diff options
Diffstat (limited to 'gremlin.c')
| -rw-r--r-- | gremlin.c | 215 |
1 files changed, 0 insertions, 215 deletions
diff --git a/gremlin.c b/gremlin.c deleted file mode 100644 index c7c0206..0000000 --- a/gremlin.c +++ /dev/null @@ -1,215 +0,0 @@ -/* - * 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 - */ - -/* - * Test protocol robustness by simulating dropped packets and - * network outages when the --gremlin option is used. - */ - -#include "syshead.h" - -#ifdef ENABLE_DEBUG - -#include "error.h" -#include "common.h" -#include "misc.h" -#include "otime.h" -#include "gremlin.h" - -#include "memdbg.h" - -/* - * Parameters for packet corruption and droppage. - * Each parameter has 4 possible levels, 0 = disabled, - * while 1, 2, and 3 are enumerated in the below arrays. - * The parameter is a 2-bit field within the --gremlin - * parameter. - */ - -/* - * Probability that we will drop a packet is 1 / n - */ -static const int drop_freq[] = { 500, 100, 50 }; - -/* - * Probability that we will corrupt a packet is 1 / n - */ -static const int corrupt_freq[] = { 500, 100, 50 }; - -/* - * When network goes up, it will be up for between - * UP_LOW and UP_HIGH seconds. - */ -static const int up_low[] = { 60, 10, 5 }; -static const int up_high[] = { 600, 60, 10 }; - -/* - * When network goes down, it will be down for between - * DOWN_LOW and DOWN_HIGH seconds. - */ -static const int down_low[] = { 5, 10, 10 }; -static const int down_high[] = { 10, 60, 120 }; - -/* - * Packet flood levels: - * { number of packets, packet size } - */ -static const struct packet_flood_parms packet_flood_data[] = - {{10, 100}, {10, 1500}, {100, 1500}}; - -struct packet_flood_parms -get_packet_flood_parms (int level) -{ - ASSERT (level > 0 && level < 4); - return packet_flood_data [level - 1]; -} - -/* - * Return true with probability 1/n - */ -static bool flip(int n) { - return (get_random() % n) == 0; -} - -/* - * Return uniformly distributed random number between - * low and high. - */ -static int roll(int low, int high) { - int ret; - ASSERT (low <= high); - ret = low + (get_random() % (high - low + 1)); - ASSERT (ret >= low && ret <= high); - return ret; -} - -static bool initialized; /* GLOBAL */ -static bool up; /* GLOBAL */ -static time_t next; /* GLOBAL */ - -/* - * Return false if we should drop a packet. - */ -bool -ask_gremlin (int flags) -{ - const int up_down_level = GREMLIN_UP_DOWN_LEVEL (flags); - const int drop_level = GREMLIN_DROP_LEVEL (flags); - - if (!initialized) - { - initialized = true; - - if (up_down_level) - up = false; - else - up = true; - - next = now; - } - - if (up_down_level) /* change up/down state? */ - { - if (now >= next) - { - int delta; - if (up) - { - delta = roll (down_low[up_down_level-1], down_high[up_down_level-1]); - up = false; - } - else - { - delta = roll (up_low[up_down_level-1], up_high[up_down_level-1]); - up = true; - } - - msg (D_GREMLIN, - "GREMLIN: CONNECTION GOING %s FOR %d SECONDS", - (up ? "UP" : "DOWN"), - delta); - next = now + delta; - } - } - - if (drop_level) - { - if (up && flip (drop_freq[drop_level-1])) - { - dmsg (D_GREMLIN_VERBOSE, "GREMLIN: Random packet drop"); - return false; - } - } - - return up; -} - -/* - * Possibly corrupt a packet. - */ -void corrupt_gremlin (struct buffer *buf, int flags) { - const int corrupt_level = GREMLIN_CORRUPT_LEVEL (flags); - if (corrupt_level) - { - if (flip (corrupt_freq[corrupt_level-1])) - { - do - { - if (buf->len > 0) - { - uint8_t r = roll (0, 255); - int method = roll (0, 5); - - switch (method) { - case 0: /* corrupt the first byte */ - *BPTR (buf) = r; - break; - case 1: /* corrupt the last byte */ - *(BPTR (buf) + buf->len - 1) = r; - break; - case 2: /* corrupt a random byte */ - *(BPTR(buf) + roll (0, buf->len - 1)) = r; - break; - case 3: /* append a random byte */ - buf_write (buf, &r, 1); - break; - case 4: /* reduce length by 1 */ - --buf->len; - break; - case 5: /* reduce length by a random amount */ - buf->len -= roll (0, buf->len - 1); - break; - } - dmsg (D_GREMLIN_VERBOSE, "GREMLIN: Packet Corruption, method=%d", method); - } - else - break; - } while (flip (2)); /* a 50% chance we will corrupt again */ - } - } -} - -#else -static void dummy(void) {} -#endif |