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prog.c
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prog.c
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#include "prog.h"
int main(int argc, char *argv[]){
int ch;
bool transportProtocolTCP = false;
bool transportProtocolUDP = false;
bool hexOutput = false;
bool hostByteOrder = false;
bool networkByteOrder = false;
bool IPv4 = false;
bool IPv6 = false;
bool reverseLookup = false;
//default
transportProtocolTCP = true;
hostByteOrder = true;
IPv4 = true;
if(argc == 1){
errx(1, "prog [-r] [-t|-u] [-x] [-h|-n] [-46] {hostname|IP_address} {servicename|port}");
}
while((ch = getopt(argc, argv, "rtuxhn46")) != -1){
switch (ch) {
case 't':
transportProtocolTCP = true;
transportProtocolUDP = false;
break;
case 'u':
transportProtocolTCP = false;
transportProtocolUDP = true;
break;
case 'x':
hexOutput = true;
break;
case 'h':
hostByteOrder = true;
networkByteOrder = false;
break;
case 'n':
hostByteOrder = false;
networkByteOrder = true;
break;
case '4':
IPv4 = true;
IPv6 = false;
break;
case '6':
IPv4 = false;
IPv6 = true;
break;
case 'r':
reverseLookup = true;
break;
default:
return 1;
}
}
if(argc - optind != 2){
errx(1, "Two arguments are required {hostname|IP_address} {servicename|port}\nprog [-r] [-t|-u] [-x] [-h|-n] [-46] {hostname|IP_address} {servicename|port}");
}
if(reverseLookup){
char *IP_address = argv[optind];
int port = atoi(argv[optind + 1]);
char *protocol = transportProtocolTCP ? "tcp" : "udp";
struct servent *service = getservbyport(htons(port), protocol);
char *serviceName = service->s_name;
char host[NI_MAXHOST];
int error;
if(IPv4){
struct sockaddr_in sa;
sa.sin_family = AF_INET;
if(inet_pton(AF_INET, IP_address, &(sa.sin_addr)) != 1){
errx(1,"%s is not a valid IP address", IP_address);
}
error = getnameinfo((struct sockaddr *)&sa, sizeof(struct sockaddr_in), host, sizeof(host), NULL, 0, NI_NAMEREQD);
if(error) errx(1, "%s", gai_strerror(error));
printf("%s (%s) %s\n", IP_address, host, serviceName);
}else{ //IPv6
struct sockaddr_in6 sa6;
sa6.sin6_family = AF_INET6;
if(inet_pton(AF_INET6, IP_address, &(sa6.sin6_addr)) != 1){
errx(1,"%s is not a valid IP address", IP_address);
}
error = getnameinfo((struct sockaddr *)&sa6, sizeof(struct sockaddr_in6), host, sizeof(host), NULL, 0, NI_NAMEREQD);
if(error) errx(1, "%s", gai_strerror(error));
printf("%s (%s) %s\n", IP_address, host, serviceName);
}
}else {
struct addrinfo hints, *res, *p;
int error;
char ipstr[INET6_ADDRSTRLEN];
char portstr[6];
int port;
memset(&hints, 0, sizeof(hints));
hints.ai_family = (IPv4) ? AF_INET : AF_INET6;
hints.ai_flags |= AI_CANONNAME;
hints.ai_socktype = (transportProtocolTCP) ? SOCK_STREAM : SOCK_DGRAM;
char *hostname = argv[optind];
char *serviceName = argv[optind+1];
error = getaddrinfo(hostname, serviceName, &hints, &res);
if (error) errx(2, "%s", gai_strerror(error));
p = res;
while(res){
if(res->ai_family == AF_INET){
inet_ntop(res->ai_family, &((struct sockaddr_in *) res->ai_addr)->sin_addr, ipstr, sizeof(ipstr));
if(networkByteOrder){
port = ((struct sockaddr_in *) res->ai_addr)->sin_port;
}else{
port = ntohs(((struct sockaddr_in *) res->ai_addr)->sin_port);
}
} else if (res->ai_family == AF_INET6){
inet_ntop(res->ai_family, &((struct sockaddr_in6 *) res->ai_addr)->sin6_addr, ipstr, sizeof(ipstr));
if(networkByteOrder){
port = ((struct sockaddr_in6 *) res->ai_addr)->sin6_port;
}else{
port = ntohs(((struct sockaddr_in6 *) res->ai_addr)->sin6_port);
}
}
snprintf(portstr, sizeof(portstr), "%d", port);
if(!hexOutput){
printf("%s (%s) %s\n", ipstr, res->ai_canonname, portstr);
}else{
printf("%s (%s) %04X\n", ipstr, res->ai_canonname, port);
}
break;
}
freeaddrinfo(p);
}
return 0;
}