ipv4: Fix incorrect error code when adding an unreachable route

Trying to add an unreachable route incorrectly returns -ESRCH if
if custom FIB rules are present:

[root@localhost ~]# ip route add 74.125.31.199 dev eth0 via 1.2.3.4
RTNETLINK answers: Network is unreachable
[root@localhost ~]# ip rule add to 55.66.77.88 table 200
[root@localhost ~]# ip route add 74.125.31.199 dev eth0 via 1.2.3.4
RTNETLINK answers: No such process
[root@localhost ~]#

Commit 1d4c8e849ee00216c565c0985cf9e660d3876560 ("[NET]: Change "not found"
return value for rule lookup") changed fib_rules_lookup()
to use -ESRCH as a "not found" code internally, but for user space it
should be translated into -ENETUNREACH. Handle the translation centrally in
ipv4-specific fib_lookup(), leaving the DECnet case alone.

On a related note, commit 1efba5eaef3edb216ed7fd021bc1db05e11a5a7d
("ipv4: removed redundant conditional") removed a similar translation from
ip_route_input_slow() prematurely AIUI.

Fixes: 1efba5eaef3e ("ipv4: removed redundant conditional")
Signed-off-by: Panu Matilainen <pmatilai@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/fib_rules.c b/net/ipv4/fib_rules.c
index f2e15738534d316ed0c50b8be2e1976fa03052c5..8f7bd56955b0dc35bb89e4fd0d3fe19fe9b53a47 100644 (file)
--- a/net/ipv4/fib_rules.c
+++ b/net/ipv4/fib_rules.c
@@ -62,6 +62,10 @@ int __fib_lookup(struct net *net, struct flowi4 *flp, struct fib_result *res)
        else
                res->tclassid = 0;
 #endif
+
+       if (err == -ESRCH)
+               err = -ENETUNREACH;
+
        return err;
 }
 EXPORT_SYMBOL_GPL(__fib_lookup);