static int dns_transaction_make_packet(DnsTransaction *t) {
_cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
int r;
assert(t);
if (t->sent)
return 0;
r = dns_packet_new_query(&p, t->scope->protocol, 0);
if (r < 0)
return r;
r = dns_scope_good_key(t->scope, t->key);
if (r < 0)
return r;
if (r == 0)
return -EDOM;
r = dns_packet_append_key(p, t->key, NULL);
if (r < 0)
return r;
DNS_PACKET_HEADER(p)->qdcount = htobe16(1);
DNS_PACKET_HEADER(p)->id = t->id;
t->sent = p;
p = NULL;
return 0;
}
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_transaction_make_packet(DnsTransaction *t) {
_cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
unsigned n, added = 0;
int r;
assert(t);
if (t->sent)
return 0;
r = dns_packet_new_query(&p, t->scope->protocol, 0);
if (r < 0)
return r;
for (n = 0; n < t->question->n_keys; n++) {
r = dns_scope_good_key(t->scope, t->question->keys[n]);
if (r < 0)
return r;
if (r == 0)
continue;
r = dns_packet_append_key(p, t->question->keys[n], NULL);
if (r < 0)
return r;
added++;
}
if (added <= 0)
return -EDOM;
DNS_PACKET_HEADER(p)->qdcount = htobe16(added);
DNS_PACKET_HEADER(p)->id = t->id;
t->sent = p;
p = NULL;
return 0;
}
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++;
}
