[PATCH net 1/3] net: datagram: introduce datagram_poll_queue for custom receive queues
From: Ralf Lici <hidden>
Date: 2025-10-16 14:22:46
Subsystem:
networking [general], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Some protocols using TCP encapsulation (e.g., espintcp, openvpn) deliver userspace-bound packets through a custom skb queue rather than the standard sk_receive_queue. Introduce datagram_poll_queue that accepts an explicit receive queue, and convert datagram_poll into a wrapper around datagram_poll_queue. This allows protocols with custom skb queues to reuse the core polling logic without relying on sk_receive_queue. Cc: Sabrina Dubroca <sd@queasysnail.net> Cc: Antonio Quartulli <antonio@openvpn.net> Signed-off-by: Ralf Lici <redacted> --- include/linux/skbuff.h | 3 +++ net/core/datagram.c | 45 +++++++++++++++++++++++++++++------------- 2 files changed, 34 insertions(+), 14 deletions(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index fb3fec9affaa..a7cc3d1f4fd1 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h@@ -4204,6 +4204,9 @@ struct sk_buff *__skb_recv_datagram(struct sock *sk, struct sk_buff_head *sk_queue, unsigned int flags, int *off, int *err); struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned int flags, int *err); +__poll_t datagram_poll_queue(struct file *file, struct socket *sock, + struct poll_table_struct *wait, + struct sk_buff_head *rcv_queue); __poll_t datagram_poll(struct file *file, struct socket *sock, struct poll_table_struct *wait); int skb_copy_datagram_iter(const struct sk_buff *from, int offset,
diff --git a/net/core/datagram.c b/net/core/datagram.c
index cb4b9ef2e4e3..60e69d0b6aa0 100644
--- a/net/core/datagram.c
+++ b/net/core/datagram.c@@ -920,21 +920,18 @@ int skb_copy_and_csum_datagram_msg(struct sk_buff *skb, EXPORT_SYMBOL(skb_copy_and_csum_datagram_msg); /** - * datagram_poll - generic datagram poll - * @file: file struct - * @sock: socket - * @wait: poll table - * - * Datagram poll: Again totally generic. This also handles - * sequenced packet sockets providing the socket receive queue - * is only ever holding data ready to receive. + * datagram_poll_queue - same as datagram_poll, but on a specific receive queue + * @file: file struct + * @sock: socket + * @wait: poll table + * @rcv_queue: receive queue to poll * - * Note: when you *don't* use this routine for this protocol, - * and you use a different write policy from sock_writeable() - * then please supply your own write_space callback. + * Performs polling on the given receive queue, handling shutdown, error, and + * connection state. This is useful for protocols that deliver userspace-bound + * packets through a custom queue instead of sk->sk_receive_queue. */ -__poll_t datagram_poll(struct file *file, struct socket *sock, - poll_table *wait) +__poll_t datagram_poll_queue(struct file *file, struct socket *sock, + poll_table *wait, struct sk_buff_head *rcv_queue) { struct sock *sk = sock->sk; __poll_t mask;
@@ -956,7 +953,7 @@ __poll_t datagram_poll(struct file *file, struct socket *sock, mask |= EPOLLHUP; /* readable? */ - if (!skb_queue_empty_lockless(&sk->sk_receive_queue)) + if (!skb_queue_empty_lockless(rcv_queue)) mask |= EPOLLIN | EPOLLRDNORM; /* Connection-based need to check for termination and startup */
@@ -978,4 +975,24 @@ __poll_t datagram_poll(struct file *file, struct socket *sock, return mask; } +EXPORT_SYMBOL(datagram_poll_queue); + +/** + * datagram_poll - generic datagram poll + * @file: file struct + * @sock: socket + * @wait: poll table + * + * Datagram poll: Again totally generic. This also handles + * sequenced packet sockets providing the socket receive queue + * is only ever holding data ready to receive. + * + * Note: when you *don't* use this routine for this protocol, + * and you use a different write policy from sock_writeable() + * then please supply your own write_space callback. + */ +__poll_t datagram_poll(struct file *file, struct socket *sock, poll_table *wait) +{ + return datagram_poll_queue(file, sock, wait, &sock->sk->sk_receive_queue); +} EXPORT_SYMBOL(datagram_poll);
--
2.51.0