src/tcpedit/plugins/dlt_jnpr_ether/jnpr_ether.c
/* $Id$ */
/*
* Copyright (c) 2006-2007 Aaron Turner.
* Copyright (c) 2013-2022 Fred Klassen <tcpreplay at appneta dot com> - AppNeta
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the names of the copyright owners nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
* IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "jnpr_ether.h"
#include "dlt_utils.h"
#include "jnpr_ether_types.h"
#include "tcpedit.h"
#include "tcpedit_stub.h"
#include <dlt_en10mb/en10mb.h>
#include <stdlib.h>
#include <string.h>
static char dlt_name[] = "jnpr_eth";
static uint16_t dlt_value = DLT_JUNIPER_ETHER;
/*
* 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_jnpr_ether_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_jnpr_ether_register(tcpeditdlt_t *ctx)
{
tcpeditdlt_plugin_t *plugin;
assert(ctx);
/* create a new plugin structure */
plugin = tcpedit_dlt_newplugin();
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_jnpr_ether_init;
plugin->plugin_post_init = dlt_jnpr_ether_post_init;
plugin->plugin_cleanup = dlt_jnpr_ether_cleanup;
plugin->plugin_parse_opts = dlt_jnpr_ether_parse_opts;
plugin->plugin_decode = dlt_jnpr_ether_decode;
plugin->plugin_encode = dlt_jnpr_ether_encode;
plugin->plugin_proto = dlt_jnpr_ether_proto;
plugin->plugin_l2addr_type = dlt_jnpr_ether_l2addr_type;
plugin->plugin_l2len = dlt_jnpr_ether_l2len;
plugin->plugin_get_layer3 = dlt_jnpr_ether_get_layer3;
plugin->plugin_merge_layer3 = dlt_jnpr_ether_merge_layer3;
plugin->plugin_get_mac = dlt_jnpr_ether_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_jnpr_ether_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 */
plugin->config_size = sizeof(jnpr_ether_config_t);
plugin->config = safe_malloc(plugin->config_size);
return TCPEDIT_OK; /* success */
}
/**
* Post init function. This function is called only once after init() and parse_opts()
* It basically allows decoders to properly initialize sub-plugins.
*/
int
dlt_jnpr_ether_post_init(tcpeditdlt_t *ctx)
{
jnpr_ether_config_t *config;
/* do nothing if we're not the decoder */
if (ctx->decoder->dlt != dlt_value)
return TCPEDIT_OK;
/* init our subcontext & decoder of en10mb */
config = (jnpr_ether_config_t *)ctx->encoder->config;
if (config->subctx == NULL)
config->subctx = tcpedit_dlt_init(ctx->tcpedit, DLT_EN10MB);
return TCPEDIT_OK;
}
/*
* Since this is used in a library, we should manually clean up after ourselves
* Unless you allocated some memory in dlt_jnpr_ether_init(), this is just an stub.
* Returns: TCPEDIT_ERROR | TCPEDIT_OK | TCPEDIT_WARN
*/
int
dlt_jnpr_ether_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;
if (plugin->config != NULL) {
/* clean up the en10mb plugin */
jnpr_ether_config_t *config;
config = (jnpr_ether_config_t *)ctx->encoder->config;
if (config->subctx != NULL)
tcpedit_dlt_cleanup(config->subctx);
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_jnpr_ether_parse_opts(tcpeditdlt_t *ctx)
{
assert(ctx);
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_jnpr_ether_decode(tcpeditdlt_t *ctx, const u_char *packet, int pktlen)
{
int jnpr_header_len = 0;
const u_char *ethernet = NULL;
jnpr_ether_config_t *config;
assert(ctx);
assert(packet);
/* MAGIC + Static fields + Extension Length */
if (pktlen < JUNIPER_ETHER_HEADER_LEN)
return TCPEDIT_ERROR;
config = (jnpr_ether_config_t *)ctx->encoder->config;
/* first, verify magic */
if (memcmp(packet, JUNIPER_ETHER_MAGIC, JUNIPER_ETHER_MAGIC_LEN) != 0) {
tcpedit_seterr(ctx->tcpedit, "Invalid magic 0x%02X%02X%02X", packet[0], packet[1], packet[2]);
return TCPEDIT_ERROR;
}
/* next make sure the L2 header is present */
if ((packet[JUNIPER_ETHER_OPTIONS_OFFSET] & JUNIPER_ETHER_L2PRESENT) != JUNIPER_ETHER_L2PRESENT) {
tcpedit_seterr(ctx->tcpedit, "Frame is missing L2 Header: %x", packet[JUNIPER_ETHER_OPTIONS_OFFSET]);
return TCPEDIT_ERROR;
}
/* then get the Juniper header length */
memcpy(&jnpr_header_len, &packet[JUNIPER_ETHER_EXTLEN_OFFSET], 2);
jnpr_header_len = ntohs(jnpr_header_len) + JUNIPER_ETHER_HEADER_LEN;
dbgx(1, "jnpr header len: %d", jnpr_header_len);
/* make sure the packet is big enough to find the Ethernet Header */
if (pktlen < jnpr_header_len + TCPR_ETH_H) {
tcpedit_seterr(ctx->tcpedit, "Frame is too short! %d < %d", pktlen, (jnpr_header_len + TCPR_ETH_H));
return TCPEDIT_ERROR;
}
ctx->l2len = jnpr_header_len;
/* jump to the appropriate offset */
ethernet = packet + jnpr_header_len;
/* let the en10mb plugin decode the rest */
if (tcpedit_dlt_decode(config->subctx, ethernet, (pktlen - jnpr_header_len)) == TCPEDIT_ERROR)
return TCPEDIT_ERROR;
/* copy the subdecoder state to our encoder state */
if (tcpedit_dlt_copy_decoder_state(ctx, config->subctx) == TCPEDIT_ERROR)
return TCPEDIT_ERROR;
return TCPEDIT_OK;
}
/*
* Function to encode the layer 2 header back into the packet.
* Returns: total packet len or TCPEDIT_ERROR
*/
int
dlt_jnpr_ether_encode(tcpeditdlt_t *ctx, u_char *packet, int pktlen, _U_ tcpr_dir_t dir)
{
assert(ctx);
assert(packet);
/* MAGIC + Static fields + Extension Length */
if (pktlen < JUNIPER_ETHER_HEADER_LEN)
return TCPEDIT_ERROR;
tcpedit_seterr(ctx->tcpedit, "%s", "DLT_JUNIPER_ETHER 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 value in NETWORK byte order!
*/
int
dlt_jnpr_ether_proto(tcpeditdlt_t *ctx, const u_char *packet, int pktlen)
{
int jnpr_hdr_len;
const u_char *ethernet;
jnpr_ether_config_t *config;
assert(ctx);
assert(packet);
/* MAGIC + Static fields + Extension Length */
if (pktlen < JUNIPER_ETHER_HEADER_LEN)
return TCPEDIT_ERROR;
config = (jnpr_ether_config_t *)ctx->encoder->config;
/* next make sure the L2 header is present */
if ((packet[JUNIPER_ETHER_OPTIONS_OFFSET] & JUNIPER_ETHER_L2PRESENT) != JUNIPER_ETHER_L2PRESENT) {
tcpedit_seterr(ctx->tcpedit, "Frame is missing L2 Header: %x", packet[JUNIPER_ETHER_OPTIONS_OFFSET]);
return TCPEDIT_ERROR;
}
/* then get the Juniper header length */
memcpy(&jnpr_hdr_len, &packet[JUNIPER_ETHER_EXTLEN_OFFSET], 2);
jnpr_hdr_len = ntohs(jnpr_hdr_len) + JUNIPER_ETHER_HEADER_LEN;
ethernet = packet + jnpr_hdr_len;
/* let the en10mb plugin do the rest of the work */
return tcpedit_dlt_proto(config->subctx, DLT_EN10MB, ethernet, (pktlen - jnpr_hdr_len));
}
/*
* Function returns a pointer to the layer 3 protocol header or NULL on error
*/
u_char *
dlt_jnpr_ether_get_layer3(tcpeditdlt_t *ctx, u_char *packet, int pktlen)
{
int l2len;
assert(ctx);
assert(packet);
/* next make sure the L2 header is present */
if ((packet[JUNIPER_ETHER_OPTIONS_OFFSET] & JUNIPER_ETHER_L2PRESENT) != JUNIPER_ETHER_L2PRESENT) {
tcpedit_seterr(ctx->tcpedit, "Frame is missing L2 Header: %x", packet[JUNIPER_ETHER_OPTIONS_OFFSET]);
return NULL;
}
l2len = dlt_jnpr_ether_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_jnpr_ether_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);
l2len = dlt_jnpr_ether_l2len(ctx, packet, pktlen);
if (l2len == -1 || pktlen < l2len)
return NULL;
return tcpedit_dlt_l3data_merge(ctx, packet, pktlen, 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_jnpr_ether_get_mac(tcpeditdlt_t *ctx, tcpeditdlt_mac_type_t mac, const u_char *packet, int pktlen)
{
const u_char *ethernet = NULL;
jnpr_ether_config_t *config;
int jnpr_hdr_len = 0;
assert(ctx);
assert(packet);
if (pktlen < JUNIPER_ETHER_EXTLEN_OFFSET + 2)
return NULL;
config = (jnpr_ether_config_t *)ctx->encoder->config;
/* first get the Juniper header length */
memcpy(&jnpr_hdr_len, &packet[JUNIPER_ETHER_EXTLEN_OFFSET], 2);
jnpr_hdr_len = ntohs(jnpr_hdr_len) + JUNIPER_ETHER_HEADER_LEN;
ethernet = packet + jnpr_hdr_len;
return dlt_en10mb_get_mac(config->subctx, mac, ethernet, (pktlen - jnpr_hdr_len));
}
/*
* return the length of the L2 header of the current packet
*/
int
dlt_jnpr_ether_l2len(tcpeditdlt_t *ctx, const u_char *packet, int pktlen)
{
int len, res;
jnpr_ether_config_t *config;
assert(ctx);
assert(packet);
if (pktlen < JUNIPER_ETHER_EXTLEN_OFFSET + 2)
return -1;
config = (jnpr_ether_config_t *)ctx->encoder->config;
/* first get the Juniper header length */
memcpy(&len, &packet[JUNIPER_ETHER_EXTLEN_OFFSET], 2);
len = ntohs(len) + JUNIPER_ETHER_HEADER_LEN;
dbgx(3, "juniper header len: %u", len);
/* add the 802.3 length */
res = tcpedit_dlt_l2len(config->subctx, DLT_EN10MB, (packet + len), (pktlen - len));
if (res == -1)
return TCPEDIT_ERROR;
len += res;
dbgx(3, "total l2len: %u", len);
/* and return that */
return len;
}
tcpeditdlt_l2addr_type_t
dlt_jnpr_ether_l2addr_type(void)
{
return ETHERNET;
}