/* Unix SMB/CIFS implementation. DNS server handler for queries Copyright (C) 2010 Kai Blin 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 GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see . */ #include "includes.h" #include "libcli/util/werror.h" #include "librpc/ndr/libndr.h" #include "librpc/gen_ndr/ndr_dns.h" #include "librpc/gen_ndr/ndr_dnsp.h" #include #include "dsdb/samdb/samdb.h" #include "dsdb/common/util.h" #include "dns_server/dns_server.h" #include "libcli/dns/libdns.h" static WERROR create_response_rr(const struct dns_name_question *question, const struct dnsp_DnssrvRpcRecord *rec, struct dns_res_rec **answers, uint16_t *ancount) { struct dns_res_rec *ans = *answers; uint16_t ai = *ancount; char *tmp; uint32_t i; ZERO_STRUCT(ans[ai]); switch (rec->wType) { case DNS_QTYPE_CNAME: ans[ai].rdata.cname_record = talloc_strdup(ans, rec->data.cname); break; case DNS_QTYPE_A: ans[ai].rdata.ipv4_record = talloc_strdup(ans, rec->data.ipv4); break; case DNS_QTYPE_AAAA: ans[ai].rdata.ipv6_record = rec->data.ipv6; break; case DNS_TYPE_NS: ans[ai].rdata.ns_record = rec->data.ns; break; case DNS_QTYPE_SRV: ans[ai].rdata.srv_record.priority = rec->data.srv.wPriority; ans[ai].rdata.srv_record.weight = rec->data.srv.wWeight; ans[ai].rdata.srv_record.port = rec->data.srv.wPort; ans[ai].rdata.srv_record.target = rec->data.srv.nameTarget; break; case DNS_QTYPE_SOA: ans[ai].rdata.soa_record.mname = rec->data.soa.mname; ans[ai].rdata.soa_record.rname = rec->data.soa.rname; ans[ai].rdata.soa_record.serial = rec->data.soa.serial; ans[ai].rdata.soa_record.refresh = rec->data.soa.refresh; ans[ai].rdata.soa_record.retry = rec->data.soa.retry; ans[ai].rdata.soa_record.expire = rec->data.soa.expire; ans[ai].rdata.soa_record.minimum = rec->data.soa.minimum; break; case DNS_QTYPE_PTR: ans[ai].rdata.ptr_record = talloc_strdup(ans, rec->data.ptr); break; case DNS_QTYPE_TXT: tmp = talloc_asprintf(ans, "\"%s\"", rec->data.txt.str[0]); for (i=1; idata.txt.count; i++) { tmp = talloc_asprintf_append(tmp, " \"%s\"", rec->data.txt.str[i]); } ans[ai].rdata.txt_record.txt = tmp; break; default: DEBUG(0, ("Got unhandled type %u query.\n", rec->wType)); return DNS_ERR(NOT_IMPLEMENTED); } ans[ai].name = talloc_strdup(ans, question->name); ans[ai].rr_type = rec->wType; ans[ai].rr_class = DNS_QCLASS_IN; ans[ai].ttl = rec->dwTtlSeconds; ans[ai].length = UINT16_MAX; ai++; *answers = ans; *ancount = ai; return WERR_OK; } static WERROR ask_forwarder(TALLOC_CTX *mem_ctx, struct dns_name_question *question, struct dns_res_rec **answers, uint16_t *ancount, struct dns_res_rec **nsrecs, uint16_t *nscount, struct dns_res_rec **additional, uint16_t *arcount) { struct tevent_context *ev = tevent_context_init(mem_ctx); struct dns_name_packet *out_packet, *in_packet; uint16_t id = random(); DATA_BLOB out, in; enum ndr_err_code ndr_err; WERROR werr = WERR_OK; struct tevent_req *req; out_packet = talloc_zero(mem_ctx, struct dns_name_packet); W_ERROR_HAVE_NO_MEMORY(out_packet); out_packet->id = id; out_packet->operation |= DNS_OPCODE_QUERY | DNS_FLAG_RECURSION_DESIRED; out_packet->qdcount = 1; out_packet->questions = question; ndr_err = ndr_push_struct_blob(&out, mem_ctx, out_packet, (ndr_push_flags_fn_t)ndr_push_dns_name_packet); if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) { return DNS_ERR(SERVER_FAILURE); } /* FIXME: Don't hardcode this, get that from a configuration somewhere */ req = dns_udp_request_send(mem_ctx, ev, "127.0.0.1", out.data, out.length); W_ERROR_HAVE_NO_MEMORY(req); if(!tevent_req_poll(req, ev)) { return DNS_ERR(SERVER_FAILURE); } werr = dns_udp_request_recv(req, mem_ctx, &in.data, &in.length); W_ERROR_NOT_OK_RETURN(werr); in_packet = talloc_zero(mem_ctx, struct dns_name_packet); W_ERROR_HAVE_NO_MEMORY(in_packet); ndr_err = ndr_pull_struct_blob(&in, in_packet, in_packet, (ndr_pull_flags_fn_t)ndr_pull_dns_name_packet); if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) { return DNS_ERR(SERVER_FAILURE); } if (in_packet->id != id) { DEBUG(0, ("DNS packet id mismatch: 0x%0x, expected 0x%0x\n", in_packet->id, id)); return DNS_ERR(NAME_ERROR); } *ancount = in_packet->ancount; *answers = talloc_move(mem_ctx, &in_packet->answers); *nscount = in_packet->nscount; *nsrecs = talloc_move(mem_ctx, &in_packet->nsrecs); *arcount = in_packet->arcount; *additional = talloc_move(mem_ctx, &in_packet->additional); return werr; } static WERROR handle_question(struct dns_server *dns, TALLOC_CTX *mem_ctx, const struct dns_name_question *question, struct dns_res_rec **answers, uint16_t *ancount) { struct dns_res_rec *ans; WERROR werror; unsigned int ri; struct dnsp_DnssrvRpcRecord *recs; uint16_t rec_count, ai = 0; struct ldb_dn *dn = NULL; werror = dns_name2dn(dns, mem_ctx, question->name, &dn); W_ERROR_NOT_OK_RETURN(werror); werror = dns_lookup_records(dns, mem_ctx, dn, &recs, &rec_count); W_ERROR_NOT_OK_RETURN(werror); ans = talloc_zero_array(mem_ctx, struct dns_res_rec, rec_count); W_ERROR_HAVE_NO_MEMORY(ans); for (ri = 0; ri < rec_count; ri++) { if ((question->question_type != DNS_QTYPE_ALL) && (recs[ri].wType != question->question_type)) { continue; } werror = create_response_rr(question, &recs[ri], &ans, &ai); W_ERROR_NOT_OK_RETURN(werror); } if (ai == 0) { return DNS_ERR(NAME_ERROR); } *ancount = ai; *answers = ans; return WERR_OK; } WERROR dns_server_process_query(struct dns_server *dns, struct dns_request_state *state, TALLOC_CTX *mem_ctx, struct dns_name_packet *in, struct dns_res_rec **answers, uint16_t *ancount, struct dns_res_rec **nsrecs, uint16_t *nscount, struct dns_res_rec **additional, uint16_t *arcount) { uint16_t num_answers=0, num_nsrecs=0, num_additional=0; struct dns_res_rec *ans=NULL, *ns=NULL, *adds=NULL; WERROR werror; if (in->qdcount != 1) { return DNS_ERR(FORMAT_ERROR); } /* Windows returns NOT_IMPLEMENTED on this as well */ if (in->questions[0].question_class == DNS_QCLASS_NONE) { return DNS_ERR(NOT_IMPLEMENTED); } if (dns_authorative_for_zone(dns, in->questions[0].name)) { state->flags |= DNS_FLAG_AUTHORITATIVE; werror = handle_question(dns, mem_ctx, &in->questions[0], &ans, &num_answers); } else { DEBUG(2, ("I don't feel responsible for '%s', forwarding\n", in->questions[0].name)); werror = ask_forwarder(mem_ctx, &in->questions[0], &ans, &num_answers, &ns, &num_nsrecs, &adds, &num_additional); } W_ERROR_NOT_OK_GOTO(werror, query_failed); *answers = ans; *ancount = num_answers; /*FIXME: Do something for these */ *nsrecs = ns; *nscount = num_nsrecs; *additional = adds; *arcount = num_additional; return WERR_OK; query_failed: /*FIXME: add our SOA record to nsrecs */ return werror; }