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>

1 files changed, 28 insertions, 42 deletions

diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 9d5f6340af13..74909bac8817 100644
--- 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);