1 /* $NetBSD: ipft_pc.c,v 1.3 2018/02/04 08:19:42 mrg Exp $ */
2
3 /*
4 * Copyright (C) 2012 by Darren Reed.
5 *
6 * See the IPFILTER.LICENCE file for details on licencing.
7 *
8 * Id: ipft_pc.c,v 1.1.1.2 2012/07/22 13:44:39 darrenr Exp $
9 */
10 #include "ipf.h"
11 #include "ipt.h"
12
13 #if !defined(lint)
14 static __attribute__((__used__)) const char rcsid[] = "@(#)Id: ipft_pc.c,v 1.1.1.2 2012/07/22 13:44:39 darrenr Exp $";
15 #endif
16
17 struct llc {
18 int lc_type;
19 int lc_sz; /* LLC header length */
20 int lc_to; /* LLC Type offset */
21 int lc_tl; /* LLC Type length */
22 };
23
24 /*
25 * While many of these maybe the same, some do have different header formats
26 * which make this useful.
27 */
28
29 static struct llc llcs[] = {
30 { 0, 0, 0, 0 }, /* DLT_NULL */
31 { 1, 14, 12, 2 }, /* DLT_Ethernet */
32 { 10, 0, 0, 0 }, /* DLT_FDDI */
33 { 12, 0, 0, 0 }, /* DLT_RAW */
34 { -1, -1, -1, -1 }
35 };
36
37 typedef struct {
38 u_int id;
39 u_short major;
40 u_short minor;
41 u_int timezone;
42 u_int sigfigs;
43 u_int snaplen;
44 u_int type;
45 } fileheader_t;
46
47 typedef struct {
48 u_32_t seconds;
49 u_32_t microseconds;
50 u_32_t caplen;
51 u_32_t wirelen;
52 } packetheader_t;
53
54 static int ipcap_open __P((char *));
55 static int ipcap_close __P((void));
56 static int ipcap_readip __P((mb_t *, char **, int *));
57 static int ipcap_read_rec __P((packetheader_t *));
58 static void iswap_hdr __P((fileheader_t *));
59
60 static int pfd = -1, swapped = 0;
61 static struct llc *llcp = NULL;
62
63 struct ipread pcap = { ipcap_open, ipcap_close, ipcap_readip, 0 };
64
65 #define SWAPLONG(y) \
66 ((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff))
67 #define SWAPSHORT(y) \
68 ( (((y)&0xff)<<8) | (((y)&0xff00)>>8) )
69
iswap_hdr(p)70 static void iswap_hdr(p)
71 fileheader_t *p;
72 {
73 p->major = SWAPSHORT(p->major);
74 p->minor = SWAPSHORT(p->minor);
75 p->timezone = SWAPLONG(p->timezone);
76 p->sigfigs = SWAPLONG(p->sigfigs);
77 p->snaplen = SWAPLONG(p->snaplen);
78 p->type = SWAPLONG(p->type);
79 }
80
ipcap_open(fname)81 static int ipcap_open(fname)
82 char *fname;
83 {
84 fileheader_t ph;
85 int fd, i;
86
87 if (pfd != -1)
88 return pfd;
89
90 if (!strcmp(fname, "-"))
91 fd = 0;
92 else if ((fd = open(fname, O_RDONLY)) == -1)
93 return -1;
94
95 if (read(fd, (char *)&ph, sizeof(ph)) != sizeof(ph))
96 return -2;
97
98 if (ph.id != 0xa1b2c3d4) {
99 if (SWAPLONG(ph.id) != 0xa1b2c3d4) {
100 (void) close(fd);
101 return -2;
102 }
103 swapped = 1;
104 iswap_hdr(&ph);
105 }
106
107 for (i = 0; llcs[i].lc_type != -1; i++)
108 if (llcs[i].lc_type == ph.type) {
109 llcp = llcs + i;
110 break;
111 }
112
113 if (llcp == NULL) {
114 (void) close(fd);
115 return -2;
116 }
117
118 pfd = fd;
119 printf("opened pcap file %s:\n", fname);
120 printf("\tid: %08x version: %d.%d type: %d snap %d\n",
121 ph.id, ph.major, ph.minor, ph.type, ph.snaplen);
122
123 return fd;
124 }
125
126
ipcap_close()127 static int ipcap_close()
128 {
129 return close(pfd);
130 }
131
132
133 /*
134 * read in the header (and validate) which should be the first record
135 * in a pcap file.
136 */
ipcap_read_rec(rec)137 static int ipcap_read_rec(rec)
138 packetheader_t *rec;
139 {
140 int n, p, i;
141 char *s;
142
143 s = (char *)rec;
144 n = sizeof(*rec);
145
146 while (n > 0) {
147 i = read(pfd, (char *)rec, sizeof(*rec));
148 if (i <= 0)
149 return -2;
150 s += i;
151 n -= i;
152 }
153
154 if (swapped) {
155 rec->caplen = SWAPLONG(rec->caplen);
156 rec->wirelen = SWAPLONG(rec->wirelen);
157 rec->seconds = SWAPLONG(rec->seconds);
158 rec->microseconds = SWAPLONG(rec->microseconds);
159 }
160 p = rec->caplen;
161 n = MIN(p, rec->wirelen);
162 if (!n || n < 0)
163 return -3;
164
165 if (p < 0 || p > 65536)
166 return -4;
167 return p;
168 }
169
170
171 #ifdef notyet
172 /*
173 * read an entire pcap packet record. only the data part is copied into
174 * the available buffer, with the number of bytes copied returned.
175 */
ipcap_read(buf,cnt)176 static int ipcap_read(buf, cnt)
177 char *buf;
178 int cnt;
179 {
180 packetheader_t rec;
181 static char *bufp = NULL;
182 int i, n;
183
184 if ((i = ipcap_read_rec(&rec)) <= 0)
185 return i;
186
187 if (!bufp)
188 bufp = malloc(i);
189 else
190 bufp = realloc(bufp, i);
191
192 if (read(pfd, bufp, i) != i)
193 return -2;
194
195 n = MIN(i, cnt);
196 bcopy(bufp, buf, n);
197 return n;
198 }
199 #endif
200
201
202 /*
203 * return only an IP packet read into buf
204 */
ipcap_readip(mb,ifn,dir)205 static int ipcap_readip(mb, ifn, dir)
206 mb_t *mb;
207 char **ifn;
208 int *dir;
209 {
210 static char *bufp = NULL;
211 packetheader_t rec;
212 struct llc *l;
213 char *s, ty[4];
214 int i, j, n;
215 char *buf;
216 int cnt;
217
218 ifn = ifn; /* gcc -Wextra */
219 dir = dir; /* gcc -Wextra */
220 buf = (char *)mb->mb_buf;
221 cnt = sizeof(mb->mb_buf);
222 l = llcp;
223
224 /* do { */
225 if ((i = ipcap_read_rec(&rec)) <= 0)
226 return i;
227
228 if (!bufp)
229 bufp = malloc(i);
230 else
231 bufp = realloc(bufp, i);
232 s = bufp;
233
234 for (j = i, n = 0; j > 0; ) {
235 n = read(pfd, s, j);
236 if (n <= 0)
237 return -2;
238 j -= n;
239 s += n;
240 }
241 s = bufp;
242
243 i -= l->lc_sz;
244 s += l->lc_to;
245 bcopy(s, ty, l->lc_tl);
246 s += l->lc_tl;
247 /* } while (ty[0] != 0x8 && ty[1] != 0); */
248 n = MIN(i, cnt);
249 bcopy(s, buf, n);
250 mb->mb_len = n;
251 return n;
252 }
253