src/tcpedit/plugins/dlt_raw/raw.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 "raw.h"
#include "dlt_utils.h"
#include "tcpedit.h"
#include "tcpedit_stub.h"
#include <stdlib.h>
#include <string.h>
static char dlt_name[] = "raw";
static char _U_ dlt_prefix[] = "raw";
static uint16_t dlt_value = DLT_RAW;
/*
* DLT_RAW is basically a zero length L2 header for IPv4 & IPv6 packets
*/
/*
* 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_raw_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_raw_register(tcpeditdlt_t *ctx)
{
tcpeditdlt_plugin_t *plugin;
assert(ctx);
/* create a new plugin structure */
plugin = tcpedit_dlt_newplugin();
/* set what we provide & require */
plugin->provides += PLUGIN_MASK_PROTO;
/* 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_raw_init;
plugin->plugin_cleanup = dlt_raw_cleanup;
plugin->plugin_parse_opts = dlt_raw_parse_opts;
plugin->plugin_decode = dlt_raw_decode;
plugin->plugin_encode = dlt_raw_encode;
plugin->plugin_proto = dlt_raw_proto;
plugin->plugin_l2addr_type = dlt_raw_l2addr_type;
plugin->plugin_l2len = dlt_raw_l2len;
plugin->plugin_get_layer3 = dlt_raw_get_layer3;
plugin->plugin_merge_layer3 = dlt_raw_merge_layer3;
plugin->plugin_get_mac = dlt_raw_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_raw_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 config data */
if (ctx->decoded_extra_size > 0) {
if (ctx->decoded_extra_size < sizeof(raw_extra_t)) {
ctx->decoded_extra_size = sizeof(raw_extra_t);
ctx->decoded_extra = safe_realloc(ctx->decoded_extra, ctx->decoded_extra_size);
}
} else {
ctx->decoded_extra_size = sizeof(raw_extra_t);
ctx->decoded_extra = safe_malloc(ctx->decoded_extra_size);
}
/* allocate memory for our config data */
plugin->config_size = sizeof(raw_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_raw_init(), this is just an stub.
* Returns: TCPEDIT_ERROR | TCPEDIT_OK | TCPEDIT_WARN
*/
int
dlt_raw_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_raw_parse_opts(tcpeditdlt_t *ctx)
{
assert(ctx);
/* no op */
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_raw_decode(tcpeditdlt_t *ctx, const u_char *packet, int pktlen)
{
int proto;
assert(ctx);
assert(packet);
if (pktlen == 0)
return TCPEDIT_ERROR;
if ((proto = dlt_raw_proto(ctx, packet, pktlen)) == TCPEDIT_ERROR)
return TCPEDIT_ERROR;
ctx->proto = (uint16_t)proto;
ctx->l2len = 0;
return TCPEDIT_OK; /* success */
}
/*
* Function to encode the layer 2 header back into the packet.
* Returns: total packet len or TCPEDIT_ERROR
*/
int
dlt_raw_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_RAW 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
*/
int
dlt_raw_proto(tcpeditdlt_t *ctx, const u_char *packet, int pktlen)
{
struct tcpr_ipv4_hdr *iphdr;
assert(ctx);
assert(packet);
int protocol;
if (pktlen < (int)sizeof(*iphdr))
return TCPEDIT_ERROR;
iphdr = (struct tcpr_ipv4_hdr *)packet;
if (iphdr->ip_v == 0x04) {
protocol = ETHERTYPE_IP;
} else if (iphdr->ip_v == 0x06) {
protocol = ETHERTYPE_IP6;
} else {
tcpedit_seterr(ctx->tcpedit, "%s", "Unsupported DLT_RAW packet: doesn't look like IPv4 or IPv6");
return TCPEDIT_ERROR;
}
return htons(protocol);
}
/*
* Function returns a pointer to the layer 3 protocol header or NULL on error
*/
u_char *
dlt_raw_get_layer3(tcpeditdlt_t *ctx, u_char *packet, _U_ int pktlen)
{
assert(ctx);
assert(packet);
/* raw has a zero byte header, so this is basically a non-op */
return packet;
}
/*
* 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_raw_merge_layer3(tcpeditdlt_t *ctx, u_char *packet, _U_ int pktlen, u_char *ipv4_data, u_char *ipv6_data)
{
assert(ctx);
assert(packet);
assert(ipv4_data || ipv6_data);
/* raw has a zero byte header, so this is basically a non-op */
return packet;
}
/*
* return the length of the L2 header of the current packet
*/
int
dlt_raw_l2len(tcpeditdlt_t *ctx, const u_char *packet, _U_ int pktlen)
{
assert(ctx);
assert(packet);
return 0;
}
/*
* return a static pointer to the source/destination MAC address
* return NULL on error/address doesn't exist
*/
u_char *
dlt_raw_get_mac(tcpeditdlt_t *ctx, _U_ tcpeditdlt_mac_type_t mac, const u_char *packet, _U_ int pktlen)
{
assert(ctx);
assert(packet);
return (NULL);
}
tcpeditdlt_l2addr_type_t
dlt_raw_l2addr_type(void)
{
return NONE;
}