ldpd: 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).

Signed-off-by: Renato Westphal <renato@opensourcerouting.org>

1 files changed, 147 insertions, 5 deletions

diff --git a/ldpd/init.c b/ldpd/init.c
index 030bff2f51..4b3eab270d 100644
--- a/ldpd/init.c
+++ b/ldpd/init.c
@@ -24,6 +24,7 @@
 #include "ldp_debug.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)
@@ -34,15 +35,16 @@ send_init(struct nbr *nbr)
 
 	debug_msg_send("initialization: lsr-id %s", 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;
@@ -57,6 +59,7 @@ 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;
 
 	debug_msg_recv("initialization: lsr-id %s", inet_ntoa(nbr->id));
 
@@ -93,6 +96,7 @@ 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)) {
@@ -101,6 +105,7 @@ 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);
@@ -109,17 +114,42 @@ 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;
 		}
@@ -145,6 +175,104 @@ 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)
 {
@@ -163,3 +291,17 @@ 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));
+}