Re: [PATCH net-next v03 1/3] af_packet: allow fanout_add when socket is not RUNNING

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@huawei.com

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