dccp: Implement both feature-local and feature-remote Sequence Window feature

This adds full support for local/remote Sequence Window feature, from which the
  * sequence-number-validity (W) and
  * acknowledgment-number-validity (W') windows
derive as specified in RFC 4340, 7.5.3.

Specifically, the following is contained in this patch:
  * integrated new socket fields into dccp_sk;
  * updated the update_gsr/gss routines with regard to these fields;
  * updated handler code: the Sequence Window feature is located at the TX side,
    so the local feature is meant if the handler-rx flag is false;
  * the initialisation of `rcv_wnd' in reqsk is removed, since
    - rcv_wnd is not used by the code anywhere;
    - sequence number checks are not done in the LISTEN state (cf. 7.5.3);
    - dccp_check_req checks the Ack number validity more rigorously;
  * the `struct dccp_minisock' became empty and is now removed.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 0 insertions, 2 deletions

diff --git a/net/dccp/proto.c b/net/dccp/proto.c
index 945b4d5d23b3..314a1b5c033c 100644
--- a/net/dccp/proto.c
+++ b/net/dccp/proto.c
@@ -174,8 +174,6 @@ int dccp_init_sock(struct sock *sk, const __u8 ctl_sock_initialized)
         struct dccp_sock *dp = dccp_sk(sk);
         struct inet_connection_sock *icsk = inet_csk(sk);
 
-        dccp_minisock_init(&dp->dccps_minisock);
-
         icsk->icsk_rto          = DCCP_TIMEOUT_INIT;
         icsk->icsk_syn_retries  = sysctl_dccp_request_retries;
         sk->sk_state            = DCCP_CLOSED;