networkd: rework Domains= setting

Previously, .network files only knew a vaguely defined "Domains=" concept, for which the documentation declared it was
the "DNS domain" for the network connection, without specifying what that means.

With this the Domains setting is reworked, so that there are now "routing" domains and "search" domains. The former are
to be used by resolved to route DNS request to specific network interfaces, the latter is to be used for searching
single-label hostnames with (in addition to being used for routing). Both settings are configured in the "Domains="
setting. Normal domain names listed in it are now considered search domains (for compatibility with existing setups),
while those prefixed with "~" are considered routing domains only. To route all lookups to a specific interface the
routing domain "." may be used, referring to the root domain. An alternative syntax for this is the "*", as was already
implemented before using the "wildcard" domain concept.

This commit adds proper parsers for this new logic, and exposes this via the sd-network API. This information is not
used by resolved yet, this will be added in a later commit.

1 files changed, 10 insertions, 8 deletions

diff --git a/src/systemd/sd-network.h b/src/systemd/sd-network.h
index 653c61a162..ff0d2b191e 100644
--- a/src/systemd/sd-network.h
+++ b/src/systemd/sd-network.h
@@ -64,8 +64,11 @@ int sd_network_get_dns(char ***dns);
  * representations of IP addresses */
 int sd_network_get_ntp(char ***ntp);
 
-/* Get the search/routing domains for all links. */
-int sd_network_get_domains(char ***domains);
+/* Get the search domains for all links. */
+int sd_network_get_search_domains(char ***domains);
+
+/* Get the search domains for all links. */
+int sd_network_get_route_domains(char ***domains);
 
 /* Get setup state from ifindex.
  * Possible states:
@@ -134,8 +137,11 @@ int sd_network_link_get_dnssec_negative_trust_anchors(int ifindex, char ***nta);
 
 int sd_network_link_get_lldp(int ifindex, char **lldp);
 
-/* Get the DNS domain names for a given link. */
-int sd_network_link_get_domains(int ifindex, char ***domains);
+/* Get the search DNS domain names for a given link. */
+int sd_network_link_get_search_domains(int ifindex, char ***domains);
+
+/* Get the route DNS domain names for a given link. */
+int sd_network_link_get_route_domains(int ifindex, char ***domains);
 
 /* Get the CARRIERS to which current link is bound to. */
 int sd_network_link_get_carrier_bound_to(int ifindex, char ***carriers);
@@ -146,10 +152,6 @@ int sd_network_link_get_carrier_bound_by(int ifindex, char ***carriers);
 /* Get the timezone that was learnt on a specific link. */
 int sd_network_link_get_timezone(int ifindex, char **timezone);
 
-/* Returns whether or not domains that don't match any link should be resolved
- * on this link. 1 for yes, 0 for no and negative value for error */
-int sd_network_link_get_wildcard_domain(int ifindex);
-
 /* Monitor object */
 typedef struct sd_network_monitor sd_network_monitor;