mctp-client: add a generic mctp client

meson.build

@@ -65,6 +65,11 @@ executable('mctp-bench',
     sources: ['src/mctp-bench.c'] + util_sources,
 )
 
+executable('mctp-client',
+    sources: ['src/mctp-client.c'] + util_sources,
+    install: true
+)
+
 if libsystemd.found()
     executable('mctpd',
         sources: [

src/mctp-client.c

@@ -0,0 +1,256 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * mctp-client: a raw mctp client for the mctp kernel interface
+ *
+ * Copyright (c) 2025 Nvidia
+ */
+
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <stdbool.h>
+#include <string.h>
+#include <err.h>
+#include <sys/socket.h>
+#include <errno.h>
+#include <limits.h>
+
+#include "mctp.h"
+#include "mctp-util.h"
+
+struct data_t {
+	uint8_t *data;
+	size_t len;
+};
+
+/* Types and values taken from DSP0239 */
+static struct type_lookup_t {
+	const char *name;
+	uint8_t type;
+	const char *description;
+} type_lookup[] = {
+	{
+		.name = "control",
+		.type = 0,
+		.description = "control mctp messages per DSP0236",
+	},
+	{
+		.name = "pldm",
+		.type = 1,
+		.description = "platform level data model per DSP0241",
+	},
+	{
+		.name = "nc-si",
+		.type = 2,
+		.description = "NC-SI traffic over MCTP per DSP0261",
+	},
+	{
+		.name = "ethernet",
+		.type = 3,
+		.description = "Ethernet traffic over MCTP per DSP0261",
+	},
+	{
+		.name = "nvme",
+		.type = 4,
+		.description = "nvme over mctp per DSP0235",
+	},
+	{
+		.name = "spdm",
+		.type = 5,
+		.description = "spdm over mctp per DSP0275",
+	},
+	{
+		.name = "secured",
+		.type = 6,
+		.description = "secured messages using spdm over mctp per DSP0276",
+	},
+	{
+		.name = "pci",
+		.type = 0x7e,
+		.description = "vdm using a pci based vendor id per DSP0236",
+	},
+	{
+		.name = "iana",
+		.type = 0x7f,
+		.description = "vdm using an iana based vendor id per DSP0236",
+	},
+};
+
+static int do_type_lookup(char *type_str) {
+	int ctr;
+
+	for (ctr = 0; ctr < ARRAY_SIZE(type_lookup); ++ctr) {
+		if (!strcmp(type_str, type_lookup[ctr].name))
+			return type_lookup[ctr].type;
+	}
+
+	return -ENOENT;
+};
+
+static int do_send_recv(unsigned int net, mctp_eid_t eid,
+	uint8_t type, struct data_t *data)
+{
+	int sd, rc, recvlen, ctr;
+	struct sockaddr_mctp addr;
+	uint8_t *recv_buffer;
+	socklen_t addrlen;
+
+	sd = socket(AF_MCTP, SOCK_DGRAM, 0);
+	if (sd < 0)
+		err(EXIT_FAILURE, "socket");
+
+
+	memset(&addr, 0, sizeof(addr));
+	addr.smctp_tag = MCTP_TAG_OWNER;
+	addr.smctp_family = AF_MCTP;
+	addr.smctp_network = net;
+	addr.smctp_type = type;
+	addr.smctp_addr.s_addr = eid;
+
+	rc = sendto(sd, data->data, data->len, 0,
+			(struct sockaddr *) &addr, sizeof(addr));
+
+	if (rc != data->len)
+		err(EXIT_FAILURE, "sendto(%zd)", data->len);
+
+	recvlen = recvfrom(sd, NULL, 0, MSG_TRUNC | MSG_PEEK,
+			(struct sockaddr *) &addr, &addrlen);
+
+	if (recvlen < 0)
+		err(EXIT_FAILURE, "receive failed %d", recvlen);
+
+	recv_buffer = malloc(recvlen);
+	if (!recv_buffer)
+		errx(EXIT_FAILURE, "malloc failed for recv");
+
+	rc = recvfrom(sd, recv_buffer, recvlen, MSG_TRUNC,
+			(struct sockaddr *) &addr, &addrlen);
+
+	if (rc < 0)
+		err(EXIT_FAILURE, "receive failed %d", recvlen);
+
+	if (recvlen != rc)
+		errx(EXIT_FAILURE, "invalid bytes received: %d, expected %d", rc, recvlen);
+
+	for (ctr = 0; ctr < rc; ++ctr) {
+		printf("%02X", recv_buffer[ctr]);
+		if (ctr != (rc - 1))
+			printf(" ");
+	}
+
+	printf("\n");
+
+	return 0;
+}
+
+static void print_usage() {
+	int ctr;
+	printf("usage:\n\tmctp-client [net <net>] eid <eid> type <type> data <data>\n");
+	printf("net defaults to MCTP_NET_ANY, data is space delimited hexadecimal. ");
+	printf("data must be the last parameter\n");
+	printf("possible types:\n");
+	for (ctr = 0; ctr < ARRAY_SIZE(type_lookup); ++ctr) {
+		printf("\t%s: %s\n", type_lookup[ctr].name, type_lookup[ctr].description);
+	}
+	printf("return data is always output as space delimited hexadecimal\n");
+}
+
+static struct data_t create_data(char **data_start, size_t count) {
+	unsigned long int tmp;
+	struct data_t data;
+	char *endp;
+	int ctr;
+
+	data.data = malloc(count);
+	if (!data.data)
+		errx(EXIT_FAILURE, "failed to malloc for data");
+
+	if (!count)
+		errx(EXIT_FAILURE, "no data to send");
+
+	data.len = count;
+
+	for (ctr = 0; ctr < count; ++ctr) {
+		tmp = strtoul(data_start[ctr], &endp, 16);
+		if (endp == data_start[ctr])
+			errx(EXIT_FAILURE, "data must be the last parameter");
+		if (tmp == ULONG_MAX)
+			errx(EXIT_FAILURE, "failed to parse: %s", data_start[ctr]);
+		if (tmp > 0xff)
+			errx(EXIT_FAILURE, "data parsed is invalid: %s", data_start[ctr]);
+		data.data[ctr] = tmp;
+	}
+
+	return data;
+}
+
+static int find_data(int argc, char **argv) {
+	int ctr;
+
+	for (ctr = argc - 1; ctr > 0; --ctr) {
+		if (!strcmp(argv[ctr], "data"))
+			return ctr;
+	}
+
+	return -ENOENT;
+}
+
+int main(int argc, char **argv) {
+	bool valid_parse, valid_eid, valid_type;
+	int ctr, data_idx, net = MCTP_NET_ANY;
+	struct data_t send_data;
+	char *tag, *endp, *val;
+	unsigned long int tmp;
+	mctp_eid_t eid;
+	int type;
+
+	data_idx = find_data(argc, argv);
+	if (data_idx < 0) {
+		printf("unable to find data to send\n");
+		print_usage();
+		return EXIT_FAILURE;
+	}
+
+	send_data = create_data(argv + data_idx + 1, argc - data_idx - 1);
+
+	/*
+	 * a little hacky, start by parsing the data since it needs to be last
+	 * then parse the rest of the params
+	 */
+	argc = data_idx;
+	valid_eid = false;
+	valid_type = false;
+
+	for (ctr = 1; ctr < argc; ctr += 2) {
+		tag = argv[ctr];
+		val = argv[ctr + 1];
+		tmp = strtoul(val, &endp, 0);
+		valid_parse = endp != val;
+		if (!strcmp(tag, "eid")) {
+			if (tmp > 0xff)
+				errx(EXIT_FAILURE, "invalid eid: %s", val);
+			eid = tmp;
+			valid_eid = true;
+		} else if (!strcmp(tag, "net")) {
+			if (net > 0xff)
+				errx(EXIT_FAILURE, "invalid net: %s", val);
+			net = tmp;
+		} else if (!strcmp(tag, "type")) {
+			type = do_type_lookup(val);
+			if (type < 0 || type > 0xff)
+				errx(EXIT_FAILURE, "invalid type: %s", val);
+
+			valid_parse = true;
+			valid_type = true;
+		} else
+			errx(EXIT_FAILURE, "invalid tag: %s", tag);
+	}
+
+	if (!valid_parse || !valid_eid || !valid_type) {
+		print_usage();
+		return EXIT_FAILURE;
+	}
+
+	return do_send_recv(net, eid, type, &send_data);
+}