--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Test the SO_TXTIME API
+ *
+ * Takes two streams of { payload, delivery time }[], one input and one output.
+ * Sends the input stream and verifies arrival matches the output stream.
+ * The two streams can differ due to out-of-order delivery and drops.
+ */
+
+#define _GNU_SOURCE
+
+#include <arpa/inet.h>
+#include <error.h>
+#include <errno.h>
+#include <linux/net_tstamp.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <time.h>
+#include <unistd.h>
+
+static int cfg_clockid = CLOCK_TAI;
+static bool cfg_do_ipv4;
+static bool cfg_do_ipv6;
+static uint16_t cfg_port = 8000;
+static int cfg_variance_us = 2000;
+
+static uint64_t glob_tstart;
+
+/* encode one timed transmission (of a 1B payload) */
+struct timed_send {
+ char data;
+ int64_t delay_us;
+};
+
+#define MAX_NUM_PKT 8
+static struct timed_send cfg_in[MAX_NUM_PKT];
+static struct timed_send cfg_out[MAX_NUM_PKT];
+static int cfg_num_pkt;
+
+static uint64_t gettime_ns(void)
+{
+ struct timespec ts;
+
+ if (clock_gettime(cfg_clockid, &ts))
+ error(1, errno, "gettime");
+
+ return ts.tv_sec * (1000ULL * 1000 * 1000) + ts.tv_nsec;
+}
+
+static void do_send_one(int fdt, struct timed_send *ts)
+{
+ char control[CMSG_SPACE(sizeof(uint64_t))];
+ struct msghdr msg = {0};
+ struct iovec iov = {0};
+ struct cmsghdr *cm;
+ uint64_t tdeliver;
+ int ret;
+
+ iov.iov_base = &ts->data;
+ iov.iov_len = 1;
+
+ msg.msg_iov = &iov;
+ msg.msg_iovlen = 1;
+
+ if (ts->delay_us >= 0) {
+ memset(control, 0, sizeof(control));
+ msg.msg_control = &control;
+ msg.msg_controllen = sizeof(control);
+
+ tdeliver = glob_tstart + ts->delay_us * 1000;
+
+ cm = CMSG_FIRSTHDR(&msg);
+ cm->cmsg_level = SOL_SOCKET;
+ cm->cmsg_type = SCM_TXTIME;
+ cm->cmsg_len = CMSG_LEN(sizeof(tdeliver));
+ memcpy(CMSG_DATA(cm), &tdeliver, sizeof(tdeliver));
+ }
+
+ ret = sendmsg(fdt, &msg, 0);
+ if (ret == -1)
+ error(1, errno, "write");
+ if (ret == 0)
+ error(1, 0, "write: 0B");
+
+}
+
+static void do_recv_one(int fdr, struct timed_send *ts)
+{
+ int64_t tstop, texpect;
+ char rbuf[2];
+ int ret;
+
+ ret = recv(fdr, rbuf, sizeof(rbuf), 0);
+ if (ret == -1)
+ error(1, errno, "read");
+ if (ret != 1)
+ error(1, 0, "read: %dB", ret);
+
+ tstop = (gettime_ns() - glob_tstart) / 1000;
+ texpect = ts->delay_us >= 0 ? ts->delay_us : 0;
+
+ fprintf(stderr, "payload:%c delay:%ld expected:%ld (us)\n",
+ rbuf[0], tstop, texpect);
+
+ if (rbuf[0] != ts->data)
+ error(1, 0, "payload mismatch. expected %c", ts->data);
+
+ if (labs(tstop - texpect) > cfg_variance_us)
+ error(1, 0, "exceeds variance (%d us)", cfg_variance_us);
+}
+
+static void do_recv_verify_empty(int fdr)
+{
+ char rbuf[1];
+ int ret;
+
+ ret = recv(fdr, rbuf, sizeof(rbuf), 0);
+ if (ret != -1 || errno != EAGAIN)
+ error(1, 0, "recv: not empty as expected (%d, %d)", ret, errno);
+}
+
+static void setsockopt_txtime(int fd)
+{
+ struct sock_txtime so_txtime_val = { .clockid = cfg_clockid };
+ struct sock_txtime so_txtime_val_read = { 0 };
+ socklen_t vallen = sizeof(so_txtime_val);
+
+ if (setsockopt(fd, SOL_SOCKET, SO_TXTIME,
+ &so_txtime_val, sizeof(so_txtime_val)))
+ error(1, errno, "setsockopt txtime");
+
+ if (getsockopt(fd, SOL_SOCKET, SO_TXTIME,
+ &so_txtime_val_read, &vallen))
+ error(1, errno, "getsockopt txtime");
+
+ if (vallen != sizeof(so_txtime_val) ||
+ memcmp(&so_txtime_val, &so_txtime_val_read, vallen))
+ error(1, 0, "getsockopt txtime: mismatch");
+}
+
+static int setup_tx(struct sockaddr *addr, socklen_t alen)
+{
+ int fd;
+
+ fd = socket(addr->sa_family, SOCK_DGRAM, 0);
+ if (fd == -1)
+ error(1, errno, "socket t");
+
+ if (connect(fd, addr, alen))
+ error(1, errno, "connect");
+
+ setsockopt_txtime(fd);
+
+ return fd;
+}
+
+static int setup_rx(struct sockaddr *addr, socklen_t alen)
+{
+ struct timeval tv = { .tv_usec = 100 * 1000 };
+ int fd;
+
+ fd = socket(addr->sa_family, SOCK_DGRAM, 0);
+ if (fd == -1)
+ error(1, errno, "socket r");
+
+ if (bind(fd, addr, alen))
+ error(1, errno, "bind");
+
+ if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv)))
+ error(1, errno, "setsockopt rcv timeout");
+
+ return fd;
+}
+
+static void do_test(struct sockaddr *addr, socklen_t alen)
+{
+ int fdt, fdr, i;
+
+ fprintf(stderr, "\nSO_TXTIME ipv%c clock %s\n",
+ addr->sa_family == PF_INET ? '4' : '6',
+ cfg_clockid == CLOCK_TAI ? "tai" : "monotonic");
+
+ fdt = setup_tx(addr, alen);
+ fdr = setup_rx(addr, alen);
+
+ glob_tstart = gettime_ns();
+
+ for (i = 0; i < cfg_num_pkt; i++)
+ do_send_one(fdt, &cfg_in[i]);
+ for (i = 0; i < cfg_num_pkt; i++)
+ do_recv_one(fdr, &cfg_out[i]);
+
+ do_recv_verify_empty(fdr);
+
+ if (close(fdr))
+ error(1, errno, "close r");
+ if (close(fdt))
+ error(1, errno, "close t");
+}
+
+static int parse_io(const char *optarg, struct timed_send *array)
+{
+ char *arg, *tok;
+ int aoff = 0;
+
+ arg = strdup(optarg);
+ if (!arg)
+ error(1, errno, "strdup");
+
+ while ((tok = strtok(arg, ","))) {
+ arg = NULL; /* only pass non-zero on first call */
+
+ if (aoff / 2 == MAX_NUM_PKT)
+ error(1, 0, "exceeds max pkt count (%d)", MAX_NUM_PKT);
+
+ if (aoff & 1) { /* parse delay */
+ array->delay_us = strtol(tok, NULL, 0) * 1000;
+ array++;
+ } else { /* parse character */
+ array->data = tok[0];
+ }
+
+ aoff++;
+ }
+
+ free(arg);
+
+ return aoff / 2;
+}
+
+static void parse_opts(int argc, char **argv)
+{
+ int c, ilen, olen;
+
+ while ((c = getopt(argc, argv, "46c:")) != -1) {
+ switch (c) {
+ case '4':
+ cfg_do_ipv4 = true;
+ break;
+ case '6':
+ cfg_do_ipv6 = true;
+ break;
+ case 'c':
+ if (!strcmp(optarg, "tai"))
+ cfg_clockid = CLOCK_TAI;
+ else if (!strcmp(optarg, "monotonic") ||
+ !strcmp(optarg, "mono"))
+ cfg_clockid = CLOCK_MONOTONIC;
+ else
+ error(1, 0, "unknown clock id %s", optarg);
+ break;
+ default:
+ error(1, 0, "parse error at %d", optind);
+ }
+ }
+
+ if (argc - optind != 2)
+ error(1, 0, "Usage: %s [-46] -c <clock> <in> <out>", argv[0]);
+
+ ilen = parse_io(argv[optind], cfg_in);
+ olen = parse_io(argv[optind + 1], cfg_out);
+ if (ilen != olen)
+ error(1, 0, "i/o streams len mismatch (%d, %d)\n", ilen, olen);
+ cfg_num_pkt = ilen;
+}
+
+int main(int argc, char **argv)
+{
+ parse_opts(argc, argv);
+
+ if (cfg_do_ipv6) {
+ struct sockaddr_in6 addr6 = {0};
+
+ addr6.sin6_family = AF_INET6;
+ addr6.sin6_port = htons(cfg_port);
+ addr6.sin6_addr = in6addr_loopback;
+ do_test((void *)&addr6, sizeof(addr6));
+ }
+
+ if (cfg_do_ipv4) {
+ struct sockaddr_in addr4 = {0};
+
+ addr4.sin_family = AF_INET;
+ addr4.sin_port = htons(cfg_port);
+ addr4.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
+ do_test((void *)&addr4, sizeof(addr4));
+ }
+
+ return 0;
+}