79 lines
2 KiB
C
79 lines
2 KiB
C
/*
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* getnameinfo(3) (address->name lookup) tester.
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*
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* Compile with:
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*
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* cc -o getnameinfo getnameinfo.c (BSD, Linux)
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*
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* cc -o getnameinfo getnameinfo.c -lsocket -lnsl (SunOS 5.x)
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*
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* Run as: getnameinfo address
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*
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* Author: Wietse Venema, Eindhoven University of Technology, The Netherlands.
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*
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* Author: Wietse Venema, IBM T.J. Watson Research, USA.
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*/
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <netdb.h>
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#include <stdio.h>
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#include <unistd.h>
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#include <string.h>
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#include <stdlib.h>
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int main(int argc, char **argv)
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{
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char hostbuf[NI_MAXHOST]; /* XXX */
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struct addrinfo hints;
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struct addrinfo *res0;
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struct addrinfo *res;
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const char *host;
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const char *addr;
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int err;
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#define NO_SERVICE ((char *) 0)
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if (argc != 2) {
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fprintf(stderr, "usage: %s ipaddress\n", argv[0]);
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exit(1);
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}
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/*
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* Convert address to internal form.
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*/
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host = argv[1];
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memset((char *) &hints, 0, sizeof(hints));
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hints.ai_family = (strchr(host, ':') ? AF_INET6 : AF_INET);
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hints.ai_socktype = SOCK_STREAM;
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hints.ai_flags |= AI_NUMERICHOST;
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if ((err = getaddrinfo(host, NO_SERVICE, &hints, &res0)) != 0) {
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fprintf(stderr, "getaddrinfo %s: %s\n", host, gai_strerror(err));
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exit(1);
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}
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/*
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* Convert host address to name.
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*/
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for (res = res0; res != 0; res = res->ai_next) {
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err = getnameinfo(res->ai_addr, res->ai_addrlen,
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hostbuf, sizeof(hostbuf),
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NO_SERVICE, 0, NI_NAMEREQD);
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if (err) {
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fprintf(stderr, "getnameinfo %s: %s\n", host, gai_strerror(err));
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exit(1);
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}
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printf("Hostname:\t%s\n", hostbuf);
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addr = (res->ai_family == AF_INET ?
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(char *) &((struct sockaddr_in *) res->ai_addr)->sin_addr :
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(char *) &((struct sockaddr_in6 *) res->ai_addr)->sin6_addr);
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if (inet_ntop(res->ai_family, addr, hostbuf, sizeof(hostbuf)) == 0) {
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perror("inet_ntop:");
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exit(1);
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}
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printf("Address:\t%s\n", hostbuf);
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}
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freeaddrinfo(res0);
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exit(0);
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}
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