1 // SPDX-License-Identifier: GPL-2.0-only
2 #include <linux/kernel.h>
3 #include <linux/init.h>
4 #include <linux/module.h>
5 #include <linux/netfilter.h>
6 #include <linux/rhashtable.h>
8 #include <linux/ipv6.h>
9 #include <linux/netdevice.h>
10 #include <linux/if_ether.h>
13 #include <net/ip6_route.h>
14 #include <net/neighbour.h>
15 #include <net/netfilter/nf_flow_table.h>
16 #include <net/netfilter/nf_conntrack_acct.h>
17 /* For layer 4 checksum field offset. */
18 #include <linux/tcp.h>
19 #include <linux/udp.h>
21 static int nf_flow_state_check(struct flow_offload *flow, int proto,
22 struct sk_buff *skb, unsigned int thoff)
26 if (proto != IPPROTO_TCP)
29 tcph = (void *)(skb_network_header(skb) + thoff);
30 if (unlikely(tcph->fin || tcph->rst)) {
31 flow_offload_teardown(flow);
38 static void nf_flow_nat_ip_tcp(struct sk_buff *skb, unsigned int thoff,
39 __be32 addr, __be32 new_addr)
43 tcph = (void *)(skb_network_header(skb) + thoff);
44 inet_proto_csum_replace4(&tcph->check, skb, addr, new_addr, true);
47 static void nf_flow_nat_ip_udp(struct sk_buff *skb, unsigned int thoff,
48 __be32 addr, __be32 new_addr)
52 udph = (void *)(skb_network_header(skb) + thoff);
53 if (udph->check || skb->ip_summed == CHECKSUM_PARTIAL) {
54 inet_proto_csum_replace4(&udph->check, skb, addr,
57 udph->check = CSUM_MANGLED_0;
61 static void nf_flow_nat_ip_l4proto(struct sk_buff *skb, struct iphdr *iph,
62 unsigned int thoff, __be32 addr,
65 switch (iph->protocol) {
67 nf_flow_nat_ip_tcp(skb, thoff, addr, new_addr);
70 nf_flow_nat_ip_udp(skb, thoff, addr, new_addr);
75 static void nf_flow_snat_ip(const struct flow_offload *flow,
76 struct sk_buff *skb, struct iphdr *iph,
77 unsigned int thoff, enum flow_offload_tuple_dir dir)
79 __be32 addr, new_addr;
82 case FLOW_OFFLOAD_DIR_ORIGINAL:
84 new_addr = flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dst_v4.s_addr;
85 iph->saddr = new_addr;
87 case FLOW_OFFLOAD_DIR_REPLY:
89 new_addr = flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.src_v4.s_addr;
90 iph->daddr = new_addr;
93 csum_replace4(&iph->check, addr, new_addr);
95 nf_flow_nat_ip_l4proto(skb, iph, thoff, addr, new_addr);
98 static void nf_flow_dnat_ip(const struct flow_offload *flow,
99 struct sk_buff *skb, struct iphdr *iph,
100 unsigned int thoff, enum flow_offload_tuple_dir dir)
102 __be32 addr, new_addr;
105 case FLOW_OFFLOAD_DIR_ORIGINAL:
107 new_addr = flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.src_v4.s_addr;
108 iph->daddr = new_addr;
110 case FLOW_OFFLOAD_DIR_REPLY:
112 new_addr = flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.dst_v4.s_addr;
113 iph->saddr = new_addr;
116 csum_replace4(&iph->check, addr, new_addr);
118 nf_flow_nat_ip_l4proto(skb, iph, thoff, addr, new_addr);
121 static void nf_flow_nat_ip(const struct flow_offload *flow, struct sk_buff *skb,
122 unsigned int thoff, enum flow_offload_tuple_dir dir,
125 if (test_bit(NF_FLOW_SNAT, &flow->flags)) {
126 nf_flow_snat_port(flow, skb, thoff, iph->protocol, dir);
127 nf_flow_snat_ip(flow, skb, iph, thoff, dir);
129 if (test_bit(NF_FLOW_DNAT, &flow->flags)) {
130 nf_flow_dnat_port(flow, skb, thoff, iph->protocol, dir);
131 nf_flow_dnat_ip(flow, skb, iph, thoff, dir);
135 static bool ip_has_options(unsigned int thoff)
137 return thoff != sizeof(struct iphdr);
140 static void nf_flow_tuple_encap(struct sk_buff *skb,
141 struct flow_offload_tuple *tuple)
143 struct vlan_ethhdr *veth;
144 struct pppoe_hdr *phdr;
147 if (skb_vlan_tag_present(skb)) {
148 tuple->encap[i].id = skb_vlan_tag_get(skb);
149 tuple->encap[i].proto = skb->vlan_proto;
152 switch (skb->protocol) {
153 case htons(ETH_P_8021Q):
154 veth = (struct vlan_ethhdr *)skb_mac_header(skb);
155 tuple->encap[i].id = ntohs(veth->h_vlan_TCI);
156 tuple->encap[i].proto = skb->protocol;
158 case htons(ETH_P_PPP_SES):
159 phdr = (struct pppoe_hdr *)skb_mac_header(skb);
160 tuple->encap[i].id = ntohs(phdr->sid);
161 tuple->encap[i].proto = skb->protocol;
166 static int nf_flow_tuple_ip(struct sk_buff *skb, const struct net_device *dev,
167 struct flow_offload_tuple *tuple, u32 *hdrsize,
170 struct flow_ports *ports;
175 if (!pskb_may_pull(skb, sizeof(*iph) + offset))
178 iph = (struct iphdr *)(skb_network_header(skb) + offset);
179 thoff = (iph->ihl * 4);
181 if (ip_is_fragment(iph) ||
182 unlikely(ip_has_options(thoff)))
187 ipproto = iph->protocol;
190 *hdrsize = sizeof(struct tcphdr);
193 *hdrsize = sizeof(struct udphdr);
195 #ifdef CONFIG_NF_CT_PROTO_GRE
197 *hdrsize = sizeof(struct gre_base_hdr);
207 if (!pskb_may_pull(skb, thoff + *hdrsize))
213 ports = (struct flow_ports *)(skb_network_header(skb) + thoff);
214 tuple->src_port = ports->source;
215 tuple->dst_port = ports->dest;
218 struct gre_base_hdr *greh;
220 greh = (struct gre_base_hdr *)(skb_network_header(skb) + thoff);
221 if ((greh->flags & GRE_VERSION) != GRE_VERSION_0)
227 iph = (struct iphdr *)(skb_network_header(skb) + offset);
229 tuple->src_v4.s_addr = iph->saddr;
230 tuple->dst_v4.s_addr = iph->daddr;
231 tuple->l3proto = AF_INET;
232 tuple->l4proto = ipproto;
233 tuple->iifidx = dev->ifindex;
234 nf_flow_tuple_encap(skb, tuple);
239 /* Based on ip_exceeds_mtu(). */
240 static bool nf_flow_exceeds_mtu(const struct sk_buff *skb, unsigned int mtu)
245 if (skb_is_gso(skb) && skb_gso_validate_network_len(skb, mtu))
251 static unsigned int nf_flow_xmit_xfrm(struct sk_buff *skb,
252 const struct nf_hook_state *state,
253 struct dst_entry *dst)
256 skb_dst_set_noref(skb, dst);
257 dst_output(state->net, state->sk, skb);
261 static bool nf_flow_skb_encap_protocol(const struct sk_buff *skb, __be16 proto,
264 struct vlan_ethhdr *veth;
266 switch (skb->protocol) {
267 case htons(ETH_P_8021Q):
268 veth = (struct vlan_ethhdr *)skb_mac_header(skb);
269 if (veth->h_vlan_encapsulated_proto == proto) {
270 *offset += VLAN_HLEN;
274 case htons(ETH_P_PPP_SES):
275 if (nf_flow_pppoe_proto(skb) == proto) {
276 *offset += PPPOE_SES_HLEN;
285 static void nf_flow_encap_pop(struct sk_buff *skb,
286 struct flow_offload_tuple_rhash *tuplehash)
288 struct vlan_hdr *vlan_hdr;
291 for (i = 0; i < tuplehash->tuple.encap_num; i++) {
292 if (skb_vlan_tag_present(skb)) {
293 __vlan_hwaccel_clear_tag(skb);
296 switch (skb->protocol) {
297 case htons(ETH_P_8021Q):
298 vlan_hdr = (struct vlan_hdr *)skb->data;
299 __skb_pull(skb, VLAN_HLEN);
300 vlan_set_encap_proto(skb, vlan_hdr);
301 skb_reset_network_header(skb);
303 case htons(ETH_P_PPP_SES):
304 skb->protocol = nf_flow_pppoe_proto(skb);
305 skb_pull(skb, PPPOE_SES_HLEN);
306 skb_reset_network_header(skb);
312 static unsigned int nf_flow_queue_xmit(struct net *net, struct sk_buff *skb,
313 const struct flow_offload_tuple_rhash *tuplehash,
316 struct net_device *outdev;
318 outdev = dev_get_by_index_rcu(net, tuplehash->tuple.out.ifidx);
323 dev_hard_header(skb, skb->dev, type, tuplehash->tuple.out.h_dest,
324 tuplehash->tuple.out.h_source, skb->len);
331 nf_flow_offload_ip_hook(void *priv, struct sk_buff *skb,
332 const struct nf_hook_state *state)
334 struct flow_offload_tuple_rhash *tuplehash;
335 struct nf_flowtable *flow_table = priv;
336 struct flow_offload_tuple tuple = {};
337 enum flow_offload_tuple_dir dir;
338 struct flow_offload *flow;
339 struct net_device *outdev;
340 u32 hdrsize, offset = 0;
341 unsigned int thoff, mtu;
347 if (skb->protocol != htons(ETH_P_IP) &&
348 !nf_flow_skb_encap_protocol(skb, htons(ETH_P_IP), &offset))
351 if (nf_flow_tuple_ip(skb, state->in, &tuple, &hdrsize, offset) < 0)
354 tuplehash = flow_offload_lookup(flow_table, &tuple);
355 if (tuplehash == NULL)
358 dir = tuplehash->tuple.dir;
359 flow = container_of(tuplehash, struct flow_offload, tuplehash[dir]);
361 mtu = flow->tuplehash[dir].tuple.mtu + offset;
362 if (unlikely(nf_flow_exceeds_mtu(skb, mtu)))
365 iph = (struct iphdr *)(skb_network_header(skb) + offset);
366 thoff = (iph->ihl * 4) + offset;
367 if (nf_flow_state_check(flow, iph->protocol, skb, thoff))
370 if (skb_try_make_writable(skb, thoff + hdrsize))
373 flow_offload_refresh(flow_table, flow);
375 nf_flow_encap_pop(skb, tuplehash);
379 nf_flow_nat_ip(flow, skb, thoff, dir, iph);
381 ip_decrease_ttl(iph);
382 skb_clear_tstamp(skb);
384 if (flow_table->flags & NF_FLOWTABLE_COUNTER)
385 nf_ct_acct_update(flow->ct, tuplehash->tuple.dir, skb->len);
387 if (unlikely(tuplehash->tuple.xmit_type == FLOW_OFFLOAD_XMIT_XFRM)) {
388 rt = (struct rtable *)tuplehash->tuple.dst_cache;
389 memset(skb->cb, 0, sizeof(struct inet_skb_parm));
390 IPCB(skb)->iif = skb->dev->ifindex;
391 IPCB(skb)->flags = IPSKB_FORWARDED;
392 return nf_flow_xmit_xfrm(skb, state, &rt->dst);
395 switch (tuplehash->tuple.xmit_type) {
396 case FLOW_OFFLOAD_XMIT_NEIGH:
397 rt = (struct rtable *)tuplehash->tuple.dst_cache;
398 outdev = rt->dst.dev;
400 nexthop = rt_nexthop(rt, flow->tuplehash[!dir].tuple.src_v4.s_addr);
401 skb_dst_set_noref(skb, &rt->dst);
402 neigh_xmit(NEIGH_ARP_TABLE, outdev, &nexthop, skb);
405 case FLOW_OFFLOAD_XMIT_DIRECT:
406 ret = nf_flow_queue_xmit(state->net, skb, tuplehash, ETH_P_IP);
408 flow_offload_teardown(flow);
414 EXPORT_SYMBOL_GPL(nf_flow_offload_ip_hook);
416 static void nf_flow_nat_ipv6_tcp(struct sk_buff *skb, unsigned int thoff,
417 struct in6_addr *addr,
418 struct in6_addr *new_addr,
419 struct ipv6hdr *ip6h)
423 tcph = (void *)(skb_network_header(skb) + thoff);
424 inet_proto_csum_replace16(&tcph->check, skb, addr->s6_addr32,
425 new_addr->s6_addr32, true);
428 static void nf_flow_nat_ipv6_udp(struct sk_buff *skb, unsigned int thoff,
429 struct in6_addr *addr,
430 struct in6_addr *new_addr)
434 udph = (void *)(skb_network_header(skb) + thoff);
435 if (udph->check || skb->ip_summed == CHECKSUM_PARTIAL) {
436 inet_proto_csum_replace16(&udph->check, skb, addr->s6_addr32,
437 new_addr->s6_addr32, true);
439 udph->check = CSUM_MANGLED_0;
443 static void nf_flow_nat_ipv6_l4proto(struct sk_buff *skb, struct ipv6hdr *ip6h,
444 unsigned int thoff, struct in6_addr *addr,
445 struct in6_addr *new_addr)
447 switch (ip6h->nexthdr) {
449 nf_flow_nat_ipv6_tcp(skb, thoff, addr, new_addr, ip6h);
452 nf_flow_nat_ipv6_udp(skb, thoff, addr, new_addr);
457 static void nf_flow_snat_ipv6(const struct flow_offload *flow,
458 struct sk_buff *skb, struct ipv6hdr *ip6h,
460 enum flow_offload_tuple_dir dir)
462 struct in6_addr addr, new_addr;
465 case FLOW_OFFLOAD_DIR_ORIGINAL:
467 new_addr = flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dst_v6;
468 ip6h->saddr = new_addr;
470 case FLOW_OFFLOAD_DIR_REPLY:
472 new_addr = flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.src_v6;
473 ip6h->daddr = new_addr;
477 nf_flow_nat_ipv6_l4proto(skb, ip6h, thoff, &addr, &new_addr);
480 static void nf_flow_dnat_ipv6(const struct flow_offload *flow,
481 struct sk_buff *skb, struct ipv6hdr *ip6h,
483 enum flow_offload_tuple_dir dir)
485 struct in6_addr addr, new_addr;
488 case FLOW_OFFLOAD_DIR_ORIGINAL:
490 new_addr = flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.src_v6;
491 ip6h->daddr = new_addr;
493 case FLOW_OFFLOAD_DIR_REPLY:
495 new_addr = flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.dst_v6;
496 ip6h->saddr = new_addr;
500 nf_flow_nat_ipv6_l4proto(skb, ip6h, thoff, &addr, &new_addr);
503 static void nf_flow_nat_ipv6(const struct flow_offload *flow,
505 enum flow_offload_tuple_dir dir,
506 struct ipv6hdr *ip6h)
508 unsigned int thoff = sizeof(*ip6h);
510 if (test_bit(NF_FLOW_SNAT, &flow->flags)) {
511 nf_flow_snat_port(flow, skb, thoff, ip6h->nexthdr, dir);
512 nf_flow_snat_ipv6(flow, skb, ip6h, thoff, dir);
514 if (test_bit(NF_FLOW_DNAT, &flow->flags)) {
515 nf_flow_dnat_port(flow, skb, thoff, ip6h->nexthdr, dir);
516 nf_flow_dnat_ipv6(flow, skb, ip6h, thoff, dir);
520 static int nf_flow_tuple_ipv6(struct sk_buff *skb, const struct net_device *dev,
521 struct flow_offload_tuple *tuple, u32 *hdrsize,
524 struct flow_ports *ports;
525 struct ipv6hdr *ip6h;
529 thoff = sizeof(*ip6h) + offset;
530 if (!pskb_may_pull(skb, thoff))
533 ip6h = (struct ipv6hdr *)(skb_network_header(skb) + offset);
535 nexthdr = ip6h->nexthdr;
538 *hdrsize = sizeof(struct tcphdr);
541 *hdrsize = sizeof(struct udphdr);
543 #ifdef CONFIG_NF_CT_PROTO_GRE
545 *hdrsize = sizeof(struct gre_base_hdr);
552 if (ip6h->hop_limit <= 1)
555 if (!pskb_may_pull(skb, thoff + *hdrsize))
561 ports = (struct flow_ports *)(skb_network_header(skb) + thoff);
562 tuple->src_port = ports->source;
563 tuple->dst_port = ports->dest;
566 struct gre_base_hdr *greh;
568 greh = (struct gre_base_hdr *)(skb_network_header(skb) + thoff);
569 if ((greh->flags & GRE_VERSION) != GRE_VERSION_0)
575 ip6h = (struct ipv6hdr *)(skb_network_header(skb) + offset);
577 tuple->src_v6 = ip6h->saddr;
578 tuple->dst_v6 = ip6h->daddr;
579 tuple->l3proto = AF_INET6;
580 tuple->l4proto = nexthdr;
581 tuple->iifidx = dev->ifindex;
582 nf_flow_tuple_encap(skb, tuple);
588 nf_flow_offload_ipv6_hook(void *priv, struct sk_buff *skb,
589 const struct nf_hook_state *state)
591 struct flow_offload_tuple_rhash *tuplehash;
592 struct nf_flowtable *flow_table = priv;
593 struct flow_offload_tuple tuple = {};
594 enum flow_offload_tuple_dir dir;
595 const struct in6_addr *nexthop;
596 struct flow_offload *flow;
597 struct net_device *outdev;
598 unsigned int thoff, mtu;
599 u32 hdrsize, offset = 0;
600 struct ipv6hdr *ip6h;
604 if (skb->protocol != htons(ETH_P_IPV6) &&
605 !nf_flow_skb_encap_protocol(skb, htons(ETH_P_IPV6), &offset))
608 if (nf_flow_tuple_ipv6(skb, state->in, &tuple, &hdrsize, offset) < 0)
611 tuplehash = flow_offload_lookup(flow_table, &tuple);
612 if (tuplehash == NULL)
615 dir = tuplehash->tuple.dir;
616 flow = container_of(tuplehash, struct flow_offload, tuplehash[dir]);
618 mtu = flow->tuplehash[dir].tuple.mtu + offset;
619 if (unlikely(nf_flow_exceeds_mtu(skb, mtu)))
622 ip6h = (struct ipv6hdr *)(skb_network_header(skb) + offset);
623 thoff = sizeof(*ip6h) + offset;
624 if (nf_flow_state_check(flow, ip6h->nexthdr, skb, thoff))
627 if (skb_try_make_writable(skb, thoff + hdrsize))
630 flow_offload_refresh(flow_table, flow);
632 nf_flow_encap_pop(skb, tuplehash);
634 ip6h = ipv6_hdr(skb);
635 nf_flow_nat_ipv6(flow, skb, dir, ip6h);
638 skb_clear_tstamp(skb);
640 if (flow_table->flags & NF_FLOWTABLE_COUNTER)
641 nf_ct_acct_update(flow->ct, tuplehash->tuple.dir, skb->len);
643 if (unlikely(tuplehash->tuple.xmit_type == FLOW_OFFLOAD_XMIT_XFRM)) {
644 rt = (struct rt6_info *)tuplehash->tuple.dst_cache;
645 memset(skb->cb, 0, sizeof(struct inet6_skb_parm));
646 IP6CB(skb)->iif = skb->dev->ifindex;
647 IP6CB(skb)->flags = IP6SKB_FORWARDED;
648 return nf_flow_xmit_xfrm(skb, state, &rt->dst);
651 switch (tuplehash->tuple.xmit_type) {
652 case FLOW_OFFLOAD_XMIT_NEIGH:
653 rt = (struct rt6_info *)tuplehash->tuple.dst_cache;
654 outdev = rt->dst.dev;
656 nexthop = rt6_nexthop(rt, &flow->tuplehash[!dir].tuple.src_v6);
657 skb_dst_set_noref(skb, &rt->dst);
658 neigh_xmit(NEIGH_ND_TABLE, outdev, nexthop, skb);
661 case FLOW_OFFLOAD_XMIT_DIRECT:
662 ret = nf_flow_queue_xmit(state->net, skb, tuplehash, ETH_P_IPV6);
664 flow_offload_teardown(flow);
670 EXPORT_SYMBOL_GPL(nf_flow_offload_ipv6_hook);