[PATCH net-next 09/18] ipv4: Add fib_check_nh_v6_gw

[David Ahern]

From: David Ahern <dsah...@gmail.com>

Add helper to validate nexthop spec with an IPv6 gateway.

Signed-off-by: David Ahern <dsah...@gmail.com>
---
 net/ipv4/fib_semantics.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index b9f0388a2c70..acbdf0ed6ff8 100644
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -41,6 +41,7 @@
 #include <net/tcp.h>
 #include <net/sock.h>
 #include <net/ip_fib.h>
+#include <net/ip6_fib.h>
 #include <net/netlink.h>
 #include <net/nexthop.h>
 #include <net/lwtunnel.h>
@@ -841,6 +842,30 @@ bool fib_metrics_match(struct fib_config *cfg, struct 
fib_info *fi)
        return true;
 }
 
+static int fib_check_nh_v6_gw(struct net *net, struct fib_nh *nh,
+                             u32 table, struct netlink_ext_ack *extack)
+{
+       struct fib6_config cfg = {
+               .fc_table = table,
+               .fc_flags = nh->fib_nh_flags | RTF_GATEWAY,
+               .fc_ifindex = nh->fib_nh_oif,
+               .fc_gateway = nh->fib_nh_gw6,
+       };
+       struct fib6_nh fib6_nh = {};
+       int err;
+
+       err = ipv6_stub->fib6_nh_init(net, &fib6_nh, &cfg, GFP_KERNEL, extack);
+       if (!err) {
+               nh->fib_nh_dev = fib6_nh.fib_nh_dev;
+               dev_hold(nh->fib_nh_dev);
+               nh->fib_nh_oif = nh->fib_nh_dev->ifindex;
+               nh->fib_nh_scope = RT_SCOPE_LINK;
+       }
+
+       ipv6_stub->fib6_nh_release(&fib6_nh);
+
+       return err;
+}
 
 /*
  * Picture
@@ -1023,6 +1048,8 @@ static int fib_check_nh(struct fib_config *cfg, struct 
fib_nh *nh,
 
        if (nh->fib_nh_gw_family == AF_INET)
                err = fib_check_nh_v4_gw(net, nh, table, cfg->fc_scope, extack);
+       else if (nh->fib_nh_gw_family == AF_INET6)
+               err = fib_check_nh_v6_gw(net, nh, table, extack);
        else
                err = fib_check_nh_nongw(net, nh, extack);
 
-- 
2.11.0