On 06/26/2018 01:03 AM, Sowmini Varadhan wrote:
On (06/25/18 03:38), Ka-Cheong Poon wrote:
@@ -1105,8 +1105,27 @@ int rds_sendmsg(struct socket *sock, struct msghdr *msg,
size_t payload_len)
break;
case sizeof(*sin6): {
- ret = -EPROTONOSUPPORT;
- goto out;
+ int addr_type;
:
:
+ daddr = sin6->sin6_addr;
+ dport = sin6->sin6_port;
+ scope_id = sin6->sin6_scope_id;
+ break;
}
In rds_sendmsg, the scopeid passed to rds_conn_create_outgoing
may come from the msg_name (if msg_name is a link-local) or
may come from the rs_bound_scope_id (for connected socket, change
made in Patch 1 of the series).
This sounds inconsistent.
If I bind to scopeid if1 and then send to fe80::1%if2 (without connect()),
we'd create an rds_connection with dev_if set to if2.
(first off, its a bit unexpected to be sending to fe80::1%if2 when you
are bound to a link-local on if1!)
But then, if we got back a response from fe80::1%if2, I think we would
not find a matching conn in rds_recv_incoming?
Yes, I think if the socket is bound, it should check the scope_id
in msg_name (if not NULL) to make sure that they match. A bound
RDS socket can send to multiple peers. But if the bound local
address is link local, it should only be allowed to send to peers
on the same link.
And this is even more confusing because the fastpath in rds_sendmsg
does not take the bound_scope_id into consideration at all:
1213 if (rs->rs_conn && ipv6_addr_equal(&rs->rs_conn->c_faddr, &daddr))
1214 conn = rs->rs_conn;
1215 else {
1216 conn = rds_conn_create_outgoing( /* .. */, scope_id)
so if I erroneously passed a msg_name on a connected rds socket, what
would happen? (see also question about rds_connect() itself, below)
The check added above takes care of this. The scope_id should
match.
Should we always use rs_bound_scope_id for creating the outgoing
rds_connection? (you may need something deterministic for this,
like "if bound addr is linklocal, return error if daddr has a different
scopeid, else use the bound addr's scopeid", plus, "if bound addr is
not global, and daddr is link-local, we need a conn with the daddr's
scopeid")
If a socket is bound, I guess the scope_id should be used. So
if a socket is not bound to a link local address and the socket
is used to sent to a link local peer, it should fail.
Also, why is there no IPv6 support in rds_connect?
Oops, I missed this when I ported the internal version to the
net-next version. Will add it back.
--
K. Poon
ka-cheong.p...@oracle.com
