ipv4: add support for icmp echo reply

Signed-off-by: Robin Jarry <[email protected]>

modules/ip4/datapath/arp_input.c

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: BSD-3-Clause
 // Copyright (c) 2024 Robin Jarry
 
-#include "ip4_mbuf.h"
+#include "ip4.h"
 
 #include <br_datapath.h>
 #include <br_graph.h>

modules/ip4/datapath/arp_output_reply.c

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: BSD-3-Clause
 // Copyright (c) 2024 Robin Jarry
 
-#include "ip4_mbuf.h"
+#include "ip4.h"
 
 #include <br_datapath.h>
 #include <br_graph.h>

modules/ip4/datapath/arp_output_request.c

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: BSD-3-Clause
 // Copyright (c) 2024 Robin Jarry
 
-#include "ip4_mbuf.h"
+#include "ip4.h"
 #include "rte_mbuf.h"
 
 #include <br_datapath.h>

modules/ip4/datapath/icmp_input.c

@@ -0,0 +1,94 @@
+// SPDX-License-Identifier: BSD-3-Clause
+// Copyright (c) 2024 Robin Jarry
+
+#include "ip4.h"
+
+#include <br_datapath.h>
+#include <br_graph.h>
+#include <br_ip4_control.h>
+#include <br_log.h>
+#include <br_mbuf.h>
+
+#include <rte_byteorder.h>
+#include <rte_ether.h>
+#include <rte_graph_worker.h>
+#include <rte_icmp.h>
+#include <rte_ip.h>
+
+enum {
+	OUTPUT = 0,
+	INVALID,
+	UNSUPPORTED,
+	EDGE_COUNT,
+};
+
+#define ICMP_MIN_SIZE 8
+
+static uint16_t
+icmp_input_process(struct rte_graph *graph, struct rte_node *node, void **objs, uint16_t nb_objs) {
+	struct ip_local_mbuf_data *ip_data;
+	struct rte_icmp_hdr *icmp;
+	struct rte_mbuf *mbuf;
+	rte_edge_t next;
+	ip4_addr_t ip;
+
+	for (uint16_t i = 0; i < nb_objs; i++) {
+		mbuf = objs[i];
+		icmp = rte_pktmbuf_mtod(mbuf, struct rte_icmp_hdr *);
+		ip_data = ip_local_mbuf_data(mbuf);
+
+		if (ip_data->len < ICMP_MIN_SIZE || (uint16_t)~rte_raw_cksum(icmp, ip_data->len)) {
+			next = INVALID;
+			goto next;
+		}
+		switch (icmp->icmp_type) {
+		case RTE_IP_ICMP_ECHO_REQUEST:
+			if (icmp->icmp_code != 0) {
+				next = INVALID;
+				goto next;
+			}
+			icmp->icmp_type = RTE_IP_ICMP_ECHO_REPLY;
+			ip = ip_data->dst;
+			ip_data->dst = ip_data->src;
+			ip_data->src = ip;
+			break;
+		default:
+			next = UNSUPPORTED;
+			goto next;
+		}
+next:
+		rte_node_enqueue_x1(graph, node, next, mbuf);
+	}
+
+	return nb_objs;
+}
+
+static void icmp_input_register(void) {
+	rte_edge_t edge = br_node_attach_parent("ipv4_input_local", "icmp_input");
+	if (edge == RTE_EDGE_ID_INVALID)
+		ABORT("br_node_attach_parent(classify, icmp_input) failed");
+	ip4_local_add_proto(IPPROTO_ICMP, edge);
+}
+
+static struct rte_node_register icmp_input_node = {
+	.name = "icmp_input",
+
+	.process = icmp_input_process,
+
+	.nb_edges = EDGE_COUNT,
+	.next_nodes = {
+		[OUTPUT] = "icmp_output",
+		[INVALID] = "icmp_input_invalid",
+		[UNSUPPORTED] = "icmp_input_unsupported",
+	},
+};
+
+static struct br_node_info icmp_input_info = {
+	.node = &icmp_input_node,
+	.register_callback = icmp_input_register,
+};
+
+BR_NODE_REGISTER(icmp_input_info);
+
+BR_DROP_REGISTER(icmp_input_invalid);
+BR_DROP_REGISTER(icmp_input_unsupported);

modules/ip4/datapath/icmp_output.c

@@ -0,0 +1,76 @@
+// SPDX-License-Identifier: BSD-3-Clause
+// Copyright (c) 2024 Robin Jarry
+
+#include "ip4.h"
+
+#include <br_datapath.h>
+#include <br_graph.h>
+#include <br_ip4_control.h>
+#include <br_log.h>
+#include <br_mbuf.h>
+
+#include <rte_byteorder.h>
+#include <rte_ether.h>
+#include <rte_graph_worker.h>
+#include <rte_icmp.h>
+#include <rte_ip.h>
+
+#include <netinet/in.h>
+
+enum {
+	OUTPUT = 0,
+	EDGE_COUNT,
+};
+
+#define IPV4_VERSION_IHL 0x45
+
+static uint16_t
+icmp_output_process(struct rte_graph *graph, struct rte_node *node, void **objs, uint16_t nb_objs) {
+	struct ip_local_mbuf_data *local_data;
+	struct rte_icmp_hdr *icmp;
+	struct rte_ipv4_hdr *ip;
+	struct rte_mbuf *mbuf;
+
+	for (uint16_t i = 0; i < nb_objs; i++) {
+		mbuf = objs[i];
+		icmp = rte_pktmbuf_mtod(mbuf, struct rte_icmp_hdr *);
+		local_data = ip_local_mbuf_data(mbuf);
+
+		icmp->icmp_cksum = 0;
+		icmp->icmp_cksum = ~rte_raw_cksum(icmp, local_data->len);
+
+		ip = (struct rte_ipv4_hdr *)rte_pktmbuf_prepend(mbuf, sizeof(*ip));
+
+		memset(ip, 0, sizeof(*ip));
+		ip->version_ihl = IPV4_VERSION_IHL;
+		ip->total_length = rte_cpu_to_be_16(local_data->len + sizeof(*ip));
+		ip->time_to_live = 64;
+		ip->next_proto_id = IPPROTO_ICMP;
+		ip->src_addr = local_data->src;
+		ip->dst_addr = local_data->dst;
+		ip->hdr_checksum = rte_ipv4_cksum(ip);
+
+		ip_output_mbuf_data(mbuf)->nh = NULL;
+
+		rte_node_enqueue_x1(graph, node, OUTPUT, mbuf);
+	}
+
+	return nb_objs;
+}
+
+static struct rte_node_register icmp_output_node = {
+	.name = "icmp_output",
+
+	.process = icmp_output_process,
+
+	.nb_edges = EDGE_COUNT,
+	.next_nodes = {
+		[OUTPUT] = "ipv4_output",
+	},
+};
+
+static struct br_node_info icmp_output_info = {
+	.node = &icmp_output_node,
+};
+
+BR_NODE_REGISTER(icmp_output_info);

modules/ip4/datapath/ip4.h

@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: BSD-3-Clause
+// Copyright (c) 2024 Robin Jarry
+
+#ifndef _IP4_H
+#define _IP4_H
+
+#include <br_mbuf.h>
+#include <br_net_types.h>
+
+#include <rte_graph_worker.h>
+
+#include <stdint.h>
+
+BR_MBUF_PRIV_DATA_TYPE(ip_output_mbuf_data, { struct nexthop *nh; });
+
+BR_MBUF_PRIV_DATA_TYPE(arp_mbuf_data, {
+	struct nexthop *local;
+	struct nexthop *remote;
+});
+
+BR_MBUF_PRIV_DATA_TYPE(ip_local_mbuf_data, {
+	ip4_addr_t src;
+	ip4_addr_t dst;
+	uint16_t len;
+	uint8_t proto;
+});
+
+void ip4_local_add_proto(uint8_t proto, rte_edge_t edge);
+
+#endif

modules/ip4/datapath/ip_input.c

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: BSD-3-Clause
 // Copyright (c) 2024 Robin Jarry
 
-#include "ip4_mbuf.h"
+#include "ip4.h"
 
 #include <br_datapath.h>
 #include <br_graph.h>
@@ -47,11 +47,7 @@ input_process(struct rte_graph *graph, struct rte_node *node, void **objs, uint1
 		// (2) The IP checksum must be correct.
 		if ((mbuf->ol_flags & RTE_MBUF_F_RX_IP_CKSUM_MASK) == RTE_MBUF_F_RX_IP_CKSUM_NONE) {
 			// if this is not checked in H/W, check it.
-			uint16_t actual_cksum, expected_cksum;
-			actual_cksum = ip->hdr_checksum;
-			ip->hdr_checksum = 0;
-			expected_cksum = rte_ipv4_cksum(ip);
-			if (actual_cksum != expected_cksum) {
+			if (rte_ipv4_cksum(ip)) {
 				next = BAD_CHECKSUM;
 				goto next_packet;
 			}
@@ -121,7 +117,6 @@ static struct br_node_info info = {
 
 BR_NODE_REGISTER(info);
 
-BR_DROP_REGISTER(ipv4_input_local);
 BR_DROP_REGISTER(ipv4_input_no_route);
 BR_DROP_REGISTER(ipv4_input_bad_checksum);
 BR_DROP_REGISTER(ipv4_input_bad_length);

modules/ip4/datapath/ip_local.c

@@ -0,0 +1,61 @@
+// SPDX-License-Identifier: BSD-3-Clause
+// Copyright (c) 2024 Robin Jarry
+
+#include "ip4.h"
+
+#include <br_datapath.h>
+#include <br_graph.h>
+
+#include <rte_graph_worker.h>
+#include <rte_ip.h>
+#include <rte_mbuf.h>
+
+#define UNKNOWN_PROTO 0
+static rte_edge_t edges[256] = {UNKNOWN_PROTO};
+
+void ip4_local_add_proto(uint8_t proto, rte_edge_t edge) {
+	edges[proto] = edge;
+	LOG(DEBUG, "ip_input_local: proto=%u -> edge %u", proto, edge);
+}
+
+static uint16_t
+local_process(struct rte_graph *graph, struct rte_node *node, void **objs, uint16_t nb_objs) {
+	struct rte_ipv4_hdr *ip;
+	struct rte_mbuf *mbuf;
+	rte_edge_t next;
+	uint16_t i;
+
+	for (i = 0; i < nb_objs; i++) {
+		mbuf = objs[i];
+		ip = rte_pktmbuf_mtod(mbuf, struct rte_ipv4_hdr *);
+		next = edges[ip->next_proto_id];
+		if (next != UNKNOWN_PROTO) {
+			struct ip_local_mbuf_data *data = ip_local_mbuf_data(mbuf);
+			data->src = ip->src_addr;
+			data->dst = ip->dst_addr;
+			data->len = rte_be_to_cpu_16(ip->total_length) - rte_ipv4_hdr_len(ip);
+			data->proto = ip->next_proto_id;
+			rte_pktmbuf_adj(mbuf, sizeof(*ip));
+		}
+		rte_node_enqueue_x1(graph, node, next, mbuf);
+	}
+
+	return nb_objs;
+}
+
+static struct rte_node_register input_node = {
+	.name = "ipv4_input_local",
+	.process = local_process,
+	.nb_edges = 1,
+	.next_nodes = {
+		[UNKNOWN_PROTO] = "ipv4_input_local_unknown_proto",
+	},
+};
+
+static struct br_node_info info = {
+	.node = &input_node,
+};
+
+BR_NODE_REGISTER(info);
+
+BR_DROP_REGISTER(ipv4_input_local_unknown_proto);

modules/ip4/datapath/ip_output.c

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: BSD-3-Clause
 // Copyright (c) 2024 Robin Jarry
 
-#include "ip4_mbuf.h"
+#include "ip4.h"
 
 #include <br_datapath.h>
 #include <br_graph.h>

modules/ip4/datapath/meson.build

@@ -5,8 +5,11 @@ src += files(
   'arp_input.c',
   'arp_output_reply.c',
   'arp_output_request.c',
+  'icmp_input.c',
+  'icmp_output.c',
   'ip_forward.c',
   'ip_input.c',
+  'ip_local.c',
   'ip_output.c',
 )
 inc += include_directories('.')