laforge has submitted this change. (
https://gerrit.osmocom.org/c/libosmocore/+/36913?usp=email )
Change subject: add jhash.h, copied from linux/jhash.h
......................................................................
add jhash.h, copied from linux/jhash.h
Allow using arbitrary length data as hashtable key:
Copy jhash.h implementation from the linux kernel.
Apply osmo_ prefix to all global symbols.
Add jhash_test to ensure the code import works as intended.
First application will be a hashtable keyed by umts_cell_id in
osmo-hnbgw.git.
Related: SYS#6773
Change-Id: I0c9652bbc9e2a18b1200e7d63bb6f64ded7d75fa
---
M include/osmocom/core/Makefile.am
A include/osmocom/core/jhash.h
M tests/Makefile.am
A tests/jhash/jhash_test.c
A tests/jhash/jhash_test.ok
M tests/testsuite.at
6 files changed, 284 insertions(+), 2 deletions(-)
Approvals:
laforge: Looks good to me, approved
Jenkins Builder: Verified
pespin: Looks good to me, but someone else must approve
osmith: Looks good to me, but someone else must approve
diff --git a/include/osmocom/core/Makefile.am b/include/osmocom/core/Makefile.am
index 7c29ca1..980f813 100644
--- a/include/osmocom/core/Makefile.am
+++ b/include/osmocom/core/Makefile.am
@@ -27,6 +27,7 @@
hashtable.h \
isdnhdlc.h \
it_q.h \
+ jhash.h \
linuxlist.h \
linuxrbtree.h \
log2.h \
diff --git a/include/osmocom/core/jhash.h b/include/osmocom/core/jhash.h
new file mode 100644
index 0000000..763fcd7
--- /dev/null
+++ b/include/osmocom/core/jhash.h
@@ -0,0 +1,171 @@
+#pragma once
+#include <osmocom/core/bit32gen.h>
+
+/* Below is a partial copy of
+ *
https://raw.githubusercontent.com/torvalds/linux/3eb3c33c1d87029a3832e205eebd59cfb56ba3a4/tools/include/linux/bitops.h
+ * with an osmo_ prefix applied to avoid any collisions.
+ */
+/* SPDX-License-Identifier: GPL-2.0 */
+/**
+ * rol32 - rotate a 32-bit value left
+ * @word: value to rotate
+ * @shift: bits to roll
+ */
+static inline uint32_t osmo_rol32(uint32_t word, unsigned int shift)
+{
+ return (word << shift) | (word >> ((-shift) & 31));
+}
+
+/* Below is a partial copy of
+ *
https://raw.githubusercontent.com/torvalds/linux/22c033989c3eb9731ad0c497dfab4231b8e367d6/include/linux/unaligned/packed_struct.h
+ * with an osmo_ prefix applied to avoid any collisions.
+ */
+struct osmo_unaligned_cpu32 {
+ uint32_t x;
+} __attribute__((__packed__));
+
+static inline uint32_t osmo_get_unaligned_cpu32(const void *p)
+{
+ const struct osmo_unaligned_cpu32 *ptr = (const struct
osmo_unaligned_cpu32 *)p;
+ return ptr->x;
+}
+
+/* Below is a partial copy of
+ *
https://raw.githubusercontent.com/torvalds/linux/79e3ea5aab48c83de9410e43b52895406847eca7/tools/include/linux/jhash.h
+ * with an osmo_ prefix applied to avoid any collisions.
+ */
+/* jhash.h: Jenkins hash support.
+ *
+ * Copyright (C) 2006. Bob Jenkins (bob_jenk...@burtleburtle.net)
+ *
+ * https://burtleburtle.net/bob/hash/
+ *
+ * These are the credits from Bob's sources:
+ *
+ * lookup3.c, by Bob Jenkins, May 2006, Public Domain.
+ *
+ * These are functions for producing 32-bit hashes for hash table lookup.
+ * hashword(), hashlittle(), hashlittle2(), hashbig(), mix(), and final()
+ * are externally useful functions. Routines to test the hash are included
+ * if SELF_TEST is defined. You can use this free for any purpose. It's in
+ * the public domain. It has no warranty.
+ *
+ * Copyright (C) 2009-2010 Jozsef Kadlecsik (kad...@blackhole.kfki.hu)
+ *
+ * I've modified Bob's hash to be useful in the Linux kernel, and
+ * any bugs present are my fault.
+ * Jozsef
+ */
+
+/* OSMO_JHASH_MIX -- mix 3 32-bit values reversibly. */
+#define OSMO_JHASH_MIX(a, b, c) \
+{ \
+ a -= c; a ^= osmo_rol32(c, 4); c += b; \
+ b -= a; b ^= osmo_rol32(a, 6); a += c; \
+ c -= b; c ^= osmo_rol32(b, 8); b += a; \
+ a -= c; a ^= osmo_rol32(c, 16); c += b; \
+ b -= a; b ^= osmo_rol32(a, 19); a += c; \
+ c -= b; c ^= osmo_rol32(b, 4); b += a; \
+}
+
+/* OSMO_JHASH_FINAL - final mixing of 3 32-bit values (a,b,c) into c */
+#define OSMO_JHASH_FINAL(a, b, c) \
+{ \
+ c ^= b; c -= osmo_rol32(b, 14); \
+ a ^= c; a -= osmo_rol32(c, 11); \
+ b ^= a; b -= osmo_rol32(a, 25); \
+ c ^= b; c -= osmo_rol32(b, 16); \
+ a ^= c; a -= osmo_rol32(c, 4); \
+ b ^= a; b -= osmo_rol32(a, 14); \
+ c ^= b; c -= osmo_rol32(b, 24); \
+}
+
+/* An arbitrary initial parameter */
+#define JHASH_INITVAL 0xdeadbeef
+
+/* osmo_jhash - hash an arbitrary key
+ * @k: sequence of bytes as key
+ * @length: the length of the key
+ * @initval: the previous hash, or an arbitray value
+ *
+ * The generic version, hashes an arbitrary sequence of bytes.
+ * No alignment or length assumptions are made about the input key.
+ *
+ * Returns the hash value of the key. The result depends on endianness.
+ */
+static inline uint32_t osmo_jhash(const void *key, uint32_t length, uint32_t
initval)
+{
+ uint32_t a, b, c;
+ const uint8_t *k = key;
+
+ /* Set up the internal state */
+ a = b = c = JHASH_INITVAL + length + initval;
+
+ /* All but the last block: affect some 32 bits of (a,b,c) */
+ while (length > 12) {
+ a += osmo_get_unaligned_cpu32(k);
+ b += osmo_get_unaligned_cpu32(k + 4);
+ c += osmo_get_unaligned_cpu32(k + 8);
+ OSMO_JHASH_MIX(a, b, c);
+ length -= 12;
+ k += 12;
+ }
+ /* Last block: affect all 32 bits of (c) */
+ /* All the case statements fall through */
+ switch (length) {
+ case 12: c += (uint32_t)k[11]<<24;
+ case 11: c += (uint32_t)k[10]<<16;
+ case 10: c += (uint32_t)k[9]<<8;
+ case 9: c += k[8];
+ case 8: b += (uint32_t)k[7]<<24;
+ case 7: b += (uint32_t)k[6]<<16;
+ case 6: b += (uint32_t)k[5]<<8;
+ case 5: b += k[4];
+ case 4: a += (uint32_t)k[3]<<24;
+ case 3: a += (uint32_t)k[2]<<16;
+ case 2: a += (uint32_t)k[1]<<8;
+ case 1: a += k[0];
+ OSMO_JHASH_FINAL(a, b, c);
+ case 0: /* Nothing left to add */
+ break;
+ }
+
+ return c;
+}
+
+/* osmo_jhash2 - hash an array of uint32_t's
+ * @k: the key which must be an array of uint32_t's
+ * @length: the number of uint32_t's in the key
+ * @initval: the previous hash, or an arbitray value
+ *
+ * Returns the hash value of the key.
+ */
+static inline uint32_t osmo_jhash2(const uint32_t *k, uint32_t length,
uint32_t initval)
+{
+ uint32_t a, b, c;
+
+ /* Set up the internal state */
+ a = b = c = JHASH_INITVAL + (length<<2) + initval;
+
+ /* Handle most of the key */
+ while (length > 3) {
+ a += k[0];
+ b += k[1];
+ c += k[2];
+ OSMO_JHASH_MIX(a, b, c);
+ length -= 3;
+ k += 3;
+ }
+
+ /* Handle the last 3 uint32_t's: all the case statements fall through */
+ switch (length) {
+ case 3: c += k[2];
+ case 2: b += k[1];
+ case 1: a += k[0];
+ OSMO_JHASH_FINAL(a, b, c);
+ case 0: /* Nothing left to add */
+ break;
+ }
+
+ return c;
+}
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 58900d3..1e8997c 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -59,6 +59,7 @@
osmo_io/osmo_io_test \
soft_uart/soft_uart_test \
rlp/rlp_test \
+ jhash/jhash_test \
$(NULL)
if ENABLE_MSGFILE
@@ -391,6 +392,7 @@
rlp_rlp_test_SOURCES = rlp/rlp_test.c
rlp_rlp_test_LDADD = $(top_builddir)/src/gsm/libosmogsm.la $(LDADD)
+jhash_jhash_test_SOURCES = jhash/jhash_test.c
# The `:;' works around a Bash 3.2 bug when the output is not writeable.
$(srcdir)/package.m4: $(top_srcdir)/configure.ac
@@ -505,6 +507,7 @@
soft_uart/soft_uart_test.ok \
rlp/rlp_test.ok \
socket/socket_sctp_test.ok socket/socket_sctp_test.err \
+ jhash/jhash_test.ok \
$(NULL)
if ENABLE_LIBSCTP
@@ -729,8 +732,9 @@
soft_uart/soft_uart_test \
>$(srcdir)/soft_uart/soft_uart_test.ok
rlp/rlp_test \
- >$(srcdir)/rlp/rlp_test.ok \
- $(NULL)
+ >$(srcdir)/rlp/rlp_test.ok
+ jhash/jhash_test \
+ >$(srcdir)/jhash/jhash_test.ok
check-local: atconfig $(TESTSUITE)
diff --git a/tests/jhash/jhash_test.c b/tests/jhash/jhash_test.c
new file mode 100644
index 0000000..e2c8c71
--- /dev/null
+++ b/tests/jhash/jhash_test.c
@@ -0,0 +1,56 @@
+#include <osmocom/core/linuxlist.h>
+#include <osmocom/core/hashtable.h>
+#include <osmocom/core/jhash.h>
+
+struct item {
+ const char blob[32];
+ struct hlist_node node;
+};
+
+struct item items[] = {
+ { "blob one", },
+ { "blob two and five are the same", },
+ { "third blob", },
+ { "fourth blob", },
+ { "blob two and five are the same", },
+};
+
+uint32_t item_hash(const struct item *item)
+{
+ return osmo_jhash(item->blob, strlen(item->blob), 0);
+}
+
+int main(void)
+{
+ int i;
+ struct item *item;
+
+ DECLARE_HASHTABLE(haystack, 5);
+ hash_init(haystack);
+
+ printf("add:\n");
+ for (i = 0; i < ARRAY_SIZE(items); i++) {
+ uint32_t hash;
+ item = &items[i];
+ hash_add(haystack, &item->node, hash = item_hash(item));
+ printf("- adding items[%d]#%x = %s\n", i, hash, item->blob);
+ }
+
+ printf("list:\n");
+ hash_for_each (haystack, i, item, node)
+ printf("- %s [%d]\n", item->blob, (int)(item - items));
+
+ printf("find:\n");
+ for (i = 0; i < ARRAY_SIZE(items); i++) {
+ uint32_t hash;
+ struct item *needle = &items[i];
+ hash = item_hash(needle);
+ printf("- looking up items[%d]#%x = %s\n", i, hash,
needle->blob);
+ hash_for_each_possible (haystack, item, node, hash)
+ printf(" - %s items[%d]\n",
+ (item == needle) ? "found" : "not",
+ (int)(item - items));
+ }
+
+ return 0;
+}
diff --git a/tests/jhash/jhash_test.ok b/tests/jhash/jhash_test.ok
new file mode 100644
index 0000000..e28ccc4
--- /dev/null
+++ b/tests/jhash/jhash_test.ok
@@ -0,0 +1,25 @@
+add:
+- adding items[0]#b286bb61 = blob one
+- adding items[1]#ad4eb7b = blob two and five are the same
+- adding items[2]#6b8eae61 = third blob
+- adding items[3]#24a546dc = fourth blob
+- adding items[4]#ad4eb7b = blob two and five are the same
+list:
+- blob two and five are the same [4]
+- blob two and five are the same [1]
+- blob one [0]
+- fourth blob [3]
+- third blob [2]
+find:
+- looking up items[0]#b286bb61 = blob one
+ - found items[0]
+- looking up items[1]#ad4eb7b = blob two and five are the same
+ - not items[4]
+ - found items[1]
+- looking up items[2]#6b8eae61 = third blob
+ - found items[2]
+- looking up items[3]#24a546dc = fourth blob
+ - found items[3]
+- looking up items[4]#ad4eb7b = blob two and five are the same
+ - found items[4]
+ - not items[1]
diff --git a/tests/testsuite.at b/tests/testsuite.at
index e721b93..3433fb0 100644
--- a/tests/testsuite.at
+++ b/tests/testsuite.at
@@ -547,3 +547,9 @@
cat $abs_srcdir/rlp/rlp_test.ok > expout
AT_CHECK([$abs_top_builddir/tests/rlp/rlp_test], [0], [expout], [ignore])
AT_CLEANUP
+
+AT_SETUP([jhash])
+AT_KEYWORDS([jhash])
+cat $abs_srcdir/jhash/jhash_test.ok > expout
+AT_CHECK([$abs_top_builddir/tests/jhash/jhash_test], [0], [expout], [ignore])
+AT_CLEANUP
--
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Gerrit-Project: libosmocore
Gerrit-Branch: master
Gerrit-Change-Id: I0c9652bbc9e2a18b1200e7d63bb6f64ded7d75fa
Gerrit-Change-Number: 36913
Gerrit-PatchSet: 6
Gerrit-Owner: neels <nhofm...@sysmocom.de>
Gerrit-Reviewer: Jenkins Builder
Gerrit-Reviewer: laforge <lafo...@osmocom.org>
Gerrit-Reviewer: osmith <osm...@sysmocom.de>
Gerrit-Reviewer: pespin <pes...@sysmocom.de>
Gerrit-MessageType: merged
