sock: sockc cookie initializer

Initialize the cookie in one location to reduce code duplication and
avoid bugs from inconsistent initialization, such as that fixed in
commit 9887cba19978 ("ip: limit use of gso_size to udp").

Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 10 insertions, 7 deletions

diff --git a/include/net/sock.h b/include/net/sock.h
index e0eac9ef44b5..83b747538bd0 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1600,6 +1600,12 @@ struct sockcm_cookie {
         u16 tsflags;
 };
 
+static inline void sockcm_init(struct sockcm_cookie *sockc,
+                               const struct sock *sk)
+{
+        *sockc = (struct sockcm_cookie) { .tsflags = sk->sk_tsflags };
+}
+
 int __sock_cmsg_send(struct sock *sk, struct msghdr *msg, struct cmsghdr *cmsg,
                      struct sockcm_cookie *sockc);
 int sock_cmsg_send(struct sock *sk, struct msghdr *msg,
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index bf461fa77ed6..850dc8f15afc 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1241,7 +1241,7 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
                 /* 'common' sending to sendq */
         }
 
-        sockc.tsflags = sk->sk_tsflags;
+        sockcm_init(&sockc, sk);
         if (msg->msg_controllen) {
                 err = sock_cmsg_send(sk, msg, &sockc);
                 if (unlikely(err)) {
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 3428f7739ae9..47931ebfaef3 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -1951,8 +1951,7 @@ retry:
                 goto out_unlock;
         }
 
-        sockc.transmit_time = 0;
-        sockc.tsflags = sk->sk_tsflags;
+        sockcm_init(&sockc, sk);
         if (msg->msg_controllen) {
                 err = sock_cmsg_send(sk, msg, &sockc);
                 if (unlikely(err))
@@ -2636,8 +2635,7 @@ static int tpacket_snd(struct packet_sock *po, struct msghdr *msg)
         if (unlikely(!(dev->flags & IFF_UP)))
                 goto out_put;
 
-        sockc.transmit_time = 0;
-        sockc.tsflags = po->sk.sk_tsflags;
+        sockcm_init(&sockc, &po->sk);
         if (msg->msg_controllen) {
                 err = sock_cmsg_send(&po->sk, msg, &sockc);
                 if (unlikely(err))
@@ -2833,8 +2831,7 @@ static int packet_snd(struct socket *sock, struct msghdr *msg, size_t len)
         if (unlikely(!(dev->flags & IFF_UP)))
                 goto out_unlock;
 
-        sockc.transmit_time = 0;
-        sockc.tsflags = sk->sk_tsflags;
+        sockcm_init(&sockc, sk);
         sockc.mark = sk->sk_mark;
         if (msg->msg_controllen) {
                 err = sock_cmsg_send(sk, msg, &sockc);