/** \internal
* \brief Get a flow from the hash directly.
*
* Called in conditions where the spare queue is empty and memcap is reached.
*
* Walks the hash until a flow can be freed. Timeouts are disregarded, use_cnt
* is adhered to. "flow_prune_idx" atomic int makes sure we don't start at the
* top each time since that would clear the top of the hash leading to longer
* and longer search times under high pressure (observed).
*
* \retval f flow or NULL
*/
static Flow *FlowGetUsedFlow(void)
{
uint32_t idx = SC_ATOMIC_GET(flow_prune_idx) % flow_config.hash_size;
uint32_t cnt = flow_config.hash_size;
while (cnt--) {
if (++idx >= flow_config.hash_size)
idx = 0;
FlowBucket *fb = &flow_hash[idx];
if (FBLOCK_TRYLOCK(fb) != 0)
continue;
Flow *f = fb->tail;
if (f == NULL) {
FBLOCK_UNLOCK(fb);
continue;
}
if (FLOWLOCK_TRYWRLOCK(f) != 0) {
FBLOCK_UNLOCK(fb);
continue;
}
/** never prune a flow that is used by a packet or stream msg
* we are currently processing in one of the threads */
if (SC_ATOMIC_GET(f->use_cnt) > 0) {
FBLOCK_UNLOCK(fb);
FLOWLOCK_UNLOCK(f);
continue;
}
/* remove from the hash */
if (f->hprev != NULL)
f->hprev->hnext = f->hnext;
if (f->hnext != NULL)
f->hnext->hprev = f->hprev;
if (fb->head == f)
fb->head = f->hnext;
if (fb->tail == f)
fb->tail = f->hprev;
f->hnext = NULL;
f->hprev = NULL;
f->fb = NULL;
FBLOCK_UNLOCK(fb);
FlowClearMemory(f, f->protomap);
FLOWLOCK_UNLOCK(f);
(void) SC_ATOMIC_ADD(flow_prune_idx, (flow_config.hash_size - cnt));
return f;
}
return NULL;
}
/** \internal
* \brief Get a flow from the hash directly.
*
* Called in conditions where the spare queue is empty and memcap is reached.
*
* Walks the hash until a flow can be freed. Timeouts are disregarded, use_cnt
* is adhered to. "flow_prune_idx" atomic int makes sure we don't start at the
* top each time since that would clear the top of the hash leading to longer
* and longer search times under high pressure (observed).
*
* \param tv thread vars
* \param dtv decode thread vars (for flow log api thread data)
*
* \retval f flow or NULL
*/
static Flow *FlowGetUsedFlow(ThreadVars *tv, DecodeThreadVars *dtv)
{
uint32_t idx = SC_ATOMIC_GET(flow_prune_idx) % flow_config.hash_size;
uint32_t cnt = flow_config.hash_size;
while (cnt--) {
if (++idx >= flow_config.hash_size)
idx = 0;
FlowBucket *fb = &flow_hash[idx];
if (FBLOCK_TRYLOCK(fb) != 0)
continue;
Flow *f = fb->tail;
if (f == NULL) {
FBLOCK_UNLOCK(fb);
continue;
}
if (FLOWLOCK_TRYWRLOCK(f) != 0) {
FBLOCK_UNLOCK(fb);
continue;
}
/** never prune a flow that is used by a packet or stream msg
* we are currently processing in one of the threads */
if (SC_ATOMIC_GET(f->use_cnt) > 0) {
FBLOCK_UNLOCK(fb);
FLOWLOCK_UNLOCK(f);
continue;
}
/* remove from the hash */
if (f->hprev != NULL)
f->hprev->hnext = f->hnext;
if (f->hnext != NULL)
f->hnext->hprev = f->hprev;
if (fb->head == f)
fb->head = f->hnext;
if (fb->tail == f)
fb->tail = f->hprev;
f->hnext = NULL;
f->hprev = NULL;
f->fb = NULL;
SC_ATOMIC_SET(fb->next_ts, 0);
FBLOCK_UNLOCK(fb);
int state = SC_ATOMIC_GET(f->flow_state);
if (state == FLOW_STATE_NEW)
f->flow_end_flags |= FLOW_END_FLAG_STATE_NEW;
else if (state == FLOW_STATE_ESTABLISHED)
f->flow_end_flags |= FLOW_END_FLAG_STATE_ESTABLISHED;
else if (state == FLOW_STATE_CLOSED)
f->flow_end_flags |= FLOW_END_FLAG_STATE_CLOSED;
else if (state == FLOW_STATE_CAPTURE_BYPASSED)
f->flow_end_flags |= FLOW_END_FLAG_STATE_BYPASSED;
else if (state == FLOW_STATE_LOCAL_BYPASSED)
f->flow_end_flags |= FLOW_END_FLAG_STATE_BYPASSED;
f->flow_end_flags |= FLOW_END_FLAG_FORCED;
if (SC_ATOMIC_GET(flow_flags) & FLOW_EMERGENCY)
f->flow_end_flags |= FLOW_END_FLAG_EMERGENCY;
/* invoke flow log api */
if (dtv && dtv->output_flow_thread_data)
(void)OutputFlowLog(tv, dtv->output_flow_thread_data, f);
FlowClearMemory(f, f->protomap);
FlowUpdateState(f, FLOW_STATE_NEW);
FLOWLOCK_UNLOCK(f);
(void) SC_ATOMIC_ADD(flow_prune_idx, (flow_config.hash_size - cnt));
return f;
}
return NULL;
}
