isisd: add support for segment routing

This is an implementation of the IS-IS SR draft [1] for FRR.

The following features are supported:
* IPv4 and IPv6 Prefix-SIDs;
* IPv4 and IPv6 Adj-SIDs and LAN-Adj-SIDs;
* Index and absolute labels;
* The no-php and explicit-null Prefix-SID flags;
* Full integration with the Label Manager.

Known limitations:
* No support for Anycast-SIDs;
* No support for the SID/Label Binding TLV (required for LDP interop).
* No support for persistent Adj-SIDs;
* No support for multiple SRGBs.

[1] draft-ietf-isis-segment-routing-extensions-25

Signed-off-by: Olivier Dugeon <olivier.dugeon@orange.com>
Signed-off-by: Renato Westphal <renato@opensourcerouting.org>

1 files changed, 178 insertions, 84 deletions

diff --git a/isisd/isis_nb_config.c b/isisd/isis_nb_config.c
index f97202c9a..ec3b7baa3 100644
--- a/isisd/isis_nb_config.c
+++ b/isisd/isis_nb_config.c
@@ -1405,35 +1405,78 @@ int isis_instance_mpls_te_router_address_destroy(
 /*
  * XPath: /frr-isisd:isis/instance/segment-routing/enabled
  */
-int isis_instance_segment_routing_enabled_modify(enum nb_event event,
-						 const struct lyd_node *dnode,
-						 union nb_resource *resource)
+int isis_instance_segment_routing_enabled_modify(
+	struct nb_cb_modify_args *args)
 {
-	switch (event) {
-	case NB_EV_VALIDATE:
-	case NB_EV_PREPARE:
-	case NB_EV_ABORT:
-	case NB_EV_APPLY:
-		/* TODO: implement me. */
-		break;
+	struct isis_area *area;
+
+	if (args->event != NB_EV_APPLY)
+		return NB_OK;
+
+	area = nb_running_get_entry(args->dnode, NULL, true);
+	area->srdb.config.enabled = yang_dnode_get_bool(args->dnode, NULL);
+
+	if (area->srdb.config.enabled) {
+		if (IS_DEBUG_ISIS(DEBUG_EVENTS))
+			zlog_debug("SR: Segment Routing: OFF -> ON");
+
+		if (isis_sr_start(area) == 0)
+			area->srdb.enabled = true;
+	} else {
+		if (IS_DEBUG_ISIS(DEBUG_EVENTS))
+			zlog_debug("SR: Segment Routing: ON -> OFF");
+
+		isis_sr_stop(area);
+		area->srdb.enabled = false;
 	}
 
 	return NB_OK;
 }
 
 /*
+ * XPath: /frr-isisd:isis/instance/segment-routing/srgb
+ */
+void isis_instance_segment_routing_srgb_apply_finish(
+	struct nb_cb_apply_finish_args *args)
+{
+	struct isis_area *area;
+	uint32_t lower_bound, upper_bound;
+	int ret;
+
+	area = nb_running_get_entry(args->dnode, NULL, true);
+	lower_bound = yang_dnode_get_uint32(args->dnode, "./lower-bound");
+	upper_bound = yang_dnode_get_uint32(args->dnode, "./upper-bound");
+
+	ret = isis_sr_cfg_srgb_update(area, lower_bound, upper_bound);
+	if (area->srdb.config.enabled) {
+		if (ret == 0)
+			area->srdb.enabled = true;
+		else {
+			isis_sr_stop(area);
+			area->srdb.enabled = false;
+		}
+	}
+}
+
+/*
  * XPath: /frr-isisd:isis/instance/segment-routing/srgb/lower-bound
  */
 int isis_instance_segment_routing_srgb_lower_bound_modify(
-	enum nb_event event, const struct lyd_node *dnode,
-	union nb_resource *resource)
+	struct nb_cb_modify_args *args)
 {
-	switch (event) {
+	uint32_t lower_bound = yang_dnode_get_uint32(args->dnode, NULL);
+
+	switch (args->event) {
 	case NB_EV_VALIDATE:
+		if (!IS_MPLS_UNRESERVED_LABEL(lower_bound)) {
+			zlog_warn("Invalid SRGB lower bound: %" PRIu32,
+				  lower_bound);
+			return NB_ERR_VALIDATION;
+		}
+		break;
 	case NB_EV_PREPARE:
 	case NB_EV_ABORT:
 	case NB_EV_APPLY:
-		/* TODO: implement me. */
 		break;
 	}
 
@@ -1444,15 +1487,21 @@ int isis_instance_segment_routing_srgb_lower_bound_modify(
  * XPath: /frr-isisd:isis/instance/segment-routing/srgb/upper-bound
  */
 int isis_instance_segment_routing_srgb_upper_bound_modify(
-	enum nb_event event, const struct lyd_node *dnode,
-	union nb_resource *resource)
+	struct nb_cb_modify_args *args)
 {
-	switch (event) {
+	uint32_t upper_bound = yang_dnode_get_uint32(args->dnode, NULL);
+
+	switch (args->event) {
 	case NB_EV_VALIDATE:
+		if (!IS_MPLS_UNRESERVED_LABEL(upper_bound)) {
+			zlog_warn("Invalid SRGB upper bound: %" PRIu32,
+				  upper_bound);
+			return NB_ERR_VALIDATION;
+		}
+		break;
 	case NB_EV_PREPARE:
 	case NB_EV_ABORT:
 	case NB_EV_APPLY:
-		/* TODO: implement me. */
 		break;
 	}
 
@@ -1463,32 +1512,31 @@ int isis_instance_segment_routing_srgb_upper_bound_modify(
  * XPath: /frr-isisd:isis/instance/segment-routing/msd/node-msd
  */
 int isis_instance_segment_routing_msd_node_msd_modify(
-	enum nb_event event, const struct lyd_node *dnode,
-	union nb_resource *resource)
+	struct nb_cb_modify_args *args)
 {
-	switch (event) {
-	case NB_EV_VALIDATE:
-	case NB_EV_PREPARE:
-	case NB_EV_ABORT:
-	case NB_EV_APPLY:
-		/* TODO: implement me. */
-		break;
-	}
+	struct isis_area *area;
+
+	if (args->event != NB_EV_APPLY)
+		return NB_OK;
+
+	area = nb_running_get_entry(args->dnode, NULL, true);
+	area->srdb.config.msd = yang_dnode_get_uint8(args->dnode, NULL);
+	isis_sr_cfg_msd_update(area);
 
 	return NB_OK;
 }
 
 int isis_instance_segment_routing_msd_node_msd_destroy(
-	enum nb_event event, const struct lyd_node *dnode)
+	struct nb_cb_destroy_args *args)
 {
-	switch (event) {
-	case NB_EV_VALIDATE:
-	case NB_EV_PREPARE:
-	case NB_EV_ABORT:
-	case NB_EV_APPLY:
-		/* TODO: implement me. */
-		break;
-	}
+	struct isis_area *area;
+
+	if (args->event != NB_EV_APPLY)
+		return NB_OK;
+
+	area = nb_running_get_entry(args->dnode, NULL, true);
+	area->srdb.config.msd = 0;
+	isis_sr_cfg_msd_update(area);
 
 	return NB_OK;
 }
@@ -1497,52 +1545,102 @@ int isis_instance_segment_routing_msd_node_msd_destroy(
  * XPath: /frr-isisd:isis/instance/segment-routing/prefix-sid-map/prefix-sid
  */
 int isis_instance_segment_routing_prefix_sid_map_prefix_sid_create(
-	enum nb_event event, const struct lyd_node *dnode,
-	union nb_resource *resource)
+	struct nb_cb_create_args *args)
 {
-	switch (event) {
-	case NB_EV_VALIDATE:
-	case NB_EV_PREPARE:
-	case NB_EV_ABORT:
-	case NB_EV_APPLY:
-		/* TODO: implement me. */
-		break;
-	}
+	struct isis_area *area;
+	struct prefix prefix;
+	struct sr_prefix_cfg *pcfg;
+
+	if (args->event != NB_EV_APPLY)
+		return NB_OK;
+
+	area = nb_running_get_entry(args->dnode, NULL, true);
+	yang_dnode_get_prefix(&prefix, args->dnode, "./prefix");
+
+	pcfg = isis_sr_cfg_prefix_add(area, &prefix);
+	nb_running_set_entry(args->dnode, pcfg);
 
 	return NB_OK;
 }
 
 int isis_instance_segment_routing_prefix_sid_map_prefix_sid_destroy(
-	enum nb_event event, const struct lyd_node *dnode)
+	struct nb_cb_destroy_args *args)
 {
-	switch (event) {
-	case NB_EV_VALIDATE:
-	case NB_EV_PREPARE:
-	case NB_EV_ABORT:
-	case NB_EV_APPLY:
-		/* TODO: implement me. */
+	struct sr_prefix_cfg *pcfg;
+	struct isis_area *area;
+
+	if (args->event != NB_EV_APPLY)
+		return NB_OK;
+
+	pcfg = nb_running_unset_entry(args->dnode);
+	area = pcfg->area;
+	isis_sr_cfg_prefix_del(pcfg);
+	lsp_regenerate_schedule(area, area->is_type, 0);
+
+	return NB_OK;
+}
+
+int isis_instance_segment_routing_prefix_sid_map_prefix_sid_pre_validate(
+	struct nb_cb_pre_validate_args *args)
+{
+	uint32_t srgb_lbound;
+	uint32_t srgb_ubound;
+	uint32_t srgb_range;
+	uint32_t sid;
+	enum sr_sid_value_type sid_type;
+
+	srgb_lbound = yang_dnode_get_uint32(args->dnode,
+					    "../../srgb/lower-bound");
+	srgb_ubound = yang_dnode_get_uint32(args->dnode,
+					    "../../srgb/upper-bound");
+	sid = yang_dnode_get_uint32(args->dnode, "./sid-value");
+	sid_type = yang_dnode_get_enum(args->dnode, "./sid-value-type");
+
+	srgb_range = srgb_ubound - srgb_lbound + 1;
+	switch (sid_type) {
+	case SR_SID_VALUE_TYPE_INDEX:
+		if (sid >= srgb_range) {
+			zlog_warn("SID index %u falls outside local SRGB range",
+				  sid);
+			return NB_ERR_VALIDATION;
+		}
+		break;
+	case SR_SID_VALUE_TYPE_ABSOLUTE:
+		if (!IS_MPLS_UNRESERVED_LABEL(sid)) {
+			zlog_warn("Invalid absolute SID %u", sid);
+			return NB_ERR_VALIDATION;
+		}
 		break;
 	}
 
 	return NB_OK;
 }
 
+void isis_instance_segment_routing_prefix_sid_map_prefix_sid_apply_finish(
+	struct nb_cb_apply_finish_args *args)
+{
+	struct sr_prefix_cfg *pcfg;
+	struct isis_area *area;
+
+	pcfg = nb_running_get_entry(args->dnode, NULL, true);
+	area = pcfg->area;
+	lsp_regenerate_schedule(area, area->is_type, 0);
+}
+
 /*
  * XPath:
  * /frr-isisd:isis/instance/segment-routing/prefix-sid-map/prefix-sid/sid-value-type
  */
 int isis_instance_segment_routing_prefix_sid_map_prefix_sid_sid_value_type_modify(
-	enum nb_event event, const struct lyd_node *dnode,
-	union nb_resource *resource)
+	struct nb_cb_modify_args *args)
 {
-	switch (event) {
-	case NB_EV_VALIDATE:
-	case NB_EV_PREPARE:
-	case NB_EV_ABORT:
-	case NB_EV_APPLY:
-		/* TODO: implement me. */
-		break;
-	}
+	struct sr_prefix_cfg *pcfg;
+
+	if (args->event != NB_EV_APPLY)
+		return NB_OK;
+
+	pcfg = nb_running_get_entry(args->dnode, NULL, true);
+	pcfg->sid_type = yang_dnode_get_enum(args->dnode, NULL);
 
 	return NB_OK;
 }
@@ -1552,17 +1650,15 @@ int isis_instance_segment_routing_prefix_sid_map_prefix_sid_sid_value_type_modif
  * /frr-isisd:isis/instance/segment-routing/prefix-sid-map/prefix-sid/sid-value
  */
 int isis_instance_segment_routing_prefix_sid_map_prefix_sid_sid_value_modify(
-	enum nb_event event, const struct lyd_node *dnode,
-	union nb_resource *resource)
+	struct nb_cb_modify_args *args)
 {
-	switch (event) {
-	case NB_EV_VALIDATE:
-	case NB_EV_PREPARE:
-	case NB_EV_ABORT:
-	case NB_EV_APPLY:
-		/* TODO: implement me. */
-		break;
-	}
+	struct sr_prefix_cfg *pcfg;
+
+	if (args->event != NB_EV_APPLY)
+		return NB_OK;
+
+	pcfg = nb_running_get_entry(args->dnode, NULL, true);
+	pcfg->sid = yang_dnode_get_uint32(args->dnode, NULL);
 
 	return NB_OK;
 }
@@ -1572,17 +1668,15 @@ int isis_instance_segment_routing_prefix_sid_map_prefix_sid_sid_value_modify(
  * /frr-isisd:isis/instance/segment-routing/prefix-sid-map/prefix-sid/last-hop-behavior
  */
 int isis_instance_segment_routing_prefix_sid_map_prefix_sid_last_hop_behavior_modify(
-	enum nb_event event, const struct lyd_node *dnode,
-	union nb_resource *resource)
+	struct nb_cb_modify_args *args)
 {
-	switch (event) {
-	case NB_EV_VALIDATE:
-	case NB_EV_PREPARE:
-	case NB_EV_ABORT:
-	case NB_EV_APPLY:
-		/* TODO: implement me. */
-		break;
-	}
+	struct sr_prefix_cfg *pcfg;
+
+	if (args->event != NB_EV_APPLY)
+		return NB_OK;
+
+	pcfg = nb_running_get_entry(args->dnode, NULL, true);
+	pcfg->last_hop_behavior = yang_dnode_get_enum(args->dnode, NULL);
 
 	return NB_OK;
 }