[PATCH net-next 03/19] net: tcp: use kfree_skb_reason() for tcp_v6_rcv()

From: menglong8.dong@gmail.com
To: dsahern@kernel.org, kuba@kernel.org
Cc: edumazet@google.com, davem@davemloft.net, rostedt@goodmis.org,
	mingo@redhat.com, yoshfuji@linux-ipv6.org, ast@kernel.org,
	daniel@iogearbox.net, hawk@kernel.org, john.fastabend@gmail.com,
	imagedong@tencent.com, talalahmad@google.com,
	keescook@chromium.org, ilias.apalodimas@linaro.org,
	alobakin@pm.me, memxor@gmail.com, atenart@kernel.org,
	bigeasy@linutronix.de, pabeni@redhat.com, linyunsheng@huawei.com,
	arnd@arndb.de, yajun.deng@linux.dev, roopa@nvidia.com,
	willemb@google.com, vvs@virtuozzo.com, cong.wang@bytedance.com,
	luiz.von.dentz@intel.com, linux-kernel@vger.kernel.org,
	netdev@vger.kernel.org, bpf@vger.kernel.org,
	flyingpeng@tencent.com
Subject: [PATCH net-next 03/19] net: tcp: use kfree_skb_reason() for tcp_v6_rcv()
Date: Tue, 15 Feb 2022 19:27:56 +0800	[thread overview]
Message-ID: <20220215112812.2093852-4-imagedong@tencent.com> (raw)
In-Reply-To: <20220215112812.2093852-1-imagedong@tencent.com>

From: Menglong Dong <imagedong@tencent.com>

Replace kfree_skb() used in tcp_v6_rcv() with kfree_skb_reason().

Signed-off-by: Menglong Dong <imagedong@tencent.com>
---
 net/ipv6/tcp_ipv6.c | 25 ++++++++++++++++++++-----
 1 file changed, 20 insertions(+), 5 deletions(-)

diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 0c648bf07f39..402ffbacc371 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1627,6 +1627,7 @@ static void tcp_v6_fill_cb(struct sk_buff *skb, const struct ipv6hdr *hdr,
 
 INDIRECT_CALLABLE_SCOPE int tcp_v6_rcv(struct sk_buff *skb)
 {
+	enum skb_drop_reason drop_reason;
 	int sdif = inet6_sdif(skb);
 	int dif = inet6_iif(skb);
 	const struct tcphdr *th;
@@ -1636,6 +1637,7 @@ INDIRECT_CALLABLE_SCOPE int tcp_v6_rcv(struct sk_buff *skb)
 	int ret;
 	struct net *net = dev_net(skb->dev);
 
+	drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;
 	if (skb->pkt_type != PACKET_HOST)
 		goto discard_it;
 
@@ -1649,8 +1651,10 @@ INDIRECT_CALLABLE_SCOPE int tcp_v6_rcv(struct sk_buff *skb)
 
 	th = (const struct tcphdr *)skb->data;
 
-	if (unlikely(th->doff < sizeof(struct tcphdr)/4))
+	if (unlikely(th->doff < sizeof(struct tcphdr) / 4)) {
+		drop_reason = SKB_DROP_REASON_PKT_TOO_SMALL;
 		goto bad_packet;
+	}
 	if (!pskb_may_pull(skb, th->doff*4))
 		goto discard_it;
 
@@ -1706,6 +1710,8 @@ INDIRECT_CALLABLE_SCOPE int tcp_v6_rcv(struct sk_buff *skb)
 			hdr = ipv6_hdr(skb);
 			tcp_v6_fill_cb(skb, hdr, th);
 			nsk = tcp_check_req(sk, skb, req, false, &req_stolen);
+		} else {
+			drop_reason = SKB_DROP_REASON_SOCKET_FILTER;
 		}
 		if (!nsk) {
 			reqsk_put(req);
@@ -1741,14 +1747,18 @@ INDIRECT_CALLABLE_SCOPE int tcp_v6_rcv(struct sk_buff *skb)
 		}
 	}
 
-	if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
+	if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb)) {
+		drop_reason = SKB_DROP_REASON_XFRM_POLICY;
 		goto discard_and_relse;
+	}
 
 	if (tcp_v6_inbound_md5_hash(sk, skb, dif, sdif))
 		goto discard_and_relse;
 
-	if (tcp_filter(sk, skb))
+	if (tcp_filter(sk, skb)) {
+		drop_reason = SKB_DROP_REASON_SOCKET_FILTER;
 		goto discard_and_relse;
+	}
 	th = (const struct tcphdr *)skb->data;
 	hdr = ipv6_hdr(skb);
 	tcp_v6_fill_cb(skb, hdr, th);
@@ -1779,13 +1789,17 @@ INDIRECT_CALLABLE_SCOPE int tcp_v6_rcv(struct sk_buff *skb)
 	return ret ? -1 : 0;
 
 no_tcp_socket:
-	if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
+	drop_reason = SKB_DROP_REASON_NO_SOCKET;
+	if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
+		drop_reason = SKB_DROP_REASON_XFRM_POLICY;
 		goto discard_it;
+	}
 
 	tcp_v6_fill_cb(skb, hdr, th);
 
 	if (tcp_checksum_complete(skb)) {
 csum_error:
+		drop_reason = SKB_DROP_REASON_TCP_CSUM;
 		trace_tcp_bad_csum(skb);
 		__TCP_INC_STATS(net, TCP_MIB_CSUMERRORS);
 bad_packet:
@@ -1795,7 +1809,7 @@ INDIRECT_CALLABLE_SCOPE int tcp_v6_rcv(struct sk_buff *skb)
 	}
 
 discard_it:
-	kfree_skb(skb);
+	kfree_skb_reason(skb, drop_reason);
 	return 0;
 
 discard_and_relse:
@@ -1806,6 +1820,7 @@ INDIRECT_CALLABLE_SCOPE int tcp_v6_rcv(struct sk_buff *skb)
 
 do_time_wait:
 	if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
+		drop_reason = SKB_DROP_REASON_XFRM_POLICY;
 		inet_twsk_put(inet_twsk(sk));
 		goto discard_it;
 	}
-- 
2.34.1

