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/* $FreeBSD$ */
/*
* Copyright (C) 2012 by Darren Reed.
*
* See the IPFILTER.LICENCE file for details on licencing.
*
* $Id$
*/
#include "ipf.h"
#include "ipt.h"
#if !defined(lint)
static const char rcsid[] = "@(#)$Id$";
#endif
struct llc {
int lc_type;
int lc_sz; /* LLC header length */
int lc_to; /* LLC Type offset */
int lc_tl; /* LLC Type length */
};
/*
* While many of these maybe the same, some do have different header formats
* which make this useful.
*/
static struct llc llcs[] = {
{ 0, 0, 0, 0 }, /* DLT_NULL */
{ 1, 14, 12, 2 }, /* DLT_Ethernet */
{ 10, 0, 0, 0 }, /* DLT_FDDI */
{ 12, 0, 0, 0 }, /* DLT_RAW */
{ -1, -1, -1, -1 }
};
typedef struct {
u_int id;
u_short major;
u_short minor;
u_int timezone;
u_int sigfigs;
u_int snaplen;
u_int type;
} fileheader_t;
typedef struct {
u_32_t seconds;
u_32_t microseconds;
u_32_t caplen;
u_32_t wirelen;
} packetheader_t;
static int ipcap_open __P((char *));
static int ipcap_close __P((void));
static int ipcap_readip __P((mb_t *, char **, int *));
static int ipcap_read_rec __P((packetheader_t *));
static void iswap_hdr __P((fileheader_t *));
static int pfd = -1, swapped = 0;
static struct llc *llcp = NULL;
struct ipread pcap = { ipcap_open, ipcap_close, ipcap_readip, 0 };
#define SWAPLONG(y) \
((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff))
#define SWAPSHORT(y) \
( (((y)&0xff)<<8) | (((y)&0xff00)>>8) )
static void iswap_hdr(p)
fileheader_t *p;
{
p->major = SWAPSHORT(p->major);
p->minor = SWAPSHORT(p->minor);
p->timezone = SWAPLONG(p->timezone);
p->sigfigs = SWAPLONG(p->sigfigs);
p->snaplen = SWAPLONG(p->snaplen);
p->type = SWAPLONG(p->type);
}
static int ipcap_open(fname)
char *fname;
{
fileheader_t ph;
int fd, i;
if (pfd != -1)
return pfd;
if (!strcmp(fname, "-"))
fd = 0;
else if ((fd = open(fname, O_RDONLY)) == -1)
return -1;
if (read(fd, (char *)&ph, sizeof(ph)) != sizeof(ph))
return -2;
if (ph.id != 0xa1b2c3d4) {
if (SWAPLONG(ph.id) != 0xa1b2c3d4) {
(void) close(fd);
return -2;
}
swapped = 1;
iswap_hdr(&ph);
}
for (i = 0; llcs[i].lc_type != -1; i++)
if (llcs[i].lc_type == ph.type) {
llcp = llcs + i;
break;
}
if (llcp == NULL) {
(void) close(fd);
return -2;
}
pfd = fd;
printf("opened pcap file %s:\n", fname);
printf("\tid: %08x version: %d.%d type: %d snap %d\n",
ph.id, ph.major, ph.minor, ph.type, ph.snaplen);
return fd;
}
static int ipcap_close()
{
return close(pfd);
}
/*
* read in the header (and validate) which should be the first record
* in a pcap file.
*/
static int ipcap_read_rec(rec)
packetheader_t *rec;
{
int n, p, i;
char *s;
s = (char *)rec;
n = sizeof(*rec);
while (n > 0) {
i = read(pfd, (char *)rec, sizeof(*rec));
if (i <= 0)
return -2;
s += i;
n -= i;
}
if (swapped) {
rec->caplen = SWAPLONG(rec->caplen);
rec->wirelen = SWAPLONG(rec->wirelen);
rec->seconds = SWAPLONG(rec->seconds);
rec->microseconds = SWAPLONG(rec->microseconds);
}
p = rec->caplen;
n = MIN(p, rec->wirelen);
if (!n || n < 0)
return -3;
if (p < 0 || p > 65536)
return -4;
return p;
}
#ifdef notyet
/*
* read an entire pcap packet record. only the data part is copied into
* the available buffer, with the number of bytes copied returned.
*/
static int ipcap_read(buf, cnt)
char *buf;
int cnt;
{
packetheader_t rec;
static char *bufp = NULL;
int i, n;
if ((i = ipcap_read_rec(&rec)) <= 0)
return i;
if (!bufp)
bufp = malloc(i);
else
bufp = realloc(bufp, i);
if (read(pfd, bufp, i) != i)
return -2;
n = MIN(i, cnt);
bcopy(bufp, buf, n);
return n;
}
#endif
/*
* return only an IP packet read into buf
*/
static int ipcap_readip(mb, ifn, dir)
mb_t *mb;
char **ifn;
int *dir;
{
static char *bufp = NULL;
packetheader_t rec;
struct llc *l;
char *s, ty[4];
int i, j, n;
char *buf;
int cnt;
#if 0
ifn = ifn; /* gcc -Wextra */
dir = dir; /* gcc -Wextra */
#endif
buf = (char *)mb->mb_buf;
cnt = sizeof(mb->mb_buf);
l = llcp;
/* do { */
if ((i = ipcap_read_rec(&rec)) <= 0)
return i;
if (!bufp)
bufp = malloc(i);
else
bufp = realloc(bufp, i);
s = bufp;
for (j = i, n = 0; j > 0; ) {
n = read(pfd, s, j);
if (n <= 0)
return -2;
j -= n;
s += n;
}
s = bufp;
i -= l->lc_sz;
s += l->lc_to;
bcopy(s, ty, l->lc_tl);
s += l->lc_tl;
/* } while (ty[0] != 0x8 && ty[1] != 0); */
n = MIN(i, cnt);
bcopy(s, buf, n);
mb->mb_len = n;
return n;
}
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