From 684f5d952a4ecfad2d2fad808498a87b5184035b Mon Sep 17 00:00:00 2001 From: Aaron Taylor Date: Sat, 21 Sep 2019 02:03:35 -0700 Subject: [PATCH] General cleanup while reading through icmpmonitor.c. --- icmpmonitor.c | 473 +++++++++++++++++++++----------------------------- 1 file changed, 200 insertions(+), 273 deletions(-) diff --git a/icmpmonitor.c b/icmpmonitor.c index 64fa630..d222d61 100644 --- a/icmpmonitor.c +++ b/icmpmonitor.c @@ -7,117 +7,92 @@ * See LICENSE file for copyright and license details. */ -#include #include #include -#include #include #include #include #include #include #include -#include -#include #include -#include #include #include #include -#include #include #include -#include #include #include "cfg.h" -#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" - -# define icmphdr icmp - -/* typedefs */ -typedef struct monitor_host -{ - /* following are coming from cfg */ - char *name; +struct monitor_host { + /* 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 * upcmd; + char * downcmd; + + /* Calculated values */ + int socket; + struct timeval last_ping_received; + struct timeval last_ping_sent; + /* TODO: Replace the following two values with a single boolean */ + int up; + int down; struct sockaddr_in dest; - - unsigned int sentpackets ; - unsigned int recvdpackets; + unsigned int sentpackets; + unsigned int recvdpackets; /* linked list */ - struct monitor_host *next; -} monitor_host_t; + struct monitor_host * next; +}; /* protos */ -static int gethostaddr(const char *name); -static void read_hosts(const char *cfg_file_name); +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); +static int in_cksum(unsigned short * addr, int len); +static void read_icmp_data(struct monitor_host * 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; - - - - - - - - - - - - - -int main(int ac, char **av) +static struct monitor_host ** hosts = NULL; +static int isVerbose = 0; +static int keepBanging = 0; +static unsigned short ident; +static int send_delay = 1; + +int +main(int argc, char ** argv) { - 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); - } + extern char * optarg; + extern int optind; + char * cfgfile = NULL; + int param; + + while ((param = getopt(argc, argv, "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"); @@ -128,9 +103,9 @@ int main(int ac, char **av) init_hosts(); - ident=getpid() & 0xFFFF; + ident = getpid() & 0xFFFF; - (void)signal(SIGALRM, pinger); + signal(SIGALRM, pinger); alarm(send_delay); get_response(); @@ -138,173 +113,142 @@ int main(int ac, char **av) exit(EXIT_SUCCESS); } - /* - * in_cksum -- - * Checksum routine for Internet Protocol family headers (C Version) + * Checksum routine for Internet Protocol family headers */ static int -in_cksum(u_short *addr, int len) +in_cksum(unsigned short * addr, int len) { - register int nleft = len; - register u_short *w = addr; - register int sum = 0; - u_short answer = 0; + int nleft = len; + unsigned short * w = addr; + int sum = 0; + unsigned 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) { + while (nleft > 1) { sum += *w++; nleft -= 2; } /* mop up an odd byte, if necessary */ if (nleft == 1) { - *(u_char *)(&answer) = *(u_char *)w ; + *(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 */ + sum = (sum >> 16) + (sum & 0xffff); /* add hi 16 to low 16 */ + sum += (sum >> 16); /* add carry */ + answer = ~sum; /* truncate to 16 bits */ return(answer); } /* - * 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 + * 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. */ -static void pinger(int ignore) +static void +pinger(int ignore) { - 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) - { + int cc, i; + struct icmp * icp; + struct monitor_host * p; + u_char outpack[MAXPACKETSIZE]; + + p = hosts[0]; + while (p) { + if (p->socket != -1) { struct timeval now; - (void)gettimeofday(&now,(struct timezone *)NULL); + 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 (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()) - { + if (!fork()) { system(p->downcmd); - exit(0); - } else - { + exit(EXIT_SUCCESS); + } else { wait(NULL); } } } - (void)gettimeofday(&now,(struct timezone *)NULL); + 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; + if (now.tv_sec > p->ping_interval) { /* Time to send ping */ + icp = (struct icmp *) outpack; icp->icmp_type = ICMP_ECHO; icp->icmp_code = 0; icp->icmp_cksum = 0; icp->icmp_seq = p->socket; - icp->icmp_id = ident; + 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); + gettimeofday((struct timeval *) &outpack[8], (struct timezone *) NULL); - cc = DEFDATALEN + 8; /* skips ICMP portion */ + cc = DEFAULTDATALEN + 8; /* skips ICMP portion */ - /* compute ICMP checksum here */ - icp->icmp_cksum = in_cksum((u_short *)icp, cc); + /* compute ICMP checksum */ + icp->icmp_cksum = in_cksum((unsigned short *) icp, cc); - i = sendto(p->socket, (char *)outpack, cc, 0, (const struct sockaddr *)(&p->dest), - sizeof(struct sockaddr)); + 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); + gettimeofday(&p->last_ping_sent, (struct timezone *) NULL); - if(i<0 || i!=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; - + p = p->next; } - (void)signal(SIGALRM, pinger); /* restore handler */ + signal(SIGALRM, pinger); /* restore handler */ alarm(send_delay); } -static void get_response(void) +static void +get_response(void) { fd_set rfds; - int retval; - monitor_host_t *p; - int maxd=-1; + int retval, maxd = -1; + struct monitor_host * p; - while(1) - { - p=hosts[0]; + while (1) { + p = hosts[0]; FD_ZERO(&rfds); - while(p) - { - if(p->socket != -1) - { - if(p->socket > maxd) - maxd=p->socket; + while (p) { + if (p->socket != -1) { + if (p->socket > maxd) maxd=p->socket; FD_SET(p->socket, &rfds); } p=p->next; } 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; + if (retval < 0) { + /* Intentionally empty. We arrive here when interrupted by a signal. No action should be taken. */ + } else { + if (retval > 0) { + p = hosts[0]; + 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? */ @@ -313,19 +257,18 @@ static void get_response(void) } } -static void read_icmp_data(monitor_host_t *p) +static void +read_icmp_data(struct monitor_host * p) { - socklen_t fromlen ; - struct sockaddr_in from ; - int cc ; - struct ip *ip ; - struct icmp *icmp ; - int iphdrlen ; - int delay ; + int cc, iphdrlen, delay; + socklen_t fromlen; + struct sockaddr_in from; + struct ip * ip; + struct icmp * icmp; struct timeval tv ; - unsigned char buf[MAXPACKET]; /* read buffer */ + unsigned char buf[MAXPACKETSIZE]; - (void)gettimeofday(&tv, (struct timezone *)NULL); + gettimeofday(&tv, (struct timezone *) NULL); fromlen = sizeof(from); if ((cc = recvfrom(p->socket, buf, sizeof(buf), 0, (struct sockaddr *)&from, &fromlen)) < 0) { @@ -334,38 +277,32 @@ static void read_icmp_data(monitor_host_t *p) } /* check IP header actual len */ - ip = (struct ip *)buf ; - iphdrlen = ip->ip_hl<<2 ; - icmp = (struct icmp *) (buf+iphdrlen) ; + 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) - { + 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); + 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: 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()) - { + if (!fork()) { system(p->upcmd); - exit(0); - } else - { + exit(EXIT_SUCCESS); + } else { wait(NULL); } } @@ -374,10 +311,11 @@ static void read_icmp_data(monitor_host_t *p) } } -static void read_hosts(const char *cfg_file_name) +static void +read_hosts(const char * cfg_file_name) { - int i,n=0; - struct Cfg *cfg; + int i, n = 0; + struct Cfg * cfg; if ((cfg = readcfg(cfg_file_name)) == NULL) { fprintf(stderr, "ERROR: Failed to read config.\n"); @@ -385,8 +323,8 @@ static void read_hosts(const char *cfg_file_name) } if (cfg->nelements) { - hosts = malloc(sizeof(monitor_host_t *) * cfg->nelements); - for (i=0; inelements; i++) { + 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); @@ -395,37 +333,32 @@ static void read_hosts(const char *cfg_file_name) exit(EXIT_FAILURE); } - hosts[n] = malloc(sizeof(monitor_host_t)); + 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]->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); - } + 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 %d for startup condition.\n", cfg->dict[i]->value[4], n); + exit(EXIT_FAILURE); + } hosts[n]->sentpackets = 0; hosts[n]->recvdpackets = 0; @@ -446,80 +379,74 @@ static void read_hosts(const char *cfg_file_name) } } -static int gethostaddr(const char *name) +static int +gethostaddr(const char * name) { - static int res; - struct hostent *he; + 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 ); + if ((res = inet_addr(name)) < 0) { + he = gethostbyname(name); + if (!he) return -1; + memcpy(&res, he->h_addr, he->h_length); } return(res); } -static void init_hosts(void) +static void +init_hosts(void) { - monitor_host_t *p=hosts[0]; - struct protoent *proto; - int ok=0; + struct monitor_host * p = hosts[0]; + struct protoent * proto; + int ok = 0; 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) - { + 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) - { + } 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); + } else { + if (ok == 0) send_delay = p->ping_interval; + else send_delay = gcd(send_delay, p->ping_interval); ok++; } } - p=p->next; + p = p->next; } - if(!ok) - { + if (!ok) { fprintf(stderr, "ERROR: No hosts left to process.\n"); exit(EXIT_FAILURE); } } /* - * tvsub -- - * Subtract 2 timeval structs: out = out - in. Out is assumed to - * be >= in. + * Subtracts two timeval structs. + * Ensure out >= in. + * Modifies out = out - in. */ static void -tvsub(register struct timeval *out, register struct timeval *in) +tvsub(register struct timeval * out, register struct timeval * in) { - if ((out->tv_usec -= in->tv_usec) < 0) { - --out->tv_sec; - out->tv_usec += 1000000; - } - out->tv_sec -= in->tv_sec; + if ((out->tv_usec -= in->tv_usec) < 0) { + --out->tv_sec; + out->tv_usec += 1000000; + } + out->tv_sec -= in->tv_sec; } -static int gcd(int x, int y) +static int +gcd(int x, int y) { int remainder = x % y; if (remainder == 0) return y; -- 2.20.1