bfdd: Add BFD "log-session-changes" feature.

Add the BFD "log-session-changes" via the YANG and northbound API. Also
add the configured value to show and operational state.

Signed-off-by: Acee Lindem <acee@lindem.com>

8 files changed, 183 insertions, 13 deletions

diff --git a/bfdd/bfd.c b/bfdd/bfd.c
index fade89d04f..8d5306aaaf 100644
--- a/bfdd/bfd.c
+++ b/bfdd/bfd.c
@@ -79,6 +79,7 @@ static void bfd_profile_set_default(struct bfd_profile *bp)
 	bp->detection_multiplier = BFD_DEFDETECTMULT;
 	bp->echo_mode = false;
 	bp->passive = false;
+	bp->log_session_changes = false;
 	bp->minimum_ttl = BFD_DEF_MHOP_TTL;
 	bp->min_echo_rx = BFD_DEF_REQ_MIN_ECHO_RX;
 	bp->min_echo_tx = BFD_DEF_DES_MIN_ECHO_TX;
@@ -210,6 +211,12 @@ void bfd_session_apply(struct bfd_session *bs)
 	else
 		bfd_set_shutdown(bs, bs->peer_profile.admin_shutdown);
 
+	/* Toggle 'no log-session-changes' if default value. */
+	if (bs->peer_profile.log_session_changes == false)
+		bfd_set_log_session_changes(bs, bp->log_session_changes);
+	else
+		bfd_set_log_session_changes(bs, bs->peer_profile.log_session_changes);
+
 	/* If session interval changed negotiate new timers. */
 	if (bs->ses_state == PTM_BFD_UP
 	    && (bs->timers.desired_min_tx != min_tx
@@ -574,6 +581,9 @@ void ptm_bfd_sess_up(struct bfd_session *bfd)
 			zlog_debug("state-change: [%s] %s -> %s",
 				   bs_to_string(bfd), state_list[old_state].str,
 				   state_list[bfd->ses_state].str);
+		if (CHECK_FLAG(bfd->flags, BFD_SESS_FLAG_LOG_SESSION_CHANGES))
+			zlog_notice("Session-Change: [%s] %s -> %s", bs_to_string(bfd),
+				    state_list[old_state].str, state_list[bfd->ses_state].str);
 	}
 }
 
@@ -621,6 +631,11 @@ void ptm_bfd_sess_dn(struct bfd_session *bfd, uint8_t diag)
 				   bs_to_string(bfd), state_list[old_state].str,
 				   state_list[bfd->ses_state].str,
 				   get_diag_str(bfd->local_diag));
+		if (CHECK_FLAG(bfd->flags, BFD_SESS_FLAG_LOG_SESSION_CHANGES) &&
+		    old_state == PTM_BFD_UP)
+			zlog_notice("Session-Change: [%s] %s -> %s reason:%s", bs_to_string(bfd),
+				    state_list[old_state].str, state_list[bfd->ses_state].str,
+				    get_diag_str(bfd->local_diag));
 	}
 
 	/* clear peer's mac address */
@@ -651,6 +666,9 @@ void ptm_sbfd_sess_up(struct bfd_session *bfd)
 		if (bglobal.debug_peer_event)
 			zlog_info("state-change: [%s] %s -> %s", bs_to_string(bfd),
 				  state_list[old_state].str, state_list[bfd->ses_state].str);
+		if (CHECK_FLAG(bfd->flags, BFD_SESS_FLAG_LOG_SESSION_CHANGES))
+			zlog_notice("Session-Change: [%s] %s -> %s", bs_to_string(bfd),
+				    state_list[old_state].str, state_list[bfd->ses_state].str);
 	}
 }
 
@@ -693,6 +711,11 @@ void ptm_sbfd_init_sess_dn(struct bfd_session *bfd, uint8_t diag)
 			zlog_debug("state-change: [%s] %s -> %s reason:%s", bs_to_string(bfd),
 				   state_list[old_state].str, state_list[bfd->ses_state].str,
 				   get_diag_str(bfd->local_diag));
+		if (CHECK_FLAG(bfd->flags, BFD_SESS_FLAG_LOG_SESSION_CHANGES) &&
+		    old_state == PTM_BFD_UP)
+			zlog_notice("Session-Change: [%s] %s -> %s reason:%s", bs_to_string(bfd),
+				    state_list[old_state].str, state_list[bfd->ses_state].str,
+				    get_diag_str(bfd->local_diag));
 	}
 	/* reset local address ,it might has been be changed after bfd is up*/
 	//memset(&bfd->local_address, 0, sizeof(bfd->local_address));
@@ -721,6 +744,11 @@ void ptm_sbfd_echo_sess_dn(struct bfd_session *bfd, uint8_t diag)
 			zlog_warn("state-change: [%s] %s -> %s reason:%s", bs_to_string(bfd),
 				  state_list[old_state].str, state_list[bfd->ses_state].str,
 				  get_diag_str(bfd->local_diag));
+		if (CHECK_FLAG(bfd->flags, BFD_SESS_FLAG_LOG_SESSION_CHANGES) &&
+		    old_state == PTM_BFD_UP)
+			zlog_notice("Session-Change: [%s] %s -> %s reason:%s", bs_to_string(bfd),
+				    state_list[old_state].str, state_list[bfd->ses_state].str,
+				    get_diag_str(bfd->local_diag));
 	}
 }
 
@@ -944,6 +972,11 @@ static void _bfd_session_update(struct bfd_session *bs,
 	bs->peer_profile.echo_mode = bpc->bpc_echo;
 	bfd_set_echo(bs, bpc->bpc_echo);
 
+	if (bpc->bpc_log_session_changes)
+		SET_FLAG(bs->flags, BFD_SESS_FLAG_LOG_SESSION_CHANGES);
+	else
+		UNSET_FLAG(bs->flags, BFD_SESS_FLAG_LOG_SESSION_CHANGES);
+
 	/*
 	 * Shutdown needs to be the last in order to avoid timers enable when
 	 * the session is disabled.
@@ -1608,6 +1641,14 @@ void bfd_set_passive_mode(struct bfd_session *bs, bool passive)
 	}
 }
 
+void bfd_set_log_session_changes(struct bfd_session *bs, bool log_session_changes)
+{
+	if (log_session_changes)
+		SET_FLAG(bs->flags, BFD_SESS_FLAG_LOG_SESSION_CHANGES);
+	else
+		UNSET_FLAG(bs->flags, BFD_SESS_FLAG_LOG_SESSION_CHANGES);
+}
+
 /*
  * Helper functions.
  */
diff --git a/bfdd/bfd.h b/bfdd/bfd.h
index 645a76596f..75efb483fe 100644
--- a/bfdd/bfd.h
+++ b/bfdd/bfd.h
@@ -84,6 +84,7 @@ struct bfd_peer_cfg {
 
 	bool bpc_cbit;
 	bool bpc_passive;
+	bool bpc_log_session_changes;
 
 	bool bpc_has_profile;
 	char bpc_profile[64];
@@ -224,21 +225,22 @@ enum bfd_diagnosticis {
 /* BFD session flags */
 enum bfd_session_flags {
 	BFD_SESS_FLAG_NONE = 0,
-	BFD_SESS_FLAG_ECHO = 1 << 0,	/* BFD Echo functionality */
-	BFD_SESS_FLAG_ECHO_ACTIVE = 1 << 1, /* BFD Echo Packets are being sent
+	BFD_SESS_FLAG_ECHO = 1 << 0,		     /* BFD Echo functionality */
+	BFD_SESS_FLAG_ECHO_ACTIVE = 1 << 1,	     /* BFD Echo Packets are being sent
 					     * actively
 					     */
-	BFD_SESS_FLAG_MH = 1 << 2,	  /* BFD Multi-hop session */
-	BFD_SESS_FLAG_IPV6 = 1 << 4,	/* BFD IPv6 session */
-	BFD_SESS_FLAG_SEND_EVT_ACTIVE = 1 << 5, /* send event timer active */
-	BFD_SESS_FLAG_SEND_EVT_IGNORE = 1 << 6, /* ignore send event when timer
+	BFD_SESS_FLAG_MH = 1 << 2,		     /* BFD Multi-hop session */
+	BFD_SESS_FLAG_IPV6 = 1 << 4,		     /* BFD IPv6 session */
+	BFD_SESS_FLAG_SEND_EVT_ACTIVE = 1 << 5,	     /* send event timer active */
+	BFD_SESS_FLAG_SEND_EVT_IGNORE = 1 << 6,	     /* ignore send event when timer
 						 * expires
 						 */
-	BFD_SESS_FLAG_SHUTDOWN = 1 << 7,	/* disable BGP peer function */
-	BFD_SESS_FLAG_CONFIG = 1 << 8, /* Session configured with bfd NB API */
-	BFD_SESS_FLAG_CBIT = 1 << 9,   /* CBIT is set */
-	BFD_SESS_FLAG_PASSIVE = 1 << 10, /* Passive mode */
-	BFD_SESS_FLAG_MAC_SET = 1 << 11, /* MAC of peer known */
+	BFD_SESS_FLAG_SHUTDOWN = 1 << 7,	     /* disable BGP peer function */
+	BFD_SESS_FLAG_CONFIG = 1 << 8,		     /* Session configured with bfd NB API */
+	BFD_SESS_FLAG_CBIT = 1 << 9,		     /* CBIT is set */
+	BFD_SESS_FLAG_PASSIVE = 1 << 10,	     /* Passive mode */
+	BFD_SESS_FLAG_MAC_SET = 1 << 11,	     /* MAC of peer known */
+	BFD_SESS_FLAG_LOG_SESSION_CHANGES = 1 << 12, /* Log session changes */
 };
 
 enum bfd_mode_type {
@@ -297,6 +299,8 @@ struct bfd_profile {
 	bool admin_shutdown;
 	/** Passive mode. */
 	bool passive;
+	/** Log session changes. */
+	bool log_session_changes;
 	/** Minimum expected TTL value. */
 	uint8_t minimum_ttl;
 
@@ -683,6 +687,14 @@ void bfd_set_shutdown(struct bfd_session *bs, bool shutdown);
 void bfd_set_passive_mode(struct bfd_session *bs, bool passive);
 
 /**
+ * Set the BFD session to log or not log session changes.
+ *
+ * \param bs the BFD session.
+ * \param log_session indicates whether or not to log session changes.
+ */
+void bfd_set_log_session_changes(struct bfd_session *bs, bool log_session);
+
+/**
  * Picks the BFD session configuration from the appropriated source:
  * if using the default peer configuration prefer profile (if it exists),
  * otherwise use session.
diff --git a/bfdd/bfdd_cli.c b/bfdd/bfdd_cli.c
index a1710ec127..016e63b192 100644
--- a/bfdd/bfdd_cli.c
+++ b/bfdd/bfdd_cli.c
@@ -754,6 +754,21 @@ void bfd_cli_show_passive(struct vty *vty, const struct lyd_node *dnode,
 		yang_dnode_get_bool(dnode, NULL) ? "" : "no ");
 }
 
+DEFPY_YANG(bfd_peer_log_session_changes, bfd_peer_log_session_changes_cmd,
+	   "[no] log-session-changes",
+	   NO_STR
+	   "Log Up/Down changes for the session\n")
+{
+	nb_cli_enqueue_change(vty, "./log-session-changes", NB_OP_MODIFY, no ? "false" : "true");
+	return nb_cli_apply_changes(vty, NULL);
+}
+
+void bfd_cli_show_log_session_changes(struct vty *vty, const struct lyd_node *dnode,
+				      bool show_defaults)
+{
+	vty_out(vty, "  %slog-session-changes\n", yang_dnode_get_bool(dnode, NULL) ? "" : "no ");
+}
+
 DEFPY_YANG(
 	bfd_peer_minimum_ttl, bfd_peer_minimum_ttl_cmd,
 	"[no] minimum-ttl (1-254)$ttl",
@@ -1063,6 +1078,9 @@ ALIAS_YANG(bfd_peer_passive, bfd_profile_passive_cmd,
       NO_STR
       "Don't attempt to start sessions\n")
 
+ALIAS_YANG(bfd_peer_log_session_changes, bfd_profile_log_session_changes_cmd,
+	   "[no] log-session-changes", NO_STR "Log Up/Down session changes in the profile\n")
+
 ALIAS_YANG(bfd_peer_minimum_ttl, bfd_profile_minimum_ttl_cmd,
       "[no] minimum-ttl (1-254)$ttl",
       NO_STR
@@ -1329,6 +1347,7 @@ bfdd_cli_init(void)
 	install_element(BFD_PEER_NODE, &bfd_peer_echo_receive_interval_cmd);
 	install_element(BFD_PEER_NODE, &bfd_peer_profile_cmd);
 	install_element(BFD_PEER_NODE, &bfd_peer_passive_cmd);
+	install_element(BFD_PEER_NODE, &bfd_peer_log_session_changes_cmd);
 	install_element(BFD_PEER_NODE, &bfd_peer_minimum_ttl_cmd);
 	install_element(BFD_PEER_NODE, &no_bfd_peer_minimum_ttl_cmd);
 
@@ -1350,6 +1369,7 @@ bfdd_cli_init(void)
 	install_element(BFD_PROFILE_NODE, &bfd_profile_echo_transmit_interval_cmd);
 	install_element(BFD_PROFILE_NODE, &bfd_profile_echo_receive_interval_cmd);
 	install_element(BFD_PROFILE_NODE, &bfd_profile_passive_cmd);
+	install_element(BFD_PROFILE_NODE, &bfd_profile_log_session_changes_cmd);
 	install_element(BFD_PROFILE_NODE, &bfd_profile_minimum_ttl_cmd);
 	install_element(BFD_PROFILE_NODE, &no_bfd_profile_minimum_ttl_cmd);
 }
diff --git a/bfdd/bfdd_nb.c b/bfdd/bfdd_nb.c
index f60d8397bb..7595d8d05e 100644
--- a/bfdd/bfdd_nb.c
+++ b/bfdd/bfdd_nb.c
@@ -70,6 +70,13 @@ const struct frr_yang_module_info frr_bfdd_info = {
 				.cli_show = bfd_cli_show_passive,
                         }
                 },
+                {
+                        .xpath = "/frr-bfdd:bfdd/bfd/profile/log-session-changes",
+                        .cbs = {
+                                .modify = bfdd_bfd_profile_log_session_changes_modify,
+				.cli_show = bfd_cli_show_log_session_changes,
+                        }
+                },
 		{
 			.xpath = "/frr-bfdd:bfdd/bfd/profile/minimum-ttl",
 			.cbs = {
@@ -161,6 +168,13 @@ const struct frr_yang_module_info frr_bfdd_info = {
 			}
 		},
 		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/log-session-changes",
+			.cbs = {
+				.modify = bfdd_bfd_sessions_single_hop_log_session_changes_modify,
+				.cli_show = bfd_cli_show_log_session_changes,
+			}
+		},
+		{
 			.xpath = "/frr-bfdd:bfdd/bfd/sessions/single-hop/echo-mode",
 			.cbs = {
 				.modify = bfdd_bfd_sessions_single_hop_echo_mode_modify,
@@ -357,6 +371,13 @@ const struct frr_yang_module_info frr_bfdd_info = {
 			}
 		},
 		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/log-session-changes",
+			.cbs = {
+				.modify = bfdd_bfd_sessions_single_hop_log_session_changes_modify,
+				.cli_show = bfd_cli_show_log_session_changes,
+			}
+		},
+		{
 			.xpath = "/frr-bfdd:bfdd/bfd/sessions/multi-hop/minimum-ttl",
 			.cbs = {
 				.modify = bfdd_bfd_sessions_multi_hop_minimum_ttl_modify,
@@ -573,6 +594,13 @@ const struct frr_yang_module_info frr_bfdd_info = {
 			}
 		},
 		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/sbfd-echo/log-session-changes",
+			.cbs = {
+				.modify = bfdd_bfd_sessions_single_hop_log_session_changes_modify,
+				.cli_show = bfd_cli_show_log_session_changes,
+			}
+		},
+		{
 			.xpath = "/frr-bfdd:bfdd/bfd/sessions/sbfd-echo/bfd-mode",
 			.cbs = {
 				.modify = bfdd_bfd_sessions_bfd_mode_modify,
@@ -789,6 +817,13 @@ const struct frr_yang_module_info frr_bfdd_info = {
 			}
 		},
 		{
+			.xpath = "/frr-bfdd:bfdd/bfd/sessions/sbfd-init/log-session-changes",
+			.cbs = {
+				.modify = bfdd_bfd_sessions_single_hop_log_session_changes_modify,
+				.cli_show = bfd_cli_show_log_session_changes,
+			}
+		},
+		{
 			.xpath = "/frr-bfdd:bfdd/bfd/sessions/sbfd-init/bfd-mode",
 			.cbs = {
 				.modify = bfdd_bfd_sessions_bfd_mode_modify,
diff --git a/bfdd/bfdd_nb.h b/bfdd/bfdd_nb.h
index 6621973ae3..ce6ee0d002 100644
--- a/bfdd/bfdd_nb.h
+++ b/bfdd/bfdd_nb.h
@@ -24,6 +24,7 @@ int bfdd_bfd_profile_required_receive_interval_modify(
 	struct nb_cb_modify_args *args);
 int bfdd_bfd_profile_administrative_down_modify(struct nb_cb_modify_args *args);
 int bfdd_bfd_profile_passive_mode_modify(struct nb_cb_modify_args *args);
+int bfdd_bfd_profile_log_session_changes_modify(struct nb_cb_modify_args *args);
 int bfdd_bfd_profile_minimum_ttl_modify(struct nb_cb_modify_args *args);
 int bfdd_bfd_profile_echo_mode_modify(struct nb_cb_modify_args *args);
 int bfdd_bfd_profile_desired_echo_transmission_interval_modify(
@@ -54,6 +55,7 @@ int bfdd_bfd_sessions_single_hop_administrative_down_modify(
 	struct nb_cb_modify_args *args);
 int bfdd_bfd_sessions_single_hop_passive_mode_modify(
 	struct nb_cb_modify_args *args);
+int bfdd_bfd_sessions_single_hop_log_session_changes_modify(struct nb_cb_modify_args *args);
 int bfdd_bfd_sessions_single_hop_echo_mode_modify(
 	struct nb_cb_modify_args *args);
 int bfdd_bfd_sessions_single_hop_desired_echo_transmission_interval_modify(
@@ -229,6 +231,8 @@ void bfd_cli_peer_profile_show(struct vty *vty, const struct lyd_node *dnode,
 			       bool show_defaults);
 void bfd_cli_show_passive(struct vty *vty, const struct lyd_node *dnode,
 			  bool show_defaults);
+void bfd_cli_show_log_session_changes(struct vty *vty, const struct lyd_node *dnode,
+				      bool show_defaults);
 void bfd_cli_show_minimum_ttl(struct vty *vty, const struct lyd_node *dnode,
 			      bool show_defaults);
 
diff --git a/bfdd/bfdd_nb_config.c b/bfdd/bfdd_nb_config.c
index f553d56652..e2d7f5061d 100644
--- a/bfdd/bfdd_nb_config.c
+++ b/bfdd/bfdd_nb_config.c
@@ -596,6 +596,23 @@ int bfdd_bfd_profile_passive_mode_modify(struct nb_cb_modify_args *args)
 }
 
 /*
+ * XPath: /frr-bfdd:bfdd/bfd/profile/log-session-changes
+ */
+int bfdd_bfd_profile_log_session_changes_modify(struct nb_cb_modify_args *args)
+{
+	struct bfd_profile *bp;
+
+	if (args->event != NB_EV_APPLY)
+		return NB_OK;
+
+	bp = nb_running_get_entry(args->dnode, NULL, true);
+	bp->log_session_changes = yang_dnode_get_bool(args->dnode, NULL);
+	bfd_profile_update(bp);
+
+	return NB_OK;
+}
+
+/*
  * XPath: /frr-bfdd:bfdd/bfd/profile/minimum-ttl
  */
 int bfdd_bfd_profile_minimum_ttl_modify(struct nb_cb_modify_args *args)
@@ -904,6 +921,38 @@ int bfdd_bfd_sessions_single_hop_passive_mode_modify(
 }
 
 /*
+ * XPath: /frr-bfdd:bfdd/bfd/sessions/single-hop/log-session-changes
+ *        /frr-bfdd:bfdd/bfd/sessions/multi-hop/log-session-changes
+ *        /frr-bfdd:bfdd/bfd/sessions/sbfd_echo/log-session-changes
+ *        /frr-bfdd:bfdd/bfd/sessions/sbfd_init/log-session-changes
+ */
+int bfdd_bfd_sessions_single_hop_log_session_changes_modify(struct nb_cb_modify_args *args)
+{
+	struct bfd_session *bs;
+	bool log_session_changes;
+
+	switch (args->event) {
+	case NB_EV_VALIDATE:
+	case NB_EV_PREPARE:
+		return NB_OK;
+
+	case NB_EV_APPLY:
+		break;
+
+	case NB_EV_ABORT:
+		return NB_OK;
+	}
+
+	log_session_changes = yang_dnode_get_bool(args->dnode, NULL);
+
+	bs = nb_running_get_entry(args->dnode, NULL, true);
+	bs->peer_profile.log_session_changes = log_session_changes;
+	bfd_session_apply(bs);
+
+	return NB_OK;
+}
+
+/*
  * XPath: /frr-bfdd:bfdd/bfd/sessions/sbfd-init/bfd-mode
  *        /frr-bfdd:bfdd/bfd/sessions/sbfd-echo/bfd-mode
  */
diff --git a/bfdd/bfdd_vty.c b/bfdd/bfdd_vty.c
index c281197849..32e3bc27c0 100644
--- a/bfdd/bfdd_vty.c
+++ b/bfdd/bfdd_vty.c
@@ -164,9 +164,10 @@ static void _display_peer(struct vty *vty, struct bfd_session *bs)
 		vty_out(vty, "\t\tPassive mode\n");
 	else
 		vty_out(vty, "\t\tActive mode\n");
+	if (CHECK_FLAG(bs->flags, BFD_SESS_FLAG_LOG_SESSION_CHANGES))
+		vty_out(vty, "\t\tLog session changes\n");
 	if (CHECK_FLAG(bs->flags, BFD_SESS_FLAG_MH))
 		vty_out(vty, "\t\tMinimum TTL: %d\n", bs->mh_ttl);
-
 	vty_out(vty, "\t\tStatus: ");
 	switch (bs->ses_state) {
 	case PTM_BFD_ADM_DOWN:
@@ -289,6 +290,8 @@ static struct json_object *__display_peer_json(struct bfd_session *bs)
 	json_object_int_add(jo, "remote-id", bs->discrs.remote_discr);
 	json_object_boolean_add(jo, "passive-mode",
 				CHECK_FLAG(bs->flags, BFD_SESS_FLAG_PASSIVE));
+	json_object_boolean_add(jo, "log-session-changes",
+				CHECK_FLAG(bs->flags, BFD_SESS_FLAG_LOG_SESSION_CHANGES));
 	if (CHECK_FLAG(bs->flags, BFD_SESS_FLAG_MH))
 		json_object_int_add(jo, "minimum-ttl", bs->mh_ttl);
 
@@ -1194,6 +1197,7 @@ static int bfd_configure_peer(struct bfd_peer_cfg *bpc, bool mhop,
 
 	/* Defaults */
 	bpc->bpc_shutdown = false;
+	bpc->bpc_log_session_changes = false;
 	bpc->bpc_detectmultiplier = BPC_DEF_DETECTMULTIPLIER;
 	bpc->bpc_recvinterval = BPC_DEF_RECEIVEINTERVAL;
 	bpc->bpc_txinterval = BPC_DEF_TRANSMITINTERVAL;
diff --git a/bfdd/dplane.c b/bfdd/dplane.c
index b1a32fb150..7269b319a3 100644
--- a/bfdd/dplane.c
+++ b/bfdd/dplane.c
@@ -384,10 +384,15 @@ bfd_dplane_session_state_change(struct bfd_dplane_ctx *bdc,
 		break;
 	}
 
-	if (bglobal.debug_peer_event)
+	if (bglobal.debug_peer_event) {
 		zlog_debug("state-change: [data plane: %s] %s -> %s",
 			   bs_to_string(bs), state_list[old_state].str,
 			   state_list[bs->ses_state].str);
+		if (CHECK_FLAG(bs->flags, BFD_SESS_FLAG_LOG_SESSION_CHANGES) &&
+		    old_state != bs->ses_state)
+			zlog_notice("Session-Change: [data plane: %s] %s -> %s", bs_to_string(bs),
+				    state_list[old_state].str, state_list[bs->ses_state].str);
+	}
 }
 
 /**