1 /* $NetBSD: sbpf.c,v 1.1.1.1 2012/03/23 21:20:06 christos Exp $ */
2
3 /*
4 * (C)opyright 1995-1998 Darren Reed. (from tcplog)
5 *
6 * See the IPFILTER.LICENCE file for details on licencing.
7 *
8 */
9 #include <stdio.h>
10 #include <netdb.h>
11 #include <ctype.h>
12 #include <signal.h>
13 #include <errno.h>
14 #ifdef __NetBSD__
15 # include <paths.h>
16 #endif
17 #include <sys/types.h>
18 #include <sys/param.h>
19 #include <sys/mbuf.h>
20 #include <sys/time.h>
21 #include <sys/timeb.h>
22 #include <sys/socket.h>
23 #include <sys/file.h>
24 #include <sys/ioctl.h>
25 #if BSD < 199103
26 #include <sys/fcntlcom.h>
27 #endif
28 #include <sys/dir.h>
29 #include <net/bpf.h>
30
31 #include <net/if.h>
32 #include <netinet/in.h>
33 #include <netinet/in_systm.h>
34 #include <netinet/ip.h>
35 #include <netinet/if_ether.h>
36 #include <netinet/ip_var.h>
37 #include <netinet/udp.h>
38 #include <netinet/udp_var.h>
39 #include <netinet/tcp.h>
40 #include <netinet/tcpip.h>
41 #include "ip_compat.h"
42
43 #ifndef lint
44 static char sbpf[] = "@(#)sbpf.c 1.2 12/3/95 (C)1995 Darren Reed";
45 #endif
46
47 /*
48 (000) ldh [12]
49 (001) jeq #0x800 jt 2 jf 5
50 (002) ldb [23]
51 (003) jeq #0x6 jt 4 jf 5
52 (004) ret #68
53 (005) ret #0
54 */
55 struct bpf_insn filter[] = {
56 /* 0. */ { BPF_LD|BPF_H|BPF_ABS, 0, 0, 12 },
57 /* 1. */ { BPF_JMP|BPF_JEQ, 0, 3, 0x0800 },
58 /* 2. */ { BPF_LD|BPF_B|BPF_ABS, 0, 0, 23 },
59 /* 3. */ { BPF_JMP|BPF_JEQ, 0, 1, 0x06 },
60 /* 4. */ { BPF_RET, 0, 0, 68 },
61 /* 5. */ { BPF_RET, 0, 0, 0 }
62 };
63 /*
64 * the code herein is dervied from libpcap.
65 */
66 static u_char *buf = NULL;
67 static u_int bufsize = 32768, timeout = 1;
68
69
ack_recv(ep)70 int ack_recv(ep)
71 char *ep;
72 {
73 struct tcpiphdr tip;
74 tcphdr_t *tcp;
75 ip_t *ip;
76
77 ip = (ip_t *)&tip;
78 tcp = (tcphdr_t *)(ip + 1);
79 bcopy(ep + 14, (char *)ip, sizeof(*ip));
80 bcopy(ep + 14 + (ip->ip_hl << 2), (char *)tcp, sizeof(*tcp));
81 if (ip->ip_p != IPPROTO_TCP && ip->ip_p != IPPROTO_UDP)
82 return -1;
83 if (ip->ip_p & 0x1fff != 0)
84 return 0;
85 if (0 == detect(ip, tcp))
86 return 1;
87 return 0;
88 }
89
90
readloop(fd,port,dst)91 int readloop(fd, port, dst)
92 int fd, port;
93 struct in_addr dst;
94 {
95 register u_char *bp, *cp, *bufend;
96 register struct bpf_hdr *bh;
97 register int cc;
98 time_t in = time(NULL);
99 int done = 0;
100
101 while ((cc = read(fd, buf, bufsize)) >= 0) {
102 if (!cc && (time(NULL) - in) > timeout)
103 return done;
104 bp = buf;
105 bufend = buf + cc;
106 /*
107 * loop through each snapshot in the chunk
108 */
109 while (bp < bufend) {
110 bh = (struct bpf_hdr *)bp;
111 cp = bp + bh->bh_hdrlen;
112 done += ack_recv(cp);
113 bp += BPF_WORDALIGN(bh->bh_caplen + bh->bh_hdrlen);
114 }
115 return done;
116 }
117 perror("read");
118 exit(-1);
119 }
120
initdevice(device,tout)121 int initdevice(device, tout)
122 char *device;
123 int tout;
124 {
125 struct bpf_program prog;
126 struct bpf_version bv;
127 struct timeval to;
128 struct ifreq ifr;
129 #ifdef _PATH_BPF
130 char *bpfname = _PATH_BPF;
131 int fd;
132
133 if ((fd = open(bpfname, O_RDWR)) < 0)
134 {
135 fprintf(stderr, "no bpf devices available as /dev/bpfxx\n");
136 return -1;
137 }
138 #else
139 char bpfname[16];
140 int fd = -1, i;
141
142 for (i = 0; i < 16; i++)
143 {
144 (void) sprintf(bpfname, "/dev/bpf%d", i);
145 if ((fd = open(bpfname, O_RDWR)) >= 0)
146 break;
147 }
148 if (i == 16)
149 {
150 fprintf(stderr, "no bpf devices available as /dev/bpfxx\n");
151 return -1;
152 }
153 #endif
154
155 if (ioctl(fd, BIOCVERSION, (caddr_t)&bv) < 0)
156 {
157 perror("BIOCVERSION");
158 return -1;
159 }
160 if (bv.bv_major != BPF_MAJOR_VERSION ||
161 bv.bv_minor < BPF_MINOR_VERSION)
162 {
163 fprintf(stderr, "kernel bpf (v%d.%d) filter out of date:\n",
164 bv.bv_major, bv.bv_minor);
165 fprintf(stderr, "current version: %d.%d\n",
166 BPF_MAJOR_VERSION, BPF_MINOR_VERSION);
167 return -1;
168 }
169
170 (void) strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
171 if (ioctl(fd, BIOCSETIF, &ifr) == -1)
172 {
173 fprintf(stderr, "%s(%d):", ifr.ifr_name, fd);
174 perror("BIOCSETIF");
175 exit(1);
176 }
177 /*
178 * set the timeout
179 */
180 timeout = tout;
181 to.tv_sec = 1;
182 to.tv_usec = 0;
183 if (ioctl(fd, BIOCSRTIMEOUT, (caddr_t)&to) == -1)
184 {
185 perror("BIOCSRTIMEOUT");
186 exit(-1);
187 }
188 /*
189 * get kernel buffer size
190 */
191 if (ioctl(fd, BIOCSBLEN, &bufsize) == -1)
192 perror("BIOCSBLEN");
193 if (ioctl(fd, BIOCGBLEN, &bufsize) == -1)
194 {
195 perror("BIOCGBLEN");
196 exit(-1);
197 }
198 printf("BPF buffer size: %d\n", bufsize);
199 buf = (u_char*)malloc(bufsize);
200
201 prog.bf_len = sizeof(filter) / sizeof(struct bpf_insn);
202 prog.bf_insns = filter;
203 if (ioctl(fd, BIOCSETF, (caddr_t)&prog) == -1)
204 {
205 perror("BIOCSETF");
206 exit(-1);
207 }
208 (void) ioctl(fd, BIOCFLUSH, 0);
209 return fd;
210 }
211