02 Mar, 2009
2 commits
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This fixes a problem caused by the overlap of the connection-setup and
established-state phases of DCCP connections.During connection setup, the client retransmits Confirm Feature-Negotiation
options until a response from the server signals that it can move from the
half-established PARTOPEN into the OPEN state, whereupon the connection is
fully established on both ends (RFC 4340, 8.1.5).However, since the client may already send data while it is in the PARTOPEN
state, consequences arise for the Maximum Packet Size: the problem is that the
initial option overhead is much higher than for the subsequent established
phase, as it involves potentially many variable-length list-type options
(server-priority options, RFC 4340, 6.4).Applying the standard MPS is insufficient here: especially with larger
payloads this can lead to annoying, counter-intuitive EMSGSIZE errors.On the other hand, reducing the MPS available for the established phase by
the added initial overhead is highly wasteful and inefficient.The solution chosen therefore is a two-phase strategy:
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 result is a higher utilisation of the available packet space for the data
transmission phase (established state) of a connection.The patch (over-)estimates the initial overhead to be 32*4 bytes -- commonly
seen values were around 90 bytes for initial feature-negotiation options.It uses sizeof(u32) to mean "aligned units of 4 bytes".
For consistency, another use of 4-byte alignment is adapted.Signed-off-by: Gerrit Renker
Signed-off-by: David S. Miller -
This patch resolves a long-standing FIXME to dynamically update the Maximum
Packet Size depending on actual options usage.It uses the flags set by the feature-negotiation infrastructure to compute
the required header option size.Most options are fixed-size, a notable exception are Ack Vectors (required
currently only by CCID-2). These can have any length between 3 and 1020
bytes. As a result of testing, 16 bytes (2 bytes for type/length plus 14 Ack
Vector cells) have been found to be sufficient for loss-free situations.There are currently no CCID-specific header options which may appear on data
packets, thus it is not necessary to define a corresponding CCID field as
suggested in the old comment.Further changes:
----------------
Adjusted the type of 'cur_mps' to match the unsigned return type of the
function.Signed-off-by: Gerrit Renker
Acked-by: Ian McDonald
Signed-off-by: David S. Miller
22 Jan, 2009
4 commits
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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 and
discussion with an earlier revision of this patch.Signed-off-by: Gerrit Renker
Acked-by: Ian McDonald
Signed-off-by: David S. Miller -
This patch takes care of initialising and type-checking sysctls
related to feature negotiation. Type checking is important since some
of the sysctls now directly impact the feature-negotiation process.The sysctls are initialised with the known default values for each
feature. For the type-checking the value constraints from RFC 4340
are used:* Sequence Window uses the specified Wmin=32, the maximum is ulong (4 bytes),
tested and confirmed that it works up to 4294967295 - for Gbps speed;
* Ack Ratio is between 0 .. 0xffff (2-byte unsigned integer);
* CCIDs are between 0 .. 255;
* request_retries, retries1, retries2 also between 0..255 for good measure;
* tx_qlen is checked to be non-negative;
* sync_ratelimit remains as before.Notes:
------
1. Die s@sysctl_dccp_feat@sysctl_dccp@g since the sysctls are now in feat.c.
2. As pointed out by Arnaldo, the pattern of type-checking repeats itself in
other places, sometimes with exactly the same kind of definitions (e.g.
"static int zero;"). It may be a good idea (kernel janitors?) to consolidate
type checking. For the sake of keeping the changeset small and in order not
to affect other subsystems, I have not strived to generalise here.Signed-off-by: Gerrit Renker
Acked-by: Ian McDonald
Signed-off-by: David S. Miller -
This adds full support for local/remote Sequence Window feature, from which the
* sequence-number-validity (W) and
* acknowledgment-number-validity (W') windows
derive as specified in RFC 4340, 7.5.3.Specifically, the following is contained in this patch:
* integrated new socket fields into dccp_sk;
* updated the update_gsr/gss routines with regard to these fields;
* updated handler code: the Sequence Window feature is located at the TX side,
so the local feature is meant if the handler-rx flag is false;
* the initialisation of `rcv_wnd' in reqsk is removed, since
- rcv_wnd is not used by the code anywhere;
- sequence number checks are not done in the LISTEN state (cf. 7.5.3);
- dccp_check_req checks the Ack number validity more rigorously;
* the `struct dccp_minisock' became empty and is now removed.Signed-off-by: Gerrit Renker
Acked-by: Ian McDonald
Signed-off-by: David S. Miller -
This initialises feature negotiation from two tables, which are in
turn are initialised from sysctls.As a novel feature, specifics of the implementation (e.g. that short
seqnos and ECN are not yet available) are advertised for robustness.Signed-off-by: Gerrit Renker
Acked-by: Ian McDonald
Signed-off-by: David S. Miller
11 Jan, 2009
2 commits
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Thanks to Wei and Arnaldo for pointing out the correct
new reference for CCID-3.Signed-off-by: Gerrit Renker
Signed-off-by: David S. Miller -
Removed the __exit annotation of tfrc_lib_exit(), in order to suppress the following section mismatch messages:
WARNING: net/dccp/dccp.o(.text+0xd9): Section mismatch in reference from the function ccid_cleanup_builtins() to the function .exit.text:tfrc_lib_exit()
The function ccid_cleanup_builtins() references a function in an exit section.
Often the function tfrc_lib_exit() has valid usage outside the exit section
and the fix is to remove the __exit annotation of tfrc_lib_exit.WARNING: net/dccp/dccp.o(.init.text+0x48): Section mismatch in reference from the function ccid_initialize_builtins() to the function .exit.text:tfrc_lib_exit()
The function __init ccid_initialize_builtins() references
a function __exit tfrc_lib_exit().
This is often seen when error handling in the init function
uses functionality in the exit path.
The fix is often to remove the __exit annotation of
tfrc_lib_exit() so it may be used outside an exit section.Signed-off-by: Leonardo Potenza
Acked-by: Arnaldo Carvalho de Melo
Acked-by: Gerrit Renker
Signed-off-by: David S. Miller
05 Jan, 2009
3 commits
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This patch integrates the TFRC library, which is a dependency of CCID-3 (and
CCID-4), with the new use of CCIDs in the DCCP module.Signed-off-by: Gerrit Renker
Signed-off-by: David S. Miller -
This patch cleans up after integrating the CCID modules and, in addition,
* moves the if/else cases from ccid_delete() into ccid_hc_{tx,rx}_delete();
* removes the 'gfp' argument to ccid_new() - since it is always gfp_any().Signed-off-by: Gerrit Renker
Signed-off-by: David S. Miller -
Based on Arnaldo's earlier patch, this patch integrates the standardised
CCID congestion control plugins (CCID-2 and CCID-3) of DCCP with dccp.ko:* enables a faster connection path by eliminating the need to always go
through the CCID registration lock;* updates the implementation to use only a single array whose size equals
the number of configured CCIDs instead of the maximum (256);* since the CCIDs are now fixed array elements, synchronization is no
longer needed, simplifying use and implementation.CCID-2 is suggested as minimum for a basic DCCP implementation (RFC 4340, 10);
CCID-3 is a standards-track CCID supported by RFC 4342 and RFC 5348.Signed-off-by: Gerrit Renker
Signed-off-by: David S. Miller
30 Dec, 2008
1 commit
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When we converted the protocol atomic counters such as the orphan
count and the total socket count deadlocks were introduced due to
the mismatch in BH status of the spots that used the percpu counter
operations.Based on the diagnosis and patch by Peter Zijlstra, this patch
fixes these issues by disabling BH where we may be in process
context.Reported-by: Jeff Kirsher
Tested-by: Ingo Molnar
Signed-off-by: Herbert Xu
Signed-off-by: David S. Miller
18 Dec, 2008
1 commit
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And thus when we try to use 'ss -danemi' on these sockets that have no
ccid blocks (data collected using systemtap after I fixed the problem):dccp_diag_get_info sk=0xffff8801220a3100, dp->dccps_hc_rx_ccid=0x0000000000000000, dp->dccps_hc_tx_ccid=0x0000000000000000
We get an OOPS:
mica.ghostprotocols.net login: BUG: unable to handle kernel NULL pointer
dereferenc0
IP: [] dccp_diag_get_info+0x82/0xc0 [dccp_diag]
PGD 12106f067 PUD 122488067 PMD 0
Oops: 0000 [#1] PREEMPTFix is trivial, and 'ss -d' is working again:
[root@mica ~]# ss -danemi
State Recv-Q Send-Q Local Address:Port Peer Address:Port
LISTEN 0 0 *:5001 *:*
ino:7288 sk:220a3100ffff8801
mem:(r0,w0,f0,t0) cwnd:0 ssthresh:0
[root@mica ~]#Signed-off-by: Arnaldo Carvalho de Melo
Signed-off-by: David S. Miller
08 Dec, 2008
7 commits
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This removes the use of the sysctl and the minisock variable for the Send Ack
Vector feature, as it now is handled fully dynamically via feature negotiation
(i.e. when CCID-2 is enabled, Ack Vectors are automatically enabled as per
RFC 4341, 4.).Using a sysctl in parallel to this implementation would open the door to
crashes, since much of the code relies on tests of the boolean minisock /
sysctl variable. Thus, this patch replaces all tests of typeif (dccp_msk(sk)->dccpms_send_ack_vector)
/* ... */
with
if (dp->dccps_hc_rx_ackvec != NULL)
/* ... */The dccps_hc_rx_ackvec is allocated by the dccp_hdlr_ackvec() when feature
negotiation concluded that Ack Vectors are to be used on the half-connection.
Otherwise, it is NULL (due to dccp_init_sock/dccp_create_openreq_child),
so that the test is a valid one.The activation handler for Ack Vectors is called as soon as the feature
negotiation has concluded at the
* server when the Ack marking the transition RESPOND => OPEN arrives;
* client after it has sent its ACK, marking the transition REQUEST => PARTOPEN.Adding the sequence number of the Response packet to the Ack Vector has been
removed, since
(a) connection establishment implies that the Response has been received;
(b) the CCIDs only look at packets received in the (PART)OPEN state, i.e.
this entry will always be ignored;
(c) it can not be used for anything useful - to detect loss for instance, only
packets received after the loss can serve as pseudo-dupacks.There was a FIXME to change the error code when dccp_ackvec_add() fails.
I removed this after finding out that:
* the check whether ackno < ISN is already made earlier,
* this Response is likely the 1st packet with an Ackno that the client gets,
* so when dccp_ackvec_add() fails, the reason is likely not a packet error.Signed-off-by: Gerrit Renker
Acked-by: Ian McDonald
Signed-off-by: David S. Miller -
Updating the NDP count feature is handled automatically now:
* for CCID-2 it is disabled, since the code does not use NDP counts;
* for CCID-3 it is enabled, as NDP counts are used to determine loss lengths.Allowing the user to change NDP values leads to unpredictable and failing
behaviour, since it is then possible to disable NDP counts even when they
are needed (e.g. in CCID-3).This means that only those user settings are sensible that agree with the
values for Send NDP Count implied by the choice of CCID. But those settings
are already activated by the feature negotiation (CCID dependency tracking),
hence this form of support is redundant.At startup the initialisation of the NDP count feature uses the default
value of 0, which is done implicitly by the zeroing-out of the socket when
it is allocated. If the choice of CCID or feature negotiation enables NDP
count, this will then be updated via the NDP activation handler.Signed-off-by: Gerrit Renker
Acked-by: Ian McDonald
Signed-off-by: David S. Miller -
The TX/RX CCIDs of the minisock are now redundant: similar to the Ack Vector
case, their value equals initially that of the sysctl, but at the end of
feature negotiation may be something different.The old interface removed by this patch thus has been replaced by the newer
interface to dynamically query the currently loaded CCIDs.Also removed are the constructors for the TX CCID and the RX CCID, since the
switch "rx non-rx" is done by the handler in minisocks.c (and the handler
is the only place in the code where CCIDs are loaded).Signed-off-by: Gerrit Renker
Acked-by: Ian McDonald
Signed-off-by: David S. Miller -
The code removed by this patch is no longer referenced or used, the added
lines update documentation and copyrights.Signed-off-by: Gerrit Renker
Acked-by: Ian McDonald
Signed-off-by: David S. Miller -
This integrates feature-activation in the client:
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 - changed to use the reset code supplied by dccp_parse_options().2. When feature negotiation fails, the socket should be marked as not usable,
so that the application is notified that an error occurred. This is achieved
by a new label 'unable_to_proceed': generating an error code of `Aborted',
setting the socket state to CLOSED, returning with ECOMM in sk_err.3. 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
Acked-by: Ian McDonald
Signed-off-by: David S. Miller -
This patch integrates the activation of features at the end of negotiation
into the server-side code.Note regarding the removal of 'const':
--------------------------------------
The 'const' attribute has been removed from 'dreq' since dccp_activate_values()
needs to operate on dreq's feature list. Part of the activation is to remove
those options from the list that have already been confirmed, hence it is not
purely read-only.Signed-off-by: Gerrit Renker
Acked-by: Ian McDonald
Signed-off-by: David S. Miller -
This first patch out of three replaces the hardcoded default settings with
initialisation code for the dynamic feature negotiation.The patch also 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.Note on retransmitting Confirm options:
---------------------------------------
Implementation experience showed that it is necessary to retransmit Confirm
options. Thanks to Leandro Melo de Sales who reported a bug in an earlier
revision of the patch set, resulting from not retransmitting these options.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.Signed-off-by: Gerrit Renker
Acked-by: Ian McDonald
Signed-off-by: David S. Miller
06 Dec, 2008
1 commit
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Signed-off-by: Ilpo Järvinen
Signed-off-by: David S. Miller
02 Dec, 2008
6 commits
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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
Acked-by: Ian McDonald
Signed-off-by: David S. Miller -
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
Acked-by: Ian McDonald
Signed-off-by: David S. Miller -
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
Signed-off-by: David S. Miller -
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
Acked-by: Ian McDonald
Signed-off-by: David S. Miller -
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 (it is hoped) 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
Acked-by: Ian McDonald
Signed-off-by: David S. Miller -
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
Acked-by: Ian McDonald
Signed-off-by: David S. Miller
26 Nov, 2008
3 commits
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Instead of using one atomic_t per protocol, use a percpu_counter
for "orphan_count", to reduce cache line contention on
heavy duty network servers.Signed-off-by: Eric Dumazet
Signed-off-by: David S. Miller -
Pass netns to xfrm_lookup()/__xfrm_lookup(). For that pass netns
to flow_cache_lookup() and resolver callback.Take it from socket or netdevice. Stub DECnet to init_net.
Signed-off-by: Alexey Dobriyan
Signed-off-by: David S. Miller -
this warning:
net/dccp/options.c: In function ‘dccp_parse_options’:
net/dccp/options.c:67: warning: ‘value’ may be used uninitialized in this functionis a bogus GCC warning. The compiler does not recognize the relation
between "value" and "mandatory" variables: the code flow can ever reach
the "out_invalid_option:" label if 'mandatory' is set to 1, and when
'mandatory' is non-zero, we'll always have 'value' initialized.Help out the compiler by annotating the variable.
Signed-off-by: Ingo Molnar
Signed-off-by: David S. Miller
24 Nov, 2008
5 commits
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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
Acked-by: Ian McDonald
Signed-off-by: David S. Miller -
Support for Mandatory options is provided by this patch, which will
be used by subsequent feature-negotiation patches.Signed-off-by: Gerrit Renker
Acked-by: Ian McDonald
Acked-by: Arnaldo Carvalho de Melo
Signed-off-by: David S. Miller -
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
Acked-by: Ian McDonald
Acked-by: Arnaldo Carvalho de Melo
Signed-off-by: David S. Miller -
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
Acked-by: Ian McDonald
Signed-off-by: David S. Miller -
With this patch, TX/RX CCIDs can now be changed on a per-connection
basis, which overrides the defaults set by the global sysctl variables
for TX/RX CCIDs.To make full use of this facility, the remaining patches of this patch
set are needed, which track dependencies and activate negotiated
feature values.Signed-off-by: Gerrit Renker
Signed-off-by: David S. Miller
20 Nov, 2008
3 commits
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From: Gerrit Renker
Signed-off-by: David S. Miller
-
This patch prepares RCU migration of listening_hash table for
TCP/DCCP protocols.listening_hash table being small (32 slots per protocol), we add
a spinlock for each slot, instead of a single rwlock for whole table.This should reduce hold time of readers, and writers concurrency.
Signed-off-by: Eric Dumazet
Signed-off-by: David S. Miller -
Signed-off-by: Eric Dumazet
Signed-off-by: David S. Miller
17 Nov, 2008
2 commits
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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
Acked-by: Ian McDonald
Acked-by: Arnaldo Carvalho de Melo
Reviewed-by: Eugene Teo
Signed-off-by: David S. Miller -
This patch deprecates the Ack Ratio sysctl, since
* Ack Ratio is entirely ignored by CCID-3 and CCID-4,
* Ack Ratio currently doesn't work in CCID-2 (i.e. is always set to 1);
* even if it would work in CCID-2, there is no point for a user to change it:
- Ack Ratio is constrained by cwnd (RFC 4341, 6.1.2),
- if Ack Ratio > cwnd, the system resorts to spurious RTO timeouts
(since waiting for Acks which will never arrive in this window),
- cwnd is not a user-configurable value.The only reasonable place for Ack Ratio is to print it for debugging. It is
planned to do this later on, as part of e.g. dccp_probe.With this patch Ack Ratio is now under full control of feature negotiation:
* Ack Ratio is resolved as a dependency of the selected CCID;
* if the chosen CCID supports it (i.e. CCID == CCID-2), Ack Ratio is set to
the default of 2, following RFC 4340, 11.3 - "New connections start with Ack
Ratio 2 for both endpoints";
* what happens then is part of another patch set, since it concerns the
dynamic update of Ack Ratio while the connection is in full flight.Thanks to Tomasz Grobelny for discussion leading up to this patch.
Signed-off-by: Gerrit Renker
Acked-by: Arnaldo Carvalho de Melo
Signed-off-by: David S. Miller