static int dns_stub_make_reply_packet(
DnsPacket **p,
size_t max_size,
DnsQuestion *q,
DnsAnswer *answer,
bool *ret_truncated) {
bool truncated = false;
DnsResourceRecord *rr;
unsigned c = 0;
int r;
assert(p);
/* Note that we don't bother with any additional RRs, as this is stub is for local lookups only, and hence
* roundtrips aren't expensive. */
if (!*p) {
r = dns_packet_new(p, DNS_PROTOCOL_DNS, 0, max_size);
if (r < 0)
return r;
r = dns_packet_append_question(*p, q);
if (r < 0)
return r;
DNS_PACKET_HEADER(*p)->qdcount = htobe16(dns_question_size(q));
}
DNS_ANSWER_FOREACH(rr, answer) {
r = dns_question_matches_rr(q, rr, NULL);
if (r < 0)
return r;
if (r > 0)
goto add;
r = dns_question_matches_cname_or_dname(q, rr, NULL);
if (r < 0)
return r;
if (r > 0)
goto add;
continue;
add:
r = dns_packet_append_rr(*p, rr, 0, NULL, NULL);
if (r == -EMSGSIZE) {
truncated = true;
break;
}
if (r < 0)
return r;
c++;
}
static int dns_stub_make_reply_packet(
uint16_t id,
int rcode,
DnsQuestion *q,
DnsAnswer *answer,
bool add_opt, /* add an OPT RR to this packet */
bool edns0_do, /* set the EDNS0 DNSSEC OK bit */
bool ad, /* set the DNSSEC authenticated data bit */
DnsPacket **ret) {
_cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
DnsResourceRecord *rr;
unsigned c = 0;
int r;
/* Note that we don't bother with any additional RRs, as this is stub is for local lookups only, and hence
* roundtrips aren't expensive. */
r = dns_packet_new(&p, DNS_PROTOCOL_DNS, 0);
if (r < 0)
return r;
/* If the client didn't do EDNS, clamp the rcode to 4 bit */
if (!add_opt && rcode > 0xF)
rcode = DNS_RCODE_SERVFAIL;
DNS_PACKET_HEADER(p)->id = id;
DNS_PACKET_HEADER(p)->flags = htobe16(DNS_PACKET_MAKE_FLAGS(
1 /* qr */,
0 /* opcode */,
0 /* aa */,
0 /* tc */,
1 /* rd */,
1 /* ra */,
ad /* ad */,
0 /* cd */,
rcode));
r = dns_packet_append_question(p, q);
if (r < 0)
return r;
DNS_PACKET_HEADER(p)->qdcount = htobe16(dns_question_size(q));
DNS_ANSWER_FOREACH(rr, answer) {
r = dns_question_matches_rr(q, rr, NULL);
if (r < 0)
return r;
if (r > 0)
goto add;
r = dns_question_matches_cname_or_dname(q, rr, NULL);
if (r < 0)
return r;
if (r > 0)
goto add;
continue;
add:
r = dns_packet_append_rr(p, rr, NULL, NULL);
if (r < 0)
return r;
c++;
}
static void bus_method_resolve_record_complete(DnsQuery *q) {
_cleanup_bus_message_unref_ sd_bus_message *reply = NULL;
_cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL;
unsigned added = 0, i;
int r;
assert(q);
if (q->state != DNS_TRANSACTION_SUCCESS) {
r = reply_query_state(q);
goto finish;
}
r = sd_bus_message_new_method_return(q->request, &reply);
if (r < 0)
goto finish;
r = sd_bus_message_append(reply, "i", q->answer_ifindex);
if (r < 0)
goto finish;
r = sd_bus_message_open_container(reply, 'a', "(qqay)");
if (r < 0)
goto finish;
if (q->answer) {
answer = dns_answer_ref(q->answer);
for (i = 0; i < answer->n_rrs; i++) {
_cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
size_t start;
r = dns_question_matches_rr(q->question, answer->rrs[i]);
if (r < 0)
goto finish;
if (r == 0)
continue;
r = dns_packet_new(&p, DNS_PROTOCOL_DNS, 0);
if (r < 0)
goto finish;
r = dns_packet_append_rr(p, answer->rrs[i], &start);
if (r < 0)
goto finish;
r = sd_bus_message_open_container(reply, 'r', "qqay");
if (r < 0)
goto finish;
r = sd_bus_message_append(reply, "qq", answer->rrs[i]->key->class, answer->rrs[i]->key->type);
if (r < 0)
goto finish;
r = sd_bus_message_append_array(reply, 'y', DNS_PACKET_DATA(p) + start, p->size - start);
if (r < 0)
goto finish;
r = sd_bus_message_close_container(reply);
if (r < 0)
goto finish;
added ++;
}
}
static void bus_method_resolve_address_complete(DnsQuery *q) {
_cleanup_bus_message_unref_ sd_bus_message *reply = NULL;
_cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL;
unsigned added = 0, i;
int r;
assert(q);
if (q->state != DNS_TRANSACTION_SUCCESS) {
r = reply_query_state(q);
goto finish;
}
r = sd_bus_message_new_method_return(q->request, &reply);
if (r < 0)
goto finish;
r = sd_bus_message_append(reply, "i", q->answer_ifindex);
if (r < 0)
goto finish;
r = sd_bus_message_open_container(reply, 'a', "s");
if (r < 0)
goto finish;
if (q->answer) {
answer = dns_answer_ref(q->answer);
for (i = 0; i < answer->n_rrs; i++) {
r = dns_question_matches_rr(q->question, answer->rrs[i]);
if (r < 0)
goto finish;
if (r == 0)
continue;
r = sd_bus_message_append(reply, "s", answer->rrs[i]->ptr.name);
if (r < 0)
goto finish;
added ++;
}
}
if (added <= 0) {
_cleanup_free_ char *ip = NULL;
in_addr_to_string(q->request_family, &q->request_address, &ip);
r = sd_bus_reply_method_errorf(q->request, BUS_ERROR_NO_SUCH_RR, "Address '%s' does not have any RR of requested type", ip);
goto finish;
}
r = sd_bus_message_close_container(reply);
if (r < 0)
goto finish;
r = sd_bus_message_append(reply, "t", SD_RESOLVED_FLAGS_MAKE(q->answer_protocol, q->answer_family));
if (r < 0)
goto finish;
r = sd_bus_send(q->manager->bus, reply, NULL);
finish:
if (r < 0) {
log_error_errno(r, "Failed to send address reply: %m");
sd_bus_reply_method_errno(q->request, -r, NULL);
}
dns_query_free(q);
}
static void bus_method_resolve_hostname_complete(DnsQuery *q) {
_cleanup_(dns_resource_record_unrefp) DnsResourceRecord *cname = NULL, *canonical = NULL;
_cleanup_bus_message_unref_ sd_bus_message *reply = NULL;
_cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL;
unsigned added = 0, i;
int r;
assert(q);
if (q->state != DNS_TRANSACTION_SUCCESS) {
r = reply_query_state(q);
goto finish;
}
r = sd_bus_message_new_method_return(q->request, &reply);
if (r < 0)
goto finish;
r = sd_bus_message_append(reply, "i", q->answer_ifindex);
if (r < 0)
goto finish;
r = sd_bus_message_open_container(reply, 'a', "(iay)");
if (r < 0)
goto finish;
if (q->answer) {
answer = dns_answer_ref(q->answer);
for (i = 0; i < answer->n_rrs; i++) {
r = dns_question_matches_rr(q->question, answer->rrs[i]);
if (r < 0)
goto finish;
if (r == 0) {
/* Hmm, if this is not an address record,
maybe it's a cname? If so, remember this */
r = dns_question_matches_cname(q->question, answer->rrs[i]);
if (r < 0)
goto finish;
if (r > 0)
cname = dns_resource_record_ref(answer->rrs[i]);
continue;
}
r = append_address(reply, answer->rrs[i]);
if (r < 0)
goto finish;
if (!canonical)
canonical = dns_resource_record_ref(answer->rrs[i]);
added ++;
}
}
if (added <= 0) {
if (!cname) {
r = sd_bus_reply_method_errorf(q->request, BUS_ERROR_NO_SUCH_RR, "'%s' does not have any RR of requested type", q->request_hostname);
goto finish;
}
/* This has a cname? Then update the query with the
* new cname. */
r = dns_query_cname_redirect(q, cname->cname.name);
if (r < 0) {
if (r == -ELOOP)
r = sd_bus_reply_method_errorf(q->request, BUS_ERROR_CNAME_LOOP, "CNAME loop on '%s'", q->request_hostname);
else
r = sd_bus_reply_method_errno(q->request, -r, NULL);
goto finish;
}
/* Before we restart the query, let's see if any of
* the RRs we already got already answers our query */
for (i = 0; i < answer->n_rrs; i++) {
r = dns_question_matches_rr(q->question, answer->rrs[i]);
if (r < 0)
goto finish;
if (r == 0)
continue;
r = append_address(reply, answer->rrs[i]);
if (r < 0)
goto finish;
if (!canonical)
canonical = dns_resource_record_ref(answer->rrs[i]);
added++;
}
/* If we didn't find anything, then let's restart the
* query, this time with the cname */
if (added <= 0) {
r = dns_query_go(q);
if (r == -ESRCH) {
r = sd_bus_reply_method_errorf(q->request, BUS_ERROR_NO_NAME_SERVERS, "No appropriate name servers or networks for name found");
goto finish;
}
if (r < 0) {
r = sd_bus_reply_method_errno(q->request, -r, NULL);
goto finish;
}
return;
}
}
r = sd_bus_message_close_container(reply);
if (r < 0)
goto finish;
/* Return the precise spelling and uppercasing reported by the server */
assert(canonical);
r = sd_bus_message_append(reply, "st", DNS_RESOURCE_KEY_NAME(canonical->key), SD_RESOLVED_FLAGS_MAKE(q->answer_protocol, q->answer_family));
if (r < 0)
goto finish;
r = sd_bus_send(q->manager->bus, reply, NULL);
finish:
if (r < 0) {
log_error_errno(r, "Failed to send hostname reply: %m");
sd_bus_reply_method_errno(q->request, -r, NULL);
}
dns_query_free(q);
}
