This patch simplifies the interface of ccid2_hc_tx_alloc_seq():
* ccid2_hc_tx_alloc_seq() is always called with an argument of
CCID2_SEQBUF_LEN;
* other code - ccid2_hc_tx_check_sanity() - even depends on the
assumption that ccid2_hc_tx_alloc_seq() has been called with this
particular size;
* passing the `gfp_t' argument to ccid2_hc_tx_alloc_seq() is
redundant with gfp_any().
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This just sets the parameter to bool, since debugging messages are
either on or off.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This enables applications to query the current value of the Maximum
Packet Size via a socket option, suggested as a SHOULD in (RFC 4340,
p. 102).
This socket option is useful to avoid the annoying bail-out via
`-EMSGSIZE'. In particular, as fragmentation is not currently
supported (and its use is partly discouraged in RFC 4340).
With this option, it is possible to size buffers accordingly, e.g.
int buflen = dccp_get_cur_mps(sockfd);
/* or */
if (msgsize > dccp_get_cur_mps(sockfd))
die("message is too large for this path");
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This performs a minor optimisation: when ccid_hc_tx_send_packet
returns a value greater zero, then the same call previously was done
again at the begin of the while loop in dccp_wait_for_ccid.
This patch exploits the available information and schedule-timeouts
directly instead.
Documentation also added.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Since DCCP requires to close both ends of a connection simultaneously,
permission to write in state DCCP_CLOSING is removed in dccp_sendmsg():
* if the sending end closed, it would encounter a write error anyhow;
* if the other end has closed the connection, it accepts no more data.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
This factors code common to dccp_v{4,6}_ctl_send_reset into a separate function,
and adds support for filling in the Data 1 ... Data 3 fields from RFC 4340, 5.6.
It is useful to have this separate, since the following Reset codes will always
be generated from the control socket rather than via dccp_send_reset:
* Code 3, "No Connection", cf. 8.3.1;
* Code 4, "Packet Error" (identification for Data 1 added);
* Code 5, "Option Error" (identification for Data 1..3 added, will be used later);
* Code 6, "Mandatory Error" (same as Option Error);
* Code 7, "Connection Refused" (what on Earth is the difference to "No Connection"?);
* Code 8, "Bad Service Code";
* Code 9, "Too Busy";
* Code 10, "Bad Init Cookie" (not used).
Code 0 is not recommended by the RFC, the following codes would be used in
dccp_send_reset() instead, since they all relate to an established DCCP connection:
* Code 1, "Closed";
* Code 2, "Aborted";
* Code 11, "Aggression Penalty" (12.3).
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
This replaces normal addition with mod-48 addition so that sequence number
wraparound is respected.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
This implements a SHOULD from RFC 4340, 7.5.4:
"To protect against denial-of-service attacks, DCCP implementations SHOULD
impose a rate limit on DCCP-Syncs sent in response to sequence-invalid packets,
such as not more than eight DCCP-Syncs per second."
The rate-limit is maintained on a per-socket basis. This is a more stringent
policy than enforcing the rate-limit on a per-source-address basis and
protects against attacks with forged source addresses.
Moreover, the mechanism is deliberately kept simple. In contrast to
xrlim_allow(), bursts of Sync packets in reply to sequence-invalid packets
are not supported. This foils such attacks where the receipt of a Sync
triggers further sequence-invalid packets. (I have tested this mechanism against
xrlim_allow algorithm for Syncs, permitting bursts just increases the problems.)
In order to keep flexibility, the timeout parameter can be set via sysctl; and
the whole mechanism can even be disabled (which is however not recommended).
The algorithm in this patch has been improved with regard to wrapping issues
thanks to a suggestion by Arnaldo.
Commiter note: Rate limited the step 6 DCCP_WARN too, as it says we're
sending a sync.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
In this patch, duplicated code is removed for the case when a Reset packet is
sent from a connected socket. This code duplication is between dccp_make_reset
and dccp_transmit_skb, which already contained an (up to now entirely unused)
switch statement to fill in the reset code from the DCCP_SKB_CB.
The only thing that has been removed is the call to dst_clone(dst), since
the queue_xmit functions use sk_dst_cache anyway.
I wasn't sure which purpose inet_sk_rebuild_header served, so I left it in.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
This adds fields to support the informational Data 1..3 fields of the
DCCP-Reset packets (RFC 4340, 5.6), and makes minor cosmetic changes
to documentation.
Code which fills in these fields follows in subsequent patches, it is
primarily used for reporting option-processing and feature-negotiation
errors.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
This adds a FIXME to signal that the function dccp_send_delayed_ack is nowhere
used in the entire DCCP/CCID code.
Using a delayed Ack timer is suggested in 11.3 of RFC 4340, but it has also
rather subtle implications for the Ack-Ratio-accounting.
CCID2 does not use this (maybe it should).
I think leaving the function in is good, in case someone wants to implement
this.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
This moves several instances of testing against NULL into the function which is
used to de-reference the CCID-private data.
Committer note: Made the BUG_ON depend on having CONFIG_IP_DCCP_CCID3_DEBUG, as it
is too much to have this on production code. Also made sure that
the macro is used only after checking if sk_state is not LISTEN,
to make it equivalent to what we had before.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
This fixes the code to correspond to RFC 4340, 7.5.4, which states the
exception that a Sync received in state REQUEST generates a Reset (not
a SyncAck).
To achieve this, only a small change is required. Since
dccp_rcv_request_sent_state_process() already uses the correct Reset Code
number 4 ("Packet Error"), we only need to shift the if-statement a few
lines further down.
(To test this case: replace DCCP_PKT_RESPONSE with DCCP_PKT_SYNC
in dccp_make_response.)
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
The parameter `seq' of dccp_send_sync() is in fact an acknowledgement number
and not a sequence number - thus renamed by this patch into `ackno'.
Secondly, a `critical' warning is added when a Sync/SyncAck could not be sent.
Sanity: I have checked all other functions that are called in dccp_transmit_skb,
there are no clashes with the use of dccpd_ack_seq; no other function is
using this slot at the same time.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This updates sequence number checking with regard to RFC 4340, 7.5.4.
Missing in the code was an exception for sequence-invalid Reset packets,
which get a Sync acknowledging GSR, instead of (as usual) P.seqno.
This can lead to an oscillating ping-pong flood of Reset packets.
In fact, it has been observed on the wire as follows:
1. client establishes connection to server;
2. before server can write to client, client crashes without notifying
the server (NB: now no longer possible due to ABORT function);
3. server sends DCCP-Data packet (has no ackno);
4. client generates Reset "No Connection", seqno=0, increments seqno;
5. server replies with Sync, using ackno = P.seqno;
6. client generates Reset "No Connection" with seqno = ackno + 1;
7. goto (5).
The difference is that now in (5) the server uses GSR. This causes the
Reset sent by the client in (6) to become sequence-valid, so that in (7)
the vicious circle is broken; the Reset is then enqueued and causes the
socket to enter TIMEWAIT state.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch is in part required by the next patch; it
* replaces 6 instances of `DCCP_SKB_CB(skb)->dccpd_seq' with `seqno';
* replaces 7 instances of `DCCP_SKB_CB(skb)->dccpd_ack_seq' with `ackno';
* replaces 1 use of dccp_inc_seqno() by unfolding `ADD48' macro in place.
No changes in algorithm, all changes are text replacement/substitution.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
The third parameter of dccp_sample_rtt now becomes useless and is removed.
Also combined the subtraction of the timestamp echo and the elapsed time.
This is safe, since (a) presence of timestamp echo is tested first and (b)
elapsed time is either present and non-zero or it is not set and equals 0
due to the memset in dccp_parse_options.
To avoid measuring option-processing time, the timestamp for measuring the
initial Request/Response RTT sample is taken directly when the function is
called (the Linux implementation always adds a timestamp on the Request,
so there is no loss in doing this).
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This provides a timesource, conveniently used for DCCP timestamps, which
returns the elapsed time in 10s of microseconds since initialisation.
This makes for a wrap-around time of about 11.9 hours, which should be
sufficient for most applications.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch reduces the number of timestamps taken in the receive path
for each packet.
The ccid3_hc_tx_update_x() routine is called in
* the receive path for each CCID3-controlled packet
* for the nofeedback timer (if no feedback arrives during 4 RTT)
Currently, when there is no loss, each packet gets timestamped twice.
The patch resolves this by recycling the first timestamp taken on packet
reception for RTT sampling.
When the no_feedback_timer() is called, then the timestamp argument is
simply set to NULL - so that ccid3_hc_tx_update_x() takes care of the logic.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch makes /proc/net per network namespace. It modifies the global
variables proc_net and proc_net_stat to be per network namespace.
The proc_net file helpers are modified to take a network namespace argument,
and all of their callers are fixed to pass &init_net for that argument.
This ensures that all of the /proc/net files are only visible and
usable in the initial network namespace until the code behind them
has been updated to be handle multiple network namespaces.
Making /proc/net per namespace is necessary as at least some files
in /proc/net depend upon the set of network devices which is per
network namespace, and even more files in /proc/net have contents
that are relevant to a single network namespace.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This trivial patch removes the unneeded pointer newdp, which is never used.
Signed-off-by: Micah Gruber <micah.gruber@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Hopefully captured all single statement cases under net/. I'm
not too sure if there is some policy about #includes that are
"guaranteed" (ie., in the current tree) to be available through
some other #included header, so I just added linux/kernel.h to
each changed file that didn't #include it previously.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
Now to convert the ackvec code to ktime_t so that we can get rid of
dccp_timestamp and the epoch thing in dccp_sock.
Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
The code was too complicated, if p > 0 in ccid3_hc_tx_no_feedback_timer the
timestamp was being obtained to be passed to ccid3_hc_tx_update_x, where only
if p > 0 the timestamp was needed, so just leave it to ccid3_hc_tx_update_x to
obtain the timestamp if needed.
This will help in the upcoming changesets where we'll convert t_ld to ktime_t.
We'll eventually try to reuse ktime_get_real() calls again.
Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
There's a memory leak in net/dccp/feat.c::dccp_feat_empty_confirm(). If we
hit the 'default:' case of the 'switch' statement, then we return without
freeing 'opt', thus leaking 'struct dccp_opt_pend' bytes.
The leak is fixed easily enough by adding a kfree(opt); before the return
statement.
The patch also changes the layout of the 'switch' to be more in line with
CodingStyle.
Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Make sure that spin_unlock_wait() is properly ordered wrt atomic_inc().
(akpm: can't we convert this code to use rwlocks?)
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Slab destructors were no longer supported after Christoph's
c59def9f22 change. They've been
BUGs for both slab and slub, and slob never supported them
either.
This rips out support for the dtor pointer from kmem_cache_create()
completely and fixes up every single callsite in the kernel (there were
about 224, not including the slab allocator definitions themselves,
or the documentation references).
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
AFAICT now that jprobe.entry is a void *, JPROBE_ENTRY doesn't do anything
useful - so remove it ..
I've left a do-nothing version so that out-of-tree jprobes code will still
compile without modifications.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Cc: Prasanna S Panchamukhi <prasanna@in.ibm.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Based on <draft-ietf-ipv6-deprecate-rh0-00.txt>.
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
ccid3_hc_tx_send_packet currently returns 0 when the time difference between
current time and t_nom is less than 1000 microseconds.
In this case the packet is sent immediately; but, unlike other packets that can
be emitted on first attempt, it will not have its window counter updated and
its options set as required. This is a bug.
Fix: Require the time difference to be at least 1000 microseconds. The
algorithm then converges: time differences > 1000 microseconds trigger the
timer in dccp_write_xmit; after timer expiry this function is tried again; when
the time difference is less than 1000, the packet will have its options added
and window counter updated as required.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
This updates the computation of t_nom and t_last_win_count to use the newer
gettimeofday interface.
Committer note: used ktime_to_timeval to set the 'now' variable to t_ld in
ccid3hctx_no_feedback_timer
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
It had just a slab cache, so, for the sake of simplicity just make
dccp_trfc_lib module init routine create the slab cache, no need for users of
the lib to create a private loss_interval object.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Now ccid3_hc_rx_update_li is ready to be moved to
net/dccp/ccids/lib/loss_interval, it uses the same interface as the other
functions there.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This is a preparatory patch for moving these loss interval functions from
net/dccp/ccids/ccid3.c to net/dccp/ccids/lib/loss_interval.c.
Based on a patch by Ian McDonald.
Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
When compiling with EXTRA_CFLAGS=-W noticed that tstamp is not initialised
correctly in dccp_li_calc_first_li.
Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
When compiling with EXTRA_CFLAGS=-W notice that we have signed/unsigned issue
in dccp.h.
Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Recent gcc versions emit warnings when unsigned variables are
compared < 0 or >= 0.
Signed-off-by: Bill Nottingham <notting@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The current IPSEC rule resolution behavior we have does not work for a
lot of people, even though technically it's an improvement from the
-EAGAIN buisness we had before.
Right now we'll block until the key manager resolves the route. That
works for simple cases, but many folks would rather packets get
silently dropped until the key manager resolves the IPSEC rules.
We can't tell these folks to "set the socket non-blocking" because
they don't have control over the non-block setting of things like the
sockets used to resolve DNS deep inside of the resolver libraries in
libc.
With that in mind I coded up the patch below with some help from
Herbert Xu which provides packet-drop behavior during larval state
resolution, controllable via sysctl and off by default.
This lays the framework to either:
1) Make this default at some point or...
2) Move this logic into xfrm{4,6}_policy.c and implement the
ARP-like resolution queue we've all been dreaming of.
The idea would be to queue packets to the policy, then
once the larval state is resolved by the key manager we
re-resolve the route and push the packets out. The
packets would timeout if the rule didn't get resolved
in a certain amount of time.
Signed-off-by: David S. Miller <davem@davemloft.net>
Use menuconfigs instead of menus, so the whole menu can be disabled at
once instead of going through all options.
Signed-off-by: Jan Engelhardt <jengelh@gmx.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
SPIN_LOCK_UNLOCKED cleanup,use __SPIN_LOCK_UNLOCKED instead
Signed-off-by: Milind Arun Choudhary <milindchoudhary@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This prints the value of the parsed Elapsed Time when received via a
Timestamp Echo option [RFC 4342, 13.3].
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This fixes an error in the calculation of t_ipi when X converges towards
very low sending rates (between 1 and 64 bytes per second).
Although this case may not sound likely, it can be reproduced by connecting,
hitting enter (1 byte sent) and waiting for some time, during which the
nofeedback timer halves the sending rate until finally it reaches the region
1..64 bytes/sec. Computing X is handled correctly (tested separately); but by
dividing X _before_ entering the calculation of t_ipi, X becomes zero as
a result. This in turn triggers a BUG condition caught in scaled_div().
Fixed by replacing with equivalent statement and explicit typecast for good
measure.
Calculation verified and effect of patch tested - reduced never below 1 byte
per 64 seconds afterwards, i.e. not allowing divide-by-zero.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
The patch follows the following recommendation made in an erratum to RFC 4342:
"Senders MAY additionally make use of other available RTT measurements,
including those from the initial Request-Response packet exchange."
It implements larger initial windows with regard to this inital RTT measurement,
using the mechanism suggested in draft-ietf-dccp-rfc3448bis, section 4.2.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This replaces the existing occurrences of RTT sampling with
the use of the new function dccp_sample_rtt.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
A recurring problem, in particular in the CCID code, is that RTT samples
from packets with timestamp echo and elapsed time options need to be taken.
This service is provided via a new function dccp_sample_rtt in this patch.
Furthermore, to protect against `insane' RTT samples, the sampled value
is bounded between 100 microseconds and 4 seconds - for which u32 is sufficient.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The CCID 3 and TFRC specs (RFC 4342, RFC 3448, draft-3448bis) make frequent
reference to the computation of the RFC-3390 initial sending rate:
1. Initial sending rate when RTT is known (RFC 4342, p. 6)
2. Response to Idle/Application-Limited periods (RFC 4342, 5.1)
This warrants putting the code into its own function, for later code reuse.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This clears the following sparc64 build warnings:
1) warning: format "%ld" expects type "long int", but argument 3 has type "suseconds_t"
2) warning: format "%llu" expects type "long long unsigned int", but argument 3 has type "__u64"
Fixed by using typecast to unsigned. This is argued to be safe, since the quantities, after
de-scaling (factor 2^6) fit all in u32.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This adds a few more fields of interest to /proc/net/dccpprobe, the following output ensues:
1 2 3 4 5 6 7 8 9 10 11
sec.usec src:sport dst:dport size s rtt p X_calc X_recv X t_ipi
Also made the formatting consistent.
Scripts that go with this can be downloaded from http://139.133.210.30/users/gerrit/dccp/dccp_probe/
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This adds more detail in the wait_for_ccid packet scheduling loop.
In particular, it informs about (i) when delay is used and (ii) why
a packet is discarded.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently debugging output (when configured) is automatically enabled when
DCCP modules are compiled into the kernel rather than built as loadable modules.
This is not necessary, since the module parameters in this case become kernel
commandline parameters, e.g. DCCP or CCID3 debug output can be enabled for a
static build by appending the following at the boot prompt:
dccp.dccp_debug=1 dccp_ccid3.ccid3_debug=1
This patch therefore does away with the more complicated way of always enabling
debug output for static builds
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This:
1. removes a race condition in the access to the scheduled send time t_nom which
results from allowing asynchronous r/w access to t_nom without locks;
2. updates the inter-packet interval t_ipi = s/X when `s' changes, following a
suggestion by Ian McDonald.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This adds a few debugging statements to ccid3.c
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This fixes a bug which uses an invalid comparison.
The bug resulted in the use of invalid loss intervals.
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Acked-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This improves the slow-start phase by using the MSS
(as suggested in RFC 4342, sec. 5) instead of the packet size s.
Also figured out that __u32 is ample resource enough.
After applying, I got the following in the logs:
ccid3_hc_tx_packet_recv: client(f7421700), s=6, MSS=1424, w_init=4380, R_sample=176us, X=24886363
Had the previous variant been used, w_init would have been as low as 24.
Committer note: removed unneeded cast to unsigned long long that was
causing a compiler warning on 64bit architectures.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
No code change at all.
This splits ccid3.c into a RX and a TX section, so that the file has an
organisation similar to the other ones (e.g. packet_history.{h,c}).
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Since CCID3 avoids sending 0-byte data packets (cf. ccid3_hc_tx_send_packet),
testing for zero-payload length, as performed by ccid3_hc_tx_update_s, is
redundant - hence removed by this patch.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This removes two ambiguities in employing the new definition of before48,
following the analysis on http://www.mail-archive.com/dccp@vger.kernel.org/msg01295.html
(1) Updating GSR when P.seqno >= S.SWL
With the old definition we did not update when P.seqno and S.SWL are 2^47 apart. To
ensure the same behaviour as with the old definition, this is replaced with the
equivalent condition dccp_delta_seqno(S.SWL, P.seqno) >= 0
(2) Sending SYNC when P.seqno >= S.OSR
Here it is debatable whether the new definition causes an ambiguity: the case is
similar to (1); and to have consistency with the case (1), we use the equivalent
condition dccp_delta_seqno(S.OSR, P.seqno) >= 0
Detailed Justification
The follows48 relation identifies whether 48-bit sequence number
x is the direct successor of y. Currently, it does not handle cases
of the following type correctly:
follows48(0x(prefix)10000LL, 0x(prefix)0FFFFLL)
where prefix is an arbitrary hex sequence of up to 7 digits.
This is fixed by reusing the new dccp_delta_seqno function.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch
* organizes the sequence arithmetic functions into one corner of dccp.h
* performs a small modification of dccp_set_seqno to make it more widely reusable
(now it is safe to use any number, since it performs modulo-2^48 assignment)
* adds functions and generic macros for 48-bit sequence arithmetic:
--48 bit complement
--modulo-48 addition and modulo-48 subtraction
--dccp_inc_seqno now a special case of add48
Constants renamed following a suggestion by Arnaldo.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Now the skb->nh union has just one member, .raw, i.e. it is just like the
skb->mac union, strange, no? I'm just leaving it like that till the transport
layer is done with, when we'll rename skb->mac.raw to skb->mac_header (or
->mac_header_offset?), ditto for ->{h,nh}.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
For the places where we need a pointer to the network header, it is still legal
to touch skb->nh.raw directly if just adding to, subtracting from or setting it
to another layer header.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch removes the following not or no longer used exports:
- drivers/char/random.c: secure_tcp_sequence_number
- net/dccp/options.c: sysctl_dccp_feat_sequence_window
- net/netlink/af_netlink.c: netlink_set_err
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
We were only checking if there was enough space to put the int, but
left len as specified by the (malicious) user, sigh, fix it by setting
len to sizeof(val) and transfering just one int worth of data, the one
asked for.
Also check for negative len values.
Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
The TX CCID needs the write_xmit_timer for delaying packet sends. Previously
this timer was only activated on active (connecting) sockets.
This patch initialises the write_xmit_timer in sync with the other timers, i.e.
the timer will be ready on any socket. This is used by applications with a
listening socket which start to stream after receiving an initiation by the
client. The write_xmit_timer is stopped when the application closes, as before.
Was tested to work and to remove the timer bug reported on dccp@vger.
Also moved timer initialisation into timer.c (static).
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: David S. Miller <davem@davemloft.net>
This reverts an earlier patch which disabled bidirectional mode, meaning that
a listening (passive) socket was not allowed to write to the other (active)
end of the connection.
This mode had been disabled when there were problems with CCID3, but it
imposes a constraint on socket programming and thus hinders deployment.
A change is included to ignore RX feedback received by the TX CCID3 module.
Many thanks to Andre Noll for pointing out this issue.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
This mirrors a recent change in tcp_open_req_child, whereby the icsk_rto of the
newly created child socket was not set (but rather on the parent socket). Same
fix for DCCP.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This fixes a bug caused by a previous patch, which causes DCCP servers in
LISTEN state to not receive packets.
This patch changes the logic so that
* servers in either LISTEN or OPEN state get the RX half connection packets
* clients in OPEN state get the TX half connection packets
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The semantic effect of insert_at_head is that it would allow new registered
sysctl entries to override existing sysctl entries of the same name. Which is
pain for caching and the proc interface never implemented.
I have done an audit and discovered that none of the current users of
register_sysctl care as (excpet for directories) they do not register
duplicate sysctl entries.
So this patch simply removes the support for overriding existing entries in
the sys_sysctl interface since no one uses it or cares and it makes future
enhancments harder.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: David Howells <dhowells@redhat.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Corey Minyard <minyard@acm.org>
Cc: Neil Brown <neilb@suse.de>
Cc: "John W. Linville" <linville@tuxdriver.com>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Jan Kara <jack@ucw.cz>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Mark Fasheh <mark.fasheh@oracle.com>
Cc: David Chinner <dgc@sgi.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Patrick McHardy <kaber@trash.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Arnaldo Carvalho de Melo <acme@conectiva.com.br>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Many struct file_operations in the kernel can be "const". Marking them const
moves these to the .rodata section, which avoids false sharing with potential
dirty data. In addition it'll catch accidental writes at compile time to
these shared resources.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ehash table layout is currently this one :
First half of this table is used by sockets not in TIME_WAIT state
Second half of it is used by sockets in TIME_WAIT state.
This is non optimal because of for a given hash or socket, the two chain heads
are located in separate cache lines.
Moreover the locks of the second half are never used.
If instead of this halving, we use two list heads in inet_ehash_bucket instead
of only one, we probably can avoid one cache miss, and reduce ram usage,
particularly if sizeof(rwlock_t) is big (various CONFIG_DEBUG_SPINLOCK,
CONFIG_DEBUG_LOCK_ALLOC settings). So we still halves the table but we keep
together related chains to speedup lookups and socket state change.
In this patch I did not try to align struct inet_ehash_bucket, but a future
patch could try to make this structure have a convenient size (a power of two
or a multiple of L1_CACHE_SIZE).
I guess rwlock will just vanish as soon as RCU is plugged into ehash :) , so
maybe we dont need to scratch our heads to align the bucket...
Note : In case struct inet_ehash_bucket is not a power of two, we could
probably change alloc_large_system_hash() (in case it use __get_free_pages())
to free the unused space. It currently allocates a big zone, but the last
quarter of it could be freed. Again, this should be a temporary 'problem'.
Patch tested on ipv4 tcp only, but should be OK for IPV6 and DCCP.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/dccp/ccids/ccid3.c: In function `ccid3_hc_rx_packet_recv':
net/dccp/ccids/ccid3.c:1007: warning: long int format, different type arg (arg 3)
net/dccp/ccids/ccid3.c:1007: warning: long int format, different type arg (arg 4)
opaque types must be suitably cast for printing.
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Do this even for non-blocking sockets. This avoids the silly -EAGAIN
that applications can see now, even for non-blocking sockets in some
cases (f.e. connect()).
With help from Venkat Tekkirala.
Signed-off-by: David S. Miller <davem@davemloft.net>
Revert 931731123a
We can't elide the skb_set_owner_w() here because things like certain
netfilter targets (such as owner MATCH) need a socket to be set on the
SKB for correct operation.
Thanks to Jan Engelhardt and other netfilter list members for
pointing this out.
Signed-off-by: David S. Miller <davem@davemloft.net>
In a recent patch we introduced invalid return codes which will result in the
opposite of what is intended (i.e. send more packets in face of peculiar
network conditions).
This fixes it by returning ~0 which means not calculated as per
dccp_li_hist_calc_i_mean.
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
That accumulated over the last months hackaton, shame on me for not
using git-apply whitespace helping hand, will do that from now on.
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Spotted by David Miller when compiling on sparc64, I reproduced it here on
parisc64, that are the only platforms to define __kernel_suseconds_t as an
'int', all the others, x86_64 and x86 included typedef it as a 'long', but from
the definition of suseconds_t it should just be an 'int' on platforms where it
is >= 32bits, it would not require all the castings from suseconds_t to (int)
when printking variables of this type, that are not needed on parisc64 and
sparc64.
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
This fixes conversion errors which arose by not properly type-casting
from u32 to __u64. Fixed by explicitly casting each type which is not
__u64, or by performing operation after assignment.
The patch further adds missing debug information to track the current
value of X_recv.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
No code change at all.
This reorders the source file to follow the same order as the corresponding
header file.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
No code change at all.
To make the header file easier to read, the following ordering is established
among the declarations:
* hist_new
* hist_delete
* hist_entry_new
* hist_head
* hist_find_entry
* hist_add_entry
* hist_entry_delete
* hist_purge
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
This patch does not alter any algorithm, just the debug message format:
* s#%s, sk=%p#%s(%p)#g
* when a statename is present, it now uses %s(%p, state=%s)
* when only function entry is debugged, it adds an `- entry'
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
This migrates all packet history operations into the routine
ccid3_hc_tx_packet_sent, thereby removing synchronization problems
that occur when, as before, the operations are spread over multiple
routines.
The following minor simplifications are also applied:
* several simplifications now follow from this change - several tests
are now no longer required
* removal of one unnecessary variable (dp)
Justification:
Currently packet history operations span two different routines,
one of which is likely to pass through several iterations of sleeping
and awakening.
The first routine, ccid3_hc_tx_send_packet, allocates an entry and
sets a few fields. The remaining fields are filled in when the second
routine (which is not within a sleeping context), ccid3_hc_tx_packet_sent,
is called. This has several strong drawbacks:
* it is not necessary to split history operations - all fields can be
filled in by the second routine
* the first routine is called multiple times, until a packet can be sent,
and sleeps meanwhile - this causes a lot of difficulties with regard to
keeping the list consistent
* since both routines do not have a producer-consumer like synchronization,
it is very difficult to maintain data across calls to these routines
* the fact that the routines are called in different contexts (sleeping, not
sleeping) adds further problems
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
This removes the `dccphtx_ccval' field since it is nowhere used in the code and
in fact not necessary for the accounting.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
This puts the window counter computation [RFC 4342, 8.1] into a separate
function which is called whenever a new packet is ready for immediate
transmission in ccid3_hc_tx_send_packet.
Justification:
The window counter update was previously computed after the packet was sent. This has
two drawbacks, both fixed by this patch:
1) re-compute another timestamp almost directly after the packet was sent (expensive),
2) the CCVal for the window counter is needed at the instant the packet is sent.
Further details:
The initialisation of the window counter is left in the state NO_SENT, as before.
The algorithm will do nothing if either RTT is initialised to 0 (which is ok) or if
the RTT value remains below 4 microseconds (which is almost pathological).
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
CCID3 performance depends much on the accuracy of RTT samples. If RTT
samples grow too large, performance can be catastrophically poor.
To limit the amount of possible damage in such cases, the patch
* introduces an upper limit which identifies a maximum `sane' RTT value;
* uses a macro to enforce this upper limit.
Using a macro was given preference, since it is necessary to identify the
calling function in the warning message. Since exceeding this threshold
identifies a critical condition, DCCP_CRIT is used and not DCCP_WARN.
Many thanks to Ian McDonald for collaboration on this issue.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
In both the sender and the receiver it is possible that the stored
RTT value is accessed before an actual RTT estimate has been computed.
This patch
* initialises the sender RTT to 0
- the sender always accesses the RTT in ccid3_hc_tx_packet_sent
- the RTT is further needed for the window counter algorithm
* replaces the receiver initialisation of 5msec with 0
- which has the same effect and removes an `XXX'
- the RTT value is needed in ccid3_hc_rx_packet_recv as rtt_prev
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
The function ccid3_hc_tx_insert_options only does a redundant no-op,
as the operation
DCCP_SKB_CB(skb)->dccpd_ccval = hctx->ccid3hctx_last_win_count;
is already performed _unconditionally_ in ccid3_hc_tx_send_packet.
Since there is further no current need for this function, it is removed
entirely. Since furthermore, there is actually no present need for the
entire interface function ccid_hc_tx_insert_options, it was decided to
remove it also, to clean up the interface.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
This adds a (debug) warning message which is triggered whenever a packet is
discarded due to send failure.
It also adds a conditional, so that an interruption during dccp_wait_for_ccid
is not treated as a `BUG': the rationale is that interruptions are external,
whereas bug warnings are concerned with the internals.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
This is an optimisation to reduce CPU load. The received feedback is now
only directed to the active CCID component, without requiring processing
also by the inactive one.
As a consequence, a similar test in ccid3.c is now redundant and is
also removed.
Justification:
Currently DCCP works as a unidirectional service, i.e. a listening server
is not at the same time a connecting client.
As far as I can see, several modifications are necessary until that
becomes possible.
At the present time, received feedback is both fed to the rx/tx CCID
modules. In unidirectional service, only one of these is active at any
one time.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
In migrating towards using the newer functions scaled_div/scaled_div32
for TFRC computations mapped from floating-point onto integer arithmetic,
this completes the last stage of modifications.
In particular, the overflow case for computing X_calc is circumvented by
* breaking the computation into two stages
* the first stage, res = (s*1E6)/R, cannot overflow due to use of u64
* in the second stage, res = (res*1E6)/f, overflow on u32 is avoided due
to (i) returning UINT_MAX in this case (which is logically appropriate)
and (ii) issuing a warning message into the system log (since very likely
there is a problem somewhere else with the parameters)
Lastly, all such scaling operations are now exported into tfrc.h, since
actually this form of scaled computation is specific to TFRC and not to CCID3.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Problem:
Most target types in the CCID3 code are u32, so subtle conversion errors
can occur if signed time calculations yield negative results: the original
values are lost in the conversion to unsigned, calculation errors go undetected.
This patch therefore
* sets all critical time types from unsigned to suseconds_t
* avoids comparison between signed/unsigned via type-casting
* provides ample warning messages in case time calculations are negative
These warning messages can be removed at a later stage when the code
has undergone more testing.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
This simplifies the calculation of a value p for a given fval when the
first loss interval is computed (RFC 3448, 6.3.1). It makes use of the
two new functions scaled_div/scaled_div32 to provide overflow protection.
Additionally, protection against divide-by-zero is extended - in this
case the function will return the maximally possible value of p=100%.
Background:
The maximum fval, f(100%), is approximately 244, i.e. the scaled value of fval
should never exceed 244E6, which fits easily into u32. The problem is the scaling
by 10^6, since additionally R(TT) is in microseconds.
This is resolved by breaking the division into two stages: the first stage
computes fval=(s*10^6)/R, stores that into u64; the second stage computes
fval = (fval*10^6)/X_recv and complains if overflow is reached for u32.
This case is safe since the TFRC reverse-lookup routine then returns p=100%.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
This replaces the remaining uses of usecs_div with scaled_div32, which
internally uses 64bit division and produces a warning on overflow.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
This patch
* resolves a bug where packets smaller than 32/64 bytes resulted in sending rates of 0
* supports all sending rates from 1/64 bytes/second up to 4Gbyte/second
* simplifies the present overflow problems in calculations
Current sending rate X and the cached value X_recv of the receiver-estimated
sending rate are both scaled by 64 (2^6) in order to
* cope with low sending rates (minimally 1 byte/second)
* allow upgrading to use a packets-per-second implementation of CCID 3
* avoid calculation errors due to integer arithmetic cut-off
The patch implements a revised strategy from
http://www.mail-archive.com/dccp@vger.kernel.org/msg01040.html
The only difference with regard to that strategy is that t_ipi is already
used in the calculation of the nofeedback timeout, which saves one division.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
This fixes
1) a bug in the recomputation of the sending rate by the nofeedback
timer when no feedback at all has so far been sent by the receiver:
min_t was used instead of max_t, which is wrong (cf. RFC 3448, p. 10);
2) an error in the computation of larger initial windows: instead of
min(... max()) (cf. RFC 4342, 5.), the code had used max(... max()).
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
This performs two optimisations for the recomputation of the sending rate.
1) Currently the target sending rate X_calc is recalculated whenever
a) the nofeedback timer expires, or
b) a feedback packet is received.
In the (a) case, recomputing X_calc is redundant, since
* the parameters p and RTT do not change in between the
reception of feedback packets;
* the parameter X_recv is either modified from received
feedback or via the nofeedback timer;
* a test (`p == 0') in the nofeedback timer avoids using
a stale/undefined value of X_calc if p was previously 0.
2) The nofeedback timer now only recomputes a timestamp when p == 0.
This is according to step (4) of [RFC 3448, 4.3] and avoids
unnecessarily determining a timestamp.
A debug statement about not updating X is also removed - it helps very
little in debugging and just clutters the logs.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
This patch follows a suggestion by Ian McDonald and ensures that in
the current code the value of p can not exceed 100%. Such a value is
illegal and would consequently cause a bug condition in tfrc_calc_x().
The receiver case is also tested, and a warning message is added.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
It simplifies waiting for the CCID module to signal that a packet
is ready to be sent. Other simplifications flow on from this such as
removing constants.
As a result of this EAGAIN is not returned any more by dccp_wait_for_ccid
(which would otherwise lead to unnecessarily discarding the packet in
dccp_write_xmit).
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Replace all uses of kmem_cache_t with struct kmem_cache.
The patch was generated using the following script:
#!/bin/sh
#
# Replace one string by another in all the kernel sources.
#
set -e
for file in `find * -name "*.c" -o -name "*.h"|xargs grep -l $1`; do
quilt add $file
sed -e "1,\$s/$1/$2/g" $file >/tmp/$$
mv /tmp/$$ $file
quilt refresh
done
The script was run like this
sh replace kmem_cache_t "struct kmem_cache"
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
SLAB_ATOMIC is an alias of GFP_ATOMIC
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Conflicts:
drivers/ata/libata-scsi.c
include/linux/libata.h
Futher merge of Linus's head and compilation fixups.
Signed-Off-By: David Howells <dhowells@redhat.com>
Conflicts:
drivers/infiniband/core/iwcm.c
drivers/net/chelsio/cxgb2.c
drivers/net/wireless/bcm43xx/bcm43xx_main.c
drivers/net/wireless/prism54/islpci_eth.c
drivers/usb/core/hub.h
drivers/usb/input/hid-core.c
net/core/netpoll.c
Fix up merge failures with Linus's head and fix new compilation failures.
Signed-Off-By: David Howells <dhowells@redhat.com>
This replaces the linear search algorithm for reverse lookup with
binary search.
It has the advantage of better scalability: O(log2(N)) instead of O(N).
This means that the average number of iterations is reduced from 250
(linear search if each value appears equally likely) down to at most 9.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
This patch deprecates the existing use of an arbitrary value TFRC_SMALLEST_P
for low-threshold values of p. This avoids masking low-resolution errors.
Instead, the code now checks against real boundaries (implemented by preceding
patch) and provides warnings whenever a real value falls below the threshold.
If such messages are observed, it is a better solution to take this as an
indication that the lookup table needs to be re-engineered.
Changelog:
----------
This patch
* makes handling all TFRC resolution errors local to the TFRC library
* removes unnecessary test whether X_calc is 'infinity' due to p==0 -- this
condition is already caught by tfrc_calc_x()
* removes setting ccid3hctx_p = TFRC_SMALLEST_P in ccid3_hc_tx_packet_recv
since this is now done by the TFRC library
* updates BUG_ON test in ccid3_hc_tx_no_feedback_timer to take into account
that p now is either 0 (and then X_calc is irrelevant), or it is > 0; since
the handling of TFRC_SMALLEST_P is now taken care of in the tfrc library
Justification:
--------------
The TFRC code uses a lookup table which has a bounded resolution.
The lowest possible value of the loss event rate `p' which can be
resolved is currently 0.0001. Substituting this lower threshold for
p when p is less than 0.0001 results in a huge, exponentially-growing
error. The error can be computed by the following formula:
(f(0.0001) - f(p))/f(p) * 100 for p < 0.0001
Currently the solution is to use an (arbitrary) value
TFRC_SMALLEST_P = 40 * 1E-6 = 0.00004
and to consider all values below this value as `virtually zero'. Due to
the exponentially growing resolution error, this is not a good idea, since
it hides the fact that the table can not resolve practically occurring cases.
Already at p == TFRC_SMALLEST_P, the error is as high as 58.19%!
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
This
* adds documentation about the lowest resolution that is possible within
the bounds of the current lookup table
* defines a constant TFRC_SMALLEST_P which defines this resolution
* issues a warning if a given value of p is below resolution
* combines two previously adjacent if-blocks of nearly identical
structure into one
This patch does not change the algorithm as such.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
1) For the forward X_calc lookup, it
* protects effectively against RTT=0 (this case is possible), by
returning the maximal lookup value instead of just setting it to 1
* reformulates the array-bounds exceeded condition: this only happens
if p is greater than 1E6 (due to the scaling)
* the case of negative indices can now with certainty be excluded,
since documentation shows that the formulas are within bounds
* additional protection against p = 0 (would give divide-by-zero)
2) For the reverse lookup, it warns against
* protects against exceeding array bounds
* now returns 0 if f(p) = 0, due to function definition
* warns about minimal resolution error and returns the smallest table
value instead of p=0 [this would mask congestion conditions]
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
This fixes the following small error in tfrc_calc_x_reverse_lookup.
1) The table is generated by the following equations:
lookup[index][0] = g((index+1) * 1000000/TFRC_CALC_X_ARRSIZE);
lookup[index][1] = g((index+1) * TFRC_CALC_X_SPLIT/TFRC_CALC_X_ARRSIZE);
where g(q) is 1E6 * f(q/1E6)
2) The reverse lookup assigns an entry in lookup[index][small]
3) This index needs to match the above, i.e.
* if small=0 then
p = (index + 1) * 1000000/TFRC_CALC_X_ARRSIZE
* if small=1 then
p = (index+1) * TFRC_CALC_X_SPLIT/TFRC_CALC_X_ARRSIZE
These are exactly the changes that the patch makes; previously the code did
not conform to the way the lookup table was generated (this difference resulted
in a mean error of about 1.12%).
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
This adds documentation for the TCP Reno throughput equation which is at
the heart of the TFRC sending rate / loss rate calculations.
It spells out precisely how the values were determined and what they mean.
The equations were derived through reverse engineering and found to be
fully accurate (verified using test programs).
This patch does not change any code.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
This avoids a (harmless) warning message being printed at the DCCP server
(the receiver of a DCCP half connection).
Incoming packets are both directed to
* ccid_hc_rx_packet_recv() for the server half
* ccid_hc_tx_packet_recv() for the client half
The message gets printed since on a server the client half is currently not
sending data packets.
This is resolved for the moment by checking the DCCP-role first. In future
times (bidirectional DCCP connections), this test may have to be more
sophisticated.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
The main object of this patch is the following bug:
==> In ccid3_hc_tx_packet_recv, the parameters p and X_recv were updated
_after_ the send rate was calculated. This is clearly an error and is
resolved by re-ordering statements.
In addition,
* r_sample is converted from u32 to long to check whether the time difference
was negative (it would otherwise be converted to a large u32 value)
* protection against RTT=0 (this is possible) is provided in a further patch
* t_elapsed is also converted to long, to match the type of r_sample
* adds a a more debugging information regarding current send rates
* various trivial comment/documentation updates
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
This bug resulted in ccid3_hc_tx_send_packet returning negative
delay values, which in turn triggered silently dequeueing packets in
dccp_write_xmit. As a result, only a few out of the submitted packets made
it at all onto the network. Occasionally, when dccp_wait_for_ccid was
involved, this also triggered a bug warning since ccid3_hc_tx_send_packet
returned a negative value (which in reality was a negative delay value).
The cause for this bug lies in the comparison
if (delay >= hctx->ccid3hctx_delta)
return delay / 1000L;
The type of `delay' is `long', that of ccid3hctx_delta is `u32'. When comparing
negative long values against u32 values, the test returned `true' whenever delay
was smaller than 0 (meaning the packet was overdue to send).
The fix is by casting, subtracting, and then testing the difference with
regard to 0.
This has been tested and shown to work.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
The TFRC nofeedback timer normally expires after the maximum of 4
RTTs and twice the current send interval (RFC 3448, 4.3). On LANs
with a small RTT this can mean a high processing load and reduced
performance, since then the nofeedback timer is triggered very
frequently.
This patch provides a configuration option to set the bound for the
nofeedback timer, using as default 100 milliseconds.
By setting the configuration option to 0, strict RFC 3448 behaviour
can be enforced for the nofeedback timer.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
This patch implements a suggestion by Ian McDonald and
1) Avoids tests against negative packet lengths by using unsigned int
for packet payload lengths in the CCID send_packet()/packet_sent() routines
2) As a consequence, it removes an now unnecessary test with regard to `len > 0'
in ccid3_hc_tx_packet_sent: that condition is always true, since
* negative packet lengths are avoided
* ccid3_hc_tx_send_packet flags an error whenever the payload length is 0.
As a consequence, ccid3_hc_tx_packet_sent is never called as all errors
returned by ccid_hc_tx_send_packet are caught in dccp_write_xmit
3) Removes the third argument of ccid_hc_tx_send_packet (the `len' parameter),
since it is currently always set to skb->len. The code is updated with regard
to this parameter change.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
This implements the larger-initial-windows feature for CCID 3, as described in
section 5 of RFC 4342. When the first feedback packet arrives, the sender can
send up to 2..4 packets per RTT, instead of just one.
The patch further
* reduces the number of timestamping calls by passing the timestamp value
(which is computed in one of the calling functions anyway) as argument
* renames one constant with a very long name into one which is shorter and
resembles the one in RFC 3448 (t_mbi)
* simplifies some of the min_t/max_t cases where both `x', `y' have the same
type
Commiter note: renamed TFRC_t_mbi to TFRC_T_MBI, to follow Linux coding style.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
To reflect the fact that this now is of no effect, not making apps
stop working, just be warned in the system log.
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
This removes and cleans up unused variables and structures which have become
unnecessary following the introduction of the EWMA patch to automatically track
the CCID 3 receiver/sender packet sizes `s'.
It deprecates the PACKET_SIZE socket option by returning an error code and
printing a deprecation warning if an application tries to read or write this
socket option.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
This corrects the setting of the nofeedback timer with regard to RFC
3448 - previously it was not set to max(4*R, 2*s/X) as specified. Using
the maximum of 1 second as upper bound (as it was done before) can have
detrimental effects, especially if R is small.
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
This is in response to a request sent earlier by Eric W. Biederman
and replaces all sysctl numbers for net.dccp.default with CTL_UNNUMBERED.
It has been tested to compile and to work.
Commiter note: I've removed the use of CTL_UNNUMBERED, not setting .ctl_name
sets it to 0, that is the what CTL_UNNUMBERED is, reason is
to avoid unneeded source code cluttering.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Gerrit Renker
Arnaldo Carvalho de Melo
Eric W. Biederman
Micah Gruber
Ilpo Järvinen
Jesper Juhl
Oleg Nesterov
Paul Mundt
Linus Torvalds
Michael Ellerman
YOSHIFUJI Hideaki
Adrian Bunk
Arnaldo Carvalho de Melo
Ian McDonald
Bill Nottingham
David S. Miller
Jan Engelhardt
Milind Arun Choudhary
Patrick McHardy
Arjan van de Ven
Eric Dumazet
Andrew Morton
Arnaldo Carvalho de Melo
Christoph Lameter
David Howells