Added support for integrated Tap networking interfaces on OSX

0readme_ethernet.txt

@@ -43,9 +43,9 @@ bridge, or route TAP devices for you.
 Integrated Universal TUN/TAP support can be used for host<->simulator network
 traffic (on the platforms where it is available) by using the SIMH command:
 "attach xq tap:tapN" (i.e. attach xq tap:tap0).  Platforms that this has been
-tested on include: Linux, FreeBSD, OpenBSD, NetBSD.  Each of these platforms
+tested on include: Linux, FreeBSD, OpenBSD, NetBSD and OSX.  Each of these 
-has some way to create a tap pseudo device and then bridge it with a physical
+platforms has some way to create a tap pseudo device (and possibly then to 
-network interface.
+bridge it with a physical network interface).
 
 The following steps were performed to get a working SIMH vax simulator 
 sharing a physical NIC and allowing Host<->SIMH vax communications:
@@ -117,6 +117,29 @@ NetBSD (NetBSD 5.0.2)
 
     # Run simulator and "attach xq tap:tap0"
 
+OSX (Snow Leopard)
+    OSX Does NOT have native support for tun/tap interfaces.  It also does not have native
+    support for bridging.
+    
+    Mattias Nissler has created tun/tap functionality available at http://tuntaposx,sourceforge.net/
+    
+    We'll punt on bridging for the sake of this example and move on to use a basic tap
+    based internal network so a host and guest can communicate directly.
+    
+    Download the install package from: 
+    http://sourceforge.net/projects/tuntaposx/files/tuntap/20090913/tuntap_20090913.tar.gz
+    
+    Expand the tarball to a directory.
+    Invoke the package installer tuntap_20090913.pkg
+    Click through the various prompts accepting things and eventually installing the package.
+    
+    # Run simulator and:
+       sim> attach xq tap:tap0
+       sim> ! ifconfig tap0 192.168.6.1 netmask 255.255.255.0
+
+    Simulated system uses IP address 192.168.6.2 and host uses 192.167.6.1 and things work.
+    As far as I can tell you must run as root for this to work.
+    
 -------------------------------------------------------------------------------
 
 Windows notes:
@@ -331,14 +354,15 @@ Dave
                                Change Log
 ===============================================================================
   
-  07-Jul-11  MB   VMS Pcap (from Mike Burke)
+  29-Oct-11  MP   Added support for integrated Tap networking interfaces on OSX
-                     - Fixed Alpha issues
-                     - Added OpenVMS Integrety support
   17-Aug-11  RMS  Fix from Sergey Oboguev relating to XU and XQ Auto Config and 
                   vector assignments
   12-Aug-11  MP   Cleaned up payload length determination
                   Fixed race condition detecting reflections when threaded 
                   reading and writing is enabled
+  07-Jul-11  MB   VMS Pcap (from Mike Burke)
+                     - Fixed Alpha issues
+                     - Added OpenVMS Integrety support
   20-Apr-11  MP   Fixed save/restore behavior
   12-Jan-11  DTH  Added SHOW XU FILTERS modifier
   11-Jan-11  DTH  Corrected DEUNA/DELUA SELFTEST command, enabling use by

makefile

@@ -66,7 +66,7 @@ ifeq ($(WIN32),)
     # Provide support for Tap networking on Linux
     NETWORK_TAP_CCDEFS = -DUSE_TAP_NETWORK
   endif
-  ifeq (bsdtuntap,$(shell if $(TEST) -e /usr/include/net/if_tun.h; then echo bsdtuntap; fi))
+  ifeq (bsdtuntap,$(shell if $(TEST) -e /usr/include/net/if_tun.h -o -e /Library/Extensions/tap.kext; then echo bsdtuntap; fi))
     # Provide support for Tap networking
     NETWORK_TAP_CCDEFS = -DUSE_TAP_NETWORK -DUSE_BSDTUNTAP
   endif

sim_ether.c

@@ -787,7 +787,7 @@ void eth_show_dev (FILE* st, ETH_DEV* dev)
 #elif defined(USE_BSDTUNTAP)
 #include <sys/types.h>
 #include <net/if_types.h>
-#include <net/if_tun.h>
+#include <net/if.h>
 #else /* We don't know how to do this on the current platform */
 #undef USE_TAP_NETWORK
 #endif
@@ -1399,6 +1399,23 @@ t_stat eth_open(ETH_DEV* dev, char* name, DEVICE* dptr, uint32 dbit)
         dev->fd_handle = tun;
         strcpy(savname, savname+4);
       }
+#if defined (__APPLE__)
+      if (1) {
+        struct ifreq ifr;
+        int s;
+
+        memset (&ifr, 0, sizeof(ifr));
+        ifr.ifr_addr.sa_family = AF_INET;
+        strncpy(ifr.ifr_name, savname+4, sizeof(ifr.ifr_name));
+        if ((s = socket(AF_INET, SOCK_DGRAM, 0)) >= 0) {
+          if (ioctl(s, SIOCGIFFLAGS, (caddr_t)&ifr) >= 0) {
+            ifr.ifr_flags |= IFF_UP;
+            ioctl(s, SIOCSIFFLAGS, (caddr_t)&ifr);
+          }
+          close(s);
+        }
+      }
+#endif
     } else {
       strncpy(errbuf, strerror(errno), sizeof(errbuf)-1);
     }
@@ -1465,7 +1482,7 @@ t_stat eth_open(ETH_DEV* dev, char* name, DEVICE* dptr, uint32 dbit)
 #endif
 #endif /* !defined (USE_READER_THREAD */
 #if defined (__APPLE__)
-  if (1) {
+  if (dev->pcap_mode) {
     /* Deliver packets immediately, needed for OS X 10.6.2 and later
      * (Snow-Leopard).
      * See this thread on libpcap and Mac Os X 10.6 Snow Leopard on