[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, 27 insertions, 0 deletions

diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c
index 48c36afa4934..fe4cc85f5bcc 100644
--- a/net/dccp/ccids/ccid3.c
+++ b/net/dccp/ccids/ccid3.c
@@ -2020,6 +2020,31 @@ static void ccid3_hc_rx_exit(struct sock *sk)
         dp->dccps_hc_rx_ccid_private = NULL;
 }
 
+static void ccid3_hc_rx_get_info(struct sock *sk, struct tcp_info *info)
+{
+        const struct dccp_sock *dp = dccp_sk(sk);
+        const struct ccid3_hc_rx_sock *hcrx = dp->dccps_hc_rx_ccid_private;
+
+        if (hcrx == NULL)
+                return;
+
+        info->tcpi_ca_state     = hcrx->ccid3hcrx_state;
+        info->tcpi_options      |= TCPI_OPT_TIMESTAMPS;
+        info->tcpi_rcv_rtt      = hcrx->ccid3hcrx_rtt;
+}
+
+static void ccid3_hc_tx_get_info(struct sock *sk, struct tcp_info *info)
+{
+        const struct dccp_sock *dp = dccp_sk(sk);
+        const struct ccid3_hc_tx_sock *hctx = dp->dccps_hc_tx_ccid_private;
+
+        if (hctx == NULL)
+                return;
+
+        info->tcpi_rto = hctx->ccid3hctx_t_rto;
+        info->tcpi_rtt = hctx->ccid3hctx_rtt;
+}
+
 static struct ccid ccid3 = {
         .ccid_id                   = 3,
         .ccid_name                 = "ccid3",
@@ -2037,6 +2062,8 @@ static struct ccid ccid3 = {
         .ccid_hc_rx_exit           = ccid3_hc_rx_exit,
         .ccid_hc_rx_insert_options = ccid3_hc_rx_insert_options,
         .ccid_hc_rx_packet_recv    = ccid3_hc_rx_packet_recv,
+        .ccid_hc_rx_get_info       = ccid3_hc_rx_get_info,
+        .ccid_hc_tx_get_info       = ccid3_hc_tx_get_info,
 };
  
 module_param(ccid3_debug, int, 0444);