1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
|
/*
* (C)opyright 1995-1998 Darren Reed. (from tcplog)
*
* See the IPFILTER.LICENCE file for details on licencing.
*
*/
#include <stdio.h>
#include <netdb.h>
#include <ctype.h>
#include <signal.h>
#include <errno.h>
#ifdef __NetBSD__
# include <paths.h>
#endif
#include <sys/types.h>
#include <sys/param.h>
#include <sys/mbuf.h>
#include <sys/time.h>
#include <sys/timeb.h>
#include <sys/socket.h>
#include <sys/file.h>
#include <sys/ioctl.h>
#if BSD < 199103
#include <sys/fcntlcom.h>
#endif
#include <sys/dir.h>
#include <net/bpf.h>
#include <net/if.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/if_ether.h>
#include <netinet/ip_var.h>
#include <netinet/udp.h>
#include <netinet/udp_var.h>
#include <netinet/tcp.h>
#include <netinet/tcpip.h>
#include "ip_compat.h"
#ifndef lint
static char sbpf[] = "@(#)sbpf.c 1.2 12/3/95 (C)1995 Darren Reed";
#endif
/*
(000) ldh [12]
(001) jeq #0x800 jt 2 jf 5
(002) ldb [23]
(003) jeq #0x6 jt 4 jf 5
(004) ret #68
(005) ret #0
*/
struct bpf_insn filter[] = {
/* 0. */ { BPF_LD|BPF_H|BPF_ABS, 0, 0, 12 },
/* 1. */ { BPF_JMP|BPF_JEQ, 0, 3, 0x0800 },
/* 2. */ { BPF_LD|BPF_B|BPF_ABS, 0, 0, 23 },
/* 3. */ { BPF_JMP|BPF_JEQ, 0, 1, 0x06 },
/* 4. */ { BPF_RET, 0, 0, 68 },
/* 5. */ { BPF_RET, 0, 0, 0 }
};
/*
* the code herein is dervied from libpcap.
*/
static u_char *buf = NULL;
static u_int bufsize = 32768, timeout = 1;
int ack_recv(ep)
char *ep;
{
struct tcpiphdr tip;
tcphdr_t *tcp;
ip_t *ip;
ip = (ip_t *)&tip;
tcp = (tcphdr_t *)(ip + 1);
bcopy(ep + 14, (char *)ip, sizeof(*ip));
bcopy(ep + 14 + (ip->ip_hl << 2), (char *)tcp, sizeof(*tcp));
if (ip->ip_p != IPPROTO_TCP && ip->ip_p != IPPROTO_UDP)
return -1;
if (ip->ip_p & 0x1fff != 0)
return 0;
if (0 == detect(ip, tcp))
return 1;
return 0;
}
int readloop(fd, port, dst)
int fd, port;
struct in_addr dst;
{
register u_char *bp, *cp, *bufend;
register struct bpf_hdr *bh;
register int cc;
time_t in = time(NULL);
int done = 0;
while ((cc = read(fd, buf, bufsize)) >= 0) {
if (!cc && (time(NULL) - in) > timeout)
return done;
bp = buf;
bufend = buf + cc;
/*
* loop through each snapshot in the chunk
*/
while (bp < bufend) {
bh = (struct bpf_hdr *)bp;
cp = bp + bh->bh_hdrlen;
done += ack_recv(cp);
bp += BPF_WORDALIGN(bh->bh_caplen + bh->bh_hdrlen);
}
return done;
}
perror("read");
exit(-1);
}
int initdevice(device, tout)
char *device;
int tout;
{
struct bpf_program prog;
struct bpf_version bv;
struct timeval to;
struct ifreq ifr;
#ifdef _PATH_BPF
char *bpfname = _PATH_BPF;
int fd;
if ((fd = open(bpfname, O_RDWR)) < 0)
{
fprintf(stderr, "no bpf devices available as /dev/bpfxx\n");
return -1;
}
#else
char bpfname[16];
int fd = -1, i;
for (i = 0; i < 16; i++)
{
(void) sprintf(bpfname, "/dev/bpf%d", i);
if ((fd = open(bpfname, O_RDWR)) >= 0)
break;
}
if (i == 16)
{
fprintf(stderr, "no bpf devices available as /dev/bpfxx\n");
return -1;
}
#endif
if (ioctl(fd, BIOCVERSION, (caddr_t)&bv) < 0)
{
perror("BIOCVERSION");
return -1;
}
if (bv.bv_major != BPF_MAJOR_VERSION ||
bv.bv_minor < BPF_MINOR_VERSION)
{
fprintf(stderr, "kernel bpf (v%d.%d) filter out of date:\n",
bv.bv_major, bv.bv_minor);
fprintf(stderr, "current version: %d.%d\n",
BPF_MAJOR_VERSION, BPF_MINOR_VERSION);
return -1;
}
(void) strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
if (ioctl(fd, BIOCSETIF, &ifr) == -1)
{
fprintf(stderr, "%s(%d):", ifr.ifr_name, fd);
perror("BIOCSETIF");
exit(1);
}
/*
* set the timeout
*/
timeout = tout;
to.tv_sec = 1;
to.tv_usec = 0;
if (ioctl(fd, BIOCSRTIMEOUT, (caddr_t)&to) == -1)
{
perror("BIOCSRTIMEOUT");
exit(-1);
}
/*
* get kernel buffer size
*/
if (ioctl(fd, BIOCSBLEN, &bufsize) == -1)
perror("BIOCSBLEN");
if (ioctl(fd, BIOCGBLEN, &bufsize) == -1)
{
perror("BIOCGBLEN");
exit(-1);
}
printf("BPF buffer size: %d\n", bufsize);
buf = (u_char*)malloc(bufsize);
prog.bf_len = sizeof(filter) / sizeof(struct bpf_insn);
prog.bf_insns = filter;
if (ioctl(fd, BIOCSETF, (caddr_t)&prog) == -1)
{
perror("BIOCSETF");
exit(-1);
}
(void) ioctl(fd, BIOCFLUSH, 0);
return fd;
}
|
