Always accept TCP connection requests and identify to which neighbor

it belongs only _after_ receiving an Initialization message containing
the information we need. Before an Initialization message is received,
the TCP connection shouldn't be associated with any neighbor/adjacency.
Therefor refactor that part into a own module.
From Renato Westphal

9 files changed, 144 insertions, 113 deletions

diff --git a/usr.sbin/ldpd/address.c b/usr.sbin/ldpd/address.c
index 3cfdf0faba8..7fa2d3ae4dc 100644
--- a/usr.sbin/ldpd/address.c
+++ b/usr.sbin/ldpd/address.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: address.c,v 1.12 2013/06/04 00:41:18 claudio Exp $ */
+/*	$OpenBSD: address.c,v 1.13 2013/06/04 02:34:48 claudio Exp $ */
 
 /*
  * Copyright (c) 2009 Michele Marchetto <michele@openbsd.org>
@@ -72,7 +72,7 @@ send_address(struct nbr *nbr, struct if_addr *if_addr)
 
 	gen_address_list_tlv(buf, if_addr, size);
 
-	evbuf_enqueue(&nbr->wbuf, buf);
+	evbuf_enqueue(&nbr->tcp->wbuf, buf);
 	nbr_fsm(nbr, NBR_EVT_PDU_SENT);
 }
 
@@ -186,6 +186,6 @@ send_address_withdraw(struct nbr *nbr, struct if_addr *if_addr)
 
 	gen_address_list_tlv(buf, if_addr, size);
 
-	evbuf_enqueue(&nbr->wbuf, buf);
+	evbuf_enqueue(&nbr->tcp->wbuf, buf);
 	nbr_fsm(nbr, NBR_EVT_PDU_SENT);
 }
diff --git a/usr.sbin/ldpd/init.c b/usr.sbin/ldpd/init.c
index 90937841f53..26680dc9d24 100644
--- a/usr.sbin/ldpd/init.c
+++ b/usr.sbin/ldpd/init.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: init.c,v 1.11 2013/06/04 01:32:16 claudio Exp $ */
+/*	$OpenBSD: init.c,v 1.12 2013/06/04 02:34:48 claudio Exp $ */
 
 /*
  * Copyright (c) 2009 Michele Marchetto <michele@openbsd.org>
@@ -65,7 +65,7 @@ send_init(struct nbr *nbr)
 
 	gen_init_prms_tlv(buf, nbr, size);
 
-	evbuf_enqueue(&nbr->wbuf, buf);
+	evbuf_enqueue(&nbr->tcp->wbuf, buf);
 }
 
 int
diff --git a/usr.sbin/ldpd/keepalive.c b/usr.sbin/ldpd/keepalive.c
index 0207a983973..443697991cc 100644
--- a/usr.sbin/ldpd/keepalive.c
+++ b/usr.sbin/ldpd/keepalive.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: keepalive.c,v 1.9 2013/06/01 18:47:07 claudio Exp $ */
+/*	$OpenBSD: keepalive.c,v 1.10 2013/06/04 02:34:48 claudio Exp $ */
 
 /*
  * Copyright (c) 2009 Michele Marchetto <michele@openbsd.org>
@@ -54,7 +54,7 @@ send_keepalive(struct nbr *nbr)
 
 	gen_msg_tlv(buf, MSG_TYPE_KEEPALIVE, size);
 
-	evbuf_enqueue(&nbr->wbuf, buf);
+	evbuf_enqueue(&nbr->tcp->wbuf, buf);
 }
 
 int
diff --git a/usr.sbin/ldpd/labelmapping.c b/usr.sbin/ldpd/labelmapping.c
index f4fd3566f25..2ed93570578 100644
--- a/usr.sbin/ldpd/labelmapping.c
+++ b/usr.sbin/ldpd/labelmapping.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: labelmapping.c,v 1.23 2013/06/01 19:42:07 claudio Exp $ */
+/*	$OpenBSD: labelmapping.c,v 1.24 2013/06/04 02:34:48 claudio Exp $ */
 
 /*
  * Copyright (c) 2009 Michele Marchetto <michele@openbsd.org>
@@ -83,7 +83,7 @@ send_labelmapping(struct nbr *nbr)
 	ldp_hdr = ibuf_seek(buf, 0, sizeof(struct ldp_hdr));
 	ldp_hdr->length = htons(size);
 
-	evbuf_enqueue(&nbr->wbuf, buf);
+	evbuf_enqueue(&nbr->tcp->wbuf, buf);
 	nbr_fsm(nbr, NBR_EVT_PDU_SENT);
 }
 
@@ -184,7 +184,7 @@ send_labelrequest(struct nbr *nbr)
 	ldp_hdr = ibuf_seek(buf, 0, sizeof(struct ldp_hdr));
 	ldp_hdr->length = htons(size);
 
-	evbuf_enqueue(&nbr->wbuf, buf);
+	evbuf_enqueue(&nbr->tcp->wbuf, buf);
 	nbr_fsm(nbr, NBR_EVT_PDU_SENT);
 }
 
@@ -281,7 +281,7 @@ send_labelwithdraw(struct nbr *nbr)
 	ldp_hdr = ibuf_seek(buf, 0, sizeof(struct ldp_hdr));
 	ldp_hdr->length = htons(size);
 
-	evbuf_enqueue(&nbr->wbuf, buf);
+	evbuf_enqueue(&nbr->tcp->wbuf, buf);
 	nbr_fsm(nbr, NBR_EVT_PDU_SENT);
 }
 
@@ -414,7 +414,7 @@ send_labelrelease(struct nbr *nbr)
 	ldp_hdr = ibuf_seek(buf, 0, sizeof(struct ldp_hdr));
 	ldp_hdr->length = htons(size);
 
-	evbuf_enqueue(&nbr->wbuf, buf);
+	evbuf_enqueue(&nbr->tcp->wbuf, buf);
 	nbr_fsm(nbr, NBR_EVT_PDU_SENT);
 }
 
@@ -525,7 +525,7 @@ send_labelabortreq(struct nbr *nbr)
 
 	gen_msg_tlv(buf, MSG_TYPE_LABELABORTREQ, size);
 
-	evbuf_enqueue(&nbr->wbuf, buf);
+	evbuf_enqueue(&nbr->tcp->wbuf, buf);
 	nbr_fsm(nbr, NBR_EVT_PDU_SENT);
 }
 
diff --git a/usr.sbin/ldpd/ldpd.h b/usr.sbin/ldpd/ldpd.h
index c966f78ab40..b1a8d9d772e 100644
--- a/usr.sbin/ldpd/ldpd.h
+++ b/usr.sbin/ldpd/ldpd.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ldpd.h,v 1.41 2013/06/04 02:28:27 claudio Exp $ */
+/*	$OpenBSD: ldpd.h,v 1.42 2013/06/04 02:34:48 claudio Exp $ */
 
 /*
  * Copyright (c) 2009 Michele Marchetto <michele@openbsd.org>
@@ -153,6 +153,7 @@ enum iface_type {
 /* neighbor events */
 enum nbr_event {
 	NBR_EVT_NOTHING,
+	NBR_EVT_MATCH_ADJ,
 	NBR_EVT_CONNECT_UP,
 	NBR_EVT_CLOSE_SESSION,
 	NBR_EVT_INIT_RCVD,
diff --git a/usr.sbin/ldpd/ldpe.h b/usr.sbin/ldpd/ldpe.h
index e9f7255b04f..473ae4d54d8 100644
--- a/usr.sbin/ldpd/ldpe.h
+++ b/usr.sbin/ldpd/ldpe.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ldpe.h,v 1.26 2013/06/04 02:28:27 claudio Exp $ */
+/*	$OpenBSD: ldpe.h,v 1.27 2013/06/04 02:34:48 claudio Exp $ */
 
 /*
  * Copyright (c) 2004, 2005, 2008 Esben Norby <norby@openbsd.org>
@@ -48,10 +48,18 @@ struct adj {
 	struct in_addr		 addr;
 };
 
-struct nbr {
-	RB_ENTRY(nbr)		 id_tree, addr_tree, pid_tree;
+struct nbr;
+struct tcp_conn {
+	struct nbr		*nbr;
+	int			 fd;
+	struct ibuf_read	*rbuf;
 	struct evbuf		 wbuf;
 	struct event		 rev;
+};
+
+struct nbr {
+	RB_ENTRY(nbr)		 id_tree, pid_tree;
+	struct tcp_conn		*tcp;
 	LIST_HEAD(, adj)	 adj_list;	/* adjacencies */
 	struct event		 ev_connect;
 	struct event		 keepalive_timer;
@@ -67,15 +75,12 @@ struct nbr {
 	struct in_addr		 addr;
 	struct in_addr		 id;
 
-	struct ibuf_read	*rbuf;
-
 	time_t			 uptime;
 	u_int32_t		 peerid;	/* unique ID in DB */
 
 	int			 fd;
 	int			 state;
 	int			 idtimer_cnt;
-
 	u_int16_t		 keepalive;
 };
 
@@ -105,7 +110,8 @@ int	 recv_keepalive(struct nbr *, char *, u_int16_t);
 
 /* notification.c */
 void	 send_notification_nbr(struct nbr *, u_int32_t, u_int32_t, u_int32_t);
-struct ibuf	*send_notification(u_int32_t, u_int32_t, u_int32_t);
+void	 send_notification(u_int32_t, struct tcp_conn *, u_int32_t,
+	    u_int32_t);
 int	 recv_notification(struct nbr *, char *, u_int16_t);
 
 /* address.c */
@@ -176,7 +182,6 @@ void		 ldpe_adj_ctl(struct ctl_conn *);
 struct nbr	*nbr_new(struct in_addr, struct in_addr);
 void		 nbr_del(struct nbr *);
 
-struct nbr	*nbr_find_ip(u_int32_t);
 struct nbr	*nbr_find_ldpid(u_int32_t);
 struct nbr	*nbr_find_peerid(u_int32_t);
 
@@ -196,7 +201,6 @@ int	 nbr_pending_idtimer(struct nbr *);
 int	 nbr_pending_connect(struct nbr *);
 
 int	 nbr_establish_connection(struct nbr *);
-void	 nbr_act_connect_setup(struct nbr *);
 
 void			 nbr_mapping_add(struct nbr *, struct mapping_head *,
 			    struct map *);
@@ -217,6 +221,10 @@ int	 send_packet(int, struct iface *, void *, size_t, struct sockaddr_in *);
 void	 disc_recv_packet(int, short, void *);
 void	 session_accept(int, short, void *);
 
+struct tcp_conn *tcp_new(int, struct nbr *);
+void		 tcp_close(struct tcp_conn *);
+
+
 void	 session_read(int, short, void *);
 void	 session_write(int, short, void *);
 void	 session_close(struct nbr *);
diff --git a/usr.sbin/ldpd/neighbor.c b/usr.sbin/ldpd/neighbor.c
index f9ecb08b36b..b04628980f2 100644
--- a/usr.sbin/ldpd/neighbor.c
+++ b/usr.sbin/ldpd/neighbor.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: neighbor.c,v 1.36 2013/06/04 02:25:28 claudio Exp $ */
+/*	$OpenBSD: neighbor.c,v 1.37 2013/06/04 02:34:48 claudio Exp $ */
 
 /*
  * Copyright (c) 2009 Michele Marchetto <michele@openbsd.org>
@@ -46,15 +46,11 @@ void	nbr_send_labelmappings(struct nbr *);
 int	nbr_act_session_operational(struct nbr *);
 
 static __inline int nbr_id_compare(struct nbr *, struct nbr *);
-static __inline int nbr_addr_compare(struct nbr *, struct nbr *);
 static __inline int nbr_pid_compare(struct nbr *, struct nbr *);
 
 RB_HEAD(nbr_id_head, nbr);
 RB_PROTOTYPE(nbr_id_head, nbr, id_tree, nbr_id_compare)
 RB_GENERATE(nbr_id_head, nbr, id_tree, nbr_id_compare)
-RB_HEAD(nbr_addr_head, nbr);
-RB_PROTOTYPE(nbr_addr_head, nbr, addr_tree, nbr_addr_compare)
-RB_GENERATE(nbr_addr_head, nbr, addr_tree, nbr_addr_compare)
 RB_HEAD(nbr_pid_head, nbr);
 RB_PROTOTYPE(nbr_pid_head, nbr, pid_tree, nbr_pid_compare)
 RB_GENERATE(nbr_pid_head, nbr, pid_tree, nbr_pid_compare)
@@ -66,19 +62,12 @@ nbr_id_compare(struct nbr *a, struct nbr *b)
 }
 
 static __inline int
-nbr_addr_compare(struct nbr *a, struct nbr *b)
-{
-	return (ntohl(a->addr.s_addr) - ntohl(b->addr.s_addr));
-}
-
-static __inline int
 nbr_pid_compare(struct nbr *a, struct nbr *b)
 {
 	return (a->peerid - b->peerid);
 }
 
 struct nbr_id_head nbrs_by_id = RB_INITIALIZER(&nbrs_by_id);
-struct nbr_addr_head nbrs_by_addr = RB_INITIALIZER(&nbrs_by_addr);
 struct nbr_pid_head nbrs_by_pid = RB_INITIALIZER(&nbrs_by_pid);
 
 u_int32_t	peercnt = NBR_CNTSTART;
@@ -92,11 +81,12 @@ struct {
 	int		new_state;
 } nbr_fsm_tbl[] = {
     /* current state	event that happened	action to take		resulting state */
-    {NBR_STA_PRESENT,	NBR_EVT_CONNECT_UP,	NBR_ACT_CONNECT_SETUP,	NBR_STA_INITIAL},
 /* Passive Role */
+    {NBR_STA_PRESENT,	NBR_EVT_MATCH_ADJ,	NBR_ACT_NOTHING,	NBR_STA_INITIAL},
     {NBR_STA_INITIAL,	NBR_EVT_INIT_RCVD,	NBR_ACT_PASSIVE_INIT,	NBR_STA_OPENREC},
     {NBR_STA_OPENREC,	NBR_EVT_KEEPALIVE_RCVD,	NBR_ACT_SESSION_EST,	NBR_STA_OPER},
 /* Active Role */
+    {NBR_STA_PRESENT,	NBR_EVT_CONNECT_UP,	NBR_ACT_CONNECT_SETUP,	NBR_STA_INITIAL},
     {NBR_STA_INITIAL,	NBR_EVT_INIT_SENT,	NBR_ACT_NOTHING,	NBR_STA_OPENSENT},
     {NBR_STA_OPENSENT,	NBR_EVT_INIT_RCVD,	NBR_ACT_KEEPALIVE_SEND,	NBR_STA_OPENREC},
 /* Session Maintenance */
@@ -110,6 +100,7 @@ struct {
 
 const char * const nbr_event_names[] = {
 	"NOTHING",
+	"ADJACENCY MATCHED",
 	"CONNECTION UP",
 	"SESSION CLOSE",
 	"INIT RECEIVED",
@@ -187,13 +178,11 @@ nbr_fsm(struct nbr *nbr, enum nbr_event event)
 		nbr_send_labelmappings(nbr);
 		break;
 	case NBR_ACT_CONNECT_SETUP:
-		nbr_act_connect_setup(nbr);
+		nbr->tcp = tcp_new(nbr->fd, nbr);
 
-		if (nbr_session_active_role(nbr)) {
-			/* trigger next state */
-			send_init(nbr);
-			nbr_fsm(nbr, NBR_EVT_INIT_SENT);
-		}
+		/* trigger next state */
+		send_init(nbr);
+		nbr_fsm(nbr, NBR_EVT_INIT_SENT);
 		break;
 	case NBR_ACT_PASSIVE_INIT:
 		send_init(nbr);
@@ -225,8 +214,6 @@ nbr_new(struct in_addr id, struct in_addr addr)
 
 	if ((nbr = calloc(1, sizeof(*nbr))) == NULL)
 		fatal("nbr_new");
-	if ((nbr->rbuf = calloc(1, sizeof(struct ibuf_read))) == NULL)
-		fatal("nbr_new");
 
 	nbr->state = NBR_STA_PRESENT;
 	nbr->id.s_addr = id.s_addr;
@@ -239,8 +226,6 @@ nbr_new(struct in_addr id, struct in_addr addr)
 
 	if (RB_INSERT(nbr_pid_head, &nbrs_by_pid, nbr) != NULL)
 		fatalx("nbr_new: RB_INSERT(nbrs_by_pid) failed");
-	if (RB_INSERT(nbr_addr_head, &nbrs_by_addr, nbr) != NULL)
-		fatalx("nbr_new: RB_INSERT(nbrs_by_addr) failed");
 	if (RB_INSERT(nbr_id_head, &nbrs_by_id, nbr) != NULL)
 		fatalx("nbr_new: RB_INSERT(nbrs_by_id) failed");
 
@@ -278,10 +263,8 @@ nbr_del(struct nbr *nbr)
 	nbr_mapping_list_clr(nbr, &nbr->abortreq_list);
 
 	RB_REMOVE(nbr_pid_head, &nbrs_by_pid, nbr);
-	RB_REMOVE(nbr_addr_head, &nbrs_by_addr, nbr);
 	RB_REMOVE(nbr_id_head, &nbrs_by_id, nbr);
 
-	free(nbr->rbuf);
 	free(nbr);
 }
 
@@ -294,14 +277,6 @@ nbr_find_peerid(u_int32_t peerid)
 }
 
 struct nbr *
-nbr_find_ip(u_int32_t addr)
-{
-	struct nbr	n;
-	n.addr.s_addr = addr;
-	return (RB_FIND(nbr_addr_head, &nbrs_by_addr, &n));
-}
-
-struct nbr *
 nbr_find_ldpid(u_int32_t rtr_id)
 {
 	struct nbr	n;
@@ -539,14 +514,6 @@ nbr_establish_connection(struct nbr *nbr)
 	return (0);
 }
 
-void
-nbr_act_connect_setup(struct nbr *nbr)
-{
-	evbuf_init(&nbr->wbuf, nbr->fd, session_write, nbr);
-	event_set(&nbr->rev, nbr->fd, EV_READ | EV_PERSIST, session_read, nbr);
-	event_add(&nbr->rev, NULL);
-}
-
 int
 nbr_act_session_operational(struct nbr *nbr)
 {
@@ -646,7 +613,7 @@ ldpe_nbr_ctl(struct ctl_conn *c)
 	struct nbr	*nbr;
 	struct ctl_nbr	*nctl;
 
-	RB_FOREACH(nbr, nbr_addr_head, &nbrs_by_addr) {
+	RB_FOREACH(nbr, nbr_pid_head, &nbrs_by_pid) {
 		nctl = nbr_to_ctl(nbr);
 		imsg_compose_event(&c->iev, IMSG_CTL_SHOW_NBR, 0, 0, -1, nctl,
 		    sizeof(struct ctl_nbr));
diff --git a/usr.sbin/ldpd/notification.c b/usr.sbin/ldpd/notification.c
index be57dd1acc4..f3e62868767 100644
--- a/usr.sbin/ldpd/notification.c
+++ b/usr.sbin/ldpd/notification.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: notification.c,v 1.13 2013/06/04 01:32:16 claudio Exp $ */
+/*	$OpenBSD: notification.c,v 1.14 2013/06/04 02:34:48 claudio Exp $ */
 
 /*
  * Copyright (c) 2009 Michele Marchetto <michele@openbsd.org>
@@ -43,15 +43,13 @@ void
 send_notification_nbr(struct nbr *nbr, u_int32_t status, u_int32_t msgid,
     u_int32_t type)
 {
-	struct ibuf	*buf;
-
-	buf = send_notification(status, msgid, type);
-	evbuf_enqueue(&nbr->wbuf, buf);
+	send_notification(status, nbr->tcp, msgid, type);
 	nbr_fsm(nbr, NBR_EVT_PDU_SENT);
 }
 
-struct ibuf *
-send_notification(u_int32_t status, u_int32_t msgid, u_int32_t type)
+void
+send_notification(u_int32_t status, struct tcp_conn *tcp, u_int32_t msgid,
+    u_int32_t type)
 {
 	struct ibuf	*buf;
 	u_int16_t	 size;
@@ -71,7 +69,7 @@ send_notification(u_int32_t status, u_int32_t msgid, u_int32_t type)
 
 	gen_status_tlv(buf, status, msgid, type);
 
-	return (buf);
+	evbuf_enqueue(&tcp->wbuf, buf);
 }
 
 int
diff --git a/usr.sbin/ldpd/packet.c b/usr.sbin/ldpd/packet.c
index 98637b8d769..f1e90776559 100644
--- a/usr.sbin/ldpd/packet.c
+++ b/usr.sbin/ldpd/packet.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: packet.c,v 1.26 2013/06/04 02:25:28 claudio Exp $ */
+/*	$OpenBSD: packet.c,v 1.27 2013/06/04 02:34:48 claudio Exp $ */
 
 /*
  * Copyright (c) 2009 Michele Marchetto <michele@openbsd.org>
@@ -227,11 +227,41 @@ disc_find_iface(unsigned int ifindex, struct in_addr src)
 	return (NULL);
 }
 
+struct tcp_conn *
+tcp_new(int fd, struct nbr *nbr)
+{
+	struct tcp_conn *tcp;
+
+	if ((tcp = calloc(1, sizeof(*tcp))) == NULL)
+		fatal("tcp_new");
+	if ((tcp->rbuf = calloc(1, sizeof(struct ibuf_read))) == NULL)
+		fatal("tcp_new");
+
+	if (nbr)
+		tcp->nbr = nbr;
+
+	tcp->fd = fd;
+	evbuf_init(&tcp->wbuf, tcp->fd, session_write, tcp);
+	event_set(&tcp->rev, tcp->fd, EV_READ | EV_PERSIST, session_read, tcp);
+	event_add(&tcp->rev, NULL);
+
+	return (tcp);
+}
+
+void
+tcp_close(struct tcp_conn *tcp)
+{
+	evbuf_clear(&tcp->wbuf);
+	event_del(&tcp->rev);
+	close(tcp->fd);
+	free(tcp->rbuf);
+	free(tcp);
+}
+
 void
 session_accept(int fd, short event, void *bula)
 {
 	struct sockaddr_in	 src;
-	struct nbr		*nbr = NULL;
 	int			 newfd;
 	socklen_t		 len = sizeof(src);
 
@@ -255,28 +285,14 @@ session_accept(int fd, short event, void *bula)
 
 	session_socket_blockmode(newfd, BM_NONBLOCK);
 
-	nbr = nbr_find_ip(src.sin_addr.s_addr);
-	if (nbr == NULL) {
-		struct ibuf	*buf;
-		/* If there is no neighbor matching there is no
-		   Hello adjacency: try to send notification */
-		log_warnx("Connection attempt from unknown neighbor %s: %s",
-		    inet_ntoa(src.sin_addr), "NO HELLO");
-		buf = send_notification(S_NO_HELLO, 0, 0);
-		write(newfd, buf->buf, buf->wpos);
-		ibuf_free(buf);
-		close(newfd);
-		return;
-	}
-
-	nbr->fd = newfd;
-	nbr_fsm(nbr, NBR_EVT_CONNECT_UP);
+	tcp_new(newfd, NULL);
 }
 
 void
 session_read(int fd, short event, void *arg)
 {
-	struct nbr	*nbr = arg;
+	struct tcp_conn	*tcp = arg;
+	struct nbr	*nbr = tcp->nbr;
 	struct ldp_hdr	*ldp_hdr;
 	struct ldp_msg	*ldp_msg;
 	char		*buf, *pdu;
@@ -289,11 +305,14 @@ session_read(int fd, short event, void *arg)
 		return;
 	}
 
-	if ((n = read(fd, nbr->rbuf->buf + nbr->rbuf->wpos,
-	    sizeof(nbr->rbuf->buf) - nbr->rbuf->wpos)) == -1) {
+	if ((n = read(fd, tcp->rbuf->buf + tcp->rbuf->wpos,
+	    sizeof(tcp->rbuf->buf) - tcp->rbuf->wpos)) == -1) {
 		if (errno != EINTR && errno != EAGAIN) {
 			log_warn("session_read: read error");
-			nbr_fsm(nbr, NBR_EVT_CLOSE_SESSION);
+			if (nbr)
+				nbr_fsm(nbr, NBR_EVT_CLOSE_SESSION);
+			else
+				tcp_close(tcp);
 			return;
 		}
 		/* retry read */
@@ -302,32 +321,68 @@ session_read(int fd, short event, void *arg)
 	if (n == 0) {
 		/* connection closed */
 		log_debug("session_read: connection closed by remote end");
-		nbr_fsm(nbr, NBR_EVT_CLOSE_SESSION);
+		if (nbr)
+			nbr_fsm(nbr, NBR_EVT_CLOSE_SESSION);
+		else
+			tcp_close(tcp);
 		return;
 	}
-	nbr->rbuf->wpos += n;
+	tcp->rbuf->wpos += n;
 
-	while ((len = session_get_pdu(nbr->rbuf, &buf)) > 0) {
+	while ((len = session_get_pdu(tcp->rbuf, &buf)) > 0) {
 		pdu = buf;
 		ldp_hdr = (struct ldp_hdr *)pdu;
 		if (ntohs(ldp_hdr->version) != LDP_VERSION) {
-			session_shutdown(nbr, S_BAD_PROTO_VER, 0, 0);
+			if (nbr)
+				session_shutdown(nbr, S_BAD_PROTO_VER, 0, 0);
+			else {
+				send_notification(S_BAD_PROTO_VER, tcp, 0, 0);
+				msgbuf_write(&tcp->wbuf.wbuf);
+				tcp_close(tcp);
+			}
 			free(buf);
 			return;
 		}
 
 		pdu_len = ntohs(ldp_hdr->length);
 		if (pdu_len < LDP_HDR_SIZE || pdu_len > LDP_MAX_LEN) {
-			session_shutdown(nbr, S_BAD_MSG_LEN, 0, 0);
+			if (nbr)
+				session_shutdown(nbr, S_BAD_MSG_LEN, 0, 0);
+			else {
+				send_notification(S_BAD_MSG_LEN, tcp, 0, 0);
+				msgbuf_write(&tcp->wbuf.wbuf);
+				tcp_close(tcp);
+			}
 			free(buf);
 			return;
 		}
 
-		if (ldp_hdr->lsr_id != nbr->id.s_addr ||
-		    ldp_hdr->lspace_id != 0) {
-			session_shutdown(nbr, S_BAD_LDP_ID, 0, 0);
-			free(buf);
-			return;
+		if (nbr) {
+			if (ldp_hdr->lsr_id != nbr->id.s_addr ||
+			    ldp_hdr->lspace_id != 0) {
+				session_shutdown(nbr, S_BAD_LDP_ID, 0, 0);
+				free(buf);
+				return;
+			}
+		} else {
+			nbr = nbr_find_ldpid(ldp_hdr->lsr_id);
+			if (!nbr) {
+				send_notification(S_NO_HELLO, tcp, 0, 0);
+				msgbuf_write(&tcp->wbuf.wbuf);
+				tcp_close(tcp);
+				free(buf);
+				return;
+			}
+			/* handle duplicate SYNs */
+			if (nbr->tcp) {
+				tcp_close(tcp);
+				free(buf);
+				return;
+			}
+
+			nbr->tcp = tcp;
+			tcp->nbr = nbr;
+			nbr_fsm(nbr, NBR_EVT_MATCH_ADJ);
 		}
 
 		pdu += LDP_HDR_SIZE;
@@ -442,15 +497,18 @@ session_read(int fd, short event, void *arg)
 void
 session_write(int fd, short event, void *arg)
 {
-	struct nbr *nbr = arg;
+	struct tcp_conn *tcp = arg;
+	struct nbr *nbr = tcp->nbr;
 
 	if (event & EV_WRITE) {
-		if (msgbuf_write(&nbr->wbuf.wbuf) == -1)
-			nbr_fsm(nbr, NBR_EVT_CLOSE_SESSION);
+		if (msgbuf_write(&tcp->wbuf.wbuf) == -1) {
+			if (nbr)
+				nbr_fsm(nbr, NBR_EVT_CLOSE_SESSION);
+		}
 	} else
 		log_debug("session_write: spurious event");
 
-	evbuf_event_add(&nbr->wbuf);
+	evbuf_event_add(&tcp->wbuf);
 }
 
 void
@@ -463,7 +521,7 @@ session_shutdown(struct nbr *nbr, u_int32_t status, u_int32_t msgid,
 	send_notification_nbr(nbr, status, msgid, type);
 
 	/* try to flush write buffer, if it fails tough shit */
-	msgbuf_write(&nbr->wbuf.wbuf);
+	msgbuf_write(&nbr->tcp->wbuf.wbuf);
 
 	nbr_fsm(nbr, NBR_EVT_CLOSE_SESSION);
 }
@@ -474,13 +532,12 @@ session_close(struct nbr *nbr)
 	log_debug("session_close: closing session with nbr ID %s",
 	    inet_ntoa(nbr->id));
 
-	evbuf_clear(&nbr->wbuf);
-	event_del(&nbr->rev);
+	tcp_close(nbr->tcp);
+	nbr->tcp = NULL;
 
 	nbr_stop_ktimer(nbr);
 	nbr_stop_ktimeout(nbr);
 
-	close(nbr->fd);
 	accept_unpause();
 }