Re: [PATCH] tcp: Export to userspace the TCP state names for the trace events

[Song Liu]

> On Nov 9, 2017, at 4:57 PM, Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
> 
> 
> From: "Steven Rostedt (VMware)" <rostedt@xxxxxxxxxxx>
> 
> The TCP trace events (specifically tcp_set_state), maps emums to symbol
> names via __print_symbolic(). But this only works for reading trace events
> from the tracefs trace files. If perf or trace-cmd were to record these
> events, the event format file does not convert the enum names into numbers,
> and you get something like:
> 
> __print_symbolic(REC->oldstate,
>    { TCP_ESTABLISHED, "TCP_ESTABLISHED" },
>    { TCP_SYN_SENT, "TCP_SYN_SENT" },
>    { TCP_SYN_RECV, "TCP_SYN_RECV" },
>    { TCP_FIN_WAIT1, "TCP_FIN_WAIT1" },
>    { TCP_FIN_WAIT2, "TCP_FIN_WAIT2" },
>    { TCP_TIME_WAIT, "TCP_TIME_WAIT" },
>    { TCP_CLOSE, "TCP_CLOSE" },
>    { TCP_CLOSE_WAIT, "TCP_CLOSE_WAIT" },
>    { TCP_LAST_ACK, "TCP_LAST_ACK" },
>    { TCP_LISTEN, "TCP_LISTEN" },
>    { TCP_CLOSING, "TCP_CLOSING" },
>    { TCP_NEW_SYN_RECV, "TCP_NEW_SYN_RECV" })
> 
> Where trace-cmd and perf do not know the values of those enums.
> 
> Use the TRACE_DEFINE_ENUM() macros that will have the trace events convert
> the enum strings into their values at system boot. This will allow perf and
> trace-cmd to see actual numbers and not enums:
> 
> __print_symbolic(REC->oldstate,
>    { 1, "TCP_ESTABLISHED" },
>    { 2, "TCP_SYN_SENT" },
>    { 3, "TCP_SYN_RECV" },
>    { 4, "TCP_FIN_WAIT1" },
>    { 5, "TCP_FIN_WAIT2" },
>    { 6, "TCP_TIME_WAIT" },
>    { 7, "TCP_CLOSE" },
>    { 8, "TCP_CLOSE_WAIT" },
>    { 9, "TCP_LAST_ACK" },
>    { 10, "TCP_LISTEN" },
>    { 11, "TCP_CLOSING" },
>    { 12, "TCP_NEW_SYN_RECV" })
> 
> Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
> ---
> include/trace/events/tcp.h | 41 ++++++++++++++++++++++++++++-------------
> 1 file changed, 28 insertions(+), 13 deletions(-)
> 
> diff --git a/include/trace/events/tcp.h b/include/trace/events/tcp.h
> index 07cccca6cbf1..62e5bad7901f 100644
> --- a/include/trace/events/tcp.h
> +++ b/include/trace/events/tcp.h
> @@ -9,21 +9,36 @@
> #include <linux/tracepoint.h>
> #include <net/ipv6.h>
> 
> +#define tcp_state_names				\
> +	EM(TCP_ESTABLISHED)			\
> +	EM(TCP_SYN_SENT)			\
> +	EM(TCP_SYN_RECV)			\
> +	EM(TCP_FIN_WAIT1)			\
> +	EM(TCP_FIN_WAIT2)			\
> +	EM(TCP_TIME_WAIT)			\
> +	EM(TCP_CLOSE)				\
> +	EM(TCP_CLOSE_WAIT)			\
> +	EM(TCP_LAST_ACK)			\
> +	EM(TCP_LISTEN)				\
> +	EM(TCP_CLOSING)				\
> +	EMe(TCP_NEW_SYN_RECV)
> +
> +/* enums need to be exported to user space */
> +#undef EM
> +#undef EMe
> +#define EM(a)         TRACE_DEFINE_ENUM(a);
> +#define EMe(a)        TRACE_DEFINE_ENUM(a);
> +
> +tcp_state_names
> +
> +#undef EM
> +#undef EMe
> +#define EM(a)         tcp_state_name(a),
> +#define EMe(a)        tcp_state_name(a)
> +
> #define tcp_state_name(state)	{ state, #state }
> #define show_tcp_state_name(val)			\
> -	__print_symbolic(val,				\
> -		tcp_state_name(TCP_ESTABLISHED),	\
> -		tcp_state_name(TCP_SYN_SENT),		\
> -		tcp_state_name(TCP_SYN_RECV),		\
> -		tcp_state_name(TCP_FIN_WAIT1),		\
> -		tcp_state_name(TCP_FIN_WAIT2),		\
> -		tcp_state_name(TCP_TIME_WAIT),		\
> -		tcp_state_name(TCP_CLOSE),		\
> -		tcp_state_name(TCP_CLOSE_WAIT),		\
> -		tcp_state_name(TCP_LAST_ACK),		\
> -		tcp_state_name(TCP_LISTEN),		\
> -		tcp_state_name(TCP_CLOSING),		\
> -		tcp_state_name(TCP_NEW_SYN_RECV))
> +	__print_symbolic(val, tcp_state_names)
> 
> /*
>  * tcp event with arguments sk and skb
> -- 
> 2.13.6
> 

Reviewed-and-tested-by: Song Liu <songliubraving@xxxxxx>