This patch adds support for per-socket SRH injection with the setsockopt
system call through the IPPROTO_IPV6, IPV6_RTHDR options.
The SRH is pushed through the ipv6_push_nfrag_opts function.

Signed-off-by: David Lebrun <david.leb...@uclouvain.be>
---
 net/ipv6/exthdrs.c       | 79 +++++++++++++++++++++++++++++++++++++++++++++---
 net/ipv6/ipv6_sockglue.c |  2 ++
 2 files changed, 77 insertions(+), 4 deletions(-)

diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c
index 1690ace..e7b46f8 100644
--- a/net/ipv6/exthdrs.c
+++ b/net/ipv6/exthdrs.c
@@ -854,9 +854,9 @@ int ipv6_parse_hopopts(struct sk_buff *skb)
  *     for headers.
  */
 
-static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto,
-                           struct ipv6_rt_hdr *opt,
-                           struct in6_addr **addr_p, struct in6_addr *saddr)
+static void ipv6_push_rthdr0(struct sk_buff *skb, u8 *proto,
+                            struct ipv6_rt_hdr *opt,
+                            struct in6_addr **addr_p, struct in6_addr *saddr)
 {
        struct rt0_hdr *phdr, *ihdr;
        int hops;
@@ -879,6 +879,62 @@ static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto,
        *proto = NEXTHDR_ROUTING;
 }
 
+static void ipv6_push_rthdr4(struct sk_buff *skb, u8 *proto,
+                            struct ipv6_rt_hdr *opt,
+                            struct in6_addr **addr_p, struct in6_addr *saddr)
+{
+       struct ipv6_sr_hdr *sr_phdr, *sr_ihdr;
+       int plen, hops;
+
+       sr_ihdr = (struct ipv6_sr_hdr *)opt;
+       plen = (sr_ihdr->hdrlen + 1) << 3;
+
+       sr_phdr = (struct ipv6_sr_hdr *)skb_push(skb, plen);
+       memcpy(sr_phdr, sr_ihdr, sizeof(struct ipv6_sr_hdr));
+
+       hops = sr_ihdr->first_segment + 1;
+       memcpy(sr_phdr->segments + 1, sr_ihdr->segments + 1,
+              (hops - 1) * sizeof(struct in6_addr));
+
+       sr_phdr->segments[0] = **addr_p;
+       *addr_p = &sr_ihdr->segments[hops - 1];
+
+#ifdef CONFIG_IPV6_SEG6_HMAC
+       if (sr_has_hmac(sr_phdr)) {
+               struct net *net = NULL;
+
+               if (skb->dev)
+                       net = dev_net(skb->dev);
+               else if (skb->sk)
+                       net = sock_net(skb->sk);
+
+               WARN_ON(!net);
+
+               if (net)
+                       seg6_push_hmac(net, saddr, sr_phdr);
+       }
+#endif
+
+       sr_phdr->nexthdr = *proto;
+       *proto = NEXTHDR_ROUTING;
+}
+
+static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto,
+                           struct ipv6_rt_hdr *opt,
+                           struct in6_addr **addr_p, struct in6_addr *saddr)
+{
+       switch (opt->type) {
+       case IPV6_SRCRT_TYPE_0:
+               ipv6_push_rthdr0(skb, proto, opt, addr_p, saddr);
+               break;
+       case IPV6_SRCRT_TYPE_4:
+               ipv6_push_rthdr4(skb, proto, opt, addr_p, saddr);
+               break;
+       default:
+               break;
+       }
+}
+
 static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct 
ipv6_opt_hdr *opt)
 {
        struct ipv6_opt_hdr *h = (struct ipv6_opt_hdr *)skb_push(skb, 
ipv6_optlen(opt));
@@ -1120,7 +1176,22 @@ struct in6_addr *fl6_update_dst(struct flowi6 *fl6,
                return NULL;
 
        *orig = fl6->daddr;
-       fl6->daddr = *((struct rt0_hdr *)opt->srcrt)->addr;
+
+       switch (opt->srcrt->type) {
+       case IPV6_SRCRT_TYPE_0:
+               fl6->daddr = *((struct rt0_hdr *)opt->srcrt)->addr;
+               break;
+       case IPV6_SRCRT_TYPE_4:
+       {
+               struct ipv6_sr_hdr *srh = (struct ipv6_sr_hdr *)opt->srcrt;
+
+               fl6->daddr = srh->segments[srh->first_segment];
+               break;
+       }
+       default:
+               return NULL;
+       }
+
        return orig;
 }
 EXPORT_SYMBOL_GPL(fl6_update_dst);
diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c
index 6c12678..780fd6b 100644
--- a/net/ipv6/ipv6_sockglue.c
+++ b/net/ipv6/ipv6_sockglue.c
@@ -430,6 +430,8 @@ static int do_ipv6_setsockopt(struct sock *sk, int level, 
int optname,
 
                                break;
 #endif
+                       case IPV6_SRCRT_TYPE_4:
+                               break;
                        default:
                                goto sticky_done;
                        }
-- 
2.7.3

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