wireshark/packet.c

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/* packet.c
* Routines for packet disassembly
*
* $Id: packet.c,v 1.50 1999/10/15 20:32:57 guy Exp $
*
* Ethereal - Network traffic analyzer
* By Gerald Combs <gerald@zing.org>
* Copyright 1998 Gerald Combs
*
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#ifdef HAVE_SYS_TYPES_H
# include <sys/types.h>
#endif
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#ifdef HAVE_WINSOCK_H
#include <winsock.h>
#endif
#include <glib.h>
#include <stdio.h>
#include <stdarg.h>
#include <string.h>
#include <ctype.h>
#include <time.h>
#ifdef NEED_SNPRINTF_H
# include "snprintf.h"
#endif
#ifdef HAVE_NETINET_IN_H
# include <netinet/in.h>
#endif
#include <arpa/inet.h>
#ifdef NEED_INET_V6DEFS_H
# include "inet_v6defs.h"
#endif
#include "packet.h"
#include "print.h"
#include "file.h"
extern capture_file cf;
gboolean tree_is_expanded[NUM_TREE_TYPES];
int proto_frame = -1;
int hf_frame_arrival_time = -1;
int hf_frame_time_delta = -1;
int hf_frame_number = -1;
int hf_frame_packet_len = -1;
int hf_frame_capture_len = -1;
gchar *
ether_to_str(const guint8 *ad) {
static gchar str[3][18];
static gchar *cur;
gchar *p;
int i;
guint32 octet;
static const gchar hex_digits[16] = "0123456789abcdef";
if (cur == &str[0][0]) {
cur = &str[1][0];
} else if (cur == &str[1][0]) {
cur = &str[2][0];
} else {
cur = &str[0][0];
}
p = &cur[18];
*--p = '\0';
i = 5;
for (;;) {
octet = ad[i];
*--p = hex_digits[octet&0xF];
octet >>= 4;
*--p = hex_digits[octet&0xF];
if (i == 0)
break;
*--p = ':';
i--;
}
return p;
}
gchar *
ip_to_str(const guint8 *ad) {
static gchar str[3][16];
static gchar *cur;
gchar *p;
int i;
guint32 octet;
guint32 digit;
if (cur == &str[0][0]) {
cur = &str[1][0];
} else if (cur == &str[1][0]) {
cur = &str[2][0];
} else {
cur = &str[0][0];
}
p = &cur[16];
*--p = '\0';
i = 3;
for (;;) {
octet = ad[i];
*--p = (octet%10) + '0';
octet /= 10;
digit = octet%10;
octet /= 10;
if (digit != 0 || octet != 0)
*--p = digit + '0';
if (octet != 0)
*--p = octet + '0';
if (i == 0)
break;
*--p = '.';
i--;
}
return p;
}
gchar *
ip6_to_str(struct e_in6_addr *ad) {
#ifndef INET6_ADDRSTRLEN
#define INET6_ADDRSTRLEN 46
#endif
static gchar buf[INET6_ADDRSTRLEN];
inet_ntop(AF_INET6, (u_char*)ad, (gchar*)buf, sizeof(buf));
return buf;
}
#define PLURALIZE(n) (((n) > 1) ? "s" : "")
#define COMMA(do_it) ((do_it) ? ", " : "")
gchar *
time_secs_to_str(guint32 time)
{
static gchar str[3][8+1+4+2+2+5+2+2+7+2+2+7+1];
static gchar *cur, *p;
int hours, mins, secs;
int do_comma;
if (cur == &str[0][0]) {
cur = &str[1][0];
} else if (cur == &str[1][0]) {
cur = &str[2][0];
} else {
cur = &str[0][0];
}
secs = time % 60;
time /= 60;
mins = time % 60;
time /= 60;
hours = time % 24;
time /= 24;
p = cur;
if (time != 0) {
sprintf(p, "%u day%s", time, PLURALIZE(time));
p += strlen(p);
do_comma = 1;
} else
do_comma = 0;
if (hours != 0) {
sprintf(p, "%s%u hour%s", COMMA(do_comma), hours, PLURALIZE(hours));
p += strlen(p);
do_comma = 1;
} else
do_comma = 0;
if (mins != 0) {
sprintf(p, "%s%u minute%s", COMMA(do_comma), mins, PLURALIZE(mins));
p += strlen(p);
do_comma = 1;
} else
do_comma = 0;
if (secs != 0)
sprintf(p, "%s%u second%s", COMMA(do_comma), secs, PLURALIZE(secs));
return cur;
}
/* Max string length for displaying byte string. */
#define MAX_BYTE_STR_LEN 20
/* Turn an array of bytes into a string showing the bytes in hex. */
gchar *
bytes_to_str(const guint8 *bd, int bd_len) {
static gchar str[3][MAX_BYTE_STR_LEN+3+1];
static gchar *cur;
gchar *p;
int len;
static const char hex[16] = { '0', '1', '2', '3', '4', '5', '6', '7',
'8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
if (cur == &str[0][0]) {
cur = &str[1][0];
} else if (cur == &str[1][0]) {
cur = &str[2][0];
} else {
cur = &str[0][0];
}
p = cur;
len = MAX_BYTE_STR_LEN;
while (bd_len > 0 && len > 0) {
*p++ = hex[(*bd) >> 4];
*p++ = hex[(*bd) & 0xF];
len -= 2;
bd++;
bd_len--;
}
if (bd_len != 0) {
/* Note that we're not showing the full string. */
*p++ = '.';
*p++ = '.';
*p++ = '.';
}
*p = '\0';
return cur;
}
static const char *mon_names[12] = {
"Jan",
"Feb",
"Mar",
"Apr",
"May",
"Jun",
"Jul",
"Aug",
"Sep",
"Oct",
"Nov",
"Dec"
};
gchar *
abs_time_to_str(struct timeval *abs_time)
{
struct tm *tmp;
static gchar *cur;
static char str[3][3+1+2+2+4+1+2+1+2+1+2+1+4+1 + 5 /* extra */];
if (cur == &str[0][0]) {
cur = &str[1][0];
} else if (cur == &str[1][0]) {
cur = &str[2][0];
} else {
cur = &str[0][0];
}
tmp = localtime(&abs_time->tv_sec);
sprintf(cur, "%s %2d, %d %02d:%02d:%02d.%04ld",
mon_names[tmp->tm_mon],
tmp->tm_mday,
tmp->tm_year + 1900,
tmp->tm_hour,
tmp->tm_min,
tmp->tm_sec,
(long)abs_time->tv_usec/100);
return cur;
}
gchar *
rel_time_to_str(struct timeval *rel_time)
{
static gchar *cur;
static char str[3][10+1+6+1];
if (cur == &str[0][0]) {
cur = &str[1][0];
} else if (cur == &str[1][0]) {
cur = &str[2][0];
} else {
cur = &str[0][0];
}
sprintf(cur, "%ld.%06ld", (long)rel_time->tv_sec,
(long)rel_time->tv_usec);
return cur;
}
/*
* Given a pointer into a data buffer, and to the end of the buffer,
* find the end of the (putative) line at that position in the data
* buffer.
* Return a pointer to the EOL character(s) in "*eol".
*/
const u_char *
find_line_end(const u_char *data, const u_char *dataend, const u_char **eol)
{
const u_char *lineend;
lineend = memchr(data, '\n', dataend - data);
if (lineend == NULL) {
/*
* No LF - line is probably continued in next TCP segment.
*/
lineend = dataend;
*eol = dataend;
} else {
/*
* Is the LF at the beginning of the line?
*/
if (lineend > data) {
/*
* No - is it preceded by a carriage return?
* (Perhaps it's supposed to be, but that's not guaranteed....)
*/
if (*(lineend - 1) == '\r') {
/*
* Yes. The EOL starts with the CR.
*/
*eol = lineend - 1;
} else {
/*
* No. The EOL starts with the LF.
*/
*eol = lineend;
/*
* I seem to remember that we once saw lines ending with LF-CR
* in an HTTP request or response, so check if it's *followed*
* by a carriage return.
*/
if (lineend < (dataend - 1) && *(lineend + 1) == '\r') {
/*
* It's <non-LF><LF><CR>; say it ends with the CR.
*/
lineend++;
}
}
}
/*
* Point to the character after the last character.
*/
lineend++;
}
return lineend;
}
#define MAX_COLUMNS_LINE_DETAIL 62
/*
* Get the length of the next token in a line, and the beginning of the
* next token after that (if any).
* Return 0 if there is no next token.
*/
int
get_token_len(const u_char *linep, const u_char *lineend,
const u_char **next_token)
{
const u_char *tokenp;
int token_len;
tokenp = linep;
/*
* Search for a blank, a CR or an LF, or the end of the buffer.
*/
while (linep < lineend && *linep != ' ' && *linep != '\r' && *linep != '\n')
linep++;
token_len = linep - tokenp;
/*
* Skip trailing blanks.
*/
while (linep < lineend && *linep == ' ')
linep++;
*next_token = linep;
return token_len;
}
/*
* Given a string, generate a string from it that shows non-printable
* characters as C-style escapes, and return a pointer to it.
*/
gchar *
format_text(const u_char *string, int len)
{
static gchar fmtbuf[MAX_COLUMNS_LINE_DETAIL + 3 + 4 + 1];
gchar *fmtbufp;
int column;
const u_char *stringend = string + len;
u_char c;
int i;
column = 0;
fmtbufp = &fmtbuf[0];
while (string < stringend) {
if (column >= MAX_COLUMNS_LINE_DETAIL) {
/*
* Put "..." and quit.
*/
strcpy(fmtbufp, " ...");
break;
}
c = *string++;
if (isprint(c)) {
*fmtbufp++ = c;
column++;
} else {
*fmtbufp++ = '\\';
column++;
switch (c) {
case '\\':
*fmtbufp++ = '\\';
column++;
break;
case '\a':
*fmtbufp++ = 'a';
column++;
break;
case '\b':
*fmtbufp++ = 'b';
column++;
break;
case '\f':
*fmtbufp++ = 'f';
column++;
break;
case '\n':
*fmtbufp++ = 'n';
column++;
break;
case '\r':
*fmtbufp++ = 'r';
column++;
break;
case '\t':
*fmtbufp++ = 't';
column++;
break;
case '\v':
*fmtbufp++ = 'v';
column++;
break;
default:
i = (c>>6)&03;
*fmtbufp++ = i + '0';
column++;
i = (c>>3)&07;
*fmtbufp++ = i + '0';
column++;
i = (c>>0)&07;
*fmtbufp++ = i + '0';
column++;
break;
}
}
}
*fmtbufp = '\0';
return fmtbuf;
}
/* Tries to match val against each element in the value_string array vs.
Returns the associated string ptr on a match.
Formats val with fmt, and returns the resulting string, on failure. */
gchar*
val_to_str(guint32 val, const value_string *vs, const char *fmt) {
gchar *ret;
static gchar str[3][64];
static gchar *cur;
ret = match_strval(val, vs);
if (ret != NULL)
return ret;
if (cur == &str[0][0]) {
cur = &str[1][0];
} else if (cur == &str[1][0]) {
cur = &str[2][0];
} else {
cur = &str[0][0];
}
snprintf(cur, 64, fmt, val);
return cur;
}
/* Tries to match val against each element in the value_string array vs.
Returns the associated string ptr on a match, or NULL on failure. */
gchar*
match_strval(guint32 val, const value_string *vs) {
gint i = 0;
while (vs[i].strptr) {
if (vs[i].value == val)
return(vs[i].strptr);
i++;
}
return(NULL);
}
/* Generate, into "buf", a string showing the bits of a bitfield.
Return a pointer to the character after that string. */
char *
decode_bitfield_value(char *buf, guint32 val, guint32 mask, int width)
{
int i;
guint32 bit;
char *p;
i = 0;
p = buf;
bit = 1 << (width - 1);
for (;;) {
if (mask & bit) {
/* This bit is part of the field. Show its value. */
if (val & bit)
*p++ = '1';
else
*p++ = '0';
} else {
/* This bit is not part of the field. */
*p++ = '.';
}
bit >>= 1;
i++;
if (i >= width)
break;
if (i % 4 == 0)
*p++ = ' ';
}
strcpy(p, " = ");
p += 3;
return p;
}
/* Generate a string describing a Boolean bitfield (a one-bit field that
says something is either true of false). */
const char *
decode_boolean_bitfield(guint32 val, guint32 mask, int width,
const char *truedesc, const char *falsedesc)
{
static char buf[1025];
char *p;
p = decode_bitfield_value(buf, val, mask, width);
if (val & mask)
strcpy(p, truedesc);
else
strcpy(p, falsedesc);
return buf;
}
/* Generate a string describing an enumerated bitfield (an N-bit field
with various specific values having particular names). */
const char *
decode_enumerated_bitfield(guint32 val, guint32 mask, int width,
const value_string *tab, const char *fmt)
{
static char buf[1025];
char *p;
p = decode_bitfield_value(buf, val, mask, width);
sprintf(p, fmt, val_to_str(val & mask, tab, "Unknown"));
return buf;
}
/* Generate a string describing a numeric bitfield (an N-bit field whose
value is just a number). */
const char *
decode_numeric_bitfield(guint32 val, guint32 mask, int width,
const char *fmt)
{
static char buf[1025];
char *p;
int shift = 0;
/* Compute the number of bits we have to shift the bitfield right
to extract its value. */
while ((mask & (1<<shift)) == 0)
shift++;
p = decode_bitfield_value(buf, val, mask, width);
sprintf(p, fmt, (val & mask) >> shift);
return buf;
}
/* Checks to see if a particular packet information element is needed for
the packet list */
gint
check_col(frame_data *fd, gint el) {
int i;
if (fd->cinfo) {
for (i = 0; i < fd->cinfo->num_cols; i++) {
if (fd->cinfo->fmt_matx[i][el])
return TRUE;
}
}
return FALSE;
}
/* Adds a vararg list to a packet info string. */
void
col_add_fstr(frame_data *fd, gint el, gchar *format, ...) {
va_list ap;
int i;
va_start(ap, format);
for (i = 0; i < fd->cinfo->num_cols; i++) {
if (fd->cinfo->fmt_matx[i][el])
vsnprintf(fd->cinfo->col_data[i], COL_MAX_LEN, format, ap);
}
}
void
col_add_str(frame_data *fd, gint el, const gchar* str) {
int i;
size_t max_len;
for (i = 0; i < fd->cinfo->num_cols; i++) {
if (fd->cinfo->fmt_matx[i][el]) {
if (el == COL_INFO)
max_len = COL_MAX_INFO_LEN;
else
max_len = COL_MAX_LEN;
strncpy(fd->cinfo->col_data[i], str, max_len);
fd->cinfo->col_data[i][max_len - 1] = 0;
}
}
}
void
col_append_str(frame_data *fd, gint el, gchar* str) {
int i;
size_t len, max_len;
for (i = 0; i < fd->cinfo->num_cols; i++) {
if (fd->cinfo->fmt_matx[i][el]) {
len = strlen(fd->cinfo->col_data[i]);
if (el == COL_INFO)
max_len = COL_MAX_LEN;
else
max_len = COL_MAX_INFO_LEN;
strncat(fd->cinfo->col_data[i], str, max_len - len);
fd->cinfo->col_data[i][max_len - 1] = 0;
}
}
}
/* this routine checks the frame type from the cf structure */
void
dissect_packet(const u_char *pd, frame_data *fd, proto_tree *tree)
{
proto_tree *fh_tree;
proto_item *ti;
struct timeval tv;
/* Put in frame header information. */
if (tree) {
ti = proto_tree_add_item_format(tree, proto_frame, 0, fd->cap_len,
NULL, "Frame (%d on wire, %d captured)", fd->pkt_len, fd->cap_len);
fh_tree = proto_item_add_subtree(ti, ETT_FRAME);
tv.tv_sec = fd->abs_secs;
tv.tv_usec = fd->abs_usecs;
proto_tree_add_item(fh_tree, hf_frame_arrival_time,
0, 0, &tv);
tv.tv_sec = fd->del_secs;
tv.tv_usec = fd->del_usecs;
proto_tree_add_item(fh_tree, hf_frame_time_delta,
0, 0, &tv);
proto_tree_add_item(fh_tree, hf_frame_number,
0, 0, fd->num);
proto_tree_add_item_format(fh_tree, hf_frame_packet_len,
0, 0, fd->pkt_len, "Packet Length: %d byte%s", fd->pkt_len,
plurality(fd->pkt_len, "", "s"));
proto_tree_add_item_format(fh_tree, hf_frame_capture_len,
0, 0, fd->cap_len, "Capture Length: %d byte%s", fd->cap_len,
plurality(fd->cap_len, "", "s"));
}
/* Set the initial payload to the packet length, and the initial
captured payload to the capture length (other protocols may
reduce them if their headers say they're less). */
pi.len = fd->pkt_len;
pi.captured_len = fd->cap_len;
switch (fd->lnk_t) {
case WTAP_ENCAP_ETHERNET :
dissect_eth(pd, 0, fd, tree);
break;
case WTAP_ENCAP_FDDI :
dissect_fddi(pd, fd, tree, FALSE);
break;
case WTAP_ENCAP_FDDI_BITSWAPPED :
dissect_fddi(pd, fd, tree, TRUE);
break;
case WTAP_ENCAP_TR :
dissect_tr(pd, 0, fd, tree);
break;
DLT_NULL, from "libpcap", means different things on different platforms and in different capture files; throw in some heuristics to try to figure out whether the 4-byte header is: 1) PPP-over-HDLC (some version of ISDN4BSD?); 2) big-endian AF_ value (BSD on big-endian platforms); 3) little-endian AF_ value (BSD on little-endian platforms); 4) two octets of 0 followed by an Ethernet type (Linux, at least on little-endian platforms, as mutated by "libpcap"). Make a separate Wiretap encapsulation type, WTAP_ENCAP_NULL, corresponding to DLT_NULL. Have the PPP code dissect the frame if it's PPP-over-HDLC, and have "ethertype()" dissect the Ethernet type and the rest of the packet if it's a Linux-style header; dissect it ourselves only if it's an AF_ value. Have Wiretap impose a maximum packet size of 65535 bytes, so that it fails more gracefully when handed a corrupt "libpcap" capture file (other capture file formats with more than a 16-bit capture length field, if any, will have that check added later), and put that size in "wtap.h" and have Ethereal use it as its notion of a maximum packet size. Have Ethereal put up a "this file appears to be damaged or corrupt" message box if Wiretap returns a WTAP_ERR_BAD_RECORD error when opening or reading a capture file. Include loopback interfaces in the list of interfaces offered by the "Capture" dialog box, but put them at the end of the list so that it doesn't default to a loopback interface unless there are no other interfaces. Also, don't require that an interface in the list have an IP address associated with it, and only put one entry in the list for a given interface (SIOCGIFCONF returns one entry per interface *address*, not per *interface* - and even if you were to use only IP addresses, an interface could conceivably have more than one IP address). Exclusively use Wiretap encapsulation types internally, even when capturing; don't use DLT_ types. svn path=/trunk/; revision=540
1999-08-22 00:47:56 +00:00
case WTAP_ENCAP_NULL :
dissect_null(pd, fd, tree);
break;
case WTAP_ENCAP_PPP :
dissect_ppp(pd, fd, tree);
break;
case WTAP_ENCAP_LAPB :
dissect_lapb(pd, fd, tree);
break;
case WTAP_ENCAP_RAW_IP :
dissect_raw(pd, fd, tree);
break;
case WTAP_ENCAP_LINUX_ATM_CLIP :
dissect_clip(pd, fd, tree);
break;
case WTAP_ENCAP_ATM_SNIFFER :
dissect_atm(pd, fd, tree);
break;
case WTAP_ENCAP_ASCEND :
dissect_ascend(pd, fd, tree);
break;
}
}
void
proto_register_frame(void)
{
static hf_register_info hf[] = {
{ &hf_frame_arrival_time,
{ "Arrival Time", "frame.time", FT_ABSOLUTE_TIME, BASE_NONE, NULL, 0x0,
""}},
{ &hf_frame_time_delta,
{ "Time delta from previous packet", "frame.time_delta", FT_RELATIVE_TIME, BASE_NONE, NULL,
0x0,
"" }},
{ &hf_frame_number,
{ "Frame Number", "frame.number", FT_UINT32, BASE_DEC, NULL, 0x0,
"" }},
{ &hf_frame_packet_len,
{ "Total Frame Length", "frame.pkt_len", FT_UINT32, BASE_DEC, NULL, 0x0,
"" }},
{ &hf_frame_capture_len,
{ "Capture Frame Length", "frame.cap_len", FT_UINT32, BASE_DEC, NULL, 0x0,
"" }},
};
proto_frame = proto_register_protocol("Frame", "frame");
proto_register_field_array(proto_frame, hf, array_length(hf));
}