[DCCP]: Introduce dccp_get_info

And also hc_tx and hc_rx get_info functions for the CCIDs to fill in
information that is specific to them.

For now reusing struct tcp_info, later I'll try to figure out a better
solution, for now its really nice to get this kind of info:

[root@qemu ~]# ./ss -danemi
State       Recv-Q Send-Q  Local Addr:Port  Peer Addr:Port
LISTEN      0      0                *:5001          *:*     ino:628 sk:c1340040
         mem:(r0,w0,f0,t0) cwnd:0 ssthresh:0
ESTAB       0      0       172.20.0.2:5001 172.20.0.1:32785 ino:629 sk:c13409a0
         mem:(r0,w0,f0,t0) ts rto:1000 rtt:0.004/0 cwnd:0 ssthresh:0 rcv_rtt:61.377

This, for instance, shows that we're not congestion controlling ACKs,
as the above output is in the ttcp receiving host, and ttcp is a one
way app, i.e. the received never calls sendmsg, so
ccid_hc_tx_send_packet is never called, so the TX half connection
stays in TFRC_SSTATE_NO_SENT state and hctx_rtt is never calculated,
stays with the value set in ccid3_hc_tx_init, 4us, as show above in
milliseconds (0.004ms), upcoming patches will fix this.

rcv_rtt seems sane tho, matching ping results :-)

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 18 insertions, 0 deletions

diff --git a/net/dccp/ccid.h b/net/dccp/ccid.h
index c6767b282244..962f1e9e2f7e 100644
--- a/net/dccp/ccid.h
+++ b/net/dccp/ccid.h
@@ -50,6 +50,10 @@ struct ccid {
                                                   struct sk_buff *skb, int len);
         void            (*ccid_hc_tx_packet_sent)(struct sock *sk, int more,
                                                   int len);
+        void            (*ccid_hc_rx_get_info)(struct sock *sk,
+                                               struct tcp_info *info);
+        void            (*ccid_hc_tx_get_info)(struct sock *sk,
+                                               struct tcp_info *info);
 };
 
 extern int         ccid_register(struct ccid *ccid);
@@ -159,4 +163,18 @@ static inline void ccid_hc_rx_insert_options(struct ccid *ccid, struct sock *sk,
         if (ccid->ccid_hc_rx_insert_options != NULL)
                 ccid->ccid_hc_rx_insert_options(sk, skb);
 }
+
+static inline void ccid_hc_rx_get_info(struct ccid *ccid, struct sock *sk,
+                                       struct tcp_info *info)
+{
+        if (ccid->ccid_hc_rx_get_info != NULL)
+                ccid->ccid_hc_rx_get_info(sk, info);
+}
+
+static inline void ccid_hc_tx_get_info(struct ccid *ccid, struct sock *sk,
+                                       struct tcp_info *info)
+{
+        if (ccid->ccid_hc_tx_get_info != NULL)
+                ccid->ccid_hc_tx_get_info(sk, info);
+}
 #endif /* _CCID_H */