src/tcpedit/plugins/dlt_user/user.c
/* $Id$ */
/*
* Copyright (c) 2001-2010 Aaron Turner <aturner at synfin dot net>
* Copyright (c) 2013-2022 Fred Klassen <tcpreplay at appneta dot com> - AppNeta
*
* The Tcpreplay Suite of tools 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 3 of the
* License, or with the authors permission any later version.
*
* The Tcpreplay Suite 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 the Tcpreplay Suite. If not, see <http://www.gnu.org/licenses/>.
*/
#include "user.h"
#include "dlt_utils.h"
#include "tcpedit.h"
#include "tcpedit_stub.h"
#include <stdlib.h>
#include <string.h>
static char dlt_name[] = "user";
static char _U_ dlt_prefix[] = "user";
static uint16_t dlt_value = DLT_USER0;
/*
* Function to register ourselves. This function is always called, regardless
* of what DLT types are being used, so it shouldn't be allocating extra buffers
* or anything like that (use the dlt_user_init() function below for that).
* Tasks:
* - Create a new plugin struct
* - Fill out the provides/requires bit masks. Note: Only specify which fields are
* actually in the header.
* - Add the plugin to the context's plugin chain
* Returns: TCPEDIT_ERROR | TCPEDIT_OK | TCPEDIT_WARN
*/
int
dlt_user_register(tcpeditdlt_t *ctx)
{
tcpeditdlt_plugin_t *plugin;
assert(ctx);
/* create a new plugin structure */
plugin = tcpedit_dlt_newplugin();
/* FIXME: set what we provide & require */
plugin->provides += PLUGIN_MASK_PROTO + PLUGIN_MASK_SRCADDR + PLUGIN_MASK_DSTADDR;
plugin->
requires
+= 0; // PLUGIN_MASK_PROTO + PLUGIN_MASK_SRCADDR + PLUGIN_MASK_DSTADDR;
/* what is our DLT value? */
plugin->dlt = dlt_value;
/* set the prefix name of our plugin. This is also used as the prefix for our options */
plugin->name = safe_strdup(dlt_prefix);
/*
* Point to our functions, note, you need a function for EVERY method.
* Even if it is only an empty stub returning success.
*/
plugin->plugin_init = dlt_user_init;
plugin->plugin_cleanup = dlt_user_cleanup;
plugin->plugin_parse_opts = dlt_user_parse_opts;
plugin->plugin_decode = dlt_user_decode;
plugin->plugin_encode = dlt_user_encode;
plugin->plugin_proto = dlt_user_proto;
plugin->plugin_l2addr_type = dlt_user_l2addr_type;
plugin->plugin_l2len = dlt_user_l2len;
plugin->plugin_get_layer3 = dlt_user_get_layer3;
plugin->plugin_merge_layer3 = dlt_user_merge_layer3;
plugin->plugin_get_mac = dlt_user_get_mac;
/* add it to the available plugin list */
return tcpedit_dlt_addplugin(ctx, plugin);
}
/*
* Initializer function. This function is called only once, if and only if
* this plugin will be utilized. Remember, if you need to keep track of any state,
* store it in your plugin->config, not a global!
* Returns: TCPEDIT_ERROR | TCPEDIT_OK | TCPEDIT_WARN
*/
int
dlt_user_init(tcpeditdlt_t *ctx)
{
tcpeditdlt_plugin_t *plugin;
user_config_t *config;
assert(ctx);
if ((plugin = tcpedit_dlt_getplugin(ctx, dlt_value)) == NULL) {
tcpedit_seterr(ctx->tcpedit, "Unable to initialize unregistered plugin %s", dlt_name);
return TCPEDIT_ERROR;
}
/* allocate memory for our decode extra data - plus some space for
* other DLT decodes
*/
if (ctx->decoded_extra_size > 0) {
if (ctx->decoded_extra_size < USER_L2MAXLEN) {
ctx->decoded_extra_size = USER_L2MAXLEN;
ctx->decoded_extra = safe_realloc(ctx->decoded_extra, ctx->decoded_extra_size);
}
} else {
ctx->decoded_extra_size = USER_L2MAXLEN;
ctx->decoded_extra = safe_malloc(ctx->decoded_extra_size);
}
/* allocate memory for our config data */
plugin->config_size = sizeof(user_config_t);
plugin->config = safe_malloc(plugin->config_size);
config = (user_config_t *)plugin->config;
config->length = -1;
/* do nothing */
return TCPEDIT_OK; /* success */
}
/*
* Since this is used in a library, we should manually clean up after ourselves
* Unless you allocated some memory in dlt_user_init(), this is just an stub.
* Returns: TCPEDIT_ERROR | TCPEDIT_OK | TCPEDIT_WARN
*/
int
dlt_user_cleanup(tcpeditdlt_t *ctx)
{
tcpeditdlt_plugin_t *plugin;
assert(ctx);
if ((plugin = tcpedit_dlt_getplugin(ctx, dlt_value)) == NULL) {
tcpedit_seterr(ctx->tcpedit, "Unable to cleanup unregistered plugin %s", dlt_name);
return TCPEDIT_ERROR;
}
safe_free(plugin->name);
plugin->name = NULL;
safe_free(plugin->config);
plugin->config = NULL;
plugin->config_size = 0;
return TCPEDIT_OK; /* success */
}
/*
* This is where you should define all your AutoGen AutoOpts option parsing.
* Any user specified option should have it's bit turned on in the 'provides'
* bit mask.
* Returns: TCPEDIT_ERROR | TCPEDIT_OK | TCPEDIT_WARN
*/
int
dlt_user_parse_opts(tcpeditdlt_t *ctx)
{
tcpeditdlt_plugin_t *plugin;
user_config_t *config;
assert(ctx);
plugin = tcpedit_dlt_getplugin(ctx, dlt_value);
if (!plugin)
return TCPEDIT_ERROR;
config = plugin->config;
if (plugin->config_size < sizeof(*config))
return TCPEDIT_ERROR;
/*
* --user-dlt will override the output DLT type, otherwise we'll use
* the DLT of the decoder
*/
if (HAVE_OPT(USER_DLT)) {
config->dlt = OPT_VALUE_USER_DLT;
} else {
config->dlt = ctx->decoder->dlt;
}
/* --user-dlink */
if (HAVE_OPT(USER_DLINK)) {
int ct = STACKCT_OPT(USER_DLINK);
char **list = (char **)STACKLST_OPT(USER_DLINK);
int first = 1;
do {
char *p = *list++;
if (first) {
config->length = read_hexstring(p, config->l2server, USER_L2MAXLEN);
memcpy(config->l2client, config->l2server, config->length);
} else {
if (config->length != read_hexstring(p, config->l2client, USER_L2MAXLEN)) {
tcpedit_seterr(ctx->tcpedit, "%s", "both --dlink's must contain the same number of bytes");
return TCPEDIT_ERROR;
}
}
first = 0;
} while (--ct > 0);
}
return TCPEDIT_OK; /* success */
}
/* you should never decode packets with this plugin! */
int
dlt_user_decode(tcpeditdlt_t *ctx, const u_char *packet, int _U_ pktlen)
{
assert(ctx);
assert(packet);
tcpedit_seterr(ctx->tcpedit, "%s", "DLT_USER0 plugin does not support packet decoding");
return TCPEDIT_ERROR;
}
/*
* Function to encode the layer 2 header back into the packet.
* Returns: total packet len or TCPEDIT_ERROR
*/
int
dlt_user_encode(tcpeditdlt_t *ctx, u_char *packet, int pktlen, tcpr_dir_t dir)
{
user_config_t *config;
tcpeditdlt_plugin_t *plugin;
assert(ctx);
assert(packet);
if (pktlen == 0)
return TCPEDIT_ERROR;
plugin = tcpedit_dlt_getplugin(ctx, dlt_value);
if (!plugin)
return TCPEDIT_ERROR;
config = plugin->config;
if (plugin->config_size < sizeof(*config))
return TCPEDIT_ERROR;
/* Make room for our new l2 header if l2len != config->length */
if (ctx->l2len > config->length) {
memmove(packet + config->length, packet + ctx->l2len, pktlen - ctx->l2len);
} else if (ctx->l2len < config->length) {
u_char *tmpbuff = safe_malloc(pktlen);
memcpy(tmpbuff, packet, pktlen);
memcpy(packet + config->length, (tmpbuff + ctx->l2len), pktlen - ctx->l2len);
safe_free(tmpbuff);
}
/* update the total packet length */
pktlen += config->length - ctx->l2len;
if (dir == TCPR_DIR_C2S) {
memcpy(packet, config->l2client, config->length);
} else if (dir == TCPR_DIR_S2C) {
memcpy(packet, config->l2server, config->length);
} else {
tcpedit_seterr(ctx->tcpedit, "%s", "Encoders only support C2S or C2S!");
return TCPEDIT_ERROR;
}
return pktlen; /* success */
}
/*
* Function returns the Layer 3 protocol type of the given packet, or TCPEDIT_ERROR on error
*/
int
dlt_user_proto(tcpeditdlt_t *ctx, const u_char *packet, int _U_ pktlen)
{
assert(ctx);
assert(packet);
/* calling this for DLT_USER0 is broken */
tcpedit_seterr(ctx->tcpedit, "%s", "Nonsensical calling of dlt_user_proto()");
return TCPEDIT_ERROR;
}
/*
* Function returns a pointer to the layer 3 protocol header or NULL on error
*/
u_char *
dlt_user_get_layer3(tcpeditdlt_t *ctx, u_char *packet, int pktlen)
{
int l2len;
assert(ctx);
assert(packet);
/* FIXME: Is there anything else we need to do?? */
l2len = dlt_user_l2len(ctx, packet, pktlen);
if (l2len == -1 || pktlen < l2len)
return NULL;
return tcpedit_dlt_l3data_copy(ctx, packet, pktlen, l2len);
}
/*
* function merges the packet (containing L2 and old L3) with the l3data buffer
* containing the new l3 data. Note, if L2 % 4 == 0, then they're pointing to the
* same buffer, otherwise there was a memcpy involved on strictly aligned architectures
* like SPARC
*/
u_char *
dlt_user_merge_layer3(tcpeditdlt_t *ctx, u_char *packet, int pktlen, u_char *ipv4_data, u_char *ipv6_data)
{
int l2len;
assert(ctx);
assert(packet);
assert(ipv4_data || ipv6_data);
/* FIXME: Is there anything else we need to do?? */
l2len = dlt_user_l2len(ctx, packet, pktlen);
if (l2len == TCPEDIT_ERROR || pktlen < l2len)
return NULL;
return tcpedit_dlt_l3data_merge(ctx, packet, pktlen, ipv4_data ?: ipv6_data, l2len);
}
/*
* return the length of the L2 header of the current packet
*/
int
dlt_user_l2len(tcpeditdlt_t *ctx, const u_char *packet, int _U_ pktlen)
{
tcpeditdlt_plugin_t *plugin;
user_config_t *config;
assert(ctx);
assert(packet);
plugin = tcpedit_dlt_getplugin(ctx, dlt_value);
if (!plugin)
return TCPEDIT_ERROR;
config = plugin->config;
if (plugin->config_size < sizeof(*config))
return TCPEDIT_ERROR;
return config->length;
}
/*
* return a static pointer to the source/destination MAC address
* return NULL on error/address doesn't exist
*/
u_char *
dlt_user_get_mac(tcpeditdlt_t *ctx, _U_ tcpeditdlt_mac_type_t mac, const u_char *packet, int _U_ pktlen)
{
assert(ctx);
assert(packet);
/* we don't know the format of USER DLT, hence always return NULL */
return (NULL);
}
tcpeditdlt_l2addr_type_t
dlt_user_l2addr_type(void)
{
return NONE;
}
/*
* Need this special function for dlt_plugins.c:tcpedit_dlt_output_dlt()
*/
uint16_t
dlt_user_get_output_dlt(tcpeditdlt_t *ctx)
{
tcpeditdlt_plugin_t *plugin;
user_config_t *config;
assert(ctx);
plugin = tcpedit_dlt_getplugin(ctx, dlt_value);
config = plugin->config;
return config->dlt;
}