udp: Add support for doing checksum unnecessary conversion

Add support for doing CHECKSUM_UNNECESSARY to CHECKSUM_COMPLETE
conversion in UDP tunneling path.

In the normal UDP path, we call skb_checksum_try_convert after locating
the UDP socket. The check is that checksum conversion is enabled for
the socket (new flag in UDP socket) and that checksum field is
non-zero.

In the UDP GRO path, we call skb_gro_checksum_try_convert after
checksum is validated and checksum field is non-zero. Since this is
already in GRO we assume that checksum conversion is always wanted.

Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 15 insertions, 1 deletions

diff --git a/include/linux/udp.h b/include/linux/udp.h
index 247cfdcc4b08..ee3277593222 100644
--- a/include/linux/udp.h
+++ b/include/linux/udp.h
@@ -49,7 +49,11 @@ struct udp_sock {
         unsigned int     corkflag;      /* Cork is required */
         __u8             encap_type;    /* Is this an Encapsulation socket? */
         unsigned char    no_check6_tx:1,/* Send zero UDP6 checksums on TX? */
-                         no_check6_rx:1;/* Allow zero UDP6 checksums on RX? */
+                         no_check6_rx:1,/* Allow zero UDP6 checksums on RX? */
+                         convert_csum:1;/* On receive, convert checksum
+                                         * unnecessary to checksum complete
+                                         * if possible.
+                                         */
         /*
          * Following member retains the information to create a UDP header
          * when the socket is uncorked.
@@ -98,6 +102,16 @@ static inline bool udp_get_no_check6_rx(struct sock *sk)
         return udp_sk(sk)->no_check6_rx;
 }
 
+static inline void udp_set_convert_csum(struct sock *sk, bool val)
+{
+        udp_sk(sk)->convert_csum = val;
+}
+
+static inline bool udp_get_convert_csum(struct sock *sk)
+{
+        return udp_sk(sk)->convert_csum;
+}
+
 #define udp_portaddr_for_each_entry(__sk, node, list) \
         hlist_nulls_for_each_entry(__sk, node, list, __sk_common.skc_portaddr_node)