[RFC net-next] pppoe: remove session socket receive support
From: Qingfang Deng <hidden>
Date: 2026-08-06 09:16:53
Also in:
lkml
Subsystem:
networking drivers, ppp over ethernet, the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
No known userspace PPPoE implementation reads from an AF_PPPOX socket. In particular, pppd uses the socket only to establish a session and obtain a generic PPP channel with PPPIOCGCHAN. Packet I/O then uses /dev/ppp. Before this change, packets received before PPPIOCGCHAN set PPPOX_BOUND were queued on sk_receive_queue. Since no known implementation consumed them, they remained there until socket destruction and unnecessarily consumed memory. Pass every matched session packet directly to ppp_input(). On a successful connect, the channel is registered before the socket lock is released. Generic PPP can therefore queue early packets until userspace attaches /dev/ppp, preserving packets that arrive between connect() and PPPIOCGCHAN. Replace pppoe_recvmsg() with sock_no_recvmsg(). Like PPTP, omit the poll callback because the socket no longer receives packets. Remove pppoe_destruct() because the receive queue is no longer used. Assisted-by: Codex:GPT-5.6 Signed-off-by: Qingfang Deng <redacted> --- drivers/net/ppp/pppoe.c | 50 ++--------------------------------------- 1 file changed, 2 insertions(+), 48 deletions(-)
diff --git a/drivers/net/ppp/pppoe.c b/drivers/net/ppp/pppoe.c
index bf7414b46a26..e3d425943c76 100644
--- a/drivers/net/ppp/pppoe.c
+++ b/drivers/net/ppp/pppoe.c@@ -350,23 +350,9 @@ static int pppoe_rcv_core(struct sock *sk, struct sk_buff *skb) { struct pppox_sock *po = pppox_sk(sk); - /* Backlog receive. Semantics of backlog rcv preclude any code from - * executing in lock_sock()/release_sock() bounds; meaning sk->sk_state - * can't change. - */ - - if (sk->sk_state & PPPOX_BOUND) { - ppp_input(&po->chan, skb); - } else { - if (sock_queue_rcv_skb(sk, skb)) - goto abort_kfree; - } + ppp_input(&po->chan, skb); return NET_RX_SUCCESS; - -abort_kfree: - kfree_skb(skb); - return NET_RX_DROP; } /************************************************************************
@@ -498,11 +484,6 @@ static struct proto pppoe_sk_proto __read_mostly = { .obj_size = sizeof(struct pppox_sock), }; -static void pppoe_destruct(struct sock *sk) -{ - skb_queue_purge(&sk->sk_receive_queue); -} - /*********************************************************************** * * Initialize a new struct sock.
@@ -523,7 +504,6 @@ static int pppoe_create(struct net *net, struct socket *sock, int kern) sock->ops = &pppoe_ops; sk->sk_backlog_rcv = pppoe_rcv_core; - sk->sk_destruct = pppoe_destruct; sk->sk_state = PPPOX_NONE; sk->sk_type = SOCK_STREAM; sk->sk_family = PF_PPPOX;
@@ -921,31 +901,6 @@ static const struct ppp_channel_ops pppoe_chan_ops = { .fill_forward_path = pppoe_fill_forward_path, }; -static int pppoe_recvmsg(struct socket *sock, struct msghdr *m, - size_t total_len, int flags) -{ - struct sock *sk = sock->sk; - struct sk_buff *skb; - int error = 0; - - if (sk->sk_state & PPPOX_BOUND) - return -EIO; - - skb = skb_recv_datagram(sk, flags, &error); - if (!skb) - return error; - - total_len = min_t(size_t, total_len, skb->len); - error = skb_copy_datagram_msg(skb, 0, m, total_len); - if (error == 0) { - consume_skb(skb); - return total_len; - } - - kfree_skb(skb); - return error; -} - #ifdef CONFIG_PROC_FS static int pppoe_seq_show(struct seq_file *seq, void *v) {
@@ -1046,11 +1001,10 @@ static const struct proto_ops pppoe_ops = { .socketpair = sock_no_socketpair, .accept = sock_no_accept, .getname = pppoe_getname, - .poll = datagram_poll, .listen = sock_no_listen, .shutdown = sock_no_shutdown, .sendmsg = pppoe_sendmsg, - .recvmsg = pppoe_recvmsg, + .recvmsg = sock_no_recvmsg, .mmap = sock_no_mmap, .ioctl = pppox_ioctl, #ifdef CONFIG_COMPAT
--
2.43.0