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1601 lines
40 KiB
C
1601 lines
40 KiB
C
/* dhcpd.c
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*
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* udhcp DHCP client
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*
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* Russ Dill <Russ.Dill@asu.edu> July 2001
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*
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* Converted to busybox by Glenn McGrath August 2002
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <stdio.h>
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#include <sys/time.h>
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#include <sys/types.h>
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#include <sys/file.h>
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#include <unistd.h>
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#include <getopt.h>
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#include <stdlib.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <signal.h>
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#include <time.h>
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#include <string.h>
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#include <sys/ioctl.h>
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#include <net/if.h>
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#include <errno.h>
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#include <netinet/ip.h>
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#include <netinet/udp.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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#if __GLIBC__ >=2 && __GLIBC_MINOR >= 1
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#include <netpacket/packet.h>
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#include <net/ethernet.h>
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#else
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#include <asm/types.h>
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#include <linux/if_packet.h>
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#include <linux/if_ether.h>
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#endif
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#include "libbb.h"
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static int state;
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static unsigned long requested_ip; /* = 0 */
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static unsigned long server_addr;
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static unsigned long timeout;
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static int packet_num; /* = 0 */
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static int fd_main;
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/* #define DEBUG */
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#define VERSION "0.9.7"
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#define LISTEN_NONE 0
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#define LISTEN_KERNEL 1
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#define LISTEN_RAW 2
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static int listen_mode;
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#define DEFAULT_SCRIPT "/usr/share/udhcpc/default.script"
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#define DHCP_END 0xFF
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#define TYPE_MASK 0x0F
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#define BROADCAST_FLAG 0x8000
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#define SERVER_PORT 67
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#define DHCP_MAGIC 0x63825363
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#define BOOTREQUEST 1
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#define BOOTREPLY 2
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#define ETH_10MB 1
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#define ETH_10MB_LEN 6
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#define OPTION_FIELD 0
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#define FILE_FIELD 1
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#define SNAME_FIELD 2
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#define INIT_SELECTING 0
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#define REQUESTING 1
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#define BOUND 2
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#define RENEWING 3
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#define REBINDING 4
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#define INIT_REBOOT 5
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#define RENEW_REQUESTED 6
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#define RELEASED 7
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#define CLIENT_PORT 68
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#define DHCPDISCOVER 1
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#define DHCPOFFER 2
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#define DHCPREQUEST 3
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#define DHCPDECLINE 4
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#define DHCPACK 5
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#define DHCPNAK 6
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#define DHCPRELEASE 7
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#define DHCPINFORM 8
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/* DHCP option codes (partial list) */
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#define DHCP_PADDING 0x00
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#define DHCP_SUBNET 0x01
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#define DHCP_TIME_OFFSET 0x02
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#define DHCP_ROUTER 0x03
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#define DHCP_TIME_SERVER 0x04
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#define DHCP_NAME_SERVER 0x05
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#define DHCP_DNS_SERVER 0x06
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#define DHCP_LOG_SERVER 0x07
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#define DHCP_COOKIE_SERVER 0x08
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#define DHCP_LPR_SERVER 0x09
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#define DHCP_HOST_NAME 0x0c
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#define DHCP_BOOT_SIZE 0x0d
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#define DHCP_DOMAIN_NAME 0x0f
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#define DHCP_SWAP_SERVER 0x10
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#define DHCP_ROOT_PATH 0x11
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#define DHCP_IP_TTL 0x17
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#define DHCP_MTU 0x1a
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#define DHCP_BROADCAST 0x1c
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#define DHCP_NTP_SERVER 0x2a
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#define DHCP_WINS_SERVER 0x2c
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#define DHCP_REQUESTED_IP 0x32
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#define DHCP_LEASE_TIME 0x33
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#define DHCP_OPTION_OVER 0x34
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#define DHCP_MESSAGE_TYPE 0x35
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#define DHCP_SERVER_ID 0x36
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#define DHCP_PARAM_REQ 0x37
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#define DHCP_MESSAGE 0x38
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#define DHCP_MAX_SIZE 0x39
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#define DHCP_T1 0x3a
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#define DHCP_T2 0x3b
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#define DHCP_VENDOR 0x3c
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#define DHCP_CLIENT_ID 0x3d
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/* miscellaneous defines */
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#define MAC_BCAST_ADDR (unsigned char *) "\xff\xff\xff\xff\xff\xff"
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#define OPT_CODE 0
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#define OPT_LEN 1
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#define OPT_DATA 2
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enum {
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OPTION_IP = 1,
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OPTION_IP_PAIR,
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OPTION_STRING,
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OPTION_BOOLEAN,
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OPTION_U8,
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OPTION_U16,
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OPTION_S16,
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OPTION_U32,
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OPTION_S32
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};
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#define OPTION_REQ 0x10 /* have the client request this option */
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#define OPTION_LIST 0x20 /* There can be a list of 1 or more of these */
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#ifdef SYSLOG
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# define LOG(level, str, args...) do { printf(str, ## args); \
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printf("\n"); \
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syslog(level, str, ## args); } while(0)
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# define OPEN_LOG(name) openlog(name, 0, 0)
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# define CLOSE_LOG() closelog()
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#else
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# define LOG_EMERG "EMERGENCY!"
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# define LOG_ALERT "ALERT!"
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# define LOG_CRIT "critical!"
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# define LOG_WARNING "warning"
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# define LOG_ERR "error"
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# define LOG_INFO "info"
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# define LOG_DEBUG "debug"
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# define LOG(level, str, args...) do { printf("%s, " str "\n", level, ## args); } while(0)
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# define OPEN_LOG(name)
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# define CLOSE_LOG()
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#endif
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#ifdef DEBUG
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# undef DEBUG
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# define DEBUG(level, str, args...) LOG(level, str, ## args)
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# define DEBUGGING
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#else
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# define DEBUG(level, str, args...)
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#endif
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struct dhcpMessage {
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u_int8_t op;
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u_int8_t htype;
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u_int8_t hlen;
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u_int8_t hops;
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u_int32_t xid;
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u_int16_t secs;
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u_int16_t flags;
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u_int32_t ciaddr;
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u_int32_t yiaddr;
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u_int32_t siaddr;
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u_int32_t giaddr;
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u_int8_t chaddr[16];
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u_int8_t sname[64];
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u_int8_t file[128];
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u_int32_t cookie;
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u_int8_t options[308]; /* 312 - cookie */
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};
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struct client_config_t {
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char foreground; /* Do not fork */
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char quit_after_lease; /* Quit after obtaining lease */
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char abort_if_no_lease; /* Abort if no lease */
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char *interface; /* The name of the interface to use */
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char *pidfile; /* Optionally store the process ID */
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char *script; /* User script to run at dhcp events */
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unsigned char *clientid; /* Optional client id to use */
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unsigned char *hostname; /* Optional hostname to use */
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int ifindex; /* Index number of the interface to use */
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unsigned char arp[6]; /* Our arp address */
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};
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struct client_config_t client_config = {
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/* Default options. */
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abort_if_no_lease:0,
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foreground:0,
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quit_after_lease:0,
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interface:"eth0",
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pidfile:NULL,
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script:DEFAULT_SCRIPT,
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clientid:NULL,
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hostname:NULL,
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ifindex:0,
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arp:"\0\0\0\0\0\0", /* appease gcc-3.0 */
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};
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struct dhcp_option {
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char name[10];
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char flags;
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unsigned char code;
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};
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struct udp_dhcp_packet {
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struct iphdr ip;
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struct udphdr udp;
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struct dhcpMessage data;
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};
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static const struct dhcp_option options[] = {
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/* name[10] flags code */
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{"subnet", OPTION_IP | OPTION_REQ, 0x01},
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{"timezone", OPTION_S32, 0x02},
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{"router", OPTION_IP | OPTION_LIST | OPTION_REQ, 0x03},
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{"timesvr", OPTION_IP | OPTION_LIST, 0x04},
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{"namesvr", OPTION_IP | OPTION_LIST, 0x05},
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{"dns", OPTION_IP | OPTION_LIST | OPTION_REQ, 0x06},
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{"logsvr", OPTION_IP | OPTION_LIST, 0x07},
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{"cookiesvr", OPTION_IP | OPTION_LIST, 0x08},
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{"lprsvr", OPTION_IP | OPTION_LIST, 0x09},
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{"hostname", OPTION_STRING | OPTION_REQ, 0x0c},
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{"bootsize", OPTION_U16, 0x0d},
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{"domain", OPTION_STRING | OPTION_REQ, 0x0f},
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{"swapsvr", OPTION_IP, 0x10},
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{"rootpath", OPTION_STRING, 0x11},
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{"ipttl", OPTION_U8, 0x17},
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{"mtu", OPTION_U16, 0x1a},
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{"broadcast", OPTION_IP | OPTION_REQ, 0x1c},
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{"ntpsrv", OPTION_IP | OPTION_LIST, 0x2a},
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{"wins", OPTION_IP | OPTION_LIST, 0x2c},
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{"requestip", OPTION_IP, 0x32},
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{"lease", OPTION_U32, 0x33},
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{"dhcptype", OPTION_U8, 0x35},
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{"serverid", OPTION_IP, 0x36},
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{"message", OPTION_STRING, 0x38},
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{"tftp", OPTION_STRING, 0x42},
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{"bootfile", OPTION_STRING, 0x43},
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{"", 0x00, 0x00}
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};
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/* Lengths of the different option types */
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static const unsigned char option_lengths[] = {
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[OPTION_IP] = 4,
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[OPTION_IP_PAIR] = 8,
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[OPTION_BOOLEAN] = 1,
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[OPTION_STRING] = 1,
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[OPTION_U8] = 1,
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[OPTION_U16] = 2,
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[OPTION_S16] = 2,
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[OPTION_U32] = 4,
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[OPTION_S32] = 4
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};
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/* get a rough idea of how long an option will be (rounding up...) */
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static const unsigned char max_option_length[] = {
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[OPTION_IP] = sizeof("255.255.255.255 "),
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[OPTION_IP_PAIR] = sizeof("255.255.255.255 ") * 2,
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[OPTION_STRING] = 1,
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[OPTION_BOOLEAN] = sizeof("yes "),
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[OPTION_U8] = sizeof("255 "),
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[OPTION_U16] = sizeof("65535 "),
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[OPTION_S16] = sizeof("-32768 "),
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[OPTION_U32] = sizeof("4294967295 "),
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[OPTION_S32] = sizeof("-2147483684 "),
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};
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/* return the position of the 'end' option (no bounds checking) */
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static int end_option(unsigned char *optionptr)
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{
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int i = 0;
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while (optionptr[i] != DHCP_END) {
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if (optionptr[i] == DHCP_PADDING)
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i++;
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else
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i += optionptr[i + OPT_LEN] + 2;
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}
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return i;
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}
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/* add an option string to the options (an option string contains an option code,
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* length, then data) */
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static int add_option_string(unsigned char *optionptr, unsigned char *string)
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{
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int end = end_option(optionptr);
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/* end position + string length + option code/length + end option */
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if (end + string[OPT_LEN] + 2 + 1 >= 308) {
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LOG(LOG_ERR, "Option 0x%02x did not fit into the packet!",
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string[OPT_CODE]);
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return 0;
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}
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DEBUG(LOG_INFO, "adding option 0x%02x", string[OPT_CODE]);
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memcpy(optionptr + end, string, string[OPT_LEN] + 2);
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optionptr[end + string[OPT_LEN] + 2] = DHCP_END;
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return string[OPT_LEN] + 2;
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}
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/* add a one to four byte option to a packet */
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static int add_simple_option(unsigned char *optionptr, unsigned char code,
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u_int32_t data)
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{
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char length = 0;
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int i;
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unsigned char option[2 + 4];
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unsigned char *u8;
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u_int16_t *u16;
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u_int32_t *u32;
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u_int32_t aligned;
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u8 = (unsigned char *) &aligned;
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u16 = (u_int16_t *) & aligned;
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u32 = &aligned;
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for (i = 0; options[i].code; i++)
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if (options[i].code == code) {
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length = option_lengths[options[i].flags & TYPE_MASK];
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}
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if (!length) {
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DEBUG(LOG_ERR, "Could not add option 0x%02x", code);
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return 0;
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}
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option[OPT_CODE] = code;
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option[OPT_LEN] = length;
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switch (length) {
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case 1:
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*u8 = data;
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break;
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case 2:
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*u16 = data;
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break;
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case 4:
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*u32 = data;
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break;
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}
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memcpy(option + 2, &aligned, length);
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return add_option_string(optionptr, option);
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}
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static u_int16_t checksum(void *addr, int count)
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{
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/* Compute Internet Checksum for "count" bytes
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* beginning at location "addr".
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*/
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register int32_t sum = 0;
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u_int16_t *source = (u_int16_t *) addr;
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while (count > 1) {
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/* This is the inner loop */
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sum += *source++;
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count -= 2;
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}
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/* Add left-over byte, if any */
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if (count > 0) {
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sum += *(unsigned char *) source;
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}
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/* Fold 32-bit sum to 16 bits */
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while (sum >> 16) {
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sum = (sum & 0xffff) + (sum >> 16);
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}
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return ~sum;
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}
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/* Constuct a ip/udp header for a packet, and specify the source and dest hardware address */
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static int raw_packet(struct dhcpMessage *payload, u_int32_t source_ip,
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int source_port, u_int32_t dest_ip, int dest_port,
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unsigned char *dest_arp, int ifindex)
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{
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int l_fd;
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int result;
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struct sockaddr_ll dest;
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struct udp_dhcp_packet packet;
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if ((l_fd = socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP))) < 0) {
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DEBUG(LOG_ERR, "socket call failed: %s", strerror(errno));
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return -1;
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}
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memset(&dest, 0, sizeof(dest));
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memset(&packet, 0, sizeof(packet));
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dest.sll_family = AF_PACKET;
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dest.sll_protocol = htons(ETH_P_IP);
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dest.sll_ifindex = ifindex;
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dest.sll_halen = 6;
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memcpy(dest.sll_addr, dest_arp, 6);
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if (bind(l_fd, (struct sockaddr *) &dest, sizeof(struct sockaddr_ll)) < 0) {
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DEBUG(LOG_ERR, "bind call failed: %s", strerror(errno));
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close(l_fd);
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return -1;
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}
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packet.ip.protocol = IPPROTO_UDP;
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packet.ip.saddr = source_ip;
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packet.ip.daddr = dest_ip;
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packet.udp.source = htons(source_port);
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packet.udp.dest = htons(dest_port);
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packet.udp.len = htons(sizeof(packet.udp) + sizeof(struct dhcpMessage)); /* cheat on the psuedo-header */
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packet.ip.tot_len = packet.udp.len;
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memcpy(&(packet.data), payload, sizeof(struct dhcpMessage));
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packet.udp.check = checksum(&packet, sizeof(struct udp_dhcp_packet));
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packet.ip.tot_len = htons(sizeof(struct udp_dhcp_packet));
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packet.ip.ihl = sizeof(packet.ip) >> 2;
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packet.ip.version = IPVERSION;
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packet.ip.ttl = IPDEFTTL;
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packet.ip.check = checksum(&(packet.ip), sizeof(packet.ip));
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result =
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sendto(l_fd, &packet, sizeof(struct udp_dhcp_packet), 0,
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(struct sockaddr *) &dest, sizeof(dest));
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if (result <= 0) {
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DEBUG(LOG_ERR, "write on socket failed: %s", strerror(errno));
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}
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close(l_fd);
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return result;
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}
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/* Let the kernel do all the work for packet generation */
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static int kernel_packet(struct dhcpMessage *payload, u_int32_t source_ip,
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int source_port, u_int32_t dest_ip, int dest_port)
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{
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int n = 1;
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int l_fd, result;
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struct sockaddr_in client;
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if ((l_fd = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0) {
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return -1;
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}
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if (setsockopt(l_fd, SOL_SOCKET, SO_REUSEADDR, (char *) &n, sizeof(n)) ==
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-1) {
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return -1;
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}
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memset(&client, 0, sizeof(client));
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client.sin_family = AF_INET;
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client.sin_port = htons(source_port);
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client.sin_addr.s_addr = source_ip;
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if (bind(l_fd, (struct sockaddr *) &client, sizeof(struct sockaddr)) ==
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-1) {
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return -1;
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}
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memset(&client, 0, sizeof(client));
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client.sin_family = AF_INET;
|
|
client.sin_port = htons(dest_port);
|
|
client.sin_addr.s_addr = dest_ip;
|
|
|
|
if (connect(l_fd, (struct sockaddr *) &client, sizeof(struct sockaddr)) ==
|
|
-1) {
|
|
return -1;
|
|
}
|
|
|
|
result = write(l_fd, payload, sizeof(struct dhcpMessage));
|
|
close(l_fd);
|
|
return result;
|
|
}
|
|
|
|
/* initialize a packet with the proper defaults */
|
|
static void init_packet(struct dhcpMessage *packet, char type)
|
|
{
|
|
struct vendor {
|
|
char vendor, length;
|
|
char str[sizeof("udhcp " VERSION)];
|
|
}
|
|
vendor_id = {
|
|
DHCP_VENDOR, sizeof("udhcp " VERSION) - 1, "udhcp " VERSION};
|
|
|
|
memset(packet, 0, sizeof(struct dhcpMessage));
|
|
switch (type) {
|
|
case DHCPDISCOVER:
|
|
case DHCPREQUEST:
|
|
case DHCPRELEASE:
|
|
case DHCPINFORM:
|
|
packet->op = BOOTREQUEST;
|
|
break;
|
|
case DHCPOFFER:
|
|
case DHCPACK:
|
|
case DHCPNAK:
|
|
packet->op = BOOTREPLY;
|
|
}
|
|
packet->htype = ETH_10MB;
|
|
packet->hlen = ETH_10MB_LEN;
|
|
packet->cookie = htonl(DHCP_MAGIC);
|
|
packet->options[0] = DHCP_END;
|
|
add_simple_option(packet->options, DHCP_MESSAGE_TYPE, type);
|
|
|
|
memcpy(packet->chaddr, client_config.arp, 6);
|
|
add_option_string(packet->options, client_config.clientid);
|
|
if (client_config.hostname) {
|
|
add_option_string(packet->options, client_config.hostname);
|
|
}
|
|
add_option_string(packet->options, (unsigned char *) &vendor_id);
|
|
}
|
|
|
|
|
|
/* Add a paramater request list for stubborn DHCP servers. Pull the data
|
|
* from the struct in options.c. Don't do bounds checking here because it
|
|
* goes towards the head of the packet. */
|
|
static void add_requests(struct dhcpMessage *packet)
|
|
{
|
|
int end = end_option(packet->options);
|
|
int i, len = 0;
|
|
|
|
packet->options[end + OPT_CODE] = DHCP_PARAM_REQ;
|
|
for (i = 0; options[i].code; i++) {
|
|
if (options[i].flags & OPTION_REQ) {
|
|
packet->options[end + OPT_DATA + len++] = options[i].code;
|
|
}
|
|
}
|
|
packet->options[end + OPT_LEN] = len;
|
|
packet->options[end + OPT_DATA + len] = DHCP_END;
|
|
|
|
}
|
|
|
|
/* Broadcast a DHCP discover packet to the network, with an optionally requested IP */
|
|
static inline int send_discover(unsigned long xid, unsigned long requested)
|
|
{
|
|
struct dhcpMessage packet;
|
|
|
|
init_packet(&packet, DHCPDISCOVER);
|
|
packet.xid = xid;
|
|
if (requested) {
|
|
add_simple_option(packet.options, DHCP_REQUESTED_IP, requested);
|
|
}
|
|
add_requests(&packet);
|
|
DEBUG(LOG_DEBUG, "Sending discover...");
|
|
return raw_packet(&packet, INADDR_ANY, CLIENT_PORT, INADDR_BROADCAST,
|
|
SERVER_PORT, MAC_BCAST_ADDR, client_config.ifindex);
|
|
}
|
|
|
|
/* Broadcasts a DHCP request message */
|
|
static inline int send_selecting(unsigned long xid, unsigned long server,
|
|
unsigned long requested)
|
|
{
|
|
struct dhcpMessage packet;
|
|
struct in_addr addr;
|
|
|
|
init_packet(&packet, DHCPREQUEST);
|
|
packet.xid = xid;
|
|
|
|
add_simple_option(packet.options, DHCP_REQUESTED_IP, requested);
|
|
add_simple_option(packet.options, DHCP_SERVER_ID, server);
|
|
|
|
add_requests(&packet);
|
|
addr.s_addr = requested;
|
|
DEBUG(LOG_DEBUG, "Sending select for %s...", inet_ntoa(addr));
|
|
return raw_packet(&packet, INADDR_ANY, CLIENT_PORT, INADDR_BROADCAST,
|
|
SERVER_PORT, MAC_BCAST_ADDR, client_config.ifindex);
|
|
}
|
|
|
|
|
|
/* Unicasts or broadcasts a DHCP renew message */
|
|
static int send_renew(unsigned long xid, unsigned long server,
|
|
unsigned long ciaddr)
|
|
{
|
|
struct dhcpMessage packet;
|
|
|
|
init_packet(&packet, DHCPREQUEST);
|
|
packet.xid = xid;
|
|
packet.ciaddr = ciaddr;
|
|
|
|
add_requests(&packet);
|
|
DEBUG(LOG_DEBUG, "Sending renew...");
|
|
if (server) {
|
|
return kernel_packet(&packet, ciaddr, CLIENT_PORT, server,
|
|
SERVER_PORT);
|
|
}
|
|
return raw_packet(&packet, INADDR_ANY, CLIENT_PORT, INADDR_BROADCAST,
|
|
SERVER_PORT, MAC_BCAST_ADDR, client_config.ifindex);
|
|
}
|
|
|
|
/* Create a random xid */
|
|
static unsigned long random_xid(void)
|
|
{
|
|
static int initialized;
|
|
|
|
if (!initialized) {
|
|
srand(time(0));
|
|
initialized++;
|
|
}
|
|
return rand();
|
|
}
|
|
|
|
/* just a little helper */
|
|
static void change_mode(int new_mode)
|
|
{
|
|
DEBUG(LOG_INFO, "entering %s listen mode",
|
|
new_mode ? (new_mode == 1 ? "kernel" : "raw") : "none");
|
|
close(fd_main);
|
|
fd_main = -1;
|
|
listen_mode = new_mode;
|
|
}
|
|
|
|
|
|
/* SIGUSR1 handler (renew) */
|
|
static void renew_requested(int sig)
|
|
{
|
|
sig = 0;
|
|
LOG(LOG_INFO, "Received SIGUSR1");
|
|
if (state == BOUND || state == RENEWING || state == REBINDING ||
|
|
state == RELEASED) {
|
|
change_mode(LISTEN_KERNEL);
|
|
packet_num = 0;
|
|
state = RENEW_REQUESTED;
|
|
}
|
|
|
|
if (state == RELEASED) {
|
|
change_mode(LISTEN_RAW);
|
|
state = INIT_SELECTING;
|
|
}
|
|
|
|
/* Kill any timeouts because the user wants this to hurry along */
|
|
timeout = 0;
|
|
}
|
|
|
|
/* get an option with bounds checking (warning, not aligned). */
|
|
static unsigned char *get_option(struct dhcpMessage *packet, int code)
|
|
{
|
|
int i, length;
|
|
unsigned char *optionptr;
|
|
int over = 0, done = 0, curr = OPTION_FIELD;
|
|
|
|
optionptr = packet->options;
|
|
i = 0;
|
|
length = 308;
|
|
while (!done) {
|
|
if (i >= length) {
|
|
LOG(LOG_WARNING, "bogus packet, option fields too long.");
|
|
return NULL;
|
|
}
|
|
if (optionptr[i + OPT_CODE] == code) {
|
|
if (i + 1 + optionptr[i + OPT_LEN] >= length) {
|
|
LOG(LOG_WARNING, "bogus packet, option fields too long.");
|
|
return NULL;
|
|
}
|
|
return optionptr + i + 2;
|
|
}
|
|
switch (optionptr[i + OPT_CODE]) {
|
|
case DHCP_PADDING:
|
|
i++;
|
|
break;
|
|
case DHCP_OPTION_OVER:
|
|
if (i + 1 + optionptr[i + OPT_LEN] >= length) {
|
|
LOG(LOG_WARNING, "bogus packet, option fields too long.");
|
|
return NULL;
|
|
}
|
|
over = optionptr[i + 3];
|
|
i += optionptr[OPT_LEN] + 2;
|
|
break;
|
|
case DHCP_END:
|
|
if (curr == OPTION_FIELD && over & FILE_FIELD) {
|
|
optionptr = packet->file;
|
|
i = 0;
|
|
length = 128;
|
|
curr = FILE_FIELD;
|
|
} else if (curr == FILE_FIELD && over & SNAME_FIELD) {
|
|
optionptr = packet->sname;
|
|
i = 0;
|
|
length = 64;
|
|
curr = SNAME_FIELD;
|
|
} else {
|
|
done = 1;
|
|
}
|
|
break;
|
|
default:
|
|
i += optionptr[OPT_LEN + i] + 2;
|
|
}
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
static int sprintip(char *dest, char *pre, unsigned char *ip)
|
|
{
|
|
return sprintf(dest, "%s%d.%d.%d.%d ", pre, ip[0], ip[1], ip[2], ip[3]);
|
|
}
|
|
|
|
|
|
/* Fill dest with the text of option 'option'. */
|
|
static inline void fill_options(char *dest, unsigned char *option,
|
|
const struct dhcp_option *type_p)
|
|
{
|
|
int type, optlen;
|
|
u_int16_t val_u16;
|
|
int16_t val_s16;
|
|
u_int32_t val_u32;
|
|
int32_t val_s32;
|
|
int len = option[OPT_LEN - 2];
|
|
|
|
dest += sprintf(dest, "%s=", type_p->name);
|
|
|
|
type = type_p->flags & TYPE_MASK;
|
|
optlen = option_lengths[type];
|
|
for (;;) {
|
|
switch (type) {
|
|
case OPTION_IP_PAIR:
|
|
dest += sprintip(dest, "", option);
|
|
*(dest++) = '/';
|
|
option += 4;
|
|
optlen = 4;
|
|
case OPTION_IP: /* Works regardless of host byte order. */
|
|
dest += sprintip(dest, "", option);
|
|
break;
|
|
case OPTION_BOOLEAN:
|
|
dest += sprintf(dest, *option ? "yes " : "no ");
|
|
break;
|
|
case OPTION_U8:
|
|
dest += sprintf(dest, "%u ", *option);
|
|
break;
|
|
case OPTION_U16:
|
|
memcpy(&val_u16, option, 2);
|
|
dest += sprintf(dest, "%u ", ntohs(val_u16));
|
|
break;
|
|
case OPTION_S16:
|
|
memcpy(&val_s16, option, 2);
|
|
dest += sprintf(dest, "%d ", ntohs(val_s16));
|
|
break;
|
|
case OPTION_U32:
|
|
memcpy(&val_u32, option, 4);
|
|
dest += sprintf(dest, "%lu ", (unsigned long) ntohl(val_u32));
|
|
break;
|
|
case OPTION_S32:
|
|
memcpy(&val_s32, option, 4);
|
|
dest += sprintf(dest, "%ld ", (long) ntohl(val_s32));
|
|
break;
|
|
case OPTION_STRING:
|
|
memcpy(dest, option, len);
|
|
dest[len] = '\0';
|
|
return; /* Short circuit this case */
|
|
}
|
|
option += optlen;
|
|
len -= optlen;
|
|
if (len <= 0) {
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
static char *find_env(const char *prefix, char *defaultstr)
|
|
{
|
|
extern char **environ;
|
|
char **ptr;
|
|
const int len = strlen(prefix);
|
|
|
|
for (ptr = environ; *ptr != NULL; ptr++) {
|
|
if (strncmp(prefix, *ptr, len) == 0) {
|
|
return *ptr;
|
|
}
|
|
}
|
|
return defaultstr;
|
|
}
|
|
|
|
/* put all the paramaters into an environment */
|
|
static char **fill_envp(struct dhcpMessage *packet)
|
|
{
|
|
/* supported options are easily added here */
|
|
int num_options = 0;
|
|
int i, j;
|
|
char **envp;
|
|
unsigned char *temp;
|
|
char over = 0;
|
|
|
|
if (packet == NULL) {
|
|
num_options = 0;
|
|
} else {
|
|
for (i = 0; options[i].code; i++) {
|
|
if (get_option(packet, options[i].code)) {
|
|
num_options++;
|
|
}
|
|
}
|
|
if (packet->siaddr) {
|
|
num_options++;
|
|
}
|
|
if ((temp = get_option(packet, DHCP_OPTION_OVER))) {
|
|
over = *temp;
|
|
}
|
|
if (!(over & FILE_FIELD) && packet->file[0]) {
|
|
num_options++;
|
|
}
|
|
if (!(over & SNAME_FIELD) && packet->sname[0]) {
|
|
num_options++;
|
|
}
|
|
}
|
|
|
|
envp = xmalloc((num_options + 5) * sizeof(char *));
|
|
envp[0] = xmalloc(sizeof("interface=") + strlen(client_config.interface));
|
|
sprintf(envp[0], "interface=%s", client_config.interface);
|
|
envp[1] = find_env("PATH", "PATH=/bin:/usr/bin:/sbin:/usr/sbin");
|
|
envp[2] = find_env("HOME", "HOME=/");
|
|
|
|
if (packet == NULL) {
|
|
envp[3] = NULL;
|
|
return envp;
|
|
}
|
|
|
|
envp[3] = xmalloc(sizeof("ip=255.255.255.255"));
|
|
sprintip(envp[3], "ip=", (unsigned char *) &packet->yiaddr);
|
|
for (i = 0, j = 4; options[i].code; i++) {
|
|
if ((temp = get_option(packet, options[i].code))) {
|
|
envp[j] =
|
|
xmalloc(max_option_length[(&options[i])->flags & TYPE_MASK] *
|
|
(temp[OPT_LEN - 2] /
|
|
option_lengths[(&options[i])->flags & TYPE_MASK]) +
|
|
strlen((&options[i])->name) + 2);
|
|
fill_options(envp[j], temp, &options[i]);
|
|
j++;
|
|
}
|
|
}
|
|
if (packet->siaddr) {
|
|
envp[j] = xmalloc(sizeof("siaddr=255.255.255.255"));
|
|
sprintip(envp[j++], "siaddr=", (unsigned char *) &packet->yiaddr);
|
|
}
|
|
if (!(over & FILE_FIELD) && packet->file[0]) {
|
|
/* watch out for invalid packets */
|
|
packet->file[sizeof(packet->file) - 1] = '\0';
|
|
envp[j] = xmalloc(sizeof("boot_file=") + strlen(packet->file));
|
|
sprintf(envp[j++], "boot_file=%s", packet->file);
|
|
}
|
|
if (!(over & SNAME_FIELD) && packet->sname[0]) {
|
|
/* watch out for invalid packets */
|
|
packet->sname[sizeof(packet->sname) - 1] = '\0';
|
|
envp[j] = xmalloc(sizeof("sname=") + strlen(packet->sname));
|
|
sprintf(envp[j++], "sname=%s", packet->sname);
|
|
}
|
|
envp[j] = NULL;
|
|
return envp;
|
|
}
|
|
|
|
/* Call a script with a par file and env vars */
|
|
static void run_script(struct dhcpMessage *packet, const char *name)
|
|
{
|
|
int pid;
|
|
char **envp;
|
|
|
|
if (client_config.script == NULL) {
|
|
return;
|
|
}
|
|
|
|
/* call script */
|
|
pid = fork();
|
|
if (pid) {
|
|
waitpid(pid, NULL, 0);
|
|
return;
|
|
} else if (pid == 0) {
|
|
envp = fill_envp(packet);
|
|
|
|
/* close fd's? */
|
|
|
|
/* exec script */
|
|
DEBUG(LOG_INFO, "execle'ing %s", client_config.script);
|
|
execle(client_config.script, client_config.script, name, NULL, envp);
|
|
LOG(LOG_ERR, "script %s failed: %s",
|
|
client_config.script, strerror(errno));
|
|
exit(1);
|
|
}
|
|
}
|
|
|
|
/* SIGUSR2 handler (release) */
|
|
static void release_requested(int sig)
|
|
{
|
|
sig = 0;
|
|
LOG(LOG_INFO, "Received SIGUSR2");
|
|
/* send release packet */
|
|
if (state == BOUND || state == RENEWING || state == REBINDING) {
|
|
struct dhcpMessage packet;
|
|
|
|
init_packet(&packet, DHCPRELEASE);
|
|
packet.xid = random_xid();
|
|
packet.ciaddr = requested_ip;
|
|
|
|
add_simple_option(packet.options, DHCP_REQUESTED_IP, requested_ip);
|
|
add_simple_option(packet.options, DHCP_SERVER_ID, server_addr);
|
|
|
|
DEBUG(LOG_DEBUG, "Sending release...");
|
|
kernel_packet(&packet, requested_ip, CLIENT_PORT, server_addr,
|
|
SERVER_PORT);
|
|
run_script(NULL, "deconfig");
|
|
}
|
|
|
|
change_mode(LISTEN_NONE);
|
|
state = RELEASED;
|
|
timeout = 0x7fffffff;
|
|
}
|
|
|
|
|
|
static int pidfile_acquire(char *pidfile)
|
|
{
|
|
int pid_fd;
|
|
|
|
if (pidfile == NULL) {
|
|
return -1;
|
|
}
|
|
pid_fd = open(pidfile, O_CREAT | O_WRONLY, 0644);
|
|
if (pid_fd < 0) {
|
|
LOG(LOG_ERR, "Unable to open pidfile %s: %s\n",
|
|
pidfile, strerror(errno));
|
|
} else {
|
|
lockf(pid_fd, F_LOCK, 0);
|
|
}
|
|
|
|
return pid_fd;
|
|
}
|
|
|
|
|
|
static void pidfile_write_release(int pid_fd)
|
|
{
|
|
FILE *out;
|
|
|
|
if (pid_fd < 0) {
|
|
return;
|
|
}
|
|
if ((out = fdopen(pid_fd, "w")) != NULL) {
|
|
fprintf(out, "%d\n", getpid());
|
|
fclose(out);
|
|
}
|
|
lockf(pid_fd, F_UNLCK, 0);
|
|
close(pid_fd);
|
|
}
|
|
|
|
/* Exit and cleanup */
|
|
static void exit_client(int retval)
|
|
{
|
|
unlink(client_config.pidfile);
|
|
if (client_config.pidfile) {
|
|
unlink(client_config.pidfile);
|
|
}
|
|
CLOSE_LOG();
|
|
exit(retval);
|
|
}
|
|
|
|
|
|
/* SIGTERM handler */
|
|
static void terminate(int sig)
|
|
{
|
|
sig = 0;
|
|
LOG(LOG_INFO, "Received SIGTERM");
|
|
exit_client(0);
|
|
}
|
|
|
|
|
|
static inline int read_interface(char *interface, int *ifindex,
|
|
u_int32_t * addr, unsigned char *arp)
|
|
{
|
|
int l_fd;
|
|
struct ifreq ifr;
|
|
struct sockaddr_in *s_in;
|
|
|
|
memset(&ifr, 0, sizeof(struct ifreq));
|
|
if ((l_fd = socket(AF_INET, SOCK_RAW, IPPROTO_RAW)) >= 0) {
|
|
ifr.ifr_addr.sa_family = AF_INET;
|
|
strcpy(ifr.ifr_name, interface);
|
|
|
|
if (addr) {
|
|
if (ioctl(l_fd, SIOCGIFADDR, &ifr) == 0) {
|
|
s_in = (struct sockaddr_in *) &ifr.ifr_addr;
|
|
*addr = s_in->sin_addr.s_addr;
|
|
DEBUG(LOG_INFO, "%s (our ip) = %s", ifr.ifr_name,
|
|
inet_ntoa(s_in->sin_addr));
|
|
} else {
|
|
LOG(LOG_ERR, "SIOCGIFADDR failed!: %s", strerror(errno));
|
|
return -1;
|
|
}
|
|
}
|
|
|
|
if (ioctl(l_fd, SIOCGIFINDEX, &ifr) == 0) {
|
|
DEBUG(LOG_INFO, "adapter index %d", ifr.ifr_ifindex);
|
|
*ifindex = ifr.ifr_ifindex;
|
|
} else {
|
|
LOG(LOG_ERR, "SIOCGIFINDEX failed!: %s", strerror(errno));
|
|
return -1;
|
|
}
|
|
if (ioctl(l_fd, SIOCGIFHWADDR, &ifr) == 0) {
|
|
memcpy(arp, ifr.ifr_hwaddr.sa_data, 6);
|
|
DEBUG(LOG_INFO,
|
|
"adapter hardware address %02x:%02x:%02x:%02x:%02x:%02x",
|
|
arp[0], arp[1], arp[2], arp[3], arp[4], arp[5]);
|
|
} else {
|
|
LOG(LOG_ERR, "SIOCGIFHWADDR failed!: %s", strerror(errno));
|
|
return -1;
|
|
}
|
|
} else {
|
|
LOG(LOG_ERR, "socket failed!: %s", strerror(errno));
|
|
return -1;
|
|
}
|
|
close(l_fd);
|
|
return 0;
|
|
}
|
|
|
|
|
|
static inline int listen_socket(unsigned int ip, int port, char *inf)
|
|
{
|
|
struct ifreq interface;
|
|
int l_fd;
|
|
struct sockaddr_in addr;
|
|
int n = 1;
|
|
|
|
DEBUG(LOG_INFO, "Opening listen socket on 0x%08x:%d %s\n", ip, port, inf);
|
|
if ((l_fd = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0) {
|
|
DEBUG(LOG_ERR, "socket call failed: %s", strerror(errno));
|
|
return -1;
|
|
}
|
|
|
|
memset(&addr, 0, sizeof(addr));
|
|
addr.sin_family = AF_INET;
|
|
addr.sin_port = htons(port);
|
|
addr.sin_addr.s_addr = ip;
|
|
|
|
if (setsockopt(l_fd, SOL_SOCKET, SO_REUSEADDR, (char *) &n, sizeof(n)) ==
|
|
-1) {
|
|
close(l_fd);
|
|
return -1;
|
|
}
|
|
if (setsockopt(l_fd, SOL_SOCKET, SO_BROADCAST, (char *) &n, sizeof(n)) ==
|
|
-1) {
|
|
close(l_fd);
|
|
return -1;
|
|
}
|
|
|
|
strncpy(interface.ifr_ifrn.ifrn_name, inf, IFNAMSIZ);
|
|
if (setsockopt
|
|
(l_fd, SOL_SOCKET, SO_BINDTODEVICE, (char *) &interface,
|
|
sizeof(interface)) < 0) {
|
|
close(l_fd);
|
|
return -1;
|
|
}
|
|
|
|
if (bind(l_fd, (struct sockaddr *) &addr, sizeof(struct sockaddr)) == -1) {
|
|
close(l_fd);
|
|
return -1;
|
|
}
|
|
|
|
return l_fd;
|
|
}
|
|
|
|
|
|
static int raw_socket(int ifindex)
|
|
{
|
|
int l_fd;
|
|
struct sockaddr_ll sock;
|
|
|
|
DEBUG(LOG_INFO, "Opening raw socket on ifindex %d\n", ifindex);
|
|
if ((l_fd = socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP))) < 0) {
|
|
DEBUG(LOG_ERR, "socket call failed: %s", strerror(errno));
|
|
return -1;
|
|
}
|
|
|
|
sock.sll_family = AF_PACKET;
|
|
sock.sll_protocol = htons(ETH_P_IP);
|
|
sock.sll_ifindex = ifindex;
|
|
if (bind(l_fd, (struct sockaddr *) &sock, sizeof(sock)) < 0) {
|
|
DEBUG(LOG_ERR, "bind call failed: %s", strerror(errno));
|
|
close(l_fd);
|
|
return -1;
|
|
}
|
|
|
|
return l_fd;
|
|
|
|
}
|
|
|
|
/* read a packet from socket fd, return -1 on read error, -2 on packet error */
|
|
static int get_packet(struct dhcpMessage *packet, int l_fd)
|
|
{
|
|
int bytes;
|
|
int i;
|
|
const char broken_vendors[][8] = {
|
|
"MSFT 98",
|
|
""
|
|
};
|
|
char unsigned *vendor;
|
|
|
|
memset(packet, 0, sizeof(struct dhcpMessage));
|
|
bytes = read(l_fd, packet, sizeof(struct dhcpMessage));
|
|
if (bytes < 0) {
|
|
DEBUG(LOG_INFO, "couldn't read on listening socket, ignoring");
|
|
return -1;
|
|
}
|
|
|
|
if (ntohl(packet->cookie) != DHCP_MAGIC) {
|
|
LOG(LOG_ERR, "received bogus message, ignoring");
|
|
return -2;
|
|
}
|
|
DEBUG(LOG_INFO, "Received a packet");
|
|
|
|
if (packet->op == BOOTREQUEST
|
|
&& (vendor = get_option(packet, DHCP_VENDOR))) {
|
|
for (i = 0; broken_vendors[i][0]; i++) {
|
|
if (vendor[OPT_LEN - 2] ==
|
|
(unsigned char) strlen(broken_vendors[i])
|
|
&& !strncmp(vendor, broken_vendors[i], vendor[OPT_LEN - 2])) {
|
|
DEBUG(LOG_INFO, "broken client (%s), forcing broadcast",
|
|
broken_vendors[i]);
|
|
packet->flags |= htons(BROADCAST_FLAG);
|
|
}
|
|
}
|
|
}
|
|
|
|
return bytes;
|
|
}
|
|
|
|
static inline int get_raw_packet(struct dhcpMessage *payload, int l_fd)
|
|
{
|
|
int bytes;
|
|
struct udp_dhcp_packet packet;
|
|
u_int32_t source, dest;
|
|
u_int16_t check;
|
|
|
|
memset(&packet, 0, sizeof(struct udp_dhcp_packet));
|
|
bytes = read(l_fd, &packet, sizeof(struct udp_dhcp_packet));
|
|
if (bytes < 0) {
|
|
DEBUG(LOG_INFO, "couldn't read on raw listening socket -- ignoring");
|
|
usleep(500000); /* possible down interface, looping condition */
|
|
return -1;
|
|
}
|
|
|
|
if (bytes < (int) (sizeof(struct iphdr) + sizeof(struct udphdr))) {
|
|
DEBUG(LOG_INFO, "message too short, ignoring");
|
|
return -1;
|
|
}
|
|
|
|
if (bytes < ntohs(packet.ip.tot_len)) {
|
|
DEBUG(LOG_INFO, "Truncated packet");
|
|
return -1;
|
|
}
|
|
|
|
/* ignore any extra garbage bytes */
|
|
bytes = ntohs(packet.ip.tot_len);
|
|
|
|
/* Make sure its the right packet for us, and that it passes sanity checks */
|
|
if (packet.ip.protocol != IPPROTO_UDP || packet.ip.version != IPVERSION ||
|
|
packet.ip.ihl != sizeof(packet.ip) >> 2
|
|
|| packet.udp.dest != htons(CLIENT_PORT)
|
|
|| bytes > (int) sizeof(struct udp_dhcp_packet)
|
|
|| ntohs(packet.udp.len) != (short) (bytes - sizeof(packet.ip))) {
|
|
DEBUG(LOG_INFO, "unrelated/bogus packet");
|
|
return -1;
|
|
}
|
|
|
|
/* check IP checksum */
|
|
check = packet.ip.check;
|
|
packet.ip.check = 0;
|
|
if (check != checksum(&(packet.ip), sizeof(packet.ip))) {
|
|
DEBUG(LOG_INFO, "bad IP header checksum, ignoring");
|
|
return -1;
|
|
}
|
|
|
|
/* verify the UDP checksum by replacing the header with a psuedo header */
|
|
source = packet.ip.saddr;
|
|
dest = packet.ip.daddr;
|
|
check = packet.udp.check;
|
|
packet.udp.check = 0;
|
|
memset(&packet.ip, 0, sizeof(packet.ip));
|
|
|
|
packet.ip.protocol = IPPROTO_UDP;
|
|
packet.ip.saddr = source;
|
|
packet.ip.daddr = dest;
|
|
packet.ip.tot_len = packet.udp.len; /* cheat on the psuedo-header */
|
|
if (check && check != checksum(&packet, bytes)) {
|
|
DEBUG(LOG_ERR, "packet with bad UDP checksum received, ignoring");
|
|
return -1;
|
|
}
|
|
|
|
memcpy(payload, &(packet.data),
|
|
bytes - (sizeof(packet.ip) + sizeof(packet.udp)));
|
|
|
|
if (ntohl(payload->cookie) != DHCP_MAGIC) {
|
|
LOG(LOG_ERR, "received bogus message (bad magic) -- ignoring");
|
|
return -1;
|
|
}
|
|
DEBUG(LOG_INFO, "oooooh!!! got some!");
|
|
return bytes - (sizeof(packet.ip) + sizeof(packet.udp));
|
|
}
|
|
|
|
|
|
int udhcpc_main(int argc, char *argv[])
|
|
{
|
|
unsigned char *temp, *message;
|
|
unsigned long t1 = 0, t2 = 0, xid = 0;
|
|
unsigned long start = 0, lease;
|
|
fd_set rfds;
|
|
int retval;
|
|
struct timeval tv;
|
|
int c, len;
|
|
struct dhcpMessage packet;
|
|
struct in_addr temp_addr;
|
|
int pid_fd;
|
|
time_t now;
|
|
|
|
static struct option l_options[] = {
|
|
{"clientid", required_argument, 0, 'c'},
|
|
{"foreground", no_argument, 0, 'f'},
|
|
{"hostname", required_argument, 0, 'H'},
|
|
{"help", no_argument, 0, 'h'},
|
|
{"interface", required_argument, 0, 'i'},
|
|
{"now", no_argument, 0, 'n'},
|
|
{"pidfile", required_argument, 0, 'p'},
|
|
{"quit", no_argument, 0, 'q'},
|
|
{"request", required_argument, 0, 'r'},
|
|
{"script", required_argument, 0, 's'},
|
|
{"version", no_argument, 0, 'v'},
|
|
{0, 0, 0, 0}
|
|
};
|
|
|
|
/* get options */
|
|
while (1) {
|
|
int option_index = 0;
|
|
|
|
c = getopt_long(argc, argv, "c:fH:hi:np:qr:s:v", l_options,
|
|
&option_index);
|
|
if (c == -1) {
|
|
break;
|
|
}
|
|
|
|
switch (c) {
|
|
case 'c':
|
|
len = strlen(optarg);
|
|
if (len > 255) {
|
|
len = 255;
|
|
}
|
|
if (client_config.clientid) {
|
|
free(client_config.clientid);
|
|
}
|
|
client_config.clientid = xmalloc(len + 2);
|
|
client_config.clientid[OPT_CODE] = DHCP_CLIENT_ID;
|
|
client_config.clientid[OPT_LEN] = len;
|
|
client_config.clientid[OPT_DATA] = '\0';
|
|
strncpy(client_config.clientid + 3, optarg, len - 1);
|
|
break;
|
|
case 'f':
|
|
client_config.foreground = 1;
|
|
break;
|
|
case 'H':
|
|
len = strlen(optarg);
|
|
if (len > 255) {
|
|
len = 255;
|
|
}
|
|
if (client_config.hostname) {
|
|
free(client_config.hostname);
|
|
}
|
|
client_config.hostname = xmalloc(len + 2);
|
|
client_config.hostname[OPT_CODE] = DHCP_HOST_NAME;
|
|
client_config.hostname[OPT_LEN] = len;
|
|
strncpy(client_config.hostname + 2, optarg, len);
|
|
break;
|
|
case 'h':
|
|
puts("Usage: udhcpcd [OPTIONS]\n\n"
|
|
" -c, --clientid=CLIENTID Client identifier\n"
|
|
" -H, --hostname=HOSTNAME Client hostname\n"
|
|
" -f, --foreground Do not fork after getting lease\n"
|
|
" -i, --interface=INTERFACE Interface to use (default: eth0)\n"
|
|
" -n, --now Exit with failure if lease cannot be\n"
|
|
" immediately negotiated.\n"
|
|
" -p, --pidfile=file Store process ID of daemon in file\n"
|
|
" -q, --quit Quit after obtaining lease\n"
|
|
" -r, --request=IP IP address to request (default: none)\n"
|
|
" -s, --script=file Run file at dhcp events (default:\n"
|
|
" " DEFAULT_SCRIPT ")\n"
|
|
" -v, --version Display version");
|
|
return 0;
|
|
case 'i':
|
|
client_config.interface = optarg;
|
|
break;
|
|
case 'n':
|
|
client_config.abort_if_no_lease = 1;
|
|
break;
|
|
case 'p':
|
|
client_config.pidfile = optarg;
|
|
break;
|
|
case 'q':
|
|
client_config.quit_after_lease = 1;
|
|
break;
|
|
case 'r':
|
|
requested_ip = inet_addr(optarg);
|
|
break;
|
|
case 's':
|
|
client_config.script = optarg;
|
|
break;
|
|
case 'v':
|
|
printf("udhcpcd, version %s\n\n", VERSION);
|
|
exit_client(0);
|
|
break;
|
|
}
|
|
}
|
|
|
|
OPEN_LOG("udhcpc");
|
|
LOG(LOG_INFO, "udhcp client (v%s) started", VERSION);
|
|
|
|
pid_fd = pidfile_acquire(client_config.pidfile);
|
|
pidfile_write_release(pid_fd);
|
|
|
|
if (read_interface
|
|
(client_config.interface, &client_config.ifindex, NULL,
|
|
client_config.arp) < 0) {
|
|
exit_client(1);
|
|
}
|
|
|
|
if (!client_config.clientid) {
|
|
client_config.clientid = xmalloc(6 + 3);
|
|
client_config.clientid[OPT_CODE] = DHCP_CLIENT_ID;
|
|
client_config.clientid[OPT_LEN] = 7;
|
|
client_config.clientid[OPT_DATA] = 1;
|
|
memcpy(client_config.clientid + 3, client_config.arp, 6);
|
|
}
|
|
|
|
/* setup signal handlers */
|
|
signal(SIGUSR1, renew_requested);
|
|
signal(SIGUSR2, release_requested);
|
|
signal(SIGTERM, terminate);
|
|
|
|
state = INIT_SELECTING;
|
|
run_script(NULL, "deconfig");
|
|
change_mode(LISTEN_RAW);
|
|
|
|
for (;;) {
|
|
tv.tv_sec = timeout - time(0);
|
|
tv.tv_usec = 0;
|
|
FD_ZERO(&rfds);
|
|
|
|
if (listen_mode != LISTEN_NONE && fd_main < 0) {
|
|
if (listen_mode == LISTEN_KERNEL) {
|
|
fd_main =
|
|
listen_socket(INADDR_ANY, CLIENT_PORT,
|
|
client_config.interface);
|
|
} else {
|
|
fd_main = raw_socket(client_config.ifindex);
|
|
}
|
|
if (fd_main < 0) {
|
|
LOG(LOG_ERR, "FATAL: couldn't listen on socket, %s",
|
|
strerror(errno));
|
|
exit_client(0);
|
|
}
|
|
}
|
|
if (fd_main >= 0) {
|
|
FD_SET(fd_main, &rfds);
|
|
}
|
|
|
|
if (tv.tv_sec > 0) {
|
|
DEBUG(LOG_INFO, "Waiting on select...\n");
|
|
retval = select(fd_main + 1, &rfds, NULL, NULL, &tv);
|
|
} else {
|
|
retval = 0; /* If we already timed out, fall through */
|
|
}
|
|
|
|
now = time(0);
|
|
if (retval == 0) {
|
|
/* timeout dropped to zero */
|
|
switch (state) {
|
|
case INIT_SELECTING:
|
|
if (packet_num < 3) {
|
|
if (packet_num == 0) {
|
|
xid = random_xid();
|
|
}
|
|
/* send discover packet */
|
|
send_discover(xid, requested_ip); /* broadcast */
|
|
|
|
timeout = now + ((packet_num == 2) ? 10 : 2);
|
|
packet_num++;
|
|
} else {
|
|
if (client_config.abort_if_no_lease) {
|
|
LOG(LOG_INFO, "No lease, failing.");
|
|
exit_client(1);
|
|
}
|
|
/* wait to try again */
|
|
packet_num = 0;
|
|
timeout = now + 60;
|
|
}
|
|
break;
|
|
case RENEW_REQUESTED:
|
|
case REQUESTING:
|
|
if (packet_num < 3) {
|
|
/* send request packet */
|
|
if (state == RENEW_REQUESTED) {
|
|
send_renew(xid, server_addr, requested_ip); /* unicast */
|
|
} else {
|
|
send_selecting(xid, server_addr, requested_ip); /* broadcast */
|
|
}
|
|
timeout = now + ((packet_num == 2) ? 10 : 2);
|
|
packet_num++;
|
|
} else {
|
|
/* timed out, go back to init state */
|
|
state = INIT_SELECTING;
|
|
timeout = now;
|
|
packet_num = 0;
|
|
change_mode(LISTEN_RAW);
|
|
}
|
|
break;
|
|
case BOUND:
|
|
/* Lease is starting to run out, time to enter renewing state */
|
|
state = RENEWING;
|
|
change_mode(LISTEN_KERNEL);
|
|
DEBUG(LOG_INFO, "Entering renew state");
|
|
/* fall right through */
|
|
case RENEWING:
|
|
/* Either set a new T1, or enter REBINDING state */
|
|
if ((t2 - t1) <= (lease / 14400 + 1)) {
|
|
/* timed out, enter rebinding state */
|
|
state = REBINDING;
|
|
timeout = now + (t2 - t1);
|
|
DEBUG(LOG_INFO, "Entering rebinding state");
|
|
} else {
|
|
/* send a request packet */
|
|
send_renew(xid, server_addr, requested_ip); /* unicast */
|
|
|
|
t1 = (t2 - t1) / 2 + t1;
|
|
timeout = t1 + start;
|
|
}
|
|
break;
|
|
case REBINDING:
|
|
/* Either set a new T2, or enter INIT state */
|
|
if ((lease - t2) <= (lease / 14400 + 1)) {
|
|
/* timed out, enter init state */
|
|
state = INIT_SELECTING;
|
|
LOG(LOG_INFO, "Lease lost, entering init state");
|
|
run_script(NULL, "deconfig");
|
|
timeout = now;
|
|
packet_num = 0;
|
|
change_mode(LISTEN_RAW);
|
|
} else {
|
|
/* send a request packet */
|
|
send_renew(xid, 0, requested_ip); /* broadcast */
|
|
|
|
t2 = (lease - t2) / 2 + t2;
|
|
timeout = t2 + start;
|
|
}
|
|
break;
|
|
case RELEASED:
|
|
/* yah, I know, *you* say it would never happen */
|
|
timeout = 0x7fffffff;
|
|
break;
|
|
}
|
|
} else if (retval > 0 && listen_mode != LISTEN_NONE
|
|
&& FD_ISSET(fd_main, &rfds)) {
|
|
/* a packet is ready, read it */
|
|
|
|
if (listen_mode == LISTEN_KERNEL) {
|
|
len = get_packet(&packet, fd_main);
|
|
} else {
|
|
len = get_raw_packet(&packet, fd_main);
|
|
}
|
|
if (len == -1 && errno != EINTR) {
|
|
DEBUG(LOG_INFO, "error on read, %s, reopening socket",
|
|
strerror(errno));
|
|
change_mode(listen_mode); /* just close and reopen */
|
|
}
|
|
if (len < 0) {
|
|
continue;
|
|
}
|
|
|
|
if (packet.xid != xid) {
|
|
DEBUG(LOG_INFO, "Ignoring XID %lx (our xid is %lx)",
|
|
(unsigned long) packet.xid, xid);
|
|
continue;
|
|
}
|
|
|
|
if ((message = get_option(&packet, DHCP_MESSAGE_TYPE)) == NULL) {
|
|
DEBUG(LOG_ERR, "couldnt get option from packet -- ignoring");
|
|
continue;
|
|
}
|
|
|
|
switch (state) {
|
|
case INIT_SELECTING:
|
|
/* Must be a DHCPOFFER to one of our xid's */
|
|
if (*message == DHCPOFFER) {
|
|
if ((temp = get_option(&packet, DHCP_SERVER_ID))) {
|
|
memcpy(&server_addr, temp, 4);
|
|
xid = packet.xid;
|
|
requested_ip = packet.yiaddr;
|
|
|
|
/* enter requesting state */
|
|
state = REQUESTING;
|
|
timeout = now;
|
|
packet_num = 0;
|
|
} else {
|
|
DEBUG(LOG_ERR, "No server ID in message");
|
|
}
|
|
}
|
|
break;
|
|
case RENEW_REQUESTED:
|
|
case REQUESTING:
|
|
case RENEWING:
|
|
case REBINDING:
|
|
if (*message == DHCPACK) {
|
|
if (!(temp = get_option(&packet, DHCP_LEASE_TIME))) {
|
|
LOG(LOG_ERR,
|
|
"No lease time with ACK, using 1 hour lease");
|
|
lease = 60 * 60;
|
|
} else {
|
|
memcpy(&lease, temp, 4);
|
|
lease = ntohl(lease);
|
|
}
|
|
|
|
/* enter bound state */
|
|
t1 = lease / 2;
|
|
|
|
/* little fixed point for n * .875 */
|
|
t2 = (lease * 0x7) >> 3;
|
|
temp_addr.s_addr = packet.yiaddr;
|
|
LOG(LOG_INFO, "Lease of %s obtained, lease time %ld",
|
|
inet_ntoa(temp_addr), lease);
|
|
start = now;
|
|
timeout = t1 + start;
|
|
requested_ip = packet.yiaddr;
|
|
run_script(&packet,
|
|
((state == RENEWING
|
|
|| state == REBINDING) ? "renew" : "bound"));
|
|
|
|
state = BOUND;
|
|
change_mode(LISTEN_NONE);
|
|
{
|
|
int pid_fd2;
|
|
|
|
if (client_config.quit_after_lease) {
|
|
exit_client(0);
|
|
} else if (!client_config.foreground) {
|
|
pid_fd2 = pidfile_acquire(client_config.pidfile); /* hold lock during fork. */
|
|
if (daemon(0, 0) == -1) {
|
|
perror("fork");
|
|
exit_client(1);
|
|
}
|
|
client_config.foreground = 1; /* Do not fork again. */
|
|
pidfile_write_release(pid_fd2);
|
|
}
|
|
}
|
|
} else if (*message == DHCPNAK) {
|
|
/* return to init state */
|
|
LOG(LOG_INFO, "Received DHCP NAK");
|
|
run_script(&packet, "nak");
|
|
if (state != REQUESTING) {
|
|
run_script(NULL, "deconfig");
|
|
}
|
|
state = INIT_SELECTING;
|
|
timeout = now;
|
|
requested_ip = 0;
|
|
packet_num = 0;
|
|
change_mode(LISTEN_RAW);
|
|
sleep(3); /* avoid excessive network traffic */
|
|
}
|
|
break;
|
|
/* case BOUND, RELEASED: - ignore all packets */
|
|
}
|
|
} else if (retval == -1 && errno == EINTR) {
|
|
/* a signal was caught */
|
|
|
|
} else {
|
|
/* An error occured */
|
|
DEBUG(LOG_ERR, "Error on select");
|
|
}
|
|
|
|
}
|
|
return 0;
|
|
}
|