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 /* Compute flowlabel for outer IPv6 header */
95 static __be32 seg6_make_flowlabel(struct net *net, struct sk_buff *skb,
96 struct ipv6hdr *inner_hdr)
98 int do_flowlabel = net->ipv6.sysctl.seg6_flowlabel;
102 if (do_flowlabel > 0) {
103 hash = skb_get_hash(skb);
104 hash = rol32(hash, 16);
105 flowlabel = (__force __be32)hash & IPV6_FLOWLABEL_MASK;
106 } else if (!do_flowlabel && skb->protocol == htons(ETH_P_IPV6)) {
107 flowlabel = ip6_flowlabel(inner_hdr);
112 /* encapsulate an IPv6 packet within an outer IPv6 header with a given SRH */
113 int seg6_do_srh_encap(struct sk_buff *skb, struct ipv6_sr_hdr *osrh, int proto)
115 struct dst_entry *dst = skb_dst(skb);
116 struct net *net = dev_net(dst->dev);
117 struct ipv6hdr *hdr, *inner_hdr;
118 struct ipv6_sr_hdr *isrh;
119 int hdrlen, tot_len, err;
122 hdrlen = (osrh->hdrlen + 1) << 3;
123 tot_len = hdrlen + sizeof(*hdr);
125 err = skb_cow_head(skb, tot_len + skb->mac_len);
129 inner_hdr = ipv6_hdr(skb);
130 flowlabel = seg6_make_flowlabel(net, skb, inner_hdr);
132 skb_push(skb, tot_len);
133 skb_reset_network_header(skb);
134 skb_mac_header_rebuild(skb);
137 /* inherit tc, flowlabel and hlim
138 * hlim will be decremented in ip6_forward() afterwards and
139 * decapsulation will overwrite inner hlim with outer hlim
142 if (skb->protocol == htons(ETH_P_IPV6)) {
143 ip6_flow_hdr(hdr, ip6_tclass(ip6_flowinfo(inner_hdr)),
145 hdr->hop_limit = inner_hdr->hop_limit;
147 ip6_flow_hdr(hdr, 0, flowlabel);
148 hdr->hop_limit = ip6_dst_hoplimit(skb_dst(skb));
150 memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
153 hdr->nexthdr = NEXTHDR_ROUTING;
155 isrh = (void *)hdr + sizeof(*hdr);
156 memcpy(isrh, osrh, hdrlen);
158 isrh->nexthdr = proto;
160 hdr->daddr = isrh->segments[isrh->first_segment];
161 set_tun_src(net, dst->dev, &hdr->daddr, &hdr->saddr);
163 #ifdef CONFIG_IPV6_SEG6_HMAC
164 if (sr_has_hmac(isrh)) {
165 err = seg6_push_hmac(net, &hdr->saddr, isrh);
171 skb_postpush_rcsum(skb, hdr, tot_len);
175 EXPORT_SYMBOL_GPL(seg6_do_srh_encap);
177 /* insert an SRH within an IPv6 packet, just after the IPv6 header */
178 int seg6_do_srh_inline(struct sk_buff *skb, struct ipv6_sr_hdr *osrh)
180 struct ipv6hdr *hdr, *oldhdr;
181 struct ipv6_sr_hdr *isrh;
184 hdrlen = (osrh->hdrlen + 1) << 3;
186 err = skb_cow_head(skb, hdrlen + skb->mac_len);
190 oldhdr = ipv6_hdr(skb);
192 skb_pull(skb, sizeof(struct ipv6hdr));
193 skb_postpull_rcsum(skb, skb_network_header(skb),
194 sizeof(struct ipv6hdr));
196 skb_push(skb, sizeof(struct ipv6hdr) + hdrlen);
197 skb_reset_network_header(skb);
198 skb_mac_header_rebuild(skb);
202 memmove(hdr, oldhdr, sizeof(*hdr));
204 isrh = (void *)hdr + sizeof(*hdr);
205 memcpy(isrh, osrh, hdrlen);
207 isrh->nexthdr = hdr->nexthdr;
208 hdr->nexthdr = NEXTHDR_ROUTING;
210 isrh->segments[0] = hdr->daddr;
211 hdr->daddr = isrh->segments[isrh->first_segment];
213 #ifdef CONFIG_IPV6_SEG6_HMAC
214 if (sr_has_hmac(isrh)) {
215 struct net *net = dev_net(skb_dst(skb)->dev);
217 err = seg6_push_hmac(net, &hdr->saddr, isrh);
223 skb_postpush_rcsum(skb, hdr, sizeof(struct ipv6hdr) + hdrlen);
227 EXPORT_SYMBOL_GPL(seg6_do_srh_inline);
229 static int seg6_do_srh(struct sk_buff *skb)
231 struct dst_entry *dst = skb_dst(skb);
232 struct seg6_iptunnel_encap *tinfo;
235 tinfo = seg6_encap_lwtunnel(dst->lwtstate);
237 switch (tinfo->mode) {
238 case SEG6_IPTUN_MODE_INLINE:
239 if (skb->protocol != htons(ETH_P_IPV6))
242 err = seg6_do_srh_inline(skb, tinfo->srh);
246 case SEG6_IPTUN_MODE_ENCAP:
247 err = iptunnel_handle_offloads(skb, SKB_GSO_IPXIP6);
251 if (skb->protocol == htons(ETH_P_IPV6))
252 proto = IPPROTO_IPV6;
253 else if (skb->protocol == htons(ETH_P_IP))
254 proto = IPPROTO_IPIP;
258 err = seg6_do_srh_encap(skb, tinfo->srh, proto);
262 skb_set_inner_transport_header(skb, skb_transport_offset(skb));
263 skb_set_inner_protocol(skb, skb->protocol);
264 skb->protocol = htons(ETH_P_IPV6);
266 case SEG6_IPTUN_MODE_L2ENCAP:
267 if (!skb_mac_header_was_set(skb))
270 if (pskb_expand_head(skb, skb->mac_len, 0, GFP_ATOMIC) < 0)
273 skb_mac_header_rebuild(skb);
274 skb_push(skb, skb->mac_len);
276 err = seg6_do_srh_encap(skb, tinfo->srh, NEXTHDR_NONE);
280 skb->protocol = htons(ETH_P_IPV6);
284 ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
285 skb_set_transport_header(skb, sizeof(struct ipv6hdr));
290 static int seg6_input(struct sk_buff *skb)
292 struct dst_entry *orig_dst = skb_dst(skb);
293 struct dst_entry *dst = NULL;
294 struct seg6_lwt *slwt;
297 err = seg6_do_srh(skb);
303 slwt = seg6_lwt_lwtunnel(orig_dst->lwtstate);
306 dst = dst_cache_get(&slwt->cache);
312 ip6_route_input(skb);
316 dst_cache_set_ip6(&slwt->cache, dst,
317 &ipv6_hdr(skb)->saddr);
321 skb_dst_set(skb, dst);
324 err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev));
328 return dst_input(skb);
331 static int seg6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
333 struct dst_entry *orig_dst = skb_dst(skb);
334 struct dst_entry *dst = NULL;
335 struct seg6_lwt *slwt;
338 err = seg6_do_srh(skb);
342 slwt = seg6_lwt_lwtunnel(orig_dst->lwtstate);
345 dst = dst_cache_get(&slwt->cache);
348 if (unlikely(!dst)) {
349 struct ipv6hdr *hdr = ipv6_hdr(skb);
352 memset(&fl6, 0, sizeof(fl6));
353 fl6.daddr = hdr->daddr;
354 fl6.saddr = hdr->saddr;
355 fl6.flowlabel = ip6_flowinfo(hdr);
356 fl6.flowi6_mark = skb->mark;
357 fl6.flowi6_proto = hdr->nexthdr;
359 dst = ip6_route_output(net, NULL, &fl6);
367 dst_cache_set_ip6(&slwt->cache, dst, &fl6.saddr);
372 skb_dst_set(skb, dst);
374 err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev));
378 return dst_output(net, sk, skb);
384 static int seg6_build_state(struct nlattr *nla,
385 unsigned int family, const void *cfg,
386 struct lwtunnel_state **ts,
387 struct netlink_ext_ack *extack)
389 struct nlattr *tb[SEG6_IPTUNNEL_MAX + 1];
390 struct seg6_iptunnel_encap *tuninfo;
391 struct lwtunnel_state *newts;
392 int tuninfo_len, min_size;
393 struct seg6_lwt *slwt;
396 if (family != AF_INET && family != AF_INET6)
399 err = nla_parse_nested(tb, SEG6_IPTUNNEL_MAX, nla,
400 seg6_iptunnel_policy, extack);
405 if (!tb[SEG6_IPTUNNEL_SRH])
408 tuninfo = nla_data(tb[SEG6_IPTUNNEL_SRH]);
409 tuninfo_len = nla_len(tb[SEG6_IPTUNNEL_SRH]);
411 /* tuninfo must contain at least the iptunnel encap structure,
412 * the SRH and one segment
414 min_size = sizeof(*tuninfo) + sizeof(struct ipv6_sr_hdr) +
415 sizeof(struct in6_addr);
416 if (tuninfo_len < min_size)
419 switch (tuninfo->mode) {
420 case SEG6_IPTUN_MODE_INLINE:
421 if (family != AF_INET6)
425 case SEG6_IPTUN_MODE_ENCAP:
427 case SEG6_IPTUN_MODE_L2ENCAP:
433 /* verify that SRH is consistent */
434 if (!seg6_validate_srh(tuninfo->srh, tuninfo_len - sizeof(*tuninfo)))
437 newts = lwtunnel_state_alloc(tuninfo_len + sizeof(*slwt));
441 slwt = seg6_lwt_lwtunnel(newts);
443 err = dst_cache_init(&slwt->cache, GFP_ATOMIC);
449 memcpy(&slwt->tuninfo, tuninfo, tuninfo_len);
451 newts->type = LWTUNNEL_ENCAP_SEG6;
452 newts->flags |= LWTUNNEL_STATE_INPUT_REDIRECT;
454 if (tuninfo->mode != SEG6_IPTUN_MODE_L2ENCAP)
455 newts->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT;
457 newts->headroom = seg6_lwt_headroom(tuninfo);
464 static void seg6_destroy_state(struct lwtunnel_state *lwt)
466 dst_cache_destroy(&seg6_lwt_lwtunnel(lwt)->cache);
469 static int seg6_fill_encap_info(struct sk_buff *skb,
470 struct lwtunnel_state *lwtstate)
472 struct seg6_iptunnel_encap *tuninfo = seg6_encap_lwtunnel(lwtstate);
474 if (nla_put_srh(skb, SEG6_IPTUNNEL_SRH, tuninfo))
480 static int seg6_encap_nlsize(struct lwtunnel_state *lwtstate)
482 struct seg6_iptunnel_encap *tuninfo = seg6_encap_lwtunnel(lwtstate);
484 return nla_total_size(SEG6_IPTUN_ENCAP_SIZE(tuninfo));
487 static int seg6_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b)
489 struct seg6_iptunnel_encap *a_hdr = seg6_encap_lwtunnel(a);
490 struct seg6_iptunnel_encap *b_hdr = seg6_encap_lwtunnel(b);
491 int len = SEG6_IPTUN_ENCAP_SIZE(a_hdr);
493 if (len != SEG6_IPTUN_ENCAP_SIZE(b_hdr))
496 return memcmp(a_hdr, b_hdr, len);
499 static const struct lwtunnel_encap_ops seg6_iptun_ops = {
500 .build_state = seg6_build_state,
501 .destroy_state = seg6_destroy_state,
502 .output = seg6_output,
504 .fill_encap = seg6_fill_encap_info,
505 .get_encap_size = seg6_encap_nlsize,
506 .cmp_encap = seg6_encap_cmp,
507 .owner = THIS_MODULE,
510 int __init seg6_iptunnel_init(void)
512 return lwtunnel_encap_add_ops(&seg6_iptun_ops, LWTUNNEL_ENCAP_SEG6);
515 void seg6_iptunnel_exit(void)
517 lwtunnel_encap_del_ops(&seg6_iptun_ops, LWTUNNEL_ENCAP_SEG6);