Tons of "ICMPv6 checksum failed" in the logs

[Kalin KOZHUHAROV <kalin@ThinRope.net>]

I hope this is the right ML to post, if not please enlighten me where to ask :-)

With 2.6.5 I started experiemnting with IPv6 and now most everything is working OK.

However I found tons of the following in kernel logs:

May 14 05:39:40 [kernel] ICMPv6 checksum failed [2001:0200:0000:1800:0000:0000:09c4:0002 > 2001:02f8:0040:0002:020e:0cff:fe07:898b]
May 14 05:39:47 [kernel] ICMPv6 checksum failed [2001:0200:0000:1800:0000:0000:2497:0000 > 2001:02f8:0040:0002:020e:0cff:fe07:898b]
May 14 09:34:27 [kernel] ICMPv6 checksum failed [fe80:0000:0000:0000:0240:66ff:fe10:c062 > ff02:0000:0000:0000:0000:0000:0000:0001]
                - Last output repeated 5 times -
May 14 16:55:42 [kernel] ICMPv6 checksum failed [2001:0240:0517:0001:0000:0000:0000:0002 > 2001:02f8:0040:0002:020e:0cff:fe07:898b]
May 14 16:55:42 [kernel] ICMPv6 checksum failed [2001:02f8:0001:0000:0000:0000:0000:0009 > 2001:02f8:0040:0002:020e:0cff:fe07:898b]

Searching on google, for "ICMPv6 checksum failed" got me some mostly irrelevant results :-(

I also found some patches for 2.6.6 of the kind:

diff -Nru a/net/ipv6/icmp.c b/net/ipv6/icmp.c
--- a/net/ipv6/icmp.c   Tue Apr 27 18:37:22 2004
+++ b/net/ipv6/icmp.c   Tue Apr 27 18:37:22 2004
@@ -570,17 +570,17 @@
       skb->ip_summed = CHECKSUM_UNNECESSARY;
       if (csum_ipv6_magic(saddr, daddr, skb->len, IPPROTO_ICMPV6,
                 skb->csum)) {
-         if (net_ratelimit())
-            printk(KERN_DEBUG "ICMPv6 hw checksum failed\n");
+         LIMIT_NETDEBUG(
+            printk(KERN_DEBUG "ICMPv6 hw checksum failed\n"));
          skb->ip_summed = CHECKSUM_NONE;
       }
    }
    if (skb->ip_summed == CHECKSUM_NONE) {
       if (csum_ipv6_magic(saddr, daddr, skb->len, IPPROTO_ICMPV6,
                 skb_checksum(skb, 0, skb->len, 0))) {
-         if (net_ratelimit())
+         LIMIT_NETDEBUG(
             printk(KERN_DEBUG "ICMPv6 checksum failed [%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x > %04x:%04x:%04x:%04x:%04x:%04x:%+
04x:%04x]\n",
-                   NIP6(*saddr), NIP6(*daddr));
+                   NIP6(*saddr), NIP6(*daddr)));
          goto discard_it;
       }
    }

[ Full patch at http://www.linuxhq.com/kernel/v2.6/6-rc3/net/ipv6/icmp.c ]

And looking on my 2.6.6 machine, there are just a few of these errors in the log.

Does this mean that they don't happen or they are just not logged (because of LIMIT_NETDEBUG )?

Anyway, are these errors of any concern at all? I have really no idea what they mean, just the word error seems bad to me :-|

I will provide any information (.config, lspci, etc.) if needed.

Kalin.

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