ARP bug and a patch

[zhongyu]

	Bug's description :
	A computer has two ethernet cards connected to the same hub, each ethernet card was in a
different logical sub net and turn on the ip_forward on each ethernet card. Dozens of ARP request
packet will cause a "neibour table overflow"
error then the netcard can not work .
	reason:
	The arp_rcv fuction would call the ip_route_input function to build the dst entry of the skb.
When the ip_forward is on , the code will run direct into the rt_intern_hash fuction which add the
target ip to the neighbour buffer . 
	patch:

diff -Naur linux-2.4.9/net/ipv4/route.c linux-2.4.9n/net/ipv4/route.c
--- linux-2.4.9/net/ipv4/route.c        Fri Nov 16 17:19:06 2001
+++ linux-2.4.9n/net/ipv4/route.c       Fri Nov 16 17:17:59 2001
@@ -1501,6 +1501,12 @@
        }
 #endif

+       if (skb->protocol == __constant_htons(ETH_P_ARP)){      
+               skb->dst = rth;
+               err = 0;
+               goto done;
+       }
+       
 intern:
        err = rt_intern_hash(hash, rth, (struct rtable**)&skb->dst);
 done:

          zhongyu
            [e-mail]

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