Gur Stavi wrote:
> 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.
>
> The previous test for RUNNING also implicitly tested that the socket is
> bound to a device. An explicit test of ifindex was added instead.
>
> Signed-off-by: Gur Stavi <gur.stavi@xxxxxxxxxx>
> ---
> net/packet/af_packet.c | 35 +++++++++++++++++++++--------------
> 1 file changed, 21 insertions(+), 14 deletions(-)
>
> diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
> index f8942062f776..8137c33ab0fd 100644
> --- a/net/packet/af_packet.c
> +++ b/net/packet/af_packet.c
> @@ -1843,26 +1843,29 @@ static int fanout_add(struct sock *sk, struct fanout_args *args)
> match->prot_hook.ignore_outgoing = type_flags & PACKET_FANOUT_FLAG_IGNORE_OUTGOING;
> list_add(&match->list, &fanout_list);
> }
> - err = -EINVAL;
>
> spin_lock(&po->bind_lock);
> - if (packet_sock_flag(po, PACKET_SOCK_RUNNING) &&
> - match->type == type &&
> - match->prot_hook.type == po->prot_hook.type &&
> - match->prot_hook.dev == po->prot_hook.dev) {
> + if (po->ifindex == -1 || po->num == 0) {
This patch is more complex than it needs to be.
No need to block the case of ETH_P_NONE or not bound to a socket.
I would have discussed that in v2, but you already respun.
> + /* Socket can not receive packets */
> + err = -ENXIO;
> + } else if (match->type != type ||
> + match->prot_hook.type != po->prot_hook.type ||
> + match->prot_hook.dev != po->prot_hook.dev) {
> + /* Joining an existing group, properties must be identical */
> + err = -EINVAL;
> + } else if (refcount_read(&match->sk_ref) >= match->max_num_members) {
> err = -ENOSPC;
> - if (refcount_read(&match->sk_ref) < match->max_num_members) {
> + } else {
> + /* 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);
> -
> - /* 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);
> __fanout_link(sk, po);
> - err = 0;
> }
> + err = 0;
> }
> spin_unlock(&po->bind_lock);
>
> @@ -3452,8 +3455,12 @@ static int packet_create(struct net *net, struct socket *sock, int protocol,
> po->prot_hook.af_packet_net = sock_net(sk);
>
> if (proto) {
> + /* Implicitly bind socket to "any interface" */
> + po->ifindex = 0;
> po->prot_hook.type = proto;
> __register_prot_hook(sk);
> + } else {
> + po->ifindex = -1;
> }
>
> mutex_lock(&net->packet.sklist_lock);
> --
> 2.45.2
>
