From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-185.mta1.migadu.com (out-185.mta1.migadu.com [95.215.58.185]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E57AB430CCE for ; Thu, 6 Aug 2026 09:17:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.185 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786007824; cv=none; b=T8FIByL0yW/P5CK5W3BrPQ2w+qtVxSAKM8pFN60DVa8WxMEEa0w7g7Z7E8HTSXcggNSOlYDHefzAQZlpkpj6lxB5CMeQ7P2Ht1952ydFSpxBwBHVcjncsQt04/RaKuGHgd92AYpytRKxOYK6Dz5KShV4d7xWAQ5A14PEQ/hDGfw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786007824; c=relaxed/simple; bh=M/RpwFiHSAqoZO4kspus2T4UZyaP30+NjHFm63I8A94=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=AtLYWcb1G4hvHBa5w86VNqcZpzkrMh1iPs8O+X3NdW6sQ3dzPEqvS7oMks16P9uAr+CCzt/d3M7s9SB6v43DxzMucdtCv+qv7eaSeSMdvqRpBLs8eRdvAZTTfDnDs1kJJKKhFo8umhTpLyI3mj7epA5hniY+JVqkZeXrSrmuLGc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=rQ1BdQ8H; arc=none smtp.client-ip=95.215.58.185 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="rQ1BdQ8H" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1786007810; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=gUxTXyO9SEI39IcxI1v9HZ+DOVlkWBmotfQ1Iwo2iyk=; b=rQ1BdQ8HfjPEg8zfw8SwGxjLq2kNRaQEWetS4jP5M0jdIOTwXJ07g+s5mtuUtoLwX1wdIV OfKM67fuEEWd16bYzDOE+ohrgmf32xa2aNbkxY3FcQ1IUEdp3EDsP2aPDxtkBiJ0blCFi8 oBUmZ1jjafbPpLGJ7qgMGYEsCosHPFg= From: Qingfang Deng To: Guillaume Nault , =?UTF-8?q?Pali=20Roh=C3=A1r?= , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Qingfang Deng , Kees Cook , Asim Viladi Oglu Manizada , Eric Woudstra , Felix Fietkau , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Paul Mackerras , Michal Ostrowski Subject: [RFC net-next] pppoe: remove session socket receive support Date: Thu, 6 Aug 2026 17:16:24 +0800 Message-ID: <20260806091626.231225-1-qingfang.deng@linux.dev> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT 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 --- 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