Init project: copy files and skeletons from others

1 files changed, 644 insertions, 0 deletions

diff --git a/src/hash.c b/src/hash.c
new file mode 100644
index 0000000..c8fd5d6
--- /dev/null
+++ b/src/hash.c
@@ -0,0 +1,644 @@
+#include "config.h"
+
+#include <assert.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <string.h>
+#include <pthread.h>
+
+#include "logerr.h"
+#include "random.h"
+#include "hash.h"
+
+#ifdef TEST
+#include "testing.h"
+#endif
+
+
+// FIXME: verify that this is the correct type of mutex for the use case
+static pthread_mutex_t
+SEED_INIT_MUTEX = PTHREAD_MUTEX_INITIALIZER;
+
+#define PRIV_SEED_LENGTH 16
+
+struct Seed {
+	bool initialized;
+	uint8_t bytes[PRIV_SEED_LENGTH];
+};
+
+static struct Seed
+SEED = {
+	.initialized = false,
+	.bytes = { 0 },
+};
+
+
+int
+hash_init(void) {
+	int rc = 0;
+
+	int ret = 0;
+	struct Seed seed = { 0 };
+
+	if (SEED.initialized) {
+		goto out;
+	}
+
+	if (urandom_bytes(sizeof(seed.bytes), &seed.bytes)) {
+		logerr("urandom_bytes(sizeof(seed.bytes), &seed.bytes);\n");
+		rc = -1;
+		goto out;
+	}
+
+	ret = pthread_mutex_lock(&SEED_INIT_MUTEX);
+	if (ret) {
+		logerr(
+			"pthread_mutex_lock(&SEED_INIT_MUTEX): %s;\n",
+			strerror(ret)
+		);
+		rc = -1;
+		goto out;
+	}
+
+	/*
+	   In case where the seed was initialized by another thread while the
+	   current was enterinig hash_init() and locking the mutex.  The
+	   previous check is only a best-effort one to avoid all threads that
+	   start at the same time to serially acquire the mutex and do nothing
+	   with.  In order to sometimes avoid the extra overhead, the previous
+	   check exists, but only the following check that has any correctness
+	   guarantee, and instead of being best-effort it blocks others so it
+	   can make the correct decision.
+	*/
+	if (SEED.initialized) {
+		goto out;
+	}
+
+	// FIXME: memcpy?
+	const uint8_t length = sizeof(SEED.bytes) / sizeof(SEED.bytes[0]);
+	for (uint8_t i = 0; i < length; i++) {
+		SEED.bytes[i] = seed.bytes[i];
+	}
+
+	SEED.initialized = true;
+
+out:
+	// FIXME: verify that unlocking an unlocked mutex is fine
+	ret = pthread_mutex_unlock(&SEED_INIT_MUTEX);
+	if (ret) {
+		logerr(
+			"pthread_mutex_unlock(&SEED_INIT_MUTEX): %s\n",
+			strerror(ret)
+		);
+		rc = -1;
+	}
+	return rc;
+}
+
+#ifdef TEST
+static void *
+hash_init_thread(void *data) {
+	int *ret = (int *)data;
+	*ret = hash_init();
+	pthread_exit(NULL);
+	return NULL;
+}
+
+static int
+test_hash_init(void) {
+	int rc = 0;
+
+	test_start("hash_init()");
+
+	const uint8_t length = sizeof(SEED.bytes) / sizeof(SEED.bytes[0]);
+
+	assert(length == 16);
+	for (uint8_t i = 0; i < length; i++) {
+		assert(SEED.bytes[i] == 0);
+	}
+
+	pthread_mutex_t test_mutex = PTHREAD_MUTEX_INITIALIZER;
+	int ret;
+
+	{
+		testing("when is initialized we do nothing");
+
+		SEED.initialized = true;
+		assert(hash_init() == 0);
+
+		for (uint8_t i = 0; i < length; i++) {
+			assert(SEED.bytes[i] == 0);
+		}
+
+		test_ok();
+	}
+
+	{
+		testing("do nothing when initialized on the second check");
+
+		/*
+		   0. start with an unitialized seed
+		   1. grab the lock
+		   2. start the other thread
+		   3. set SEED_INITIALIZED
+		   4. release the lock
+		   5. join the other thread
+		   6. assert HASH_SEED stilll empty
+		*/
+
+		SEED.initialized = false;                                   // 0
+		ret = pthread_mutex_lock(&test_mutex);                      // 1
+		if (ret) {
+			logerr(
+				"pthread_mutex_lock(&test_mutex): %s;\n",
+				strerror(ret)
+			);
+			rc = -1;
+			goto out;
+		}
+
+		pthread_t t;
+		int t_rc = -1;
+		ret = pthread_create(&t, NULL, hash_init_thread, &t_rc);    // 2
+		if (ret) {
+			logerr("pthread_create(%s, %s, %s, %s): %s\n",
+				"&t",
+				"NULL",
+				"hash_init",
+				"&t_rc",
+				strerror(ret));
+			rc = -1;
+			goto out;
+		}
+
+		SEED.initialized = true;                                    // 3
+		ret = pthread_mutex_unlock(&test_mutex);                    // 4
+		if (ret) {
+			logerr(
+				"pthread_mutex_unlock(&test_mutex): %s\n",
+				strerror(ret)
+			);
+			rc = -1;
+			goto out;
+		}
+
+		ret = pthread_join(t, NULL);                                // 5
+		if (ret) {
+			logerr("pthread_join(t, &rc): %s\n", strerror(ret));
+			rc = -1;
+			goto out;
+		}
+
+		if (t_rc) {
+			logerr("hash_init() in pthread_t\n");
+			rc = -1;
+			goto out;
+		}
+
+		for (size_t i = 0; i < length; i++) {
+			assert(SEED.bytes[i] == 0);                          // 6
+		}
+
+		test_ok();
+	}
+
+	{
+		testing("competing threads can init the seed besides us");
+
+		/*
+		   0. start with an unitialized seed
+		   1. grab the lock
+		   2. start the other 2 threads
+		   3. release the lock
+		   4. join the other threads
+		   5. assert(SEED_INITIALIZED == true);
+		*/
+
+		SEED.initialized = false;                                   // 0
+		ret = pthread_mutex_lock(&test_mutex);                      // 1
+		if (ret) {
+			logerr(
+				"pthread_mutex_lock(&SEED_INIT_MUTEX): %s;\n",
+				strerror(ret)
+			);
+			rc = -1;
+			goto out;
+		}
+
+		pthread_t t1;
+		int t1_rc = -1;
+		ret = pthread_create(&t1, NULL, hash_init_thread, &t1_rc);  // 2
+		if (ret) {
+			logerr("pthread_create(%s, %s, %s, %s): %s\n",
+				"&t1",
+				"NULL",
+				"hash_init",
+				"&t1_rc",
+				strerror(ret));
+			rc = -1;
+			goto out;
+		}
+
+		pthread_t t2;
+		int t2_rc = -1;
+		ret = pthread_create(&t2, NULL, hash_init_thread, &t2_rc);  // 2
+		if (ret) {
+			logerr("pthread_create(%s, %s, %s, %s): %s\n",
+				"&t2",
+				"NULL",
+				"hash_init",
+				"&t2_rc",
+				strerror(ret));
+			rc = -1;
+			goto out;
+		}
+
+		ret = pthread_mutex_unlock(&test_mutex);                    // 3
+		if (ret) {
+			logerr(
+				"pthread_mutex_unlock(&test_mutex): %s\n",
+				strerror(ret)
+			);
+			rc = -1;
+			goto out;
+		}
+
+		ret = pthread_join(t1, NULL);                               // 4
+		if (ret) {
+			logerr("pthread_join(t1, &rc): %s\n", strerror(ret));
+			rc = -1;
+			goto out;
+		}
+
+		if (t1_rc) {
+			logerr("hash_init() in pthread_t t1\n");
+			rc = -1;
+			goto out;
+		}
+
+		ret = pthread_join(t2, NULL);                               // 4
+		if (ret) {
+			logerr("pthread_join(t2, &rc): %s\n", strerror(ret));
+			rc = -1;
+			goto out;
+		}
+
+		if (t2_rc) {
+			logerr("hash_init() in pthread_t t2\n");
+			rc = -1;
+			goto out;
+		}
+
+		assert(SEED.initialized == true);                           // 5
+
+		test_ok();
+	}
+
+out:
+	ret = pthread_mutex_unlock(&test_mutex);
+	if (ret) {
+		logerr(
+			"pthread_mutex_unlock(&test_mutex): %s\n",
+			strerror(ret)
+		);
+		rc = -1;
+	}
+	return rc;
+}
+#endif
+
+
+#define ROTL(x, b) (uint64_t)(((x) << (b)) | ((x) >> (64 - (b))))
+
+#define U32TO8_LE(p, v)                                                        \
+    (p)[0] = (uint8_t)((v));                                                   \
+    (p)[1] = (uint8_t)((v) >> 8);                                              \
+    (p)[2] = (uint8_t)((v) >> 16);                                             \
+    (p)[3] = (uint8_t)((v) >> 24);
+
+#define U64TO8_LE(p, v)                                                        \
+    U32TO8_LE((p), (uint32_t)((v)));                                           \
+    U32TO8_LE((p) + 4, (uint32_t)((v) >> 32));
+
+#define U8TO64_LE(p)                                                           \
+    (((uint64_t)((p)[0])) | ((uint64_t)((p)[1]) << 8) |                        \
+     ((uint64_t)((p)[2]) << 16) | ((uint64_t)((p)[3]) << 24) |                 \
+     ((uint64_t)((p)[4]) << 32) | ((uint64_t)((p)[5]) << 40) |                 \
+     ((uint64_t)((p)[6]) << 48) | ((uint64_t)((p)[7]) << 56))
+
+#define SIPROUND                                                               \
+    do {                                                                       \
+        v0 += v1;                                                              \
+        v1 = ROTL(v1, 13);                                                     \
+        v1 ^= v0;                                                              \
+        v0 = ROTL(v0, 32);                                                     \
+        v2 += v3;                                                              \
+        v3 = ROTL(v3, 16);                                                     \
+        v3 ^= v2;                                                              \
+        v0 += v3;                                                              \
+        v3 = ROTL(v3, 21);                                                     \
+        v3 ^= v0;                                                              \
+        v2 += v1;                                                              \
+        v1 = ROTL(v1, 17);                                                     \
+        v1 ^= v2;                                                              \
+        v2 = ROTL(v2, 32);                                                     \
+    } while (0)
+
+/**
+ * Computes a SipHash value
+ * [in]  key: pointer to the key data (read-only), must be 16 bytes
+ * [in]  input: pointer to input data (read-only)
+ * [in]  inlen: input data length in bytes (any size_t value)
+ * [out] out: pointer to output data (write-only), 16 bytes must be allocated
+ *
+ * @tags infallible
+*/
+static void
+sip_hash(
+	const uint8_t *const key,
+	const size_t inlen,
+	const void *const input,
+	uint8_t out[OUTPUT_LENGTH]
+) {
+	static const int cROUNDS = 2;
+	static const int dROUNDS = 4;
+
+	const unsigned char *ni = (const unsigned char *)input;
+	const unsigned char *kk = (const unsigned char *)key;
+
+	uint64_t v0 = UINT64_C(0x736f6d6570736575);
+	uint64_t v1 = UINT64_C(0x646f72616e646f6d);
+	uint64_t v2 = UINT64_C(0x6c7967656e657261);
+	uint64_t v3 = UINT64_C(0x7465646279746573);
+	uint64_t k0 = U8TO64_LE(kk);      /// Here we are relying on `key` to
+	uint64_t k1 = U8TO64_LE(kk + 8);  /// be 16 bytes long.
+	uint64_t m;
+	int i;
+	const unsigned char *end = ni + inlen - (inlen % sizeof(uint64_t));
+	const int left = inlen & 7;
+	uint64_t b = ((uint64_t)inlen) << 56;
+	v3 ^= k1;
+	v2 ^= k0;
+	v1 ^= k1;
+	v0 ^= k0;
+
+	v1 ^= 0xee;
+
+	for (; ni != end; ni += 8) {
+		m = U8TO64_LE(ni);
+		v3 ^= m;
+
+		for (i = 0; i < cROUNDS; ++i) {
+			SIPROUND;
+		}
+
+		v0 ^= m;
+	}
+
+	switch (left) {
+		case 7:
+			b |= ((uint64_t)ni[6]) << 48;
+			/* fall-through */
+		case 6:
+			b |= ((uint64_t)ni[5]) << 40;
+			/* fall-through */
+		case 5:
+			b |= ((uint64_t)ni[4]) << 32;
+			/* fall-through */
+		case 4:
+			b |= ((uint64_t)ni[3]) << 24;
+			/* fall-through */
+		case 3:
+			b |= ((uint64_t)ni[2]) << 16;
+			/* fall-through */
+		case 2:
+			b |= ((uint64_t)ni[1]) << 8;
+			/* fall-through */
+		case 1:
+			b |= ((uint64_t)ni[0]);
+			break;
+		case 0:
+			break;
+	}
+
+	v3 ^= b;
+
+	for (i = 0; i < cROUNDS; ++i) {
+		SIPROUND;
+	}
+
+	v0 ^= b;
+
+	v2 ^= 0xee;
+
+	for (i = 0; i < dROUNDS; ++i) {
+		SIPROUND;
+	}
+
+	b = v0 ^ v1 ^ v2 ^ v3;
+	U64TO8_LE(out, b);
+
+	v1 ^= 0xdd;
+
+	for (i = 0; i < dROUNDS; ++i) {
+		SIPROUND;
+	}
+
+	b = v0 ^ v1 ^ v2 ^ v3;
+	U64TO8_LE(out + 8, b);
+
+	return;
+}
+
+#ifdef TEST
+static const uint8_t
+TEST_VECTORS[64][OUTPUT_LENGTH] = {
+    { 0xa3, 0x81, 0x7f, 0x04, 0xba, 0x25, 0xa8, 0xe6, 0x6d, 0xf6, 0x72, 0x14, 0xc7, 0x55, 0x02, 0x93 },
+    { 0xda, 0x87, 0xc1, 0xd8, 0x6b, 0x99, 0xaf, 0x44, 0x34, 0x76, 0x59, 0x11, 0x9b, 0x22, 0xfc, 0x45 },
+    { 0x81, 0x77, 0x22, 0x8d, 0xa4, 0xa4, 0x5d, 0xc7, 0xfc, 0xa3, 0x8b, 0xde, 0xf6, 0x0a, 0xff, 0xe4 },
+    { 0x9c, 0x70, 0xb6, 0x0c, 0x52, 0x67, 0xa9, 0x4e, 0x5f, 0x33, 0xb6, 0xb0, 0x29, 0x85, 0xed, 0x51 },
+    { 0xf8, 0x81, 0x64, 0xc1, 0x2d, 0x9c, 0x8f, 0xaf, 0x7d, 0x0f, 0x6e, 0x7c, 0x7b, 0xcd, 0x55, 0x79 },
+    { 0x13, 0x68, 0x87, 0x59, 0x80, 0x77, 0x6f, 0x88, 0x54, 0x52, 0x7a, 0x07, 0x69, 0x0e, 0x96, 0x27 },
+    { 0x14, 0xee, 0xca, 0x33, 0x8b, 0x20, 0x86, 0x13, 0x48, 0x5e, 0xa0, 0x30, 0x8f, 0xd7, 0xa1, 0x5e },
+    { 0xa1, 0xf1, 0xeb, 0xbe, 0xd8, 0xdb, 0xc1, 0x53, 0xc0, 0xb8, 0x4a, 0xa6, 0x1f, 0xf0, 0x82, 0x39 },
+    { 0x3b, 0x62, 0xa9, 0xba, 0x62, 0x58, 0xf5, 0x61, 0x0f, 0x83, 0xe2, 0x64, 0xf3, 0x14, 0x97, 0xb4 },
+    { 0x26, 0x44, 0x99, 0x06, 0x0a, 0xd9, 0xba, 0xab, 0xc4, 0x7f, 0x8b, 0x02, 0xbb, 0x6d, 0x71, 0xed },
+    { 0x00, 0x11, 0x0d, 0xc3, 0x78, 0x14, 0x69, 0x56, 0xc9, 0x54, 0x47, 0xd3, 0xf3, 0xd0, 0xfb, 0xba },
+    { 0x01, 0x51, 0xc5, 0x68, 0x38, 0x6b, 0x66, 0x77, 0xa2, 0xb4, 0xdc, 0x6f, 0x81, 0xe5, 0xdc, 0x18 },
+    { 0xd6, 0x26, 0xb2, 0x66, 0x90, 0x5e, 0xf3, 0x58, 0x82, 0x63, 0x4d, 0xf6, 0x85, 0x32, 0xc1, 0x25 },
+    { 0x98, 0x69, 0xe2, 0x47, 0xe9, 0xc0, 0x8b, 0x10, 0xd0, 0x29, 0x93, 0x4f, 0xc4, 0xb9, 0x52, 0xf7 },
+    { 0x31, 0xfc, 0xef, 0xac, 0x66, 0xd7, 0xde, 0x9c, 0x7e, 0xc7, 0x48, 0x5f, 0xe4, 0x49, 0x49, 0x02 },
+    { 0x54, 0x93, 0xe9, 0x99, 0x33, 0xb0, 0xa8, 0x11, 0x7e, 0x08, 0xec, 0x0f, 0x97, 0xcf, 0xc3, 0xd9 },
+    { 0x6e, 0xe2, 0xa4, 0xca, 0x67, 0xb0, 0x54, 0xbb, 0xfd, 0x33, 0x15, 0xbf, 0x85, 0x23, 0x05, 0x77 },
+    { 0x47, 0x3d, 0x06, 0xe8, 0x73, 0x8d, 0xb8, 0x98, 0x54, 0xc0, 0x66, 0xc4, 0x7a, 0xe4, 0x77, 0x40 },
+    { 0xa4, 0x26, 0xe5, 0xe4, 0x23, 0xbf, 0x48, 0x85, 0x29, 0x4d, 0xa4, 0x81, 0xfe, 0xae, 0xf7, 0x23 },
+    { 0x78, 0x01, 0x77, 0x31, 0xcf, 0x65, 0xfa, 0xb0, 0x74, 0xd5, 0x20, 0x89, 0x52, 0x51, 0x2e, 0xb1 },
+    { 0x9e, 0x25, 0xfc, 0x83, 0x3f, 0x22, 0x90, 0x73, 0x3e, 0x93, 0x44, 0xa5, 0xe8, 0x38, 0x39, 0xeb },
+    { 0x56, 0x8e, 0x49, 0x5a, 0xbe, 0x52, 0x5a, 0x21, 0x8a, 0x22, 0x14, 0xcd, 0x3e, 0x07, 0x1d, 0x12 },
+    { 0x4a, 0x29, 0xb5, 0x45, 0x52, 0xd1, 0x6b, 0x9a, 0x46, 0x9c, 0x10, 0x52, 0x8e, 0xff, 0x0a, 0xae },
+    { 0xc9, 0xd1, 0x84, 0xdd, 0xd5, 0xa9, 0xf5, 0xe0, 0xcf, 0x8c, 0xe2, 0x9a, 0x9a, 0xbf, 0x69, 0x1c },
+    { 0x2d, 0xb4, 0x79, 0xae, 0x78, 0xbd, 0x50, 0xd8, 0x88, 0x2a, 0x8a, 0x17, 0x8a, 0x61, 0x32, 0xad },
+    { 0x8e, 0xce, 0x5f, 0x04, 0x2d, 0x5e, 0x44, 0x7b, 0x50, 0x51, 0xb9, 0xea, 0xcb, 0x8d, 0x8f, 0x6f },
+    { 0x9c, 0x0b, 0x53, 0xb4, 0xb3, 0xc3, 0x07, 0xe8, 0x7e, 0xae, 0xe0, 0x86, 0x78, 0x14, 0x1f, 0x66 },
+    { 0xab, 0xf2, 0x48, 0xaf, 0x69, 0xa6, 0xea, 0xe4, 0xbf, 0xd3, 0xeb, 0x2f, 0x12, 0x9e, 0xeb, 0x94 },
+    { 0x06, 0x64, 0xda, 0x16, 0x68, 0x57, 0x4b, 0x88, 0xb9, 0x35, 0xf3, 0x02, 0x73, 0x58, 0xae, 0xf4 },
+    { 0xaa, 0x4b, 0x9d, 0xc4, 0xbf, 0x33, 0x7d, 0xe9, 0x0c, 0xd4, 0xfd, 0x3c, 0x46, 0x7c, 0x6a, 0xb7 },
+    { 0xea, 0x5c, 0x7f, 0x47, 0x1f, 0xaf, 0x6b, 0xde, 0x2b, 0x1a, 0xd7, 0xd4, 0x68, 0x6d, 0x22, 0x87 },
+    { 0x29, 0x39, 0xb0, 0x18, 0x32, 0x23, 0xfa, 0xfc, 0x17, 0x23, 0xde, 0x4f, 0x52, 0xc4, 0x3d, 0x35 },
+    { 0x7c, 0x39, 0x56, 0xca, 0x5e, 0xea, 0xfc, 0x3e, 0x36, 0x3e, 0x9d, 0x55, 0x65, 0x46, 0xeb, 0x68 },
+    { 0x77, 0xc6, 0x07, 0x71, 0x46, 0xf0, 0x1c, 0x32, 0xb6, 0xb6, 0x9d, 0x5f, 0x4e, 0xa9, 0xff, 0xcf },
+    { 0x37, 0xa6, 0x98, 0x6c, 0xb8, 0x84, 0x7e, 0xdf, 0x09, 0x25, 0xf0, 0xf1, 0x30, 0x9b, 0x54, 0xde },
+    { 0xa7, 0x05, 0xf0, 0xe6, 0x9d, 0xa9, 0xa8, 0xf9, 0x07, 0x24, 0x1a, 0x2e, 0x92, 0x3c, 0x8c, 0xc8 },
+    { 0x3d, 0xc4, 0x7d, 0x1f, 0x29, 0xc4, 0x48, 0x46, 0x1e, 0x9e, 0x76, 0xed, 0x90, 0x4f, 0x67, 0x11 },
+    { 0x0d, 0x62, 0xbf, 0x01, 0xe6, 0xfc, 0x0e, 0x1a, 0x0d, 0x3c, 0x47, 0x51, 0xc5, 0xd3, 0x69, 0x2b },
+    { 0x8c, 0x03, 0x46, 0x8b, 0xca, 0x7c, 0x66, 0x9e, 0xe4, 0xfd, 0x5e, 0x08, 0x4b, 0xbe, 0xe7, 0xb5 },
+    { 0x52, 0x8a, 0x5b, 0xb9, 0x3b, 0xaf, 0x2c, 0x9c, 0x44, 0x73, 0xcc, 0xe5, 0xd0, 0xd2, 0x2b, 0xd9 },
+    { 0xdf, 0x6a, 0x30, 0x1e, 0x95, 0xc9, 0x5d, 0xad, 0x97, 0xae, 0x0c, 0xc8, 0xc6, 0x91, 0x3b, 0xd8 },
+    { 0x80, 0x11, 0x89, 0x90, 0x2c, 0x85, 0x7f, 0x39, 0xe7, 0x35, 0x91, 0x28, 0x5e, 0x70, 0xb6, 0xdb },
+    { 0xe6, 0x17, 0x34, 0x6a, 0xc9, 0xc2, 0x31, 0xbb, 0x36, 0x50, 0xae, 0x34, 0xcc, 0xca, 0x0c, 0x5b },
+    { 0x27, 0xd9, 0x34, 0x37, 0xef, 0xb7, 0x21, 0xaa, 0x40, 0x18, 0x21, 0xdc, 0xec, 0x5a, 0xdf, 0x89 },
+    { 0x89, 0x23, 0x7d, 0x9d, 0xed, 0x9c, 0x5e, 0x78, 0xd8, 0xb1, 0xc9, 0xb1, 0x66, 0xcc, 0x73, 0x42 },
+    { 0x4a, 0x6d, 0x80, 0x91, 0xbf, 0x5e, 0x7d, 0x65, 0x11, 0x89, 0xfa, 0x94, 0xa2, 0x50, 0xb1, 0x4c },
+    { 0x0e, 0x33, 0xf9, 0x60, 0x55, 0xe7, 0xae, 0x89, 0x3f, 0xfc, 0x0e, 0x3d, 0xcf, 0x49, 0x29, 0x02 },
+    { 0xe6, 0x1c, 0x43, 0x2b, 0x72, 0x0b, 0x19, 0xd1, 0x8e, 0xc8, 0xd8, 0x4b, 0xdc, 0x63, 0x15, 0x1b },
+    { 0xf7, 0xe5, 0xae, 0xf5, 0x49, 0xf7, 0x82, 0xcf, 0x37, 0x90, 0x55, 0xa6, 0x08, 0x26, 0x9b, 0x16 },
+    { 0x43, 0x8d, 0x03, 0x0f, 0xd0, 0xb7, 0xa5, 0x4f, 0xa8, 0x37, 0xf2, 0xad, 0x20, 0x1a, 0x64, 0x03 },
+    { 0xa5, 0x90, 0xd3, 0xee, 0x4f, 0xbf, 0x04, 0xe3, 0x24, 0x7e, 0x0d, 0x27, 0xf2, 0x86, 0x42, 0x3f },
+    { 0x5f, 0xe2, 0xc1, 0xa1, 0x72, 0xfe, 0x93, 0xc4, 0xb1, 0x5c, 0xd3, 0x7c, 0xae, 0xf9, 0xf5, 0x38 },
+    { 0x2c, 0x97, 0x32, 0x5c, 0xbd, 0x06, 0xb3, 0x6e, 0xb2, 0x13, 0x3d, 0xd0, 0x8b, 0x3a, 0x01, 0x7c },
+    { 0x92, 0xc8, 0x14, 0x22, 0x7a, 0x6b, 0xca, 0x94, 0x9f, 0xf0, 0x65, 0x9f, 0x00, 0x2a, 0xd3, 0x9e },
+    { 0xdc, 0xe8, 0x50, 0x11, 0x0b, 0xd8, 0x32, 0x8c, 0xfb, 0xd5, 0x08, 0x41, 0xd6, 0x91, 0x1d, 0x87 },
+    { 0x67, 0xf1, 0x49, 0x84, 0xc7, 0xda, 0x79, 0x12, 0x48, 0xe3, 0x2b, 0xb5, 0x92, 0x25, 0x83, 0xda },
+    { 0x19, 0x38, 0xf2, 0xcf, 0x72, 0xd5, 0x4e, 0xe9, 0x7e, 0x94, 0x16, 0x6f, 0xa9, 0x1d, 0x2a, 0x36 },
+    { 0x74, 0x48, 0x1e, 0x96, 0x46, 0xed, 0x49, 0xfe, 0x0f, 0x62, 0x24, 0x30, 0x16, 0x04, 0x69, 0x8e },
+    { 0x57, 0xfc, 0xa5, 0xde, 0x98, 0xa9, 0xd6, 0xd8, 0x00, 0x64, 0x38, 0xd0, 0x58, 0x3d, 0x8a, 0x1d },
+    { 0x9f, 0xec, 0xde, 0x1c, 0xef, 0xdc, 0x1c, 0xbe, 0xd4, 0x76, 0x36, 0x74, 0xd9, 0x57, 0x53, 0x59 },
+    { 0xe3, 0x04, 0x0c, 0x00, 0xeb, 0x28, 0xf1, 0x53, 0x66, 0xca, 0x73, 0xcb, 0xd8, 0x72, 0xe7, 0x40 },
+    { 0x76, 0x97, 0x00, 0x9a, 0x6a, 0x83, 0x1d, 0xfe, 0xcc, 0xa9, 0x1c, 0x59, 0x93, 0x67, 0x0f, 0x7a },
+    { 0x58, 0x53, 0x54, 0x23, 0x21, 0xf5, 0x67, 0xa0, 0x05, 0xd5, 0x47, 0xa4, 0xf0, 0x47, 0x59, 0xbd },
+    { 0x51, 0x50, 0xd1, 0x77, 0x2f, 0x50, 0x83, 0x4a, 0x50, 0x3e, 0x06, 0x9a, 0x97, 0x3f, 0xbd, 0x7c },
+};
+
+/**
+ * @tags infallible
+*/
+static void
+test_sip_hash(void) {
+	test_start("sip_hash()");
+
+	{
+		testing("upstream test vectors");
+
+		const size_t LEN = 64;
+		uint8_t in[64 /* LEN */];
+
+		uint8_t out[OUTPUT_LENGTH];
+		struct Seed key;
+
+		const uint8_t length = sizeof(SEED.bytes) / sizeof(SEED.bytes[0]);
+		for (uint8_t i = 0; i < length; ++i) {
+			key.bytes[i] = i;
+		}
+
+		for (uint8_t i = 0; i < LEN; ++i) {
+			in[i] = i;
+		}
+
+		for (uint8_t i = 0; i < LEN; ++i) {
+			sip_hash(key.bytes, i, in, out);
+			for (uint8_t j = 0; j < OUTPUT_LENGTH; j++) {
+				assert(out[j] == TEST_VECTORS[i][j]);
+			}
+		}
+
+		test_ok();
+	}
+
+	return;
+}
+#endif
+
+
+/**
+ * @tags infallible
+*/
+void
+hash(const size_t len, const void *const in, uint8_t out[OUTPUT_LENGTH]) {
+	assert(SEED.initialized && "Missing call to hash_init() before using hash().");
+	sip_hash(SEED.bytes, len, in, out);
+	return;
+}
+
+#ifdef TEST
+/**
+ * @tags infallible
+*/
+static void
+test_hash(void) {
+	test_start("hash()");
+
+	{
+		testing("we get the same hash given the same input");
+
+		uint8_t out1[OUTPUT_LENGTH] = { 0 };
+		uint8_t out2[OUTPUT_LENGTH] = { 0 };
+
+		const char *const input_str = "the input";
+		const uint8_t *const input = (uint8_t *)input_str;
+		const size_t input_length = strlen(input_str);
+
+		hash(input_length, input, out1);
+		hash(input_length, input, out2);
+
+		for (int i = 0; i < OUTPUT_LENGTH; i++) {
+			assert(out1[i] == out2[i]);
+		}
+
+		test_ok();
+	}
+
+	{
+		testing("hashing twice overwrites whatever was in `out`");
+
+		uint8_t out1[OUTPUT_LENGTH];
+		uint8_t out2[OUTPUT_LENGTH];
+
+		const char *const input_str = "another input";
+		const uint8_t *const input = (uint8_t *)input_str;
+		const size_t input_length = strlen(input_str);
+
+		hash(6, (uint8_t *)"before", out1);
+		hash(input_length, input,    out1);
+		hash(input_length, input,    out2);
+
+		for (int i = 0; i < OUTPUT_LENGTH; i++) {
+			assert(out1[i] == out2[i]);
+		}
+
+		test_ok();
+	}
+
+	return;
+}
+#endif
+
+
+#ifdef TEST
+int
+main(void) {
+	int rc = 0;
+
+	if (test_hash_init()) {
+		logerr("test_hash_init();\n");
+		rc = -1;
+		goto out;
+	}
+
+	test_sip_hash();
+	test_hash();
+
+out:
+	return !!rc;
+}
+#endif