/***************************************************************************** * * Monitoring check_dhcp plugin * * License: GPL * Copyright (c) 2001-2004 Ethan Galstad (nagios@nagios.org) * Copyright (c) 2001-2023 Monitoring Plugins Development Team * * Description: * * This file contains the check_dhcp plugin * * This plugin tests the availability of DHCP servers on a network. * * Unicast mode was originally implemented by Heiti of Boras Kommun with * general improvements as well as usability fixes and "forward"-porting by * Andreas Ericsson of OP5 AB. * * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see . * * *****************************************************************************/ const char *progname = "check_dhcp"; const char *copyright = "2001-2024"; const char *email = "devel@monitoring-plugins.org"; #include "common.h" #include "netutils.h" #include "utils.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #if HAVE_SYS_SOCKIO_H # include #endif // HAVE_SYS_SOCKIO_H #if defined(__linux__) # include # include #elif defined(__bsd__) # include # include # include # include #elif defined(__sun__) || defined(__solaris__) || defined(__hpux__) # define INSAP 22 # define OUTSAP 24 # include # include # include # include # include # define bcopy(source, destination, length) memcpy(destination, source, length) # define AREA_SZ 5000 /* buffer length in bytes */ static u_long ctl_area[AREA_SZ]; static u_long dat_area[AREA_SZ]; static struct strbuf ctl = {AREA_SZ, 0, (char *)ctl_area}; static struct strbuf dat = {AREA_SZ, 0, (char *)dat_area}; # define GOT_CTRL 1 # define GOT_DATA 2 # define GOT_BOTH 3 # define GOT_INTR 4 # define GOT_ERR 128 static int get_msg(int); static int check_ctrl(int); static int put_ctrl(int, int, int); static int put_both(int, int, int, int); static int dl_open(const char *, int, int *); static int dl_bind(int, int, u_char *); long mac_addr_dlpi(const char *, int, u_char *); #endif // __sun__ || __solaris__ || __hpux /**** Common definitions ****/ #define OK 0 #define ERROR -1 /**** DHCP definitions ****/ #define MAX_DHCP_CHADDR_LENGTH 16 #define MAX_DHCP_SNAME_LENGTH 64 #define MAX_DHCP_FILE_LENGTH 128 #define MAX_DHCP_OPTIONS_LENGTH 312 typedef struct dhcp_packet_struct { uint8_t op; /* packet type */ uint8_t htype; /* type of hardware address for this machine (Ethernet, etc) */ uint8_t hlen; /* length of hardware address (of this machine) */ uint8_t hops; /* hops */ uint32_t xid; /* random transaction id number - chosen by this machine */ uint16_t secs; /* seconds used in timing */ uint16_t flags; /* flags */ struct in_addr ciaddr; /* IP address of this machine (if we already have one) */ struct in_addr yiaddr; /* IP address of this machine (offered by the DHCP server) */ struct in_addr siaddr; /* IP address of next server */ struct in_addr giaddr; /* IP address of DHCP relay */ unsigned char chaddr[MAX_DHCP_CHADDR_LENGTH]; /* hardware address of this machine */ char sname[MAX_DHCP_SNAME_LENGTH]; /* name of DHCP server */ char file[MAX_DHCP_FILE_LENGTH]; /* boot file name (used for diskless booting?) */ char options[MAX_DHCP_OPTIONS_LENGTH]; /* options */ } dhcp_packet; typedef struct dhcp_offer_struct { struct in_addr server_address; /* address of DHCP server that sent this offer */ struct in_addr offered_address; /* the IP address that was offered to us */ uint32_t lease_time; /* lease time in seconds */ uint32_t renewal_time; /* renewal time in seconds */ uint32_t rebinding_time; /* rebinding time in seconds */ bool desired; /* is this offer desired (necessary in exclusive mode) */ struct dhcp_offer_struct *next; } dhcp_offer; typedef struct requested_server_struct { struct in_addr server_address; bool answered; struct requested_server_struct *next; } requested_server; #define BOOTREQUEST 1 #define BOOTREPLY 2 #define DHCPDISCOVER 1 #define DHCPOFFER 2 #define DHCPREQUEST 3 #define DHCPDECLINE 4 #define DHCPACK 5 #define DHCPNACK 6 #define DHCPRELEASE 7 #define DHCP_OPTION_MESSAGE_TYPE 53 #define DHCP_OPTION_HOST_NAME 12 #define DHCP_OPTION_BROADCAST_ADDRESS 28 #define DHCP_OPTION_REQUESTED_ADDRESS 50 #define DHCP_OPTION_LEASE_TIME 51 #define DHCP_OPTION_SERVER_IDENTIFIER 54 #define DHCP_OPTION_RENEWAL_TIME 58 #define DHCP_OPTION_REBINDING_TIME 59 #define DHCP_OPTION_END 255 #define DHCP_INFINITE_TIME 0xFFFFFFFF #define DHCP_BROADCAST_FLAG 32768 #define DHCP_SERVER_PORT 67 #define DHCP_CLIENT_PORT 68 #define ETHERNET_HARDWARE_ADDRESS 1 /* used in htype field of dhcp packet */ #define ETHERNET_HARDWARE_ADDRESS_LENGTH 6 /* length of Ethernet hardware addresses */ bool unicast = false; /* unicast mode: mimic a DHCP relay */ bool exclusive = false; /* exclusive mode aka "rogue DHCP server detection" */ struct in_addr my_ip; /* our address (required for relay) */ struct in_addr dhcp_ip; /* server to query (if in unicast mode) */ unsigned char client_hardware_address[MAX_DHCP_CHADDR_LENGTH] = ""; unsigned char *user_specified_mac = NULL; char network_interface_name[IFNAMSIZ] = "eth0"; uint32_t packet_xid = 0; uint32_t dhcp_lease_time = 0; uint32_t dhcp_renewal_time = 0; uint32_t dhcp_rebinding_time = 0; int dhcpoffer_timeout = 2; dhcp_offer *dhcp_offer_list = NULL; requested_server *requested_server_list = NULL; int valid_responses = 0; /* number of valid DHCPOFFERs we received */ int requested_servers = 0; int requested_responses = 0; bool request_specific_address = false; bool received_requested_address = false; int verbose = 0; struct in_addr requested_address; int process_arguments(int, char **); int call_getopt(int, char **); int validate_arguments(int); void print_usage(void); void print_help(void); void resolve_host(const char *in, struct in_addr *out); unsigned char *mac_aton(const char *); void print_hardware_address(const unsigned char *); int get_hardware_address(int, char *); int get_ip_address(int, char *); int send_dhcp_discover(int); int get_dhcp_offer(int); int get_results(void); int add_dhcp_offer(struct in_addr, dhcp_packet *); int free_dhcp_offer_list(void); int free_requested_server_list(void); int create_dhcp_socket(void); int close_dhcp_socket(int); int send_dhcp_packet(void *, int, int, struct sockaddr_in *); int receive_dhcp_packet(void *, int, int, int, struct sockaddr_in *); int main(int argc, char **argv) { int dhcp_socket; int result = STATE_UNKNOWN; setlocale(LC_ALL, ""); bindtextdomain(PACKAGE, LOCALEDIR); textdomain(PACKAGE); /* Parse extra opts if any */ argv = np_extra_opts(&argc, argv, progname); if (process_arguments(argc, argv) != OK) { usage4(_("Could not parse arguments")); } /* create socket for DHCP communications */ dhcp_socket = create_dhcp_socket(); /* get hardware address of client machine */ if (user_specified_mac != NULL) memcpy(client_hardware_address, user_specified_mac, 6); else get_hardware_address(dhcp_socket, network_interface_name); if (unicast) /* get IP address of client machine */ get_ip_address(dhcp_socket, network_interface_name); /* send DHCPDISCOVER packet */ send_dhcp_discover(dhcp_socket); /* wait for a DHCPOFFER packet */ get_dhcp_offer(dhcp_socket); /* close socket we created */ close_dhcp_socket(dhcp_socket); /* determine state/plugin output to return */ result = get_results(); /* free allocated memory */ free_dhcp_offer_list(); free_requested_server_list(); return result; } /* determines hardware address on client machine */ int get_hardware_address(int sock, char *interface_name) { #if defined(__linux__) struct ifreq ifr; strncpy((char *)&ifr.ifr_name, interface_name, sizeof(ifr.ifr_name) - 1); ifr.ifr_name[sizeof(ifr.ifr_name) - 1] = '\0'; /* try and grab hardware address of requested interface */ if (ioctl(sock, SIOCGIFHWADDR, &ifr) < 0) { printf(_("Error: Could not get hardware address of interface '%s'\n"), interface_name); exit(STATE_UNKNOWN); } memcpy(&client_hardware_address[0], &ifr.ifr_hwaddr.sa_data, 6); #elif defined(__bsd__) /* King 2004 see ACKNOWLEDGEMENTS */ size_t len; int mib[6]; char *buf; unsigned char *ptr; struct if_msghdr *ifm; struct sockaddr_dl *sdl; mib[0] = CTL_NET; mib[1] = AF_ROUTE; mib[2] = 0; mib[3] = AF_LINK; mib[4] = NET_RT_IFLIST; if ((mib[5] = if_nametoindex(interface_name)) == 0) { printf(_("Error: if_nametoindex error - %s.\n"), strerror(errno)); exit(STATE_UNKNOWN); } if (sysctl(mib, 6, NULL, &len, NULL, 0) < 0) { printf(_("Error: Couldn't get hardware address from %s. sysctl 1 error - %s.\n"), interface_name, strerror(errno)); exit(STATE_UNKNOWN); } if ((buf = malloc(len)) == NULL) { printf(_("Error: Couldn't get hardware address from interface %s. malloc error - %s.\n"), interface_name, strerror(errno)); exit(4); } if (sysctl(mib, 6, buf, &len, NULL, 0) < 0) { printf(_("Error: Couldn't get hardware address from %s. sysctl 2 error - %s.\n"), interface_name, strerror(errno)); exit(STATE_UNKNOWN); } ifm = (struct if_msghdr *)buf; sdl = (struct sockaddr_dl *)(ifm + 1); ptr = (unsigned char *)LLADDR(sdl); memcpy(&client_hardware_address[0], ptr, 6); /* King 2004 */ #elif defined(__sun__) || defined(__solaris__) /* Kompf 2000-2003 see ACKNOWLEDGEMENTS */ long stat; char dev[20] = "/dev/"; char *p; int unit; /* get last number from interfacename, eg lnc0, e1000g0*/ int i; p = interface_name + strlen(interface_name) - 1; for (i = strlen(interface_name) - 1; i > 0; p--) { if (isalpha(*p)) break; } p++; if (p != interface_name) { unit = atoi(p); strncat(dev, interface_name, 6); } else { printf(_("Error: can't find unit number in interface_name (%s) - expecting TypeNumber eg lnc0.\n"), interface_name); exit(STATE_UNKNOWN); } stat = mac_addr_dlpi(dev, unit, client_hardware_address); if (stat != 0) { printf(_("Error: can't read MAC address from DLPI streams interface for device %s unit %d.\n"), dev, unit); exit(STATE_UNKNOWN); } #elif defined(__hpux__) long stat; char dev[20] = "/dev/dlpi"; int unit = 0; stat = mac_addr_dlpi(dev, unit, client_hardware_address); if (stat != 0) { printf(_("Error: can't read MAC address from DLPI streams interface for device %s unit %d.\n"), dev, unit); exit(STATE_UNKNOWN); } /* Kompf 2000-2003 */ #else printf(_("Error: can't get MAC address for this architecture. Use the --mac option.\n")); exit(STATE_UNKNOWN); #endif if (verbose) print_hardware_address(client_hardware_address); return OK; } /* determines IP address of the client interface */ int get_ip_address(int sock, char *interface_name) { #if defined(SIOCGIFADDR) struct ifreq ifr; strncpy((char *)&ifr.ifr_name, interface_name, sizeof(ifr.ifr_name) - 1); ifr.ifr_name[sizeof(ifr.ifr_name) - 1] = '\0'; if (ioctl(sock, SIOCGIFADDR, &ifr) < 0) { printf(_("Error: Cannot determine IP address of interface %s\n"), interface_name); exit(STATE_UNKNOWN); } my_ip = ((struct sockaddr_in *)&ifr.ifr_addr)->sin_addr; #else printf(_("Error: Cannot get interface IP address on this platform.\n")); exit(STATE_UNKNOWN); #endif if (verbose) printf(_("Pretending to be relay client %s\n"), inet_ntoa(my_ip)); return OK; } /* sends a DHCPDISCOVER broadcast message in an attempt to find DHCP servers */ int send_dhcp_discover(int sock) { dhcp_packet discover_packet; struct sockaddr_in sockaddr_broadcast; unsigned short opts; /* clear the packet data structure */ bzero(&discover_packet, sizeof(discover_packet)); /* boot request flag (backward compatible with BOOTP servers) */ discover_packet.op = BOOTREQUEST; /* hardware address type */ discover_packet.htype = ETHERNET_HARDWARE_ADDRESS; /* length of our hardware address */ discover_packet.hlen = ETHERNET_HARDWARE_ADDRESS_LENGTH; /* * transaction ID is supposed to be random. */ srand(time(NULL) ^ getpid()); packet_xid = random(); discover_packet.xid = htonl(packet_xid); /*discover_packet.secs=htons(65535);*/ discover_packet.secs = 0xFF; /* * server needs to know if it should broadcast or unicast its response: * 0x8000L == 32768 == 1 << 15 == broadcast, 0 == unicast */ discover_packet.flags = unicast ? 0 : htons(DHCP_BROADCAST_FLAG); /* our hardware address */ memcpy(discover_packet.chaddr, client_hardware_address, ETHERNET_HARDWARE_ADDRESS_LENGTH); /* first four bytes of options field is magic cookie (as per RFC 2132) */ discover_packet.options[0] = '\x63'; discover_packet.options[1] = '\x82'; discover_packet.options[2] = '\x53'; discover_packet.options[3] = '\x63'; opts = 4; /* DHCP message type is embedded in options field */ discover_packet.options[opts++] = DHCP_OPTION_MESSAGE_TYPE; /* DHCP message type option identifier */ discover_packet.options[opts++] = '\x01'; /* DHCP message option length in bytes */ discover_packet.options[opts++] = DHCPDISCOVER; /* the IP address we're requesting */ if (request_specific_address) { discover_packet.options[opts++] = DHCP_OPTION_REQUESTED_ADDRESS; discover_packet.options[opts++] = '\x04'; memcpy(&discover_packet.options[opts], &requested_address, sizeof(requested_address)); opts += sizeof(requested_address); } discover_packet.options[opts++] = (char)DHCP_OPTION_END; /* unicast fields */ if (unicast) discover_packet.giaddr.s_addr = my_ip.s_addr; /* see RFC 1542, 4.1.1 */ discover_packet.hops = unicast ? 1 : 0; /* send the DHCPDISCOVER packet to broadcast address */ sockaddr_broadcast.sin_family = AF_INET; sockaddr_broadcast.sin_port = htons(DHCP_SERVER_PORT); sockaddr_broadcast.sin_addr.s_addr = unicast ? dhcp_ip.s_addr : INADDR_BROADCAST; bzero(&sockaddr_broadcast.sin_zero, sizeof(sockaddr_broadcast.sin_zero)); if (verbose) { printf(_("DHCPDISCOVER to %s port %d\n"), inet_ntoa(sockaddr_broadcast.sin_addr), ntohs(sockaddr_broadcast.sin_port)); printf("DHCPDISCOVER XID: %u (0x%X)\n", ntohl(discover_packet.xid), ntohl(discover_packet.xid)); printf("DHCDISCOVER ciaddr: %s\n", inet_ntoa(discover_packet.ciaddr)); printf("DHCDISCOVER yiaddr: %s\n", inet_ntoa(discover_packet.yiaddr)); printf("DHCDISCOVER siaddr: %s\n", inet_ntoa(discover_packet.siaddr)); printf("DHCDISCOVER giaddr: %s\n", inet_ntoa(discover_packet.giaddr)); } /* send the DHCPDISCOVER packet out */ send_dhcp_packet(&discover_packet, sizeof(discover_packet), sock, &sockaddr_broadcast); if (verbose) printf("\n\n"); return OK; } /* waits for a DHCPOFFER message from one or more DHCP servers */ int get_dhcp_offer(int sock) { dhcp_packet offer_packet; struct sockaddr_in source; struct sockaddr_in via; int result = OK; int responses = 0; int x; time_t start_time; time_t current_time; time(&start_time); /* receive as many responses as we can */ for (responses = 0, valid_responses = 0;;) { time(¤t_time); if ((current_time - start_time) >= dhcpoffer_timeout) break; if (verbose) printf("\n\n"); bzero(&source, sizeof(source)); bzero(&via, sizeof(via)); bzero(&offer_packet, sizeof(offer_packet)); result = OK; result = receive_dhcp_packet(&offer_packet, sizeof(offer_packet), sock, dhcpoffer_timeout, &source); if (result != OK) { if (verbose) printf(_("Result=ERROR\n")); continue; } else { if (verbose) printf(_("Result=OK\n")); responses++; } /* The "source" is either a server or a relay. */ /* Save a copy of "source" into "via" even if it's via itself */ memcpy(&via, &source, sizeof(source)); if (verbose) { printf(_("DHCPOFFER from IP address %s"), inet_ntoa(source.sin_addr)); printf(_(" via %s\n"), inet_ntoa(via.sin_addr)); printf("DHCPOFFER XID: %u (0x%X)\n", ntohl(offer_packet.xid), ntohl(offer_packet.xid)); } /* check packet xid to see if its the same as the one we used in the discover packet */ if (ntohl(offer_packet.xid) != packet_xid) { if (verbose) printf(_("DHCPOFFER XID (%u) did not match DHCPDISCOVER XID (%u) - ignoring packet\n"), ntohl(offer_packet.xid), packet_xid); continue; } /* check hardware address */ result = OK; if (verbose) printf("DHCPOFFER chaddr: "); for (x = 0; x < ETHERNET_HARDWARE_ADDRESS_LENGTH; x++) { if (verbose) printf("%02X", (unsigned char)offer_packet.chaddr[x]); if (offer_packet.chaddr[x] != client_hardware_address[x]) result = ERROR; } if (verbose) printf("\n"); if (result == ERROR) { if (verbose) printf(_("DHCPOFFER hardware address did not match our own - ignoring packet\n")); continue; } if (verbose) { printf("DHCPOFFER ciaddr: %s\n", inet_ntoa(offer_packet.ciaddr)); printf("DHCPOFFER yiaddr: %s\n", inet_ntoa(offer_packet.yiaddr)); printf("DHCPOFFER siaddr: %s\n", inet_ntoa(offer_packet.siaddr)); printf("DHCPOFFER giaddr: %s\n", inet_ntoa(offer_packet.giaddr)); } add_dhcp_offer(source.sin_addr, &offer_packet); valid_responses++; } if (verbose) { printf(_("Total responses seen on the wire: %d\n"), responses); printf(_("Valid responses for this machine: %d\n"), valid_responses); } return OK; } /* sends a DHCP packet */ int send_dhcp_packet(void *buffer, int buffer_size, int sock, struct sockaddr_in *dest) { int result; result = sendto(sock, (char *)buffer, buffer_size, 0, (struct sockaddr *)dest, sizeof(*dest)); if (verbose) printf(_("send_dhcp_packet result: %d\n"), result); if (result < 0) return ERROR; return OK; } /* receives a DHCP packet */ int receive_dhcp_packet(void *buffer, int buffer_size, int sock, int timeout, struct sockaddr_in *address) { struct timeval tv; fd_set readfds; fd_set oobfds; int recv_result; socklen_t address_size; struct sockaddr_in source_address; int nfound; /* wait for data to arrive (up time timeout) */ tv.tv_sec = timeout; tv.tv_usec = 0; FD_ZERO(&readfds); FD_ZERO(&oobfds); FD_SET(sock, &readfds); FD_SET(sock, &oobfds); nfound = select(sock + 1, &readfds, NULL, &oobfds, &tv); /* make sure some data has arrived */ if (!FD_ISSET(sock, &readfds)) { if (verbose) printf(_("No (more) data received (nfound: %d)\n"), nfound); return ERROR; } else { bzero(&source_address, sizeof(source_address)); address_size = sizeof(source_address); recv_result = recvfrom(sock, (char *)buffer, buffer_size, 0, (struct sockaddr *)&source_address, &address_size); if (verbose) printf("recv_result: %d\n", recv_result); if (recv_result == -1) { if (verbose) { printf(_("recvfrom() failed, ")); printf("errno: (%d) -> %s\n", errno, strerror(errno)); } return ERROR; } else { if (verbose) { printf(_("receive_dhcp_packet() result: %d\n"), recv_result); printf(_("receive_dhcp_packet() source: %s\n"), inet_ntoa(source_address.sin_addr)); } memcpy(address, &source_address, sizeof(source_address)); return OK; } } return OK; } /* creates a socket for DHCP communication */ int create_dhcp_socket(void) { struct sockaddr_in myname; struct ifreq interface; int sock; int flag = 1; /* Set up the address we're going to bind to. */ bzero(&myname, sizeof(myname)); myname.sin_family = AF_INET; /* listen to DHCP server port if we're in unicast mode */ myname.sin_port = htons(unicast ? DHCP_SERVER_PORT : DHCP_CLIENT_PORT); myname.sin_addr.s_addr = unicast ? my_ip.s_addr : INADDR_ANY; bzero(&myname.sin_zero, sizeof(myname.sin_zero)); /* create a socket for DHCP communications */ sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP); if (sock < 0) { printf(_("Error: Could not create socket!\n")); exit(STATE_UNKNOWN); } if (verbose) printf("DHCP socket: %d\n", sock); /* set the reuse address flag so we don't get errors when restarting */ flag = 1; if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (char *)&flag, sizeof(flag)) < 0) { printf(_("Error: Could not set reuse address option on DHCP socket!\n")); exit(STATE_UNKNOWN); } /* set the broadcast option - we need this to listen to DHCP broadcast messages */ if (!unicast && setsockopt(sock, SOL_SOCKET, SO_BROADCAST, (char *)&flag, sizeof flag) < 0) { printf(_("Error: Could not set broadcast option on DHCP socket!\n")); exit(STATE_UNKNOWN); } /* bind socket to interface */ #if defined(__linux__) strncpy(interface.ifr_ifrn.ifrn_name, network_interface_name, IFNAMSIZ - 1); interface.ifr_ifrn.ifrn_name[IFNAMSIZ - 1] = '\0'; if (setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, (char *)&interface, sizeof(interface)) < 0) { printf(_("Error: Could not bind socket to interface %s. Check your privileges...\n"), network_interface_name); exit(STATE_UNKNOWN); } #else strncpy(interface.ifr_name, network_interface_name, IFNAMSIZ - 1); interface.ifr_name[IFNAMSIZ - 1] = '\0'; #endif /* bind the socket */ if (bind(sock, (struct sockaddr *)&myname, sizeof(myname)) < 0) { printf(_("Error: Could not bind to DHCP socket (port %d)! Check your privileges...\n"), DHCP_CLIENT_PORT); exit(STATE_UNKNOWN); } return sock; } /* closes DHCP socket */ int close_dhcp_socket(int sock) { close(sock); return OK; } /* adds a requested server address to list in memory */ int add_requested_server(struct in_addr server_address) { requested_server *new_server; new_server = (requested_server *)malloc(sizeof(requested_server)); if (new_server == NULL) return ERROR; new_server->server_address = server_address; new_server->answered = false; new_server->next = requested_server_list; requested_server_list = new_server; requested_servers++; if (verbose) printf(_("Requested server address: %s\n"), inet_ntoa(new_server->server_address)); return OK; } /* adds a DHCP OFFER to list in memory */ int add_dhcp_offer(struct in_addr source, dhcp_packet *offer_packet) { dhcp_offer *new_offer; int x; unsigned option_type; unsigned option_length; struct in_addr serv_ident = {0}; if (offer_packet == NULL) return ERROR; /* process all DHCP options present in the packet */ for (x = 4; x < MAX_DHCP_OPTIONS_LENGTH - 1;) { if ((int)offer_packet->options[x] == -1) break; /* get option type */ option_type = offer_packet->options[x++]; /* get option length */ option_length = offer_packet->options[x++]; if (verbose) printf("Option: %d (0x%02X)\n", option_type, option_length); /* get option data */ switch (option_type) { case DHCP_OPTION_LEASE_TIME: memcpy(&dhcp_lease_time, &offer_packet->options[x], sizeof(dhcp_lease_time)); dhcp_lease_time = ntohl(dhcp_lease_time); break; case DHCP_OPTION_RENEWAL_TIME: memcpy(&dhcp_renewal_time, &offer_packet->options[x], sizeof(dhcp_renewal_time)); dhcp_renewal_time = ntohl(dhcp_renewal_time); break; case DHCP_OPTION_REBINDING_TIME: memcpy(&dhcp_rebinding_time, &offer_packet->options[x], sizeof(dhcp_rebinding_time)); dhcp_rebinding_time = ntohl(dhcp_rebinding_time); break; case DHCP_OPTION_SERVER_IDENTIFIER: memcpy(&serv_ident.s_addr, &offer_packet->options[x], sizeof(serv_ident.s_addr)); break; } /* skip option data we're ignoring */ if (option_type == 0) /* "pad" option, see RFC 2132 (3.1) */ x += 1; else x += option_length; } if (verbose) { if (dhcp_lease_time == DHCP_INFINITE_TIME) printf(_("Lease Time: Infinite\n")); else printf(_("Lease Time: %lu seconds\n"), (unsigned long)dhcp_lease_time); if (dhcp_renewal_time == DHCP_INFINITE_TIME) printf(_("Renewal Time: Infinite\n")); else printf(_("Renewal Time: %lu seconds\n"), (unsigned long)dhcp_renewal_time); if (dhcp_rebinding_time == DHCP_INFINITE_TIME) printf(_("Rebinding Time: Infinite\n")); printf(_("Rebinding Time: %lu seconds\n"), (unsigned long)dhcp_rebinding_time); } new_offer = (dhcp_offer *)malloc(sizeof(dhcp_offer)); if (new_offer == NULL) return ERROR; /* * RFC 2131 (2.) says: "DHCP clarifies the interpretation of the * 'siaddr' field as the address of the server to use in the next step * of the client's bootstrap process. A DHCP server may return its own * address in the 'siaddr' field, if the server is prepared to supply * the next bootstrap service (e.g., delivery of an operating system * executable image). A DHCP server always returns its own address in * the 'server identifier' option." 'serv_ident' is the 'server * identifier' option, 'source' is the IP address we received the * DHCPOFFER from. If 'serv_ident' isn't available for some reason, we * use 'source'. */ new_offer->server_address = serv_ident.s_addr ? serv_ident : source; new_offer->offered_address = offer_packet->yiaddr; new_offer->lease_time = dhcp_lease_time; new_offer->renewal_time = dhcp_renewal_time; new_offer->rebinding_time = dhcp_rebinding_time; new_offer->desired = false; /* exclusive mode: we'll check that in get_results */ if (verbose) { printf(_("Added offer from server @ %s"), inet_ntoa(new_offer->server_address)); printf(_(" of IP address %s\n"), inet_ntoa(new_offer->offered_address)); } /* add new offer to head of list */ new_offer->next = dhcp_offer_list; dhcp_offer_list = new_offer; return OK; } /* frees memory allocated to DHCP OFFER list */ int free_dhcp_offer_list(void) { dhcp_offer *this_offer; dhcp_offer *next_offer; for (this_offer = dhcp_offer_list; this_offer != NULL; this_offer = next_offer) { next_offer = this_offer->next; free(this_offer); } return OK; } /* frees memory allocated to requested server list */ int free_requested_server_list(void) { requested_server *this_server; requested_server *next_server; for (this_server = requested_server_list; this_server != NULL; this_server = next_server) { next_server = this_server->next; free(this_server); } return OK; } /* gets state and plugin output to return */ int get_results(void) { dhcp_offer *temp_offer, *undesired_offer = NULL; requested_server *temp_server; int result; uint32_t max_lease_time = 0; received_requested_address = false; /* checks responses from requested servers */ requested_responses = 0; if (requested_servers > 0) { for (temp_server = requested_server_list; temp_server != NULL; temp_server = temp_server->next) { for (temp_offer = dhcp_offer_list; temp_offer != NULL; temp_offer = temp_offer->next) { /* get max lease time we were offered */ if (temp_offer->lease_time > max_lease_time || temp_offer->lease_time == DHCP_INFINITE_TIME) max_lease_time = temp_offer->lease_time; /* see if we got the address we requested */ if (!memcmp(&requested_address, &temp_offer->offered_address, sizeof(requested_address))) received_requested_address = true; /* see if the servers we wanted a response from talked to us or not */ if (!memcmp(&temp_offer->server_address, &temp_server->server_address, sizeof(temp_server->server_address))) { if (verbose) { printf(_("DHCP Server Match: Offerer=%s"), inet_ntoa(temp_offer->server_address)); printf(_(" Requested=%s"), inet_ntoa(temp_server->server_address)); if (temp_server->answered) printf(_(" (duplicate)")); printf(_("\n")); } if (!temp_server->answered) { requested_responses++; temp_server->answered = true; temp_offer->desired = true; } } } } /* exclusive mode: check for undesired offers */ for (temp_offer = dhcp_offer_list; temp_offer != NULL; temp_offer = temp_offer->next) { if (!temp_offer->desired) { undesired_offer = temp_offer; /* Checks only for the first undesired offer */ break; /* no further checks needed */ } } } /* else check and see if we got our requested address from any server */ else { for (temp_offer = dhcp_offer_list; temp_offer != NULL; temp_offer = temp_offer->next) { /* get max lease time we were offered */ if (temp_offer->lease_time > max_lease_time || temp_offer->lease_time == DHCP_INFINITE_TIME) max_lease_time = temp_offer->lease_time; /* see if we got the address we requested */ if (!memcmp(&requested_address, &temp_offer->offered_address, sizeof(requested_address))) received_requested_address = true; } } result = STATE_OK; if (valid_responses == 0) result = STATE_CRITICAL; else if (requested_servers > 0 && requested_responses == 0) result = STATE_CRITICAL; else if (requested_responses < requested_servers) result = STATE_WARNING; else if (request_specific_address && !received_requested_address) result = STATE_WARNING; if (exclusive && undesired_offer) result = STATE_CRITICAL; if (result == 0) /* garrett honeycutt 2005 */ printf("OK: "); else if (result == 1) printf("WARNING: "); else if (result == 2) printf("CRITICAL: "); else if (result == 3) printf("UNKNOWN: "); /* we didn't receive any DHCPOFFERs */ if (dhcp_offer_list == NULL) { printf(_("No DHCPOFFERs were received.\n")); return result; } printf(_("Received %d DHCPOFFER(s)"), valid_responses); if (exclusive && undesired_offer) { printf(_(", Rogue DHCP Server detected! Server %s"), inet_ntoa(undesired_offer->server_address)); printf(_(" offered %s \n"), inet_ntoa(undesired_offer->offered_address)); return result; } if (requested_servers > 0) printf(_(", %s%d of %d requested servers responded"), ((requested_responses < requested_servers) && requested_responses > 0) ? "only " : "", requested_responses, requested_servers); if (request_specific_address) printf(_(", requested address (%s) was %soffered"), inet_ntoa(requested_address), (received_requested_address) ? "" : _("not ")); printf(_(", max lease time = ")); if (max_lease_time == DHCP_INFINITE_TIME) printf(_("Infinity")); else printf("%lu sec", (unsigned long)max_lease_time); printf(".\n"); return result; } /* process command-line arguments */ int process_arguments(int argc, char **argv) { if (argc < 1) return ERROR; call_getopt(argc, argv); return validate_arguments(argc); } int call_getopt(int argc, char **argv) { extern int optind; int option_index = 0; static struct option long_options[] = {{"serverip", required_argument, 0, 's'}, {"requestedip", required_argument, 0, 'r'}, {"timeout", required_argument, 0, 't'}, {"interface", required_argument, 0, 'i'}, {"mac", required_argument, 0, 'm'}, {"unicast", no_argument, 0, 'u'}, {"exclusive", no_argument, 0, 'x'}, {"verbose", no_argument, 0, 'v'}, {"version", no_argument, 0, 'V'}, {"help", no_argument, 0, 'h'}, {0, 0, 0, 0}}; int c = 0; while (true) { c = getopt_long(argc, argv, "+hVvxt:s:r:t:i:m:u", long_options, &option_index); if (c == -1 || c == EOF || c == 1) break; switch (c) { case 's': /* DHCP server address */ resolve_host(optarg, &dhcp_ip); add_requested_server(dhcp_ip); break; case 'r': /* address we are requested from DHCP servers */ resolve_host(optarg, &requested_address); request_specific_address = true; break; case 't': /* timeout */ /* if(is_intnonneg(optarg)) */ if (atoi(optarg) > 0) dhcpoffer_timeout = atoi(optarg); /* else usage("Time interval must be a nonnegative integer\n"); */ break; case 'm': /* MAC address */ if ((user_specified_mac = mac_aton(optarg)) == NULL) usage("Cannot parse MAC address.\n"); if (verbose) print_hardware_address(user_specified_mac); break; case 'i': /* interface name */ strncpy(network_interface_name, optarg, sizeof(network_interface_name) - 1); network_interface_name[sizeof(network_interface_name) - 1] = '\x0'; break; case 'u': /* unicast testing */ unicast = true; break; case 'x': /* exclusive testing aka "rogue DHCP server detection" */ exclusive = true; break; case 'V': /* version */ print_revision(progname, NP_VERSION); exit(STATE_UNKNOWN); case 'h': /* help */ print_help(); exit(STATE_UNKNOWN); case 'v': /* verbose */ verbose = 1; break; case '?': /* help */ usage5(); break; default: break; } } return optind; } int validate_arguments(int argc) { if (argc - optind > 0) usage(_("Got unexpected non-option argument")); return OK; } #if defined(__sun__) || defined(__solaris__) || defined(__hpux__) /* Kompf 2000-2003 see ACKNOWLEDGEMENTS */ /* get a message from a stream; return type of message */ static int get_msg(int fd) { int flags = 0; int res, ret; ctl_area[0] = 0; dat_area[0] = 0; ret = 0; res = getmsg(fd, &ctl, &dat, &flags); if (res < 0) { if (errno == EINTR) { return (GOT_INTR); } else { printf("%s\n", "get_msg FAILED."); return (GOT_ERR); } } if (ctl.len > 0) { ret |= GOT_CTRL; } if (dat.len > 0) { ret |= GOT_DATA; } return (ret); } /* verify that dl_primitive in ctl_area = prim */ static int check_ctrl(int prim) { dl_error_ack_t *err_ack = (dl_error_ack_t *)ctl_area; if (err_ack->dl_primitive != prim) { printf(_("Error: DLPI stream API failed to get MAC in check_ctrl: %s.\n"), strerror(errno)); exit(STATE_UNKNOWN); } return 0; } /* put a control message on a stream */ static int put_ctrl(int fd, int len, int pri) { ctl.len = len; if (putmsg(fd, &ctl, 0, pri) < 0) { printf(_("Error: DLPI stream API failed to get MAC in put_ctrl/putmsg(): %s.\n"), strerror(errno)); exit(STATE_UNKNOWN); } return 0; } /* put a control + data message on a stream */ static int put_both(int fd, int clen, int dlen, int pri) { ctl.len = clen; dat.len = dlen; if (putmsg(fd, &ctl, &dat, pri) < 0) { printf(_("Error: DLPI stream API failed to get MAC in put_both/putmsg().\n"), strerror(errno)); exit(STATE_UNKNOWN); } return 0; } /* open file descriptor and attach */ static int dl_open(const char *dev, int unit, int *fd) { dl_attach_req_t *attach_req = (dl_attach_req_t *)ctl_area; if ((*fd = open(dev, O_RDWR)) == -1) { printf(_("Error: DLPI stream API failed to get MAC in dl_attach_req/open(%s..): %s.\n"), dev, strerror(errno)); exit(STATE_UNKNOWN); } attach_req->dl_primitive = DL_ATTACH_REQ; attach_req->dl_ppa = unit; put_ctrl(*fd, sizeof(dl_attach_req_t), 0); get_msg(*fd); return check_ctrl(DL_OK_ACK); } /* send DL_BIND_REQ */ static int dl_bind(int fd, int sap, u_char *addr) { dl_bind_req_t *bind_req = (dl_bind_req_t *)ctl_area; dl_bind_ack_t *bind_ack = (dl_bind_ack_t *)ctl_area; bind_req->dl_primitive = DL_BIND_REQ; bind_req->dl_sap = sap; bind_req->dl_max_conind = 1; bind_req->dl_service_mode = DL_CLDLS; bind_req->dl_conn_mgmt = 0; bind_req->dl_xidtest_flg = 0; put_ctrl(fd, sizeof(dl_bind_req_t), 0); get_msg(fd); if (GOT_ERR == check_ctrl(DL_BIND_ACK)) { printf(_("Error: DLPI stream API failed to get MAC in dl_bind/check_ctrl(): %s.\n"), strerror(errno)); exit(STATE_UNKNOWN); } bcopy((u_char *)bind_ack + bind_ack->dl_addr_offset, addr, bind_ack->dl_addr_length); return 0; } /*********************************************************************** * interface: * function mac_addr_dlpi - get the mac address of the interface with * type dev (eg lnc, hme) and unit (0, 1 ..) * * parameter: addr: an array of six bytes, has to be allocated by the caller * * return: 0 if OK, -1 if the address could not be determined * * ***********************************************************************/ long mac_addr_dlpi(const char *dev, int unit, u_char *addr) { int fd; u_char mac_addr[25]; if (GOT_ERR != dl_open(dev, unit, &fd)) { if (GOT_ERR != dl_bind(fd, INSAP, mac_addr)) { bcopy(mac_addr, addr, 6); return 0; } } close(fd); return -1; } /* Kompf 2000-2003 */ #endif /* resolve host name or die (TODO: move this to netutils.c!) */ void resolve_host(const char *in, struct in_addr *out) { struct addrinfo hints, *ai; memset(&hints, 0, sizeof(hints)); hints.ai_family = PF_INET; if (getaddrinfo(in, NULL, &hints, &ai) != 0) usage_va(_("Invalid hostname/address - %s"), optarg); memcpy(out, &((struct sockaddr_in *)ai->ai_addr)->sin_addr, sizeof(*out)); freeaddrinfo(ai); } /* parse MAC address string, return 6 bytes (unterminated) or NULL */ unsigned char *mac_aton(const char *string) { static unsigned char result[6]; char tmp[3]; unsigned i, j; for (i = 0, j = 0; string[i] != '\0' && j < sizeof(result); i++) { /* ignore ':' and any other non-hex character */ if (!isxdigit(string[i]) || !isxdigit(string[i + 1])) continue; tmp[0] = string[i]; tmp[1] = string[i + 1]; tmp[2] = '\0'; result[j] = strtol(tmp, (char **)NULL, 16); i++; j++; } return (j == 6) ? result : NULL; } void print_hardware_address(const unsigned char *address) { int i; printf(_("Hardware address: ")); for (i = 0; i < 5; i++) printf("%2.2x:", address[i]); printf("%2.2x", address[i]); putchar('\n'); } /* print usage help */ void print_help(void) { print_revision(progname, NP_VERSION); printf("Copyright (c) 2001-2004 Ethan Galstad (nagios@nagios.org)\n"); printf(COPYRIGHT, copyright, email); printf("%s\n", _("This plugin tests the availability of DHCP servers on a network.")); printf("\n\n"); print_usage(); printf(UT_HELP_VRSN); printf(UT_EXTRA_OPTS); printf(UT_VERBOSE); printf(" %s\n", "-s, --serverip=IPADDRESS"); printf(" %s\n", _("IP address of DHCP server that we must hear from")); printf(" %s\n", "-r, --requestedip=IPADDRESS"); printf(" %s\n", _("IP address that should be offered by at least one DHCP server")); printf(" %s\n", "-t, --timeout=INTEGER"); printf(" %s\n", _("Seconds to wait for DHCPOFFER before timeout occurs")); printf(" %s\n", "-i, --interface=STRING"); printf(" %s\n", _("Interface to to use for listening (i.e. eth0)")); printf(" %s\n", "-m, --mac=STRING"); printf(" %s\n", _("MAC address to use in the DHCP request")); printf(" %s\n", "-u, --unicast"); printf(" %s\n", _("Unicast testing: mimic a DHCP relay, requires -s")); printf(" %s\n", "-x, --exclusive"); printf(" %s\n", _("Only requested DHCP server may response (rogue DHCP server detection), requires -s")); printf(UT_SUPPORT); return; } void print_usage(void) { printf("%s\n", _("Usage:")); printf(" %s [-v] [-u] [-x] [-s serverip] [-r requestedip] [-t timeout]\n", progname); printf(" [-i interface] [-m mac]\n"); return; }