Skip to contentSkip to conversation

Reverse sense of promisc tests in ip6_mc_input

PATCH In review Corey Mutter 3 participants 3 messages May 12, 2007 – May 14, 2007

Subsystems (3)
Networking Network drivers IPv4/IPv6
lore
Share & tools
lore

Corey Mutter

author
#0 lore raw

PATCH 1/1 Reverse sense of promisc tests in ip6_mc_input

From: Corey Mutter <[email protected]>

Reverse the sense of the promiscuous-mode tests in ip6_mc_input().

Signed-off-by Corey Mutter <[email protected]>

---

I had been suspicious of this code for a while, but just assumed I must have been missing something. However, I did some tests and, sure enough, I can open a socket and it will see IPv6 multicast packets come in, then the packets will stop coming in when I turn on IFF_ALLMULTI on the interface.

In my tests, this change works more like I'd expect; I can open a socket, and it doesn't see any multicast packets (unless I join a group or something) until after I turn on IFF_ALLMULTI.

net/ipv6/ip6_input.c +1 -1
@@ -235,7 +235,7 @@ int ip6_mc_input(struct sk_buff *skb)
 	IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_INMCASTPKTS);
 
 	hdr = skb->nh.ipv6h;
-	deliver = likely(!(skb->dev->flags & (IFF_PROMISC|IFF_ALLMULTI))) ||
+	deliver = unlikely(skb->dev->flags & (IFF_PROMISC|IFF_ALLMULTI)) ||
 	    ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, NULL);
 
 	/*
#1 lore raw

Your patch looks correct to me.

                        +-DLS
Signed-off-by David L Stevens <[email protected]>

[email protected] wrote on 05/12/2007 03:51:35 PM:

Quoted 13 lines

From: Corey Mutter <[email protected]>

Reverse the sense of the promiscuous-mode tests in ip6_mc_input().

Signed-off-by Corey Mutter <[email protected]>

---

I had been suspicious of this code for a while, but just assumed I must have been missing something. However, I did some tests and, sure enough,

I can open a socket and it will see IPv6 multicast packets come in, then

Quoted 8 lines

the packets will stop coming in when I turn on IFF_ALLMULTI on the interface.

In my tests, this change works more like I'd expect; I can open a socket, and it doesn't see any multicast packets (unless I join a group or something) until after I turn on IFF_ALLMULTI.

--- linux-2.6.21.1/net/ipv6/ip6_input.c 2007-04-27 17:49:26.000000000

-0400

Quoted 14 lines

+++ linux/net/ipv6/ip6_input.c 2007-05-12 18:19:09.597750000 -0400

net/ipv6/ip6_input.c +1 -2
@@ -235,7 +235,7 @@ int ip6_mc_input(struct sk_buff *skb)
    IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_INMCASTPKTS);
 
    hdr = skb->nh.ipv6h;
-   deliver = likely(!(skb->dev->flags & (IFF_PROMISC|IFF_ALLMULTI))) ||
+   deliver = unlikely(skb->dev->flags & (IFF_PROMISC|IFF_ALLMULTI)) ||
        ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, NULL);
 
    /*
-

To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html