diff options
Diffstat (limited to 'lib/addns/dnsquery.c')
| -rw-r--r-- | lib/addns/dnsquery.c | 782 |
1 files changed, 782 insertions, 0 deletions
diff --git a/lib/addns/dnsquery.c b/lib/addns/dnsquery.c new file mode 100644 index 0000000..869d459 --- /dev/null +++ b/lib/addns/dnsquery.c @@ -0,0 +1,782 @@ +/* + Unix SMB/CIFS implementation. + DNS utility library + Copyright (C) Gerald (Jerry) Carter 2006. + Copyright (C) Jeremy Allison 2007. + + 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 <http://www.gnu.org/licenses/>. +*/ + +#include "includes.h" +#include "lib/util/util_net.h" +#include "lib/util/tsort.h" +#include "librpc/gen_ndr/dns.h" +#include "libcli/dns/dns_lookup.h" +#include "lib/util/tevent_ntstatus.h" +#include "dnsquery.h" + +/********************************************************************* + Sort SRV record list based on weight and priority. See RFC 2782. +*********************************************************************/ + +static int dnssrvcmp( struct dns_rr_srv *a, struct dns_rr_srv *b ) +{ + if ( a->priority == b->priority ) { + + /* randomize entries with an equal weight and priority */ + if ( a->weight == b->weight ) + return 0; + + /* higher weights should be sorted lower */ + if ( a->weight > b->weight ) + return -1; + else + return 1; + } + + if ( a->priority < b->priority ) + return -1; + + return 1; +} + +struct ads_dns_lookup_srv_state { + struct dns_rr_srv *srvs; + size_t num_srvs; +}; + +static void ads_dns_lookup_srv_done(struct tevent_req *subreq); + +struct tevent_req *ads_dns_lookup_srv_send(TALLOC_CTX *mem_ctx, + struct tevent_context *ev, + const char *name) +{ + struct tevent_req *req, *subreq; + struct ads_dns_lookup_srv_state *state; + + req = tevent_req_create(mem_ctx, &state, + struct ads_dns_lookup_srv_state); + if (req == NULL) { + return NULL; + } + + subreq = dns_lookup_send( + state, + ev, + NULL, + name, + DNS_QCLASS_IN, + DNS_QTYPE_SRV); + + if (tevent_req_nomem(subreq, req)) { + return tevent_req_post(req, ev); + } + tevent_req_set_callback(subreq, ads_dns_lookup_srv_done, req); + return req; +} + +static void ads_dns_lookup_srv_done(struct tevent_req *subreq) +{ + struct tevent_req *req = tevent_req_callback_data( + subreq, struct tevent_req); + struct ads_dns_lookup_srv_state *state = tevent_req_data( + req, struct ads_dns_lookup_srv_state); + int ret; + struct dns_name_packet *reply; + uint16_t i, idx; + + ret = dns_lookup_recv(subreq, state, &reply); + TALLOC_FREE(subreq); + if (ret != 0) { + tevent_req_nterror(req, map_nt_error_from_unix_common(ret)); + return; + } + + for (i=0; i<reply->ancount; i++) { + if (reply->answers[i].rr_type == DNS_QTYPE_SRV) { + /* uint16_t can't wrap here. */ + state->num_srvs += 1; + } + } + + state->srvs = talloc_array(state, struct dns_rr_srv, state->num_srvs); + if (tevent_req_nomem(state->srvs, req)) { + return; + } + + idx = 0; + + for (i=0; i<reply->ancount; i++) { + struct dns_res_rec *an = &reply->answers[i]; + struct dns_rr_srv *dst = &state->srvs[idx]; + struct dns_srv_record *src; + + if (an->rr_type != DNS_QTYPE_SRV) { + continue; + } + src = &an->rdata.srv_record; + + *dst = (struct dns_rr_srv) { + .hostname = talloc_move(state->srvs, &src->target), + .priority = src->priority, + .weight = src->weight, + .port = src->port, + }; + idx += 1; + } + + for (i=0; i<reply->arcount; i++) { + struct dns_res_rec *ar = &reply->additional[i]; + struct sockaddr_storage addr; + bool ok; + size_t j; + + ok = dns_res_rec_get_sockaddr(ar, &addr); + if (!ok) { + continue; + } + + for (j=0; j<state->num_srvs; j++) { + struct dns_rr_srv *srv = &state->srvs[j]; + struct sockaddr_storage *tmp; + + if (strcmp(srv->hostname, ar->name) != 0) { + continue; + } + /* uint16_t can't wrap here. */ + tmp = talloc_realloc( + state->srvs, + srv->ss_s, + struct sockaddr_storage, + srv->num_ips+1); + + if (tevent_req_nomem(tmp, req)) { + return; + } + srv->ss_s = tmp; + + srv->ss_s[srv->num_ips] = addr; + srv->num_ips += 1; + } + } + + TYPESAFE_QSORT(state->srvs, state->num_srvs, dnssrvcmp); + + tevent_req_done(req); +} + +NTSTATUS ads_dns_lookup_srv_recv(struct tevent_req *req, + TALLOC_CTX *mem_ctx, + struct dns_rr_srv **srvs, + size_t *num_srvs) +{ + struct ads_dns_lookup_srv_state *state = tevent_req_data( + req, struct ads_dns_lookup_srv_state); + NTSTATUS status; + + if (tevent_req_is_nterror(req, &status)) { + return status; + } + *srvs = talloc_move(mem_ctx, &state->srvs); + *num_srvs = state->num_srvs; + tevent_req_received(req); + return NT_STATUS_OK; +} + +/********************************************************************* + Simple wrapper for a DNS SRV query +*********************************************************************/ + +NTSTATUS ads_dns_lookup_srv(TALLOC_CTX *ctx, + const char *name, + struct dns_rr_srv **dclist, + size_t *numdcs) +{ + struct tevent_context *ev; + struct tevent_req *req; + NTSTATUS status = NT_STATUS_NO_MEMORY; + size_t num_srvs = 0; + + ev = samba_tevent_context_init(ctx); + if (ev == NULL) { + goto fail; + } + req = ads_dns_lookup_srv_send(ev, ev, name); + if (req == NULL) { + goto fail; + } + if (!tevent_req_poll_ntstatus(req, ev, &status)) { + goto fail; + } + status = ads_dns_lookup_srv_recv(req, ctx, dclist, &num_srvs); + if (NT_STATUS_IS_OK(status)) { + *numdcs = num_srvs; + } +fail: + TALLOC_FREE(ev); + return status; +} + +struct ads_dns_lookup_ns_state { + struct dns_rr_ns *nss; + size_t num_nss; +}; + +static void ads_dns_lookup_ns_done(struct tevent_req *subreq); + +struct tevent_req *ads_dns_lookup_ns_send(TALLOC_CTX *mem_ctx, + struct tevent_context *ev, + const char *name) +{ + struct tevent_req *req, *subreq; + struct ads_dns_lookup_ns_state *state; + + req = tevent_req_create(mem_ctx, &state, + struct ads_dns_lookup_ns_state); + if (req == NULL) { + return NULL; + } + + subreq = dns_lookup_send(state, ev, NULL, name, DNS_QCLASS_IN, + DNS_QTYPE_NS); + if (tevent_req_nomem(subreq, req)) { + return tevent_req_post(req, ev); + } + tevent_req_set_callback(subreq, ads_dns_lookup_ns_done, req); + return req; +} + +static void ads_dns_lookup_ns_done(struct tevent_req *subreq) +{ + struct tevent_req *req = tevent_req_callback_data( + subreq, struct tevent_req); + struct ads_dns_lookup_ns_state *state = tevent_req_data( + req, struct ads_dns_lookup_ns_state); + int ret; + struct dns_name_packet *reply; + uint16_t i, idx; + + ret = dns_lookup_recv(subreq, state, &reply); + TALLOC_FREE(subreq); + if (ret != 0) { + tevent_req_nterror(req, map_nt_error_from_unix_common(ret)); + return; + } + + for (i=0; i<reply->ancount; i++) { + if (reply->answers[i].rr_type == DNS_QTYPE_NS) { + state->num_nss += 1; + } + } + + state->nss = talloc_array(state, struct dns_rr_ns, state->num_nss); + if (tevent_req_nomem(state->nss, req)) { + return; + } + + idx = 0; + + for (i=0; i<reply->ancount; i++) { + struct dns_res_rec *an = &reply->answers[i]; + + if (an->rr_type != DNS_QTYPE_NS) { + continue; + } + + state->nss[idx].hostname = talloc_move(state->nss, + &an->rdata.ns_record); + idx += 1; + } + + for (i=0; i<reply->arcount; i++) { + struct dns_res_rec *ar = &reply->additional[i]; + struct sockaddr_storage addr; + bool ok; + size_t j; + + ok = dns_res_rec_get_sockaddr(ar, &addr); + if (!ok) { + continue; + } + + for (j=0; j<state->num_nss; j++) { + struct dns_rr_ns *ns = &state->nss[j]; + + if (strcmp(ns->hostname, ar->name) == 0) { + ns->ss = addr; + } + } + } + + tevent_req_done(req); +} + +NTSTATUS ads_dns_lookup_ns_recv(struct tevent_req *req, + TALLOC_CTX *mem_ctx, + struct dns_rr_ns **nss, + size_t *num_nss) +{ + struct ads_dns_lookup_ns_state *state = tevent_req_data( + req, struct ads_dns_lookup_ns_state); + NTSTATUS status; + + if (tevent_req_is_nterror(req, &status)) { + return status; + } + *nss = talloc_move(mem_ctx, &state->nss); + *num_nss = state->num_nss; + tevent_req_received(req); + return NT_STATUS_OK; +} + +/********************************************************************* + Simple wrapper for a DNS NS query +*********************************************************************/ + +NTSTATUS ads_dns_lookup_ns(TALLOC_CTX *ctx, + const char *dnsdomain, + struct dns_rr_ns **nslist, + size_t *numns) +{ + struct tevent_context *ev; + struct tevent_req *req; + NTSTATUS status = NT_STATUS_NO_MEMORY; + size_t num_ns = 0; + + ev = samba_tevent_context_init(ctx); + if (ev == NULL) { + goto fail; + } + req = ads_dns_lookup_ns_send(ev, ev, dnsdomain); + if (req == NULL) { + goto fail; + } + if (!tevent_req_poll_ntstatus(req, ev, &status)) { + goto fail; + } + status = ads_dns_lookup_ns_recv(req, ctx, nslist, &num_ns); + *numns = num_ns; +fail: + TALLOC_FREE(ev); + return status; +} + +/********************************************************************* + Async A record lookup. +*********************************************************************/ + +struct ads_dns_lookup_a_state { + uint8_t rcode; + size_t num_names; + char **hostnames; + struct samba_sockaddr *addrs; +}; + +static void ads_dns_lookup_a_done(struct tevent_req *subreq); + +struct tevent_req *ads_dns_lookup_a_send(TALLOC_CTX *mem_ctx, + struct tevent_context *ev, + const char *name) +{ + struct tevent_req *req = NULL, *subreq = NULL; + struct ads_dns_lookup_a_state *state = NULL; + + req = tevent_req_create(mem_ctx, &state, + struct ads_dns_lookup_a_state); + if (req == NULL) { + return NULL; + } + + subreq = dns_lookup_send( + state, + ev, + NULL, + name, + DNS_QCLASS_IN, + DNS_QTYPE_A); + + if (tevent_req_nomem(subreq, req)) { + return tevent_req_post(req, ev); + } + tevent_req_set_callback(subreq, ads_dns_lookup_a_done, req); + return req; +} + +static void ads_dns_lookup_a_done(struct tevent_req *subreq) +{ + struct tevent_req *req = tevent_req_callback_data( + subreq, struct tevent_req); + struct ads_dns_lookup_a_state *state = tevent_req_data( + req, struct ads_dns_lookup_a_state); + int ret; + struct dns_name_packet *reply = NULL; + uint16_t i; + + ret = dns_lookup_recv(subreq, state, &reply); + TALLOC_FREE(subreq); + if (ret != 0) { + tevent_req_nterror(req, map_nt_error_from_unix_common(ret)); + return; + } + + state->rcode = (reply->operation & DNS_RCODE); + if (state->rcode != DNS_RCODE_OK) { + /* Don't bother looking for answers. */ + tevent_req_done(req); + return; + } + + /* + * We don't care about CNAME answers here. We're + * just wanting an async name -> IPv4 lookup. + */ + for (i = 0; i < reply->ancount; i++) { + if (reply->answers[i].rr_type == DNS_QTYPE_A) { + state->num_names += 1; + } + } + + state->hostnames = talloc_zero_array(state, + char *, + state->num_names); + if (tevent_req_nomem(state->hostnames, req)) { + return; + } + state->addrs = talloc_zero_array(state, + struct samba_sockaddr, + state->num_names); + if (tevent_req_nomem(state->addrs, req)) { + return; + } + + state->num_names = 0; + + for (i = 0; i < reply->ancount; i++) { + bool ok; + struct sockaddr_storage ss = {0}; + struct dns_res_rec *an = &reply->answers[i]; + + if (an->rr_type != DNS_QTYPE_A) { + continue; + } + if (an->name == NULL) { + /* Can this happen? */ + continue; + } + if (an->rdata.ipv4_record == NULL) { + /* Can this happen? */ + continue; + } + ok = dns_res_rec_get_sockaddr(an, + &ss); + if (!ok) { + continue; + } + if (is_zero_addr(&ss)) { + continue; + } + state->addrs[state->num_names].u.ss = ss; + state->addrs[state->num_names].sa_socklen = + sizeof(struct sockaddr_in); + state->hostnames[state->num_names] = talloc_strdup( + state->hostnames, + an->name); + if (tevent_req_nomem(state->hostnames[state->num_names], req)) { + return; + } + state->num_names += 1; + } + + tevent_req_done(req); +} + +NTSTATUS ads_dns_lookup_a_recv(struct tevent_req *req, + TALLOC_CTX *mem_ctx, + uint8_t *rcode_out, + size_t *num_names_out, + char ***hostnames_out, + struct samba_sockaddr **addrs_out) +{ + struct ads_dns_lookup_a_state *state = tevent_req_data( + req, struct ads_dns_lookup_a_state); + NTSTATUS status; + + if (tevent_req_is_nterror(req, &status)) { + return status; + } + if (rcode_out != NULL) { + /* + * If we got no names, an upper layer may + * want to print a debug message. + */ + *rcode_out = state->rcode; + } + if (hostnames_out != NULL) { + *hostnames_out = talloc_move(mem_ctx, + &state->hostnames); + } + if (addrs_out != NULL) { + *addrs_out = talloc_move(mem_ctx, + &state->addrs); + } + *num_names_out = state->num_names; + tevent_req_received(req); + return NT_STATUS_OK; +} + +/********************************************************************* + Simple wrapper for a DNS A query +*********************************************************************/ + +NTSTATUS ads_dns_lookup_a(TALLOC_CTX *ctx, + const char *name_in, + size_t *num_names_out, + char ***hostnames_out, + struct samba_sockaddr **addrs_out) +{ + struct tevent_context *ev; + struct tevent_req *req; + NTSTATUS status = NT_STATUS_NO_MEMORY; + + ev = samba_tevent_context_init(ctx); + if (ev == NULL) { + goto fail; + } + req = ads_dns_lookup_a_send(ev, ev, name_in); + if (req == NULL) { + goto fail; + } + if (!tevent_req_poll_ntstatus(req, ev, &status)) { + goto fail; + } + /* + * Sychronous doesn't need to care about the rcode or + * a copy of the name_in. + */ + status = ads_dns_lookup_a_recv(req, + ctx, + NULL, + num_names_out, + hostnames_out, + addrs_out); +fail: + TALLOC_FREE(ev); + return status; +} + +#if defined(HAVE_IPV6) +/********************************************************************* + Async AAAA record lookup. +*********************************************************************/ + +struct ads_dns_lookup_aaaa_state { + uint8_t rcode; + size_t num_names; + char **hostnames; + struct samba_sockaddr *addrs; +}; + +static void ads_dns_lookup_aaaa_done(struct tevent_req *subreq); + +struct tevent_req *ads_dns_lookup_aaaa_send(TALLOC_CTX *mem_ctx, + struct tevent_context *ev, + const char *name) +{ + struct tevent_req *req, *subreq = NULL; + struct ads_dns_lookup_aaaa_state *state = NULL; + + req = tevent_req_create(mem_ctx, &state, + struct ads_dns_lookup_aaaa_state); + if (req == NULL) { + return NULL; + } + + subreq = dns_lookup_send( + state, + ev, + NULL, + name, + DNS_QCLASS_IN, + DNS_QTYPE_AAAA); + + if (tevent_req_nomem(subreq, req)) { + return tevent_req_post(req, ev); + } + tevent_req_set_callback(subreq, ads_dns_lookup_aaaa_done, req); + return req; +} + +static void ads_dns_lookup_aaaa_done(struct tevent_req *subreq) +{ + struct tevent_req *req = tevent_req_callback_data( + subreq, struct tevent_req); + struct ads_dns_lookup_aaaa_state *state = tevent_req_data( + req, struct ads_dns_lookup_aaaa_state); + int ret; + struct dns_name_packet *reply = NULL; + uint16_t i; + + ret = dns_lookup_recv(subreq, state, &reply); + TALLOC_FREE(subreq); + if (ret != 0) { + tevent_req_nterror(req, map_nt_error_from_unix_common(ret)); + return; + } + + state->rcode = (reply->operation & DNS_RCODE); + if (state->rcode != DNS_RCODE_OK) { + /* Don't bother looking for answers. */ + tevent_req_done(req); + return; + } + + /* + * We don't care about CNAME answers here. We're + * just wanting an async name -> IPv6 lookup. + */ + for (i = 0; i < reply->ancount; i++) { + if (reply->answers[i].rr_type == DNS_QTYPE_AAAA) { + state->num_names += 1; + } + } + + state->hostnames = talloc_zero_array(state, + char *, + state->num_names); + if (tevent_req_nomem(state->hostnames, req)) { + return; + } + state->addrs = talloc_zero_array(state, + struct samba_sockaddr, + state->num_names); + if (tevent_req_nomem(state->addrs, req)) { + return; + } + + state->num_names = 0; + + for (i = 0; i < reply->ancount; i++) { + bool ok; + struct sockaddr_storage ss = {0}; + struct dns_res_rec *an = &reply->answers[i]; + + if (an->rr_type != DNS_QTYPE_AAAA) { + continue; + } + if (an->name == NULL) { + /* Can this happen? */ + continue; + } + if (an->rdata.ipv6_record == NULL) { + /* Can this happen? */ + continue; + } + ok = dns_res_rec_get_sockaddr(an, + &ss); + if (!ok) { + continue; + } + if (is_zero_addr(&ss)) { + continue; + } + state->addrs[state->num_names].u.ss = ss; + state->addrs[state->num_names].sa_socklen = + sizeof(struct sockaddr_in6); + + state->hostnames[state->num_names] = talloc_strdup( + state->hostnames, + an->name); + if (tevent_req_nomem(state->hostnames[state->num_names], req)) { + return; + } + state->num_names += 1; + } + + tevent_req_done(req); +} + +NTSTATUS ads_dns_lookup_aaaa_recv(struct tevent_req *req, + TALLOC_CTX *mem_ctx, + uint8_t *rcode_out, + size_t *num_names_out, + char ***hostnames_out, + struct samba_sockaddr **addrs_out) +{ + struct ads_dns_lookup_aaaa_state *state = tevent_req_data( + req, struct ads_dns_lookup_aaaa_state); + NTSTATUS status; + + if (tevent_req_is_nterror(req, &status)) { + return status; + } + if (rcode_out != NULL) { + /* + * If we got no names, an upper layer may + * want to print a debug message. + */ + *rcode_out = state->rcode; + } + if (hostnames_out != NULL) { + *hostnames_out = talloc_move(mem_ctx, + &state->hostnames); + } + if (addrs_out != NULL) { + *addrs_out = talloc_move(mem_ctx, + &state->addrs); + } + *num_names_out = state->num_names; + tevent_req_received(req); + return NT_STATUS_OK; +} + +/********************************************************************* + Simple wrapper for a DNS AAAA query +*********************************************************************/ + +NTSTATUS ads_dns_lookup_aaaa(TALLOC_CTX *ctx, + const char *name_in, + size_t *num_names_out, + char ***hostnames_out, + struct samba_sockaddr **addrs_out) +{ + struct tevent_context *ev = NULL; + struct tevent_req *req = NULL; + NTSTATUS status = NT_STATUS_NO_MEMORY; + + ev = samba_tevent_context_init(ctx); + if (ev == NULL) { + goto fail; + } + req = ads_dns_lookup_aaaa_send(ev, ev, name_in); + if (req == NULL) { + goto fail; + } + if (!tevent_req_poll_ntstatus(req, ev, &status)) { + goto fail; + } + /* + * Sychronous doesn't need to care about the rcode or + * a copy of the name_in. + */ + status = ads_dns_lookup_aaaa_recv(req, + ctx, + NULL, + num_names_out, + hostnames_out, + addrs_out); +fail: + TALLOC_FREE(ev); + return status; +} +#endif |