From bfc29ca20406ccd69363b0f9796987534318e7ae Mon Sep 17 00:00:00 2001 From: Dimitri Staessens Date: Fri, 27 Jul 2018 00:18:20 +0200 Subject: lib: Support for rudimentary retransmission This adds rudimentary support for sending and processing acknowledgments and doing retransmission. It replaces the generic timerwheel with a specific one for retransmission. This is currently a fixed wheel allowing retransmissions to be scheduled up to about 32 seconds into the future. It currently has an 8ms resolution. This could be made configurable in the future. Failures of the flow (i.e. rtx not working) are indicated by the rxmwheel_move() function returning a fd. This is currently not yet handled (maybe just setting the state of the flow to FLOWDOWN is a better solution). The shm_rdrbuff tracks the number of users of a du_buff. One user is the full stack, each retransmission will increment the refs counter (which effectively acts as a semaphore). The refs counter is decremented when a packet is acked. The du_buff is only allowed to be removed if there is only one user left (the "stack"). When a packet is retransmitted, it is copied in the rdrbuff. This is to ensure integrity of the packet when multiple layers do retransmission and it is passed down the stack again. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders --- include/ouroboros/shm_du_buff.h | 4 ++++ include/ouroboros/timerwheel.h | 47 ----------------------------------------- 2 files changed, 4 insertions(+), 47 deletions(-) delete mode 100644 include/ouroboros/timerwheel.h (limited to 'include') diff --git a/include/ouroboros/shm_du_buff.h b/include/ouroboros/shm_du_buff.h index 31090cd3..066898df 100644 --- a/include/ouroboros/shm_du_buff.h +++ b/include/ouroboros/shm_du_buff.h @@ -49,4 +49,8 @@ uint8_t * shm_du_buff_tail_release(struct shm_du_buff * sdb, void shm_du_buff_truncate(struct shm_du_buff * sdb, size_t len); +int shm_du_buff_wait_ack(struct shm_du_buff * sdb); + +int shm_du_buff_ack(struct shm_du_buff * sdb); + #endif /* OUROBOROS_SHM_DU_BUFF_H */ diff --git a/include/ouroboros/timerwheel.h b/include/ouroboros/timerwheel.h deleted file mode 100644 index 231e8103..00000000 --- a/include/ouroboros/timerwheel.h +++ /dev/null @@ -1,47 +0,0 @@ -/* - * Ouroboros - Copyright (C) 2016 - 2018 - * - * Ring buffer for incoming SDUs - * - * Dimitri Staessens - * Sander Vrijders - * - * This library is free software; you can redistribute it and/or - * modify it under the terms of the GNU Lesser General Public License - * version 2.1 as published by the Free Software Foundation. - * - * This library is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - * Lesser General Public License for more details. - * - * You should have received a copy of the GNU Lesser General Public - * License along with this library; if not, write to the Free Software - * Foundation, Inc., http://www.fsf.org/about/contact/. - */ - -#ifndef OUROBOROS_LIB_TIMERWHEEL_H -#define OUROBOROS_LIB_TIMERWHEEL_H - -struct timerwheel; - -struct timerwheel * timerwheel_create(time_t resolution, - time_t max_delay); - -void timerwheel_destroy(struct timerwheel * tw); - -struct tw_f * timerwheel_start(struct timerwheel * tw, - void (* func)(void *), - void * arg, - time_t delay); /* ms */ - -int timerwheel_restart(struct timerwheel * tw, - struct tw_f * f, - time_t delay); /* ms */ - -void timerwheel_stop(struct timerwheel * tw, - struct tw_f * f); - -void timerwheel_move(struct timerwheel * tw); - -#endif /* OUROBOROS_LIB_TIMERWHEEL_H */ -- cgit v1.2.3