On Mon, Jun 27, 2022 at 01:29:26AM +0300, Vitaliy Makkoveev wrote:
> We should check PIPEX_SFLAGS_IP{,6}_FORWARD bits on the session which we
> will output packet, not on the dummy multicast session.
>
> npppd(8) clears these flags before release IP address assigned to
> session. So this IP address could be assigned to other session while our
> session is still alive.
>
> We should also do this check within pppx_if_qstart(), but I want to do
> this with separate diff.
>
> Index: sys/net/pipex.c
> ===================================================================
> RCS file: /cvs/src/sys/net/pipex.c,v
> retrieving revision 1.138
> diff -u -p -r1.138 pipex.c
> --- sys/net/pipex.c 26 Jun 2022 15:50:21 -0000 1.138
> +++ sys/net/pipex.c 26 Jun 2022 22:16:17 -0000
> @@ -801,7 +801,7 @@ pipex_ip_output(struct mbuf *m0, struct
> LIST_FOREACH(session_tmp, &pipex_session_list, session_list) {
> if (session_tmp->ownersc != session->ownersc)
> continue;
> - if ((session->flags & (PIPEX_SFLAGS_IP_FORWARD |
> + if ((session_tmp->flags & (PIPEX_SFLAGS_IP_FORWARD |
> PIPEX_SFLAGS_IP6_FORWARD)) == 0)
> continue;
> m = m_copym(m0, 0, M_COPYALL, M_NOWAIT);
>
I changed my opinion about PIPEX_SFLAGS_IP{,6}_FORWARD flags in pipex(4)
output path. We have a lot of buffers between pipex(4) server and ppp
client. Some of such buffers could be located in other routers. And
outgoing pipex(4) packets will be delivered regardless on session's
`flags'. pppx(4) output has no PIPEX_SFLAGS_IP{,6}_FORWARD flags check,
so remove them from pppac(4) output too.
This allow us to make output lockless for pppoe sessions and cover very
small code sections within pipex_{pptp,l2tp}_output().
Index: sys/net/pipex.c
===================================================================
RCS file: /cvs/src/sys/net/pipex.c,v
retrieving revision 1.141
diff -u -p -r1.141 pipex.c
--- sys/net/pipex.c 26 Jun 2022 22:51:58 -0000 1.141
+++ sys/net/pipex.c 27 Jun 2022 08:57:38 -0000
@@ -767,9 +767,7 @@ pipex_ip_output(struct mbuf *m0, struct
/*
* Multicast packet is a idle packet and it's not TCP.
*/
- if ((session->flags & (PIPEX_SFLAGS_IP_FORWARD |
- PIPEX_SFLAGS_IP6_FORWARD)) == 0)
- goto drop;
+
/* reset idle timer */
if (session->timeout_sec != 0) {
is_idle = 0;
@@ -802,9 +800,6 @@ pipex_ip_output(struct mbuf *m0, struct
LIST_FOREACH(session_tmp, &pipex_session_list, session_list) {
if (session_tmp->ownersc != session->ownersc)
continue;
- if ((session->flags & (PIPEX_SFLAGS_IP_FORWARD |
- PIPEX_SFLAGS_IP6_FORWARD)) == 0)
- continue;
m = m_copym(m0, 0, M_COPYALL, M_NOWAIT);
if (m == NULL) {
counters_inc(session->stat_counters,
@@ -817,8 +812,6 @@ pipex_ip_output(struct mbuf *m0, struct
}
return;
-drop:
- m_freem(m0);
dropped:
counters_inc(session->stat_counters, pxc_oerrors);
}
