- __u32 a = buf[0], b = buf[1], c = buf[2], d = buf[3];
-
- /* Round 1 */
- ROUND(F, a, b, c, d, in[ 0] + K1, 3);
- ROUND(F, d, a, b, c, in[ 1] + K1, 7);
- ROUND(F, c, d, a, b, in[ 2] + K1, 11);
- ROUND(F, b, c, d, a, in[ 3] + K1, 19);
- ROUND(F, a, b, c, d, in[ 4] + K1, 3);
- ROUND(F, d, a, b, c, in[ 5] + K1, 7);
- ROUND(F, c, d, a, b, in[ 6] + K1, 11);
- ROUND(F, b, c, d, a, in[ 7] + K1, 19);
- ROUND(F, a, b, c, d, in[ 8] + K1, 3);
- ROUND(F, d, a, b, c, in[ 9] + K1, 7);
- ROUND(F, c, d, a, b, in[10] + K1, 11);
- ROUND(F, b, c, d, a, in[11] + K1, 19);
-
- /* Round 2 */
- ROUND(G, a, b, c, d, in[ 1] + K2, 3);
- ROUND(G, d, a, b, c, in[ 3] + K2, 5);
- ROUND(G, c, d, a, b, in[ 5] + K2, 9);
- ROUND(G, b, c, d, a, in[ 7] + K2, 13);
- ROUND(G, a, b, c, d, in[ 9] + K2, 3);
- ROUND(G, d, a, b, c, in[11] + K2, 5);
- ROUND(G, c, d, a, b, in[ 0] + K2, 9);
- ROUND(G, b, c, d, a, in[ 2] + K2, 13);
- ROUND(G, a, b, c, d, in[ 4] + K2, 3);
- ROUND(G, d, a, b, c, in[ 6] + K2, 5);
- ROUND(G, c, d, a, b, in[ 8] + K2, 9);
- ROUND(G, b, c, d, a, in[10] + K2, 13);
-
- /* Round 3 */
- ROUND(H, a, b, c, d, in[ 3] + K3, 3);
- ROUND(H, d, a, b, c, in[ 7] + K3, 9);
- ROUND(H, c, d, a, b, in[11] + K3, 11);
- ROUND(H, b, c, d, a, in[ 2] + K3, 15);
- ROUND(H, a, b, c, d, in[ 6] + K3, 3);
- ROUND(H, d, a, b, c, in[10] + K3, 9);
- ROUND(H, c, d, a, b, in[ 1] + K3, 11);
- ROUND(H, b, c, d, a, in[ 5] + K3, 15);
- ROUND(H, a, b, c, d, in[ 9] + K3, 3);
- ROUND(H, d, a, b, c, in[ 0] + K3, 9);
- ROUND(H, c, d, a, b, in[ 4] + K3, 11);
- ROUND(H, b, c, d, a, in[ 8] + K3, 15);
-
- return buf[1] + b; /* "most hashed" word */
- /* Alternative: return sum of all words? */
-}
-#endif
-
-#undef ROUND
-#undef F
-#undef G
-#undef H
-#undef K1
-#undef K2
-#undef K3
-
-/* This should not be decreased so low that ISNs wrap too fast. */
-#define REKEY_INTERVAL (300 * HZ)
-/*
- * Bit layout of the tcp sequence numbers (before adding current time):
- * bit 24-31: increased after every key exchange
- * bit 0-23: hash(source,dest)
- *
- * The implementation is similar to the algorithm described
- * in the Appendix of RFC 1185, except that
- * - it uses a 1 MHz clock instead of a 250 kHz clock
- * - it performs a rekey every 5 minutes, which is equivalent
- * to a (source,dest) tulple dependent forward jump of the
- * clock by 0..2^(HASH_BITS+1)
- *
- * Thus the average ISN wraparound time is 68 minutes instead of
- * 4.55 hours.
- *
- * SMP cleanup and lock avoidance with poor man's RCU.
- * Manfred Spraul <manfred@colorfullife.com>
- *
- */
-#define COUNT_BITS 8
-#define COUNT_MASK ((1 << COUNT_BITS) - 1)
-#define HASH_BITS 24
-#define HASH_MASK ((1 << HASH_BITS) - 1)
-
-static struct keydata {
- __u32 count; /* already shifted to the final position */
- __u32 secret[12];
-} ____cacheline_aligned ip_keydata[2];
-
-static unsigned int ip_cnt;
-
-static void rekey_seq_generator(struct work_struct *work);
-
-static DECLARE_DELAYED_WORK(rekey_work, rekey_seq_generator);
-
-/*
- * Lock avoidance:
- * The ISN generation runs lockless - it's just a hash over random data.
- * State changes happen every 5 minutes when the random key is replaced.
- * Synchronization is performed by having two copies of the hash function
- * state and rekey_seq_generator always updates the inactive copy.
- * The copy is then activated by updating ip_cnt.
- * The implementation breaks down if someone blocks the thread
- * that processes SYN requests for more than 5 minutes. Should never
- * happen, and even if that happens only a not perfectly compliant
- * ISN is generated, nothing fatal.
- */
-static void rekey_seq_generator(struct work_struct *work)
-{
- struct keydata *keyptr = &ip_keydata[1 ^ (ip_cnt & 1)];
-
- get_random_bytes(keyptr->secret, sizeof(keyptr->secret));
- keyptr->count = (ip_cnt & COUNT_MASK) << HASH_BITS;
- smp_wmb();
- ip_cnt++;
- schedule_delayed_work(&rekey_work,
- round_jiffies_relative(REKEY_INTERVAL));
-}
-
-static inline struct keydata *get_keyptr(void)
-{
- struct keydata *keyptr = &ip_keydata[ip_cnt & 1];
-
- smp_rmb();
-
- return keyptr;
-}
-
-static __init int seqgen_init(void)
-{
- rekey_seq_generator(NULL);