ospfd: Add Label Manager for Segment Routing

Segment Routing Global Block is now using the Label Manager to reserved
label range. Label Manager connection uses the synchronous mode and dedicated
thread timer is used to establish the connection in safe manner without
blocking OSPFd is the Label Manager is not available.

Signed-off-by: Olivier Dugeon <olivier.dugeon@orange.com>

1 files changed, 174 insertions, 92 deletions

diff --git a/ospfd/ospf_sr.c b/ospfd/ospf_sr.c
index f2330d6bd..5cc05e672 100644
--- a/ospfd/ospf_sr.c
+++ b/ospfd/ospf_sr.c
@@ -82,6 +82,7 @@
 static struct ospf_sr_db OspfSR;
 static void ospf_sr_register_vty(void);
 static inline void del_adj_sid(struct sr_nhlfe nhlfe);
+static int ospf_sr_start(struct ospf *ospf);
 
 /*
  * Segment Routing Data Base functions
@@ -221,6 +222,26 @@ static struct sr_node *get_sr_node_by_nexthop(struct ospf *ospf,
  * Segment Routing Initialization functions
  */
 
+/**
+ * Thread function to re-attempt connection to the Label Manager and thus be
+ * able to start Segment Routing.
+ *
+ * @param start		Thread structure that contains area as argument
+ *
+ * @return		1 on success
+ */
+static int sr_start_label_manager(struct thread *start)
+{
+	struct ospf *ospf;
+
+	ospf = THREAD_ARG(start);
+
+	/* re-attempt to start SR & Label Manager connection */
+	ospf_sr_start(ospf);
+
+	return 1;
+}
+
 /* Segment Routing starter function */
 static int ospf_sr_start(struct ospf *ospf)
 {
@@ -231,16 +252,56 @@ static int ospf_sr_start(struct ospf *ospf)
 
 	osr_debug("SR (%s): Start Segment Routing", __func__);
 
-	/* Initialize self SR Node */
-	srn = hash_get(OspfSR.neighbors, (void *)&(ospf->router_id),
-		       (void *)sr_node_new);
+	/* Initialize self SR Node if not already done */
+	if (OspfSR.self == NULL) {
+		srn = hash_get(OspfSR.neighbors, (void *)&(ospf->router_id),
+			       (void *)sr_node_new);
+
+		/* Complete & Store self SR Node */
+		srn->srgb.range_size = OspfSR.srgb.range_size;
+		srn->srgb.lower_bound = OspfSR.srgb.lower_bound;
+		srn->algo[0] = OspfSR.algo[0];
+		srn->msd = OspfSR.msd;
+		OspfSR.self = srn;
+	}
+
+	/* Then, start Label Manager if not ready */
+	if (!ospf_zebra_label_manager_ready())
+		if (ospf_zebra_label_manager_connect() < 0) {
+			/* Re-attempt to connect to Label Manager in 1 sec. */
+			thread_add_timer(master, sr_start_label_manager, ospf,
+					 1, &OspfSR.t_start_lm);
+			osr_debug("  |- Failed to start the Label Manager");
+			return -1;
+		}
+
+	/*
+	 * Request SGRB to the label manager if not already active. If the
+	 * allocation fails, return an error to disable SR until a new SRGB
+	 * is successfully allocated.
+	 */
+	if (!OspfSR.srgb_reserved) {
+		if (ospf_zebra_request_label_range(OspfSR.srgb.lower_bound,
+						   OspfSR.srgb.range_size)
+		    < 0) {
+			OspfSR.srgb_reserved = false;
+			return -1;
+		} else
+			OspfSR.srgb_reserved = true;
+	}
 
-	/* Complete & Store self SR Node */
-	srn->srgb.range_size = OspfSR.srgb.range_size;
-	srn->srgb.lower_bound = OspfSR.srgb.lower_bound;
-	srn->algo[0] = OspfSR.algo[0];
-	srn->msd = OspfSR.msd;
-	OspfSR.self = srn;
+	/* SR is UP and ready to flood LSA */
+	OspfSR.status = SR_UP;
+
+	/* Set Router Information SR parameters */
+	osr_debug("SR: Activate SR for Router Information LSA");
+
+	ospf_router_info_update_sr(true, OspfSR.srgb, OspfSR.msd);
+
+	/* Update Ext LSA */
+	osr_debug("SR: Activate SR for Extended Link/Prefix LSA");
+
+	ospf_ext_update_sr(true);
 
 	osr_debug("SR (%s): Update SR-DB from LSDB", __func__);
 
@@ -277,13 +338,24 @@ static void ospf_sr_stop(void)
 
 	osr_debug("SR (%s): Stop Segment Routing", __func__);
 
+	/* Disable any re-attempt to connect to Label Manager */
+	THREAD_TIMER_OFF(OspfSR.t_start_lm);
+
+	/* Release SRGB if active. */
+	if (OspfSR.srgb_reserved) {
+		ospf_zebra_release_label_range(
+			OspfSR.srgb.lower_bound,
+			OspfSR.srgb.lower_bound + OspfSR.srgb.range_size - 1);
+		OspfSR.srgb_reserved = false;
+	}
+
 	/*
 	 * Remove all SR Nodes from the Hash table. Prefix and Link SID will
 	 * be remove though list_delete() call. See sr_node_del()
 	 */
 	hash_clean(OspfSR.neighbors, (void *)sr_node_del);
 	OspfSR.self = NULL;
-	OspfSR.enabled = false;
+	OspfSR.status = SR_OFF;
 }
 
 /*
@@ -300,7 +372,7 @@ int ospf_sr_init(void)
 	osr_debug("SR (%s): Initialize SR Data Base", __func__);
 
 	memset(&OspfSR, 0, sizeof(struct ospf_sr_db));
-	OspfSR.enabled = false;
+	OspfSR.status = SR_OFF;
 	/* Only AREA flooding is supported in this release */
 	OspfSR.scope = OSPF_OPAQUE_AREA_LSA;
 
@@ -312,6 +384,7 @@ int ospf_sr_init(void)
 
 	OspfSR.srgb.range_size = MPLS_DEFAULT_MAX_SRGB_SIZE;
 	OspfSR.srgb.lower_bound = MPLS_DEFAULT_MIN_SRGB_LABEL;
+	OspfSR.srgb_reserved = false;
 	OspfSR.msd = 0;
 
 	/* Initialize Hash table for neighbor SR nodes */
@@ -1612,7 +1685,7 @@ void ospf_sr_config_write_router(struct vty *vty)
 	struct listnode *node;
 	struct sr_prefix *srp;
 
-	if (OspfSR.enabled) {
+	if (OspfSR.status != SR_OFF) {
 		vty_out(vty, " segment-routing on\n");
 
 		if ((OspfSR.srgb.lower_bound != MPLS_DEFAULT_MIN_SRGB_LABEL)
@@ -1651,7 +1724,7 @@ DEFUN(ospf_sr_enable,
 
 	VTY_DECLVAR_INSTANCE_CONTEXT(ospf, ospf);
 
-	if (OspfSR.enabled)
+	if (OspfSR.status != SR_OFF)
 		return CMD_SUCCESS;
 
 	if (ospf->vrf_id != VRF_DEFAULT) {
@@ -1663,19 +1736,9 @@ DEFUN(ospf_sr_enable,
 	osr_debug("SR: Segment Routing: OFF -> ON");
 
 	/* Start Segment Routing */
-	OspfSR.enabled = true;
+	OspfSR.status = SR_ON;
 	ospf_sr_start(ospf);
 
-	/* Set Router Information SR parameters */
-	osr_debug("SR: Activate SR for Router Information LSA");
-
-	ospf_router_info_update_sr(true, OspfSR.srgb, OspfSR.msd);
-
-	/* Update Ext LSA */
-	osr_debug("SR: Activate SR for Extended Link/Prefix LSA");
-
-	ospf_ext_update_sr(true);
-
 	return CMD_SUCCESS;
 }
 
@@ -1687,7 +1750,7 @@ DEFUN (no_ospf_sr_enable,
        "Disable Segment Routing\n")
 {
 
-	if (!OspfSR.enabled)
+	if (OspfSR.status == SR_OFF)
 		return CMD_SUCCESS;
 
 	osr_debug("SR: Segment Routing: ON -> OFF");
@@ -1706,7 +1769,7 @@ DEFUN (no_ospf_sr_enable,
 
 static int ospf_sr_enabled(struct vty *vty)
 {
-	if (OspfSR.enabled)
+	if (OspfSR.status != SR_OFF)
 		return 1;
 
 	if (vty)
@@ -1715,13 +1778,71 @@ static int ospf_sr_enabled(struct vty *vty)
 	return 0;
 }
 
+/**
+ * Update SRGB following new CLI value.
+ *
+ * @param lower	Lower bound of the SRGB
+ * @param size	Size of the SRGB
+ *
+ * @return	0 on success, -1 otherwise
+ */
+static int update_srgb(uint32_t lower, uint32_t size)
+{
+
+	/* Check if values have changed */
+	if ((OspfSR.srgb.range_size == size)
+	    && (OspfSR.srgb.lower_bound == lower))
+		return 0;
+
+	/* Release old SRGB if active. */
+	if (OspfSR.srgb_reserved) {
+		ospf_zebra_release_label_range(
+			OspfSR.srgb.lower_bound,
+			OspfSR.srgb.lower_bound + OspfSR.srgb.range_size - 1);
+		OspfSR.srgb_reserved = false;
+	}
+
+	/* Set new SRGB values */
+	OspfSR.srgb.range_size = size;
+	OspfSR.srgb.lower_bound = lower;
+	if (OspfSR.self != NULL) {
+		OspfSR.self->srgb.range_size = size;
+		OspfSR.self->srgb.lower_bound = lower;
+	}
+
+	/* Check if SR is correctly started i.e. Label Manager connected */
+	if (OspfSR.status != SR_UP)
+		return 0;
+
+	/*
+	 * Try to reserve the new block from the Label Manger. If the allocation
+	 * fails, disable SR until a new SRGB is successfully allocated.
+	 */
+	if (ospf_zebra_request_label_range(OspfSR.srgb.lower_bound,
+					   OspfSR.srgb.range_size) < 0) {
+		OspfSR.srgb_reserved = false;
+		ospf_sr_stop();
+		return -1;
+	}
+
+	/* SRGB is reserved, set Router Information parameters */
+	ospf_router_info_update_sr(true, OspfSR.srgb, OspfSR.msd);
+
+	/* and update NHLFE entries */
+	hash_iterate(OspfSR.neighbors,
+		     (void (*)(struct hash_bucket *, void *))update_in_nhlfe,
+		     NULL);
+
+	return 0;
+}
+
 DEFUN (sr_sid_label_range,
        sr_sid_label_range_cmd,
-       "segment-routing global-block (0-1048575) (0-1048575)",
+       "segment-routing global-block (16-1048575) (16-1048575)",
        SR_STR
        "Segment Routing Global Block label range\n"
-       "Lower-bound range in decimal (0-1048575)\n"
-       "Upper-bound range in decimal (0-1048575)\n")
+       "Lower-bound range in decimal (16-1048575)\n"
+       "Upper-bound range in decimal (16-1048575)\n")
 {
 	uint32_t upper;
 	uint32_t lower;
@@ -1737,47 +1858,10 @@ DEFUN (sr_sid_label_range,
 	upper = strtoul(argv[idx_up]->arg, NULL, 10);
 	size = upper - lower + 1;
 
-	if (size > MPLS_DEFAULT_MAX_SRGB_SIZE || size <= 0) {
-		vty_out(vty,
-			"Range size cannot be less than 0 or more than %u\n",
-			MPLS_DEFAULT_MAX_SRGB_SIZE);
-		return CMD_WARNING_CONFIG_FAILED;
-	}
-
-	if (upper > MPLS_DEFAULT_MAX_SRGB_LABEL) {
-		vty_out(vty, "Upper-bound cannot exceed %u\n",
-			MPLS_DEFAULT_MAX_SRGB_LABEL);
+	if (update_srgb(lower, size) < 0)
 		return CMD_WARNING_CONFIG_FAILED;
-	}
-
-	if (upper < MPLS_DEFAULT_MIN_SRGB_LABEL) {
-		vty_out(vty, "Upper-bound cannot be lower than %u\n",
-			MPLS_DEFAULT_MIN_SRGB_LABEL);
-		return CMD_WARNING_CONFIG_FAILED;
-	}
-
-	/* Check if values have changed */
-	if ((OspfSR.srgb.range_size == size)
-	    && (OspfSR.srgb.lower_bound == lower))
+	else
 		return CMD_SUCCESS;
-
-	/* Set SID/Label range SRGB */
-	OspfSR.srgb.range_size = size;
-	OspfSR.srgb.lower_bound = lower;
-	if (OspfSR.self != NULL) {
-		OspfSR.self->srgb.range_size = size;
-		OspfSR.self->srgb.lower_bound = lower;
-	}
-
-	/* Set Router Information SR parameters */
-	ospf_router_info_update_sr(true, OspfSR.srgb, OspfSR.msd);
-
-	/* Update NHLFE entries */
-	hash_iterate(OspfSR.neighbors,
-		     (void (*)(struct hash_bucket *, void *))update_in_nhlfe,
-		     NULL);
-
-	return CMD_SUCCESS;
 }
 
 DEFUN (no_sr_sid_label_range,
@@ -1793,23 +1877,11 @@ DEFUN (no_sr_sid_label_range,
 	if (!ospf_sr_enabled(vty))
 		return CMD_WARNING_CONFIG_FAILED;
 
-	/* Revert to default SRGB value */
-	OspfSR.srgb.range_size = MPLS_DEFAULT_MIN_SRGB_SIZE;
-	OspfSR.srgb.lower_bound = MPLS_DEFAULT_MIN_SRGB_LABEL;
-	if (OspfSR.self != NULL) {
-		OspfSR.self->srgb.range_size = OspfSR.srgb.range_size;
-		OspfSR.self->srgb.lower_bound = OspfSR.srgb.lower_bound;
-	}
-
-	/* Set Router Information SR parameters */
-	ospf_router_info_update_sr(true, OspfSR.srgb, OspfSR.msd);
-
-	/* Update NHLFE entries */
-	hash_iterate(OspfSR.neighbors,
-		     (void (*)(struct hash_bucket *, void *))update_in_nhlfe,
-		     NULL);
-
-	return CMD_SUCCESS;
+	if (update_srgb(MPLS_DEFAULT_MIN_SRGB_SIZE,
+			MPLS_DEFAULT_MIN_SRGB_LABEL) < 0)
+		return CMD_WARNING_CONFIG_FAILED;
+	else
+		return CMD_SUCCESS;
 }
 
 DEFUN (sr_node_msd,
@@ -1843,8 +1915,9 @@ DEFUN (sr_node_msd,
 	if (OspfSR.self != NULL)
 		OspfSR.self->msd = msd;
 
-	/* Set Router Information SR parameters */
-	ospf_router_info_update_sr(true, OspfSR.srgb, OspfSR.msd);
+	/* Set Router Information parameters if SR is UP */
+	if (OspfSR.status == SR_UP)
+		ospf_router_info_update_sr(true, OspfSR.srgb, OspfSR.msd);
 
 	return CMD_SUCCESS;
 }
@@ -1866,8 +1939,9 @@ DEFUN (no_sr_node_msd,
 	if (OspfSR.self != NULL)
 		OspfSR.self->msd = 0;
 
-	/* Set Router Information SR parameters */
-	ospf_router_info_update_sr(true, OspfSR.srgb, 0);
+	/* Set Router Information parameters if SR is UP */
+	if (OspfSR.status == SR_UP)
+		ospf_router_info_update_sr(true, OspfSR.srgb, 0);
 
 	return CMD_SUCCESS;
 }
@@ -1972,9 +2046,14 @@ DEFUN (sr_prefix_sid,
 	} else {
 		listnode_add(OspfSR.self->ext_prefix, new);
 	}
-	ospf_zebra_update_prefix_sid(new);
 
-	/* Finally, update Extended Prefix LSA */
+	/* Install Prefix SID if SR is UP */
+	if (OspfSR.status == SR_UP)
+		ospf_zebra_update_prefix_sid(new);
+	else
+		return CMD_SUCCESS;
+
+	/* Finally, update Extended Prefix LSA id SR is UP */
 	new->instance = ospf_ext_schedule_prefix_index(
 		ifp, new->sid, &new->prefv4, new->flags);
 	if (new->instance == 0) {
@@ -2008,6 +2087,9 @@ DEFUN (no_sr_prefix_sid,
 	if (!ospf_sr_enabled(vty))
 		return CMD_WARNING_CONFIG_FAILED;
 
+	if (OspfSR.status != SR_UP)
+		return CMD_SUCCESS;
+
 	/* Get network prefix */
 	argv_find(argv, argc, "A.B.C.D/M", &idx);
 	rc = str2prefix(argv[idx]->arg, &p);
@@ -2352,7 +2434,7 @@ DEFUN (show_ip_opsf_srdb,
 	bool uj = use_json(argc, argv);
 	json_object *json = NULL, *json_node_array = NULL;
 
-	if (!OspfSR.enabled) {
+	if (OspfSR.status == SR_OFF) {
 		vty_out(vty, "Segment Routing is disabled on this router\n");
 		return CMD_WARNING;
 	}