diff options
Diffstat (limited to 'src/openvpn/gremlin.c')
| -rw-r--r-- | src/openvpn/gremlin.c | 204 |
1 files changed, 110 insertions, 94 deletions
diff --git a/src/openvpn/gremlin.c b/src/openvpn/gremlin.c index f0aa7f6..5bff5e8 100644 --- a/src/openvpn/gremlin.c +++ b/src/openvpn/gremlin.c @@ -5,7 +5,7 @@ * packet encryption, packet authentication, and * packet compression. * - * Copyright (C) 2002-2010 OpenVPN Technologies, Inc. <sales@openvpn.net> + * Copyright (C) 2002-2017 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 @@ -82,32 +82,34 @@ static const int down_high[] = { 10, 60, 120 }; * { number of packets, packet size } */ static const struct packet_flood_parms packet_flood_data[] = - {{10, 100}, {10, 1500}, {100, 1500}}; +{{10, 100}, {10, 1500}, {100, 1500}}; struct packet_flood_parms -get_packet_flood_parms (int level) +get_packet_flood_parms(int level) { - ASSERT (level > 0 && level < 4); - return packet_flood_data [level - 1]; + 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; +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 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 */ @@ -118,104 +120,118 @@ static time_t next; /* GLOBAL */ * Return false if we should drop a packet. */ bool -ask_gremlin (int flags) +ask_gremlin(int flags) { - const int up_down_level = GREMLIN_UP_DOWN_LEVEL (flags); - const int drop_level = GREMLIN_DROP_LEVEL (flags); + const int up_down_level = GREMLIN_UP_DOWN_LEVEL(flags); + const int drop_level = GREMLIN_DROP_LEVEL(flags); - if (!initialized) + if (!initialized) { - initialized = true; - - if (up_down_level) - up = false; - else - up = true; - - next = now; + initialized = true; + + if (up_down_level) + { + up = false; + } + else + { + up = true; + } + + next = now; } - if (up_down_level) /* change up/down state? */ + 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 (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 (drop_level) { - if (up && flip (drop_freq[drop_level-1])) - { - dmsg (D_GREMLIN_VERBOSE, "GREMLIN: Random packet drop"); - return false; - } + if (up && flip(drop_freq[drop_level-1])) + { + dmsg(D_GREMLIN_VERBOSE, "GREMLIN: Random packet drop"); + return false; + } } - return up; + 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) +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 */ - } + 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 +#else /* ifdef ENABLE_DEBUG */ +static void +dummy(void) { +} +#endif /* ifdef ENABLE_DEBUG */ |