From d16fa20132ea6d21b9bd26cc09246c12134ba6ee Mon Sep 17 00:00:00 2001
From: Sepherosa Ziehau <sephe@dragonflybsd.org>
Date: Sat, 31 Jan 2009 12:07:32 +0800
Subject: [PATCH] rtsock: Fix !SO_USELOOPBACK support in route_output()

Old BSD code assumes that rts_input() is synchronous, so clear/set
sp_family could be used to skip the current rawcb.  However, our
rts_input() is asynchronous, thus the clear/set sp_family trick no
longer takes any effect.

Reimplement the rawcb skipping in the following way:
- Record the address of rawcb to be skipped in netmsg.
- Extend raw_input() interface to accept a 'skip' argument.  At the
  beginning of the rawcb list iteration, check the address of the
  current rawcb against the 'skip'.
---
 sys/net/raw_cb.h     |  5 +++--
 sys/net/raw_usrreq.c |  7 +++++--
 sys/net/rtsock.c     | 27 +++++++++++++++++++--------
 3 files changed, 27 insertions(+), 12 deletions(-)

diff --git a/sys/net/raw_cb.h b/sys/net/raw_cb.h
index 2e67590295..50fc11305f 100644
--- a/sys/net/raw_cb.h
+++ b/sys/net/raw_cb.h
@@ -79,8 +79,9 @@ void	 raw_ctlinput (int, struct sockaddr *, void *);
 void	 raw_detach (struct rawcb *);
 void	 raw_disconnect (struct rawcb *);
 void	 raw_init (void);
-void	 raw_input (struct mbuf *, struct sockproto *,
-		    const struct sockaddr *, const struct sockaddr *);
+void	 raw_input (struct mbuf *, const struct sockproto *,
+		    const struct sockaddr *, const struct sockaddr *,
+		    const struct rawcb *);
 
 extern	struct pr_usrreqs raw_usrreqs;
 #endif
diff --git a/sys/net/raw_usrreq.c b/sys/net/raw_usrreq.c
index fb38a7654f..3e98646d44 100644
--- a/sys/net/raw_usrreq.c
+++ b/sys/net/raw_usrreq.c
@@ -68,8 +68,9 @@ raw_init(void)
  * Most other raw protocol interface functions are also serialized XXX.
  */
 void
-raw_input(struct mbuf *m0, struct sockproto *proto, const struct sockaddr *src,
-	  const struct sockaddr *dst)
+raw_input(struct mbuf *m0, const struct sockproto *proto,
+	  const struct sockaddr *src, const struct sockaddr *dst,
+	  const struct rawcb *skip)
 {
 	struct rawcb *rp;
 	struct mbuf *m = m0;
@@ -77,6 +78,8 @@ raw_input(struct mbuf *m0, struct sockproto *proto, const struct sockaddr *src,
 
 	last = NULL;
 	LIST_FOREACH(rp, &rawcb_list, list) {
+		if (rp == skip)
+			continue;
 		if (rp->rcb_proto.sp_family != proto->sp_family)
 			continue;
 		if (rp->rcb_proto.sp_protocol  &&
diff --git a/sys/net/rtsock.c b/sys/net/rtsock.c
index 3b95ed0f31..e2f2160113 100644
--- a/sys/net/rtsock.c
+++ b/sys/net/rtsock.c
@@ -350,31 +350,46 @@ rts_input_handler(struct netmsg *msg)
 	struct netmsg_packet *pmsg;
 	struct mbuf *m;
 	sa_family_t family;
+	struct rawcb *skip;
 
 	pmsg = (void *)msg;
-	m = pmsg->nm_packet;
 	family = pmsg->nm_netmsg.nm_lmsg.u.ms_result;
 	route_proto.sp_family = PF_ROUTE;
 	route_proto.sp_protocol = family;
 
-	raw_input(m, &route_proto, &route_src, &route_dst);
+	m = pmsg->nm_packet;
+	M_ASSERTPKTHDR(m);
+
+	skip = m->m_pkthdr.header;
+	m->m_pkthdr.header = NULL;
+
+	raw_input(m, &route_proto, &route_src, &route_dst, skip);
 }
 
 static void
-rts_input(struct mbuf *m, sa_family_t family)
+rts_input_skip(struct mbuf *m, sa_family_t family, struct rawcb *skip)
 {
 	struct netmsg_packet *pmsg;
 	lwkt_port_t port;
 
+	M_ASSERTPKTHDR(m);
+
 	port = cpu0_soport(NULL, NULL, NULL, 0);
 	pmsg = &m->m_hdr.mh_netmsg;
 	netmsg_init(&pmsg->nm_netmsg, &netisr_apanic_rport, 
 		    0, rts_input_handler);
 	pmsg->nm_packet = m;
 	pmsg->nm_netmsg.nm_lmsg.u.ms_result = family;
+	m->m_pkthdr.header = skip; /* XXX steal field in pkthdr */
 	lwkt_sendmsg(port, &pmsg->nm_netmsg.nm_lmsg);
 }
 
+static __inline void
+rts_input(struct mbuf *m, sa_family_t family)
+{
+	rts_input_skip(m, family, NULL);
+}
+
 static void *
 reallocbuf(void *ptr, size_t len, size_t olen)
 {
@@ -594,12 +609,8 @@ flush:
 			m_adj(m, rtm->rtm_msglen - m->m_pkthdr.len);
 		kfree(rtm, M_RTABLE);
 	}
-	if (rp != NULL)
-		rp->rcb_proto.sp_family = 0; /* Avoid us */
 	if (m != NULL)
-		rts_input(m, familyof(rtinfo.rti_dst));
-	if (rp != NULL)
-		rp->rcb_proto.sp_family = PF_ROUTE;
+		rts_input_skip(m, familyof(rtinfo.rti_dst), rp);
 	return (error);
 }
 
-- 
2.41.0