/*****************************************************************************
*
* 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;
}