From 1c19448c9ba6545b80ded18488a64a7f3d8e6998 Mon Sep 17 00:00:00 2001 From: Tom Herbert Date: Fri, 23 May 2014 08:47:32 -0700 Subject: 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 Signed-off-by: David S. Miller --- net/ipv4/udp.c | 20 +++++++++++++++++++- 1 file changed, 19 insertions(+), 1 deletion(-) (limited to 'net/ipv4') diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index 12c6175b29cd..e07d52b8617a 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -1968,7 +1968,7 @@ int udp_lib_setsockopt(struct sock *sk, int level, int optname, int (*push_pending_frames)(struct sock *)) { struct udp_sock *up = udp_sk(sk); - int val; + int val, valbool; int err = 0; int is_udplite = IS_UDPLITE(sk); @@ -1978,6 +1978,8 @@ int udp_lib_setsockopt(struct sock *sk, int level, int optname, if (get_user(val, (int __user *)optval)) return -EFAULT; + valbool = val ? 1 : 0; + switch (optname) { case UDP_CORK: if (val != 0) { @@ -2007,6 +2009,14 @@ int udp_lib_setsockopt(struct sock *sk, int level, int optname, } break; + case UDP_NO_CHECK6_TX: + up->no_check6_tx = valbool; + break; + + case UDP_NO_CHECK6_RX: + up->no_check6_rx = valbool; + break; + /* * UDP-Lite's partial checksum coverage (RFC 3828). */ @@ -2089,6 +2099,14 @@ int udp_lib_getsockopt(struct sock *sk, int level, int optname, val = up->encap_type; break; + case UDP_NO_CHECK6_TX: + val = up->no_check6_tx; + break; + + case UDP_NO_CHECK6_RX: + val = up->no_check6_rx; + break; + /* The following two cannot be changed on UDP sockets, the return is * always 0 (which corresponds to the full checksum coverage of UDP). */ case UDPLITE_SEND_CSCOV: -- cgit v1.2.3