07 Jun, 2011

1 commit


21 Jan, 2011

1 commit


07 Dec, 2010

1 commit

  • This patch adds a generic infrastructure for policy-based dequeueing of
    TX packets and provides two policies:
    * a simple FIFO policy (which is the default) and
    * a priority based policy (set via socket options).
    Both policies honour the tx_qlen sysctl for the maximum size of the write
    queue (can be overridden via socket options).

    The priority policy uses skb->priority internally to assign an u32 priority
    identifier, using the same ranking as SO_PRIORITY. The skb->priority field
    is set to 0 when the packet leaves DCCP. The priority is supplied as ancillary
    data using cmsg(3), the patch also provides the requisite parsing routines.

    Signed-off-by: Tomasz Grobelny
    Signed-off-by: Gerrit Renker

    Tomasz Grobelny
     

15 Nov, 2010

1 commit

  • The problem with Ack Vectors is that
    i) their length is variable and can in principle grow quite large,
    ii) it is hard to predict exactly how large they will be.

    Due to the second point it seems not a good idea to reduce the MPS; in
    particular when on average there is enough room for the Ack Vector and an
    increase in length is momentarily due to some burst loss, after which the
    Ack Vector returns to its normal/average length.

    The solution taken by this patch is to subtract a minimum-expected Ack Vector
    length from the MPS, and to defer any larger Ack Vectors onto a separate
    Sync - but only if indeed there is no space left on the skb.

    This patch provides the infrastructure to schedule Sync-packets for transporting
    (urgent) out-of-band data. Its signalling is quicker than scheduling an Ack, since
    it does not need to wait for new application data.

    Signed-off-by: Gerrit Renker

    Gerrit Renker
     

29 Oct, 2010

1 commit

  • This extends the packet dequeuing interface of dccp_write_xmit() to allow
    1. CCIDs to take care of timing when the next packet may be sent;
    2. delayed sending (as before, with an inter-packet gap up to 65.535 seconds).

    The main purpose is to take CCID-2 out of its polling mode (when it is network-
    limited, it tries every millisecond to send, without interruption).

    The mode of operation for (2) is as follows:
    * new packet is enqueued via dccp_sendmsg() => dccp_write_xmit(),
    * ccid_hc_tx_send_packet() detects that it may not send (e.g. window full),
    * it signals this condition via `CCID_PACKET_WILL_DEQUEUE_LATER',
    * dccp_write_xmit() returns without further action;
    * after some time the wait-condition for CCID becomes true,
    * that CCID schedules the tasklet,
    * tasklet function calls ccid_hc_tx_send_packet() via dccp_write_xmit(),
    * since the wait-condition is now true, ccid_hc_tx_packet() returns "send now",
    * packet is sent, and possibly more (since dccp_write_xmit() loops).

    Code reuse: the taskled function calls dccp_write_xmit(), the timer function
    reduces to a wrapper around the same code.

    Signed-off-by: Gerrit Renker
    Signed-off-by: David S. Miller

    Gerrit Renker
     

21 Sep, 2010

1 commit


22 Jan, 2009

3 commits

  • This patch takes care of initialising and type-checking sysctls
    related to feature negotiation. Type checking is important since some
    of the sysctls now directly impact the feature-negotiation process.

    The sysctls are initialised with the known default values for each
    feature. For the type-checking the value constraints from RFC 4340
    are used:

    * Sequence Window uses the specified Wmin=32, the maximum is ulong (4 bytes),
    tested and confirmed that it works up to 4294967295 - for Gbps speed;
    * Ack Ratio is between 0 .. 0xffff (2-byte unsigned integer);
    * CCIDs are between 0 .. 255;
    * request_retries, retries1, retries2 also between 0..255 for good measure;
    * tx_qlen is checked to be non-negative;
    * sync_ratelimit remains as before.

    Notes:
    ------
    1. Die s@sysctl_dccp_feat@sysctl_dccp@g since the sysctls are now in feat.c.
    2. As pointed out by Arnaldo, the pattern of type-checking repeats itself in
    other places, sometimes with exactly the same kind of definitions (e.g.
    "static int zero;"). It may be a good idea (kernel janitors?) to consolidate
    type checking. For the sake of keeping the changeset small and in order not
    to affect other subsystems, I have not strived to generalise here.

    Signed-off-by: Gerrit Renker
    Acked-by: Ian McDonald
    Signed-off-by: David S. Miller

    Gerrit Renker
     
  • 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
    Acked-by: Ian McDonald
    Signed-off-by: David S. Miller

    Gerrit Renker
     
  • This initialises feature negotiation from two tables, which are in
    turn are initialised from sysctls.

    As a novel feature, specifics of the implementation (e.g. that short
    seqnos and ECN are not yet available) are advertised for robustness.

    Signed-off-by: Gerrit Renker
    Acked-by: Ian McDonald
    Signed-off-by: David S. Miller

    Gerrit Renker
     

08 Dec, 2008

3 commits

  • This removes the use of the sysctl and the minisock variable for the Send Ack
    Vector feature, as it now is handled fully dynamically via feature negotiation
    (i.e. when CCID-2 is enabled, Ack Vectors are automatically enabled as per
    RFC 4341, 4.).

    Using a sysctl in parallel to this implementation would open the door to
    crashes, since much of the code relies on tests of the boolean minisock /
    sysctl variable. Thus, this patch replaces all tests of type

    if (dccp_msk(sk)->dccpms_send_ack_vector)
    /* ... */
    with
    if (dp->dccps_hc_rx_ackvec != NULL)
    /* ... */

    The dccps_hc_rx_ackvec is allocated by the dccp_hdlr_ackvec() when feature
    negotiation concluded that Ack Vectors are to be used on the half-connection.
    Otherwise, it is NULL (due to dccp_init_sock/dccp_create_openreq_child),
    so that the test is a valid one.

    The activation handler for Ack Vectors is called as soon as the feature
    negotiation has concluded at the
    * server when the Ack marking the transition RESPOND => OPEN arrives;
    * client after it has sent its ACK, marking the transition REQUEST => PARTOPEN.

    Adding the sequence number of the Response packet to the Ack Vector has been
    removed, since
    (a) connection establishment implies that the Response has been received;
    (b) the CCIDs only look at packets received in the (PART)OPEN state, i.e.
    this entry will always be ignored;
    (c) it can not be used for anything useful - to detect loss for instance, only
    packets received after the loss can serve as pseudo-dupacks.

    There was a FIXME to change the error code when dccp_ackvec_add() fails.
    I removed this after finding out that:
    * the check whether ackno < ISN is already made earlier,
    * this Response is likely the 1st packet with an Ackno that the client gets,
    * so when dccp_ackvec_add() fails, the reason is likely not a packet error.

    Signed-off-by: Gerrit Renker
    Acked-by: Ian McDonald
    Signed-off-by: David S. Miller

    Gerrit Renker
     
  • Updating the NDP count feature is handled automatically now:
    * for CCID-2 it is disabled, since the code does not use NDP counts;
    * for CCID-3 it is enabled, as NDP counts are used to determine loss lengths.

    Allowing the user to change NDP values leads to unpredictable and failing
    behaviour, since it is then possible to disable NDP counts even when they
    are needed (e.g. in CCID-3).

    This means that only those user settings are sensible that agree with the
    values for Send NDP Count implied by the choice of CCID. But those settings
    are already activated by the feature negotiation (CCID dependency tracking),
    hence this form of support is redundant.

    At startup the initialisation of the NDP count feature uses the default
    value of 0, which is done implicitly by the zeroing-out of the socket when
    it is allocated. If the choice of CCID or feature negotiation enables NDP
    count, this will then be updated via the NDP activation handler.

    Signed-off-by: Gerrit Renker
    Acked-by: Ian McDonald
    Signed-off-by: David S. Miller

    Gerrit Renker
     
  • The TX/RX CCIDs of the minisock are now redundant: similar to the Ack Vector
    case, their value equals initially that of the sysctl, but at the end of
    feature negotiation may be something different.

    The old interface removed by this patch thus has been replaced by the newer
    interface to dynamically query the currently loaded CCIDs.

    Also removed are the constructors for the TX CCID and the RX CCID, since the
    switch "rx non-rx" is done by the handler in minisocks.c (and the handler
    is the only place in the code where CCIDs are loaded).

    Signed-off-by: Gerrit Renker
    Acked-by: Ian McDonald
    Signed-off-by: David S. Miller

    Gerrit Renker
     

24 Nov, 2008

1 commit

  • With this patch, TX/RX CCIDs can now be changed on a per-connection
    basis, which overrides the defaults set by the global sysctl variables
    for TX/RX CCIDs.

    To make full use of this facility, the remaining patches of this patch
    set are needed, which track dependencies and activate negotiated
    feature values.

    Signed-off-by: Gerrit Renker
    Signed-off-by: David S. Miller

    Gerrit Renker
     

17 Nov, 2008

3 commits

  • This patch deprecates the Ack Ratio sysctl, since
    * Ack Ratio is entirely ignored by CCID-3 and CCID-4,
    * Ack Ratio currently doesn't work in CCID-2 (i.e. is always set to 1);
    * even if it would work in CCID-2, there is no point for a user to change it:
    - Ack Ratio is constrained by cwnd (RFC 4341, 6.1.2),
    - if Ack Ratio > cwnd, the system resorts to spurious RTO timeouts
    (since waiting for Acks which will never arrive in this window),
    - cwnd is not a user-configurable value.

    The only reasonable place for Ack Ratio is to print it for debugging. It is
    planned to do this later on, as part of e.g. dccp_probe.

    With this patch Ack Ratio is now under full control of feature negotiation:
    * Ack Ratio is resolved as a dependency of the selected CCID;
    * if the chosen CCID supports it (i.e. CCID == CCID-2), Ack Ratio is set to
    the default of 2, following RFC 4340, 11.3 - "New connections start with Ack
    Ratio 2 for both endpoints";
    * what happens then is part of another patch set, since it concerns the
    dynamic update of Ack Ratio while the connection is in full flight.

    Thanks to Tomasz Grobelny for discussion leading up to this patch.

    Signed-off-by: Gerrit Renker
    Acked-by: Arnaldo Carvalho de Melo
    Signed-off-by: David S. Miller

    Gerrit Renker
     
  • This provides feature negotiation for server minimum checksum coverage
    which so far has been missing.

    Since sender/receiver coverage values range only from 0...15, their
    type has also been reduced in size from u16 to u4.

    Feature-negotiation options are now generated for both sender and receiver
    coverage, i.e. when the peer has `forgotten' to enable partial coverage
    then feature negotiation will automatically enable (negotiate) the partial
    coverage value for this connection.

    Signed-off-by: Gerrit Renker
    Acked-by: Ian McDonald
    Signed-off-by: David S. Miller

    Gerrit Renker
     
  • The previous setsockopt interface, which passed socket options via struct
    dccp_so_feat, is complicated/difficult to use. Continuing to support it leads to
    ugly code since the old approach did not distinguish between NN and SP values.

    This patch removes the old setsockopt interface and replaces it with two new
    functions to register NN/SP values for feature negotiation.
    These are essentially wrappers around the internal __feat_register functions,
    with checking added to avoid

    * wrong usage (type);
    * changing values while the connection is in progress.

    Signed-off-by: Gerrit Renker
    Signed-off-by: David S. Miller

    Gerrit Renker
     

12 Nov, 2008

1 commit

  • This provides a data structure to record which CCIDs are locally supported
    and three accessor functions:
    - a test function for internal use which is used to validate CCID requests
    made by the user;
    - a copy function so that the list can be used for feature-negotiation;
    - documented getsockopt() support so that the user can query capabilities.

    The data structure is a table which is filled in at compile-time with the
    list of available CCIDs (which in turn depends on the Kconfig choices).

    Using the copy function for cloning the list of supported CCIDs is useful for
    feature negotiation, since the negotiation is now with the full list of available
    CCIDs (e.g. {2, 3}) instead of the default value {2}. This means negotiation
    will not fail if the peer requests to use CCID3 instead of CCID2.

    Signed-off-by: Gerrit Renker
    Acked-by: Ian McDonald
    Signed-off-by: David S. Miller

    Gerrit Renker
     

05 Nov, 2008

2 commits

  • This provides feature-negotiation initialisation for both DCCP sockets
    and DCCP request_sockets, to support feature negotiation during
    connection setup.

    It also resolves a FIXME regarding the congestion control
    initialisation.

    Thanks to Wei Yongjun for help with the IPv6 side of this patch.

    Signed-off-by: Gerrit Renker
    Acked-by: Ian McDonald
    Signed-off-by: David S. Miller

    Gerrit Renker
     
  • A lookup table for feature-negotiation information, extracted from RFC
    4340/42, is provided by this patch. All currently known features can
    be found in this table, along with their feature location, their
    default value, and type.

    Signed-off-by: Gerrit Renker
    Acked-by: Ian McDonald
    Acked-by: Arnaldo Carvalho de Melo
    Signed-off-by: David S. Miller

    Gerrit Renker
     

13 Jul, 2008

1 commit


03 Feb, 2008

1 commit


29 Jan, 2008

6 commits

  • In DCCP, timestamps can occur on packets anytime, CCID3 uses a timestamp(/echo) on the Request/Response
    exchange. This patch addresses the following situation:
    * timestamps are recorded on the listening socket;
    * Responses are sent from dccp_request_sockets;
    * suppose two connections reach the listening socket with very small time in between:
    * the first timestamp value gets overwritten by the second connection request.

    This is not really good, so this patch separates timestamps into
    * those which are received by the server during the initial handshake (on dccp_request_sock);
    * those which are received by the client or the client after connection establishment.

    As before, a timestamp of 0 is regarded as indicating that no (meaningful) timestamp has been
    received (in addition, a warning message is printed if hosts send 0-valued timestamps).

    The timestamp-echoing now works as follows:
    * when a timestamp is present on the initial Request, it is placed into dreq, due to the
    call to dccp_parse_options in dccp_v{4,6}_conn_request;
    * when a timestamp is present on the Ack leading from RESPOND => OPEN, it is copied over
    from the request_sock into the child cocket in dccp_create_openreq_child;
    * timestamps received on an (established) dccp_sock are treated as before.

    Since Elapsed Time is measured in hundredths of milliseconds (13.2), the new dccp_timestamp()
    function is used, as it is expected that the time between receiving the timestamp and
    sending the timestamp echo will be very small against the wrap-around time. As a byproduct,
    this allows smaller timestamping-time fields.

    Furthermore, inserting the Timestamp Echo option has been taken out of the block starting with
    '!dccp_packet_without_ack()', since Timestamp Echo can be carried on any packet (5.8 and 13.3).

    Signed-off-by: Gerrit Renker
    Acked-by: Ian McDonald
    Signed-off-by: Arnaldo Carvalho de Melo
    Signed-off-by: David S. Miller

    Gerrit Renker
     
  • The option parsing code currently only parses on full sk's. This causes a problem for
    options sent during the initial handshake (in particular timestamps and feature-negotiation
    options). Therefore, this patch extends the option parsing code with an additional argument
    for request_socks: if it is non-NULL, options are parsed on the request socket, otherwise
    the normal path (parsing on the sk) is used.

    Subsequent patches, which implement feature negotiation during connection setup, make use
    of this facility.

    Signed-off-by: Gerrit Renker
    Signed-off-by: Ian McDonald
    Signed-off-by: Arnaldo Carvalho de Melo
    Signed-off-by: David S. Miller

    Gerrit Renker
     
  • This adds a socket option and signalling support for the case where the server
    holds timewait state on closing the connection, as described in RFC 4340, 8.3.

    Since holding timewait state at the server is the non-usual case, it is enabled
    via a socket option. Documentation for this socket option has been added.

    The setsockopt statement has been made resilient against different possible cases
    of expressing boolean `true' values using a suggestion by Ian McDonald.

    Signed-off-by: Gerrit Renker
    Signed-off-by: Ian McDonald
    Signed-off-by: Arnaldo Carvalho de Melo
    Signed-off-by: David S. Miller

    Gerrit Renker
     
  • This adds the necessary state transitions for the two forms of passive-close

    * PASSIVE_CLOSE - which is entered when a host receives a Close;
    * PASSIVE_CLOSEREQ - which is entered when a client receives a CloseReq.

    Here is a detailed account of what the patch does in each state.

    1) Receiving CloseReq

    The pseudo-code in 8.5 says:

    Step 13: Process CloseReq
    If P.type == CloseReq and S.state < CLOSEREQ,
    Generate Close
    S.state := CLOSING
    Set CLOSING timer.

    This means we need to address what to do in CLOSED, LISTEN, REQUEST, RESPOND, PARTOPEN, and OPEN.

    * CLOSED: silently ignore - it may be a late or duplicate CloseReq;
    * LISTEN/RESPOND: will not appear, since Step 7 is performed first (we know we are the client);
    * REQUEST: perform Step 13 directly (no need to enqueue packet);
    * OPEN/PARTOPEN: enter PASSIVE_CLOSEREQ so that the application has a chance to process unread data.

    When already in PASSIVE_CLOSEREQ, no second CloseReq is enqueued. In any other state, the CloseReq is ignored.
    I think that this offers some robustness against rare and pathological cases: e.g. a simultaneous close where
    the client sends a Close and the server a CloseReq. The client will then be retransmitting its Close until it
    gets the Reset, so ignoring the CloseReq while in state CLOSING is sane.

    2) Receiving Close

    The code below from 8.5 is unconditional.

    Step 14: Process Close
    If P.type == Close,
    Generate Reset(Closed)
    Tear down connection
    Drop packet and return

    Thus we need to consider all states:
    * CLOSED: silently ignore, since this can happen when a retransmitted or late Close arrives;
    * LISTEN: dccp_rcv_state_process() will generate a Reset ("No Connection");
    * REQUEST: perform Step 14 directly (no need to enqueue packet);
    * RESPOND: dccp_check_req() will generate a Reset ("Packet Error") -- left it at that;
    * OPEN/PARTOPEN: enter PASSIVE_CLOSE so that application has a chance to process unread data;
    * CLOSEREQ: server performed active-close -- perform Step 14;
    * CLOSING: simultaneous-close: use a tie-breaker to avoid message ping-pong (see comment);
    * PASSIVE_CLOSEREQ: ignore - the peer has a bug (sending first a CloseReq and now a Close);
    * TIMEWAIT: packet is ignored.

    Note that the condition of receiving a packet in state CLOSED here is different from the condition "there
    is no socket for such a connection": the socket still exists, but its state indicates it is unusable.

    Last, dccp_finish_passive_close sets either DCCP_CLOSED or DCCP_CLOSING = TCP_CLOSING, so that
    sk_stream_wait_close() will wait for the final Reset (which will trigger CLOSING => CLOSED).

    Signed-off-by: Gerrit Renker
    Signed-off-by: Arnaldo Carvalho de Melo
    Signed-off-by: David S. Miller

    Gerrit Renker
     
  • This adds two auxiliary states to deal with passive closes:
    * PASSIVE_CLOSE (reached from OPEN via reception of Close) and
    * PASSIVE_CLOSEREQ (reached from OPEN via reception of CloseReq)
    as internal intermediate states.

    These states are used to allow a receiver to process unread data before
    acknowledging the received connection-termination-request (the Close/CloseReq).

    Without such support, it will happen that passively-closed sockets enter CLOSED
    state while there is still unprocessed data in the queue; leading to unexpected
    and erratic API behaviour.

    PASSIVE_CLOSE has been mapped into TCPF_CLOSE_WAIT, so that the code will
    seamlessly work with inet_accept() (which tests for this state).

    The state names are thanks to Arnaldo, who suggested this naming scheme
    following an earlier revision of this patch.

    Signed-off-by: Gerrit Renker
    Signed-off-by: Arnaldo Carvalho de Melo
    Signed-off-by: David S. Miller

    Gerrit Renker
     
  • This decouples PARTOPEN from TCP-specific stream-states.

    It thus addresses the FIXME.

    The code has been checked with regard to dependency on PARTOPEN and FIN_WAIT1
    states (to which PARTOPEN previously was mapped): there is no difference, as
    PARTOPEN is always referred to directly (i.e. not via the mapping to TCP
    state).

    Signed-off-by: Gerrit Renker
    Signed-off-by: Ian McDonald
    Signed-off-by: Arnaldo Carvalho de Melo
    Signed-off-by: David S. Miller

    Gerrit Renker
     

24 Oct, 2007

2 commits

  • This adds support for converting the 11 currently defined Reset codes into system
    error numbers, which are stored in sk_err for further interpretation.

    This makes the externally visible API behaviour similar to TCP, since a client
    connecting to a non-existing port will experience ECONNREFUSED.

    * Code 0, Unspecified, is interpreted as non-error (0);
    * Code 1, Closed (normal termination), also maps into 0;
    * Code 2, Aborted, maps into "Connection reset by peer" (ECONNRESET);
    * Code 3, No Connection and
    Code 7, Connection Refused, map into "Connection refused" (ECONNREFUSED);
    * Code 4, Packet Error, maps into "No message of desired type" (ENOMSG);
    * Code 5, Option Error, maps into "Illegal byte sequence" (EILSEQ);
    * Code 6, Mandatory Error, maps into "Operation not supported on transport endpoint" (EOPNOTSUPP);
    * Code 8, Bad Service Code, maps into "Invalid request code" (EBADRQC);
    * Code 9, Too Busy, maps into "Too many users" (EUSERS);
    * Code 10, Bad Init Cookie, maps into "Invalid request descriptor" (EBADR);
    * Code 11, Aggression Penalty, maps into "Quota exceeded" (EDQUOT)
    which makes sense in terms of using more than the `fair share' of bandwidth.

    Signed-off-by: Gerrit Renker
    Acked-by: Ian McDonald
    Signed-off-by: Arnaldo Carvalho de Melo

    Gerrit Renker
     
  • This fixes a problem when analysing erroneous packets in dccp_v{4,6}_err:
    * dccp_hdr_seq currently takes an skb
    * however, the transport headers in the skb are shifted, due to the
    preceding IPv4/v6 header.
    Fixed for v4 and v6 by changing dccp_hdr_seq to take a struct dccp_hdr as
    argument. Verified that the correct sequence number is now reported in the
    error handler.

    Signed-off-by: Gerrit Renker
    Acked-by: Ian McDonald
    Signed-off-by: Arnaldo Carvalho de Melo

    Gerrit Renker
     

11 Oct, 2007

6 commits

  • This

    * removes a declaration of a non-existent function
    __dccp_minisock_init;

    * shifts the initialisation function dccp_minisock_init() from
    options.c to minisocks.c, where it is more naturally expected to
    be.

    Signed-off-by: Gerrit Renker
    Signed-off-by: Ian McDonald
    Signed-off-by: Arnaldo Carvalho de Melo
    Signed-off-by: David S. Miller

    Gerrit Renker
     
  • This enables applications to query the current value of the Maximum
    Packet Size via a socket option, suggested as a SHOULD in (RFC 4340,
    p. 102).

    This socket option is useful to avoid the annoying bail-out via
    `-EMSGSIZE'. In particular, as fragmentation is not currently
    supported (and its use is partly discouraged in RFC 4340).

    With this option, it is possible to size buffers accordingly, e.g.

    int buflen = dccp_get_cur_mps(sockfd);

    /* or */
    if (msgsize > dccp_get_cur_mps(sockfd))
    die("message is too large for this path");

    Signed-off-by: Gerrit Renker
    Signed-off-by: Ian McDonald
    Signed-off-by: Arnaldo Carvalho de Melo
    Signed-off-by: David S. Miller

    Gerrit Renker
     
  • This implements a SHOULD from RFC 4340, 7.5.4:
    "To protect against denial-of-service attacks, DCCP implementations SHOULD
    impose a rate limit on DCCP-Syncs sent in response to sequence-invalid packets,
    such as not more than eight DCCP-Syncs per second."

    The rate-limit is maintained on a per-socket basis. This is a more stringent
    policy than enforcing the rate-limit on a per-source-address basis and
    protects against attacks with forged source addresses.

    Moreover, the mechanism is deliberately kept simple. In contrast to
    xrlim_allow(), bursts of Sync packets in reply to sequence-invalid packets
    are not supported. This foils such attacks where the receipt of a Sync
    triggers further sequence-invalid packets. (I have tested this mechanism against
    xrlim_allow algorithm for Syncs, permitting bursts just increases the problems.)

    In order to keep flexibility, the timeout parameter can be set via sysctl; and
    the whole mechanism can even be disabled (which is however not recommended).

    The algorithm in this patch has been improved with regard to wrapping issues
    thanks to a suggestion by Arnaldo.

    Commiter note: Rate limited the step 6 DCCP_WARN too, as it says we're
    sending a sync.

    Signed-off-by: Gerrit Renker
    Signed-off-by: Ian McDonald
    Signed-off-by: Arnaldo Carvalho de Melo

    Gerrit Renker
     
  • This adds fields to support the informational Data 1..3 fields of the
    DCCP-Reset packets (RFC 4340, 5.6), and makes minor cosmetic changes
    to documentation.
    Code which fills in these fields follows in subsequent patches, it is
    primarily used for reporting option-processing and feature-negotiation
    errors.

    Signed-off-by: Gerrit Renker
    Signed-off-by: Arnaldo Carvalho de Melo

    Gerrit Renker
     
  • Signed-off-by: Arnaldo Carvalho de Melo
    Signed-off-by: David S. Miller

    Arnaldo Carvalho de Melo
     
  • Signed-off-by: Arnaldo Carvalho de Melo
    Signed-off-by: David S. Miller

    Arnaldo Carvalho de Melo
     

26 Apr, 2007

4 commits


12 Dec, 2006

1 commit