENSE("GPL");
28MODULE_AUTHOR("Hans Schillstrom <hans.schillstrom@ericsson.com>");
29MODULE_DESCRIPTION("Xtables: packet marking using hash calculation");
30MODULE_ALIAS("ipt_HMARK");
31MODULE_ALIAS("ip6t_HMARK");
32
33struct hmark_tuple {
34 __be32 src;
35 __be32 dst;
36 union hmark_ports uports;
37 u8 proto;
38};
39
40static inline __be32 hmark_addr6_mask(const __be32 *addr32, const __be32 *mask)
41{
42 return (addr32[0] & mask[0]) ^
43 (addr32[1] & mask[1]) ^
44 (addr32[2] & mask[2]) ^
45 (addr32[3] & mask[3]);
46}
47
48static inline __be32
49hmark_addr_mask(int l3num, const __be32 *addr32, const __be32 *mask)
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
60static 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
76static int
77hmark_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
86 if (ct == NULL)
87 return -1;
88
89 otuple = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
90 rtuple = &ct->tuplehash[IP_CT_DIR_REPLY].tuple;
91
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);
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) {
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);
105 }
106
107 return 0;
108#else
109 return -1;
110#endif
111}
112
113
114
115static inline u32
116hmark_hash(struct hmark_tuple *t, const struct xt_hmark_info *info)
117{
118 u32 hash;
119 u32 src = ntohl(t->src);
120 u32 dst = ntohl(t->dst);
121
122 if (dst < src)
123 swap(src, dst);
124
125 hash = jhash_3words(src, dst, t->uports.v32, info->hashrnd);
126 hash = hash ^ (t->proto & info->proto_mask);
127
128 return reciprocal_scale(hash, info->hmodulus) + info->hoffset;
129}
130
131static void
132hmark_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
145 hmark_swap_ports(&t->uports, info);
146}
147
148#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
149static 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
164static int
165hmark_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;
169 int flag = IP6_FH_F_AUTH;
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
179 if ((flag & IP6_FH_F_FRAG) || (nexthdr != IPPROTO_ICMPV6))
180 goto noicmp;
181
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
187 flag = IP6_FH_F_AUTH;
188 nexthdr = ipv6_find_hdr(skb, &nhoff, -1, &fragoff, &flag);
189 if (nexthdr < 0)
190 return -1;
191 }
192noicmp:
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);
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
203 if (flag & IP6_FH_F_FRAG)
204 return 0;
205
206 hmark_set_tuple_ports(skb, nhoff, t, info);
207 return 0;
208}
209
210static unsigned int
211hmark_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
231static 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
237 icmph = skb_header_pointer(skb, *nhoff + iphsz, sizeof(_ih), &_ih);
238 if (icmph == NULL || icmph->type > NR_ICMP_TYPES)
239 return 0;
240
241
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
253static int
254hmark_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
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
270 t->src = ip->saddr & info->src_mask.ip;
271 t->dst = ip->daddr & info->dst_mask.ip;
272
273 if (info->flags & XT_HMARK_FLAG(XT_HMARK_METHOD_L3))
274 return 0;
275
276 t->proto = ip->protocol;
277
278
279 if (t->proto == IPPROTO_ICMP)
280 return 0;
281
282
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
291static unsigned int
292hmark_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
311static int hmark_tg_check(const struct xt_tgchk_param *par)
312{
313 const struct xt_hmark_info *info = par->targinfo;
314 const char *errmsg = "proto mask must be zero with L3 mode";
315
316 if (!info->hmodulus)
317 return -EINVAL;
318
319 if (info->proto_mask &&
320 (info->flags & XT_HMARK_FLAG(XT_HMARK_METHOD_L3)))
321 goto err;
322
323 if (info->flags & XT_HMARK_FLAG(XT_HMARK_SPI_MASK) &&
324 (info->flags & (XT_HMARK_FLAG(XT_HMARK_SPORT_MASK) |
325 XT_HMARK_FLAG(XT_HMARK_DPORT_MASK))))
326 return -EINVAL;
327
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)))) {
331 errmsg = "spi-set and port-set can't be combined";
332 goto err;
333 }
334 return 0;
335err:
336 pr_info_ratelimited("%s\n", errmsg);
337 return -EINVAL;
338}
339
340static 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
361static int __init hmark_tg_init(void)
362{
363 return xt_register_targets(hmark_tg_reg, ARRAY_SIZE(hmark_tg_reg));
364}
365
366static void __exit hmark_tg_exit(void)
367{
368 xt_unregister_targets(hmark_tg_reg, ARRAY_SIZE(hmark_tg_reg));
369}
370
371module_init(hmark_tg_init);
372module_exit(hmark_tg_exit);
373
