plugins/check_dhcp.c

   1 /******************************************************************************
   2 *
   3 * CHECK_DHCP.C
   4 *
   5 * Program: DHCP plugin for Nagios
   6 * License: GPL
   7 * Copyright (c) 2001-2004 Ethan Galstad (nagios@nagios.org)
   8 *
   9 * License Information:
  10 *
  11 * This program is free software; you can redistribute it and/or modify
  12 * it under the terms of the GNU General Public License as published by
  13 * the Free Software Foundation; either version 2 of the License, or
  14 * (at your option) any later version.
  15 *
  16 * This program is distributed in the hope that it will be useful,
  17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 * GNU General Public License for more details.
  20 *
  21 * You should have received a copy of the GNU General Public License
  22 * along with this program; if not, write to the Free Software
  23 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  24 *
  25 *****************************************************************************/
  26
  27 #include "common.h"
  28 #include "netutils.h"
  29 #include "utils.h"
  30
  31 #include <stdio.h>
  32 #include <stdlib.h>
  33 #include <string.h>
  34 #include <errno.h>
  35 #include <unistd.h>
  36 #include <sys/time.h>
  37 #include <sys/ioctl.h>
  38 #include <fcntl.h>
  39 #include <getopt.h>
  40 #include <sys/socket.h>
  41 #include <sys/types.h>
  42 #include <netdb.h>
  43 #include <netinet/in.h>
  44 #include <net/if.h>
  45 #include <arpa/inet.h>
  46
  47 #if defined( __linux__ )
  48 #include <linux/if_ether.h>
  49 #include <features.h>
  50 #else
  51 #include <netinet/if_ether.h>
  52 #include <sys/sysctl.h>
  53 #include <net/if_dl.h>
  54 #endif
  55
  56 const char *progname = "check_dhcp";
  57
  58 /*#define DEBUG*/
  59 #define HAVE_GETOPT_H
  60
  61
  62 /**** Common definitions ****/
  63
  64 #define STATE_OK          0
  65 #define STATE_WARNING     1
  66 #define STATE_CRITICAL    2
  67 #define STATE_UNKNOWN     -1
  68
  69 #define OK                0
  70 #define ERROR             -1
  71
  72 #define FALSE             0
  73 #define TRUE              1
  74
  75
  76 /**** DHCP definitions ****/
  77
  78 #define MAX_DHCP_CHADDR_LENGTH           16
  79 #define MAX_DHCP_SNAME_LENGTH            64
  80 #define MAX_DHCP_FILE_LENGTH             128
  81 #define MAX_DHCP_OPTIONS_LENGTH          312
  82
  83
  84 typedef struct dhcp_packet_struct{
  85         u_int8_t  op;                   /* packet type */
  86         u_int8_t  htype;                /* type of hardware address for this machine (Ethernet, etc) */
  87         u_int8_t  hlen;                 /* length of hardware address (of this machine) */
  88         u_int8_t  hops;                 /* hops */
  89         u_int32_t xid;                  /* random transaction id number - chosen by this machine */
  90         u_int16_t secs;                 /* seconds used in timing */
  91         u_int16_t flags;                /* flags */
  92         struct in_addr ciaddr;          /* IP address of this machine (if we already have one) */
  93         struct in_addr yiaddr;          /* IP address of this machine (offered by the DHCP server) */
  94         struct in_addr siaddr;          /* IP address of DHCP server */
  95         struct in_addr giaddr;          /* IP address of DHCP relay */
  96         unsigned char chaddr [MAX_DHCP_CHADDR_LENGTH];      /* hardware address of this machine */
  97         char sname [MAX_DHCP_SNAME_LENGTH];    /* name of DHCP server */
  98         char file [MAX_DHCP_FILE_LENGTH];      /* boot file name (used for diskless booting?) */
  99         char options[MAX_DHCP_OPTIONS_LENGTH];  /* options */
 100         }dhcp_packet;
 101
 102
 103 typedef struct dhcp_offer_struct{
 104         struct in_addr server_address;   /* address of DHCP server that sent this offer */
 105         struct in_addr offered_address;  /* the IP address that was offered to us */
 106         u_int32_t lease_time;            /* lease time in seconds */
 107         u_int32_t renewal_time;          /* renewal time in seconds */
 108         u_int32_t rebinding_time;        /* rebinding time in seconds */
 109         struct dhcp_offer_struct *next;
 110         }dhcp_offer;
 111
 112
 113 typedef struct requested_server_struct{
 114         struct in_addr server_address;
 115         struct requested_server_struct *next;
 116         }requested_server;
 117
 118
 119 #define BOOTREQUEST     1
 120 #define BOOTREPLY       2
 121
 122 #define DHCPDISCOVER    1
 123 #define DHCPOFFER       2
 124 #define DHCPREQUEST     3
 125 #define DHCPDECLINE     4
 126 #define DHCPACK         5
 127 #define DHCPNACK        6
 128 #define DHCPRELEASE     7
 129
 130 #define DHCP_OPTION_MESSAGE_TYPE        53
 131 #define DHCP_OPTION_HOST_NAME           12
 132 #define DHCP_OPTION_BROADCAST_ADDRESS   28
 133 #define DHCP_OPTION_REQUESTED_ADDRESS   50
 134 #define DHCP_OPTION_LEASE_TIME          51
 135 #define DHCP_OPTION_RENEWAL_TIME        58
 136 #define DHCP_OPTION_REBINDING_TIME      59
 137
 138 #define DHCP_INFINITE_TIME              0xFFFFFFFF
 139
 140 #define DHCP_BROADCAST_FLAG 32768
 141
 142 #define DHCP_SERVER_PORT   67
 143 #define DHCP_CLIENT_PORT   68
 144
 145 #define ETHERNET_HARDWARE_ADDRESS            1     /* used in htype field of dhcp packet */
 146 #define ETHERNET_HARDWARE_ADDRESS_LENGTH     6     /* length of Ethernet hardware addresses */
 147
 148 unsigned char client_hardware_address[MAX_DHCP_CHADDR_LENGTH]="";
 149
 150 char network_interface_name[8]="eth0";
 151
 152 u_int32_t packet_xid=0;
 153
 154 u_int32_t dhcp_lease_time=0;
 155 u_int32_t dhcp_renewal_time=0;
 156 u_int32_t dhcp_rebinding_time=0;
 157
 158 int dhcpoffer_timeout=2;
 159
 160 dhcp_offer *dhcp_offer_list=NULL;
 161 requested_server *requested_server_list=NULL;
 162
 163 int valid_responses=0;     /* number of valid DHCPOFFERs we received */
 164 int requested_servers=0;
 165 int requested_responses=0;
 166
 167 int request_specific_address=FALSE;
 168 int received_requested_address=FALSE;
 169 struct in_addr requested_address;
 170
 171
 172 int process_arguments(int, char **);
 173 int call_getopt(int, char **);
 174 int validate_arguments(void);
 175 void print_usage(void);
 176 void print_help(void);
 177
 178 int get_hardware_address(int,char *);
 179
 180 int send_dhcp_discover(int);
 181 int get_dhcp_offer(int);
 182
 183 int get_results(void);
 184
 185 int add_dhcp_offer(struct in_addr,dhcp_packet *);
 186 int free_dhcp_offer_list(void);
 187 int free_requested_server_list(void);
 188
 189 int create_dhcp_socket(void);
 190 int close_dhcp_socket(int);
 191 int send_dhcp_packet(void *,int,int,struct sockaddr_in *);
 192 int receive_dhcp_packet(void *,int,int,int,struct sockaddr_in *);
 193
 194
 195
 196 int main(int argc, char **argv){
 197         int dhcp_socket;
 198         int result;
 199
 200         if(process_arguments(argc,argv)!=OK){
 201                 /*usage("Invalid command arguments supplied\n");*/
 202                 printf("Invalid command arguments supplied\n");
 203                 exit(STATE_UNKNOWN);
 204                 }
 205
 206
 207         /* create socket for DHCP communications */
 208         dhcp_socket=create_dhcp_socket();
 209
 210         /* get hardware address of client machine */
 211         get_hardware_address(dhcp_socket,network_interface_name);
 212
 213         /* send DHCPDISCOVER packet */
 214         send_dhcp_discover(dhcp_socket);
 215
 216         /* wait for a DHCPOFFER packet */
 217         get_dhcp_offer(dhcp_socket);
 218
 219         /* close socket we created */
 220         close_dhcp_socket(dhcp_socket);
 221
 222         /* determine state/plugin output to return */
 223         result=get_results();
 224
 225         /* free allocated memory */
 226         free_dhcp_offer_list();
 227         free_requested_server_list();
 228
 229         return result;
 230         }
 231
 232
 233
 234 /* determines hardware address on client machine */
 235 int get_hardware_address(int sock,char *interface_name){
 236 #if defined(__linux__)
 237         struct ifreq ifr;
 238
 239         strncpy((char *)&ifr.ifr_name,interface_name,sizeof(ifr.ifr_name));
 240
 241         /* try and grab hardware address of requested interface */
 242         if(ioctl(sock,SIOCGIFHWADDR,&ifr)<0){
 243                 printf("Error: Could not get hardware address of interface '%s'\n",interface_name);
 244                 exit(STATE_UNKNOWN);
 245                 }
 246
 247         memcpy(&client_hardware_address[0],&ifr.ifr_hwaddr.sa_data,6);
 248 #else
 249         /* Code from getmac.c posted at http://lists.freebsd.org/pipermail/freebsd-hackers/2004-June/007415.html
 250          * by Alecs King based on Unix Network programming Ch 17
 251          */
 252
 253         int                     mib[6], len;
 254         char                    *buf;
 255         unsigned char           *ptr;
 256         struct if_msghdr        *ifm;
 257         struct sockaddr_dl      *sdl;
 258
 259         mib[0] = CTL_NET;
 260         mib[1] = AF_ROUTE;
 261         mib[2] = 0;
 262         mib[3] = AF_LINK;
 263         mib[4] = NET_RT_IFLIST;
 264
 265         if ((mib[5] = if_nametoindex(interface_name)) == 0) {
 266                 perror("if_nametoindex error");
 267                 exit(2);
 268         }
 269
 270         if (sysctl(mib, 6, NULL, &len, NULL, 0) < 0) {
 271                 perror("sysctl 1 error");
 272                 exit(3);
 273         }
 274
 275         if ((buf = malloc(len)) == NULL) {
 276                 perror("malloc error");
 277                 exit(4);
 278         }
 279
 280         if (sysctl(mib, 6, buf, &len, NULL, 0) < 0) {
 281                 perror("sysctl 2 error");
 282                 exit(5);
 283         }
 284
 285         ifm = (struct if_msghdr *)buf;
 286         sdl = (struct sockaddr_dl *)(ifm + 1);
 287         ptr = (unsigned char *)LLADDR(sdl);
 288         memcpy(&client_hardware_address[0], ptr, 6) ;
 289 #endif
 290
 291
 292 #ifdef DEBUG
 293         printf("Hardware address: %02x:%02x:%02x:",client_hardware_address[0],client_hardware_address[1],client_hardware_address[2]);
 294         printf("%02x:",client_hardware_address[3]);
 295         printf("%02x:%02x\n",client_hardware_address[4],client_hardware_address[5]);
 296         printf("\n");
 297 #endif
 298
 299         return OK;
 300         }
 301
 302
 303 /* sends a DHCPDISCOVER broadcast message in an attempt to find DHCP servers */
 304 int send_dhcp_discover(int sock){
 305         dhcp_packet discover_packet;
 306         struct sockaddr_in sockaddr_broadcast;
 307
 308
 309         /* clear the packet data structure */
 310         bzero(&discover_packet,sizeof(discover_packet));
 311
 312
 313         /* boot request flag (backward compatible with BOOTP servers) */
 314         discover_packet.op=BOOTREQUEST;
 315
 316         /* hardware address type */
 317         discover_packet.htype=ETHERNET_HARDWARE_ADDRESS;
 318
 319         /* length of our hardware address */
 320         discover_packet.hlen=ETHERNET_HARDWARE_ADDRESS_LENGTH;
 321
 322         discover_packet.hops=0;
 323
 324         /* transaction id is supposed to be random */
 325         srand(time(NULL));
 326         packet_xid=random();
 327         discover_packet.xid=htonl(packet_xid);
 328
 329         /**** WHAT THE HECK IS UP WITH THIS?!?  IF I DON'T MAKE THIS CALL, ONLY ONE SERVER RESPONSE IS PROCESSED!!!! ****/
 330         /* downright bizzarre... */
 331         ntohl(discover_packet.xid);
 332
 333         /*discover_packet.secs=htons(65535);*/
 334         discover_packet.secs=0xFF;
 335
 336         /* tell server it should broadcast its response */
 337         discover_packet.flags=htons(DHCP_BROADCAST_FLAG);
 338
 339         /* our hardware address */
 340         memcpy(discover_packet.chaddr,client_hardware_address,ETHERNET_HARDWARE_ADDRESS_LENGTH);
 341
 342         /* first four bytes of options field is magic cookie (as per RFC 2132) */
 343         discover_packet.options[0]='\x63';
 344         discover_packet.options[1]='\x82';
 345         discover_packet.options[2]='\x53';
 346         discover_packet.options[3]='\x63';
 347
 348         /* DHCP message type is embedded in options field */
 349         discover_packet.options[4]=DHCP_OPTION_MESSAGE_TYPE;    /* DHCP message type option identifier */
 350         discover_packet.options[5]='\x01';               /* DHCP message option length in bytes */
 351         discover_packet.options[6]=DHCPDISCOVER;
 352
 353         /* the IP address we're requesting */
 354         if(request_specific_address==TRUE){
 355                 discover_packet.options[7]=DHCP_OPTION_REQUESTED_ADDRESS;
 356                 discover_packet.options[8]='\x04';
 357                 memcpy(&discover_packet.options[9],&requested_address,sizeof(requested_address));
 358                 }
 359
 360         /* send the DHCPDISCOVER packet to broadcast address */
 361         sockaddr_broadcast.sin_family=AF_INET;
 362         sockaddr_broadcast.sin_port=htons(DHCP_SERVER_PORT);
 363         sockaddr_broadcast.sin_addr.s_addr=INADDR_BROADCAST;
 364         bzero(&sockaddr_broadcast.sin_zero,sizeof(sockaddr_broadcast.sin_zero));
 365
 366
 367 #ifdef DEBUG
 368         printf("DHCPDISCOVER to %s port %d\n",inet_ntoa(sockaddr_broadcast.sin_addr),ntohs(sockaddr_broadcast.sin_port));
 369         printf("DHCPDISCOVER XID: %lu (0x%X)\n",ntohl(discover_packet.xid),ntohl(discover_packet.xid));
 370         printf("DHCDISCOVER ciaddr:  %s\n",inet_ntoa(discover_packet.ciaddr));
 371         printf("DHCDISCOVER yiaddr:  %s\n",inet_ntoa(discover_packet.yiaddr));
 372         printf("DHCDISCOVER siaddr:  %s\n",inet_ntoa(discover_packet.siaddr));
 373         printf("DHCDISCOVER giaddr:  %s\n",inet_ntoa(discover_packet.giaddr));
 374 #endif
 375
 376         /* send the DHCPDISCOVER packet out */
 377         send_dhcp_packet(&discover_packet,sizeof(discover_packet),sock,&sockaddr_broadcast);
 378
 379 #ifdef DEBUG
 380         printf("\n\n");
 381 #endif
 382
 383         return OK;
 384         }
 385
 386
 387
 388
 389 /* waits for a DHCPOFFER message from one or more DHCP servers */
 390 int get_dhcp_offer(int sock){
 391         dhcp_packet offer_packet;
 392         struct sockaddr_in source;
 393         int result=OK;
 394         int timeout=1;
 395         int responses=0;
 396         int x;
 397         time_t start_time;
 398         time_t current_time;
 399
 400         time(&start_time);
 401
 402         /* receive as many responses as we can */
 403         for(responses=0,valid_responses=0;;){
 404
 405                 time(&current_time);
 406                 if((current_time-start_time)>=dhcpoffer_timeout)
 407                         break;
 408
 409 #ifdef DEBUG
 410                 printf("\n\n");
 411 #endif
 412
 413                 bzero(&source,sizeof(source));
 414                 bzero(&offer_packet,sizeof(offer_packet));
 415
 416                 result=OK;
 417                 result=receive_dhcp_packet(&offer_packet,sizeof(offer_packet),sock,dhcpoffer_timeout,&source);
 418
 419                 if(result!=OK){
 420 #ifdef DEBUG
 421                         printf("Result=ERROR\n");
 422 #endif
 423                         continue;
 424                         }
 425                 else{
 426 #ifdef DEBUG
 427                         printf("Result=OK\n");
 428 #endif
 429                         responses++;
 430                         }
 431
 432 #ifdef DEBUG
 433                 printf("DHCPOFFER from IP address %s\n",inet_ntoa(source.sin_addr));
 434                 printf("DHCPOFFER XID: %lu (0x%X)\n",ntohl(offer_packet.xid),ntohl(offer_packet.xid));
 435 #endif
 436
 437                 /* check packet xid to see if its the same as the one we used in the discover packet */
 438                 if(ntohl(offer_packet.xid)!=packet_xid){
 439 #ifdef DEBUG
 440                         printf("DHCPOFFER XID (%lu) did not match DHCPDISCOVER XID (%lu) - ignoring packet\n",ntohl(offer_packet.xid),packet_xid);
 441 #endif
 442                         continue;
 443                         }
 444
 445                 /* check hardware address */
 446                 result=OK;
 447 #ifdef DEBUG
 448                 printf("DHCPOFFER chaddr: ");
 449 #endif
 450                 for(x=0;x<ETHERNET_HARDWARE_ADDRESS_LENGTH;x++){
 451 #ifdef DEBUG
 452                         printf("%02X",(unsigned char)offer_packet.chaddr[x]);
 453 #endif
 454                         if(offer_packet.chaddr[x]!=client_hardware_address[x]){
 455                                 result=ERROR;
 456                                 }
 457                         }
 458 #ifdef DEBUG
 459                 printf("\n");
 460 #endif
 461                 if(result==ERROR){
 462 #ifdef DEBUG
 463                         printf("DHCPOFFER hardware address did not match our own - ignoring packet\n");
 464 #endif
 465                         continue;
 466                         }
 467
 468 #ifdef DEBUG
 469                 printf("DHCPOFFER ciaddr: %s\n",inet_ntoa(offer_packet.ciaddr));
 470                 printf("DHCPOFFER yiaddr: %s\n",inet_ntoa(offer_packet.yiaddr));
 471                 printf("DHCPOFFER siaddr: %s\n",inet_ntoa(offer_packet.siaddr));
 472                 printf("DHCPOFFER giaddr: %s\n",inet_ntoa(offer_packet.giaddr));
 473 #endif
 474
 475                 add_dhcp_offer(source.sin_addr,&offer_packet);
 476
 477                 valid_responses++;
 478                 }
 479
 480 #ifdef DEBUG
 481         printf("Total responses seen on the wire: %d\n",responses);
 482         printf("Valid responses for this machine: %d\n",valid_responses);
 483 #endif
 484
 485         return OK;
 486         }
 487
 488
 489
 490 /* sends a DHCP packet */
 491 int send_dhcp_packet(void *buffer, int buffer_size, int sock, struct sockaddr_in *dest){
 492         struct sockaddr_in myname;
 493         int result;
 494
 495         result=sendto(sock,(char *)buffer,buffer_size,0,(struct sockaddr *)dest,sizeof(*dest));
 496
 497 #ifdef DEBUG
 498         printf("send_dhcp_packet result: %d\n",result);
 499 #endif
 500
 501         if(result<0)
 502                 return ERROR;
 503
 504         return OK;
 505         }
 506
 507
 508
 509 /* receives a DHCP packet */
 510 int receive_dhcp_packet(void *buffer, int buffer_size, int sock, int timeout, struct sockaddr_in *address){
 511         struct timeval tv;
 512         fd_set readfds;
 513         int recv_result;
 514         socklen_t address_size;
 515         struct sockaddr_in source_address;
 516
 517
 518         /* wait for data to arrive (up time timeout) */
 519         tv.tv_sec=timeout;
 520         tv.tv_usec=0;
 521         FD_ZERO(&readfds);
 522         FD_SET(sock,&readfds);
 523         select(sock+1,&readfds,NULL,NULL,&tv);
 524
 525         /* make sure some data has arrived */
 526         if(!FD_ISSET(sock,&readfds)){
 527 #ifdef DEBUG
 528                 printf("No (more) data received\n");
 529 #endif
 530                 return ERROR;
 531                 }
 532
 533         else{
 534
 535                 /* why do we need to peek first?  i don't know, its a hack.  without it, the source address of the first packet received was
 536                    not being interpreted correctly.  sigh... */
 537                 bzero(&source_address,sizeof(source_address));
 538                 address_size=sizeof(source_address);
 539                 recv_result=recvfrom(sock,(char *)buffer,buffer_size,MSG_PEEK,(struct sockaddr *)&source_address,&address_size);
 540 #ifdef DEBUG
 541                 printf("recv_result_1: %d\n",recv_result);
 542 #endif
 543                 recv_result=recvfrom(sock,(char *)buffer,buffer_size,0,(struct sockaddr *)&source_address,&address_size);
 544 #ifdef DEBUG
 545                 printf("recv_result_2: %d\n",recv_result);
 546 #endif
 547
 548                 if(recv_result==-1){
 549 #ifdef DEBUG
 550                         printf("recvfrom() failed, ");
 551                         printf("errno: (%d) -> %s\n",errno,strerror(errno));
 552 #endif
 553                         return ERROR;
 554                         }
 555                 else{
 556 #ifdef DEBUG
 557                         printf("receive_dhcp_packet() result: %d\n",recv_result);
 558                         printf("receive_dhcp_packet() source: %s\n",inet_ntoa(source_address.sin_addr));
 559 #endif
 560
 561                         memcpy(address,&source_address,sizeof(source_address));
 562                         return OK;
 563                         }
 564                 }
 565
 566         return OK;
 567         }
 568
 569
 570
 571 /* creates a socket for DHCP communication */
 572 int create_dhcp_socket(void){
 573         struct sockaddr_in myname;
 574         struct ifreq interface;
 575         int sock;
 576         int flag=1;
 577
 578         /* Set up the address we're going to bind to. */
 579         bzero(&myname,sizeof(myname));
 580         myname.sin_family=AF_INET;
 581         myname.sin_port=htons(DHCP_CLIENT_PORT);
 582         myname.sin_addr.s_addr=INADDR_ANY;                 /* listen on any address */
 583         bzero(&myname.sin_zero,sizeof(myname.sin_zero));
 584
 585         /* create a socket for DHCP communications */
 586         sock=socket(AF_INET,SOCK_DGRAM,IPPROTO_UDP);
 587         if(sock<0){
 588                 printf("Error: Could not create socket!\n");
 589                 exit(STATE_UNKNOWN);
 590                 }
 591
 592 #ifdef DEBUG
 593         printf("DHCP socket: %d\n",sock);
 594 #endif
 595
 596         /* set the reuse address flag so we don't get errors when restarting */
 597         flag=1;
 598         if(setsockopt(sock,SOL_SOCKET,SO_REUSEADDR,(char *)&flag,sizeof(flag))<0){
 599                 printf("Error: Could not set reuse address option on DHCP socket!\n");
 600                 exit(STATE_UNKNOWN);
 601                 }
 602
 603         /* set the broadcast option - we need this to listen to DHCP broadcast messages */
 604         if(setsockopt(sock,SOL_SOCKET,SO_BROADCAST,(char *)&flag,sizeof flag)<0){
 605                 printf("Error: Could not set broadcast option on DHCP socket!\n");
 606                 exit(STATE_UNKNOWN);
 607                 }
 608
 609         /* bind socket to interface */
 610 #if defined(__linux__)
 611         strncpy(interface.ifr_ifrn.ifrn_name,network_interface_name,IFNAMSIZ);
 612         if(setsockopt(sock,SOL_SOCKET,SO_BINDTODEVICE,(char *)&interface,sizeof(interface))<0){
 613                 printf("Error: Could not bind socket to interface %s.  Check your privileges...\n",network_interface_name);
 614                 exit(STATE_UNKNOWN);
 615                 }
 616
 617 #else
 618         strncpy(interface.ifr_name,network_interface_name,IFNAMSIZ);
 619 #endif
 620
 621         /* bind the socket */
 622         if(bind(sock,(struct sockaddr *)&myname,sizeof(myname))<0){
 623                 printf("Error: Could not bind to DHCP socket (port %d)!  Check your privileges...\n",DHCP_CLIENT_PORT);
 624                 exit(STATE_UNKNOWN);
 625                 }
 626
 627         return sock;
 628         }
 629
 630
 631
 632
 633
 634 /* closes DHCP socket */
 635 int close_dhcp_socket(int sock){
 636
 637         close(sock);
 638
 639         return OK;
 640         }
 641
 642
 643
 644
 645 /* adds a requested server address to list in memory */
 646 int add_requested_server(struct in_addr server_address){
 647         requested_server *new_server;
 648
 649         new_server=(requested_server *)malloc(sizeof(requested_server));
 650         if(new_server==NULL)
 651                 return ERROR;
 652
 653         new_server->server_address=server_address;
 654
 655         new_server->next=requested_server_list;
 656         requested_server_list=new_server;
 657
 658         requested_servers++;
 659
 660 #ifdef DEBUG
 661         printf("Requested server address: %s\n",inet_ntoa(new_server->server_address));
 662 #endif
 663
 664         return OK;
 665         }
 666
 667
 668
 669
 670 /* adds a DHCP OFFER to list in memory */
 671 int add_dhcp_offer(struct in_addr source,dhcp_packet *offer_packet){
 672         dhcp_offer *new_offer;
 673         int x;
 674         int y;
 675         unsigned option_type;
 676         unsigned option_length;
 677
 678         if(offer_packet==NULL)
 679                 return ERROR;
 680
 681         /* process all DHCP options present in the packet */
 682         for(x=4;x<MAX_DHCP_OPTIONS_LENGTH;){
 683
 684                 /* end of options (0 is really just a pad, but bail out anyway) */
 685                 if((int)offer_packet->options[x]==-1 || (int)offer_packet->options[x]==0)
 686                         break;
 687
 688                 /* get option type */
 689                 option_type=offer_packet->options[x++];
 690
 691                 /* get option length */
 692                 option_length=offer_packet->options[x++];
 693
 694 #ifdef DEBUG
 695                 printf("Option: %d (0x%02X)\n",option_type,option_length);
 696 #endif
 697
 698                 /* get option data */
 699                 if(option_type==DHCP_OPTION_LEASE_TIME)
 700                         dhcp_lease_time=ntohl(*((u_int32_t *)&offer_packet->options[x]));
 701                 if(option_type==DHCP_OPTION_RENEWAL_TIME)
 702                         dhcp_renewal_time=ntohl(*((u_int32_t *)&offer_packet->options[x]));
 703                 if(option_type==DHCP_OPTION_REBINDING_TIME)
 704                         dhcp_rebinding_time=ntohl(*((u_int32_t *)&offer_packet->options[x]));
 705
 706                 /* skip option data we're ignoring */
 707                 else
 708                         for(y=0;y<option_length;y++,x++);
 709                 }
 710
 711 #ifdef DEBUG
 712         if(dhcp_lease_time==DHCP_INFINITE_TIME)
 713                 printf("Lease Time: Infinite\n");
 714         else
 715                 printf("Lease Time: %lu seconds\n",(unsigned long)dhcp_lease_time);
 716         if(dhcp_renewal_time==DHCP_INFINITE_TIME)
 717                 printf("Renewal Time: Infinite\n");
 718         else
 719                 printf("Renewal Time: %lu seconds\n",(unsigned long)dhcp_renewal_time);
 720         if(dhcp_rebinding_time==DHCP_INFINITE_TIME)
 721                 printf("Rebinding Time: Infinite\n");
 722         printf("Rebinding Time: %lu seconds\n",(unsigned long)dhcp_rebinding_time);
 723 #endif
 724
 725         new_offer=(dhcp_offer *)malloc(sizeof(dhcp_offer));
 726
 727         if(new_offer==NULL)
 728                 return ERROR;
 729
 730
 731         new_offer->server_address=source;
 732         new_offer->offered_address=offer_packet->yiaddr;
 733         new_offer->lease_time=dhcp_lease_time;
 734         new_offer->renewal_time=dhcp_renewal_time;
 735         new_offer->rebinding_time=dhcp_rebinding_time;
 736
 737
 738 #ifdef DEBUG
 739         printf("Added offer from server @ %s",inet_ntoa(new_offer->server_address));
 740         printf(" of IP address %s\n",inet_ntoa(new_offer->offered_address));
 741 #endif
 742
 743         /* add new offer to head of list */
 744         new_offer->next=dhcp_offer_list;
 745         dhcp_offer_list=new_offer;
 746
 747         return OK;
 748         }
 749
 750
 751
 752
 753 /* frees memory allocated to DHCP OFFER list */
 754 int free_dhcp_offer_list(void){
 755         dhcp_offer *this_offer;
 756         dhcp_offer *next_offer;
 757
 758         for(this_offer=dhcp_offer_list;this_offer!=NULL;this_offer=next_offer){
 759                 next_offer=this_offer->next;
 760                 free(this_offer);
 761                 }
 762
 763         return OK;
 764         }
 765
 766
 767
 768
 769 /* frees memory allocated to requested server list */
 770 int free_requested_server_list(void){
 771         requested_server *this_server;
 772         requested_server *next_server;
 773
 774         for(this_server=requested_server_list;this_server!=NULL;this_server=next_server){
 775                 next_server=this_server->next;
 776                 free(this_server);
 777                 }
 778
 779         return OK;
 780         }
 781
 782
 783 /* gets state and plugin output to return */
 784 int get_results(void){
 785         dhcp_offer *temp_offer;
 786         requested_server *temp_server;
 787         int result;
 788         u_int32_t max_lease_time=0;
 789
 790         received_requested_address=FALSE;
 791
 792         /* checks responses from requested servers */
 793         requested_responses=0;
 794         if(requested_servers>0){
 795
 796                 for(temp_server=requested_server_list;temp_server!=NULL;temp_server=temp_server->next){
 797
 798                         for(temp_offer=dhcp_offer_list;temp_offer!=NULL;temp_offer=temp_offer->next){
 799
 800                                 /* get max lease time we were offered */
 801                                 if(temp_offer->lease_time>max_lease_time || temp_offer->lease_time==DHCP_INFINITE_TIME)
 802                                         max_lease_time=temp_offer->lease_time;
 803
 804                                 /* see if we got the address we requested */
 805                                 if(!memcmp(&requested_address,&temp_offer->offered_address,sizeof(requested_address)))
 806                                         received_requested_address=TRUE;
 807
 808                                 /* see if the servers we wanted a response from talked to us or not */
 809                                 if(!memcmp(&temp_offer->server_address,&temp_server->server_address,sizeof(temp_server->server_address))){
 810 #ifdef DEBUG
 811                                         printf("DHCP Server Match: Offerer=%s",inet_ntoa(temp_offer->server_address));
 812                                         printf(" Requested=%s\n",inet_ntoa(temp_server->server_address));
 813 #endif
 814                                         requested_responses++;
 815                                         }
 816                                 }
 817                         }
 818
 819                 }
 820
 821         /* else check and see if we got our requested address from any server */
 822         else{
 823
 824                 for(temp_offer=dhcp_offer_list;temp_offer!=NULL;temp_offer=temp_offer->next){
 825
 826                         /* get max lease time we were offered */
 827                         if(temp_offer->lease_time>max_lease_time || temp_offer->lease_time==DHCP_INFINITE_TIME)
 828                                 max_lease_time=temp_offer->lease_time;
 829
 830                         /* see if we got the address we requested */
 831                         if(!memcmp(&requested_address,&temp_offer->offered_address,sizeof(requested_address)))
 832                                 received_requested_address=TRUE;
 833                         }
 834                 }
 835
 836         result=STATE_OK;
 837         if(valid_responses==0)
 838                 result=STATE_CRITICAL;
 839         else if(requested_servers>0 && requested_responses==0)
 840                 result=STATE_CRITICAL;
 841         else if(requested_responses<requested_servers)
 842                 result=STATE_WARNING;
 843         else if(request_specific_address==TRUE && received_requested_address==FALSE)
 844                 result=STATE_WARNING;
 845
 846
 847         printf("DHCP %s: ",(result==STATE_OK)?"ok":"problem");
 848
 849         /* we didn't receive any DHCPOFFERs */
 850         if(dhcp_offer_list==NULL){
 851                 printf("No DHCPOFFERs were received.\n");
 852                 return result;
 853                 }
 854
 855         printf("Received %d DHCPOFFER(s)",valid_responses);
 856
 857         if(requested_servers>0)
 858                 printf(", %s%d of %d requested servers responded",((requested_responses<requested_servers) && requested_responses>0)?"only ":"",requested_responses,requested_servers);
 859
 860         if(request_specific_address==TRUE)
 861                 printf(", requested address (%s) was %soffered",inet_ntoa(requested_address),(received_requested_address==TRUE)?"":"not ");
 862
 863         printf(", max lease time = ");
 864         if(max_lease_time==DHCP_INFINITE_TIME)
 865                 printf("Infinity");
 866         else
 867                 printf("%lu sec",(unsigned long)max_lease_time);
 868
 869         printf(".\n");
 870
 871         return result;
 872         }
 873
 874
 875
 876
 877
 878
 879 /* print usage help */
 880 void print_help(void){
 881
 882         /*print_revision(progname,"$Revision$");*/
 883
 884         printf("Copyright (c) 2001-2004 Ethan Galstad (nagios@nagios.org)\n\n");
 885         printf("This plugin tests the availability of DHCP servers on a network.\n\n");
 886
 887         print_usage();
 888
 889         printf
 890                 ("\nOptions:\n"
 891                  " -s, --serverip=IPADDRESS\n"
 892                  "   IP address of DHCP server that we must hear from\n"
 893                  " -r, --requestedip=IPADDRESS\n"
 894                  "   IP address that should be offered by at least one DHCP server\n"
 895                  " -t, --timeout=INTEGER\n"
 896                  "   Seconds to wait for DHCPOFFER before timeout occurs\n"
 897                  " -i, --interface=STRING\n"
 898                  "   Interface to to use for listening (i.e. eth0)\n"
 899                  " -v, --verbose\n"
 900                  "   Print extra information (command-line use only)\n"
 901                  " -h, --help\n"
 902                  "   Print detailed help screen\n"
 903                  " -V, --version\n"
 904                  "   Print version information\n\n"
 905                  );
 906
 907         /*support();*/
 908
 909         return;
 910         }
 911
 912
 913 /* prints usage information */
 914 void print_usage(void){
 915
 916         printf("Usage: %s [-s serverip] [-r requestedip] [-t timeout] [-i interface]\n",progname);
 917         printf("       %s --help\n",progname);
 918         printf("       %s --version\n",progname);
 919
 920         return;
 921         }
 922
 923
 924
 925
 926 /* process command-line arguments */
 927 int process_arguments(int argc, char **argv){
 928         int c;
 929
 930         if(argc<1)
 931                 return ERROR;
 932
 933         c=0;
 934         while((c+=(call_getopt(argc-c,&argv[c])))<argc){
 935
 936                 /*
 937                 if(is_option(argv[c]))
 938                         continue;
 939                 */
 940                 }
 941
 942         return validate_arguments();
 943         }
 944
 945
 946
 947 int call_getopt(int argc, char **argv){
 948         int c=0;
 949         int i=0;
 950         struct in_addr ipaddress;
 951
 952 #ifdef HAVE_GETOPT_H
 953         int option_index = 0;
 954         static struct option long_options[] =
 955         {
 956                 {"serverip",       required_argument,0,'s'},
 957                 {"requestedip",    required_argument,0,'r'},
 958                 {"timeout",        required_argument,0,'t'},
 959                 {"interface",      required_argument,0,'i'},
 960                 {"verbose",        no_argument,      0,'v'},
 961                 {"version",        no_argument,      0,'V'},
 962                 {"help",           no_argument,      0,'h'},
 963                 {0,0,0,0}
 964         };
 965 #endif
 966
 967         while(1){
 968 #ifdef HAVE_GETOPT_H
 969                 c=getopt_long(argc,argv,"+hVvt:s:r:t:i:",long_options,&option_index);
 970 #else
 971                 c=getopt(argc,argv,"+?hVvt:s:r:t:i:");
 972 #endif
 973
 974                 i++;
 975
 976                 if(c==-1||c==EOF||c==1)
 977                         break;
 978
 979                 switch(c){
 980                 case 'w':
 981                 case 'r':
 982                 case 't':
 983                 case 'i':
 984                         i++;
 985                         break;
 986                 default:
 987                         break;
 988                         }
 989
 990                 switch(c){
 991
 992                 case 's': /* DHCP server address */
 993                         if(inet_aton(optarg,&ipaddress))
 994                                 add_requested_server(ipaddress);
 995                         /*
 996                         else
 997                                 usage("Invalid server IP address\n");
 998                         */
 999                         break;
1000
1001                 case 'r': /* address we are requested from DHCP servers */
1002                         if(inet_aton(optarg,&ipaddress)){
1003                                 requested_address=ipaddress;
1004                                 request_specific_address=TRUE;
1005                                 }
1006                         /*
1007                         else
1008                                 usage("Invalid requested IP address\n");
1009                         */
1010                         break;
1011
1012                 case 't': /* timeout */
1013
1014                         /*
1015                         if(is_intnonneg(optarg))
1016                         */
1017                         if(atoi(optarg)>0)
1018                                 dhcpoffer_timeout=atoi(optarg);
1019                         /*
1020                         else
1021                                 usage("Time interval must be a nonnegative integer\n");
1022                         */
1023                         break;
1024
1025                 case 'i': /* interface name */
1026
1027                         strncpy(network_interface_name,optarg,sizeof(network_interface_name)-1);
1028                         network_interface_name[sizeof(network_interface_name)-1]='\x0';
1029
1030                         break;
1031
1032                 case 'V': /* version */
1033
1034                         /*print_revision(progname,"$Revision$");*/
1035                         exit(STATE_OK);
1036
1037                 case 'h': /* help */
1038
1039                         print_help();
1040                         exit(STATE_OK);
1041
1042                 case '?': /* help */
1043
1044                         /*usage("Invalid argument\n");*/
1045                         break;
1046
1047                 default:
1048                         break;
1049                         }
1050                 }
1051
1052         return i;
1053         }
1054
1055
1056
1057 int validate_arguments(void){
1058
1059         return OK;
1060         }
1061