datapath-windows: Implement locking in conntrack NAT.

This patch primarily replaces existing ndis RWlock based implementaion
for NAT in conntrack with a spinlock based implementation inside NAT,
module along with some conntrack optimization.

- The 'ovsNatTable' and 'ovsUnNatTable' tables are shared
  between cleanup threads and packet processing thread.
  In order to protect these two tables use a spinlock.
  Also introduce counters to track number of nat entries.
- Introduce a new function OvsGetTcpHeader() to retrieve TCP header
  and payload length, to optimize for TCP traffic.
- Optimize conntrack look up.
- Remove 'bucketlockRef' member from conntrack entry structure.

Testing:
Verified loading/unloading the driver with driver verified enabled.
Ran TCP/UDP and ICMP traffic.

Signed-off-by: Anand Kumar <kumaranand@vmware.com>
Acked-by: Alin Gabriel Serdean <aserdean@ovn.org>
Signed-off-by: Alin Gabriel Serdean <aserdean@ovn.org>

1 files changed, 22 insertions, 14 deletions

diff --git a/datapath-windows/ovsext/Conntrack.h b/datapath-windows/ovsext/Conntrack.h
index 7dc92a19c..7a80eea73 100644
--- a/datapath-windows/ovsext/Conntrack.h
+++ b/datapath-windows/ovsext/Conntrack.h
@@ -99,8 +99,6 @@ typedef struct _NAT_ACTION_INFO {
 } NAT_ACTION_INFO, *PNAT_ACTION_INFO;
 
 typedef struct OVS_CT_ENTRY {
-    /* Reference to ovsCtBucketLock of ovsConntrackTable.*/
-    PNDIS_RW_LOCK_EX bucketLockRef;
     NDIS_SPIN_LOCK lock;       /* Protects OVS_CT_ENTRY. */
     OVS_CT_KEY  key;
     OVS_CT_KEY  rev_key;
@@ -156,23 +154,33 @@ OvsConntrackUpdateExpiration(OVS_CT_ENTRY *ctEntry,
     ctEntry->expiration = now + interval;
 }
 
-static __inline UINT32
-OvsGetTcpPayloadLength(PNET_BUFFER_LIST nbl)
+static const TCPHdr*
+OvsGetTcpHeader(PNET_BUFFER_LIST nbl,
+                OVS_PACKET_HDR_INFO *layers,
+                VOID *storage,
+                UINT32 *tcpPayloadLen)
 {
     IPHdr *ipHdr;
     TCPHdr *tcp;
-    char *ipBuf[sizeof(EthHdr) + sizeof(IPHdr) + sizeof(TCPHdr)];
+    VOID *dest = storage;
 
-    ipHdr = NdisGetDataBuffer(NET_BUFFER_LIST_FIRST_NB(nbl), sizeof *ipBuf,
-                              (PVOID)&ipBuf, 1 /*no align*/, 0);
+    ipHdr = NdisGetDataBuffer(NET_BUFFER_LIST_FIRST_NB(nbl),
+                              layers->l4Offset + sizeof(TCPHdr),
+                              NULL, 1 /*no align*/, 0);
     if (ipHdr == NULL) {
-        return 0;
+        return NULL;
     }
 
-    ipHdr = (IPHdr *)((PCHAR)ipHdr + sizeof(EthHdr));
+    ipHdr = (IPHdr *)((PCHAR)ipHdr + layers->l3Offset);
     tcp = (TCPHdr *)((PCHAR)ipHdr + ipHdr->ihl * 4);
+    if (tcp->doff * 4 >= sizeof *tcp) {
+        NdisMoveMemory(dest, tcp, sizeof(TCPHdr));
+        *tcpPayloadLen = ntohs((ipHdr->tot_len) - (ipHdr->ihl * 4) -
+                               (TCP_HDR_LEN(tcp)));
+        return storage;
+    }
 
-    return (ntohs(ipHdr->tot_len) - (ipHdr->ihl * 4) - (TCP_HDR_LEN(tcp)));
+    return NULL;
 }
 
 VOID OvsCleanupConntrack(VOID);
@@ -184,17 +192,17 @@ NDIS_STATUS OvsExecuteConntrackAction(OvsForwardingContext *fwdCtx,
 BOOLEAN OvsConntrackValidateTcpPacket(const TCPHdr *tcp);
 BOOLEAN OvsConntrackValidateIcmpPacket(const ICMPHdr *icmp);
 OVS_CT_ENTRY * OvsConntrackCreateTcpEntry(const TCPHdr *tcp,
-                                          PNET_BUFFER_LIST nbl,
-                                          UINT64 now);
+                                          UINT64 now,
+                                          UINT32 tcpPayloadLen);
 NDIS_STATUS OvsCtMapTcpProtoInfoToNl(PNL_BUFFER nlBuf,
                                      OVS_CT_ENTRY *conn_);
 OVS_CT_ENTRY * OvsConntrackCreateOtherEntry(UINT64 now);
 OVS_CT_ENTRY * OvsConntrackCreateIcmpEntry(UINT64 now);
 enum CT_UPDATE_RES OvsConntrackUpdateTcpEntry(OVS_CT_ENTRY* conn_,
                                               const TCPHdr *tcp,
-                                              PNET_BUFFER_LIST nbl,
                                               BOOLEAN reply,
-                                              UINT64 now);
+                                              UINT64 now,
+                                              UINT32 tcpPayloadLen);
 enum CT_UPDATE_RES OvsConntrackUpdateOtherEntry(OVS_CT_ENTRY *conn_,
                                                 BOOLEAN reply,
                                                 UINT64 now);