[MPTCP][PATCH mptcp-next 6/6] mptcp: add trace event for DSS checksum

[Geliang Tang <geliangtang@gmail.com>]

This patch added the trace event for DSS checksum. Add a tracepoint in
mptcp_generate_dss_csum and a tracepoint in validate_dss_csum.

Signed-off-by: Geliang Tang <geliangtang@gmail.com>
---
 include/trace/events/mptcp.h | 51 ++++++++++++++++++++++++++++++++++++
 net/mptcp/options.c          |  4 +++
 net/mptcp/protocol.c         |  3 +++
 net/mptcp/subflow.c          |  4 +++
 4 files changed, 62 insertions(+)
 create mode 100644 include/trace/events/mptcp.h

diff --git a/include/trace/events/mptcp.h b/include/trace/events/mptcp.h
new file mode 100644
index 000000000000..a5b87e304303
--- /dev/null
+++ b/include/trace/events/mptcp.h
@@ -0,0 +1,51 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM mptcp
+
+#if !defined(_TRACE_MPTCP_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_MPTCP_H
+
+#include <linux/tracepoint.h>
+
+DECLARE_EVENT_CLASS(mptcp_event_dss_csum,
+
+	TP_PROTO(struct csum_pseudo_header *header, __u16 csum),
+
+	TP_ARGS(header, csum),
+
+	TP_STRUCT__entry(
+		__field(__u64, data_seq)
+		__field(__u32, subflow_seq)
+		__field(__u16, data_len)
+		__field(__u16, dss_csum)
+		__field(__u16, csum)
+	),
+
+	TP_fast_assign(
+		__entry->data_seq = header->data_seq;
+		__entry->subflow_seq = header->subflow_seq;
+		__entry->data_len = header->data_len;
+		__entry->dss_csum = header->csum;
+		__entry->csum = csum;
+	),
+
+	TP_printk("data_seq=%llu subflow_seq=%u data_len=%u csum=%u",
+		  __entry->data_seq, __entry->subflow_seq, __entry->data_len,
+		  __entry->csum)
+);
+
+DEFINE_EVENT(mptcp_event_dss_csum, mptcp_generate_dss_csum,
+	TP_PROTO(struct csum_pseudo_header *header, __u16 csum),
+	TP_ARGS(header, csum));
+
+DEFINE_EVENT_PRINT(mptcp_event_dss_csum, validate_dss_csum,
+	TP_PROTO(struct csum_pseudo_header *header, __u16 csum),
+	TP_ARGS(header, csum),
+	TP_printk("data_seq=%llu subflow_seq=%u data_len=%u csum=%u, DSS checksum %s!",
+		  __entry->data_seq, __entry->subflow_seq, __entry->data_len,
+		  __entry->dss_csum, __entry->csum ? "error" : "done"));
+
+#endif /* _TRACE_MPTCP_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index ed89f6c2ed49..8ec41bf56c3b 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -13,6 +13,8 @@
 #include "protocol.h"
 #include "mib.h"
 
+#include <trace/events/mptcp.h>
+
 static bool mptcp_cap_flag_sha256(u8 flags)
 {
 	return (flags & MPTCP_CAP_FLAG_MASK) == MPTCP_CAP_HMAC_SHA256;
@@ -548,6 +550,8 @@ static u16 mptcp_generate_dss_csum(struct sk_buff *skb)
 	csum = skb_checksum(skb, 0, skb->len, 0);
 	csum = csum_partial(&header, sizeof(header), csum);
 
+	trace_mptcp_generate_dss_csum(&header, csum_fold(csum));
+
 	return csum_fold(csum);
 }
 
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 94c3568c7a60..1f767612c917 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -25,6 +25,9 @@
 #include "protocol.h"
 #include "mib.h"
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/mptcp.h>
+
 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
 struct mptcp6_sock {
 	struct mptcp_sock msk;
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 2eeea7d527f0..7e63d902a3de 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -27,6 +27,8 @@
 
 static void mptcp_subflow_ops_undo_override(struct sock *ssk);
 
+#include <trace/events/mptcp.h>
+
 static void SUBFLOW_REQ_INC_STATS(struct request_sock *req,
 				  enum linux_mptcp_mib_field field)
 {
@@ -821,6 +823,8 @@ static bool validate_dss_csum(struct sock *ssk, struct sk_buff *skb)
 	csum = skb_checksum(skb, 0, skb->len, 0);
 	csum = csum_partial(&header, sizeof(header), csum);
 
+	trace_validate_dss_csum(&header, csum_fold(csum));
+
 	if (csum_fold(csum)) {
 		pr_err("DSS checksum error! data_seq=%llu subflow_seq=%u data_len=%u csum=%u %u",
 		       header.data_seq, header.subflow_seq, header.data_len,
-- 
2.30.2