Imported Upstream version 2.2.1upstream/2.2.1

1 files changed, 290 insertions, 0 deletions

diff --git a/mtu.c b/mtu.c
new file mode 100644
index 0000000..494f939
--- /dev/null
+++ b/mtu.c
@@ -0,0 +1,290 @@
+/*
+ *  OpenVPN -- An application to securely tunnel IP networks
+ *             over a single TCP/UDP port, with support for SSL/TLS-based
+ *             session authentication and key exchange,
+ *             packet encryption, packet authentication, and
+ *             packet compression.
+ *
+ *  Copyright (C) 2002-2010 OpenVPN Technologies, Inc. <sales@openvpn.net>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2
+ *  as published by the Free Software Foundation.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program (see the file COPYING included with this
+ *  distribution); if not, write to the Free Software Foundation, Inc.,
+ *  59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include "syshead.h"
+
+#include "common.h"
+#include "buffer.h"
+#include "error.h"
+#include "integer.h"
+#include "mtu.h"
+
+#include "memdbg.h"
+
+/* allocate a buffer for socket or tun layer */
+void
+alloc_buf_sock_tun (struct buffer *buf,
+		    const struct frame *frame,
+		    const bool tuntap_buffer,
+		    const unsigned int align_mask)
+{
+  /* allocate buffer for overlapped I/O */
+  *buf = alloc_buf (BUF_SIZE (frame));
+  ASSERT (buf_init (buf, FRAME_HEADROOM_ADJ (frame, align_mask)));
+  buf->len = tuntap_buffer ? MAX_RW_SIZE_TUN (frame) : MAX_RW_SIZE_LINK (frame);
+  ASSERT (buf_safe (buf, 0));
+}
+
+void
+frame_finalize (struct frame *frame,
+		bool link_mtu_defined,
+		int link_mtu,
+		bool tun_mtu_defined,
+		int tun_mtu)
+{
+  /* Set link_mtu based on command line options */
+  if (tun_mtu_defined)
+    {
+      ASSERT (!link_mtu_defined);
+      frame->link_mtu = tun_mtu + TUN_LINK_DELTA (frame);
+    }
+  else
+    {
+      ASSERT (link_mtu_defined);
+      frame->link_mtu = link_mtu;
+    }
+
+  if (TUN_MTU_SIZE (frame) < TUN_MTU_MIN)
+    {
+      msg (M_WARN, "TUN MTU value (%d) must be at least %d", TUN_MTU_SIZE (frame), TUN_MTU_MIN);
+      frame_print (frame, M_FATAL, "MTU is too small");
+    }
+
+  frame->link_mtu_dynamic = frame->link_mtu;
+
+  frame->extra_buffer += PAYLOAD_ALIGN;
+}
+
+/*
+ * Set the tun MTU dynamically.
+ */
+void
+frame_set_mtu_dynamic (struct frame *frame, int mtu, unsigned int flags)
+{
+
+#ifdef ENABLE_DEBUG
+  const int orig_mtu = mtu;
+  const int orig_link_mtu_dynamic = frame->link_mtu_dynamic;
+#endif
+
+  ASSERT (mtu >= 0);
+
+  if (flags & SET_MTU_TUN)
+    mtu += TUN_LINK_DELTA (frame);
+
+  if (!(flags & SET_MTU_UPPER_BOUND) || mtu < frame->link_mtu_dynamic)
+    {
+      frame->link_mtu_dynamic = constrain_int (
+	mtu,
+	EXPANDED_SIZE_MIN (frame),
+	EXPANDED_SIZE (frame));
+    }
+
+  dmsg (D_MTU_DEBUG, "MTU DYNAMIC mtu=%d, flags=%u, %d -> %d",
+       orig_mtu,
+       flags,
+       orig_link_mtu_dynamic,
+       frame->link_mtu_dynamic);
+}
+
+/*
+ * Move extra_frame octets into extra_tun.  Used by fragmenting code
+ * to adjust frame relative to its position in the buffer processing
+ * queue.
+ */
+void
+frame_subtract_extra (struct frame *frame, const struct frame *src)
+{
+  frame->extra_frame -= src->extra_frame;
+  frame->extra_tun   += src->extra_frame;
+}
+
+void
+frame_print (const struct frame *frame,
+	     int level,
+	     const char *prefix)
+{
+  struct gc_arena gc = gc_new ();
+  struct buffer out = alloc_buf_gc (256, &gc);
+  if (prefix)
+    buf_printf (&out, "%s ", prefix);
+  buf_printf (&out, "[");
+  buf_printf (&out, " L:%d", frame->link_mtu);
+  buf_printf (&out, " D:%d", frame->link_mtu_dynamic);
+  buf_printf (&out, " EF:%d", frame->extra_frame);
+  buf_printf (&out, " EB:%d", frame->extra_buffer);
+  buf_printf (&out, " ET:%d", frame->extra_tun);
+  buf_printf (&out, " EL:%d", frame->extra_link);
+  if (frame->align_flags && frame->align_adjust)
+    buf_printf (&out, " AF:%u/%d", frame->align_flags, frame->align_adjust);
+  buf_printf (&out, " ]");
+
+  msg (level, "%s", out.data);
+  gc_free (&gc);
+}
+
+#define MTUDISC_NOT_SUPPORTED_MSG "--mtu-disc is not supported on this OS"
+
+void
+set_mtu_discover_type (int sd, int mtu_type)
+{
+  if (mtu_type >= 0)
+    {
+#if defined(HAVE_SETSOCKOPT) && defined(SOL_IP) && defined(IP_MTU_DISCOVER)
+      if (setsockopt
+	  (sd, SOL_IP, IP_MTU_DISCOVER, &mtu_type, sizeof (mtu_type)))
+	msg (M_ERR, "Error setting IP_MTU_DISCOVER type=%d on TCP/UDP socket",
+	     mtu_type);
+#else
+      msg (M_FATAL, MTUDISC_NOT_SUPPORTED_MSG);
+#endif
+    }
+}
+
+int
+translate_mtu_discover_type_name (const char *name)
+{
+#if defined(IP_PMTUDISC_DONT) && defined(IP_PMTUDISC_WANT) && defined(IP_PMTUDISC_DO)
+  if (!strcmp (name, "yes"))
+    return IP_PMTUDISC_DO;
+  if (!strcmp (name, "maybe"))
+    return IP_PMTUDISC_WANT;
+  if (!strcmp (name, "no"))
+    return IP_PMTUDISC_DONT;
+  msg (M_FATAL,
+       "invalid --mtu-disc type: '%s' -- valid types are 'yes', 'maybe', or 'no'",
+       name);
+#else
+  msg (M_FATAL, MTUDISC_NOT_SUPPORTED_MSG);
+#endif
+  return -1;			/* NOTREACHED */
+}
+
+#if EXTENDED_SOCKET_ERROR_CAPABILITY
+
+struct probehdr
+{
+  uint32_t ttl;
+  struct timeval tv;
+};
+
+const char *
+format_extended_socket_error (int fd, int *mtu, struct gc_arena *gc)
+{
+  int res;
+  struct probehdr rcvbuf;
+  struct iovec iov;
+  struct msghdr msg;
+  struct cmsghdr *cmsg;
+  struct sock_extended_err *e;
+  struct sockaddr_in addr;
+  struct buffer out = alloc_buf_gc (256, gc);
+  char *cbuf = (char *) gc_malloc (256, false, gc);
+
+  *mtu = 0;
+
+  while (true)
+    {
+      memset (&rcvbuf, -1, sizeof (rcvbuf));
+      iov.iov_base = &rcvbuf;
+      iov.iov_len = sizeof (rcvbuf);
+      msg.msg_name = (uint8_t *) &addr;
+      msg.msg_namelen = sizeof (addr);
+      msg.msg_iov = &iov;
+      msg.msg_iovlen = 1;
+      msg.msg_flags = 0;
+      msg.msg_control = cbuf;
+      msg.msg_controllen = 256; /* size of cbuf */
+
+      res = recvmsg (fd, &msg, MSG_ERRQUEUE);
+      if (res < 0)
+	goto exit;
+
+      e = NULL;
+
+      for (cmsg = CMSG_FIRSTHDR (&msg); cmsg; cmsg = CMSG_NXTHDR (&msg, cmsg))
+	{
+	  if (cmsg->cmsg_level == SOL_IP)
+	    {
+	      if (cmsg->cmsg_type == IP_RECVERR)
+		{
+		  e = (struct sock_extended_err *) CMSG_DATA (cmsg);
+		}
+	      else
+		{
+		  buf_printf (&out ,"CMSG=%d|", cmsg->cmsg_type);
+		}
+	    }
+	}
+      if (e == NULL)
+	{
+	  buf_printf (&out, "NO-INFO|");
+	  goto exit;
+	}
+
+      switch (e->ee_errno)
+	{
+	case ETIMEDOUT:
+	  buf_printf (&out, "ETIMEDOUT|");
+	  break;
+	case EMSGSIZE:
+	  buf_printf (&out, "EMSGSIZE Path-MTU=%d|", e->ee_info);
+	  *mtu = e->ee_info;
+	  break;
+	case ECONNREFUSED:
+	  buf_printf (&out, "ECONNREFUSED|");
+	  break;
+	case EPROTO:
+	  buf_printf (&out, "EPROTO|");
+	  break;
+	case EHOSTUNREACH:
+	  buf_printf (&out, "EHOSTUNREACH|");
+	  break;
+	case ENETUNREACH:
+	  buf_printf (&out, "ENETUNREACH|");
+	  break;
+	case EACCES:
+	  buf_printf (&out, "EACCES|");
+	  break;
+	default:
+	  buf_printf (&out, "UNKNOWN|");
+	  break;
+	}
+    }
+
+ exit:
+  buf_rmtail (&out, '|');
+  return BSTR (&out);
+}
+
+void
+set_sock_extended_error_passing (int sd)
+{
+  int on = 1;
+  if (setsockopt (sd, SOL_IP, IP_RECVERR, &on, sizeof (on)))
+    msg (M_WARN | M_ERRNO,
+	 "Note: enable extended error passing on TCP/UDP socket failed (IP_RECVERR)");
+}
+
+#endif