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

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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>
This commit is contained in:
Gerrit Renker
2009-01-16 23:36:31 +00:00
committed by David S. Miller
parent f90f92eed7
commit 792b48780e
6 changed files with 24 additions and 45 deletions
Download Patch File Download Diff File Expand all files Collapse all files
net/dccp/dccp.h
+7 -9
View File
@@ -409,23 +409,21 @@ static inline void dccp_hdr_set_ack(struct dccp_hdr_ack_bits *dhack,
static inline void dccp_update_gsr(struct sock *sk, u64 seq)
{
struct dccp_sock *dp = dccp_sk(sk);
const struct dccp_minisock *dmsk = dccp_msk(sk);
dp->dccps_gsr = seq;
dccp_set_seqno(&dp->dccps_swl,
dp->dccps_gsr + 1 - (dmsk->dccpms_sequence_window / 4));
dccp_set_seqno(&dp->dccps_swh,
dp->dccps_gsr + (3 * dmsk->dccpms_sequence_window) / 4);
/* Sequence validity window depends on remote Sequence Window (7.5.1) */
dp->dccps_swl = SUB48(ADD48(dp->dccps_gsr, 1), dp->dccps_r_seq_win / 4);
dp->dccps_swh = ADD48(dp->dccps_gsr, (3 * dp->dccps_r_seq_win) / 4);
}
static inline void dccp_update_gss(struct sock *sk, u64 seq)
{
struct dccp_sock *dp = dccp_sk(sk);
dp->dccps_awh = dp->dccps_gss = seq;
dccp_set_seqno(&dp->dccps_awl,
(dp->dccps_gss -
dccp_msk(sk)->dccpms_sequence_window + 1));
dp->dccps_gss = seq;
/* Ack validity window depends on local Sequence Window value (7.5.1) */
dp->dccps_awl = SUB48(ADD48(dp->dccps_gss, 1), dp->dccps_l_seq_win);
dp->dccps_awh = dp->dccps_gss;
}
static inline int dccp_ack_pending(const struct sock *sk)