src/tcpedit/plugins/dlt_radiotap/radiotap.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 "radiotap.h"
#include "../dlt_ieee80211/ieee80211.h"
#include "dlt_utils.h"
#include "tcpedit.h"
#include "tcpedit_stub.h"
#include <stdlib.h>
#include <string.h>
/* edit these variables to taste */
static char dlt_name[] = "radiotap";
_U_ static char dlt_prefix[] = "radiotap";
static uint16_t dlt_value = DLT_IEEE802_11_RADIO;
/*
* The Radiotap header plugin utilizes the 802.11 plugin internally to do all the work
* we just eat the radiotap header itself and pass the resulting buffer to the ieee80211
* plugin.
*/
static u_char *dlt_radiotap_get_80211(tcpeditdlt_t *ctx, const u_char *packet, int pktlen, int radiolen);
/*
* 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_radiotap_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_radiotap_register(tcpeditdlt_t *ctx)
{
tcpeditdlt_plugin_t *plugin;
assert(ctx);
/* create a new plugin structure */
plugin = tcpedit_dlt_newplugin();
/* we're a decoder only plugin, copy from ieee802.11 */
plugin->provides += PLUGIN_MASK_PROTO + PLUGIN_MASK_SRCADDR + PLUGIN_MASK_DSTADDR;
plugin->
requires
+= 0;
/* 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_name);
/*
* 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_radiotap_init;
plugin->plugin_cleanup = dlt_radiotap_cleanup;
plugin->plugin_parse_opts = dlt_radiotap_parse_opts;
plugin->plugin_decode = dlt_radiotap_decode;
plugin->plugin_encode = dlt_radiotap_encode;
plugin->plugin_proto = dlt_radiotap_proto;
plugin->plugin_l2addr_type = dlt_radiotap_l2addr_type;
plugin->plugin_l2len = dlt_radiotap_80211_l2len;
plugin->plugin_get_layer3 = dlt_radiotap_get_layer3;
plugin->plugin_merge_layer3 = dlt_radiotap_merge_layer3;
plugin->plugin_get_mac = dlt_radiotap_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_radiotap_init(tcpeditdlt_t *ctx)
{
tcpeditdlt_plugin_t *plugin;
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 */
if (ctx->decoded_extra_size > 0) {
if (ctx->decoded_extra_size < sizeof(radiotap_extra_t)) {
ctx->decoded_extra_size = sizeof(radiotap_extra_t);
ctx->decoded_extra = safe_realloc(ctx->decoded_extra, ctx->decoded_extra_size);
}
} else {
ctx->decoded_extra_size = sizeof(radiotap_extra_t);
ctx->decoded_extra = safe_malloc(ctx->decoded_extra_size);
}
/* allocate memory for our config data */
plugin->config_size = sizeof(radiotap_config_t);
plugin->config = safe_malloc(plugin->config_size);
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_radiotap_init(), this is just an stub.
* Returns: TCPEDIT_ERROR | TCPEDIT_OK | TCPEDIT_WARN
*/
int
dlt_radiotap_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_radiotap_parse_opts(tcpeditdlt_t *ctx)
{
assert(ctx);
/* we have none */
return TCPEDIT_OK; /* success */
}
/*
* Function to decode the layer 2 header in the packet.
* You need to fill out:
* - ctx->l2len
* - ctx->srcaddr
* - ctx->dstaddr
* - ctx->proto
* - ctx->decoded_extra
* Returns: TCPEDIT_ERROR | TCPEDIT_OK | TCPEDIT_WARN
*/
int
dlt_radiotap_decode(tcpeditdlt_t *ctx, const u_char *packet, int pktlen)
{
int radiolen, rcode;
u_char *data;
assert(ctx);
assert(packet);
if (pktlen < (int)sizeof(radiotap_hdr_t))
return TCPEDIT_ERROR;
radiolen = dlt_radiotap_l2len(ctx, packet, pktlen);
data = dlt_radiotap_get_80211(ctx, packet, pktlen, radiolen);
if (!data)
return TCPEDIT_ERROR;
/* ieee80211 decoder fills out everything */
rcode = dlt_ieee80211_decode(ctx, data, pktlen - radiolen);
/* need to override the ieee802.11 l2 length result */
ctx->l2len = dlt_radiotap_80211_l2len(ctx, packet, pktlen);
return (ctx->l2len > 0) ? rcode : TCPEDIT_ERROR;
}
/*
* Function to encode the layer 2 header back into the packet.
* Returns: total packet len or TCPEDIT_ERROR
*/
int
dlt_radiotap_encode(tcpeditdlt_t *ctx, u_char *packet, _U_ int pktlen, _U_ tcpr_dir_t dir)
{
assert(ctx);
assert(packet);
tcpedit_seterr(ctx->tcpedit, "%s", "DLT_IEEE802_11_RADIO plugin does not support packet encoding");
return TCPEDIT_ERROR;
}
/*
* Function returns the Layer 3 protocol type of the given packet, or TCPEDIT_ERROR on error
* Make sure you return this in host byte order since all the comparisons will be
* against the ETHERTYPE_* values which are oddly in host byte order.
*/
int
dlt_radiotap_proto(tcpeditdlt_t *ctx, const u_char *packet, int pktlen)
{
int radiolen;
u_char *data;
assert(ctx);
assert(packet);
if (pktlen < (int)sizeof(radiotap_hdr_t))
return TCPEDIT_ERROR;
radiolen = dlt_radiotap_l2len(ctx, packet, pktlen);
if (radiolen < 0 || radiolen > pktlen)
return TCPEDIT_ERROR;
data = dlt_radiotap_get_80211(ctx, packet, pktlen, radiolen);
return dlt_ieee80211_proto(ctx, data, pktlen - radiolen);
}
/*
* Function returns a pointer to the layer 3 protocol header or NULL on error
*/
u_char *
dlt_radiotap_get_layer3(tcpeditdlt_t *ctx, u_char *packet, int pktlen)
{
int radiolen, l2len;
u_char *data;
assert(ctx);
assert(packet);
radiolen = dlt_radiotap_l2len(ctx, packet, pktlen);
data = dlt_radiotap_get_80211(ctx, packet, pktlen, radiolen);
l2len = dlt_ieee80211_l2len(ctx, data, pktlen - radiolen);
return tcpedit_dlt_l3data_copy(ctx, data, pktlen - radiolen, 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_radiotap_merge_layer3(tcpeditdlt_t *ctx, u_char *packet, int pktlen, u_char *ipv4_data, u_char *ipv6_data)
{
int radiolen, l2len;
u_char *data;
assert(ctx);
assert(packet);
assert(ipv4_data || ipv6_data);
radiolen = dlt_radiotap_l2len(ctx, packet, pktlen);
data = dlt_radiotap_get_80211(ctx, packet, pktlen, radiolen);
l2len = dlt_ieee80211_l2len(ctx, data, pktlen);
return tcpedit_dlt_l3data_merge(ctx, data, pktlen - radiolen, ipv4_data ?: ipv6_data, l2len);
}
/*
* return a static pointer to the source/destination MAC address
* return NULL on error/address doesn't exist
*/
u_char *
dlt_radiotap_get_mac(tcpeditdlt_t *ctx, tcpeditdlt_mac_type_t mac, const u_char *packet, int pktlen)
{
int radiolen;
u_char *data;
assert(ctx);
assert(packet);
radiolen = dlt_radiotap_l2len(ctx, packet, pktlen);
if (pktlen < radiolen)
return NULL;
data = dlt_radiotap_get_80211(ctx, packet, pktlen, radiolen);
return dlt_ieee80211_get_mac(ctx, mac, data, pktlen - radiolen);
}
/*
* return the length of the L2 header of the current packet
*/
int
dlt_radiotap_l2len(tcpeditdlt_t *ctx, const u_char *packet, int pktlen)
{
uint16_t radiolen;
assert(ctx);
assert(packet);
if (pktlen < 4)
return -1;
memcpy(&radiolen, &packet[2], 2);
/* little endian to host */
radiolen = ntohs(SWAPSHORT(radiolen));
return (int)radiolen;
}
/*
* return the length of the L2 header w/ 802.11 header of the current packet
*/
int
dlt_radiotap_80211_l2len(tcpeditdlt_t *ctx, const u_char *packet, int pktlen)
{
int radiolen, res;
u_char *data;
radiolen = dlt_radiotap_l2len(ctx, packet, pktlen);
if (radiolen == -1)
return TCPEDIT_ERROR;
data = dlt_radiotap_get_80211(ctx, packet, pktlen, radiolen);
res = dlt_ieee80211_l2len(ctx, data, pktlen - radiolen);
if (res == -1)
return TCPEDIT_ERROR;
radiolen += res;
return radiolen;
}
tcpeditdlt_l2addr_type_t
dlt_radiotap_l2addr_type(void)
{
/* FIXME: return the tcpeditdlt_l2addr_type_t value that this DLT uses */
return ETHERNET;
}
/*
* returns a buffer to the 802.11 header in the packet.
* This does an optimization of only doing a memcpy() once per packet
* since we track which was the last packet # we copied.
*/
static u_char *
dlt_radiotap_get_80211(tcpeditdlt_t *ctx, const u_char *packet, int pktlen, int radiolen)
{
radiotap_extra_t *extra;
static COUNTER lastpacket = 0;
if (ctx->decoded_extra_size < sizeof(*extra))
return NULL;
extra = (radiotap_extra_t *)(ctx->decoded_extra);
if (pktlen >= radiolen && (size_t)(pktlen - radiolen) >= sizeof(extra->packet) &&
lastpacket != ctx->tcpedit->runtime.packetnum) {
memcpy(extra->packet, &packet[radiolen], pktlen - radiolen);
lastpacket = ctx->tcpedit->runtime.packetnum;
}
return extra->packet;
}