diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/basic/in-addr-util.c | 15 | ||||
| -rw-r--r-- | src/basic/in-addr-util.h | 1 | ||||
| -rw-r--r-- | src/resolve/resolved-dns-packet.h | 8 | ||||
| -rw-r--r-- | src/resolve/resolved-dns-transaction.c | 3 |
4 files changed, 25 insertions, 2 deletions
diff --git a/src/basic/in-addr-util.c b/src/basic/in-addr-util.c index f4e24121e7..1f61b68efd 100644 --- a/src/basic/in-addr-util.c +++ b/src/basic/in-addr-util.c @@ -44,7 +44,7 @@ int in_addr_is_link_local(int family, const union in_addr_union *u) { 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); @@ -52,6 +52,19 @@ int in_addr_is_link_local(int family, const union in_addr_union *u) { 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); diff --git a/src/basic/in-addr-util.h b/src/basic/in-addr-util.h index 51af08868c..58f55b3418 100644 --- a/src/basic/in-addr-util.h +++ b/src/basic/in-addr-util.h @@ -33,6 +33,7 @@ union in_addr_union { 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); diff --git a/src/resolve/resolved-dns-packet.h b/src/resolve/resolved-dns-packet.h index 48df5dfc53..90b5a7c8bd 100644 --- a/src/resolve/resolved-dns-packet.h +++ b/src/resolve/resolved-dns-packet.h @@ -177,6 +177,14 @@ void dns_packet_rewind(DnsPacket *p, size_t idx); 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, diff --git a/src/resolve/resolved-dns-transaction.c b/src/resolve/resolved-dns-transaction.c index c65c9c9f49..8c4f23a4da 100644 --- a/src/resolve/resolved-dns-transaction.c +++ b/src/resolve/resolved-dns-transaction.c @@ -478,7 +478,8 @@ void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p) { } /* 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); |