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Merge pull request #955 from poettering/resolved-localhost-xyz

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resolved: enable synthesizing of A, AAAA and PTR records for "localhost"
This commit is contained in:
Tom Gundersen 2015-08-16 20:46:11 +02:00
commit 0125ed22e3
2 changed files with 169 additions and 5 deletions
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166
src/resolve/resolved-dns-query.c
View File

@ -19,6 +19,8 @@
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include "hostname-util.h"
#include "dns-domain.h"
#include "resolved-dns-query.h"
@ -212,6 +214,156 @@ static int dns_query_add_transaction_split(DnsQuery *q, DnsScope *s) {
return 0;
}
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, 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 void dns_query_synthesize_reply(DnsQuery *q, DnsTransactionState *state) {
_cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL;
unsigned i;
int r;
assert(q);
assert(state);
/* Tries to synthesize localhost RR replies where appropriate */
if (!IN_SET(*state,
DNS_TRANSACTION_FAILURE,
DNS_TRANSACTION_NO_SERVERS,
DNS_TRANSACTION_TIMEOUT,
DNS_TRANSACTION_ATTEMPTS_MAX_REACHED))
return;
for (i = 0; i < q->question->n_keys; i++) {
_cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
const char *name;
if (q->question->keys[i]->class != DNS_CLASS_IN &&
q->question->keys[i]->class != DNS_CLASS_ANY)
continue;
name = DNS_RESOURCE_KEY_NAME(q->question->keys[i]);
if (is_localhost(name)) {
switch (q->question->keys[i]->type) {
case DNS_TYPE_A:
case DNS_TYPE_ANY:
rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_A, name);
if (!rr) {
log_oom();
return;
}
rr->a.in_addr.s_addr = htobe32(INADDR_LOOPBACK);
break;
case DNS_TYPE_AAAA:
rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_AAAA, name);
if (!rr) {
log_oom();
return;
}
rr->aaaa.in6_addr = in6addr_loopback;
break;
}
} else if (IN_SET(q->question->keys[i]->type, DNS_TYPE_PTR, DNS_TYPE_ANY) &&
(dns_name_endswith(name, "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)) {
rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_PTR, name);
if (!rr) {
log_oom();
return;
}
rr->ptr.name = strdup("localhost");
if (!rr->ptr.name) {
log_oom();
return;
}
}
if (!rr)
continue;
if (!answer) {
answer = dns_answer_new(q->question->n_keys);
if (!answer) {
log_oom();
return;
}
}
r = dns_answer_add(answer, rr);
if (r < 0) {
log_error_errno(r, "Failed to add synthetic RR to answer: %m");
return;
}
}
if (!answer)
return;
dns_answer_unref(q->answer);
q->answer = answer;
answer = NULL;
q->answer_ifindex = SYNTHESIZE_IFINDEX(q->ifindex);
q->answer_family = SYNTHESIZE_FAMILY(q->flags);
q->answer_protocol = SYNTHESIZE_PROTOCOL(q->flags);
q->answer_rcode = DNS_RCODE_SUCCESS;
*state = DNS_TRANSACTION_SUCCESS;
}
int dns_query_go(DnsQuery *q) {
DnsScopeMatch found = DNS_SCOPE_NO;
DnsScope *s, *first = NULL;
@ -253,8 +405,17 @@ int dns_query_go(DnsQuery *q) {
}
}
if (found == DNS_SCOPE_NO)
if (found == DNS_SCOPE_NO) {
DnsTransactionState state = DNS_TRANSACTION_NO_SERVERS;
dns_query_synthesize_reply(q, &state);
if (state != DNS_TRANSACTION_NO_SERVERS) {
dns_query_complete(q, state);
return 1;
}
return -ESRCH;
}
r = dns_query_add_transaction_split(q, first);
if (r < 0)
@ -428,6 +589,9 @@ void dns_query_ready(DnsQuery *q) {
q->answer_family = scope ? scope->family : AF_UNSPEC;
}
/* Try to synthesize a reply if we couldn't resolve something. */
dns_query_synthesize_reply(q, &state);
dns_query_complete(q, state);
}

8
src/resolve/resolved-dns-scope.c
View File

@ -325,10 +325,6 @@ DnsScopeMatch dns_scope_good_domain(DnsScope *s, int ifindex, uint64_t flags, co
if ((SD_RESOLVED_FLAGS_MAKE(s->protocol, s->family) & flags) == 0)
return DNS_SCOPE_NO;
STRV_FOREACH(i, s->domains)
if (dns_name_endswith(domain, *i) > 0)
return DNS_SCOPE_YES;
if (dns_name_root(domain) != 0)
return DNS_SCOPE_NO;
@ -340,6 +336,10 @@ DnsScopeMatch dns_scope_good_domain(DnsScope *s, int ifindex, uint64_t flags, co
dns_name_equal(domain, "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)
return DNS_SCOPE_NO;
STRV_FOREACH(i, s->domains)
if (dns_name_endswith(domain, *i) > 0)
return DNS_SCOPE_YES;
if (s->protocol == DNS_PROTOCOL_DNS) {
if (dns_name_endswith(domain, "254.169.in-addr.arpa") == 0 &&
dns_name_endswith(domain, "0.8.e.f.ip6.arpa") == 0 &&