Created
October 24, 2014 08:37
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Testing DNS stub resolver (getaddrinfo(3))
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| #include <stdio.h> | |
| #include <string.h> | |
| #include <netdb.h> | |
| #include <arpa/inet.h> | |
| #include <errno.h> | |
| int main(int argc, char **argv) | |
| { | |
| struct addrinfo hints, *ai, *ai_p; | |
| const char *name; | |
| char addr[NI_MAXHOST]; | |
| int err; | |
| if (argc != 2) { | |
| printf("Usage: %s NAME\n", argv[0]); | |
| return 1; | |
| } | |
| name = argv[1]; | |
| memset(&hints, 0, sizeof(hints)); | |
| hints.ai_family = AF_UNSPEC; | |
| hints.ai_socktype = SOCK_STREAM; | |
| err = getaddrinfo(name, NULL, &hints, &ai); | |
| if (err) { | |
| fprintf(stderr, "%s: ERROR: %s\n", argv[0], gai_strerror(err)); | |
| return 1; | |
| } | |
| for (ai_p = ai; ai_p; ai_p = ai_p->ai_next){ | |
| void *ia; | |
| switch (ai_p->ai_family) { | |
| case AF_INET: | |
| ia = &((struct sockaddr_in *)(ai_p->ai_addr))->sin_addr.s_addr; | |
| break; | |
| case AF_INET6: | |
| ia = &((struct sockaddr_in6 *)(ai_p->ai_addr))->sin6_addr; | |
| break; | |
| default: | |
| fprintf(stderr, "%s: ERROR: Unknown address family: %d\n", argv[0], ai_p->ai_family); | |
| continue; | |
| } | |
| if (inet_ntop(ai_p->ai_family, ia, addr, sizeof(addr)) == NULL) { | |
| fprintf(stderr, "%s: ERROR: inet_ntop() failed: %s\n", argv[0], strerror(errno)); | |
| continue; | |
| } | |
| printf("%s\n", addr); | |
| } | |
| freeaddrinfo(ai); | |
| return 0; | |
| } |
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