return 0; /* static */
}
+static int dhcp4_find_gateway_for_destination(
+ Link *link,
+ const struct in_addr *destination,
+ uint8_t prefixlength,
+ bool allow_null,
+ struct in_addr *ret) {
+
+ _cleanup_free_ sd_dhcp_route **routes = NULL;
+ size_t n_routes = 0;
+ bool is_classless, reachable;
+ uint8_t max_prefixlen = UINT8_MAX;
+ struct in_addr gw;
+ int r;
+
+ assert(link);
+ assert(link->dhcp_lease);
+ assert(destination);
+ assert(ret);
+
+ /* This tries to find the most suitable gateway for an address or address range.
+ * E.g. if the server provides the default gateway 192.168.0.1 and a classless static route for
+ * 8.0.0.0/8 with gateway 192.168.0.2, then this returns 192.168.0.2 for 8.8.8.8/32, and 192.168.0.1
+ * for 9.9.9.9/32. If 'allow_null' flag is set, and the input address or address range is in the
+ * assigned network, then the default gateway will be ignored and the null address will be returned
+ * unless a matching non-default gateway found. */
+
+ r = dhcp4_prefix_covers(link, destination, prefixlength);
+ if (r < 0)
+ return r;
+ reachable = r > 0;
+
+ r = dhcp4_get_classless_static_or_static_routes(link, &routes, &n_routes);
+ if (r < 0 && r != -ENODATA)
+ return r;
+ is_classless = r > 0;
+
+ /* First, find most suitable gateway. */
+ FOREACH_ARRAY(e, routes, n_routes) {
+ struct in_addr dst;
+ uint8_t len;
+
+ r = sd_dhcp_route_get_destination(*e, &dst);
+ if (r < 0)
+ return r;
+
+ r = sd_dhcp_route_get_destination_prefix_length(*e, &len);
+ if (r < 0)
+ return r;
+
+ r = in4_addr_prefix_covers_full(&dst, len, destination, prefixlength);
+ if (r < 0)
+ return r;
+ if (r == 0)
+ continue;
+
+ if (max_prefixlen != UINT8_MAX && max_prefixlen > len)
+ continue;
+
+ r = sd_dhcp_route_get_gateway(*e, &gw);
+ if (r < 0)
+ return r;
+
+ max_prefixlen = len;
+ }
+
+ /* Found a suitable gateway in classless static routes or static routes. */
+ if (max_prefixlen != UINT8_MAX) {
+ if (max_prefixlen == 0 && reachable && allow_null)
+ /* Do not return the default gateway, if the destination is in the assigned network. */
+ *ret = (struct in_addr) {};
+ else
+ *ret = gw;
+ return 0;
+ }
+
+ /* When the destination is in the assigned network, return the null address if allowed. */
+ if (reachable && allow_null) {
+ *ret = (struct in_addr) {};
+ return 0;
+ }
+
+ /* According to RFC 3442: If the DHCP server returns both a Classless Static Routes option and
+ * a Router option, the DHCP client MUST ignore the Router option. */
+ if (!is_classless) {
+ r = dhcp4_get_router(link, ret);
+ if (r >= 0)
+ return 0;
+ if (r != -ENODATA)
+ return r;
+ }
+
+ if (!reachable)
+ return -EHOSTUNREACH; /* Not in the same network, cannot reach the destination. */
+
+ assert(!allow_null);
+ return -ENODATA; /* No matching gateway found. */
+}
+
static int dhcp4_remove_address_and_routes(Link *link, bool only_marked) {
Address *address;
Route *route;
return 0;
}
-static int dhcp4_request_semi_static_routes(Link *link, const struct in_addr *gw) {
+static int dhcp4_request_semi_static_routes(Link *link) {
Route *rt;
int r;
assert(link);
assert(link->dhcp_lease);
assert(link->network);
- assert(gw);
-
- if (in4_addr_is_null(gw))
- return 0;
HASHMAP_FOREACH(rt, link->network->routes_by_section) {
_cleanup_(route_freep) Route *route = NULL;
+ struct in_addr gw;
if (!rt->gateway_from_dhcp_or_ra)
continue;
if (rt->gw_family != AF_INET)
continue;
- r = dhcp4_request_route_to_gateway(link, gw);
+ assert(rt->family == AF_INET);
+
+ r = dhcp4_find_gateway_for_destination(link, &rt->dst.in, rt->dst_prefixlen, /* allow_null = */ false, &gw);
+ if (IN_SET(r, -EHOSTUNREACH, -ENODATA)) {
+ log_link_debug_errno(link, r, "DHCP: Cannot find suitable gateway for destination %s of semi-static route, ignoring: %m",
+ IN4_ADDR_PREFIX_TO_STRING(&rt->dst.in, rt->dst_prefixlen));
+ continue;
+ }
+ if (r < 0)
+ return r;
+
+ r = dhcp4_request_route_to_gateway(link, &gw);
if (r < 0)
return r;
if (r < 0)
return r;
- route->gw.in = *gw;
+ route->gw.in = gw;
r = dhcp4_request_route(TAKE_PTR(route), link);
if (r < 0)
static int dhcp4_request_routes_to_servers(
Link *link,
const struct in_addr *servers,
- size_t n_servers,
- const struct in_addr *gw) {
+ size_t n_servers) {
int r;
assert(link->dhcp_lease);
assert(link->network);
assert(servers || n_servers == 0);
- assert(gw);
FOREACH_ARRAY(dst, servers, n_servers) {
_cleanup_(route_freep) Route *route = NULL;
+ struct in_addr gw;
if (in4_addr_is_null(dst))
continue;
+ r = dhcp4_find_gateway_for_destination(link, dst, 32, /* allow_null = */ true, &gw);
+ if (r == -EHOSTUNREACH) {
+ log_link_debug_errno(link, r, "DHCP: Cannot find suitable gateway for destination %s, ignoring: %m",
+ IN4_ADDR_PREFIX_TO_STRING(dst, 32));
+ continue;
+ }
+ if (r < 0)
+ return r;
+
r = route_new(&route);
if (r < 0)
return r;
route->dst.in = *dst;
route->dst_prefixlen = 32;
- r = dhcp4_request_route_auto(TAKE_PTR(route), link, gw, /* force_use_gw = */ false);
+ r = dhcp4_request_route_auto(TAKE_PTR(route), link, &gw, /* force_use_gw = */ false);
if (r < 0)
return r;
}
return 0;
}
-static int dhcp4_request_routes_to_dns(Link *link, const struct in_addr *gw) {
+static int dhcp4_request_routes_to_dns(Link *link) {
const struct in_addr *dns;
int r;
assert(link);
assert(link->dhcp_lease);
assert(link->network);
- assert(gw);
if (!link->network->dhcp_use_dns ||
!link->network->dhcp_routes_to_dns)
if (r < 0)
return r;
- return dhcp4_request_routes_to_servers(link, dns, r, gw);
+ return dhcp4_request_routes_to_servers(link, dns, r);
}
-static int dhcp4_request_routes_to_ntp(Link *link, const struct in_addr *gw) {
+static int dhcp4_request_routes_to_ntp(Link *link) {
const struct in_addr *ntp;
int r;
assert(link);
assert(link->dhcp_lease);
assert(link->network);
- assert(gw);
if (!link->network->dhcp_use_ntp ||
!link->network->dhcp_routes_to_ntp)
if (r < 0)
return r;
- return dhcp4_request_routes_to_servers(link, ntp, r, gw);
+ return dhcp4_request_routes_to_servers(link, ntp, r);
}
static int dhcp4_request_routes(Link *link) {
return log_link_error_errno(link, r, "DHCP error: Could not request gateway: %m");
}
- r = dhcp4_request_semi_static_routes(link, &gw);
+ r = dhcp4_request_semi_static_routes(link);
if (r < 0)
return log_link_error_errno(link, r, "DHCP error: Could not request routes with Gateway=_dhcp4 setting: %m");
- r = dhcp4_request_routes_to_dns(link, &gw);
+ r = dhcp4_request_routes_to_dns(link);
if (r < 0)
return log_link_error_errno(link, r, "DHCP error: Could not request routes to DNS servers: %m");
- r = dhcp4_request_routes_to_ntp(link, &gw);
+ r = dhcp4_request_routes_to_ntp(link);
if (r < 0)
return log_link_error_errno(link, r, "DHCP error: Could not request routes to NTP servers: %m");
projects / thirdparty / systemd.git / commitdiff
