crypto/siphash: new module.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

Makefile-ccan

@@ -43,6 +43,7 @@ MODS := a_star \
 	crypto/ripemd160 \
 	crypto/sha256 \
 	crypto/shachain \
+	crypto/siphash24 \
 	daemonize \
 	daemon_with_notify \
 	darray \

ccan/crypto/siphash24/LICENSE

+../../../licenses/CC0
\ No newline at end of file

ccan/crypto/siphash24/_info

+#include "config.h"
+#include <stdio.h>
+#include <string.h>
+
+/**
+ * crypto/siphash24 - implementation of SipHash-2-4.
+ *
+ * SipHash was designed as a mitigation to hash-flooding DoS
+ * attacks. It is now used in the hash tables implementation of
+ * Python, Ruby, Perl 5, etc.
+ *
+ * SipHash was designed by Jean-Philippe Aumasson and Daniel J. Bernstein. 
+ *
+ * License: CC0
+ * Maintainer: Rusty Russell <rusty@rustcorp.com.au>
+ *
+ * Example:
+ * // Dumb example to print siphash of words, and all strung together.
+ * #include <ccan/crypto/siphash24/siphash24.h>
+ * #include <stdio.h>
+ * #include <stdlib.h>
+ * #include <string.h>
+ * #include <inttypes.h>
+ *
+ * int main(int argc, char *argv[])
+ * {
+ *	struct siphash_seed seed;
+ *	struct siphash24_ctx ctx;
+ *	int i;
+ *
+ *	if (argc < 3) {
+ *		fprintf(stderr, "Need at least seed1 and seed2 arguments");
+ *		exit(1);
+ *	}
+ *
+ *	seed.u.u64[0] = atoi(argv[1]);
+ *	seed.u.u64[1] = atoi(argv[2]);
+ *	siphash24_init(&ctx, &seed);
+ *	for (i = 3; i < argc; i++) {
+ *		printf("Hash of '%s' = %"PRIu64,
+ *			argv[i], siphash24(&seed, argv[i], strlen(argv[i])));
+ *		siphash24_update(&ctx, argv[i], strlen(argv[i]));
+ *	}
+ *	printf("Hash of concatenated args = %"PRIu64, siphash24_done(&ctx));
+ *	return 0;
+ * }
+ */
+int main(int argc, char *argv[])
+{
+	/* Expect exactly one argument */
+	if (argc != 2)
+		return 1;
+
+	if (strcmp(argv[1], "depends") == 0) {
+		printf("ccan/endian\n");
+		return 0;
+	}
+
+	return 1;
+}

ccan/crypto/siphash24/siphash24.c

+/* CC0 license (public domain) - see LICENSE file for details */
+/* Based on CC0 reference implementation:
+ * https://github.com/veorq/SipHash c03e6bbf6613243bc30788912ad4afbc0b992d47
+ */
+#include <ccan/crypto/siphash24/siphash24.h>
+#include <ccan/endian/endian.h>
+#include <stdbool.h>
+#include <assert.h>
+#include <string.h>
+
+/* default: SipHash-2-4 */
+#define cROUNDS 2
+#define dROUNDS 4
+
+#define ROTL(x, b) (uint64_t)(((x) << (b)) | ((x) >> (64 - (b))))
+
+#define SIPROUND(v)							\
+	do {								\
+		v[0] += v[1];						\
+		v[1] = ROTL(v[1], 13);					\
+		v[1] ^= v[0];						\
+		v[0] = ROTL(v[0], 32);					\
+		v[2] += v[3];						\
+		v[3] = ROTL(v[3], 16);					\
+		v[3] ^= v[2];						\
+		v[0] += v[3];						\
+		v[3] = ROTL(v[3], 21);					\
+		v[3] ^= v[0];						\
+		v[2] += v[1];						\
+		v[1] = ROTL(v[1], 17);					\
+		v[1] ^= v[2];						\
+		v[2] = ROTL(v[2], 32);					\
+	} while (0)
+
+static void invalidate_siphash24(struct siphash24_ctx *ctx)
+{
+	ctx->bytes = -1ULL;
+}
+
+static void check_siphash24(struct siphash24_ctx *ctx)
+{
+	assert(ctx->bytes != -1ULL);
+}
+
+static bool alignment_ok(const void *p, size_t n)
+{
+#if HAVE_UNALIGNED_ACCESS
+	return true;
+#else
+	return ((size_t)p % n == 0);
+#endif
+}
+
+static void add_64bits(uint64_t v[4], uint64_t in)
+{
+	int i;
+	uint64_t m = cpu_to_le64(in);
+	v[3] ^= m;
+
+	for (i = 0; i < cROUNDS; ++i)
+		SIPROUND(v);
+
+	v[0] ^= m;
+}
+
+static void add(struct siphash24_ctx *ctx, const void *p, size_t len)
+{
+	const unsigned char *data = p;
+	size_t bufsize = ctx->bytes % sizeof(ctx->buf.u8);
+
+	if (bufsize + len >= sizeof(ctx->buf.u8)) {
+		// Fill the buffer, and process it.
+		memcpy(ctx->buf.u8 + bufsize, data,
+		       sizeof(ctx->buf.u8) - bufsize);
+		ctx->bytes += sizeof(ctx->buf.u8) - bufsize;
+		data += sizeof(ctx->buf.u8) - bufsize;
+		len -= sizeof(ctx->buf.u8) - bufsize;
+		add_64bits(ctx->v, ctx->buf.u64);
+		bufsize = 0;
+	}
+
+	while (len >= sizeof(ctx->buf.u8)) {
+		// Process full chunks directly from the source.
+		if (alignment_ok(data, sizeof(uint64_t)))
+			add_64bits(ctx->v, *(const uint64_t *)data);
+		else {
+			memcpy(ctx->buf.u8, data, sizeof(ctx->buf));
+			add_64bits(ctx->v, ctx->buf.u64);
+		}
+		ctx->bytes += sizeof(ctx->buf.u8);
+		data += sizeof(ctx->buf.u8);
+		len -= sizeof(ctx->buf.u8);
+	}
+	    
+	if (len) {
+		// Fill the buffer with what remains.
+		memcpy(ctx->buf.u8 + bufsize, data, len);
+		ctx->bytes += len;
+	}
+}
+
+void siphash24_init(struct siphash24_ctx *ctx, const struct siphash_seed *seed)
+{
+	struct siphash24_ctx init = SIPHASH24_INIT(0, 0);
+	*ctx = init;
+	ctx->v[0] ^= seed->u.u64[0];
+	ctx->v[1] ^= seed->u.u64[1];
+	ctx->v[2] ^= seed->u.u64[0];
+	ctx->v[3] ^= seed->u.u64[1];
+}
+
+void siphash24_update(struct siphash24_ctx *ctx, const void *p, size_t size)
+{
+	check_siphash24(ctx);
+	add(ctx, p, size);
+}
+
+uint64_t siphash24_done(struct siphash24_ctx *ctx)
+{
+	uint64_t b;
+	int i;
+
+	b = ctx->bytes << 56;
+
+	switch (ctx->bytes % 8) {
+	case 7:
+		b |= ((uint64_t)ctx->buf.u8[6]) << 48;
+	case 6:
+		b |= ((uint64_t)ctx->buf.u8[5]) << 40;
+	case 5:
+		b |= ((uint64_t)ctx->buf.u8[4]) << 32;
+	case 4:
+		b |= ((uint64_t)ctx->buf.u8[3]) << 24;
+	case 3:
+		b |= ((uint64_t)ctx->buf.u8[2]) << 16;
+	case 2:
+		b |= ((uint64_t)ctx->buf.u8[1]) << 8;
+	case 1:
+		b |= ((uint64_t)ctx->buf.u8[0]);
+		break;
+	case 0:
+		break;
+	}
+
+	ctx->v[3] ^= b;
+
+	for (i = 0; i < cROUNDS; ++i)
+		SIPROUND(ctx->v);
+
+	ctx->v[0] ^= b;
+
+	ctx->v[2] ^= 0xff;
+
+	for (i = 0; i < dROUNDS; ++i)
+		SIPROUND(ctx->v);
+
+	b = ctx->v[0] ^ ctx->v[1] ^ ctx->v[2] ^ ctx->v[3];
+
+	invalidate_siphash24(ctx);
+	return cpu_to_le64(b);
+}
+
+uint64_t siphash24(const struct siphash_seed *seed, const void *p, size_t size)
+{
+	struct siphash24_ctx ctx;
+
+	siphash24_init(&ctx, seed);
+	siphash24_update(&ctx, p, size);
+	return siphash24_done(&ctx);
+}
+	
+void siphash24_u8(struct siphash24_ctx *ctx, uint8_t v)
+{
+	siphash24_update(ctx, &v, sizeof(v));
+}
+
+void siphash24_u16(struct siphash24_ctx *ctx, uint16_t v)
+{
+	siphash24_update(ctx, &v, sizeof(v));
+}
+
+void siphash24_u32(struct siphash24_ctx *ctx, uint32_t v)
+{
+	siphash24_update(ctx, &v, sizeof(v));
+}
+
+void siphash24_u64(struct siphash24_ctx *ctx, uint64_t v)
+{
+	siphash24_update(ctx, &v, sizeof(v));
+}
+
+/* Add as little-endian */
+void siphash24_le16(struct siphash24_ctx *ctx, uint16_t v)
+{
+	leint16_t lev = cpu_to_le16(v);
+	siphash24_update(ctx, &lev, sizeof(lev));
+}
+	
+void siphash24_le32(struct siphash24_ctx *ctx, uint32_t v)
+{
+	leint32_t lev = cpu_to_le32(v);
+	siphash24_update(ctx, &lev, sizeof(lev));
+}
+	
+void siphash24_le64(struct siphash24_ctx *ctx, uint64_t v)
+{
+	leint64_t lev = cpu_to_le64(v);
+	siphash24_update(ctx, &lev, sizeof(lev));
+}
+
+/* Add as big-endian */
+void siphash24_be16(struct siphash24_ctx *ctx, uint16_t v)
+{
+	beint16_t bev = cpu_to_be16(v);
+	siphash24_update(ctx, &bev, sizeof(bev));
+}
+	
+void siphash24_be32(struct siphash24_ctx *ctx, uint32_t v)
+{
+	beint32_t bev = cpu_to_be32(v);
+	siphash24_update(ctx, &bev, sizeof(bev));
+}
+	
+void siphash24_be64(struct siphash24_ctx *ctx, uint64_t v)
+{
+	beint64_t bev = cpu_to_be64(v);
+	siphash24_update(ctx, &bev, sizeof(bev));
+}

ccan/crypto/siphash24/siphash24.h

+/* CC0 license (public domain) - see LICENSE file for details */
+#ifndef CCAN_CRYPTO_SIPHASH24_H
+#define CCAN_CRYPTO_SIPHASH24_H
+/* Public domain - see LICENSE file for details */
+#include "config.h"
+#include <stdint.h>
+#include <stdlib.h>
+
+/**
+ * struct siphash_seed - random bytes to seed the siphash
+ * @u.u8: an unsigned char array.
+ * @u.u32: a 32-bit integer array.
+ *
+ * Other fields may be added to the union in future.
+ */
+struct siphash_seed {
+	union {
+		/* Array of chars */
+		unsigned char u8[16];
+		/* Array of uint32_t */
+		uint32_t u32[4];
+		/* Array of uint64_t */
+		uint64_t u64[2];
+	} u;
+};
+
+/**
+ * siphash24 - return SipHash-2-4 of an object.
+ * @seed: the seed for the hash.
+ * @p: pointer to memory,
+ * @size: the number of bytes pointed to by @p
+ *
+ * The bytes pointed to by @p is SIPHASH24 hashed into @siphash24,
+ * using seed @seed.  This is equivalent to siphash24_init(),
+ * siphash24_update() then siphash24_done().
+ */
+uint64_t siphash24(const struct siphash_seed *seed, const void *p, size_t size);
+
+/**
+ * struct siphash24_ctx - structure to store running context for siphash24
+ */
+struct siphash24_ctx {
+	uint64_t v[4];
+	uint64_t bytes;
+	union {
+		uint64_t u64;
+		unsigned char u8[8];
+	} buf;
+};
+
+/**
+ * siphash24_init - initialize an SIPHASH24 context.
+ * @ctx: the siphash24_ctx to initialize
+ * @seed: the siphash_seed.
+ *
+ * This must be called before siphash24_update or siphash24_done, or
+ * alternately you can assign SIPHASH24_INIT.
+ *
+ * If it was already initialized, this forgets anything which was
+ * hashed before.
+ *
+ * Example:
+ * static void hash_all(const char **arr, uint64_t *hash)
+ * {
+ *	size_t i;
+ *	struct siphash24_ctx ctx;
+ *	struct siphash_seed seed;
+ *
+ *	// Use a random seed, not this!
+ *	memset(seed.u.u64, 7, sizeof(seed.u.u64));
+ *	siphash24_init(&ctx, &seed);
+ *	for (i = 0; arr[i]; i++)
+ *		siphash24_update(&ctx, arr[i], strlen(arr[i]));
+ *	*hash = siphash24_done(&ctx);
+ * }
+ */
+void siphash24_init(struct siphash24_ctx *ctx, const struct siphash_seed *seed);
+
+/**
+ * SIPHASH24_INIT - initializer for an SIPHASH24 context.
+ * @seed1, @seed2: two 64-bit words for seed.
+ *
+ * This can be used to staticly initialize an SIPHASH24 context (instead
+ * of siphash24_init()).
+ *
+ * Example:
+ * static uint64_t hash_all(const char **arr)
+ * {
+ *	size_t i;
+ *	struct siphash24_ctx ctx = SIPHASH24_INIT(0x0707070707070707ULL,
+ *						  0x0707070707070707ULL);
+ *
+ *	for (i = 0; arr[i]; i++)
+ *		siphash24_update(&ctx, arr[i], strlen(arr[i]));
+ *	return siphash24_done(&ctx);
+ * }
+ */
+#define SIPHASH24_INIT(seed1, seed2)		\
+	{ { 0x736f6d6570736575ULL ^ (seed1),	\
+	    0x646f72616e646f6dULL ^ (seed2),	\
+	    0x6c7967656e657261ULL ^ (seed1),	\
+	    0x7465646279746573ULL ^ (seed2) } }
+
+/**
+ * siphash24_update - include some memory in the hash.
+ * @ctx: the siphash24_ctx to use
+ * @p: pointer to memory,
+ * @size: the number of bytes pointed to by @p
+ *
+ * You can call this multiple times to hash more data, before calling
+ * siphash24_done().
+ */
+void siphash24_update(struct siphash24_ctx *ctx, const void *p, size_t size);
+
+/**
+ * siphash24_done - finish SIPHASH24 and return the hash
+ * @ctx: the siphash24_ctx to complete
+ *
+ * Note that @ctx is *destroyed* by this, and must be reinitialized.
+ * To avoid that, pass a copy instead.
+ */
+uint64_t siphash24_done(struct siphash24_ctx *siphash24);
+
+/* Add various types to an SIPHASH24 hash */
+void siphash24_u8(struct siphash24_ctx *ctx, uint8_t v);
+void siphash24_u16(struct siphash24_ctx *ctx, uint16_t v);
+void siphash24_u32(struct siphash24_ctx *ctx, uint32_t v);
+void siphash24_u64(struct siphash24_ctx *ctx, uint64_t v);
+
+/* Add as little-endian */
+void siphash24_le16(struct siphash24_ctx *ctx, uint16_t v);
+void siphash24_le32(struct siphash24_ctx *ctx, uint32_t v);
+void siphash24_le64(struct siphash24_ctx *ctx, uint64_t v);
+
+/* Add as big-endian */
+void siphash24_be16(struct siphash24_ctx *ctx, uint16_t v);
+void siphash24_be32(struct siphash24_ctx *ctx, uint32_t v);
+void siphash24_be64(struct siphash24_ctx *ctx, uint64_t v);
+#endif /* CCAN_CRYPTO_SIPHASH24_H */

ccan/crypto/siphash24/test/run.c

+#include <ccan/crypto/siphash24/siphash24.h>
+/* Include the C files directly. */
+#include <ccan/crypto/siphash24/siphash24.c>
+#include <ccan/tap/tap.h>
+
+/* Taken from SipHash/main.c */
+/*
+   SipHash-2-4 output with
+   k = 00 01 02 ...
+   and
+   in = (empty string)
+   in = 00 (1 byte)
+   in = 00 01 (2 bytes)
+   in = 00 01 02 (3 bytes)
+   ...
+   in = 00 01 02 ... 3e (63 bytes)
+ */
+static const uint8_t vectors[][sizeof(uint64_t)] =
+{
+  { 0x31, 0x0e, 0x0e, 0xdd, 0x47, 0xdb, 0x6f, 0x72, },
+  { 0xfd, 0x67, 0xdc, 0x93, 0xc5, 0x39, 0xf8, 0x74, },
+  { 0x5a, 0x4f, 0xa9, 0xd9, 0x09, 0x80, 0x6c, 0x0d, },
+  { 0x2d, 0x7e, 0xfb, 0xd7, 0x96, 0x66, 0x67, 0x85, },
+  { 0xb7, 0x87, 0x71, 0x27, 0xe0, 0x94, 0x27, 0xcf, },
+  { 0x8d, 0xa6, 0x99, 0xcd, 0x64, 0x55, 0x76, 0x18, },
+  { 0xce, 0xe3, 0xfe, 0x58, 0x6e, 0x46, 0xc9, 0xcb, },
+  { 0x37, 0xd1, 0x01, 0x8b, 0xf5, 0x00, 0x02, 0xab, },
+  { 0x62, 0x24, 0x93, 0x9a, 0x79, 0xf5, 0xf5, 0x93, },
+  { 0xb0, 0xe4, 0xa9, 0x0b, 0xdf, 0x82, 0x00, 0x9e, },
+  { 0xf3, 0xb9, 0xdd, 0x94, 0xc5, 0xbb, 0x5d, 0x7a, },
+  { 0xa7, 0xad, 0x6b, 0x22, 0x46, 0x2f, 0xb3, 0xf4, },
+  { 0xfb, 0xe5, 0x0e, 0x86, 0xbc, 0x8f, 0x1e, 0x75, },
+  { 0x90, 0x3d, 0x84, 0xc0, 0x27, 0x56, 0xea, 0x14, },
+  { 0xee, 0xf2, 0x7a, 0x8e, 0x90, 0xca, 0x23, 0xf7, },
+  { 0xe5, 0x45, 0xbe, 0x49, 0x61, 0xca, 0x29, 0xa1, },
+  { 0xdb, 0x9b, 0xc2, 0x57, 0x7f, 0xcc, 0x2a, 0x3f, },
+  { 0x94, 0x47, 0xbe, 0x2c, 0xf5, 0xe9, 0x9a, 0x69, },
+  { 0x9c, 0xd3, 0x8d, 0x96, 0xf0, 0xb3, 0xc1, 0x4b, },
+  { 0xbd, 0x61, 0x79, 0xa7, 0x1d, 0xc9, 0x6d, 0xbb, },
+  { 0x98, 0xee, 0xa2, 0x1a, 0xf2, 0x5c, 0xd6, 0xbe, },
+  { 0xc7, 0x67, 0x3b, 0x2e, 0xb0, 0xcb, 0xf2, 0xd0, },
+  { 0x88, 0x3e, 0xa3, 0xe3, 0x95, 0x67, 0x53, 0x93, },
+  { 0xc8, 0xce, 0x5c, 0xcd, 0x8c, 0x03, 0x0c, 0xa8, },
+  { 0x94, 0xaf, 0x49, 0xf6, 0xc6, 0x50, 0xad, 0xb8, },
+  { 0xea, 0xb8, 0x85, 0x8a, 0xde, 0x92, 0xe1, 0xbc, },
+  { 0xf3, 0x15, 0xbb, 0x5b, 0xb8, 0x35, 0xd8, 0x17, },
+  { 0xad, 0xcf, 0x6b, 0x07, 0x63, 0x61, 0x2e, 0x2f, },
+  { 0xa5, 0xc9, 0x1d, 0xa7, 0xac, 0xaa, 0x4d, 0xde, },
+  { 0x71, 0x65, 0x95, 0x87, 0x66, 0x50, 0xa2, 0xa6, },
+  { 0x28, 0xef, 0x49, 0x5c, 0x53, 0xa3, 0x87, 0xad, },
+  { 0x42, 0xc3, 0x41, 0xd8, 0xfa, 0x92, 0xd8, 0x32, },
+  { 0xce, 0x7c, 0xf2, 0x72, 0x2f, 0x51, 0x27, 0x71, },
+  { 0xe3, 0x78, 0x59, 0xf9, 0x46, 0x23, 0xf3, 0xa7, },
+  { 0x38, 0x12, 0x05, 0xbb, 0x1a, 0xb0, 0xe0, 0x12, },
+  { 0xae, 0x97, 0xa1, 0x0f, 0xd4, 0x34, 0xe0, 0x15, },
+  { 0xb4, 0xa3, 0x15, 0x08, 0xbe, 0xff, 0x4d, 0x31, },
+  { 0x81, 0x39, 0x62, 0x29, 0xf0, 0x90, 0x79, 0x02, },
+  { 0x4d, 0x0c, 0xf4, 0x9e, 0xe5, 0xd4, 0xdc, 0xca, },
+  { 0x5c, 0x73, 0x33, 0x6a, 0x76, 0xd8, 0xbf, 0x9a, },
+  { 0xd0, 0xa7, 0x04, 0x53, 0x6b, 0xa9, 0x3e, 0x0e, },
+  { 0x92, 0x59, 0x58, 0xfc, 0xd6, 0x42, 0x0c, 0xad, },
+  { 0xa9, 0x15, 0xc2, 0x9b, 0xc8, 0x06, 0x73, 0x18, },
+  { 0x95, 0x2b, 0x79, 0xf3, 0xbc, 0x0a, 0xa6, 0xd4, },
+  { 0xf2, 0x1d, 0xf2, 0xe4, 0x1d, 0x45, 0x35, 0xf9, },
+  { 0x87, 0x57, 0x75, 0x19, 0x04, 0x8f, 0x53, 0xa9, },
+  { 0x10, 0xa5, 0x6c, 0xf5, 0xdf, 0xcd, 0x9a, 0xdb, },
+  { 0xeb, 0x75, 0x09, 0x5c, 0xcd, 0x98, 0x6c, 0xd0, },
+  { 0x51, 0xa9, 0xcb, 0x9e, 0xcb, 0xa3, 0x12, 0xe6, },
+  { 0x96, 0xaf, 0xad, 0xfc, 0x2c, 0xe6, 0x66, 0xc7, },
+  { 0x72, 0xfe, 0x52, 0x97, 0x5a, 0x43, 0x64, 0xee, },
+  { 0x5a, 0x16, 0x45, 0xb2, 0x76, 0xd5, 0x92, 0xa1, },
+  { 0xb2, 0x74, 0xcb, 0x8e, 0xbf, 0x87, 0x87, 0x0a, },
+  { 0x6f, 0x9b, 0xb4, 0x20, 0x3d, 0xe7, 0xb3, 0x81, },
+  { 0xea, 0xec, 0xb2, 0xa3, 0x0b, 0x22, 0xa8, 0x7f, },
+  { 0x99, 0x24, 0xa4, 0x3c, 0xc1, 0x31, 0x57, 0x24, },
+  { 0xbd, 0x83, 0x8d, 0x3a, 0xaf, 0xbf, 0x8d, 0xb7, },
+  { 0x0b, 0x1a, 0x2a, 0x32, 0x65, 0xd5, 0x1a, 0xea, },
+  { 0x13, 0x50, 0x79, 0xa3, 0x23, 0x1c, 0xe6, 0x60, },
+  { 0x93, 0x2b, 0x28, 0x46, 0xe4, 0xd7, 0x06, 0x66, },
+  { 0xe1, 0x91, 0x5f, 0x5c, 0xb1, 0xec, 0xa4, 0x6c, },
+  { 0xf3, 0x25, 0x96, 0x5c, 0xa1, 0x6d, 0x62, 0x9f, },
+  { 0x57, 0x5f, 0xf2, 0x8e, 0x60, 0x38, 0x1b, 0xe5, },
+  { 0x72, 0x45, 0x06, 0xeb, 0x4c, 0x32, 0x8a, 0x95, }
+};
+
+#define MAXLEN (sizeof(vectors)/sizeof(vectors[0]))
+
+int main(void)
+{
+	struct siphash24_ctx ctx1 = SIPHASH24_INIT(0x0706050403020100ULL,
+						   0x0f0e0d0c0b0a0908ULL);
+	struct siphash24_ctx ctx2;
+	struct siphash_seed seed;
+	leint64_t v;
+	uint8_t in[MAXLEN];
+	int i;
+
+	/* This is how many tests you plan to run */
+	plan_tests(1 + MAXLEN * 2);
+
+	/* Initialzed an manually created should give same results. */
+	for (i = 0; i < sizeof(seed.u.u8); i++)
+		seed.u.u8[i] = i;
+	siphash24_init(&ctx2, &seed);
+	ok1(memcmp(&ctx1, &ctx2, sizeof(ctx1)) == 0);
+
+	for (i = 0; i < MAXLEN; ++i) {
+		memcpy(&v, vectors[i], sizeof(v));
+		in[i] = i;
+		ok1(siphash24(&seed, in, i) == v);
+	}
+
+
+	/* Now try splitting last one along all possible lines. */
+	memcpy(&v, vectors[MAXLEN-1], sizeof(v));
+	for (i = 0; i < MAXLEN; ++i) {
+		struct siphash24_ctx ctx = SIPHASH24_INIT(0x0706050403020100ULL,
+							  0x0f0e0d0c0b0a0908ULL);
+		siphash24_update(&ctx, in, i);
+		siphash24_update(&ctx, in + i, MAXLEN - i - 1);
+		ok1(siphash24_done(&ctx) == v);
+	}
+
+	/* This exits depending on whether all tests passed */
+	return exit_status();
+}