ipv4: Lookup multicast routes by rtable using helper.

Create a common helper for this operation, since we do
it identically in three spots.

Suggested by Eric Dumazet.

Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 9d5f6340af13fb6012abdde7bdd0c66c1fd4d45e..74909bac88171b076a6305a1a3a3bc4b7fc23ef9 100644 (file)
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -1793,6 +1793,24 @@ dont_forward:
        return 0;
 }
 
+static struct mr_table *ipmr_rt_fib_lookup(struct net *net, struct rtable *rt)
+{
+       struct flowi fl = {
+               .fl4_dst = rt->rt_key_dst,
+               .fl4_src = rt->rt_key_src,
+               .fl4_tos = rt->rt_tos,
+               .oif = rt->rt_oif,
+               .iif = rt->rt_iif,
+               .mark = rt->rt_mark,
+       };
+       struct mr_table *mrt;
+       int err;
+
+       err = ipmr_fib_lookup(net, &fl, &mrt);
+       if (err)
+               return ERR_PTR(err);
+       return mrt;
+}
 
 /*
  *     Multicast packets for forwarding arrive here
@@ -1805,7 +1823,6 @@ int ip_mr_input(struct sk_buff *skb)
        struct net *net = dev_net(skb->dev);
        int local = skb_rtable(skb)->rt_flags & RTCF_LOCAL;
        struct mr_table *mrt;
-       int err;
 
        /* Packet is looped back after forward, it should not be
         * forwarded second time, but still can be delivered locally.
@@ -1813,21 +1830,10 @@ int ip_mr_input(struct sk_buff *skb)
        if (IPCB(skb)->flags & IPSKB_FORWARDED)
                goto dont_forward;
 
-       {
-               struct rtable *rt = skb_rtable(skb);
-               struct flowi fl = {
-                       .fl4_dst = rt->rt_key_dst,
-                       .fl4_src = rt->rt_key_src,
-                       .fl4_tos = rt->rt_tos,
-                       .oif = rt->rt_oif,
-                       .iif = rt->rt_iif,
-                       .mark = rt->rt_mark,
-               };
-               err = ipmr_fib_lookup(net, &fl, &mrt);
-               if (err < 0) {
-                       kfree_skb(skb);
-                       return err;
-               }
+       mrt = ipmr_rt_fib_lookup(net, skb_rtable(skb));
+       if (IS_ERR(mrt)) {
+               kfree_skb(skb);
+               return PTR_ERR(mrt);
        }
        if (!local) {
                if (IPCB(skb)->opt.router_alert) {
@@ -1956,19 +1962,9 @@ int pim_rcv_v1(struct sk_buff *skb)
 
        pim = igmp_hdr(skb);
 
-       {
-               struct rtable *rt = skb_rtable(skb);
-               struct flowi fl = {
-                       .fl4_dst = rt->rt_key_dst,
-                       .fl4_src = rt->rt_key_src,
-                       .fl4_tos = rt->rt_tos,
-                       .oif = rt->rt_oif,
-                       .iif = rt->rt_iif,
-                       .mark = rt->rt_mark,
-               };
-               if (ipmr_fib_lookup(net, &fl, &mrt) < 0)
-                       goto drop;
-       }
+       mrt = ipmr_rt_fib_lookup(net, skb_rtable(skb));
+       if (IS_ERR(mrt))
+               goto drop;
        if (!mrt->mroute_do_pim ||
            pim->group != PIM_V1_VERSION || pim->code != PIM_V1_REGISTER)
                goto drop;
@@ -1998,19 +1994,9 @@ static int pim_rcv(struct sk_buff *skb)
             csum_fold(skb_checksum(skb, 0, skb->len, 0))))
                goto drop;
 
-       {
-               struct rtable *rt = skb_rtable(skb);
-               struct flowi fl = {
-                       .fl4_dst = rt->rt_key_dst,
-                       .fl4_src = rt->rt_key_src,
-                       .fl4_tos = rt->rt_tos,
-                       .oif = rt->rt_oif,
-                       .iif = rt->rt_iif,
-                       .mark = rt->rt_mark,
-               };
-               if (ipmr_fib_lookup(net, &fl, &mrt) < 0)
-                       goto drop;
-       }
+       mrt = ipmr_rt_fib_lookup(net, skb_rtable(skb));
+       if (IS_ERR(mrt))
+               goto drop;
        if (__pim_rcv(mrt, skb, sizeof(*pim))) {
 drop:
                kfree_skb(skb);