2 * SR-IPv6 implementation
5 * David Lebrun <david.lebrun@uclouvain.be>
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * as published by the Free Software Foundation; either version
11 * 2 of the License, or (at your option) any later version.
14 #include <linux/types.h>
15 #include <linux/skbuff.h>
16 #include <linux/net.h>
17 #include <linux/module.h>
19 #include <net/ip_tunnels.h>
20 #include <net/lwtunnel.h>
21 #include <net/netevent.h>
22 #include <net/netns/generic.h>
23 #include <net/ip6_fib.h>
24 #include <net/route.h>
26 #include <linux/seg6.h>
27 #include <linux/seg6_iptunnel.h>
28 #include <net/addrconf.h>
29 #include <net/ip6_route.h>
30 #include <net/dst_cache.h>
31 #ifdef CONFIG_IPV6_SEG6_HMAC
32 #include <net/seg6_hmac.h>
36 struct dst_cache cache;
37 struct seg6_iptunnel_encap tuninfo[0];
40 static inline struct seg6_lwt *seg6_lwt_lwtunnel(struct lwtunnel_state *lwt)
42 return (struct seg6_lwt *)lwt->data;
45 static inline struct seg6_iptunnel_encap *
46 seg6_encap_lwtunnel(struct lwtunnel_state *lwt)
48 return seg6_lwt_lwtunnel(lwt)->tuninfo;
51 static const struct nla_policy seg6_iptunnel_policy[SEG6_IPTUNNEL_MAX + 1] = {
52 [SEG6_IPTUNNEL_SRH] = { .type = NLA_BINARY },
55 static int nla_put_srh(struct sk_buff *skb, int attrtype,
56 struct seg6_iptunnel_encap *tuninfo)
58 struct seg6_iptunnel_encap *data;
62 len = SEG6_IPTUN_ENCAP_SIZE(tuninfo);
64 nla = nla_reserve(skb, attrtype, len);
69 memcpy(data, tuninfo, len);
74 static void set_tun_src(struct net *net, struct net_device *dev,
75 struct in6_addr *daddr, struct in6_addr *saddr)
77 struct seg6_pernet_data *sdata = seg6_pernet(net);
78 struct in6_addr *tun_src;
82 tun_src = rcu_dereference(sdata->tun_src);
84 if (!ipv6_addr_any(tun_src)) {
85 memcpy(saddr, tun_src, sizeof(struct in6_addr));
87 ipv6_dev_get_saddr(net, dev, daddr, IPV6_PREFER_SRC_PUBLIC,
94 /* encapsulate an IPv6 packet within an outer IPv6 header with a given SRH */
95 int seg6_do_srh_encap(struct sk_buff *skb, struct ipv6_sr_hdr *osrh, int proto)
97 struct dst_entry *dst = skb_dst(skb);
98 struct net *net = dev_net(dst->dev);
99 struct ipv6hdr *hdr, *inner_hdr;
100 struct ipv6_sr_hdr *isrh;
101 int hdrlen, tot_len, err;
103 hdrlen = (osrh->hdrlen + 1) << 3;
104 tot_len = hdrlen + sizeof(*hdr);
106 err = skb_cow_head(skb, tot_len + skb->mac_len);
110 inner_hdr = ipv6_hdr(skb);
112 skb_push(skb, tot_len);
113 skb_reset_network_header(skb);
114 skb_mac_header_rebuild(skb);
117 /* inherit tc, flowlabel and hlim
118 * hlim will be decremented in ip6_forward() afterwards and
119 * decapsulation will overwrite inner hlim with outer hlim
122 if (skb->protocol == htons(ETH_P_IPV6)) {
123 ip6_flow_hdr(hdr, ip6_tclass(ip6_flowinfo(inner_hdr)),
124 ip6_flowlabel(inner_hdr));
125 hdr->hop_limit = inner_hdr->hop_limit;
127 ip6_flow_hdr(hdr, 0, 0);
128 hdr->hop_limit = ip6_dst_hoplimit(skb_dst(skb));
130 memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
133 hdr->nexthdr = NEXTHDR_ROUTING;
135 isrh = (void *)hdr + sizeof(*hdr);
136 memcpy(isrh, osrh, hdrlen);
138 isrh->nexthdr = proto;
140 hdr->daddr = isrh->segments[isrh->first_segment];
141 set_tun_src(net, dst->dev, &hdr->daddr, &hdr->saddr);
143 #ifdef CONFIG_IPV6_SEG6_HMAC
144 if (sr_has_hmac(isrh)) {
145 err = seg6_push_hmac(net, &hdr->saddr, isrh);
151 skb_postpush_rcsum(skb, hdr, tot_len);
155 EXPORT_SYMBOL_GPL(seg6_do_srh_encap);
157 /* insert an SRH within an IPv6 packet, just after the IPv6 header */
158 int seg6_do_srh_inline(struct sk_buff *skb, struct ipv6_sr_hdr *osrh)
160 struct ipv6hdr *hdr, *oldhdr;
161 struct ipv6_sr_hdr *isrh;
164 hdrlen = (osrh->hdrlen + 1) << 3;
166 err = skb_cow_head(skb, hdrlen + skb->mac_len);
170 oldhdr = ipv6_hdr(skb);
172 skb_pull(skb, sizeof(struct ipv6hdr));
173 skb_postpull_rcsum(skb, skb_network_header(skb),
174 sizeof(struct ipv6hdr));
176 skb_push(skb, sizeof(struct ipv6hdr) + hdrlen);
177 skb_reset_network_header(skb);
178 skb_mac_header_rebuild(skb);
182 memmove(hdr, oldhdr, sizeof(*hdr));
184 isrh = (void *)hdr + sizeof(*hdr);
185 memcpy(isrh, osrh, hdrlen);
187 isrh->nexthdr = hdr->nexthdr;
188 hdr->nexthdr = NEXTHDR_ROUTING;
190 isrh->segments[0] = hdr->daddr;
191 hdr->daddr = isrh->segments[isrh->first_segment];
193 #ifdef CONFIG_IPV6_SEG6_HMAC
194 if (sr_has_hmac(isrh)) {
195 struct net *net = dev_net(skb_dst(skb)->dev);
197 err = seg6_push_hmac(net, &hdr->saddr, isrh);
203 skb_postpush_rcsum(skb, hdr, sizeof(struct ipv6hdr) + hdrlen);
207 EXPORT_SYMBOL_GPL(seg6_do_srh_inline);
209 static int seg6_do_srh(struct sk_buff *skb)
211 struct dst_entry *dst = skb_dst(skb);
212 struct seg6_iptunnel_encap *tinfo;
215 tinfo = seg6_encap_lwtunnel(dst->lwtstate);
217 switch (tinfo->mode) {
218 case SEG6_IPTUN_MODE_INLINE:
219 if (skb->protocol != htons(ETH_P_IPV6))
222 err = seg6_do_srh_inline(skb, tinfo->srh);
226 case SEG6_IPTUN_MODE_ENCAP:
227 err = iptunnel_handle_offloads(skb, SKB_GSO_IPXIP6);
231 if (skb->protocol == htons(ETH_P_IPV6))
232 proto = IPPROTO_IPV6;
233 else if (skb->protocol == htons(ETH_P_IP))
234 proto = IPPROTO_IPIP;
238 err = seg6_do_srh_encap(skb, tinfo->srh, proto);
242 skb_set_inner_transport_header(skb, skb_transport_offset(skb));
243 skb_set_inner_protocol(skb, skb->protocol);
244 skb->protocol = htons(ETH_P_IPV6);
246 case SEG6_IPTUN_MODE_L2ENCAP:
247 if (!skb_mac_header_was_set(skb))
250 if (pskb_expand_head(skb, skb->mac_len, 0, GFP_ATOMIC) < 0)
253 skb_mac_header_rebuild(skb);
254 skb_push(skb, skb->mac_len);
256 err = seg6_do_srh_encap(skb, tinfo->srh, NEXTHDR_NONE);
260 skb->protocol = htons(ETH_P_IPV6);
264 ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
265 skb_set_transport_header(skb, sizeof(struct ipv6hdr));
270 static int seg6_input(struct sk_buff *skb)
272 struct dst_entry *orig_dst = skb_dst(skb);
273 struct dst_entry *dst = NULL;
274 struct seg6_lwt *slwt;
277 err = seg6_do_srh(skb);
283 slwt = seg6_lwt_lwtunnel(orig_dst->lwtstate);
286 dst = dst_cache_get(&slwt->cache);
292 ip6_route_input(skb);
296 dst_cache_set_ip6(&slwt->cache, dst,
297 &ipv6_hdr(skb)->saddr);
301 skb_dst_set(skb, dst);
304 err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev));
308 return dst_input(skb);
311 static int seg6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
313 struct dst_entry *orig_dst = skb_dst(skb);
314 struct dst_entry *dst = NULL;
315 struct seg6_lwt *slwt;
318 err = seg6_do_srh(skb);
322 slwt = seg6_lwt_lwtunnel(orig_dst->lwtstate);
325 dst = dst_cache_get(&slwt->cache);
328 if (unlikely(!dst)) {
329 struct ipv6hdr *hdr = ipv6_hdr(skb);
332 memset(&fl6, 0, sizeof(fl6));
333 fl6.daddr = hdr->daddr;
334 fl6.saddr = hdr->saddr;
335 fl6.flowlabel = ip6_flowinfo(hdr);
336 fl6.flowi6_mark = skb->mark;
337 fl6.flowi6_proto = hdr->nexthdr;
339 dst = ip6_route_output(net, NULL, &fl6);
347 dst_cache_set_ip6(&slwt->cache, dst, &fl6.saddr);
352 skb_dst_set(skb, dst);
354 err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev));
358 return dst_output(net, sk, skb);
364 static int seg6_build_state(struct nlattr *nla,
365 unsigned int family, const void *cfg,
366 struct lwtunnel_state **ts,
367 struct netlink_ext_ack *extack)
369 struct nlattr *tb[SEG6_IPTUNNEL_MAX + 1];
370 struct seg6_iptunnel_encap *tuninfo;
371 struct lwtunnel_state *newts;
372 int tuninfo_len, min_size;
373 struct seg6_lwt *slwt;
376 if (family != AF_INET && family != AF_INET6)
379 err = nla_parse_nested(tb, SEG6_IPTUNNEL_MAX, nla,
380 seg6_iptunnel_policy, extack);
385 if (!tb[SEG6_IPTUNNEL_SRH])
388 tuninfo = nla_data(tb[SEG6_IPTUNNEL_SRH]);
389 tuninfo_len = nla_len(tb[SEG6_IPTUNNEL_SRH]);
391 /* tuninfo must contain at least the iptunnel encap structure,
392 * the SRH and one segment
394 min_size = sizeof(*tuninfo) + sizeof(struct ipv6_sr_hdr) +
395 sizeof(struct in6_addr);
396 if (tuninfo_len < min_size)
399 switch (tuninfo->mode) {
400 case SEG6_IPTUN_MODE_INLINE:
401 if (family != AF_INET6)
405 case SEG6_IPTUN_MODE_ENCAP:
407 case SEG6_IPTUN_MODE_L2ENCAP:
413 /* verify that SRH is consistent */
414 if (!seg6_validate_srh(tuninfo->srh, tuninfo_len - sizeof(*tuninfo)))
417 newts = lwtunnel_state_alloc(tuninfo_len + sizeof(*slwt));
421 slwt = seg6_lwt_lwtunnel(newts);
423 err = dst_cache_init(&slwt->cache, GFP_ATOMIC);
429 memcpy(&slwt->tuninfo, tuninfo, tuninfo_len);
431 newts->type = LWTUNNEL_ENCAP_SEG6;
432 newts->flags |= LWTUNNEL_STATE_INPUT_REDIRECT;
434 if (tuninfo->mode != SEG6_IPTUN_MODE_L2ENCAP)
435 newts->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT;
437 newts->headroom = seg6_lwt_headroom(tuninfo);
444 static void seg6_destroy_state(struct lwtunnel_state *lwt)
446 dst_cache_destroy(&seg6_lwt_lwtunnel(lwt)->cache);
449 static int seg6_fill_encap_info(struct sk_buff *skb,
450 struct lwtunnel_state *lwtstate)
452 struct seg6_iptunnel_encap *tuninfo = seg6_encap_lwtunnel(lwtstate);
454 if (nla_put_srh(skb, SEG6_IPTUNNEL_SRH, tuninfo))
460 static int seg6_encap_nlsize(struct lwtunnel_state *lwtstate)
462 struct seg6_iptunnel_encap *tuninfo = seg6_encap_lwtunnel(lwtstate);
464 return nla_total_size(SEG6_IPTUN_ENCAP_SIZE(tuninfo));
467 static int seg6_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b)
469 struct seg6_iptunnel_encap *a_hdr = seg6_encap_lwtunnel(a);
470 struct seg6_iptunnel_encap *b_hdr = seg6_encap_lwtunnel(b);
471 int len = SEG6_IPTUN_ENCAP_SIZE(a_hdr);
473 if (len != SEG6_IPTUN_ENCAP_SIZE(b_hdr))
476 return memcmp(a_hdr, b_hdr, len);
479 static const struct lwtunnel_encap_ops seg6_iptun_ops = {
480 .build_state = seg6_build_state,
481 .destroy_state = seg6_destroy_state,
482 .output = seg6_output,
484 .fill_encap = seg6_fill_encap_info,
485 .get_encap_size = seg6_encap_nlsize,
486 .cmp_encap = seg6_encap_cmp,
487 .owner = THIS_MODULE,
490 int __init seg6_iptunnel_init(void)
492 return lwtunnel_encap_add_ops(&seg6_iptun_ops, LWTUNNEL_ENCAP_SEG6);
495 void seg6_iptunnel_exit(void)
497 lwtunnel_encap_del_ops(&seg6_iptun_ops, LWTUNNEL_ENCAP_SEG6);