99 lines
1.9 KiB
C
99 lines
1.9 KiB
C
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/*
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* Based on code found at https://dev.openwrt.org/ticket/4876 .
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* Extended by Jo-Philipp Wich <jow@openwrt.org> for use in OpenWrt.
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*
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* You may use this program under the terms of the GPLv2 license.
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*/
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#include <string.h>
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#include <stdio.h>
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <netdb.h>
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#include <arpa/inet.h>
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#include <netinet/in.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <signal.h>
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static void abort_query(int sig)
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{
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exit(1);
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}
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static void show_usage(void)
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{
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printf("Usage:\n");
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printf(" resolveip -h\n");
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printf(" resolveip [-t timeout] hostname\n");
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printf(" resolveip -4 [-t timeout] hostname\n");
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printf(" resolveip -6 [-t timeout] hostname\n");
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exit(255);
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}
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int main(int argc, char **argv)
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{
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int timeout = 3;
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char opt;
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char ipaddr[INET6_ADDRSTRLEN];
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void *addr;
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struct addrinfo *res, *rp;
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struct sigaction sa = { .sa_handler = &abort_query };
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struct addrinfo hints = {
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.ai_family = AF_UNSPEC,
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.ai_socktype = SOCK_STREAM,
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.ai_protocol = IPPROTO_TCP,
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.ai_flags = 0
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};
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while ((opt = getopt(argc, argv, "46t:h")) > -1)
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{
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switch (opt)
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{
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case '4':
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hints.ai_family = AF_INET;
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break;
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case '6':
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hints.ai_family = AF_INET6;
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break;
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case 't':
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timeout = atoi(optarg);
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if (timeout <= 0)
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show_usage();
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break;
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case 'h':
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show_usage();
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break;
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}
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}
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if (!argv[optind])
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show_usage();
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sigaction(SIGALRM, &sa, NULL);
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alarm(timeout);
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if (getaddrinfo(argv[optind], NULL, &hints, &res))
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exit(2);
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for (rp = res; rp != NULL; rp = rp->ai_next)
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{
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addr = (rp->ai_family == AF_INET)
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? (void *)&((struct sockaddr_in *)rp->ai_addr)->sin_addr
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: (void *)&((struct sockaddr_in6 *)rp->ai_addr)->sin6_addr
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;
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if (!inet_ntop(rp->ai_family, addr, ipaddr, INET6_ADDRSTRLEN - 1))
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exit(3);
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printf("%s\n", ipaddr);
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}
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freeaddrinfo(res);
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exit(0);
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}
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