Imported Upstream version 2.3_rc1

1 files changed, 757 insertions, 0 deletions

diff --git a/src/openvpn/reliable.c b/src/openvpn/reliable.c
new file mode 100644
index 0000000..763169e
--- /dev/null
+++ b/src/openvpn/reliable.c
@@ -0,0 +1,757 @@
+/*
+ *  OpenVPN -- An application to securely tunnel IP networks
+ *             over a single 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
+ */
+
+/*
+ * These routines implement a reliability layer on top of UDP,
+ * so that SSL/TLS can be run over UDP.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#elif defined(_MSC_VER)
+#include "config-msvc.h"
+#endif
+
+#include "syshead.h"
+
+#if defined(ENABLE_CRYPTO) && defined(ENABLE_SSL)
+
+#include "buffer.h"
+#include "error.h"
+#include "common.h"
+#include "reliable.h"
+
+#include "memdbg.h"
+
+/*
+ * verify that test - base < extent while allowing for base or test wraparound
+ */
+static inline bool
+reliable_pid_in_range1 (const packet_id_type test,
+			const packet_id_type base,
+			const unsigned int extent)
+{
+  if (test >= base)
+    {
+      if (test - base < extent)
+	return true;
+    }
+  else
+    {
+      if ((test+0x80000000u) - (base+0x80000000u) < extent)
+	return true;
+    }
+
+  return false;
+}
+
+/*
+ * verify that test < base + extent while allowing for base or test wraparound
+ */
+static inline bool
+reliable_pid_in_range2 (const packet_id_type test,
+			const packet_id_type base,
+			const unsigned int extent)
+{
+  if (base + extent >= base)
+    {
+      if (test < base + extent)
+	return true;
+    }
+  else
+    {
+      if ((test+0x80000000u) < (base+0x80000000u) + extent)
+	return true;
+    }
+
+  return false;
+}
+
+/*
+ * verify that p1 < p2  while allowing for p1 or p2 wraparound
+ */
+static inline bool
+reliable_pid_min (const packet_id_type p1,
+		  const packet_id_type p2)
+{
+  return !reliable_pid_in_range1 (p1, p2, 0x80000000u);
+}
+
+/* check if a particular packet_id is present in ack */
+static inline bool
+reliable_ack_packet_id_present (struct reliable_ack *ack, packet_id_type pid)
+{
+  int i;
+  for (i = 0; i < ack->len; ++i)
+    if (ack->packet_id[i] == pid)
+      return true;
+  return false;
+}
+
+/* get a packet_id from buf */
+bool
+reliable_ack_read_packet_id (struct buffer *buf, packet_id_type *pid)
+{
+  packet_id_type net_pid;
+
+  if (buf_read (buf, &net_pid, sizeof (net_pid)))
+    {
+      *pid = ntohpid (net_pid);
+      dmsg (D_REL_DEBUG, "ACK read ID " packet_id_format " (buf->len=%d)",
+	   (packet_id_print_type)*pid, buf->len);
+      return true;
+    }
+
+  dmsg (D_REL_LOW, "ACK read ID FAILED (buf->len=%d)", buf->len);
+  return false;
+}
+
+/* acknowledge a packet_id by adding it to a struct reliable_ack */
+bool
+reliable_ack_acknowledge_packet_id (struct reliable_ack *ack, packet_id_type pid)
+{
+  if (!reliable_ack_packet_id_present (ack, pid) && ack->len < RELIABLE_ACK_SIZE)
+    {
+      ack->packet_id[ack->len++] = pid;
+      dmsg (D_REL_DEBUG, "ACK acknowledge ID " packet_id_format " (ack->len=%d)",
+	   (packet_id_print_type)pid, ack->len);
+      return true;
+    }
+
+  dmsg (D_REL_LOW, "ACK acknowledge ID " packet_id_format " FAILED (ack->len=%d)",
+       (packet_id_print_type)pid, ack->len);
+  return false;
+}
+
+/* read a packet ID acknowledgement record from buf into ack */
+bool
+reliable_ack_read (struct reliable_ack * ack,
+		   struct buffer * buf, const struct session_id * sid)
+{
+  struct gc_arena gc = gc_new ();
+  int i;
+  uint8_t count;
+  packet_id_type net_pid;
+  packet_id_type pid;
+  struct session_id session_id_remote;
+
+  if (!buf_read (buf, &count, sizeof (count)))
+    goto error;
+  for (i = 0; i < count; ++i)
+    {
+      if (!buf_read (buf, &net_pid, sizeof (net_pid)))
+	goto error;
+      if (ack->len >= RELIABLE_ACK_SIZE)
+	goto error;
+      pid = ntohpid (net_pid);
+      ack->packet_id[ack->len++] = pid;
+    }
+  if (count)
+    {
+      if (!session_id_read (&session_id_remote, buf))
+	goto error;
+      if (!session_id_defined (&session_id_remote) ||
+	  !session_id_equal (&session_id_remote, sid))
+	{
+	  dmsg (D_REL_LOW,
+	       "ACK read BAD SESSION-ID FROM REMOTE, local=%s, remote=%s",
+	       session_id_print (sid, &gc), session_id_print (&session_id_remote, &gc));
+	  goto error;
+	}
+    }
+  gc_free (&gc);
+  return true;
+
+error:
+  gc_free (&gc);
+  return false;
+}
+
+#define ACK_SIZE(n) (sizeof (uint8_t) + ((n) ? SID_SIZE : 0) + sizeof (packet_id_type) * (n))
+
+/* write a packet ID acknowledgement record to buf, */
+/* removing all acknowledged entries from ack */
+bool
+reliable_ack_write (struct reliable_ack * ack,
+		    struct buffer * buf,
+		    const struct session_id * sid, int max, bool prepend)
+{
+  int i, j;
+  uint8_t n;
+  struct buffer sub;
+
+  n = ack->len;
+  if (n > max)
+    n = max;
+  sub = buf_sub (buf, ACK_SIZE(n), prepend);
+  if (!BDEF (&sub))
+    goto error;
+  ASSERT (buf_write (&sub, &n, sizeof (n)));
+  for (i = 0; i < n; ++i)
+    {
+      packet_id_type pid = ack->packet_id[i];
+      packet_id_type net_pid = htonpid (pid);
+      ASSERT (buf_write (&sub, &net_pid, sizeof (net_pid)));
+      dmsg (D_REL_DEBUG, "ACK write ID " packet_id_format " (ack->len=%d, n=%d)", (packet_id_print_type)pid, ack->len, n);
+    }
+  if (n)
+    {
+      ASSERT (session_id_defined (sid));
+      ASSERT (session_id_write (sid, &sub));
+      for (i = 0, j = n; j < ack->len;)
+	ack->packet_id[i++] = ack->packet_id[j++];
+      ack->len = i;
+    }
+
+  return true;
+
+error:
+  return false;
+}
+
+/* add to extra_frame the maximum number of bytes we will need for reliable_ack_write */
+void
+reliable_ack_adjust_frame_parameters (struct frame* frame, int max)
+{
+  frame_add_to_extra_frame (frame, ACK_SIZE (max));
+}
+
+/* print a reliable ACK record coming off the wire */
+const char *
+reliable_ack_print (struct buffer *buf, bool verbose, struct gc_arena *gc)
+{
+  int i;
+  uint8_t n_ack;
+  struct session_id sid_ack;
+  packet_id_type pid;
+  struct buffer out = alloc_buf_gc (256, gc);
+
+  buf_printf (&out, "[");
+  if (!buf_read (buf, &n_ack, sizeof (n_ack)))
+    goto done;
+  for (i = 0; i < n_ack; ++i)
+    {
+      if (!buf_read (buf, &pid, sizeof (pid)))
+	goto done;
+      pid = ntohpid (pid);
+      buf_printf (&out, " " packet_id_format, (packet_id_print_type)pid);
+    }
+  if (n_ack)
+    {
+      if (!session_id_read (&sid_ack, buf))
+	goto done;
+      if (verbose)
+	buf_printf (&out, " sid=%s", session_id_print (&sid_ack, gc));
+    }
+
+ done:
+  buf_printf (&out, " ]");
+  return BSTR (&out);
+}
+
+/*
+ * struct reliable member functions.
+ */
+
+void
+reliable_init (struct reliable *rel, int buf_size, int offset, int array_size, bool hold)
+{
+  int i;
+
+  CLEAR (*rel);
+  ASSERT (array_size > 0 && array_size <= RELIABLE_CAPACITY);
+  rel->hold = hold;
+  rel->size = array_size;
+  rel->offset = offset;
+  for (i = 0; i < rel->size; ++i)
+    {
+      struct reliable_entry *e = &rel->array[i];
+      e->buf = alloc_buf (buf_size);
+      ASSERT (buf_init (&e->buf, offset));
+    }
+}
+
+void
+reliable_free (struct reliable *rel)
+{
+  int i;
+  for (i = 0; i < rel->size; ++i)
+    {
+      struct reliable_entry *e = &rel->array[i];
+      free_buf (&e->buf);
+    }
+}
+
+/* no active buffers? */
+bool
+reliable_empty (const struct reliable *rel)
+{
+  int i;
+  for (i = 0; i < rel->size; ++i)
+    {
+      const struct reliable_entry *e = &rel->array[i];
+      if (e->active)
+	return false;
+    }
+  return true;
+}
+
+/* del acknowledged items from send buf */
+void
+reliable_send_purge (struct reliable *rel, struct reliable_ack *ack)
+{
+  int i, j;
+  for (i = 0; i < ack->len; ++i)
+    {
+      packet_id_type pid = ack->packet_id[i];
+      for (j = 0; j < rel->size; ++j)
+	{
+	  struct reliable_entry *e = &rel->array[j];
+	  if (e->active && e->packet_id == pid)
+	    {
+	      dmsg (D_REL_DEBUG,
+		   "ACK received for pid " packet_id_format ", deleting from send buffer",
+		   (packet_id_print_type)pid);
+#if 0
+	      /* DEBUGGING -- how close were we timing out on ACK failure and resending? */
+	      {
+		if (e->next_try)
+		  {
+		    const interval_t wake = e->next_try - now;
+		    msg (M_INFO, "ACK " packet_id_format ", wake=%d", pid, wake);
+		  }
+	      }
+#endif
+	      e->active = false;
+	      break;
+	    }
+	}
+    }
+}
+
+/* print the current sequence of active packet IDs */
+static const char *
+reliable_print_ids (const struct reliable *rel, struct gc_arena *gc)
+{
+  struct buffer out = alloc_buf_gc (256, gc);
+  int i;
+
+  buf_printf (&out, "[" packet_id_format "]", (packet_id_print_type)rel->packet_id);
+  for (i = 0; i < rel->size; ++i)
+    {
+      const struct reliable_entry *e = &rel->array[i];
+      if (e->active)
+	buf_printf (&out, " " packet_id_format, (packet_id_print_type)e->packet_id);
+    }
+  return BSTR (&out);
+}
+
+/* true if at least one free buffer available */
+bool
+reliable_can_get (const struct reliable *rel)
+{
+  struct gc_arena gc = gc_new ();
+  int i;
+  for (i = 0; i < rel->size; ++i)
+    {
+      const struct reliable_entry *e = &rel->array[i];
+      if (!e->active)
+	return true;
+    }
+  dmsg (D_REL_LOW, "ACK no free receive buffer available: %s", reliable_print_ids (rel, &gc));
+  gc_free (&gc);
+  return false;
+}
+
+/* make sure that incoming packet ID isn't a replay */
+bool
+reliable_not_replay (const struct reliable *rel, packet_id_type id)
+{
+  struct gc_arena gc = gc_new ();
+  int i;
+  if (reliable_pid_min (id, rel->packet_id))
+    goto bad;
+  for (i = 0; i < rel->size; ++i)
+    {
+      const struct reliable_entry *e = &rel->array[i];
+      if (e->active && e->packet_id == id)
+	goto bad;
+    }
+  gc_free (&gc);
+  return true;
+
+ bad:
+  dmsg (D_REL_DEBUG, "ACK " packet_id_format " is a replay: %s", (packet_id_print_type)id, reliable_print_ids (rel, &gc));
+  gc_free (&gc);
+  return false;
+}
+
+/* make sure that incoming packet ID won't deadlock the receive buffer */
+bool
+reliable_wont_break_sequentiality (const struct reliable *rel, packet_id_type id)
+{
+  struct gc_arena gc = gc_new ();
+
+  const int ret = reliable_pid_in_range2 (id, rel->packet_id, rel->size);
+
+  if (!ret)
+    {
+      dmsg (D_REL_LOW, "ACK " packet_id_format " breaks sequentiality: %s",
+	   (packet_id_print_type)id, reliable_print_ids (rel, &gc));
+    }
+
+  dmsg (D_REL_DEBUG, "ACK RWBS rel->size=%d rel->packet_id=%08x id=%08x ret=%d\n", rel->size, rel->packet_id, id, ret);
+
+  gc_free (&gc);
+  return ret;
+}
+
+/* grab a free buffer */
+struct buffer *
+reliable_get_buf (struct reliable *rel)
+{
+  int i;
+  for (i = 0; i < rel->size; ++i)
+    {
+      struct reliable_entry *e = &rel->array[i];
+      if (!e->active)
+	{
+	  ASSERT (buf_init (&e->buf, rel->offset));
+	  return &e->buf;
+	}
+    }
+  return NULL;
+}
+
+/* grab a free buffer, fail if buffer clogged by unacknowledged low packet IDs */
+struct buffer *
+reliable_get_buf_output_sequenced (struct reliable *rel)
+{
+  struct gc_arena gc = gc_new ();
+  int i;
+  packet_id_type min_id = 0;
+  bool min_id_defined = false;
+  struct buffer *ret = NULL;
+
+  /* find minimum active packet_id */
+  for (i = 0; i < rel->size; ++i)
+    {
+      const struct reliable_entry *e = &rel->array[i];
+      if (e->active)
+	{
+	  if (!min_id_defined || reliable_pid_min (e->packet_id, min_id))
+	    {
+	      min_id_defined = true;
+	      min_id = e->packet_id;
+	    }
+	}
+    }
+
+  if (!min_id_defined || reliable_pid_in_range1 (rel->packet_id, min_id, rel->size))
+    {
+      ret = reliable_get_buf (rel);
+    }
+  else
+    {
+      dmsg (D_REL_LOW, "ACK output sequence broken: %s", reliable_print_ids (rel, &gc));
+    }
+  gc_free (&gc);
+  return ret;
+}
+
+/* get active buffer for next sequentially increasing key ID */
+struct buffer *
+reliable_get_buf_sequenced (struct reliable *rel)
+{
+  int i;
+  for (i = 0; i < rel->size; ++i)
+    {
+      struct reliable_entry *e = &rel->array[i];
+      if (e->active && e->packet_id == rel->packet_id)
+	{
+	  return &e->buf;
+	}
+    }
+  return NULL;
+}
+
+/* return true if reliable_send would return a non-NULL result */
+bool
+reliable_can_send (const struct reliable *rel)
+{
+  struct gc_arena gc = gc_new ();
+  int i;
+  int n_active = 0, n_current = 0;
+  for (i = 0; i < rel->size; ++i)
+    {
+      const struct reliable_entry *e = &rel->array[i];
+      if (e->active)
+	{
+	  ++n_active;
+	  if (now >= e->next_try)
+	    ++n_current;
+	}
+    }
+  dmsg (D_REL_DEBUG, "ACK reliable_can_send active=%d current=%d : %s",
+       n_active,
+       n_current,
+       reliable_print_ids (rel, &gc));
+
+  gc_free (&gc);
+  return n_current > 0 && !rel->hold;
+}
+
+#ifdef EXPONENTIAL_BACKOFF
+/* return a unique point-in-time to trigger retry */
+static time_t
+reliable_unique_retry (struct reliable *rel, time_t retry)
+{
+  int i;
+  while (true)
+    {
+      for (i = 0; i < rel->size; ++i)
+	{
+	  struct reliable_entry *e = &rel->array[i];
+	  if (e->active && e->next_try == retry)
+	    goto again;
+	}
+      break;
+    again:
+      ++retry;
+    }
+  return retry;
+}
+#endif
+
+/* return next buffer to send to remote */
+struct buffer *
+reliable_send (struct reliable *rel, int *opcode)
+{
+  int i;
+  struct reliable_entry *best = NULL;
+  const time_t local_now = now;
+
+  for (i = 0; i < rel->size; ++i)
+    {
+      struct reliable_entry *e = &rel->array[i];
+      if (e->active && local_now >= e->next_try)
+	{
+	  if (!best || reliable_pid_min (e->packet_id, best->packet_id))
+	    best = e;
+	}
+    }
+  if (best)
+    {
+#ifdef EXPONENTIAL_BACKOFF
+      /* exponential backoff */
+      best->next_try = reliable_unique_retry (rel, local_now + best->timeout);
+      best->timeout *= 2;
+#else
+      /* constant timeout, no backoff */
+      best->next_try = local_now + best->timeout;
+#endif
+      *opcode = best->opcode;
+      dmsg (D_REL_DEBUG, "ACK reliable_send ID " packet_id_format " (size=%d to=%d)",
+	   (packet_id_print_type)best->packet_id, best->buf.len,
+	   (int)(best->next_try - local_now));
+      return &best->buf;
+    }
+  return NULL;
+}
+
+/* schedule all pending packets for immediate retransmit */
+void
+reliable_schedule_now (struct reliable *rel)
+{
+  int i;
+  dmsg (D_REL_DEBUG, "ACK reliable_schedule_now");
+  rel->hold = false;
+  for (i = 0; i < rel->size; ++i)
+    {
+      struct reliable_entry *e = &rel->array[i];
+      if (e->active)
+	{
+	  e->next_try = now;
+	  e->timeout = rel->initial_timeout;
+	}
+    }
+}
+
+/* in how many seconds should we wake up to check for timeout */
+/* if we return BIG_TIMEOUT, nothing to wait for */
+interval_t
+reliable_send_timeout (const struct reliable *rel)
+{
+  struct gc_arena gc = gc_new ();
+  interval_t ret = BIG_TIMEOUT;
+  int i;
+  const time_t local_now = now;
+
+  for (i = 0; i < rel->size; ++i)
+    {
+      const struct reliable_entry *e = &rel->array[i];
+      if (e->active)
+	{
+	  if (e->next_try <= local_now)
+	    {
+	      ret = 0;
+	      break;
+	    }
+	  else
+	    {
+	      ret = min_int (ret, e->next_try - local_now);
+	    }
+	}
+    }
+
+  dmsg (D_REL_DEBUG, "ACK reliable_send_timeout %d %s",
+       (int) ret,
+       reliable_print_ids (rel, &gc));
+
+  gc_free (&gc);
+  return ret;
+}
+
+/*
+ * Enable an incoming buffer previously returned by a get function as active.
+ */
+
+void
+reliable_mark_active_incoming (struct reliable *rel, struct buffer *buf,
+			       packet_id_type pid, int opcode)
+{
+  int i;
+  for (i = 0; i < rel->size; ++i)
+    {
+      struct reliable_entry *e = &rel->array[i];
+      if (buf == &e->buf)
+	{
+	  e->active = true;
+
+	  /* packets may not arrive in sequential order */
+	  e->packet_id = pid;
+
+	  /* check for replay */
+	  ASSERT (!reliable_pid_min (pid, rel->packet_id));
+
+	  e->opcode = opcode;
+	  e->next_try = 0;
+	  e->timeout = 0;
+	  dmsg (D_REL_DEBUG, "ACK mark active incoming ID " packet_id_format, (packet_id_print_type)e->packet_id);
+	  return;
+	}
+    }
+  ASSERT (0);			/* buf not found in rel */
+}
+
+/*
+ * Enable an outgoing buffer previously returned by a get function as active.
+ */
+
+void
+reliable_mark_active_outgoing (struct reliable *rel, struct buffer *buf, int opcode)
+{
+  int i;
+  for (i = 0; i < rel->size; ++i)
+    {
+      struct reliable_entry *e = &rel->array[i];
+      if (buf == &e->buf)
+	{
+	  /* Write mode, increment packet_id (i.e. sequence number)
+	     linearly and prepend id to packet */
+	  packet_id_type net_pid;
+	  e->packet_id = rel->packet_id++;
+	  net_pid = htonpid (e->packet_id);
+	  ASSERT (buf_write_prepend (buf, &net_pid, sizeof (net_pid)));
+	  e->active = true;
+	  e->opcode = opcode;
+	  e->next_try = 0;
+	  e->timeout = rel->initial_timeout;
+	  dmsg (D_REL_DEBUG, "ACK mark active outgoing ID " packet_id_format, (packet_id_print_type)e->packet_id);
+	  return;
+	}
+    }
+  ASSERT (0);			/* buf not found in rel */
+}
+
+/* delete a buffer previously activated by reliable_mark_active() */
+void
+reliable_mark_deleted (struct reliable *rel, struct buffer *buf, bool inc_pid)
+{
+  int i;
+  for (i = 0; i < rel->size; ++i)
+    {
+      struct reliable_entry *e = &rel->array[i];
+      if (buf == &e->buf)
+	{
+	  e->active = false;
+	  if (inc_pid)
+	    rel->packet_id = e->packet_id + 1;
+	  return;
+	}
+    }
+  ASSERT (0);
+}
+
+#if 0
+
+void
+reliable_ack_debug_print (const struct reliable_ack *ack, char *desc)
+{
+  int i;
+
+  printf ("********* struct reliable_ack %s\n", desc);
+  for (i = 0; i < ack->len; ++i)
+    {
+      printf ("  %d: " packet_id_format "\n", i, (packet_id_print_type) ack->packet_id[i]);
+    }
+}
+
+void
+reliable_debug_print (const struct reliable *rel, char *desc)
+{
+  int i;
+  update_time ();
+
+  printf ("********* struct reliable %s\n", desc);
+  printf ("  initial_timeout=%d\n", (int)rel->initial_timeout);
+  printf ("  packet_id=" packet_id_format "\n", rel->packet_id);
+  printf ("  now=" time_format "\n", now);
+  for (i = 0; i < rel->size; ++i)
+    {
+      const struct reliable_entry *e = &rel->array[i];
+      if (e->active)
+	{
+	  printf ("  %d: packet_id=" packet_id_format " len=%d", i, e->packet_id, e->buf.len);
+	  printf (" next_try=" time_format, e->next_try);
+	  printf ("\n");
+	}
+    }
+}
+
+#endif
+
+#else
+static void dummy(void) {}
+#endif /* ENABLE_CRYPTO && ENABLE_SSL*/