/*
- * 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 <netinet/ip_icmp.h>
#include <errno.h>
-#include "cfg.h"
+#include "iniparser/iniparser.h"
+
+#define VERSION 2
#define MAXPACKETSIZE (65536 - 60 - 8) /* TODO: What are the magic numbers? */
#define DEFAULTDATALEN (64 - 8) /* TODO: What are the magic numbers? */
+/* 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 monitor_host {
/* From the config file */
char * name;
int ping_interval;
int max_delay;
- char * upcmd;
- char * downcmd;
+ char * up_cmd;
+ char * down_cmd;
/* Calculated values */
int socket;
struct timeval last_ping_received;
struct timeval last_ping_sent;
- bool hostup;
+ bool host_up;
struct sockaddr_in dest;
- unsigned int sentpackets;
- unsigned int recvdpackets;
- /* linked list */
+ /* TODO: Why are we using both a linked list AND an array for this data? */
+ /* Linked list */
struct monitor_host * next;
};
-/* globals */
-static struct monitor_host ** hosts = NULL;
-static int isVerbose = 0;
-static int keepBanging = 0;
-static int send_delay = 1;
+/* Globals */
+ /* Since the program is based around signals, a linked list of hosts is maintained here. */
+ static struct monitor_host ** hosts = NULL;
+ /* Set by command line flags. */
+ static bool verbose = false;
+ static bool retry_down_cmd = false;
+ /* TODO: Get rid of this global. */
+ static int send_delay = 1;
/*
* Checksum routine for Internet Protocol family headers
* Modifies out = out - in.
*/
static void
-tvsub(register struct timeval * out, register struct timeval * in)
+tv_sub(register struct timeval * out, register struct timeval * in)
{
if ((out->tv_usec -= in->tv_usec) < 0) {
--out->tv_sec;
static void
pinger(int ignore)
{
- int cc, i;
+ int i;
struct icmp * icp;
struct monitor_host * p;
u_char outpack[MAXPACKETSIZE];
struct timeval now;
gettimeofday(&now, (struct timezone *) NULL);
- tvsub(&now, &p->last_ping_received);
+ tv_sub(&now, &p->last_ping_received);
if (now.tv_sec > (p->max_delay + p->ping_interval)) {
- if ((p->hostup) || keepBanging) {
- if (isVerbose) printf("INFO: Host %s stopped responding. Executing DOWN command.\n", p->name);
- p->hostup = false;
+ if ((p->host_up) || retry_down_cmd) {
+ if (verbose) printf("INFO: Host %s stopped responding. Executing DOWN command.\n", p->name);
+ p->host_up = false;
if (!fork()) {
- system(p->downcmd);
+ system(p->down_cmd);
exit(EXIT_SUCCESS);
} else {
wait(NULL);
}
gettimeofday(&now, (struct timezone *) NULL);
- tvsub(&now, &p->last_ping_sent);
+ tv_sub(&now, &p->last_ping_sent);
if (now.tv_sec > p->ping_interval) { /* Time to send ping */
icp = (struct icmp *) outpack;
icp->icmp_seq = p->socket;
icp->icmp_id = getpid() & 0xFFFF;
- if (isVerbose) printf("INFO: Sending ICMP packet to %s.\n", p->name);
+ if (verbose) printf("INFO: Sending ICMP packet to %s.\n", p->name);
gettimeofday((struct timeval *) &outpack[8], (struct timezone *) NULL);
- cc = DEFAULTDATALEN + 8; /* skips ICMP portion */
+ int cc = DEFAULTDATALEN + 8; /* skips ICMP portion */
/* compute ICMP checksum */
icp->icmp_cksum = in_cksum((unsigned short *) icp, cc);
if (i < 0 || i != cc) {
if (i<0) fprintf(stderr, "WARN: Failed sending ICMP packet to %s.\n", p->name);
}
- p->sentpackets++;
}
}
p = p->next;
}
if (icmp->icmp_type == ICMP_ECHOREPLY && icmp->icmp_id == (getpid() & 0xFFFF) && icmp->icmp_seq == p->socket) {
- p->recvdpackets++;
memcpy(&p->last_ping_received, &tv, sizeof(tv));
- tvsub(&tv, (struct timeval *) &icmp->icmp_data[0]);
+ tv_sub(&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);
- if (!p->hostup) {
- if (isVerbose) printf("INFO: Host %s started responding. Executing UP command.\n", p->name);
- p->hostup = true;
+ if (verbose) printf("INFO: Got ICMP reply from %s in %d ms.\n", p->name, delay);
+ 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->upcmd);
+ system(p->up_cmd);
exit(EXIT_SUCCESS);
} else {
wait(NULL);
FD_ZERO(&rfds);
while (p) {
if (p->socket != -1) {
- if (p->socket > maxd) maxd=p->socket;
+ if (p->socket > maxd) maxd = p->socket;
FD_SET(p->socket, &rfds);
}
p = p->next;
}
static void
-read_hosts(const char * cfg_file_name)
+parse_config(const char * conf_file)
{
- int i, n = 0;
- struct Cfg * cfg;
+ 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 ((cfg = readcfg(cfg_file_name)) == NULL) {
- fprintf(stderr, "ERROR: Failed to read config.\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);
}
- if (cfg->nelements) {
- hosts = malloc(sizeof(struct monitor_host *) * 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);
- }
+ hosts = malloc(sizeof(struct monitor_host *) * host_count);
+ 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++] = ':';
- hosts[n] = malloc(sizeof(struct monitor_host));
- 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]->hostup = true;
- } else if (strcmp(cfg->dict[i]->value[4], "up") == 0) {
- hosts[n]->hostup = true;
- } else if (strcmp(cfg->dict[i]->value[4], "down") == 0) {
- hosts[n]->hostup = false;
- } else if (strcmp(cfg->dict[i]->value[4], "auto") == 0) {
- /* TODO: Send a ping and set initial state accordingly. */
- } else {
- fprintf(stderr, "ERROR: Illegal value %s in record %d for startup condition.\n", cfg->dict[i]->value[4], n);
- exit(EXIT_FAILURE);
- }
- hosts[n]->sentpackets = 0;
- hosts[n]->recvdpackets = 0;
+ hosts[i] = malloc(sizeof(struct monitor_host));
- 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);
+ key_buf[section_len] = '\0';
+ strncat(key_buf, "host", MAXCONFKEYLEN);
+ hosts[i]->name = strdup(iniparser_getstring(conf, key_buf, NULL));
- n++;
- }
- }
+ key_buf[section_len] = '\0';
+ strncat(key_buf, "interval", MAXCONFKEYLEN);
+ hosts[i]->ping_interval = iniparser_getint(conf, key_buf, -1);
- freecfg(cfg);
+ key_buf[section_len] = '\0';
+ strncat(key_buf, "max_delay", MAXCONFKEYLEN);
+ hosts[i]->max_delay = iniparser_getint(conf, key_buf, -1);
- if (n <= 0) {
- fprintf(stderr, "ERROR: No hosts defined in cfg file, exiting.\n");
- exit(EXIT_FAILURE);
+ key_buf[section_len] = '\0';
+ strncat(key_buf, "up_cmd", MAXCONFKEYLEN);
+ hosts[i]->up_cmd = strdup(iniparser_getstring(conf, key_buf, NULL));
+
+ key_buf[section_len] = '\0';
+ strncat(key_buf, "down_cmd", MAXCONFKEYLEN);
+ hosts[i]->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. */
+ hosts[i]->host_up = true;
+
+ /* TODO: Do I want to make any checks for start_condition? */
+ if (hosts[i]->name == NULL || hosts[i]->ping_interval == -1 || hosts[i]->max_delay == -1) {
+ fprintf(stderr, "ERROR: Problems parsing section %s.\n", iniparser_getsecname(conf, i));
+ exit(EXIT_FAILURE);
+ }
+
+ hosts[i]->socket = -1;
+ hosts[i]->next = NULL;
+ if (i>0) hosts[i-1]->next = hosts[i];
+ gettimeofday(&(hosts[i]->last_ping_received), (struct timezone *) NULL);
}
+ iniparser_freedict(conf);
}
static int
-gethostaddr(const char * name)
+get_host_addr(const char * name)
{
static int res;
- struct hostent * he;
+ struct hostent * host_ent;
if ((res = inet_addr(name)) < 0) {
- he = gethostbyname(name);
- if (!he) return -1;
- memcpy(&res, he->h_addr, he->h_length);
+ host_ent = gethostbyname(name);
+ if (!host_ent) return -1;
+ memcpy(&res, host_ent->h_addr, host_ent->h_length);
}
return(res);
}
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) {
+ if ((p->dest.sin_addr.s_addr = get_host_addr(p->name)) <= 0) {
fprintf(stderr, "WARN: Can't resolve host. Skipping client %s.\n", p->name);
p->socket=-1;
} else {
}
}
-int
-main(int argc, char ** argv)
+void
+print_usage(char ** argv)
{
- extern char * optarg;
- extern int optind;
- char * cfgfile = NULL;
- int param;
+ 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]);
+}
- while ((param = getopt(argc, argv, "rvf:")) != -1) {
+void
+parse_params(int argc, char ** argv)
+{
+ int param;
+ while ((param = getopt(argc, argv, "hrvf:")) != -1) {
switch(param) {
case 'v':
- isVerbose = 1;
+ verbose = true;
break;
case 'r':
- keepBanging = 1;
+ retry_down_cmd = true;
break;
case 'f':
- cfgfile=strdup(optarg);
+ parse_config(optarg);
break;
+ case 'h':
default:
- fprintf(stderr,"Usage: icmpmonitor [-v] [-r] [-f cfgfile]\n");
+ print_usage(argv);
exit(EXIT_FAILURE);
+ break;
}
}
-
- if (!cfgfile) {
- fprintf(stderr, "ERROR: No config file specified.\n");
+ if (hosts == NULL) {
+ fprintf(stderr, "ERROR: Unable to parse a config file.\n");
exit(EXIT_FAILURE);
}
+}
- read_hosts(cfgfile);
+int
+main(int argc, char ** argv)
+{
+ parse_params(argc, argv);
init_hosts();