assert(u);
if (family == AF_INET)
- return (be32toh(u->in.s_addr) & 0xFFFF0000) == (169U << 24 | 254U << 16);
+ return (be32toh(u->in.s_addr) & UINT32_C(0xFFFF0000)) == (UINT32_C(169) << 24 | UINT32_C(254) << 16);
if (family == AF_INET6)
return IN6_IS_ADDR_LINKLOCAL(&u->in6);
return -EAFNOSUPPORT;
}
+int in_addr_is_localhost(int family, const union in_addr_union *u) {
+ assert(u);
+
+ if (family == AF_INET)
+ /* All of 127.x.x.x is localhost. */
+ return (be32toh(u->in.s_addr) & UINT32_C(0xFF000000)) == UINT32_C(127) << 24;
+
+ if (family == AF_INET)
+ return IN6_IS_ADDR_LOOPBACK(&u->in6);
+
+ return -EAFNOSUPPORT;
+}
+
int in_addr_equal(int family, const union in_addr_union *a, const union in_addr_union *b) {
assert(a);
assert(b);
int in_addr_is_null(int family, const union in_addr_union *u);
int in_addr_is_link_local(int family, const union in_addr_union *u);
+int in_addr_is_localhost(int family, const union in_addr_union *u);
int in_addr_equal(int family, const union in_addr_union *a, const union in_addr_union *b);
int in_addr_prefix_intersect(int family, const union in_addr_union *a, unsigned aprefixlen, const union in_addr_union *b, unsigned bprefixlen);
int in_addr_prefix_next(int family, union in_addr_union *u, unsigned prefixlen);
int dns_packet_skip_question(DnsPacket *p);
int dns_packet_extract(DnsPacket *p);
+static inline bool DNS_PACKET_SHALL_CACHE(DnsPacket *p) {
+ /* Never cache data originating from localhost, under the
+ * assumption, that it's coming from a locally DNS forwarder
+ * or server, that is caching on its own. */
+
+ return in_addr_is_localhost(p->family, &p->sender) == 0;
+}
+
enum {
DNS_RCODE_SUCCESS = 0,
DNS_RCODE_FORMERR = 1,
}
/* According to RFC 4795, section 2.9. only the RRs from the answer section shall be cached */
- dns_cache_put(&t->scope->cache, t->key, DNS_PACKET_RCODE(p), p->answer, DNS_PACKET_ANCOUNT(p), 0, p->family, &p->sender);
+ if (DNS_PACKET_SHALL_CACHE(p))
+ dns_cache_put(&t->scope->cache, t->key, DNS_PACKET_RCODE(p), p->answer, DNS_PACKET_ANCOUNT(p), 0, p->family, &p->sender);
if (DNS_PACKET_RCODE(p) == DNS_RCODE_SUCCESS)
dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS);