From 0e5b2871ca6456b01d4bf037a6e68badf1ff1a41 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Henryk=20Pl=C3=B6tz?= Date: Fri, 3 Oct 2014 19:58:52 +0200 Subject: Initial commit of djbdns-1.05.tar.gz Source was http://cr.yp.to/djbdns/djbdns-1.05.tar.gz, SHA1 2efdb3a039d0c548f40936aa9cb30829e0ce8c3d --- dns_random.c | 63 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 63 insertions(+) create mode 100644 dns_random.c (limited to 'dns_random.c') diff --git a/dns_random.c b/dns_random.c new file mode 100644 index 0000000..2158ed4 --- /dev/null +++ b/dns_random.c @@ -0,0 +1,63 @@ +#include +#include "dns.h" +#include "taia.h" +#include "uint32.h" + +static uint32 seed[32]; +static uint32 in[12]; +static uint32 out[8]; +static int outleft = 0; + +#define ROTATE(x,b) (((x) << (b)) | ((x) >> (32 - (b)))) +#define MUSH(i,b) x = t[i] += (((x ^ seed[i]) + sum) ^ ROTATE(x,b)); + +static void surf(void) +{ + uint32 t[12]; uint32 x; uint32 sum = 0; + int r; int i; int loop; + + for (i = 0;i < 12;++i) t[i] = in[i] ^ seed[12 + i]; + for (i = 0;i < 8;++i) out[i] = seed[24 + i]; + x = t[11]; + for (loop = 0;loop < 2;++loop) { + for (r = 0;r < 16;++r) { + sum += 0x9e3779b9; + MUSH(0,5) MUSH(1,7) MUSH(2,9) MUSH(3,13) + MUSH(4,5) MUSH(5,7) MUSH(6,9) MUSH(7,13) + MUSH(8,5) MUSH(9,7) MUSH(10,9) MUSH(11,13) + } + for (i = 0;i < 8;++i) out[i] ^= t[i + 4]; + } +} + +void dns_random_init(const char data[128]) +{ + int i; + struct taia t; + char tpack[16]; + + for (i = 0;i < 32;++i) + uint32_unpack(data + 4 * i,seed + i); + + taia_now(&t); + taia_pack(tpack,&t); + for (i = 0;i < 4;++i) + uint32_unpack(tpack + 4 * i,in + 4 + i); + + in[8] = getpid(); + in[9] = getppid(); + /* more space in 10 and 11, but this is probably enough */ +} + +unsigned int dns_random(unsigned int n) +{ + if (!n) return 0; + + if (!outleft) { + if (!++in[0]) if (!++in[1]) if (!++in[2]) ++in[3]; + surf(); + outleft = 8; + } + + return out[--outleft] % n; +} -- cgit v1.2.3