resolved: add a concept of "authenticated" responses

This adds a new SD_RESOLVED_AUTHENTICATED flag for responses we return
on the bus. When set, then the data has been authenticated. For now this
mostly reflects the DNSSEC AD bit, if DNSSEC=trust is set. As soon as
the client-side validation is complete it will be hooked up to this flag
too.

We also set this bit whenver we generated the data ourselves, for
example, because it originates in our local LLMNR zone, or from the
built-in trust anchor database.

The "systemd-resolve-host" tool has been updated to show the flag state
for the data it shows.

1 files changed, 7 insertions, 4 deletions

diff --git a/src/resolve/resolved-dns-packet.h b/src/resolve/resolved-dns-packet.h
index ffa6c44213..aa2823cfb9 100644
--- a/src/resolve/resolved-dns-packet.h
+++ b/src/resolve/resolved-dns-packet.h
@@ -225,16 +225,19 @@ DnsProtocol dns_protocol_from_string(const char *s) _pure_;
 #define LLMNR_MULTICAST_IPV4_ADDRESS ((struct in_addr) { .s_addr = htobe32(224U << 24 | 252U) })
 #define LLMNR_MULTICAST_IPV6_ADDRESS ((struct in6_addr) { .s6_addr = { 0xFF, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x03 } })
 
-static inline uint64_t SD_RESOLVED_FLAGS_MAKE(DnsProtocol protocol, int family) {
+static inline uint64_t SD_RESOLVED_FLAGS_MAKE(DnsProtocol protocol, int family, bool authenticated) {
+        uint64_t f;
 
-        /* Converts a protocol + family into a flags field as used in queries */
+        /* Converts a protocol + family into a flags field as used in queries and responses */
+
+        f = authenticated ? SD_RESOLVED_AUTHENTICATED : 0;
 
         switch (protocol) {
         case DNS_PROTOCOL_DNS:
-                return SD_RESOLVED_DNS;
+                return f|SD_RESOLVED_DNS;
 
         case DNS_PROTOCOL_LLMNR:
-                return family == AF_INET6 ? SD_RESOLVED_LLMNR_IPV6 : SD_RESOLVED_LLMNR_IPV4;
+                return f|(family == AF_INET6 ? SD_RESOLVED_LLMNR_IPV6 : SD_RESOLVED_LLMNR_IPV4);
 
         default:
                 break;