diff options
| -rw-r--r-- | source4/dns_server/dns_query.c | 154 |
1 files changed, 111 insertions, 43 deletions
diff --git a/source4/dns_server/dns_query.c b/source4/dns_server/dns_query.c index 3564140948..fe4e13119f 100644 --- a/source4/dns_server/dns_query.c +++ b/source4/dns_server/dns_query.c @@ -32,6 +32,7 @@ #include "dns_server/dns_server.h" #include "libcli/dns/libdns.h" #include "lib/util/util_net.h" +#include "lib/util/tevent_werror.h" static WERROR create_response_rr(const struct dns_name_question *question, const struct dnsp_DnssrvRpcRecord *rec, @@ -128,66 +129,103 @@ static WERROR create_response_rr(const struct dns_name_question *question, return WERR_OK; } -static WERROR ask_forwarder(struct dns_server *dns, - 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 ask_forwarder_state { + struct tevent_context *ev; + uint16_t id; + struct dns_name_packet in_packet; +}; + +static void ask_forwarder_done(struct tevent_req *subreq); + +static struct tevent_req *ask_forwarder_send( + TALLOC_CTX *mem_ctx, struct tevent_context *ev, + const char *forwarder, struct dns_name_question *question) { - 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; + struct tevent_req *req, *subreq; + struct ask_forwarder_state *state; + struct dns_name_packet out_packet = { 0, }; + DATA_BLOB out_blob; enum ndr_err_code ndr_err; - WERROR werr = WERR_OK; - struct tevent_req *req; - const char *forwarder = lpcfg_dns_forwarder(dns->task->lp_ctx); + + req = tevent_req_create(mem_ctx, &state, struct ask_forwarder_state); + if (req == NULL) { + return NULL; + } + state->ev = ev; + generate_random_buffer((uint8_t *)&state->id, sizeof(state->id)); if (!is_ipaddress(forwarder)) { DEBUG(0, ("Invalid 'dns forwarder' setting '%s', needs to be " "an IP address\n", forwarder)); - return DNS_ERR(NAME_ERROR); + tevent_req_werror(req, DNS_ERR(NAME_ERROR)); + return tevent_req_post(req, ev); } - 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.id = state->id; + out_packet.operation |= DNS_OPCODE_QUERY | DNS_FLAG_RECURSION_DESIRED; + out_packet.qdcount = 1; + out_packet.questions = question; - 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); + ndr_err = ndr_push_struct_blob( + &out_blob, state, &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); + tevent_req_werror(req, DNS_ERR(SERVER_FAILURE)); + return tevent_req_post(req, ev); } - - req = dns_udp_request_send(mem_ctx, ev, forwarder, out.data, out.length); - W_ERROR_HAVE_NO_MEMORY(req); - - if(!tevent_req_poll(req, ev)) { - return DNS_ERR(SERVER_FAILURE); + subreq = dns_udp_request_send(state, ev, forwarder, out_blob.data, + out_blob.length); + if (tevent_req_nomem(subreq, req)) { + return tevent_req_post(req, ev); } + tevent_req_set_callback(subreq, ask_forwarder_done, req); + return req; +} - werr = dns_udp_request_recv(req, mem_ctx, &in.data, &in.length); - W_ERROR_NOT_OK_RETURN(werr); +static void ask_forwarder_done(struct tevent_req *subreq) +{ + struct tevent_req *req = tevent_req_callback_data( + subreq, struct tevent_req); + struct ask_forwarder_state *state = tevent_req_data( + req, struct ask_forwarder_state); + DATA_BLOB in_blob; + enum ndr_err_code ndr_err; + WERROR ret; - in_packet = talloc_zero(mem_ctx, struct dns_name_packet); - W_ERROR_HAVE_NO_MEMORY(in_packet); + ret = dns_udp_request_recv(subreq, state, + &in_blob.data, &in_blob.length); + TALLOC_FREE(subreq); + if (tevent_req_werror(req, ret)) { + return; + } - ndr_err = ndr_pull_struct_blob(&in, in_packet, in_packet, - (ndr_pull_flags_fn_t)ndr_pull_dns_name_packet); + ndr_err = ndr_pull_struct_blob( + &in_blob, state, &state->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); + tevent_req_werror(req, DNS_ERR(SERVER_FAILURE)); + return; } + if (state->in_packet.id != state->id) { + tevent_req_werror(req, DNS_ERR(NAME_ERROR)); + return; + } + tevent_req_done(req); +} - 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); +static WERROR ask_forwarder_recv( + struct tevent_req *req, TALLOC_CTX *mem_ctx, + 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 ask_forwarder_state *state = tevent_req_data( + req, struct ask_forwarder_state); + struct dns_name_packet *in_packet = &state->in_packet; + WERROR err; + + if (tevent_req_is_werror(req, &err)) { + return err; } *ancount = in_packet->ancount; @@ -199,7 +237,37 @@ static WERROR ask_forwarder(struct dns_server *dns, *arcount = in_packet->arcount; *additional = talloc_move(mem_ctx, &in_packet->additional); - return werr; + return WERR_OK; +} + +static WERROR ask_forwarder(struct dns_server *dns, + 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; + struct tevent_req *req; + WERROR err = WERR_NOMEM; + + ev = tevent_context_init(talloc_tos()); + if (ev == NULL) { + goto fail; + } + req = ask_forwarder_send( + ev, ev, lpcfg_dns_forwarder(dns->task->lp_ctx), question); + if (req == NULL) { + goto fail; + } + if (!tevent_req_poll_werror(req, ev, &err)) { + goto fail; + } + err = ask_forwarder_recv(req, mem_ctx, answers, ancount, + nsrecs, nscount, additional, arcount); +fail: + TALLOC_FREE(ev); + return err; } static WERROR handle_question(struct dns_server *dns, |