net: Make enabling of zero UDP6 csums more restrictive
RFC 6935 permits zero checksums to be used in IPv6 however this is
recommended only for certain tunnel protocols, it does not make
checksums completely optional like they are in IPv4.
This patch restricts the use of IPv6 zero checksums that was previously
intoduced. no_check6_tx and no_check6_rx have been added to control
the use of checksums in UDP6 RX and TX path. The normal
sk_no_check_{rx,tx} settings are not used (this avoids ambiguity when
dealing with a dual stack socket).
A helper function has been added (udp_set_no_check6) which can be
called by tunnel impelmentations to all zero checksums (send on the
socket, and accept them as valid).
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index b8db453..6032523 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -794,10 +794,10 @@
dif = inet6_iif(skb);
sk = udp_v6_mcast_next(net, sk, uh->dest, daddr, uh->source, saddr, dif);
while (sk) {
- /* If zero checksum and sk_no_check is not on for
+ /* If zero checksum and no_check is not on for
* the socket then skip it.
*/
- if (uh->check || sk->sk_no_check_rx)
+ if (uh->check || udp_sk(sk)->no_check6_rx)
stack[count++] = sk;
sk = udp_v6_mcast_next(net, sk_nulls_next(sk), uh->dest, daddr,
@@ -887,7 +887,7 @@
if (sk != NULL) {
int ret;
- if (!uh->check && !sk->sk_no_check_rx) {
+ if (!uh->check && !udp_sk(sk)->no_check6_rx) {
sock_put(sk);
udp6_csum_zero_error(skb);
goto csum_error;
@@ -1037,7 +1037,7 @@
if (is_udplite)
csum = udplite_csum_outgoing(sk, skb);
- else if (sk->sk_no_check_tx) { /* UDP csum disabled */
+ else if (up->no_check6_tx) { /* UDP csum disabled */
skb->ip_summed = CHECKSUM_NONE;
goto send;
} else if (skb->ip_summed == CHECKSUM_PARTIAL) { /* UDP hardware csum */