La commande haah (host-address-address-host)
From Livre IPv6
Revision as of 19:15, 15 December 2005 by Laurent Toutain (Talk | contribs)
L'exemple proposé n'est autre qu'une sorte de nslookup (très) simplifié. Si par exemple on lui donne en argument une adresse numérique (IPv4 ou IPv6), il imprime le nom complètement qualifié correspondant lorsque la requête DNS aboutit. L'extrait de session qui suit illustre l'utilisation de cette commande.
$ haah bernays Canonical name: bernays.ipv6.logique.jussieu.fr Adresses: 2001:660:101:101:200:f8ff:fe31:17ec 3ffe:304:101:1:200:f8ff:fe31:17ec $ haah 134.157.19.71 Canonical name: bernays.logique.jussieu.fr Adresses: 134.157.19.71 $
Le programme réalisant la commande haah ne présente aucune difficulté. C'est une simple application des primitives précédemment décrites.
| # | #include <stdio.h> |
| # | |
| # | #include <string.h> |
| # | #include <errno.h> |
| # | #include <sys/types.h> |
| # | #include <sys/socket.h> |
| # | #include <netinet/in.h> |
| # | #include <netdb.h> |
| # | #include <arpa/inet.h> |
| # | |
| # | |
| # | int main(int argc, char **argv) |
| # | { |
| # | int ret; |
| # | struct addrinfo *res, *ptr; |
| # | struct addrinfo hints = { |
| # | AI_CANONNAME, |
| # | PF_UNSPEC, |
| # | SOCK_STREAM, |
| # | 0, |
| # | 0, |
| # | NULL, |
| # | NULL, |
| # | NULL |
| # | }; |
| # | |
| # | if (argc != 2) { |
| # | addr.\n", *argv, *argv); |
| # | exit(1); |
| # | } |
| # | ret = getaddrinfo(argv[1], NULL, &hints, &res); |
| # | if (ret) { |
| # | fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(ret)); |
| # | exit(1); |
| # | } |
| # | for (ptr = res; ptr; ptr = ptr->ai_next) { |
| # | if (ptr->ai_canonname) |
| # | fprintf(stdout,"Canonical name:\n%s\nAdresses:\n", ptr->ai_canonname); |
| # | switch (ptr->ai_family) { |
| # | case AF_INET: |
| # | { |
| # | char dst[INET_ADDRSTRLEN]; |
| # | struct in_addr *src = &((struct sockaddr_in *) ptr->ai_addr)->sin_addr; |
| # | |
| # | if(!inet_ntop(AF_INET, (const void *) src, dst, sizeof(dst))) { |
| # | fprintf(stderr, "inet_ntop: %s\n", strerror(errno)); |
| # | break; |
| # | } |
| # | fprintf(stdout, "%s\n", dst); |
| # | break; |
| # | } |
| # | case AF_INET6: |
| # | { |
| # | char dst[INET6_ADDRSTRLEN]; |
| # | struct in6_addr *src=&((struct sockaddr_in6 *)ptr->ai_addr)->sin6_addr; |
| # | |
| # | if (!inet_ntop(AF_INET6, (const void *) src, dst, sizeof(dst))) { |
| # | fprintf(stderr, "inet_ntop: %s\n", strerror(errno)); |
| # | break; |
| # | } |
| # | fprintf(stdout, "%s\n", dst); |
| # | break; |
| # | } |
| # | default: |
| # | fprintf(stderr, "getaddrinfo: %s\n", strerror(EAFNOSUPPORT)); |
| # | } |
| # | } |
| # | freeaddrinfo(res); |
| # | exit(0); |
| # | } |
