/****************************************************************************** * * CHECK_SMTP.C * * Program: SMTP plugin for Nagios * License: GPL * Copyright (c) 1999 Ethan Galstad (nagios@nagios.org) * * $Id$ * * Description: * * This plugin will attempt to open an SMTP connection with the host. * Successul connects return STATE_OK, refusals and timeouts return * STATE_CRITICAL, other errors return STATE_UNKNOWN. Successful * connects, but incorrect reponse messages from the host result in * STATE_WARNING return values. * * License Information: * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. * *****************************************************************************/ #include "config.h" #include "common.h" #include "netutils.h" #include "utils.h" const char *progname = "check_smtp"; #define SMTP_PORT 25 #define SMTP_EXPECT "220" #define SMTP_HELO "HELO " /* sendmail will syslog a "NOQUEUE" error if session does not attempt * to do something useful. This can be prevented by giving a command * even if syntax is illegal (MAIL requires a FROM:<...> argument) * You can disable sending DUMMYCMD by undefining SMTP_USE_DUMMYCMD. * * According to rfc821 you can include a null reversepath in the from command * - but a log message is generated on the smtp server. * * Use the -f option to provide a FROM address */ #define SMTP_DUMMYCMD "MAIL " #define SMTP_USE_DUMMYCMD 1 #define SMTP_QUIT "QUIT\r\n" int process_arguments (int, char **); int validate_arguments (void); void print_help (void); void print_usage (void); int server_port = SMTP_PORT; char *server_address = NULL; char *server_expect = NULL; char *from_arg = " "; int warning_time = 0; int check_warning_time = FALSE; int critical_time = 0; int check_critical_time = FALSE; int verbose = FALSE; int main (int argc, char **argv) { int sd; int result = STATE_UNKNOWN; char buffer[MAX_INPUT_BUFFER] = ""; char *from_str = NULL; char *helocmd = NULL; if (process_arguments (argc, argv) != OK) usage ("Invalid command arguments supplied\n"); /* initialize the HELO command with the localhostname */ #ifndef HOST_MAX_BYTES #define HOST_MAX_BYTES 255 #endif helocmd = malloc (HOST_MAX_BYTES); gethostname(helocmd, HOST_MAX_BYTES); asprintf (&helocmd, "%s%s%s", SMTP_HELO, helocmd, "\r\n"); /* initialize the MAIL command with optional FROM command */ asprintf (&from_str, "%sFROM: %s%s", SMTP_DUMMYCMD, from_arg, "\r\n"); if (verbose == TRUE) printf ("FROMCMD: %s\n", from_str); /* initialize alarm signal handling */ signal (SIGALRM, socket_timeout_alarm_handler); /* set socket timeout */ alarm (socket_timeout); /* try to connect to the host at the given port number */ time (&start_time); result = my_tcp_connect (server_address, server_port, &sd); /* we connected, so close connection before exiting */ if (result == STATE_OK) { /* watch for the SMTP connection string and */ /* return a WARNING status if we couldn't read any data */ if (recv (sd, buffer, MAX_INPUT_BUFFER - 1, 0) == -1) { printf ("recv() failed\n"); result = STATE_WARNING; } else { /* strip the buffer of carriage returns */ strip (buffer); /* make sure we find the response we are looking for */ if (!strstr (buffer, server_expect)) { if (server_port == SMTP_PORT) printf ("Invalid SMTP response received from host\n"); else printf ("Invalid SMTP response received from host on port %d\n", server_port); result = STATE_WARNING; } } /* send the HELO command */ send(sd, helocmd, strlen(helocmd), 0); /* allow for response to helo command to reach us */ recv(sd, buffer, MAX_INPUT_BUFFER-1, 0); #ifdef SMTP_USE_DUMMYCMD send(sd, from_str, strlen(from_str), 0); /* allow for response to DUMMYCMD to reach us */ recv(sd, buffer, MAX_INPUT_BUFFER-1, 0); if (verbose == TRUE) printf("DUMMYCMD: %s\n%s\n",from_str,buffer); #endif /* SMTP_USE_DUMMYCMD */ /* tell the server we're done */ send (sd, SMTP_QUIT, strlen (SMTP_QUIT), 0); /* finally close the connection */ close (sd); } /* reset the alarm */ alarm (0); time (&end_time); if (check_critical_time == TRUE && (end_time - start_time) > critical_time) result = STATE_CRITICAL; else if (check_warning_time == TRUE && (end_time - start_time) > warning_time) result = STATE_WARNING; if (verbose == TRUE) printf ("SMTP %s - %d sec. response time, %s\n", state_text (result), (int) (end_time - start_time), buffer); else printf ("SMTP %s - %d second response time\n", state_text (result), (int) (end_time - start_time)); return result; } /* process command-line arguments */ int process_arguments (int argc, char **argv) { int c; #ifdef HAVE_GETOPT_H int option_index = 0; static struct option long_options[] = { {"hostname", required_argument, 0, 'H'}, {"expect", required_argument, 0, 'e'}, {"critical", required_argument, 0, 'c'}, {"warning", required_argument, 0, 'w'}, {"port", required_argument, 0, 'p'}, {"from", required_argument, 0, 'f'}, {"verbose", no_argument, 0, 'v'}, {"version", no_argument, 0, 'V'}, {"help", no_argument, 0, 'h'}, {0, 0, 0, 0} }; #endif if (argc < 2) return ERROR; for (c = 1; c < argc; c++) { if (strcmp ("-to", argv[c]) == 0) strcpy (argv[c], "-t"); else if (strcmp ("-wt", argv[c]) == 0) strcpy (argv[c], "-w"); else if (strcmp ("-ct", argv[c]) == 0) strcpy (argv[c], "-c"); } while (1) { #ifdef HAVE_GETOPT_H c = getopt_long (argc, argv, "+hVvt:p:f:e:c:w:H:", long_options, &option_index); #else c = getopt (argc, argv, "+?hVvt:p:f:e:c:w:H:"); #endif if (c == -1 || c == EOF) break; switch (c) { case 'H': /* hostname */ if (is_host (optarg)) { server_address = optarg; } else { usage ("Invalid host name\n"); } break; case 'p': /* port */ if (is_intpos (optarg)) { server_port = atoi (optarg); } else { usage ("Server port must be a positive integer\n"); } break; case 'f': /* from argument */ from_arg = optarg; break; case 'e': /* server expect string on 220 */ server_expect = optarg; break; case 'c': /* critical time threshold */ if (is_intnonneg (optarg)) { critical_time = atoi (optarg); check_critical_time = TRUE; } else { usage ("Critical time must be a nonnegative integer\n"); } break; case 'w': /* warning time threshold */ if (is_intnonneg (optarg)) { warning_time = atoi (optarg); check_warning_time = TRUE; } else { usage ("Warning time must be a nonnegative integer\n"); } break; case 'v': /* verbose */ verbose = TRUE; break; case 't': /* timeout */ if (is_intnonneg (optarg)) { socket_timeout = atoi (optarg); } else { usage ("Time interval must be a nonnegative integer\n"); } break; case 'V': /* version */ print_revision (progname, "$Revision$"); exit (STATE_OK); case 'h': /* help */ print_help (); exit (STATE_OK); case '?': /* help */ usage ("Invalid argument\n"); } } c = optind; if (server_address == NULL) { if (argv[c]) { if (is_host (argv[c])) server_address = argv[c]; else usage ("Invalid host name"); } else { asprintf (&server_address, "127.0.0.1"); } } if (server_expect == NULL) asprintf (&server_expect, SMTP_EXPECT); return validate_arguments (); } int validate_arguments (void) { return OK; } void print_help (void) { print_revision (progname, "$Revision$"); printf ("Copyright (c) 2000 Ethan Galstad/Karl DeBisschop\n\n" "This plugin test the SMTP service on the specified host.\n\n"); print_usage (); printf ("\nOptions:\n" " -H, --hostname=STRING or IPADDRESS\n" " Check server on the indicated host\n" " -p, --port=INTEGER\n" " Make connection on the indicated port (default: %d)\n" " -e, --expect=STRING\n" " String to expect in first line of server response (default: %s)\n" " -f, --from=STRING\n" " from address to include in MAIL command (default NULL, Exchange2000 requires one)\n" " -w, --warning=INTEGER\n" " Seconds necessary to result in a warning status\n" " -c, --critical=INTEGER\n" " Seconds necessary to result in a critical status\n" " -t, --timeout=INTEGER\n" " Seconds before connection attempt times out (default: %d)\n" " -v, --verbose\n" " Print extra information (command-line use only)\n" " -h, --help\n" " Print detailed help screen\n" " -V, --version\n" " Print version information\n\n", SMTP_PORT, SMTP_EXPECT, DEFAULT_SOCKET_TIMEOUT); support (); } void print_usage (void) { printf ("Usage: %s -H host [-e expect] [-p port] [-f from addr] [-w warn] [-c crit] [-t timeout] [-v]\n" " %s --help\n" " %s --version\n", progname, progname, progname); }