arp: correct return value of arp_rcv

Currently, arp_rcv() always return zero on a packet delivery upcall.

To make its behavior more compliant with the way this API should be
used, this patch changes this to let it return NET_RX_SUCCESS when the
packet is proper handled, and NET_RX_DROP otherwise.

v1->v2:
If sanity check is failed, call kfree_skb() instead of consume_skb(), then
return the correct return value.

Signed-off-by: Zhang Shengju <zhangshengju@cmss.chinamobile.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
index c102eb5..c34c754 100644 (file)
--- a/net/ipv4/arp.c
+++ b/net/ipv4/arp.c
@@ -665,7 +665,7 @@ static int arp_process(struct net *net, struct sock *sk, struct sk_buff *skb)
         */
 
        if (!in_dev)
-               goto out;
+               goto out_free_skb;
 
        arp = arp_hdr(skb);
 
@@ -673,7 +673,7 @@ static int arp_process(struct net *net, struct sock *sk, struct sk_buff *skb)
        default:
                if (arp->ar_pro != htons(ETH_P_IP) ||
                    htons(dev_type) != arp->ar_hrd)
-                       goto out;
+                       goto out_free_skb;
                break;
        case ARPHRD_ETHER:
        case ARPHRD_FDDI:
@@ -690,17 +690,17 @@ static int arp_process(struct net *net, struct sock *sk, struct sk_buff *skb)
                if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
                     arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
                    arp->ar_pro != htons(ETH_P_IP))
-                       goto out;
+                       goto out_free_skb;
                break;
        case ARPHRD_AX25:
                if (arp->ar_pro != htons(AX25_P_IP) ||
                    arp->ar_hrd != htons(ARPHRD_AX25))
-                       goto out;
+                       goto out_free_skb;
                break;
        case ARPHRD_NETROM:
                if (arp->ar_pro != htons(AX25_P_IP) ||
                    arp->ar_hrd != htons(ARPHRD_NETROM))
-                       goto out;
+                       goto out_free_skb;
                break;
        }
 
@@ -708,7 +708,7 @@ static int arp_process(struct net *net, struct sock *sk, struct sk_buff *skb)
 
        if (arp->ar_op != htons(ARPOP_REPLY) &&
            arp->ar_op != htons(ARPOP_REQUEST))
-               goto out;
+               goto out_free_skb;
 
 /*
  *     Extract fields
@@ -733,7 +733,7 @@ static int arp_process(struct net *net, struct sock *sk, struct sk_buff *skb)
  */
        if (ipv4_is_multicast(tip) ||
            (!IN_DEV_ROUTE_LOCALNET(in_dev) && ipv4_is_loopback(tip)))
-               goto out;
+               goto out_free_skb;
 
  /*
   *    For some 802.11 wireless deployments (and possibly other networks),
@@ -741,7 +741,7 @@ static int arp_process(struct net *net, struct sock *sk, struct sk_buff *skb)
   *    and thus should not be accepted.
   */
        if (sip == tip && IN_DEV_ORCONF(in_dev, DROP_GRATUITOUS_ARP))
-               goto out;
+               goto out_free_skb;
 
 /*
  *     Special case: We must set Frame Relay source Q.922 address
@@ -778,7 +778,7 @@ static int arp_process(struct net *net, struct sock *sk, struct sk_buff *skb)
                    !arp_ignore(in_dev, sip, tip))
                        arp_send_dst(ARPOP_REPLY, ETH_P_ARP, sip, dev, tip,
                                     sha, dev->dev_addr, sha, reply_dst);
-               goto out;
+               goto out_consume_skb;
        }
 
        if (arp->ar_op == htons(ARPOP_REQUEST) &&
@@ -803,7 +803,7 @@ static int arp_process(struct net *net, struct sock *sk, struct sk_buff *skb)
                                        neigh_release(n);
                                }
                        }
-                       goto out;
+                       goto out_consume_skb;
                } else if (IN_DEV_FORWARD(in_dev)) {
                        if (addr_type == RTN_UNICAST  &&
                            (arp_fwd_proxy(in_dev, dev, rt) ||
@@ -826,7 +826,7 @@ static int arp_process(struct net *net, struct sock *sk, struct sk_buff *skb)
                                                       in_dev->arp_parms, skb);
                                        goto out_free_dst;
                                }
-                               goto out;
+                               goto out_consume_skb;
                        }
                }
        }
@@ -876,11 +876,16 @@ static int arp_process(struct net *net, struct sock *sk, struct sk_buff *skb)
                neigh_release(n);
        }
 
-out:
+out_consume_skb:
        consume_skb(skb);
+
 out_free_dst:
        dst_release(reply_dst);
-       return 0;
+       return NET_RX_SUCCESS;
+
+out_free_skb:
+       kfree_skb(skb);
+       return NET_RX_DROP;
 }
 
 static void parp_redo(struct sk_buff *skb)
@@ -924,11 +929,11 @@ static int arp_rcv(struct sk_buff *skb, struct net_device *dev,
 
 consumeskb:
        consume_skb(skb);
-       return 0;
+       return NET_RX_SUCCESS;
 freeskb:
        kfree_skb(skb);
 out_of_mem:
-       return 0;
+       return NET_RX_DROP;
 }
 
 /*