sbpf.c revision 80486 
1/*
2 * (C)opyright 1995-1998 Darren Reed. (from tcplog)
3 *
4 * See the IPFILTER.LICENCE file for details on licencing.
5 *
6 */
7#include <stdio.h>
8#include <netdb.h>
9#include <ctype.h>
10#include <signal.h>
11#include <errno.h>
12#include <sys/types.h>
13#include <sys/param.h>
14#include <sys/mbuf.h>
15#include <sys/time.h>
16#include <sys/timeb.h>
17#include <sys/socket.h>
18#include <sys/file.h>
19#include <sys/ioctl.h>
20#if BSD < 199103
21#include <sys/fcntlcom.h>
22#endif
23#include <sys/dir.h>
24#include <net/bpf.h>
25
26#include <net/if.h>
27#include <netinet/in.h>
28#include <netinet/in_systm.h>
29#include <netinet/ip.h>
30#include <netinet/if_ether.h>
31#include <netinet/ip_var.h>
32#include <netinet/udp.h>
33#include <netinet/udp_var.h>
34#include <netinet/tcp.h>
35#include <netinet/tcpip.h>
36#include "ip_compat.h"
37
38#ifndef	lint
39static	char	sbpf[] = "@(#)sbpf.c	1.2 12/3/95 (C)1995 Darren Reed";
40#endif
41
42/*
43(000) ldh      [12]
44(001) jeq      #0x800	   jt 2	jf 5
45(002) ldb      [23]
46(003) jeq      #0x6	     jt 4	jf 5
47(004) ret      #68
48(005) ret      #0
49*/
50struct	bpf_insn filter[] = {
51/* 0. */	{ BPF_LD|BPF_H|BPF_ABS,		0, 0, 12 },
52/* 1. */	{ BPF_JMP|BPF_JEQ,		0, 3, 0x0800 },
53/* 2. */	{ BPF_LD|BPF_B|BPF_ABS,		0, 0, 23 },
54/* 3. */	{ BPF_JMP|BPF_JEQ,		0, 1, 0x06 },
55/* 4. */	{ BPF_RET,			0, 0, 68 },
56/* 5. */	{ BPF_RET,			0, 0, 0 }
57};
58/*
59 * the code herein is dervied from libpcap.
60 */
61static	u_char	*buf = NULL;
62static	u_int	bufsize = 32768, timeout = 1;
63
64
65int	ack_recv(ep)
66char	*ep;
67{
68	struct	tcpiphdr	tip;
69	tcphdr_t	*tcp;
70	ip_t	*ip;
71
72	ip = (ip_t *)&tip;
73	tcp = (tcphdr_t *)(ip + 1);
74	bcopy(ep + 14, (char *)ip, sizeof(*ip));
75	bcopy(ep + 14 + (ip->ip_hl << 2), (char *)tcp, sizeof(*tcp));
76	if (ip->ip_p != IPPROTO_TCP && ip->ip_p != IPPROTO_UDP)
77		return -1;
78	if (ip->ip_p & 0x1fff != 0)
79		return 0;
80	if (0 == detect(ip, tcp))
81		return 1;
82	return 0;
83}
84
85
86int	readloop(fd, port, dst)
87int 	fd, port;
88struct	in_addr dst;
89{
90	register u_char	*bp, *cp, *bufend;
91	register struct	bpf_hdr	*bh;
92	register int	cc;
93	time_t	in = time(NULL);
94	int	done = 0;
95
96	while ((cc = read(fd, buf, bufsize)) >= 0) {
97		if (!cc && (time(NULL) - in) > timeout)
98			return done;
99		bp = buf;
100		bufend = buf + cc;
101		/*
102		 * loop through each snapshot in the chunk
103		 */
104		while (bp < bufend) {
105			bh = (struct bpf_hdr *)bp;
106			cp = bp + bh->bh_hdrlen;
107			done += ack_recv(cp);
108			bp += BPF_WORDALIGN(bh->bh_caplen + bh->bh_hdrlen);
109		}
110		return done;
111	}
112	perror("read");
113	exit(-1);
114}
115
116int	initdevice(device, tout)
117char	*device;
118int	tout;
119{
120	struct	bpf_program prog;
121	struct	bpf_version bv;
122	struct	timeval to;
123	struct	ifreq ifr;
124	char	bpfname[16];
125	int	fd, i;
126
127	for (i = 0; i < 16; i++)
128	    {
129		(void) sprintf(bpfname, "/dev/bpf%d", i);
130		if ((fd = open(bpfname, O_RDWR)) >= 0)
131			break;
132	    }
133	if (i == 16)
134	    {
135		fprintf(stderr, "no bpf devices available as /dev/bpfxx\n");
136		return -1;
137	    }
138
139	if (ioctl(fd, BIOCVERSION, (caddr_t)&bv) < 0)
140	    {
141		perror("BIOCVERSION");
142		return -1;
143	    }
144	if (bv.bv_major != BPF_MAJOR_VERSION ||
145	    bv.bv_minor < BPF_MINOR_VERSION)
146	    {
147		fprintf(stderr, "kernel bpf (v%d.%d) filter out of date:\n",
148			bv.bv_major, bv.bv_minor);
149		fprintf(stderr, "current version: %d.%d\n",
150			BPF_MAJOR_VERSION, BPF_MINOR_VERSION);
151		return -1;
152	    }
153
154	(void) strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
155	if (ioctl(fd, BIOCSETIF, &ifr) == -1)
156	    {
157		fprintf(stderr, "%s(%d):", ifr.ifr_name, fd);
158		perror("BIOCSETIF");
159		exit(1);
160	    }
161	/*
162	 * set the timeout
163	 */
164	timeout = tout;
165	to.tv_sec = 1;
166	to.tv_usec = 0;
167	if (ioctl(fd, BIOCSRTIMEOUT, (caddr_t)&to) == -1)
168	    {
169		perror("BIOCSRTIMEOUT");
170		exit(-1);
171	    }
172	/*
173	 * get kernel buffer size
174	 */
175	if (ioctl(fd, BIOCSBLEN, &bufsize) == -1)
176		perror("BIOCSBLEN");
177	if (ioctl(fd, BIOCGBLEN, &bufsize) == -1)
178	    {
179		perror("BIOCGBLEN");
180		exit(-1);
181	    }
182	printf("BPF buffer size: %d\n", bufsize);
183	buf = (u_char*)malloc(bufsize);
184
185	prog.bf_len = sizeof(filter) / sizeof(struct bpf_insn);
186	prog.bf_insns = filter;
187	if (ioctl(fd, BIOCSETF, (caddr_t)&prog) == -1)
188	    {
189		perror("BIOCSETF");
190		exit(-1);
191	    }
192	(void) ioctl(fd, BIOCFLUSH, 0);
193	return fd;
194}
195