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authorLennart Poettering <lennart@poettering.net>2016-01-20 22:06:26 +0100
committerLennart Poettering <lennart@poettering.net>2016-01-25 15:59:40 +0100
commit839a4a20d8b4f6ebf3a342fd05c821358be5a313 (patch)
tree98a242768ad282c69c7c07327f533792508b93da /src/resolve
parentd07b43a18e2234e8abebc1cd4d93bfd78ab62001 (diff)
resolved: split out RR synthesis logic into its own C file
Also, while we are at it, set the "authenticated" bit for everything we synthesize
Diffstat (limited to 'src/resolve')
-rw-r--r--src/resolve/resolved-dns-query.c386
-rw-r--r--src/resolve/resolved-dns-synthesize.c418
-rw-r--r--src/resolve/resolved-dns-synthesize.h26
3 files changed, 462 insertions, 368 deletions
diff --git a/src/resolve/resolved-dns-query.c b/src/resolve/resolved-dns-query.c
index 47f1924702..2f9dd1c47b 100644
--- a/src/resolve/resolved-dns-query.c
+++ b/src/resolve/resolved-dns-query.c
@@ -24,6 +24,7 @@
#include "hostname-util.h"
#include "local-addresses.h"
#include "resolved-dns-query.h"
+#include "resolved-dns-synthesize.h"
#include "string-util.h"
/* How long to wait for the query in total */
@@ -547,328 +548,15 @@ fail:
return r;
}
-static int SYNTHESIZE_IFINDEX(int ifindex) {
-
- /* When the caller asked for resolving on a specific
- * interface, we synthesize the answer for that
- * interface. However, if nothing specific was claimed and we
- * only return localhost RRs, we synthesize the answer for
- * localhost. */
-
- if (ifindex > 0)
- return ifindex;
-
- return LOOPBACK_IFINDEX;
-}
-
-static int SYNTHESIZE_FAMILY(uint64_t flags) {
-
- /* Picks an address family depending on set flags. This is
- * purely for synthesized answers, where the family we return
- * for the reply should match what was requested in the
- * question, even though we are synthesizing the answer
- * here. */
-
- if (!(flags & SD_RESOLVED_DNS)) {
- if (flags & SD_RESOLVED_LLMNR_IPV4)
- return AF_INET;
- if (flags & SD_RESOLVED_LLMNR_IPV6)
- return AF_INET6;
- }
-
- return AF_UNSPEC;
-}
-
-static DnsProtocol SYNTHESIZE_PROTOCOL(uint64_t flags) {
-
- /* Similar as SYNTHESIZE_FAMILY() but does this for the
- * protocol. If resolving via DNS was requested, we claim it
- * was DNS. Similar, if nothing specific was
- * requested. However, if only resolving via LLMNR was
- * requested we return that. */
-
- if (flags & SD_RESOLVED_DNS)
- return DNS_PROTOCOL_DNS;
- if (flags & SD_RESOLVED_LLMNR)
- return DNS_PROTOCOL_LLMNR;
-
- return DNS_PROTOCOL_DNS;
-}
-
-static int synthesize_localhost_rr(DnsQuery *q, const DnsResourceKey *key, DnsAnswer **answer) {
- int r;
-
- assert(q);
- assert(key);
- assert(answer);
-
- r = dns_answer_reserve(answer, 2);
- if (r < 0)
- return r;
-
- if (IN_SET(key->type, DNS_TYPE_A, DNS_TYPE_ANY)) {
- _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
-
- rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_A, DNS_RESOURCE_KEY_NAME(key));
- if (!rr)
- return -ENOMEM;
-
- rr->a.in_addr.s_addr = htobe32(INADDR_LOOPBACK);
-
- r = dns_answer_add(*answer, rr, SYNTHESIZE_IFINDEX(q->ifindex), DNS_ANSWER_AUTHENTICATED);
- if (r < 0)
- return r;
- }
-
- if (IN_SET(key->type, DNS_TYPE_AAAA, DNS_TYPE_ANY)) {
- _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
-
- rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_AAAA, DNS_RESOURCE_KEY_NAME(key));
- if (!rr)
- return -ENOMEM;
-
- rr->aaaa.in6_addr = in6addr_loopback;
-
- r = dns_answer_add(*answer, rr, SYNTHESIZE_IFINDEX(q->ifindex), DNS_ANSWER_AUTHENTICATED);
- if (r < 0)
- return r;
- }
-
- return 0;
-}
-
-static int answer_add_ptr(DnsAnswer **answer, const char *from, const char *to, int ifindex, DnsAnswerFlags flags) {
- _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
-
- rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_PTR, from);
- if (!rr)
- return -ENOMEM;
-
- rr->ptr.name = strdup(to);
- if (!rr->ptr.name)
- return -ENOMEM;
-
- return dns_answer_add(*answer, rr, ifindex, flags);
-}
-
-static int synthesize_localhost_ptr(DnsQuery *q, const DnsResourceKey *key, DnsAnswer **answer) {
- int r;
-
- assert(q);
- assert(key);
- assert(answer);
-
- if (IN_SET(key->type, DNS_TYPE_PTR, DNS_TYPE_ANY)) {
- r = dns_answer_reserve(answer, 1);
- if (r < 0)
- return r;
-
- r = answer_add_ptr(answer, DNS_RESOURCE_KEY_NAME(key), "localhost", SYNTHESIZE_IFINDEX(q->ifindex), DNS_ANSWER_AUTHENTICATED);
- if (r < 0)
- return r;
- }
-
- return 0;
-}
-
-static int answer_add_addresses_rr(
- DnsAnswer **answer,
- const char *name,
- struct local_address *addresses,
- unsigned n_addresses) {
-
- unsigned j;
- int r;
-
- assert(answer);
- assert(name);
-
- r = dns_answer_reserve(answer, n_addresses);
- if (r < 0)
- return r;
-
- for (j = 0; j < n_addresses; j++) {
- _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
-
- r = dns_resource_record_new_address(&rr, addresses[j].family, &addresses[j].address, name);
- if (r < 0)
- return r;
-
- r = dns_answer_add(*answer, rr, addresses[j].ifindex, DNS_ANSWER_AUTHENTICATED);
- if (r < 0)
- return r;
- }
-
- return 0;
-}
-
-static int answer_add_addresses_ptr(
- DnsAnswer **answer,
- const char *name,
- struct local_address *addresses,
- unsigned n_addresses,
- int af, const union in_addr_union *match) {
-
- unsigned j;
- int r;
-
- assert(answer);
- assert(name);
-
- for (j = 0; j < n_addresses; j++) {
- _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
-
- if (af != AF_UNSPEC) {
-
- if (addresses[j].family != af)
- continue;
-
- if (match && !in_addr_equal(af, match, &addresses[j].address))
- continue;
- }
-
- r = dns_answer_reserve(answer, 1);
- if (r < 0)
- return r;
-
- r = dns_resource_record_new_reverse(&rr, addresses[j].family, &addresses[j].address, name);
- if (r < 0)
- return r;
-
- r = dns_answer_add(*answer, rr, addresses[j].ifindex, DNS_ANSWER_AUTHENTICATED);
- if (r < 0)
- return r;
- }
-
- return 0;
-}
-
-static int synthesize_system_hostname_rr(DnsQuery *q, const DnsResourceKey *key, DnsAnswer **answer) {
- _cleanup_free_ struct local_address *addresses = NULL;
- int n = 0, af;
-
- assert(q);
- assert(key);
- assert(answer);
-
- af = dns_type_to_af(key->type);
- if (af >= 0) {
- n = local_addresses(q->manager->rtnl, q->ifindex, af, &addresses);
- if (n < 0)
- return n;
-
- if (n == 0) {
- struct local_address buffer[2];
-
- /* If we have no local addresses then use ::1
- * and 127.0.0.2 as local ones. */
-
- if (af == AF_INET || af == AF_UNSPEC)
- buffer[n++] = (struct local_address) {
- .family = AF_INET,
- .ifindex = SYNTHESIZE_IFINDEX(q->ifindex),
- .address.in.s_addr = htobe32(0x7F000002),
- };
-
- if (af == AF_INET6 || af == AF_UNSPEC)
- buffer[n++] = (struct local_address) {
- .family = AF_INET6,
- .ifindex = SYNTHESIZE_IFINDEX(q->ifindex),
- .address.in6 = in6addr_loopback,
- };
-
- return answer_add_addresses_rr(answer, DNS_RESOURCE_KEY_NAME(key), buffer, n);
- }
- }
-
- return answer_add_addresses_rr(answer, DNS_RESOURCE_KEY_NAME(key), addresses, n);
-}
-
-static int synthesize_system_hostname_ptr(DnsQuery *q, int af, const union in_addr_union *address, DnsAnswer **answer) {
- _cleanup_free_ struct local_address *addresses = NULL;
- int n, r;
-
- assert(q);
- assert(address);
- assert(answer);
-
- if (af == AF_INET && address->in.s_addr == htobe32(0x7F000002)) {
-
- /* Always map the IPv4 address 127.0.0.2 to the local
- * hostname, in addition to "localhost": */
-
- r = dns_answer_reserve(answer, 3);
- if (r < 0)
- return r;
-
- r = answer_add_ptr(answer, "2.0.0.127.in-addr.arpa", q->manager->llmnr_hostname, SYNTHESIZE_IFINDEX(q->ifindex), DNS_ANSWER_AUTHENTICATED);
- if (r < 0)
- return r;
-
- r = answer_add_ptr(answer, "2.0.0.127.in-addr.arpa", q->manager->mdns_hostname, SYNTHESIZE_IFINDEX(q->ifindex), DNS_ANSWER_AUTHENTICATED);
- if (r < 0)
- return r;
-
- r = answer_add_ptr(answer, "2.0.0.127.in-addr.arpa", "localhost", SYNTHESIZE_IFINDEX(q->ifindex), DNS_ANSWER_AUTHENTICATED);
- if (r < 0)
- return r;
-
- return 0;
- }
-
- n = local_addresses(q->manager->rtnl, q->ifindex, af, &addresses);
- if (n < 0)
- return n;
-
- r = answer_add_addresses_ptr(answer, q->manager->llmnr_hostname, addresses, n, af, address);
- if (r < 0)
- return r;
-
- return answer_add_addresses_ptr(answer, q->manager->mdns_hostname, addresses, n, af, address);
-}
-
-static int synthesize_gateway_rr(DnsQuery *q, const DnsResourceKey *key, DnsAnswer **answer) {
- _cleanup_free_ struct local_address *addresses = NULL;
- int n = 0, af;
-
- assert(q);
- assert(key);
- assert(answer);
-
- af = dns_type_to_af(key->type);
- if (af >= 0) {
- n = local_gateways(q->manager->rtnl, q->ifindex, af, &addresses);
- if (n < 0)
- return n;
- }
-
- return answer_add_addresses_rr(answer, DNS_RESOURCE_KEY_NAME(key), addresses, n);
-}
-
-static int synthesize_gateway_ptr(DnsQuery *q, int af, const union in_addr_union *address, DnsAnswer **answer) {
- _cleanup_free_ struct local_address *addresses = NULL;
- int n;
-
- assert(q);
- assert(address);
- assert(answer);
-
- n = local_gateways(q->manager->rtnl, q->ifindex, af, &addresses);
- if (n < 0)
- return n;
-
- return answer_add_addresses_ptr(answer, "gateway", addresses, n, af, address);
-}
-
static int dns_query_synthesize_reply(DnsQuery *q, DnsTransactionState *state) {
_cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL;
- DnsResourceKey *key;
- int r;
+ DnsProtocol protocol;
+ int family, r;
assert(q);
assert(state);
- /* Tries to synthesize localhost RR replies where appropriate */
+ /* Tries to synthesize localhost RR replies (and others) where appropriate */
if (!IN_SET(*state,
DNS_TRANSACTION_RCODE_FAILURE,
@@ -878,64 +566,26 @@ static int dns_query_synthesize_reply(DnsQuery *q, DnsTransactionState *state) {
DNS_TRANSACTION_NETWORK_DOWN))
return 0;
- DNS_QUESTION_FOREACH(key, q->question_utf8) {
- union in_addr_union address;
- const char *name;
- int af;
-
- if (key->class != DNS_CLASS_IN &&
- key->class != DNS_CLASS_ANY)
- continue;
-
- name = DNS_RESOURCE_KEY_NAME(key);
+ r = dns_synthesize_answer(
+ q->manager,
+ q->question_utf8,
+ q->ifindex,
+ q->flags,
+ &answer,
+ &protocol,
+ &family);
- if (is_localhost(name)) {
-
- r = synthesize_localhost_rr(q, key, &answer);
- if (r < 0)
- return log_error_errno(r, "Failed to synthesize localhost RRs: %m");
-
- } else if (manager_is_own_hostname(q->manager, name)) {
-
- r = synthesize_system_hostname_rr(q, key, &answer);
- if (r < 0)
- return log_error_errno(r, "Failed to synthesize system hostname RRs: %m");
-
- } else if (is_gateway_hostname(name)) {
-
- r = synthesize_gateway_rr(q, key, &answer);
- if (r < 0)
- return log_error_errno(r, "Failed to synthesize gateway RRs: %m");
-
- } else if ((dns_name_endswith(name, "127.in-addr.arpa") > 0 && dns_name_equal(name, "2.0.0.127.in-addr.arpa") == 0) ||
- dns_name_equal(name, "1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa") > 0) {
-
- r = synthesize_localhost_ptr(q, key, &answer);
- if (r < 0)
- return log_error_errno(r, "Failed to synthesize localhost PTR RRs: %m");
-
- } else if (dns_name_address(name, &af, &address) > 0) {
-
- r = synthesize_system_hostname_ptr(q, af, &address, &answer);
- if (r < 0)
- return log_error_errno(r, "Failed to synthesize system hostname PTR RR: %m");
-
- r = synthesize_gateway_ptr(q, af, &address, &answer);
- if (r < 0)
- return log_error_errno(r, "Failed to synthesize gateway hostname PTR RR: %m");
- }
- }
+ if (r <= 0)
+ return r;
- if (!answer)
- return 0;
+ dns_query_reset_answer(q);
- dns_answer_unref(q->answer);
q->answer = answer;
answer = NULL;
-
q->answer_rcode = DNS_RCODE_SUCCESS;
- q->answer_protocol = SYNTHESIZE_PROTOCOL(q->flags);
- q->answer_family = SYNTHESIZE_FAMILY(q->flags);
+ q->answer_protocol = protocol;
+ q->answer_family = family;
+ q->answer_authenticated = true;
*state = DNS_TRANSACTION_SUCCESS;
diff --git a/src/resolve/resolved-dns-synthesize.c b/src/resolve/resolved-dns-synthesize.c
new file mode 100644
index 0000000000..e12bb6e828
--- /dev/null
+++ b/src/resolve/resolved-dns-synthesize.c
@@ -0,0 +1,418 @@
+/***
+ This file is part of systemd.
+
+ Copyright 2014 Lennart Poettering
+
+ systemd is free software; you can redistribute it and/or modify it
+ under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 2.1 of the License, or
+ (at your option) any later version.
+
+ systemd 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
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include "alloc-util.h"
+#include "hostname-util.h"
+#include "local-addresses.h"
+#include "resolved-dns-synthesize.h"
+
+static int SYNTHESIZE_IFINDEX(int ifindex) {
+
+ /* When the caller asked for resolving on a specific
+ * interface, we synthesize the answer for that
+ * interface. However, if nothing specific was claimed and we
+ * only return localhost RRs, we synthesize the answer for
+ * localhost. */
+
+ if (ifindex > 0)
+ return ifindex;
+
+ return LOOPBACK_IFINDEX;
+}
+
+static int SYNTHESIZE_FAMILY(uint64_t flags) {
+
+ /* Picks an address family depending on set flags. This is
+ * purely for synthesized answers, where the family we return
+ * for the reply should match what was requested in the
+ * question, even though we are synthesizing the answer
+ * here. */
+
+ if (!(flags & SD_RESOLVED_DNS)) {
+ if (flags & (SD_RESOLVED_LLMNR_IPV4|SD_RESOLVED_MDNS_IPV4))
+ return AF_INET;
+ if (flags & (SD_RESOLVED_LLMNR_IPV6|SD_RESOLVED_MDNS_IPV6))
+ return AF_INET6;
+ }
+
+ return AF_UNSPEC;
+}
+
+static DnsProtocol SYNTHESIZE_PROTOCOL(uint64_t flags) {
+
+ /* Similar as SYNTHESIZE_FAMILY() but does this for the
+ * protocol. If resolving via DNS was requested, we claim it
+ * was DNS. Similar, if nothing specific was
+ * requested. However, if only resolving via LLMNR was
+ * requested we return that. */
+
+ if (flags & SD_RESOLVED_DNS)
+ return DNS_PROTOCOL_DNS;
+ if (flags & SD_RESOLVED_LLMNR)
+ return DNS_PROTOCOL_LLMNR;
+ if (flags & SD_RESOLVED_MDNS)
+ return DNS_PROTOCOL_MDNS;
+
+ return DNS_PROTOCOL_DNS;
+}
+
+static int synthesize_localhost_rr(Manager *m, const DnsResourceKey *key, int ifindex, DnsAnswer **answer) {
+ int r;
+
+ assert(m);
+ assert(key);
+ assert(answer);
+
+ r = dns_answer_reserve(answer, 2);
+ if (r < 0)
+ return r;
+
+ if (IN_SET(key->type, DNS_TYPE_A, DNS_TYPE_ANY)) {
+ _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
+
+ rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_A, DNS_RESOURCE_KEY_NAME(key));
+ if (!rr)
+ return -ENOMEM;
+
+ rr->a.in_addr.s_addr = htobe32(INADDR_LOOPBACK);
+
+ r = dns_answer_add(*answer, rr, SYNTHESIZE_IFINDEX(ifindex), DNS_ANSWER_AUTHENTICATED);
+ if (r < 0)
+ return r;
+ }
+
+ if (IN_SET(key->type, DNS_TYPE_AAAA, DNS_TYPE_ANY)) {
+ _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
+
+ rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_AAAA, DNS_RESOURCE_KEY_NAME(key));
+ if (!rr)
+ return -ENOMEM;
+
+ rr->aaaa.in6_addr = in6addr_loopback;
+
+ r = dns_answer_add(*answer, rr, SYNTHESIZE_IFINDEX(ifindex), DNS_ANSWER_AUTHENTICATED);
+ if (r < 0)
+ return r;
+ }
+
+ return 0;
+}
+
+static int answer_add_ptr(DnsAnswer **answer, const char *from, const char *to, int ifindex, DnsAnswerFlags flags) {
+ _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
+
+ rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_PTR, from);
+ if (!rr)
+ return -ENOMEM;
+
+ rr->ptr.name = strdup(to);
+ if (!rr->ptr.name)
+ return -ENOMEM;
+
+ return dns_answer_add(*answer, rr, ifindex, flags);
+}
+
+static int synthesize_localhost_ptr(Manager *m, const DnsResourceKey *key, int ifindex, DnsAnswer **answer) {
+ int r;
+
+ assert(m);
+ assert(key);
+ assert(answer);
+
+ if (IN_SET(key->type, DNS_TYPE_PTR, DNS_TYPE_ANY)) {
+ r = dns_answer_reserve(answer, 1);
+ if (r < 0)
+ return r;
+
+ r = answer_add_ptr(answer, DNS_RESOURCE_KEY_NAME(key), "localhost", SYNTHESIZE_IFINDEX(ifindex), DNS_ANSWER_AUTHENTICATED);
+ if (r < 0)
+ return r;
+ }
+
+ return 0;
+}
+
+static int answer_add_addresses_rr(
+ DnsAnswer **answer,
+ const char *name,
+ struct local_address *addresses,
+ unsigned n_addresses) {
+
+ unsigned j;
+ int r;
+
+ assert(answer);
+ assert(name);
+
+ r = dns_answer_reserve(answer, n_addresses);
+ if (r < 0)
+ return r;
+
+ for (j = 0; j < n_addresses; j++) {
+ _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
+
+ r = dns_resource_record_new_address(&rr, addresses[j].family, &addresses[j].address, name);
+ if (r < 0)
+ return r;
+
+ r = dns_answer_add(*answer, rr, addresses[j].ifindex, DNS_ANSWER_AUTHENTICATED);
+ if (r < 0)
+ return r;
+ }
+
+ return 0;
+}
+
+static int answer_add_addresses_ptr(
+ DnsAnswer **answer,
+ const char *name,
+ struct local_address *addresses,
+ unsigned n_addresses,
+ int af, const union in_addr_union *match) {
+
+ unsigned j;
+ int r;
+
+ assert(answer);
+ assert(name);
+
+ for (j = 0; j < n_addresses; j++) {
+ _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
+
+ if (af != AF_UNSPEC) {
+
+ if (addresses[j].family != af)
+ continue;
+
+ if (match && !in_addr_equal(af, match, &addresses[j].address))
+ continue;
+ }
+
+ r = dns_answer_reserve(answer, 1);
+ if (r < 0)
+ return r;
+
+ r = dns_resource_record_new_reverse(&rr, addresses[j].family, &addresses[j].address, name);
+ if (r < 0)
+ return r;
+
+ r = dns_answer_add(*answer, rr, addresses[j].ifindex, DNS_ANSWER_AUTHENTICATED);
+ if (r < 0)
+ return r;
+ }
+
+ return 0;
+}
+
+static int synthesize_system_hostname_rr(Manager *m, const DnsResourceKey *key, int ifindex, DnsAnswer **answer) {
+ _cleanup_free_ struct local_address *addresses = NULL;
+ int n = 0, af;
+
+ assert(m);
+ assert(key);
+ assert(answer);
+
+ af = dns_type_to_af(key->type);
+ if (af >= 0) {
+ n = local_addresses(m->rtnl, ifindex, af, &addresses);
+ if (n < 0)
+ return n;
+
+ if (n == 0) {
+ struct local_address buffer[2];
+
+ /* If we have no local addresses then use ::1
+ * and 127.0.0.2 as local ones. */
+
+ if (af == AF_INET || af == AF_UNSPEC)
+ buffer[n++] = (struct local_address) {
+ .family = AF_INET,
+ .ifindex = SYNTHESIZE_IFINDEX(ifindex),
+ .address.in.s_addr = htobe32(0x7F000002),
+ };
+
+ if (af == AF_INET6 || af == AF_UNSPEC)
+ buffer[n++] = (struct local_address) {
+ .family = AF_INET6,
+ .ifindex = SYNTHESIZE_IFINDEX(ifindex),
+ .address.in6 = in6addr_loopback,
+ };
+
+ return answer_add_addresses_rr(answer, DNS_RESOURCE_KEY_NAME(key), buffer, n);
+ }
+ }
+
+ return answer_add_addresses_rr(answer, DNS_RESOURCE_KEY_NAME(key), addresses, n);
+}
+
+static int synthesize_system_hostname_ptr(Manager *m, int af, const union in_addr_union *address, int ifindex, DnsAnswer **answer) {
+ _cleanup_free_ struct local_address *addresses = NULL;
+ int n, r;
+
+ assert(m);
+ assert(address);
+ assert(answer);
+
+ if (af == AF_INET && address->in.s_addr == htobe32(0x7F000002)) {
+
+ /* Always map the IPv4 address 127.0.0.2 to the local
+ * hostname, in addition to "localhost": */
+
+ r = dns_answer_reserve(answer, 3);
+ if (r < 0)
+ return r;
+
+ r = answer_add_ptr(answer, "2.0.0.127.in-addr.arpa", m->llmnr_hostname, SYNTHESIZE_IFINDEX(ifindex), DNS_ANSWER_AUTHENTICATED);
+ if (r < 0)
+ return r;
+
+ r = answer_add_ptr(answer, "2.0.0.127.in-addr.arpa", m->mdns_hostname, SYNTHESIZE_IFINDEX(ifindex), DNS_ANSWER_AUTHENTICATED);
+ if (r < 0)
+ return r;
+
+ r = answer_add_ptr(answer, "2.0.0.127.in-addr.arpa", "localhost", SYNTHESIZE_IFINDEX(ifindex), DNS_ANSWER_AUTHENTICATED);
+ if (r < 0)
+ return r;
+
+ return 0;
+ }
+
+ n = local_addresses(m->rtnl, ifindex, af, &addresses);
+ if (n < 0)
+ return n;
+
+ r = answer_add_addresses_ptr(answer, m->llmnr_hostname, addresses, n, af, address);
+ if (r < 0)
+ return r;
+
+ return answer_add_addresses_ptr(answer, m->mdns_hostname, addresses, n, af, address);
+}
+
+static int synthesize_gateway_rr(Manager *m, const DnsResourceKey *key, int ifindex, DnsAnswer **answer) {
+ _cleanup_free_ struct local_address *addresses = NULL;
+ int n = 0, af;
+
+ assert(m);
+ assert(key);
+ assert(answer);
+
+ af = dns_type_to_af(key->type);
+ if (af >= 0) {
+ n = local_gateways(m->rtnl, ifindex, af, &addresses);
+ if (n < 0)
+ return n;
+ }
+
+ return answer_add_addresses_rr(answer, DNS_RESOURCE_KEY_NAME(key), addresses, n);
+}
+
+static int synthesize_gateway_ptr(Manager *m, int af, const union in_addr_union *address, int ifindex, DnsAnswer **answer) {
+ _cleanup_free_ struct local_address *addresses = NULL;
+ int n;
+
+ assert(m);
+ assert(address);
+ assert(answer);
+
+ n = local_gateways(m->rtnl, ifindex, af, &addresses);
+ if (n < 0)
+ return n;
+
+ return answer_add_addresses_ptr(answer, "gateway", addresses, n, af, address);
+}
+
+int dns_synthesize_answer(
+ Manager *m,
+ DnsQuestion *q,
+ int ifindex,
+ uint64_t flags,
+ DnsAnswer **ret,
+ DnsProtocol *ret_protocol,
+ int *ret_family) {
+
+ _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL;
+ DnsResourceKey *key;
+ int r;
+
+ assert(m);
+ assert(q);
+
+ DNS_QUESTION_FOREACH(key, q) {
+ union in_addr_union address;
+ const char *name;
+ int af;
+
+ if (key->class != DNS_CLASS_IN &&
+ key->class != DNS_CLASS_ANY)
+ continue;
+
+ name = DNS_RESOURCE_KEY_NAME(key);
+
+ if (is_localhost(name)) {
+
+ r = synthesize_localhost_rr(m, key, ifindex, &answer);
+ if (r < 0)
+ return log_error_errno(r, "Failed to synthesize localhost RRs: %m");
+
+ } else if (manager_is_own_hostname(m, name)) {
+
+ r = synthesize_system_hostname_rr(m, key, ifindex, &answer);
+ if (r < 0)
+ return log_error_errno(r, "Failed to synthesize system hostname RRs: %m");
+
+ } else if (is_gateway_hostname(name)) {
+
+ r = synthesize_gateway_rr(m, key, ifindex, &answer);
+ if (r < 0)
+ return log_error_errno(r, "Failed to synthesize gateway RRs: %m");
+
+ } else if ((dns_name_endswith(name, "127.in-addr.arpa") > 0 && dns_name_equal(name, "2.0.0.127.in-addr.arpa") == 0) ||
+ dns_name_equal(name, "1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa") > 0) {
+
+ r = synthesize_localhost_ptr(m, key, ifindex, &answer);
+ if (r < 0)
+ return log_error_errno(r, "Failed to synthesize localhost PTR RRs: %m");
+
+ } else if (dns_name_address(name, &af, &address) > 0) {
+
+ r = synthesize_system_hostname_ptr(m, af, &address, ifindex, &answer);
+ if (r < 0)
+ return log_error_errno(r, "Failed to synthesize system hostname PTR RR: %m");
+
+ r = synthesize_gateway_ptr(m, af, &address, ifindex, &answer);
+ if (r < 0)
+ return log_error_errno(r, "Failed to synthesize gateway hostname PTR RR: %m");
+ }
+ }
+
+ r = dns_answer_size(answer) > 0;
+
+ if (ret) {
+ *ret = answer;
+ answer = NULL;
+ }
+
+ if (ret_protocol)
+ *ret_protocol = SYNTHESIZE_PROTOCOL(flags);
+
+ if (ret_family)
+ *ret_family = SYNTHESIZE_FAMILY(flags);
+
+ return r;
+}
diff --git a/src/resolve/resolved-dns-synthesize.h b/src/resolve/resolved-dns-synthesize.h
new file mode 100644
index 0000000000..e43d96cb2c
--- /dev/null
+++ b/src/resolve/resolved-dns-synthesize.h
@@ -0,0 +1,26 @@
+#pragma once
+
+/***
+ This file is part of systemd.
+
+ Copyright 2016 Lennart Poettering
+
+ systemd is free software; you can redistribute it and/or modify it
+ under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 2.1 of the License, or
+ (at your option) any later version.
+
+ systemd 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
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include "resolved-dns-answer.h"
+#include "resolved-dns-question.h"
+#include "resolved-manager.h"
+
+int dns_synthesize_answer(Manager *m, DnsQuestion *q, int ifindex, uint64_t flags, DnsAnswer **ret, DnsProtocol *ret_protocol, int *ret_family);