1/*-
2 * Copyright (c) 2006, Andrea Bittau <a.bittau@cs.ucl.ac.uk>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD$
27 */
28#include <sys/uio.h>
29#include <sys/types.h>
30#include <sys/socket.h>
31#include <netinet/in_systm.h>
32#include <netinet/in.h>
33#include <arpa/inet.h>
34#include <netinet/ip.h>
35#include <stdio.h>
36#include <stdlib.h>
37#include <string.h>
38#include <unistd.h>
39#include <fcntl.h>
40#include <errno.h>
41#include <signal.h>
42#include <err.h>
43
44void hexdump(void *b, int len)
45{
46        unsigned char *p = (unsigned char*) b;
47
48        while (len--)
49                printf("%.2X ", *p++);
50        printf("\n");
51}
52
53int handle_data(int dude, char *buf, int len)
54{
55	struct ip *ih;
56	unsigned short id;
57	char tmp[4];
58	struct iovec iov[2];
59	struct msghdr mh;
60
61	ih = (struct ip*) buf;
62
63	/* XXX IP FRAGS */
64
65	/* filter */
66	if (ih->ip_p != 0)
67		return 0;
68
69	if (ih->ip_hl != 5)
70		return 0;
71
72	/* get info */
73	id = ih->ip_id;
74	len -= 20;
75	buf += 20;
76	printf("Got %d bytes [%d]\n", len, ntohs(id));
77#if 0
78	hexdump(buf, len);
79#endif
80
81	/* prepare packet */
82	memcpy(tmp, &id, 2);
83	id = htons(len);
84	memcpy(&tmp[2], &id, 2);
85
86	iov[0].iov_base = tmp;
87	iov[0].iov_len = 4;
88	iov[1].iov_base = buf;
89	iov[1].iov_len = len;
90
91	memset(&mh, 0, sizeof(mh));
92	mh.msg_iov = iov;
93	mh.msg_iovlen = sizeof(iov)/sizeof(struct iovec);
94
95	/* write */
96	if (sendmsg(dude, &mh, 0) != (4 + len))
97		return -1;
98	return 0;
99}
100
101void handle_dude(int dude, int raw)
102{
103	char buf[4096];
104	int rd;
105
106	while (1) {
107		rd = recv(raw, buf, sizeof(buf), 0);
108		if (rd == -1)
109			err(1, "recv()");
110
111		if (handle_data(dude, buf, rd) == -1)
112			return;
113	}
114}
115
116void hand(int s)
117{
118	printf("sigpipe\n");
119}
120
121int main(int argc, char *argv[])
122{
123	int s, dude;
124	struct sockaddr_in s_in;
125	int len;
126	int raw;
127
128	memset(&s_in, 0, sizeof(&s_in));
129	s_in.sin_family = PF_INET;
130	s_in.sin_port = htons(666);
131	s_in.sin_addr.s_addr = INADDR_ANY;
132
133	if ((raw = socket(PF_INET, SOCK_RAW, 0)) == -1)
134		err(1, "socket()");
135
136	if ((s = socket(s_in.sin_family, SOCK_STREAM, IPPROTO_TCP)) == -1)
137		err(1, "socket()");
138
139	if (bind(s, (struct sockaddr*)&s_in, sizeof(s_in)) == -1)
140		err(1, "bind()");
141
142	if (listen(s, 5) == -1)
143		err(1, "listen()");
144
145	if (signal(SIGPIPE, hand) == SIG_ERR)
146		err(1, "signal()");
147
148	while (1) {
149		len = sizeof(s_in);
150		dude = accept(s, (struct sockaddr*)&s_in, &len);
151		if (dude == -1)
152			err(1, "accept()");
153
154		printf("Got dude %s\n", inet_ntoa(s_in.sin_addr));
155		handle_dude(dude, raw);
156		printf("Done\n");
157	}
158}
159