Fix I-frame retransmission quirks.
Revamped the I-frame retransmission queue to better comply with Q.921: Figure B.7/Q.921 (sheet 1 of 10) and Figure B.9/Q.921 (Sheet 5 of 5). The changes prevent retransmitting I-frames when the peer is busy (RNR) (Q.921 Section 5.6.5) and eliminate an unnecessary delay sending new I-frames after an I-frame retransmission. Related to JIRA LIBPRI-60 git-svn-id: https://origsvn.digium.com/svn/libpri/branches/1.4@2200 2fbb986a-6c06-0410-b554-c9c1f0a7f128
This commit is contained in:
Richard Mudgett
parent
e01dce27b7
commit
d1cac6352a
14
pri_q921.h
14
pri_q921.h
@ -163,11 +163,17 @@ typedef union {
|
||||
struct q921_header h;
|
||||
} q921_h;
|
||||
|
||||
enum q921_tx_frame_status {
|
||||
Q921_TX_FRAME_NEVER_SENT,
|
||||
Q921_TX_FRAME_PUSHED_BACK,
|
||||
Q921_TX_FRAME_SENT,
|
||||
};
|
||||
|
||||
typedef struct q921_frame {
|
||||
struct q921_frame *next; /* Next in list */
|
||||
int len; /* Length of header + body */
|
||||
int transmitted; /* Have we been transmitted */
|
||||
q921_i h;
|
||||
struct q921_frame *next; /*!< Next in list */
|
||||
int len; /*!< Length of header + body */
|
||||
enum q921_tx_frame_status status; /*!< Tx frame status */
|
||||
q921_i h; /*!< Actual frame contents. */
|
||||
} q921_frame;
|
||||
|
||||
#define Q921_INC(j) (j) = (((j) + 1) % 128)
|
||||
|
||||
153
q921.c
153
q921.c
@ -406,7 +406,7 @@ static int q921_ack_packet(struct q921_link *link, int num)
|
||||
ctrl = link->ctrl;
|
||||
|
||||
for (prev = NULL, f = link->tx_queue; f; prev = f, f = f->next) {
|
||||
if (!f->transmitted) {
|
||||
if (f->status != Q921_TX_FRAME_SENT) {
|
||||
break;
|
||||
}
|
||||
if (f->h.n_s == num) {
|
||||
@ -421,7 +421,7 @@ static int q921_ack_packet(struct q921_link *link, int num)
|
||||
"-- ACKing N(S)=%d, tx_queue head is N(S)=%d (-1 is empty, -2 is not transmitted)\n",
|
||||
f->h.n_s,
|
||||
link->tx_queue
|
||||
? link->tx_queue->transmitted
|
||||
? link->tx_queue->status == Q921_TX_FRAME_SENT
|
||||
? link->tx_queue->h.n_s
|
||||
: -2
|
||||
: -1);
|
||||
@ -464,22 +464,6 @@ static void reschedule_t203(struct q921_link *link)
|
||||
}
|
||||
#endif
|
||||
|
||||
#if 0
|
||||
static int q921_unacked_iframes(struct q921_link *link)
|
||||
{
|
||||
struct q921_frame *f = link->tx_queue;
|
||||
int cnt = 0;
|
||||
|
||||
while (f) {
|
||||
if (f->transmitted)
|
||||
cnt++;
|
||||
f = f->next;
|
||||
}
|
||||
|
||||
return cnt;
|
||||
}
|
||||
#endif
|
||||
|
||||
static void start_t203(struct q921_link *link)
|
||||
{
|
||||
struct pri *ctrl;
|
||||
@ -642,8 +626,8 @@ static int q921_send_queued_iframes(struct q921_link *link)
|
||||
ctrl = link->ctrl;
|
||||
|
||||
for (f = link->tx_queue; f; f = f->next) {
|
||||
if (!f->transmitted) {
|
||||
/* This frame has not been sent yet. */
|
||||
if (f->status != Q921_TX_FRAME_SENT) {
|
||||
/* This frame needs to be sent. */
|
||||
break;
|
||||
}
|
||||
}
|
||||
@ -652,12 +636,20 @@ static int q921_send_queued_iframes(struct q921_link *link)
|
||||
return 0;
|
||||
}
|
||||
|
||||
if (link->peer_rx_busy
|
||||
|| (link->v_s == Q921_ADD(link->v_a, ctrl->timers[PRI_TIMER_K]))) {
|
||||
if (link->peer_rx_busy) {
|
||||
/* Don't flood debug trace if not really looking at Q.921 layer. */
|
||||
if (ctrl->debug & (/* PRI_DEBUG_Q921_STATE | */ PRI_DEBUG_Q921_DUMP)) {
|
||||
pri_message(ctrl,
|
||||
"TEI=%d Couldn't transmit I-frame at this time due to peer busy condition or window shut\n",
|
||||
"TEI=%d Couldn't transmit I-frame at this time due to peer busy condition\n",
|
||||
link->tei);
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
if (link->v_s == Q921_ADD(link->v_a, ctrl->timers[PRI_TIMER_K])) {
|
||||
/* Don't flood debug trace if not really looking at Q.921 layer. */
|
||||
if (ctrl->debug & (/* PRI_DEBUG_Q921_STATE | */ PRI_DEBUG_Q921_DUMP)) {
|
||||
pri_message(ctrl,
|
||||
"TEI=%d Couldn't transmit I-frame at this time due to window shut\n",
|
||||
link->tei);
|
||||
}
|
||||
return 0;
|
||||
@ -671,7 +663,30 @@ static int q921_send_queued_iframes(struct q921_link *link)
|
||||
}
|
||||
|
||||
/* Send it now... */
|
||||
++f->transmitted;
|
||||
switch (f->status) {
|
||||
case Q921_TX_FRAME_NEVER_SENT:
|
||||
if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
|
||||
pri_message(ctrl,
|
||||
"TEI=%d Transmitting N(S)=%d, window is open V(A)=%d K=%d\n",
|
||||
link->tei, link->v_s, link->v_a, ctrl->timers[PRI_TIMER_K]);
|
||||
}
|
||||
break;
|
||||
case Q921_TX_FRAME_PUSHED_BACK:
|
||||
if (f->h.n_s != link->v_s) {
|
||||
/* Should never happen. */
|
||||
pri_error(ctrl,
|
||||
"TEI=%d Retransmitting frame with old N(S)=%d as N(S)=%d!\n",
|
||||
link->tei, f->h.n_s, link->v_s);
|
||||
} else if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
|
||||
pri_message(ctrl, "TEI=%d Retransmitting frame N(S)=%d now!\n",
|
||||
link->tei, link->v_s);
|
||||
}
|
||||
break;
|
||||
default:
|
||||
/* Should never happen. */
|
||||
pri_error(ctrl, "Unexpected Tx Q frame status: %d", f->status);
|
||||
break;
|
||||
}
|
||||
|
||||
/*
|
||||
* Send the frame out on the assigned TEI.
|
||||
@ -684,26 +699,23 @@ static int q921_send_queued_iframes(struct q921_link *link)
|
||||
f->h.n_r = link->v_r;
|
||||
f->h.ft = 0;
|
||||
f->h.p_f = 0;
|
||||
if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
|
||||
pri_message(ctrl,
|
||||
"TEI=%d Transmitting N(S)=%d, window is open V(A)=%d K=%d\n",
|
||||
link->tei, f->h.n_s, link->v_a, ctrl->timers[PRI_TIMER_K]);
|
||||
}
|
||||
q921_transmit(ctrl, (q921_h *) (&f->h), f->len);
|
||||
Q921_INC(link->v_s);
|
||||
++frames_txd;
|
||||
|
||||
if (ctrl->debug & PRI_DEBUG_Q931_DUMP) {
|
||||
if ((ctrl->debug & PRI_DEBUG_Q931_DUMP)
|
||||
&& f->status == Q921_TX_FRAME_NEVER_SENT) {
|
||||
/*
|
||||
* The transmit operation might dump the Q.921 header, so logging
|
||||
* the Q.931 message body after the transmit puts the sections of
|
||||
* the message in the right order in the log.
|
||||
*
|
||||
* Also the dump is done here so the Q.931 part is decoded only
|
||||
* once instead of for every retransmission.
|
||||
* Also dump the Q.931 part only once instead of for every
|
||||
* retransmission.
|
||||
*/
|
||||
q931_dump(ctrl, link->tei, (q931_h *) f->h.data, f->len - 4, 1);
|
||||
}
|
||||
f->status = Q921_TX_FRAME_SENT;
|
||||
}
|
||||
|
||||
if (frames_txd) {
|
||||
@ -934,7 +946,7 @@ static struct q921_link *pri_find_tei(struct pri *ctrl, int sapi, int tei)
|
||||
/* This is the equivalent of a DL-DATA request, as well as the I-frame queued up outcome */
|
||||
int q921_transmit_iframe(struct q921_link *link, void *buf, int len, int cr)
|
||||
{
|
||||
q921_frame *f, *prev=NULL;
|
||||
struct q921_frame *f, *prev=NULL;
|
||||
struct pri *ctrl;
|
||||
|
||||
ctrl = link->ctrl;
|
||||
@ -979,7 +991,7 @@ int q921_transmit_iframe(struct q921_link *link, void *buf, int len, int cr)
|
||||
prev = f;
|
||||
}
|
||||
|
||||
f = calloc(1, sizeof(q921_frame) + len + 2);
|
||||
f = calloc(1, sizeof(struct q921_frame) + len + 2);
|
||||
if (f) {
|
||||
Q921_INIT(link, f->h);
|
||||
switch (ctrl->localtype) {
|
||||
@ -999,7 +1011,7 @@ int q921_transmit_iframe(struct q921_link *link, void *buf, int len, int cr)
|
||||
|
||||
/* Put new frame on queue tail. */
|
||||
f->next = NULL;
|
||||
f->transmitted = 0;
|
||||
f->status = Q921_TX_FRAME_NEVER_SENT;
|
||||
f->len = len + 4;
|
||||
memcpy(f->h.data, buf, len);
|
||||
if (prev)
|
||||
@ -1016,17 +1028,30 @@ int q921_transmit_iframe(struct q921_link *link, void *buf, int len, int cr)
|
||||
}
|
||||
break;
|
||||
}
|
||||
|
||||
if (link->peer_rx_busy || (link->v_s == Q921_ADD(link->v_a, ctrl->timers[PRI_TIMER_K]))) {
|
||||
if (link->peer_rx_busy) {
|
||||
if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
|
||||
pri_message(ctrl,
|
||||
"TEI=%d Just queued I-frame due to peer busy condition or window shut\n",
|
||||
"TEI=%d Just queued I-frame due to peer busy condition\n",
|
||||
link->tei);
|
||||
}
|
||||
break;
|
||||
}
|
||||
|
||||
q921_send_queued_iframes(link);
|
||||
if (!q921_send_queued_iframes(link)) {
|
||||
/*
|
||||
* No frames sent even though we just put a frame on the queue.
|
||||
*
|
||||
* Special debug message/test here because we want to say what
|
||||
* happened to the Q.931 message just queued but we don't want
|
||||
* to flood the debug trace if we are not really looking at the
|
||||
* Q.921 layer.
|
||||
*/
|
||||
if ((ctrl->debug & (PRI_DEBUG_Q921_STATE | PRI_DEBUG_Q921_DUMP))
|
||||
== PRI_DEBUG_Q921_STATE) {
|
||||
pri_message(ctrl, "TEI=%d Just queued I-frame due to window shut\n",
|
||||
link->tei);
|
||||
}
|
||||
}
|
||||
} else {
|
||||
pri_error(ctrl, "!! Out of memory for Q.921 transmit\n");
|
||||
return -1;
|
||||
@ -1073,14 +1098,13 @@ static void q921_dump_iqueue_info(struct q921_link *link)
|
||||
{
|
||||
struct pri *ctrl;
|
||||
struct q921_frame *f;
|
||||
int pending = 0, unacked = 0;
|
||||
int pending = 0;
|
||||
int unacked = 0;
|
||||
|
||||
ctrl = link->ctrl;
|
||||
|
||||
unacked = pending = 0;
|
||||
|
||||
for (f = link->tx_queue; f; f = f->next) {
|
||||
if (f->transmitted) {
|
||||
if (f->status == Q921_TX_FRAME_SENT) {
|
||||
unacked++;
|
||||
} else {
|
||||
pending++;
|
||||
@ -2217,11 +2241,11 @@ static void update_v_a(struct q921_link *link, int n_r)
|
||||
link->v_a = n_r;
|
||||
}
|
||||
|
||||
/*! \brief Is V(A) <= N(R) <= V(S) ? */
|
||||
static int n_r_is_valid(struct q921_link *link, int n_r)
|
||||
{
|
||||
int x;
|
||||
|
||||
/* Is V(A) <= N(R) <= V(S) */
|
||||
for (x = link->v_a; x != n_r && x != link->v_s; Q921_INC(x)) {
|
||||
}
|
||||
if (x != n_r) {
|
||||
@ -2346,37 +2370,27 @@ static pri_event *q921_rr_rx(struct q921_link *link, q921_h *h)
|
||||
|
||||
static int q921_invoke_retransmission(struct q921_link *link, int n_r)
|
||||
{
|
||||
int frames_txd = 0;
|
||||
int frames_supposed_to_tx = 0;
|
||||
q921_frame *f;
|
||||
unsigned int local_v_s = link->v_s;
|
||||
struct q921_frame *f;
|
||||
struct pri *ctrl;
|
||||
|
||||
ctrl = link->ctrl;
|
||||
|
||||
/* All acked frames should already have been removed from the queue. */
|
||||
for (f = link->tx_queue; f && f->transmitted; f = f->next) {
|
||||
if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
|
||||
pri_message(ctrl, "TEI=%d Retransmitting frame N(S)=%d now!\n",
|
||||
link->tei, f->h.n_s);
|
||||
/*
|
||||
* All acked frames should already have been removed from the queue.
|
||||
* Push back all sent frames.
|
||||
*/
|
||||
for (f = link->tx_queue; f && f->status == Q921_TX_FRAME_SENT; f = f->next) {
|
||||
f->status = Q921_TX_FRAME_PUSHED_BACK;
|
||||
|
||||
/* Sanity check: Is V(A) <= N(S) <= V(S)? */
|
||||
if (!n_r_is_valid(link, f->h.n_s)) {
|
||||
pri_error(ctrl,
|
||||
"Tx Q frame with invalid N(S)=%d. Must be (V(A)=%d) <= N(S) <= (V(S)=%d)\n",
|
||||
f->h.n_s, link->v_a, link->v_s);
|
||||
}
|
||||
|
||||
/* Give the other side our current N(R) */
|
||||
f->h.n_r = link->v_r;
|
||||
f->h.p_f = 0;
|
||||
q921_transmit(ctrl, (q921_h *) (&f->h), f->len);
|
||||
frames_txd++;
|
||||
}
|
||||
|
||||
while (local_v_s != n_r) {
|
||||
Q921_DEC(local_v_s);
|
||||
frames_supposed_to_tx++;
|
||||
}
|
||||
if (frames_supposed_to_tx != frames_txd) {
|
||||
pri_error(ctrl, "!!!!!!!!!!!! Should have only transmitted %d frames!\n", frames_supposed_to_tx);
|
||||
}
|
||||
|
||||
return frames_txd;
|
||||
link->v_s = n_r;
|
||||
return q921_send_queued_iframes(link);
|
||||
}
|
||||
|
||||
static pri_event *q921_rej_rx(struct q921_link *link, q921_h *h)
|
||||
@ -2494,7 +2508,6 @@ static pri_event *q921_iframe_rx(struct q921_link *link, q921_h *h, int len)
|
||||
delay_q931_receive = 0;
|
||||
/* FIXME: Verify that it's a command ... */
|
||||
if (link->own_rx_busy) {
|
||||
/* XXX: Note: There's a difference in th P/F between both states */
|
||||
/* DEVIATION: Handle own rx busy */
|
||||
} else if (h->i.n_s == link->v_r) {
|
||||
Q921_INC(link->v_r);
|
||||
|
||||
Loading…
Reference in New Issue
Block a user