Messages in this thread Patch in this message | | | From | Jeffrey Ji <> | Subject | [PATCH v7 net-next] net-core: add InDropOtherhost counter | Date | Mon, 7 Feb 2022 23:57:14 +0000 |
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From: jeffreyji <jeffreyji@google.com>
Increment InDropOtherhost 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 Ip6InDropOtherhost 0 0.0 IpExtInDropOtherhost 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: v7: change InMacError -> InDropOtherhost
v6: rebase onto net-next
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: Brian Vazquez <brianvv@google.com> Signed-off-by: jeffreyji <jeffreyji@google.com> --- Documentation/networking/snmp_counter.rst | 5 +++++ include/uapi/linux/snmp.h | 1 + net/ipv4/ip_input.c | 5 +++-- net/ipv4/proc.c | 1 + net/ipv6/ip6_input.c | 12 +++++++----- net/ipv6/proc.c | 1 + 6 files changed, 18 insertions(+), 7 deletions(-)
diff --git a/Documentation/networking/snmp_counter.rst b/Documentation/networking/snmp_counter.rst index 423d138b5ff3..674f736e4e8b 100644 --- a/Documentation/networking/snmp_counter.rst +++ b/Documentation/networking/snmp_counter.rst @@ -214,6 +214,11 @@ wrong. Kernel verifies the checksum after updating the IcmpInMsgs and before updating IcmpMsgInType[N]. If a packet has bad checksum, the IcmpInMsgs would be updated but none of IcmpMsgInType[N] would be updated. +* IcmpInDropOtherhost + +This counter indicates that the packet was dropped because the destination +MAC address was incorrect. + * IcmpInErrors and IcmpOutErrors Defined by `RFC1213 icmpInErrors`_ and `RFC1213 icmpOutErrors`_ diff --git a/include/uapi/linux/snmp.h b/include/uapi/linux/snmp.h index 904909d020e2..4f247d406b1a 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_INDROPOTHERHOST, /* InDropOtherhost */ __IPSTATS_MIB_MAX }; diff --git a/net/ipv4/ip_input.c b/net/ipv4/ip_input.c index d94f9f7e60c3..db4c36c008ff 100644 --- a/net/ipv4/ip_input.c +++ b/net/ipv4/ip_input.c @@ -450,8 +450,9 @@ static struct sk_buff *ip_rcv_core(struct sk_buff *skb, struct net *net) * that it receives, do not try to analyse it. */ if (skb->pkt_type == PACKET_OTHERHOST) { - drop_reason = SKB_DROP_REASON_OTHERHOST; - goto drop; + __IP_INC_STATS(net, IPSTATS_MIB_INDROPOTHERHOST); + 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 28836071f0a6..2ffa43cff799 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("InDropOtherhost", IPSTATS_MIB_INDROPOTHERHOST), SNMP_MIB_SENTINEL }; diff --git a/net/ipv6/ip6_input.c b/net/ipv6/ip6_input.c index d4b1e2c5aa76..480896e13041 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_INDROPOTHERHOST); + 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..c2d963122d1e 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("Ip6InDropOtherhost", IPSTATS_MIB_INDROPOTHERHOST), SNMP_MIB_SENTINEL }; -- 2.35.0.263.gb82422642f-goog
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