Index: sys/netinet6/ip6_id.c
===================================================================
--- sys/netinet6/ip6_id.c
+++ sys/netinet6/ip6_id.c
@@ -89,9 +89,12 @@
 #include <sys/types.h>
 #include <sys/param.h>
 #include <sys/kernel.h>
+#include <sys/random.h>
 #include <sys/socket.h>
 #include <sys/libkern.h>
 
+#include <machine/cpu.h>
+
 #include <net/if.h>
 #include <net/route.h>
 #include <net/vnet.h>
@@ -171,6 +174,25 @@
 	return (s);
 }
 
+static inline uint32_t
+arc4random_wrapper(void)
+{
+	/*
+	 * Is it sane to generate potentially non-random IPv6 flowids if random
+	 * isn't seeded yet, rather than blocking indefinitely?  Or do IPv6
+	 * flowids really need to be unpredictable (and would prefer to block
+	 * indefinitely until entropy is available)?
+	 */
+
+	if (!is_random_seeded()) {
+		uint64_t cc;
+
+		cc = get_cyclecount();
+		return ((cc >> 32) ^ cc);
+	}
+	return (arc4random());
+}
+
 /*
  * Initializes the seed and chooses a suitable generator. Also toggles
  * the msb flag. The msb flag is used to generate two distinct
@@ -185,20 +207,20 @@
 	u_int32_t j, i;
 	int noprime = 1;
 
-	p->ru_x = arc4random() % p->ru_m;
+	p->ru_x = arc4random_wrapper() % p->ru_m;
 
 	/* (bits - 1) bits of random seed */
-	p->ru_seed = arc4random() & (~0U >> (32 - p->ru_bits + 1));
-	p->ru_seed2 = arc4random() & (~0U >> (32 - p->ru_bits + 1));
+	p->ru_seed = arc4random_wrapper() & (~0U >> (32 - p->ru_bits + 1));
+	p->ru_seed2 = arc4random_wrapper() & (~0U >> (32 - p->ru_bits + 1));
 
 	/* Determine the LCG we use */
-	p->ru_b = (arc4random() & (~0U >> (32 - p->ru_bits))) | 1;
+	p->ru_b = (arc4random_wrapper() & (~0U >> (32 - p->ru_bits))) | 1;
 	p->ru_a = pmod(p->ru_agen,
-	    (arc4random() & (~0U >> (32 - p->ru_bits))) & (~1U), p->ru_m);
+	    (arc4random_wrapper() & (~0U >> (32 - p->ru_bits))) & (~1U), p->ru_m);
 	while (p->ru_b % 3 == 0)
 		p->ru_b += 2;
 
-	j = arc4random() % p->ru_n;
+	j = arc4random_wrapper() % p->ru_n;
 
 	/*
 	 * Do a fast gcd(j, RU_N - 1), so we can find a j with
@@ -232,7 +254,7 @@
 		initid(p);
 
 	/* Skip a random number of ids */
-	n = arc4random() & 0x3;
+	n = arc4random_wrapper() & 0x3;
 	if (p->ru_counter + n >= p->ru_max)
 		initid(p);