Commit 2cee3e6e authored Oct 13, 2024 by Gur Stavi Committed by Jakub Kicinski Oct 15, 2024

af_packet: allow fanout_add when socket is not RUNNING



PACKET socket can retain its fanout membership through link down and up
and leave a fanout while closed regardless of link state.
However, socket was forbidden from joining a fanout while it was not
RUNNING.

This patch allows PACKET socket to join fanout while not RUNNING.

Socket can be RUNNING if it has a specified protocol. Either directly
from packet_create (being implicitly bound to any interface) or following
a successful bind. Socket RUNNING state is switched off if it is bound to
an interface that went down.

Instead of the test for RUNNING, this patch adds a test that socket can
become RUNNING.

Signed-off-by: Gur Stavi <gur.stavi@huawei.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/4f1a3c37dbef980ef044c4d2adf91c76e2eca14b.1728802323.git.gur.stavi@huawei.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>

parent e3fc5139

net/packet/af_packet.c

+5 −4

Original line number	Diff line number	Diff line
		@@ -1846,21 +1846,22 @@ static int fanout_add(struct sock sk, struct fanout_args args)
		err = -EINVAL;

		spin_lock(&po->bind_lock);
		if (packet_sock_flag(po, PACKET_SOCK_RUNNING) &&
		if (po->num &&
		match->type == type &&
		match->prot_hook.type == po->prot_hook.type &&
		match->prot_hook.dev == po->prot_hook.dev) {
		err = -ENOSPC;
		if (refcount_read(&match->sk_ref) < match->max_num_members) {
		__dev_remove_pack(&po->prot_hook);

		/* Paired with packet_setsockopt(PACKET_FANOUT_DATA) */
		WRITE_ONCE(po->fanout, match);

		po->rollover = rollover;
		rollover = NULL;
		refcount_set(&match->sk_ref, refcount_read(&match->sk_ref) + 1);
		if (packet_sock_flag(po, PACKET_SOCK_RUNNING)) {
		__dev_remove_pack(&po->prot_hook);
		__fanout_link(sk, po);
		}
		err = 0;
		}
		}