Implement RFC 5561 (LDP Capabilities).

This patch per-se doesn't introduce any useful functionality, but prepares
the ground for new enhancements to ldpd (i.e. implementation of new RFCs
that make use of LDP capabilities).

9 files changed, 262 insertions, 30 deletions

diff --git a/usr.sbin/ldpd/init.c b/usr.sbin/ldpd/init.c
index 721a6dfe298..ae1513720f1 100644
--- a/usr.sbin/ldpd/init.c
+++ b/usr.sbin/ldpd/init.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: init.c,v 1.34 2017/03/03 23:44:35 renato Exp $ */
+/*	$OpenBSD: init.c,v 1.35 2017/03/04 00:06:10 renato Exp $ */
 
 /*
  * Copyright (c) 2009 Michele Marchetto <michele@openbsd.org>
@@ -25,6 +25,7 @@
 #include "log.h"
 
 static int	gen_init_prms_tlv(struct ibuf *, struct nbr *);
+static int	gen_cap_dynamic_tlv(struct ibuf *);
 
 void
 send_init(struct nbr *nbr)
@@ -35,15 +36,16 @@ send_init(struct nbr *nbr)
 
 	log_debug("%s: lsr-id %s", __func__, inet_ntoa(nbr->id));
 
-	size = LDP_HDR_SIZE + LDP_MSG_SIZE + SESS_PRMS_SIZE;
+	size = LDP_HDR_SIZE + LDP_MSG_SIZE + SESS_PRMS_SIZE +
+	    CAP_TLV_DYNAMIC_SIZE;
 	if ((buf = ibuf_open(size)) == NULL)
 		fatal(__func__);
 
 	err |= gen_ldp_hdr(buf, size);
 	size -= LDP_HDR_SIZE;
 	err |= gen_msg_hdr(buf, MSG_TYPE_INIT, size);
-	size -= LDP_MSG_SIZE;
 	err |= gen_init_prms_tlv(buf, nbr);
+	err |= gen_cap_dynamic_tlv(buf);
 	if (err) {
 		ibuf_free(buf);
 		return;
@@ -58,6 +60,7 @@ recv_init(struct nbr *nbr, char *buf, uint16_t len)
 	struct ldp_msg		msg;
 	struct sess_prms_tlv	sess;
 	uint16_t		max_pdu_len;
+	int			caps_rcvd = 0;
 
 	log_debug("%s: lsr-id %s", __func__, inet_ntoa(nbr->id));
 
@@ -94,6 +97,7 @@ recv_init(struct nbr *nbr, char *buf, uint16_t len)
 	/* Optional Parameters */
 	while (len > 0) {
 		struct tlv 	tlv;
+		uint16_t	tlv_type;
 		uint16_t	tlv_len;
 
 		if (len < sizeof(tlv)) {
@@ -102,6 +106,7 @@ recv_init(struct nbr *nbr, char *buf, uint16_t len)
 		}
 
 		memcpy(&tlv, buf, TLV_HDR_SIZE);
+		tlv_type = ntohs(tlv.type);
 		tlv_len = ntohs(tlv.length);
 		if (tlv_len + TLV_HDR_SIZE > len) {
 			session_shutdown(nbr, S_BAD_TLV_LEN, msg.id, msg.type);
@@ -110,17 +115,42 @@ recv_init(struct nbr *nbr, char *buf, uint16_t len)
 		buf += TLV_HDR_SIZE;
 		len -= TLV_HDR_SIZE;
 
-		switch (ntohs(tlv.type)) {
+		/*
+		 * RFC 5561 - Section 6:
+		 * "The S-bit of a Capability Parameter in an Initialization
+		 * message MUST be 1 and SHOULD be ignored on receipt".
+		 */
+		switch (tlv_type) {
 		case TLV_TYPE_ATMSESSIONPAR:
 			session_shutdown(nbr, S_BAD_TLV_VAL, msg.id, msg.type);
 			return (-1);
 		case TLV_TYPE_FRSESSION:
 			session_shutdown(nbr, S_BAD_TLV_VAL, msg.id, msg.type);
 			return (-1);
+		case TLV_TYPE_DYNAMIC_CAP:
+			if (tlv_len != CAP_TLV_DYNAMIC_LEN) {
+				session_shutdown(nbr, S_BAD_TLV_LEN, msg.id,
+				    msg.type);
+				return (-1);
+			}
+
+			if (caps_rcvd & F_CAP_TLV_RCVD_DYNAMIC) {
+				session_shutdown(nbr, S_BAD_TLV_VAL, msg.id,
+				    msg.type);
+				return (-1);
+			}
+			caps_rcvd |= F_CAP_TLV_RCVD_DYNAMIC;
+
+			nbr->flags |= F_NBR_CAP_DYNAMIC;
+
+			log_debug("%s: lsr-id %s announced the Dynamic "
+			    "Capability Announcement capability", __func__,
+			    inet_ntoa(nbr->id));
+			break;
 		default:
 			if (!(ntohs(tlv.type) & UNKNOWN_FLAG))
-				send_notification(nbr->tcp, S_UNKNOWN_TLV,
-				    msg.id, msg.type);
+				send_notification_rtlvs(nbr, S_UNSSUPORTDCAP,
+				    msg.id, msg.type, tlv_type, tlv_len, buf);
 			/* ignore unknown tlv */
 			break;
 		}
@@ -146,6 +176,104 @@ recv_init(struct nbr *nbr, char *buf, uint16_t len)
 	return (0);
 }
 
+void
+send_capability(struct nbr *nbr, uint16_t capability, int enable)
+{
+	struct ibuf		*buf;
+	uint16_t		 size;
+	int			 err = 0;
+
+	log_debug("%s: lsr-id %s", __func__, inet_ntoa(nbr->id));
+
+	size = LDP_HDR_SIZE + LDP_MSG_SIZE + CAP_TLV_DYNAMIC_SIZE;
+	if ((buf = ibuf_open(size)) == NULL)
+		fatal(__func__);
+
+	err |= gen_ldp_hdr(buf, size);
+	size -= LDP_HDR_SIZE;
+	err |= gen_msg_hdr(buf, MSG_TYPE_CAPABILITY, size);
+
+	switch (capability) {
+	case TLV_TYPE_DYNAMIC_CAP:
+		/*
+		 * RFC 5561 - Section 9:
+		 * "An LDP speaker MUST NOT include the Dynamic Capability
+		 * Announcement Parameter in Capability messages sent to
+		 * its peers".
+		 */
+		/* FALLTHROUGH */
+	default:
+		fatalx("send_capability: unsupported capability");
+	}
+
+	if (err) {
+		ibuf_free(buf);
+		return;
+	}
+
+	evbuf_enqueue(&nbr->tcp->wbuf, buf);
+	nbr_fsm(nbr, NBR_EVT_PDU_SENT);
+}
+
+int
+recv_capability(struct nbr *nbr, char *buf, uint16_t len)
+{
+	struct ldp_msg	 msg;
+
+	log_debug("%s: lsr-id %s", __func__, inet_ntoa(nbr->id));
+
+	memcpy(&msg, buf, sizeof(msg));
+	buf += LDP_MSG_SIZE;
+	len -= LDP_MSG_SIZE;
+
+	/* Optional Parameters */
+	while (len > 0) {
+		struct tlv 	 tlv;
+		uint16_t	 tlv_type;
+		uint16_t	 tlv_len;
+
+		if (len < sizeof(tlv)) {
+			session_shutdown(nbr, S_BAD_TLV_LEN, msg.id, msg.type);
+			return (-1);
+		}
+
+		memcpy(&tlv, buf, TLV_HDR_SIZE);
+		tlv_type = ntohs(tlv.type);
+		tlv_len = ntohs(tlv.length);
+		if (tlv_len + TLV_HDR_SIZE > len) {
+			session_shutdown(nbr, S_BAD_TLV_LEN, msg.id, msg.type);
+			return (-1);
+		}
+		buf += TLV_HDR_SIZE;
+		len -= TLV_HDR_SIZE;
+
+		switch (tlv_type) {
+		case TLV_TYPE_DYNAMIC_CAP:
+			/*
+		 	 * RFC 5561 - Section 9:
+			 * "An LDP speaker that receives a Capability message
+			 * from a peer that includes the Dynamic Capability
+			 * Announcement Parameter SHOULD silently ignore the
+			 * parameter and process any other Capability Parameters
+			 * in the message".
+			 */
+			/* FALLTHROUGH */
+		default:
+			if (!(ntohs(tlv.type) & UNKNOWN_FLAG))
+				send_notification_rtlvs(nbr, S_UNSSUPORTDCAP,
+				    msg.id, msg.type, tlv_type, tlv_len, buf);
+			/* ignore unknown tlv */
+			break;
+		}
+		buf += tlv_len;
+		len -= tlv_len;
+	}
+
+	nbr_fsm(nbr, NBR_EVT_PDU_RCVD);
+
+	return (0);
+}
+
 static int
 gen_init_prms_tlv(struct ibuf *buf, struct nbr *nbr)
 {
@@ -164,3 +292,17 @@ gen_init_prms_tlv(struct ibuf *buf, struct nbr *nbr)
 
 	return (ibuf_add(buf, &parms, SESS_PRMS_SIZE));
 }
+
+static int
+gen_cap_dynamic_tlv(struct ibuf *buf)
+{
+	struct capability_tlv	cap;
+
+	memset(&cap, 0, sizeof(cap));
+	cap.type = htons(TLV_TYPE_DYNAMIC_CAP);
+	cap.length = htons(CAP_TLV_DYNAMIC_LEN);
+	/* the S-bit is always 1 for the Dynamic Capability Announcement */
+	cap.reserved = STATE_BIT;
+
+	return (ibuf_add(buf, &cap, CAP_TLV_DYNAMIC_SIZE));
+}
diff --git a/usr.sbin/ldpd/labelmapping.c b/usr.sbin/ldpd/labelmapping.c
index 964cc44286e..580d3072452 100644
--- a/usr.sbin/ldpd/labelmapping.c
+++ b/usr.sbin/ldpd/labelmapping.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: labelmapping.c,v 1.64 2017/03/03 23:50:45 renato Exp $ */
+/*	$OpenBSD: labelmapping.c,v 1.65 2017/03/04 00:06:10 renato Exp $ */
 
 /*
  * Copyright (c) 2014, 2015 Renato Westphal <renato@openbsd.org>
@@ -241,6 +241,7 @@ recv_labelmessage(struct nbr *nbr, char *buf, uint16_t len, uint16_t type)
 	/* Optional Parameters */
 	while (len > 0) {
 		struct tlv 	tlv;
+		uint16_t	tlv_type;
 		uint16_t	tlv_len;
 		uint32_t	reqbuf, labelbuf, statusbuf;
 
@@ -250,6 +251,7 @@ recv_labelmessage(struct nbr *nbr, char *buf, uint16_t len, uint16_t type)
 		}
 
 		memcpy(&tlv, buf, TLV_HDR_SIZE);
+		tlv_type = ntohs(tlv.type);
 		tlv_len = ntohs(tlv.length);
 		if (tlv_len + TLV_HDR_SIZE > len) {
 			session_shutdown(nbr, S_BAD_TLV_LEN, msg.id, msg.type);
@@ -258,7 +260,7 @@ recv_labelmessage(struct nbr *nbr, char *buf, uint16_t len, uint16_t type)
 		buf += TLV_HDR_SIZE;
 		len -= TLV_HDR_SIZE;
 
-		switch (ntohs(tlv.type)) {
+		switch (tlv_type) {
 		case TLV_TYPE_LABELREQUEST:
 			switch (type) {
 			case MSG_TYPE_LABELMAPPING:
@@ -343,8 +345,8 @@ recv_labelmessage(struct nbr *nbr, char *buf, uint16_t len, uint16_t type)
 			break;
 		default:
 			if (!(ntohs(tlv.type) & UNKNOWN_FLAG))
-				send_notification(nbr->tcp, S_UNKNOWN_TLV,
-				    msg.id, msg.type);
+				send_notification_rtlvs(nbr, S_UNKNOWN_TLV,
+				    msg.id, msg.type, tlv_type, tlv_len, buf);
 			/* ignore unknown tlv */
 			break;
 		}
diff --git a/usr.sbin/ldpd/ldp.h b/usr.sbin/ldpd/ldp.h
index e8c007a9c08..dd00af9eb76 100644
--- a/usr.sbin/ldpd/ldp.h
+++ b/usr.sbin/ldpd/ldp.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ldp.h,v 1.37 2017/03/03 23:56:54 renato Exp $ */
+/*	$OpenBSD: ldp.h,v 1.38 2017/03/04 00:06:10 renato Exp $ */
 
 /*
  * Copyright (c) 2013, 2016 Renato Westphal <renato@openbsd.org>
@@ -65,6 +65,7 @@
 #define MSG_TYPE_HELLO		0x0100
 #define MSG_TYPE_INIT		0x0200
 #define MSG_TYPE_KEEPALIVE	0x0201
+#define MSG_TYPE_CAPABILITY	0x0202 /* RFC 5561 */
 #define MSG_TYPE_ADDR		0x0300
 #define MSG_TYPE_ADDRWITHDRAW	0x0301
 #define MSG_TYPE_LABELMAPPING	0x0400
@@ -97,6 +98,9 @@
 #define TLV_TYPE_PW_STATUS	0x896A
 #define TLV_TYPE_PW_IF_PARAM	0x096B
 #define TLV_TYPE_PW_GROUP_ID	0x096C
+/* RFC 5561 */
+#define TLV_TYPE_RETURNED_TLVS	0x8304
+#define TLV_TYPE_DYNAMIC_CAP	0x8506
 /* RFC 7552 */
 #define TLV_TYPE_DUALSTACK	0x8701
 
@@ -198,6 +202,8 @@ struct hello_prms_opt16_tlv {
 #define S_UNASSIGN_TAI	0x00000029
 #define S_MISCONF_ERR	0x0000002A
 #define S_WITHDRAW_MTHD	0x0000002B
+/* RFC 5561 */
+#define	S_UNSSUPORTDCAP	0x0000002E
 /* RFC 7552 */
 #define	S_TRANS_MISMTCH	0x80000032
 #define	S_DS_NONCMPLNCE	0x80000033
@@ -229,6 +235,18 @@ struct status_tlv {
 #define STATUS_TLV_LEN		10
 #define	STATUS_FATAL		0x80000000
 
+struct capability_tlv {
+	uint16_t	type;
+	uint16_t	length;
+	uint8_t		reserved;
+};
+#define STATE_BIT		0x80
+
+#define F_CAP_TLV_RCVD_DYNAMIC	0x01
+
+#define CAP_TLV_DYNAMIC_SIZE	5
+#define CAP_TLV_DYNAMIC_LEN	1
+
 #define	AF_IPV4			0x1
 #define	AF_IPV6			0x2
 
diff --git a/usr.sbin/ldpd/ldpd.8 b/usr.sbin/ldpd/ldpd.8
index 9382991a2de..c270cba5fbe 100644
--- a/usr.sbin/ldpd/ldpd.8
+++ b/usr.sbin/ldpd/ldpd.8
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: ldpd.8,v 1.17 2017/03/03 23:30:57 renato Exp $
+.\"	$OpenBSD: ldpd.8,v 1.18 2017/03/04 00:06:10 renato Exp $
 .\"
 .\" Copyright (c) 2013, 2016 Renato Westphal <renato@openbsd.org>
 .\" Copyright (c) 2009 Michele Marchetto <michele@openbsd.org>
@@ -16,7 +16,7 @@
 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
-.Dd $Mdocdate: March 3 2017 $
+.Dd $Mdocdate: March 4 2017 $
 .Dt LDPD 8
 .Os
 .Sh NAME
@@ -132,6 +132,17 @@ socket used for communication with
 .Re
 .Pp
 .Rs
+.%A B. Thomas
+.%A K. Raza
+.%A S. Aggarwal
+.%A R. Aggarwal
+.%A JL. Le Roux
+.%D July 2009
+.%R RFC 5561
+.%T LDP Capabilities
+.Re
+.Pp
+.Rs
 .%A C. Pignataro
 .%A R. Asati
 .%D August 2012
diff --git a/usr.sbin/ldpd/ldpd.h b/usr.sbin/ldpd/ldpd.h
index f5b2a96cac1..88353d8ddaa 100644
--- a/usr.sbin/ldpd/ldpd.h
+++ b/usr.sbin/ldpd/ldpd.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ldpd.h,v 1.83 2017/03/03 23:36:06 renato Exp $ */
+/*	$OpenBSD: ldpd.h,v 1.84 2017/03/04 00:06:10 renato Exp $ */
 
 /*
  * Copyright (c) 2013, 2016 Renato Westphal <renato@openbsd.org>
@@ -228,10 +228,16 @@ struct notify_msg {
 	uint16_t	msg_type;	/* network byte order */
 	uint32_t	pw_status;
 	struct map	fec;
+	struct {
+		uint16_t	 type;
+		uint16_t	 length;
+		char		*data;
+	} rtlvs;
 	uint8_t		flags;
 };
 #define F_NOTIF_PW_STATUS	0x01	/* pseudowire status tlv present */
 #define F_NOTIF_FEC		0x02	/* fec tlv present */
+#define F_NOTIF_RETURNED_TLVS	0x04	/* returned tlvs present */
 
 struct if_addr {
 	LIST_ENTRY(if_addr)	 entry;
diff --git a/usr.sbin/ldpd/ldpe.h b/usr.sbin/ldpd/ldpe.h
index 25295375119..a298f6e3967 100644
--- a/usr.sbin/ldpd/ldpe.h
+++ b/usr.sbin/ldpd/ldpe.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ldpe.h,v 1.71 2017/03/03 23:44:35 renato Exp $ */
+/*	$OpenBSD: ldpe.h,v 1.72 2017/03/04 00:06:10 renato Exp $ */
 
 /*
  * Copyright (c) 2013, 2016 Renato Westphal <renato@openbsd.org>
@@ -104,6 +104,7 @@ struct nbr {
 	int			 flags;
 };
 #define F_NBR_GTSM_NEGOTIATED	 0x01
+#define F_NBR_CAP_DYNAMIC	 0x02
 
 RB_HEAD(nbr_id_head, nbr);
 RB_PROTOTYPE(nbr_id_head, nbr, id_tree, nbr_id_compare)
@@ -152,6 +153,8 @@ void	 recv_hello(struct in_addr, struct ldp_msg *, int, union ldpd_addr *,
 /* init.c */
 void	 send_init(struct nbr *);
 int	 recv_init(struct nbr *, char *, uint16_t);
+void	 send_capability(struct nbr *, uint16_t, int);
+int	 recv_capability(struct nbr *, char *, uint16_t);
 
 /* keepalive.c */
 void	 send_keepalive(struct nbr *);
@@ -160,6 +163,8 @@ int	 recv_keepalive(struct nbr *, char *, uint16_t);
 /* notification.c */
 void	 send_notification_full(struct tcp_conn *, struct notify_msg *);
 void	 send_notification(struct tcp_conn *, uint32_t, uint32_t, uint16_t);
+void	 send_notification_rtlvs(struct nbr *, uint32_t, uint32_t, uint16_t,
+	    uint16_t, uint16_t, char *);
 int	 recv_notification(struct nbr *, char *, uint16_t);
 int	 gen_status_tlv(struct ibuf *, uint32_t, uint32_t, uint16_t);
 
diff --git a/usr.sbin/ldpd/logmsg.c b/usr.sbin/ldpd/logmsg.c
index 568533f2dee..e71b6f79c81 100644
--- a/usr.sbin/ldpd/logmsg.c
+++ b/usr.sbin/ldpd/logmsg.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: logmsg.c,v 1.2 2017/03/04 00:03:04 renato Exp $ */
+/*	$OpenBSD: logmsg.c,v 1.3 2017/03/04 00:06:10 renato Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -303,6 +303,8 @@ msg_name(uint16_t msg)
 		return ("initialization");
 	case MSG_TYPE_KEEPALIVE:
 		return ("keepalive");
+	case MSG_TYPE_CAPABILITY:
+		return ("capability");
 	case MSG_TYPE_ADDR:
 		return ("address");
 	case MSG_TYPE_ADDRWITHDRAW:
@@ -396,6 +398,8 @@ status_code_name(uint32_t status)
 		return ("Generic Misconfiguration Error");
 	case S_WITHDRAW_MTHD:
 		return ("Label Withdraw PW Status Method");
+	case S_UNSSUPORTDCAP:
+		return ("Unsupported Capability");
 	case S_TRANS_MISMTCH:
 		return ("Transport Connection Mismatch");
 	case S_DS_NONCMPLNCE:
diff --git a/usr.sbin/ldpd/notification.c b/usr.sbin/ldpd/notification.c
index b8fab3476b5..962a1fea78c 100644
--- a/usr.sbin/ldpd/notification.c
+++ b/usr.sbin/ldpd/notification.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: notification.c,v 1.44 2017/03/03 23:50:45 renato Exp $ */
+/*	$OpenBSD: notification.c,v 1.45 2017/03/04 00:06:10 renato Exp $ */
 
 /*
  * Copyright (c) 2009 Michele Marchetto <michele@openbsd.org>
@@ -25,6 +25,7 @@
 #include "log.h"
 #include "ldpe.h"
 
+static int	 gen_returned_tlvs(struct ibuf *, uint16_t, uint16_t, char *);
 static void	 log_msg_notification(int, struct nbr *, struct notify_msg *);
 
 void
@@ -48,6 +49,8 @@ send_notification_full(struct tcp_conn *tcp, struct notify_msg *nm)
 			break;
 		}
 	}
+	if (nm->flags & F_NOTIF_RETURNED_TLVS)
+		size += TLV_HDR_SIZE * 2 + nm->rtlvs.length;
 
 	if ((buf = ibuf_open(size)) == NULL)
 		fatal(__func__);
@@ -61,6 +64,9 @@ send_notification_full(struct tcp_conn *tcp, struct notify_msg *nm)
 		err |= gen_pw_status_tlv(buf, nm->pw_status);
 	if (nm->flags & F_NOTIF_FEC)
 		err |= gen_fec_tlv(buf, &nm->fec);
+	if (nm->flags & F_NOTIF_RETURNED_TLVS)
+		err |= gen_returned_tlvs(buf, nm->rtlvs.type, nm->rtlvs.length,
+		    nm->rtlvs.data);
 	if (err) {
 		ibuf_free(buf);
 		return;
@@ -89,6 +95,27 @@ send_notification(struct tcp_conn *tcp, uint32_t status_code, uint32_t msg_id,
 	send_notification_full(tcp, &nm);
 }
 
+void
+send_notification_rtlvs(struct nbr *nbr, uint32_t status_code, uint32_t msg_id,
+    uint16_t msg_type, uint16_t tlv_type, uint16_t tlv_len, char *tlv_data)
+{
+	struct notify_msg	 nm;
+
+	memset(&nm, 0, sizeof(nm));
+	nm.status_code = status_code;
+	nm.msg_id = msg_id;
+	nm.msg_type = msg_type;
+	/* do not append the given TLV if it's too big (shouldn't happen) */
+	if (tlv_len < 1024) {
+		nm.rtlvs.type = tlv_type;
+		nm.rtlvs.length = tlv_len;
+		nm.rtlvs.data = tlv_data;
+		nm.flags |= F_NOTIF_RETURNED_TLVS;
+	}
+
+	send_notification_full(nbr->tcp, &nm);
+}
+
 int
 recv_notification(struct nbr *nbr, char *buf, uint16_t len)
 {
@@ -121,6 +148,7 @@ recv_notification(struct nbr *nbr, char *buf, uint16_t len)
 	/* Optional Parameters */
 	while (len > 0) {
 		struct tlv 	tlv;
+		uint16_t	tlv_type;
 		uint16_t	tlv_len;
 
 		if (len < sizeof(tlv)) {
@@ -129,6 +157,7 @@ recv_notification(struct nbr *nbr, char *buf, uint16_t len)
 		}
 
 		memcpy(&tlv, buf, TLV_HDR_SIZE);
+		tlv_type = ntohs(tlv.type);
 		tlv_len = ntohs(tlv.length);
 		if (tlv_len + TLV_HDR_SIZE > len) {
 			session_shutdown(nbr, S_BAD_TLV_LEN, msg.id, msg.type);
@@ -137,7 +166,7 @@ recv_notification(struct nbr *nbr, char *buf, uint16_t len)
 		buf += TLV_HDR_SIZE;
 		len -= TLV_HDR_SIZE;
 
-		switch (ntohs(tlv.type)) {
+		switch (tlv_type) {
 		case TLV_TYPE_EXTSTATUS:
 		case TLV_TYPE_RETURNEDPDU:
 		case TLV_TYPE_RETURNEDMSG:
@@ -167,8 +196,8 @@ recv_notification(struct nbr *nbr, char *buf, uint16_t len)
 			break;
 		default:
 			if (!(ntohs(tlv.type) & UNKNOWN_FLAG))
-				send_notification(nbr->tcp, S_UNKNOWN_TLV,
-				    msg.id, msg.type);
+				send_notification_rtlvs(nbr, S_UNKNOWN_TLV,
+				    msg.id, msg.type, tlv_type, tlv_len, buf);
 			/* ignore unknown tlv */
 			break;
 		}
@@ -230,6 +259,26 @@ gen_status_tlv(struct ibuf *buf, uint32_t status_code, uint32_t msg_id,
 	return (ibuf_add(buf, &st, STATUS_SIZE));
 }
 
+static int
+gen_returned_tlvs(struct ibuf *buf, uint16_t type, uint16_t length,
+    char *tlv_data)
+{
+	struct tlv	 rtlvs;
+	struct tlv	 tlv;
+	int		 err;
+
+	rtlvs.type = htons(TLV_TYPE_RETURNED_TLVS);
+	rtlvs.length = htons(length + TLV_HDR_SIZE);
+	tlv.type = htons(type);
+	tlv.length = htons(length);
+
+	err = ibuf_add(buf, &rtlvs, sizeof(rtlvs));
+	err |= ibuf_add(buf, &tlv, sizeof(tlv));
+	err |= ibuf_add(buf, tlv_data, length);
+
+	return (err);
+}
+
 void
 log_msg_notification(int out, struct nbr *nbr, struct notify_msg *nm)
 {
diff --git a/usr.sbin/ldpd/packet.c b/usr.sbin/ldpd/packet.c
index cfb9d2265d1..1e03a09bcee 100644
--- a/usr.sbin/ldpd/packet.c
+++ b/usr.sbin/ldpd/packet.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: packet.c,v 1.69 2017/03/03 23:44:35 renato Exp $ */
+/*	$OpenBSD: packet.c,v 1.70 2017/03/04 00:06:10 renato Exp $ */
 
 /*
  * Copyright (c) 2013, 2016 Renato Westphal <renato@openbsd.org>
@@ -518,13 +518,7 @@ session_read(int fd, short event, void *arg)
 					return;
 				}
 				break;
-			case MSG_TYPE_ADDR:
-			case MSG_TYPE_ADDRWITHDRAW:
-			case MSG_TYPE_LABELMAPPING:
-			case MSG_TYPE_LABELREQUEST:
-			case MSG_TYPE_LABELWITHDRAW:
-			case MSG_TYPE_LABELRELEASE:
-			case MSG_TYPE_LABELABORTREQ:
+			default:
 				if (nbr->state != NBR_STA_OPER) {
 					session_shutdown(nbr, S_SHUTDOWN,
 					    msg->id, msg->type);
@@ -532,8 +526,6 @@ session_read(int fd, short event, void *arg)
 					return;
 				}
 				break;
-			default:
-				break;
 			}
 
 			/* switch LDP packet type */
@@ -547,6 +539,9 @@ session_read(int fd, short event, void *arg)
 			case MSG_TYPE_KEEPALIVE:
 				ret = recv_keepalive(nbr, pdu, msg_size);
 				break;
+			case MSG_TYPE_CAPABILITY:
+				ret = recv_capability(nbr, pdu, msg_size);
+				break;
 			case MSG_TYPE_ADDR:
 			case MSG_TYPE_ADDRWITHDRAW:
 				ret = recv_address(nbr, pdu, msg_size);