Gur Stavi wrote:
Gur Stavi wrote:
@@ -1846,21 +1846,21 @@ 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) &&
match->type == type &&
- if (match->type == type && match->prot_hook.type == po->prot_hook.type && match->prot_hook.dev == po->prot_hook.dev) {
Remaining unaddressed issue is that the socket can now be added before being bound. See comment in v1.
I extended the psock_fanout test with unbound fanout test.
As far as I understand, the easiest way to verify bind is to test that po->prot_hook.dev != NULL, since we are under a bind_lock anyway. But perhaps a more readable and direct approach to test "bind" would be to test po->ifindex != -1, as ifindex is commented as "bound device". However, at the moment ifindex is not initialized to -1, I can add such initialization, but perhaps I do not fully understand all the logic.
Any preferences?
prot_hook.dev is not necessarily set if a packet socket is bound. It may be bound to any device. See dev_add_pack and ptype_head.
prot_hook.type, on the other hand, must be set if bound and is only modified with the bind_lock held too.
Well, and in packet_create. But setsockopt PACKET_FANOUT_ADD also succeeds in case bind() was not called explicitly first to bind to a specific device or change ptype.
Please clarify the last paragraph? When you say "also succeeds" do you mean SHOULD succeed or MAY SUCCEED by mistake if "something" happens ???
I mean it succeeds currently. Which behavior must then be maintained.
Do you refer to the following scenario: socket is created with non-zero protocol and becomes RUNNING "without bind" for all devices. In that case it can be added to FANOUT without bind. Is that considered a bug or does the bind requirement for fanout only apply for all-protocol (0) sockets?
I'm beginning to think that this bind requirement is not needed.
All type and dev are valid, even if an ETH_P_NONE fanout group would be fairly useless.
The type and dev must match that of the fanout group, and once added to a fanout group can no longer be changed (bind will fail).
I briefy considered the reason might be max_num_members accounting. Since f->num_members counts running sockets. But that is not used when tracking membership of the group, sk_ref is. Every packet socket whose po->rollover is increased increases this refcount.
What about using ifindex to detect bind? Initialize it to -1 in packet_create and ensure that packet_do_bind, on success, sets it to device id or 0?
psock_fanout, should probably be extended with scenarios that test "all devices" and all/specific protocols. Any specific scenario suggestions?