1 files changed, 389 insertions, 0 deletions

diff --git a/zebra/zebra_srte.c b/zebra/zebra_srte.c
new file mode 100644
index 0000000..c0f18dd
--- /dev/null
+++ b/zebra/zebra_srte.c
@@ -0,0 +1,389 @@
+/* Zebra SR-TE code
+ * Copyright (C) 2020  NetDEF, Inc.
+ *
+ * This file is part of GNU Zebra.
+ *
+ * GNU Zebra is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2, or (at your option) any
+ * later version.
+ *
+ * GNU Zebra is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; see the file COPYING; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <zebra.h>
+
+#include "lib/zclient.h"
+#include "lib/lib_errors.h"
+
+#include "zebra/zebra_srte.h"
+#include "zebra/zebra_mpls.h"
+#include "zebra/zebra_rnh.h"
+#include "zebra/zapi_msg.h"
+
+DEFINE_MTYPE_STATIC(ZEBRA, ZEBRA_SR_POLICY, "SR Policy");
+
+static void zebra_sr_policy_deactivate(struct zebra_sr_policy *policy);
+
+/* Generate rb-tree of SR Policy instances. */
+static inline int
+zebra_sr_policy_instance_compare(const struct zebra_sr_policy *a,
+				 const struct zebra_sr_policy *b)
+{
+	return sr_policy_compare(&a->endpoint, &b->endpoint, a->color,
+				 b->color);
+}
+RB_GENERATE(zebra_sr_policy_instance_head, zebra_sr_policy, entry,
+	    zebra_sr_policy_instance_compare)
+
+struct zebra_sr_policy_instance_head zebra_sr_policy_instances =
+	RB_INITIALIZER(&zebra_sr_policy_instances);
+
+struct zebra_sr_policy *zebra_sr_policy_add(uint32_t color,
+					    struct ipaddr *endpoint, char *name)
+{
+	struct zebra_sr_policy *policy;
+
+	policy = XCALLOC(MTYPE_ZEBRA_SR_POLICY, sizeof(*policy));
+	policy->color = color;
+	policy->endpoint = *endpoint;
+	strlcpy(policy->name, name, sizeof(policy->name));
+	policy->status = ZEBRA_SR_POLICY_DOWN;
+	RB_INSERT(zebra_sr_policy_instance_head, &zebra_sr_policy_instances,
+		  policy);
+
+	return policy;
+}
+
+void zebra_sr_policy_del(struct zebra_sr_policy *policy)
+{
+	if (policy->status == ZEBRA_SR_POLICY_UP)
+		zebra_sr_policy_deactivate(policy);
+	RB_REMOVE(zebra_sr_policy_instance_head, &zebra_sr_policy_instances,
+		  policy);
+	XFREE(MTYPE_ZEBRA_SR_POLICY, policy);
+}
+
+struct zebra_sr_policy *zebra_sr_policy_find(uint32_t color,
+					     struct ipaddr *endpoint)
+{
+	struct zebra_sr_policy policy = {};
+
+	policy.color = color;
+	policy.endpoint = *endpoint;
+	return RB_FIND(zebra_sr_policy_instance_head,
+		       &zebra_sr_policy_instances, &policy);
+}
+
+struct zebra_sr_policy *zebra_sr_policy_find_by_name(char *name)
+{
+	struct zebra_sr_policy *policy;
+
+	// TODO: create index for policy names
+	RB_FOREACH (policy, zebra_sr_policy_instance_head,
+		    &zebra_sr_policy_instances) {
+		if (strcmp(policy->name, name) == 0)
+			return policy;
+	}
+
+	return NULL;
+}
+
+static int zebra_sr_policy_notify_update_client(struct zebra_sr_policy *policy,
+						struct zserv *client)
+{
+	const struct zebra_nhlfe *nhlfe;
+	struct stream *s;
+	uint32_t message = 0;
+	unsigned long nump = 0;
+	uint8_t num;
+	struct zapi_nexthop znh;
+	int ret;
+
+	/* Get output stream. */
+	s = stream_new(ZEBRA_MAX_PACKET_SIZ);
+
+	zclient_create_header(s, ZEBRA_NEXTHOP_UPDATE, zvrf_id(policy->zvrf));
+
+	/* Message flags. */
+	SET_FLAG(message, ZAPI_MESSAGE_SRTE);
+	stream_putl(s, message);
+
+	stream_putw(s, SAFI_UNICAST);
+	/*
+	 * The prefix is copied twice because the ZEBRA_NEXTHOP_UPDATE
+	 * code was modified to send back both the matched against
+	 * as well as the actual matched.  There does not appear to
+	 * be an equivalent here so just send the same thing twice.
+	 */
+	switch (policy->endpoint.ipa_type) {
+	case IPADDR_V4:
+		stream_putw(s, AF_INET);
+		stream_putc(s, IPV4_MAX_BITLEN);
+		stream_put_in_addr(s, &policy->endpoint.ipaddr_v4);
+		stream_putw(s, AF_INET);
+		stream_putc(s, IPV4_MAX_BITLEN);
+		stream_put_in_addr(s, &policy->endpoint.ipaddr_v4);
+		break;
+	case IPADDR_V6:
+		stream_putw(s, AF_INET6);
+		stream_putc(s, IPV6_MAX_BITLEN);
+		stream_put(s, &policy->endpoint.ipaddr_v6, IPV6_MAX_BYTELEN);
+		stream_putw(s, AF_INET6);
+		stream_putc(s, IPV6_MAX_BITLEN);
+		stream_put(s, &policy->endpoint.ipaddr_v6, IPV6_MAX_BYTELEN);
+		break;
+	default:
+		flog_warn(EC_LIB_DEVELOPMENT,
+			  "%s: unknown policy endpoint address family: %u",
+			  __func__, policy->endpoint.ipa_type);
+		exit(1);
+	}
+	stream_putl(s, policy->color);
+
+	num = 0;
+	frr_each (nhlfe_list_const, &policy->lsp->nhlfe_list, nhlfe) {
+		if (!CHECK_FLAG(nhlfe->flags, NHLFE_FLAG_SELECTED)
+		    || CHECK_FLAG(nhlfe->flags, NHLFE_FLAG_DELETED))
+			continue;
+
+		if (num == 0) {
+			stream_putc(s, re_type_from_lsp_type(nhlfe->type));
+			stream_putw(s, 0); /* instance - not available */
+			stream_putc(s, nhlfe->distance);
+			stream_putl(s, 0); /* metric - not available */
+			nump = stream_get_endp(s);
+			stream_putc(s, 0);
+		}
+
+		zapi_nexthop_from_nexthop(&znh, nhlfe->nexthop);
+		ret = zapi_nexthop_encode(s, &znh, 0, message);
+		if (ret < 0)
+			goto failure;
+
+		num++;
+	}
+	stream_putc_at(s, nump, num);
+	stream_putw_at(s, 0, stream_get_endp(s));
+
+	client->nh_last_upd_time = monotime(NULL);
+	return zserv_send_message(client, s);
+
+failure:
+
+	stream_free(s);
+	return -1;
+}
+
+static void zebra_sr_policy_notify_update(struct zebra_sr_policy *policy)
+{
+	struct rnh *rnh;
+	struct prefix p = {};
+	struct zebra_vrf *zvrf;
+	struct listnode *node;
+	struct zserv *client;
+
+	zvrf = policy->zvrf;
+	switch (policy->endpoint.ipa_type) {
+	case IPADDR_V4:
+		p.family = AF_INET;
+		p.prefixlen = IPV4_MAX_BITLEN;
+		p.u.prefix4 = policy->endpoint.ipaddr_v4;
+		break;
+	case IPADDR_V6:
+		p.family = AF_INET6;
+		p.prefixlen = IPV6_MAX_BITLEN;
+		p.u.prefix6 = policy->endpoint.ipaddr_v6;
+		break;
+	default:
+		flog_warn(EC_LIB_DEVELOPMENT,
+			  "%s: unknown policy endpoint address family: %u",
+			  __func__, policy->endpoint.ipa_type);
+		exit(1);
+	}
+
+	rnh = zebra_lookup_rnh(&p, zvrf_id(zvrf), SAFI_UNICAST);
+	if (!rnh)
+		return;
+
+	for (ALL_LIST_ELEMENTS_RO(rnh->client_list, node, client)) {
+		if (policy->status == ZEBRA_SR_POLICY_UP)
+			zebra_sr_policy_notify_update_client(policy, client);
+		else
+			/* Fallback to the IGP shortest path. */
+			zebra_send_rnh_update(rnh, client, zvrf_id(zvrf),
+					      policy->color);
+	}
+}
+
+static void zebra_sr_policy_activate(struct zebra_sr_policy *policy,
+				     struct zebra_lsp *lsp)
+{
+	policy->status = ZEBRA_SR_POLICY_UP;
+	policy->lsp = lsp;
+	(void)zebra_sr_policy_bsid_install(policy);
+	zsend_sr_policy_notify_status(policy->color, &policy->endpoint,
+				      policy->name, ZEBRA_SR_POLICY_UP);
+	zebra_sr_policy_notify_update(policy);
+}
+
+static void zebra_sr_policy_update(struct zebra_sr_policy *policy,
+				   struct zebra_lsp *lsp,
+				   struct zapi_srte_tunnel *old_tunnel)
+{
+	bool bsid_changed;
+	bool segment_list_changed;
+
+	policy->lsp = lsp;
+
+	bsid_changed =
+		policy->segment_list.local_label != old_tunnel->local_label;
+	segment_list_changed =
+		policy->segment_list.label_num != old_tunnel->label_num
+		|| memcmp(policy->segment_list.labels, old_tunnel->labels,
+			  sizeof(mpls_label_t)
+				  * policy->segment_list.label_num);
+
+	/* Re-install label stack if necessary. */
+	if (bsid_changed || segment_list_changed) {
+		zebra_sr_policy_bsid_uninstall(policy, old_tunnel->local_label);
+		(void)zebra_sr_policy_bsid_install(policy);
+	}
+
+	zsend_sr_policy_notify_status(policy->color, &policy->endpoint,
+				      policy->name, ZEBRA_SR_POLICY_UP);
+
+	/* Handle segment-list update. */
+	if (segment_list_changed)
+		zebra_sr_policy_notify_update(policy);
+}
+
+static void zebra_sr_policy_deactivate(struct zebra_sr_policy *policy)
+{
+	policy->status = ZEBRA_SR_POLICY_DOWN;
+	policy->lsp = NULL;
+	zebra_sr_policy_bsid_uninstall(policy,
+				       policy->segment_list.local_label);
+	zsend_sr_policy_notify_status(policy->color, &policy->endpoint,
+				      policy->name, ZEBRA_SR_POLICY_DOWN);
+	zebra_sr_policy_notify_update(policy);
+}
+
+int zebra_sr_policy_validate(struct zebra_sr_policy *policy,
+			     struct zapi_srte_tunnel *new_tunnel)
+{
+	struct zapi_srte_tunnel old_tunnel = policy->segment_list;
+	struct zebra_lsp *lsp;
+
+	if (new_tunnel)
+		policy->segment_list = *new_tunnel;
+
+	/* Try to resolve the Binding-SID nexthops. */
+	lsp = mpls_lsp_find(policy->zvrf, policy->segment_list.labels[0]);
+	if (!lsp || !lsp->best_nhlfe
+	    || lsp->addr_family != ipaddr_family(&policy->endpoint)) {
+		if (policy->status == ZEBRA_SR_POLICY_UP)
+			zebra_sr_policy_deactivate(policy);
+		return -1;
+	}
+
+	/* First label was resolved successfully. */
+	if (policy->status == ZEBRA_SR_POLICY_DOWN)
+		zebra_sr_policy_activate(policy, lsp);
+	else
+		zebra_sr_policy_update(policy, lsp, &old_tunnel);
+
+	return 0;
+}
+
+int zebra_sr_policy_bsid_install(struct zebra_sr_policy *policy)
+{
+	struct zapi_srte_tunnel *zt = &policy->segment_list;
+	struct zebra_nhlfe *nhlfe;
+
+	if (zt->local_label == MPLS_LABEL_NONE)
+		return 0;
+
+	frr_each_safe (nhlfe_list, &policy->lsp->nhlfe_list, nhlfe) {
+		uint8_t num_out_labels;
+		mpls_label_t *out_labels;
+		mpls_label_t null_label = MPLS_LABEL_IMPLICIT_NULL;
+
+		if (!CHECK_FLAG(nhlfe->flags, NHLFE_FLAG_SELECTED)
+		    || CHECK_FLAG(nhlfe->flags, NHLFE_FLAG_DELETED))
+			continue;
+
+		/*
+		 * Don't push the first SID if the corresponding action in the
+		 * LFIB is POP.
+		 */
+		if (!nhlfe->nexthop->nh_label
+		    || !nhlfe->nexthop->nh_label->num_labels
+		    || nhlfe->nexthop->nh_label->label[0]
+			       == MPLS_LABEL_IMPLICIT_NULL) {
+			if (zt->label_num > 1) {
+				num_out_labels = zt->label_num - 1;
+				out_labels = &zt->labels[1];
+			} else {
+				num_out_labels = 1;
+				out_labels = &null_label;
+			}
+		} else {
+			num_out_labels = zt->label_num;
+			out_labels = zt->labels;
+		}
+
+		if (mpls_lsp_install(
+			    policy->zvrf, zt->type, zt->local_label,
+			    num_out_labels, out_labels, nhlfe->nexthop->type,
+			    &nhlfe->nexthop->gate, nhlfe->nexthop->ifindex)
+		    < 0)
+			return -1;
+	}
+
+	return 0;
+}
+
+void zebra_sr_policy_bsid_uninstall(struct zebra_sr_policy *policy,
+				    mpls_label_t old_bsid)
+{
+	struct zapi_srte_tunnel *zt = &policy->segment_list;
+
+	mpls_lsp_uninstall_all_vrf(policy->zvrf, zt->type, old_bsid);
+}
+
+int zebra_sr_policy_label_update(mpls_label_t label,
+				 enum zebra_sr_policy_update_label_mode mode)
+{
+	struct zebra_sr_policy *policy;
+
+	RB_FOREACH (policy, zebra_sr_policy_instance_head,
+		    &zebra_sr_policy_instances) {
+		mpls_label_t next_hop_label;
+
+		next_hop_label = policy->segment_list.labels[0];
+		if (next_hop_label != label)
+			continue;
+
+		switch (mode) {
+		case ZEBRA_SR_POLICY_LABEL_CREATED:
+		case ZEBRA_SR_POLICY_LABEL_UPDATED:
+		case ZEBRA_SR_POLICY_LABEL_REMOVED:
+			zebra_sr_policy_validate(policy, NULL);
+			break;
+		}
+	}
+
+	return 0;
+}
+
+void zebra_srte_init(void)
+{
+}