[PATCH net-next 3/6] sock: sockc cookie initializer

[Willem de Bruijn]

From: Willem de Bruijn <will...@google.com>

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 <will...@google.com>
---
 include/net/sock.h     | 6 ++++++
 net/ipv4/tcp.c         | 2 +-
 net/packet/af_packet.c | 9 +++------
 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 @@ static int packet_sendmsg_spkt(struct socket *sock, 
struct msghdr *msg,
                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);
-- 
2.18.0.399.gad0ab374a1-goog