/*
- * Monitor hosts using ICMP "echo" and notify when down.
- *
+ * ICMPmonitor
+ *
+ * Monitors hosts using ICMP 'echo', executing a user-specified command
+ * whenever hosts change state between responsive and unresponsive.
+ *
* © 2019 Aaron Taylor <ataylor at subgeniuskitty dot com>
* © 1999 Vadim Zaliva <lord@crocodile.org>
* © 1989 The Regents of the University of California & Mike Muuss
+ *
* See LICENSE file for copyright and license details.
*/
-#include <sys/param.h>
+/* 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. */
+
#include <stdio.h>
#include <stdlib.h>
-#include <stdarg.h>
+#include <stdbool.h>
#include <signal.h>
#include <string.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <sys/socket.h>
#include <sys/types.h>
-#include <fcntl.h>
-#include <sys/fcntl.h>
#include <unistd.h>
-#include <sys/stat.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
-#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/ip_icmp.h>
-#include <stddef.h>
#include <errno.h>
+#include <assert.h>
-#include "cfg.h"
+#include "iniparser/iniparser.h"
-/* 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
+#define VERSION 2
-#define MAXPACKET (65536 - 60 - 8) /* max packet size */
-#define DEFDATALEN (64 - 8) /* default data length */
+#define MAXPACKETSIZE (65536 - 60 - 8) /* TODO: What are the magic numbers? */
+#define DEFAULTDATALEN (64 - 8) /* TODO: What are the magic numbers? */
-#define VERSION "ICMPmonitor v1.2 by lord@crocodile.org"
+/* 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
-# define icmphdr icmp
+/* 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
-/* typedefs */
-typedef struct monitor_host
-{
- /* following are coming from cfg */
- char *name;
+/* Must be larger than the length of the longest configuration key (currently 'start_condition'). */
+#define MAXCONFKEYLEN 20
+
+/* 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 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 int gcd(int x, int y);
-
-/* globals */
-
-static monitor_host_t **hosts = NULL;
-static int isVerbose = 0;
-static int keepBanging = 0;
-static unsigned short ident;
-static int send_delay = 1;
-
-
-
-
-
-
-
-
-
-
-
+ /* 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;
-int main(int ac, char **av)
+/*
+ * 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.
+ */
+uint16_t
+checksum(const uint16_t * data)
{
- extern char* optarg;
- extern int optind;
- char *cfgfile=NULL;
- int param;
-
- while((param = getopt(ac, av, "rvf:")) != -1)
- switch(param)
- {
- case 'v':
- isVerbose = 1;
- break;
- case 'r':
- keepBanging = 1;
- break;
- case 'f':
- cfgfile=strdup(optarg);
- break;
- default:
- fprintf(stderr,"Usage: icmpmonitor [-v] [-r] [-f cfgfile]\n");
- exit(EXIT_FAILURE);
- }
-
- if (!cfgfile) {
- fprintf(stderr, "ERROR: No config file specified.\n");
- exit(EXIT_FAILURE);
+ 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;
}
-
- read_hosts(cfgfile);
-
- init_hosts();
-
- ident=getpid() & 0xFFFF;
-
- (void)signal(SIGALRM, pinger);
- alarm(send_delay);
-
- get_response();
-
- exit(EXIT_SUCCESS);
+ return htons(~accumulator);
}
-
/*
- * in_cksum --
- * Checksum routine for Internet Protocol family headers (C Version)
+ * Calculate difference (a-b) between two timeval structs.
*/
-static int
-in_cksum(u_short *addr, int len)
+void
+timeval_diff(struct timeval * a, const struct timeval * b)
{
- 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;
+ if (a->tv_usec < b->tv_usec) {
+ a->tv_sec--;
+ a->tv_usec += 1000000;
}
-
- /* mop up an odd byte, if necessary */
- if (nleft == 1) {
- *(u_char *)(&answer) = *(u_char *)w ;
- sum += answer;
- }
-
- /* 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);
+ a->tv_usec -= b->tv_usec;
+ a->tv_sec -= b->tv_sec;
}
/*
- * 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.
+ * This function iterates over the list of hosts, pinging any which are due.
*/
-static void pinger(int ignore)
+void
+pinger(int ignore) /* Dummy parameter since this function registers as a signal handler. */
{
- 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) printf("INFO: Host %s is down. Executing DOWN command.\n", p->name);
- if(!fork())
- {
- system(p->downcmd);
- exit(0);
- } else
- {
- wait(NULL);
- }
- }
- }
-
- (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) printf("INFO: Sending ICMP packet to %s.\n", 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) fprintf(stderr, "WARN: Failed sending ICMP packet to %s.\n", p->name);
- }
- p->sentpackets++;
+ 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;
-
- }
-
- (void)signal(SIGALRM, pinger); /* restore handler */
- alarm(send_delay);
-}
-static void get_response(void)
-{
- 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);
- }
- p=p->next;
- }
+ if (elapsed_time.tv_sec > host->ping_interval) {
+ if (verbose) printf("INFO: Sending ICMP packet to %s.\n", host->name);
- retval = select(maxd+1, &rfds, NULL, NULL, NULL);
- if(retval<0)
- {
- /* we get her in case we are interrupted by signal.
- it's ok. */
- }
- else
- {
- if(retval>0)
- {
- p=hosts[0];
- while(p)
- {
- if(p->socket!=-1 && FD_ISSET(p->socket, &rfds))
- {
- /* Read data */
- read_icmp_data(p);
- }
- p=p->next;
- }
+ 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 {
- /* TODO: How to handle this error? */
+ 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)
+static void
+read_icmp_data(struct host_entry * p)
{
- 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);
-
+ int cc, iphdrlen, delay;
+ socklen_t fromlen;
+ struct sockaddr_in from;
+ struct ip * ip;
+ struct icmp * icmp;
+ struct timeval tv;
+ unsigned char buf[MAXPACKETSIZE];
+
+ 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) fprintf(stderr, "WARN: Error reading ICMP data from %s.\n", p->name);
return;
- }
+ }
+
+ /* check IP header actual len */
+ ip = (struct ip *) buf;
+ iphdrlen = ip->ip_hl << 2;
+ icmp = (struct icmp *) (buf + iphdrlen);
- /* check IP header actual len */
- ip = (struct ip *)buf ;
- iphdrlen = ip->ip_hl<<2 ;
- icmp = (struct icmp *) (buf+iphdrlen) ;
-
if (cc < iphdrlen + ICMP_MINLEN) {
fprintf(stderr, "WARN: Received short packet from %s.\n", p->name);
return;
}
-
- if(icmp->icmp_type == ICMP_ECHOREPLY &&
- icmp->icmp_id == ident &&
- icmp->icmp_seq == p->socket)
- {
- p->recvdpackets++;
+
+ if (icmp->icmp_type == ICMP_ECHOREPLY && icmp->icmp_id == (getpid() & 0xFFFF) && icmp->icmp_seq == p->socket) {
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) printf("INFO: Got ICMP reply from %s in %d ms.\n", p->name, delay);
- p->down=0;
- if(!p->up)
- {
- p->up=1;
- if (isVerbose) printf("INFO: Host %s is up. Executing UP command.\n", p->name);
- if(!fork())
- {
- system(p->upcmd);
- exit(0);
- } else
- {
+
+ timeval_diff(&tv, (struct timeval *) &icmp->icmp_data[0]);
+ delay = tv.tv_sec * 1000 + (tv.tv_usec / 1000);
+
+ if (verbose) printf("INFO: Got ICMP reply from %s.\n", p->name);
+ if (!p->host_up) {
+ if (verbose) printf("INFO: Host %s started responding. Executing UP command.\n", p->name);
+ p->host_up = true;
+ if (!fork()) {
+ system(p->up_cmd);
+ exit(EXIT_SUCCESS);
+ } else {
wait(NULL);
}
}
}
}
-static void read_hosts(const char *cfg_file_name)
+static void
+get_response(void)
{
- int i,n=0;
- struct Cfg *cfg;
-
- if ((cfg = readcfg(cfg_file_name)) == NULL) {
- fprintf(stderr, "ERROR: Failed to read config.\n");
- exit(EXIT_FAILURE);
- }
-
- if (cfg->nelements) {
- hosts = malloc(sizeof(monitor_host_t *) * cfg->nelements);
- for (i=0; i<cfg->nelements; i++) {
- if (cfg->dict[i]->nvalues < 4) {
- fprintf(stderr, "ERROR: Not enough fields in record %d of cfg file. Got %d.\n", n, cfg->dict[i]->nvalues+1);
- exit(EXIT_FAILURE);
- } else if (cfg->dict[i]->nvalues>5) {
- fprintf(stderr, "ERROR: Too many fields in record %d of cfg file. Got %d.\n", n, cfg->dict[i]->nvalues+1);
- exit(EXIT_FAILURE);
+ fd_set rfds;
+ int retval, maxd = -1;
+ struct host_entry * p;
+
+ while (1) {
+ p = first_host_in_list;
+ FD_ZERO(&rfds);
+ while (p) {
+ if (p->socket != -1) {
+ if (p->socket > maxd) maxd = p->socket;
+ FD_SET(p->socket, &rfds);
}
-
- 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 {
- fprintf(stderr, "ERROR: Illegal value %s in record %n for startup condition.\n", cfg->dict[i]->value[4], n);
- exit(EXIT_FAILURE);
- }
- hosts[n]->sentpackets = 0;
- hosts[n]->recvdpackets = 0;
-
- hosts[n]->socket = -1;
- hosts[n]->next = NULL;
- if (n > 0) hosts[n-1]->next=hosts[n];
- gettimeofday(&(hosts[n]->last_ping_received), (struct timezone *)NULL);
-
- n++;
- }
+ p = p->next;
+ }
+
+ retval = select(maxd+1, &rfds, NULL, NULL, NULL);
+ if (retval < 0) {
+ /* Intentionally empty. We arrive here when interrupted by a signal. No action should be taken. */
+ } else {
+ if (retval > 0) {
+ p = first_host_in_list;
+ while (p) {
+ if (p->socket!=-1 && FD_ISSET(p->socket, &rfds)) read_icmp_data(p);
+ p = p->next;
+ }
+ } else {
+ /* TODO: How to handle this error? */
+ }
+ }
}
+}
- freecfg(cfg);
+static void
+parse_config(const char * conf_file)
+{
+ dictionary * conf = iniparser_load(conf_file);
+ if (conf == NULL) {
+ fprintf(stderr, "ERROR: Unable to parse configuration file %s.\n", conf_file);
+ exit(EXIT_FAILURE);
+ }
- if (n <= 0) {
- fprintf(stderr, "ERROR: No hosts defined in cfg file, exiting.\n");
+ 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);
}
+
+ 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 + MAXCONFKEYLEN + 1);
+ 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", MAXCONFKEYLEN);
+ cur_host->name = strdup(iniparser_getstring(conf, key_buf, NULL));
+
+ key_buf[section_len] = '\0';
+ strncat(key_buf, "interval", MAXCONFKEYLEN);
+ cur_host->ping_interval = iniparser_getint(conf, key_buf, -1);
+
+ key_buf[section_len] = '\0';
+ strncat(key_buf, "max_delay", MAXCONFKEYLEN);
+ cur_host->max_delay = iniparser_getint(conf, key_buf, -1);
+
+ key_buf[section_len] = '\0';
+ strncat(key_buf, "up_cmd", MAXCONFKEYLEN);
+ cur_host->up_cmd = strdup(iniparser_getstring(conf, key_buf, NULL));
+
+ key_buf[section_len] = '\0';
+ strncat(key_buf, "down_cmd", MAXCONFKEYLEN);
+ cur_host->down_cmd = strdup(iniparser_getstring(conf, key_buf, NULL));
+
+ key_buf[section_len] = '\0';
+ /* TODO: Parse for up/down/auto in start_condition. */
+ /* TODO: Do a host up/down check if necessary. */
+ cur_host->host_up = true;
+
+ /* TODO: Do I want to make any checks for start_condition? */
+ 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;
+ }
+
+ free(key_buf);
+ }
+ iniparser_freedict(conf);
+}
+
+/*
+ * Parse string (IP or hostname) to Internet address.
+ *
+ * Returns 0 if host can't be resolved, otherwise returns an Internet address.
+ */
+uint32_t
+get_host_addr(const char * name)
+{
+ 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;
}
-static int gethostaddr(const char *name)
+size_t
+gcd(const size_t x, const size_t y)
{
- 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);
+ size_t remainder = x % y;
+ if (remainder == 0) return y;
+ return gcd(y, remainder);
+}
+
+void
+remove_host_from_list(struct host_entry * host)
+{
+ 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 init_hosts(void)
+void
+init_hosts(void)
{
- monitor_host_t *p=hosts[0];
- struct protoent *proto;
- int ok=0;
+ struct host_entry * host;
+ struct protoent * proto;
if ((proto = getprotobyname("icmp")) == NULL) {
fprintf(stderr, "ERROR: Unknown protocol: icmp.\n");
exit(EXIT_FAILURE);
}
-
- while(p) {
- bzero(&p->dest,sizeof(p->dest));
- p->dest.sin_family=AF_INET;
- if((p->dest.sin_addr.s_addr=gethostaddr(p->name))<=0)
- {
- fprintf(stderr, "WARN: Can't resolve host. Skipping client %s.\n", p->name);
- p->socket=-1;
- } else
- {
- if((p->socket=socket(AF_INET,SOCK_RAW,proto->p_proto))<0)
- {
- fprintf(stderr, "WARN: Can't create socket. Skipping client %s.\n", p->name);
- p->socket=-1;
- } else
- {
- if(ok==0)
- send_delay = p->ping_interval;
- else
- send_delay = gcd(send_delay, p->ping_interval);
- ok++;
- }
+
+ 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);
}
- p=p->next;
+ host = next_host;
}
- if(!ok)
- {
- fprintf(stderr, "ERROR: No hosts left to process.\n");
- exit(EXIT_FAILURE);
+ 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;
}
}
-/*
- * tvsub --
- * Subtract 2 timeval structs: out = out - in. Out is assumed to
- * be >= in.
- */
-static void
-tvsub(register struct timeval *out, register struct timeval *in)
+void
+print_usage(char ** argv)
{
- if ((out->tv_usec -= in->tv_usec) < 0) {
- --out->tv_sec;
- out->tv_usec += 1000000;
- }
- out->tv_sec -= in->tv_sec;
+ printf( "ICMPmonitor v%d (www.subgeniuskitty.com)\n"
+ "Usage: %s [-h] [-v] [-r] -f <file>\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 <file> Specify a configuration file.\n"
+ , VERSION, argv[0]);
}
-static int gcd(int x, int y)
+void
+parse_params(int argc, char ** argv)
{
- int remainder = x % y;
- if (remainder == 0) return y;
- return gcd(y, remainder);
+ 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);
+ }
+}
+
+int
+main(int argc, char ** argv)
+{
+ parse_params(argc, argv);
+
+ init_hosts();
+
+ signal(SIGALRM, pinger);
+ alarm(TIMER_RESOLUTION);
+
+ get_response();
+
+ exit(EXIT_SUCCESS);
}