From: jeffreyji <[email protected]>
Increment InMacErrors counter when packet dropped due to incorrect dest
MAC addr.
An example when this drop can occur is when manually crafting raw
packets that will be consumed by a user space application via a tap
device. For testing purposes local traffic was generated using trafgen
for the client and netcat to start a server
example output from nstat:
\~# nstat -a | grep InMac
Ip6InMacErrors 0 0.0
IpExtInMacErrors 1 0.0
Tested: Created 2 netns, sent 1 packet using trafgen from 1 to the other
with "{eth(daddr=$INCORRECT_MAC...}", verified that nstat showed the
counter was incremented.
Signed-off-by: jeffreyji <[email protected]>
---
include/uapi/linux/snmp.h | 1 +
net/ipv4/ip_input.c | 4 +++-
net/ipv4/proc.c | 1 +
net/ipv6/ip6_input.c | 1 +
net/ipv6/proc.c | 1 +
5 files changed, 7 insertions(+), 1 deletion(-)
diff --git a/include/uapi/linux/snmp.h b/include/uapi/linux/snmp.h
index 904909d020e2..ac2fac12dd7d 100644
--- a/include/uapi/linux/snmp.h
+++ b/include/uapi/linux/snmp.h
@@ -57,6 +57,7 @@ enum
IPSTATS_MIB_ECT0PKTS, /* InECT0Pkts */
IPSTATS_MIB_CEPKTS, /* InCEPkts */
IPSTATS_MIB_REASM_OVERLAPS, /* ReasmOverlaps */
+ IPSTATS_MIB_INMACERRORS, /* InMacErrors */
__IPSTATS_MIB_MAX
};
diff --git a/net/ipv4/ip_input.c b/net/ipv4/ip_input.c
index 3a025c011971..0961585f7c02 100644
--- a/net/ipv4/ip_input.c
+++ b/net/ipv4/ip_input.c
@@ -441,8 +441,10 @@ static struct sk_buff *ip_rcv_core(struct sk_buff *skb, struct net *net)
/* When the interface is in promisc. mode, drop all the crap
* that it receives, do not try to analyse it.
*/
- if (skb->pkt_type == PACKET_OTHERHOST)
+ if (skb->pkt_type == PACKET_OTHERHOST) {
+ __IP_INC_STATS(net, IPSTATS_MIB_INMACERRORS);
goto drop;
+ }
__IP_UPD_PO_STATS(net, IPSTATS_MIB_IN, skb->len);
diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c
index f30273afb539..dfe0a1dbf8e9 100644
--- a/net/ipv4/proc.c
+++ b/net/ipv4/proc.c
@@ -117,6 +117,7 @@ static const struct snmp_mib snmp4_ipextstats_list[] = {
SNMP_MIB_ITEM("InECT0Pkts", IPSTATS_MIB_ECT0PKTS),
SNMP_MIB_ITEM("InCEPkts", IPSTATS_MIB_CEPKTS),
SNMP_MIB_ITEM("ReasmOverlaps", IPSTATS_MIB_REASM_OVERLAPS),
+ SNMP_MIB_ITEM("InMacErrors", IPSTATS_MIB_INMACERRORS),
SNMP_MIB_SENTINEL
};
diff --git a/net/ipv6/ip6_input.c b/net/ipv6/ip6_input.c
index 80256717868e..2903869274ca 100644
--- a/net/ipv6/ip6_input.c
+++ b/net/ipv6/ip6_input.c
@@ -150,6 +150,7 @@ static struct sk_buff *ip6_rcv_core(struct sk_buff *skb, struct net_device *dev,
struct inet6_dev *idev;
if (skb->pkt_type == PACKET_OTHERHOST) {
+ __IP6_INC_STATS(net, idev, IPSTATS_MIB_INMACERRORS);
kfree_skb(skb);
return NULL;
}
diff --git a/net/ipv6/proc.c b/net/ipv6/proc.c
index d6306aa46bb1..76e6119ba558 100644
--- a/net/ipv6/proc.c
+++ b/net/ipv6/proc.c
@@ -84,6 +84,7 @@ static const struct snmp_mib snmp6_ipstats_list[] = {
SNMP_MIB_ITEM("Ip6InECT1Pkts", IPSTATS_MIB_ECT1PKTS),
SNMP_MIB_ITEM("Ip6InECT0Pkts", IPSTATS_MIB_ECT0PKTS),
SNMP_MIB_ITEM("Ip6InCEPkts", IPSTATS_MIB_CEPKTS),
+ SNMP_MIB_ITEM("Ip6InMacErrors", IPSTATS_MIB_INMACERRORS),
SNMP_MIB_SENTINEL
};
--
2.35.0.rc0.227.g00780c9af4-goog
On Tue, 25 Jan 2022 19:07:17 +0000 Jeffrey Ji wrote:
> From: jeffreyji <[email protected]>
>
> Increment InMacErrors counter when packet dropped due to incorrect dest
> MAC addr.
>
> An example when this drop can occur is when manually crafting raw
> packets that will be consumed by a user space application via a tap
> device. For testing purposes local traffic was generated using trafgen
> for the client and netcat to start a server
>
> example output from nstat:
> \~# nstat -a | grep InMac
> Ip6InMacErrors 0 0.0
> IpExtInMacErrors 1 0.0
>
> Tested: Created 2 netns, sent 1 packet using trafgen from 1 to the other
> with "{eth(daddr=$INCORRECT_MAC...}", verified that nstat showed the
> counter was incremented.
> diff --git a/net/ipv6/ip6_input.c b/net/ipv6/ip6_input.c
> index 80256717868e..2903869274ca 100644
> --- a/net/ipv6/ip6_input.c
> +++ b/net/ipv6/ip6_input.c
> @@ -150,6 +150,7 @@ static struct sk_buff *ip6_rcv_core(struct sk_buff *skb, struct net_device *dev,
> struct inet6_dev *idev;
>
> if (skb->pkt_type == PACKET_OTHERHOST) {
> + __IP6_INC_STATS(net, idev, IPSTATS_MIB_INMACERRORS);
Clang points out idev is not initialized at this point, yet.