Optimistically revert mutex that was needed with WinPcap. Npcap likel…

…y is unaffected.
safebaseline · Oct 3, 2018 · 30db709 · 30db709
1 parent 5a505b9
commit 30db709
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Showing 6 changed files with 4 additions and 53 deletions.
diff --git a/libdnet-stripped/NMAP_MODIFICATIONS b/libdnet-stripped/NMAP_MODIFICATIONS
@@ -2174,7 +2174,7 @@ index 3c09f9c..77225b6 100644
  	/* Loop through all the pcap devices until we find a match. */
  	selected = NULL;
 
-o Use a mutex on Windows to avoid a hang when accessing WinPCAP driver.
+o (LATER REVERTED) Use a mutex on Windows to avoid a hang when accessing WinPCAP driver.
   Reported by multiple users on Windows 8.1 and Windows Server 2012 R2.
   Seems to hang when the WinPCAP driver is accessed via OpenServiceA by
   multiple processes at once. Users report that this change, which uses a
@@ -2408,3 +2408,6 @@ index 434142e..31b9f8c 100644
  		    ipbuf, &type, &flags, macbuf, maskbuf, devbuf);
 
  		if (i < 4 || (flags & ATF_COM) == 0)
+
+o REVERTED the change that added a mutex protecting calls to OpenServiceA. We
+  are optimistic that Npcap does not have the reported problem.
diff --git a/libdnet-stripped/src/eth-win32.c b/libdnet-stripped/src/eth-win32.c
@@ -57,21 +57,13 @@ eth_open(const char *device)
 {
 	eth_t *eth;
 	char pcapdev[128];
-  HANDLE pcapMutex;
-  DWORD wait;
 
 	if (eth_get_pcap_devname(device, pcapdev, sizeof(pcapdev)) != 0)
 		return (NULL);
 
 	if ((eth = calloc(1, sizeof(*eth))) == NULL)
 		return (NULL);
-  pcapMutex = CreateMutex(NULL, 0, "Global\\DnetPcapHangAvoidanceMutex");
-  wait = WaitForSingleObject(pcapMutex, INFINITE);
 	eth->lpa = PacketOpenAdapter(pcapdev);
-  if (wait == WAIT_ABANDONED || wait == WAIT_OBJECT_0) {
-    ReleaseMutex(pcapMutex);
-  }
-  CloseHandle(pcapMutex);
 	if (eth->lpa == NULL) {
 		eth_close(eth);
 		return (NULL);
@@ -120,21 +112,11 @@ eth_send(eth_t *eth, const void *buf, size_t len)
 eth_t *
 eth_close(eth_t *eth)
 {
-  HANDLE pcapMutex;
-  DWORD wait;
 	if (eth != NULL) {
 		if (eth->pkt != NULL)
 			PacketFreePacket(eth->pkt);
 		if (eth->lpa != NULL)
-    {
-      pcapMutex = CreateMutex(NULL, 0, "Global\\DnetPcapHangAvoidanceMutex");
-      wait = WaitForSingleObject(pcapMutex, INFINITE);
 			PacketCloseAdapter(eth->lpa);
-      if (wait == WAIT_ABANDONED || wait == WAIT_OBJECT_0) {
-        ReleaseMutex(pcapMutex);
-      }
-      CloseHandle(pcapMutex);
-    }
 		free(eth);
 	}
 	return (NULL);

diff --git a/libdnet-stripped/src/intf-win32.c b/libdnet-stripped/src/intf-win32.c
@@ -521,8 +521,6 @@ intf_get_pcap_devname_cached(const char *intf_name, char *pcapdev, int pcapdevle
 	pcap_if_t *pdev;
 	intf_t *intf;
 	char errbuf[PCAP_ERRBUF_SIZE];
-	HANDLE pcapMutex;
-	DWORD wait;
 
 	if ((intf = intf_open()) == NULL)
 		return (-1);
@@ -543,20 +541,10 @@ intf_get_pcap_devname_cached(const char *intf_name, char *pcapdev, int pcapdevle
   }
 
   if (pcapdevs == NULL) {
-    pcapMutex = CreateMutex(NULL, 0, "Global\\DnetPcapHangAvoidanceMutex");
-    wait = WaitForSingleObject(pcapMutex, INFINITE);
     if (pcap_findalldevs(&pcapdevs, errbuf) == -1) {
-      if (wait == WAIT_ABANDONED || wait == WAIT_OBJECT_0) {
-        ReleaseMutex(pcapMutex);
-      }
-      CloseHandle(pcapMutex);
       intf_close(intf);
       return (-1);
     }
-    if (wait == WAIT_ABANDONED || wait == WAIT_OBJECT_0) {
-      ReleaseMutex(pcapMutex);
-    }
-    CloseHandle(pcapMutex);
   }
 
 	/* Loop through all the pcap devices until we find a match. */

diff --git a/libnetutil/netutil.cc b/libnetutil/netutil.cc
@@ -4094,8 +4094,6 @@ pcap_t *my_pcap_open_live(const char *device, int snaplen, int promisc, int to_m
        with what we have then ... */
     Strncpy(pcapdev, device, sizeof(pcapdev));
   }
-  HANDLE pcapMutex = CreateMutex(NULL, 0, TEXT("Global\\DnetPcapHangAvoidanceMutex"));
-  DWORD wait = WaitForSingleObject(pcapMutex, INFINITE);
 #else
   Strncpy(pcapdev, device, sizeof(pcapdev));
 #endif
@@ -4145,10 +4143,6 @@ pcap_t *my_pcap_open_live(const char *device, int snaplen, int promisc, int to_m
 #endif /* not __amigaos__ */
 
 #ifdef WIN32
-  if (wait == WAIT_ABANDONED || wait == WAIT_OBJECT_0) {
-    ReleaseMutex(pcapMutex);
-  }
-  CloseHandle(pcapMutex);
   /* We want any responses back ASAP */
   /* This is unnecessary with Npcap since libpcap calls PacketSetMinToCopy(0)
    * based on immediate mode. Have not determined if it is needed for WinPcap

diff --git a/mswin32/winfix.cc b/mswin32/winfix.cc
@@ -315,8 +315,6 @@ void win_init()
 	__try
 #endif
 	{
-    HANDLE pcapMutex;
-    DWORD wait;
 		ULONG len = sizeof(pcaplist);
 
 		o.have_pcap = true;
@@ -342,13 +340,7 @@ void win_init()
 		if (pcap_driver == PCAP_DRIVER_NPCAP)
 			init_npcap_dll_path();
 
-    pcapMutex = CreateMutex(NULL, 0, "Global\\DnetPcapHangAvoidanceMutex");
-    wait = WaitForSingleObject(pcapMutex, INFINITE);
 		PacketGetAdapterNames(pcaplist, &len);
-    if (wait == WAIT_ABANDONED || wait == WAIT_OBJECT_0) {
-      ReleaseMutex(pcapMutex);
-    }
-    CloseHandle(pcapMutex);
 
 #ifdef _MSC_VER
 		if(FAILED(__HrLoadAllImportsForDll("wpcap.dll")))

diff --git a/nping/winfix.cc b/nping/winfix.cc
@@ -315,8 +315,6 @@ void win_init()
 	__try
 #endif
 	{
-    HANDLE pcapMutex;
-    DWORD wait;
 		ULONG len = sizeof(pcaplist);
 
     if(o.getDebugging() >= DBG_2) printf("Trying to initialize Windows pcap engine\n");
@@ -341,13 +339,7 @@ void win_init()
     if (pcap_driver == PCAP_DRIVER_NPCAP)
       init_npcap_dll_path();
 
-    pcapMutex = CreateMutex(NULL, 0, "Global\\DnetPcapHangAvoidanceMutex");
-    wait = WaitForSingleObject(pcapMutex, INFINITE);
 		PacketGetAdapterNames(pcaplist, &len);
-    if (wait == WAIT_ABANDONED || wait == WAIT_OBJECT_0) {
-      ReleaseMutex(pcapMutex);
-    }
-    CloseHandle(pcapMutex);
 
 #ifdef _MSC_VER
 		if(FAILED(__HrLoadAllImportsForDll("wpcap.dll")))