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Add tx throttling for packet radios

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avoids missing data due to lack of flow control.
This commit is contained in:
gardners 2013-08-27 20:43:56 +09:30 committed by Jeremy Lakeman
parent 2b1ec5232c
commit 0cbebedc77
5 changed files with 76 additions and 19 deletions
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3
conf_schema.h
View File

@ -260,6 +260,7 @@ ATOM(bool_t, rhizome_rx, 0, boolean,, "")
ATOM(bool_t, rhizome_ads, 0, boolean,, "")
ATOM(bool_t, rhizome_nohttptx, 0, boolean,, "")
ATOM(bool_t, rhizome_mdp_rx, 0, boolean,, "")
ATOM(bool_t, throttling, 0, boolean,, "")
ATOM(bool_t, meshms, 0, boolean,, "")
ATOM(bool_t, manifests, 0, boolean,, "")
ATOM(bool_t, vomp, 0, boolean,, "")
@ -451,6 +452,8 @@ ATOM(bool_t, debug, 0, boolean,, "If true, log details
ATOM(bool_t, point_to_point, 0, boolean,, "If true, assume there will only be two devices on this interface")
ATOM(bool_t, ctsrts, 0, boolean,, "If true, enable CTS/RTS hardware handshaking")
ATOM(int32_t, uartbps, 57600, int32_rs232baudrate,, "Speed of serial UART link speed (which may be different to serial device link speed)")
ATOM(int32_t, throttle, 0, int32_nonneg,, "Limit transmit speed of serial interface (bytes per second)")
ATOM(int32_t, burst_size, 0, int32_nonneg,, "Write no more than this many bytes at a time to a serial interface")
END_STRUCT
ARRAY(interface_list, NO_DUPLICATES)

76
overlay_interface.c
View File

@ -378,6 +378,9 @@ overlay_interface_init(const char *name, struct in_addr src_addr, struct in_addr
interface->ctsrts = ifconfig->ctsrts;
set_destination_ref(&interface->destination, NULL);
interface->destination = new_destination(interface, ifconfig->encapsulation);
interface->throttle_bytes_per_second = ifconfig->throttle;
interface->throttle_burst_write_size = ifconfig->burst_size;
/* Pick a reasonable default MTU.
This will ultimately get tuned by the bandwidth and other properties of the interface */
interface->mtu = 1200;
@ -717,27 +720,52 @@ static void interface_read_stream(struct overlay_interface *interface){
}
static void write_stream_buffer(overlay_interface *interface){
if (interface->tx_bytes_pending>0) {
time_ms_t now = gettime_ms();
int bytes_allowed=interface->tx_bytes_pending;
if (bytes_allowed>0 && interface->next_tx_allowed < now) {
// Throttle output to a prescribed bit-rate
// first, reduce the number of bytes based on the configured burst size
if (interface->throttle_burst_write_size && bytes_allowed > interface->throttle_burst_write_size)
bytes_allowed = interface->throttle_burst_write_size;
if (config.debug.packetradio)
DEBUGF("Trying to write %d bytes",bytes_allowed);
int written=write(interface->alarm.poll.fd,interface->txbuffer,
interface->tx_bytes_pending);
if (config.debug.packetradio) DEBUGF("Trying to write %d bytes",
interface->tx_bytes_pending);
bytes_allowed);
if (written>0) {
interface->tx_bytes_pending-=written;
bcopy(&interface->txbuffer[written],&interface->txbuffer[0],
interface->tx_bytes_pending);
if (config.debug.packetradio) DEBUGF("Wrote %d bytes (%d left pending)",
written,interface->tx_bytes_pending);
} else {
if (config.debug.packetradio) DEBUGF("Failed to write any data");
if (config.debug.packetradio)
DEBUGF("Wrote %d bytes (%d left pending)", written, interface->tx_bytes_pending);
// Now when are we allowed to send more?
if (interface->throttle_bytes_per_second>0) {
int delay = written*1000/interface->throttle_bytes_per_second;
if (config.debug.throttling)
DEBUGF("Throttling for %dms.",delay);
interface->next_tx_allowed = now + delay;
}
} else {
if (config.debug.packetradio)
DEBUGF("Failed to write any data");
}
}
if (interface->tx_bytes_pending>0) {
// more to write, so keep POLLOUT flag
interface->alarm.poll.events|=POLLOUT;
if (interface->tx_bytes_pending>0){
if (interface->next_tx_allowed > now){
// We can't write now, so clear POLLOUT flag
interface->alarm.poll.events&=~POLLOUT;
// set the interface alarm to trigger another write
interface->alarm.alarm = interface->next_tx_allowed;
interface->alarm.deadline = interface->alarm.alarm+10;
} else {
// more to write, so set the POLLOUT flag
interface->alarm.poll.events|=POLLOUT;
}
} else {
// nothing more to write, so clear POLLOUT flag
// Nothing to write, so clear POLLOUT flag
interface->alarm.poll.events&=~POLLOUT;
// try to empty another packet from the queue ASAP
overlay_queue_schedule_next(gettime_ms());
@ -749,14 +777,15 @@ static void write_stream_buffer(overlay_interface *interface){
static void overlay_interface_poll(struct sched_ent *alarm)
{
struct overlay_interface *interface = (overlay_interface *)alarm;
time_ms_t now = gettime_ms();
if (alarm->poll.revents==0){
alarm->alarm=-1;
time_ms_t now = gettime_ms();
if (interface->state==INTERFACE_STATE_UP
&& interface->destination->tick_ms>0
&& interface->send_broadcasts){
&& interface->send_broadcasts
&& interface->tx_bytes_pending<=0){
if (now >= interface->destination->last_tx+interface->destination->tick_ms)
overlay_send_tick_packet(interface->destination);
@ -766,15 +795,17 @@ static void overlay_interface_poll(struct sched_ent *alarm)
}
switch(interface->socket_type){
case SOCK_DGRAM:
case SOCK_STREAM:
write_stream_buffer(interface);
break;
case SOCK_DGRAM:
break;
case SOCK_FILE:
interface_read_file(interface);
now = gettime_ms();
break;
}
if (alarm->alarm!=-1 && interface->state==INTERFACE_STATE_UP) {
if (alarm->alarm < now)
alarm->alarm = now;
@ -786,6 +817,12 @@ static void overlay_interface_poll(struct sched_ent *alarm)
switch(interface->socket_type){
case SOCK_STREAM:
write_stream_buffer(interface);
if (alarm->alarm!=-1 && interface->state==INTERFACE_STATE_UP) {
if (alarm->alarm < now)
alarm->alarm = now;
unschedule(alarm);
schedule(alarm);
}
break;
case SOCK_DGRAM:
case SOCK_FILE:
@ -865,7 +902,10 @@ overlay_broadcast_ensemble(struct network_destination *destination,
interface->tx_bytes_pending=out_len;
write_stream_buffer(interface);
if (interface->alarm.alarm!=-1){
unschedule(&interface->alarm);
schedule(&interface->alarm);
}
return 0;
}

2
overlay_queue.c
View File

@ -288,6 +288,8 @@ overlay_calc_queue_time(overlay_txqueue *queue, struct overlay_frame *frame){
int i;
for(i=0;i<frame->destination_count;i++)
{
if (frame->destinations[i].destination->interface->tx_bytes_pending>0)
continue;
time_ms_t next_packet = limit_next_allowed(&frame->destinations[i].destination->transfer_limit);
if (frame->destinations[i].transmit_time){
time_ms_t delay_until = frame->destinations[i].transmit_time + frame->destinations[i].destination->resend_delay;

5
serval.h
View File

@ -443,6 +443,11 @@ typedef struct overlay_interface {
int recv_offset; /* file offset */
unsigned char txbuffer[OVERLAY_INTERFACE_RX_BUFFER_SIZE];
int tx_bytes_pending;
// Throttle TX rate if required (stream interfaces only for now)
uint32_t throttle_bytes_per_second;
uint32_t throttle_burst_write_size;
uint64_t next_tx_allowed;
struct slip_decode_state slip_decode_state;

9
tests/routing
View File

@ -232,16 +232,23 @@ setup_simulate_extender() {
set interfaces.1.file "$END2"
foreach_instance +A +B \
executeOk_servald config \
set debug.throttling on \
set debug.packetradio on \
set interfaces.1.type CATEAR \
set interfaces.1.socket_type STREAM \
set interfaces.1.encapsulation SINGLE \
set interfaces.1.point_to_point on \
set interfaces.1.packet_interval 5000
set interfaces.1.packet_interval 5000 \
set interfaces.1.burst_size 100 \
set interfaces.1.throttle 1000
foreach_instance +A +B start_routing_instance
}
test_simulate_extender() {
wait_until path_exists +A +B
wait_until path_exists +B +A
set_instance +A
executeOk_servald mdp ping --timeout=3 $SIDB 1
tfw_cat --stdout --stderr
}
teardown_simulate_extender() {
teardown