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* lib: Fix buffer allocation when retransmitting0.19.0Dimitri Staessens2022-03-114-18/+47
| | | | | | | | | | | | | | | The timerwheel was retransmitting packets and the error check for negative values of the rbuff allocation was instead checking for non-zero values, causing a buffer allocation to succeed but the program to continue down the unhappy path leaving that packet stuck in the buffer unattended. Also fixes wrongly scheduled retransmissions that cause packet storms. FRCP is much more stable now. Still needs some work for high bandwidth-delay products (fast-retransmit). Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* ipdpd: Pass MPL to application at flow_allocationDimitri Staessens2022-03-083-8/+23
| | | | | | | | | | | | The maximum packet lifetime (MPL) is a property of the flow that needs to be passed to the reliable transmission protocol (FRCP) for its correct operation. Previously, the value of MPL was set fixed as one of the (fixed) Delta-t parameters. This patch makes the MPL a property of the layer, and it can now be set per layer-type at build time. This is a step towards a proper MPL estimator in the flow allocator. Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* lib: Pass Delta-t params to frcti_create()Dimitri Staessens2022-03-082-9/+9
| | | | | | | | | The parameters were set directly from the build configs. A first step to making FRCP configurable at runtime, is to pass the parameters to the frcti_create() function. Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* lib: Fix RTT estimator invocation in FRCTDimitri Staessens2022-03-031-1/+1
| | | | | | | The notorious off-by-one hit again. Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* lib: Fix underflow in keepalive timerDimitri Staessens2022-03-031-1/+1
| | | | | | | If the keepalive would underflow if set to 1-3 ms. Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* lib: Flag all flows down as the IRMd exitsDimitri Staessens2022-03-033-13/+26
| | | | | | | | | | | | | | On exit of the IRMd all flows will now be flagged as down, so external applications will not hang anymore. Note: reads keep work from flows that are down until there are no more remaining packets in the buffer, but no more packets can be written. When the RIB is used, the external application may exit a bit later than the IRMd, so I added a brief sleep before the IRMd tries to remove the fuse main directory. Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* lib: Fix lock reversal in timerwheelDimitri Staessens2022-03-031-5/+0
| | | | | | | | | There was a lock reversal in the timerwheel. There still is a thorough revision needed of the locking in dev.c after the FRCP logic is completed and tuned. Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* lib: Cleanup RIB mount nameDimitri Staessens2022-03-031-1/+3
| | | | | | | | | | IPCPs would call rib_fini() twice, once after cleaning up their managed RIB, and once again for the program-generic RIB, which is not initialized for IPCPs. rib_fini() checked if the mount name was valid, but it didn't unset it after execution. Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* lib: Check return value of rib_initDimitri Staessens2022-03-031-1/+6
| | | | | | | The rib_init return value wasn't checked. Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* lib: Encrypt bare FRCP messages on encrypted flowsDimitri Staessens2022-03-033-44/+29
| | | | | | | | Bare FRCP messages (ACKs without data, Rendez-vous packets) were not encrypted on encrypted flows, causing the receiver to fail decryption. Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* lib: Make flow liveness timeout configurableDimitri Staessens2022-03-033-28/+57
| | | | | | | | | The qosspec_t now has a timeout value that sets the timeout value of the flow. Flows with a peer that has timed out will now return -EFLOWPEER on flow_read() or flow_write(). Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* lib: Remove dead code in timerwheelDimitri Staessens2022-03-031-6/+0
| | | | | | | The checked condition can't happen. Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* lib: Add initial flow liveness monitoringDimitri Staessens2022-02-243-23/+163
| | | | | | | | | | | | | | | | | | This adds flow liveness monitoring for flows, with a fixed timeout of 120s. I will make it configurable at flow allocation later on (timeout needs to be communicated to the peer). If one peer dies, or doesn't call any IPC calls (flow_write/flow_read/fevent) it will stop sending keepalives and the other peer's read/writes will error on an -EFLOWDOWN after the timeout expires. Packets without a payload (0 length packets) are interpreted as keepalive packets for the flow. They can be sent from any application, but they will not trigger a message read at the receiver side (0 as a return value on flow_read indicates a previous partial read has completed at exactly the buffer size). Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* lib: Maintain a list of flows in flow_setDimitri Staessens2022-02-241-26/+99
| | | | | | | | | The flow_set will now keep a list of the flows in the set, this makes it more efficient to iterate over the flows. Extending the public API for fset_t with an iterator will also be useful. Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* lib: Handle FLOWDOWN during blocking readDimitri Staessens2022-02-211-3/+7
| | | | | | | | | | The blocking read from the rbuff was not correctly handling flow down states, returning a valid index. The attempt to fetch the header then failed on an assertion. The blocking read will now return -EFLOWDOWN if the flow is marked down by the IPCP. Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* ipcpd: Fix free in fail path of readdirDimitri Staessens2022-02-171-0/+9
| | | | | | | | | The free of the buffer in the failure path of the readdir RIB functions was taking the wrong pointer in a couple of places. The FRCT RIB readdir was missing error handling for malloc and strdup. Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* lib: Don't use pointer to set FRCT flagsDimitri Staessens2021-12-291-5/+4
| | | | | | | | | | | | | | | | | | The fccntl call FRCTSFLAGS was using a pointer to a flags so set flags, which should just be a regular uint16_t. For instance, the FRCTLINGER flags can now be turned off using fccntl(fd, FRCTSFLAGS, FRCTFRESCNTL | FRCTFRTX) leaving only resource control (flow control, FRCTFRESCNTL) and retransmission enabled. Note that retransmission (FRCTFRTX) can't be enabled or disabled on a live flow, it will be set on flow allocation. Updates the man page for fccntl to add these FRCT options. Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* lib: Ease lock in timerwheel0.18.4Dimitri Staessens2021-12-221-2/+2
| | | | | | | It was taking a write lock when a read lock was sufficient. Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* lib: Fix waiting for FRCT at deallocationDimitri Staessens2021-12-221-6/+6
| | | | | | | | | | This is a fix to wait for outstanding retransmissions when a flow is deallocated. Instead of waiting the full timeout, it will now wait in the same tic increments used within FRCT. Bit of a stopgap at the moment, FRCT and the flows are in need of a serious refactor. Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* lib: Add missing rwlock unlock in FRCTDimitri Staessens2021-12-221-2/+4
| | | | | | | There was a missing unlock in FRCT. Also fixes some indentation. Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* lib: Fix flow dealloc after expired FRCT timeoutDimitri Staessens2021-12-221-0/+1
| | | | | | | | | | If the timeout is already expired, the wait variable would be negative and return a negative value for the __frcti_dealloc function, thinking that the timeout was not expired causing an unnecessary wait even if all packets are acknowledged. Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* lib: Set initial sender rwe to sender seqnoDimitri Staessens2021-12-221-1/+1
| | | | | | | | | | | The initial sender right window edge (indicating acknowledged packet sequence number) was initialized to seqno - 1. This should be the same as seqno, since we acknowledge with the next expected sequence number. It also indicates that a flow without traffic has no outstanding acknowledgements. Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* lib: Remove old rib_fini codeDimitri Staessens2021-12-061-3/+0
| | | | | | | | There was some leftover code in dev.c wrt to the process RIB that is not needed anymore. Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* lib: Fix undefined behaviour in sha3Dimitri Staessens2021-12-061-2/+1
| | | | | | | | | Arithmetic with NULL pointers is undefined behaviour. Caught by clang 13. Fixed by using uintptr_t, which is guaranteed to be the size of a pointer. Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* lib: Don't initialize process RIB for IPCPsDimitri Staessens2021-07-102-10/+5
| | | | | | | | | | | | | This will skip rib_init() at __init() for IPCPs (or at least, processes that have "ipcpd" in the executable name). The previous code tried to unmount the generic mount and then remount under the ipcp name, but it often failed because fuse_mount() is asynchronous and the mount was not up at the time of the unmount() call. Renaming the mount instead of unmounting failed for the same reason. This is a better fix for now. Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* lib: Application RIB with FRCT statisticsDimitri Staessens2021-06-305-17/+173
| | | | | | | | | | Application flows can now be monitored from the RIB, exposing FRCT statistics (window edges, retransmission timeout, rtt estimate, etc). Application RIB requires user permissions to be able to access /dev/fuse. Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* lib: Pass full path for RIB entriesDimitri Staessens2021-06-291-10/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | The read functions for the RIB will now receive the full path, instead of only the entry name. For IPCPs, we organized the RIB in an /<ipcp>/<component>/entries structure with a directory per component, so we don't need the full path at this point. For process flow information, it's a lot more convenient to organize it the following way /<pid>/<fd>/stat We can then register/unregister the flow descriptor when the frct instance is created, and for getting the stats, we'd know the flow descriptor from the fuse file path. If we would create a file per flow instead of a directory per flow, something like /<pid>/flows/<fd> we'd need to do additional bookkeeping to list the contents of that directory (we would need to track all flows with an active FRCT instance), that fuse knows because it tracks the directories. Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* lib: Remove struct stat from RIB APIDimitri Staessens2021-06-281-5/+14
| | | | | | | | | | The RIB API had a struct stat in the getattr() function, which made all components that exposed variables via the RIB dependent on <sys/stat.h>. The rib now has its own struct rib_attr to set attributes such as size and last modified time. Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* build: Fix compilation with fuse (RIB) on FreeBSDDimitri Staessens2021-06-281-4/+5
| | | | | | | | | | | Compilation failed on FreeBSD 14 with fuse enabled because of some missing definitions. __XSI_VISIBLE must be set before including <ouroboros/rib.h> for some definitions in <sys/stat.h>. FreeBSD doesn't know the MSG_CONFIRM flag to sendto() or CLOCK_REALTIME_COARSE, which are Linux-specific. Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* lib, ipcpd, irmd: Wrap pthread unlocks for cleanupDimitri Staessens2021-06-2310-32/+23
| | | | | | | | | | | | This add an ouroboros/pthread.h header that wraps the pthread_..._unlock() functions for cleanup using pthread_cleanup_push() as this casting is not safe (and there were definitely bad casts in the code). The close() function is now also wrapped for cleanup in ouroboros/sockets.h. This allows enabling more compiler checks. Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* lib: Bypass assertion in shm_rdrbuff0.18.1Dimitri Staessens2021-06-211-1/+1
| | | | | | | | | This assert() causes ipcpd and subsequent irmd abort() when shutting down debug builds. Should be fixed some day when other components are more robust (frct retransmissions and routing). Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* ipcpd: Move RIB initialization to common groundDimitri Staessens2021-06-211-0/+6
| | | | | | | | | | | | | | This moves Resource Information Base (RIB) initialization into the ipcp_init() function, so all IPCPs initialize a RIB. The RIB not shows some common IPCP information, such as the IPCP name, IPCP state and the layer name if the IPCP is part of a layer. The initialization of the hash algorithm and layer name was moved out of the common ipcp source because IPCPs may only know this information after enrollment. Some IPCPs were not even storing this information. Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* build: Remove raptor IPCPDimitri Staessens2021-03-281-1/+1
| | | | | | | | | | This removes the raptor IPCP. The code hasn't been updated for a while, and wouldn't compile. Raptor served its purpose as a PoC for Ouroboros-over-Ethernet-Layer-1, but giving the extreme niche hardware needed to run it, it's not worth maintaining this anymore. Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* ipcpd: Single UDP port for the ipcpd-udp0.18.0Dimitri Staessens2021-01-032-8/+5
| | | | | | | | | | | | | | | | | | The UDP layer will now use a single (configurable) UDP port, default 3435. This makes it easer to allocate flows as a client from behind a NAT firewall without having to configure port forwarding rules. So basically, from now on Ouroboros traffic is transported over a bidirectional <src><port>:<dst><port> UDP tunnel. The reason for not using/allowing different client/server ports is that it would require reading from different sockets using select() or something similar, but since we need the EID anyway (mgmt packets arrive on the same server UDP port), there's not a lot of benefit in doing it. Now the operation is similar to the ipcpd-eth, with the port somewhat functioning as a "layer name", where in UDP, the Ethertype functions as a "layer name". Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* build: Update email addressesDimitri Staessens2021-01-0339-78/+78
| | | | | | | | The ugent email addresses are shut down, updated to Ouroboros mail addresses. Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* build: Update copyright to 2021Dimitri Staessens2021-01-0340-40/+40
| | | | | | | Happy New Year, Ouroboros! Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* lib: Fix flow_accept without opensslDimitri Staessens2020-12-122-5/+7
| | | | | | | | DH key creation was returning -ECRYPT if opennssl is not installed, instead of success (0). Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* lib: Fix return value in function returning voidDimitri Staessens2020-12-121-1/+1
| | | | | | | This causes builds to fail on systems where OpenSSL is not available. Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* ipcpd: Add congestion avoidance policiesDimitri Staessens2020-12-023-6/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This adds congestion avoidance policies to the unicast IPCP. The default policy is a multi-bit explicit congestion avoidance algorithm based on data-center TCP congestion avoidance (DCTCP) to relay information about the maximum queue depth that packets experienced to the receiver. There's also a "nop" policy to disable congestion avoidance for testing and benchmarking purposes. The (initial) API for congestion avoidance policies is: void * (* ctx_create)(void); void (* ctx_destroy)(void * ctx); These calls create / and or destroy a context for congestion control for a specific flow. Thread-safety of the context is the responsability of the flow allocator (operations on the ctx should be performed under a lock). ca_wnd_t (* ctx_update_snd)(void * ctx, size_t len); This is the sender call to update the context, and should be called for every packet that is sent on the flow. The len parameter in this API is the packet length, which allows calculating the bandwidth. It returns an opaque union type that is used for the call to check/wait if the congestion window is open or closed (and allowing to release locks before waiting). bool (* ctx_update_rcv)(void * ctx, size_t len, uint8_t ecn, uint16_t * ece); This is the call to update the flow congestion context on the receiver side. It should be called for every received packet. It gets the ecn value from the packet and its length, and returns the ECE (explicit congestion experienced) value to be sent to the sender in case of congestion. The boolean returned signals whether or not a congestion update needs to be sent. void (* ctx_update_ece)(void * ctx, uint16_t ece); This is the call for the sending side top update the context when it receives an ECE update from the receiver. void (* wnd_wait)(ca_wnd_t wnd); This is a (blocking) call that waits for the congestion window to clear. It should be stateless (to avoid waiting under locks). This may change later on if passing the context is needed for different algorithms. uint8_t (* calc_ecn)(int fd, size_t len); This is the call that intermediate IPCPs(routers) should use to update the ECN field on passing packets. The multi-bit ECN policy bases the value for the ECN field on the depth of the rbuff queue packets will be sent on. I created another call to grab the queue depth as fccntl is write-locking the application. We can further optimize this to avoid most locking on the rbuff. Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* lib: Reduce timerwheel CPU consumptionDimitri Staessens2020-11-252-1/+10
| | | | | | | | | | | The timerwheel is checked during IPC calls (fevent, flow_read), causing huge load on CPU consumption in IPCPs, since they have a lot of fevent() threads for QoS. The timerwheel will need further optimization), but for now I reduced the default tick time to 5 ms and added a boolean to check that the wheel is actually used. Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* lib: Don't default to lockless rbuffDimitri Staessens2020-11-221-1/+1
| | | | | | | | I mistakenly set the default to the (buggy) lockless rbuff implementation instead of the pthread one in commit 3aec660e. Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* Revert "lib: Unmount stale RIB directories"Sander Vrijders2020-11-111-10/+1
| | | | | | | | This reverts commit 978266fe4beba21292daad2d341fe5ff22e08aba. We were incorrectly unmounting the directory under normal conditions. Signed-off-by: Sander Vrijders <sander@ouroboros.rocks> Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks>
* lib: Add Rendez-Vous mechanism for flow controlDimitri Staessens2020-10-113-31/+130
| | | | | | | | | | | | | This adds the rendez-vous mechanism to handle the case where the sending window is closed and window updates get lost. If the sending window is closed, the sender side will send an RDVS every DELT_RDV time (100ms), and give up after MAX_RDV time (1 second). Upon reception of a RDVS packet, a window update is sent immediately. We can make this much more configurable later on (build options for defaults, fccntl for runtime tuning). Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* lib: Block on closed flow control windowDimitri Staessens2020-10-112-18/+129
| | | | | | | | | | | If the sending window for flow control is closed, the sending application will now block until the window opens. Beware that until the rendez-vous mechanism is implemented, shutting down a server while the client is sending (with non-timed-out blocking write) will cause the client to hang indefinitely because its window will close. Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* lib: Refactor flow_writeDimitri Staessens2020-10-111-20/+11
| | | | | | | Refactor flow_write cleanup. Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* lib: Send and receive window updatesDimitri Staessens2020-10-113-9/+38
| | | | | | | | | This adds sending and receiving window updates for flow control. I used the 8 pad bits as part of the window update field, so it's 24 bits, allowing for ~16 million packets in flight. Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* lib: Add compiler configuration for FRCPDimitri Staessens2020-10-115-93/+153
| | | | | | | | | | | | | This allows configuring some parameters for FRCP at compile time, such as default values for Delta-t and configuration of the timerwheel. The timerwheel will now reschedule when it fails to create a packet, instead of setting the flow down immediately. Some new things added are options to store packets for retransmission on the heap, and using non-blocking calls for retransmission. The defaults do not change the current behaviour. Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* lib: Fix locking for FRCTDimitri Staessens2020-09-261-2/+4
| | | | | | | | Flows should be locked when moving the timerwheel. For frcti_snd, a rdlock is enough. Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* lib: Complete retransmission logicDimitri Staessens2020-09-255-383/+667
| | | | | | | | | | | | | | | | | | | | | | | | | | | This completes the retransmission (automated repeat-request, ARQ) logic, sending (delayed) ACK messages when needed. On deallocation, flows will ACK try to retransmit any remaining unacknowledged messages (unless the FRCTFLINGER flag is turned off; this is on by default). Applications can safely shut down as soon as everything is ACK'd (i.e. the current Delta-t run is done). The activity timeout is now passed to the IPCP for it to sleep before completing deallocation (and releasing the flow_id). That should be moved to the IRMd in due time. The timerwheel is revised to be multi-level to reduce memory consumption. The resolution bumps by a factor of 1 << RXMQ_BUMP (16) and each level has RXMQ_SLOTS (1 << 8) slots. The lowest level has a resolution of (1 << RXMQ_RES) (20) ns, which is roughly a millisecond. Currently, 3 levels are defined, so the largest delay we can schedule at each level is: Level 0: 256ms Level 1: 4s Level 2: about a minute. Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
* lib: Allow pure acknowledgment packets in FRCTDimitri Staessens2020-06-063-150/+297
| | | | | | | | | | | | | | | | | | | | This adds the logic to send a pure acknowledgment packet without any data to send. This needed the event filter for the fqueue, as these non-data packets should not trigger application PKT events. The default timeout is now 10ms, until we have FRCP tuning as part of fccntl. Karn's algorithm seems to be very unstable with low (sub-ms) RTT estimates. Doubling RTO (every RTO) seems still too slow to prevent rtx storms when the measured rtt suddenly spikes several orders of magnitude. Just assuming the ACK'd packet is the last one transmitted seems to be a lot more stable. It can lead to temporary underestimation, but this is not a throughput-killer in FRCP. Changes most time units to nanoseconds for faster computation. Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks> Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>
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