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.
changelog:
v5:
Change from SKB_DROP_REASON_BAD_DEST_MAC to SKB_DROP_REASON_OTHERHOST
v3-4:
Remove Change-Id
v2:
Use skb_free_reason() for tracing
Add real-life example in patch msg
Signed-off-by: jeffreyji <[email protected]>
---
include/linux/skbuff.h | 1 +
include/uapi/linux/snmp.h | 1 +
net/ipv4/ip_input.c | 7 +++++--
net/ipv4/proc.c | 1 +
net/ipv6/ip6_input.c | 12 +++++++-----
net/ipv6/proc.c | 1 +
6 files changed, 16 insertions(+), 7 deletions(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index bf11e1fbd69b..c831e3a502f2 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -320,6 +320,7 @@ enum skb_drop_reason {
SKB_DROP_REASON_TCP_CSUM,
SKB_DROP_REASON_TCP_FILTER,
SKB_DROP_REASON_UDP_CSUM,
+ SKB_DROP_REASON_OTHERHOST,
SKB_DROP_REASON_MAX,
};
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..780892526166 100644
--- a/net/ipv4/ip_input.c
+++ b/net/ipv4/ip_input.c
@@ -441,8 +441,11 @@ 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)
- goto drop;
+ if (skb->pkt_type == PACKET_OTHERHOST) {
+ __IP_INC_STATS(net, IPSTATS_MIB_INMACERRORS);
+ kfree_skb_reason(skb, SKB_DROP_REASON_OTHERHOST);
+ return NULL;
+ }
__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..da18d9159647 100644
--- a/net/ipv6/ip6_input.c
+++ b/net/ipv6/ip6_input.c
@@ -149,15 +149,17 @@ static struct sk_buff *ip6_rcv_core(struct sk_buff *skb, struct net_device *dev,
u32 pkt_len;
struct inet6_dev *idev;
- if (skb->pkt_type == PACKET_OTHERHOST) {
- kfree_skb(skb);
- return NULL;
- }
-
rcu_read_lock();
idev = __in6_dev_get(skb->dev);
+ if (skb->pkt_type == PACKET_OTHERHOST) {
+ __IP6_INC_STATS(net, idev, IPSTATS_MIB_INMACERRORS);
+ rcu_read_unlock();
+ kfree_skb_reason(skb, SKB_DROP_REASON_OTHERHOST);
+ return NULL;
+ }
+
__IP6_UPD_PO_STATS(net, idev, IPSTATS_MIB_IN, skb->len);
if ((skb = skb_share_check(skb, GFP_ATOMIC)) == 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.rc2.247.g8bbb082509-goog
On Mon, 31 Jan 2022 18:15:07 +0000 Jeffrey Ji wrote:
> diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
> index bf11e1fbd69b..c831e3a502f2 100644
> --- a/include/linux/skbuff.h
> +++ b/include/linux/skbuff.h
> @@ -320,6 +320,7 @@ enum skb_drop_reason {
> SKB_DROP_REASON_TCP_CSUM,
> SKB_DROP_REASON_TCP_FILTER,
This got renamed on Thursday, you need to rebase on latest net-next.
> SKB_DROP_REASON_UDP_CSUM,
> + SKB_DROP_REASON_OTHERHOST,
> SKB_DROP_REASON_MAX,
> };