Add MPLS support

api/gr_net_types.h

@@ -27,6 +27,7 @@ typedef enum : uint8_t {
 	GR_AF_UNSPEC = AF_UNSPEC,
 	GR_AF_IP4 = AF_INET,
 	GR_AF_IP6 = AF_INET6,
+	GR_AF_MPLS = AF_MPLS,
 } addr_family_t;
 
 // Convert address family enum to string representation.
@@ -38,6 +39,8 @@ static inline const char *gr_af_name(addr_family_t af) {
 		return "ipv4";
 	case GR_AF_IP6:
 		return "ipv6";
+	case GR_AF_MPLS:
+		return "mpls";
 	}
 	return "?";
 }
@@ -48,6 +51,7 @@ static inline bool gr_af_valid(addr_family_t af) {
 	case GR_AF_UNSPEC:
 	case GR_AF_IP4:
 	case GR_AF_IP6:
+	case GR_AF_MPLS:
 		return true;
 	}
 	return false;

docs/grout-frr.7.scdoc

@@ -27,7 +27,9 @@ routes to grout, and grout notifies FRR of link and address changes.
 The following zebra dataplane operations are handled:
 
 - IPv4/IPv6 route install, update and delete
-- Nexthop install, update and delete
+- Nexthop install, update and delete (including labeled nexthops for
+  MPLS imposition, e.g. BGP-LU, L3VPN and SR-MPLS)
+- MPLS LSP install, update and delete (e.g. from LDP)
 - IP address install and uninstall
 - MAC/FDB install and delete
 - VXLAN flood VTEP add and delete

frr/meson.build

@@ -61,6 +61,25 @@ if install_build_flag
   )
 endif
 
+if cmocka_dep.found()
+  # FRR is built as an external subproject and only provides include dirs
+  # (the dplane_grout plugin inherits FRR symbols from the parent process at
+  # runtime). For a standalone test binary we must link libfrr explicitly.
+  frr_prefix = frr_dep.get_variable('prefix')
+  frr_libdir = frr_prefix / 'lib'
+  mpls_frr_test_exe = executable(
+    'mpls_frr_test',
+    files('mpls_frr_test.c', 'rt_grout.c') + grout_header,
+    c_args: frr_c_args + ['-D__GROUT_UNIT_TEST__'],
+    include_directories: api_inc + include_directories('.'),
+    dependencies: [frr_dep, cmocka_dep],
+    link_args: ['-L' + frr_libdir, '-lfrr', '-Wl,-rpath,' + frr_libdir],
+    install: false,
+    override_options: ['b_sanitize=none'],
+  )
+  test('mpls_frr_test', mpls_frr_test_exe, suite: 'unit')
+endif
+
 systemd_dep = dependency('systemd', required: false)
 if systemd_dep.found()
   systemd_system_unit_dir = systemd_dep.get_variable(

frr/mpls_frr_test.c

@@ -0,0 +1,235 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+// Copyright (c) 2025 Matej Muzila
+
+#include "rt_grout.h"
+
+#include <gr_mpls.h>
+#include <gr_nexthop.h>
+
+#include <lib/mpls.h>
+#include <lib/nexthop.h>
+#include <setjmp.h>
+#include <stdarg.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <zebra/zebra_mpls.h>
+
+#include <cmocka.h>
+
+// Forward declarations matching if_map.h so -Wmissing-prototypes is satisfied.
+// These stubs replace if_map.c which is not linked into the test binary.
+uint16_t ifindex_frr_to_grout(ifindex_t);
+uint16_t vrf_frr_to_grout(vrf_id_t);
+
+uint16_t ifindex_frr_to_grout(ifindex_t) {
+	return 0;
+}
+uint16_t vrf_frr_to_grout(vrf_id_t) {
+	return 0;
+}
+
+static void test_lsptype2origin(void **) {
+	assert_int_equal(lsptype2origin(ZEBRA_LSP_STATIC), GR_NH_ORIGIN_ZSTATIC);
+	assert_int_equal(lsptype2origin(ZEBRA_LSP_LDP), GR_NH_ORIGIN_LDP);
+	assert_int_equal(lsptype2origin(ZEBRA_LSP_BGP), GR_NH_ORIGIN_BGP);
+	assert_int_equal(lsptype2origin(ZEBRA_LSP_OSPF_SR), GR_NH_ORIGIN_OSPF);
+	assert_int_equal(lsptype2origin(ZEBRA_LSP_ISIS_SR), GR_NH_ORIGIN_ISIS);
+	assert_int_equal(lsptype2origin(ZEBRA_LSP_SHARP), GR_NH_ORIGIN_SHARP);
+	assert_int_equal(lsptype2origin(ZEBRA_LSP_SRTE), GR_NH_ORIGIN_SRTE);
+	assert_int_equal(lsptype2origin(ZEBRA_LSP_NONE), GR_NH_ORIGIN_ZEBRA);
+	assert_int_equal(lsptype2origin(ZEBRA_LSP_EVPN), GR_NH_ORIGIN_ZEBRA);
+}
+
+static void test_nh_has_mpls_labels_null_label(void **) {
+	struct nexthop nh = {};
+
+	assert_false(nh_has_mpls_labels(&nh));
+}
+
+static void test_nh_has_mpls_labels_zero_count(void **) {
+	struct mpls_label_stack nhl = {.num_labels = 0};
+	struct nexthop nh = {};
+
+	nh.nh_label = &nhl;
+	assert_false(nh_has_mpls_labels(&nh));
+}
+
+static void test_nh_has_mpls_labels_implicit_null(void **) {
+	struct mpls_label_stack *nhl;
+	struct nexthop nh = {};
+
+	nhl = malloc(sizeof(*nhl) + sizeof(mpls_label_t));
+
+	assert_non_null(nhl);
+	nhl->num_labels = 1;
+	nhl->label[0] = MPLS_LABEL_IMPLICIT_NULL;
+	nh.nh_label = nhl;
+	assert_false(nh_has_mpls_labels(&nh));
+	free(nhl);
+}
+
+static void test_nh_has_mpls_labels_real_label(void **) {
+	struct mpls_label_stack *nhl;
+	struct nexthop nh = {};
+
+	nhl = malloc(sizeof(*nhl) + sizeof(mpls_label_t));
+
+	assert_non_null(nhl);
+	nhl->num_labels = 1;
+	nhl->label[0] = 100;
+	nh.nh_label = nhl;
+	assert_true(nh_has_mpls_labels(&nh));
+	free(nhl);
+}
+
+static void test_nh_has_mpls_labels_two_labels(void **) {
+	struct mpls_label_stack *nhl;
+	struct nexthop nh = {};
+
+	nhl = malloc(sizeof(*nhl) + 2 * sizeof(mpls_label_t));
+
+	assert_non_null(nhl);
+	nhl->num_labels = 2;
+	nhl->label[0] = 100;
+	nhl->label[1] = 200;
+	nh.nh_label = nhl;
+	assert_true(nh_has_mpls_labels(&nh));
+	free(nhl);
+}
+
+static void test_fill_mpls_nh_ipv4_one_label(void **) {
+	struct gr_nexthop_info_mpls *mpls;
+	struct mpls_label_stack *nhl;
+	struct gr_nh_add_req *req;
+	struct nexthop nh = {};
+	size_t len;
+
+	len = sizeof(struct gr_nh_add_req) + sizeof(struct gr_nexthop_info_mpls);
+	req = calloc(1, len);
+	mpls = (struct gr_nexthop_info_mpls *)req->nh.info;
+	nhl = malloc(sizeof(*nhl) + sizeof(mpls_label_t));
+
+	assert_non_null(req);
+
+	nh.type = NEXTHOP_TYPE_IPV4_IFINDEX;
+	nh.gate.ipv4.s_addr = htonl(0xAC100102);
+
+	assert_non_null(nhl);
+	nhl->num_labels = 1;
+	nhl->label[0] = 100;
+	nh.nh_label = nhl;
+
+	assert_int_equal(grout_fill_mpls_nh(req, 42, GR_NH_ORIGIN_ZSTATIC, &nh), 0);
+
+	assert_int_equal(mpls->via.af, GR_AF_IP4);
+	assert_int_equal(mpls->n_labels, 1);
+	assert_int_equal(mpls->labels[0], 100);
+	assert_int_equal(mpls->ttl, 0);
+	assert_int_equal(mpls->payload_af, GR_AF_UNSPEC);
+	assert_true(req->exist_ok);
+	assert_int_equal(req->nh.nh_id, 42);
+	assert_int_equal(req->nh.origin, GR_NH_ORIGIN_ZSTATIC);
+	assert_int_equal(req->nh.type, GR_NH_T_MPLS);
+
+	free(nhl);
+	free(req);
+}
+
+static void test_fill_mpls_nh_ipv6_two_labels(void **) {
+	struct gr_nexthop_info_mpls *mpls;
+	struct mpls_label_stack *nhl;
+	struct gr_nh_add_req *req;
+	struct nexthop nh = {};
+	size_t len;
+
+	len = sizeof(struct gr_nh_add_req) + sizeof(struct gr_nexthop_info_mpls);
+	req = calloc(1, len);
+	mpls = (struct gr_nexthop_info_mpls *)req->nh.info;
+	nhl = malloc(sizeof(*nhl) + 2 * sizeof(mpls_label_t));
+
+	assert_non_null(req);
+
+	nh.type = NEXTHOP_TYPE_IPV6_IFINDEX;
+	nh.gate.ipv6.s6_addr[0] = 0xfe;
+	nh.gate.ipv6.s6_addr[1] = 0x80;
+	nh.gate.ipv6.s6_addr[15] = 0x01;
+
+	assert_non_null(nhl);
+	nhl->num_labels = 2;
+	nhl->label[0] = 200;
+	nhl->label[1] = 100;
+	nh.nh_label = nhl;
+
+	assert_int_equal(grout_fill_mpls_nh(req, 43, GR_NH_ORIGIN_BGP, &nh), 0);
+
+	assert_int_equal(mpls->via.af, GR_AF_IP6);
+	assert_int_equal(mpls->n_labels, 2);
+	assert_int_equal(mpls->labels[0], 200);
+	assert_int_equal(mpls->labels[1], 100);
+
+	free(nhl);
+	free(req);
+}
+
+static void test_fill_mpls_nh_too_many_labels(void **) {
+	struct mpls_label_stack *nhl;
+	struct gr_nh_add_req *req;
+	struct nexthop nh = {};
+	size_t len;
+	uint8_t n;
+
+	n = GR_MPLS_MAX_LABELS + 1;
+	len = sizeof(struct gr_nh_add_req) + sizeof(struct gr_nexthop_info_mpls);
+	req = calloc(1, len);
+	nhl = malloc(sizeof(*nhl) + n * sizeof(mpls_label_t));
+
+	assert_non_null(req);
+
+	nh.type = NEXTHOP_TYPE_IPV4;
+	nh.gate.ipv4.s_addr = htonl(0xAC100102);
+
+	assert_non_null(nhl);
+	nhl->num_labels = n;
+	for (uint8_t i = 0; i < n; i++)
+		nhl->label[i] = 100 + i;
+	nh.nh_label = nhl;
+
+	assert_int_equal(grout_fill_mpls_nh(req, 44, GR_NH_ORIGIN_ZSTATIC, &nh), -1);
+
+	free(nhl);
+	free(req);
+}
+
+static void test_fill_mpls_nh_unsupported_type(void **) {
+	struct gr_nh_add_req *req;
+	struct nexthop nh = {};
+	size_t len;
+
+	len = sizeof(struct gr_nh_add_req) + sizeof(struct gr_nexthop_info_mpls);
+	req = calloc(1, len);
+
+	assert_non_null(req);
+
+	nh.type = NEXTHOP_TYPE_BLACKHOLE;
+
+	assert_int_equal(grout_fill_mpls_nh(req, 45, GR_NH_ORIGIN_ZSTATIC, &nh), -1);
+
+	free(req);
+}
+
+int main(void) {
+	const struct CMUnitTest tests[] = {
+		cmocka_unit_test(test_lsptype2origin),
+		cmocka_unit_test(test_nh_has_mpls_labels_null_label),
+		cmocka_unit_test(test_nh_has_mpls_labels_zero_count),
+		cmocka_unit_test(test_nh_has_mpls_labels_implicit_null),
+		cmocka_unit_test(test_nh_has_mpls_labels_real_label),
+		cmocka_unit_test(test_nh_has_mpls_labels_two_labels),
+		cmocka_unit_test(test_fill_mpls_nh_ipv4_one_label),
+		cmocka_unit_test(test_fill_mpls_nh_ipv6_two_labels),
+		cmocka_unit_test(test_fill_mpls_nh_too_many_labels),
+		cmocka_unit_test(test_fill_mpls_nh_unsupported_type),
+	};
+	return cmocka_run_group_tests(tests, NULL, NULL);
+}