packet: turn tunnel lock into spinlock

Lock is only held to update/check ints, so spin lock will be more
efficient.

Place the member of Packet in a new "persistent" area to make it
clear this is not touched by the PacketReinit logic.

Ticket: #5592.

src/decode.h

@@ -617,11 +617,6 @@ typedef struct Packet_
                            * It should always point to the lowest
                            * packet in a encapsulated packet */
 
-    /** mutex to protect access to:
-     *  - tunnel_rtv_cnt
-     *  - tunnel_tpr_cnt
-     */
-    SCMutex tunnel_mutex;
     /* ready to set verdict counter, only set in root */
     uint16_t tunnel_rtv_cnt;
     /* tunnel packet ref count */
@@ -638,6 +633,16 @@ typedef struct Packet_
 #ifdef PROFILING
     PktProfiling *profile;
 #endif
+    /* things in the packet that live beyond a reinit */
+    struct {
+        /** lock to protect access to:
+         *  - tunnel_rtv_cnt
+         *  - tunnel_tpr_cnt
+         *  - nfq_v.mark
+         *  - flags
+         */
+        SCSpinlock tunnel_lock;
+    } persistent;
 } Packet;
 
 /** highest mtu of the interfaces we monitor */
@@ -773,11 +778,13 @@ void CaptureStatsSetup(ThreadVars *tv, CaptureStats *s);
         ((p)->root ? (p)->root->tunnel_rtv_cnt++ : (p)->tunnel_rtv_cnt++);          \
     } while (0)
 
-#define TUNNEL_INCR_PKT_TPR(p) do {                                                 \
-        SCMutexLock((p)->root ? &(p)->root->tunnel_mutex : &(p)->tunnel_mutex);     \
-        ((p)->root ? (p)->root->tunnel_tpr_cnt++ : (p)->tunnel_tpr_cnt++);          \
-        SCMutexUnlock((p)->root ? &(p)->root->tunnel_mutex : &(p)->tunnel_mutex);   \
-    } while (0)
+static inline void TUNNEL_INCR_PKT_TPR(Packet *p)
+{
+    Packet *rp = p->root ? p->root : p;
+    SCSpinLock(&rp->persistent.tunnel_lock);
+    rp->tunnel_tpr_cnt++;
+    SCSpinUnlock(&rp->persistent.tunnel_lock);
+}
 
 #define TUNNEL_PKT_RTV(p) ((p)->root ? (p)->root->tunnel_rtv_cnt : (p)->tunnel_rtv_cnt)
 #define TUNNEL_PKT_TPR(p) ((p)->root ? (p)->root->tunnel_tpr_cnt : (p)->tunnel_tpr_cnt)
@@ -1093,8 +1100,8 @@ static inline void DecodeSetNoPacketInspectionFlag(Packet *p)
 static inline bool VerdictTunnelPacket(Packet *p)
 {
     bool verdict = true;
-    SCMutex *m = p->root ? &p->root->tunnel_mutex : &p->tunnel_mutex;
-    SCMutexLock(m);
+    SCSpinlock *lock = p->root ? &p->root->persistent.tunnel_lock : &p->persistent.tunnel_lock;
+    SCSpinLock(lock);
     const uint16_t outstanding = TUNNEL_PKT_TPR(p) - TUNNEL_PKT_RTV(p);
     SCLogDebug("tunnel: outstanding %u", outstanding);
 
@@ -1108,7 +1115,7 @@ static inline bool VerdictTunnelPacket(Packet *p)
     } else {
         verdict = false;
     }
-    SCMutexUnlock(m);
+    SCSpinUnlock(lock);
     return verdict;
 }
 

src/detect-mark.c

@@ -233,11 +233,11 @@ static int DetectMarkPacket(DetectEngineThreadCtx *det_ctx, Packet *p,
              * are fine. */
             if (p->flags & PKT_REBUILT_FRAGMENT) {
                 Packet *tp = p->root ? p->root : p;
-                SCMutexLock(&tp->tunnel_mutex);
+                SCSpinLock(&tp->persistent.tunnel_lock);
                 tp->nfq_v.mark = (nf_data->mark & nf_data->mask)
                     | (tp->nfq_v.mark & ~(nf_data->mask));
                 tp->flags |= PKT_MARK_MODIFIED;
-                SCMutexUnlock(&tp->tunnel_mutex);
+                SCSpinUnlock(&tp->persistent.tunnel_lock);
             }
         }
     }

src/packet.c

@@ -60,7 +60,7 @@ bool PacketCheckAction(const Packet *p, const uint8_t a)
  */
 void PacketInit(Packet *p)
 {
-    SCMutexInit(&p->tunnel_mutex, NULL);
+    SCSpinInit(&p->persistent.tunnel_lock, 0);
     p->alerts.alerts = PacketAlertCreate();
     PACKET_RESET_CHECKSUMS(p);
     p->livedev = NULL;
@@ -181,7 +181,7 @@ void PacketDestructor(Packet *p)
     }
     PacketAlertFree(p->alerts.alerts);
     PACKET_FREE_EXTDATA(p);
-    SCMutexDestroy(&p->tunnel_mutex);
+    SCSpinDestroy(&p->persistent.tunnel_lock);
     AppLayerDecoderEventsFreeEvents(&p->app_layer_events);
     PACKET_PROFILING_RESET(p);
 }

src/source-nfq.c

@@ -496,11 +496,11 @@ static int NFQBypassCallback(Packet *p)
          * work for those. Rebuilt packets from IP fragments are fine. */
         if (p->flags & PKT_REBUILT_FRAGMENT) {
             Packet *tp = p->root ? p->root : p;
-            SCMutexLock(&tp->tunnel_mutex);
+            SCSpinLock(&tp->persistent.tunnel_lock);
             tp->nfq_v.mark = (nfq_config.bypass_mark & nfq_config.bypass_mask)
                 | (tp->nfq_v.mark & ~nfq_config.bypass_mask);
             tp->flags |= PKT_MARK_MODIFIED;
-            SCMutexUnlock(&tp->tunnel_mutex);
+            SCSpinUnlock(&tp->persistent.tunnel_lock);
             return 1;
         }
         return 0;

src/tmqh-packetpool.c

@@ -365,8 +365,8 @@ void TmqhOutputPacketpool(ThreadVars *t, Packet *p)
             p,p->root ? "upper layer" : "tunnel root");
 
         /* get a lock to access root packet fields */
-        SCMutex *m = p->root ? &p->root->tunnel_mutex : &p->tunnel_mutex;
-        SCMutexLock(m);
+        SCSpinlock *lock = p->root ? &p->root->persistent.tunnel_lock : &p->persistent.tunnel_lock;
+        SCSpinLock(lock);
 
         if (IS_TUNNEL_ROOT_PKT(p)) {
             SCLogDebug("IS_TUNNEL_ROOT_PKT == TRUE");
@@ -390,7 +390,7 @@ void TmqhOutputPacketpool(ThreadVars *t, Packet *p)
                 SET_TUNNEL_PKT_VERDICTED(p);
 
                 PACKET_PROFILING_END(p);
-                SCMutexUnlock(m);
+                SCSpinUnlock(lock);
                 SCReturn;
             }
         } else {
@@ -426,7 +426,7 @@ void TmqhOutputPacketpool(ThreadVars *t, Packet *p)
                 /* fall through */
             }
         }
-        SCMutexUnlock(m);
+        SCSpinUnlock(lock);
 
         SCLogDebug("tunnel stuff done, move on (proot %d)", proot);
     }