Re: [Patch net-next 02/13] ipv4: introduce tracepoint trace_ip_queue_xmit()

From: Qitao Xu <redacted>

Tracepoint trace_ip_queue_xmit() is introduced to trace skb
at the entrance of IP layer on TX side.

Reviewed-by: Cong Wang <redacted>
Signed-off-by: Qitao Xu <redacted>
---
 include/trace/events/ip.h | 42 +++++++++++++++++++++++++++++++++++++++
 net/ipv4/ip_output.c      | 10 +++++++++-
 2 files changed, 51 insertions(+), 1 deletion(-)

diff --git a/include/trace/events/ip.h b/include/trace/events/ip.h
index 008f821ebc50..553ae7276732 100644
--- a/include/trace/events/ip.h
+++ b/include/trace/events/ip.h

@@ -41,6 +41,48 @@
 	TP_STORE_V4MAPPED(__entry, saddr, daddr)
 #endif
 
+TRACE_EVENT(ip_queue_xmit,
+
+	TP_PROTO(const struct sock *sk, const struct sk_buff *skb),
+
+	TP_ARGS(sk, skb),
+
+	TP_STRUCT__entry(
+		__field(const void *, skbaddr)
+		__field(const void *, skaddr)
+		__field(__u16, sport)
+		__field(__u16, dport)
+		__array(__u8, saddr, 4)
+		__array(__u8, daddr, 4)
+		__array(__u8, saddr_v6, 16)
+		__array(__u8, daddr_v6, 16)
+	),
+
+	TP_fast_assign(
+		struct inet_sock *inet = inet_sk(sk);
+		__be32 *p32;
+
+		__entry->skbaddr = skb;
+		__entry->skaddr = sk;
+
+		__entry->sport = ntohs(inet->inet_sport);
+		__entry->dport = ntohs(inet->inet_dport);
+
+		p32 = (__be32 *) __entry->saddr;
+		*p32 = inet->inet_saddr;
+
+		p32 = (__be32 *) __entry->daddr;
+		*p32 =  inet->inet_daddr;
+
+		TP_STORE_ADDRS(__entry, inet->inet_saddr, inet->inet_daddr,
+			      sk->sk_v6_rcv_saddr, sk->sk_v6_daddr);
+	),
+
+	TP_printk("sport=%hu dport=%hu saddr=%pI4 daddr=%pI4 saddrv6=%pI6c daddrv6=%pI6c skbaddr=%px",
+		  __entry->sport, __entry->dport, __entry->saddr, __entry->daddr,
+		  __entry->saddr_v6, __entry->daddr_v6, __entry->skbaddr)
+);
+
 #endif /* _TRACE_IP_H */
 
 /* This part must be outside protection */

diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index 6b04a88466b2..dcf94059112e 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c

@@ -82,6 +82,7 @@
 #include <linux/netfilter_bridge.h>
 #include <linux/netlink.h>
 #include <linux/tcp.h>
+#include <trace/events/ip.h>
 
 static int
 ip_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,

@@ -536,7 +537,14 @@ EXPORT_SYMBOL(__ip_queue_xmit);
 
 int ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl)
 {
-	return __ip_queue_xmit(sk, skb, fl, inet_sk(sk)->tos);
+	int ret;
+
+	ret = __ip_queue_xmit(sk, skb, fl, inet_sk(sk)->tos);
+	if (!ret)
+		trace_ip_queue_xmit(sk, skb);