~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/net/netfilter/nf_flow_table_ip.c

Version: ~ [ linux-5.11-rc3 ] ~ [ linux-5.10.7 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.89 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.167 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.215 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.251 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.251 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.85 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 #include <linux/kernel.h>
  2 #include <linux/init.h>
  3 #include <linux/module.h>
  4 #include <linux/netfilter.h>
  5 #include <linux/rhashtable.h>
  6 #include <linux/ip.h>
  7 #include <linux/ipv6.h>
  8 #include <linux/netdevice.h>
  9 #include <net/ip.h>
 10 #include <net/ipv6.h>
 11 #include <net/ip6_route.h>
 12 #include <net/neighbour.h>
 13 #include <net/netfilter/nf_flow_table.h>
 14 /* For layer 4 checksum field offset. */
 15 #include <linux/tcp.h>
 16 #include <linux/udp.h>
 17 
 18 static int nf_flow_state_check(struct flow_offload *flow, int proto,
 19                                struct sk_buff *skb, unsigned int thoff)
 20 {
 21         struct tcphdr *tcph;
 22 
 23         if (proto != IPPROTO_TCP)
 24                 return 0;
 25 
 26         if (!pskb_may_pull(skb, thoff + sizeof(*tcph)))
 27                 return -1;
 28 
 29         tcph = (void *)(skb_network_header(skb) + thoff);
 30         if (unlikely(tcph->fin || tcph->rst)) {
 31                 flow_offload_teardown(flow);
 32                 return -1;
 33         }
 34 
 35         return 0;
 36 }
 37 
 38 static int nf_flow_nat_ip_tcp(struct sk_buff *skb, unsigned int thoff,
 39                               __be32 addr, __be32 new_addr)
 40 {
 41         struct tcphdr *tcph;
 42 
 43         if (!pskb_may_pull(skb, thoff + sizeof(*tcph)) ||
 44             skb_try_make_writable(skb, thoff + sizeof(*tcph)))
 45                 return -1;
 46 
 47         tcph = (void *)(skb_network_header(skb) + thoff);
 48         inet_proto_csum_replace4(&tcph->check, skb, addr, new_addr, true);
 49 
 50         return 0;
 51 }
 52 
 53 static int nf_flow_nat_ip_udp(struct sk_buff *skb, unsigned int thoff,
 54                               __be32 addr, __be32 new_addr)
 55 {
 56         struct udphdr *udph;
 57 
 58         if (!pskb_may_pull(skb, thoff + sizeof(*udph)) ||
 59             skb_try_make_writable(skb, thoff + sizeof(*udph)))
 60                 return -1;
 61 
 62         udph = (void *)(skb_network_header(skb) + thoff);
 63         if (udph->check || skb->ip_summed == CHECKSUM_PARTIAL) {
 64                 inet_proto_csum_replace4(&udph->check, skb, addr,
 65                                          new_addr, true);
 66                 if (!udph->check)
 67                         udph->check = CSUM_MANGLED_0;
 68         }
 69 
 70         return 0;
 71 }
 72 
 73 static int nf_flow_nat_ip_l4proto(struct sk_buff *skb, struct iphdr *iph,
 74                                   unsigned int thoff, __be32 addr,
 75                                   __be32 new_addr)
 76 {
 77         switch (iph->protocol) {
 78         case IPPROTO_TCP:
 79                 if (nf_flow_nat_ip_tcp(skb, thoff, addr, new_addr) < 0)
 80                         return NF_DROP;
 81                 break;
 82         case IPPROTO_UDP:
 83                 if (nf_flow_nat_ip_udp(skb, thoff, addr, new_addr) < 0)
 84                         return NF_DROP;
 85                 break;
 86         }
 87 
 88         return 0;
 89 }
 90 
 91 static int nf_flow_snat_ip(const struct flow_offload *flow, struct sk_buff *skb,
 92                            struct iphdr *iph, unsigned int thoff,
 93                            enum flow_offload_tuple_dir dir)
 94 {
 95         __be32 addr, new_addr;
 96 
 97         switch (dir) {
 98         case FLOW_OFFLOAD_DIR_ORIGINAL:
 99                 addr = iph->saddr;
100                 new_addr = flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dst_v4.s_addr;
101                 iph->saddr = new_addr;
102                 break;
103         case FLOW_OFFLOAD_DIR_REPLY:
104                 addr = iph->daddr;
105                 new_addr = flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.src_v4.s_addr;
106                 iph->daddr = new_addr;
107                 break;
108         default:
109                 return -1;
110         }
111         csum_replace4(&iph->check, addr, new_addr);
112 
113         return nf_flow_nat_ip_l4proto(skb, iph, thoff, addr, new_addr);
114 }
115 
116 static int nf_flow_dnat_ip(const struct flow_offload *flow, struct sk_buff *skb,
117                            struct iphdr *iph, unsigned int thoff,
118                            enum flow_offload_tuple_dir dir)
119 {
120         __be32 addr, new_addr;
121 
122         switch (dir) {
123         case FLOW_OFFLOAD_DIR_ORIGINAL:
124                 addr = iph->daddr;
125                 new_addr = flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.src_v4.s_addr;
126                 iph->daddr = new_addr;
127                 break;
128         case FLOW_OFFLOAD_DIR_REPLY:
129                 addr = iph->saddr;
130                 new_addr = flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.dst_v4.s_addr;
131                 iph->saddr = new_addr;
132                 break;
133         default:
134                 return -1;
135         }
136         csum_replace4(&iph->check, addr, new_addr);
137 
138         return nf_flow_nat_ip_l4proto(skb, iph, thoff, addr, new_addr);
139 }
140 
141 static int nf_flow_nat_ip(const struct flow_offload *flow, struct sk_buff *skb,
142                           unsigned int thoff, enum flow_offload_tuple_dir dir)
143 {
144         struct iphdr *iph = ip_hdr(skb);
145 
146         if (flow->flags & FLOW_OFFLOAD_SNAT &&
147             (nf_flow_snat_port(flow, skb, thoff, iph->protocol, dir) < 0 ||
148              nf_flow_snat_ip(flow, skb, iph, thoff, dir) < 0))
149                 return -1;
150         if (flow->flags & FLOW_OFFLOAD_DNAT &&
151             (nf_flow_dnat_port(flow, skb, thoff, iph->protocol, dir) < 0 ||
152              nf_flow_dnat_ip(flow, skb, iph, thoff, dir) < 0))
153                 return -1;
154 
155         return 0;
156 }
157 
158 static bool ip_has_options(unsigned int thoff)
159 {
160         return thoff != sizeof(struct iphdr);
161 }
162 
163 static int nf_flow_tuple_ip(struct sk_buff *skb, const struct net_device *dev,
164                             struct flow_offload_tuple *tuple)
165 {
166         struct flow_ports *ports;
167         unsigned int thoff;
168         struct iphdr *iph;
169 
170         if (!pskb_may_pull(skb, sizeof(*iph)))
171                 return -1;
172 
173         iph = ip_hdr(skb);
174         thoff = iph->ihl * 4;
175 
176         if (ip_is_fragment(iph) ||
177             unlikely(ip_has_options(thoff)))
178                 return -1;
179 
180         if (iph->protocol != IPPROTO_TCP &&
181             iph->protocol != IPPROTO_UDP)
182                 return -1;
183 
184         thoff = iph->ihl * 4;
185         if (!pskb_may_pull(skb, thoff + sizeof(*ports)))
186                 return -1;
187 
188         ports = (struct flow_ports *)(skb_network_header(skb) + thoff);
189 
190         tuple->src_v4.s_addr    = iph->saddr;
191         tuple->dst_v4.s_addr    = iph->daddr;
192         tuple->src_port         = ports->source;
193         tuple->dst_port         = ports->dest;
194         tuple->l3proto          = AF_INET;
195         tuple->l4proto          = iph->protocol;
196         tuple->iifidx           = dev->ifindex;
197 
198         return 0;
199 }
200 
201 /* Based on ip_exceeds_mtu(). */
202 static bool nf_flow_exceeds_mtu(const struct sk_buff *skb, unsigned int mtu)
203 {
204         if (skb->len <= mtu)
205                 return false;
206 
207         if (skb_is_gso(skb) && skb_gso_validate_network_len(skb, mtu))
208                 return false;
209 
210         return true;
211 }
212 
213 unsigned int
214 nf_flow_offload_ip_hook(void *priv, struct sk_buff *skb,
215                         const struct nf_hook_state *state)
216 {
217         struct flow_offload_tuple_rhash *tuplehash;
218         struct nf_flowtable *flow_table = priv;
219         struct flow_offload_tuple tuple = {};
220         enum flow_offload_tuple_dir dir;
221         struct flow_offload *flow;
222         struct net_device *outdev;
223         struct rtable *rt;
224         unsigned int thoff;
225         struct iphdr *iph;
226         __be32 nexthop;
227 
228         if (skb->protocol != htons(ETH_P_IP))
229                 return NF_ACCEPT;
230 
231         if (nf_flow_tuple_ip(skb, state->in, &tuple) < 0)
232                 return NF_ACCEPT;
233 
234         tuplehash = flow_offload_lookup(flow_table, &tuple);
235         if (tuplehash == NULL)
236                 return NF_ACCEPT;
237 
238         outdev = dev_get_by_index_rcu(state->net, tuplehash->tuple.oifidx);
239         if (!outdev)
240                 return NF_ACCEPT;
241 
242         dir = tuplehash->tuple.dir;
243         flow = container_of(tuplehash, struct flow_offload, tuplehash[dir]);
244         rt = (struct rtable *)flow->tuplehash[dir].tuple.dst_cache;
245 
246         if (unlikely(nf_flow_exceeds_mtu(skb, flow->tuplehash[dir].tuple.mtu)) &&
247             (ip_hdr(skb)->frag_off & htons(IP_DF)) != 0)
248                 return NF_ACCEPT;
249 
250         if (skb_try_make_writable(skb, sizeof(*iph)))
251                 return NF_DROP;
252 
253         thoff = ip_hdr(skb)->ihl * 4;
254         if (nf_flow_state_check(flow, ip_hdr(skb)->protocol, skb, thoff))
255                 return NF_ACCEPT;
256 
257         if (flow->flags & (FLOW_OFFLOAD_SNAT | FLOW_OFFLOAD_DNAT) &&
258             nf_flow_nat_ip(flow, skb, thoff, dir) < 0)
259                 return NF_DROP;
260 
261         flow->timeout = (u32)jiffies + NF_FLOW_TIMEOUT;
262         iph = ip_hdr(skb);
263         ip_decrease_ttl(iph);
264 
265         skb->dev = outdev;
266         nexthop = rt_nexthop(rt, flow->tuplehash[!dir].tuple.src_v4.s_addr);
267         skb_dst_set_noref(skb, &rt->dst);
268         neigh_xmit(NEIGH_ARP_TABLE, outdev, &nexthop, skb);
269 
270         return NF_STOLEN;
271 }
272 EXPORT_SYMBOL_GPL(nf_flow_offload_ip_hook);
273 
274 static int nf_flow_nat_ipv6_tcp(struct sk_buff *skb, unsigned int thoff,
275                                 struct in6_addr *addr,
276                                 struct in6_addr *new_addr)
277 {
278         struct tcphdr *tcph;
279 
280         if (!pskb_may_pull(skb, thoff + sizeof(*tcph)) ||
281             skb_try_make_writable(skb, thoff + sizeof(*tcph)))
282                 return -1;
283 
284         tcph = (void *)(skb_network_header(skb) + thoff);
285         inet_proto_csum_replace16(&tcph->check, skb, addr->s6_addr32,
286                                   new_addr->s6_addr32, true);
287 
288         return 0;
289 }
290 
291 static int nf_flow_nat_ipv6_udp(struct sk_buff *skb, unsigned int thoff,
292                                 struct in6_addr *addr,
293                                 struct in6_addr *new_addr)
294 {
295         struct udphdr *udph;
296 
297         if (!pskb_may_pull(skb, thoff + sizeof(*udph)) ||
298             skb_try_make_writable(skb, thoff + sizeof(*udph)))
299                 return -1;
300 
301         udph = (void *)(skb_network_header(skb) + thoff);
302         if (udph->check || skb->ip_summed == CHECKSUM_PARTIAL) {
303                 inet_proto_csum_replace16(&udph->check, skb, addr->s6_addr32,
304                                           new_addr->s6_addr32, true);
305                 if (!udph->check)
306                         udph->check = CSUM_MANGLED_0;
307         }
308 
309         return 0;
310 }
311 
312 static int nf_flow_nat_ipv6_l4proto(struct sk_buff *skb, struct ipv6hdr *ip6h,
313                                     unsigned int thoff, struct in6_addr *addr,
314                                     struct in6_addr *new_addr)
315 {
316         switch (ip6h->nexthdr) {
317         case IPPROTO_TCP:
318                 if (nf_flow_nat_ipv6_tcp(skb, thoff, addr, new_addr) < 0)
319                         return NF_DROP;
320                 break;
321         case IPPROTO_UDP:
322                 if (nf_flow_nat_ipv6_udp(skb, thoff, addr, new_addr) < 0)
323                         return NF_DROP;
324                 break;
325         }
326 
327         return 0;
328 }
329 
330 static int nf_flow_snat_ipv6(const struct flow_offload *flow,
331                              struct sk_buff *skb, struct ipv6hdr *ip6h,
332                              unsigned int thoff,
333                              enum flow_offload_tuple_dir dir)
334 {
335         struct in6_addr addr, new_addr;
336 
337         switch (dir) {
338         case FLOW_OFFLOAD_DIR_ORIGINAL:
339                 addr = ip6h->saddr;
340                 new_addr = flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dst_v6;
341                 ip6h->saddr = new_addr;
342                 break;
343         case FLOW_OFFLOAD_DIR_REPLY:
344                 addr = ip6h->daddr;
345                 new_addr = flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.src_v6;
346                 ip6h->daddr = new_addr;
347                 break;
348         default:
349                 return -1;
350         }
351 
352         return nf_flow_nat_ipv6_l4proto(skb, ip6h, thoff, &addr, &new_addr);
353 }
354 
355 static int nf_flow_dnat_ipv6(const struct flow_offload *flow,
356                              struct sk_buff *skb, struct ipv6hdr *ip6h,
357                              unsigned int thoff,
358                              enum flow_offload_tuple_dir dir)
359 {
360         struct in6_addr addr, new_addr;
361 
362         switch (dir) {
363         case FLOW_OFFLOAD_DIR_ORIGINAL:
364                 addr = ip6h->daddr;
365                 new_addr = flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.src_v6;
366                 ip6h->daddr = new_addr;
367                 break;
368         case FLOW_OFFLOAD_DIR_REPLY:
369                 addr = ip6h->saddr;
370                 new_addr = flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.dst_v6;
371                 ip6h->saddr = new_addr;
372                 break;
373         default:
374                 return -1;
375         }
376 
377         return nf_flow_nat_ipv6_l4proto(skb, ip6h, thoff, &addr, &new_addr);
378 }
379 
380 static int nf_flow_nat_ipv6(const struct flow_offload *flow,
381                             struct sk_buff *skb,
382                             enum flow_offload_tuple_dir dir)
383 {
384         struct ipv6hdr *ip6h = ipv6_hdr(skb);
385         unsigned int thoff = sizeof(*ip6h);
386 
387         if (flow->flags & FLOW_OFFLOAD_SNAT &&
388             (nf_flow_snat_port(flow, skb, thoff, ip6h->nexthdr, dir) < 0 ||
389              nf_flow_snat_ipv6(flow, skb, ip6h, thoff, dir) < 0))
390                 return -1;
391         if (flow->flags & FLOW_OFFLOAD_DNAT &&
392             (nf_flow_dnat_port(flow, skb, thoff, ip6h->nexthdr, dir) < 0 ||
393              nf_flow_dnat_ipv6(flow, skb, ip6h, thoff, dir) < 0))
394                 return -1;
395 
396         return 0;
397 }
398 
399 static int nf_flow_tuple_ipv6(struct sk_buff *skb, const struct net_device *dev,
400                               struct flow_offload_tuple *tuple)
401 {
402         struct flow_ports *ports;
403         struct ipv6hdr *ip6h;
404         unsigned int thoff;
405 
406         if (!pskb_may_pull(skb, sizeof(*ip6h)))
407                 return -1;
408 
409         ip6h = ipv6_hdr(skb);
410 
411         if (ip6h->nexthdr != IPPROTO_TCP &&
412             ip6h->nexthdr != IPPROTO_UDP)
413                 return -1;
414 
415         thoff = sizeof(*ip6h);
416         if (!pskb_may_pull(skb, thoff + sizeof(*ports)))
417                 return -1;
418 
419         ports = (struct flow_ports *)(skb_network_header(skb) + thoff);
420 
421         tuple->src_v6           = ip6h->saddr;
422         tuple->dst_v6           = ip6h->daddr;
423         tuple->src_port         = ports->source;
424         tuple->dst_port         = ports->dest;
425         tuple->l3proto          = AF_INET6;
426         tuple->l4proto          = ip6h->nexthdr;
427         tuple->iifidx           = dev->ifindex;
428 
429         return 0;
430 }
431 
432 unsigned int
433 nf_flow_offload_ipv6_hook(void *priv, struct sk_buff *skb,
434                           const struct nf_hook_state *state)
435 {
436         struct flow_offload_tuple_rhash *tuplehash;
437         struct nf_flowtable *flow_table = priv;
438         struct flow_offload_tuple tuple = {};
439         enum flow_offload_tuple_dir dir;
440         struct flow_offload *flow;
441         struct net_device *outdev;
442         struct in6_addr *nexthop;
443         struct ipv6hdr *ip6h;
444         struct rt6_info *rt;
445 
446         if (skb->protocol != htons(ETH_P_IPV6))
447                 return NF_ACCEPT;
448 
449         if (nf_flow_tuple_ipv6(skb, state->in, &tuple) < 0)
450                 return NF_ACCEPT;
451 
452         tuplehash = flow_offload_lookup(flow_table, &tuple);
453         if (tuplehash == NULL)
454                 return NF_ACCEPT;
455 
456         outdev = dev_get_by_index_rcu(state->net, tuplehash->tuple.oifidx);
457         if (!outdev)
458                 return NF_ACCEPT;
459 
460         dir = tuplehash->tuple.dir;
461         flow = container_of(tuplehash, struct flow_offload, tuplehash[dir]);
462         rt = (struct rt6_info *)flow->tuplehash[dir].tuple.dst_cache;
463 
464         if (unlikely(nf_flow_exceeds_mtu(skb, flow->tuplehash[dir].tuple.mtu)))
465                 return NF_ACCEPT;
466 
467         if (nf_flow_state_check(flow, ipv6_hdr(skb)->nexthdr, skb,
468                                 sizeof(*ip6h)))
469                 return NF_ACCEPT;
470 
471         if (skb_try_make_writable(skb, sizeof(*ip6h)))
472                 return NF_DROP;
473 
474         if (flow->flags & (FLOW_OFFLOAD_SNAT | FLOW_OFFLOAD_DNAT) &&
475             nf_flow_nat_ipv6(flow, skb, dir) < 0)
476                 return NF_DROP;
477 
478         flow->timeout = (u32)jiffies + NF_FLOW_TIMEOUT;
479         ip6h = ipv6_hdr(skb);
480         ip6h->hop_limit--;
481 
482         skb->dev = outdev;
483         nexthop = rt6_nexthop(rt, &flow->tuplehash[!dir].tuple.src_v6);
484         skb_dst_set_noref(skb, &rt->dst);
485         neigh_xmit(NEIGH_ND_TABLE, outdev, nexthop, skb);
486 
487         return NF_STOLEN;
488 }
489 EXPORT_SYMBOL_GPL(nf_flow_offload_ipv6_hook);
490 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp