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-rw-r--r--src/openvpn/occ.c399
1 files changed, 399 insertions, 0 deletions
diff --git a/src/openvpn/occ.c b/src/openvpn/occ.c
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+++ b/src/openvpn/occ.c
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+/*
+ * 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
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#elif defined(_MSC_VER)
+#include "config-msvc.h"
+#endif
+
+#include "syshead.h"
+
+#ifdef ENABLE_OCC
+
+#include "occ.h"
+
+#include "memdbg.h"
+
+#include "forward-inline.h"
+#include "occ-inline.h"
+
+/*
+ * This random string identifies an OpenVPN
+ * Configuration Control packet.
+ * It should be of sufficient length and randomness
+ * so as not to collide with other tunnel data.
+ *
+ * The OCC protocol is as follows:
+ *
+ * occ_magic -- (16 octets)
+ *
+ * type [OCC_REQUEST | OCC_REPLY] (1 octet)
+ * null terminated options string if OCC_REPLY (variable)
+ *
+ * When encryption is used, the OCC packet
+ * is encapsulated within the encrypted
+ * envelope.
+ *
+ * OCC_STRING_SIZE must be set to sizeof (occ_magic)
+ */
+
+const uint8_t occ_magic[] = {
+ 0x28, 0x7f, 0x34, 0x6b, 0xd4, 0xef, 0x7a, 0x81,
+ 0x2d, 0x56, 0xb8, 0xd3, 0xaf, 0xc5, 0x45, 0x9c
+};
+
+static const struct mtu_load_test mtu_load_test_sequence[] = {
+
+ {OCC_MTU_LOAD_REQUEST, -1000},
+ {OCC_MTU_LOAD, -1000},
+ {OCC_MTU_LOAD_REQUEST, -1000},
+ {OCC_MTU_LOAD, -1000},
+ {OCC_MTU_LOAD_REQUEST, -1000},
+ {OCC_MTU_LOAD, -1000},
+
+ {OCC_MTU_LOAD_REQUEST, -750},
+ {OCC_MTU_LOAD, -750},
+ {OCC_MTU_LOAD_REQUEST, -750},
+ {OCC_MTU_LOAD, -750},
+ {OCC_MTU_LOAD_REQUEST, -750},
+ {OCC_MTU_LOAD, -750},
+
+ {OCC_MTU_LOAD_REQUEST, -500},
+ {OCC_MTU_LOAD, -500},
+ {OCC_MTU_LOAD_REQUEST, -500},
+ {OCC_MTU_LOAD, -500},
+ {OCC_MTU_LOAD_REQUEST, -500},
+ {OCC_MTU_LOAD, -500},
+
+ {OCC_MTU_LOAD_REQUEST, -400},
+ {OCC_MTU_LOAD, -400},
+ {OCC_MTU_LOAD_REQUEST, -400},
+ {OCC_MTU_LOAD, -400},
+ {OCC_MTU_LOAD_REQUEST, -400},
+ {OCC_MTU_LOAD, -400},
+
+ {OCC_MTU_LOAD_REQUEST, -300},
+ {OCC_MTU_LOAD, -300},
+ {OCC_MTU_LOAD_REQUEST, -300},
+ {OCC_MTU_LOAD, -300},
+ {OCC_MTU_LOAD_REQUEST, -300},
+ {OCC_MTU_LOAD, -300},
+
+ {OCC_MTU_LOAD_REQUEST, -200},
+ {OCC_MTU_LOAD, -200},
+ {OCC_MTU_LOAD_REQUEST, -200},
+ {OCC_MTU_LOAD, -200},
+ {OCC_MTU_LOAD_REQUEST, -200},
+ {OCC_MTU_LOAD, -200},
+
+ {OCC_MTU_LOAD_REQUEST, -150},
+ {OCC_MTU_LOAD, -150},
+ {OCC_MTU_LOAD_REQUEST, -150},
+ {OCC_MTU_LOAD, -150},
+ {OCC_MTU_LOAD_REQUEST, -150},
+ {OCC_MTU_LOAD, -150},
+
+ {OCC_MTU_LOAD_REQUEST, -100},
+ {OCC_MTU_LOAD, -100},
+ {OCC_MTU_LOAD_REQUEST, -100},
+ {OCC_MTU_LOAD, -100},
+ {OCC_MTU_LOAD_REQUEST, -100},
+ {OCC_MTU_LOAD, -100},
+
+ {OCC_MTU_LOAD_REQUEST, -50},
+ {OCC_MTU_LOAD, -50},
+ {OCC_MTU_LOAD_REQUEST, -50},
+ {OCC_MTU_LOAD, -50},
+ {OCC_MTU_LOAD_REQUEST, -50},
+ {OCC_MTU_LOAD, -50},
+
+ {OCC_MTU_LOAD_REQUEST, 0},
+ {OCC_MTU_LOAD, 0},
+ {OCC_MTU_LOAD_REQUEST, 0},
+ {OCC_MTU_LOAD, 0},
+ {OCC_MTU_LOAD_REQUEST, 0},
+ {OCC_MTU_LOAD, 0},
+
+ {OCC_MTU_REQUEST, 0},
+ {OCC_MTU_REQUEST, 0},
+ {OCC_MTU_REQUEST, 0},
+ {OCC_MTU_REQUEST, 0},
+ {OCC_MTU_REQUEST, 0},
+ {OCC_MTU_REQUEST, 0},
+ {OCC_MTU_REQUEST, 0},
+ {OCC_MTU_REQUEST, 0},
+ {OCC_MTU_REQUEST, 0},
+ {OCC_MTU_REQUEST, 0},
+
+ {-1, 0}
+};
+
+void
+check_send_occ_req_dowork (struct context *c)
+{
+ if (++c->c2.occ_n_tries >= OCC_N_TRIES)
+ {
+ if (c->options.ce.remote)
+ /*
+ * No OCC_REPLY from peer after repeated attempts.
+ * Give up.
+ */
+ msg (D_SHOW_OCC,
+ "NOTE: failed to obtain options consistency info from peer -- "
+ "this could occur if the remote peer is running a version of "
+ PACKAGE_NAME
+ " before 1.5-beta8 or if there is a network connectivity problem, and will not necessarily prevent "
+ PACKAGE_NAME
+ " from running (" counter_format " bytes received from peer, " counter_format
+ " bytes authenticated data channel traffic) -- you can disable the options consistency "
+ "check with --disable-occ.",
+ c->c2.link_read_bytes,
+ c->c2.link_read_bytes_auth);
+ event_timeout_clear (&c->c2.occ_interval);
+ }
+ else
+ {
+ c->c2.occ_op = OCC_REQUEST;
+
+ /*
+ * If we don't hear back from peer, send another
+ * OCC_REQUEST in OCC_INTERVAL_SECONDS.
+ */
+ event_timeout_reset (&c->c2.occ_interval);
+ }
+}
+
+void
+check_send_occ_load_test_dowork (struct context *c)
+{
+ if (CONNECTION_ESTABLISHED (c))
+ {
+ const struct mtu_load_test *entry;
+
+ if (!c->c2.occ_mtu_load_n_tries)
+ msg (M_INFO,
+ "NOTE: Beginning empirical MTU test -- results should be available in 3 to 4 minutes.");
+
+ entry = &mtu_load_test_sequence[c->c2.occ_mtu_load_n_tries++];
+ if (entry->op >= 0)
+ {
+ c->c2.occ_op = entry->op;
+ c->c2.occ_mtu_load_size =
+ EXPANDED_SIZE (&c->c2.frame) + entry->delta;
+ }
+ else
+ {
+ msg (M_INFO,
+ "NOTE: failed to empirically measure MTU (requires " PACKAGE_NAME " 1.5 or higher at other end of connection).");
+ event_timeout_clear (&c->c2.occ_mtu_load_test_interval);
+ c->c2.occ_mtu_load_n_tries = 0;
+ }
+ }
+}
+
+void
+check_send_occ_msg_dowork (struct context *c)
+{
+ bool doit = false;
+
+ c->c2.buf = c->c2.buffers->aux_buf;
+ ASSERT (buf_init (&c->c2.buf, FRAME_HEADROOM (&c->c2.frame)));
+ ASSERT (buf_safe (&c->c2.buf, MAX_RW_SIZE_TUN (&c->c2.frame)));
+ ASSERT (buf_write (&c->c2.buf, occ_magic, OCC_STRING_SIZE));
+
+ switch (c->c2.occ_op)
+ {
+ case OCC_REQUEST:
+ if (!buf_write_u8 (&c->c2.buf, OCC_REQUEST))
+ break;
+ dmsg (D_PACKET_CONTENT, "SENT OCC_REQUEST");
+ doit = true;
+ break;
+
+ case OCC_REPLY:
+ if (!c->c2.options_string_local)
+ break;
+ if (!buf_write_u8 (&c->c2.buf, OCC_REPLY))
+ break;
+ if (!buf_write (&c->c2.buf, c->c2.options_string_local,
+ strlen (c->c2.options_string_local) + 1))
+ break;
+ dmsg (D_PACKET_CONTENT, "SENT OCC_REPLY");
+ doit = true;
+ break;
+
+ case OCC_MTU_REQUEST:
+ if (!buf_write_u8 (&c->c2.buf, OCC_MTU_REQUEST))
+ break;
+ dmsg (D_PACKET_CONTENT, "SENT OCC_MTU_REQUEST");
+ doit = true;
+ break;
+
+ case OCC_MTU_REPLY:
+ if (!buf_write_u8 (&c->c2.buf, OCC_MTU_REPLY))
+ break;
+ if (!buf_write_u16 (&c->c2.buf, c->c2.max_recv_size_local))
+ break;
+ if (!buf_write_u16 (&c->c2.buf, c->c2.max_send_size_local))
+ break;
+ dmsg (D_PACKET_CONTENT, "SENT OCC_MTU_REPLY");
+ doit = true;
+ break;
+
+ case OCC_MTU_LOAD_REQUEST:
+ if (!buf_write_u8 (&c->c2.buf, OCC_MTU_LOAD_REQUEST))
+ break;
+ if (!buf_write_u16 (&c->c2.buf, c->c2.occ_mtu_load_size))
+ break;
+ dmsg (D_PACKET_CONTENT, "SENT OCC_MTU_LOAD_REQUEST");
+ doit = true;
+ break;
+
+ case OCC_MTU_LOAD:
+ {
+ int need_to_add;
+
+ if (!buf_write_u8 (&c->c2.buf, OCC_MTU_LOAD))
+ break;
+ need_to_add = min_int (c->c2.occ_mtu_load_size, EXPANDED_SIZE (&c->c2.frame))
+ - OCC_STRING_SIZE
+ - sizeof (uint8_t)
+ - EXTRA_FRAME (&c->c2.frame);
+
+ while (need_to_add > 0)
+ {
+ /*
+ * Fill the load test packet with pseudo-random bytes.
+ */
+ if (!buf_write_u8 (&c->c2.buf, get_random () & 0xFF))
+ break;
+ --need_to_add;
+ }
+ dmsg (D_PACKET_CONTENT, "SENT OCC_MTU_LOAD min_int(%d-%d-%d-%d,%d) size=%d",
+ c->c2.occ_mtu_load_size,
+ OCC_STRING_SIZE,
+ (int) sizeof (uint8_t),
+ EXTRA_FRAME (&c->c2.frame),
+ MAX_RW_SIZE_TUN (&c->c2.frame),
+ BLEN (&c->c2.buf));
+ doit = true;
+ }
+ break;
+
+ case OCC_EXIT:
+ if (!buf_write_u8 (&c->c2.buf, OCC_EXIT))
+ break;
+ dmsg (D_PACKET_CONTENT, "SENT OCC_EXIT");
+ doit = true;
+ break;
+ }
+
+ if (doit)
+ {
+ /*
+ * We will treat the packet like any other outgoing packet,
+ * compress, encrypt, sign, etc.
+ */
+ encrypt_sign (c, true);
+ }
+
+ c->c2.occ_op = -1;
+}
+
+void
+process_received_occ_msg (struct context *c)
+{
+ ASSERT (buf_advance (&c->c2.buf, OCC_STRING_SIZE));
+ switch (buf_read_u8 (&c->c2.buf))
+ {
+ case OCC_REQUEST:
+ dmsg (D_PACKET_CONTENT, "RECEIVED OCC_REQUEST");
+ c->c2.occ_op = OCC_REPLY;
+ break;
+
+ case OCC_MTU_REQUEST:
+ dmsg (D_PACKET_CONTENT, "RECEIVED OCC_MTU_REQUEST");
+ c->c2.occ_op = OCC_MTU_REPLY;
+ break;
+
+ case OCC_MTU_LOAD_REQUEST:
+ dmsg (D_PACKET_CONTENT, "RECEIVED OCC_MTU_LOAD_REQUEST");
+ c->c2.occ_mtu_load_size = buf_read_u16 (&c->c2.buf);
+ if (c->c2.occ_mtu_load_size >= 0)
+ c->c2.occ_op = OCC_MTU_LOAD;
+ break;
+
+ case OCC_REPLY:
+ dmsg (D_PACKET_CONTENT, "RECEIVED OCC_REPLY");
+ if (c->options.occ && !TLS_MODE (c) && c->c2.options_string_remote)
+ {
+ if (!options_cmp_equal_safe ((char *) BPTR (&c->c2.buf),
+ c->c2.options_string_remote,
+ c->c2.buf.len))
+ {
+ options_warning_safe ((char *) BPTR (&c->c2.buf),
+ c->c2.options_string_remote,
+ c->c2.buf.len);
+ }
+ }
+ event_timeout_clear (&c->c2.occ_interval);
+ break;
+
+ case OCC_MTU_REPLY:
+ dmsg (D_PACKET_CONTENT, "RECEIVED OCC_MTU_REPLY");
+ c->c2.max_recv_size_remote = buf_read_u16 (&c->c2.buf);
+ c->c2.max_send_size_remote = buf_read_u16 (&c->c2.buf);
+ if (c->options.mtu_test
+ && c->c2.max_recv_size_remote > 0
+ && c->c2.max_send_size_remote > 0)
+ {
+ msg (M_INFO, "NOTE: Empirical MTU test completed [Tried,Actual] local->remote=[%d,%d] remote->local=[%d,%d]",
+ c->c2.max_send_size_local,
+ c->c2.max_recv_size_remote,
+ c->c2.max_send_size_remote,
+ c->c2.max_recv_size_local);
+ if (!c->options.ce.fragment
+ && (proto_is_dgram(c->options.ce.proto))
+ && c->c2.max_send_size_local > TUN_MTU_MIN
+ && (c->c2.max_recv_size_remote < c->c2.max_send_size_local
+ || c->c2.max_recv_size_local < c->c2.max_send_size_remote))
+ msg (M_INFO, "NOTE: This connection is unable to accomodate a UDP packet size of %d. Consider using --fragment or --mssfix options as a workaround.",
+ c->c2.max_send_size_local);
+ }
+ event_timeout_clear (&c->c2.occ_mtu_load_test_interval);
+ break;
+
+ case OCC_EXIT:
+ dmsg (D_PACKET_CONTENT, "RECEIVED OCC_EXIT");
+ c->sig->signal_received = SIGTERM;
+ c->sig->signal_text = "remote-exit";
+ break;
+ }
+ c->c2.buf.len = 0; /* don't pass packet on */
+}
+
+#else
+static void dummy(void) {}
+#endif
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