/*************************************************************************** * Copyright (C) 2019 by John D. Robertson * * john@rrci.com * * * * This program is free software; you can redistribute it and/or modify * * it under the terms of the GNU General Public License as published by * * the Free Software Foundation; either version 3 of the License, or * * (at your option) any later version. * * * * This program is distributed in the hope that it will be useful, * * but WITHOUT ANY WARRANTY; without even the implied warranty of * * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * * * * You should have received a copy of the GNU General Public License * * along with this program; if not, write to the * * Free Software Foundation, Inc., * * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. * ***************************************************************************/ #define _GNU_SOURCE #include #include #include #include "ez_libc.h" #include "util.h" const static struct addrinfo rev_hints= { .ai_flags = AI_NUMERICHOST, /* doing reverse lookups */ .ai_family = AF_UNSPEC, /* Allow IPv4 or IPv6 */ .ai_socktype= SOCK_DGRAM, .ai_protocol= IPPROTO_UDP }; const static struct addrinfo fwd_hints= { .ai_family= AF_UNSPEC, /* Allow IPv4 or IPv6 */ .ai_socktype= SOCK_DGRAM, .ai_protocol= IPPROTO_UDP }; int main(int argc, char **argv) { int rtn= EXIT_FAILURE; const char *addr= NULL; static char hostBuf[PATH_MAX]; extern char *optarg; extern int optind, optopt; for(optind= 1; optind < argc; ++optind) { addr= argv[optind]; /*============ Reverse DNS lookup ================*/ /* Get a populated addrinfo object */ struct addrinfo *res= NULL; int rc= ez_getaddrinfo(addr, NULL, &rev_hints, &res); assert(0 == rc); assert(res && res->ai_addr && res->ai_addrlen); addrinfo_print(res, stdout); ez_fflush(stdout); /* Now do blocking reverse lookup */ rc= ez_getnameinfo(res->ai_addr, res->ai_addrlen, hostBuf, sizeof(hostBuf)-1, NULL, 0, NI_NAMEREQD); if(rc) { ez_fprintf(stdout, "%s\n", gai_strerror(rc)); continue; } ez_fprintf(stdout, "RevDNS= \"%s\"\n", hostBuf); ez_fflush(stdout); /*============ Forward DNS lookup ================*/ rc= ez_getaddrinfo(hostBuf, NULL, &fwd_hints, &res); const char *msg= NULL; if(rc) { ez_fprintf(stdout, "%s\n", gai_strerror(rc)); continue; } addrinfo_print(res, stdout); ez_fflush(stdout); } rtn= EXIT_SUCCESS; abort: return rtn; }