root/tools/testing/selftests/net/txtimestamp.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright 2014 Google Inc.
 * Author: willemb@google.com (Willem de Bruijn)
 *
 * Test software tx timestamping, including
 *
 * - SCHED, SND and ACK timestamps
 * - RAW, UDP and TCP
 * - IPv4 and IPv6
 * - various packet sizes (to test GSO and TSO)
 *
 * Consult the command line arguments for help on running
 * the various testcases.
 *
 * This test requires a dummy TCP server.
 * A simple `nc6 [-u] -l -p $DESTPORT` will do
 */

#define _GNU_SOURCE

#include <arpa/inet.h>
#include <asm/types.h>
#include <error.h>
#include <errno.h>
#include <inttypes.h>
#include <linux/errqueue.h>
#include <linux/if_ether.h>
#include <linux/if_packet.h>
#include <linux/ipv6.h>
#include <linux/net_tstamp.h>
#include <netdb.h>
#include <net/if.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/udp.h>
#include <netinet/tcp.h>
#include <poll.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/epoll.h>
#include <sys/ioctl.h>
#include <sys/select.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/types.h>
#include <time.h>
#include <unistd.h>

#define NSEC_PER_USEC   1000L
#define USEC_PER_SEC    1000000L
#define NSEC_PER_SEC    1000000000LL

/* command line parameters */
static int cfg_proto = SOCK_STREAM;
static int cfg_ipproto = IPPROTO_TCP;
static int cfg_num_pkts = 4;
static int do_ipv4 = 1;
static int do_ipv6 = 1;
static int cfg_payload_len = 10;
static int cfg_poll_timeout = 100;
static int cfg_delay_snd;
static int cfg_delay_ack;
static int cfg_delay_tolerance_usec = 500;
static bool cfg_show_payload;
static bool cfg_do_pktinfo;
static bool cfg_busy_poll;
static int cfg_sleep_usec = 50 * 1000;
static bool cfg_loop_nodata;
static bool cfg_use_cmsg;
static bool cfg_use_pf_packet;
static bool cfg_use_epoll;
static bool cfg_epollet;
static bool cfg_do_listen;
static uint16_t dest_port = 9000;
static bool cfg_print_nsec;
static uint32_t ts_opt_id;
static bool cfg_use_cmsg_opt_id;

static struct sockaddr_in daddr;
static struct sockaddr_in6 daddr6;
static struct timespec ts_usr;

static int saved_tskey = -1;
static int saved_tskey_type = -1;

struct timing_event {
        int64_t min;
        int64_t max;
        int64_t total;
        int count;
};

static struct timing_event usr_enq;
static struct timing_event usr_snd;
static struct timing_event usr_ack;

static bool test_failed;

static int64_t timespec_to_ns64(struct timespec *ts)
{
        return ts->tv_sec * NSEC_PER_SEC + ts->tv_nsec;
}

static int64_t timespec_to_us64(struct timespec *ts)
{
        return ts->tv_sec * USEC_PER_SEC + ts->tv_nsec / NSEC_PER_USEC;
}

static void init_timing_event(struct timing_event *te)
{
        te->min = INT64_MAX;
        te->max = 0;
        te->total = 0;
        te->count = 0;
}

static void add_timing_event(struct timing_event *te,
                struct timespec *t_start, struct timespec *t_end)
{
        int64_t ts_delta = timespec_to_ns64(t_end) - timespec_to_ns64(t_start);

        te->count++;
        if (ts_delta < te->min)
                te->min = ts_delta;
        if (ts_delta > te->max)
                te->max = ts_delta;
        te->total += ts_delta;
}

static void validate_key(int tskey, int tstype)
{
        int stepsize;

        /* compare key for each subsequent request
         * must only test for one type, the first one requested
         */
        if (saved_tskey == -1 || cfg_use_cmsg_opt_id)
                saved_tskey_type = tstype;
        else if (saved_tskey_type != tstype)
                return;

        stepsize = cfg_proto == SOCK_STREAM ? cfg_payload_len : 1;
        stepsize = cfg_use_cmsg_opt_id ? 0 : stepsize;
        if (tskey != saved_tskey + stepsize) {
                fprintf(stderr, "ERROR: key %d, expected %d\n",
                                tskey, saved_tskey + stepsize);
                test_failed = true;
        }

        saved_tskey = tskey;
}

static void validate_timestamp(struct timespec *cur, int min_delay)
{
        int64_t cur64, start64;
        int max_delay;

        cur64 = timespec_to_us64(cur);
        start64 = timespec_to_us64(&ts_usr);
        max_delay = min_delay + cfg_delay_tolerance_usec;

        if (cur64 < start64 + min_delay || cur64 > start64 + max_delay) {
                fprintf(stderr, "ERROR: %" PRId64 " us expected between %d and %d\n",
                                cur64 - start64, min_delay, max_delay);
                if (!getenv("KSFT_MACHINE_SLOW"))
                        test_failed = true;
        }
}

static void __print_ts_delta_formatted(int64_t ts_delta)
{
        if (cfg_print_nsec)
                fprintf(stderr, "%" PRId64 " ns", ts_delta);
        else
                fprintf(stderr, "%" PRId64 " us", ts_delta / NSEC_PER_USEC);
}

static void __print_timestamp(const char *name, struct timespec *cur,
                              uint32_t key, int payload_len)
{
        int64_t ts_delta;

        if (!(cur->tv_sec | cur->tv_nsec))
                return;

        if (cfg_print_nsec)
                fprintf(stderr, "  %s: %lu s %lu ns (seq=%u, len=%u)",
                                name, cur->tv_sec, cur->tv_nsec,
                                key, payload_len);
        else
                fprintf(stderr, "  %s: %lu s %lu us (seq=%u, len=%u)",
                                name, cur->tv_sec, cur->tv_nsec / NSEC_PER_USEC,
                                key, payload_len);

        if (cur != &ts_usr) {
                ts_delta = timespec_to_ns64(cur) - timespec_to_ns64(&ts_usr);
                fprintf(stderr, "  (USR +");
                __print_ts_delta_formatted(ts_delta);
                fprintf(stderr, ")");
        }

        fprintf(stderr, "\n");
}

static void record_timestamp_usr(void)
{
        if (clock_gettime(CLOCK_REALTIME, &ts_usr))
                error(1, errno, "clock_gettime");
}

static void print_timestamp(struct scm_timestamping *tss, int tstype,
                            int tskey, int payload_len)
{
        const char *tsname = NULL;

        validate_key(tskey, tstype);

        switch (tstype) {
        case SCM_TSTAMP_SCHED:
                tsname = "  ENQ";
                validate_timestamp(&tss->ts[0], 0);
                add_timing_event(&usr_enq, &ts_usr, &tss->ts[0]);
                break;
        case SCM_TSTAMP_SND:
                tsname = "  SND";
                validate_timestamp(&tss->ts[0], cfg_delay_snd);
                add_timing_event(&usr_snd, &ts_usr, &tss->ts[0]);
                break;
        case SCM_TSTAMP_ACK:
                tsname = "  ACK";
                validate_timestamp(&tss->ts[0], cfg_delay_ack);
                add_timing_event(&usr_ack, &ts_usr, &tss->ts[0]);
                break;
        default:
                error(1, 0, "unknown timestamp type: %u",
                tstype);
        }
        __print_timestamp(tsname, &tss->ts[0], tskey, payload_len);
}

static void print_timing_event(char *name, struct timing_event *te)
{
        if (!te->count)
                return;

        fprintf(stderr, "    %s: count=%d", name, te->count);
        fprintf(stderr, ", avg=");
        __print_ts_delta_formatted((int64_t)(te->total / te->count));
        fprintf(stderr, ", min=");
        __print_ts_delta_formatted(te->min);
        fprintf(stderr, ", max=");
        __print_ts_delta_formatted(te->max);
        fprintf(stderr, "\n");
}

/* TODO: convert to check_and_print payload once API is stable */
static void print_payload(char *data, int len)
{
        int i;

        if (!len)
                return;

        if (len > 70)
                len = 70;

        fprintf(stderr, "payload: ");
        for (i = 0; i < len; i++)
                fprintf(stderr, "%02hhx ", data[i]);
        fprintf(stderr, "\n");
}

static void print_pktinfo(int family, int ifindex, void *saddr, void *daddr)
{
        char sa[INET6_ADDRSTRLEN], da[INET6_ADDRSTRLEN];

        fprintf(stderr, "         pktinfo: ifindex=%u src=%s dst=%s\n",
                ifindex,
                saddr ? inet_ntop(family, saddr, sa, sizeof(sa)) : "unknown",
                daddr ? inet_ntop(family, daddr, da, sizeof(da)) : "unknown");
}

static void __epoll(int epfd)
{
        struct epoll_event events;
        int ret;

        memset(&events, 0, sizeof(events));
        ret = epoll_wait(epfd, &events, 1, cfg_poll_timeout);
        if (ret != 1)
                error(1, errno, "epoll_wait");
}

static void __poll(int fd)
{
        struct pollfd pollfd;
        int ret;

        memset(&pollfd, 0, sizeof(pollfd));
        pollfd.fd = fd;
        ret = poll(&pollfd, 1, cfg_poll_timeout);
        if (ret != 1)
                error(1, errno, "poll");
}

static void __recv_errmsg_cmsg(struct msghdr *msg, int payload_len)
{
        struct sock_extended_err *serr = NULL;
        struct scm_timestamping *tss = NULL;
        struct cmsghdr *cm;
        int batch = 0;

        for (cm = CMSG_FIRSTHDR(msg);
             cm && cm->cmsg_len;
             cm = CMSG_NXTHDR(msg, cm)) {
                if (cm->cmsg_level == SOL_SOCKET &&
                    cm->cmsg_type == SCM_TIMESTAMPING) {
                        tss = (void *) CMSG_DATA(cm);
                } else if ((cm->cmsg_level == SOL_IP &&
                            cm->cmsg_type == IP_RECVERR) ||
                           (cm->cmsg_level == SOL_IPV6 &&
                            cm->cmsg_type == IPV6_RECVERR) ||
                           (cm->cmsg_level == SOL_PACKET &&
                            cm->cmsg_type == PACKET_TX_TIMESTAMP)) {
                        serr = (void *) CMSG_DATA(cm);
                        if (serr->ee_errno != ENOMSG ||
                            serr->ee_origin != SO_EE_ORIGIN_TIMESTAMPING) {
                                fprintf(stderr, "unknown ip error %d %d\n",
                                                serr->ee_errno,
                                                serr->ee_origin);
                                serr = NULL;
                        }
                } else if (cm->cmsg_level == SOL_IP &&
                           cm->cmsg_type == IP_PKTINFO) {
                        struct in_pktinfo *info = (void *) CMSG_DATA(cm);
                        print_pktinfo(AF_INET, info->ipi_ifindex,
                                      &info->ipi_spec_dst, &info->ipi_addr);
                } else if (cm->cmsg_level == SOL_IPV6 &&
                           cm->cmsg_type == IPV6_PKTINFO) {
                        struct in6_pktinfo *info6 = (void *) CMSG_DATA(cm);
                        print_pktinfo(AF_INET6, info6->ipi6_ifindex,
                                      NULL, &info6->ipi6_addr);
                } else
                        fprintf(stderr, "unknown cmsg %d,%d\n",
                                        cm->cmsg_level, cm->cmsg_type);

                if (serr && tss) {
                        print_timestamp(tss, serr->ee_info, serr->ee_data,
                                        payload_len);
                        serr = NULL;
                        tss = NULL;
                        batch++;
                }
        }

        if (batch > 1) {
                fprintf(stderr, "batched %d timestamps\n", batch);
        } else if (!batch) {
                fprintf(stderr, "Failed to report timestamps\n");
                test_failed = true;
        }
}

static int recv_errmsg(int fd)
{
        static char ctrl[1024 /* overprovision*/];
        static struct msghdr msg;
        struct iovec entry;
        static char *data;
        int ret = 0;

        data = malloc(cfg_payload_len);
        if (!data)
                error(1, 0, "malloc");

        memset(&msg, 0, sizeof(msg));
        memset(&entry, 0, sizeof(entry));
        memset(ctrl, 0, sizeof(ctrl));

        entry.iov_base = data;
        entry.iov_len = cfg_payload_len;
        msg.msg_iov = &entry;
        msg.msg_iovlen = 1;
        msg.msg_name = NULL;
        msg.msg_namelen = 0;
        msg.msg_control = ctrl;
        msg.msg_controllen = sizeof(ctrl);

        ret = recvmsg(fd, &msg, MSG_ERRQUEUE);
        if (ret == -1 && errno != EAGAIN)
                error(1, errno, "recvmsg");

        if (ret >= 0) {
                __recv_errmsg_cmsg(&msg, ret);
                if (cfg_show_payload)
                        print_payload(data, cfg_payload_len);
        }

        free(data);
        return ret == -1;
}

static uint16_t get_ip_csum(const uint16_t *start, int num_words,
                            unsigned long sum)
{
        int i;

        for (i = 0; i < num_words; i++)
                sum += start[i];

        while (sum >> 16)
                sum = (sum & 0xFFFF) + (sum >> 16);

        return ~sum;
}

static uint16_t get_udp_csum(const struct udphdr *udph, int alen)
{
        unsigned long pseudo_sum, csum_len;
        const void *csum_start = udph;

        pseudo_sum = htons(IPPROTO_UDP);
        pseudo_sum += udph->len;

        /* checksum ip(v6) addresses + udp header + payload */
        csum_start -= alen * 2;
        csum_len = ntohs(udph->len) + alen * 2;

        return get_ip_csum(csum_start, csum_len >> 1, pseudo_sum);
}

static int fill_header_ipv4(void *p)
{
        struct iphdr *iph = p;

        memset(iph, 0, sizeof(*iph));

        iph->ihl        = 5;
        iph->version    = 4;
        iph->ttl        = 2;
        iph->saddr      = daddr.sin_addr.s_addr;        /* set for udp csum calc */
        iph->daddr      = daddr.sin_addr.s_addr;
        iph->protocol   = IPPROTO_UDP;

        /* kernel writes saddr, csum, len */

        return sizeof(*iph);
}

static int fill_header_ipv6(void *p)
{
        struct ipv6hdr *ip6h = p;

        memset(ip6h, 0, sizeof(*ip6h));

        ip6h->version           = 6;
        ip6h->payload_len       = htons(sizeof(struct udphdr) + cfg_payload_len);
        ip6h->nexthdr           = IPPROTO_UDP;
        ip6h->hop_limit         = 64;

        ip6h->saddr             = daddr6.sin6_addr;
        ip6h->daddr             = daddr6.sin6_addr;

        /* kernel does not write saddr in case of ipv6 */

        return sizeof(*ip6h);
}

static void fill_header_udp(void *p, bool is_ipv4)
{
        struct udphdr *udph = p;

        udph->source = ntohs(dest_port + 1);    /* spoof */
        udph->dest   = ntohs(dest_port);
        udph->len    = ntohs(sizeof(*udph) + cfg_payload_len);
        udph->check  = 0;

        udph->check  = get_udp_csum(udph, is_ipv4 ? sizeof(struct in_addr) :
                                                    sizeof(struct in6_addr));
}

static void do_test(int family, unsigned int report_opt)
{
        char control[2 * CMSG_SPACE(sizeof(uint32_t))];
        struct sockaddr_ll laddr;
        unsigned int sock_opt;
        struct cmsghdr *cmsg;
        struct msghdr msg;
        struct iovec iov;
        char *buf;
        int fd, i, val = 1, total_len, epfd = 0;

        init_timing_event(&usr_enq);
        init_timing_event(&usr_snd);
        init_timing_event(&usr_ack);

        total_len = cfg_payload_len;
        if (cfg_use_pf_packet || cfg_proto == SOCK_RAW) {
                total_len += sizeof(struct udphdr);
                if (cfg_use_pf_packet || cfg_ipproto == IPPROTO_RAW) {
                        if (family == PF_INET)
                                total_len += sizeof(struct iphdr);
                        else
                                total_len += sizeof(struct ipv6hdr);
                }
                /* special case, only rawv6_sendmsg:
                 * pass proto in sin6_port if not connected
                 * also see ANK comment in net/ipv4/raw.c
                 */
                daddr6.sin6_port = htons(cfg_ipproto);
        }

        buf = malloc(total_len);
        if (!buf)
                error(1, 0, "malloc");

        fd = socket(cfg_use_pf_packet ? PF_PACKET : family,
                    cfg_proto, cfg_ipproto);
        if (fd < 0)
                error(1, errno, "socket");

        if (cfg_use_epoll) {
                struct epoll_event ev;

                memset(&ev, 0, sizeof(ev));
                ev.data.fd = fd;
                if (cfg_epollet)
                        ev.events |= EPOLLET;
                epfd = epoll_create(1);
                if (epfd <= 0)
                        error(1, errno, "epoll_create");
                if (epoll_ctl(epfd, EPOLL_CTL_ADD, fd, &ev))
                        error(1, errno, "epoll_ctl");
        }

        /* reset expected key on each new socket */
        saved_tskey = -1;

        if (cfg_proto == SOCK_STREAM) {
                if (setsockopt(fd, IPPROTO_TCP, TCP_NODELAY,
                               (char*) &val, sizeof(val)))
                        error(1, 0, "setsockopt no nagle");

                if (family == PF_INET) {
                        if (connect(fd, (void *) &daddr, sizeof(daddr)))
                                error(1, errno, "connect ipv4");
                } else {
                        if (connect(fd, (void *) &daddr6, sizeof(daddr6)))
                                error(1, errno, "connect ipv6");
                }
        }

        if (cfg_do_pktinfo) {
                if (family == AF_INET6) {
                        if (setsockopt(fd, SOL_IPV6, IPV6_RECVPKTINFO,
                                       &val, sizeof(val)))
                                error(1, errno, "setsockopt pktinfo ipv6");
                } else {
                        if (setsockopt(fd, SOL_IP, IP_PKTINFO,
                                       &val, sizeof(val)))
                                error(1, errno, "setsockopt pktinfo ipv4");
                }
        }

        sock_opt = SOF_TIMESTAMPING_SOFTWARE |
                   SOF_TIMESTAMPING_OPT_CMSG |
                   SOF_TIMESTAMPING_OPT_ID;

        if (!cfg_use_cmsg)
                sock_opt |= report_opt;

        if (cfg_loop_nodata)
                sock_opt |= SOF_TIMESTAMPING_OPT_TSONLY;

        if (setsockopt(fd, SOL_SOCKET, SO_TIMESTAMPING,
                       (char *) &sock_opt, sizeof(sock_opt)))
                error(1, 0, "setsockopt timestamping");

        for (i = 0; i < cfg_num_pkts; i++) {
                memset(&msg, 0, sizeof(msg));
                memset(buf, 'a' + i, total_len);

                if (cfg_use_pf_packet || cfg_proto == SOCK_RAW) {
                        int off = 0;

                        if (cfg_use_pf_packet || cfg_ipproto == IPPROTO_RAW) {
                                if (family == PF_INET)
                                        off = fill_header_ipv4(buf);
                                else
                                        off = fill_header_ipv6(buf);
                        }

                        fill_header_udp(buf + off, family == PF_INET);
                }

                iov.iov_base = buf;
                iov.iov_len = total_len;

                if (cfg_proto != SOCK_STREAM) {
                        if (cfg_use_pf_packet) {
                                memset(&laddr, 0, sizeof(laddr));

                                laddr.sll_family        = AF_PACKET;
                                laddr.sll_ifindex       = 1;
                                laddr.sll_protocol      = htons(family == AF_INET ? ETH_P_IP : ETH_P_IPV6);
                                laddr.sll_halen         = ETH_ALEN;

                                msg.msg_name = (void *)&laddr;
                                msg.msg_namelen = sizeof(laddr);
                        } else if (family == PF_INET) {
                                msg.msg_name = (void *)&daddr;
                                msg.msg_namelen = sizeof(daddr);
                        } else {
                                msg.msg_name = (void *)&daddr6;
                                msg.msg_namelen = sizeof(daddr6);
                        }
                }

                msg.msg_iov = &iov;
                msg.msg_iovlen = 1;

                if (cfg_use_cmsg || cfg_use_cmsg_opt_id) {
                        memset(control, 0, sizeof(control));

                        msg.msg_control = control;
                        msg.msg_controllen = cfg_use_cmsg * CMSG_SPACE(sizeof(uint32_t));
                        msg.msg_controllen += cfg_use_cmsg_opt_id * CMSG_SPACE(sizeof(uint32_t));

                        cmsg = NULL;
                        if (cfg_use_cmsg) {
                                cmsg = CMSG_FIRSTHDR(&msg);
                                cmsg->cmsg_level = SOL_SOCKET;
                                cmsg->cmsg_type = SO_TIMESTAMPING;
                                cmsg->cmsg_len = CMSG_LEN(sizeof(uint32_t));

                                *((uint32_t *)CMSG_DATA(cmsg)) = report_opt;
                        }
                        if (cfg_use_cmsg_opt_id) {
                                cmsg = cmsg ? CMSG_NXTHDR(&msg, cmsg) : CMSG_FIRSTHDR(&msg);
                                cmsg->cmsg_level = SOL_SOCKET;
                                cmsg->cmsg_type = SCM_TS_OPT_ID;
                                cmsg->cmsg_len = CMSG_LEN(sizeof(uint32_t));

                                *((uint32_t *)CMSG_DATA(cmsg)) = ts_opt_id;
                                saved_tskey = ts_opt_id;
                        }

                }

                record_timestamp_usr();

                val = sendmsg(fd, &msg, 0);
                if (val != total_len)
                        error(1, errno, "send");

                __print_timestamp("  USR", &ts_usr, 0, 0);

                /* wait for all errors to be queued, else ACKs arrive OOO */
                if (cfg_sleep_usec)
                        usleep(cfg_sleep_usec);

                if (!cfg_busy_poll) {
                        if (cfg_use_epoll)
                                __epoll(epfd);
                        else
                                __poll(fd);
                }

                while (!recv_errmsg(fd)) {}
        }

        print_timing_event("USR-ENQ", &usr_enq);
        print_timing_event("USR-SND", &usr_snd);
        print_timing_event("USR-ACK", &usr_ack);

        if (close(fd))
                error(1, errno, "close");

        free(buf);
        usleep(100 * NSEC_PER_USEC);
}

static void __attribute__((noreturn)) usage(const char *filepath)
{
        fprintf(stderr, "\nUsage: %s [options] hostname\n"
                        "\nwhere options are:\n"
                        "  -4:   only IPv4\n"
                        "  -6:   only IPv6\n"
                        "  -h:   show this message\n"
                        "  -b:   busy poll to read from error queue\n"
                        "  -c N: number of packets for each test\n"
                        "  -C:   use cmsg to set tstamp recording options\n"
                        "  -e:   use level-triggered epoll() instead of poll()\n"
                        "  -E:   use event-triggered epoll() instead of poll()\n"
                        "  -F:   poll()/epoll() waits forever for an event\n"
                        "  -I:   request PKTINFO\n"
                        "  -l N: send N bytes at a time\n"
                        "  -L    listen on hostname and port\n"
                        "  -n:   set no-payload option\n"
                        "  -N:   print timestamps and durations in nsec (instead of usec)\n"
                        "  -o N: use SCM_TS_OPT_ID control message to provide N as tskey\n"
                        "  -p N: connect to port N\n"
                        "  -P:   use PF_PACKET\n"
                        "  -r:   use raw\n"
                        "  -R:   use raw (IP_HDRINCL)\n"
                        "  -S N: usec to sleep before reading error queue\n"
                        "  -t N: tolerance (usec) for timestamp validation\n"
                        "  -u:   use udp\n"
                        "  -v:   validate SND delay (usec)\n"
                        "  -V:   validate ACK delay (usec)\n"
                        "  -x:   show payload (up to 70 bytes)\n",
                        filepath);
        exit(1);
}

static void parse_opt(int argc, char **argv)
{
        int proto_count = 0;
        int c;

        while ((c = getopt(argc, argv,
                                "46bc:CeEFhIl:LnNo:p:PrRS:t:uv:V:x")) != -1) {
                switch (c) {
                case '4':
                        do_ipv6 = 0;
                        break;
                case '6':
                        do_ipv4 = 0;
                        break;
                case 'b':
                        cfg_busy_poll = true;
                        break;
                case 'c':
                        cfg_num_pkts = strtoul(optarg, NULL, 10);
                        break;
                case 'C':
                        cfg_use_cmsg = true;
                        break;
                case 'e':
                        cfg_use_epoll = true;
                        break;
                case 'E':
                        cfg_use_epoll = true;
                        cfg_epollet = true;
                case 'F':
                        cfg_poll_timeout = -1;
                        break;
                case 'I':
                        cfg_do_pktinfo = true;
                        break;
                case 'l':
                        cfg_payload_len = strtoul(optarg, NULL, 10);
                        break;
                case 'L':
                        cfg_do_listen = true;
                        break;
                case 'n':
                        cfg_loop_nodata = true;
                        break;
                case 'N':
                        cfg_print_nsec = true;
                        break;
                case 'o':
                        ts_opt_id = strtoul(optarg, NULL, 10);
                        cfg_use_cmsg_opt_id = true;
                        break;
                case 'p':
                        dest_port = strtoul(optarg, NULL, 10);
                        break;
                case 'P':
                        proto_count++;
                        cfg_use_pf_packet = true;
                        cfg_proto = SOCK_DGRAM;
                        cfg_ipproto = 0;
                        break;
                case 'r':
                        proto_count++;
                        cfg_proto = SOCK_RAW;
                        cfg_ipproto = IPPROTO_UDP;
                        break;
                case 'R':
                        proto_count++;
                        cfg_proto = SOCK_RAW;
                        cfg_ipproto = IPPROTO_RAW;
                        break;
                case 'S':
                        cfg_sleep_usec = strtoul(optarg, NULL, 10);
                        break;
                case 't':
                        cfg_delay_tolerance_usec = strtoul(optarg, NULL, 10);
                        break;
                case 'u':
                        proto_count++;
                        cfg_proto = SOCK_DGRAM;
                        cfg_ipproto = IPPROTO_UDP;
                        break;
                case 'v':
                        cfg_delay_snd = strtoul(optarg, NULL, 10);
                        break;
                case 'V':
                        cfg_delay_ack = strtoul(optarg, NULL, 10);
                        break;
                case 'x':
                        cfg_show_payload = true;
                        break;
                case 'h':
                default:
                        usage(argv[0]);
                }
        }

        if (!cfg_payload_len)
                error(1, 0, "payload may not be nonzero");
        if (cfg_proto != SOCK_STREAM && cfg_payload_len > 1472)
                error(1, 0, "udp packet might exceed expected MTU");
        if (!do_ipv4 && !do_ipv6)
                error(1, 0, "pass -4 or -6, not both");
        if (proto_count > 1)
                error(1, 0, "pass -P, -r, -R or -u, not multiple");
        if (cfg_do_pktinfo && cfg_use_pf_packet)
                error(1, 0, "cannot ask for pktinfo over pf_packet");
        if (cfg_busy_poll && cfg_use_epoll)
                error(1, 0, "pass epoll or busy_poll, not both");
        if (cfg_proto == SOCK_STREAM && cfg_use_cmsg_opt_id)
                error(1, 0, "TCP sockets don't support SCM_TS_OPT_ID");

        if (optind != argc - 1)
                error(1, 0, "missing required hostname argument");
}

static void resolve_hostname(const char *hostname)
{
        struct addrinfo hints = { .ai_family = do_ipv4 ? AF_INET : AF_INET6 };
        struct addrinfo *addrs, *cur;
        int have_ipv4 = 0, have_ipv6 = 0;

retry:
        if (getaddrinfo(hostname, NULL, &hints, &addrs))
                error(1, errno, "getaddrinfo");

        cur = addrs;
        while (cur && !have_ipv4 && !have_ipv6) {
                if (!have_ipv4 && cur->ai_family == AF_INET) {
                        memcpy(&daddr, cur->ai_addr, sizeof(daddr));
                        daddr.sin_port = htons(dest_port);
                        have_ipv4 = 1;
                }
                else if (!have_ipv6 && cur->ai_family == AF_INET6) {
                        memcpy(&daddr6, cur->ai_addr, sizeof(daddr6));
                        daddr6.sin6_port = htons(dest_port);
                        have_ipv6 = 1;
                }
                cur = cur->ai_next;
        }
        if (addrs)
                freeaddrinfo(addrs);

        if (do_ipv6 && hints.ai_family != AF_INET6) {
                hints.ai_family = AF_INET6;
                goto retry;
        }

        do_ipv4 &= have_ipv4;
        do_ipv6 &= have_ipv6;
}

static void do_listen(int family, void *addr, int alen)
{
        int fd, type;

        type = cfg_proto == SOCK_RAW ? SOCK_DGRAM : cfg_proto;

        fd = socket(family, type, 0);
        if (fd == -1)
                error(1, errno, "socket rx");

        if (bind(fd, addr, alen))
                error(1, errno, "bind rx");

        if (type == SOCK_STREAM && listen(fd, 10))
                error(1, errno, "listen rx");

        /* leave fd open, will be closed on process exit.
         * this enables connect() to succeed and avoids icmp replies
         */
}

static void do_main(int family)
{
        fprintf(stderr, "family:       %s %s\n",
                        family == PF_INET ? "INET" : "INET6",
                        cfg_use_pf_packet ? "(PF_PACKET)" : "");

        fprintf(stderr, "test SND\n");
        do_test(family, SOF_TIMESTAMPING_TX_SOFTWARE);

        fprintf(stderr, "test ENQ\n");
        do_test(family, SOF_TIMESTAMPING_TX_SCHED);

        fprintf(stderr, "test ENQ + SND\n");
        do_test(family, SOF_TIMESTAMPING_TX_SCHED |
                        SOF_TIMESTAMPING_TX_SOFTWARE);

        if (cfg_proto == SOCK_STREAM) {
                fprintf(stderr, "\ntest ACK\n");
                do_test(family, SOF_TIMESTAMPING_TX_ACK);

                fprintf(stderr, "\ntest SND + ACK\n");
                do_test(family, SOF_TIMESTAMPING_TX_SOFTWARE |
                                SOF_TIMESTAMPING_TX_ACK);

                fprintf(stderr, "\ntest ENQ + SND + ACK\n");
                do_test(family, SOF_TIMESTAMPING_TX_SCHED |
                                SOF_TIMESTAMPING_TX_SOFTWARE |
                                SOF_TIMESTAMPING_TX_ACK);
        }
}

const char *sock_names[] = { NULL, "TCP", "UDP", "RAW" };

int main(int argc, char **argv)
{
        if (argc == 1)
                usage(argv[0]);

        parse_opt(argc, argv);
        resolve_hostname(argv[argc - 1]);

        fprintf(stderr, "protocol:     %s\n", sock_names[cfg_proto]);
        fprintf(stderr, "payload:      %u\n", cfg_payload_len);
        fprintf(stderr, "server port:  %u\n", dest_port);
        fprintf(stderr, "\n");

        if (do_ipv4) {
                if (cfg_do_listen)
                        do_listen(PF_INET, &daddr, sizeof(daddr));
                do_main(PF_INET);
        }

        if (do_ipv6) {
                if (cfg_do_listen)
                        do_listen(PF_INET6, &daddr6, sizeof(daddr6));
                do_main(PF_INET6);
        }

        return test_failed;
}