[PATCH 5.15 080/201] net: ipv4: use kfree_skb_reason() in ip_rcv_core()

Greg Kroah-Hartman
2022-07-27T17:08:56Z

From: Menglong Dong <imagedong@tencent.com>

[ Upstream commit 33cba42985c8144eef78d618fc1e51aaa074b169 ]

Replace kfree_skb() with kfree_skb_reason() in ip_rcv_core(). Three new
drop reasons are introduced:

SKB_DROP_REASON_OTHERHOST
SKB_DROP_REASON_IP_CSUM
SKB_DROP_REASON_IP_INHDR

Signed-off-by: Menglong Dong <imagedong@tencent.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
include/linux/skbuff.h | 9 +++++++++
include/trace/events/skb.h | 3 +++
net/ipv4/ip_input.c | 12 ++++++++++--
3 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index b63da0d1a4b2..514fb8074f78 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -318,6 +318,15 @@ enum skb_drop_reason {
SKB_DROP_REASON_SOCKET_FILTER, /* dropped by socket filter */
SKB_DROP_REASON_UDP_CSUM, /* UDP checksum error */
SKB_DROP_REASON_NETFILTER_DROP, /* dropped by netfilter */
+ SKB_DROP_REASON_OTHERHOST, /* packet don't belong to current
+ * host (interface is in promisc
+ * mode)
+ */
+ SKB_DROP_REASON_IP_CSUM, /* IP checksum error */
+ SKB_DROP_REASON_IP_INHDR, /* there is something wrong with
+ * IP header (see
+ * IPSTATS_MIB_INHDRERRORS)
+ */
SKB_DROP_REASON_MAX,
};

diff --git a/include/trace/events/skb.h b/include/trace/events/skb.h
index 3d89f7b09a43..f2b1778485f0 100644
--- a/include/trace/events/skb.h
+++ b/include/trace/events/skb.h
@@ -17,6 +17,9 @@
EM(SKB_DROP_REASON_SOCKET_FILTER, SOCKET_FILTER) \
EM(SKB_DROP_REASON_UDP_CSUM, UDP_CSUM) \
EM(SKB_DROP_REASON_NETFILTER_DROP, NETFILTER_DROP) \
+ EM(SKB_DROP_REASON_OTHERHOST, OTHERHOST) \
+ EM(SKB_DROP_REASON_IP_CSUM, IP_CSUM) \
+ EM(SKB_DROP_REASON_IP_INHDR, IP_INHDR) \
EMe(SKB_DROP_REASON_MAX, MAX)

#undef EM
diff --git a/net/ipv4/ip_input.c b/net/ipv4/ip_input.c
index 3a025c011971..7be18de32e16 100644
--- a/net/ipv4/ip_input.c
+++ b/net/ipv4/ip_input.c
@@ -436,13 +436,16 @@ static int ip_rcv_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
static struct sk_buff *ip_rcv_core(struct sk_buff *skb, struct net *net)
{
const struct iphdr *iph;
+ int drop_reason;
u32 len;

/* 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) {
+ drop_reason = SKB_DROP_REASON_OTHERHOST;
goto drop;
+ }

__IP_UPD_PO_STATS(net, IPSTATS_MIB_IN, skb->len);

@@ -452,6 +455,7 @@ static struct sk_buff *ip_rcv_core(struct sk_buff *skb, struct net *net)
goto out;
}

+ drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;
if (!pskb_may_pull(skb, sizeof(struct iphdr)))
goto inhdr_error;

@@ -488,6 +492,7 @@ static struct sk_buff *ip_rcv_core(struct sk_buff *skb, struct net *net)

len = ntohs(iph->tot_len);
if (skb->len < len) {
+ drop_reason = SKB_DROP_REASON_PKT_TOO_SMALL;
__IP_INC_STATS(net, IPSTATS_MIB_INTRUNCATEDPKTS);
goto drop;
} else if (len < (iph->ihl*4))
@@ -516,11 +521,14 @@ static struct sk_buff *ip_rcv_core(struct sk_buff *skb, struct net *net)
return skb;

csum_error:
+ drop_reason = SKB_DROP_REASON_IP_CSUM;
__IP_INC_STATS(net, IPSTATS_MIB_CSUMERRORS);
inhdr_error:
+ if (drop_reason == SKB_DROP_REASON_NOT_SPECIFIED)
+ drop_reason = SKB_DROP_REASON_IP_INHDR;
__IP_INC_STATS(net, IPSTATS_MIB_INHDRERRORS);
drop:
- kfree_skb(skb);
+ kfree_skb_reason(skb, drop_reason);
out:
return NULL;
}
--
2.35.1