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:
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..04a36352f677 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_BAD_DEST_MAC,
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..379ef6b46920 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_BAD_DEST_MAC);
+ 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..f6245fba7699 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_BAD_DEST_MAC);
+ 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.rc0.227.g00780c9af4-goog
Reviewed-by: Brian Vazquez <[email protected]>
On Tue, Jan 25, 2022 at 3:24 PM Jeffrey Ji <[email protected]> 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.
>
> Changelog:
>
> 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..04a36352f677 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_BAD_DEST_MAC,
> 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..379ef6b46920 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_BAD_DEST_MAC);
> + 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..f6245fba7699 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_BAD_DEST_MAC);
> + 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.rc0.227.g00780c9af4-goog
>
On Tue, 25 Jan 2022 23:24:24 +0000 Jeffrey Ji wrote:
> 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..04a36352f677 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_BAD_DEST_MAC,
Ah, sorry I missed that you pulled in the reason in v3, I thought you'd
leave it to Menglong. Either way is fine, but "BAD_DEST_MAC" is
probably not the most fortunate name for this reason code.
Menglong had OTHERHOST - that seems more intuitive to me, the MAC
address is not bad, it's just not the address of the local host.