X-Git-Url: http://git.subgeniuskitty.com/icmpmonitor/.git/blobdiff_plain/2acd035ea47de409e1e613ba67d2263eec62bc7c..5cc080f4770b79865ee068046af1eecac151e464:/icmpmonitor.c diff --git a/icmpmonitor.c b/icmpmonitor.c index 365192f..fe7fb12 100644 --- a/icmpmonitor.c +++ b/icmpmonitor.c @@ -1,5 +1,6 @@ /* * Monitor hosts using ICMP "echo" and notify when down. + * TODO: Write a better description. * * © 2019 Aaron Taylor * © 1999 Vadim Zaliva @@ -23,38 +24,44 @@ #include #include #include - -#include "cfg.h" +#include "iniparser/iniparser.h" #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; + unsigned int sent_packets; + unsigned int recvd_packets; - /* linked list */ + /* Linked list */ struct monitor_host * next; }; -/* globals */ -static struct monitor_host ** hosts = NULL; -static bool verbose = false; -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 @@ -96,7 +103,7 @@ in_cksum(unsigned short * addr, int len) * 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; @@ -126,14 +133,14 @@ pinger(int ignore) 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 ((p->host_up) || retry_down_cmd) { if (verbose) printf("INFO: Host %s stopped responding. Executing DOWN command.\n", p->name); - p->hostup = false; + p->host_up = false; if (!fork()) { - system(p->downcmd); + system(p->down_cmd); exit(EXIT_SUCCESS); } else { wait(NULL); @@ -142,7 +149,7 @@ pinger(int ignore) } 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; @@ -168,7 +175,7 @@ pinger(int ignore) if (i < 0 || i != cc) { if (i<0) fprintf(stderr, "WARN: Failed sending ICMP packet to %s.\n", p->name); } - p->sentpackets++; + p->sent_packets++; } } p = p->next; @@ -208,19 +215,19 @@ read_icmp_data(struct monitor_host * p) } if (icmp->icmp_type == ICMP_ECHOREPLY && icmp->icmp_id == (getpid() & 0xFFFF) && icmp->icmp_seq == p->socket) { - p->recvdpackets++; + p->recvd_packets++; 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 (verbose) printf("INFO: Got ICMP reply from %s in %d ms.\n", p->name, delay); - if (!p->hostup) { + if (!p->host_up) { if (verbose) printf("INFO: Host %s started responding. Executing UP command.\n", p->name); - p->hostup = true; + p->host_up = true; if (!fork()) { - system(p->upcmd); + system(p->up_cmd); exit(EXIT_SUCCESS); } else { wait(NULL); @@ -266,69 +273,81 @@ get_response(void) } } +/* + * Parses `config_file` and creates relevant entries under the global variable `hosts`. + */ 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 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[i] = malloc(sizeof(struct monitor_host)); + for (int k=0; k<6; k++) { + key_buf[section_len] = '\0'; /* Reuse the section name and colon on each pass through this loop. */ + switch (k) { + case 0: + strncat(key_buf, "host", MAXCONFKEYLEN); + hosts[i]->name = strdup(iniparser_getstring(conf, key_buf, NULL)); + break; + case 1: + strncat(key_buf, "interval", MAXCONFKEYLEN); + hosts[i]->ping_interval = iniparser_getint(conf, key_buf, -1); + break; + case 2: + strncat(key_buf, "max_delay", MAXCONFKEYLEN); + hosts[i]->max_delay = iniparser_getint(conf, key_buf, -1); + break; + case 3: + strncat(key_buf, "up_cmd", MAXCONFKEYLEN); + hosts[i]->up_cmd = strdup(iniparser_getstring(conf, key_buf, NULL)); + break; + case 4: + strncat(key_buf, "down_cmd", MAXCONFKEYLEN); + hosts[i]->down_cmd = strdup(iniparser_getstring(conf, key_buf, NULL)); + break; + case 5: + /* TODO: Parse for up/down/auto in start_condition. */ + /* TODO: Do a host up/down check if necessary. */ + hosts[i]->host_up = true; + break; } - - 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[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++; + /* TODO: Do I want to make any checks for up_cmd, down_cmd, and 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); } - } - - freecfg(cfg); - if (n <= 0) { - fprintf(stderr, "ERROR: No hosts defined in cfg file, exiting.\n"); - exit(EXIT_FAILURE); + hosts[i]->sent_packets = 0; + hosts[i]->recvd_packets = 0; + 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; @@ -364,7 +383,7 @@ init_hosts(void) 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 { @@ -386,37 +405,42 @@ init_hosts(void) } } -int -main(int argc, char ** argv) +void +print_usage(void) { - extern char * optarg; - extern int optind; - char * cfgfile = NULL; - int param; + fprintf(stderr,"Usage: icmpmonitor [-v] [-r] [-f cfgfile]\n"); +} +void +parse_params(int argc, char ** argv) +{ + int param; while ((param = getopt(argc, argv, "rvf:")) != -1) { switch(param) { case 'v': verbose = true; break; case 'r': - keepBanging = 1; + retry_down_cmd = true; break; case 'f': - cfgfile=strdup(optarg); + parse_config(optarg); break; default: - fprintf(stderr,"Usage: icmpmonitor [-v] [-r] [-f cfgfile]\n"); + print_usage(); exit(EXIT_FAILURE); } } - - 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();