flow: modify lastts update logic

In the lastts timeval struct field in the flow the timestamp of the
last packet to update is recorded. This allows for tracking the timeout
of the flow. So far, this value was updated under the flow lock and also
read under the flow lock.

This patch moves the updating of this field to the FlowGetFlowFromHash
function, where it updated at the point where both the Flow and the
Flow Hash Row lock are held. This guarantees that the field is only
updated when both locks are held.

This makes reading the field safe when either lock is held, which is the
purpose of this patch.

The flow manager, while holding the flow hash row lock, can now safely
read the lastts value. This allows it to do the flow timeout check
without actually locking the flow.

diff --git a/src/flow-hash.c b/src/flow-hash.c
index 03e1df6b701d361ebec1d6a63ed6a73d9663c6f5..a2ce5708c96a375e44d17623e1d48d987853f092 100644 (file)
--- a/src/flow-hash.c
+++ b/src/flow-hash.c
@@ -529,6 +529,9 @@ Flow *FlowGetFlowFromHash(ThreadVars *tv, DecodeThreadVars *dtv, const Packet *p
         FlowInit(f, p);
         f->fb = fb;
 
+        /* update the last seen timestamp of this flow */
+        COPY_TIMESTAMP(&p->ts,&f->lastts);
+
         FBLOCK_UNLOCK(fb);
         FlowHashCountUpdate;
         return f;
@@ -564,6 +567,9 @@ Flow *FlowGetFlowFromHash(ThreadVars *tv, DecodeThreadVars *dtv, const Packet *p
                 FlowInit(f, p);
                 f->fb = fb;
 
+                /* update the last seen timestamp of this flow */
+                COPY_TIMESTAMP(&p->ts,&f->lastts);
+
                 FBLOCK_UNLOCK(fb);
                 FlowHashCountUpdate;
                 return f;
@@ -589,6 +595,9 @@ Flow *FlowGetFlowFromHash(ThreadVars *tv, DecodeThreadVars *dtv, const Packet *p
 
                 /* found our flow, lock & return */
                 FLOWLOCK_WRLOCK(f);
+                /* update the last seen timestamp of this flow */
+                COPY_TIMESTAMP(&p->ts,&f->lastts);
+
                 FBLOCK_UNLOCK(fb);
                 FlowHashCountUpdate;
                 return f;
@@ -598,6 +607,9 @@ Flow *FlowGetFlowFromHash(ThreadVars *tv, DecodeThreadVars *dtv, const Packet *p
 
     /* lock & return */
     FLOWLOCK_WRLOCK(f);
+    /* update the last seen timestamp of this flow */
+    COPY_TIMESTAMP(&p->ts,&f->lastts);
+
     FBLOCK_UNLOCK(fb);
     FlowHashCountUpdate;
     return f;

diff --git a/src/flow.c b/src/flow.c
index 2546e5289e8473daf4339c36dbf2df519d0f9c71..018e1fe64836851831bf747728da5f707bb793e1 100644 (file)
--- a/src/flow.c
+++ b/src/flow.c
@@ -246,9 +246,6 @@ void FlowHandlePacket(ThreadVars *tv, DecodeThreadVars *dtv, Packet *p)
     /* Point the Packet at the Flow */
     FlowReference(&p->flow, f);
 
-    /* update the last seen timestamp of this flow */
-    COPY_TIMESTAMP(&p->ts,&f->lastts);
-
     /* update flags and counters */
     if (FlowGetPacketDirection(f, p) == TOSERVER) {
         if (FlowUpdateSeenFlag(p)) {

diff --git a/src/flow.h b/src/flow.h
index 6f95401aa048a49e9c64ac3b6843f6b9cad16f91..fc1ea3d8ef4a294e0d7ebdfe9a83658e1e999357 100644 (file)
--- a/src/flow.h
+++ b/src/flow.h
@@ -337,7 +337,9 @@ typedef struct Flow_
 
     uint32_t flags;
 
-    /* time stamp of last update (last packet) */
+    /* time stamp of last update (last packet). Set/updated under the
+     * flow and flow hash row locks, safe to read under either the
+     * flow lock or flow hash row lock. */
     struct timeval lastts;
 
 #ifdef FLOWLOCK_RWLOCK