[IPV6] MROUTE: Support multicast forwarding.

Based on ancient patch by Mickael Hoerdt
<hoerdt@clarinet.u-strasbg.fr>, which is available at
<http://www-r2.u-strasbg.fr/~hoerdt/dev/linux_ipv6_mforwarding/patch-linux-ipv6-mforwarding-0.1a>.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>

1 files changed, 23 insertions, 7 deletions

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index cd82b6db35ff..3c314d5f46c6 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -36,6 +36,7 @@
 #include <linux/route.h>
 #include <linux/netdevice.h>
 #include <linux/in6.h>
+#include <linux/mroute6.h>
 #include <linux/init.h>
 #include <linux/if_arp.h>
 #include <linux/proc_fs.h>
@@ -2106,7 +2107,7 @@ static inline size_t rt6_nlmsg_size(void)
 static int rt6_fill_node(struct sk_buff *skb, struct rt6_info *rt,
                          struct in6_addr *dst, struct in6_addr *src,
                          int iif, int type, u32 pid, u32 seq,
-                         int prefix, unsigned int flags)
+                         int prefix, int nowait, unsigned int flags)
 {
         struct rtmsg *rtm;
         struct nlmsghdr *nlh;
@@ -2166,9 +2167,24 @@ static int rt6_fill_node(struct sk_buff *skb, struct rt6_info *rt,
         } else if (rtm->rtm_src_len)
                 NLA_PUT(skb, RTA_SRC, 16, &rt->rt6i_src.addr);
 #endif
-        if (iif)
-                NLA_PUT_U32(skb, RTA_IIF, iif);
-        else if (dst) {
+        if (iif) {
+#ifdef CONFIG_IPV6_MROUTE
+                if (ipv6_addr_is_multicast(&rt->rt6i_dst.addr)) {
+                        int err = ip6mr_get_route(skb, rtm, nowait);
+                        if (err <= 0) {
+                                if (!nowait) {
+                                        if (err == 0)
+                                                return 0;
+                                        goto nla_put_failure;
+                                } else {
+                                        if (err == -EMSGSIZE)
+                                                goto nla_put_failure;
+                                }
+                        }
+                } else
+#endif
+                        NLA_PUT_U32(skb, RTA_IIF, iif);
+        } else if (dst) {
                 struct in6_addr saddr_buf;
                 if (ipv6_dev_get_saddr(ip6_dst_idev(&rt->u.dst)->dev,
                                        dst, 0, &saddr_buf) == 0)
@@ -2211,7 +2227,7 @@ int rt6_dump_route(struct rt6_info *rt, void *p_arg)
 
         return rt6_fill_node(arg->skb, rt, NULL, NULL, 0, RTM_NEWROUTE,
                      NETLINK_CB(arg->cb->skb).pid, arg->cb->nlh->nlmsg_seq,
-                     prefix, NLM_F_MULTI);
+                     prefix, 0, NLM_F_MULTI);
 }
 
 static int inet6_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr* nlh, void *arg)
@@ -2277,7 +2293,7 @@ static int inet6_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr* nlh, void
 
         err = rt6_fill_node(skb, rt, &fl.fl6_dst, &fl.fl6_src, iif,
                             RTM_NEWROUTE, NETLINK_CB(in_skb).pid,
-                            nlh->nlmsg_seq, 0, 0);
+                            nlh->nlmsg_seq, 0, 0, 0);
         if (err < 0) {
                 kfree_skb(skb);
                 goto errout;
@@ -2303,7 +2319,7 @@ void inet6_rt_notify(int event, struct rt6_info *rt, struct nl_info *info)
                 goto errout;
 
         err = rt6_fill_node(skb, rt, NULL, NULL, 0,
-                                event, info->pid, seq, 0, 0);
+                                event, info->pid, seq, 0, 0, 0);
         if (err < 0) {
                 /* -EMSGSIZE implies BUG in rt6_nlmsg_size() */
                 WARN_ON(err == -EMSGSIZE);