net/ipv6: Move gateway validation into helper

Move existing code to validate nexthop into a helper. Follow on patch
adds support for nexthops marked with onlink, and this helper keeps
the complexity of ip6_route_info_create in check.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 49 insertions, 36 deletions

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index aa4411c81e7e..bfd1a06a0700 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -2469,6 +2469,54 @@ static struct rt6_info *ip6_nh_lookup_table(struct net *net,
         return rt;
 }
 
+static int ip6_route_check_nh(struct net *net,
+                              struct fib6_config *cfg,
+                              struct net_device **_dev,
+                              struct inet6_dev **idev)
+{
+        const struct in6_addr *gw_addr = &cfg->fc_gateway;
+        struct net_device *dev = _dev ? *_dev : NULL;
+        struct rt6_info *grt = NULL;
+        int err = -EHOSTUNREACH;
+
+        if (cfg->fc_table) {
+                grt = ip6_nh_lookup_table(net, cfg, gw_addr);
+                if (grt) {
+                        if (grt->rt6i_flags & RTF_GATEWAY ||
+                            (dev && dev != grt->dst.dev)) {
+                                ip6_rt_put(grt);
+                                grt = NULL;
+                        }
+                }
+        }
+
+        if (!grt)
+                grt = rt6_lookup(net, gw_addr, NULL, cfg->fc_ifindex, 1);
+
+        if (!grt)
+                goto out;
+
+        if (dev) {
+                if (dev != grt->dst.dev) {
+                        ip6_rt_put(grt);
+                        goto out;
+                }
+        } else {
+                *_dev = dev = grt->dst.dev;
+                *idev = grt->rt6i_idev;
+                dev_hold(dev);
+                in6_dev_hold(grt->rt6i_idev);
+        }
+
+        if (!(grt->rt6i_flags & RTF_GATEWAY))
+                err = 0;
+
+        ip6_rt_put(grt);
+
+out:
+        return err;
+}
+
 static struct rt6_info *ip6_route_info_create(struct fib6_config *cfg,
                                               struct netlink_ext_ack *extack)
 {
@@ -2664,8 +2712,6 @@ static struct rt6_info *ip6_route_info_create(struct fib6_config *cfg,
                 rt->rt6i_gateway = *gw_addr;
 
                 if (gwa_type != (IPV6_ADDR_LINKLOCAL|IPV6_ADDR_UNICAST)) {
-                        struct rt6_info *grt = NULL;
-
                         /* IPv6 strictly inhibits using not link-local
                            addresses as nexthop address.
                            Otherwise, router will not able to send redirects.
@@ -2682,40 +2728,7 @@ static struct rt6_info *ip6_route_info_create(struct fib6_config *cfg,
                                 goto out;
                         }
 
-                        if (cfg->fc_table) {
-                                grt = ip6_nh_lookup_table(net, cfg, gw_addr);
-
-                                if (grt) {
-                                        if (grt->rt6i_flags & RTF_GATEWAY ||
-                                            (dev && dev != grt->dst.dev)) {
-                                                ip6_rt_put(grt);
-                                                grt = NULL;
-                                        }
-                                }
-                        }
-
-                        if (!grt)
-                                grt = rt6_lookup(net, gw_addr, NULL,
-                                                 cfg->fc_ifindex, 1);
-
-                        err = -EHOSTUNREACH;
-                        if (!grt)
-                                goto out;
-                        if (dev) {
-                                if (dev != grt->dst.dev) {
-                                        ip6_rt_put(grt);
-                                        goto out;
-                                }
-                        } else {
-                                dev = grt->dst.dev;
-                                idev = grt->rt6i_idev;
-                                dev_hold(dev);
-                                in6_dev_hold(grt->rt6i_idev);
-                        }
-                        if (!(grt->rt6i_flags & RTF_GATEWAY))
-                                err = 0;
-                        ip6_rt_put(grt);
-
+                        err = ip6_route_check_nh(net, cfg, &dev, &idev);
                         if (err)
                                 goto out;
                 }