kernel: massive pci code rewrite

[plan9front.git] / sys / src / 9 / port / random.c

diff --git a/sys/src/9/port/random.c b/sys/src/9/port/random.c
index d401e7e0181eccbe1f7a58b099cdbb64402f2c7c..b27e5720dbd9c427f17ec62075c9ad8e7e9f4416 100644 (file)
--- a/sys/src/9/port/random.c
+++ b/sys/src/9/port/random.c
@@ -89,7 +89,6 @@ ulong
 randomread(void *p, ulong n)
 {
        Chachastate c;
-       ulong b;
 
        if(n == 0)
                return 0;
@@ -97,12 +96,13 @@ randomread(void *p, ulong n)
        if(hwrandbuf != nil)
                (*hwrandbuf)(p, n);
 
-       /* copy chacha state and advance block counter */
+       /* copy chacha state, rekey and increment iv */
        qlock(rs);
        c = *rs;
-       b = rs->input[12];
-       rs->input[12] += (n + ChachaBsize-1)/ChachaBsize;
-       if(rs->input[12] < b) rs->input[13]++;
+       chacha_encrypt((uchar*)&rs->input[4], 32, &c);
+       if(++rs->input[13] == 0)
+               if(++rs->input[14] == 0)
+                       ++rs->input[15];
        qunlock(rs);
 
        /* encrypt the buffer, can fault */
@@ -120,3 +120,28 @@ genrandom(uchar *p, int n)
 {
        randomread(p, n);
 }
+
+/* used by rand(),nrand() */
+long
+lrand(void)
+{
+       /* xoroshiro128+ algorithm */
+       static int seeded = 0;
+       static uvlong s[2];
+       static Lock lk;
+       ulong r;
+
+       if(seeded == 0){
+               randomread(s, sizeof(s));
+               seeded = (s[0] | s[1]) != 0;
+       }
+
+       lock(&lk);
+       r = (s[0] + s[1]) >> 33;
+       s[1] ^= s[0];
+       s[0] = (s[0] << 55 | s[0] >> 9) ^ s[1] ^ (s[1] << 14);
+       s[1] = (s[1] << 36 | s[1] >> 28);
+       unlock(&lk);
+
+       return r;
+}