[systemd-devel] [PATCH] networkd: route - allow routes without a gateway

[Gavin Li]

For IPv6, the kernel returns EINVAL if a route is added with the
RTA_GATEWAY attribute set to in6addr_any (::). A route without a
gateway is useful in some situations, such as layer 3 tunneling
(sit, gre, etc.).

This patch prevents the RTA_GATEWAY attribute from being added
when route.in_addr is ip6addr_any (::).
---
 src/network/networkd-route.c | 32 ++++++++++++++++++--------------
 1 file changed, 18 insertions(+), 14 deletions(-)

diff --git a/src/network/networkd-route.c b/src/network/networkd-route.c
index 10d8cd9..82c9e00 100644
--- a/src/network/networkd-route.c
+++ b/src/network/networkd-route.c
@@ -118,13 +118,15 @@ int route_drop(Route *route, Link *link,
                 return r;
         }

-        if (route->family == AF_INET)
-                r = sd_rtnl_message_append_in_addr(req, RTA_GATEWAY,
&route->in_addr.in);
-        else if (route->family == AF_INET6)
-                r = sd_rtnl_message_append_in6_addr(req, RTA_GATEWAY,
&route->in_addr.in6);
-        if (r < 0) {
-                log_error("Could not append RTA_GATEWAY attribute:
%s", strerror(-r));
-                return r;
+        if (!in_addr_is_null(route->family, &route->in_addr)) {
+                if (route->family == AF_INET)
+                        r = sd_rtnl_message_append_in_addr(req,
RTA_GATEWAY, &route->in_addr.in);
+                else if (route->family == AF_INET6)
+                        r = sd_rtnl_message_append_in6_addr(req,
RTA_GATEWAY, &route->in_addr.in6);
+                if (r < 0) {
+                        log_error("Could not append RTA_GATEWAY
attribute: %s", strerror(-r));
+                        return r;
+                }
         }

         if (route->dst_prefixlen) {
@@ -203,13 +205,15 @@ int route_configure(Route *route, Link *link,
                 return r;
         }

-        if (route->family == AF_INET)
-                r = sd_rtnl_message_append_in_addr(req, RTA_GATEWAY,
&route->in_addr.in);
-        else if (route->family == AF_INET6)
-                r = sd_rtnl_message_append_in6_addr(req, RTA_GATEWAY,
&route->in_addr.in6);
-        if (r < 0) {
-                log_error("Could not append RTA_GATEWAY attribute:
%s", strerror(-r));
-                return r;
+        if (!in_addr_is_null(route->family, &route->in_addr)) {
+                if (route->family == AF_INET)
+                        r = sd_rtnl_message_append_in_addr(req,
RTA_GATEWAY, &route->in_addr.in);
+                else if (route->family == AF_INET6)
+                        r = sd_rtnl_message_append_in6_addr(req,
RTA_GATEWAY, &route->in_addr.in6);
+                if (r < 0) {
+                        log_error("Could not append RTA_GATEWAY
attribute: %s", strerror(-r));
+                        return r;
+                }
         }

         if (route->dst_prefixlen) {
-- 
2.1.3