tcp: use data length instead of skb->len in tcp_probe

skb->len is meaningless to user.
data length could be more helpful, with which we can easily filter out
the packet without payload.

Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/trace/events/tcp.h b/include/trace/events/tcp.h
index c1a5284..703abb6 100644 (file)
--- a/include/trace/events/tcp.h
+++ b/include/trace/events/tcp.h
@@ -236,7 +236,7 @@ TRACE_EVENT(tcp_probe,
                __field(__u16, sport)
                __field(__u16, dport)
                __field(__u32, mark)
-               __field(__u16, length)
+               __field(__u16, data_len)
                __field(__u32, snd_nxt)
                __field(__u32, snd_una)
                __field(__u32, snd_cwnd)
@@ -261,7 +261,7 @@ TRACE_EVENT(tcp_probe,
                __entry->dport = ntohs(inet->inet_dport);
                __entry->mark = skb->mark;
 
-               __entry->length = skb->len;
+               __entry->data_len = skb->len - tcp_hdrlen(skb);
                __entry->snd_nxt = tp->snd_nxt;
                __entry->snd_una = tp->snd_una;
                __entry->snd_cwnd = tp->snd_cwnd;
@@ -272,9 +272,9 @@ TRACE_EVENT(tcp_probe,
                __entry->sock_cookie = sock_gen_cookie(sk);
        ),
 
-       TP_printk("src=%pISpc dest=%pISpc mark=%#x length=%d snd_nxt=%#x snd_una=%#x snd_cwnd=%u ssthresh=%u snd_wnd=%u srtt=%u rcv_wnd=%u sock_cookie=%llx",
+       TP_printk("src=%pISpc dest=%pISpc mark=%#x data_len=%d snd_nxt=%#x snd_una=%#x snd_cwnd=%u ssthresh=%u snd_wnd=%u srtt=%u rcv_wnd=%u sock_cookie=%llx",
                  __entry->saddr, __entry->daddr, __entry->mark,
-                 __entry->length, __entry->snd_nxt, __entry->snd_una,
+                 __entry->data_len, __entry->snd_nxt, __entry->snd_una,
                  __entry->snd_cwnd, __entry->ssthresh, __entry->snd_wnd,
                  __entry->srtt, __entry->rcv_wnd, __entry->sock_cookie)
 );