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editcap.c
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/* editcap.c
* Edit capture files. We can delete packets, adjust timestamps, or
* simply convert from one format to another format.
*
* Originally written by Richard Sharpe.
* Improved by Guy Harris.
* Further improved by Richard Sharpe.
*
* Copyright 2013, Richard Sharpe <realrichardsharpe[AT]gmail.com>
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <[email protected]>
* Copyright 1998 Gerald Combs
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#include <config.h>
#define WS_LOG_DOMAIN LOG_DOMAIN_MAIN
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <math.h>
#include <stddef.h>
#include <time.h>
#include <glib.h>
#include <gcrypt.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <ws_exit_codes.h>
#include <wsutil/ws_getopt.h>
#include <wiretap/secrets-types.h>
#include <wiretap/wtap.h>
#include "epan/etypes.h"
#include "epan/dissectors/packet-ieee80211-radiotap-defs.h"
#ifdef _WIN32
#include <process.h> /* getpid */
#include <winsock2.h>
#endif
#include <wsutil/clopts_common.h>
#include <wsutil/cmdarg_err.h>
#include <wsutil/filesystem.h>
#include <wsutil/file_util.h>
#include <wsutil/plugins.h>
#include <wsutil/privileges.h>
#include <wsutil/strnatcmp.h>
#include <wsutil/str_util.h>
#include <cli_main.h>
#include <wsutil/version_info.h>
#include <wsutil/pint.h>
#include <wsutil/strtoi.h>
#include <wsutil/ws_assert.h>
#include <wsutil/wslog.h>
#include <wiretap/wtap_opttypes.h>
#include "ui/failure_message.h"
#include "ringbuffer.h" /* For RINGBUFFER_MAX_NUM_FILES */
/* Additional exit codes */
#define CANT_EXTRACT_PREFIX 2
#define WRITE_ERROR 2
#define DUMP_ERROR 2
#define NANOSECS_PER_SEC 1000000000
/*
* Some globals so we can pass things to various routines
*/
struct select_item {
bool inclusive;
uint64_t first, second;
};
/*
* Duplicate frame detection
*/
typedef struct _fd_hash_t {
uint8_t digest[16];
uint32_t len;
nstime_t frame_time;
} fd_hash_t;
#define DEFAULT_DUP_DEPTH 5 /* Used with -d */
#define MAX_DUP_DEPTH 1000000 /* the maximum window (and actual size of fd_hash[]) for de-duplication */
static fd_hash_t fd_hash[MAX_DUP_DEPTH];
static int dup_window = DEFAULT_DUP_DEPTH;
static int cur_dup_entry;
static uint32_t ignored_bytes; /* Used with -I */
#define ONE_BILLION 1000000000
/* Weights of different errors we can introduce */
/* We should probably make these command-line arguments */
/* XXX - Should we add a bit-level error? */
#define ERR_WT_BIT 5 /* Flip a random bit */
#define ERR_WT_BYTE 5 /* Substitute a random byte */
#define ERR_WT_ALNUM 5 /* Substitute a random character in [A-Za-z0-9] */
#define ERR_WT_FMT 2 /* Substitute "%s" */
#define ERR_WT_AA 1 /* Fill the remainder of the buffer with 0xAA */
#define ERR_WT_TOTAL (ERR_WT_BIT + ERR_WT_BYTE + ERR_WT_ALNUM + ERR_WT_FMT + ERR_WT_AA)
#define ALNUM_CHARS "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
#define ALNUM_LEN (sizeof(ALNUM_CHARS) - 1)
struct time_adjustment {
nstime_t tv;
int is_negative;
};
typedef struct _chop_t {
int len_begin;
int off_begin_pos;
int off_begin_neg;
int len_end;
int off_end_pos;
int off_end_neg;
} chop_t;
/* Table of user comments */
GTree *frames_user_comments;
GPtrArray *capture_comments;
#define MAX_SELECTIONS 512
static struct select_item selectfrm[MAX_SELECTIONS];
static unsigned max_selected;
static bool keep_em;
static int out_file_type_subtype = WTAP_FILE_TYPE_SUBTYPE_UNKNOWN;
static int out_frame_type = -2; /* Leave frame type alone */
static bool verbose; /* Not so verbose */
static struct time_adjustment time_adj; /* no adjustment */
static nstime_t relative_time_window; /* de-dup time window */
static double err_prob = -1.0;
static nstime_t starttime;
static bool have_starttime;
static nstime_t stoptime;
static bool have_stoptime;
static bool check_startstop;
static bool rem_vlan;
static bool dup_detect;
static bool dup_detect_by_time;
static bool skip_radiotap;
static bool discard_all_secrets;
static bool discard_cap_comments;
static bool set_unused;
static bool discard_pkt_comments;
static bool do_extract_secrets;
static int do_strict_time_adjustment;
static struct time_adjustment strict_time_adj; /* strict time adjustment */
static nstime_t previous_time; /* previous time */
static const struct {
const char *str;
uint32_t id;
} secrets_types[] = {
{ "tls", SECRETS_TYPE_TLS },
{ "ssh", SECRETS_TYPE_SSH },
{ "wg", SECRETS_TYPE_WIREGUARD },
{ "opcua", SECRETS_TYPE_OPCUA },
};
static unsigned find_dct2000_real_data(const uint8_t *buf);
static void handle_chopping(chop_t chop, wtap_packet_header *phdr,
uint8_t **buf, bool adjlen);
static char *
abs_time_to_str_with_sec_resolution(const nstime_t *abs_time)
{
struct tm *tmp;
char *buf = (char *)g_malloc(16);
tmp = localtime(&abs_time->secs);
if (tmp) {
snprintf(buf, 16, "%d%02d%02d%02d%02d%02d",
tmp->tm_year + 1900,
tmp->tm_mon+1,
tmp->tm_mday,
tmp->tm_hour,
tmp->tm_min,
tmp->tm_sec);
} else {
buf[0] = '\0';
}
return buf;
}
static char *
fileset_get_filename_by_pattern(unsigned idx, const nstime_t *ts,
char *fprefix, char *fsuffix)
{
char filenum[5+1];
char *timestr;
char *abs_str;
snprintf(filenum, sizeof(filenum), "%05u", idx % RINGBUFFER_MAX_NUM_FILES);
if (ts) {
timestr = abs_time_to_str_with_sec_resolution(ts);
abs_str = g_strconcat(fprefix, "_", filenum, "_", timestr, fsuffix, NULL);
g_free(timestr);
} else
abs_str = g_strconcat(fprefix, "_", filenum, fsuffix, NULL);
return abs_str;
}
static bool
fileset_extract_prefix_suffix(const char *fname, char **fprefix, char **fsuffix, wtap_compression_type *compression_typep)
{
char *pfx, *last_pathsep;
char *save_file;
wtap_compression_type compression_type;
save_file = g_strdup(fname);
if (save_file == NULL) {
fprintf(stderr, "editcap: Out of memory\n");
return false;
}
last_pathsep = strrchr(save_file, G_DIR_SEPARATOR);
if (last_pathsep == NULL) {
last_pathsep = save_file;
}
pfx = strrchr(last_pathsep, '.');
if (pfx != NULL) {
/* The pathname has a "." in it, and it's in the last component
* of the pathname (because there is either only one component,
* i.e. last_pathsep is null as there are no path separators,
* or the "." is after the path separator before the last
* component.
* Treat it as a separator between the rest of the file name and
* the file name suffix, and arrange that the names given to the
* ring buffer files have the specified suffix, i.e. put the
* changing part of the name *before* the suffix. */
pfx[0] = '\0';
compression_type = wtap_extension_to_compression_type(pfx + 1);
if (compression_type != WTAP_UNKNOWN_COMPRESSION) {
char *pfx2 = strrchr(last_pathsep, '.');
if (pfx2 != NULL) {
pfx[0] = '.';
pfx = pfx2;
pfx[0] = '\0';
}
if (compression_typep && *compression_typep == WTAP_UNKNOWN_COMPRESSION) {
*compression_typep = compression_type;
}
/* XXX - What if there's an extension matching a compression type
* and the passed in compression type is known but something else?
*/
}
*fprefix = g_strdup(save_file);
pfx[0] = '.'; /* restore capfile_name */
*fsuffix = g_strdup(pfx);
} else {
/* Either there's no "." in the pathname, or it's in a directory
* component, so the last component has no suffix. */
*fprefix = g_strdup(save_file);
*fsuffix = NULL;
}
g_free(save_file);
return true;
}
/* Add a selection item, a simple parser for now */
static bool
add_selection(char *sel, uint64_t* max_selection)
{
char *locn;
char *next;
if (max_selected >= MAX_SELECTIONS) {
/* Let the user know we stopped selecting */
fprintf(stderr, "Out of room for packet selections.\n");
return false;
}
if (verbose)
fprintf(stderr, "Add_Selected: %s\n", sel);
if ((locn = strchr(sel, '-')) == NULL) { /* No dash, so a single number? */
if (verbose)
fprintf(stderr, "Not inclusive ...");
selectfrm[max_selected].inclusive = false;
selectfrm[max_selected].first = get_uint64(sel, "packet number");
if (selectfrm[max_selected].first > *max_selection)
*max_selection = selectfrm[max_selected].first;
if (verbose)
fprintf(stderr, " %" PRIu64 "\n", selectfrm[max_selected].first);
} else {
if (verbose)
fprintf(stderr, "Inclusive ...");
*locn = '\0'; /* split the range */
next = locn + 1;
selectfrm[max_selected].inclusive = true;
selectfrm[max_selected].first = get_uint64(sel, "beginning of packet range");
selectfrm[max_selected].second = get_uint64(next, "end of packet range");
if (selectfrm[max_selected].second == 0)
{
/* Not a valid number, presume all */
selectfrm[max_selected].second = *max_selection = UINT64_MAX;
}
else if (selectfrm[max_selected].second > *max_selection)
*max_selection = selectfrm[max_selected].second;
if (verbose)
fprintf(stderr, " %" PRIu64 ", %" PRIu64 "\n", selectfrm[max_selected].first,
selectfrm[max_selected].second);
}
max_selected++;
return true;
}
/* Was the packet selected? */
static bool
selected(uint64_t recno)
{
unsigned i;
for (i = 0; i < max_selected; i++) {
if (selectfrm[i].inclusive) {
if (selectfrm[i].first <= recno && selectfrm[i].second >= recno)
return true;
} else {
if (recno == selectfrm[i].first)
return true;
}
}
return false;
}
static bool
set_time_adjustment(char *optarg_str_p)
{
char *frac, *end;
long val;
size_t frac_digits;
if (!optarg_str_p)
return true;
/* skip leading whitespace */
while (*optarg_str_p == ' ' || *optarg_str_p == '\t')
optarg_str_p++;
/* check for a negative adjustment */
if (*optarg_str_p == '-') {
time_adj.is_negative = 1;
optarg_str_p++;
}
/* collect whole number of seconds, if any */
if (*optarg_str_p == '.') { /* only fractional (i.e., .5 is ok) */
val = 0;
frac = optarg_str_p;
} else {
val = strtol(optarg_str_p, &frac, 10);
if (frac == NULL || frac == optarg_str_p
|| val == LONG_MIN || val == LONG_MAX) {
fprintf(stderr, "editcap: \"%s\" isn't a valid time adjustment\n",
optarg_str_p);
return false;
}
if (val < 0) { /* implies '--' since we caught '-' above */
fprintf(stderr, "editcap: \"%s\" isn't a valid time adjustment\n",
optarg_str_p);
return false;
}
}
time_adj.tv.secs = val;
/* now collect the partial seconds, if any */
if (*frac != '\0') { /* chars left, so get fractional part */
val = strtol(&(frac[1]), &end, 10);
/* if more than 9 fractional digits truncate to 9 */
if ((end - &(frac[1])) > 9) {
frac[10] = 't'; /* 't' for truncate */
val = strtol(&(frac[1]), &end, 10);
}
if (*frac != '.' || end == NULL || end == frac || val < 0
|| val >= ONE_BILLION || val == LONG_MIN || val == LONG_MAX) {
fprintf(stderr, "editcap: \"%s\" isn't a valid time adjustment\n",
optarg_str_p);
return false;
}
} else {
return true; /* no fractional digits */
}
/* adjust fractional portion from fractional to numerator
* e.g., in "1.5" from 5 to 500000000 since .5*10^9 = 500000000 */
frac_digits = end - frac - 1; /* fractional digit count (remember '.') */
while(frac_digits < 9) { /* this is frac of 10^9 */
val *= 10;
frac_digits++;
}
time_adj.tv.nsecs = (int)val;
return true;
}
static bool
set_strict_time_adj(char *optarg_str_p)
{
char *frac, *end;
long val;
size_t frac_digits;
if (!optarg_str_p)
return true;
/* skip leading whitespace */
while (*optarg_str_p == ' ' || *optarg_str_p == '\t')
optarg_str_p++;
/*
* check for a negative adjustment
* A negative strict adjustment value is a flag
* to adjust all frames by the specified delta time.
*/
if (*optarg_str_p == '-') {
strict_time_adj.is_negative = 1;
optarg_str_p++;
}
/* collect whole number of seconds, if any */
if (*optarg_str_p == '.') { /* only fractional (i.e., .5 is ok) */
val = 0;
frac = optarg_str_p;
} else {
val = strtol(optarg_str_p, &frac, 10);
if (frac == NULL || frac == optarg_str_p
|| val == LONG_MIN || val == LONG_MAX) {
fprintf(stderr, "editcap: \"%s\" isn't a valid time adjustment\n",
optarg_str_p);
return false;
}
if (val < 0) { /* implies '--' since we caught '-' above */
fprintf(stderr, "editcap: \"%s\" isn't a valid time adjustment\n",
optarg_str_p);
return false;
}
}
strict_time_adj.tv.secs = val;
/* now collect the partial seconds, if any */
if (*frac != '\0') { /* chars left, so get fractional part */
val = strtol(&(frac[1]), &end, 10);
/* if more than 9 fractional digits truncate to 9 */
if ((end - &(frac[1])) > 9) {
frac[10] = 't'; /* 't' for truncate */
val = strtol(&(frac[1]), &end, 10);
}
if (*frac != '.' || end == NULL || end == frac || val < 0
|| val >= ONE_BILLION || val == LONG_MIN || val == LONG_MAX) {
fprintf(stderr, "editcap: \"%s\" isn't a valid time adjustment\n",
optarg_str_p);
return false;
}
} else {
return true; /* no fractional digits */
}
/* adjust fractional portion from fractional to numerator
* e.g., in "1.5" from 5 to 500000000 since .5*10^9 = 500000000 */
frac_digits = end - frac - 1; /* fractional digit count (remember '.') */
while(frac_digits < 9) { /* this is frac of 10^9 */
val *= 10;
frac_digits++;
}
strict_time_adj.tv.nsecs = (int)val;
return true;
}
static bool
set_rel_time(char *optarg_str_p)
{
char *frac, *end;
long val;
size_t frac_digits;
if (!optarg_str_p)
return true;
/* skip leading whitespace */
while (*optarg_str_p == ' ' || *optarg_str_p == '\t')
optarg_str_p++;
/* ignore negative adjustment */
if (*optarg_str_p == '-')
optarg_str_p++;
/* collect whole number of seconds, if any */
if (*optarg_str_p == '.') { /* only fractional (i.e., .5 is ok) */
val = 0;
frac = optarg_str_p;
} else {
val = strtol(optarg_str_p, &frac, 10);
if (frac == NULL || frac == optarg_str_p
|| val == LONG_MIN || val == LONG_MAX) {
fprintf(stderr, "1: editcap: \"%s\" isn't a valid rel time value\n",
optarg_str_p);
return false;
}
if (val < 0) { /* implies '--' since we caught '-' above */
fprintf(stderr, "2: editcap: \"%s\" isn't a valid rel time value\n",
optarg_str_p);
return false;
}
}
relative_time_window.secs = val;
/* now collect the partial seconds, if any */
if (*frac != '\0') { /* chars left, so get fractional part */
val = strtol(&(frac[1]), &end, 10);
/* if more than 9 fractional digits truncate to 9 */
if ((end - &(frac[1])) > 9) {
frac[10] = 't'; /* 't' for truncate */
val = strtol(&(frac[1]), &end, 10);
}
if (*frac != '.' || end == NULL || end == frac || val < 0
|| val >= ONE_BILLION || val == LONG_MIN || val == LONG_MAX) {
fprintf(stderr, "3: editcap: \"%s\" isn't a valid rel time value\n",
optarg_str_p);
return false;
}
} else {
return true; /* no fractional digits */
}
/* adjust fractional portion from fractional to numerator
* e.g., in "1.5" from 5 to 500000000 since .5*10^9 = 500000000 */
frac_digits = end - frac - 1; /* fractional digit count (remember '.') */
while(frac_digits < 9) { /* this is frac of 10^9 */
val *= 10;
frac_digits++;
}
relative_time_window.nsecs = (int)val;
return true;
}
#define SLL_ADDRLEN 8 /* length of address field */
struct sll_header {
uint16_t sll_pkttype; /* packet type */
uint16_t sll_hatype; /* link-layer address type */
uint16_t sll_halen; /* link-layer address length */
uint8_t sll_addr[SLL_ADDRLEN]; /* link-layer address */
uint16_t sll_protocol; /* protocol */
};
struct sll2_header {
uint16_t sll2_protocol; /* protocol */
uint16_t sll2_reserved_mbz; /* reserved - must be zero */
uint32_t sll2_if_index; /* 1-based interface index */
uint16_t sll2_hatype; /* link-layer address type */
uint8_t sll2_pkttype; /* packet type */
uint8_t sll2_halen; /* link-layer address length */
uint8_t sll2_addr[SLL_ADDRLEN]; /* link-layer address */
};
#define VLAN_SIZE 4
static void
sll_remove_vlan_info(uint8_t* fd, uint32_t* len) {
if (pntoh16(fd + offsetof(struct sll_header, sll_protocol)) == ETHERTYPE_VLAN) {
int rest_len;
/* point to start of vlan */
fd = fd + offsetof(struct sll_header, sll_protocol);
/* bytes to read after vlan info */
rest_len = *len - (offsetof(struct sll_header, sll_protocol) + VLAN_SIZE);
/* remove vlan info from packet */
memmove(fd, fd + VLAN_SIZE, rest_len);
*len -= 4;
}
}
static void
sll_set_unused_info(uint8_t* fd) {
uint32_t ha_len;
ha_len = pntoh16(fd + offsetof(struct sll_header, sll_halen));
if (ha_len < SLL_ADDRLEN) {
int unused;
unused = SLL_ADDRLEN - ha_len;
/* point to end of sll_ddr */
fd = fd + offsetof(struct sll_header, sll_addr) + ha_len;
/* set zeros in the unused data */
memset(fd, 0, unused);
}
}
static void
sll2_set_unused_info(uint8_t* fd) {
uint32_t ha_len;
ha_len = *(fd + offsetof(struct sll2_header, sll2_halen));
if (ha_len < SLL_ADDRLEN) {
int unused;
unused = SLL_ADDRLEN - ha_len;
/* point to end of sll2_addr */
fd = fd + offsetof(struct sll2_header, sll2_addr) + ha_len;
/* set zeros in the unused data */
memset(fd, 0, unused);
}
}
static void
remove_vlan_info(wtap_packet_header *phdr, uint8_t* fd) {
switch (phdr->pkt_encap) {
case WTAP_ENCAP_SLL:
sll_remove_vlan_info(fd, &phdr->caplen);
break;
default:
/* no support for current pkt_encap */
break;
}
}
static void
set_unused_info(const wtap_packet_header *phdr, uint8_t* fd) {
switch (phdr->pkt_encap) {
case WTAP_ENCAP_SLL:
sll_set_unused_info(fd);
break;
case WTAP_ENCAP_SLL2:
sll2_set_unused_info(fd);
break;
default:
/* no support for current pkt_encap */
break;
}
}
static bool
is_duplicate(uint8_t* fd, uint32_t len) {
int i;
const struct ieee80211_radiotap_header* tap_header;
/*Hint to ignore some bytes at the start of the frame for the digest calculation(-I option) */
uint32_t offset = ignored_bytes;
uint32_t new_len;
uint8_t *new_fd;
if (len <= ignored_bytes) {
offset = 0;
}
/* Get the size of radiotap header and use that as offset (-p option) */
if (skip_radiotap == true) {
tap_header = (const struct ieee80211_radiotap_header*)fd;
offset = pletoh16(&tap_header->it_len);
if (offset >= len)
offset = 0;
}
new_fd = &fd[offset];
new_len = len - (offset);
cur_dup_entry++;
if (cur_dup_entry >= dup_window)
cur_dup_entry = 0;
/* Calculate our digest */
gcry_md_hash_buffer(GCRY_MD_MD5, fd_hash[cur_dup_entry].digest, new_fd, new_len);
fd_hash[cur_dup_entry].len = len;
/* Look for duplicates */
for (i = 0; i < dup_window; i++) {
if (i == cur_dup_entry)
continue;
if (fd_hash[i].len == fd_hash[cur_dup_entry].len
&& memcmp(fd_hash[i].digest, fd_hash[cur_dup_entry].digest, 16) == 0) {
return true;
}
}
return false;
}
static bool
is_duplicate_rel_time(uint8_t* fd, uint32_t len, const nstime_t *current) {
int i;
/*Hint to ignore some bytes at the start of the frame for the digest calculation(-I option) */
uint32_t offset = ignored_bytes;
uint32_t new_len;
uint8_t *new_fd;
if (len <= ignored_bytes) {
offset = 0;
}
new_fd = &fd[offset];
new_len = len - (offset);
cur_dup_entry++;
if (cur_dup_entry >= dup_window)
cur_dup_entry = 0;
/* Calculate our digest */
gcry_md_hash_buffer(GCRY_MD_MD5, fd_hash[cur_dup_entry].digest, new_fd, new_len);
fd_hash[cur_dup_entry].len = len;
fd_hash[cur_dup_entry].frame_time.secs = current->secs;
fd_hash[cur_dup_entry].frame_time.nsecs = current->nsecs;
/*
* Look for relative time related duplicates.
* This is hopefully a reasonably efficient mechanism for
* finding duplicates by rel time in the fd_hash[] cache.
* We check starting from the most recently added hash
* entries and work backwards towards older packets.
* This approach allows the dup test to be terminated
* when the relative time of a cached entry is found to
* be beyond the dup time window.
*
* Of course this assumes that the input trace file is
* "well-formed" in the sense that the packet timestamps are
* in strict chronologically increasing order (which is NOT
* always the case!!).
*
* The fd_hash[] table was deliberately created large (1,000,000).
* Looking for time related duplicates in large trace files with
* non-fractional dup time window values can potentially take
* a long time to complete.
*/
for (i = cur_dup_entry - 1;; i--) {
nstime_t delta;
int cmp;
if (i < 0)
i = dup_window - 1;
if (i == cur_dup_entry) {
/*
* We've decremented back to where we started.
* Check no more!
*/
break;
}
if (nstime_is_unset(&(fd_hash[i].frame_time))) {
/*
* We've decremented to an unused fd_hash[] entry.
* Check no more!
*/
break;
}
nstime_delta(&delta, current, &fd_hash[i].frame_time);
if (delta.secs < 0 || delta.nsecs < 0) {
/*
* A negative delta implies that the current packet
* has an absolute timestamp less than the cached packet
* that it is being compared to. This is NOT a normal
* situation since trace files usually have packets in
* chronological order (oldest to newest).
*
* There are several possible ways to deal with this:
* 1. 'continue' dup checking with the next cached frame.
* 2. 'break' from looking for a duplicate of the current frame.
* 3. Take the absolute value of the delta and see if that
* falls within the specified dup time window.
*
* Currently this code does option 1. But it would pretty
* easy to add yet-another-editcap-option to select one of
* the other behaviors for dealing with out-of-sequence
* packets.
*/
continue;
}
cmp = nstime_cmp(&delta, &relative_time_window);
if (cmp > 0) {
/*
* The delta time indicates that we are now looking at
* cached packets beyond the specified dup time window.
* Check no more!
*/
break;
} else if (fd_hash[i].len == fd_hash[cur_dup_entry].len
&& memcmp(fd_hash[i].digest, fd_hash[cur_dup_entry].digest, 16) == 0) {
return true;
}
}
return false;
}
static void
mutate_packet_data(wtap_rec *rec, uint8_t *buf, uint32_t change_offset, uint64_t count)
{
uint32_t caplen;
unsigned real_data_start = 0;
caplen = 0;
switch (rec->rec_type) {
case REC_TYPE_PACKET:
caplen = rec->rec_header.packet_header.caplen;
/*
* Protect some non-protocol data.
* XXX - any reason not to fuzz this part?
*/
if (rec->rec_header.packet_header.pkt_encap == WTAP_ENCAP_CATAPULT_DCT2000)
real_data_start = find_dct2000_real_data(buf);
break;
case REC_TYPE_FT_SPECIFIC_EVENT:
case REC_TYPE_FT_SPECIFIC_REPORT:
caplen = rec->rec_header.ft_specific_header.record_len;
break;
case REC_TYPE_SYSCALL:
caplen = rec->rec_header.syscall_header.event_filelen;
break;
case REC_TYPE_SYSTEMD_JOURNAL_EXPORT:
caplen = rec->rec_header.systemd_journal_export_header.record_len;
break;
default:
/* We don't mutate anything else. */
return;
}
if (change_offset > caplen) {
fprintf(stderr, "change offset %u is longer than caplen %u in packet %" PRIu64 "\n",
change_offset, caplen, count);
return;
}
real_data_start += change_offset;
for (unsigned i = real_data_start; i < caplen; i++) {
if (rand() <= err_prob * RAND_MAX) {
int err_type = rand() / (RAND_MAX / ERR_WT_TOTAL + 1);
if (err_type < ERR_WT_BIT) {
buf[i] ^= 1 << (rand() / (RAND_MAX / 8 + 1));
err_type = ERR_WT_TOTAL;
} else {
err_type -= ERR_WT_BYTE;
}
if (err_type < ERR_WT_BYTE) {
buf[i] = rand() / (RAND_MAX / 255 + 1);
err_type = ERR_WT_TOTAL;
} else {
err_type -= ERR_WT_BYTE;
}
if (err_type < ERR_WT_ALNUM) {
buf[i] = ALNUM_CHARS[rand() / (RAND_MAX / ALNUM_LEN + 1)];
err_type = ERR_WT_TOTAL;
} else {
err_type -= ERR_WT_ALNUM;
}
if (err_type < ERR_WT_FMT) {
if (i < caplen - 2)
(void) g_strlcpy((char*) &buf[i], "%s", 2);
err_type = ERR_WT_TOTAL;
} else {
err_type -= ERR_WT_FMT;
}
if (err_type < ERR_WT_AA) {
for (unsigned j = i; j < caplen; j++)
buf[j] = 0xAA;
i = caplen;
}
}
}
}
static void
print_usage(FILE *output)
{
fprintf(output, "\n");
fprintf(output, "Usage: editcap [options] ... <infile> <outfile> [ <packet#>[-<packet#>] ... ]\n");
fprintf(output, "\n");
fprintf(output, "<infile> and <outfile> must both be present; use '-' for stdin or stdout.\n");
fprintf(output, "A single packet or a range of packets can be selected.\n");
fprintf(output, "\n");
fprintf(output, "Packet selection:\n");
fprintf(output, " -r keep the selected packets; default is to delete them.\n");
fprintf(output, " -A <start time> only read packets whose timestamp is after (or equal\n");
fprintf(output, " to) the given time.\n");
fprintf(output, " -B <stop time> only read packets whose timestamp is before the\n");
fprintf(output, " given time.\n");
fprintf(output, " Time format for -A/-B options is\n");
fprintf(output, " YYYY-MM-DDThh:mm:ss[.nnnnnnnnn][Z|+-hh:mm]\n");
fprintf(output, " Unix epoch timestamps are also supported.\n");
fprintf(output, "\n");
fprintf(output, "Duplicate packet removal:\n");
fprintf(output, " --novlan remove vlan info from packets before checking for duplicates.\n");
fprintf(output, " -d remove packet if duplicate (window == %d).\n", DEFAULT_DUP_DEPTH);
fprintf(output, " -D <dup window> remove packet if duplicate; configurable <dup window>.\n");
fprintf(output, " Valid <dup window> values are 0 to %d.\n", MAX_DUP_DEPTH);
fprintf(output, " NOTE: A <dup window> of 0 with -V (verbose option) is\n");
fprintf(output, " useful to print MD5 hashes.\n");
fprintf(output, " -w <dup time window> remove packet if duplicate packet is found EQUAL TO OR\n");
fprintf(output, " LESS THAN <dup time window> prior to current packet.\n");
fprintf(output, " A <dup time window> is specified in relative seconds\n");
fprintf(output, " (e.g. 0.000001).\n");
fprintf(output, " NOTE: The use of the 'Duplicate packet removal' options with\n");
fprintf(output, " other editcap options except -V may not always work as expected.\n");
fprintf(output, " Specifically the -r, -t or -S options will very likely NOT have the\n");
fprintf(output, " desired effect if combined with the -d, -D or -w.\n");
fprintf(output, " --skip-radiotap-header skip radiotap header when checking for packet duplicates.\n");
fprintf(output, " Useful when processing packets captured by multiple radios\n");
fprintf(output, " on the same channel in the vicinity of each other.\n");
fprintf(output, " --set-unused set unused byts to zero in sll link addr.\n");
fprintf(output, "\n");
fprintf(output, "Packet manipulation:\n");
fprintf(output, " -s <snaplen> truncate each packet to max. <snaplen> bytes of data.\n");
fprintf(output, " -C [offset:]<choplen> chop each packet by <choplen> bytes. Positive values\n");
fprintf(output, " chop at the packet beginning, negative values at the\n");
fprintf(output, " packet end. If an optional offset precedes the length,\n");
fprintf(output, " then the bytes chopped will be offset from that value.\n");
fprintf(output, " Positive offsets are from the packet beginning,\n");
fprintf(output, " negative offsets are from the packet end. You can use\n");
fprintf(output, " this option more than once, allowing up to 2 chopping\n");
fprintf(output, " regions within a packet provided that at least 1\n");
fprintf(output, " choplen is positive and at least 1 is negative.\n");
fprintf(output, " -L adjust the frame (i.e. reported) length when chopping\n");
fprintf(output, " and/or snapping.\n");
fprintf(output, " -t <time adjustment> adjust the timestamp of each packet.\n");
fprintf(output, " <time adjustment> is in relative seconds (e.g. -0.5).\n");
fprintf(output, " -S <strict adjustment> adjust timestamp of packets if necessary to ensure\n");
fprintf(output, " strict chronological increasing order. The <strict\n");
fprintf(output, " adjustment> is specified in relative seconds with\n");
fprintf(output, " values of 0 or 0.000001 being the most reasonable.\n");
fprintf(output, " A negative adjustment value will modify timestamps so\n");
fprintf(output, " that each packet's delta time is the absolute value\n");
fprintf(output, " of the adjustment specified. A value of -0 will set\n");
fprintf(output, " all packets to the timestamp of the first packet.\n");
fprintf(output, " -E <error probability> set the probability (between 0.0 and 1.0 incl.) that\n");
fprintf(output, " a particular packet byte will be randomly changed.\n");
fprintf(output, " -o <change offset> When used in conjunction with -E, skip some bytes from the\n");
fprintf(output, " beginning of the packet. This allows one to preserve some\n");
fprintf(output, " bytes, in order to have some headers untouched.\n");
fprintf(output, " --seed <seed> When used in conjunction with -E, set the seed to use for\n");
fprintf(output, " the pseudo-random number generator. This allows one to\n");
fprintf(output, " repeat a particular sequence of errors.\n");
fprintf(output, " -I <bytes to ignore> ignore the specified number of bytes at the beginning\n");
fprintf(output, " of the frame during MD5 hash calculation, unless the\n");
fprintf(output, " frame is too short, then the full frame is used.\n");
fprintf(output, " Useful to remove duplicated packets taken on\n");
fprintf(output, " several routers (different mac addresses for\n");
fprintf(output, " example).\n");
fprintf(output, " e.g. -I 26 in case of Ether/IP will ignore\n");
fprintf(output, " ether(14) and IP header(20 - 4(src ip) - 4(dst ip)).\n");
fprintf(output, " -a <framenum>:<comment> Add or replace comment for given frame number\n");
fprintf(output, "\n");
fprintf(output, "Output File(s):\n");
fprintf(output, " if the output file(s) have the .gz extension, then\n");
fprintf(output, " gzip compression will be used\n");
fprintf(output, " -c <packets per file> split the packet output to different files based on\n");
fprintf(output, " uniform packet counts with a maximum of\n");
fprintf(output, " <packets per file> each.\n");
fprintf(output, " -i <seconds per file> split the packet output to different files based on\n");
fprintf(output, " uniform time intervals with a maximum of\n");
fprintf(output, " <seconds per file> each.\n");
fprintf(output, " -F <capture type> set the output file type; default is pcapng.\n");
fprintf(output, " An empty \"-F\" option will list the file types.\n");