X-Git-Url: http://git.subgeniuskitty.com/icmpmonitor/.git/blobdiff_plain/b50b99d422783b77e867f5486e5703b780efbc1c..22e9f47e32f5905d2bd9ae5ee35020ace9091428:/icmpmonitor.c diff --git a/icmpmonitor.c b/icmpmonitor.c index 870a4e2..462c920 100644 --- a/icmpmonitor.c +++ b/icmpmonitor.c @@ -1,767 +1,461 @@ /* - * Copyright (c) 1989 The Regents of the University of California. - * All rights reserved. + * ICMPmonitor * - * This code is derived from software contributed to Berkeley by - * Mike Muuss. + * Monitors hosts using ICMP 'echo', executing a user-specified command + * whenever hosts change state between responsive and unresponsive. * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions - * are met: - * 1. Redistributions of source code must retain the above copyright - * notice, this list of conditions and the following disclaimer. - * 2. Redistributions in binary form must reproduce the above copyright - * notice, this list of conditions and the following disclaimer in the - * documentation and/or other materials provided with the distribution. - * 3. All advertising materials mentioning features or use of this software - * must display the following acknowledgement: - * This product includes software developed by the University of - * California, Berkeley and its contributors. - * 4. Neither the name of the University nor the names of its contributors - * may be used to endorse or promote products derived from this software - * without specific prior written permission. + * © 2019 Aaron Taylor + * © 1999 Vadim Zaliva + * © 1989 The Regents of the University of California & Mike Muuss * - * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND - * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE - * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE - * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE - * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL - * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS - * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) - * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT - * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY - * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF - * SUCH DAMAGE. + * See LICENSE file for copyright and license details. */ -/* - * ICMPMONITOR.C - * - * Using the InterNet Control Message Protocol (ICMP) "ECHO" facility, - * monitor several hosts, and notify admin if some of them are down. - * - * Author - - * Vadim Zaliva - * - * Status - - * Public Domain. Distribution Unlimited. - */ - -char copyright[] = -"@(#) Copyright (c) 1989 The Regents of the University of California.\n" -"All rights reserved.\n"; +/* Wishlist */ +/* TODO: Add IPv6 support. */ +/* TODO: Turn the global '-r' functionality into per-host config file option. */ +/* TODO: Add 'auto' keyword to 'start_condition', testing host on startup. */ +/* TODO: Double-check the network code when interrupted while receiving a packet. */ -char rcsid[] = "$Id: icmpmonitor.c,v 1.8 2004/05/28 01:33:07 lord Exp $"; - -#include #include #include -#ifdef HAVE_SYSLOG_H -# include -#endif -#include +#include #include #include -#ifdef HAVE_SYS_TIME_H -# include -# include -#endif +#include +#include #include #include -#ifdef HAVE_FCNTL_H -# include -#endif -#ifdef HAVE_SYS_FCNTL_H -# include -#endif -#ifdef HAVE_UNISTD_H -# include -#endif - -#include - +#include #include #include #include -#include #include #include - -/* Workaround for broken ICMP header on Slackware 4.x */ -#ifdef _LINUX_ICMP_H -# warning "Broken Slackware 4.x 'netinet/ip_icmp.h' header detected. Using replacement 'struct icmp' definition." -# define ICMP_MINLEN 8 -struct icmp -{ - u_int8_t icmp_type; - u_int8_t icmp_code; - u_int16_t icmp_cksum; - union - { - struct ih_idseq - { - u_int16_t icd_id; - u_int16_t icd_seq; - } ih_idseq; - } icmp_hun; - -# define icmp_id icmp_hun.ih_idseq.icd_id -# define icmp_seq icmp_hun.ih_idseq.icd_seq - - union { - u_int8_t id_data[1]; - } icmp_dun; - -# define icmp_data icmp_dun.id_data - -}; -#endif /* _LINUX_ICMP_H */ - -#include #include +#include -#include "cfg.h" +#include "iniparser/iniparser.h" -/* defines */ +#define VERSION 2 -/* #define DEBUG */ +#define MAXPACKETSIZE (65536 - 60 - 8) /* TODO: What are the magic numbers? */ +#define DEFAULTDATALEN (64 - 8) /* TODO: What are the magic numbers? */ -#ifndef nil -# define nil NULL -#endif +/* ICMP header contains: type, code, checksum, identifier and sequence number. */ +#define ICMP_ECHO_HEADER_BYTES 8 +#define ICMP_ECHO_DATA_BYTES sizeof(struct timeval) +#define ICMP_ECHO_PACKET_BYTES ICMP_ECHO_HEADER_BYTES + ICMP_ECHO_DATA_BYTES -/* return codes */ -#define RET_OK 0 -#define RET_NO_HOSTS 1 -#define RET_INIT_ERROR 2 -#define RET_BAD_CFG 3 -#define RET_BAD_OPT 4 +/* Minimum time in seconds between pings. If this value is increased above the */ +/* `ping_interval` for a given host, some pings to that host may not be sent. */ +#define TIMER_RESOLUTION 1 -#define MAXPACKET (65536 - 60 - 8) /* max packet size */ -#define DEFDATALEN (64 - 8) /* default data length */ +/* Must be larger than the length of the longest configuration key (currently 'start_condition'). */ +#define MAXCONFKEYLEN 20 -#define VERSION "ICMPmonitor v1.2 by lord@crocodile.org" -#define MAX_LOG_MSG_SIZE 4096 - -# define icmphdr icmp - -/* typedefs */ -typedef struct monitor_host -{ - /* following are coming from cfg */ - char *name; +/* One struct per host as listed in the config file. */ +struct host_entry { + /* From the config file */ + char * name; int ping_interval; int max_delay; - char *upcmd; - char *downcmd; - - /* following values are calculated */ - int socket; - struct timeval last_ping_received; - struct timeval last_ping_sent; - int up; - int down; + char * up_cmd; + char * down_cmd; + + /* Calculated values */ + int socket; + struct timeval last_ping_received; + struct timeval last_ping_sent; + bool host_up; struct sockaddr_in dest; - unsigned int sentpackets ; - unsigned int recvdpackets; - - /* linked list */ - struct monitor_host *next; -} monitor_host_t; - -/* protos */ -static void logopen(void); -static void logclose(void); -static void log(int type, char *format, ...); -static int gethostaddr(const char *name); -static void read_hosts(const char *cfg_file_name); -static void init_hosts(void); -static void get_response(void); -static void pinger(int); -static int in_cksum(u_short *addr, int len); -static void read_icmp_data(monitor_host_t *p); -static void tvsub(struct timeval *out, struct timeval *in); -static void done(int code); -static void start_daemon(void); -static int gcd(int x, int y); - -/* globals */ - -static monitor_host_t **hosts = nil; -static int isDaemon = 0; -static int isVerbose = 0; -static int keepBanging = 0; -static unsigned short ident; -static int send_delay = 1; - -int main(int ac, char **av) -{ - extern char* optarg; - extern int optind; - char *cfgfile=nil; - int param; - - logopen(); - log(LOG_INFO, VERSION " is starting."); - - while((param = getopt(ac, av, "rvdf:")) != -1) - switch(param) - { - case 'v': - isVerbose = 1; - break; - case 'd': - isDaemon = 1; - break; - case 'r': - keepBanging = 1; - break; - case 'f': - cfgfile=strdup(optarg); - break; - default: - fprintf(stderr,"Usage: icmpmonitor [-d] [-v] [-r] [-f cfgfile]\n"); - done(RET_BAD_OPT); - } - - if(!cfgfile) - { - log(LOG_WARNING,"No cfg file specified. Assuming 'icmpmonitor.cfg'"); - cfgfile="icmpmonitor.cfg"; - } - - read_hosts(cfgfile); /* we do this before becoming daemon, - to be able process relative path */ - - if(isDaemon) - start_daemon(); - - init_hosts(); - - ident=getpid() & 0xFFFF; - - (void)signal(SIGALRM, pinger); - alarm(send_delay); - - get_response(); - - done(RET_OK); -} + /* Linked list */ + struct host_entry * next; +}; +/* Globals */ + /* Since the program is based around signals, a linked list of hosts is maintained here. */ + static struct host_entry * first_host_in_list = NULL; + /* Set by command line flags. */ + static bool verbose = false; + static bool retry_down_cmd = false; /* - * in_cksum -- - * Checksum routine for Internet Protocol family headers (C Version) + * Generate an Internet Checksum per RFC 1071. + * + * This is not a general purpose implementation of RFC 1071. Since we only + * send ICMP echo packets, we assume 'data' will contain a specific number of + * bytes. */ -static int -in_cksum(u_short *addr, int len) +uint16_t +checksum(const uint16_t * data) { - register int nleft = len; - register u_short *w = addr; - register int sum = 0; - u_short answer = 0; - - /* - * Our algorithm is simple, using a 32 bit accumulator (sum), we add - * sequential 16 bit words to it, and at the end, fold back all the - * carry bits from the top 16 bits into the lower 16 bits. - */ - while (nleft > 1) { - sum += *w++; - nleft -= 2; - } - - /* mop up an odd byte, if necessary */ - if (nleft == 1) { - *(u_char *)(&answer) = *(u_char *)w ; - sum += answer; + uint32_t accumulator = 0; + for (size_t i = 0; i < ICMP_ECHO_PACKET_BYTES / 2; i++) { + accumulator += ntohs(data[i]); + if (accumulator > 0xffff) accumulator -= 0xffff; } - - /* add back carry outs from top 16 bits to low 16 bits */ - sum = (sum >> 16) + (sum & 0xffff); /* add hi 16 to low 16 */ - sum += (sum >> 16); /* add carry */ - answer = ~sum; /* truncate to 16 bits */ - return(answer); + return htons(~accumulator); } /* - * pinger -- - * Compose and transmit an ICMP ECHO REQUEST packet. The IP packet - * will be added on by the kernel. The ID field is our UNIX process ID, - * and the sequence number is an ascending integer. The first 8 bytes - * of the data portion are used to hold a UNIX "timeval" struct in VAX - * byte-order, to compute the round-trip time. + * Calculate difference (a-b) between two timeval structs. */ -static void pinger(int ignore) +void +timeval_diff(struct timeval * a, const struct timeval * b) { - register struct icmphdr *icp; - register int cc; - int i; - monitor_host_t *p; - u_char outpack[MAXPACKET]; - - p=hosts[0]; - while(p) - { - if(p->socket!=-1) - { - struct timeval now; - - (void)gettimeofday(&now,(struct timezone *)NULL); - tvsub(&now, &p->last_ping_received); - - if(now.tv_sec > (p->max_delay+p->ping_interval)) - { - p->up=0; - if((!p->down) || keepBanging) - { - p->down = 1; - - if(isVerbose) - log(LOG_INFO,"Host %s in down. Executing DOWN command",p->name); - if(!fork()) - { - system(p->downcmd); - exit(0); - } else - { - wait(nil); - } - } - } - - (void)gettimeofday(&now,(struct timezone *)NULL); - tvsub(&now, &p->last_ping_sent); - - if(now.tv_sec > p->ping_interval) - { - /* Time to send ping */ - - icp = (struct icmphdr *)outpack; - icp->icmp_type = ICMP_ECHO; - icp->icmp_code = 0; - icp->icmp_cksum = 0; - icp->icmp_seq = p->socket; - icp->icmp_id = ident; - - if(isVerbose) - log(LOG_INFO,"Sending ICMP packet to %s.",p->name); - - (void)gettimeofday((struct timeval *)&outpack[8], - (struct timezone *)NULL); - - cc = DEFDATALEN + 8; /* skips ICMP portion */ - - /* compute ICMP checksum here */ - icp->icmp_cksum = in_cksum((u_short *)icp, cc); - - i = sendto(p->socket, (char *)outpack, cc, 0, (const struct sockaddr *)(&p->dest), - sizeof(struct sockaddr)); - - (void)gettimeofday(&p->last_ping_sent, - (struct timezone *)NULL); - - if(i<0 || i!=cc) - { - if(i<0) - log(LOG_WARNING,"Sending ICMP packet to %s failed.",p->name); - } - p->sentpackets++; - } - } - p=p->next; - + if (a->tv_usec < b->tv_usec) { + a->tv_sec--; + a->tv_usec += 1000000; } - - (void)signal(SIGALRM, pinger); /* restore handler */ - alarm(send_delay); + a->tv_usec -= b->tv_usec; + a->tv_sec -= b->tv_sec; } -static void get_response(void) +/* + * This function iterates over the list of hosts, pinging any which are due. + */ +void +pinger(int ignore) /* Dummy parameter since this function registers as a signal handler. */ { - fd_set rfds; - int retval; - monitor_host_t *p; - int maxd=-1; - - while(1) - { - p=hosts[0]; - FD_ZERO(&rfds); - while(p) - { - if(p->socket != -1) - { - if(p->socket > maxd) - maxd=p->socket; - FD_SET(p->socket, &rfds); + assert(first_host_in_list); + + struct icmp * icmp_packet; + struct host_entry * host = first_host_in_list; + unsigned char packet[IP_PACKET_MAX_BYTES]; /* Use char so this can be aliased later. */ + + while (host) { + struct timeval elapsed_time; + gettimeofday(&elapsed_time, NULL); + timeval_diff(&elapsed_time, &host->last_ping_received); + + if ((elapsed_time.tv_sec > host->max_delay) && (host->host_up || retry_down_cmd)) { + if (verbose) printf("INFO: Host %s stopped responding. Executing DOWN command.\n", host->name); + host->host_up = false; + if (!fork()) { + system(host->down_cmd); + exit(EXIT_SUCCESS); } - p=p->next; } - retval = select(maxd+1, &rfds, nil, nil, nil); - if(retval<0) - { - /* we get her in case we are interrupted by signal. - it's ok. */ - } - else - { - if(retval>0) - { - /* log(LOG_DEBUG,"ICMP data is available now."); */ - p=hosts[0]; - while(p) - { - if(p->socket!=-1 && FD_ISSET(p->socket, &rfds)) - { - /* Read data */ - read_icmp_data(p); - } - p=p->next; - } - } else - { - log(LOG_DEBUG,"select returns 0."); /* TODO */ + if (elapsed_time.tv_sec > host->ping_interval) { + if (verbose) printf("INFO: Sending ICMP packet to %s.\n", host->name); + + icmp_packet = (struct icmp *) packet; + icmp_packet->icmp_type = ICMP_ECHO; + icmp_packet->icmp_code = 0; + icmp_packet->icmp_cksum = 0; + icmp_packet->icmp_seq = host->socket; + icmp_packet->icmp_id = getpid() & 0xFFFF; + + /* Write a timestamp struct in the packet's data segment for use in calculating travel times. */ + gettimeofday((struct timeval *) &packet[ICMP_ECHO_HEADER_BYTES], NULL); + + icmp_packet->icmp_cksum = checksum((uint16_t *) packet); + + size_t bytes_sent = sendto(host->socket, packet, ICMP_ECHO_PACKET_BYTES, 0, + (const struct sockaddr *) &host->dest, + sizeof(struct sockaddr)); + + if (bytes_sent == ICMP_ECHO_PACKET_BYTES) { + gettimeofday(&host->last_ping_sent, NULL); + } else { + fprintf(stderr, "WARN: Failed sending ICMP packet to %s.\n", host->name); } } + host = host->next; } + + signal(SIGALRM, pinger); + alarm(TIMER_RESOLUTION); } -static void read_icmp_data(monitor_host_t *p) +void +read_icmp_data(struct host_entry * host) { - socklen_t fromlen ; - struct sockaddr_in from ; - int cc ; - struct ip *ip ; - struct icmp *icmp ; - int iphdrlen ; - int delay ; - struct timeval tv ; - unsigned char buf[MAXPACKET]; /* read buffer */ - - (void)gettimeofday(&tv, (struct timezone *)NULL); - - fromlen = sizeof(from); - if((cc = recvfrom(p->socket, buf, sizeof(buf), 0, - (struct sockaddr *)&from, &fromlen)) < 0) - { - if(errno != EINTR) - log(LOG_WARNING,"Error reading ICMP data from %s.",p->name); + struct timeval now; + gettimeofday(&now, NULL); + + struct sockaddr_in from; + socklen_t fromlen = sizeof(from); + int bytes; + unsigned char packet[IP_PACKET_MAX_BYTES]; /* Use char so this can be aliased later. */ + if ((bytes = recvfrom(host->socket, packet, sizeof(packet), 0, (struct sockaddr *) &from, &fromlen)) < 0) { + if (errno != EINTR) fprintf(stderr, "WARN: Error reading ICMP data from %s.\n", host->name); return; - } - - /* log(LOG_DEBUG,"Got %d bytes of ICMP data from %s.",cc, p->name); */ - - /* check IP header actual len */ - ip = (struct ip *)buf ; - iphdrlen = ip->ip_hl<<2 ; - icmp = (struct icmp *) (buf+iphdrlen) ; - - if(cc < iphdrlen+ICMP_MINLEN) - { - log(LOG_WARNING,"Received short packet from %s.",p->name); + } + + struct ip * ip = (struct ip *) packet; + int iphdrlen = ip->ip_hl << 2; + struct icmp * icmp = (struct icmp *) (packet + iphdrlen); + + if (bytes < iphdrlen + ICMP_MINLEN) { + fprintf(stderr, "WARN: Received short packet from %s.\n", host->name); return; } - - if(icmp->icmp_type == ICMP_ECHOREPLY && - icmp->icmp_id == ident && - icmp->icmp_seq == p->socket) - { - p->recvdpackets++; - - memcpy(&p->last_ping_received, &tv, sizeof(tv)); - - tvsub(&tv, (struct timeval *) &icmp->icmp_data[0]); - delay=tv.tv_sec*1000+(tv.tv_usec/1000); - - if(isVerbose) - log(LOG_INFO,"Got ICMP reply from %s in %d ms.",p->name,delay); - p->down=0; - if(!p->up) - { - p->up=1; - if(isVerbose) - log(LOG_INFO,"Host %s in now up. Executing UP command",p->name); - if(!fork()) - { - system(p->upcmd); - exit(0); - } else - { - wait(nil); + + if (icmp->icmp_type == ICMP_ECHOREPLY && icmp->icmp_id == (getpid() & 0xFFFF) && icmp->icmp_seq == host->socket) { + memcpy(&host->last_ping_received, &now, sizeof(now)); + if (verbose) printf("INFO: Got ICMP reply from %s.\n", host->name); + if (!host->host_up) { + if (verbose) printf("INFO: Host %s started responding. Executing UP command.\n", host->name); + host->host_up = true; + if (!fork()) { + system(host->up_cmd); + exit(EXIT_SUCCESS); } } - } else - { - /* - log(LOG_DEBUG,"ICMP packet of type %d from %s. Ident=%d",icmp->icmp_type, - p->name, - icmp->icmp_id - ); - */ + } else { + /* The packet isn't what we expected. Ignore it and move on. */ } } -static void read_hosts(const char *cfg_file_name) +/* + * This function contains the main program loop, listening for replies to pings + * sent from the signal-driven pinger(). + */ +void +get_response(void) { - int i,n=0; - struct Cfg *cfg; - - if((cfg=readcfg(cfg_file_name))==NULL) - { - log(LOG_ERR,"Error reading cfg. Exiting."); - done(RET_BAD_CFG); - } - - if(cfg->nelements) - { - hosts=malloc(sizeof(monitor_host_t *)*cfg->nelements); - for(i=0;inelements;i++) - { - if(cfg->dict[i]->nvalues<4) - { - log(LOG_ERR,"Not enough fields in record %d of cfg file. Got %d.",n, cfg->dict[i]->nvalues+1); - done(RET_BAD_CFG); - } else if(cfg->dict[i]->nvalues>5) - { - log(LOG_ERR,"Too many fields in record %d of cfg file. Got %d.",n, cfg->dict[i]->nvalues+1); - done(RET_BAD_CFG); - } - - hosts[n]=malloc(sizeof(monitor_host_t)); - hosts[n]->name = strdup(cfg->dict[i]->name); - hosts[n]->ping_interval = atoi (cfg->dict[i]->value[0]); - hosts[n]->max_delay = atoi (cfg->dict[i]->value[1]); - hosts[n]->upcmd = strdup(cfg->dict[i]->value[2]); - hosts[n]->downcmd = strdup(cfg->dict[i]->value[3]); - - if(cfg->dict[i]->nvalues==4) - { - hosts[n]->down = 0; - hosts[n]->up = 1; - } else if(strcmp(cfg->dict[i]->value[4], "up")==0) - { - hosts[n]->down = 0; - hosts[n]->up = 1; - } else if(strcmp(cfg->dict[i]->value[4], "down")==0) - { - hosts[n]->down = 1; - hosts[n]->up = 0; - } else if(strcmp(cfg->dict[i]->value[4], "auto")==0) - { - hosts[n]->down = 1; - hosts[n]->up = 1; - } else if(strcmp(cfg->dict[i]->value[4], "none")==0) - { - hosts[n]->down = 0; - hosts[n]->up = 0; - } else - { - log(LOG_ERR,"Illegal value %s in record %n for startup condition.", cfg->dict[i]->value[4], n); - done(RET_BAD_CFG); - } - hosts[n]->sentpackets = 0; - hosts[n]->recvdpackets = 0; - - hosts[n]->socket = -1; - hosts[n]->next = nil; - if(n>0) - hosts[n-1]->next=hosts[n]; - (void)gettimeofday(&(hosts[n]->last_ping_received), (struct timezone *)NULL); - - n++; - } - } + while (true) { + fd_set rfds; + FD_ZERO(&rfds); + + assert(first_host_in_list); + struct host_entry * host = first_host_in_list; - freecfg(cfg); + int max_fd = -1; + while (host) { + if (host->socket > max_fd) max_fd = host->socket; + FD_SET(host->socket, &rfds); + host = host->next; + } - if(n<=0) - { - log(LOG_ERR,"No hosts defined in cfg file, exiting."); - done(RET_NO_HOSTS); + int retval; + if ((retval = select(max_fd+1, &rfds, NULL, NULL, NULL)) > 0) { + assert(first_host_in_list); + host = first_host_in_list; + while (host) { + if (FD_ISSET(host->socket, &rfds)) read_icmp_data(host); + host = host->next; + } + } else { + /* An error or interruption occurred. */ + /* We can't do anything about it, so loop and try again. */ + } } - else - log(LOG_DEBUG,"%d host(s) found in cfg file,", n); - } -static int gethostaddr(const char *name) +/* + * Parse a configuration file using the `iniparser` library. + * See `icmpmonitor.ini` and `README.md` for examples and reference. + */ +void +parse_config(const char * conf_file) { - static int res; - struct hostent *he; - - if((res=inet_addr(name))<0) - { - he=gethostbyname(name); - if(!he) - return -1; - memcpy( &res , he->h_addr , he->h_length ); - } - return(res); -} + dictionary * conf = iniparser_load(conf_file); + if (conf == NULL) { + fprintf(stderr, "ERROR: Unable to parse configuration file %s.\n", conf_file); + exit(EXIT_FAILURE); + } -static void init_hosts(void) -{ - monitor_host_t *p=hosts[0]; - struct protoent *proto; - int ok=0; - - if((proto=getprotobyname("icmp"))==nil) - { - log(LOG_ERR,"Unknown protocol: icmp. Exiting."); - done(RET_INIT_ERROR); + int host_count = iniparser_getnsec(conf); + if (host_count < 1 ) { + fprintf(stderr, "ERROR: Unable to determine number of hosts in configuration file.\n"); + exit(EXIT_FAILURE); } - - while(p) - { - log(LOG_DEBUG,"resolving host %s", p->name); - - bzero(&p->dest,sizeof(p->dest)); - p->dest.sin_family=AF_INET; - if((p->dest.sin_addr.s_addr=gethostaddr(p->name))<=0) - { - log(LOG_ERR,"Can't resolve host. Skipping client %s.",p->name); - p->socket=-1; - } else - { - if((p->socket=socket(AF_INET,SOCK_RAW,proto->p_proto))<0) - { - log(LOG_ERR,"Can't create socket. Skipping client %s.",p->name); - p->socket=-1; - } else - { - if(ok==0) - send_delay = p->ping_interval; - else - send_delay = gcd(send_delay, p->ping_interval); - ok++; - } + + struct host_entry * host_list_end = NULL; + for (int i=0; i < host_count; i++) { + /* Allocate a reusable buffer large enough to hold the full 'section:key' string. */ + int section_len = strlen(iniparser_getsecname(conf, i)); + char * key_buf = malloc(section_len + 1 + MAX_CONF_KEY_LEN + 1); /* +1 for ':' and '\0' */ + strcpy(key_buf, iniparser_getsecname(conf, i)); + key_buf[section_len++] = ':'; + + struct host_entry * cur_host = malloc(sizeof(struct host_entry)); + + key_buf[section_len] = '\0'; + strncat(key_buf, "host", MAX_CONF_KEY_LEN); + cur_host->name = strdup(iniparser_getstring(conf, key_buf, NULL)); + + key_buf[section_len] = '\0'; + strncat(key_buf, "interval", MAX_CONF_KEY_LEN); + cur_host->ping_interval = iniparser_getint(conf, key_buf, -1); + + key_buf[section_len] = '\0'; + strncat(key_buf, "max_delay", MAX_CONF_KEY_LEN); + cur_host->max_delay = iniparser_getint(conf, key_buf, -1); + + key_buf[section_len] = '\0'; + strncat(key_buf, "up_cmd", MAX_CONF_KEY_LEN); + cur_host->up_cmd = strdup(iniparser_getstring(conf, key_buf, NULL)); + + key_buf[section_len] = '\0'; + strncat(key_buf, "down_cmd", MAX_CONF_KEY_LEN); + cur_host->down_cmd = strdup(iniparser_getstring(conf, key_buf, NULL)); + + key_buf[section_len] = '\0'; + strncat(key_buf, "start_condition", MAX_CONF_KEY_LEN); + const char * value = iniparser_getstring(conf, key_buf, NULL); + if (value) cur_host->host_up = *value == 'u' ? true : false; + + if (cur_host->name == NULL || cur_host->ping_interval == -1 || cur_host->max_delay == -1) { + fprintf(stderr, "ERROR: Problems parsing section %s.\n", iniparser_getsecname(conf, i)); + exit(EXIT_FAILURE); + } + + cur_host->socket = -1; + cur_host->next = NULL; + gettimeofday(&(cur_host->last_ping_received), (struct timezone *) NULL); + + if (first_host_in_list == NULL) { + first_host_in_list = cur_host; + host_list_end = cur_host; + } else { + host_list_end->next = cur_host; + host_list_end = cur_host; } - p=p->next; - } - if(!ok) - { - log(LOG_ERR,"No hosts left to process, exiting."); - done(RET_NO_HOSTS); + free(key_buf); } + iniparser_freedict(conf); } /* - * tvsub -- - * Subtract 2 timeval structs: out = out - in. Out is assumed to - * be >= in. + * Parse string (IP or hostname) to Internet address. + * + * Returns 0 if host can't be resolved, otherwise returns an Internet address. */ -static void -tvsub(register struct timeval *out, register struct timeval *in) +uint32_t +get_host_addr(const char * name) { - if ((out->tv_usec -= in->tv_usec) < 0) { - --out->tv_sec; - out->tv_usec += 1000000; - } - out->tv_sec -= in->tv_sec; + struct addrinfo hints; + memset(&hints, 0, sizeof(hints)); + hints.ai_family = AF_INET; + + int rv; + struct addrinfo * address; + if ((rv = getaddrinfo(name, NULL, &hints, &address)) != 0) return 0; + uint32_t result = ((struct sockaddr_in *)(address->ai_addr))->sin_addr.s_addr; + freeaddrinfo(address); + return result; } -void done(int code) +size_t +gcd(const size_t x, const size_t y) { - logclose(); - exit(code); + size_t remainder = x % y; + if (remainder == 0) return y; + return gcd(y, remainder); } -void start_daemon(void) +void +remove_host_from_list(struct host_entry * host) { - if(fork()) - exit(0); - - chdir("/"); - umask(0); - (void) close(0); - (void) close(1); - (void) close(2); - (void) open("/", O_RDONLY); - (void) dup2(0, 1); - (void) dup2(0, 2); - setsid(); + assert(first_host_in_list); + assert(host); + + if (host == first_host_in_list) { + first_host_in_list = host->next; + } else { + struct host_entry * temp = first_host_in_list; + while (temp->next != host && temp->next != NULL) temp = temp->next; + if (temp->next == NULL) return; + temp->next = temp->next->next; + } + free(host); } -static void logopen(void) +void +init_hosts(void) { -#if HAVE_OPENLOG - if(isDaemon) - openlog("icmpmonitor", LOG_PID| LOG_CONS|LOG_NOWAIT, LOG_USER); -#else - log(LOG_WARNING,"Compiled without syslog. Syslog can't be used."); -#endif + struct host_entry * host; + struct protoent * proto; + + if ((proto = getprotobyname("icmp")) == NULL) { + fprintf(stderr, "ERROR: Unknown protocol: icmp.\n"); + exit(EXIT_FAILURE); + } + + assert(first_host_in_list); + host = first_host_in_list; + while (host) { + struct host_entry * next_host = host->next; + bzero(&host->dest, sizeof(host->dest)); + host->dest.sin_family = AF_INET; + if (!(host->dest.sin_addr.s_addr = get_host_addr(host->name))) { + fprintf(stderr, "WARN: Removing unresolvable host %s from list.\n", host->name); + remove_host_from_list(host); + } + host = next_host; + } + + assert(first_host_in_list); + host = first_host_in_list; + while (host) { + struct host_entry * next_host = host->next; + if ((host->socket = socket(AF_INET, SOCK_RAW, proto->p_proto)) < 0) { + fprintf(stderr, "WARN: Failed creating socket. Removing host %s from list.\n", host->name); + remove_host_from_list(host); + } + host = next_host; + } } -static void logclose(void) +void +print_usage(char ** argv) { -#if HAVE_CLOSELOG - if(isDaemon) - closelog(); -#endif + printf( "ICMPmonitor v%d (www.subgeniuskitty.com)\n" + "Usage: %s [-h] [-v] [-r] -f \n" + " -v Verbose mode. Prints message for each packet sent and received.\n" + " -r Repeat down_cmd every time a host fails to respond to a packet.\n" + " Note: Default behavior executes down_cmd only once, resetting once the host is back up.\n" + " -h Help (prints this message)\n" + " -f Specify a configuration file.\n" + , VERSION, argv[0]); } -/** - * This function should be used as central logging facility. - * 'type' argument should be one of following: - * - * LOG_EMERG system is unusable - * LOG_ALERT action must be taken immediately - * LOG_CRIT critical conditions - * LOG_ERR error conditions - * LOG_WARNING warning conditions - * LOG_NOTICE normal but significant condition - * LOG_INFO informational - * LOG_DEBUG debug-level messages - */ -static void log(int type, char *format, ...) +void +parse_params(int argc, char ** argv) { - va_list ap; - -#ifndef DEBUG - if(type==LOG_DEBUG) - return; -#endif - - va_start(ap, format); - - if(isDaemon) - { - char buffer[MAX_LOG_MSG_SIZE]; - -#if HAVE_VSNPRINTF - (void)vsnprintf(buffer, MAX_LOG_MSG_SIZE, format, ap); -#else -# if HAVE_VSPRINTF -# warning "Using VSPRINTF. Buffer overflow could happen!" - (void)vsprintf(buffer, format, ap); -# else -# error "Your standard libabry have neither vsnprintf nor vsprintf defined. One of them is reqired!" -# endif -#endif -#if HAVE_SYSLOG - syslog(type,buffer); -#endif - } else - { - (void) fprintf(stderr, "icmpmonitor[%d]:", (int)getpid()); - (void) vfprintf(stderr, format, ap); - (void) fprintf(stderr, "\n"); + int param; + while ((param = getopt(argc, argv, "hrvf:")) != -1) { + switch(param) { + case 'v': + verbose = true; + break; + case 'r': + retry_down_cmd = true; + break; + case 'f': + parse_config(optarg); + break; + case 'h': + default: + print_usage(argv); + exit(EXIT_FAILURE); + break; + } + } + if (first_host_in_list == NULL) { + fprintf(stderr, "ERROR: Unable to parse a config file.\n"); + exit(EXIT_FAILURE); } - va_end(ap); } -static int gcd(int x, int y) +int +main(int argc, char ** argv) { - while(x!=y) - { - if(x