ipv4: add LINUX_MIB_IPRPFILTER snmp counter
Christoph Lameter mentioned that packets could be dropped in input path
because of rp_filter settings, without any SNMP counter being
incremented. System administrator can have a hard time to track the
problem.
This patch introduces a new counter, LINUX_MIB_IPRPFILTER, incremented
each time we drop a packet because Reverse Path Filter triggers.
(We receive an IPv4 datagram on a given interface, and find the route to
send an answer would use another interface)
netstat -s | grep IPReversePathFilter
IPReversePathFilter: 21714
Reported-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 4f0ed45..e830f7a 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -284,7 +284,7 @@
if (no_addr)
goto last_resort;
if (rpf == 1)
- goto e_inval;
+ goto e_rpf;
fl.oif = dev->ifindex;
ret = 0;
@@ -299,7 +299,7 @@
last_resort:
if (rpf)
- goto e_inval;
+ goto e_rpf;
*spec_dst = inet_select_addr(dev, 0, RT_SCOPE_UNIVERSE);
*itag = 0;
return 0;
@@ -308,6 +308,8 @@
fib_res_put(&res);
e_inval:
return -EINVAL;
+e_rpf:
+ return -EXDEV;
}
static inline __be32 sk_extract_addr(struct sockaddr *addr)