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* dccp: Fix sparse warningsGerrit Renker2008-06-113-12/+11
| | | | | | | | | | | | | | | | | | | | | | | This patch fixes the following sparse warnings: * nested min(max()) expression: net/dccp/ccids/ccid3.c:91:21: warning: symbol '__x' shadows an earlier one net/dccp/ccids/ccid3.c:91:21: warning: symbol '__y' shadows an earlier one * Declaration of function prototypes in .c instead of .h file, resulting in "should it be static?" warnings. * Declared "struct dccpw" static (local to dccp_probe). * Disabled dccp_delayed_ack() - not fully removed due to RFC 4340, 11.3 ("Receivers SHOULD implement delayed acknowledgement timers ..."). * Used a different local variable name to avoid net/dccp/ackvec.c:293:13: warning: symbol 'state' shadows an earlier one net/dccp/ackvec.c:238:33: originally declared here * Removed unused functions `dccp_ackvector_print' and `dccp_ackvec_print'. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
* dccp ccid-3: Bug-Fix - Zero RTT is possibleGerrit Renker2008-06-111-2/+8
| | | | | | | | | | | | | | | | | | | | | In commit $(825de27d9e40b3117b29a79d412b7a4b78c5d815) (from 27th May, commit message `dccp ccid-3: Fix "t_ipi explosion" bug'), the CCID-3 window counter computation was fixed to cope with RTTs < 4 microseconds. Such RTTs can be found e.g. when running CCID-3 over loopback. The fix removed a check against RTT < 4, but introduced a divide-by-zero bug. All steady-state RTTs in DCCP are filtered using dccp_sample_rtt(), which ensures non-zero samples. However, a zero RTT is possible on initialisation, when there is no RTT sample from the Request/Response exchange. The fix is to use the fallback-RTT from RFC 4340, 3.4. This is also better than just fixing update_win_count() since it allows other parts of the code to always assume that the RTT is non-zero during the time that the CCID is used. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
* dccp ccid-3: Fix "t_ipi explosion" bugGerrit Renker2008-05-271-9/+4
| | | | | | | | | | | | | | | | | | | | | | The identification of this bug is thanks to Cheng Wei and Tomasz Grobelny. To avoid divide-by-zero, the implementation previously ignored RTTs smaller than 4 microseconds when performing integer division RTT/4. When the RTT reached a value less than 4 microseconds (as observed on loopback), this prevented the Window Counter CCVal value from advancing. As a result, the receiver stopped sending feedback. This in turn caused non-ending expiries of the nofeedback timer at the sender, so that the sending rate was progressively reduced until reaching the minimum of one packet per 64 seconds. The patch fixes this bug by handling integer division more intelligently. Due to consistent use of dccp_sample_rtt(), divide-by-zero-RTT is avoided. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Signed-off-by: David S. Miller <davem@davemloft.net>
* dccp: ccid2.c, ccid3.c use clamp(), clamp_t()Harvey Harrison2008-05-022-3/+3
| | | | | | | | Makes the intention of the nested min/max clear. Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* [CCID3]: Kill some bloatIlpo Järvinen2008-01-281-1/+1
| | | | | | | | | | | | | | | | | | | | | | Without a number of CONFIG.*DEBUG: net/dccp/ccids/ccid3.c: ccid3_hc_tx_update_x | -170 ccid3_hc_tx_packet_sent | -175 ccid3_hc_tx_packet_recv | -169 ccid3_hc_tx_no_feedback_timer | -192 ccid3_hc_tx_send_packet | -144 5 functions changed, 850 bytes removed, diff: -850 net/dccp/ccids/ccid3.c: ccid3_update_send_interval | +191 1 function changed, 191 bytes added, diff: +191 net/dccp/ccids/ccid3.o: 6 functions changed, 191 bytes added, 850 bytes removed, diff: -659 Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* [CCID3]: Nofeedback timer according to rfc3448bisGerrit Renker2008-01-281-34/+29
| | | | | | | | | | | | | | | | This implements the changes to the nofeedback timer handling suggested in draft rfc3448bis00, section 4.4. In particular, these changes mean: * better handling of the lossless case (p == 0) * the timestamp for computing t_ld becomes obsolete * much more recent document (RFC 3448 is almost 5 years old) * concepts in rfc3448bis arose from a real, working implementation (cf. sec. 12) 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>
* [CCID3]: Implement rfc3448bis changes to feedback receptionGerrit Renker2008-01-281-21/+26
| | | | | | | | | | This implements the algorithm to update the allowed sending rate X upon receiving feedback packets, as described in draft rfc3448bis, 4.2/4.3. 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>
* [CCID3]: Remove two irrelevant states in TX feedback handlingGerrit Renker2008-01-281-89/+84
| | | | | | | | | | | * the NO_SENT state is only triggered in bidirectional mode, costing unnecessary processing. * the TERM (terminating) state is irrelevant. 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>
* [CCID3]: Use a function to update p_inv, and p is never usedGerrit Renker2008-01-282-7/+12
| | | | | | | | | | | | This patch 1) concentrates previously scattered computation of p_inv into one function; 2) removes the `p' element of the CCID3 RX sock (it is redundant); 3) makes the tfrc_rx_info structure standalone, only used on demand. 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>
* [CCID]: More informative registrationGerrit Renker2008-01-282-2/+2
| | | | | | | | | | | | | | | | | | | | | The patch makes the registration messages of CCID 2/3 a bit more informative: instead of repeating the CCID number as currently done, "CCID: Registered CCID 2 (ccid2)" or "CCID: Registered CCID 3 (ccid3)", the descriptive names of the CCID's (from RFCs) are now used: "CCID: Registered CCID 2 (TCP-like)" and "CCID: Registered CCID 3 (TCP-Friendly Rate Control)". To allow spaces in the name, the slab name string has been changed to refer to the numeric CCID identifier, using the same format as 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@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TFRC]: Remove previous loss intervals implementationGerrit Renker2008-01-282-275/+1
| | | | | | | 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>
* [CCID3]: Interface CCID3 code with newer Loss Intervals DatabaseGerrit Renker2008-01-284-31/+79
| | | | | | | | | | | | | | | | This hooks up the TFRC Loss Interval database with CCID 3 packet reception. In addition, it makes the CCID-specific computation of the first loss interval (which requires access to all the guts of CCID3) local to ccid3.c. The patch also fixes an omission in the DCCP code, that of a default / fallback RTT value (defined in section 3.4 of RFC 4340 as 0.2 sec); while at it, the upper bound of 4 seconds for an RTT sample has been reduced to match the initial TCP RTO value of 3 seconds from[RFC 1122, 4.2.3.1]. 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>
* [TFRC]: CCID3 (and CCID4) needs to access these inlinesGerrit Renker2008-01-282-30/+31
| | | | | | | | | | This moves two inlines back to packet_history.h: these are not private to packet_history.c, but are needed by CCID3/4 to detect whether a new loss is indicated, or whether a loss is already pending. 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>
* [CCID3]: Redundant debugging output / documentationGerrit Renker2008-01-282-4/+2
| | | | | | | | | | | | | | | Each time feedback is sent two lines are printed: ccid3_hc_rx_send_feedback: client ... - entry ccid3_hc_rx_send_feedback: Interval ...usec, X_recv=..., 1/p=... The first line is redundant and thus removed. Further, documentation of ccid3_hc_rx_sock (capitalisation) is made consistent. 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>
* [TFRC]: Ringbuffer to track loss interval historyGerrit Renker2008-01-285-14/+435
| | | | | | | | | | | | | | | | | | | | | | | A ringbuffer-based implementation of loss interval history is easier to maintain, allocate, and update. The `swap' routine to keep the RX history sorted is due to and was written by Arnaldo Carvalho de Melo, simplifying an earlier macro-based variant. Details: * access to the Loss Interval Records via macro wrappers (with safety checks); * simplified, on-demand allocation of entries (no extra memory consumption on lossless links); cache allocation is local to the module / exported as service; * provision of RFC-compliant algorithm to re-compute average loss interval; * provision of comprehensive, new loss detection algorithm - support for all cases of loss, including re-ordered/duplicate packets; - waiting for NDUPACK=3 packets to fill the hole; - updating loss records when a late-arriving packet fills a hole. 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>
* [TFRC]: Loss interval code needs the macros/inlines that were movedGerrit Renker2008-01-282-35/+35
| | | | | | | | | | | | This moves the inlines (which were previously declared as macros) back into packet_history.h since the loss detection code needs to be able to read entries from the RX history in order to create the relevant loss entries: it needs at least tfrc_rx_hist_loss_prev() and tfrc_rx_hist_last_rcv(), which in turn require the definition of the other inlines (macros). 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>
* [TFRC]: Put RX/TX initialisation into tfrc.cGerrit Renker2008-01-282-44/+55
| | | | | | | | | | This separates RX/TX initialisation and puts all packet history / loss intervals initialisation into tfrc.c. The organisation is uniform: slab declaration -> {rx,tx}_init() -> {rx,tx}_exit() 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>
* [CCID3]: HC-receiver should not insert timestamps as HC-sender doesn't uses itGerrit Renker2008-01-281-2/+1
| | | | | | 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>
* [TFRC]: The function tfrc_rx_hist_entry_delete() is not used anymoreGerrit Renker2008-01-281-5/+0
| | | | | | 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>
* [TFRC]: Move comment.Gerrit Renker2008-01-281-5/+5
| | | | | | | | | Moved up the comment "Receiver routines" above the first occurrence of RX history routines. 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>
* [TFRC]: New rx history codeArnaldo Carvalho de Melo2008-01-285-355/+327
| | | | | | | | | | | | | | | | | | | | | | | | | | Credit here goes to Gerrit Renker, that provided the initial implementation for this new codebase. I modified it just to try to make it closer to the existing API, renaming some functions, add namespacing and fix one bug where the tfrc_rx_hist_alloc was not freeing the allocated ring entries on the error path. Original changeset comment from Gerrit: ----------- This provides a new, self-contained and generic RX history service for TFRC based protocols. Details: * new data structure, initialisation and cleanup routines; * allocation of dccp_rx_hist entries local to packet_history.c, as a service exported by the dccp_tfrc_lib module. * interface to automatically track highest-received seqno; * receiver-based RTT estimation (needed for instance by RFC 3448, 6.3.1); * a generic function to test for `data packets' as per RFC 4340, sec. 7.7. 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>
* [CCID3]: The receiver of a half-connection does not set window counter valuesGerrit Renker2008-01-281-1/+0
| | | | | | | | | Only the sender sets window counters [RFC 4342, sections 5 and 8.1]. 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>
* [TFRC]: Rename dccp_rx_ to tfrc_rx_Arnaldo Carvalho de Melo2008-01-284-92/+92
| | | | | | | | This is in preparation for merging the new rx history code written by Gerrit Renker. 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>
* [TFRC]: Make the rx history slab be globalArnaldo Carvalho de Melo2008-01-283-113/+60
| | | | | | | | This is in preparation for merging the new rx history code written by Gerrit Renker. 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>
* [TFRC]: Rename tfrc_tx_hist to tfrc_tx_hist_slab, for consistencyArnaldo Carvalho de Melo2008-01-281-10/+10
| | | | | | 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>
* [TFRC]: Provide central source file and debug facilityGerrit Renker2008-01-286-35/+75
| | | | | | | | | | | | | | | | This patch changes the tfrc_lib module in the following manner: (1) a dedicated tfrc source file to call the packet history & loss interval init/exit functions. (2) a dedicated tfrc_pr_debug macro with toggle switch `tfrc_debug'. Commiter note: renamed tfrc_module.c to tfrc.c, and made CONFIG_IP_DCCP_CCID3 select IP_DCCP_TFRC_LIB. 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>
* [TFRC]: Hide tx history details from the CCIDsArnaldo Carvalho de Melo2008-01-283-28/+41
| | | | | | | Based on a previous patch by Gerrit Renker. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TFRC]: Migrate TX history to singly-linked lisArnaldo Carvalho de Melo2008-01-285-187/+102
| | | | | | | | | | | | | | | | | | | | | | | | | | This patch was based on another made by Gerrit Renker, his changelog was: ------------------------------------------------------ The patch set migrates TFRC TX history to a singly-linked list. The details are: * use of a consistent naming scheme (all TFRC functions now begin with `tfrc_'); * allocation and cleanup are taken care of internally; * provision of a lookup function, which is used by the CCID TX infrastructure to determine the time a packet was sent (in turn used for RTT sampling); * integration of the new interface with the present use in CCID3. ------------------------------------------------------ Simplifications I did: . removing the tfrc_tx_hist_head that had a pointer to the list head and another for the slabcache. . No need for creating a slabcache for each CCID that wants to use the TFRC tx history routines, create a single slabcache when the dccp_tfrc_lib module init routine is called. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* [CCID2]: Remove misleading commentGerrit Renker2008-01-281-10/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | This removes a comment which identifies an `issue' with dccp_write_xmit() where there is none. The comment assumes it is possible that a packet is sent between the calls to ccid_hc_tx_send_packet(), dccp_transmit_skb(), ccid_hc_tx_packet_sent() (in the above order) in dccp_write_xmit(). I think that this is impossible, since dccp_write_xmit() is always called under lock: * when called as dccp_write_xmit(sk, 1) from dccp_send_close(), the socket is locked (see code comment above dccp_send_close()); * when called as dccp_write_xmit(sk, 0) from dccp_send_msg(), it is after lock_sock() has been called; * when called as dccp_write_xmit(sk, 0) from dccp_write_xmit_timer(), bh_lock_sock() has been called and the if/else statement has made sure that sk_lock.owner is not set; * there are no other places where dccp_write_xmit() is called. Furthermore, the debug statement for printing the sequence number of the packet just sent has been removed, since the entire list is being printed anyway and so the entry of that number appears last. 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>
* [CCID2]: Remove redundant ack-counting variableGerrit Renker2008-01-282-35/+17
| | | | | | | | | | | | | | | | | The code used two different variables to count Acks, one of them redundant. This patch reduces the number of Ack counters to one. The type of the Ack counter has also been changed to u32 (twice the range of int); and the variable has been renamed into `packets_acked' - for consistency with RFC 3465 (and similarly named variables are used by TCP and SCTP). Lastly, a slightly less aggressive `maxincr' increment is used (for even Ack Ratios, maxincr was Ack Ratio/2 + 1 instead of Ack Ratio/2). 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>
* [CCID2]: Remove redundant synchronisation variableGerrit Renker2008-01-282-10/+2
| | | | | | | | | | | | | | | | | | | | | | | | | This removes the synchronisation variable `ccid2hctx_sendwait', which is set to 1 when the CCID2 sender may send a new packet, and which is set to 0 otherwise The variable is redundant, since it is only used in combination with the hc_tx_send_packet/ hc_tx_packet_sent function pair. Both functions are called under socket lock, so the following happens when the CCID2 may send a new packet: * it sets sendwait = 1 in tx_send_packet and returns 0; * the subsequent call to tx_packet_sent clears the sendwait flag; * since tx_send_packet returns 0 if and only if sendwait == 1, the BUG_ON condition in tx_packet_sent is never satisfied, since that function is never called when tx_send_packet returns a value different from 0 (cf. dccp_write_xmit); * the call to tx_packet_sent clears the flag so that the condition "!sendwait" is true the next time tx_packet_sent is called. In other words, it is sufficient to just return 0 / not-0 to synchronise tx_send_packet and tx_packet_sent -- which is what the patch does. 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>
* [CCID2]: Redundant debugging outputGerrit Renker2008-01-281-6/+0
| | | | | | | | | | | | | | | | This reduces the amount of redundant debugging messages: * pipe/cwnd are printed in both tx_send_packet() and tx_packet_sent(). Both functions are called immediately after one another, so one occurrence is sufficient. * Since tx_packet_sent() prints pipe/cwnd already, the second printk for pipe is redundant. * In tx_packet_sent() the check_sanity function is called twice (at the begin and at the end). 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>
* [CCID2]: Replace pipe assignment-function with assignmentGerrit Renker2008-01-282-11/+8
| | | | | | | | | | | | | | The function ccid2_change_pipe only does an assignment. This patch simplifies the code by replacing the function with the assignment it performs. Furthermore, the type of pipe is promoted from `signed' to unsigned (increasing the range). As a result, a BUG_ON test for negative values now becomes obsolete (for safety not removed, but replaced with a less annoying `DCCP_BUG'). 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>
* [CCID2]: Replace cwnd assignment-function with assignmentGerrit Renker2008-01-282-16/+8
| | | | | | | | | | | | | | | | The current function ccid2_change_cwnd in effect makes only an assignment, as the test whether cwnd has reached 0 is only required when cwnd is halved. This patch simplifies the code by replacing the function with the assignment it performs. Furthermore, since ssthresh derives from cwnd and appears in many assignments and comparisons, the type of ssthresh has also been changed to match that of cwnd. 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>
* [CCID2]: Replace read-only variable with constantGerrit Renker2008-01-282-6/+5
| | | | | | | | | | This replaces the field member `numdupack', which was used as a read-only constant in the code, with a #define. 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>
* [CCID2]: Remove unused variableGerrit Renker2008-01-282-6/+0
| | | | | | | | | | This removes a variable `ccid2hctx_sent' which is incremented but never referenced/read (i.e., dead 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@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* [CCID2]: Disable broken Ack Ratio adaptation algorithmGerrit Renker2008-01-282-6/+21
| | | | | | | | | | | | | | | | | | | | | | | | This comments out a problematic section comprising a half-finished algorithm: - The variable `ccid2hctx_ackloss' is never initialised to a value different from 0 and hence in fact is a read-only constant. - The `arsent' variable counts packets other than Acks (it is incremented for every packet), and there is no test for Ack Loss. - The concept of counting Acks as such leads to a complex calculation, and the calculation at the moment is inconsistent with this concept. The problem is that the number of Acks - rather than the number of windows - is counted, which leads to a complex (cubic/quadratic) expression - this is not even implemented. In its current state, the commented-out algorithm interfers with normal processing by changing Ack Ratio incorrectly, and at the wrong times. A new algorithm is necessary, which will not necessarily use the same variables as used by the unfinished one; hence the old variables have been removed. 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>
* [CCID2]: Larger initial windows also for CCID2Gerrit Renker2008-01-281-5/+15
| | | | | | | | | | | RFC 4341, sec. 5 states that "The cwnd parameter is initialized to at most four packets for new connections, following the rules from [RFC3390]", which is implemented 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>
* [CCID2]: Deadlock and spurious timeouts when Ack Ratio > cwndGerrit Renker2008-01-281-18/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch removes a bug in the current code. I agree with Andrea's comment that there is a problem here but the way it is treated does not fix it. The problem is that whenever Ack Ratio > cwnd, starvation/deadlock occurs: * the receiver will not send an Ack until (Ack Ratio - cwnd) data packets have arrived; * the sender will not send any data packet before the receipt of an Ack advances the send window. The only way that the connection then progresses was via RTO timeout. In one extreme case (bulk transfer), it was observed that this happened for every single packet; i.e. hundreds of packets, each a RTO timeout of 1..3 seconds apart: a transfer which normally would take a fraction of a second thus grew to several minutes. The solution taken by this approach is to observe the relation "Ack Ratio <= cwnd" by using the constraint (1) from RFC 4341, 6.1.2; i.e. set Ack Ratio = ceil(cwnd / 2) and update it whenever either Ack Ratio or cwnd change. This ensures that the deadlock problem can not arise. 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>
* [CCID2]: Don't assign negative values to Ack RatioGerrit Renker2008-01-281-4/+5
| | | | | | | | | | | | | | | Since it makes not sense to assign negative values to Ack Ratio, this patch disallows this possibility. As a consequence, a Bug test for negative Ack Ratio values becomes obsolete. Furthermore, a check against overflow (as Ack Ratio may not exceed 2 bytes, due to RFC 4340, 11.3) has been 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@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* [CCID2]: Fix sequence number arithmetic/comparisonsGerrit Renker2008-01-281-7/+2
| | | | | | | | | This replaces use of normal subtraction with modulo-48 subtraction. 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>
* [CCID2]: Bug in reading Ack VectorsGerrit Renker2008-01-281-1/+1
| | | | | | | | | | | | | | | | | | | In CCID2 the receiver-history is sorted in ascending order of sequence number, but the processing of received Ack Vectors requires the list traversal in the opposite direction. The current code has a bug in this regard: the list traversal is upwards. As a consequence, only Ack Vectors with a run length of 1 will pass, in all other Ack Vectors the remaining (acked) sequence numbers are missed, and may later falsely be identified as lost. Note: This bug is only visible when Ack Ratio > 1, since otherwise the run lengths of Ack Vectors are 0. 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>
* [DCCP]: Remove redundant dependency on IP_DCCPGerrit Renker2008-01-281-3/+1
| | | | | | | | | | | | | | This cleans up the consequences of an earlier patch which introduced the `if IP_DCCP' clause into net/dccp/Kconfig. The CCID Kconfig menu is sourced within this clause; as a consequence, all tests of type `depends on IP_DCCP' are now redundant. 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>
* [DCCP]: Promote CCID2 as default CCIDGerrit Renker2008-01-281-11/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch addresses the following problems: 1. DCCP relies for its proper functioning on having at least one CCID module enabled (as in TCP plugable congestion control). Currently it is possible to disable both CCIDs and thus leave the DCCP module in a compiled, but entirely non-functional state: no sockets can be created when no CCID is available. Furthermore, the protocol is (again like TCP) not intended to be used without CCIDs. Last, a non-empty CCID list is needed for doing CCID feature negotiation. 2. Internally the default CCID that is advertised by the Linux host is set to CCID2 (DCCPF_INITIAL_CCID in include/linux/dccp.h). Disabling CCID2 in the Kconfig menu without changing the defaults leads to a failure `module not found' when trying to load the dccp module (which internally tries to load the default CCID). 3. The specification (RFC 4340, sec. 10) treats CCID2 somewhat like a `minimum common denominator'; the specification says that: * "New connections start with CCID 2 for both endpoints" * "A DCCP implementation intended for general use, such as an implementation in a general-purpose operating system kernel, SHOULD implement at least CCID 2. The intent is to make CCID 2 broadly available for interoperability [...]" Providing CCID2 as minimum-required CCID (like Reno/Cubic in TCP) thus seems reasonable. Hence this patch automatically selects CCID2 when DCCP is enabled. Documentation also added. Discussions with Ian McDonald on this subject are gratefully acknowledged. 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>
* [CCID3]: Inline for moving averageGerrit Renker2008-01-282-20/+14
| | | | | | | | | | | The moving average computation occurs so frequently in the CCID 3 code that it merits an inline function of its own. This is uses a suggestion by Arnaldo as per http://www.mail-archive.com/dccp@vger.kernel.org/msg01662.html 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>
* [CCID3]: Accurately determine idle & application-limited periodsGerrit Renker2008-01-282-10/+10
| | | | | | | | | | | | | This fixes/updates the handling of idle and application-limited periods in CCID3, which currently is broken: there is no detection as to how long a sender has been idle - there is only one flag which is toggled in between function calls. Being obsolete now, the `idle' flag is removed. 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>
* [CCID3]: Ignore trivial amounts of elapsed timeGerrit Renker2008-01-282-11/+1
| | | | | | | | | | | | | | | | | | | | | This patch fixes a previously undiscovered bug; the problem is in computing the elapsed time as the time between `receiving' the packet (i.e. skb enters CCID module) and sending feedback: - there is no layer-processing, queueing, or delay involved, - hence the elapsed time is in the order of 1 function call - this is in the dimension of maximally 50..100usec - which renders the use of elapsed time almost entirely useless. The fix is simply to ignore such trivial amounts of elapsed time. As a further advantage, the now useless elapsed_time field can be removed from the socket, which reduces the socket structure by another four bytes. 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>
* [CCID3]: Revert use of MSS instead of sGerrit Renker2008-01-281-9/+12
| | | | | | | | | | | | | | | | This updates the CCID3 code with regard to two instances of using `MSS' in place of `s': 1. The RFC3390-based initial rate: both rfc3448bis as well as the Faster Restart draft now consistently use `s' instead of MSS. 2. Now agrees with section 4.2 of rfc3448bis: "If the sender is ready to send data when it does not yet have a round trip sample, the value of X is set to s bytes per second, for segment size s [...]" 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>
* [NET]: Convert init_timer into setup_timerPavel Emelyanov2008-01-282-9/+4
| | | | | | | | | | | | | Many-many code in the kernel initialized the timer->function and timer->data together with calling init_timer(timer). There is already a helper for this. Use it for networking code. The patch is HUGE, but makes the code 130 lines shorter (98 insertions(+), 228 deletions(-)). Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* [DCCP]: Spelling fixesJoe Perches2007-12-201-1/+1
| | | | | Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: David S. Miller <davem@davemloft.net>
generated by cgit v1.1 at 2024-12-24 18:32:35 +0000