--- /dev/null
+/******************************************************************************
+ * Copyright (c) 2004, 2008 IBM Corporation
+ * All rights reserved.
+ * This program and the accompanying materials
+ * are made available under the terms of the BSD License
+ * which accompanies this distribution, and is available at
+ * http://www.opensource.org/licenses/bsd-license.php
+ *
+ * Contributors:
+ * IBM Corporation - initial implementation
+ *****************************************************************************/
+
+
+/*>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> ALGORITHMS <<<<<<<<<<<<<<<<<<<<<<<<<<<<<*/
+
+/** \file dhcp.c <pre>
+ * **************** State-transition diagram for DHCP client *************
+ *
+ * +---------+ Note: DHCP-server msg / DHCP-client msg
+ * | INIT |
+ * +---------+
+ * |
+ * | - / Discover
+ * V
+ * +---------+
+ * | SELECT | Timeout
+ * +---------+ |
+ * | |
+ * | Offer / Request |
+ * | |
+ * V V
+ * +---------+ NACK / - ***********
+ * | REQUEST | ----------------> * FAULT *
+ * +---------+ ***********
+ * |
+ * | ACK / - ***********
+ * +----------------------> * SUCCESS *
+ * ***********
+ *
+ * ************************************************************************
+ * </pre> */
+
+
+/*>>>>>>>>>>>>>>>>>>>>> DEFINITIONS & DECLARATIONS <<<<<<<<<<<<<<<<<<<<<<*/
+
+#include <dhcp.h>
+#include <ethernet.h>
+#include <ipv4.h>
+#include <udp.h>
+#include <dns.h>
+
+#include <stdio.h>
+#include <string.h>
+#include <time.h>
+#include <sys/socket.h>
+#include <ctype.h>
+#include <stdlib.h>
+
+/* DHCP Message Types */
+#define DHCPDISCOVER 1
+#define DHCPOFFER 2
+#define DHCPREQUEST 3
+#define DHCPDECLINE 4
+#define DHCPACK 5
+#define DHCPNACK 6
+#define DHCPRELEASE 7
+#define DHCPINFORM 8
+
+/* DHCP Option Codes */
+#define DHCP_MASK 1
+#define DHCP_ROUTER 3
+#define DHCP_DNS 6
+#define DHCP_REQUESTED_IP 50
+#define DHCP_OVERLOAD 52
+#define DHCP_MSG_TYPE 53
+#define DHCP_SERVER_ID 54
+#define DHCP_REQUEST_LIST 55
+#define DHCP_TFTP_SERVER 66
+#define DHCP_BOOTFILE 67
+#define DHCP_CLIENT_ARCH 93
+#define DHCP_ENDOPT 0xFF
+#define DHCP_PADOPT 0x00
+
+/* "file/sname" overload option values */
+#define DHCP_OVERLOAD_FILE 1
+#define DHCP_OVERLOAD_SNAME 2
+#define DHCP_OVERLOAD_BOTH 3
+
+/* DHCP states codes */
+#define DHCP_STATE_SELECT 1
+#define DHCP_STATE_REQUEST 2
+#define DHCP_STATE_SUCCESS 3
+#define DHCP_STATE_FAULT 4
+
+/* DHCP Client Architecture */
+#ifndef DHCPARCH
+#define USE_DHCPARCH 0
+#define DHCPARCH 0
+#else
+#define USE_DHCPARCH 1
+#endif
+
+static uint8_t dhcp_magic[] = {0x63, 0x82, 0x53, 0x63};
+/**< DHCP_magic is a cookie, that identifies DHCP options (see RFC 2132) */
+
+/** \struct dhcp_options_t
+ * This structure is used to fill options in DHCP-msg during transmitting
+ * or to retrieve options from DHCP-msg during receiving.
+ * <p>
+ * If flag[i] == TRUE then field for i-th option retains valid value and
+ * information from this field may retrived (in case of receiving) or will
+ * be transmitted (in case of transmitting).
+ *
+ */
+typedef struct {
+ uint8_t flag[256]; /**< Show if corresponding opt. is valid */
+ uint8_t request_list[256]; /**< o.55 If i-th member is TRUE, then i-th
+ option will be requested from server */
+ uint32_t server_ID; /**< o.54 Identifies DHCP-server */
+ uint32_t requested_IP; /**< o.50 Must be filled in DHCP-Request */
+ uint32_t dns_IP; /**< o. 6 DNS IP */
+ uint32_t router_IP; /**< o. 3 Router IP */
+ uint32_t subnet_mask; /**< o. 1 Subnet mask */
+ uint8_t msg_type; /**< o.53 DHCP-message type */
+ uint8_t overload; /**< o.52 Overload sname/file fields */
+ int8_t tftp_server[256]; /**< o.66 TFTP server name */
+ int8_t bootfile[256]; /**< o.67 Boot file name */
+ uint16_t client_arch; /**< o.93 Client architecture type */
+} dhcp_options_t;
+
+/** Stores state of DHCP-client (refer to State-transition diagram) */
+static uint8_t dhcp_state;
+
+
+/*>>>>>>>>>>>>>>>>>>>>>>>>>>>> PROTOTYPES <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<*/
+
+static int32_t
+dhcp_attempt(int fd);
+
+static int32_t
+dhcp_encode_options(uint8_t * opt_field, dhcp_options_t * opt_struct);
+
+static int32_t
+dhcp_decode_options(uint8_t opt_field[], uint32_t opt_len,
+ dhcp_options_t * opt_struct);
+
+static int8_t
+dhcp_merge_options(uint8_t dst_options[], uint32_t * dst_len,
+ uint8_t src_options[], uint32_t src_len);
+
+static int8_t
+dhcp_find_option(uint8_t options[], uint32_t len,
+ uint8_t op_code, uint32_t * op_offset);
+
+static void
+dhcp_append_option(uint8_t dst_options[], uint32_t * dst_len,
+ uint8_t * new_option);
+
+static void
+dhcp_combine_option(uint8_t dst_options[], uint32_t * dst_len,
+ uint32_t dst_offset, uint8_t * new_option);
+
+static void
+dhcp_send_discover(int fd);
+
+static void
+dhcp_send_request(int fd);
+
+static uint8_t
+strtoip(int8_t * str, uint32_t * ip);
+
+
+/*>>>>>>>>>>>>>>>>>>>>>>>>>>>> LOCAL VARIABLES <<<<<<<<<<<<<<<<<<<<<<<<<<*/
+
+static uint8_t ether_packet[ETH_MTU_SIZE];
+static uint32_t dhcp_own_ip = 0;
+static uint32_t dhcp_server_ip = 0;
+static uint32_t dhcp_siaddr_ip = 0;
+static int8_t dhcp_filename[256];
+static int8_t dhcp_tftp_name[256];
+
+static char * response_buffer;
+
+/*>>>>>>>>>>>>>>>>>>>>>>>>>>>> IMPLEMENTATION <<<<<<<<<<<<<<<<<<<<<<<<<<<*/
+
+int32_t
+dhcpv4(char *ret_buffer, filename_ip_t * fn_ip) {
+
+ uint32_t dhcp_tftp_ip = 0;
+ int fd = fn_ip->fd;
+
+ strcpy((char *) dhcp_filename, "");
+ strcpy((char *) dhcp_tftp_name, "");
+
+ response_buffer = ret_buffer;
+
+ if (dhcp_attempt(fd) == 0)
+ return -1;
+
+ if (fn_ip->own_ip) {
+ dhcp_own_ip = fn_ip->own_ip;
+ }
+ if (fn_ip->server_ip) {
+ dhcp_siaddr_ip = fn_ip->server_ip;
+ }
+ if(fn_ip->filename[0] != 0) {
+ strcpy((char *) dhcp_filename, (char *) fn_ip->filename);
+ }
+
+ // TFTP SERVER
+ if (!strlen((char *) dhcp_tftp_name)) {
+ if (!dhcp_siaddr_ip) {
+ // ERROR: TFTP name is not presented
+ return -3;
+ }
+
+ // take TFTP-ip from siaddr field
+ dhcp_tftp_ip = dhcp_siaddr_ip;
+ }
+ else {
+ // TFTP server defined by its name
+ if (!strtoip(dhcp_tftp_name, &(dhcp_tftp_ip))) {
+ if (!dns_get_ip(fd, dhcp_tftp_name, (uint8_t *)&(dhcp_tftp_ip), 4)) {
+ // DNS error - can't obtain TFTP-server name
+ // Use TFTP-ip from siaddr field, if presented
+ if (dhcp_siaddr_ip) {
+ dhcp_tftp_ip = dhcp_siaddr_ip;
+ }
+ else {
+ // ERROR: Can't obtain TFTP server IP
+ return -4;
+ }
+ }
+ }
+ }
+
+ // Store configuration info into filename_ip strucutre
+ fn_ip -> own_ip = dhcp_own_ip;
+ fn_ip -> server_ip = dhcp_tftp_ip;
+ strcpy((char *) fn_ip -> filename, (char *) dhcp_filename);
+
+ return 0;
+}
+
+/**
+ * DHCP: Tries o obtain DHCP parameters, refer to state-transition diagram
+ */
+static int32_t
+dhcp_attempt(int fd) {
+ int sec;
+
+ // Send DISCOVER message and switch DHCP-client to SELECT state
+ dhcp_send_discover(fd);
+
+ dhcp_state = DHCP_STATE_SELECT;
+
+ // setting up a timer with a timeout of two seconds
+ for (sec = 0; sec < 2; sec++) {
+ set_timer(TICKS_SEC);
+ do {
+ receive_ether(fd);
+
+ // Wait until client will switch to Final state or Timeout occurs
+ switch (dhcp_state) {
+ case DHCP_STATE_SUCCESS :
+ return 1;
+ case DHCP_STATE_FAULT :
+ return 0;
+ }
+ } while (get_timer() > 0);
+ }
+
+ // timeout
+ return 0;
+}
+
+/**
+ * DHCP: Supplements DHCP-message with options stored in structure.
+ * For more information about option coding see dhcp_options_t.
+ *
+ * @param opt_field Points to the "vend" field of DHCP-message
+ * (destination)
+ * @param opt_struct this structure stores info about the options which
+ * will be added to DHCP-message (source)
+ * @return TRUE - options packed;
+ * FALSE - error condition occurs.
+ * @see dhcp_options_t
+ */
+static int32_t
+dhcp_encode_options(uint8_t * opt_field, dhcp_options_t * opt_struct) {
+ uint8_t * options = opt_field;
+ uint16_t i, sum; // used to define is any options set
+
+ // magic
+ memcpy(options, dhcp_magic, 4);
+ options += 4;
+
+ // fill message type
+ switch (opt_struct -> msg_type) {
+ case DHCPDISCOVER :
+ case DHCPREQUEST :
+ case DHCPDECLINE :
+ case DHCPINFORM :
+ case DHCPRELEASE :
+ options[0] = DHCP_MSG_TYPE;
+ options[1] = 1;
+ options[2] = opt_struct -> msg_type;
+ options += 3;
+ break;
+ default :
+ return 0; // Unsupported DHCP-message
+ }
+
+ if (opt_struct -> overload) {
+ options[0] = DHCP_OVERLOAD;
+ options[1] = 0x01;
+ options[2] = opt_struct -> overload;
+ options +=3;
+ }
+
+ if (opt_struct -> flag[DHCP_REQUESTED_IP]) {
+ options[0] = DHCP_REQUESTED_IP;
+ options[1] = 0x04;
+ * (uint32_t *) (options + 2) = htonl (opt_struct -> requested_IP);
+ options +=6;
+ }
+
+ if (opt_struct -> flag[DHCP_SERVER_ID]) {
+ options[0] = DHCP_SERVER_ID;
+ options[1] = 0x04;
+ * (uint32_t *) (options + 2) = htonl (opt_struct -> server_ID);
+ options +=6;
+ }
+
+ sum = 0;
+ for (i = 0; i < 256; i++)
+ sum += opt_struct -> request_list[i];
+
+ if (sum) {
+ options[0] = DHCP_REQUEST_LIST;
+ options[1] = sum;
+ options += 2;
+ for (i = 0; i < 256; i++) {
+ if (opt_struct -> request_list[i]) {
+ options[0] = i; options++;
+ }
+ }
+ }
+
+ if (opt_struct -> flag[DHCP_TFTP_SERVER]) {
+ options[0] = DHCP_TFTP_SERVER;
+ options[1] = strlen((char *) opt_struct -> tftp_server) + 1;
+ memcpy(options + 2, opt_struct -> tftp_server, options[1]);
+ options += options[1] + 2;
+ }
+
+ if (opt_struct -> flag[DHCP_BOOTFILE]) {
+ options[0] = DHCP_BOOTFILE;
+ options[1] = strlen((char *) opt_struct -> bootfile) + 1;
+ memcpy(options + 2, opt_struct -> bootfile, options[1]);
+ options += options[1] + 2;
+ }
+
+ if (opt_struct -> flag[DHCP_CLIENT_ARCH]) {
+ options[0] = DHCP_CLIENT_ARCH;
+ options[1] = 2;
+ options[2] = (DHCPARCH >> 8);
+ options[3] = DHCPARCH & 0xff;
+ options += 4;
+ }
+
+ // end options
+ options[0] = 0xFF;
+ options++;
+
+ return 1;
+}
+
+/**
+ * DHCP: Extracts encoded options from DHCP-message into the structure.
+ * For more information about option coding see dhcp_options_t.
+ *
+ * @param opt_field Points to the "options" field of DHCP-message
+ * (source).
+ * @param opt_len Length of "options" field.
+ * @param opt_struct this structure stores info about the options which
+ * was extracted from DHCP-message (destination).
+ * @return TRUE - options extracted;
+ * FALSE - error condition occurs.
+ * @see dhcp_options_t
+ */
+static int32_t
+dhcp_decode_options(uint8_t opt_field[], uint32_t opt_len,
+ dhcp_options_t * opt_struct) {
+ int32_t offset = 0;
+
+ memset(opt_struct, 0, sizeof(dhcp_options_t));
+
+ // magic
+ if (memcmp(opt_field, dhcp_magic, 4)) {
+ return 0;
+ }
+
+ offset += 4;
+ while (offset < opt_len) {
+ opt_struct -> flag[opt_field[offset]] = 1;
+ switch(opt_field[offset]) {
+ case DHCP_OVERLOAD :
+ opt_struct -> overload = opt_field[offset + 2];
+ offset += 2 + opt_field[offset + 1];
+ break;
+
+ case DHCP_REQUESTED_IP :
+ opt_struct -> requested_IP = htonl(* (uint32_t *) (opt_field + offset + 2));
+ offset += 2 + opt_field[offset + 1];
+ break;
+
+ case DHCP_MASK :
+ opt_struct -> flag[DHCP_MASK] = 1;
+ opt_struct -> subnet_mask = htonl(* (uint32_t *) (opt_field + offset + 2));
+ offset += 2 + opt_field[offset + 1];
+ break;
+
+ case DHCP_DNS :
+ opt_struct -> flag[DHCP_DNS] = 1;
+ opt_struct -> dns_IP = htonl(* (uint32_t *) (opt_field + offset + 2));
+ offset += 2 + opt_field[offset + 1];
+ break;
+
+ case DHCP_ROUTER :
+ opt_struct -> flag[DHCP_ROUTER] = 1;
+ opt_struct -> router_IP = htonl(* (uint32_t *) (opt_field + offset + 2));
+ offset += 2 + opt_field[offset + 1];
+ break;
+
+ case DHCP_MSG_TYPE :
+ if ((opt_field[offset + 2] > 0) && (opt_field[offset + 2] < 9))
+ opt_struct -> msg_type = opt_field[offset + 2];
+ else
+ return 0;
+ offset += 2 + opt_field[offset + 1];
+ break;
+
+ case DHCP_SERVER_ID :
+ opt_struct -> server_ID = htonl(* (uint32_t *) (opt_field + offset + 2));
+ offset += 2 + opt_field[offset + 1];
+ break;
+
+ case DHCP_TFTP_SERVER :
+ memcpy(opt_struct -> tftp_server, opt_field + offset + 2, opt_field[offset + 1]);
+ (opt_struct -> tftp_server)[opt_field[offset + 1]] = 0;
+ offset += 2 + opt_field[offset + 1];
+ break;
+
+ case DHCP_BOOTFILE :
+ memcpy(opt_struct -> bootfile, opt_field + offset + 2, opt_field[offset + 1]);
+ (opt_struct -> bootfile)[opt_field[offset + 1]] = 0;
+ offset += 2 + opt_field[offset + 1];
+ break;
+
+ case DHCP_CLIENT_ARCH :
+ opt_struct -> client_arch = ((opt_field[offset + 2] << 8) & 0xFF00) | (opt_field[offset + 3] & 0xFF);
+ offset += 4;
+ break;
+
+ case DHCP_PADOPT :
+ offset++;
+ break;
+
+ case DHCP_ENDOPT : // End of options
+ return 1;
+
+ default :
+ offset += 2 + opt_field[offset + 1]; // Unsupported opt. - do nothing
+ }
+ }
+ if (offset == opt_len)
+ return 1; // options finished without 0xFF
+
+ return 0;
+}
+
+/**
+ * DHCP: Appends information from source "options" into dest "options".
+ * This function is used to support "file/sname" overloading.
+ *
+ * @param dst_options destanation "options" field
+ * @param dst_len size of dst_options (modified by this function)
+ * @param src_options source "options" field
+ * @param src_len size of src_options
+ * @return TRUE - options merged;
+ * FALSE - error condition occurs.
+ */
+static int8_t dhcp_merge_options(uint8_t dst_options[], uint32_t * dst_len,
+ uint8_t src_options[], uint32_t src_len) {
+ int32_t dst_offset, src_offset = 0;
+
+ // remove ENDOPT if presented
+ if (dhcp_find_option(dst_options, * dst_len, DHCP_ENDOPT, (uint32_t *) &dst_offset))
+ * dst_len = dst_offset;
+
+ while (src_offset < src_len) {
+ switch(src_options[src_offset]) {
+ case DHCP_PADOPT:
+ src_offset++;
+ break;
+ case DHCP_ENDOPT:
+ return 1;
+ default:
+ if (dhcp_find_option(dst_options, * dst_len,
+ src_options[src_offset],
+ (uint32_t *) &dst_offset)) {
+ dhcp_combine_option(dst_options, dst_len,
+ dst_offset,
+ (uint8_t *) src_options +
+ src_offset);
+ }
+ else {
+ dhcp_append_option(dst_options, dst_len, src_options + src_offset);
+ }
+ src_offset += 2 + src_options[src_offset + 1];
+ }
+ }
+
+ if (src_offset == src_len)
+ return 1;
+ return 0;
+}
+
+/**
+ * DHCP: Finds given occurrence of the option with the given code (op_code)
+ * in "options" field of DHCP-message.
+ *
+ * @param options "options" field of DHCP-message
+ * @param len length of the "options" field
+ * @param op_code code of the option to find
+ * @param op_offset SUCCESS - offset to an option occurrence;
+ * FAULT - offset is set to zero.
+ * @return TRUE - option was find;
+ * FALSE - option wasn't find.
+ */
+static int8_t dhcp_find_option(uint8_t options[], uint32_t len,
+ uint8_t op_code, uint32_t * op_offset) {
+ uint32_t srch_offset = 0;
+ * op_offset = 0;
+
+ while (srch_offset < len) {
+ if (options[srch_offset] == op_code) {
+ * op_offset = srch_offset;
+ return 1;
+ }
+ if (options[srch_offset] == DHCP_ENDOPT)
+ return 0;
+
+ if (options[srch_offset] == DHCP_PADOPT)
+ srch_offset++;
+ else
+ srch_offset += 2 + options[srch_offset + 1];
+ }
+ return 0;
+}
+
+/**
+ * DHCP: Appends new option from one list (src) into the tail
+ * of another option list (dst)
+ *
+ * @param dst_options "options" field of DHCP-message
+ * @param dst_len length of the "options" field (modified)
+ * @param new_option points to an option in another list (src)
+ */
+static void
+dhcp_append_option(uint8_t dst_options[], uint32_t * dst_len,
+ uint8_t * new_option) {
+ memcpy(dst_options + ( * dst_len), new_option, 2 + (* (new_option + 1)));
+ * dst_len += 2 + *(new_option + 1);
+}
+
+/**
+ * DHCP: This function is used when options with the same code are
+ * presented in both merged lists. In this case information
+ * about the option from one list (src) is combined (complemented)
+ * with information about the option in another list (dst).
+ *
+ * @param dst_options "options" field of DHCP-message
+ * @param dst_len length of the "options" field (modified)
+ * @param dst_offset offset of the option from beginning of the list
+ * @param new_option points to an option in another list (src)
+ */
+static void
+dhcp_combine_option(uint8_t dst_options[], uint32_t * dst_len,
+ uint32_t dst_offset, uint8_t * new_option) {
+
+ uint8_t tmp_buffer[1024]; // use to provide safe memcpy
+ uint32_t tail_len;
+
+ // move all subsequent options (allocate size for additional info)
+ tail_len = (* dst_len) - dst_offset - 2 - dst_options[dst_offset + 1];
+
+ memcpy(tmp_buffer, dst_options + (* dst_len) - tail_len, tail_len);
+ memcpy(dst_options + (* dst_len) - tail_len + (* (new_option + 1)),
+ tmp_buffer, tail_len);
+
+ // add new_content to option
+ memcpy(dst_options + (* dst_len) - tail_len, new_option + 2,
+ * (new_option + 1));
+ dst_options[dst_offset + 1] += * (new_option + 1);
+
+ // correct dst_len
+ * dst_len += * (new_option + 1);
+}
+
+/**
+ * DHCP: Sends DHCP-Discover message. Looks for DHCP servers.
+ */
+static void
+dhcp_send_discover(int fd) {
+ uint32_t packetsize = sizeof(struct iphdr) +
+ sizeof(struct udphdr) + sizeof(struct btphdr);
+ struct btphdr *btph;
+ dhcp_options_t opt;
+
+ memset(ether_packet, 0, packetsize);
+
+ btph = (struct btphdr *) (ðer_packet[
+ sizeof(struct iphdr) + sizeof(struct udphdr)]);
+
+ btph -> op = 1;
+ btph -> htype = 1;
+ btph -> hlen = 6;
+ memcpy(btph -> chaddr, get_mac_address(), 6);
+
+ memset(&opt, 0, sizeof(dhcp_options_t));
+
+ opt.msg_type = DHCPDISCOVER;
+
+ opt.request_list[DHCP_MASK] = 1;
+ opt.request_list[DHCP_DNS] = 1;
+ opt.request_list[DHCP_ROUTER] = 1;
+ opt.request_list[DHCP_TFTP_SERVER] = 1;
+ opt.request_list[DHCP_BOOTFILE] = 1;
+ opt.request_list[DHCP_CLIENT_ARCH] = USE_DHCPARCH;
+
+ dhcp_encode_options(btph -> vend, &opt);
+
+ fill_udphdr(ðer_packet[sizeof(struct iphdr)],
+ sizeof(struct btphdr) + sizeof(struct udphdr),
+ UDPPORT_BOOTPC, UDPPORT_BOOTPS);
+ fill_iphdr(ether_packet, sizeof(struct btphdr) +
+ sizeof(struct udphdr) + sizeof(struct iphdr),
+ IPTYPE_UDP, dhcp_own_ip, 0xFFFFFFFF);
+
+ send_ipv4(fd, ether_packet, packetsize);
+}
+
+/**
+ * DHCP: Sends DHCP-Request message. Asks for acknowledgment to occupy IP.
+ */
+static void
+dhcp_send_request(int fd) {
+ uint32_t packetsize = sizeof(struct iphdr) +
+ sizeof(struct udphdr) + sizeof(struct btphdr);
+ struct btphdr *btph;
+ dhcp_options_t opt;
+
+ memset(ether_packet, 0, packetsize);
+
+ btph = (struct btphdr *) (ðer_packet[
+ sizeof(struct iphdr) + sizeof(struct udphdr)]);
+
+ btph -> op = 1;
+ btph -> htype = 1;
+ btph -> hlen = 6;
+ memcpy(btph -> chaddr, get_mac_address(), 6);
+
+ memset(&opt, 0, sizeof(dhcp_options_t));
+
+ opt.msg_type = DHCPREQUEST;
+ memcpy(&(opt.requested_IP), &dhcp_own_ip, 4);
+ opt.flag[DHCP_REQUESTED_IP] = 1;
+ memcpy(&(opt.server_ID), &dhcp_server_ip, 4);
+ opt.flag[DHCP_SERVER_ID] = 1;
+
+ opt.request_list[DHCP_MASK] = 1;
+ opt.request_list[DHCP_DNS] = 1;
+ opt.request_list[DHCP_ROUTER] = 1;
+ opt.request_list[DHCP_TFTP_SERVER] = 1;
+ opt.request_list[DHCP_BOOTFILE] = 1;
+ opt.request_list[DHCP_CLIENT_ARCH] = USE_DHCPARCH;
+ opt.flag[DHCP_CLIENT_ARCH] = USE_DHCPARCH;
+
+ dhcp_encode_options(btph -> vend, &opt);
+
+ fill_udphdr(ðer_packet[sizeof(struct iphdr)],
+ sizeof(struct btphdr) + sizeof(struct udphdr),
+ UDPPORT_BOOTPC, UDPPORT_BOOTPS);
+ fill_iphdr(ether_packet, sizeof(struct btphdr) +
+ sizeof(struct udphdr) + sizeof(struct iphdr),
+ IPTYPE_UDP, 0, 0xFFFFFFFF);
+
+ send_ipv4(fd, ether_packet, packetsize);
+}
+
+
+/**
+ * DHCP: Sends DHCP-Release message. Releases occupied IP.
+ */
+void dhcp_send_release(int fd) {
+ uint32_t packetsize = sizeof(struct iphdr) +
+ sizeof(struct udphdr) + sizeof(struct btphdr);
+ struct btphdr *btph;
+ dhcp_options_t opt;
+
+ btph = (struct btphdr *) (ðer_packet[
+ sizeof(struct iphdr) + sizeof(struct udphdr)]);
+
+ memset(ether_packet, 0, packetsize);
+
+ btph -> op = 1;
+ btph -> htype = 1;
+ btph -> hlen = 6;
+ strcpy((char *) btph -> file, "");
+ memcpy(btph -> chaddr, get_mac_address(), 6);
+ btph -> ciaddr = htonl(dhcp_own_ip);
+
+ memset(&opt, 0, sizeof(dhcp_options_t));
+
+ opt.msg_type = DHCPRELEASE;
+ opt.server_ID = dhcp_server_ip;
+ opt.flag[DHCP_SERVER_ID] = 1;
+
+ dhcp_encode_options(btph -> vend, &opt);
+
+ fill_udphdr(ðer_packet[sizeof(struct iphdr)],
+ sizeof(struct btphdr) + sizeof(struct udphdr),
+ UDPPORT_BOOTPC, UDPPORT_BOOTPS);
+ fill_iphdr(ether_packet, sizeof(struct btphdr) +
+ sizeof(struct udphdr) + sizeof(struct iphdr), IPTYPE_UDP,
+ dhcp_own_ip, dhcp_server_ip);
+
+ send_ipv4(fd, ether_packet, packetsize);
+}
+
+/**
+ * DHCP: Handles DHCP-messages according to Receive-handle diagram.
+ * Changes the state of DHCP-client.
+ *
+ * @param fd socket descriptor
+ * @param packet BootP/DHCP-packet to be handled
+ * @param packetsize length of the packet
+ * @return ZERO - packet handled successfully;
+ * NON ZERO - packet was not handled (e.g. bad format)
+ * @see receive_ether
+ * @see btphdr
+ */
+
+int8_t
+handle_dhcp(int fd, uint8_t * packet, int32_t packetsize) {
+ struct btphdr * btph;
+ struct iphdr * iph;
+ dhcp_options_t opt;
+
+ memset(&opt, 0, sizeof(dhcp_options_t));
+ btph = (struct btphdr *) packet;
+ iph = (struct iphdr *) packet - sizeof(struct udphdr) -
+ sizeof(struct iphdr);
+ if (btph -> op != 2)
+ return -1; // it is not Boot Reply
+
+ if (memcmp(btph -> vend, dhcp_magic, 4)) {
+ // It is BootP - RFC 951
+ dhcp_own_ip = htonl(btph -> yiaddr);
+ dhcp_siaddr_ip = htonl(btph -> siaddr);
+ dhcp_server_ip = htonl(iph -> ip_src);
+
+ if (strlen((char *) btph -> sname) && !dhcp_siaddr_ip) {
+ strncpy((char *) dhcp_tftp_name, (char *) btph -> sname,
+ sizeof(btph -> sname));
+ dhcp_tftp_name[sizeof(btph -> sname)] = 0;
+ }
+
+ if (strlen((char *) btph -> file)) {
+ strncpy((char *) dhcp_filename, (char *) btph -> file, sizeof(btph -> file));
+ dhcp_filename[sizeof(btph -> file)] = 0;
+ }
+
+ dhcp_state = DHCP_STATE_SUCCESS;
+ return 0;
+ }
+
+
+ // decode options
+ if (!dhcp_decode_options(btph -> vend, packetsize -
+ sizeof(struct btphdr) + sizeof(btph -> vend),
+ &opt)) {
+ return -1; // can't decode options
+ }
+
+ if (opt.overload) {
+ int16_t decode_res = 0;
+ uint8_t options[1024]; // buffer for merged options
+ uint32_t opt_len;
+
+ // move 1-st part of options from vend field into buffer
+ opt_len = packetsize - sizeof(struct btphdr) +
+ sizeof(btph -> vend) - 4;
+ memcpy(options, btph -> vend, opt_len + 4);
+
+ // add other parts
+ switch (opt.overload) {
+ case DHCP_OVERLOAD_FILE:
+ decode_res = dhcp_merge_options(options + 4, &opt_len,
+ btph -> file,
+ sizeof(btph -> file));
+ break;
+ case DHCP_OVERLOAD_SNAME:
+ decode_res = dhcp_merge_options(options + 4, &opt_len,
+ btph -> sname,
+ sizeof(btph -> sname));
+ break;
+ case DHCP_OVERLOAD_BOTH:
+ decode_res = dhcp_merge_options(options + 4, &opt_len,
+ btph -> file,
+ sizeof(btph -> file));
+ if (!decode_res)
+ break;
+ decode_res = dhcp_merge_options(options + 4, &opt_len,
+ btph -> sname,
+ sizeof(btph -> sname));
+ break;
+ }
+
+ if (!decode_res)
+ return -1; // bad options in sname/file fields
+
+ // decode merged options
+ if (!dhcp_decode_options(options, opt_len + 4, &opt)) {
+ return -1; // can't decode options
+ }
+ }
+
+ if (!opt.msg_type) {
+ // It is BootP with Extensions - RFC 1497
+ // retrieve conf. settings from BootP - reply
+ dhcp_own_ip = htonl(btph -> yiaddr);
+ dhcp_siaddr_ip = htonl(btph -> siaddr);
+ if (strlen((char *) btph -> sname) && !dhcp_siaddr_ip) {
+ strncpy((char *) dhcp_tftp_name, (char *) btph -> sname, sizeof(btph -> sname));
+ dhcp_tftp_name[sizeof(btph -> sname)] = 0;
+ }
+
+ if (strlen((char *) btph -> file)) {
+ strncpy((char *) dhcp_filename, (char *) btph -> file, sizeof(btph -> file));
+ dhcp_filename[sizeof(btph -> file)] = 0;
+ }
+
+ // retrieve DHCP-server IP from IP-header
+ dhcp_server_ip = iph -> htonl(ip_src);
+
+ dhcp_state = DHCP_STATE_SUCCESS;
+ }
+ else {
+ // It is DHCP - RFC 2131 & RFC 2132
+ // opt contains parameters from server
+ switch (dhcp_state) {
+ case DHCP_STATE_SELECT :
+ if (opt.msg_type == DHCPOFFER) {
+ dhcp_own_ip = htonl(btph -> yiaddr);
+ dhcp_server_ip = opt.server_ID;
+ dhcp_send_request(fd);
+ dhcp_state = DHCP_STATE_REQUEST;
+ }
+ return 0;
+ case DHCP_STATE_REQUEST :
+ switch (opt.msg_type) {
+ case DHCPNACK :
+ dhcp_own_ip = 0;
+ dhcp_server_ip = 0;
+ dhcp_state = DHCP_STATE_FAULT;
+ break;
+ case DHCPACK :
+ dhcp_own_ip = htonl(btph -> yiaddr);
+ dhcp_server_ip = opt.server_ID;
+ dhcp_siaddr_ip = htonl(btph -> siaddr);
+ if (opt.flag[DHCP_TFTP_SERVER]) {
+ strcpy((char *) dhcp_tftp_name, (char *) opt.tftp_server);
+ }
+ else {
+ strcpy((char *) dhcp_tftp_name, "");
+ if ((opt.overload != DHCP_OVERLOAD_SNAME &&
+ opt.overload != DHCP_OVERLOAD_BOTH) &&
+ !dhcp_siaddr_ip) {
+ strncpy((char *) dhcp_tftp_name,
+ (char *) btph->sname,
+ sizeof(btph -> sname));
+ dhcp_tftp_name[sizeof(btph->sname)] = 0;
+ }
+ }
+
+ if (opt.flag[DHCP_BOOTFILE]) {
+ strcpy((char *) dhcp_filename, (char *) opt.bootfile);
+ }
+ else {
+ strcpy((char *) dhcp_filename, "");
+ if (opt.overload != DHCP_OVERLOAD_FILE &&
+ opt.overload != DHCP_OVERLOAD_BOTH &&
+ strlen((char *) btph -> file)) {
+ strncpy((char *) dhcp_filename,
+ (char *) btph->file,
+ sizeof(btph->file));
+ dhcp_filename[sizeof(btph -> file)] = 0;
+ }
+ }
+
+ dhcp_state = DHCP_STATE_SUCCESS;
+ break;
+ default:
+ break; // Unused DHCP-message - do nothing
+ }
+ break;
+ default :
+ return -1; // Illegal DHCP-client state
+ }
+ }
+
+ if (dhcp_state == DHCP_STATE_SUCCESS) {
+
+ // initialize network entity with real own_ip
+ // to be able to answer for foreign requests
+ set_ipv4_address(dhcp_own_ip);
+
+ if(response_buffer) {
+ if(packetsize <= 1720)
+ memcpy(response_buffer, packet, packetsize);
+ else
+ memcpy(response_buffer, packet, 1720);
+ }
+
+ /* Subnet mask */
+ if (opt.flag[DHCP_MASK]) {
+ /* Router */
+ if (opt.flag[DHCP_ROUTER]) {
+ set_ipv4_router(opt.router_IP);
+ set_ipv4_netmask(opt.subnet_mask);
+ }
+ }
+
+ /* DNS-server */
+ if (opt.flag[DHCP_DNS]) {
+ dns_init(opt.dns_IP, 0, 4);
+ }
+ }
+
+ return 0;
+}
+
+/**
+ * DHCP: Converts "255.255.255.255" -> 32-bit long IP
+ *
+ * @param str string to be converted
+ * @param ip in case of SUCCESS - 32-bit long IP
+ in case of FAULT - zero
+ * @return TRUE - IP converted successfully;
+ * FALSE - error condition occurs (e.g. bad format)
+ */
+static uint8_t
+strtoip(int8_t * str, uint32_t * ip) {
+ int8_t ** ptr = &str;
+ int16_t i = 0, res, len;
+ char octet[256];
+
+ * ip = 0;
+
+ while (**ptr != 0) {
+ if (i > 3 || !isdigit(**ptr))
+ return 0;
+ if (strstr((char *) * ptr, ".") != NULL) {
+ len = (int16_t) ((int8_t *) strstr((char *) * ptr, ".") -
+ (int8_t *) (* ptr));
+ strncpy(octet, (char *) * ptr, len); octet[len] = 0;
+ * ptr += len;
+ }
+ else {
+ strcpy(octet, (char *) * ptr);
+ * ptr += strlen(octet);
+ }
+ res = strtol(octet, NULL, 10);
+ if ((res > 255) || (res < 0))
+ return 0;
+ * ip = ((* ip) << 8) + res;
+ i++;
+ if (** ptr == '.')
+ (*ptr)++;
+ }
+
+ if (i != 4)
+ return 0;
+ return 1;
+}
Code Review / kvmfornfv.git / blobdiff