Backport 'lladdr' feature from 2.1, by Mykola S. Grechukh, gns@altlinux.org

http://git.altlinux.org/people/gns/packages/?p=openvpn.git;a=shortlog;h=refs/heads/lladdr

http://lists.altlinux.org/pipermail/devel/2009-June/171406.html

'llattr' option allows to specify the link layer address, 

i.e. MAC address, for TAP devices.

--- ./Makefile.am.orig

+++ ./Makefile.am

@@ -50,6 +50,7 @@ openvpn_SOURCES = \

 	fragment.c fragment.h \

 	gremlin.c gremlin.h \

 	helper.c helper.h \

+	lladdr.c lladdr.h \

 	init.c init.h \

 	integer.h \

         interval.c interval.h \

--- ./init.c.orig

+++ ./init.c

@@ -38,6 +38,7 @@

 #include "otime.h"

 #include "pool.h"

 #include "gremlin.h"

+#include "lladdr.h"

 #include "memdbg.h"

@@ -348,6 +349,9 @@ do_persist_tuntap (const struct options *options)

 	     "options --mktun or --rmtun should only be used together with --dev");

       tuncfg (options->dev, options->dev_type, options->dev_node,

 	      options->tun_ipv6, options->persist_mode);

+      if (options->persist_mode && options->lladdr)

+        set_lladdr(options->dev, options->lladdr, NULL);

+

       return true;

     }

 #endif

@@ -742,6 +746,10 @@ do_open_tun (struct context *c)

       open_tun (c->options.dev, c->options.dev_type, c->options.dev_node,

 		c->options.tun_ipv6, c->c1.tuntap);

+      /* set the hardware address */

+      if (c->options.lladdr)

+         set_lladdr(c->c1.tuntap->actual_name, c->options.lladdr, c->c2.es);

+

       /* do ifconfig */

       if (!c->options.ifconfig_noexec

 	  && ifconfig_order () == IFCONFIG_AFTER_TUN_OPEN)

--- ./dev/null

+++ ./lladdr.c

@@ -0,0 +1,61 @@

+/*

+ * Support routine for configuring link layer address 

+ */

+

+#include "config.h"

+#include "syshead.h"

+#include "buffer.h"

+#include "error.h"

+#include "common.h"

+#include "misc.h"

+

+const char *iproute_path = "/sbin/ip";

+

+int set_lladdr(const char *ifname, const char *lladdr,

+		const struct env_set *es)

+{

+  char command_line[256];

+  int r;

+

+  if (!ifname || !lladdr)

+    return -1;

+  

+#if defined(TARGET_LINUX)

+#ifdef CONFIG_FEATURE_IPROUTE

+  openvpn_snprintf (command_line, sizeof (command_line),

+		    "%s link set addr %s dev %s",

+		    iproute_path, lladdr, ifname);

+#else

+  openvpn_snprintf (command_line, sizeof (command_line),

+		    "%s %s hw ether %s",

+		    IFCONFIG_PATH,

+		    ifname, lladdr);

+#endif

+#elif defined(TARGET_SOLARIS)

+  openvpn_snprintf (command_line, sizeof (command_line),

+		    "%s %s ether %s",

+		    IFCONFIG_PATH,

+		    ifname, lladdr);

+#elif defined(TARGET_OPENBSD)

+  openvpn_snprintf (command_line, sizeof (command_line),

+		    "%s %s lladdr %s",

+		    IFCONFIG_PATH,

+		    ifname, lladdr);

+#elif defined(TARGET_DARWIN)

+  openvpn_snprintf (command_line, sizeof (command_line),

+		    "%s %s lladdr %s",

+		    IFCONFIG_PATH,

+		    ifname, lladdr);

+#elif defined(TARGET_FREEBSD)

+  openvpn_snprintf (command_line, sizeof (command_line),

+		    "%s %s ether %s",

+		    IFCONFIG_PATH,

+		    ifname, lladdr);

+#else

+      msg (M_WARN, "Sorry, but I don't know how to configure link layer addresses on this operating system.");

+      return -1;

+#endif

+

+  msg (M_INFO, "%s", command_line);

+  system_check (command_line, es, S_FATAL, "Linux ip addr add failed");

+}

--- /dev/null

+++ ./lladdr.h

@@ -0,0 +1,8 @@

+/*

+ * Support routine for configuring link layer address 

+ */

+

+#include "misc.h"

+

+int set_lladdr(const char *ifname, const char *lladdr,

+		const struct env_set *es);

--- ./openvpn.8.orig

+++ ./openvpn.8

@@ -798,6 +798,10 @@ to enumerate all available TAP-Win32

 adapters and will show both the network

 connections control panel name and the GUID for

 each TAP-Win32 adapter.

+.TP

+.B --lladdr address

+Specify the link layer address, more commonly known as the MAC address.

+Only applied to TAP devices.

 .\"*********************************************************

 .TP

 .B --ifconfig l rn

--- ./options.c.orig

+++ ./options.c

@@ -129,6 +129,7 @@ static const char usage_message[] =

   "                  does not begin with \"tun\" or \"tap\".\n"

   "--dev-node node : Explicitly set the device node rather than using\n"

   "                  /dev/net/tun, /dev/tun, /dev/tap, etc.\n"

+  "--lladdr hw     : Set the link layer address of the tap device.\n"

   "--tun-ipv6      : Build tun link capable of forwarding IPv6 traffic.\n"

   "--ifconfig l rn : TUN: configure device to use IP address l as a local\n"

   "                  endpoint and rn as a remote endpoint.  l & rn should be\n"

@@ -959,6 +960,7 @@ show_settings (const struct options *o)

   SHOW_STR (dev);

   SHOW_STR (dev_type);

   SHOW_STR (dev_node);

+  SHOW_STR (lladdr);

   SHOW_BOOL (tun_ipv6);

   SHOW_STR (ifconfig_local);

   SHOW_STR (ifconfig_remote_netmask);

@@ -1256,6 +1258,8 @@ options_postprocess (struct options *options, bool first_time)

    */

   if (options->inetd == INETD_NOWAIT)

     options->ifconfig_noexec = true;

+  if (options->lladdr && dev != DEV_TYPE_TAP)

+    msg (M_USAGE, "--lladdr can only be used in --dev tap mode");

   /*

    * Sanity check on TCP mode options

@@ -2802,6 +2806,17 @@ add_option (struct options *options,

       VERIFY_PERMISSION (OPT_P_GENERAL);

       options->dev_node = p[1];

     }

+  else if (streq (p[0], "lladdr") && p[1])

+    {

+      VERIFY_PERMISSION (OPT_P_UP);

+      if (mac_addr_safe (p[1])) /* MAC address only */

+       options->lladdr = p[1];

+      else

+       {

+         msg (msglevel, "lladdr parm '%s' must be a MAC address", p[1]);

+         goto err;

+       }

+    }

   else if (streq (p[0], "tun-ipv6"))

     {

       VERIFY_PERMISSION (OPT_P_UP);

--- ./options.h.orig

+++ ./options.h

@@ -123,6 +123,7 @@ struct options

   const char *dev;

   const char *dev_type;

   const char *dev_node;

+  const char *lladdr;

   const char *ifconfig_local;

   const char *ifconfig_remote_netmask;

   bool ifconfig_noexec;

--- ./socket.c.orig

+++ ./socket.c

@@ -234,6 +234,45 @@ openvpn_inet_aton (const char *dotted_quad, struct in_addr *addr)

     return OIA_HOSTNAME; /* probably a hostname */

 }

+bool

+mac_addr_safe (const char *mac_addr)

+{

+  /* verify non-NULL */

+  if (!mac_addr)

+    return false;

+

+  /* verify length is within limits */

+  if (strlen (mac_addr) > 17)

+    return false;

+

+  /* verify that all chars are either alphanumeric or ':' and that no

+     alphanumeric substring is greater than 2 chars */

+  {

+    int nnum = 0;

+    const char *p = mac_addr;

+    int c;

+

+    while ((c = *p++))

+      {

+       if ( (c >= '0' && c <= '9') || (c >= 'a' && c <= 'f') || (c >= 'A' && c <= 'F') )

+         {

+           ++nnum;

+           if (nnum > 2)

+             return false;

+         }

+       else if (c == ':')

+         {

+           nnum = 0;

+         }

+       else

+         return false;

+      }

+  }

+

+  /* error-checking is left to script invoked in lladdr.c */

+  return true;

+}

+

 static void

 update_remote (const char* host,

 	       struct sockaddr_in *addr,

--- ./socket.h.orig

+++ ./socket.h

@@ -345,6 +345,8 @@ void remote_list_randomize (struct remote_list *l);

 #define OIA_ERROR     -1

 int openvpn_inet_aton (const char *dotted_quad, struct in_addr *addr);

+bool mac_addr_safe (const char *mac_addr);

+

 socket_descriptor_t create_socket_tcp (void);

 socket_descriptor_t socket_do_accept (socket_descriptor_t sd,