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- /* $Id$ */
- /*
- * Copyright (c) 2001-2010 Aaron Turner <aturner at synfin dot net>
- * Copyright (c) 2013-2024 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 "hdlc.h"
- #include "dlt_utils.h"
- #include "tcpedit.h"
- #include "tcpedit_stub.h"
- #include <stdlib.h>
- #include <string.h>
- static char dlt_name[] = "hdlc";
- static char _U_ dlt_prefix[] = "hdlc";
- static uint16_t dlt_value = DLT_C_HDLC;
- /*
- * 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_hdlc_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_hdlc_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->
- requires
- += 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_hdlc_init;
- plugin->plugin_cleanup = dlt_hdlc_cleanup;
- plugin->plugin_parse_opts = dlt_hdlc_parse_opts;
- plugin->plugin_decode = dlt_hdlc_decode;
- plugin->plugin_encode = dlt_hdlc_encode;
- plugin->plugin_proto = dlt_hdlc_proto;
- plugin->plugin_l2addr_type = dlt_hdlc_l2addr_type;
- plugin->plugin_l2len = dlt_hdlc_l2len;
- plugin->plugin_get_layer3 = dlt_hdlc_get_layer3;
- plugin->plugin_merge_layer3 = dlt_hdlc_merge_layer3;
- plugin->plugin_get_mac = dlt_hdlc_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_hdlc_init(tcpeditdlt_t *ctx)
- {
- tcpeditdlt_plugin_t *plugin;
- hdlc_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 deocde extra data */
- if (ctx->decoded_extra_size > 0) {
- if (ctx->decoded_extra_size < sizeof(hdlc_extra_t)) {
- ctx->decoded_extra_size = sizeof(hdlc_extra_t);
- ctx->decoded_extra = safe_realloc(ctx->decoded_extra, ctx->decoded_extra_size);
- }
- } else {
- ctx->decoded_extra_size = sizeof(hdlc_extra_t);
- ctx->decoded_extra = safe_malloc(ctx->decoded_extra_size);
- }
- /* allocate memory for our config data */
- plugin->config_size = sizeof(hdlc_config_t);
- plugin->config = safe_malloc(plugin->config_size);
- config = (hdlc_config_t *)plugin->config;
- /* default to unset */
- config->address = 65535;
- config->control = 65535;
- 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_hdlc_init(), this is just an stub.
- * Returns: TCPEDIT_ERROR | TCPEDIT_OK | TCPEDIT_WARN
- */
- int
- dlt_hdlc_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_hdlc_parse_opts(tcpeditdlt_t *ctx)
- {
- tcpeditdlt_plugin_t *plugin;
- hdlc_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;
- if (HAVE_OPT(HDLC_CONTROL)) {
- config->control = (uint16_t)OPT_VALUE_HDLC_CONTROL;
- }
- if (HAVE_OPT(HDLC_ADDRESS)) {
- config->address = (uint16_t)OPT_VALUE_HDLC_ADDRESS;
- }
- 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_hdlc_decode(tcpeditdlt_t *ctx, const u_char *packet, int pktlen)
- {
- cisco_hdlc_t *hdlc;
- hdlc_extra_t *extra;
- assert(ctx);
- assert(packet);
- if ((size_t)pktlen < sizeof(*hdlc))
- return TCPEDIT_ERROR;
- if (ctx->decoded_extra_size < sizeof(*extra))
- return TCPEDIT_ERROR;
- extra = (hdlc_extra_t *)ctx->decoded_extra;
- hdlc = (cisco_hdlc_t *)packet;
- ctx->proto = hdlc->protocol;
- ctx->l2len = 4;
- extra->address = hdlc->address;
- extra->control = hdlc->control;
- return TCPEDIT_OK; /* success */
- }
- /*
- * Function to encode the layer 2 header back into the packet.
- * Returns: total packet len or TCPEDIT_ERROR
- */
- int
- dlt_hdlc_encode(tcpeditdlt_t *ctx, u_char *packet, int pktlen, _U_ tcpr_dir_t dir)
- {
- cisco_hdlc_t *hdlc;
- hdlc_config_t *config = NULL;
- hdlc_extra_t *extra = NULL;
- tcpeditdlt_plugin_t *plugin = NULL;
- int newpktlen;
- assert(ctx);
- assert(packet);
- if ((size_t)pktlen < sizeof(*hdlc))
- return TCPEDIT_ERROR;
- if (ctx->decoded_extra_size < sizeof(*extra))
- return TCPEDIT_ERROR;
- /* Make room for our new l2 header if old l2len != 4 */
- if (ctx->l2len > 4) {
- memmove(packet + 4, packet + ctx->l2len, pktlen - ctx->l2len);
- } else if (ctx->l2len < 4) {
- u_char *tmpbuff = safe_malloc(pktlen);
- memcpy(tmpbuff, packet, pktlen);
- memcpy(packet + 4, (tmpbuff + ctx->l2len), pktlen - ctx->l2len);
- safe_free(tmpbuff);
- }
- /* update the total packet length */
- newpktlen = pktlen + 4 - ctx->l2len;
- /*
- * HDLC doesn't support direction, since we have no real src/dst addresses
- * to deal with, so we just use the original packet data or option data
- */
- hdlc = (cisco_hdlc_t *)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;
- extra = (hdlc_extra_t *)ctx->decoded_extra;
- if (ctx->decoded_extra_size < sizeof(*extra))
- return TCPEDIT_ERROR;
- /* set the address field */
- if (config->address < 65535) {
- hdlc->address = (uint8_t)config->address;
- } else if (extra->hdlc) {
- hdlc->address = extra->hdlc;
- } else {
- tcpedit_seterr(ctx->tcpedit, "%s", "Non-HDLC packet requires --hdlc-address");
- return TCPEDIT_ERROR;
- }
- /* set the control field */
- if (config->control < 65535) {
- hdlc->control = (uint8_t)config->control;
- } else if (extra->hdlc) {
- hdlc->control = extra->hdlc;
- } else {
- tcpedit_seterr(ctx->tcpedit, "%s", "Non-HDLC packet requires --hdlc-control");
- return TCPEDIT_ERROR;
- }
- /* copy over our protocol */
- hdlc->protocol = ctx->proto;
- return newpktlen; /* success */
- }
- /*
- * Function returns the Layer 3 protocol type of the given packet, or TCPEDIT_ERROR on error
- */
- int
- dlt_hdlc_proto(tcpeditdlt_t *ctx, const u_char *packet, int pktlen)
- {
- cisco_hdlc_t *hdlc;
- assert(ctx);
- assert(packet);
- if (pktlen < 4)
- return TCPEDIT_ERROR;
- hdlc = (cisco_hdlc_t *)packet;
- return hdlc->protocol;
- }
- /*
- * Function returns a pointer to the layer 3 protocol header or NULL on error
- */
- u_char *
- dlt_hdlc_get_layer3(tcpeditdlt_t *ctx, u_char *packet, int pktlen)
- {
- int l2len;
- assert(ctx);
- assert(packet);
- l2len = dlt_hdlc_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_hdlc_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_hdlc_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 the length of the L2 header of the current packet
- */
- int
- dlt_hdlc_l2len(tcpeditdlt_t *ctx, const u_char *packet, int pktlen)
- {
- assert(ctx);
- assert(packet);
- if (pktlen < 4)
- return -1;
- /* HDLC is a static 4 bytes */
- return 4;
- }
- /*
- * return a static pointer to the source/destination MAC address
- * return NULL on error/address doesn't exist
- */
- u_char *
- dlt_hdlc_get_mac(tcpeditdlt_t *ctx, tcpeditdlt_mac_type_t mac, const u_char *packet, int pktlen)
- {
- assert(ctx);
- assert(packet);
- if (pktlen < 14)
- return NULL;
- /* FIXME: return a ptr to the source or dest mac address. */
- switch (mac) {
- case SRC_MAC:
- return (NULL);
- case DST_MAC:
- memcpy(ctx->dstmac, packet, 2);
- return (ctx->dstmac);
- default:
- errx(-1, "Invalid tcpeditdlt_mac_type_t: %d", mac);
- }
- }
- tcpeditdlt_l2addr_type_t
- dlt_hdlc_l2addr_type(void)
- {
- return C_HDLC;
- }
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