static Flow *TcpReuseReplace(ThreadVars *tv, DecodeThreadVars *dtv,
FlowBucket *fb, Flow *old_f,
const uint32_t hash, const Packet *p)
{
/* tag flow as reused so future lookups won't find it */
old_f->flags |= FLOW_TCP_REUSED;
/* get some settings that we move over to the new flow */
FlowThreadId thread_id = old_f->thread_id;
/* since fb lock is still held this flow won't be found until we are done */
FLOWLOCK_UNLOCK(old_f);
/* Get a new flow. It will be either a locked flow or NULL */
Flow *f = FlowGetNew(tv, dtv, p);
if (f == NULL) {
return NULL;
}
/* flow is locked */
/* put at the start of the list */
f->hnext = fb->head;
fb->head->hprev = f;
fb->head = f;
/* initialize and return */
FlowInit(f, p);
f->flow_hash = hash;
f->fb = fb;
f->thread_id = thread_id;
return f;
}
/* FlowGetFlowFromHash
*
* Hash retrieval function for flows. Looks up the hash bucket containing the
* flow pointer. Then compares the packet with the found flow to see if it is
* the flow we need. If it isn't, walk the list until the right flow is found.
*
* If the flow is not found or the bucket was emtpy, a new flow is taken from
* the queue. FlowDequeue() will alloc new flows as long as we stay within our
* memcap limit.
*
* The p->flow pointer is updated to point to the flow.
*
* returns a *LOCKED* flow or NULL
*/
Flow *FlowGetFlowFromHash(const Packet *p)
{
Flow *f = NULL;
FlowHashCountInit;
/* get the key to our bucket */
uint32_t key = FlowGetKey(p);
/* get our hash bucket and lock it */
FlowBucket *fb = &flow_hash[key];
FBLOCK_LOCK(fb);
SCLogDebug("fb %p fb->head %p", fb, fb->head);
FlowHashCountIncr;
/* see if the bucket already has a flow */
if (fb->head == NULL) {
f = FlowGetNew(p);
if (f == NULL) {
FBLOCK_UNLOCK(fb);
FlowHashCountUpdate;
return NULL;
}
/* flow is locked */
fb->head = f;
fb->tail = f;
/* got one, now lock, initialize and return */
FlowInit(f, p);
f->fb = fb;
FBLOCK_UNLOCK(fb);
FlowHashCountUpdate;
return f;
}
/* ok, we have a flow in the bucket. Let's find out if it is our flow */
f = fb->head;
/* see if this is the flow we are looking for */
if (FlowCompare(f, p) == 0) {
Flow *pf = NULL; /* previous flow */
while (f) {
FlowHashCountIncr;
pf = f;
f = f->hnext;
if (f == NULL) {
f = pf->hnext = FlowGetNew(p);
if (f == NULL) {
FBLOCK_UNLOCK(fb);
FlowHashCountUpdate;
return NULL;
}
fb->tail = f;
/* flow is locked */
f->hprev = pf;
/* initialize and return */
FlowInit(f, p);
f->fb = fb;
FBLOCK_UNLOCK(fb);
FlowHashCountUpdate;
return f;
}
if (FlowCompare(f, p) != 0) {
/* we found our flow, lets put it on top of the
* hash list -- this rewards active flows */
if (f->hnext) {
f->hnext->hprev = f->hprev;
}
if (f->hprev) {
f->hprev->hnext = f->hnext;
}
if (f == fb->tail) {
fb->tail = f->hprev;
}
f->hnext = fb->head;
f->hprev = NULL;
fb->head->hprev = f;
fb->head = f;
/* found our flow, lock & return */
FLOWLOCK_WRLOCK(f);
FBLOCK_UNLOCK(fb);
FlowHashCountUpdate;
return f;
}
}
}
/* lock & return */
FLOWLOCK_WRLOCK(f);
FBLOCK_UNLOCK(fb);
FlowHashCountUpdate;
return f;
}
/** \brief Get Flow for packet
*
* Hash retrieval function for flows. Looks up the hash bucket containing the
* flow pointer. Then compares the packet with the found flow to see if it is
* the flow we need. If it isn't, walk the list until the right flow is found.
*
* If the flow is not found or the bucket was emtpy, a new flow is taken from
* the queue. FlowDequeue() will alloc new flows as long as we stay within our
* memcap limit.
*
* The p->flow pointer is updated to point to the flow.
*
* \param tv thread vars
* \param dtv decode thread vars (for flow log api thread data)
*
* \retval f *LOCKED* flow or NULL
*/
Flow *FlowGetFlowFromHash(ThreadVars *tv, DecodeThreadVars *dtv, const Packet *p, Flow **dest)
{
Flow *f = NULL;
/* get our hash bucket and lock it */
const uint32_t hash = p->flow_hash;
FlowBucket *fb = &flow_hash[hash % flow_config.hash_size];
FBLOCK_LOCK(fb);
SCLogDebug("fb %p fb->head %p", fb, fb->head);
/* see if the bucket already has a flow */
if (fb->head == NULL) {
f = FlowGetNew(tv, dtv, p);
if (f == NULL) {
FBLOCK_UNLOCK(fb);
return NULL;
}
/* flow is locked */
fb->head = f;
fb->tail = f;
/* got one, now lock, initialize and return */
FlowInit(f, p);
f->flow_hash = hash;
f->fb = fb;
FlowUpdateState(f, FLOW_STATE_NEW);
FlowReference(dest, f);
FBLOCK_UNLOCK(fb);
return f;
}
/* ok, we have a flow in the bucket. Let's find out if it is our flow */
f = fb->head;
/* see if this is the flow we are looking for */
if (FlowCompare(f, p) == 0) {
Flow *pf = NULL; /* previous flow */
while (f) {
pf = f;
f = f->hnext;
if (f == NULL) {
f = pf->hnext = FlowGetNew(tv, dtv, p);
if (f == NULL) {
FBLOCK_UNLOCK(fb);
return NULL;
}
fb->tail = f;
/* flow is locked */
f->hprev = pf;
/* initialize and return */
FlowInit(f, p);
f->flow_hash = hash;
f->fb = fb;
FlowUpdateState(f, FLOW_STATE_NEW);
FlowReference(dest, f);
FBLOCK_UNLOCK(fb);
return f;
}
if (FlowCompare(f, p) != 0) {
/* we found our flow, lets put it on top of the
* hash list -- this rewards active flows */
if (f->hnext) {
f->hnext->hprev = f->hprev;
}
if (f->hprev) {
f->hprev->hnext = f->hnext;
}
if (f == fb->tail) {
fb->tail = f->hprev;
}
f->hnext = fb->head;
f->hprev = NULL;
fb->head->hprev = f;
fb->head = f;
/* found our flow, lock & return */
FLOWLOCK_WRLOCK(f);
if (unlikely(TcpSessionPacketSsnReuse(p, f, f->protoctx) == 1)) {
f = TcpReuseReplace(tv, dtv, fb, f, hash, p);
if (f == NULL) {
FBLOCK_UNLOCK(fb);
return NULL;
}
}
FlowReference(dest, f);
FBLOCK_UNLOCK(fb);
return f;
}
}
}
/* lock & return */
FLOWLOCK_WRLOCK(f);
if (unlikely(TcpSessionPacketSsnReuse(p, f, f->protoctx) == 1)) {
f = TcpReuseReplace(tv, dtv, fb, f, hash, p);
if (f == NULL) {
FBLOCK_UNLOCK(fb);
return NULL;
}
}
FlowReference(dest, f);
FBLOCK_UNLOCK(fb);
return f;
}
