dhcp,network: support emitting DNS/NTP server information from DHCP server

For now, this is very simple and IP addresses have to be configured
manually.

2 files changed, 75 insertions, 0 deletions

diff --git a/src/libsystemd-network/dhcp-server-internal.h b/src/libsystemd-network/dhcp-server-internal.h
index 4f562c73ef..6cc794c937 100644
--- a/src/libsystemd-network/dhcp-server-internal.h
+++ b/src/libsystemd-network/dhcp-server-internal.h
@@ -63,6 +63,9 @@ struct sd_dhcp_server {
 
         char *timezone;
 
+        struct in_addr *ntp, *dns;
+        unsigned n_ntp, n_dns;
+
         Hashmap *leases_by_client_id;
         DHCPLease **bound_leases;
 
diff --git a/src/libsystemd-network/sd-dhcp-server.c b/src/libsystemd-network/sd-dhcp-server.c
index 35564d8317..a46858258b 100644
--- a/src/libsystemd-network/sd-dhcp-server.c
+++ b/src/libsystemd-network/sd-dhcp-server.c
@@ -145,6 +145,8 @@ sd_dhcp_server *sd_dhcp_server_unref(sd_dhcp_server *server) {
         sd_event_unref(server->event);
 
         free(server->timezone);
+        free(server->dns);
+        free(server->ntp);
 
         while ((lease = hashmap_steal_first(server->leases_by_client_id)))
                 dhcp_lease_free(lease);
@@ -481,6 +483,24 @@ static int server_send_ack(sd_dhcp_server *server, DHCPRequest *req,
         if (r < 0)
                 return r;
 
+        if (server->n_dns > 0) {
+                r = dhcp_option_append(
+                                &packet->dhcp, req->max_optlen, &offset, 0,
+                                DHCP_OPTION_DOMAIN_NAME_SERVER,
+                                sizeof(struct in_addr) * server->n_dns, server->dns);
+                if (r < 0)
+                        return r;
+        }
+
+        if (server->n_ntp > 0) {
+                r = dhcp_option_append(
+                                &packet->dhcp, req->max_optlen, &offset, 0,
+                                DHCP_OPTION_NTP_SERVER,
+                                sizeof(struct in_addr) * server->n_ntp, server->ntp);
+                if (r < 0)
+                        return r;
+        }
+
         if (server->timezone) {
                 r = dhcp_option_append(
                                 &packet->dhcp, req->max_optlen, &offset, 0,
@@ -1042,3 +1062,55 @@ int sd_dhcp_server_set_default_lease_time(sd_dhcp_server *server, uint32_t t) {
         server->default_lease_time = t;
         return 1;
 }
+
+int sd_dhcp_server_set_dns(sd_dhcp_server *server, const struct in_addr dns[], unsigned n) {
+        assert_return(server, -EINVAL);
+        assert_return(dns || n <= 0, -EINVAL);
+
+        if (server->n_dns == n &&
+            memcmp(server->dns, dns, sizeof(struct in_addr) * n) == 0)
+                return 0;
+
+        if (n <= 0) {
+                server->dns = mfree(server->dns);
+                server->n_dns = 0;
+        } else {
+                struct in_addr *c;
+
+                c = newdup(struct in_addr, dns, n);
+                if (!c)
+                        return -ENOMEM;
+
+                free(server->dns);
+                server->dns = c;
+                server->n_dns = n;
+        }
+
+        return 1;
+}
+
+int sd_dhcp_server_set_ntp(sd_dhcp_server *server, const struct in_addr ntp[], unsigned n) {
+        assert_return(server, -EINVAL);
+        assert_return(ntp || n <= 0, -EINVAL);
+
+        if (server->n_ntp == n &&
+            memcmp(server->ntp, ntp, sizeof(struct in_addr) * n) == 0)
+                return 0;
+
+        if (n <= 0) {
+                server->ntp = mfree(server->ntp);
+                server->n_ntp = 0;
+        } else {
+                struct in_addr *c;
+
+                c = newdup(struct in_addr, ntp, n);
+                if (!c)
+                        return -ENOMEM;
+
+                free(server->ntp);
+                server->ntp = c;
+                server->n_ntp = n;
+        }
+
+        return 1;
+}