bfdd,lib: implement protocol profile selection

Implement the infrastructure for other protocols daemon (e.g. `bgpd`,
`ospfd`, `isisd` etc...) to communicate to BFD daemon which profile
they want to use with their peers.

It was also added the ability for protocols to change profile while
running (no need to remove the registration and then register again).

The protocols message building function was rewritten to support
multiple arguments through `struct bfd_session_arg`, so we can
implement new features without the need of changing function
prototypes. The old function was also rewritten to keep
compatibility.

The profile message part is only available for BFD daemon at the
moment.

Signed-off-by: Rafael Zalamena <rzalamena@opensourcerouting.org>

3 files changed, 41 insertions, 6 deletions

diff --git a/bfdd/bfd.c b/bfdd/bfd.c
index a021b5cab..f51136e98 100644
--- a/bfdd/bfd.c
+++ b/bfdd/bfd.c
@@ -765,6 +765,15 @@ static void _bfd_session_update(struct bfd_session *bs,
 	 */
 	bs->peer_profile.admin_shutdown = bpc->bpc_shutdown;
 	bfd_set_shutdown(bs, bpc->bpc_shutdown);
+
+	/*
+	 * Apply profile last: it also calls `bfd_set_shutdown`.
+	 *
+	 * There is no problem calling `shutdown` twice if the value doesn't
+	 * change or if it is overriden by peer specific configuration.
+	 */
+	if (bpc->bpc_has_profile)
+		bfd_profile_apply(bpc->bpc_profile, bs);
 }
 
 static int bfd_session_update(struct bfd_session *bs, struct bfd_peer_cfg *bpc)
diff --git a/bfdd/bfdctl.h b/bfdd/bfdctl.h
index 4ce23a8f2..95cfcb110 100644
--- a/bfdd/bfdctl.h
+++ b/bfdd/bfdctl.h
@@ -90,6 +90,9 @@ struct bfd_peer_cfg {
 
 	bool bpc_cbit;
 
+	bool bpc_has_profile;
+	char bpc_profile[64];
+
 	/* Status information */
 	enum bfd_peer_status bpc_bps;
 	uint32_t bpc_id;
diff --git a/bfdd/ptm_adapter.c b/bfdd/ptm_adapter.c
index 25938dd9f..0abbdf3dc 100644
--- a/bfdd/ptm_adapter.c
+++ b/bfdd/ptm_adapter.c
@@ -85,6 +85,7 @@ static void debug_printbpc(const struct bfd_peer_cfg *bpc, const char *fmt, ...)
 {
 	char timers[3][128] = {};
 	char addr[3][128] = {};
+	char profile[128] = {};
 	char cbit_str[32];
 	char msgbuf[256];
 	va_list vl;
@@ -119,13 +120,17 @@ static void debug_printbpc(const struct bfd_peer_cfg *bpc, const char *fmt, ...)
 
 	snprintf(cbit_str, sizeof(cbit_str), " cbit:0x%02x", bpc->bpc_cbit);
 
+	if (bpc->bpc_has_profile)
+		snprintf(profile, sizeof(profile), " profile:%s",
+			 bpc->bpc_profile);
+
 	va_start(vl, fmt);
 	vsnprintf(msgbuf, sizeof(msgbuf), fmt, vl);
 	va_end(vl);
 
-	zlog_debug("%s [mhop:%s %s%s%s%s%s%s%s]", msgbuf,
+	zlog_debug("%s [mhop:%s %s%s%s%s%s%s%s%s]", msgbuf,
 		   bpc->bpc_mhop ? "yes" : "no", addr[0], addr[1], addr[2],
-		   timers[0], timers[1], timers[2], cbit_str);
+		   timers[0], timers[1], timers[2], cbit_str, profile);
 }
 
 static int _ptm_msg_address(struct stream *msg, int family, const void *addr)
@@ -301,6 +306,8 @@ static int _ptm_msg_read(struct stream *msg, int command, vrf_id_t vrf_id,
 	 *     - c: ifname length
 	 *     - X bytes: interface name
 	 * - c: bfd_cbit
+	 * - c: profile name length.
+	 * - X bytes: profile name.
 	 *
 	 * q(64), l(32), w(16), c(8)
 	 */
@@ -381,6 +388,14 @@ static int _ptm_msg_read(struct stream *msg, int command, vrf_id_t vrf_id,
 
 	STREAM_GETC(msg, bpc->bpc_cbit);
 
+	/* Handle profile names. */
+	STREAM_GETC(msg, ifnamelen);
+	bpc->bpc_has_profile = ifnamelen > 0;
+	if (bpc->bpc_has_profile) {
+		STREAM_GET(bpc->bpc_profile, msg, ifnamelen);
+		bpc->bpc_profile[ifnamelen] = 0;
+	}
+
 	/* Sanity check: peer and local address must match IP types. */
 	if (bpc->bpc_local.sa_sin.sin_family != 0
 	    && (bpc->bpc_local.sa_sin.sin_family
@@ -421,10 +436,18 @@ static void bfdd_dest_register(struct stream *msg, vrf_id_t vrf_id)
 		/* Protocol created peers are 'no shutdown' by default. */
 		bs->peer_profile.admin_shutdown = false;
 	} else {
-		/* Don't try to change echo/shutdown state. */
-		bpc.bpc_echo = CHECK_FLAG(bs->flags, BFD_SESS_FLAG_ECHO);
-		bpc.bpc_shutdown =
-			CHECK_FLAG(bs->flags, BFD_SESS_FLAG_SHUTDOWN);
+		/*
+		 * BFD session was already created, we are just updating the
+		 * current peer.
+		 *
+		 * `ptm-bfd` (or `HAVE_BFDD == 0`) is the only implementation
+		 * that allow users to set peer specific timers via protocol.
+		 * BFD daemon (this code) on the other hand only supports
+		 * changing peer configuration manually (through `peer` node)
+		 * or via profiles.
+		 */
+		if (bpc.bpc_has_profile)
+			bfd_profile_apply(bpc.bpc_profile, bs);
 	}
 
 	/* Create client peer notification register. */