dhcp6.c

/**
 * This file is part of pgen, a packet generator tool.
 * Copyright (C) 2013  Balakumaran Kannan <kumaran.4353@gmail.com>
 *
 * This program 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
 * (at your option) any later version.
 *
 * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "pgen.h"

struct dhcp6_pkt {
	int8_t msg_type;
	/**
	 * Transaction id
	 *
	 * Using structure for transaction id causes extra bytes because of
	 * structure padding.
	 */
	int8_t trans_f_byte;
	int8_t trans_s_byte;
	int8_t trans_t_byte;
	/*
	 * option is a place-holder. User has to be take care of the buff_size
	 */
	int8_t option;
};

int dhcp6_iana_op_writer(FILE *fp, char *op_ptr) {
	char option[MAX_OPTION_LEN], value[MAX_VALUE_LEN];
	int32_t tmp, len = 0, op_num;
	/**
	 * Four items
	 * 1. IAID
	 * 2. T1
	 * 3. T2
	 *
	 * 4. Number of IANA optins
	 */
	int32_t items = 4;

	while (items--) {
		if (pgen_parse_option(fp, option, value))
			goto err;

		if (!strcmp(option, "DHCP6_IANA_IAID")) {
			if (pgen_store_num(&tmp, value))
				goto err;
			tmp = htonl(tmp);
			memcpy(op_ptr, &tmp, 4);
			op_ptr += 4;
			len += 4;
		}
		else if (!strcmp(option, "DHCP6_IANA_T1")) {
			if (pgen_store_num(&tmp, value))
				goto err;
			tmp = htonl(tmp);
			memcpy(op_ptr, &tmp, 4);
			op_ptr += 4;
			len += 4;
		}
		else if (!strcmp(option, "DHCP6_IANA_T2")) {
			if (pgen_store_num(&tmp, value))
				goto err;
			tmp = htonl(tmp);
			memcpy(op_ptr, &tmp, 4);
			op_ptr += 4;
			len += 4;
		}
		else if (!strcmp(option, "DHCP6_IANA_OP_NUM")) {
			if (pgen_store_num(&op_num ,value))
				goto err;
		}
		else
			goto err;
	}

	while (op_num--) {
		/**
		 * I couldn't able to find resources telling about IANA options.
		 * Once found, this section will be completed.
		 */
	}

	return len;

err:
	PGEN_INFO("Error while writing DHCP6_IANA_OPTION");
	PGEN_PRINT_DATA("Option: %s\tValue: %s\n", option, value);
	return -1;
}

int dhcp6_iata_op_writer(FILE *fp, char *op_ptr) {
	char option[MAX_OPTION_LEN], value[MAX_VALUE_LEN];
	int32_t tmp, len = 0, op_num;
	/**
	 * Totoally 2 options
	 * 1. IAID
	 *
	 * 2. Number of options
	 */
	int32_t items = 2;

	while (items--) {
		if (pgen_parse_option(fp, option, value))
			goto err;

		if (!strcmp(option, "DHCP6_IATA_IAID")) {
			if (pgen_store_num(&tmp, value))
				goto err;
			tmp = htonl(tmp);
			memcpy(op_ptr, &tmp, 4);
			op_ptr += 4;
			len += 4;
		}
		else if (!strcmp(option, "DHCP6_IATA_OP_NUM")) {
			if (pgen_store_num(&op_num, value))
				goto err;
		}
		else
			goto err;
	}

	while (op_num--) {
		/**
		 * Options not yet identified
		 */
	}

	return len;

err:
	PGEN_INFO("Error while writing DHCP6 IATA option");
	PGEN_PRINT_DATA("Option: %s\tValue: %s\n", option, value);
	return -1;
}

char* pgen_dhcp6_writer(FILE *fp, char *cp_cur) {
	struct dhcp6_pkt *pkt = (struct dhcp6_pkt *)cp_cur;
	char option[MAX_OPTION_LEN], value[MAX_VALUE_LEN];

	/**
	 * Three items we need for dhcp6 packet.
	 * 1. Message type
	 * 2. Transaction ID
	 *
	 * 3. Number of options
	 */
	int32_t items=3, tmp, op_num, op_len = 0;
	int8_t *op_ptr;
	int16_t sh_tmp;

	while (items--) {
		if (pgen_parse_option(fp, option, value))
			goto err;

		if (!strcmp(option, "DHCP6_MSG_TYPE")) {
			if (pgen_store_num(&tmp, value))
				goto err;

			pkt->msg_type = (int8_t)tmp;
		}
		else if (!strcmp(option, "DHCP6_TRANS_ID")) {
			if (pgen_store_num(&tmp, value))
				goto err;

			pkt->trans_f_byte |= ((tmp >> 16) & 0xff);
			pkt->trans_s_byte |= ((tmp >> 8) & 0xff);
			pkt->trans_t_byte |= (tmp & 0xff);
		}
		else if (!strcmp(option, "DHCP6_OP_NUM")) {
			if (pgen_store_num(&tmp, value))
				goto err;
			op_num = tmp;
		}
	}

	/* Here comes the options */
	op_ptr = &pkt->option;
	while (op_num--) {
		if (pgen_parse_option(fp, option, value))
			goto err;
		if (!strcmp(option, "DHCP6_OP_CODE")) {
			if (pgen_store_num(&tmp, value))
				goto err;
			tmp = htons(tmp);
			memcpy(op_ptr, &tmp, 2);
			op_ptr += 2;
			op_len += 2;
		}
		else
			goto err;

		if (pgen_parse_option(fp, option, value))
			goto err;
		if (!strcmp(option, "DHCP6_OP_LEN")) {
			if (pgen_store_num(&tmp, value))
				goto err;
			tmp = htons(tmp);
			memcpy(op_ptr, &tmp, 2);
			op_ptr += 2;
			op_len += 2;
		}
		else
			goto err;

		if (pgen_parse_option(fp, option, value))
			goto err;
		if (!strcmp(option, "DHCP6_OPTION")) {
			/* Client Identifier option */
			if (!strcmp(value, "DHCP6_CLIENT_ID")) {
				if (pgen_parse_option(fp, option, value))
					goto err;
				if (strcmp(option, "DHCP6_CLIENT_ID"))
					goto err;
				tmp = pgen_hex_dump(op_ptr, value);
				if (tmp < 0)
					goto err;
				op_ptr += tmp;
				op_len += tmp;
			}
			/* Server Identifier Option */
			else if (!strcmp(value, "DHCP6_SERVER_ID")) {
				if (pgen_parse_option(fp, option, value))
					goto err;
				tmp = pgen_hex_dump(op_ptr, value);
				if (tmp < 0)
					goto err;
				op_ptr += tmp;
				op_len += tmp;
			}
			/* Option Request Option */
			else if (!strcmp(value, "DHCP6_ORO")) {
				/**
				 * option-len = 2 * number of requested options [RFC-3315]
				 */
				int32_t orc_num = htons(tmp) / 2;
				while (orc_num) {
					if (pgen_parse_option(fp, option, value))
						goto err;
					if (strcmp(option, "DHCP6_ORC"))
						goto err;
					if (pgen_store_num(&tmp, value)) {
						printf("store num error\n");
						goto err;
					}
					tmp = htons(tmp);
					memcpy(op_ptr, &tmp, 2);
					op_ptr += 2;
					op_len += 2;
					orc_num--;
				}
			}
			/* Option Preference */
			else if (!strcmp(value, "DHCP6_OP_PREF")) {
				if (pgen_parse_option(fp, option, value))
					goto err;
				if (strcmp(option, "DHCP6_OP_PREF"))
					goto err;
				if (pgen_store_num(&tmp, value))
					goto err;
				*op_ptr = (char)tmp;
				op_ptr++;
				op_len++;
			}
			/* Elapsed time option */
			else if (!strcmp(value, "DHCP6_OP_ELAPSED_TIME")) {
				if (pgen_parse_option(fp, option, value))
					goto err;
				if (strcmp(option, "DHCP6_OP_ELAPSED_TIME"))
					goto err;
				if (pgen_store_num(&tmp, value))
					goto err;
				sh_tmp = htons(tmp);
				memcpy(op_ptr, &sh_tmp, 2);
				op_ptr += 2;
				op_len += 2;
			}
			/* Server Unicast Option */
			else if (!strcmp(value, "DHCP6_OP_SERVER_UNICAST")) {
				if (pgen_parse_option(fp, option, value))
					goto err;
				if (strcmp(option, "DHCP6_OP_SER_UNICAST_ADDR"))
					goto err;
				if (ip6_writer((char *)op_ptr, value))
					goto err;
				op_ptr += 16;
				op_len += 16;
			}
			/* IANA Option */
			else if (!strcmp(value, "DHCP6_OPTION_IANA")) {
				tmp = dhcp6_iana_op_writer(fp, (char *)op_ptr);
				if (tmp < 0)
					goto err;
				op_ptr += tmp;
				op_len += tmp;
			}
			/* IATA Option */
			else if (!strcmp(value, "DHCP6_OPTION_IATA")) {
				tmp = dhcp6_iata_op_writer(fp, (char *)op_ptr);
				if (tmp < 0)
					goto err;
				op_ptr += tmp;
				op_len += tmp;
			}
			/* Status Code Option */
			else if (!strcmp(value, "DHCP6_STATUS_CODE")) {
				int16_t st_code;

				if (pgen_parse_option(fp, option, value))
					goto err;
				if (!strcmp(option, "DHCP6_OP_STATUS_CODE")) {
					if (!strcmp(value, "SUCCESS"))
						st_code = htons(0);
					else if (!strcmp(value, "UNSPECFAIL"))
						st_code = htons(1);
					else if (!strcmp(value, "NOADDRAVAIL"))
						st_code = htons(2);
					else if (!strcmp(value, "NOBINDING"))
						st_code = htons(3);
					else if (!strcmp(value, "NOTONLINK"))
						st_code = htons(4);
					else if (!strcmp(value, "USEMULTICAST"))
						st_code = htons(5);
					else {
						if (pgen_store_num(&tmp, value))
							goto err;
						st_code = htons(tmp);
					}
					memcpy(op_ptr, &st_code, 2);
					op_ptr += 2;
					op_len += 2;
				}
				else
					goto err;

				if (pgen_parse_option(fp, option, value))
					goto err;
				if (!strcmp(option, "DHCP6_OP_STATUS_MSG")) {
					tmp = pgen_hex_dump((int8_t *)op_ptr, value);
					if (tmp < 0)
						goto err;
					op_ptr += tmp;
					op_len += tmp;
				}
				else
					goto err;
			}
			/* Rapid Commit Option */
			else if (!strcmp(value, "DHCP6_RAPID_COMMIT")) {
				/* Do nothing */
			}
			/* User Class Option */
			else if (!strcmp(value, "DHCP6_USER_CLASS")) {
				int32_t op_num;

				if (pgen_parse_option(fp, option, value))
					goto err;
				if (!strcmp(option, "DHCP6_OP_USR_CLS_NUM")) {
					if (pgen_store_num(&op_num, value))
						goto err;
				}

				while (op_num--) {
					if (pgen_parse_option(fp, option, value))
						goto err;
					if (strcmp(option, "DHCP6_OP_USR_CLS_LEN"))
						goto err;
					if (pgen_store_num(&tmp, value))
						goto err;
					sh_tmp = htons(tmp);
					memcpy(op_ptr, &sh_tmp, 2);
					op_ptr += 2;
					op_len += 2;

					if (pgen_parse_option(fp, option, value))
						goto err;
					if (strcmp(option, "DHCP6_OP_USR_CLS_DATA"))
						goto err;
					tmp = pgen_hex_dump((int8_t *)op_ptr, value);
					if (tmp < 0)
						goto err;
					op_ptr += tmp;
					op_len += tmp;
				}
			}
			/* Vender Class Option */
			else if (!strcmp(value, "DHCP6_VENDER_CLASS")) {
				int32_t op_num;

				if (pgen_parse_option(fp, option, value))
					goto err;
				if (strcmp(option, "DHCP6_OP_VND_ENT_NO"))
					goto err;
				if (pgen_store_num(&tmp, value))
					goto err;
				tmp = htonl(tmp);
				memcpy(op_ptr, &tmp, 4);
				op_ptr += 4;
				op_len += 4;

				if (pgen_parse_option(fp, option, value))
					goto err;
				if (strcmp(option, "DHCP6_OP_VND_CLS_NUM"))
					goto err;
				if (pgen_store_num(&op_num, value))
					goto err;

				while (op_num--) {
					if (pgen_parse_option(fp, option, value))
						goto err;
					if (strcmp(option, "DHCP6_OP_VND_CLS_LEN"))
						goto err;
					if (pgen_store_num(&tmp, value))
						goto err;
					sh_tmp = htons(tmp);
					memcpy(op_ptr, &sh_tmp, 2);
					op_ptr += 2;
					op_len += 2;

					if (pgen_parse_option(fp, option, value))
						goto err;
					if (strcmp(option, "DHCP6_OP_VND_CLS_DATA"))
						goto err;
					tmp = pgen_hex_dump((int8_t *)op_ptr, value);
					if (tmp < 0)
						goto err;
					op_ptr += tmp;
					op_len += tmp;
				}
			}
			/* Unknown option */
			else {
				PGEN_INFO("Option not yet supported");
				goto err;
			}
		}
		else
			goto err;
	}

	return (cp_cur + sizeof(struct dhcp6_pkt) + op_len - 1);

err:
	PGEN_INFO("Error while writing dhcp6 packet");
	PGEN_PRINT_DATA("%s\t%s\n", option, value);
	return NULL;
}