summaryrefslogtreecommitdiff
path: root/net/dccp
AgeCommit message (Collapse)Author
2010-11-15dccp ccid-2: Schedule Sync as out-of-band mechanismGerrit Renker
The problem with Ack Vectors is that i) their length is variable and can in principle grow quite large, ii) it is hard to predict exactly how large they will be. Due to the second point it seems not a good idea to reduce the MPS; in particular when on average there is enough room for the Ack Vector and an increase in length is momentarily due to some burst loss, after which the Ack Vector returns to its normal/average length. The solution taken by this patch is to subtract a minimum-expected Ack Vector length from the MPS, and to defer any larger Ack Vectors onto a separate Sync - but only if indeed there is no space left on the skb. This patch provides the infrastructure to schedule Sync-packets for transporting (urgent) out-of-band data. Its signalling is quicker than scheduling an Ack, since it does not need to wait for new application data. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
2010-11-15dccp ccid-2: Consolidate Ack-Vector processing within main DCCP moduleGerrit Renker
This aggregates Ack Vector processing (handling input and clearing old state) into one function, for the following reasons and benefits: * all Ack Vector-specific processing is now in one place; * duplicated code is removed; * ensuring sanity: from an Ack Vector point of view, it is better to clear the old state first before entering new state; * Ack Event handling happens mostly within the CCIDs, not the main DCCP module. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
2010-11-15dccp ccid-2: Update code for the Ack Vector input/registration routineGerrit Renker
This patch updates the code which registers new packets as received, using the new circular buffer interface. It contributes a new algorithm which * supports both tail/head pointers and buffer wrap-around and * deals with overflow (head/tail move in lock-step). Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
2010-11-15dccp ccid-2: Algorithm to update buffer stateGerrit Renker
This provides a routine to consistently update the buffer state when the peer acknowledges receipt of Ack Vectors; updating state in the list of Ack Vectors as well as in the circular buffer. While based on RFC 4340, several additional (and necessary) precautions were added to protect the consistency of the buffer state. These additions are essential, since analysis and experience showed that the basic algorithm was insufficient for this task (which lead to problems that were hard to debug). The algorithm now * deals with HC-sender acknowledging to HC-receiver and vice versa, * keeps track of the last unacknowledged but received seqno in tail_ackno, * has special cases to reset the overflow condition when appropriate, * is protected against receiving older information (would mess up buffer state). Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
2010-11-10dccp ccid-2: Implementation of circular Ack Vector buffer with overflow handlingGerrit Renker
This completes the implementation of a circular buffer for Ack Vectors, by extending the current (linear array-based) implementation. The changes are: (a) An `overflow' flag to deal with the case of overflow. As before, dynamic growth of the buffer will not be supported; but code will be added to deal robustly with overflowing Ack Vector buffers. (b) A `tail_seqno' field. When naively implementing the algorithm of Appendix A in RFC 4340, problems arise whenever subsequent Ack Vector records overlap, which can bring the entire run length calculation completely out of synch. (This is documented on http://www.erg.abdn.ac.uk/users/gerrit/dccp/notes/\ ack_vectors/tracking_tail_ackno/ .) (c) The buffer length is now computed dynamically (i.e. current fill level), as the span between head to tail. As a result, dccp_ackvec_pending() is now simpler - the #ifdef is no longer necessary since buf_empty is always true when IP_DCCP_ACKVEC is not configured. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
2010-11-10dccp ccid-2: Separate internals of Ack Vectors from option-parsing codeGerrit Renker
This patch * separates Ack Vector housekeeping code from option-insertion code; * shifts option-specific code from ackvec.c into options.c; * introduces a dedicated routine to take care of the Ack Vector records; * simplifies the dccp_ackvec_insert_avr() routine: the BUG_ON was redundant, since the list is automatically arranged in descending order of ack_seqno. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
2010-11-10dccp ccid-2: Ack Vector interface clean-upGerrit Renker
This patch brings the Ack Vector interface up to date. Its main purpose is to lay the basis for the subsequent patches of this set, which will use the new data structure fields and routines. There are no real algorithmic changes, rather an adaptation: (1) Replaced the static Ack Vector size (2) with a #define so that it can be adapted (with low loss / Ack Ratio, a value of 1 works, so 2 seems to be sufficient for the moment) and added a solution so that computing the ECN nonce will continue to work - even with larger Ack Vectors. (2) Replaced the #defines for Ack Vector states with a complete enum. (3) Replaced #defines to compute Ack Vector length and state with general purpose routines (inlines), and updated code to use these. (4) Added a `tail' field (conversion to circular buffer in subsequent patch). (5) Updated the (outdated) documentation for Ack Vector struct. (6) All sequence number containers now trimmed to 48 bits. (7) Removal of unused bits: * removed dccpav_ack_nonce from struct dccp_ackvec, since this is already redundantly stored in the `dccpavr_ack_nonce' (of Ack Vector record); * removed Elapsed Time for Ack Vectors (it was nowhere used); * replaced semantics of dccpavr_sent_len with dccpavr_ack_runlen, since the code needs to be able to remember the old run length; * reduced the de-/allocation routines (redundant / duplicate tests). Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
2010-10-28dccp ccid-2: Stop pollingGerrit Renker
This updates CCID-2 to use the CCID dequeuing mechanism, converting from previous continuous-polling to a now event-driven mechanism. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-10-28dccp: Refine the wait-for-ccid mechanismGerrit Renker
This extends the existing wait-for-ccid routine so that it may be used with different types of CCID, addressing the following problems: 1) The queue-drain mechanism only works with rate-based CCIDs. If CCID-2 for example has a full TX queue and becomes network-limited just as the application wants to close, then waiting for CCID-2 to become unblocked could lead to an indefinite delay (i.e., application "hangs"). 2) Since each TX CCID in turn uses a feedback mechanism, there may be changes in its sending policy while the queue is being drained. This can lead to further delays during which the application will not be able to terminate. 3) The minimum wait time for CCID-3/4 can be expected to be the queue length times the current inter-packet delay. For example if tx_qlen=100 and a delay of 15 ms is used for each packet, then the application would have to wait for a minimum of 1.5 seconds before being allowed to exit. 4) There is no way for the user/application to control this behaviour. It would be good to use the timeout argument of dccp_close() as an upper bound. Then the maximum time that an application is willing to wait for its CCIDs to can be set via the SO_LINGER option. These problems are addressed by giving the CCID a grace period of up to the `timeout' value. The wait-for-ccid function is, as before, used when the application (a) has read all the data in its receive buffer and (b) if SO_LINGER was set with a non-zero linger time, or (c) the socket is either in the OPEN (active close) or in the PASSIVE_CLOSEREQ state (client application closes after receiving CloseReq). In addition, there is a catch-all case of __skb_queue_purge() after waiting for the CCID. This is necessary since the write queue may still have data when (a) the host has been passively-closed, (b) abnormal termination (unread data, zero linger time), (c) wait-for-ccid could not finish within the given time limit. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-10-28dccp: Extend CCID packet dequeueing interfaceGerrit Renker
This extends the packet dequeuing interface of dccp_write_xmit() to allow 1. CCIDs to take care of timing when the next packet may be sent; 2. delayed sending (as before, with an inter-packet gap up to 65.535 seconds). The main purpose is to take CCID-2 out of its polling mode (when it is network- limited, it tries every millisecond to send, without interruption). The mode of operation for (2) is as follows: * new packet is enqueued via dccp_sendmsg() => dccp_write_xmit(), * ccid_hc_tx_send_packet() detects that it may not send (e.g. window full), * it signals this condition via `CCID_PACKET_WILL_DEQUEUE_LATER', * dccp_write_xmit() returns without further action; * after some time the wait-condition for CCID becomes true, * that CCID schedules the tasklet, * tasklet function calls ccid_hc_tx_send_packet() via dccp_write_xmit(), * since the wait-condition is now true, ccid_hc_tx_packet() returns "send now", * packet is sent, and possibly more (since dccp_write_xmit() loops). Code reuse: the taskled function calls dccp_write_xmit(), the timer function reduces to a wrapper around the same code. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-10-28dccp: Return-value convention of hc_tx_send_packet()Gerrit Renker
This patch reorganises the return value convention of the CCID TX sending function, to permit more flexible schemes, as required by subsequent patches. Currently the convention is * values < 0 mean error, * a value == 0 means "send now", and * a value x > 0 means "send in x milliseconds". The patch provides symbolic constants and a function to interpret return values. In addition, it caps the maximum positive return value to 0xFFFF milliseconds, corresponding to 65.535 seconds. This is possible since in CCID-3/4 the maximum possible inter-packet gap is fixed at t_mbi = 64 sec. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-10-23Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next-2.6Linus Torvalds
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next-2.6: (1699 commits) bnx2/bnx2x: Unsupported Ethtool operations should return -EINVAL. vlan: Calling vlan_hwaccel_do_receive() is always valid. tproxy: use the interface primary IP address as a default value for --on-ip tproxy: added IPv6 support to the socket match cxgb3: function namespace cleanup tproxy: added IPv6 support to the TPROXY target tproxy: added IPv6 socket lookup function to nf_tproxy_core be2net: Changes to use only priority codes allowed by f/w tproxy: allow non-local binds of IPv6 sockets if IP_TRANSPARENT is enabled tproxy: added tproxy sockopt interface in the IPV6 layer tproxy: added udp6_lib_lookup function tproxy: added const specifiers to udp lookup functions tproxy: split off ipv6 defragmentation to a separate module l2tp: small cleanup nf_nat: restrict ICMP translation for embedded header can: mcp251x: fix generation of error frames can: mcp251x: fix endless loop in interrupt handler if CANINTF_MERRF is set can-raw: add msg_flags to distinguish local traffic 9p: client code cleanup rds: make local functions/variables static ... Fix up conflicts in net/core/dev.c, drivers/net/pcmcia/smc91c92_cs.c and drivers/net/wireless/ath/ath9k/debug.c as per David
2010-10-21Merge branch 'master' of ↵David S. Miller
git://git.kernel.org/pub/scm/linux/kernel/git/kaber/nf-next-2.6
2010-10-21tproxy: fix hash locking issue when using port redirection in ↵Balazs Scheidler
__inet_inherit_port() When __inet_inherit_port() is called on a tproxy connection the wrong locks are held for the inet_bind_bucket it is added to. __inet_inherit_port() made an implicit assumption that the listener's port number (and thus its bind bucket). Unfortunately, if you're using the TPROXY target to redirect skbs to a transparent proxy that assumption is not true anymore and things break. This patch adds code to __inet_inherit_port() so that it can handle this case by looking up or creating a new bind bucket for the child socket and updates callers of __inet_inherit_port() to gracefully handle __inet_inherit_port() failing. Reported by and original patch from Stephen Buck <stephen.buck@exinda.com>. See http://marc.info/?t=128169268200001&r=1&w=2 for the original discussion. Signed-off-by: KOVACS Krisztian <hidden@balabit.hu> Signed-off-by: Patrick McHardy <kaber@trash.net>
2010-10-15llseek: automatically add .llseek fopArnd Bergmann
All file_operations should get a .llseek operation so we can make nonseekable_open the default for future file operations without a .llseek pointer. The three cases that we can automatically detect are no_llseek, seq_lseek and default_llseek. For cases where we can we can automatically prove that the file offset is always ignored, we use noop_llseek, which maintains the current behavior of not returning an error from a seek. New drivers should normally not use noop_llseek but instead use no_llseek and call nonseekable_open at open time. Existing drivers can be converted to do the same when the maintainer knows for certain that no user code relies on calling seek on the device file. The generated code is often incorrectly indented and right now contains comments that clarify for each added line why a specific variant was chosen. In the version that gets submitted upstream, the comments will be gone and I will manually fix the indentation, because there does not seem to be a way to do that using coccinelle. Some amount of new code is currently sitting in linux-next that should get the same modifications, which I will do at the end of the merge window. Many thanks to Julia Lawall for helping me learn to write a semantic patch that does all this. ===== begin semantic patch ===== // This adds an llseek= method to all file operations, // as a preparation for making no_llseek the default. // // The rules are // - use no_llseek explicitly if we do nonseekable_open // - use seq_lseek for sequential files // - use default_llseek if we know we access f_pos // - use noop_llseek if we know we don't access f_pos, // but we still want to allow users to call lseek // @ open1 exists @ identifier nested_open; @@ nested_open(...) { <+... nonseekable_open(...) ...+> } @ open exists@ identifier open_f; identifier i, f; identifier open1.nested_open; @@ int open_f(struct inode *i, struct file *f) { <+... ( nonseekable_open(...) | nested_open(...) ) ...+> } @ read disable optional_qualifier exists @ identifier read_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; expression E; identifier func; @@ ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off) { <+... ( *off = E | *off += E | func(..., off, ...) | E = *off ) ...+> } @ read_no_fpos disable optional_qualifier exists @ identifier read_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; @@ ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off) { ... when != off } @ write @ identifier write_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; expression E; identifier func; @@ ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off) { <+... ( *off = E | *off += E | func(..., off, ...) | E = *off ) ...+> } @ write_no_fpos @ identifier write_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; @@ ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off) { ... when != off } @ fops0 @ identifier fops; @@ struct file_operations fops = { ... }; @ has_llseek depends on fops0 @ identifier fops0.fops; identifier llseek_f; @@ struct file_operations fops = { ... .llseek = llseek_f, ... }; @ has_read depends on fops0 @ identifier fops0.fops; identifier read_f; @@ struct file_operations fops = { ... .read = read_f, ... }; @ has_write depends on fops0 @ identifier fops0.fops; identifier write_f; @@ struct file_operations fops = { ... .write = write_f, ... }; @ has_open depends on fops0 @ identifier fops0.fops; identifier open_f; @@ struct file_operations fops = { ... .open = open_f, ... }; // use no_llseek if we call nonseekable_open //////////////////////////////////////////// @ nonseekable1 depends on !has_llseek && has_open @ identifier fops0.fops; identifier nso ~= "nonseekable_open"; @@ struct file_operations fops = { ... .open = nso, ... +.llseek = no_llseek, /* nonseekable */ }; @ nonseekable2 depends on !has_llseek @ identifier fops0.fops; identifier open.open_f; @@ struct file_operations fops = { ... .open = open_f, ... +.llseek = no_llseek, /* open uses nonseekable */ }; // use seq_lseek for sequential files ///////////////////////////////////// @ seq depends on !has_llseek @ identifier fops0.fops; identifier sr ~= "seq_read"; @@ struct file_operations fops = { ... .read = sr, ... +.llseek = seq_lseek, /* we have seq_read */ }; // use default_llseek if there is a readdir /////////////////////////////////////////// @ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier readdir_e; @@ // any other fop is used that changes pos struct file_operations fops = { ... .readdir = readdir_e, ... +.llseek = default_llseek, /* readdir is present */ }; // use default_llseek if at least one of read/write touches f_pos ///////////////////////////////////////////////////////////////// @ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read.read_f; @@ // read fops use offset struct file_operations fops = { ... .read = read_f, ... +.llseek = default_llseek, /* read accesses f_pos */ }; @ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier write.write_f; @@ // write fops use offset struct file_operations fops = { ... .write = write_f, ... + .llseek = default_llseek, /* write accesses f_pos */ }; // Use noop_llseek if neither read nor write accesses f_pos /////////////////////////////////////////////////////////// @ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read_no_fpos.read_f; identifier write_no_fpos.write_f; @@ // write fops use offset struct file_operations fops = { ... .write = write_f, .read = read_f, ... +.llseek = noop_llseek, /* read and write both use no f_pos */ }; @ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier write_no_fpos.write_f; @@ struct file_operations fops = { ... .write = write_f, ... +.llseek = noop_llseek, /* write uses no f_pos */ }; @ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read_no_fpos.read_f; @@ struct file_operations fops = { ... .read = read_f, ... +.llseek = noop_llseek, /* read uses no f_pos */ }; @ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; @@ struct file_operations fops = { ... +.llseek = noop_llseek, /* no read or write fn */ }; ===== End semantic patch ===== Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Julia Lawall <julia@diku.dk> Cc: Christoph Hellwig <hch@infradead.org>
2010-10-12dccp: cosmetics - warning formatGerrit Renker
This omits the redundant "DCCP:" in warning messages, since DCCP_WARN() already echoes the function name, avoiding messages like kernel: [10988.766503] dccp_close: DCCP: ABORT -- 209 bytes unread Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
2010-10-12dccp: schedule an Ack when receiving timestampsGerrit Renker
This schedules an Ack when receiving a timestamp, exploiting the existing inet_csk_schedule_ack() function, saving one case in the `dccp_ack_pending()' function. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
2010-10-12dccp: generalise data-loss conditionIvo Calado
This patch generalises the task of determining data loss from RFC 4340, 7.7.1. Let S_A, S_B be sequence numbers such that S_B is "after" S_A, and let N_B be the NDP count of packet S_B. Then, using modulo-2^48 arithmetic, D = S_B - S_A - 1 is an upper bound of the number of lost data packets, D - N_B is an approximation of the number of lost data packets (there are cases where this is not exact). The patch implements this as dccp_loss_count(S_A, S_B, N_B) := max(S_B - S_A - 1 - N_B, 0) Signed-off-by: Ivo Calado <ivocalado@embedded.ufcg.edu.br> Signed-off-by: Erivaldo Xavier <desadoc@gmail.com> Signed-off-by: Leandro Sales <leandroal@gmail.com> Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
2010-10-12dccp: remove unused argument in CCID tx functionGerrit Renker
This removes the argument `more' from ccid_hc_tx_packet_sent, since it was nowhere used in the entire code. (Btw, this argument was not even used in the original KAME code where the function initially came from; compare the variable moreToSend in the freebsd61-dccp-kame-28.08.2006.patch kept by Emmanuel Lochin.) Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
2010-10-12dccp: merge now-reduced connect_init() functionGerrit Renker
After moving the assignment of GAR/ISS from dccp_connect_init() to dccp_transmit_skb(), the former function becomes very small, so that a merger with dccp_connect() suggests itself. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
2010-10-12dccp: fix the adjustments to AWL and SWLGerrit Renker
This fixes a problem and a potential loophole with regard to seqno/ackno validity: currently the initial adjustments to AWL/SWL are only performed once at the begin of the connection, during the handshake. Since the Sequence Window feature is always greater than Wmin=32 (7.5.2), it is however necessary to perform these adjustments at least for the first W/W' (variables as per 7.5.1) packets in the lifetime of a connection. This requirement is complicated by the fact that W/W' can change at any time during the lifetime of a connection. Therefore it is better to perform that safety check each time SWL/AWL are updated, as implemented by the patch. A second problem solved by this patch is that the remote/local Sequence Window feature values (which set the bounds for AWL/SWL/SWH) are undefined until the feature negotiation has completed. During the initial handshake we have more stringent sequence number protection; the changes added by this patch effect that {A,S}W{L,H} are within the correct bounds at the instant that feature negotiation completes (since the SeqWin feature activation handlers call dccp_update_gsr/gss()). Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
2010-10-06dccp: Kill dead code and add static markers.stephen hemminger
Remove dead code and make some functions static. Compile tested only. Signed-off-by: Stephen Hemminger <shemminger@vyatta.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-09-23net: return operator cleanupEric Dumazet
Change "return (EXPR);" to "return EXPR;" return is not a function, parentheses are not required. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-09-21dccp ccid-3: Remove redundant 'options_received' structGerrit Renker
The `options_received' struct is redundant, since it re-duplicates the existing `p' and `x_recv' fields. This patch removes the sub-struct and migrates the format conversion operations to ccid3_hc_tx_parse_options(). Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
2010-09-21dccp tfrc/ccid-3: computing the loss rate from the Loss Event RateGerrit Renker
This adds a function to take care of the following, separate cases occurring in the computation of the Loss Rate p: * 1/(2^32-1) is mapped into 0% as per RFC 4342, 8.5; * 1/0 is mapped into 100%, the maximum; * to avoid that p = 1/x is rounded down to 0 when x is very large, since this means accidentally re-entering slow-start indicated by p == 0, the minimum resolution value of p is now returned instead; * a bug in ccid3_hc_rx_getsockopt is fixed: 1/0 was mapped into ~0U. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
2010-09-21dccp ccid-3: remove dead statesGerrit Renker
This patch is thanks to an investigation by Leandro Sales de Melo and his colleagues. They worked out two state diagrams which highlight the fact that the xxx_TERM states in CCID-3/4 are in fact not necessary. And this can be confirmed by in turn looking at the code: the xxx_TERM states are only ever set in ccid3_hc_{rx,tx}_exit(): when CCID-3 sets the state to xxx_TERM, it is at a time where no more processing should be going on, hence it is not necessary to introduce a dedicated exit state - this is already implied by unloading the CCID. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
2010-09-21dccp: Replace magic CCID-specific numbers by symbolic constantsGerrit Renker
The constants DCCPO_{MIN,MAX}_CCID_SPECIFIC are nowhere used in the code, but instead for the CCID-specific options numbers are used. This patch unifies the use of CCID-specific option numbers, by adding symbolic names reflecting the definitions in RFC 4340, 10.3. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
2010-09-21dccp: Add packet type information to CCID-specific option parsingGerrit Renker
This 1. adds packet type information to ccid_hc_{rx,tx}_parse_options(). This is necessary, since table 3 in RFC 4340, 5.8 leaves it to the CCIDs to state which options may (not) appear on what packet type. 2. adds such a check for CCID-3's {Loss Event, Receive} Rate as specified in RFC 4340 8.3 ("Receive Rate options MUST NOT be sent on DCCP-Data packets") and 8.5 ("Loss Event Rate options MUST NOT be sent on DCCP-Data packets"). 3. removes an unused argument `idx' from ccid_hc_{rx,tx}_parse_options(). This is also no longer necessary, since the CCID-specific option-parsing routines are passed every single parameter of the type-length-value option encoding. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
2010-09-15dccp ccid-3: Simplify and consolidate tx_parse_optionsGerrit Renker
This simplifies and consolidates the TX option-parsing code: 1. The Loss Intervals option is not currently used, so dead code related to this option is removed. I am aware of no plans to support the option, but if someone wants to implement it (e.g. for inter-op tests), it is better to start afresh than having to also update currently unused code. 2. The Loss Event and Receive Rate options have a lot of code in common (both are 32 bit, both have same length etc.), so this is consolidated. 3. The test against GSR is not necessary, because - on first loading CCID3, ccid_new() zeroes out all fields in the socket; - ccid3_hc_tx_packet_recv() treats 0 and ~0U equivalently, due to pinv = opt_recv->ccid3or_loss_event_rate; if (pinv == ~0U || pinv == 0) hctx->p = 0; - as a result, the sequence number field is removed from opt_recv. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
2010-09-15dccp ccid-3: remove buggy RTT-sampling history lookupGerrit Renker
This removes the RTT-sampling function tfrc_tx_hist_rtt(), since 1. it suffered from complex passing of return values (the return value both indicated successful lookup while the value doubled as RTT sample); 2. when for some odd reason the sample value equalled 0, this triggered a bug warning about "bogus Ack", due to the ambiguity of the return value; 3. on a passive host which has not sent anything the TX history is empty and thus will lead to unwanted "bogus Ack" warnings such as ccid3_hc_tx_packet_recv: server(e7b7d518): DATAACK with bogus ACK-28197148 ccid3_hc_tx_packet_recv: server(e7b7d518): DATAACK with bogus ACK-26641606. The fix is to replace the implicit encoding by performing the steps manually. Furthermore, the "bogus Ack" warning has been removed, since it can actually be triggered due to several reasons (network reordering, old packet, (3) above), hence it is not very useful. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
2010-09-15dccp ccid-3: A lower bound for the inter-packet scheduling algorithmGerrit Renker
This fixes a subtle bug in the calculation of the inter-packet gap and shows that t_delta, as it is currently used, is not needed. The algorithm from RFC 5348, 8.3 below continually computes a send time t_nom, which is initialised with the current time t_now; t_gran = 1E6 / HZ specifies the scheduling granularity, s the packet size, and X the sending rate: t_distance = t_nom - t_now; // in microseconds t_delta = min(t_ipi, t_gran) / 2; // `delta' parameter in microseconds if (t_distance >= t_delta) { reschedule after (t_distance / 1000) milliseconds; } else { t_ipi = s / X; // inter-packet interval in usec t_nom += t_ipi; // compute the next send time send packet now; } Problem: -------- Rescheduling requires a conversion into milliseconds (sk_reset_timer()). The highest jiffy resolution with HZ=1000 is 1 millisecond, so using a higher granularity does not make much sense here. As a consequence, values of t_distance < 1000 are truncated to 0. This issue has so far been resolved by using instead if (t_distance >= t_delta + 1000) reschedule after (t_distance / 1000) milliseconds; This is unnecessarily large, a lower bound is t_delta' = max(t_delta, 1000). And it implies a further simplification: a) when HZ >= 500, then t_delta <= t_gran/2 = 10^6/(2*HZ) <= 1000, so that t_delta' = MAX(1000, t_delta) = 1000 (constant value); b) when HZ < 500, then t_delta = 1/2*MIN(rtt, t_ipi, t_gran) <= t_gran/2, so that 1000 <= t_delta' <= t_gran/2. The maximum error of using a constant t_delta in (b) is less than half a jiffy. Fix: ---- The patch replaces t_delta with a constant, whose value depends on CONFIG_HZ, changing the above algorithm to: if (t_distance >= t_delta') reschedule after (t_distance / 1000) milliseconds; where t_delta' = 10^6/(2*HZ) if HZ < 500, and t_delta' = 1000 otherwise. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
2010-08-30dccp ccid-3: use per-route RTO or TCP RTO as fallbackGerrit Renker
This makes RTAX_RTO_MIN also available to CCID-3, replacing the compile-time RTO lower bound with a per-route tunable value. The original Kconfig option solved the problem that a very low RTT (in the order of HZ) can trigger too frequent and unnecessary reductions of the sending rate. This tunable does not affect the initial RTO value of 2 seconds specified in RFC 5348, section 4.2 and Appendix B. But like the hardcoded Kconfig value, it allows to adapt to network conditions. The same effect as the original Kconfig option of 100ms is now achieved by > ip route replace to unicast 192.168.0.0/24 rto_min 100j dev eth0 (assuming HZ=1000). Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-30dccp ccid-2: Share TCP's minimum RTO codeGerrit Renker
Using a fixed RTO_MIN of 0.2 seconds was found to cause problems for CCID-2 over 802.11g: at least once per session there was a spurious timeout. It helped to then increase the the value of RTO_MIN over this link. Since the problem is the same as in TCP, this patch makes the solution from commit "05bb1fad1cde025a864a90cfeb98dcbefe78a44a" "[TCP]: Allow minimum RTO to be configurable via routing metrics." available to DCCP. This avoids reinventing the wheel, so that e.g. the following works in the expected way now also for CCID-2: > ip route change 10.0.0.2 rto_min 800 dev ath0 Luckily this useful rto_min function was recently moved to net/tcp.h, which simplifies sharing code originating from TCP. Documentation also updated (plus minor whitespace fixes). Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-30tcp/dccp: Consolidate common code for RFC 3390 conversionGerrit Renker
This patch consolidates initial-window code common to TCP and CCID-2: * TCP uses RFC 3390 in a packet-oriented manner (tcp_input.c) and * CCID-2 uses RFC 3390 in packet-oriented manner (RFC 4341). Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-30dccp ccid-2: Remove wrappers around sk_{reset,stop}_timer()Gerrit Renker
This removes the wrappers around the sk timer functions, since not much is gained from using them: the BUG_ON in start_rto_timer will never trigger since that function is called only if: * the RTO timer expires (rto_expire, and then timer_pending() is false); * in tx_packet_sent only if !timer_pending() (BUG_ON is redundant here); * previously in new_ack, after stopping the timer (timer_pending() false). Removing the wrappers also clears the way for eventually replacing the RTO timer with the icsk-retransmission-timer, as it is already part of the DCCP socket. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-30dccp ccid-2: Use u32 timestamps uniformlyGerrit Renker
Since CCID-2 is de facto a mini implementation of TCP, it makes sense to share as much code as possible. Hence this patch aligns CCID-2 timestamping with TCP timestamping. This also halves the space consumption (on 64-bit systems). The necessary include file <net/tcp.h> is already included by way of net/dccp.h. Redundant includes have been removed. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-23dccp ccid-2: Replace broken RTT estimator with better algorithmGerrit Renker
The current CCID-2 RTT estimator code is in parts broken and lags behind the suggestions in RFC2988 of using scaled variants for SRTT/RTTVAR. That code is replaced by the present patch, which reuses the Linux TCP RTT estimator code. Further details: ---------------- 1. The minimum RTO of previously one second has been replaced with TCP's, since RFC4341, sec. 5 says that the minimum of 1 sec. (suggested in RFC2988, 2.4) is not necessary. Instead, the TCP_RTO_MIN is used, which agrees with DCCP's concept of a default RTT (RFC 4340, 3.4). 2. The maximum RTO has been set to DCCP_RTO_MAX (64 sec), which agrees with RFC2988, (2.5). 3. De-inlined the function ccid2_new_ack(). 4. Added a FIXME: the RTT is sampled several times per Ack Vector, which will give the wrong estimate. It should be replaced with one sample per Ack. However, at the moment this can not be resolved easily, since - it depends on TX history code (which also needs some work), - the cleanest solution is not to use the `sent' time at all (saves 4 bytes per entry) and use DCCP timestamps / elapsed time to estimated the RTT, which however is non-trivial to get right (but needs to be done). Reasons for reusing the Linux TCP estimator algorithm: ------------------------------------------------------ Some time was spent to find a better alternative, using basic RFC2988 as a first step. Further analysis and experimentation showed that the Linux TCP RTO estimator is superior to a basic RFC2988 implementation. A summary is on http://www.erg.abdn.ac.uk/users/gerrit/dccp/notes/ccid2/rto_estimator/ In addition, this estimator fared well in a recent empirical evaluation: Rewaskar, Sushant, Jasleen Kaur and F. Donelson Smith. A Performance Study of Loss Detection/Recovery in Real-world TCP Implementations. Proceedings of 15th IEEE International Conference on Network Protocols (ICNP-07), 2007. Thus there is significant benefit in reusing the existing TCP code. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-23dccp ccid-2: Simplify dec_pipe and rearming of RTO timerGerrit Renker
This removes the dec_pipe function and improves the way the RTO timer is rearmed when a new acknowledgment comes in. Details and justification for removal: -------------------------------------- 1) The BUG_ON in dec_pipe is never triggered: pipe is only decremented for TX history entries between tail and head, for which it had previously been incremented in tx_packet_sent; and it is not decremented twice for the same entry, since it is - either decremented when a corresponding Ack Vector cell in state 0 or 1 was received (and then ccid2s_acked==1), - or it is decremented when ccid2s_acked==0, as part of the loss detection in tx_packet_recv (and hence it can not have been decremented earlier). 2) Restarting the RTO timer happens for every single entry in each Ack Vector parsed by tx_packet_recv (according to RFC 4340, 11.4 this can happen up to 16192 times per Ack Vector). 3) The RTO timer should not be restarted when all outstanding data has been acknowledged. This is currently done similar to (2), in dec_pipe, when pipe has reached 0. The patch onsolidates the code which rearms the RTO timer, combining the segments from new_ack and dec_pipe. As a result, the code becomes clearer (compare with tcp_rearm_rto()). Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-23dccp ccid-2: Remove redundant sanity testsGerrit Renker
This removes the ccid2_hc_tx_check_sanity function: it is redundant. Details: The tx_check_sanity function performs three tests: 1) it checks that the circular TX list is sorted - in ascending order of sequence number (ccid2s_seq) - and time (ccid2s_sent), - in the direction from `tail' (hctx_seqt) to `head' (hctx_seqh); 2) it ensures that the entire list has the length seqbufc * CCID2_SEQBUF_LEN; 3) it ensures that pipe equals the number of packets that were not marked `acked' (ccid2s_acked) between `tail' and `head'. The following argues that each of these tests is redundant, this can be verified by going through the code. (1) is not necessary, since both time and GSS increase from one packet to the next, so that subsequent insertions in tx_packet_sent (which advance the `head' pointer) will be in ascending order of time and sequence number. In (2), the length of the list is always equal to seqbufc times CCID2_SEQBUF_LEN (set to 1024) unless allocation caused an earlier failure, because: * at initialisation (tx_init), there is one chunk of size 1024 and seqbufc=1; * subsequent calls to tx_alloc_seq take place whenever head->next == tail in tx_packet_sent; then a new chunk of size 1024 is inserted between head and tail, and seqbufc is incremented by one. To show that (3) is redundant requires looking at two cases. The `pipe' variable of the TX socket is incremented only in tx_packet_sent, and decremented in tx_packet_recv. When head == tail (TX history empty) then pipe should be 0, which is the case directly after initialisation and after a retransmission timeout has occurred (ccid2_hc_tx_rto_expire). The first case involves parsing Ack Vectors for packets recorded in the live portion of the buffer, between tail and head. For each packet marked by the receiver as received (state 0) or ECN-marked (state 1), pipe is decremented by one, so for all such packets the BUG_ON in tx_check_sanity will not trigger. The second case is the loss detection in the second half of tx_packet_recv, below the comment "Check for NUMDUPACK". The first while-loop here ensures that the sequence number of `seqp' is either above or equal to `high_ack', or otherwise equal to the highest sequence number sent so far (of the entry head->prev, as head points to the next unsent entry). The next while-loop ("while (1)") counts the number of acked packets starting from that position of seqp, going backwards in the direction from head->prev to tail. If NUMDUPACK=3 such packets were counted within this loop, `seqp' points to the last acknowledged packet of these, and the "if (done == NUMDUPACK)" block is entered next. The while-loop contained within that block in turn traverses the list backwards, from head to tail; the position of `seqp' is saved in the variable `last_acked'. For each packet not marked as `acked', a congestion event is triggered within the loop, and pipe is decremented. The loop terminates when `seqp' has reached `tail', whereupon tail is set to the position previously stored in `last_acked'. Thus, between `last_acked' and the previous position of `tail', - pipe has been decremented earlier if the packet was marked as state 0 or 1; - pipe was decremented if the packet was not marked as acked. That is, pipe has been decremented by the number of packets between `last_acked' and the previous position of `tail'. As a consequence, pipe now again reflects the number of packets which have not (yet) been acked between the new position of tail (at `last_acked') and head->prev, or 0 if head==tail. The result is that the BUG_ON condition in check_sanity will also not be triggered, hence the test (3) is also redundant. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-23dccp ccid-3: No more CCID control blocks in LISTEN stateGerrit Renker
The CCIDs are activated as last of the features, at the end of the handshake, were the LISTEN state of the master socket is inherited into the server state of the child socket. Thus, the only states visible to CCIDs now are OPEN/PARTOPEN, and the closing states. This allows to remove tests which were previously necessary to protect against referencing a socket in the listening state (in CCID-3), but which now have become redundant. As a further byproduct of enabling the CCIDs only after the connection has been fully established, several typecast-initialisations of ccid3_hc_{rx,tx}_sock can now be eliminated: * the CCID is loaded, so it is not necessary to test if it is NULL, * if it is possible to load a CCID and leave the private area NULL, then this is a bug, which should crash loudly - and earlier, * the test for state==OPEN || state==PARTOPEN now reduces only to the closing phase (e.g. when the node has received an unexpected Reset). Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-23ccid: ccid-2/3 code cosmeticsGerrit Renker
This patch collects cosmetics-only changes to separate these from code changes: * update with regard to CodingStyle and whitespace changes, * documentation: - adding/revising comments, - remove CCID-3 RX socket documentation which is either duplicate or refers to fields that no longer exist, * expand embedded tfrc_tx_info struct inline for consistency, removing indirections via #define. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-07-18net: dccp: fix sign bugKulikov Vasiliy
'gap' is unsigned, so this code is wrong: gap = -new_head; ... if (gap > 0) { ... } Make 'gap' signed. The semantic patch that finds this problem (many false-positive results): (http://coccinelle.lip6.fr/) // <smpl> @ r1 @ identifier f; @@ int f(...) { ... } @@ identifier r1.f; type T; unsigned T x; @@ *x = f(...) ... *x > 0 Signed-off-by: Kulikov Vasiliy <segooon@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-25snmp: add align parameter to snmp_mib_init()Eric Dumazet
In preparation for 64bit snmp counters for some mibs, add an 'align' parameter to snmp_mib_init(), instead of assuming mibs only contain 'unsigned long' fields. Callers can use __alignof__(type) to provide correct alignment. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> CC: Herbert Xu <herbert@gondor.apana.org.au> CC: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> CC: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org> CC: Vlad Yasevich <vladislav.yasevich@hp.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-25dccp: make implementation of Syn-RTT symmetricGerrit Renker
This patch is thanks to Andre Noll who reported the issue and helped testing. The Syn-RTT sampled during the initial handshake currently only works for the client sending the DCCP-Request. TFRC penalizes the absence of an RTT sample with a very slow initial speed (1 packet per second), which delays slow-start significantly, resulting in sluggish performance. This patch mirrors the "Syn RTT" principle by adding a timestamp also onto the DCCP-Response, producing an RTT sample when the (Data)Ack completing the handshake arrives. Also changed the documentation to 'TFRC' since Syn RTTs are also used by CCID-4. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-25dccp: remove unused function argumentGerrit Renker
This removes an unused 'sk' argument from several option-inserting functions. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-10net-next: remove useless union keywordChangli Gao
remove useless union keyword in rtable, rt6_info and dn_route. Since there is only one member in a union, the union keyword isn't useful. Signed-off-by: Changli Gao <xiaosuo@gmail.com> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-02ipv6: Refactor update of IPv6 flowi destination address for srcrt (RH) optionArnaud Ebalard
There are more than a dozen occurrences of following code in the IPv6 stack: if (opt && opt->srcrt) { struct rt0_hdr *rt0 = (struct rt0_hdr *) opt->srcrt; ipv6_addr_copy(&final, &fl.fl6_dst); ipv6_addr_copy(&fl.fl6_dst, rt0->addr); final_p = &final; } Replace those with a helper. Note that the helper overrides final_p in all cases. This is ok as final_p was previously initialized to NULL when declared. Signed-off-by: Arnaud Ebalard <arno@natisbad.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-05-31net/dccp: Use memdup_userJulia Lawall
Use memdup_user when user data is immediately copied into the allocated region. The semantic patch that makes this change is as follows: (http://coccinelle.lip6.fr/) // <smpl> @@ expression from,to,size,flag; position p; identifier l1,l2; @@ - to = \(kmalloc@p\|kzalloc@p\)(size,flag); + to = memdup_user(from,size); if ( - to==NULL + IS_ERR(to) || ...) { <+... when != goto l1; - -ENOMEM + PTR_ERR(to) ...+> } - if (copy_from_user(to, from, size) != 0) { - <+... when != goto l2; - -EFAULT - ...+> - } // </smpl> Signed-off-by: Julia Lawall <julia@diku.dk> Acked-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-05-25Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6Linus Torvalds
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (63 commits) drivers/net/usb/asix.c: Fix pointer cast. be2net: Bug fix to avoid disabling bottom half during firmware upgrade. proc_dointvec: write a single value hso: add support for new products Phonet: fix potential use-after-free in pep_sock_close() ath9k: remove VEOL support for ad-hoc ath9k: change beacon allocation to prefer the first beacon slot sock.h: fix kernel-doc warning cls_cgroup: Fix build error when built-in macvlan: do proper cleanup in macvlan_common_newlink() V2 be2net: Bug fix in init code in probe net/dccp: expansion of error code size ath9k: Fix rx of mcast/bcast frames in PS mode with auto sleep wireless: fix sta_info.h kernel-doc warnings wireless: fix mac80211.h kernel-doc warnings iwlwifi: testing the wrong variable in iwl_add_bssid_station() ath9k_htc: rare leak in ath9k_hif_usb_alloc_tx_urbs() ath9k_htc: dereferencing before check in hif_usb_tx_cb() rt2x00: Fix rt2800usb TX descriptor writing. rt2x00: Fix failed SLEEP->AWAKE and AWAKE->SLEEP transitions. ...
2010-05-25kernel-wide: replace USHORT_MAX, SHORT_MAX and SHORT_MIN with USHRT_MAX, ↵Alexey Dobriyan
SHRT_MAX and SHRT_MIN - C99 knows about USHRT_MAX/SHRT_MAX/SHRT_MIN, not USHORT_MAX/SHORT_MAX/SHORT_MIN. - Make SHRT_MIN of type s16, not int, for consistency. [akpm@linux-foundation.org: fix drivers/dma/timb_dma.c] [akpm@linux-foundation.org: fix security/keys/keyring.c] Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Acked-by: WANG Cong <xiyou.wangcong@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>