| /* dhcpd.c |
| * |
| * udhcp DHCP client |
| * |
| * Russ Dill <Russ.Dill@asu.edu> July 2001 |
| * |
| * Converted to busybox by Glenn McGrath August 2002 |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, write to the Free Software |
| * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
| */ |
| |
| #include <stdio.h> |
| #include <sys/time.h> |
| #include <sys/types.h> |
| #include <sys/file.h> |
| #include <unistd.h> |
| #include <getopt.h> |
| #include <stdlib.h> |
| #include <sys/socket.h> |
| #include <netinet/in.h> |
| #include <arpa/inet.h> |
| #include <signal.h> |
| #include <time.h> |
| #include <string.h> |
| #include <sys/ioctl.h> |
| #include <net/if.h> |
| #include <errno.h> |
| #include <netinet/ip.h> |
| #include <netinet/udp.h> |
| #include <sys/types.h> |
| #include <sys/wait.h> |
| |
| #if __GLIBC__ >=2 && __GLIBC_MINOR >= 1 |
| #include <netpacket/packet.h> |
| #include <net/ethernet.h> |
| #else |
| #include <asm/types.h> |
| #include <linux/if_packet.h> |
| #include <linux/if_ether.h> |
| #endif |
| #include "libbb.h" |
| |
| static int state; |
| static unsigned long requested_ip; /* = 0 */ |
| static unsigned long server_addr; |
| static unsigned long timeout; |
| static int packet_num; /* = 0 */ |
| static int fd_main; |
| |
| /* #define DEBUG */ |
| |
| #define VERSION "0.9.7" |
| |
| #define LISTEN_NONE 0 |
| #define LISTEN_KERNEL 1 |
| #define LISTEN_RAW 2 |
| static int listen_mode; |
| |
| #define DEFAULT_SCRIPT "/usr/share/udhcpc/default.script" |
| |
| #define DHCP_END 0xFF |
| #define TYPE_MASK 0x0F |
| #define BROADCAST_FLAG 0x8000 |
| |
| #define SERVER_PORT 67 |
| |
| #define DHCP_MAGIC 0x63825363 |
| |
| #define BOOTREQUEST 1 |
| #define BOOTREPLY 2 |
| |
| #define ETH_10MB 1 |
| #define ETH_10MB_LEN 6 |
| |
| #define OPTION_FIELD 0 |
| #define FILE_FIELD 1 |
| #define SNAME_FIELD 2 |
| |
| #define INIT_SELECTING 0 |
| #define REQUESTING 1 |
| #define BOUND 2 |
| #define RENEWING 3 |
| #define REBINDING 4 |
| #define INIT_REBOOT 5 |
| #define RENEW_REQUESTED 6 |
| #define RELEASED 7 |
| |
| #define CLIENT_PORT 68 |
| |
| #define DHCPDISCOVER 1 |
| #define DHCPOFFER 2 |
| #define DHCPREQUEST 3 |
| #define DHCPDECLINE 4 |
| #define DHCPACK 5 |
| #define DHCPNAK 6 |
| #define DHCPRELEASE 7 |
| #define DHCPINFORM 8 |
| |
| /* DHCP option codes (partial list) */ |
| #define DHCP_PADDING 0x00 |
| #define DHCP_SUBNET 0x01 |
| #define DHCP_TIME_OFFSET 0x02 |
| #define DHCP_ROUTER 0x03 |
| #define DHCP_TIME_SERVER 0x04 |
| #define DHCP_NAME_SERVER 0x05 |
| #define DHCP_DNS_SERVER 0x06 |
| #define DHCP_LOG_SERVER 0x07 |
| #define DHCP_COOKIE_SERVER 0x08 |
| #define DHCP_LPR_SERVER 0x09 |
| #define DHCP_HOST_NAME 0x0c |
| #define DHCP_BOOT_SIZE 0x0d |
| #define DHCP_DOMAIN_NAME 0x0f |
| #define DHCP_SWAP_SERVER 0x10 |
| #define DHCP_ROOT_PATH 0x11 |
| #define DHCP_IP_TTL 0x17 |
| #define DHCP_MTU 0x1a |
| #define DHCP_BROADCAST 0x1c |
| #define DHCP_NTP_SERVER 0x2a |
| #define DHCP_WINS_SERVER 0x2c |
| #define DHCP_REQUESTED_IP 0x32 |
| #define DHCP_LEASE_TIME 0x33 |
| #define DHCP_OPTION_OVER 0x34 |
| #define DHCP_MESSAGE_TYPE 0x35 |
| #define DHCP_SERVER_ID 0x36 |
| #define DHCP_PARAM_REQ 0x37 |
| #define DHCP_MESSAGE 0x38 |
| #define DHCP_MAX_SIZE 0x39 |
| #define DHCP_T1 0x3a |
| #define DHCP_T2 0x3b |
| #define DHCP_VENDOR 0x3c |
| #define DHCP_CLIENT_ID 0x3d |
| |
| /* miscellaneous defines */ |
| #define MAC_BCAST_ADDR (unsigned char *) "\xff\xff\xff\xff\xff\xff" |
| #define OPT_CODE 0 |
| #define OPT_LEN 1 |
| #define OPT_DATA 2 |
| |
| enum { |
| OPTION_IP = 1, |
| OPTION_IP_PAIR, |
| OPTION_STRING, |
| OPTION_BOOLEAN, |
| OPTION_U8, |
| OPTION_U16, |
| OPTION_S16, |
| OPTION_U32, |
| OPTION_S32 |
| }; |
| |
| #define OPTION_REQ 0x10 /* have the client request this option */ |
| #define OPTION_LIST 0x20 /* There can be a list of 1 or more of these */ |
| |
| #ifdef SYSLOG |
| # define LOG(level, str, args...) do { printf(str, ## args); \ |
| printf("\n"); \ |
| syslog(level, str, ## args); } while(0) |
| # define OPEN_LOG(name) openlog(name, 0, 0) |
| # define CLOSE_LOG() closelog() |
| #else |
| # define LOG_EMERG "EMERGENCY!" |
| # define LOG_ALERT "ALERT!" |
| # define LOG_CRIT "critical!" |
| # define LOG_WARNING "warning" |
| # define LOG_ERR "error" |
| # define LOG_INFO "info" |
| # define LOG_DEBUG "debug" |
| # define LOG(level, str, args...) do { printf("%s, " str "\n", level, ## args); } while(0) |
| # define OPEN_LOG(name) |
| # define CLOSE_LOG() |
| #endif |
| |
| #ifdef DEBUG |
| # undef DEBUG |
| # define DEBUG(level, str, args...) LOG(level, str, ## args) |
| # define DEBUGGING |
| #else |
| # define DEBUG(level, str, args...) |
| #endif |
| |
| struct dhcpMessage { |
| u_int8_t op; |
| u_int8_t htype; |
| u_int8_t hlen; |
| u_int8_t hops; |
| u_int32_t xid; |
| u_int16_t secs; |
| u_int16_t flags; |
| u_int32_t ciaddr; |
| u_int32_t yiaddr; |
| u_int32_t siaddr; |
| u_int32_t giaddr; |
| u_int8_t chaddr[16]; |
| u_int8_t sname[64]; |
| u_int8_t file[128]; |
| u_int32_t cookie; |
| u_int8_t options[308]; /* 312 - cookie */ |
| }; |
| |
| struct client_config_t { |
| char foreground; /* Do not fork */ |
| char quit_after_lease; /* Quit after obtaining lease */ |
| char abort_if_no_lease; /* Abort if no lease */ |
| char *interface; /* The name of the interface to use */ |
| char *pidfile; /* Optionally store the process ID */ |
| char *script; /* User script to run at dhcp events */ |
| unsigned char *clientid; /* Optional client id to use */ |
| unsigned char *hostname; /* Optional hostname to use */ |
| int ifindex; /* Index number of the interface to use */ |
| unsigned char arp[6]; /* Our arp address */ |
| }; |
| |
| struct client_config_t client_config = { |
| /* Default options. */ |
| abort_if_no_lease:0, |
| foreground:0, |
| quit_after_lease:0, |
| interface:"eth0", |
| pidfile:NULL, |
| script:DEFAULT_SCRIPT, |
| clientid:NULL, |
| hostname:NULL, |
| ifindex:0, |
| arp:"\0\0\0\0\0\0", /* appease gcc-3.0 */ |
| }; |
| |
| struct dhcp_option { |
| char name[10]; |
| char flags; |
| unsigned char code; |
| }; |
| |
| struct udp_dhcp_packet { |
| struct iphdr ip; |
| struct udphdr udp; |
| struct dhcpMessage data; |
| }; |
| |
| static const struct dhcp_option options[] = { |
| /* name[10] flags code */ |
| {"subnet", OPTION_IP | OPTION_REQ, 0x01}, |
| {"timezone", OPTION_S32, 0x02}, |
| {"router", OPTION_IP | OPTION_LIST | OPTION_REQ, 0x03}, |
| {"timesvr", OPTION_IP | OPTION_LIST, 0x04}, |
| {"namesvr", OPTION_IP | OPTION_LIST, 0x05}, |
| {"dns", OPTION_IP | OPTION_LIST | OPTION_REQ, 0x06}, |
| {"logsvr", OPTION_IP | OPTION_LIST, 0x07}, |
| {"cookiesvr", OPTION_IP | OPTION_LIST, 0x08}, |
| {"lprsvr", OPTION_IP | OPTION_LIST, 0x09}, |
| {"hostname", OPTION_STRING | OPTION_REQ, 0x0c}, |
| {"bootsize", OPTION_U16, 0x0d}, |
| {"domain", OPTION_STRING | OPTION_REQ, 0x0f}, |
| {"swapsvr", OPTION_IP, 0x10}, |
| {"rootpath", OPTION_STRING, 0x11}, |
| {"ipttl", OPTION_U8, 0x17}, |
| {"mtu", OPTION_U16, 0x1a}, |
| {"broadcast", OPTION_IP | OPTION_REQ, 0x1c}, |
| {"ntpsrv", OPTION_IP | OPTION_LIST, 0x2a}, |
| {"wins", OPTION_IP | OPTION_LIST, 0x2c}, |
| {"requestip", OPTION_IP, 0x32}, |
| {"lease", OPTION_U32, 0x33}, |
| {"dhcptype", OPTION_U8, 0x35}, |
| {"serverid", OPTION_IP, 0x36}, |
| {"message", OPTION_STRING, 0x38}, |
| {"tftp", OPTION_STRING, 0x42}, |
| {"bootfile", OPTION_STRING, 0x43}, |
| {"", 0x00, 0x00} |
| }; |
| |
| /* Lengths of the different option types */ |
| static const unsigned char option_lengths[] = { |
| [OPTION_IP] = 4, |
| [OPTION_IP_PAIR] = 8, |
| [OPTION_BOOLEAN] = 1, |
| [OPTION_STRING] = 1, |
| [OPTION_U8] = 1, |
| [OPTION_U16] = 2, |
| [OPTION_S16] = 2, |
| [OPTION_U32] = 4, |
| [OPTION_S32] = 4 |
| }; |
| |
| /* get a rough idea of how long an option will be (rounding up...) */ |
| static const unsigned char max_option_length[] = { |
| [OPTION_IP] = sizeof("255.255.255.255 "), |
| [OPTION_IP_PAIR] = sizeof("255.255.255.255 ") * 2, |
| [OPTION_STRING] = 1, |
| [OPTION_BOOLEAN] = sizeof("yes "), |
| [OPTION_U8] = sizeof("255 "), |
| [OPTION_U16] = sizeof("65535 "), |
| [OPTION_S16] = sizeof("-32768 "), |
| [OPTION_U32] = sizeof("4294967295 "), |
| [OPTION_S32] = sizeof("-2147483684 "), |
| }; |
| |
| /* return the position of the 'end' option (no bounds checking) */ |
| static int end_option(unsigned char *optionptr) |
| { |
| int i = 0; |
| |
| while (optionptr[i] != DHCP_END) { |
| if (optionptr[i] == DHCP_PADDING) |
| i++; |
| else |
| i += optionptr[i + OPT_LEN] + 2; |
| } |
| return i; |
| } |
| |
| /* add an option string to the options (an option string contains an option code, |
| * length, then data) */ |
| static int add_option_string(unsigned char *optionptr, unsigned char *string) |
| { |
| int end = end_option(optionptr); |
| |
| /* end position + string length + option code/length + end option */ |
| if (end + string[OPT_LEN] + 2 + 1 >= 308) { |
| LOG(LOG_ERR, "Option 0x%02x did not fit into the packet!", |
| string[OPT_CODE]); |
| return 0; |
| } |
| DEBUG(LOG_INFO, "adding option 0x%02x", string[OPT_CODE]); |
| memcpy(optionptr + end, string, string[OPT_LEN] + 2); |
| optionptr[end + string[OPT_LEN] + 2] = DHCP_END; |
| return string[OPT_LEN] + 2; |
| } |
| |
| /* add a one to four byte option to a packet */ |
| static int add_simple_option(unsigned char *optionptr, unsigned char code, |
| u_int32_t data) |
| { |
| char length = 0; |
| int i; |
| unsigned char option[2 + 4]; |
| unsigned char *u8; |
| u_int16_t *u16; |
| u_int32_t *u32; |
| u_int32_t aligned; |
| |
| u8 = (unsigned char *) &aligned; |
| u16 = (u_int16_t *) & aligned; |
| u32 = &aligned; |
| |
| for (i = 0; options[i].code; i++) |
| if (options[i].code == code) { |
| length = option_lengths[options[i].flags & TYPE_MASK]; |
| } |
| |
| if (!length) { |
| DEBUG(LOG_ERR, "Could not add option 0x%02x", code); |
| return 0; |
| } |
| |
| option[OPT_CODE] = code; |
| option[OPT_LEN] = length; |
| |
| switch (length) { |
| case 1: |
| *u8 = data; |
| break; |
| case 2: |
| *u16 = data; |
| break; |
| case 4: |
| *u32 = data; |
| break; |
| } |
| |
| memcpy(option + 2, &aligned, length); |
| return add_option_string(optionptr, option); |
| } |
| |
| static u_int16_t checksum(void *addr, int count) |
| { |
| /* Compute Internet Checksum for "count" bytes |
| * beginning at location "addr". |
| */ |
| register int32_t sum = 0; |
| u_int16_t *source = (u_int16_t *) addr; |
| |
| while (count > 1) { |
| /* This is the inner loop */ |
| sum += *source++; |
| count -= 2; |
| } |
| |
| /* Add left-over byte, if any */ |
| if (count > 0) { |
| sum += *(unsigned char *) source; |
| } |
| |
| /* Fold 32-bit sum to 16 bits */ |
| while (sum >> 16) { |
| sum = (sum & 0xffff) + (sum >> 16); |
| } |
| |
| return ~sum; |
| } |
| |
| /* Constuct a ip/udp header for a packet, and specify the source and dest hardware address */ |
| static int raw_packet(struct dhcpMessage *payload, u_int32_t source_ip, |
| int source_port, u_int32_t dest_ip, int dest_port, |
| unsigned char *dest_arp, int ifindex) |
| { |
| int l_fd; |
| int result; |
| struct sockaddr_ll dest; |
| struct udp_dhcp_packet packet; |
| |
| if ((l_fd = socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP))) < 0) { |
| DEBUG(LOG_ERR, "socket call failed: %s", strerror(errno)); |
| return -1; |
| } |
| |
| memset(&dest, 0, sizeof(dest)); |
| memset(&packet, 0, sizeof(packet)); |
| |
| dest.sll_family = AF_PACKET; |
| dest.sll_protocol = htons(ETH_P_IP); |
| dest.sll_ifindex = ifindex; |
| dest.sll_halen = 6; |
| memcpy(dest.sll_addr, dest_arp, 6); |
| if (bind(l_fd, (struct sockaddr *) &dest, sizeof(struct sockaddr_ll)) < 0) { |
| DEBUG(LOG_ERR, "bind call failed: %s", strerror(errno)); |
| close(l_fd); |
| return -1; |
| } |
| |
| packet.ip.protocol = IPPROTO_UDP; |
| packet.ip.saddr = source_ip; |
| packet.ip.daddr = dest_ip; |
| packet.udp.source = htons(source_port); |
| packet.udp.dest = htons(dest_port); |
| packet.udp.len = htons(sizeof(packet.udp) + sizeof(struct dhcpMessage)); /* cheat on the psuedo-header */ |
| packet.ip.tot_len = packet.udp.len; |
| memcpy(&(packet.data), payload, sizeof(struct dhcpMessage)); |
| packet.udp.check = checksum(&packet, sizeof(struct udp_dhcp_packet)); |
| |
| packet.ip.tot_len = htons(sizeof(struct udp_dhcp_packet)); |
| packet.ip.ihl = sizeof(packet.ip) >> 2; |
| packet.ip.version = IPVERSION; |
| packet.ip.ttl = IPDEFTTL; |
| packet.ip.check = checksum(&(packet.ip), sizeof(packet.ip)); |
| |
| result = |
| sendto(l_fd, &packet, sizeof(struct udp_dhcp_packet), 0, |
| (struct sockaddr *) &dest, sizeof(dest)); |
| if (result <= 0) { |
| DEBUG(LOG_ERR, "write on socket failed: %s", strerror(errno)); |
| } |
| close(l_fd); |
| return result; |
| } |
| |
| /* Let the kernel do all the work for packet generation */ |
| static int kernel_packet(struct dhcpMessage *payload, u_int32_t source_ip, |
| int source_port, u_int32_t dest_ip, int dest_port) |
| { |
| int n = 1; |
| int l_fd, result; |
| struct sockaddr_in client; |
| |
| if ((l_fd = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0) { |
| return -1; |
| } |
| |
| if (setsockopt(l_fd, SOL_SOCKET, SO_REUSEADDR, (char *) &n, sizeof(n)) == |
| -1) { |
| return -1; |
| } |
| |
| memset(&client, 0, sizeof(client)); |
| client.sin_family = AF_INET; |
| client.sin_port = htons(source_port); |
| client.sin_addr.s_addr = source_ip; |
| |
| if (bind(l_fd, (struct sockaddr *) &client, sizeof(struct sockaddr)) == |
| -1) { |
| return -1; |
| } |
| |
| memset(&client, 0, sizeof(client)); |
| 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; |
| } |