"Fossies" - the Fresh Open Source Software Archive  

Source code changes of the file "src/random_numbers.c" between
n2n-2.8.tar.gz and n2n-3.0.tar.gz

About: n2n is a layer-two peer-to-peer virtual private network (VPN) which allows bypassing intermediate firewalls.

random_numbers.c  (n2n-2.8):random_numbers.c  (n2n-3.0)
/** /**
* (C) 2007-20 - ntop.org and contributors * (C) 2007-21 - ntop.org and contributors
* *
* This program is free software; you can redistribute it and/or modify * This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by * it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or * the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version. * (at your option) any later version.
* *
* This program is distributed in the hope that it will be useful, * This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of * but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details. * GNU General Public License for more details.
* *
* You should have received a copy of the GNU General Public License * You should have received a copy of the GNU General Public License
* along with this program; if not see see <http://www.gnu.org/licenses/> * along with this program; if not see see <http://www.gnu.org/licenses/>
* *
*/ */
#ifdef SYS_getrandom #include "random_numbers.h"
#include <errno.h>
#endif
#include "n2n.h" // the following code offers an alterate pseudo random number generator
// namely XORSHIFT128+ to use instead of C's rand()
// its performance is on par with C's rand()
/* The following code offers an alterate pseudo random number generator // the state must be seeded in a way that it is not all zero, choose some
namely XORSHIFT128+ to use instead of C's rand(). Its performance is // arbitrary defaults (in this case: taken from splitmix64)
on par with C's rand(). static rn_generator_state_t rn_current_state = {
*/ .a = 0x9E3779B97F4A7C15,
.b = 0xBF58476D1CE4E5B9
};
/* The state must be seeded in a way that it is not all zero, choose some // used for mixing the initializing seed
arbitrary defaults (in this case: taken from splitmix64) */ static uint64_t splitmix64 (splitmix64_state_t *state) {
static struct rn_generator_state_t rn_current_state = {
.a = 0x9E3779B97F4A7C15,
.b = 0xBF58476D1CE4E5B9 };
/* used for mixing the initializing seed */ uint64_t result = state->s;
static uint64_t splitmix64 (struct splitmix64_state_t *state) {
uint64_t result = state->s; state->s = result + 0x9E3779B97F4A7C15;
state->s = result + 0x9E3779B97F4A7C15; result = (result ^ (result >> 30)) * 0xBF58476D1CE4E5B9;
result = (result ^ (result >> 27)) * 0x94D049BB133111EB;
result = (result ^ (result >> 30)) * 0xBF58476D1CE4E5B9; return result ^ (result >> 31);
result = (result ^ (result >> 27)) * 0x94D049BB133111EB;
return result ^ (result >> 31);
} }
int n2n_srand (uint64_t seed) { int n2n_srand (uint64_t seed) {
uint8_t i;
struct splitmix64_state_t smstate = {seed};
rn_current_state.a = 0;
rn_current_state.b = 0;
rn_current_state.a = splitmix64 (&smstate); uint8_t i;
rn_current_state.b = splitmix64 (&smstate); splitmix64_state_t smstate = { seed };
/* the following lines could be deleted as soon as it is formally prooved that rn_current_state.a = 0;
there is no seed leading to (a == b == 0). Until then, just to be safe: */ rn_current_state.b = 0;
if ( (rn_current_state.a == 0) && (rn_current_state.b == 0) ) {
rn_current_state.a = 0x9E3779B97F4A7C15;
rn_current_state.b = 0xBF58476D1CE4E5B9;
}
/* stabilize in unlikely case of weak state with only a few bits set */ rn_current_state.a = splitmix64 (&smstate);
for(i = 0; i < 32; i++) rn_current_state.b = splitmix64 (&smstate);
n2n_rand();
return 0; // the following lines could be deleted as soon as it is formally prooved th
} at
// there is no seed leading to (a == b == 0). until then, just to be safe:
if((rn_current_state.a == 0) && (rn_current_state.b == 0)) {
rn_current_state.a = 0x9E3779B97F4A7C15;
rn_current_state.b = 0xBF58476D1CE4E5B9;
}
/* The following code of xorshift128p was taken from // stabilize in unlikely case of weak state with only a few bits set
https://en.wikipedia.org/wiki/Xorshift as of July, 2019 for(i = 0; i < 32; i++)
and thus is considered public domain. */ n2n_rand();
uint64_t n2n_rand () {
uint64_t t = rn_current_state.a; return 0;
uint64_t const s = rn_current_state.b; }
rn_current_state.a = s; // the following code of xorshift128p was taken from
t ^= t << 23; // https://en.wikipedia.org/wiki/Xorshift as of July, 2019
t ^= t >> 17; // and thus is considered public domain
t ^= s ^ (s >> 26); uint64_t n2n_rand (void) {
rn_current_state.b = t;
uint64_t t = rn_current_state.a;
uint64_t const s = rn_current_state.b;
rn_current_state.a = s;
t ^= t << 23;
t ^= t >> 17;
t ^= s ^ (s >> 26);
rn_current_state.b = t;
return t + s; return t + s;
} }
/* The following code tries to gather some entropy from several sources // the following code tries to gather some entropy from several sources
for use as seed. Note, that this code does not set the random generator // for use as seed. Note, that this code does not set the random generator
state yet, a call to n2n_srand ( n2n_seed() ) would do. */ // state yet, a call to n2n_srand (n2n_seed()) would do
uint64_t n2n_seed (void) { uint64_t n2n_seed (void) {
uint64_t seed = 0; uint64_t seed = 0; /* this could even go uninitialized */
uint64_t ret = 0; uint64_t ret = 0; /* this could even go uninitialized */
size_t i; size_t i = 0;
#ifdef SYS_getrandom #ifdef SYS_getrandom
int rc = -1; int rc = -1;
for(i = 0; (i < RND_RETRIES) && (rc != sizeof(seed)); i++) { for(i = 0; (i < RND_RETRIES) && (rc != sizeof(seed)); i++) {
rc = syscall (SYS_getrandom, &seed, sizeof(seed), GRND_NONBLOCK); rc = syscall (SYS_getrandom, &seed, sizeof(seed), GRND_NONBLOCK);
// if successful, rc should contain the requested number of random bytes // if successful, rc should contain the requested number of random bytes
if(rc != sizeof(seed)) { if(rc != sizeof(seed)) {
if (errno != EAGAIN) { if (errno != EAGAIN) {
traceEvent(TRACE_ERROR, "n2n_seed faced error errno=%u from getrandom sy traceEvent(TRACE_ERROR, "n2n_seed faced error errno=%u from getr
scall.", errno); andom syscall.", errno);
break; break;
} }
} }
} }
// if we still see an EAGAIN error here, we must have run out of retries
if(errno == EAGAIN) { // if we still see an EAGAIN error here, we must have run out of retries
traceEvent(TRACE_ERROR, "n2n_seed saw getrandom syscall indicate not being a if(errno == EAGAIN) {
ble to provide enough entropy yet."); traceEvent(TRACE_ERROR, "n2n_seed saw getrandom syscall indicate not bei
} ng able to provide enough entropy yet.");
}
#endif #endif
// as we want randomness, it does no harm to add up even uninitialized values // as we want randomness, it does no harm to add up even uninitialized value
or s or
// erroneously arbitrary values returned from the syscall for the first time // erroneously arbitrary values returned from the syscall for the first time
ret += seed; ret += seed;
// __RDRND__ is set only if architecturual feature is set, e.g. compile with - march=native // __RDRND__ is set only if architecturual feature is set, e.g. compiled wit h -march=native
#ifdef __RDRND__ #ifdef __RDRND__
for(i = 0; i < RND_RETRIES; i++) { for(i = 0; i < RND_RETRIES; i++) {
if(_rdrand64_step ((unsigned long long*)&seed)) { if(_rdrand64_step((unsigned long long*)&seed)) {
// success! // success!
// from now on, we keep this inside the loop because in case of failure // from now on, we keep this inside the loop because in case of fail
// and with unchanged values, we do not want to double the previous value ure
ret += seed; // and with unchanged values, we do not want to double the previous
break; value
} ret += seed;
// continue loop to try again otherwise break;
} }
if(i == RND_RETRIES){ // continue loop to try again otherwise
traceEvent(TRACE_ERROR, "n2n_seed was not able to get a hardware generated r }
andom number from RDRND."); if(i == RND_RETRIES) {
} traceEvent(TRACE_ERROR, "n2n_seed was not able to get a hardware generat
ed random number from RDRND.");
}
#endif #endif
// __RDSEED__ ist set only if architecturual feature is set, e.g. compile with -march=native // __RDSEED__ ist set only if architecturual feature is set, e.g. compile wi th -march=native
#ifdef __RDSEED__ #ifdef __RDSEED__
for(i = 0; i < RND_RETRIES; i++) { #if __GNUC__ > 4
if(_rdseed64_step((unsigned long long*)&seed)) { for(i = 0; i < RND_RETRIES; i++) {
// success! if(_rdseed64_step((unsigned long long*)&seed)) {
ret += seed; // success!
break; ret += seed;
} break;
// continue loop to try again otherwise }
} // continue loop to try again otherwise
if(i == RND_RETRIES){ }
traceEvent(TRACE_ERROR, "n2n_seed was not able to get a hardware generated r if(i == RND_RETRIES) {
andom number from RDSEED."); traceEvent(TRACE_ERROR, "n2n_seed was not able to get a hardware generat
} ed random number from RDSEED.");
}
#endif
#endif #endif
/* The WIN32 code is still untested and thus commented #ifdef WIN32
#ifdef WIN32 HCRYPTPROV crypto_provider;
HCRYPTPROV crypto_provider; CryptAcquireContext (&crypto_provider, NULL, NULL,
CryptAcquireContext (&crypto_provider, NULL, (LPCWSTR)L"Microsoft Base Cryp PROV_RSA_FULL, CRYPT_VERIFYCONTEXT);
tographic Provider v1.0", CryptGenRandom (crypto_provider, 8, &seed);
PROV_RSA_FULL, CRYPT_VERIFYCONTEXT); CryptReleaseContext (crypto_provider, 0);
CryptGenRandom (crypto_provider, 8, &seed); ret += seed;
CryptReleaseContext (crypto_provider, 0); #endif
ret += seed;
#endif */ seed = time(NULL); /* UTC in seconds */
ret += seed;
seed = clock(); /* ticks since program start */
seed *= 18444244737;
ret += seed;
return ret;
}
// an integer squrare root approximation
// from https://stackoverflow.com/a/1100591
static int ftbl[33] = {
0, 1, 1, 2, 2, 4, 5, 8, 11, 16, 22, 32, 45, 64, 90,
128, 181 ,256 ,362, 512, 724, 1024, 1448, 2048, 2896,
4096, 5792, 8192, 11585, 16384, 23170, 32768, 46340 };
static int ftbl2[32] = {
32768, 33276, 33776, 34269, 34755, 35235, 35708, 36174,
36635, 37090, 37540, 37984, 38423, 38858, 39287, 39712,
40132, 40548, 40960, 41367, 41771, 42170, 42566, 42959,
43347, 43733, 44115, 44493, 44869, 45241, 45611, 45977 };
static int i_sqrt (int val) {
int cnt = 0;
int t = val;
while(t) {
cnt++;
t>>=1;
}
if(6 >= cnt)
t = (val << (6-cnt));
else
t = (val >> (cnt-6));
return (ftbl[cnt] * ftbl2[t & 31]) >> 15;
}
static int32_t int_sqrt (int val) {
int ret;
ret = i_sqrt (val);
ret += i_sqrt (val - ret * ret) / 16;
return ret;
}
seed = time(NULL); /* UTC in seconds */ // returns a random number from [0, max_n] with higher probability towards the b
ret += seed; orders
uint32_t n2n_rand_sqr (uint32_t max_n) {
seed = clock() * 18444244737; /* clock() = ticks since program start */ uint32_t raw_max = 0;
ret += seed; uint32_t raw_rnd = 0;
int32_t ret = 0;
raw_max = (max_n+2) * (max_n+2);
raw_rnd = n2n_rand() % (raw_max);
ret = int_sqrt(raw_rnd) / 2;
ret = (raw_rnd & 1) ? ret : -ret;
ret = max_n / 2 + ret;
if(ret < 0)
ret = 0;
if (ret > max_n)
ret = max_n;
return ret; return ret;
} }
 End of changes. 30 change blocks. 
122 lines changed or deleted 188 lines changed or added

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