xnu-7195.101.1.tar.gz

[apple/xnu.git] / bsd / netinet6 / ip6_id.c

diff --git a/bsd/netinet6/ip6_id.c b/bsd/netinet6/ip6_id.c
index eab70a6c01ea63dfa6fad8e0ca11a47e78dac967..24780a44637018418cb1f2a1ae69bed0c49cc09a 100644 (file)
--- a/bsd/netinet6/ip6_id.c
+++ b/bsd/netinet6/ip6_id.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2009-2013 Apple Inc. All rights reserved.
+ * Copyright (c) 2009-2019 Apple Inc. All rights reserved.
  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  *
@@ -129,14 +129,14 @@
 #include <netinet6/ip6_var.h>
 
 struct randomtab {
-       const int       ru_bits; /* resulting bits */
-       const long      ru_out; /* Time after wich will be reseeded */
-       const u_int32_t ru_max; /* Uniq cycle, avoid blackjack prediction */
-       const u_int32_t ru_gen; /* Starting generator */
-       const u_int32_t ru_n;   /* ru_n: prime, ru_n - 1: product of pfacts[] */
+       const int       ru_bits; /* resulting bits */
+       const long      ru_out; /* Time after wich will be reseeded */
+       const u_int32_t ru_max; /* Uniq cycle, avoid blackjack prediction */
+       const u_int32_t ru_gen; /* Starting generator */
+       const u_int32_t ru_n;   /* ru_n: prime, ru_n - 1: product of pfacts[] */
        const u_int32_t ru_agen; /* determine ru_a as ru_agen^(2*rand) */
-       const u_int32_t ru_m;   /* ru_m = 2^x*3^y */
-       const u_int32_t pfacts[4];      /* factors of ru_n */
+       const u_int32_t ru_m;   /* ru_m = 2^x*3^y */
+       const u_int32_t pfacts[4];      /* factors of ru_n */
 
        u_int32_t ru_counter;
        u_int32_t ru_msb;
@@ -149,27 +149,23 @@ struct randomtab {
 };
 
 static struct randomtab randomtab_32 = {
-       32,                     /* resulting bits */
-       180,                    /* Time after wich will be reseeded */
-       1000000000,             /* Uniq cycle, avoid blackjack prediction */
-       2,                      /* Starting generator */
-       2147483629,             /* RU_N-1 = 2^2*3^2*59652323 */
-       7,                      /* determine ru_a as RU_AGEN^(2*rand) */
-       1836660096,             /* RU_M = 2^7*3^15 - don't change */
-       { 2, 3, 59652323, 0 },  /* factors of ru_n */
-       0, 0, 0, 0, 0, 0, 0, 0, 0
-};
-
-static struct randomtab randomtab_20 = {
-       20,                     /* resulting bits */
-       180,                    /* Time after wich will be reseeded */
-       200000,                 /* Uniq cycle, avoid blackjack prediction */
-       2,                      /* Starting generator */
-       524269,                 /* RU_N-1 = 2^2*3^2*14563 */
-       7,                      /* determine ru_a as RU_AGEN^(2*rand) */
-       279936,                 /* RU_M = 2^7*3^7 - don't change */
-       { 2, 3, 14563, 0 },     /* factors of ru_n */
-       0, 0, 0, 0, 0, 0, 0, 0, 0
+       .ru_bits = 32,          /* resulting bits */
+       .ru_out = 180,          /* Time after wich will be reseeded */
+       .ru_max = 1000000000,   /* Uniq cycle, avoid blackjack prediction */
+       .ru_gen = 2,            /* Starting generator */
+       .ru_n = 2147483629,     /* RU_N-1 = 2^2*3^2*59652323 */
+       .ru_agen = 7,           /* determine ru_a as RU_AGEN^(2*rand) */
+       .ru_m = 1836660096,     /* RU_M = 2^7*3^15 - don't change */
+       .pfacts = { 2, 3, 59652323, 0 },        /* factors of ru_n */
+       .ru_counter = 0,
+       .ru_msb = 0,
+       .ru_x = 0,
+       .ru_seed = 0,
+       .ru_seed2 = 0,
+       .ru_a = 0,
+       .ru_b = 0,
+       .ru_g = 0,
+       .ru_reseed = 0
 };
 
 static u_int32_t pmod(u_int32_t, u_int32_t, u_int32_t);
@@ -190,12 +186,13 @@ pmod(u_int32_t gen, u_int32_t expo, u_int32_t mod)
        u = expo;
 
        while (u) {
-               if (u & 1)
+               if (u & 1) {
                        s = (s * t) % mod;
+               }
                u >>= 1;
                t = (t * t) % mod;
        }
-       return (s);
+       return (u_int32_t)s;
 }
 
 /*
@@ -223,8 +220,9 @@ initid(struct randomtab *p)
        p->ru_b = (RandomULong() & (~0U >> (32 - p->ru_bits))) | 1;
        p->ru_a = pmod(p->ru_agen,
            (RandomULong() & (~0U >> (32 - p->ru_bits))) & (~1U), p->ru_m);
-       while (p->ru_b % 3 == 0)
+       while (p->ru_b % 3 == 0) {
                p->ru_b += 2;
+       }
 
        j = RandomULong() % p->ru_n;
 
@@ -234,14 +232,17 @@ initid(struct randomtab *p)
         * RU_GEN^j mod RU_N
         */
        while (noprime) {
-               for (i = 0; p->pfacts[i] > 0; i++)
-                       if (j % p->pfacts[i] == 0)
+               for (i = 0; p->pfacts[i] > 0; i++) {
+                       if (j % p->pfacts[i] == 0) {
                                break;
+                       }
+               }
 
-               if (p->pfacts[i] == 0)
+               if (p->pfacts[i] == 0) {
                        noprime = 0;
-               else
+               } else {
                        j = (j + 1) % p->ru_n;
+               }
        }
 
        p->ru_g = pmod(p->ru_gen, j, p->ru_n);
@@ -258,15 +259,17 @@ randomid(struct randomtab *p)
        int i, n;
        u_int32_t tmp;
 
-       if (p->ru_counter >= p->ru_max || curtime > p->ru_reseed)
+       if (p->ru_counter >= p->ru_max || curtime > p->ru_reseed) {
                initid(p);
+       }
 
        tmp = RandomULong();
 
        /* Skip a random number of ids */
        n = tmp & 0x3; tmp = tmp >> 2;
-       if (p->ru_counter + n >= p->ru_max)
+       if (p->ru_counter + n >= p->ru_max) {
                initid(p);
+       }
 
        for (i = 0; i <= n; i++) {
                /* Linear Congruential Generator */
@@ -275,20 +278,18 @@ randomid(struct randomtab *p)
 
        p->ru_counter += i;
 
-       return ((p->ru_seed ^ pmod(p->ru_g, p->ru_seed2 ^ p->ru_x, p->ru_n)) |
-           p->ru_msb);
+       return (p->ru_seed ^ pmod(p->ru_g, p->ru_seed2 ^ p->ru_x, p->ru_n)) |
+              p->ru_msb;
 }
 
 u_int32_t
 ip6_randomid(void)
 {
-
-       return (randomid(&randomtab_32));
+       return randomid(&randomtab_32);
 }
 
 u_int32_t
 ip6_randomflowlabel(void)
 {
-
-       return (randomid(&randomtab_20) & 0xfffff);
+       return RandomULong() & IPV6_FLOWLABEL_MASK;
 }