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authorDimitri Staessens <dimitri.staessens@ugent.be>2018-07-27 00:18:20 +0200
committerSander Vrijders <sander.vrijders@ugent.be>2018-07-27 08:53:17 +0200
commitbfc29ca20406ccd69363b0f9796987534318e7ae (patch)
treeac41f39e11cfe989daa10277f14a9597bb5cc3b8 /src/lib/dev.c
parent1c7dcc2d37dc5a41379ca08b523bda58a51f11de (diff)
downloadouroboros-bfc29ca20406ccd69363b0f9796987534318e7ae.tar.gz
ouroboros-bfc29ca20406ccd69363b0f9796987534318e7ae.zip
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 <dimitri.staessens@ugent.be> Signed-off-by: Sander Vrijders <sander.vrijders@ugent.be>
Diffstat (limited to 'src/lib/dev.c')
-rw-r--r--src/lib/dev.c15
1 files changed, 7 insertions, 8 deletions
diff --git a/src/lib/dev.c b/src/lib/dev.c
index dd908f78..e69fec26 100644
--- a/src/lib/dev.c
+++ b/src/lib/dev.c
@@ -40,7 +40,6 @@
#include <ouroboros/utils.h>
#include <ouroboros/fqueue.h>
#include <ouroboros/qoscube.h>
-#include <ouroboros/timerwheel.h>
#include <stdlib.h>
#include <string.h>
@@ -83,6 +82,9 @@ struct port {
pthread_cond_t state_cond;
};
+#define frcti_to_flow(frcti) \
+ ((struct flow *)((uint8_t *) frcti - offsetof(struct flow, frcti)))
+
struct flow {
struct shm_rbuff * rx_rb;
struct shm_rbuff * tx_rb;
@@ -396,12 +398,12 @@ static void init(int argc,
if (pthread_rwlock_init(&ai.lock, NULL))
goto fail_lock;
- if (frct_init())
- goto fail_frct;
+ if (rxmwheel_init())
+ goto fail_rxmwheel;
return;
- fail_frct:
+ fail_rxmwheel:
pthread_rwlock_destroy(&ai.lock);
fail_lock:
for (i = 0; i < SYS_MAX_FLOWS; ++i)
@@ -437,7 +439,7 @@ static void fini(void)
if (ai.fds == NULL)
return;
- frct_fini();
+ rxmwheel_fini();
if (ai.prog != NULL)
free(ai.prog);
@@ -463,9 +465,6 @@ static void fini(void)
shm_rdrbuff_close(ai.rdrb);
- if (ai.tw != NULL)
- timerwheel_destroy(ai.tw);
-
free(ai.flows);
free(ai.ports);