[PATCH net-next v18 13/25] skb: implement skb_send_sock_locked_with_flags()

Antonio Quartulli
2025-01-13T09:31:22Z

When sending an skb over a socket using skb_send_sock_locked(),
it is currently not possible to specify any flag to be set in
msghdr->msg_flags.

However, we may want to pass flags the user may have specified,
like MSG_NOSIGNAL.

Extend __skb_send_sock() with a new argument 'flags' and add a
new interface named skb_send_sock_locked_with_flags().

Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Simon Horman <horms@kernel.org>
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
---
include/linux/skbuff.h | 2 ++
net/core/skbuff.c | 18 +++++++++++++-----
2 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index bb2b751d274acff931281a72e8b4b0c699b4e8af..c7afa7871e1c26e0caad4f77facf8a225425bce5 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -4162,6 +4162,8 @@ int skb_splice_bits(struct sk_buff *skb, struct sock *sk, unsigned int offset,
unsigned int flags);
int skb_send_sock_locked(struct sock *sk, struct sk_buff *skb, int offset,
int len);
+int skb_send_sock_locked_with_flags(struct sock *sk, struct sk_buff *skb,
+ int offset, int len, int flags);
int skb_send_sock(struct sock *sk, struct sk_buff *skb, int offset, int len);
void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to);
unsigned int skb_zerocopy_headlen(const struct sk_buff *from);
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index a441613a1e6c1765f7fc2e40f982b81f8f8fdb96..e83327bcbce37625f5c0b8b0581d6e3bf5fb55a5 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3267,7 +3267,7 @@ static int sendmsg_unlocked(struct sock *sk, struct msghdr *msg)

typedef int (*sendmsg_func)(struct sock *sk, struct msghdr *msg);
static int __skb_send_sock(struct sock *sk, struct sk_buff *skb, int offset,
- int len, sendmsg_func sendmsg)
+ int len, sendmsg_func sendmsg, int flags)
{
unsigned int orig_len = len;
struct sk_buff *head = skb;
@@ -3285,7 +3285,7 @@ static int __skb_send_sock(struct sock *sk, struct sk_buff *skb, int offset,
kv.iov_base = skb->data + offset;
kv.iov_len = slen;
memset(&msg, 0, sizeof(msg));
- msg.msg_flags = MSG_DONTWAIT;
+ msg.msg_flags = MSG_DONTWAIT | flags;

iov_iter_kvec(&msg.msg_iter, ITER_SOURCE, &kv, 1, slen);
ret = INDIRECT_CALL_2(sendmsg, sendmsg_locked,
@@ -3322,7 +3322,8 @@ static int __skb_send_sock(struct sock *sk, struct sk_buff *skb, int offset,
while (slen) {
struct bio_vec bvec;
struct msghdr msg = {
- .msg_flags = MSG_SPLICE_PAGES | MSG_DONTWAIT,
+ .msg_flags = MSG_SPLICE_PAGES | MSG_DONTWAIT |
+ flags,
};

bvec_set_page(&bvec, skb_frag_page(frag), slen,
@@ -3368,14 +3369,21 @@ static int __skb_send_sock(struct sock *sk, struct sk_buff *skb, int offset,
int skb_send_sock_locked(struct sock *sk, struct sk_buff *skb, int offset,
int len)
{
- return __skb_send_sock(sk, skb, offset, len, sendmsg_locked);
+ return __skb_send_sock(sk, skb, offset, len, sendmsg_locked, 0);
}
EXPORT_SYMBOL_GPL(skb_send_sock_locked);

+int skb_send_sock_locked_with_flags(struct sock *sk, struct sk_buff *skb,
+ int offset, int len, int flags)
+{
+ return __skb_send_sock(sk, skb, offset, len, sendmsg_locked, flags);
+}
+EXPORT_SYMBOL_GPL(skb_send_sock_locked_with_flags);
+
/* Send skb data on a socket. Socket must be unlocked. */
int skb_send_sock(struct sock *sk, struct sk_buff *skb, int offset, int len)
{
- return __skb_send_sock(sk, skb, offset, len, sendmsg_unlocked);
+ return __skb_send_sock(sk, skb, offset, len, sendmsg_unlocked, 0);
}

/**

--
2.45.2