Modules/IPStack - Fixed UDP port collision detection

diff --git a/KernelLand/Modules/IPStack/udp.c b/KernelLand/Modules/IPStack/udp.c
index 40e6474..ccd32bc 100644 (file)
--- a/KernelLand/Modules/IPStack/udp.c
+++ b/KernelLand/Modules/IPStack/udp.c
@@ -1,7 +1,11 @@
 /*
  * Acess2 IP Stack
- * - UDP Handling
+ * - By John Hodge (thePowersGang)
+ *
+ * udp.c
+ * - UDP Protocol handling
  */
+#define DEBUG  1
 #include "ipstack.h"
 #include <api_drv_common.h>
 #include "udp.h"
@@ -20,8 +24,8 @@ size_t        UDP_Channel_Write(tVFS_Node *Node, off_t Offset, size_t Length, const voi
  int   UDP_Channel_IOCtl(tVFS_Node *Node, int ID, void *Data);
 void   UDP_Channel_Close(tVFS_Node *Node);
 // --- Helpers
-Uint16 UDP_int_AllocatePort();
- int   UDP_int_MarkPortAsUsed(Uint16 Port);
+Uint16 UDP_int_AllocatePort(tUDPChannel *Channel);
+ int   UDP_int_ClaimPort(tUDPChannel *Channel, Uint16 Port);
 void   UDP_int_FreePort(Uint16 Port);
 
 // === GLOBALS ===
@@ -62,9 +66,7 @@ int UDP_int_ScanList(tUDPChannel *List, tInterface *Interface, void *Address, in
        tUDPPacket      *pack;
         int    len;
        
-       for(chan = List;
-               chan;
-               chan = chan->Next)
+       for(chan = List; chan; chan = chan->Next)
        {
                // Match local endpoint
                if(chan->Interface && chan->Interface != Interface)     continue;
@@ -295,36 +297,31 @@ int UDP_Channel_IOCtl(tVFS_Node *Node, int ID, void *Data)
        {
        BASE_IOCTLS(DRV_TYPE_MISC, "UDP Channel", 0x100, casIOCtls_Channel);
        
-       case 4: // getset_localport (returns bool success)
+       case 4: { // getset_localport (returns bool success)
                if(!Data)       LEAVE_RET('i', chan->LocalPort);
                if(!CheckMem( Data, sizeof(Uint16) ) ) {
                        LOG("Invalid pointer %p", Data);
                        LEAVE_RET('i', -1);
                }
                // Set port
-               chan->LocalPort = *(Uint16*)Data;
+               int req_port = *(Uint16*)Data;
                // Permissions check (Ports lower than 1024 are root-only)
-               if(chan->LocalPort != 0 && chan->LocalPort < 1024) {
+               if(req_port != 0 && req_port < 1024) {
                        if( Threads_GetUID() != 0 ) {
-                               LOG("Attempt by non-superuser to listen on port %i", chan->LocalPort);
-                               chan->LocalPort = 0;
+                               LOG("Attempt by non-superuser to listen on port %i", req_port);
                                LEAVE_RET('i', -1);
                        }
                }
                // Allocate a random port if requested
-               if( chan->LocalPort == 0 )
-                       chan->LocalPort = UDP_int_AllocatePort();
-               else
-               {
-                       // Else, mark the requested port as used
-                       if( UDP_int_MarkPortAsUsed(chan->LocalPort) == 0 ) {
-                               LOG("Port %i us currently in use", chan->LocalPort);
-                               chan->LocalPort = 0;
-                               LEAVE_RET('i', 0);
-                       }
-                       LEAVE_RET('i', 1);
+               if( req_port == 0 )
+                       UDP_int_AllocatePort(chan);
+               // Else, mark the requested port as used
+               else if( UDP_int_ClaimPort(chan, req_port) ) {
+                       LOG("Port %i is currently in use", req_port);
+                       LEAVE_RET('i', 0);
+               }
+               LEAVE_RET('i', chan->LocalPort);
                }
-               LEAVE_RET('i', 1);
        
        case 5: // getset_remoteport (returns bool success)
                if(!Data)       LEAVE_RET('i', chan->Remote.Port);
@@ -333,7 +330,8 @@ int UDP_Channel_IOCtl(tVFS_Node *Node, int ID, void *Data)
                        LEAVE_RET('i', -1);
                }
                chan->Remote.Port = *(Uint16*)Data;
-               return 1;
+               LEAVE('i', chan->Remote.Port);
+               return chan->Remote.Port;
        
        case 6: // getset_remotemask (returns bool success)
                if(!Data)       LEAVE_RET('i', chan->RemoteMask);
@@ -345,7 +343,8 @@ int UDP_Channel_IOCtl(tVFS_Node *Node, int ID, void *Data)
                if( *(int*)Data > IPStack_GetAddressSize(chan->Interface->Type) )
                        LEAVE_RET('i', -1);
                chan->RemoteMask = *(int*)Data;
-               return 1;       
+               LEAVE('i', chan->RemoteMask);
+               return chan->RemoteMask;        
 
        case 7: // set_remoteaddr (returns bool success)
                if( !chan->Interface ) {
@@ -357,6 +356,7 @@ int UDP_Channel_IOCtl(tVFS_Node *Node, int ID, void *Data)
                        LEAVE_RET('i', -1);
                }
                memcpy(&chan->Remote.Addr, Data, IPStack_GetAddressSize(chan->Interface->Type));
+               LEAVE('i', 0);
                return 0;
        }
        LEAVE_RET('i', 0);
@@ -404,37 +404,56 @@ void UDP_Channel_Close(tVFS_Node *Node)
 /**
  * \return Port Number on success, or zero on failure
  */
-Uint16 UDP_int_AllocatePort()
+Uint16 UDP_int_AllocatePort(tUDPChannel *Channel)
 {
-        int    i;
        Mutex_Acquire(&glUDP_Ports);
+        int    i;
        // Fast Search
-       for( i = UDP_ALLOC_BASE; i < 0x10000; i += 32 )
-               if( gUDP_Ports[i/32] != 0xFFFFFFFF )
-                       break;
-       if(i == 0x10000)        return 0;
-       for( ;; i++ )
+       for( int base = UDP_ALLOC_BASE; base < 0x10000; base += 32 )
        {
-               if( !(gUDP_Ports[i/32] & (1 << (i%32))) )
-                       return i;
+               if( gUDP_Ports[base/32] == 0xFFFFFFFF )
+                       continue ;
+               for( int i = 0; i < 32; i++ )
+               {
+                       if( gUDP_Ports[base/32] & (1 << i) )
+                               continue ;
+                       gUDP_Ports[base/32] |= (1 << i);
+                       Mutex_Release(&glUDP_Ports);
+                       // If claim succeeds, good
+                       if( UDP_int_ClaimPort(Channel, base + i) == 0 )
+                               return base + i;
+                       // otherwise keep looking
+                       Mutex_Acquire(&glUDP_Ports);
+                       break;
+               }
        }
        Mutex_Release(&glUDP_Ports);
+       return 0;
 }
 
 /**
  * \brief Allocate a specific port
  * \return Boolean Success
  */
-int UDP_int_MarkPortAsUsed(Uint16 Port)
+int UDP_int_ClaimPort(tUDPChannel *Channel, Uint16 Port)
 {
-       Mutex_Acquire(&glUDP_Ports);
-       if( gUDP_Ports[Port/32] & (1 << (Port%32)) ) {
-               return 0;
-               Mutex_Release(&glUDP_Ports);
+       // Search channel list for a connection with same (or wildcard)
+       // interface, and same port
+       Mutex_Acquire(&glUDP_Channels);
+       for( tUDPChannel *ch = gpUDP_Channels; ch; ch = ch->Next)
+       {
+               if( ch == Channel )
+                       continue ;
+               if( ch->Interface && ch->Interface != Channel->Interface )
+                       continue ;
+               if( ch->LocalPort != Port )
+                       continue ;
+               Mutex_Release(&glUDP_Channels);
+               return 1;
        }
-       gUDP_Ports[Port/32] |= 1 << (Port%32);
-       Mutex_Release(&glUDP_Ports);
-       return 1;
+       Channel->LocalPort = Port;
+       Mutex_Release(&glUDP_Channels);
+       return 0;
 }
 
 /**