// SPDX-License-Identifier: GPL-2.0
#define _GNU_SOURCE
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <string.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdint.h>
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <strings.h>
#include <unistd.h>
#include <time.h>
#include <sys/ioctl.h>
#include <sys/random.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <netdb.h>
#include <netinet/in.h>
#include <linux/tcp.h>
#include <linux/sockios.h>
#ifndef IPPROTO_MPTCP
#define IPPROTO_MPTCP 262
#endif
#ifndef SOL_MPTCP
#define SOL_MPTCP 284
#endif
static int pf = AF_INET;
static int proto_tx = IPPROTO_MPTCP;
static int proto_rx = IPPROTO_MPTCP;
static void die_perror(const char *msg)
{
perror(msg);
exit(1);
}
static void die_usage(int r)
{
fprintf(stderr, "Usage: mptcp_inq [-6] [ -t tcp|mptcp ] [ -r tcp|mptcp]\n");
exit(r);
}
static void xerror(const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
vfprintf(stderr, fmt, ap);
va_end(ap);
fputc('\n', stderr);
exit(1);
}
static const char *getxinfo_strerr(int err)
{
if (err == EAI_SYSTEM)
return strerror(errno);
return gai_strerror(err);
}
static void xgetaddrinfo(const char *node, const char *service,
const struct addrinfo *hints,
struct addrinfo **res)
{
int err = getaddrinfo(node, service, hints, res);
if (err) {
const char *errstr = getxinfo_strerr(err);
fprintf(stderr, "Fatal: getaddrinfo(%s:%s): %s\n",
node ? node : "", service ? service : "", errstr);
exit(1);
}
}
static int sock_listen_mptcp(const char * const listenaddr,
const char * const port)
{
int sock = -1;
struct addrinfo hints = {
.ai_protocol = IPPROTO_TCP,
.ai_socktype = SOCK_STREAM,
.ai_flags = AI_PASSIVE | AI_NUMERICHOST
};
hints.ai_family = pf;
struct addrinfo *a, *addr;
int one = 1;
xgetaddrinfo(listenaddr, port, &hints, &addr);
hints.ai_family = pf;
for (a = addr; a; a = a->ai_next) {
sock = socket(a->ai_family, a->ai_socktype, proto_rx);
if (sock < 0)
continue;
if (-1 == setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &one,
sizeof(one)))
perror("setsockopt");
if (bind(sock, a->ai_addr, a->ai_addrlen) == 0)
break; /* success */
perror("bind");
close(sock);
sock = -1;
}
freeaddrinfo(addr);
if (sock < 0)
xerror("could not create listen socket");
if (listen(sock, 20))
die_perror("listen");
return sock;
}
static int sock_connect_mptcp(const char * const remoteaddr,
const char * const port, int proto)
{
struct addrinfo hints = {
.ai_protocol = IPPROTO_TCP,
.ai_socktype = SOCK_STREAM,
};
struct addrinfo *a, *addr;
int sock = -1;
hints.ai_family = pf;
xgetaddrinfo(remoteaddr, port, &hints, &addr);
for (a = addr; a; a = a->ai_next) {
sock = socket(a->ai_family, a->ai_socktype, proto);
if (sock < 0)
continue;
if (connect(sock, a->ai_addr, a->ai_addrlen) == 0)
break; /* success */
die_perror("connect");
}
if (sock < 0)
xerror("could not create connect socket");
freeaddrinfo(addr);
return sock;
}
static int protostr_to_num(const char *s)
{
if (strcasecmp(s, "tcp") == 0)
return IPPROTO_TCP;
if (strcasecmp(s, "mptcp") == 0)
return IPPROTO_MPTCP;
die_usage(1);
return 0;
}
static void parse_opts(int argc, char **argv)
{
int c;
while ((c = getopt(argc, argv, "h6t:r:")) != -1) {
switch (c) {
case 'h':
die_usage(0);
break;
case '6':
pf = AF_INET6;
break;
case 't':
proto_tx = protostr_to_num(optarg);
break;
case 'r':
proto_rx = protostr_to_num(optarg);
break;
default:
die_usage(1);
break;
}
}
}
/* wait up to timeout milliseconds */
static void wait_for_ack(int fd, int timeout, size_t total)
{
int i;
for (i = 0; i < timeout; i++) {
int nsd, ret, queued = -1;
struct timespec req;
ret = ioctl(fd, TIOCOUTQ, &queued);
if (ret < 0)
die_perror("TIOCOUTQ");
ret = ioctl(fd, SIOCOUTQNSD, &nsd);
if (ret < 0)
die_perror("SIOCOUTQNSD");
if ((size_t)queued > total)
xerror("TIOCOUTQ %u, but only %zu expected\n", queued, total);
assert(nsd <= queued);
if (queued == 0)
return;
/* wait for peer to ack rx of all data */
req.tv_sec = 0;
req.tv_nsec = 1 * 1000 * 1000ul; /* 1ms */
nanosleep(&req, NULL);
}
xerror("still tx data queued after %u ms\n", timeout);
}
static void connect_one_server(int fd, int unixfd)
{
size_t len, i, total, sent;
char buf[4096], buf2[4096];
ssize_t ret;
len = rand() % (sizeof(buf) - 1);
if (len < 128)
len = 128;
for (i = 0; i < len ; i++) {
buf[i] = rand() % 26;
buf[i] += 'A';
}
buf[i] = '\n';
/* un-block server */
ret = read(unixfd, buf2, 4);
assert(ret == 4);
assert(strncmp(buf2, "xmit", 4) == 0);
ret = write(unixfd, &len, sizeof(len));
assert(ret == (ssize_t)sizeof(len));
ret = write(fd, buf, len);
if (ret < 0)
die_perror("write");
if (ret != (ssize_t)len)
xerror("short write");
ret = read(unixfd, buf2, 4);
assert(strncmp(buf2, "huge", 4) == 0);
total = rand() % (16 * 1024 * 1024);
total += (1 * 1024 * 1024);
sent = total;
ret = write(unixfd, &total, sizeof(total));
assert(ret == (ssize_t)sizeof(total));
wait_for_ack(fd, 5000, len);
while (total > 0) {
if (total > sizeof(buf))
len = sizeof(buf);
else
len = total;
ret = write(fd, buf, len);
if (ret < 0)
die_perror("write");
total -= ret;
/* we don't have to care about buf content, only
* number of total bytes sent
*/
}
ret = read(unixfd, buf2, 4);
assert(ret == 4);
assert(strncmp(buf2, "shut", 4) == 0);
wait_for_ack(fd, 5000, sent);
ret = write(fd, buf, 1);
assert(ret == 1);
close(fd);
ret = write(unixfd, "closed", 6);
assert(ret == 6);
close(unixfd);
}
static void get_tcp_inq(struct msghdr *msgh, unsigned int *inqv)
{
struct cmsghdr *cmsg;
for (cmsg = CMSG_FIRSTHDR(msgh); cmsg ; cmsg = CMSG_NXTHDR(msgh, cmsg)) {
if (cmsg->cmsg_level == IPPROTO_TCP && cmsg->cmsg_type == TCP_CM_INQ) {
memcpy(inqv, CMSG_DATA(cmsg), sizeof(*inqv));
return;
}
}
xerror("could not find TCP_CM_INQ cmsg type");
}
static void process_one_client(int fd, int unixfd)
{
unsigned int tcp_inq;
size_t expect_len;
char msg_buf[4096];
char buf[4096];
char tmp[16];
struct iovec iov = {
.iov_base = buf,
.iov_len = 1,
};
struct msghdr msg = {
.msg_iov = &iov,
.msg_iovlen = 1,
.msg_control = msg_buf,
.msg_controllen = sizeof(msg_buf),
};
ssize_t ret, tot;
ret = write(unixfd, "xmit", 4);
assert(ret == 4);
ret = read(unixfd, &expect_len, sizeof(expect_len));
assert(ret == (ssize_t)sizeof(expect_len));
if (expect_len > sizeof(buf))
xerror("expect len %zu exceeds buffer size", expect_len);
for (;;) {
struct timespec req;
unsigned int queued;
ret = ioctl(fd, FIONREAD, &queued);
if (ret < 0)
die_perror("FIONREAD");
if (queued > expect_len)
xerror("FIONREAD returned %u, but only %zu expected\n",
queued, expect_len);
if (queued == expect_len)
break;
req.tv_sec = 0;
req.tv_nsec = 1000 * 1000ul;
nanosleep(&req, NULL);
}
/* read one byte, expect cmsg to return expected - 1 */
ret = recvmsg(fd, &msg, 0);
if (ret < 0)
die_perror("recvmsg");
if (msg.msg_controllen == 0)
xerror("msg_controllen is 0");
get_tcp_inq(&msg, &tcp_inq);
assert((size_t)tcp_inq == (expect_len - 1));
iov.iov_len = sizeof(buf);
ret = recvmsg(fd, &msg, 0);
if (ret < 0)
die_perror("recvmsg");
/* should have gotten exact remainder of all pending data */
assert(ret == (ssize_t)tcp_inq);
/* should be 0, all drained */
get_tcp_inq(&msg, &tcp_inq);
assert(tcp_inq == 0);
/* request a large swath of data. */
ret = write(unixfd, "huge", 4);
assert(ret == 4);
ret = read(unixfd, &expect_len, sizeof(expect_len));
assert(ret == (ssize_t)sizeof(expect_len));
/* peer should send us a few mb of data */
if (expect_len <= sizeof(buf))
xerror("expect len %zu too small\n", expect_len);
tot = 0;
do {
iov.iov_len = sizeof(buf);
ret = recvmsg(fd, &msg, 0);
if (ret < 0)
die_perror("recvmsg");
tot += ret;
get_tcp_inq(&msg, &tcp_inq);
if (tcp_inq > expect_len - tot)
xerror("inq %d, remaining %d total_len %d\n",
tcp_inq, expect_len - tot, (int)expect_len);
assert(tcp_inq <= expect_len - tot);
} while ((size_t)tot < expect_len);
ret = write(unixfd, "shut", 4);
assert(ret == 4);
/* wait for hangup. Should have received one more byte of data. */
ret = read(unixfd, tmp, sizeof(tmp));
assert(ret == 6);
assert(strncmp(tmp, "closed", 6) == 0);
sleep(1);
iov.iov_len = 1;
ret = recvmsg(fd, &msg, 0);
if (ret < 0)
die_perror("recvmsg");
assert(ret == 1);
get_tcp_inq(&msg, &tcp_inq);
/* tcp_inq should be 1 due to received fin. */
assert(tcp_inq == 1);
iov.iov_len = 1;
ret = recvmsg(fd, &msg, 0);
if (ret < 0)
die_perror("recvmsg");
/* expect EOF */
assert(ret == 0);
get_tcp_inq(&msg, &tcp_inq);
assert(tcp_inq == 1);
close(fd);
}
static int xaccept(int s)
{
int fd = accept(s, NULL, 0);
if (fd < 0)
die_perror("accept");
return fd;
}
static int server(int unixfd)
{
int fd = -1, r, on = 1;
switch (pf) {
case AF_INET:
fd = sock_listen_mptcp("127.0.0.1", "15432");
break;
case AF_INET6:
fd = sock_listen_mptcp("::1", "15432");
break;
default:
xerror("Unknown pf %d\n", pf);
break;
}
r = write(unixfd, "conn", 4);
assert(r == 4);
alarm(15);
r = xaccept(fd);
if (-1 == setsockopt(r, IPPROTO_TCP, TCP_INQ, &on, sizeof(on)))
die_perror("setsockopt");
process_one_client(r, unixfd);
return 0;
}
static int client(int unixfd)
{
int fd = -1;
alarm(15);
switch (pf) {
case AF_INET:
fd = sock_connect_mptcp("127.0.0.1", "15432", proto_tx);
break;
case AF_INET6:
fd = sock_connect_mptcp("::1", "15432", proto_tx);
break;
default:
xerror("Unknown pf %d\n", pf);
}
connect_one_server(fd, unixfd);
return 0;
}
static void init_rng(void)
{
unsigned int foo;
if (getrandom(&foo, sizeof(foo), 0) == -1) {
perror("getrandom");
exit(1);
}
srand(foo);
}
static pid_t xfork(void)
{
pid_t p = fork();
if (p < 0)
die_perror("fork");
else if (p == 0)
init_rng();
return p;
}
static int rcheck(int wstatus, const char *what)
{
if (WIFEXITED(wstatus)) {
if (WEXITSTATUS(wstatus) == 0)
return 0;
fprintf(stderr, "%s exited, status=%d\n", what, WEXITSTATUS(wstatus));
return WEXITSTATUS(wstatus);
} else if (WIFSIGNALED(wstatus)) {
xerror("%s killed by signal %d\n", what, WTERMSIG(wstatus));
} else if (WIFSTOPPED(wstatus)) {
xerror("%s stopped by signal %d\n", what, WSTOPSIG(wstatus));
}
return 111;
}
int main(int argc, char *argv[])
{
int e1, e2, wstatus;
pid_t s, c, ret;
int unixfds[2];
parse_opts(argc, argv);
e1 = socketpair(AF_UNIX, SOCK_DGRAM, 0, unixfds);
if (e1 < 0)
die_perror("pipe");
s = xfork();
if (s == 0)
return server(unixfds[1]);
close(unixfds[1]);
/* wait until server bound a socket */
e1 = read(unixfds[0], &e1, 4);
assert(e1 == 4);
c = xfork();
if (c == 0)
return client(unixfds[0]);
close(unixfds[0]);
ret = waitpid(s, &wstatus, 0);
if (ret == -1)
die_perror("waitpid");
e1 = rcheck(wstatus, "server");
ret = waitpid(c, &wstatus, 0);
if (ret == -1)
die_perror("waitpid");
e2 = rcheck(wstatus, "client");
return e1 ? e1 : e2;
}
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