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;

modules/infra/api/gr_nexthop.h

@@ -37,6 +37,7 @@ typedef enum : uint8_t {
 	GR_NH_T_BLACKHOLE, // Drop packets silently.
 	GR_NH_T_REJECT, // Drop packets with ICMP error.
 	GR_NH_T_GROUP, // ECMP for multipath routing.
+	GR_NH_T_MPLS, // MPLS label imposition/swap.
 #define GR_NH_T_ALL UINT8_C(0xff) // Match all types in list operations.
 } gr_nh_type_t;
 
@@ -200,6 +201,8 @@ static inline const char *gr_nh_type_name(const gr_nh_type_t type) {
 		return "reject";
 	case GR_NH_T_GROUP:
 		return "group";
+	case GR_NH_T_MPLS:
+		return "MPLS";
 	}
 	return "?";
 }

modules/infra/control/l3_nexthop.c

@@ -46,6 +46,8 @@ const struct nexthop_af_ops *nexthop_af_ops_from_mbuf(const struct rte_mbuf *m)
 		return af_ops[GR_AF_IP4];
 	if (m->packet_type & RTE_PTYPE_L3_IPV6)
 		return af_ops[GR_AF_IP6];
+	if ((m->packet_type & RTE_PTYPE_TUNNEL_MASK) == RTE_PTYPE_TUNNEL_MPLS_IN_GRE)
+		return af_ops[GR_AF_MPLS];
 	return NULL;
 }
 
@@ -79,6 +81,9 @@ static inline void set_nexthop_key(
 			key->ipv6.a[3] = iface_id & 0xff;
 		}
 		break;
+	case GR_AF_MPLS:
+		ABORT("AF_MPLS has no nexthop key with gw");
+		break;
 	case GR_AF_UNSPEC:
 		ABORT("AF_UNSPEC has no nexthop key with gw");
 		break;
@@ -189,6 +194,7 @@ static bool l3_equal(const struct nexthop *a, const struct nexthop *b) {
 	case GR_AF_IP6:
 		return rte_ipv6_addr_eq(&l3_a->ipv6, &l3_b->ipv6);
 	case GR_AF_UNSPEC:
+	case GR_AF_MPLS:
 		return true;
 	}
 	return false;

modules/infra/control/nexthop.c

@@ -236,6 +236,7 @@ bool nexthop_type_valid(gr_nh_type_t type) {
 	case GR_NH_T_BLACKHOLE:
 	case GR_NH_T_REJECT:
 	case GR_NH_T_GROUP:
+	case GR_NH_T_MPLS:
 		return true;
 	}
 	return false;

modules/infra/control/vrf.h

@@ -15,6 +15,7 @@ GR_IFACE_INFO(GR_IFACE_TYPE_VRF, iface_info_vrf, {
 	uint32_t vrf_ifindex;
 	void *fib4;
 	void *fib6;
+	void *fib_mpls;
 });
 
 // Increment VRF reference count.

modules/infra/datapath/checksum.h

@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: BSD-3-Clause
+// Copyright (c) 2025 Matej Muzila
+
+#pragma once
+
+#include <gr_net_types.h>
+
+// RFC 1624 incremental checksum update for a 16-bit field.
+static inline rte_be16_t
+fixup_checksum_16(rte_be16_t old_cksum, rte_be16_t old_field, rte_be16_t new_field) {
+	uint32_t sum;
+
+	sum = ~old_cksum & 0xffff;
+	sum += (~old_field & 0xffff) + new_field;
+	sum = (sum >> 16) + (sum & 0xffff);
+	sum += (sum >> 16);
+
+	return ~sum & 0xffff;
+}
+
+// RFC 1624 incremental checksum update for a 32-bit field.
+static inline rte_be16_t
+fixup_checksum_32(rte_be16_t old_cksum, ip4_addr_t old_addr, ip4_addr_t new_addr) {
+	uint32_t sum;
+
+	sum = ~old_cksum & 0xffff;
+	sum += (~old_addr & 0xffff) + (new_addr & 0xffff);
+	sum += (~old_addr >> 16) + (new_addr >> 16);
+	sum = (sum >> 16) + (sum & 0xffff);
+	sum += (sum >> 16);
+
+	return ~sum & 0xffff;
+}

modules/l2/control/vxlan.c

@@ -197,6 +197,7 @@ static int iface_vxlan_reconfig(
 		cur->template.ipv6.vxlan.vx_vni = vxlan_encode_vni(cur->vni);
 		break;
 	case GR_AF_UNSPEC:
+	case GR_AF_MPLS:
 		break;
 	}
 

modules/meson.build

@@ -5,6 +5,7 @@ subdir('infra')
 subdir('ip')
 subdir('ip6')
 subdir('ipip')
+subdir('mpls')
 subdir('l2')
 subdir('l4')
 subdir('policy')

modules/mpls/api/gr_mpls.h

@@ -0,0 +1,101 @@
+// SPDX-License-Identifier: BSD-3-Clause
+// Copyright (c) 2025 Matej Muzila
+
+#pragma once
+
+#include <gr_api.h>
+#include <gr_net_types.h>
+#include <gr_nexthop.h>
+
+#include <stdint.h>
+
+#define GR_MPLS_MODULE 0xf00e
+
+#define GR_MPLS_MAX_LABELS 16
+
+#define GR_MPLS_MAX_STACK_DEPTH 30
+
+#define GR_MPLS_LABEL_MAX 0xFFFFF
+
+// Reserved MPLS label values (RFC 3032).
+enum gr_mpls_reserved_labels : uint32_t {
+	GR_MPLS_LABEL_IPV4_EXPLICIT_NULL = 0,
+	GR_MPLS_LABEL_ROUTER_ALERT = 1,
+	GR_MPLS_LABEL_IPV6_EXPLICIT_NULL = 2,
+	GR_MPLS_LABEL_IMPLICIT_NULL = 3,
+	GR_MPLS_LABEL_FIRST_UNRESERVED = 16,
+};
+
+struct gr_nexthop_info_mpls {
+	uint8_t n_labels;
+	uint8_t ttl; // 0 = copy from payload.
+	addr_family_t payload_af; // Payload type after pop (GR_AF_UNSPEC = auto-detect).
+	struct l3_addr via;
+	uint32_t labels[GR_MPLS_MAX_LABELS];
+};
+
+// label routes
+enum gr_mpls_requests : uint32_t {
+	GR_MPLS_LABEL_ROUTE_ADD = GR_MSG_TYPE(GR_MPLS_MODULE, 0x0001),
+	GR_MPLS_LABEL_ROUTE_DEL,
+	GR_MPLS_LABEL_ROUTE_GET,
+	GR_MPLS_LABEL_ROUTE_LIST,
+};
+
+// MPLS label route entry.
+struct gr_mpls_label_route {
+	uint16_t vrf_id;
+	uint32_t in_label;
+	uint32_t nh_id;
+	gr_nh_origin_t origin;
+};
+
+// Add a label route to the LFIB.
+struct gr_mpls_label_route_add_req {
+	uint16_t vrf_id;
+	uint32_t in_label; // 0 to GR_MPLS_LABEL_MAX.
+	uint32_t nh_id; // Must reference a GR_NH_T_MPLS nexthop.
+	gr_nh_origin_t origin;
+	uint8_t exist_ok;
+};
+
+GR_REQ(GR_MPLS_LABEL_ROUTE_ADD, struct gr_mpls_label_route_add_req, struct gr_empty);
+
+// Delete a label route from the LFIB.
+struct gr_mpls_label_route_del_req {
+	uint16_t vrf_id;
+	uint32_t in_label;
+	uint8_t missing_ok;
+};
+
+GR_REQ(GR_MPLS_LABEL_ROUTE_DEL, struct gr_mpls_label_route_del_req, struct gr_empty);
+
+// Get a single label route by label value.
+struct gr_mpls_label_route_get_req {
+	uint16_t vrf_id;
+	uint32_t in_label;
+};
+
+GR_REQ(GR_MPLS_LABEL_ROUTE_GET, struct gr_mpls_label_route_get_req, struct gr_mpls_label_route);
+
+// List all label routes in a VRF.
+struct gr_mpls_label_route_list_req {
+	uint16_t vrf_id;
+	uint16_t max_count;
+};
+
+GR_REQ_STREAM(
+	GR_MPLS_LABEL_ROUTE_LIST,
+	struct gr_mpls_label_route_list_req,
+	struct gr_mpls_label_route
+);
+
+// events
+
+enum gr_mpls_events : uint32_t {
+	GR_EVENT_MPLS_ROUTE_ADD = GR_MSG_TYPE(GR_MPLS_MODULE, 0x1001),
+	GR_EVENT_MPLS_ROUTE_DEL,
+};
+
+GR_EVENT(GR_EVENT_MPLS_ROUTE_ADD, struct gr_mpls_label_route);
+GR_EVENT(GR_EVENT_MPLS_ROUTE_DEL, struct gr_mpls_label_route);

modules/mpls/api/meson.build

@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: BSD-3-Clause
+# Copyright (c) 2025 Matej Muzila
+
+api_headers += files('gr_mpls.h')
+api_inc += include_directories('.')