This extends the existing wait-for-ccid routine so that it may be used with
different types of CCID. It further addresses the problems listed below.
The code looks if the write queue is non-empty and grants the TX CCID up to
`timeout' jiffies to drain the queue. It will instead purge that queue if
* the delay suggested by the CCID exceeds the time budget;
* a socket error occurred while waiting for the CCID;
* there is a signal pending (eg. annoyed user pressed Control-C);
* the CCID does not support delays (we don't know how long it will take).
D e t a i l s [can be removed]
-------------------------------
DCCP's sending mechanism functions a bit like non-blocking I/O: dccp_sendmsg()
will enqueue up to net.dccp.default.tx_qlen packets (default=5), without waiting
for them to be released to the network.
Rate-based CCIDs, such as CCID3/4, can impose sending delays of up to maximally
64 seconds (t_mbi in RFC 3448). Hence the write queue may still contain packets
when the application closes. Since the write queue is congestion-controlled by
the CCID, draining the queue is also under control of the CCID.
There are several problems that needed to be addressed:
1) The queue-drain mechanism only works with rate-based CCIDs. If CCID2 for
example has a full TX queue and becomes network-limited just as the
application wants to close, then waiting for CCID2 to become unblocked could
lead to an indefinite delay (i.e., application "hangs").
2) Since each TX CCID in turn uses a feedback mechanism, there may be changes
in its sending policy while the queue is being drained. This can lead to
further delays during which the application will not be able to terminate.
3) The minimum wait time for CCID3/4 can be expected to be the queue length
times the current inter-packet delay. For example if tx_qlen=100 and a delay
of 15 ms is used for each packet, then the application would have to wait
for a minimum of 1.5 seconds before being allowed to exit.
4) There is no way for the user/application to control this behaviour. It would
be good to use the timeout argument of dccp_close() as an upper bound. Then
the maximum time that an application is willing to wait for its CCIDs to can
be set via the SO_LINGER option.
These problems are addressed by giving the CCID a grace period of up to the
`timeout' value.
The wait-for-ccid function is, as before, used when the application
(a) has read all the data in its receive buffer and
(b) if SO_LINGER was set with a non-zero linger time, or
(c) the socket is either in the OPEN (active close) or in the PASSIVE_CLOSEREQ
state (client application closes after receiving CloseReq).
In addition, there is a catch-all case by calling __skb_queue_purge() after
waiting for the CCID. This is necessary since the write queue may still have
data when
(a) the host has been passively-closed,
(b) abnormal termination (unread data, zero linger time),
(c) wait-for-ccid could not finish within the given time limit.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
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 CCID2 out of its polling mode (when it is network-
limited, it tries every millisecond to send, without interruption).
The interface can also be used to support other CCIDs.
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.
If the tasklet finds that the socket is locked, it re-schedules the tasklet
function (not the tasklet) after one jiffy.
Changed DCCP_BUG to dccp_pr_debug when transmit_skb returns an error (e.g. when a
local qdisc is used, NET_XMIT_DROP=1 can be returned for many packets).
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
This patch reorganises the return value convention of the CCID TX sending
function, to permit more flexible schemes, as required by subsequent patches.
Currently the convention is
* values < 0 mean error,
* a value == 0 means "send now", and
* a value x > 0 means "send in x milliseconds".
The patch provides symbolic constants and a function to interpret return values.
In addition, it caps the maximum positive return value to 0xFFFF milliseconds,
corresponding to 65.535 seconds.
This is possible since in CCID-3 the maximum inter-packet gap is t_mbi = 64 sec.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
This patch replaces an almost identical replication of code: large parts
of dccp_parse_options() re-appeared as ccid2_ackvector() in ccid2.c.
Apart from the duplication, this caused two more problems:
1. CCIDs should not need to be concerned with parsing header options;
2. one can not assume that Ack Vectors appear as a contiguous area within an
skb, it is legal to insert other options and/or padding in between. The
current code would throw an error and stop reading in such a case.
The patch provides a new data structure and associated list housekeeping.
Only small changes were necessary to integrate with CCID-2: data structure
initialisation, adapt list traversal routine, and add call to the provided
cleanup routine.
The latter also lead to fixing the following BUG: CCID-2 so far ignored
Ack Vectors on all packets other than Ack/DataAck, which is incorrect,
since Ack Vectors can be present on any packet that has an Ack field.
Details:
--------
* received Ack Vectors are parsed by dccp_parse_options() alone, which passes
the result on to the CCID-specific routine ccid_hc_tx_parse_options();
* CCIDs interested in using/decoding Ack Vector information will add code
to fetch parsed Ack Vectors via this interface;
* a data structure, `struct dccp_ackvec_parsed' is provided as interface;
* this structure arranges Ack Vectors of the same skb into a FIFO order;
* a doubly-linked list is used to keep the required FIFO code small.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
This removes
* functions for which updates have been provided in the preceding patches and
* the @av_vec_len field - it is no longer necessary since the buffer length is
now always computed dynamically;
* conditional debugging code (CONFIG_IP_DCCP_ACKVEC).
The reason for removing the conditional debugging code is that Ack Vectors are
an almost inevitable necessity - RFC 4341 says that for CCID-2, Ack Vectors must
be used. Furthermore, the code would be only interesting for coding - after some
extensive testing with this patch set, having the debug code around is no longer
of real help.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
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 (previous patch), 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.
It can thus serve other parts of the DCCP code as well.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
This aggregates Ack Vector processing (handling input and clearing old state)
into one function, for the following reasons and benefits:
* all Ack Vector-specific processing is now in one place;
* duplicated code is removed;
* ensuring sanity: from an Ack Vector point of view, it is better to clear the
old state first before entering new state;
* Ack Event handling happens mostly within the CCIDs, not the main DCCP module.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
This patch uupdates the code which registers new packets as received, using the
new circular buffer interface. It contributes a new algorithm which
* supports both tail/head pointers and buffer wrap-around and
* deals with overflow (head/tail move in lock-step).
The updated code is also partioned differently, into
1. dealing with the empty buffer,
2. adding new packets into non-empty buffer,
3. reserving space when encountering a `hole' in the sequence space,
4. updating old state and deciding when old state is irrelevant.
Protection against large burst losses: With regard to (3), it is too costly to
reserve space when there are large bursts of losses. When bursts get too large,
the code does no longer reserve space and just fills in cells normally. This
measure reduces space consumption by a factor of 63.
The code reuses in part the previous implementation by Arnaldo de Melo.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
This provides a routine to consistently update the buffer state when the
peer acknowledges receipt of Ack Vectors; updating state in the list of Ack
Vectors as well as in the circular buffer.
While based on RFC 4340, several additional (and necessary) precautions were
added to protect the consistency of the buffer state. These additions are
essential, since analysis and experience showed that the basic algorithm was
insufficient for this task (which lead to problems that were hard to debug).
The algorithm now
* deals with HC-sender acknowledging to HC-receiver and vice versa,
* keeps track of the last unacknowledged but received seqno in tail_ackno,
* has special cases to reset the overflow condition when appropriate,
* is protected against receiving older information (would mess up buffer state).
Note: The older code performed an unnecessary step, where the sender cleared
Ack Vector state by parsing the Ack Vector received by the HC-receiver. Doing
this was entirely redundant, since
* the receiver always puts the full acknowledgment window (groups 2,3 in 11.4.2)
into the Ack Vectors it sends; hence the HC-receiver is only interested in the
highest state that the HC-sender received;
* this means that the acknowledgment number on the (Data)Ack from the HC-sender
is sufficient; and work done in parsing earlier state is not necessary, since
the later state subsumes the earlier one (see also RFC 4340, A.4).
This older interface (dccp_ackvec_parse()) is therefore removed.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
This completes the implementation of a circular buffer for Ack Vectors, by
extending the current (linear array-based) implementation. The changes are:
(a) An `overflow' flag to deal with the case of overflow. As before, dynamic
growth of the buffer will not be supported; but code will be added to deal
robustly with overflowing Ack Vector buffers.
(b) A `tail_seqno' field. When naively implementing the algorithm of Appendix A
in RFC 4340, problems arise whenever subsequent Ack Vector records overlap,
which can bring the entire run length calculation completely out of synch.
(This is documented on http://www.erg.abdn.ac.uk/users/gerrit/dccp/notes/\
ack_vectors/tracking_tail_ackno/ .)
(c) The buffer lengthi is now computed dynamically (i.e. current fill level),
as the span between head to tail.
As a result, dccp_ackvec_pending() is now simpler - the #ifdef is no longer
necessary since buf_empty is always true when IP_DCCP_ACKVEC is not configured.
Note on overflow handling:
-------------------------
The Ack Vector code previously simply started to drop packets when the
Ack Vector buffer overflowed. This means that the userspace application
will not be able to receive, only because of an Ack Vector storage problem.
Furthermore, overflow may be transient, so that applications may later
recover from the overflow. Recovering from dropped packets is more difficult
(e.g. video key frames).
Hence the patch uses a different policy: when the buffer overflows, the oldest
entries are subsequently overwritten. This has a higher chance of recovery.
Details are on http://www.erg.abdn.ac.uk/users/gerrit/dccp/notes/ack_vectors/
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
This patch
* separates Ack Vector housekeeping code from option-insertion code;
* shifts option-specific code from ackvec.c into options.c;
* introduces a dedicated routine to take care of the Ack Vector records;
* simplifies the dccp_ackvec_insert_avr() routine: the BUG_ON was redundant,
since the list is automatically arranged in descending order of ack_seqno.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
This patch brings the Ack Vector interface up to date. Its main purpose is
to lay the basis for the subsequent patches of this set, which will use the
new data structure fields and routines.
There are no real algorithmic changes, rather an adaptation:
(1) Replaced the static Ack Vector size (2) with a #define so that it can
be adapted (with low loss / Ack Ratio, a value of 1 works, so 2 seems
to be sufficient for the moment) and added a solution so that computing
the ECN nonce will continue to work - even with larger Ack Vectors.
(2) Replaced the #defines for Ack Vector states with a complete enum.
(3) Replaced #defines to compute Ack Vector length and state with general
purpose routines (inlines), and updated code to use these.
(4) Added a `tail' field (conversion to circular buffer in subsequent patch).
(5) Updated the (outdated) documentation for Ack Vector struct.
(6) All sequence number containers now trimmed to 48 bits.
(7) Removal of unused bits:
* removed dccpav_ack_nonce from struct dccp_ackvec, since this is already
redundantly stored in the `dccpavr_ack_nonce' (of Ack Vector record);
* removed Elapsed Time for Ack Vectors (it was nowhere used);
* replaced semantics of dccpavr_sent_len with dccpavr_ack_runlen, since
the code needs to be able to remember the old run length;
* reduced the de-/allocation routines (redundant / duplicate tests).
Justification for removing Elapsed Time information [can be removed]:
---------------------------------------------------------------------
1. The Elapsed Time information for Ack Vectors was nowhere used in the code.
2. DCCP does not implement rate-based pacing of acknowledgments. The only
recommendation for always including Elapsed Time is in section 11.3 of
RFC 4340: "Receivers that rate-pace acknowledgements SHOULD [...]
include Elapsed Time options". But such is not the case here.
3. It does not really improve estimation accuracy. The Elapsed Time field only
records the time between the arrival of the last acknowledgeable packet and
the time the Ack Vector is sent out. Since Linux does not (yet) implement
delayed Acks, the time difference will typically be small, since often the
arrival of a data packet triggers sending feedback at the HC-receiver.
Justification for changes in de-/allocation routines [can be removed]:
----------------------------------------------------------------------
* INIT_LIST_HEAD in dccp_ackvec_record_new was redundant, since the list
pointers were later overwritten when the node was added via list_add();
* dccp_ackvec_record_new() was called in a single place only;
* calls to list_del_init() before calling dccp_ackvec_record_delete() were
redundant, since subsequently the entire element was k-freed;
* since all calls to dccp_ackvec_record_delete() were preceded to a call to
list_del_init(), the WARN_ON test would never evaluate to true;
* since all calls to dccp_ackvec_record_delete() were made from within
list_for_each_entry_safe(), the test for avr == NULL was redundant;
* list_empty() in ackvec_free was redundant, since the same condition is
embedded in the loop condition of the subsequent list_for_each_entry_safe().
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
This fixes the problem that dccp_probe output can grow quite large without
apparent benefit (many identical data points), creating huge files (up to
over one Gigabyte for a few minutes' test run) which are very hard to
post-process (in one instance it got so bad that gnuplot ate up all memory
plus swap).
The cause for the problem is that the kprobe is inserted into dccp_sendmsg(),
which can be called in a polling-mode (whenever the TX queue is full due to
congestion-control issues, EAGAIN is returned). This creates many very
similar data points, i.e. the increase of processing time does not increase
the quality/information of the probe output.
The fix is to attach the probe to a different function -- write_xmit was
chosen since it gets called continually (both via userspace and timer);
an input-path function would stop sampling as soon as the other end stops
sending feedback.
For comparison the output file sizes for the same 20 second test
run over a lossy link:
* before / without patch: 118 Megabytes
* after / with patch: 1.2 Megabytes
and there was much less noise in the output.
To allow backward compatibility with scripts that people use, the now-unused
`size' field in the output has been replaced with the CCID identifier. This
also serves for future compatibility - support for CCID2 is work in progress
(depends on the still unfinished SRTT/RTTVAR updates).
While at it, the update to ktime_t was also performed.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
After moving the assignment of GAR/ISS from dccp_connect_init() to
dccp_transmit_skb(), the former function becomes very small, so that
a merger with dccp_connect() suggests itself.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
This fixes a problem and a potential loophole with regard to seqno/ackno
validity: the problem is that the initial adjustments to AWL/SWL were
only performed at the begin of the connection, during the handshake.
Since the Sequence Window feature is always greater than Wmin=32 (7.5.2),
it is however necessary to perform these adjustments at least for the first
W/W' (variables as per 7.5.1) packets in the lifetime of a connection.
This requirement is complicated by the fact that W/W' can change at any time
during the lifetime of a connection.
Therefore the consequence is to perform this safety check each time SWL/AWL
are updated.
A second problem solved by this patch is that the remote/local Sequence Window
feature values (which set the bounds for AWL/SWL/SWH) are undefined until the
feature negotiation has completed.
During the initial handshake we have more stringent sequence number protection,
the changes added by this patch effect that {A,S}W{L,H} are within the correct
bounds at the instant that feature negotiation completes (since the SeqWin
feature activation handlers call dccp_update_gsr/gss()).
A detailed rationale is below -- can be removed from the commit message.
1. Server sequence number checks during initial handshake
---------------------------------------------------------
The server can not use the fields of the listening socket for seqno/ackno checks
and thus needs to store all relevant information on a per-connection basis on
the dccp_request socket. This is a size-constrained structure and has currently
only ISS (dreq_iss) and ISR (dreq_isr) defined.
Adding further fields (SW{L,H}, AW{L,H}) would increase the size of the struct
and it is questionable whether this will have any practical gain. The currently
implemented solution is as follows.
* receiving first Request: dccp_v{4,6}_conn_request sets
ISR := P.seqno, ISS := dccp_v{4,6}_init_sequence()
* sending first Response: dccp_v{4,6}_send_response via dccp_make_response()
sets P.seqno := ISS, sets P.ackno := ISR
* receiving retransmitted Request: dccp_check_req() overrides ISR := P.seqno
* answering retransmitted Request: dccp_make_response() sets ISS += 1,
otherwise as per first Response
* completing the handshake: succeeds in dccp_check_req() for the first Ack
where P.ackno == ISS (P.seqno is not tested)
* creating child socket: ISS, ISR are copied from the request_sock
This solution will succeed whenever the server can receive the Request and the
subsequent Ack in succession, without retransmissions. If there is packet loss,
the client needs to retransmit until this condition succeeds; it will otherwise
eventually give up. Adding further fields to the request_sock could increase
the robustness a bit, in that it would make possible to let a reordered Ack
(from a retransmitted Response) pass. The argument against such a solution is
that if the packet loss is not persistent and an Ack gets through, why not
wait for the one answering the original response: if the loss is persistent, it
is probably better to not start the connection in the first place.
Long story short: the present design (by Arnaldo) is simple and will likely work
just as well as a more complicated solution. As a consequence, {A,S}W{L,H} are
not needed until the moment the request_sock is cloned into the accept queue.
At that stage feature negotiation has completed, so that the values for the local
and remote Sequence Window feature (7.5.2) are known, i.e. we are now in a better
position to compute {A,S}W{L,H}.
2. Client sequence number checks during initial handshake
---------------------------------------------------------
Until entering PARTOPEN the client does not need the adjustments, since it
constrains the Ack window to the packet it sent.
* sending first Request: dccp_v{4,6}_connect() choose ISS,
dccp_connect() then sets GAR := ISS (as per 8.5),
dccp_transmit_skb() (with the previous bug fix) sets
GSS := ISS, AWL := ISS, AWH := GSS
* n-th retransmitted Request (with previous patch):
dccp_retransmit_skb() via timer calls
dccp_transmit_skb(), which sets GSS := ISS+n
and then AWL := ISS, AWH := ISS+n
* receiving any Response: dccp_rcv_request_sent_state_process()
-- accepts packet if AWL <= P.ackno <= AWH;
-- sets GSR = ISR = P.seqno
* sending the Ack completing the handshake: dccp_send_ack() calls
dccp_transmit_skb(), which sets GSS += 1
and AWL := ISS, AWH := GSS
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
This schedules an Ack when receiving a timestamp, exploiting the
existing inet_csk_schedule_ack() function, saving one case in the
`dccp_ack_pending()' function.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
This patch is thanks to an investigation by Leandro Sales de Melo and his
colleagues. They worked out two state diagrams which highlight the fact that
the xxx_TERM states in CCID-3/4 are in fact not necessary.
And this can be confirmed by in turn looking at the code: the xxx_TERM states
are only ever set in ccid3_hc_{rx,tx}_exit(). These two functions are part
of the following call chain:
* ccid_hc_{tx,rx}_exit() are called from ccid_delete() only;
* ccid_delete() invokes ccid_hc_{tx,rx}_exit() in the way of a destructor:
after calling ccid_hc_{tx,rx}_exit(), the CCID is released from memory;
* ccid_delete() is in turn called only by ccid_hc_{tx,rx}_delete();
* ccid_hc_{tx,rx}_delete() is called only if
- feature negotiation failed (dccp_feat_activate_values()),
- when changing the RX/TX CCID (to eject the current CCID),
- when destroying the socket (in dccp_destroy_sock()).
In other words, when CCID-3 sets the state to xxx_TERM, it is at a time where
no more processing should be going on, hence it is not necessary to introduce
a dedicated exit state - this is implicit when unloading the CCID.
The patch removes this state, one switch-statement collapses as a result.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
This removes the argument `more' from ccid_hc_tx_packet_sent, since it was
nowhere used in the entire code.
(Anecdotally, this argument was not even used in the original KAME code where
the function originally came from; compare the variable moreToSend in the
freebsd61-dccp-kame-28.08.2006.patch now maintained by Emmanuel Lochin.)
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
The constants DCCPO_{MIN,MAX}_CCID_SPECIFIC are nowhere used in the code, but
instead for the CCID-specific options numbers are used.
This patch unifies the use of CCID-specific option numbers, by adding symbolic
names reflecting the definitions in RFC 4340, 10.3.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
The `options_received' struct is redundant, since it re-duplicates the existing
`p' and `x_recv' fields. This patch removes the sub-struct and migrates the
format conversion operations (cf. below) to ccid3_hc_tx_parse_options().
Why the fields are redundant
----------------------------
The Loss Event Rate p and the Receive Rate x_recv are initially 0 when first
loading CCID-3, as ccid_new() zeroes out the entire ccid3_hc_tx_sock.
When Loss Event Rate or Receive Rate options are received, they are stored by
ccid3_hc_tx_parse_options() into the fields `ccid3or_loss_event_rate' and
`ccid3or_receive_rate' of the sub-struct `options_received' in ccid3_hc_tx_sock.
After parsing (considering only the established state - dccp_rcv_established()),
the packet is passed on to ccid_hc_tx_packet_recv(). This calls the CCID-3
specific routine ccid3_hc_tx_packet_recv(), which performs the following copy
operations between fields of ccid3_hc_tx_sock:
* hctx->options_received.ccid3or_receive_rate is copied into hctx->x_recv,
after scaling it for fixpoint arithmetic, by 2^64;
* hctx->options_received.ccid3or_loss_event_rate is copied into hctx->p,
considering the above special cases; in addition, a value of 0 here needs to
be mapped into p=0 (when no Loss Event Rate option has been received yet).
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
This adds a function to take care of the following cases occurring in the
computation of the Loss Rate p:
* 1/(2^32-1) is mapped into 0% as per RFC 4342, 8.5;
* 1/0 is mapped into the maximum of 100%;
* we want to avoid that p = 1/x is rounded down to 0 when x is very large,
since this means accidentally re-entering slow-start (indicated by p==0).
In the last case, the minimum-resolution value of p is returned.
Furthermore, a bug in ccid3_hc_rx_getsockopt is fixed (1/0 was mapped into ~0U),
which now allows to consistently print the scaled p-values as
printf("Loss Event Rate = %u.%04u %%\n", rx_info.tfrcrx_p / 10000,
rx_info.tfrcrx_p % 10000);
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
This patch ...
1. adds packet type information to ccid_hc_{rx,tx}_parse_options(). This is
necessary, since table 3 in RFC 4340, 5.8 leaves it to the CCIDs to state
which options may (not) appear on what packet type.
2. adds such a check for CCID-3's {Loss Event, Receive} Rate as specified in
RFC 4340 8.3 ("Receive Rate options MUST NOT be sent on DCCP-Data packets")
and 8.5 ("Loss Event Rate options MUST NOT be sent on DCCP-Data packets").
3. removes an unused argument `idx' from ccid_hc_{rx,tx}_parse_options(). This
is also no longer necessary, since the CCID-specific option-parsing routines
are passed every single parameter of the type-length-value option encoding.
Also added documentation and made argument naming scheme consistent.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
This simplifies and consolidates the TX option-parsing code:
1. The Loss Intervals option is not currently used, so dead code related to
this option is removed. I am aware of no plans to support the option, but
if someone wants to implement it (e.g. for inter-op tests), it is better
to start afresh than having to also update currently unused code.
2. The Loss Event and Receive Rate options have a lot of code in common (both
are 32 bit, both have same length etc.), so this is consolidated.
3. The test against GSR is not necessary, because
- on first loading CCID3, ccid_new() zeroes out all fields in the socket;
- ccid3_hc_tx_packet_recv() treats 0 and ~0U equivalently, due to
pinv = opt_recv->ccid3or_loss_event_rate;
if (pinv == ~0U || pinv == 0)
hctx->p = 0;
- as a result, the sequence number field is removed from opt_recv.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
This removes the RTT-sampling function tfrc_tx_hist_rtt(), since
1. it suffered from complex passing of return values (the return value both
indicated successful lookup while the value doubled as RTT sample);
2. when for some odd reason the sample value equalled 0, this triggered a bug
warning about "bogus Ack", due to the ambiguity of the return value;
3. on a passive host which has not sent anything the TX history is empty and
thus will lead to unwanted "bogus Ack" warnings such as
ccid3_hc_tx_packet_recv: server(e7b7d518): DATAACK with bogus ACK-28197148
ccid3_hc_tx_packet_recv: server(e7b7d518): DATAACK with bogus ACK-26641606.
The fix is to replace the implicit encoding by performing the steps manually.
Furthermore, the "bogus Ack" warning has been removed, since it can actually be
triggered due to several reasons (network reordering, old packet, (3) above),
hence it is not very useful.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
This fixes a subtle bug in the calculation of the inter-packet gap and shows
that t_delta, as it is currently used, is not needed. And hence replaced.
The algorithm from RFC 3448, 4.6 below continually computes a send time t_nom,
which is initialised with the current time t_now; t_gran = 1E6 / HZ specifies
the scheduling granularity, s the packet size, and X the sending rate:
t_distance = t_nom - t_now; // in microseconds
t_delta = min(t_ipi, t_gran) / 2; // `delta' parameter in microseconds
if (t_distance >= t_delta) {
reschedule after (t_distance / 1000) milliseconds;
} else {
t_ipi = s / X; // inter-packet interval in usec
t_nom += t_ipi; // compute the next send time
send packet now;
}
1) Description of the bug
-------------------------
Rescheduling requires a conversion into milliseconds, due to this call chain:
* ccid3_hc_tx_send_packet() returns a timeout in milliseconds,
* this value is converted by msecs_to_jiffies() in dccp_write_xmit(),
* and finally used as jiffy-expires-value for sk_reset_timer().
The highest jiffy resolution with HZ=1000 is 1 millisecond, so using a higher
granularity does not make much sense here.
As a consequence, values of t_distance < 1000 are truncated to 0. This issue
has so far been resolved by using instead
if (t_distance >= t_delta + 1000)
reschedule after (t_distance / 1000) milliseconds;
The bug is in artificially inflating t_delta to t_delta' = t_delta + 1000. This
is unnecessarily large, a more adequate value is t_delta' = max(t_delta, 1000).
2) Consequences of using the corrected t_delta'
-----------------------------------------------
Since t_delta <= t_gran/2 = 10^6/(2*HZ), we have t_delta <= 1000 as long as
HZ >= 500. This means that t_delta' = max(1000, t_delta) is constant at 1000.
On the other hand, when using a coarse HZ value of HZ < 500, we have three
sub-cases that can all be reduced to using another constant of t_gran/2.
(a) The first case arises when t_ipi > t_gran. Here t_delta' is the constant
t_delta' = max(1000, t_gran/2) = t_gran/2.
(b) If t_ipi <= 2000 < t_gran = 10^6/HZ usec, then t_delta = t_ipi/2 <= 1000,
so that t_delta' = max(1000, t_delta) = 1000 < t_gran/2.
(c) If 2000 < t_ipi <= t_gran, we have t_delta' = max(t_delta, 1000) = t_ipi/2.
In the second and third cases we have delay values less than t_gran/2, which is
in the order of less than or equal to half a jiffy.
How these are treated depends on how fractions of a jiffy are handled: they
are either always rounded down to 0, or always rounded up to 1 jiffy (assuming
non-zero values). In both cases the error is on average in the order of 50%.
Thus we are not increasing the error when in the second/third case we replace
a value less than t_gran/2 with 0, by setting t_delta' to the constant t_gran/2.
3) Summary
----------
Fixing (1) and considering (2), the patch replaces t_delta with a constant,
whose value depends on CONFIG_HZ, changing the above algorithm to:
if (t_distance >= t_delta')
reschedule after (t_distance / 1000) milliseconds;
where t_delta' = 10^6/(2*HZ) if HZ < 500, and t_delta' = 1000 otherwise.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
The CCIDs are activated as last of the features, at the end of the handshake,
were the LISTEN state of the master socket is inherited into the server
state of the child socket. Thus, the only states visible to CCIDs now are
OPEN/PARTOPEN, and the closing states.
This allows to remove tests which were previously necessary to protect
against referencing a socket in the listening state (in CCID3), but which
now have become redundant.
As a further byproduct of enabling the CCIDs only after the connection has been
fully established, several typecast-initialisations of ccid3_hc_{rx,tx}_sock
can now be eliminated:
* the CCID is loaded, so it is not necessary to test if it is NULL,
* if it is possible to load a CCID and leave the private area NULL, then this
is a bug, which should crash loudly - and earlier,
* the test for state==OPEN || state==PARTOPEN now reduces only to the closing
phase (e.g. when the node has received an unexpected Reset).
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
This patch does the same for CCID-3 as the previous patch for CCID-2:
s#ccid3hctx_##g;
s#ccid3hcrx_##g;
plus manual editing to retain consistency.
Please note: expanded the fields of the `struct tfrc_tx_info' in the hc_tx_sock,
since using short #define identifiers is not a good idea. The only place where
this embedded struct was used is ccid3_hc_tx_getsockopt().
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
This patch fixes two problems caused by the ubiquitous long "hctx->ccid2htx_"
and "hcrx->ccid2hcrx_" prefixes:
* code becomes hard to read;
* multiple-line statements are almost inevitable even for simple expressions;
The prefixes are not really necessary (compare with "struct tcp_sock").
There had been previous discussion of this on dccp@vger, but so far this was
not followed up (most people agreed that the prefixes are too long).
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Leandro Melo de Sales <leandroal@gmail.com>
To increase robustness, it is necessary to resend Confirm feature-negotiation
options, even though the RFC does not mandate it. But feature negotiation
options can take (much) more room than the options on common DataAck packets.
Instead of reducing the MPS always for a case which only applies to the three
messages send during initial handshake, this patch devises a special case:
if the payload length of the DataAck in PARTOPEN is too large, an Ack is sent
to carry the options, and the feature-negotiation list is then flushed.
This means that the server gets two Acks for one Response. If both Acks get
lost, it is probably better to restart the connection anyway and devising yet
another special-case does not seem worth the extra complexity.
The patch (over-)estimates the expected overhead to be 32*4 bytes -- commonly
seen values were 20-90 bytes for initial feature-negotiation options.
It uses sizeof(u32) to mean "aligned units of 4 bytes". For consistency,
another use of sizeof is modified.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
The Maximum Packet Size (MPS) is of interest for applications which want
to transfer data, so it is only relevant to the data transfer phase of a
connection (unless one wants to send data on the DCCP-Request, but that is
not considered here).
The strategy chosen to deal with this requirement is to leave room for only
such options that may appear on data packets.
A special consideration applies to Ack Vectors: this is purely guesswork,
since these can have any length between 3 and 1020 bytes. The strategy
chosen here is to subtract a configurable minimum, the value of 16 bytes
(2 bytes for type/length plus 14 Ack Vector cells) has been found by
experimentatation. If people experience this as too much or too little,
this could later be turned into a Kconfig option.
There are currently no CCID-specific header options which may appear on data
packets, hence it is not necessary to define a corresponding CCID field.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
This uses the new feature-negotiation framework to signal Ack Ratio changes,
as required by RFC 4341, sec. 6.1.2.
This raises some problems for CCID-2 since it can at the moment not cope
gracefully with Ack Ratio of e.g. 2. A FIXME has thus been added which
reverts to the existing policy of bypassing the Ack Ratio sysctl.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
This patch provides support for the reception of NN options in (PART)OPEN state.
It is a combination of change_recv() and confirm_recv(), specifically geared
towards receiving the `fast-path' NN options.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
In contrast to static feature negotiation at the begin of a connection, which
establishes the capabilities of both endpoints, this patch introduces support
for dynamic exchange of feature negotiation options.
Such a dynamic exchange is necessary in at least two cases:
* CCID-2's Ack Ratio (RFC 4341, 6.1.2) which changes during the connection;
* Sequence Window values that, as per RFC 4340, 7.5.2, should be sent "as
as the connection progresses".
Both are NN (non-negotiable) features. Hence dynamic feature "negotiation" is
distinguished from static/pre-connection negotiation by the following:
* no new capabilities are negotiated (those that matter for the connection
are negotiated prior to setting up the connection, comparable to SIP);
* features must be understood by each endpoint: as per RFC 4340, 6.4,
Sequence Window is "Req'd" and Ack Ratio must be understood when CCID-2
is used as per the note underneath Table 4.
These characteristics are reflected in the implementation:
* only NN options can be exchanged after connection setup;
* NN options are activated directly after validating them. The rationale is
that a peer must accept every valid NN value (RFC 4340, 6.3.2), hence it
will either accept the value and send a "Confirm R", or it will send an
empty Confirm (which will reset the connection according to FN rules).
* An Ack is scheduled directly after activation to accelerate communicating
the update to the peer.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Since all feature-negotiation processing now takes place in feat.c, functions
for producing verbose debugging output are concentrated there.
New functions to print out values, entry records, and options are provided,
and also a macro is defined to not always have the function name in the
output line.
Thanks a lot to Wei Yongjun and Giuseppe Galeota for help with errors in an
earlier revision of this patch.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
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 act on 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.
Further changes:
----------------
Performed s@sysctl_dccp_feat@sysctl_dccp@g since the sysctls are now in feat.c.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
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 changes are introduced:
* 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.
Until the handshake completes with activating negotiated values, the local/remote
Sequence-Window values are undefined and thus can not reliably be estimated.
This issue is addressed in a separate patch.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
This adds auto-loading of CCIDs (when module loading is enabled)
for the purpose of feature negotiation.
The problem with loading the CCIDs at the end of feature negotiation is
that this would happen in software interrupt context. Besides, if the host
advertises CCIDs during negotiation, it should have them ready to use, in
case an agreeing peer wants to use it for the connection.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
This initialises feature negotiation from two tables, which are initialised
from sysctls.
As a novel feature, specifics of the implementation (e.g. currently short
seqnos and ECN are not supported) are advertised for robustness.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
This removes the use of the sysctl and the minisock variable for the Send Ack
Vector feature, which is now handled fully dynamically via feature negotiation;
i.e. when CCID2 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.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
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 is with 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 <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
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 earlier in this
patch set.
Also removed 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 <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
The code removed by this patch is no longer referenced or used, the added
lines update documentation and copyrights.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
This integrates feature-activation in the client, with these details:
1. When dccp_parse_options() fails, the reset code is already set, request_sent
_state_process() currently overrides this with `Packet Error', which is not
intended - so changed to use the reset code set in dccp_parse_options();
2. There was a FIXME to change the error code when dccp_ackvec_add() fails.
I have looked this up and found 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.
3. When feature negotiation fails, the socket should be marked as not usable,
so that the application is notified that an error occurs. This is achieved
by a new label, which uses an error code of `Aborted' and which sets the
socket state to CLOSED, as well as sk_err.
4. Avoids parsing the Ack twice in Respond state by not doing option processing
again in dccp_rcv_respond_partopen_state_process (as option processing has
already been done on the request_sock in dccp_check_req).
Since this addresses congestion-control initialisation, a corresponding
FIXME has been removed.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
This patch integrates the activation of features at the end of negotiation
into the server-side code.
Note:
In dccp_create_openreq_child the request_sock argument is no longer constant,
since dccp_activate_values() uses the feature-negotiation list on dreq to sort
out the initialisation values for the different features of the child socket;
and purges this queue after use (but the `req' argument to openreq_child
can and does still remain constant).
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
This first patch out of three replaces the hardcoded default settings with
initialisation code for the dynamic feature negotiation.
Note on retransmitting Confirm options:
---------------------------------------
This patch also defers flushing the client feature-negotiation queue,
due to the following considerations.
As long as the client is in PARTOPEN, it needs to retransmit the Confirm
options for the Change options received on the DCCP-Response from the server.
Otherwise, if the packet containing the Confirm options gets dropped in the
network, the connection aborts due to undefined feature negotiation state.
Thanks to Leandro Melo de Sales who reported a bug in an earlier revision
of the patch set, resulting from not retransmitting the Confirm options.
The patch now ensures that the client feature-negotiation queue is flushed only
when entering the OPEN state. Since confirmed Change options are removed as
soon as they are confirmed (in the DCCP-Response), this ensures that Confirm
options are retransmitted.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
This patch provides the post-processing of feature negotiation state, after
the negotiation has completed.
To this purpose, handlers are used and added to the dccp_feat_table. Each
handler is passed a boolean flag whether the RX or TX side of the feature
is meant.
Several handlers are provided already, new handlers can easily be added.
The initialisation is now fully dynamic, i.e. CCIDs are activated only
after the feature negotiation. The integration of this dynamic activation
is done in the subsequent patches.
Thanks to Wei Yongjun for pointing out the necessity of skipping over empty
Confirm options while copying the negotiated feature values.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Analogous to the previous patch, this adds code to interpret incoming Confirm
feature-negotiation options. Both functions operate on the feature-negotiation
list of either the request_sock (server) or the dccp_sock (client).
Thanks to Wei Yongjun for pointing out that it is overly restrictive to check
the entire list of confirmed SP values.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
This adds/replaces code for processing incoming ChangeL/R options.
The main difference is that:
* mandatory FN options are now interpreted inside the function
(there are too many individual cases to do this externally);
* the function returns an appropriate Reset code or 0,
which is then used to fill in the data for the Reset packet.
Old code, which is no longer used or referenced, has been removed.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
This provides two functions to
* reconcile preference lists (with appropriate return codes) and
* reorder the preference list if successful reconciliation changed the
preferred value.
The patch also removes the old code for processing SP/NN Change options, since
new code to process these is mostly there already; related references have been
commented out.
The code for processing Change options follows in the next patch.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
The patch implements insertion of feature negotiation at the server (listening
and request socket) and the client (connecting socket).
In dccp_insert_options(), several statements have been grouped together now
to achieve (I hope) better efficiency by reducing the number of tests each
packet has to go through:
- Ack Vectors are sent if the packet is neither a Data or a Request packet;
- a previous issue is corrected - feature negotiation options are allowed
on DataAck packets (5.8).
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
This patch replaces the earlier insertion routine from options.c, so that
code specific to feature negotiation can remain in feat.c. This is possible
by calling a function already existing in options.c.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
The patch extends existing code:
* Confirm options divide into the confirmed value plus an optional preference
list for SP values. Previously only the preference list was echoed for SP
values, now the confirmed value is added as per RFC 4340, 6.1;
* length and sanity checks are added to avoid illegal memory (or NULL) access.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Support for Mandatory options is provided by this patch, which will
be used by subsequent feature-negotiation patches.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This extends the scope of two available functions, encode|decode_value_var,
to work up to 6 (8) bytes, to match maximum requirements in the RFC.
These functions are going to be used both by general option processing and
feature negotiation code, hence declarations have been put into feat.h.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This provides function to query the current TX/RX CCID dynamically, without
reliance on the minisock value, using dynamic information available in the
currently loaded CCID module.
This query function is then used to
(a) provide the getsockopt part for getting/setting CCIDs via sockopts;
(b) replace the current test for "which CCID is in use" in probe.c.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
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.
Note on the maximum number of CCIDs that can be registered:
-----------------------------------------------------------
The maximum number of CCIDs that can be registered on the socket is constrained
by the space in a Confirm/Change feature negotiation option.
The space in these in turn depends on the size of header options as defined
in RFC 4340, 5.8. Since this is a recurring constant, it has been moved from
ackvec.h into linux/dccp.h, clarifying its purpose.
Relative to this size, the maximum number of CCID identifiers that can be
present in a Confirm option (which always consumes 1 byte more than a Change
option, cf. 6.1) is 2 bytes less than the maximum TLV size: one for the
CCID-feature-type and one for the selected value.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
This splits the setsockopt calls into two groups, depending on whether an
integer argument (val) is required and whether routines being called do
their own locking.
Some options (such as setting the CCID) use u8 rather than int, so that for
these the test with regard to integer-sizeof can not be used.
The second switch-case statement now only has those statements which need
locking and which make use of `val'.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Reviewed-by: Eugene Teo <eugeneteo@kernel.sg>
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 <gerrit@erg.abdn.ac.uk>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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 <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
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 <gerrit@erg.abdn.ac.uk>
This adds a hook to resolve features whose value depends on the choice of
CCID. It is done at the server since it can only be done after the CCID
values have been negotiated; i.e. the client will add its CCID preference
list on the Change options sent in the Request, which will be reconciled
with the local preference list of the server.
The concept is documented on
http://www.erg.abdn.ac.uk/users/gerrit/dccp/notes/feature_negotiation/\
implementation_notes.html#ccid_dependencies
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
This provides a missing link in the code chain, as several features implicitly
depend and/or rely on the choice of CCID. Most notably, this is the Send Ack Vector
feature, but also Ack Ratio and Send Loss Event Rate (also taken care of).
For Send Ack Vector, the situation is as follows:
* since CCID2 mandates the use of Ack Vectors, there is no point in allowing
endpoints which use CCID2 to disable Ack Vector features such a connection;
* a peer with a TX CCID of CCID2 will always expect Ack Vectors, and a peer
with a RX CCID of CCID2 must always send Ack Vectors (RFC 4341, sec. 4);
* for all other CCIDs, the use of (Send) Ack Vector is optional and thus
negotiable. However, this implies that the code negotiating the use of Ack
Vectors also supports it (i.e. is able to supply and to either parse or
ignore received Ack Vectors). Since this is not the case (CCID-3 has no Ack
Vector support), the use of Ack Vectors is here disabled, with a comment
in the source code.
An analogous consideration arises for the Send Loss Event Rate feature,
since the CCID-3 implementation does not support the loss interval options
of RFC 4342. To make such use explicit, corresponding feature-negotiation
options are inserted which signal the use of the loss event rate option,
as it is used by the CCID3 code.
Lastly, the values of the Ack Ratio feature are matched to the choice of CCID.
The patch implements this as a function which is called after the user has
made all other registrations for changing default values of features.
The table is variable-length, the reserved (and hence for feature-negotiation
invalid, confirmed by considering section 19.4 of RFC 4340) feature number `0'
is used to mark the end of the table.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
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 <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Two registration routines, for SP and NN features, are provided by this patch,
replacing a previous routine which was used for both feature types.
These are internal-only routines and therefore start with `__feat_register'.
It further exports the known limits of Sequence Window and Ack Ratio as symbolic
constants.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
This patch starts the new implementation of feature negotiation:
1. Although it is theoretically possible to perform feature negotiation at any
time (and RFC 4340 supports this), in practice this is prohibitively complex,
as it requires to put traffic on hold for each new negotiation.
2. As a byproduct of restricting feature negotiation to connection setup, the
feature-negotiation retransmit timer is no longer required. This part is now
mapped onto the protocol-level retransmission.
Details indicating why timers are no longer needed can be found on
http://www.erg.abdn.ac.uk/users/gerrit/dccp/notes/feature_negotiation/\
implementation_notes.html
This patch disables anytime negotiation, subsequent patches work out full
feature negotiation support for connection setup.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
This inserts the required de-allocation routines for memory allocated by
feature negotiation in the socket destructors, replacing dccp_feat_clean()
in one instance.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
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 <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
This adds list fields and list management functions for the new feature
negotiation implementation. The new code is kept in parallel to the old
code, until removed at the end of the patch set.
Thanks to Arnaldo for suggestions to improve the code.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
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 <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
This patch prepares for the new and extended feature-negotiation routines.
The following feature-negotiation data structures are provided:
* a container for the various (SP or NN) values,
* symbolic state names to track feature states,
* an entry struct which holds all current information together,
* elementary functions to fill in and process these structures.
Entry structs are arranged as FIFO for the following reason: RFC 4340 specifies
that if multiple options of the same type are present, they are processed in the
order of their appearance in the packet; which means that this order needs to be
preserved in the local data structure (the later insertion code also respects
this order).
The struct list_head has been chosen for the following reasons: the most
frequent operations are
* add new entry at tail (when receiving Change or setting socket options);
* delete entry (when Confirm has been received);
* deep copy of entire list (cloning from listening socket onto request socket).
The NN value has been set to 64 bit, which is a currently sufficient upper limit
(Sequence Window feature has 48 bit).
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
The BUG_ON(w_tot == 0) only holds if there is no more than 1 loss interval in
the loss history. If there is only a single loss interval, the calc_i_mean()
routine need in fact not be called (RFC 3448, 6.3.1).
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
This sets the sysfs permissions so that root can toggle the `debug'
parameter available for nearly every DCCP module. This is useful
since there are various module inter-dependencies. The debug flag
can now be toggled at runtime using
echo 1 > /sys/module/dccp/parameters/dccp_debug
echo 1 > /sys/module/dccp_ccid2/parameters/ccid2_debug
echo 1 > /sys/module/dccp_ccid3/parameters/ccid3_debug
echo 1 > /sys/module/dccp_tfrc_lib/parameters/tfrc_debug
The last is not very useful yet, since no code at the moment calls
the tfrc_debug() macro.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
dccp_disconnect() can be called due to several reasons:
1. when the connection setup failed (inet_stream_connect());
2. when shutting down (inet_shutdown(), inet_csk_listen_stop());
3. when aborting the connection (dccp_close() with 0 linger time).
In case (1) the write queue is empty. This patch empties the write queue,
if in case (2) or (3) it was not yet empty.
This avoids triggering the write-queue BUG_TRAP in sk_stream_kill_queues()
later on.
It also seems natural to do: when breaking an association, to delete all
packets that were originally intended for the soon-disconnected end (compare
with call to tcp_write_queue_purge in tcp_disconnect()).
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
This updates the use of the `out_invalid_option' label, which produces a
Reset (code 5, "Option Error"), to fill in the Data1...Data3 fields as
specified in RFC 4340, 5.6.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
This updates the option-parsing code with regard to RFC 4340, 5.8:
"[..] options with nonsensical lengths (length byte less than two or more
than the remaining space in the options portion of the header) MUST be
ignored, and any option space following an option with nonsensical length
MUST likewise be ignored."
Hence in the following cases erratic options will be ignored:
1. The type byte of a multi-byte option is the last byte of the header
options (i.e. effective option length of 1).
2. The value of the length byte is less than the minimum 2. This has been
changed from previously 3: although no multi-byte option with a length
less than 3 yet exists (cf. table 3 in 5.8), a length of 2 is valid.
(The switch-statement in dccp_parse has further per-option length checks.)
3. The option length exceeds the length of the remaining option space.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
RFC4340 states that if a packet is received with an option error (such as a
Mandatory Option as the last byte of the option list), the endpoint should
repond with a Reset.
In the LISTEN and RESPOND states, the endpoint correctly reponds with Reset,
while in the REQUEST/OPEN states, packets with option errors are just ignored.
The packet sequence is as follows:
Case 1:
Endpoint A Endpoint B
(CLOSED) (CLOSED)
<---------------- REQUEST
RESPONSE -----------------> (*1)
(with invalid option)
<---------------- RESET
(with Reset Code 5, "Option Error")
(*1) currently just ignored, no Reset is sent
Case 2:
Endpoint A Endpoint B
(OPEN) (OPEN)
DATA-ACK -----------------> (*2)
(with invalid option)
<---------------- RESET
(with Reset Code 5, "Option Error")
(*2) currently just ignored, no Reset is sent
This patch fixes the problem, by generating a Reset instead of silently
ignoring option errors.
Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6:
bnx2x: Accessing un-mapped page
ath9k: Fix TX control flag use for no ACK and RTS/CTS
ath9k: Fix TX status reporting
iwlwifi: fix STATUS_EXIT_PENDING is not set on pci_remove
iwlwifi: call apm stop on exit
iwlwifi: fix Tx cmd memory allocation failure handling
iwlwifi: fix rx_chain computation
iwlwifi: fix station mimo power save values
iwlwifi: remove false rxon if rx chain changes
iwlwifi: fix hidden ssid discovery in passive channels
iwlwifi: W/A for the TSF correction in IBSS
netxen: Remove workaround for chipset quirk
pcnet-cs, axnet_cs: add new IDs, remove dup ID with less info
ixgbe: initialize interrupt throttle rate
net/usb/pegasus: avoid hundreds of diagnostics
tipc: Don't use structure names which easily globally conflict.
Andrew Morton reported a build failure on sparc32, because TIPC
uses names like "struct node" and there is a like named data
structure defined in linux/node.h
This just regexp replaces "struct node*" to "struct tipc_node*"
to avoid this and any future similar problems.
Signed-off-by: David S. Miller <davem@davemloft.net>
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6:
ipsec: Fix deadlock in xfrm_state management.
ipv: Re-enable IP when MTU > 68
net/xfrm: Use an IS_ERR test rather than a NULL test
ath9: Fix ath_rx_flush_tid() for IRQs disabled kernel warning message.
ath9k: Incorrect key used when group and pairwise ciphers are different.
rt2x00: Compiler warning unmasked by fix of BUILD_BUG_ON
mac80211: Fix debugfs union misuse and pointer corruption
wireless/libertas/if_cs.c: fix memory leaks
orinoco: Multicast to the specified addresses
iwlwifi: fix 64bit platform firmware loading
iwlwifi: fix apm_stop (wrong bit polarity for FLAG_INIT_DONE)
iwlwifi: workaround interrupt handling no some platforms
iwlwifi: do not use GFP_DMA in iwl_tx_queue_init
net/wireless/Kconfig: clarify the description for CONFIG_WIRELESS_EXT_SYSFS
net: Unbreak userspace usage of linux/mroute.h
pkt_sched: Fix locking of qdisc_root with qdisc_root_sleeping_lock()
ipv6: When we droped a packet, we should return NET_RX_DROP instead of 0
Ever since commit 4c563f7669
("[XFRM]: Speed up xfrm_policy and xfrm_state walking") it is
illegal to call __xfrm_state_destroy (and thus xfrm_state_put())
with xfrm_state_lock held. If we do, we'll deadlock since we
have the lock already and __xfrm_state_destroy() tries to take
it again.
Fix this by pushing the xfrm_state_put() calls after the lock
is dropped.
Signed-off-by: David S. Miller <davem@davemloft.net>
Removes all _nested_compat() functions from the API. The prio qdisc
no longer requires them and netem has its own format anyway. Their
existance is only confusing.
Resend: Also remove the wrapper macro.
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Re-enable IP when the MTU gets back to a valid size.
This patch just checks if the in_dev is NULL on a NETDEV_CHANGEMTU event
and if MTU is valid (bigger than 68), then re-enable in_dev.
Also a function that checks valid MTU size was created.
Signed-off-by: Breno Leitao <leitao@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In case of error, the function xfrm_bundle_create returns an ERR
pointer, but never returns a NULL pointer. So a NULL test that comes
after an IS_ERR test should be deleted.
The semantic match that finds this problem is as follows:
(http://www.emn.fr/x-info/coccinelle/)
// <smpl>
@match_bad_null_test@
expression x, E;
statement S1,S2;
@@
x = xfrm_bundle_create(...)
... when != x = E
* if (x != NULL)
S1 else S2
// </smpl>
Signed-off-by: Julien Brunel <brunel@diku.dk>
Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: David S. Miller <davem@davemloft.net>
debugfs union in struct ieee80211_sub_if_data is misused by including a
common default_key dentry as a union member. This ends occupying the same
memory area with the first dentry in other union members (structures;
usually drop_unencrypted). Consequently, debugfs operations on
default_key symlinks and drop_unencrypted entry are using the same
dentry pointer even though they are supposed to be separate ones. This
can lead to removing entries incorrectly or potentially leaving
something behind since one of the dentry pointers gets lost.
Fix this by moving the default_key dentry to a new struct
(common_debugfs) that contains dentries (more to be added in future)
that are shared by all vif types. The debugfs union must only be used
for vif type-specific entries to avoid this type of pointer corruption.
Signed-off-by: Jouni Malinen <jouni.malinen@atheros.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Current setup with hal and NetworkManager will fail to work
without newest hal version with this config option disabled.
Although this will solve itself by time, at the moment it is
dishonest to say that we don't know any software that uses it,
if there are many many people relying on old hal versions.
Signed-off-by: Florian Mickler <florian@mickler.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
* 'for-2.6.27' of git://linux-nfs.org/~bfields/linux:
nfsd: fix buffer overrun decoding NFSv4 acl
sunrpc: fix possible overrun on read of /proc/sys/sunrpc/transports
nfsd: fix compound state allocation error handling
svcrdma: Fix race between svc_rdma_recvfrom thread and the dto_tasklet
Vegard Nossum reported
----------------------
> I noticed that something weird is going on with /proc/sys/sunrpc/transports.
> This file is generated in net/sunrpc/sysctl.c, function proc_do_xprt(). When
> I "cat" this file, I get the expected output:
> $ cat /proc/sys/sunrpc/transports
> tcp 1048576
> udp 32768
> But I think that it does not check the length of the buffer supplied by
> userspace to read(). With my original program, I found that the stack was
> being overwritten by the characters above, even when the length given to
> read() was just 1.
David Wagner added (among other things) that copy_to_user could be
probably used here.
Ingo Oeser suggested to use simple_read_from_buffer() here.
The conclusion is that proc_do_xprt doesn't check for userside buffer
size indeed so fix this by using Ingo's suggestion.
Reported-by: Vegard Nossum <vegard.nossum@gmail.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
CC: Ingo Oeser <ioe-lkml@rameria.de>
Cc: Neil Brown <neilb@suse.de>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Greg Banks <gnb@sgi.com>
Cc: Tom Tucker <tom@opengridcomputing.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Use qdisc_root_sleeping_lock() instead of qdisc_root_lock() where
appropriate. The only difference is while dev is deactivated, when
currently we can use a sleeping qdisc with the lock of noop_qdisc.
This shouldn't be dangerous since after deactivation root lock could
be used only by gen_estimator code, but looks wrong anyway.
Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
rfkill_mutex and rfkill->mutex are too easy to confuse with each other.
Rename rfkill_mutex to rfkill_global_mutex, so that they are easier to tell
apart with just one glance.
Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Acked-by: Ivo van Doorn <IvDoorn@gmail.com>
Cc: Michael Buesch <mb@bu3sch.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
BUG_ON() and WARN() the heck out of buggy drivers calling into the rfkill
subsystem.
Also switch from WARN_ON(1) to the new descriptive WARN().
Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Acked-by: Ivo van Doorn <IvDoorn@gmail.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Trivial patch adding a missing line break on
rfkill_claim_show().
Signed-off-by: Felipe Balbi <felipe.balbi@nokia.com>
Acked-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Acked-by: Ivo van Doorn <IvDoorn@gmail.co>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Switch sysfs parsing to something that actually works properly.
Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Acked-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Allow userspace (e.g., hostapd) to set HT capabilities for associated
STAs. This is based on a patch from Zhu Yi <yi.zhu@intel.com> (only
the NL80211_ATTR_HT_CAPABILITY for NEW_STA part is included here).
Signed-off-by: Jouni Malinen <jouni.malinen@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Bit 4-5 of DSCP should not be considered by classify_d1. The
802.11 QoS Priority field is only depending on the precedence level.
Signed-off-by: Daniel Wagner <wagi@monom.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Clean up and extend scan result processing by storing all the IEs from
Beacon/Probe Response frames in a single block instead of allocating
memory for each specific IE separately. This removes lot of unnecessary
code and automatically supports reporting of new IEs (e.g., IEEE
802.11r) into user space without need to manually extend mac80211
scanning code whenever a new protocol adds IE(s).
Signed-off-by: Jouni Malinen <jouni.malinen@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This change adds a new cfg80211 command, NL80211_CMD_SET_BSS, to allow
AP mode BSS parameters to be changed from user space (e.g., hostapd).
The drivers using mac80211 are expected to be modified with separate
changes to use the new BSS info parameter for short slot time in the
bss_info_changed() handler.
Signed-off-by: Jouni Malinen <jouni.malinen@atheros.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Otherwise, drivers are required to keep track of the sequence numbers
themselves, and they really shouldn't be since we already do it for
them. I'll fix the race once we figure out how this code should work
at all, it's currently disabled.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
When scanning route cache hash table, we can avoid taking locks for
empty buckets. Both /proc/net/rt_cache and NETLINK RTM_GETROUTE
interface are taken into account.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
On most systems most of the TCP established/time-wait hash buckets are empty.
When walking the hash table for /proc/net/tcp their read locks would
always be aquired just to find out they're empty. This patch changes the code
to check first if the buckets have any entries before taking the lock, which
is much cheaper than taking a lock. Since the hash tables are large
this makes a measurable difference on processing /proc/net/tcp,
especially on architectures with slow read_lock (e.g. PPC)
On a 2GB Core2 system time cat /proc/net/tcp > /dev/null (with a mostly
empty hash table) goes from 0.046s to 0.005s.
On systems with slower atomics (like P4 or POWER4) or larger hash tables
(more RAM) the difference is much higher.
This can be noticeable because there are some daemons around who regularly
scan /proc/net/tcp.
Original idea for this patch from Marcus Meissner, but redone by me.
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
The number of identifiers needs to be checked against the option
length. Also, the identifier index provided needs to be verified
to make sure that it doesn't exceed the bounds of the array.
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The bonds check to prevent buffer overlflow was not exactly
right. It still allowed overflow of up to 8 bytes which is
sizeof(struct sctp_authkey).
Since optlen is already checked against the size of that struct,
we are guaranteed not to cause interger overflow either.
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The size of the TCP header is miscalculated when the window scale ends
up being 0. Additionally, this can be induced by sending a SYN to a
passive open port with a window scale option with value 0.
Signed-off-by: Philip Love <love_phil@emc.com>
Signed-off-by: Adam Langley <agl@imperialviolet.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
While passing a qdisc root lock to gen_new_estimator() and
gen_replace_estimator() dev could be deactivated or even before
grafting proper root qdisc as qdisc_sleeping (e.g. qdisc_create), so
using qdisc_root_lock() is not enough. This patch adds
qdisc_root_sleeping_lock() for this, plus additional checks, where
necessary.
Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
These pointers are RCU protected, so proper primitives should be used.
Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
During dev_graft_qdisc() dev is deactivated, so qdisc_root_lock()
returns wrong lock of noop_qdisc instead of qdisc_sleeping.
Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
The BUG_ON(w_tot == 0) only holds if there is no more than 1 loss interval in
the loss history. If there is only a single loss interval, the calc_i_mean()
routine need in fact not be called (RFC 3448, 6.3.1).
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
This sets the sysfs permissions so that root can toggle the `debug'
parameter available for nearly every DCCP module. This is useful
since there are various module inter-dependencies. The debug flag
can now be toggled at runtime using
echo 1 > /sys/module/dccp/parameters/dccp_debug
echo 1 > /sys/module/dccp_ccid2/parameters/ccid2_debug
echo 1 > /sys/module/dccp_ccid3/parameters/ccid3_debug
echo 1 > /sys/module/dccp_tfrc_lib/parameters/tfrc_debug
The last is not very useful yet, since no code at the moment calls
the tfrc_debug() macro.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
dccp_disconnect() can be called due to several reasons:
1. when the connection setup failed (inet_stream_connect());
2. when shutting down (inet_shutdown(), inet_csk_listen_stop());
3. when aborting the connection (dccp_close() with 0 linger time).
In case (1) the write queue is empty. This patch empties the write queue,
if in case (2) or (3) it was not yet empty.
This avoids triggering the write-queue BUG_TRAP in sk_stream_kill_queues()
later on.
It also seems natural to do: when breaking an association, to delete all
packets that were originally intended for the soon-disconnected end (compare
with call to tcp_write_queue_purge in tcp_disconnect()).
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
This updates the use of the `out_invalid_option' label, which produces a
Reset (code 5, "Option Error"), to fill in the Data1...Data3 fields as
specified in RFC 4340, 5.6.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
This updates the option-parsing code with regard to RFC 4340, 5.8:
"[..] options with nonsensical lengths (length byte less than two or more
than the remaining space in the options portion of the header) MUST be
ignored, and any option space following an option with nonsensical length
MUST likewise be ignored."
Hence in the following cases erratic options will be ignored:
1. The type byte of a multi-byte option is the last byte of the header
options (i.e. effective option length of 1).
2. The value of the length byte is less than the minimum 2. This has been
changed from previously 3: although no multi-byte option with a length
less than 3 yet exists (cf. table 3 in 5.8), a length of 2 is valid.
(The switch-statement in dccp_parse has further per-option length checks.)
3. The option length exceeds the length of the remaining option space.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
RFC4340 states that if a packet is received with an option error (such as a
Mandatory Option as the last byte of the option list), the endpoint should
repond with a Reset.
In the LISTEN and RESPOND states, the endpoint correctly reponds with Reset,
while in the REQUEST/OPEN states, packets with option errors are just ignored.
The packet sequence is as follows:
Case 1:
Endpoint A Endpoint B
(CLOSED) (CLOSED)
<---------------- REQUEST
RESPONSE -----------------> (*1)
(with invalid option)
<---------------- RESET
(with Reset Code 5, "Option Error")
(*1) currently just ignored, no Reset is sent
Case 2:
Endpoint A Endpoint B
(OPEN) (OPEN)
DATA-ACK -----------------> (*2)
(with invalid option)
<---------------- RESET
(with Reset Code 5, "Option Error")
(*2) currently just ignored, no Reset is sent
This patch fixes the problem, by generating a Reset instead of silently
ignoring option errors.
Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
After integrating ESP into ip_vs_proto_ah, rename it (and the references to
it) to ip_vs_proto_ah_esp.c and delete the old ip_vs_proto_esp.c.
Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
Rename all ah_* functions to ah_esp_* (and adjust comments). Move ESP
protocol definition into ip_vs_proto_ah.c and remove all usage of
ip_vs_proto_esp.c.
Make the compilation of ip_vs_proto_ah.c dependent on a new config
variable, IP_VS_PROTO_AH_ESP, which is selected either by
IP_VS_PROTO_ESP or IP_VS_PROTO_AH. Only compile the selected protocols'
structures within this file.
Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
The association request includes a list of supported data rates.
802.11b: 4 supported rates.
802.11g: 12 (8 + 4) supported rates.
802.11a: 8 supported rates.
The rates tag of the assoc request has room for only 8 rates. In case of
802.11g an extended rate tag is appended. However in net/wireless/mlme.c
an extended (empty) rate tag is also appended if the number of rates is
exact 8. This empty (length=0) extended rates tag causes some APs to
deny association with code 18 (unsupported rates). These APs include my
ZyXEL G-570U, and according to Tomas Winkler som Cisco APs.
'If count == 8' has been used to check for the need for an extended rates
tag. But count would also be equal to 8 if the for loop exited because of
no more supported rates. Therefore a check for count being less than
rates_len would seem more correct.
Thanks to:
* Dan Williams for newbie guidance
* Tomas Winkler for confirming the problem
Signed-off-by: Jan-Espen Pettersen <sigsegv@radiotube.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Previous version was using incorrect union structures for non-AP
interfaces when adding and removing max_ratectrl_rateidx and
force_unicast_rateidx entries. Depending on the vif type, this ended
up in corrupting debugfs entries since the dentries inside different
union structures ended up going being on top of eachother.. As the
end result, debugfs files were being left behind with references to
freed data (instant kernel oops on access) and directories were not
removed properly when unloading mac80211 drivers. This patch fixes
those issues by using only a single union structure based on the vif
type.
Signed-off-by: Jouni Malinen <jouni.malinen@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
In the function mesh_table_grow, it is the new table not the argument table
that should be freed if the function fails (cf commit
bd9b448f4c)
The semantic match that detects this problem is as follows:
(http://www.emn.fr/x-info/coccinelle/)
// <smpl>
@r exists@
local idexpression x;
expression E,f;
position p1,p2,p3;
identifier l;
statement S;
@@
x = mesh_table_alloc@p1(...)
...
if (x == NULL) S
... when != E = x
when != mesh_table_free(x)
goto@p2 l;
... when != E = x
when != f(...,x,...)
when any
(
return \(0\|x\);
|
return@p3 ...;
)
@script:python@
p1 << r.p1;
p2 << r.p2;
p3 << r.p3;
@@
print "%s: call on line %s not freed or saved before return on line %s via line %s" % (p1[0].file,p1[0].line,p3[0].line,p2[0].line)
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
The previous code was using IWEVCUSTOM to report IEs from AssocReq and
AssocResp frames into user space. This can easily hit the 256 byte
limit (IW_CUSTOM_MAX) with APs that include number of vendor IEs in
AssocResp. This results in the event message not being sent and dmesg
showing "wlan0 (WE) : Wireless Event too big (366)" type of errors.
Convert mac80211 to use IWEVASSOCREQIE/IWEVASSOCRESPIE to avoid the
issue of being unable to send association IEs as wireless events. These
newer event types use binary encoding and larger maximum size
(IW_GENERIC_IE_MAX = 1024), so the likelyhood of not being able to send
the IEs is much smaller than with IWEVCUSTOM. As an extra benefit, the
code is also quite a bit simpler since there is no need to allocate an
extra buffer for hex encoding.
Signed-off-by: Jouni Malinen <jouni.malinen@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Trivial patch adding a missing line break on
rfkill_claim_show().
Signed-off-by: Felipe Balbi <felipe.balbi@nokia.com>
Acked-by: Ivo van Doorn <IvDoorn@gmail.co>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Braino: net.ipv6 in ipv6 skeleton has no business in rotable
class
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
net.ipv4.neigh should be a part of skeleton to avoid ordering problems
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
The structure used for SCTP_AUTH_KEY option contains a
length that needs to be verfied to prevent buffer overflow
conditions. Spoted by Eugene Teo <eteo@redhat.com>.
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This fixes a problem spotted with zebra, but not sure if it is
necessary a kernel problem. With IPV6 when an address is added to an
interface, Zebra creates a duplicate RIB entry, one as a connected
route, and other as a kernel route.
When an address is added to an interface the RTN_NEWADDR message
causes Zebra to create a connected route. In IPV4 when an address is
added to an interface a RTN_NEWROUTE message is set to user space with
the protocol RTPROT_KERNEL. Zebra ignores these messages, because it
already has the connected route.
The problem is that route created in IPV6 has route protocol ==
RTPROT_BOOT. Was this a design decision or a bug? This fixes it. Same
patch applies to both net-2.6 and stable.
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Some duplicated code lying around. Located with my suffix tree
tool.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
Large block of code duplication removed.
Sadly, the return value thing is a bit tricky here but it
seems the most sensible way to return positive from validator
on success rather than negative.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds a direct probe request as first step in the association
flow if data we have is not up to date. Motivation of this step is to make
sure that the bss information we have is correct, since last scan could
have been done a while ago, and beacons do not fully answer this need as
there are potential differences between them and probe responses (e.g.
WMM parameter element)
Signed-off-by: Ron Rindjunsky <ron.rindjunsky@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This patch fixes noticed problem in noisy environments of 50+ APs
that scan fails to find the requested AP on first try, which
leads to connection refusal. second scan has empirically proven to fix
this problem in almost all cases.
Signed-off-by: Ron Rindjunsky <ron.rindjunsky@intel.com>
Signed-off-by: Esti Kummer <ester.kummer@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This patch move add STA_MLME to station mlme state defines.
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This patch moves filtering statement from ieee80211_rx_bss_info
which is called for both beacon and probe to ieee80211_rx_mgmt_probe_resp
and save few cycles in beacon parsing.
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This patch replaces net_device arguments to mac80211 internal functions
with ieee80211_{local,sub_if_data} as appropriate.
It also does the same for many 802.11s mesh functions, and changes the
mesh path table to be indexed on sub_if_data rather than net_device.
If the mesh part needs to be a separate patch let me know, but since
mesh uses a lot of mac80211 functions which were being converted anyway,
the changes go hand-in-hand somewhat.
This patch probably does not convert all the functions which could be
converted, but it is a large chunk and followup patches will be
provided.
Signed-off-by: Jasper Bryant-Greene <jasper@amiton.co.nz>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
ETH_P_PAE belongs in if_ether.h with the other ETH_P_* definitions. This
patch moves it there.
Signed-off-by: Jasper Bryant-Greene <jasper@amiton.co.nz>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
While it is interesting to not add last-enum-markers because it allows gcc
to warn us of switch() statements missing a valid state, we really should
be handling memory corruption on a rfkill state with default clauses,
anyway.
So add RFKILL_STATE_MAX and use it where applicable. It makes for safer
code in the long run.
Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Acked-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
rfkill is not a small, mere detail in wireless support. Once it starts
supporting rfkill and users start counting on that support, a wireless
device is at risk of operating in dangerous conditions should rfkill
support fail to properly activate.
Therefore, add the required __must_check annotations on some key functions
of the rfkill API, for which the wireless drivers absolutely MUST handle
the failure mode safely in order to avoid a potentially dangerous situation
where the wireless transmitter is left enabled when the user don't want it
to.
Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Acked-by: Ivo van Doorn <IvDoorn@gmail.com>
Cc: Matthew Garrett <mjg@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Add a second set of global states, "rfkill_default_states", to track the
state that will be used when the first rfkill class of a given type is
registered, and also to save "undo" information when rfkill_epo is called.
Add a new exported function, rfkill_set_default(), which can be used by
platform drivers to restore radio state saved by the platform across
reboots or shutdown.
Also, fix rfkill_epo to properly update rfkill_states, but still preserve a
copy of the state so that we can undo the effect of rfkill_epo later if we
want to. Add rfkill_restore_states() to restore rfkill_states from the
copy.
Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Acked-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Detect and abort with -EEXIST if rfkill_register is called twice on the
same rfkill struct. And WARN_ON(it) for good measure.
While at it, flag when we are adding the first switch of a type, we will
need that information later.
Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Acked-by: Ivo van Doorn <IvDoorn@gmail.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Originally by Johannes Berg. This patch adds support for devices that do not
report their MAC address until the firmware is loaded. While the address is not
known, a multicast on is used.
Signed-off-by: Luis Carlos Cobo <luisca@cozybit.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Remove the last users of the rx/tx_data->fc data members and use the
le16 frame_control from the header directly.
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
