Remove PIPEXCSESSION pipex(4) ioctl(2) command from kernel and man page.

Long time ago pipex(4) session can't be deleted until both pipex(4)
input and output queues become empty. Dead sessions were linked to the
stack and the `ip_forward' flag was used to prevent packets forwarding.
npppd(8) marked such sessions by doing PIPEXCSESSION ioctl(2) call.

But since we started to unlink close session from the stack, this logic
became unnecessary. Also pipex(4) session could be closed just after
close request.

npppd(8) was the only userland program which did PIPEXCSESSION ioctl(2)
call, and we removed it week ago. It's time to remove the remains.

Now the `flags' member of 'pipex_session' structure became immutable.

ok yasuoka@

1 files changed, 2 insertions, 46 deletions

diff --git a/sys/net/pipex.c b/sys/net/pipex.c
index 2b43d9652a3..74c365745a1 100644
--- a/sys/net/pipex.c
+++ b/sys/net/pipex.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: pipex.c,v 1.144 2022/07/10 21:28:10 mvs Exp $ */
+/*	$OpenBSD: pipex.c,v 1.145 2022/07/12 08:58:53 mvs Exp $ */
 
 /*-
  * Copyright (c) 2009 Internet Initiative Japan Inc.
@@ -173,11 +173,6 @@ pipex_ioctl(void *ownersc, u_long cmd, caddr_t data)
 
 	NET_ASSERT_LOCKED();
 	switch (cmd) {
-	case PIPEXCSESSION:
-		ret = pipex_config_session(
-		    (struct pipex_session_config_req *)data, ownersc);
-		break;
-
 	case PIPEXGSTAT:
 		ret = pipex_get_stat((struct pipex_session_stat_req *)data,
 		    ownersc);
@@ -323,8 +318,6 @@ pipex_init_session(struct pipex_session **rsession,
 	session->ppp_flags = req->pr_ppp_flags;
 	session->ppp_id = req->pr_ppp_id;
 
-	session->flags |= PIPEX_SFLAGS_IP_FORWARD;
-
 	session->stat_counters = counters_alloc(pxc_ncounters);
 
 	session->ip_address.sin_family = AF_INET;
@@ -569,32 +562,6 @@ pipex_export_session_stats(struct pipex_session *session,
 }
 
 Static int
-pipex_config_session(struct pipex_session_config_req *req, void *ownersc)
-{
-	struct pipex_session *session;
-	int error = 0;
-
-	NET_ASSERT_LOCKED();
-
-	session = pipex_lookup_by_session_id(req->pcr_protocol,
-	    req->pcr_session_id);
-	if (session == NULL)
-		return (EINVAL);
-
-	if (session->ownersc == ownersc) {
-		if (req->pcr_ip_forward != 0)
-			session->flags |= PIPEX_SFLAGS_IP_FORWARD;
-		else
-			session->flags &= ~PIPEX_SFLAGS_IP_FORWARD;
-	} else
-		error = EINVAL;
-
-	pipex_rele_session(session);
-
-	return error;
-}
-
-Static int
 pipex_get_stat(struct pipex_session_stat_req *req, void *ownersc)
 {
 	struct pipex_session *session;
@@ -810,9 +777,7 @@ pipex_ip_output(struct mbuf *m0, struct pipex_session *session)
 		/*
 		 * 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;
@@ -850,9 +815,6 @@ pipex_ip_output(struct mbuf *m0, struct pipex_session *session)
 
 			if (session_tmp->ownersc != session->ownersc)
 				goto next;
-			if ((session->flags & (PIPEX_SFLAGS_IP_FORWARD |
-			    PIPEX_SFLAGS_IP6_FORWARD)) == 0)
-				goto next;
 
 			refcnt_take(&session_tmp->pxs_refcnt);
 			mtx_leave(&pipex_list_mtx);
@@ -878,8 +840,6 @@ next:
 	}
 
 	return;
-drop:
-	m_freem(m0);
 dropped:
 	counters_inc(session->stat_counters, pxc_oerrors);
 }
@@ -989,8 +949,6 @@ pipex_ppp_input(struct mbuf *m0, struct pipex_session *session, int decrypted)
 
 	switch (proto) {
 	case PPP_IP:
-		if ((session->flags & PIPEX_SFLAGS_IP_FORWARD) == 0)
-			goto drop;
 		if (!decrypted && pipex_session_is_mppe_required(session))
 			/*
 			 * if ip packet received when mppe
@@ -1001,8 +959,6 @@ pipex_ppp_input(struct mbuf *m0, struct pipex_session *session, int decrypted)
 		return;
 #ifdef INET6
 	case PPP_IPV6:
-		if ((session->flags & PIPEX_SFLAGS_IP6_FORWARD) == 0)
-			goto drop;
 		if (!decrypted && pipex_session_is_mppe_required(session))
 			/*
 			 * if ip packet received when mppe