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authorTom Herbert <therbert@google.com>2014-05-02 16:29:58 -0700
committerDavid S. Miller <davem@davemloft.net>2014-05-05 15:26:30 -0400
commit4068579e1e098fa81d48db9ba4432ab664c58561 (patch)
tree19aa4761b4381904203def58cf90abb6ae96cebe /net/ipv6/ip6_checksum.c
parente4f45b7f40bdaade5ef8f45e7c6daed4c909fdf5 (diff)
net: Implmement RFC 6936 (zero RX csums for UDP/IPv6)
RFC 6936 relaxes the requirement of RFC 2460 that UDP/IPv6 packets which are received with a zero UDP checksum value must be dropped. RFC 6936 allows zero checksums to support tunnels over UDP. When sk_no_check is set we allow on a socket we allow a zero IPv6 UDP checksum. This is for both sending zero checksum and accepting a zero checksum on receive. Signed-off-by: Tom Herbert <therbert@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6/ip6_checksum.c')
-rw-r--r--net/ipv6/ip6_checksum.c18
1 files changed, 7 insertions, 11 deletions
diff --git a/net/ipv6/ip6_checksum.c b/net/ipv6/ip6_checksum.c
index c69fe37b8104..da26224a5993 100644
--- a/net/ipv6/ip6_checksum.c
+++ b/net/ipv6/ip6_checksum.c
@@ -75,16 +75,12 @@ int udp6_csum_init(struct sk_buff *skb, struct udphdr *uh, int proto)
return err;
}
- if (uh->check == 0) {
- /* RFC 2460 section 8.1 says that we SHOULD log
- this error. Well, it is reasonable.
- */
- LIMIT_NETDEBUG(KERN_INFO "IPv6: udp checksum is 0 for [%pI6c]:%u->[%pI6c]:%u\n",
- &ipv6_hdr(skb)->saddr, ntohs(uh->source),
- &ipv6_hdr(skb)->daddr, ntohs(uh->dest));
- return 1;
- }
-
- return skb_checksum_init(skb, IPPROTO_UDP, ip6_compute_pseudo);
+ /* To support RFC 6936 (allow zero checksum in UDP/IPV6 for tunnels)
+ * we accept a checksum of zero here. When we find the socket
+ * for the UDP packet we'll check if that socket allows zero checksum
+ * for IPv6 (set by socket option).
+ */
+ return skb_checksum_init_zero_check(skb, proto, uh->check,
+ ip6_compute_pseudo);
}
EXPORT_SYMBOL(udp6_csum_init);

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