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, 22 deletions

diff --git a/src/libsystemd/sd-network/sd-network.c b/src/libsystemd/sd-network/sd-network.c
index c1f5867ee4..4b7fad9c81 100644
--- a/src/libsystemd/sd-network/sd-network.c
+++ b/src/libsystemd/sd-network/sd-network.c
@@ -95,10 +95,14 @@ _public_ int sd_network_get_ntp(char ***ret) {
         return network_get_strv("NTP", ret);
 }
 
-_public_ int sd_network_get_domains(char ***ret) {
+_public_ int sd_network_get_search_domains(char ***ret) {
         return network_get_strv("DOMAINS", ret);
 }
 
+_public_ int sd_network_get_route_domains(char ***ret) {
+        return network_get_strv("ROUTE_DOMAINS", ret);
+}
+
 static int network_link_get_string(int ifindex, const char *field, char **ret) {
         _cleanup_free_ char *s = NULL, *p = NULL;
         int r;
@@ -222,10 +226,14 @@ _public_ int sd_network_link_get_ntp(int ifindex, char ***ret) {
         return network_link_get_strv(ifindex, "NTP", ret);
 }
 
-_public_ int sd_network_link_get_domains(int ifindex, char ***ret) {
+_public_ int sd_network_link_get_search_domains(int ifindex, char ***ret) {
         return network_link_get_strv(ifindex, "DOMAINS", ret);
 }
 
+_public_ int sd_network_link_get_route_domains(int ifindex, char ***ret) {
+        return network_link_get_strv(ifindex, "ROUTE_DOMAINS", ret);
+}
+
 _public_ int sd_network_link_get_carrier_bound_to(int ifindex, char ***ret) {
         return network_link_get_strv(ifindex, "CARRIER_BOUND_TO", ret);
 }
@@ -234,26 +242,6 @@ _public_ int sd_network_link_get_carrier_bound_by(int ifindex, char ***ret) {
         return network_link_get_strv(ifindex, "CARRIER_BOUND_BY", ret);
 }
 
-_public_ int sd_network_link_get_wildcard_domain(int ifindex) {
-        _cleanup_free_ char *p = NULL, *s = NULL;
-        int r;
-
-        assert_return(ifindex > 0, -EINVAL);
-
-        if (asprintf(&p, "/run/systemd/netif/links/%d", ifindex) < 0)
-                return -ENOMEM;
-
-        r = parse_env_file(p, NEWLINE, "WILDCARD_DOMAIN", &s, NULL);
-        if (r == -ENOENT)
-                return -ENODATA;
-        if (r < 0)
-                return r;
-        if (isempty(s))
-                return -ENODATA;
-
-        return parse_boolean(s);
-}
-
 static inline int MONITOR_TO_FD(sd_network_monitor *m) {
         return (int) (unsigned long) m - 1;
 }