[IPV6]: ROUTE: Add experimental support for Route Information Option in RA (RFC4191).

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 166 insertions, 1 deletions

diff --git a/net/ipv6/Kconfig b/net/ipv6/Kconfig
index c456ead8a4a3..e6f83b6a2b76 100644
--- a/net/ipv6/Kconfig
+++ b/net/ipv6/Kconfig
@@ -49,6 +49,14 @@ config IPV6_ROUTER_PREF
 
           If unsure, say N.
 
+config IPV6_ROUTE_INFO
+        bool "IPv6: Route Information (RFC 4191) support (EXPERIMENTAL)"
+        depends on IPV6_ROUTER_PREF && EXPERIMENTAL
+        ---help---
+          This is experimental support of Route Information.
+
+          If unsure, say N.
+
 config INET6_AH
         tristate "IPv6: AH transformation"
         depends on IPV6
diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index f4462ee33024..1f6256909674 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -156,7 +156,11 @@ struct neigh_table nd_tbl = {
 
 /* ND options */
 struct ndisc_options {
-        struct nd_opt_hdr *nd_opt_array[__ND_OPT_MAX];
+        struct nd_opt_hdr *nd_opt_array[__ND_OPT_ARRAY_MAX];
+#ifdef CONFIG_IPV6_ROUTE_INFO
+        struct nd_opt_hdr *nd_opts_ri;
+        struct nd_opt_hdr *nd_opts_ri_end;
+#endif
 };
 
 #define nd_opts_src_lladdr      nd_opt_array[ND_OPT_SOURCE_LL_ADDR]
@@ -255,6 +259,13 @@ static struct ndisc_options *ndisc_parse_options(u8 *opt, int opt_len,
                         if (ndopts->nd_opt_array[nd_opt->nd_opt_type] == 0)
                                 ndopts->nd_opt_array[nd_opt->nd_opt_type] = nd_opt;
                         break;
+#ifdef CONFIG_IPV6_ROUTE_INFO
+                case ND_OPT_ROUTE_INFO:
+                        ndopts->nd_opts_ri_end = nd_opt;
+                        if (!ndopts->nd_opts_ri)
+                                ndopts->nd_opts_ri = nd_opt;
+                        break;
+#endif
                 default:
                         /*
                          * Unknown options must be silently ignored,
@@ -1202,6 +1213,18 @@ skip_defrtr:
                              NEIGH_UPDATE_F_ISROUTER);
         }
 
+#ifdef CONFIG_IPV6_ROUTE_INFO
+        if (ndopts.nd_opts_ri) {
+                struct nd_opt_hdr *p;
+                for (p = ndopts.nd_opts_ri;
+                     p;
+                     p = ndisc_next_option(p, ndopts.nd_opts_ri_end)) {
+                        rt6_route_rcv(skb->dev, (u8*)p, (p->nd_opt_len) << 3,
+                                      &skb->nh.ipv6h->saddr);
+                }
+        }
+#endif
+
         if (in6_dev->cnf.accept_ra_pinfo && ndopts.nd_opts_pi) {
                 struct nd_opt_hdr *p;
                 for (p = ndopts.nd_opts_pi;
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index c797b9bbb7d1..0f30ee3d94ea 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -98,6 +98,14 @@ static int		ip6_pkt_discard_out(struct sk_buff *skb);
 static void             ip6_link_failure(struct sk_buff *skb);
 static void             ip6_rt_update_pmtu(struct dst_entry *dst, u32 mtu);
 
+#ifdef CONFIG_IPV6_ROUTE_INFO
+static struct rt6_info *rt6_add_route_info(struct in6_addr *prefix, int prefixlen,
+                                           struct in6_addr *gwaddr, int ifindex,
+                                           unsigned pref);
+static struct rt6_info *rt6_get_route_info(struct in6_addr *prefix, int prefixlen,
+                                           struct in6_addr *gwaddr, int ifindex);
+#endif
+
 static struct dst_ops ip6_dst_ops = {
         .family                 =       AF_INET6,
         .protocol               =       __constant_htons(ETH_P_IPV6),
@@ -346,6 +354,84 @@ static struct rt6_info *rt6_select(struct rt6_info **head, int oif,
         return (match ? match : &ip6_null_entry);
 }
 
+#ifdef CONFIG_IPV6_ROUTE_INFO
+int rt6_route_rcv(struct net_device *dev, u8 *opt, int len,
+                  struct in6_addr *gwaddr)
+{
+        struct route_info *rinfo = (struct route_info *) opt;
+        struct in6_addr prefix_buf, *prefix;
+        unsigned int pref;
+        u32 lifetime;
+        struct rt6_info *rt;
+
+        if (len < sizeof(struct route_info)) {
+                return -EINVAL;
+        }
+
+        /* Sanity check for prefix_len and length */
+        if (rinfo->length > 3) {
+                return -EINVAL;
+        } else if (rinfo->prefix_len > 128) {
+                return -EINVAL;
+        } else if (rinfo->prefix_len > 64) {
+                if (rinfo->length < 2) {
+                        return -EINVAL;
+                }
+        } else if (rinfo->prefix_len > 0) {
+                if (rinfo->length < 1) {
+                        return -EINVAL;
+                }
+        }
+
+        pref = rinfo->route_pref;
+        if (pref == ICMPV6_ROUTER_PREF_INVALID)
+                pref = ICMPV6_ROUTER_PREF_MEDIUM;
+
+        lifetime = htonl(rinfo->lifetime);
+        if (lifetime == 0xffffffff) {
+                /* infinity */
+        } else if (lifetime > 0x7fffffff/HZ) {
+                /* Avoid arithmetic overflow */
+                lifetime = 0x7fffffff/HZ - 1;
+        }
+
+        if (rinfo->length == 3)
+                prefix = (struct in6_addr *)rinfo->prefix;
+        else {
+                /* this function is safe */
+                ipv6_addr_prefix(&prefix_buf,
+                                 (struct in6_addr *)rinfo->prefix,
+                                 rinfo->prefix_len);
+                prefix = &prefix_buf;
+        }
+
+        rt = rt6_get_route_info(prefix, rinfo->prefix_len, gwaddr, dev->ifindex);
+
+        if (rt && !lifetime) {
+                ip6_del_rt(rt, NULL, NULL, NULL);
+                rt = NULL;
+        }
+
+        if (!rt && lifetime)
+                rt = rt6_add_route_info(prefix, rinfo->prefix_len, gwaddr, dev->ifindex,
+                                        pref);
+        else if (rt)
+                rt->rt6i_flags = RTF_ROUTEINFO |
+                                 (rt->rt6i_flags & ~RTF_PREF_MASK) | RTF_PREF(pref);
+
+        if (rt) {
+                if (lifetime == 0xffffffff) {
+                        rt->rt6i_flags &= ~RTF_EXPIRES;
+                } else {
+                        rt->rt6i_expires = jiffies + HZ * lifetime;
+                        rt->rt6i_flags |= RTF_EXPIRES;
+                }
+                dst_release(&rt->u.dst);
+        }
+        return 0;
+}
+#endif
+
 struct rt6_info *rt6_lookup(struct in6_addr *daddr, struct in6_addr *saddr,
                             int oif, int strict)
 {
@@ -1277,6 +1363,54 @@ static struct rt6_info * ip6_rt_copy(struct rt6_info *ort)
         return rt;
 }
 
+#ifdef CONFIG_IPV6_ROUTE_INFO
+static struct rt6_info *rt6_get_route_info(struct in6_addr *prefix, int prefixlen,
+                                           struct in6_addr *gwaddr, int ifindex)
+{
+        struct fib6_node *fn;
+        struct rt6_info *rt = NULL;
+
+        write_lock_bh(&rt6_lock);
+        fn = fib6_locate(&ip6_routing_table, prefix ,prefixlen, NULL, 0);
+        if (!fn)
+                goto out;
+
+        for (rt = fn->leaf; rt; rt = rt->u.next) {
+                if (rt->rt6i_dev->ifindex != ifindex)
+                        continue;
+                if ((rt->rt6i_flags & (RTF_ROUTEINFO|RTF_GATEWAY)) != (RTF_ROUTEINFO|RTF_GATEWAY))
+                        continue;
+                if (!ipv6_addr_equal(&rt->rt6i_gateway, gwaddr))
+                        continue;
+                dst_hold(&rt->u.dst);
+                break;
+        }
+out:
+        write_unlock_bh(&rt6_lock);
+        return rt;
+}
+
+static struct rt6_info *rt6_add_route_info(struct in6_addr *prefix, int prefixlen,
+                                           struct in6_addr *gwaddr, int ifindex,
+                                           unsigned pref)
+{
+        struct in6_rtmsg rtmsg;
+
+        memset(&rtmsg, 0, sizeof(rtmsg));
+        rtmsg.rtmsg_type = RTMSG_NEWROUTE;
+        ipv6_addr_copy(&rtmsg.rtmsg_dst, prefix);
+        rtmsg.rtmsg_dst_len = prefixlen;
+        ipv6_addr_copy(&rtmsg.rtmsg_gateway, gwaddr);
+        rtmsg.rtmsg_metric = 1024;
+        rtmsg.rtmsg_flags = RTF_GATEWAY | RTF_ADDRCONF | RTF_ROUTEINFO | RTF_UP | RTF_PREF(pref);
+        rtmsg.rtmsg_ifindex = ifindex;
+
+        ip6_route_add(&rtmsg, NULL, NULL, NULL);
+
+        return rt6_get_route_info(prefix, prefixlen, gwaddr, ifindex);
+}
+#endif
+
 struct rt6_info *rt6_get_dflt_router(struct in6_addr *addr, struct net_device *dev)
 {       
         struct rt6_info *rt;