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* dccp ccid-2: Phase out the use of boolean Ack Vector sysctlGerrit Renker2008-12-081-5/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This removes the use of the sysctl and the minisock variable for the Send Ack Vector feature, as it now is handled fully dynamically via feature negotiation (i.e. when CCID-2 is enabled, Ack Vectors are automatically enabled as per RFC 4341, 4.). Using a sysctl in parallel to this implementation would open the door to crashes, since much of the code relies on tests of the boolean minisock / sysctl variable. Thus, this patch replaces all tests of type if (dccp_msk(sk)->dccpms_send_ack_vector) /* ... */ with if (dp->dccps_hc_rx_ackvec != NULL) /* ... */ The dccps_hc_rx_ackvec is allocated by the dccp_hdlr_ackvec() when feature negotiation concluded that Ack Vectors are to be used on the half-connection. Otherwise, it is NULL (due to dccp_init_sock/dccp_create_openreq_child), so that the test is a valid one. The activation handler for Ack Vectors is called as soon as the feature negotiation has concluded at the * server when the Ack marking the transition RESPOND => OPEN arrives; * client after it has sent its ACK, marking the transition REQUEST => PARTOPEN. Adding the sequence number of the Response packet to the Ack Vector has been removed, since (a) connection establishment implies that the Response has been received; (b) the CCIDs only look at packets received in the (PART)OPEN state, i.e. this entry will always be ignored; (c) it can not be used for anything useful - to detect loss for instance, only packets received after the loss can serve as pseudo-dupacks. There was a FIXME to change the error code when dccp_ackvec_add() fails. I removed this after finding out that: * the check whether ackno < ISN is already made earlier, * this Response is likely the 1st packet with an Ackno that the client gets, * so when dccp_ackvec_add() fails, the reason is likely not a packet error. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz> Signed-off-by: David S. Miller <davem@davemloft.net>
* dccp: Remove manual influence on NDP Count featureGerrit Renker2008-12-081-3/+1
| | | | | | | | | | | | | | | | | | | | | | | | Updating the NDP count feature is handled automatically now: * for CCID-2 it is disabled, since the code does not use NDP counts; * for CCID-3 it is enabled, as NDP counts are used to determine loss lengths. Allowing the user to change NDP values leads to unpredictable and failing behaviour, since it is then possible to disable NDP counts even when they are needed (e.g. in CCID-3). This means that only those user settings are sensible that agree with the values for Send NDP Count implied by the choice of CCID. But those settings are already activated by the feature negotiation (CCID dependency tracking), hence this form of support is redundant. At startup the initialisation of the NDP count feature uses the default value of 0, which is done implicitly by the zeroing-out of the socket when it is allocated. If the choice of CCID or feature negotiation enables NDP count, this will then be updated via the NDP activation handler. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz> Signed-off-by: David S. Miller <davem@davemloft.net>
* dccp: Processing Confirm optionsGerrit Renker2008-12-011-14/+2
| | | | | | | | | | | | | Analogous to the previous patch, this adds code to interpret incoming Confirm feature-negotiation options. Both functions operate on the feature-negotiation list of either the request_sock (server) or the dccp_sock (client). Thanks to Wei Yongjun for pointing out that it is overly restrictive to check the entire list of confirmed SP values. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz> Signed-off-by: David S. Miller <davem@davemloft.net>
* dccp: Process incoming Change feature-negotiation optionsGerrit Renker2008-12-011-15/+8
| | | | | | | | | | | | | | This adds/replaces code for processing incoming ChangeL/R options. The main difference is that: * mandatory FN options are now interpreted inside the function (there are too many individual cases to do this externally); * the function returns an appropriate Reset code or 0, which is then used to fill in the data for the Reset packet. Old code, which is no longer used or referenced, has been removed. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Signed-off-by: David S. Miller <davem@davemloft.net>
* dccp: Integrate feature-negotiation insertion codeGerrit Renker2008-12-011-12/+21
| | | | | | | | | | | | | | | | The patch implements insertion of feature negotiation at the server (listening and request socket) and the client (connecting socket). In dccp_insert_options(), several statements have been grouped together now to achieve (it is hoped) better efficiency by reducing the number of tests each packet has to go through: - Ack Vectors are sent if the packet is neither a Data or a Request packet; - a previous issue is corrected - feature negotiation options are allowed on DataAck packets (5.8). Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz> Signed-off-by: David S. Miller <davem@davemloft.net>
* dccp: fix warning in net/dccp/options.cIngo Molnar2008-11-251-1/+1
| | | | | | | | | | | | | | | | | this warning: net/dccp/options.c: In function ‘dccp_parse_options’: net/dccp/options.c:67: warning: ‘value’ may be used uninitialized in this function is a bogus GCC warning. The compiler does not recognize the relation between "value" and "mandatory" variables: the code flow can ever reach the "out_invalid_option:" label if 'mandatory' is set to 1, and when 'mandatory' is non-zero, we'll always have 'value' initialized. Help out the compiler by annotating the variable. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: David S. Miller <davem@davemloft.net>
* dccp: Header option insertion routine for feature-negotiationGerrit Renker2008-11-231-60/+31
| | | | | | | | | | | | The patch extends existing code: * Confirm options divide into the confirmed value plus an optional preference list for SP values. Previously only the preference list was echoed for SP values, now the confirmed value is added as per RFC 4340, 6.1; * length and sanity checks are added to avoid illegal memory (or NULL) access. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz> Signed-off-by: David S. Miller <davem@davemloft.net>
* dccp: Support for Mandatory optionsGerrit Renker2008-11-231-0/+15
| | | | | | | | | | Support for Mandatory options is provided by this patch, which will be used by subsequent feature-negotiation patches. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz> Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* dccp: Increase the scope of variable-length htonl/ntohl functionsGerrit Renker2008-11-231-7/+14
| | | | | | | | | | | | | | | This extends the scope of two available functions, encode|decode_value_var, to work up to 6 (8) bytes, to match maximum requirements in the RFC. These functions are going to be used both by general option processing and feature negotiation code, hence declarations have been put into feat.h. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz> Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* dccp: Deprecate Ack Ratio sysctlGerrit Renker2008-11-161-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch deprecates the Ack Ratio sysctl, since * Ack Ratio is entirely ignored by CCID-3 and CCID-4, * Ack Ratio currently doesn't work in CCID-2 (i.e. is always set to 1); * even if it would work in CCID-2, there is no point for a user to change it: - Ack Ratio is constrained by cwnd (RFC 4341, 6.1.2), - if Ack Ratio > cwnd, the system resorts to spurious RTO timeouts (since waiting for Acks which will never arrive in this window), - cwnd is not a user-configurable value. The only reasonable place for Ack Ratio is to print it for debugging. It is planned to do this later on, as part of e.g. dccp_probe. With this patch Ack Ratio is now under full control of feature negotiation: * Ack Ratio is resolved as a dependency of the selected CCID; * if the chosen CCID supports it (i.e. CCID == CCID-2), Ack Ratio is set to the default of 2, following RFC 4340, 11.3 - "New connections start with Ack Ratio 2 for both endpoints"; * what happens then is part of another patch set, since it concerns the dynamic update of Ack Ratio while the connection is in full flight. Thanks to Tomasz Grobelny for discussion leading up to this patch. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* dccp: Limit feature negotiation to connection setup phaseGerrit Renker2008-11-121-18/+0
| | | | | | | | | | | | | | | | | | | | This patch limits feature (capability) negotation to the connection setup phase: 1. Although it is theoretically possible to perform feature negotiation at any time (and RFC 4340 supports this), in practice this is prohibitively complex, as it requires to put traffic on hold for each new negotiation. 2. As a byproduct of restricting feature negotiation to connection setup, the feature-negotiation retransmit timer is no longer required. This part is now mapped onto the protocol-level retransmission. Details indicating why timers are no longer needed can be found on http://www.erg.abdn.ac.uk/users/gerrit/dccp/notes/feature_negotiation/\ implementation_notes.html This patch disables anytime negotiation, subsequent patches work out full feature negotiation support for connection setup. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Signed-off-by: David S. Miller <davem@davemloft.net>
* This reverts "Merge branch 'dccp' of git://eden-feed.erg.abdn.ac.uk/dccp_exp"Gerrit Renker2008-09-091-178/+163
| | | | | | as it accentally contained the wrong set of patches. These will be submitted separately. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
* dccp ccid-2: Separate option parsing from CCID processingGerrit Renker2008-09-041-7/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch replaces an almost identical replication of code: large parts of dccp_parse_options() re-appeared as ccid2_ackvector() in ccid2.c. Apart from the duplication, this caused two more problems: 1. CCIDs should not need to be concerned with parsing header options; 2. one can not assume that Ack Vectors appear as a contiguous area within an skb, it is legal to insert other options and/or padding in between. The current code would throw an error and stop reading in such a case. The patch provides a new data structure and associated list housekeeping. Only small changes were necessary to integrate with CCID-2: data structure initialisation, adapt list traversal routine, and add call to the provided cleanup routine. The latter also lead to fixing the following BUG: CCID-2 so far ignored Ack Vectors on all packets other than Ack/DataAck, which is incorrect, since Ack Vectors can be present on any packet that has an Ack field. Details: -------- * received Ack Vectors are parsed by dccp_parse_options() alone, which passes the result on to the CCID-specific routine ccid_hc_tx_parse_options(); * CCIDs interested in using/decoding Ack Vector information will add code to fetch parsed Ack Vectors via this interface; * a data structure, `struct dccp_ackvec_parsed' is provided as interface; * this structure arranges Ack Vectors of the same skb into a FIFO order; * a doubly-linked list is used to keep the required FIFO code small. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
* dccp ccid-2: Schedule Sync as out-of-band mechanismGerrit Renker2008-09-041-4/+20
| | | | | | | | | | | | | | | | | | | | | | | | The problem with Ack Vectors is that i) their length is variable and can in principle grow quite large, ii) it is hard to predict exactly how large they will be. Due to the second point it seems not a good idea to reduce the MPS; in particular when on average there is enough room for the Ack Vector and an increase in length is momentarily due to some burst loss, after which the Ack Vector returns to its normal/average length. The solution taken by this patch is to subtract a minimum-expected Ack Vector length from the MPS (previous patch), and to defer any larger Ack Vectors onto a separate Sync - but only if indeed there is no space left on the skb. This patch provides the infrastructure to schedule Sync-packets for transporting (urgent) out-of-band data. Its signalling is quicker than scheduling an Ack, since it does not need to wait for new application data. It can thus serve other parts of the DCCP code as well. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
* dccp ccid-2: Algorithm to update buffer stateGerrit Renker2008-09-041-4/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This provides a routine to consistently update the buffer state when the peer acknowledges receipt of Ack Vectors; updating state in the list of Ack Vectors as well as in the circular buffer. While based on RFC 4340, several additional (and necessary) precautions were added to protect the consistency of the buffer state. These additions are essential, since analysis and experience showed that the basic algorithm was insufficient for this task (which lead to problems that were hard to debug). The algorithm now * deals with HC-sender acknowledging to HC-receiver and vice versa, * keeps track of the last unacknowledged but received seqno in tail_ackno, * has special cases to reset the overflow condition when appropriate, * is protected against receiving older information (would mess up buffer state). Note: The older code performed an unnecessary step, where the sender cleared Ack Vector state by parsing the Ack Vector received by the HC-receiver. Doing this was entirely redundant, since * the receiver always puts the full acknowledgment window (groups 2,3 in 11.4.2) into the Ack Vectors it sends; hence the HC-receiver is only interested in the highest state that the HC-sender received; * this means that the acknowledgment number on the (Data)Ack from the HC-sender is sufficient; and work done in parsing earlier state is not necessary, since the later state subsumes the earlier one (see also RFC 4340, A.4). This older interface (dccp_ackvec_parse()) is therefore removed. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
* dccp ccid-2: Implementation of circular Ack Vector buffer with overflow handlingGerrit Renker2008-09-041-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This completes the implementation of a circular buffer for Ack Vectors, by extending the current (linear array-based) implementation. The changes are: (a) An `overflow' flag to deal with the case of overflow. As before, dynamic growth of the buffer will not be supported; but code will be added to deal robustly with overflowing Ack Vector buffers. (b) A `tail_seqno' field. When naively implementing the algorithm of Appendix A in RFC 4340, problems arise whenever subsequent Ack Vector records overlap, which can bring the entire run length calculation completely out of synch. (This is documented on http://www.erg.abdn.ac.uk/users/gerrit/dccp/notes/\ ack_vectors/tracking_tail_ackno/ .) (c) The buffer lengthi is now computed dynamically (i.e. current fill level), as the span between head to tail. As a result, dccp_ackvec_pending() is now simpler - the #ifdef is no longer necessary since buf_empty is always true when IP_DCCP_ACKVEC is not configured. Note on overflow handling: ------------------------- The Ack Vector code previously simply started to drop packets when the Ack Vector buffer overflowed. This means that the userspace application will not be able to receive, only because of an Ack Vector storage problem. Furthermore, overflow may be transient, so that applications may later recover from the overflow. Recovering from dropped packets is more difficult (e.g. video key frames). Hence the patch uses a different policy: when the buffer overflows, the oldest entries are subsequently overwritten. This has a higher chance of recovery. Details are on http://www.erg.abdn.ac.uk/users/gerrit/dccp/notes/ack_vectors/ Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
* dccp ccid-2: Separate internals of Ack Vectors from option-parsing codeGerrit Renker2008-09-041-0/+60
| | | | | | | | | | | 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>
* dccp: Schedule an Ack when receiving timestampsGerrit Renker2008-09-041-0/+2
| | | | | | | | 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>
* dccp: Replace magic CCID-specific numbers by symbolic constantsGerrit Renker2008-09-041-10/+3
| | | | | | | | | | 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>
* dccp: Add packet type information to CCID-specific option parsingGerrit Renker2008-09-041-12/+4
| | | | | | | | | | | | | | | | | | | This patch ... 1. adds packet type information to ccid_hc_{rx,tx}_parse_options(). This is necessary, since table 3 in RFC 4340, 5.8 leaves it to the CCIDs to state which options may (not) appear on what packet type. 2. adds such a check for CCID-3's {Loss Event, Receive} Rate as specified in RFC 4340 8.3 ("Receive Rate options MUST NOT be sent on DCCP-Data packets") and 8.5 ("Loss Event Rate options MUST NOT be sent on DCCP-Data packets"). 3. removes an unused argument `idx' from ccid_hc_{rx,tx}_parse_options(). This is also no longer necessary, since the CCID-specific option-parsing routines are passed every single parameter of the type-length-value option encoding. Also added documentation and made argument naming scheme consistent. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
* dccp: Debugging functions for feature negotiationGerrit Renker2008-09-041-4/+0
| | | | | | | | | | | | | | | Since all feature-negotiation processing now takes place in feat.c, functions for producing verbose debugging output are concentrated there. New functions to print out values, entry records, and options are provided, and also a macro is defined to not always have the function name in the output line. Thanks a lot to Wei Yongjun and Giuseppe Galeota for help with errors in an earlier revision of this patch. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
* dccp: Initialisation and type-checking of feature sysctlsGerrit Renker2008-09-041-4/+0
| | | | | | | | | | | | | | | | | | | | | | | | This patch takes care of initialising and type-checking sysctls related to feature negotiation. Type checking is important since some of the sysctls now directly act on the feature-negotiation process. The sysctls are initialised with the known default values for each feature. For the type-checking the value constraints from RFC 4340 are used: * Sequence Window uses the specified Wmin=32, the maximum is ulong (4 bytes), tested and confirmed that it works up to 4294967295 - for Gbps speed; * Ack Ratio is between 0 .. 0xffff (2-byte unsigned integer); * CCIDs are between 0 .. 255; * request_retries, retries1, retries2 also between 0..255 for good measure; * tx_qlen is checked to be non-negative; * sync_ratelimit remains as before. Further changes: ---------------- Performed s@sysctl_dccp_feat@sysctl_dccp@g since the sysctls are now in feat.c. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
* dccp ccid-2: Phase out the use of boolean Ack Vector sysctlGerrit Renker2008-09-041-5/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This removes the use of the sysctl and the minisock variable for the Send Ack Vector feature, which is now handled fully dynamically via feature negotiation; i.e. when CCID2 is enabled, Ack Vectors are automatically enabled (as per RFC 4341, 4.). Using a sysctl in parallel to this implementation would open the door to crashes, since much of the code relies on tests of the boolean minisock / sysctl variable. Thus, this patch replaces all tests of type if (dccp_msk(sk)->dccpms_send_ack_vector) /* ... */ with if (dp->dccps_hc_rx_ackvec != NULL) /* ... */ The dccps_hc_rx_ackvec is allocated by the dccp_hdlr_ackvec() when feature negotiation concluded that Ack Vectors are to be used on the half-connection. Otherwise, it is NULL (due to dccp_init_sock/dccp_create_openreq_child), so that the test is a valid one. The activation handler for Ack Vectors is called as soon as the feature negotiation has concluded at the * server when the Ack marking the transition RESPOND => OPEN arrives; * client after it has sent its ACK, marking the transition REQUEST => PARTOPEN. Adding the sequence number of the Response packet to the Ack Vector has been removed, since (a) connection establishment implies that the Response has been received; (b) the CCIDs only look at packets received in the (PART)OPEN state, i.e. this entry will always be ignored; (c) it can not be used for anything useful - to detect loss for instance, only packets received after the loss can serve as pseudo-dupacks. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
* dccp: Remove manual influence on NDP Count featureGerrit Renker2008-09-041-3/+1
| | | | | | | | | | | | | | | | | | | | | | | Updating the NDP count feature is handled automatically now: * for CCID-2 it is disabled, since the code does not use NDP counts; * for CCID-3 it is enabled, as NDP counts are used to determine loss lengths. Allowing the user to change NDP values leads to unpredictable and failing behaviour, since it is then possible to disable NDP counts even when they are needed (e.g. in CCID-3). This means that only those user settings are sensible that agree with the values for Send NDP Count implied by the choice of CCID. But those settings are already activated by the feature negotiation (CCID dependency tracking), hence this form of support is redundant. At startup the initialisation of the NDP count feature is with the default value of 0, which is done implicitly by the zeroing-out of the socket when it is allocated. If the choice of CCID or feature negotiation enables NDP count, this will then be updated via the NDP activation handler. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
* dccp: Processing Confirm optionsGerrit Renker2008-09-041-14/+2
| | | | | | | | | | | | Analogous to the previous patch, this adds code to interpret incoming Confirm feature-negotiation options. Both functions operate on the feature-negotiation list of either the request_sock (server) or the dccp_sock (client). Thanks to Wei Yongjun for pointing out that it is overly restrictive to check the entire list of confirmed SP values. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
* dccp: Process incoming Change feature-negotiation optionsGerrit Renker2008-09-041-15/+8
| | | | | | | | | | | | | This adds/replaces code for processing incoming ChangeL/R options. The main difference is that: * mandatory FN options are now interpreted inside the function (there are too many individual cases to do this externally); * the function returns an appropriate Reset code or 0, which is then used to fill in the data for the Reset packet. Old code, which is no longer used or referenced, has been removed. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
* dccp: Integrate feature-negotiation insertion codeGerrit Renker2008-09-041-12/+21
| | | | | | | | | | | | | | | The patch implements insertion of feature negotiation at the server (listening and request socket) and the client (connecting socket). In dccp_insert_options(), several statements have been grouped together now to achieve (I hope) better efficiency by reducing the number of tests each packet has to go through: - Ack Vectors are sent if the packet is neither a Data or a Request packet; - a previous issue is corrected - feature negotiation options are allowed on DataAck packets (5.8). Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
* dccp: Header option insertion routine for feature-negotiationGerrit Renker2008-09-041-60/+31
| | | | | | | | | | | The patch extends existing code: * Confirm options divide into the confirmed value plus an optional preference list for SP values. Previously only the preference list was echoed for SP values, now the confirmed value is added as per RFC 4340, 6.1; * length and sanity checks are added to avoid illegal memory (or NULL) access. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
* dccp: Support for Mandatory optionsGerrit Renker2008-09-041-0/+15
| | | | | | | | | Support for Mandatory options is provided by this patch, which will be used by subsequent feature-negotiation patches. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz> Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* dccp: Increase the scope of variable-length htonl/ntohl functionsGerrit Renker2008-09-041-7/+14
| | | | | | | | | | | | This extends the scope of two available functions, encode|decode_value_var, to work up to 6 (8) bytes, to match maximum requirements in the RFC. These functions are going to be used both by general option processing and feature negotiation code, hence declarations have been put into feat.h. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz> Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* dccp: Deprecate Ack Ratio sysctlGerrit Renker2008-09-041-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | This patch deprecates the Ack Ratio sysctl, since * Ack Ratio is entirely ignored by CCID-3 and CCID-4, * Ack Ratio currently doesn't work in CCID-2 (i.e. is always set to 1); * even if it would work in CCID-2, there is no point for a user to change it: - Ack Ratio is constrained by cwnd (RFC 4341, 6.1.2), - if Ack Ratio > cwnd, the system resorts to spurious RTO timeouts (since waiting for Acks which will never arrive in this window), - cwnd is not a user-configurable value. The only reasonable place for Ack Ratio is to print it for debugging. It is planned to do this later on, as part of e.g. dccp_probe. With this patch Ack Ratio is now under full control of feature negotiation: * Ack Ratio is resolved as a dependency of the selected CCID; * if the chosen CCID supports it (i.e. CCID == CCID-2), Ack Ratio is set to the default of 2, following RFC 4340, 11.3 - "New connections start with Ack Ratio 2 for both endpoints"; * what happens then is part of another patch set, since it concerns the dynamic update of Ack Ratio while the connection is in full flight. Thanks to Tomasz Grobelny for discussion leading up to this patch. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
* dccp: Limit feature negotiation to connection setup phaseGerrit Renker2008-09-041-18/+0
| | | | | | | | | | | | | | | | | | This patch starts the new implementation of feature negotiation: 1. Although it is theoretically possible to perform feature negotiation at any time (and RFC 4340 supports this), in practice this is prohibitively complex, as it requires to put traffic on hold for each new negotiation. 2. As a byproduct of restricting feature negotiation to connection setup, the feature-negotiation retransmit timer is no longer required. This part is now mapped onto the protocol-level retransmission. Details indicating why timers are no longer needed can be found on http://www.erg.abdn.ac.uk/users/gerrit/dccp/notes/feature_negotiation/\ implementation_notes.html This patch disables anytime negotiation, subsequent patches work out full feature negotiation support for connection setup. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
* dccp: Fill in the Data fields for "Option Error" ResetsGerrit Renker2008-09-041-0/+3
| | | | | | | | This updates the use of the `out_invalid_option' label, which produces a Reset (code 5, "Option Error"), to fill in the Data1...Data3 fields as specified in RFC 4340, 5.6. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
* dccp: Silently ignore options with nonsensical lengthsGerrit Renker2008-09-041-4/+6
| | | | | | | | | | | | | | | | | | | This updates the option-parsing code with regard to RFC 4340, 5.8: "[..] options with nonsensical lengths (length byte less than two or more than the remaining space in the options portion of the header) MUST be ignored, and any option space following an option with nonsensical length MUST likewise be ignored." Hence in the following cases erratic options will be ignored: 1. The type byte of a multi-byte option is the last byte of the header options (i.e. effective option length of 1). 2. The value of the length byte is less than the minimum 2. This has been changed from previously 3: although no multi-byte option with a length less than 3 yet exists (cf. table 3 in 5.8), a length of 2 is valid. (The switch-statement in dccp_parse has further per-option length checks.) 3. The option length exceeds the length of the remaining option space. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
* dccp: Upgrade NDP count from 3 to 6 bytesGerrit Renker2008-07-131-6/+8
| | | | | | | | RFC 4340, 7.7 specifies up to 6 bytes for the NDP Count option, whereas the code is currently limited to up to 3 bytes. This seems to be a relict of an earlier draft version and is brought up to date by the patch. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
* dccp ccid-2: Bug-Fix - Ack Vectors need to be ignored on request socketsGerrit Renker2008-06-111-1/+3
| | | | | | | | | | | | | | | | | | | | | This fixes an oversight from an earlier patch, ensuring that Ack Vectors are not processed on request sockets. The issue is that Ack Vectors must not be parsed on request sockets, since the Ack Vector feature depends on the selection of the (TX) CCID. During the initial handshake the CCIDs are undefined, and so RFC 4340, 10.3 applies: "Using CCID-specific options and feature options during a negotiation for the corresponding CCID feature is NOT RECOMMENDED [...]" And it is not even possible: when the server receives the Request from the client, the CCID and Ack vector features are undefined; when the Ack finalising the 3-way hanshake arrives, the request socket has not been cloned yet into a full socket. (This order is necessary, since otherwise the newly created socket would have to be destroyed whenever an option error occurred - a malicious hacker could simply send garbage options and exploit this.) Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
* [DCCP]: Ignore feature negotiation on Data packetsGerrit Renker2008-01-281-1/+5
| | | | | | | | | | | | | | This implements [RFC 4340, p. 32]: "any feature negotiation options received on DCCP-Data packets MUST be ignored". Also added a FIXME for further processing, since the code currently (wrongly) classifies empty Confirm options as invalid - this needs to be resolved in a separate patch. 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]: Support inserting options during the 3-way handshakeGerrit Renker2008-01-281-10/+22
| | | | | | | | | | | | | | | | | This provides a separate routine to insert options during the initial handshake. The main purpose is to conduct feature negotiation, for the moment the only user is the timestamp echo needed for the (CCID3) handshake RTT sample. Padding of options has been put into a small separate routine, to be shared among the two functions. This could also be used as a generic routine to finish inserting options. Also removed an `XXX' comment since its content was obvious. 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]: Handle timestamps on Request/Response exchange separatelyGerrit Renker2008-01-281-20/+36
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In DCCP, timestamps can occur on packets anytime, CCID3 uses a timestamp(/echo) on the Request/Response exchange. This patch addresses the following situation: * timestamps are recorded on the listening socket; * Responses are sent from dccp_request_sockets; * suppose two connections reach the listening socket with very small time in between: * the first timestamp value gets overwritten by the second connection request. This is not really good, so this patch separates timestamps into * those which are received by the server during the initial handshake (on dccp_request_sock); * those which are received by the client or the client after connection establishment. As before, a timestamp of 0 is regarded as indicating that no (meaningful) timestamp has been received (in addition, a warning message is printed if hosts send 0-valued timestamps). The timestamp-echoing now works as follows: * when a timestamp is present on the initial Request, it is placed into dreq, due to the call to dccp_parse_options in dccp_v{4,6}_conn_request; * when a timestamp is present on the Ack leading from RESPOND => OPEN, it is copied over from the request_sock into the child cocket in dccp_create_openreq_child; * timestamps received on an (established) dccp_sock are treated as before. Since Elapsed Time is measured in hundredths of milliseconds (13.2), the new dccp_timestamp() function is used, as it is expected that the time between receiving the timestamp and sending the timestamp echo will be very small against the wrap-around time. As a byproduct, this allows smaller timestamping-time fields. Furthermore, inserting the Timestamp Echo option has been taken out of the block starting with '!dccp_packet_without_ack()', since Timestamp Echo can be carried on any packet (5.8 and 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@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* [DCCP]: Allow to parse options on Request SocketsGerrit Renker2008-01-281-11/+23
| | | | | | | | | | | | | | | | The option parsing code currently only parses on full sk's. This causes a problem for options sent during the initial handshake (in particular timestamps and feature-negotiation options). Therefore, this patch extends the option parsing code with an additional argument for request_socks: if it is non-NULL, options are parsed on the request socket, otherwise the normal path (parsing on the sk) is used. Subsequent patches, which implement feature negotiation during connection setup, make use of this facility. 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]: Ignore Ack Vectors / Elapsed Time on DCCP-Request alsoGerrit Renker2008-01-281-7/+6
| | | | | | | | | | | Small update with regard to RFC 4340 (references added as documentation): on Requests, Ack Vectors / Elapsed Time should be ignored. Length handling of Elapsed Time also simplified. 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]: Unaligned pointer accessGerrit Renker2007-10-241-11/+22
| | | | | | | | | | | | | | | | This fixes `unaligned (read) access' errors of the type Kernel unaligned access at TPC[100f970c] dccp_parse_options+0x4f4/0x7e0 [dccp] Kernel unaligned access at TPC[1011f2e4] ccid3_hc_tx_parse_options+0x1ac/0x380 [dccp_ccid3] Kernel unaligned access at TPC[100f9898] dccp_parse_options+0x680/0x880 [dccp] by using the get_unaligned macro for parsing options. Commiter note: Preserved the sparse __be{16,32} annotations. 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>
* [DCCP]: Wrong format in printkGerrit Renker2007-10-101-1/+1
| | | | | | | | The elapsed time uses u32, but printk was using %d, not %u. 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>
* [DCCP]: Tidy-up -- minisock initialisationGerrit Renker2007-10-101-10/+0
| | | | | | | | | | | | | | | | This * removes a declaration of a non-existent function __dccp_minisock_init; * shifts the initialisation function dccp_minisock_init() from options.c to minisocks.c, where it is more naturally expected to be. 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]: Provide 10s of microsecond timesourceGerrit Renker2007-10-101-1/+1
| | | | | | | | | | | 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>
* [DCCP]: Nuke dccp_timestamp and dccps_epoch, not used anymoreArnaldo Carvalho de Melo2007-10-101-16/+0
| | | | | Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* [DCCP] options: convert dccp_insert_option_timestamp to ktime_tArnaldo Carvalho de Melo2007-10-101-5/+1
| | | | | Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* [DCCP]: Convert dccps_timestamp_time to ktime_tArnaldo Carvalho de Melo2007-10-101-8/+5
| | | | | Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* [DCCP]: Debug statements for Elapsed Time optionGerrit Renker2007-04-251-2/+6
| | | | | | | | | | 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>
* [DCCP]: Sample RTT from SYN exchangeGerrit Renker2007-04-251-0/+8
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