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netutils.c

/*****************************************************************************
* 
* Nagios plugins network utilities
* 
* License: GPL
* Copyright (c) 1999 Ethan Galstad (nagios@nagios.org)
* Copyright (c) 2003-2008 Nagios Plugins Development Team
* 
* Last Modified: $Date: 2008-01-31 11:27:22 +0000 (Thu, 31 Jan 2008) $
* 
* Description:
* 
* This file contains commons functions used in many of the plugins.
* 
* 
* 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 <http://www.gnu.org/licenses/>.
* 
* $Id: netutils.c 1918 2008-01-31 11:27:22Z dermoth $
* 
*****************************************************************************/

#define LOCAL_TIMEOUT_ALARM_HANDLER

#include "common.h"
#include "netutils.h"

unsigned int socket_timeout = DEFAULT_SOCKET_TIMEOUT; 
int econn_refuse_state = STATE_CRITICAL;
int was_refused = FALSE;
#if USE_IPV6
int address_family = AF_UNSPEC;
#else
int address_family = AF_INET;
#endif

/* handles socket timeouts */
void
socket_timeout_alarm_handler (int sig)
{
      if (sig == SIGALRM)
            printf (_("CRITICAL - Socket timeout after %d seconds\n"), socket_timeout);
      else
            printf (_("CRITICAL - Abnormal timeout after %d seconds\n"), socket_timeout);

      exit (STATE_CRITICAL);
}


/* connects to a host on a specified tcp port, sends a string, and gets a 
       response. loops on select-recv until timeout or eof to get all of a 
       multi-packet answer */
int
process_tcp_request2 (const char *server_address, int server_port,
      const char *send_buffer, char *recv_buffer, int recv_size)
{

      int result;
      int send_result;
      int recv_result;
      int sd;
      struct timeval tv;
      fd_set readfds;
      int recv_length = 0;

      result = np_net_connect (server_address, server_port, &sd, IPPROTO_TCP);
      if (result != STATE_OK)
            return STATE_CRITICAL;

      send_result = send (sd, send_buffer, strlen (send_buffer), 0);
      if (send_result<0 || (size_t)send_result!=strlen(send_buffer)) {
            printf ("%s\n", _("Send failed"));
            result = STATE_WARNING;
      }

      while (1) {
            /* wait up to the number of seconds for socket timeout
               minus one for data from the host */
            tv.tv_sec = socket_timeout - 1;
            tv.tv_usec = 0;
            FD_ZERO (&readfds);
            FD_SET (sd, &readfds);
            select (sd + 1, &readfds, NULL, NULL, &tv);

            /* make sure some data has arrived */
            if (!FD_ISSET (sd, &readfds)) {     /* it hasn't */
                  if (!recv_length) {
                        strcpy (recv_buffer, "");
                        printf ("%s\n", _("No data was received from host!"));
                        result = STATE_WARNING;
                  }
                  else {                                                            /* this one failed, but previous ones worked */
                        recv_buffer[recv_length] = 0;
                  }
                  break;
            }
            else {                                                                  /* it has */
                  recv_result =
                        recv (sd, recv_buffer + recv_length, 
                              (size_t)recv_size - recv_length - 1, 0);
                  if (recv_result == -1) {
                        /* recv failed, bail out */
                        strcpy (recv_buffer + recv_length, "");
                        result = STATE_WARNING;
                        break;
                  }
                  else if (recv_result == 0) {
                        /* end of file ? */
                        recv_buffer[recv_length] = 0;
                        break;
                  }
                  else {                                                            /* we got data! */
                        recv_length += recv_result;
                        if (recv_length >= recv_size - 1) {
                              /* buffer full, we're done */
                              recv_buffer[recv_size - 1] = 0;
                              break;
                        }
                  }
            }
            /* end if(!FD_ISSET(sd,&readfds)) */
      }
      /* end while(1) */

      close (sd);
      return result;
}


/* connects to a host on a specified port, sends a string, and gets a 
   response */
int
process_request (const char *server_address, int server_port, int proto,
      const char *send_buffer, char *recv_buffer, int recv_size)
{
      int result;
      int sd;

      result = STATE_OK;

      result = np_net_connect (server_address, server_port, &sd, proto);
      if (result != STATE_OK)
            return STATE_CRITICAL;

      result = send_request (sd, proto, send_buffer, recv_buffer, recv_size);

      close (sd);

      return result;
}


/* opens a tcp or udp connection to a remote host or local socket */
int
np_net_connect (const char *host_name, int port, int *sd, int proto)
{
      struct addrinfo hints;
      struct addrinfo *r, *res;
      struct sockaddr_un su;
      char port_str[6], host[MAX_HOST_ADDRESS_LENGTH];
      size_t len;
      int socktype, result;

      socktype = (proto == IPPROTO_UDP) ? SOCK_DGRAM : SOCK_STREAM;

      /* as long as it doesn't start with a '/', it's assumed a host or ip */
      if(host_name[0] != '/'){
            memset (&hints, 0, sizeof (hints));
            hints.ai_family = address_family;
            hints.ai_protocol = proto;
            hints.ai_socktype = socktype;

            len = strlen (host_name);
            /* check for an [IPv6] address (and strip the brackets) */
            if (len >= 2 && host_name[0] == '[' && host_name[len - 1] == ']') {
                  host_name++;
                  len -= 2;
            }
            if (len >= sizeof(host))
                  return STATE_UNKNOWN;
            memcpy (host, host_name, len);
            host[len] = '\0';
            snprintf (port_str, sizeof (port_str), "%d", port);
            result = getaddrinfo (host, port_str, &hints, &res);

            if (result != 0) {
                  printf ("%s\n", gai_strerror (result));
                  return STATE_UNKNOWN;
            }

            r = res;
            while (r) {
                  /* attempt to create a socket */
                  *sd = socket (r->ai_family, socktype, r->ai_protocol);

                  if (*sd < 0) {
                        printf ("%s\n", _("Socket creation failed"));
                        freeaddrinfo (r);
                        return STATE_UNKNOWN;
                  }

                  /* attempt to open a connection */
                  result = connect (*sd, r->ai_addr, r->ai_addrlen);

                  if (result == 0) {
                        was_refused = FALSE;
                        break;
                  }

                  if (result < 0) {
                        switch (errno) {
                        case ECONNREFUSED:
                              was_refused = TRUE;
                              break;
                        }
                  }

                  close (*sd);
                  r = r->ai_next;
            }
            freeaddrinfo (res);
      } 
      /* else the hostname is interpreted as a path to a unix socket */
      else {
            if(strlen(host_name) >= UNIX_PATH_MAX){
                  die(STATE_UNKNOWN, _("Supplied path too long unix domain socket"));
            }
            memset(&su, 0, sizeof(su));
            su.sun_family = AF_UNIX;
            strncpy(su.sun_path, host_name, UNIX_PATH_MAX);
            *sd = socket(PF_UNIX, SOCK_STREAM, 0);
            if(*sd < 0){
                  die(STATE_UNKNOWN, _("Socket creation failed"));
            }
            result = connect(*sd, (struct sockaddr *)&su, sizeof(su));
            if (result < 0 && errno == ECONNREFUSED)
                  was_refused = TRUE;
      }

      if (result == 0)
            return STATE_OK;
      else if (was_refused) {
            switch (econn_refuse_state) { /* a user-defined expected outcome */
            case STATE_OK:       
            case STATE_WARNING:  /* user wants WARN or OK on refusal */
                  return econn_refuse_state;
                  break;
            case STATE_CRITICAL: /* user did not set econn_refuse_state */
                  printf ("%s\n", strerror(errno));
                  return econn_refuse_state;
                  break;
            default: /* it's a logic error if we do not end up in STATE_(OK|WARNING|CRITICAL) */
                  return STATE_UNKNOWN;
                  break;
            }
      }
      else {
            printf ("%s\n", strerror(errno));
            return STATE_CRITICAL;
      }
}

int
send_request (int sd, int proto, const char *send_buffer, char *recv_buffer, int recv_size)
{
      int result = STATE_OK;
      int send_result;
      int recv_result;
      struct timeval tv;
      fd_set readfds;

      send_result = send (sd, send_buffer, strlen (send_buffer), 0);
      if (send_result<0 || (size_t)send_result!=strlen(send_buffer)) {
            printf ("%s\n", _("Send failed"));
            result = STATE_WARNING;
      }

      /* wait up to the number of seconds for socket timeout minus one 
         for data from the host */
      tv.tv_sec = socket_timeout - 1;
      tv.tv_usec = 0;
      FD_ZERO (&readfds);
      FD_SET (sd, &readfds);
      select (sd + 1, &readfds, NULL, NULL, &tv);

      /* make sure some data has arrived */
      if (!FD_ISSET (sd, &readfds)) {
            strcpy (recv_buffer, "");
            printf ("%s\n", _("No data was received from host!"));
            result = STATE_WARNING;
      }

      else {
            recv_result = recv (sd, recv_buffer, (size_t)recv_size - 1, 0);
            if (recv_result == -1) {
                  strcpy (recv_buffer, "");
                  if (proto != IPPROTO_TCP)
                        printf ("%s\n", _("Receive failed"));
                  result = STATE_WARNING;
            }
            else
                  recv_buffer[recv_result] = 0;

            /* die returned string */
            recv_buffer[recv_size - 1] = 0;
      }
      return result;
}


int
is_host (const char *address)
{
      if (is_addr (address) || is_hostname (address))
            return (TRUE);

      return (FALSE);
}

void
host_or_die(const char *str)
{
      if(!str || (!is_addr(str) && !is_hostname(str)))
            usage_va(_("Invalid hostname/address - %s"), str);
}

int
is_addr (const char *address)
{
#ifdef USE_IPV6
      if (address_family == AF_INET && is_inet_addr (address))
            return TRUE;
      else if (address_family == AF_INET6 && is_inet6_addr (address)) 
            return TRUE;
#else
      if (is_inet_addr (address))
            return (TRUE);
#endif

      return (FALSE);
}

int
resolve_host_or_addr (const char *address, int family)
{
      struct addrinfo hints;
      struct addrinfo *res;
      int retval;

      memset (&hints, 0, sizeof (hints));
      hints.ai_family = family;
      retval = getaddrinfo (address, NULL, &hints, &res);

      if (retval != 0)
            return FALSE;
      else {
            freeaddrinfo (res);
            return TRUE;
      }
}

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