1 // SPDX-License-Identifier: GPL-2.0-only
4 * (C) 2020 Alexander Aring <alex.aring@gmail.com>
7 #include <linux/rpl_iptunnel.h>
9 #include <net/dst_cache.h>
10 #include <net/ip6_route.h>
11 #include <net/lwtunnel.h>
15 struct rpl_iptunnel_encap {
16 struct ipv6_rpl_sr_hdr srh[0];
20 struct dst_cache cache;
21 struct rpl_iptunnel_encap tuninfo;
24 static inline struct rpl_lwt *rpl_lwt_lwtunnel(struct lwtunnel_state *lwt)
26 return (struct rpl_lwt *)lwt->data;
29 static inline struct rpl_iptunnel_encap *
30 rpl_encap_lwtunnel(struct lwtunnel_state *lwt)
32 return &rpl_lwt_lwtunnel(lwt)->tuninfo;
35 static const struct nla_policy rpl_iptunnel_policy[RPL_IPTUNNEL_MAX + 1] = {
36 [RPL_IPTUNNEL_SRH] = { .type = NLA_BINARY },
39 static bool rpl_validate_srh(struct net *net, struct ipv6_rpl_sr_hdr *srh,
44 if ((srh->hdrlen << 3) != seglen)
47 /* check at least one segment and seglen fit with segments_left */
48 if (!srh->segments_left ||
49 (srh->segments_left * sizeof(struct in6_addr)) != seglen)
52 if (srh->cmpri || srh->cmpre)
55 err = ipv6_chk_rpl_srh_loop(net, srh->rpl_segaddr,
60 if (ipv6_addr_type(&srh->rpl_segaddr[srh->segments_left - 1]) &
67 static int rpl_build_state(struct net *net, struct nlattr *nla,
68 unsigned int family, const void *cfg,
69 struct lwtunnel_state **ts,
70 struct netlink_ext_ack *extack)
72 struct nlattr *tb[RPL_IPTUNNEL_MAX + 1];
73 struct lwtunnel_state *newts;
74 struct ipv6_rpl_sr_hdr *srh;
78 if (family != AF_INET6)
81 err = nla_parse_nested(tb, RPL_IPTUNNEL_MAX, nla,
82 rpl_iptunnel_policy, extack);
86 if (!tb[RPL_IPTUNNEL_SRH])
89 srh = nla_data(tb[RPL_IPTUNNEL_SRH]);
90 srh_len = nla_len(tb[RPL_IPTUNNEL_SRH]);
92 if (srh_len < sizeof(*srh))
95 /* verify that SRH is consistent */
96 if (!rpl_validate_srh(net, srh, srh_len - sizeof(*srh)))
99 newts = lwtunnel_state_alloc(srh_len + sizeof(*rlwt));
103 rlwt = rpl_lwt_lwtunnel(newts);
105 err = dst_cache_init(&rlwt->cache, GFP_ATOMIC);
111 memcpy(&rlwt->tuninfo.srh, srh, srh_len);
113 newts->type = LWTUNNEL_ENCAP_RPL;
114 newts->flags |= LWTUNNEL_STATE_INPUT_REDIRECT;
115 newts->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT;
122 static void rpl_destroy_state(struct lwtunnel_state *lwt)
124 dst_cache_destroy(&rpl_lwt_lwtunnel(lwt)->cache);
127 static int rpl_do_srh_inline(struct sk_buff *skb, const struct rpl_lwt *rlwt,
128 const struct ipv6_rpl_sr_hdr *srh)
130 struct ipv6_rpl_sr_hdr *isrh, *csrh;
131 const struct ipv6hdr *oldhdr;
137 oldhdr = ipv6_hdr(skb);
139 buf = kzalloc(ipv6_rpl_srh_alloc_size(srh->segments_left - 1) * 2,
144 isrh = (struct ipv6_rpl_sr_hdr *)buf;
145 csrh = (struct ipv6_rpl_sr_hdr *)(buf + ((srh->hdrlen + 1) << 3));
147 memcpy(isrh, srh, sizeof(*isrh));
148 memcpy(isrh->rpl_segaddr, &srh->rpl_segaddr[1],
149 (srh->segments_left - 1) * 16);
150 isrh->rpl_segaddr[srh->segments_left - 1] = oldhdr->daddr;
152 ipv6_rpl_srh_compress(csrh, isrh, &srh->rpl_segaddr[0],
153 isrh->segments_left - 1);
155 hdrlen = ((csrh->hdrlen + 1) << 3);
157 err = skb_cow_head(skb, hdrlen + skb->mac_len);
163 skb_pull(skb, sizeof(struct ipv6hdr));
164 skb_postpull_rcsum(skb, skb_network_header(skb),
165 sizeof(struct ipv6hdr));
167 skb_push(skb, sizeof(struct ipv6hdr) + hdrlen);
168 skb_reset_network_header(skb);
169 skb_mac_header_rebuild(skb);
172 memmove(hdr, oldhdr, sizeof(*hdr));
173 isrh = (void *)hdr + sizeof(*hdr);
174 memcpy(isrh, csrh, hdrlen);
176 isrh->nexthdr = hdr->nexthdr;
177 hdr->nexthdr = NEXTHDR_ROUTING;
178 hdr->daddr = srh->rpl_segaddr[0];
180 ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
181 skb_set_transport_header(skb, sizeof(struct ipv6hdr));
183 skb_postpush_rcsum(skb, hdr, sizeof(struct ipv6hdr) + hdrlen);
190 static int rpl_do_srh(struct sk_buff *skb, const struct rpl_lwt *rlwt)
192 struct dst_entry *dst = skb_dst(skb);
193 struct rpl_iptunnel_encap *tinfo;
196 if (skb->protocol != htons(ETH_P_IPV6))
199 tinfo = rpl_encap_lwtunnel(dst->lwtstate);
201 err = rpl_do_srh_inline(skb, rlwt, tinfo->srh);
208 static int rpl_output(struct net *net, struct sock *sk, struct sk_buff *skb)
210 struct dst_entry *orig_dst = skb_dst(skb);
211 struct dst_entry *dst = NULL;
212 struct rpl_lwt *rlwt;
215 rlwt = rpl_lwt_lwtunnel(orig_dst->lwtstate);
217 err = rpl_do_srh(skb, rlwt);
222 dst = dst_cache_get(&rlwt->cache);
225 if (unlikely(!dst)) {
226 struct ipv6hdr *hdr = ipv6_hdr(skb);
229 memset(&fl6, 0, sizeof(fl6));
230 fl6.daddr = hdr->daddr;
231 fl6.saddr = hdr->saddr;
232 fl6.flowlabel = ip6_flowinfo(hdr);
233 fl6.flowi6_mark = skb->mark;
234 fl6.flowi6_proto = hdr->nexthdr;
236 dst = ip6_route_output(net, NULL, &fl6);
244 dst_cache_set_ip6(&rlwt->cache, dst, &fl6.saddr);
249 skb_dst_set(skb, dst);
251 err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev));
255 return dst_output(net, sk, skb);
262 static int rpl_input(struct sk_buff *skb)
264 struct dst_entry *orig_dst = skb_dst(skb);
265 struct dst_entry *dst = NULL;
266 struct rpl_lwt *rlwt;
269 rlwt = rpl_lwt_lwtunnel(orig_dst->lwtstate);
271 err = rpl_do_srh(skb, rlwt);
278 dst = dst_cache_get(&rlwt->cache);
284 ip6_route_input(skb);
288 dst_cache_set_ip6(&rlwt->cache, dst,
289 &ipv6_hdr(skb)->saddr);
293 skb_dst_set(skb, dst);
296 err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev));
300 return dst_input(skb);
303 static int nla_put_rpl_srh(struct sk_buff *skb, int attrtype,
304 struct rpl_iptunnel_encap *tuninfo)
306 struct rpl_iptunnel_encap *data;
310 len = RPL_IPTUNNEL_SRH_SIZE(tuninfo->srh);
312 nla = nla_reserve(skb, attrtype, len);
316 data = nla_data(nla);
317 memcpy(data, tuninfo->srh, len);
322 static int rpl_fill_encap_info(struct sk_buff *skb,
323 struct lwtunnel_state *lwtstate)
325 struct rpl_iptunnel_encap *tuninfo = rpl_encap_lwtunnel(lwtstate);
327 if (nla_put_rpl_srh(skb, RPL_IPTUNNEL_SRH, tuninfo))
333 static int rpl_encap_nlsize(struct lwtunnel_state *lwtstate)
335 struct rpl_iptunnel_encap *tuninfo = rpl_encap_lwtunnel(lwtstate);
337 return nla_total_size(RPL_IPTUNNEL_SRH_SIZE(tuninfo->srh));
340 static int rpl_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b)
342 struct rpl_iptunnel_encap *a_hdr = rpl_encap_lwtunnel(a);
343 struct rpl_iptunnel_encap *b_hdr = rpl_encap_lwtunnel(b);
344 int len = RPL_IPTUNNEL_SRH_SIZE(a_hdr->srh);
346 if (len != RPL_IPTUNNEL_SRH_SIZE(b_hdr->srh))
349 return memcmp(a_hdr, b_hdr, len);
352 static const struct lwtunnel_encap_ops rpl_ops = {
353 .build_state = rpl_build_state,
354 .destroy_state = rpl_destroy_state,
355 .output = rpl_output,
357 .fill_encap = rpl_fill_encap_info,
358 .get_encap_size = rpl_encap_nlsize,
359 .cmp_encap = rpl_encap_cmp,
360 .owner = THIS_MODULE,
363 int __init rpl_init(void)
367 err = lwtunnel_encap_add_ops(&rpl_ops, LWTUNNEL_ENCAP_RPL);
371 pr_info("RPL Segment Routing with IPv6\n");
381 lwtunnel_encap_del_ops(&rpl_ops, LWTUNNEL_ENCAP_RPL);