net: Refactor path selection in __ip_route_output_key_hash

VRF device needs the same path selection following lookup to set source
address. Rather than duplicating code, move existing code into a
function that is exported to modules.

Code move only; no functional change.

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

3 files changed, 24 insertions, 15 deletions

diff --git a/include/net/ip_fib.h b/include/net/ip_fib.h
index 7a51fd8d99e4..ac5c6e80586a 100644
--- a/include/net/ip_fib.h
+++ b/include/net/ip_fib.h
@@ -329,6 +329,8 @@ static inline int fib_multipath_hash(__be32 saddr, __be32 daddr)
 }
 
 void fib_select_multipath(struct fib_result *res, int hash);
+void fib_select_path(struct net *net, struct fib_result *res,
+                     struct flowi4 *fl4, int mp_hash);
 
 /* Exported by fib_trie.c */
 void fib_trie_init(void);
diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index 7bd698c3bd3a..af77298c8b4f 100644
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -1557,3 +1557,24 @@ void fib_select_multipath(struct fib_result *res, int hash)
         res->nh_sel = 0;
 }
 #endif
+
+void fib_select_path(struct net *net, struct fib_result *res,
+                     struct flowi4 *fl4, int mp_hash)
+{
+#ifdef CONFIG_IP_ROUTE_MULTIPATH
+        if (res->fi->fib_nhs > 1 && fl4->flowi4_oif == 0) {
+                if (mp_hash < 0)
+                        mp_hash = fib_multipath_hash(fl4->saddr, fl4->daddr);
+                fib_select_multipath(res, mp_hash);
+        }
+        else
+#endif
+        if (!res->prefixlen &&
+            res->table->tb_num_default > 1 &&
+            res->type == RTN_UNICAST && !fl4->flowi4_oif)
+                fib_select_default(fl4, res);
+
+        if (!fl4->saddr)
+                fl4->saddr = FIB_RES_PREFSRC(net, *res);
+}
+EXPORT_SYMBOL_GPL(fib_select_path);
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 54297d3a0559..54e6f456a760 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -2238,21 +2238,7 @@ struct rtable *__ip_route_output_key_hash(struct net *net, struct flowi4 *fl4,
                 goto make_route;
         }
 
-#ifdef CONFIG_IP_ROUTE_MULTIPATH
-        if (res.fi->fib_nhs > 1 && fl4->flowi4_oif == 0) {
-                if (mp_hash < 0)
-                        mp_hash = fib_multipath_hash(fl4->saddr, fl4->daddr);
-                fib_select_multipath(&res, mp_hash);
-        }
-        else
-#endif
-        if (!res.prefixlen &&
-            res.table->tb_num_default > 1 &&
-            res.type == RTN_UNICAST && !fl4->flowi4_oif)
-                fib_select_default(fl4, &res);
-
-        if (!fl4->saddr)
-                fl4->saddr = FIB_RES_PREFSRC(net, res);
+        fib_select_path(net, &res, fl4, mp_hash);
 
         dev_out = FIB_RES_DEV(res);
         fl4->flowi4_oif = dev_out->ifindex;