dhcp,network: implement RFC 4833 (DHCP Timezone option)

This one is simply to add: encode the tzdata timezone in the DHCP
options and optionally make use of it.

5 files changed, 64 insertions, 0 deletions

diff --git a/src/libsystemd-network/dhcp-lease-internal.h b/src/libsystemd-network/dhcp-lease-internal.h
index 5a3fcddb1b..6e247e9865 100644
--- a/src/libsystemd-network/dhcp-lease-internal.h
+++ b/src/libsystemd-network/dhcp-lease-internal.h
@@ -83,6 +83,7 @@ struct sd_dhcp_lease {
         size_t client_id_len;
         uint8_t *vendor_specific;
         size_t vendor_specific_len;
+        char *timezone;
         LIST_HEAD(struct sd_dhcp_raw_option, private_options);
 };
 
diff --git a/src/libsystemd-network/dhcp-protocol.h b/src/libsystemd-network/dhcp-protocol.h
index 4308723f91..88a81d2866 100644
--- a/src/libsystemd-network/dhcp-protocol.h
+++ b/src/libsystemd-network/dhcp-protocol.h
@@ -137,6 +137,8 @@ enum {
         DHCP_OPTION_REBINDING_T2_TIME           = 59,
         DHCP_OPTION_VENDOR_CLASS_IDENTIFIER     = 60,
         DHCP_OPTION_CLIENT_IDENTIFIER           = 61,
+        DHCP_OPTION_NEW_POSIX_TIMEZONE          = 100,
+        DHCP_OPTION_NEW_TZDB_TIMEZONE           = 101,
         DHCP_OPTION_CLASSLESS_STATIC_ROUTE      = 121,
         DHCP_OPTION_PRIVATE_BASE                = 224,
         DHCP_OPTION_PRIVATE_LAST                = 254,
diff --git a/src/libsystemd-network/dhcp-server-internal.h b/src/libsystemd-network/dhcp-server-internal.h
index 58750c4418..24f99f801d 100644
--- a/src/libsystemd-network/dhcp-server-internal.h
+++ b/src/libsystemd-network/dhcp-server-internal.h
@@ -62,6 +62,8 @@ struct sd_dhcp_server {
         size_t pool_size;
         size_t next_offer;
 
+        char *timezone;
+
         Hashmap *leases_by_client_id;
         DHCPLease **bound_leases;
 };
diff --git a/src/libsystemd-network/sd-dhcp-lease.c b/src/libsystemd-network/sd-dhcp-lease.c
index 57369a353d..c312c7cad0 100644
--- a/src/libsystemd-network/sd-dhcp-lease.c
+++ b/src/libsystemd-network/sd-dhcp-lease.c
@@ -608,6 +608,22 @@ int dhcp_lease_parse_options(uint8_t code, uint8_t len, const uint8_t *option,
 
                 break;
 
+        case DHCP_OPTION_NEW_TZDB_TIMEZONE: {
+                _cleanup_free_ char *tz = NULL;
+
+                r = lease_parse_string(option, len, &tz);
+                if (r < 0)
+                        return r;
+
+                if (!timezone_is_valid(tz))
+                        return -EINVAL;
+
+                free(lease->timezone);
+                lease->timezone = tz;
+                tz = NULL;
+                break;
+        }
+
         case DHCP_OPTION_VENDOR_SPECIFIC:
                 if (len >= 1) {
                         free(lease->vendor_specific);
@@ -757,6 +773,10 @@ int sd_dhcp_lease_save(sd_dhcp_lease *lease, const char *lease_file) {
         if (r >= 0)
                 serialize_dhcp_routes(f, "ROUTES", routes, r);
 
+        r = sd_dhcp_lease_get_timezone(lease, &string);
+        if (r >= 0)
+                fprintf(f, "TIMEZONE=%s\n", string);
+
         r = sd_dhcp_lease_get_client_id(lease, &client_id, &client_id_len);
         if (r >= 0) {
                 _cleanup_free_ char *client_id_hex;
@@ -840,6 +860,7 @@ int sd_dhcp_lease_load(sd_dhcp_lease **ret, const char *lease_file) {
                            "ROOT_PATH", &lease->root_path,
                            "ROUTES", &routes,
                            "CLIENTID", &client_id_hex,
+                           "TIMEZONE", &lease->timezone,
                            "VENDOR_SPECIFIC", &vendor_specific_hex,
                            "OPTION_224", &options[0],
                            "OPTION_225", &options[1],
@@ -1026,3 +1047,14 @@ int dhcp_lease_set_client_id(sd_dhcp_lease *lease, const uint8_t *client_id,
 
         return 0;
 }
+
+int sd_dhcp_lease_get_timezone(sd_dhcp_lease *lease, const char **timezone) {
+        assert_return(lease, -EINVAL);
+        assert_return(timezone, -EINVAL);
+
+        if (!lease->timezone)
+                return -ENXIO;
+
+        *timezone = lease->timezone;
+        return 0;
+}
diff --git a/src/libsystemd-network/sd-dhcp-server.c b/src/libsystemd-network/sd-dhcp-server.c
index faeab0fd30..730d95e2c0 100644
--- a/src/libsystemd-network/sd-dhcp-server.c
+++ b/src/libsystemd-network/sd-dhcp-server.c
@@ -136,6 +136,8 @@ sd_dhcp_server *sd_dhcp_server_unref(sd_dhcp_server *server) {
 
         sd_event_unref(server->event);
 
+        free(server->timezone);
+
         while ((lease = hashmap_steal_first(server->leases_by_client_id)))
                 dhcp_lease_free(lease);
         hashmap_free(server->leases_by_client_id);
@@ -474,6 +476,15 @@ static int server_send_ack(sd_dhcp_server *server, DHCPRequest *req,
         if (r < 0)
                 return r;
 
+        if (server->timezone) {
+                r = dhcp_option_append(
+                                &packet->dhcp, req->max_optlen, &offset, 0,
+                                DHCP_OPTION_NEW_TZDB_TIMEZONE,
+                                strlen(server->timezone), server->timezone);
+                if (r < 0)
+                        return r;
+        }
+
         r = dhcp_server_send_packet(server, req, packet, DHCP_ACK, offset);
         if (r < 0)
                 return r;
@@ -993,3 +1004,19 @@ int sd_dhcp_server_forcerenew(sd_dhcp_server *server) {
 
         return r;
 }
+
+int sd_dhcp_server_set_timezone(sd_dhcp_server *server, const char *timezone) {
+        int r;
+
+        assert_return(server, -EINVAL);
+        assert_return(timezone_is_valid(timezone), -EINVAL);
+
+        if (streq_ptr(timezone, server->timezone))
+                return 0;
+
+        r = free_and_strdup(&server->timezone, timezone);
+        if (r < 0)
+                return r;
+
+        return 1;
+}