1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2023 Igor Ostapenko <pm@igoro.pro>
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28/* Used by tests like divert-to.sh */
29
30#include <errno.h>
31#include <stdlib.h>
32#include <stdbool.h>
33#include <err.h>
34#include <sysexits.h>
35#include <string.h>
36
37#include <sys/types.h>
38#include <sys/socket.h>
39#include <netinet/in.h>
40#include <netinet/ip.h>
41
42
43struct context {
44	unsigned short divert_port;
45	bool divert_back;
46
47	int fd;
48	struct sockaddr_in sin;
49	socklen_t sin_len;
50	char pkt[IP_MAXPACKET];
51	ssize_t pkt_n;
52};
53
54static void
55init(struct context *c)
56{
57	c->fd = socket(PF_DIVERT, SOCK_RAW, 0);
58	if (c->fd == -1)
59		errx(EX_OSERR, "init: Cannot create divert socket.");
60
61	memset(&c->sin, 0, sizeof(c->sin));
62	c->sin.sin_family = AF_INET;
63	c->sin.sin_port = htons(c->divert_port);
64	c->sin.sin_addr.s_addr = INADDR_ANY;
65	c->sin_len = sizeof(struct sockaddr_in);
66
67	if (bind(c->fd, (struct sockaddr *) &c->sin, c->sin_len) != 0)
68		errx(EX_OSERR, "init: Cannot bind divert socket.");
69}
70
71static ssize_t
72recv_pkt(struct context *c)
73{
74	fd_set readfds;
75	struct timeval timeout;
76	int s;
77
78	FD_ZERO(&readfds);
79	FD_SET(c->fd, &readfds);
80	timeout.tv_sec = 3;
81	timeout.tv_usec = 0;
82
83	s = select(c->fd + 1, &readfds, 0, 0, &timeout);
84	if (s == -1)
85		errx(EX_IOERR, "recv_pkt: select() errors.");
86	if (s != 1) // timeout
87		return -1;
88
89	c->pkt_n = recvfrom(c->fd, c->pkt, sizeof(c->pkt), 0,
90	    (struct sockaddr *) &c->sin, &c->sin_len);
91	if (c->pkt_n == -1)
92		errx(EX_IOERR, "recv_pkt: recvfrom() errors.");
93
94	return (c->pkt_n);
95}
96
97static void
98send_pkt(struct context *c)
99{
100	ssize_t n;
101	char errstr[32];
102
103	n = sendto(c->fd, c->pkt, c->pkt_n, 0,
104	    (struct sockaddr *) &c->sin, c->sin_len);
105	if (n == -1) {
106		strerror_r(errno, errstr, sizeof(errstr));
107		errx(EX_IOERR, "send_pkt: sendto() errors: %d %s.", errno, errstr);
108	}
109	if (n != c->pkt_n)
110		errx(EX_IOERR, "send_pkt: sendto() sent %zd of %zd bytes.",
111		    n, c->pkt_n);
112}
113
114int
115main(int argc, char *argv[])
116{
117	struct context c;
118	int npkt;
119
120	if (argc < 2)
121		errx(EX_USAGE,
122		    "Usage: %s <divert-port> [divert-back]", argv[0]);
123
124	memset(&c, 0, sizeof(struct context));
125
126	c.divert_port = (unsigned short) strtol(argv[1], NULL, 10);
127	if (c.divert_port == 0)
128		errx(EX_USAGE, "divert port is not defined.");
129
130	if (argc >= 3 && strcmp(argv[2], "divert-back") == 0)
131		c.divert_back = true;
132
133
134	init(&c);
135
136	npkt = 0;
137	while (recv_pkt(&c) > 0) {
138		if (c.divert_back)
139			send_pkt(&c);
140		npkt++;
141		if (npkt >= 10)
142			break;
143	}
144
145	if (npkt != 1)
146		errx(EXIT_FAILURE, "%d: npkt=%d.", c.divert_port, npkt);
147
148	return EXIT_SUCCESS;
149}
150