skb: implement skb_send_sock_locked_with_flags()

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>
Link: https://patch.msgid.link/20250415-b4-ovpn-v26-12-577f6097b964@openvpn.net
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index f1381aff0f896220b2b6bc706aaca17b8f28fd8b..beb084ee4f4d2a83165e08d3a5918d0bc9bfc069 100644 (file)
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -4145,6 +4145,8 @@ 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 74a2d886a35b518d55b6d3cafcb8442212f9beee..d73ad79fe739d1c412615ed01f0850dbf4c9e09e 100644 (file)
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3227,7 +3227,7 @@ 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;
@@ -3245,7 +3245,7 @@ do_frag_list:
                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,
@@ -3282,7 +3282,8 @@ do_frag_list:
                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,
@@ -3328,14 +3329,21 @@ error:
 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);
 }
 
 /**