tools/testing/selftests/net/cmsg_sender.c - linux/kernel/git/torvalds/linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 #include <errno.h>
 #include <error.h>
 #include <netdb.h>
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <time.h>
 #include <unistd.h>
 #include <linux/errqueue.h>
 #include <linux/icmp.h>
 #include <linux/icmpv6.h>
 #include <linux/net_tstamp.h>
 #include <linux/types.h>
 #include <linux/udp.h>
 #include <sys/socket.h>

 #include "../kselftest.h"

 enum {
 	ERN_SUCCESS = 0,
 	/* Well defined errors, callers may depend on these */
 	ERN_SEND = 1,
 	/* Informational, can reorder */
 	ERN_HELP,
 	ERN_SEND_SHORT,
 	ERN_SOCK_CREATE,
 	ERN_RESOLVE,
 	ERN_CMSG_WR,
 	ERN_SOCKOPT,
 	ERN_GETTIME,
 	ERN_RECVERR,
 	ERN_CMSG_RD,
 	ERN_CMSG_RCV,
 };

 struct option_cmsg_u32 {
 	bool ena;
 	unsigned int val;
 };

 struct options {
 	bool silent_send;
 	const char *host;
 	const char *service;
 	unsigned int size;
 	struct {
 		unsigned int mark;
 		unsigned int dontfrag;
 		unsigned int tclass;
 		unsigned int hlimit;
 	} sockopt;
 	struct {
 		unsigned int family;
 		unsigned int type;
 		unsigned int proto;
 	} sock;
 	struct option_cmsg_u32 mark;
 	struct {
 		bool ena;
 		unsigned int delay;
 	} txtime;
 	struct {
 		bool ena;
 	} ts;
 	struct {
 		struct option_cmsg_u32 dontfrag;
 		struct option_cmsg_u32 tclass;
 		struct option_cmsg_u32 hlimit;
 		struct option_cmsg_u32 exthdr;
 	} v6;
 } opt = {
 	.size = 13,
 	.sock = {
 		.family	= AF_UNSPEC,
 		.type	= SOCK_DGRAM,
 		.proto	= IPPROTO_UDP,
 	},
 };

 static struct timespec time_start_real;
 static struct timespec time_start_mono;

 static void __attribute__((noreturn)) cs_usage(const char *bin)
 {
 	printf("Usage: %s [opts] <dst host> <dst port / service>\n", bin);
 	printf("Options:\n"
 	       "\t\t-s      Silent send() failures\n"
 	       "\t\t-S      send() size\n"
 	       "\t\t-4/-6   Force IPv4 / IPv6 only\n"
 	       "\t\t-p prot Socket protocol\n"
 	       "\t\t        (u = UDP (default); i = ICMP; r = RAW)\n"
 	       "\n"
 	       "\t\t-m val  Set SO_MARK with given value\n"
 	       "\t\t-M val  Set SO_MARK via setsockopt\n"
 	       "\t\t-d val  Set SO_TXTIME with given delay (usec)\n"
 	       "\t\t-t      Enable time stamp reporting\n"
 	       "\t\t-f val  Set don't fragment via cmsg\n"
 	       "\t\t-F val  Set don't fragment via setsockopt\n"
 	       "\t\t-c val  Set TCLASS via cmsg\n"
 	       "\t\t-C val  Set TCLASS via setsockopt\n"
 	       "\t\t-l val  Set HOPLIMIT via cmsg\n"
 	       "\t\t-L val  Set HOPLIMIT via setsockopt\n"
 	       "\t\t-H type Add an IPv6 header option\n"
 	       "\t\t        (h = HOP; d = DST; r = RTDST)"
 	       "");
 	exit(ERN_HELP);
 }

 static void cs_parse_args(int argc, char *argv[])
 {
 	char o;

 	while ((o = getopt(argc, argv, "46sS:p:m:M:d:tf:F:c:C:l:L:H:")) != -1) {
 		switch (o) {
 		case 's':
 			opt.silent_send = true;
 			break;
 		case 'S':
 			opt.size = atoi(optarg);
 			break;
 		case '4':
 			opt.sock.family = AF_INET;
 			break;
 		case '6':
 			opt.sock.family = AF_INET6;
 			break;
 		case 'p':
 			if (*optarg == 'u' || *optarg == 'U') {
 				opt.sock.proto = IPPROTO_UDP;
 			} else if (*optarg == 'i' || *optarg == 'I') {
 				opt.sock.proto = IPPROTO_ICMP;
 			} else if (*optarg == 'r') {
 				opt.sock.type = SOCK_RAW;
 			} else {
 				printf("Error: unknown protocol: %s\n", optarg);
 				cs_usage(argv[0]);
 			}
 			break;

 		case 'm':
 			opt.mark.ena = true;
 			opt.mark.val = atoi(optarg);
 			break;
 		case 'M':
 			opt.sockopt.mark = atoi(optarg);
 			break;
 		case 'd':
 			opt.txtime.ena = true;
 			opt.txtime.delay = atoi(optarg);
 			break;
 		case 't':
 			opt.ts.ena = true;
 			break;
 		case 'f':
 			opt.v6.dontfrag.ena = true;
 			opt.v6.dontfrag.val = atoi(optarg);
 			break;
 		case 'F':
 			opt.sockopt.dontfrag = atoi(optarg);
 			break;
 		case 'c':
 			opt.v6.tclass.ena = true;
 			opt.v6.tclass.val = atoi(optarg);
 			break;
 		case 'C':
 			opt.sockopt.tclass = atoi(optarg);
 			break;
 		case 'l':
 			opt.v6.hlimit.ena = true;
 			opt.v6.hlimit.val = atoi(optarg);
 			break;
 		case 'L':
 			opt.sockopt.hlimit = atoi(optarg);
 			break;
 		case 'H':
 			opt.v6.exthdr.ena = true;
 			switch (optarg[0]) {
 			case 'h':
 				opt.v6.exthdr.val = IPV6_HOPOPTS;
 				break;
 			case 'd':
 				opt.v6.exthdr.val = IPV6_DSTOPTS;
 				break;
 			case 'r':
 				opt.v6.exthdr.val = IPV6_RTHDRDSTOPTS;
 				break;
 			default:
 				printf("Error: hdr type: %s\n", optarg);
 				break;
 			}
 			break;
 		}
 	}

 	if (optind != argc - 2)
 		cs_usage(argv[0]);

 	opt.host = argv[optind];
 	opt.service = argv[optind + 1];
 }

 static void memrnd(void *s, size_t n)
 {
 	int *dword = s;
 	char *byte;

 	for (; n >= 4; n -= 4)
 		*dword++ = rand();
 	byte = (void *)dword;
 	while (n--)
 		*byte++ = rand();
 }

 static void
 ca_write_cmsg_u32(char *cbuf, size_t cbuf_sz, size_t *cmsg_len,
 		  int level, int optname, struct option_cmsg_u32 *uopt)
 {
 	struct cmsghdr *cmsg;

 	if (!uopt->ena)
 		return;

 	cmsg = (struct cmsghdr *)(cbuf + *cmsg_len);
 	*cmsg_len += CMSG_SPACE(sizeof(__u32));
 	if (cbuf_sz < *cmsg_len)
 		error(ERN_CMSG_WR, EFAULT, "cmsg buffer too small");

 	cmsg->cmsg_level = level;
 	cmsg->cmsg_type = optname;
 	cmsg->cmsg_len = CMSG_LEN(sizeof(__u32));
 	*(__u32 *)CMSG_DATA(cmsg) = uopt->val;
 }

 static void
 cs_write_cmsg(int fd, struct msghdr *msg, char *cbuf, size_t cbuf_sz)
 {
 	struct cmsghdr *cmsg;
 	size_t cmsg_len;

 	msg->msg_control = cbuf;
 	cmsg_len = 0;

 	ca_write_cmsg_u32(cbuf, cbuf_sz, &cmsg_len,
 			  SOL_SOCKET, SO_MARK, &opt.mark);
 	ca_write_cmsg_u32(cbuf, cbuf_sz, &cmsg_len,
 			  SOL_IPV6, IPV6_DONTFRAG, &opt.v6.dontfrag);
 	ca_write_cmsg_u32(cbuf, cbuf_sz, &cmsg_len,
 			  SOL_IPV6, IPV6_TCLASS, &opt.v6.tclass);
 	ca_write_cmsg_u32(cbuf, cbuf_sz, &cmsg_len,
 			  SOL_IPV6, IPV6_HOPLIMIT, &opt.v6.hlimit);

 	if (opt.txtime.ena) {
 		struct sock_txtime so_txtime = {
 			.clockid = CLOCK_MONOTONIC,
 		};
 		__u64 txtime;

 		if (setsockopt(fd, SOL_SOCKET, SO_TXTIME,
 			       &so_txtime, sizeof(so_txtime)))
 			error(ERN_SOCKOPT, errno, "setsockopt TXTIME");

 		txtime = time_start_mono.tv_sec * (1000ULL * 1000 * 1000) +
 			 time_start_mono.tv_nsec +
 			 opt.txtime.delay * 1000;

 		cmsg = (struct cmsghdr *)(cbuf + cmsg_len);
 		cmsg_len += CMSG_SPACE(sizeof(txtime));
 		if (cbuf_sz < cmsg_len)
 			error(ERN_CMSG_WR, EFAULT, "cmsg buffer too small");

 		cmsg->cmsg_level = SOL_SOCKET;
 		cmsg->cmsg_type = SCM_TXTIME;
 		cmsg->cmsg_len = CMSG_LEN(sizeof(txtime));
 		memcpy(CMSG_DATA(cmsg), &txtime, sizeof(txtime));
 	}
 	if (opt.ts.ena) {
 		__u32 val = SOF_TIMESTAMPING_SOFTWARE |
 			    SOF_TIMESTAMPING_OPT_TSONLY;

 		if (setsockopt(fd, SOL_SOCKET, SO_TIMESTAMPING,
 			       &val, sizeof(val)))
 			error(ERN_SOCKOPT, errno, "setsockopt TIMESTAMPING");

 		cmsg = (struct cmsghdr *)(cbuf + cmsg_len);
 		cmsg_len += CMSG_SPACE(sizeof(__u32));
 		if (cbuf_sz < cmsg_len)
 			error(ERN_CMSG_WR, EFAULT, "cmsg buffer too small");

 		cmsg->cmsg_level = SOL_SOCKET;
 		cmsg->cmsg_type = SO_TIMESTAMPING;
 		cmsg->cmsg_len = CMSG_LEN(sizeof(__u32));
 		*(__u32 *)CMSG_DATA(cmsg) = SOF_TIMESTAMPING_TX_SCHED |
 					    SOF_TIMESTAMPING_TX_SOFTWARE;
 	}
 	if (opt.v6.exthdr.ena) {
 		cmsg = (struct cmsghdr *)(cbuf + cmsg_len);
 		cmsg_len += CMSG_SPACE(8);
 		if (cbuf_sz < cmsg_len)
 			error(ERN_CMSG_WR, EFAULT, "cmsg buffer too small");

 		cmsg->cmsg_level = SOL_IPV6;
 		cmsg->cmsg_type = opt.v6.exthdr.val;
 		cmsg->cmsg_len = CMSG_LEN(8);
 		*(__u64 *)CMSG_DATA(cmsg) = 0;
 	}

 	if (cmsg_len)
 		msg->msg_controllen = cmsg_len;
 	else
 		msg->msg_control = NULL;
 }

 static const char *cs_ts_info2str(unsigned int info)
 {
 	static const char *names[] = {
 		[SCM_TSTAMP_SND]	= "SND",
 		[SCM_TSTAMP_SCHED]	= "SCHED",
 		[SCM_TSTAMP_ACK]	= "ACK",
 	};

 	if (info < ARRAY_SIZE(names))
 		return names[info];
 	return "unknown";
 }

 static void
 cs_read_cmsg(int fd, struct msghdr *msg, char *cbuf, size_t cbuf_sz)
 {
 	struct sock_extended_err *see;
 	struct scm_timestamping *ts;
 	struct cmsghdr *cmsg;
 	int i, err;

 	if (!opt.ts.ena)
 		return;
 	msg->msg_control = cbuf;
 	msg->msg_controllen = cbuf_sz;

 	while (true) {
 		ts = NULL;
 		see = NULL;
 		memset(cbuf, 0, cbuf_sz);

 		err = recvmsg(fd, msg, MSG_ERRQUEUE);
 		if (err < 0) {
 			if (errno == EAGAIN)
 				break;
 			error(ERN_RECVERR, errno, "recvmsg ERRQ");
 		}

 		for (cmsg = CMSG_FIRSTHDR(msg); cmsg != NULL;
 		     cmsg = CMSG_NXTHDR(msg, cmsg)) {
 			if (cmsg->cmsg_level == SOL_SOCKET &&
 			    cmsg->cmsg_type == SO_TIMESTAMPING_OLD) {
 				if (cmsg->cmsg_len < sizeof(*ts))
 					error(ERN_CMSG_RD, EINVAL, "TS cmsg");

 				ts = (void *)CMSG_DATA(cmsg);
 			}
 			if ((cmsg->cmsg_level == SOL_IP &&
 			     cmsg->cmsg_type == IP_RECVERR) ||
 			    (cmsg->cmsg_level == SOL_IPV6 &&
 			     cmsg->cmsg_type == IPV6_RECVERR)) {
 				if (cmsg->cmsg_len < sizeof(*see))
 					error(ERN_CMSG_RD, EINVAL, "sock_err cmsg");

 				see = (void *)CMSG_DATA(cmsg);
 			}
 		}

 		if (!ts)
 			error(ERN_CMSG_RCV, ENOENT, "TS cmsg not found");
 		if (!see)
 			error(ERN_CMSG_RCV, ENOENT, "sock_err cmsg not found");

 		for (i = 0; i < 3; i++) {
 			unsigned long long rel_time;

 			if (!ts->ts[i].tv_sec && !ts->ts[i].tv_nsec)
 				continue;

 			rel_time = (ts->ts[i].tv_sec - time_start_real.tv_sec) *
 				(1000ULL * 1000) +
 				(ts->ts[i].tv_nsec - time_start_real.tv_nsec) /
 				1000;
 			printf(" %5s ts%d %lluus\n",
 			       cs_ts_info2str(see->ee_info),
 			       i, rel_time);
 		}
 	}
 }

 static void ca_set_sockopts(int fd)
 {
 	if (opt.sockopt.mark &&
 	    setsockopt(fd, SOL_SOCKET, SO_MARK,
 		       &opt.sockopt.mark, sizeof(opt.sockopt.mark)))
 		error(ERN_SOCKOPT, errno, "setsockopt SO_MARK");
 	if (opt.sockopt.dontfrag &&
 	    setsockopt(fd, SOL_IPV6, IPV6_DONTFRAG,
 		       &opt.sockopt.dontfrag, sizeof(opt.sockopt.dontfrag)))
 		error(ERN_SOCKOPT, errno, "setsockopt IPV6_DONTFRAG");
 	if (opt.sockopt.tclass &&
 	    setsockopt(fd, SOL_IPV6, IPV6_TCLASS,
 		       &opt.sockopt.tclass, sizeof(opt.sockopt.tclass)))
 		error(ERN_SOCKOPT, errno, "setsockopt IPV6_TCLASS");
 	if (opt.sockopt.hlimit &&
 	    setsockopt(fd, SOL_IPV6, IPV6_UNICAST_HOPS,
 		       &opt.sockopt.hlimit, sizeof(opt.sockopt.hlimit)))
 		error(ERN_SOCKOPT, errno, "setsockopt IPV6_HOPLIMIT");
 }

 int main(int argc, char *argv[])
 {
 	struct addrinfo hints, *ai;
 	struct iovec iov[1];
 	struct msghdr msg;
 	char cbuf[1024];
 	char *buf;
 	int err;
 	int fd;

 	cs_parse_args(argc, argv);

 	buf = malloc(opt.size);
 	memrnd(buf, opt.size);

 	memset(&hints, 0, sizeof(hints));
 	hints.ai_family = opt.sock.family;

 	ai = NULL;
 	err = getaddrinfo(opt.host, opt.service, &hints, &ai);
 	if (err) {
 		fprintf(stderr, "Can't resolve address [%s]:%s\n",
 			opt.host, opt.service);
 		return ERN_SOCK_CREATE;
 	}

 	if (ai->ai_family == AF_INET6 && opt.sock.proto == IPPROTO_ICMP)
 		opt.sock.proto = IPPROTO_ICMPV6;

 	fd = socket(ai->ai_family, opt.sock.type, opt.sock.proto);
 	if (fd < 0) {
 		fprintf(stderr, "Can't open socket: %s\n", strerror(errno));
 		freeaddrinfo(ai);
 		return ERN_RESOLVE;
 	}

 	if (opt.sock.proto == IPPROTO_ICMP) {
 		buf[0] = ICMP_ECHO;
 		buf[1] = 0;
 	} else if (opt.sock.proto == IPPROTO_ICMPV6) {
 		buf[0] = ICMPV6_ECHO_REQUEST;
 		buf[1] = 0;
 	} else if (opt.sock.type == SOCK_RAW) {
 		struct udphdr hdr = { 1, 2, htons(opt.size), 0 };
 		struct sockaddr_in6 *sin6 = (void *)ai->ai_addr;;

 		memcpy(buf, &hdr, sizeof(hdr));
 		sin6->sin6_port = htons(opt.sock.proto);
 	}

 	ca_set_sockopts(fd);

 	if (clock_gettime(CLOCK_REALTIME, &time_start_real))
 		error(ERN_GETTIME, errno, "gettime REALTIME");
 	if (clock_gettime(CLOCK_MONOTONIC, &time_start_mono))
 		error(ERN_GETTIME, errno, "gettime MONOTONIC");

 	iov[0].iov_base = buf;
 	iov[0].iov_len = opt.size;

 	memset(&msg, 0, sizeof(msg));
 	msg.msg_name = ai->ai_addr;
 	msg.msg_namelen = ai->ai_addrlen;
 	msg.msg_iov = iov;
 	msg.msg_iovlen = 1;

 	cs_write_cmsg(fd, &msg, cbuf, sizeof(cbuf));

 	err = sendmsg(fd, &msg, 0);
 	if (err < 0) {
 		if (!opt.silent_send)
 			fprintf(stderr, "send failed: %s\n", strerror(errno));
 		err = ERN_SEND;
 		goto err_out;
 	} else if (err != (int)opt.size) {
 		fprintf(stderr, "short send\n");
 		err = ERN_SEND_SHORT;
 		goto err_out;
 	} else {
 		err = ERN_SUCCESS;
 	}

 	/* Make sure all timestamps have time to loop back */
 	usleep(opt.txtime.delay);

 	cs_read_cmsg(fd, &msg, cbuf, sizeof(cbuf));

 err_out:
 	close(fd);
 	freeaddrinfo(ai);
 	return err;
 }
	// SPDX-License-Identifier: GPL-2.0-or-later
	#include <errno.h>
	#include <error.h>
	#include <netdb.h>
	#include <stdbool.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include <time.h>
	#include <unistd.h>
	#include <linux/errqueue.h>
	#include <linux/icmp.h>
	#include <linux/icmpv6.h>
	#include <linux/net_tstamp.h>
	#include <linux/types.h>
	#include <linux/udp.h>
	#include <sys/socket.h>

	#include "../kselftest.h"

	enum {
	ERN_SUCCESS = 0,
	/* Well defined errors, callers may depend on these */
	ERN_SEND = 1,
	/* Informational, can reorder */
	ERN_HELP,
	ERN_SEND_SHORT,
	ERN_SOCK_CREATE,
	ERN_RESOLVE,
	ERN_CMSG_WR,
	ERN_SOCKOPT,
	ERN_GETTIME,
	ERN_RECVERR,
	ERN_CMSG_RD,
	ERN_CMSG_RCV,
	};

	struct option_cmsg_u32 {
	bool ena;
	unsigned int val;
	};

	struct options {
	bool silent_send;
	const char *host;
	const char *service;
	unsigned int size;
	struct {
	unsigned int mark;
	unsigned int dontfrag;
	unsigned int tclass;
	unsigned int hlimit;
	} sockopt;
	struct {
	unsigned int family;
	unsigned int type;
	unsigned int proto;
	} sock;
	struct option_cmsg_u32 mark;
	struct {
	bool ena;
	unsigned int delay;
	} txtime;
	struct {
	bool ena;
	} ts;
	struct {
	struct option_cmsg_u32 dontfrag;
	struct option_cmsg_u32 tclass;
	struct option_cmsg_u32 hlimit;
	struct option_cmsg_u32 exthdr;
	} v6;
	} opt = {
	.size = 13,
	.sock = {
	.family = AF_UNSPEC,
	.type = SOCK_DGRAM,
	.proto = IPPROTO_UDP,
	},
	};

	static struct timespec time_start_real;
	static struct timespec time_start_mono;

	static void __attribute__((noreturn)) cs_usage(const char *bin)
	{
	printf("Usage: %s [opts] <dst host> <dst port / service>\n", bin);
	printf("Options:\n"
	"\t\t-s Silent send() failures\n"
	"\t\t-S send() size\n"
	"\t\t-4/-6 Force IPv4 / IPv6 only\n"
	"\t\t-p prot Socket protocol\n"
	"\t\t (u = UDP (default); i = ICMP; r = RAW)\n"
	"\n"
	"\t\t-m val Set SO_MARK with given value\n"
	"\t\t-M val Set SO_MARK via setsockopt\n"
	"\t\t-d val Set SO_TXTIME with given delay (usec)\n"
	"\t\t-t Enable time stamp reporting\n"
	"\t\t-f val Set don't fragment via cmsg\n"
	"\t\t-F val Set don't fragment via setsockopt\n"
	"\t\t-c val Set TCLASS via cmsg\n"
	"\t\t-C val Set TCLASS via setsockopt\n"
	"\t\t-l val Set HOPLIMIT via cmsg\n"
	"\t\t-L val Set HOPLIMIT via setsockopt\n"
	"\t\t-H type Add an IPv6 header option\n"
	"\t\t (h = HOP; d = DST; r = RTDST)"
	"");
	exit(ERN_HELP);
	}

	static void cs_parse_args(int argc, char *argv[])
	{
	char o;

	while ((o = getopt(argc, argv, "46sS:p:m:M:d:tf:F:c:C:l:L:H:")) != -1) {
	switch (o) {
	case 's':
	opt.silent_send = true;
	break;
	case 'S':
	opt.size = atoi(optarg);
	break;
	case '4':
	opt.sock.family = AF_INET;
	break;
	case '6':
	opt.sock.family = AF_INET6;
	break;
	case 'p':
	if (optarg == 'u' \|\| optarg == 'U') {
	opt.sock.proto = IPPROTO_UDP;
	} else if (optarg == 'i' \|\| optarg == 'I') {
	opt.sock.proto = IPPROTO_ICMP;
	} else if (*optarg == 'r') {
	opt.sock.type = SOCK_RAW;
	} else {
	printf("Error: unknown protocol: %s\n", optarg);
	cs_usage(argv[0]);
	}
	break;

	case 'm':
	opt.mark.ena = true;
	opt.mark.val = atoi(optarg);
	break;
	case 'M':
	opt.sockopt.mark = atoi(optarg);
	break;
	case 'd':
	opt.txtime.ena = true;
	opt.txtime.delay = atoi(optarg);
	break;
	case 't':
	opt.ts.ena = true;
	break;
	case 'f':
	opt.v6.dontfrag.ena = true;
	opt.v6.dontfrag.val = atoi(optarg);
	break;
	case 'F':
	opt.sockopt.dontfrag = atoi(optarg);
	break;
	case 'c':
	opt.v6.tclass.ena = true;
	opt.v6.tclass.val = atoi(optarg);
	break;
	case 'C':
	opt.sockopt.tclass = atoi(optarg);
	break;
	case 'l':
	opt.v6.hlimit.ena = true;
	opt.v6.hlimit.val = atoi(optarg);
	break;
	case 'L':
	opt.sockopt.hlimit = atoi(optarg);
	break;
	case 'H':
	opt.v6.exthdr.ena = true;
	switch (optarg[0]) {
	case 'h':
	opt.v6.exthdr.val = IPV6_HOPOPTS;
	break;
	case 'd':
	opt.v6.exthdr.val = IPV6_DSTOPTS;
	break;
	case 'r':
	opt.v6.exthdr.val = IPV6_RTHDRDSTOPTS;
	break;
	default:
	printf("Error: hdr type: %s\n", optarg);
	break;
	}
	break;
	}
	}

	if (optind != argc - 2)
	cs_usage(argv[0]);

	opt.host = argv[optind];
	opt.service = argv[optind + 1];
	}

	static void memrnd(void *s, size_t n)
	{
	int *dword = s;
	char *byte;

	for (; n >= 4; n -= 4)
	*dword++ = rand();
	byte = (void *)dword;
	while (n--)
	*byte++ = rand();
	}

	static void
	ca_write_cmsg_u32(char cbuf, size_t cbuf_sz, size_t cmsg_len,
	int level, int optname, struct option_cmsg_u32 *uopt)
	{
	struct cmsghdr *cmsg;

	if (!uopt->ena)
	return;

	cmsg = (struct cmsghdr )(cbuf + cmsg_len);
	*cmsg_len += CMSG_SPACE(sizeof(__u32));
	if (cbuf_sz < *cmsg_len)
	error(ERN_CMSG_WR, EFAULT, "cmsg buffer too small");

	cmsg->cmsg_level = level;
	cmsg->cmsg_type = optname;
	cmsg->cmsg_len = CMSG_LEN(sizeof(__u32));
	(__u32 )CMSG_DATA(cmsg) = uopt->val;
	}

	static void
	cs_write_cmsg(int fd, struct msghdr msg, char cbuf, size_t cbuf_sz)
	{
	struct cmsghdr *cmsg;
	size_t cmsg_len;

	msg->msg_control = cbuf;
	cmsg_len = 0;

	ca_write_cmsg_u32(cbuf, cbuf_sz, &cmsg_len,
	SOL_SOCKET, SO_MARK, &opt.mark);
	ca_write_cmsg_u32(cbuf, cbuf_sz, &cmsg_len,
	SOL_IPV6, IPV6_DONTFRAG, &opt.v6.dontfrag);
	ca_write_cmsg_u32(cbuf, cbuf_sz, &cmsg_len,
	SOL_IPV6, IPV6_TCLASS, &opt.v6.tclass);
	ca_write_cmsg_u32(cbuf, cbuf_sz, &cmsg_len,
	SOL_IPV6, IPV6_HOPLIMIT, &opt.v6.hlimit);

	if (opt.txtime.ena) {
	struct sock_txtime so_txtime = {
	.clockid = CLOCK_MONOTONIC,
	};
	__u64 txtime;

	if (setsockopt(fd, SOL_SOCKET, SO_TXTIME,
	&so_txtime, sizeof(so_txtime)))
	error(ERN_SOCKOPT, errno, "setsockopt TXTIME");

	txtime = time_start_mono.tv_sec * (1000ULL * 1000 * 1000) +
	time_start_mono.tv_nsec +
	opt.txtime.delay * 1000;

	cmsg = (struct cmsghdr *)(cbuf + cmsg_len);
	cmsg_len += CMSG_SPACE(sizeof(txtime));
	if (cbuf_sz < cmsg_len)
	error(ERN_CMSG_WR, EFAULT, "cmsg buffer too small");

	cmsg->cmsg_level = SOL_SOCKET;
	cmsg->cmsg_type = SCM_TXTIME;
	cmsg->cmsg_len = CMSG_LEN(sizeof(txtime));
	memcpy(CMSG_DATA(cmsg), &txtime, sizeof(txtime));
	}
	if (opt.ts.ena) {
	__u32 val = SOF_TIMESTAMPING_SOFTWARE \|
	SOF_TIMESTAMPING_OPT_TSONLY;

	if (setsockopt(fd, SOL_SOCKET, SO_TIMESTAMPING,
	&val, sizeof(val)))
	error(ERN_SOCKOPT, errno, "setsockopt TIMESTAMPING");

	cmsg = (struct cmsghdr *)(cbuf + cmsg_len);
	cmsg_len += CMSG_SPACE(sizeof(__u32));
	if (cbuf_sz < cmsg_len)
	error(ERN_CMSG_WR, EFAULT, "cmsg buffer too small");

	cmsg->cmsg_level = SOL_SOCKET;
	cmsg->cmsg_type = SO_TIMESTAMPING;
	cmsg->cmsg_len = CMSG_LEN(sizeof(__u32));
	(__u32 )CMSG_DATA(cmsg) = SOF_TIMESTAMPING_TX_SCHED \|
	SOF_TIMESTAMPING_TX_SOFTWARE;
	}
	if (opt.v6.exthdr.ena) {
	cmsg = (struct cmsghdr *)(cbuf + cmsg_len);
	cmsg_len += CMSG_SPACE(8);
	if (cbuf_sz < cmsg_len)
	error(ERN_CMSG_WR, EFAULT, "cmsg buffer too small");

	cmsg->cmsg_level = SOL_IPV6;
	cmsg->cmsg_type = opt.v6.exthdr.val;
	cmsg->cmsg_len = CMSG_LEN(8);
	(__u64 )CMSG_DATA(cmsg) = 0;
	}

	if (cmsg_len)
	msg->msg_controllen = cmsg_len;
	else
	msg->msg_control = NULL;
	}

	static const char *cs_ts_info2str(unsigned int info)
	{
	static const char *names[] = {
	[SCM_TSTAMP_SND] = "SND",
	[SCM_TSTAMP_SCHED] = "SCHED",
	[SCM_TSTAMP_ACK] = "ACK",
	};

	if (info < ARRAY_SIZE(names))
	return names[info];
	return "unknown";
	}

	static void
	cs_read_cmsg(int fd, struct msghdr msg, char cbuf, size_t cbuf_sz)
	{
	struct sock_extended_err *see;
	struct scm_timestamping *ts;
	struct cmsghdr *cmsg;
	int i, err;

	if (!opt.ts.ena)
	return;
	msg->msg_control = cbuf;
	msg->msg_controllen = cbuf_sz;

	while (true) {
	ts = NULL;
	see = NULL;
	memset(cbuf, 0, cbuf_sz);

	err = recvmsg(fd, msg, MSG_ERRQUEUE);
	if (err < 0) {
	if (errno == EAGAIN)
	break;
	error(ERN_RECVERR, errno, "recvmsg ERRQ");
	}

	for (cmsg = CMSG_FIRSTHDR(msg); cmsg != NULL;
	cmsg = CMSG_NXTHDR(msg, cmsg)) {
	if (cmsg->cmsg_level == SOL_SOCKET &&
	cmsg->cmsg_type == SO_TIMESTAMPING_OLD) {
	if (cmsg->cmsg_len < sizeof(*ts))
	error(ERN_CMSG_RD, EINVAL, "TS cmsg");

	ts = (void *)CMSG_DATA(cmsg);
	}
	if ((cmsg->cmsg_level == SOL_IP &&
	cmsg->cmsg_type == IP_RECVERR) \|\|
	(cmsg->cmsg_level == SOL_IPV6 &&
	cmsg->cmsg_type == IPV6_RECVERR)) {
	if (cmsg->cmsg_len < sizeof(*see))
	error(ERN_CMSG_RD, EINVAL, "sock_err cmsg");

	see = (void *)CMSG_DATA(cmsg);
	}
	}

	if (!ts)
	error(ERN_CMSG_RCV, ENOENT, "TS cmsg not found");
	if (!see)
	error(ERN_CMSG_RCV, ENOENT, "sock_err cmsg not found");

	for (i = 0; i < 3; i++) {
	unsigned long long rel_time;

	if (!ts->ts[i].tv_sec && !ts->ts[i].tv_nsec)
	continue;

	rel_time = (ts->ts[i].tv_sec - time_start_real.tv_sec) *
	(1000ULL * 1000) +
	(ts->ts[i].tv_nsec - time_start_real.tv_nsec) /
	1000;
	printf(" %5s ts%d %lluus\n",
	cs_ts_info2str(see->ee_info),
	i, rel_time);
	}
	}
	}

	static void ca_set_sockopts(int fd)
	{
	if (opt.sockopt.mark &&
	setsockopt(fd, SOL_SOCKET, SO_MARK,
	&opt.sockopt.mark, sizeof(opt.sockopt.mark)))
	error(ERN_SOCKOPT, errno, "setsockopt SO_MARK");
	if (opt.sockopt.dontfrag &&
	setsockopt(fd, SOL_IPV6, IPV6_DONTFRAG,
	&opt.sockopt.dontfrag, sizeof(opt.sockopt.dontfrag)))
	error(ERN_SOCKOPT, errno, "setsockopt IPV6_DONTFRAG");
	if (opt.sockopt.tclass &&
	setsockopt(fd, SOL_IPV6, IPV6_TCLASS,
	&opt.sockopt.tclass, sizeof(opt.sockopt.tclass)))
	error(ERN_SOCKOPT, errno, "setsockopt IPV6_TCLASS");
	if (opt.sockopt.hlimit &&
	setsockopt(fd, SOL_IPV6, IPV6_UNICAST_HOPS,
	&opt.sockopt.hlimit, sizeof(opt.sockopt.hlimit)))
	error(ERN_SOCKOPT, errno, "setsockopt IPV6_HOPLIMIT");
	}

	int main(int argc, char *argv[])
	{
	struct addrinfo hints, *ai;
	struct iovec iov[1];
	struct msghdr msg;
	char cbuf[1024];
	char *buf;
	int err;
	int fd;

	cs_parse_args(argc, argv);

	buf = malloc(opt.size);
	memrnd(buf, opt.size);

	memset(&hints, 0, sizeof(hints));
	hints.ai_family = opt.sock.family;

	ai = NULL;
	err = getaddrinfo(opt.host, opt.service, &hints, &ai);
	if (err) {
	fprintf(stderr, "Can't resolve address [%s]:%s\n",
	opt.host, opt.service);
	return ERN_SOCK_CREATE;
	}

	if (ai->ai_family == AF_INET6 && opt.sock.proto == IPPROTO_ICMP)
	opt.sock.proto = IPPROTO_ICMPV6;

	fd = socket(ai->ai_family, opt.sock.type, opt.sock.proto);
	if (fd < 0) {
	fprintf(stderr, "Can't open socket: %s\n", strerror(errno));
	freeaddrinfo(ai);
	return ERN_RESOLVE;
	}

	if (opt.sock.proto == IPPROTO_ICMP) {
	buf[0] = ICMP_ECHO;
	buf[1] = 0;
	} else if (opt.sock.proto == IPPROTO_ICMPV6) {
	buf[0] = ICMPV6_ECHO_REQUEST;
	buf[1] = 0;
	} else if (opt.sock.type == SOCK_RAW) {
	struct udphdr hdr = { 1, 2, htons(opt.size), 0 };
	struct sockaddr_in6 sin6 = (void )ai->ai_addr;;

	memcpy(buf, &hdr, sizeof(hdr));
	sin6->sin6_port = htons(opt.sock.proto);
	}

	ca_set_sockopts(fd);

	if (clock_gettime(CLOCK_REALTIME, &time_start_real))
	error(ERN_GETTIME, errno, "gettime REALTIME");
	if (clock_gettime(CLOCK_MONOTONIC, &time_start_mono))
	error(ERN_GETTIME, errno, "gettime MONOTONIC");

	iov[0].iov_base = buf;
	iov[0].iov_len = opt.size;

	memset(&msg, 0, sizeof(msg));
	msg.msg_name = ai->ai_addr;
	msg.msg_namelen = ai->ai_addrlen;
	msg.msg_iov = iov;
	msg.msg_iovlen = 1;

	cs_write_cmsg(fd, &msg, cbuf, sizeof(cbuf));

	err = sendmsg(fd, &msg, 0);
	if (err < 0) {
	if (!opt.silent_send)
	fprintf(stderr, "send failed: %s\n", strerror(errno));
	err = ERN_SEND;
	goto err_out;
	} else if (err != (int)opt.size) {
	fprintf(stderr, "short send\n");
	err = ERN_SEND_SHORT;
	goto err_out;
	} else {
	err = ERN_SUCCESS;
	}

	/* Make sure all timestamps have time to loop back */
	usleep(opt.txtime.delay);

	cs_read_cmsg(fd, &msg, cbuf, sizeof(cbuf));

	err_out:
	close(fd);
	freeaddrinfo(ai);
	return err;
	}