netns: ipmr: enable namespace support in ipv4 multicast routing code

This last patch makes the appropriate changes to use and propagate the
network namespace where needed in IPv4 multicast routing code.

This consists mainly in replacing all the remaining init_net occurences
with current netns pointer retrieved from sockets, net devices or
mfc_caches depending on the routines' contexts.

Some routines receive a new 'struct net' parameter to propagate the current
netns:
* vif_add/vif_delete
* ipmr_new_tunnel
* mroute_clean_tables
* ipmr_cache_find
* ipmr_cache_report
* ipmr_cache_unresolved
* ipmr_mfc_add/ipmr_mfc_delete
* ipmr_get_route
* rt_fill_info (in route.c)
Signed-off-by: NBenjamin Thery <benjamin.thery@bull.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/linux/mroute.h

@@ -256,7 +256,8 @@ void mfc_net_set(struct mfc_cache *mfc, struct net *net)
 
 #ifdef __KERNEL__
 struct rtmsg;
-extern int ipmr_get_route(struct sk_buff *skb, struct rtmsg *rtm, int nowait);
+extern int ipmr_get_route(struct net *net, struct sk_buff *skb,
+			  struct rtmsg *rtm, int nowait);
 #endif
 
 #endif

net/ipv4/route.c

@@ -2779,7 +2779,8 @@ int ip_route_output_key(struct net *net, struct rtable **rp, struct flowi *flp)
 	return ip_route_output_flow(net, rp, flp, NULL, 0);
 }
 
-static int rt_fill_info(struct sk_buff *skb, u32 pid, u32 seq, int event,
+static int rt_fill_info(struct net *net,
+			struct sk_buff *skb, u32 pid, u32 seq, int event,
 			int nowait, unsigned int flags)
 {
 	struct rtable *rt = skb->rtable;
@@ -2844,8 +2845,8 @@ static int rt_fill_info(struct sk_buff *skb, u32 pid, u32 seq, int event,
 		__be32 dst = rt->rt_dst;
 
 		if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) &&
-		    IPV4_DEVCONF_ALL(&init_net, MC_FORWARDING)) {
-			int err = ipmr_get_route(skb, r, nowait);
+		    IPV4_DEVCONF_ALL(net, MC_FORWARDING)) {
+			int err = ipmr_get_route(net, skb, r, nowait);
 			if (err <= 0) {
 				if (!nowait) {
 					if (err == 0)
@@ -2950,7 +2951,7 @@ static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr* nlh, void
 	if (rtm->rtm_flags & RTM_F_NOTIFY)
 		rt->rt_flags |= RTCF_NOTIFY;
 
-	err = rt_fill_info(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
+	err = rt_fill_info(net, skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
 			   RTM_NEWROUTE, 0, 0);
 	if (err <= 0)
 		goto errout_free;
@@ -2988,7 +2989,7 @@ int ip_rt_dump(struct sk_buff *skb,  struct netlink_callback *cb)
 			if (rt_is_expired(rt))
 				continue;
 			skb->dst = dst_clone(&rt->u.dst);
-			if (rt_fill_info(skb, NETLINK_CB(cb->skb).pid,
+			if (rt_fill_info(net, skb, NETLINK_CB(cb->skb).pid,
 					 cb->nlh->nlmsg_seq, RTM_NEWROUTE,
 					 1, NLM_F_MULTI) <= 0) {
 				dst_release(xchg(&skb->dst, NULL));