From 73a1d367abc056e86f8cd6da4685f9c64c4a724b Mon Sep 17 00:00:00 2001
From: runner02 <runner02@ffnw.de>
Date: Mon, 2 Apr 2018 19:22:28 +0200
Subject: [PATCH 7/7] backport gluon-ebtables-limit-arp
---
package/gluon-ebtables-limit-arp/Makefile | 59 ++
.../files/etc/init.d/gluon-arp-limiter | 14 +
.../files/lib/gluon/ebtables/100-arp-limit-chains | 3 +
.../files/lib/gluon/ebtables/320-arp-limit-rules | 6 +
package/gluon-ebtables-limit-arp/src/LICENSE | 339 +++++++
package/gluon-ebtables-limit-arp/src/Makefile | 14 +
package/gluon-ebtables-limit-arp/src/addr_store.c | 167 ++++
package/gluon-ebtables-limit-arp/src/addr_store.h | 33 +
.../src/gluon-arp-limiter.c | 302 +++++++
.../src/gluon-arp-limiter.h | 13 +
package/gluon-ebtables-limit-arp/src/lookup3.c | 998 +++++++++++++++++++++
package/gluon-ebtables-limit-arp/src/lookup3.h | 6 +
package/gluon-ebtables-limit-arp/src/mac.c | 47 +
package/gluon-ebtables-limit-arp/src/mac.h | 24 +
14 files changed, 2025 insertions(+)
create mode 100644 package/gluon-ebtables-limit-arp/Makefile
create mode 100755 package/gluon-ebtables-limit-arp/files/etc/init.d/gluon-arp-limiter
create mode 100644 package/gluon-ebtables-limit-arp/files/lib/gluon/ebtables/100-arp-limit-chains
create mode 100644 package/gluon-ebtables-limit-arp/files/lib/gluon/ebtables/320-arp-limit-rules
create mode 100644 package/gluon-ebtables-limit-arp/src/LICENSE
create mode 100644 package/gluon-ebtables-limit-arp/src/Makefile
create mode 100644 package/gluon-ebtables-limit-arp/src/addr_store.c
create mode 100644 package/gluon-ebtables-limit-arp/src/addr_store.h
create mode 100644 package/gluon-ebtables-limit-arp/src/gluon-arp-limiter.c
create mode 100644 package/gluon-ebtables-limit-arp/src/gluon-arp-limiter.h
create mode 100644 package/gluon-ebtables-limit-arp/src/lookup3.c
create mode 100644 package/gluon-ebtables-limit-arp/src/lookup3.h
create mode 100644 package/gluon-ebtables-limit-arp/src/mac.c
create mode 100644 package/gluon-ebtables-limit-arp/src/mac.h
diff --git a/package/gluon-ebtables-limit-arp/Makefile b/package/gluon-ebtables-limit-arp/Makefile
new file mode 100644
index 00000000..a722e0d5
--- /dev/null
+++ b/package/gluon-ebtables-limit-arp/Makefile
@@ -0,0 +1,59 @@
+include $(TOPDIR)/rules.mk
+
+PKG_NAME:=gluon-ebtables-limit-arp
+PKG_VERSION:=1
+PKG_RELEASE:=1
+
+PKG_BUILD_DIR := $(BUILD_DIR)/$(PKG_NAME)
+
+include $(INCLUDE_DIR)/package.mk
+
+define Package/gluon-ebtables-limit-arp
+ SECTION:=gluon
+ CATEGORY:=Gluon
+ TITLE:=Ebtables limiter for ARP packets
+ DEPENDS:=+gluon-core +gluon-ebtables gluon-mesh-batman-adv
+endef
+
+define Package/gluon-ebtables-limit-arp/description
+ Gluon community wifi mesh firmware framework: Ebtables rules to
+ rate-limit ARP packets.
+
+ This package adds filters to limit the amount of ARP Requests
+ devices are allowed to send into the mesh. The limits are 6 packets
+ per minute per client device, by MAC address, and 1 per second per
+ node in total.
+
+ A burst of up to 50 ARP Requests is allowed until the rate-limiting
+ takes effect (see --limit-burst in the ebtables manpage).
+
+ Furthermore, ARP Requests with a target IP already present in the
+ batman-adv DAT Cache are excluded from the rate-limiting,
+ both regarding counting and filtering, as batman-adv will respond
+ locally with no burden for the mesh. Therefore, this limiter
+ should not affect popular target IPs, like gateways.
+
+ However it should mitigate the problem of curious people or
+ smart devices scanning the whole IP range. Which could create
+ a significant amount of overhead for all participants so far.
+endef
+
+define Build/Prepare
+ mkdir -p $(PKG_BUILD_DIR)
+ $(CP) ./src/* $(PKG_BUILD_DIR)/
+endef
+
+define Build/Configure
+endef
+
+define Build/Compile
+ $(call Build/Compile/Default)
+endef
+
+define Package/gluon-ebtables-limit-arp/install
+ $(CP) ./files/* $(1)/
+ $(INSTALL_DIR) $(1)/usr/sbin/
+ $(CP) $(PKG_BUILD_DIR)/gluon-arp-limiter $(1)/usr/sbin/gluon-arp-limiter
+endef
+
+$(eval $(call BuildPackage,gluon-ebtables-limit-arp))
diff --git a/package/gluon-ebtables-limit-arp/files/etc/init.d/gluon-arp-limiter b/package/gluon-ebtables-limit-arp/files/etc/init.d/gluon-arp-limiter
new file mode 100755
index 00000000..553b4e20
--- /dev/null
+++ b/package/gluon-ebtables-limit-arp/files/etc/init.d/gluon-arp-limiter
@@ -0,0 +1,14 @@
+#!/bin/sh /etc/rc.common
+
+USE_PROCD=1
+START=20
+STOP=90
+
+start_service() {
+ procd_open_instance
+ procd_set_param command /usr/sbin/gluon-arp-limiter
+ procd_set_param respawn ${respawn_threshold:-3600} ${respawn_timeout:-5} ${respawn_retry:-5}
+
+ procd_set_param stderr 1
+ procd_close_instance
+}
diff --git a/package/gluon-ebtables-limit-arp/files/lib/gluon/ebtables/100-arp-limit-chains b/package/gluon-ebtables-limit-arp/files/lib/gluon/ebtables/100-arp-limit-chains
new file mode 100644
index 00000000..b39b35c8
--- /dev/null
+++ b/package/gluon-ebtables-limit-arp/files/lib/gluon/ebtables/100-arp-limit-chains
@@ -0,0 +1,3 @@
+chain('ARP_LIMIT', 'DROP')
+chain('ARP_LIMIT_DATCHECK', 'RETURN')
+chain('ARP_LIMIT_TLCHECK', 'RETURN')
diff --git a/package/gluon-ebtables-limit-arp/files/lib/gluon/ebtables/320-arp-limit-rules b/package/gluon-ebtables-limit-arp/files/lib/gluon/ebtables/320-arp-limit-rules
new file mode 100644
index 00000000..416bdd96
--- /dev/null
+++ b/package/gluon-ebtables-limit-arp/files/lib/gluon/ebtables/320-arp-limit-rules
@@ -0,0 +1,6 @@
+rule('ARP_LIMIT -j ARP_LIMIT_DATCHECK')
+rule('ARP_LIMIT --mark 0x2/0x2 -j RETURN')
+rule('ARP_LIMIT -j ARP_LIMIT_TLCHECK')
+rule('ARP_LIMIT --limit 1/sec --limit-burst 50 -j RETURN')
+
+rule('FORWARD -p ARP --logical-out br-client -o bat0 --arp-op Request -j ARP_LIMIT')
diff --git a/package/gluon-ebtables-limit-arp/src/LICENSE b/package/gluon-ebtables-limit-arp/src/LICENSE
new file mode 100644
index 00000000..d159169d
--- /dev/null
+++ b/package/gluon-ebtables-limit-arp/src/LICENSE
@@ -0,0 +1,339 @@
+ GNU GENERAL PUBLIC LICENSE
+ Version 2, June 1991
+
+ Copyright (C) 1989, 1991 Free Software Foundation, Inc.,
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diff --git a/package/gluon-ebtables-limit-arp/src/Makefile b/package/gluon-ebtables-limit-arp/src/Makefile
new file mode 100644
index 00000000..8d361c77
--- /dev/null
+++ b/package/gluon-ebtables-limit-arp/src/Makefile
@@ -0,0 +1,14 @@
+# Copyright (c) 2017 Linus Lüssing <linus.luessing@c0d3.blue>
+#
+# SPDX-License-Identifier: GPL-2.0+
+# License-Filename: LICENSE
+
+all: gluon-arp-limiter
+
+CFLAGS += -Wall
+
+gluon-arp-limiter: gluon-arp-limiter.c addr_store.c lookup3.c mac.c
+ $(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) -fPIC -D_GNU_SOURCE -o $@ $^ $(LDLIBS)
+
+clean:
+ rm -f gluon-arp-limiter
diff --git a/package/gluon-ebtables-limit-arp/src/addr_store.c b/package/gluon-ebtables-limit-arp/src/addr_store.c
new file mode 100644
index 00000000..1eb4aef6
--- /dev/null
+++ b/package/gluon-ebtables-limit-arp/src/addr_store.c
@@ -0,0 +1,167 @@
+/*
+ * Copyright (c) 2017 Linus Lüssing <linus.luessing@c0d3.blue>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ * License-Filename: LICENSE
+ */
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "addr_store.h"
+#include "gluon-arp-limiter.h"
+#include "lookup3.h"
+
+static struct addr_list *addr_node_alloc(void *addr,
+ struct addr_store *store)
+{
+ struct addr_list *node;
+ size_t addr_len = store->addr_len;
+
+ node = malloc(sizeof(struct addr_list) + addr_len);
+ if (!node)
+ return NULL;
+
+ memcpy(node->addr, addr, addr_len);
+ node->next = NULL;
+ node->tic = clock;
+
+ return node;
+}
+
+static struct addr_list *addr_list_search(void *addr,
+ size_t addr_len,
+ struct addr_list *list)
+{
+ struct addr_list *node = list;
+ struct addr_list *ret = NULL;
+
+ if (!node)
+ goto out;
+
+ do {
+ // Found it!
+ if (!memcmp(node->addr, addr, addr_len)) {
+ ret = node;
+ break;
+ }
+
+ node = node->next;
+ } while (node);
+
+out:
+ return ret;
+}
+
+static void addr_list_add(struct addr_list *node, struct addr_list **list)
+{
+ node->next = *list;
+ *list = node;
+}
+
+static struct addr_list **addr_store_get_bucket(void *addr,
+ struct addr_store *store)
+{
+ int len = store->addr_len / sizeof(uint32_t);
+ int idx;
+ uint32_t ret;
+
+ ret = hashword(addr, len, 0);
+ idx = ret % ADDR_STORE_NUM_BUCKETS;
+
+ return &store->buckets[idx];
+}
+
+int addr_store_add(void *addr, struct addr_store *store)
+{
+ struct addr_list **bucket = addr_store_get_bucket(addr, store);
+ struct addr_list *node = addr_list_search(addr, store->addr_len,
+ *bucket);
+
+ if (node) {
+ node->tic = clock;
+ return -EEXIST;
+ }
+
+ node = addr_node_alloc(addr, store);
+ if (!node) {
+ printf("Error: Out of memory\n");
+ return -ENOMEM;
+ }
+
+ addr_list_add(node, bucket);
+ return 0;
+}
+
+int addr_store_init(size_t addr_len,
+ void (*destructor)(struct addr_list *),
+ char *(*ntoa)(void *),
+ struct addr_store *store)
+{
+ int i;
+
+ store->addr_len = addr_len;
+ store->destructor = destructor;
+ store->ntoa = ntoa;
+
+ for (i = 0; i < ADDR_STORE_NUM_BUCKETS; i++)
+ store->buckets[i] = NULL;
+
+ return 0;
+}
+
+static char *addr_ntoa(void *addr, struct addr_store *store)
+{
+ return store->ntoa(addr);
+}
+
+static void addr_store_dump(struct addr_store *store)
+{
+ int i;
+ struct addr_list *node;
+
+ for (i = 0; i < ADDR_STORE_NUM_BUCKETS; i++) {
+ node = store->buckets[i];
+
+ if (node)
+ printf("Bucket #%i:\n", i);
+
+ while (node) {
+ printf("\t%s\n", addr_ntoa(node->addr, store));
+ node = node->next;
+ }
+ }
+}
+
+void addr_store_cleanup(struct addr_store *store)
+{
+ struct addr_list *node, *prev;
+ int i;
+
+ for (i = 0; i < ADDR_STORE_NUM_BUCKETS; i++) {
+ node = store->buckets[i];
+ prev = NULL;
+
+ while (node) {
+ if (node->tic != clock) {
+ store->destructor(node);
+
+ if (prev) {
+ prev->next = node->next;
+ free(node);
+ node = prev->next;
+ } else {
+ store->buckets[i] = node->next;
+ free(node);
+ node = store->buckets[i];
+ }
+ } else {
+ prev = node;
+ node = node->next;
+ }
+ }
+ }
+
+ addr_store_dump(store);
+}
diff --git a/package/gluon-ebtables-limit-arp/src/addr_store.h b/package/gluon-ebtables-limit-arp/src/addr_store.h
new file mode 100644
index 00000000..d3eaa78d
--- /dev/null
+++ b/package/gluon-ebtables-limit-arp/src/addr_store.h
@@ -0,0 +1,33 @@
+/*
+ * Copyright (c) 2017 Linus Lüssing <linus.luessing@c0d3.blue>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ * License-Filename: LICENSE
+ */
+
+#ifndef _ADDR_STORE_H_
+#define _ADDR_STORE_H_
+
+#define ADDR_STORE_NUM_BUCKETS 32
+
+struct addr_list {
+ struct addr_list *next;
+ int tic;
+ char addr[0];
+};
+
+struct addr_store {
+ struct addr_list *buckets[ADDR_STORE_NUM_BUCKETS];
+ size_t addr_len;
+ void (*destructor)(struct addr_list *);
+ char *(*ntoa)(void *);
+};
+
+int addr_store_init(size_t addr_len,
+ void (*destructor)(struct addr_list *),
+ char *(*ntoa)(void *),
+ struct addr_store *store);
+int addr_store_add(void *addr, struct addr_store *store);
+void addr_store_cleanup(struct addr_store *store);
+
+#endif /* _ADDR_STORE_H_ */
diff --git a/package/gluon-ebtables-limit-arp/src/gluon-arp-limiter.c b/package/gluon-ebtables-limit-arp/src/gluon-arp-limiter.c
new file mode 100644
index 00000000..cbb6faf2
--- /dev/null
+++ b/package/gluon-ebtables-limit-arp/src/gluon-arp-limiter.c
@@ -0,0 +1,302 @@
+/*
+ * Copyright (c) 2017 Linus Lüssing <linus.luessing@c0d3.blue>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ * License-Filename: LICENSE
+ */
+
+#include <arpa/inet.h>
+#include <errno.h>
+#include <netinet/in.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include "addr_store.h"
+#include "gluon-arp-limiter.h"
+#include "mac.h"
+
+#define BATCTL_DC "/usr/sbin/batctl dc -H -n"
+#define BATCTL_TL "/usr/sbin/batctl tl -H -n"
+#define EBTABLES "/usr/sbin/ebtables --concurrent"
+
+#define BUILD_BUG_ON(check) ((void)sizeof(int[1-2*!!(check)]))
+
+static struct addr_store ip_store;
+static struct addr_store mac_store;
+
+char *addr_mac_ntoa(void *addr)
+{
+ return mac_ntoa((struct mac_addr *)addr);
+}
+
+char *addr_inet_ntoa(void *addr)
+{
+ return inet_ntoa(*((struct in_addr *)addr));
+}
+
+static void ebt_ip_call(char *mod, struct in_addr ip)
+{
+ char str[196];
+ int ret;
+
+ snprintf(str, sizeof(str),
+ EBTABLES " %s ARP_LIMIT_DATCHECK -p ARP --arp-ip-dst %s -j mark --mark-or 0x2 --mark-target RETURN",
+ mod, inet_ntoa(ip));
+
+ ret = system(str);
+ if (ret)
+ fprintf(stderr,
+ "%i: Calling ebtables for DAT failed with status %i\n",
+ clock, ret);
+}
+
+static void ip_node_destructor(struct addr_list *node)
+{
+ struct in_addr *ip = (struct in_addr *)node->addr;
+
+ ebt_ip_call("-D", *ip);
+}
+
+static void ebt_mac_limit_call(char *mod, struct mac_addr *mac)
+{
+ char str[128];
+ int ret;
+
+ snprintf(str, sizeof(str),
+ EBTABLES " %s ARP_LIMIT_TLCHECK --source %s --limit 6/min --limit-burst 50 -j RETURN",
+ mod, mac_ntoa(mac));
+
+ ret = system(str);
+ if (ret)
+ fprintf(stderr,
+ "%i: Calling ebtables for TL failed with status %i\n",
+ clock, ret);
+}
+
+static void ebt_mac_ret_call(char *mod, struct mac_addr *mac, int add)
+{
+ char str[128];
+ int ret;
+
+ snprintf(str, sizeof(str),
+ EBTABLES " %s ARP_LIMIT_TLCHECK %s --source %s -j DROP",
+ mod, add ? "2" : "", mac_ntoa(mac));
+
+ ret = system(str);
+ if (ret)
+ fprintf(stderr,
+ "%i: Calling ebtables for TL failed with status %i\n",
+ clock, ret);
+}
+
+static void ebt_mac_call(char *mod, struct mac_addr *mac)
+{
+ if (!strncmp(mod, "-D", strlen(mod))) {
+ ebt_mac_ret_call(mod, mac, 0);
+ ebt_mac_limit_call(mod, mac);
+ } else {
+ ebt_mac_limit_call(mod, mac);
+ ebt_mac_ret_call(mod, mac, 1);
+ }
+}
+
+static void mac_node_destructor(struct addr_list *node)
+{
+ struct mac_addr *mac = (struct mac_addr *)node->addr;
+
+ ebt_mac_call("-D", mac);
+}
+
+static int dat_parse_line(const char *line, struct in_addr *ip)
+{
+ int ret;
+ char *p;
+ char *tok;
+
+ p = strpbrk(line, "0123456789");
+ if (!p) {
+ fprintf(stderr, "Error: Can't find integer in: %s\n", line);
+ return -EINVAL;
+ }
+
+ tok = strtok(p, " ");
+ if (!tok) {
+ fprintf(stderr, "Error: Can't find end of string': %s\n", line);
+ return -EINVAL;
+ }
+
+ ret = inet_aton(p, ip);
+ if (!ret) {
+ fprintf(stderr, "Error: inet_aton failed on: %s\n", p);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static void ebt_add_ip(struct in_addr ip)
+{
+ int ret = addr_store_add(&ip, &ip_store);
+
+ /* already stored or out-of-memory */
+ if (ret)
+ return;
+
+ ebt_ip_call("-I", ip);
+}
+
+static void ebt_add_mac(struct mac_addr *mac)
+{
+ int ret = addr_store_add(mac, &mac_store);
+
+ /* already stored or out-of-memory */
+ if (ret)
+ return;
+
+ ebt_mac_call("-I", mac);
+}
+
+static void ebt_dat_update(void)
+{
+ FILE *fp;
+ char line[256];
+ char *pline;
+ int ret;
+ struct in_addr ip;
+
+ fp = popen(BATCTL_DC, "r");
+ if (!fp) {
+ fprintf(stderr, "%i: Error: Could not call batctl dc\n", clock);
+ return;
+ }
+
+ while (1) {
+ pline = fgets(line, sizeof(line), fp);
+ if (!pline) {
+ if (!feof(fp))
+ fprintf(stderr, "%i: Error: fgets() failed\n", clock);
+ break;
+ }
+
+ ret = dat_parse_line(line, &ip);
+ if (ret < 0) {
+ fprintf(stderr, "%i: Error: Parsing line failed\n",
+ clock);
+ break;
+ }
+
+ ebt_add_ip(ip);
+ }
+
+ pclose(fp);
+}
+
+static int tl_parse_line(char *line, struct mac_addr *mac)
+{
+ int ret;
+ char *p;
+ char *tok;
+
+ p = strpbrk(line, "0123456789abcdef");
+ if (!p) {
+ fprintf(stderr, "Error: Can't find hex in: %s\n", line);
+ return -EINVAL;
+ }
+
+ tok = strtok(p, " ");
+ if (!tok) {
+ fprintf(stderr, "Error: Can't find end of string': %s\n", line);
+ return -EINVAL;
+ }
+
+ ret = mac_aton(p, mac);
+ if (!ret) {
+ fprintf(stderr, "Error: mac_aton failed on: %s\n", p);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static void ebt_tl_update(void)
+{
+ FILE *fp;
+ char line[256];
+ char *pline;
+ int ret;
+ struct mac_addr mac;
+
+ fp = popen(BATCTL_TL, "r");
+ if (!fp) {
+ fprintf(stderr, "%i: Error: Could not call batctl tl\n", clock);
+ return;
+ }
+
+ while (1) {
+ pline = fgets(line, sizeof(line), fp);
+ if (!pline) {
+ if (!feof(fp))
+ fprintf(stderr, "%i: Error: fgets() failed\n", clock);
+ break;
+ }
+
+ ret = tl_parse_line(line, &mac);
+ if (ret < 0) {
+ fprintf(stderr, "%i: Error: Parsing line failed\n",
+ clock);
+ break;
+ }
+
+ if (mac_is_multicast(&mac))
+ continue;
+
+ ebt_add_mac(&mac);
+ }
+
+ pclose(fp);
+}
+
+static void ebt_dat_flush(void)
+{
+ int ret = system(EBTABLES " -F ARP_LIMIT_DATCHECK");
+
+ if (ret)
+ fprintf(stderr, "Error flushing ARP_LIMIT_DATCHECK\n");
+}
+
+static void ebt_tl_flush(void)
+{
+ int ret = system(EBTABLES " -F ARP_LIMIT_TLCHECK");
+
+ if (ret)
+ fprintf(stderr, "Error flushing ARP_LIMIT_TLCHECK\n");
+}
+
+int main(int argc, char *argv[])
+{
+ ebt_dat_flush();
+ ebt_tl_flush();
+
+ /* necessary alignment for hashword() */
+ BUILD_BUG_ON(sizeof(struct in_addr) % sizeof(uint32_t) != 0);
+ BUILD_BUG_ON(sizeof(struct mac_addr) % sizeof(uint32_t) != 0);
+
+ addr_store_init(sizeof(struct in_addr), &ip_node_destructor,
+ addr_inet_ntoa, &ip_store);
+ addr_store_init(sizeof(struct mac_addr), &mac_node_destructor,
+ addr_mac_ntoa, &mac_store);
+
+ while (1) {
+ ebt_dat_update();
+ addr_store_cleanup(&ip_store);
+
+ ebt_tl_update();
+ addr_store_cleanup(&mac_store);
+
+ sleep(30);
+ clock++;
+ }
+
+ return 0;
+}
diff --git a/package/gluon-ebtables-limit-arp/src/gluon-arp-limiter.h b/package/gluon-ebtables-limit-arp/src/gluon-arp-limiter.h
new file mode 100644
index 00000000..203ab217
--- /dev/null
+++ b/package/gluon-ebtables-limit-arp/src/gluon-arp-limiter.h
@@ -0,0 +1,13 @@
+/*
+ * Copyright (c) 2017 Linus Lüssing <linus.luessing@c0d3.blue>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ * License-Filename: LICENSE
+ */
+
+#ifndef _GLUON_ARP_LIMITER_H_
+#define _GLUON_ARP_LIMITER_H_
+
+int clock;
+
+#endif /* _GLUON_ARP_LIMITER_H_ */
diff --git a/package/gluon-ebtables-limit-arp/src/lookup3.c b/package/gluon-ebtables-limit-arp/src/lookup3.c
new file mode 100644
index 00000000..a6252a92
--- /dev/null
+++ b/package/gluon-ebtables-limit-arp/src/lookup3.c
@@ -0,0 +1,998 @@
+/*
+-------------------------------------------------------------------------------
+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.
+
+You probably want to use hashlittle(). hashlittle() and hashbig()
+hash byte arrays. hashlittle() is is faster than hashbig() on
+little-endian machines. Intel and AMD are little-endian machines.
+On second thought, you probably want hashlittle2(), which is identical to
+hashlittle() except it returns two 32-bit hashes for the price of one.
+You could implement hashbig2() if you wanted but I haven't bothered here.
+
+If you want to find a hash of, say, exactly 7 integers, do
+ a = i1; b = i2; c = i3;
+ mix(a,b,c);
+ a += i4; b += i5; c += i6;
+ mix(a,b,c);
+ a += i7;
+ final(a,b,c);
+then use c as the hash value. If you have a variable length array of
+4-byte integers to hash, use hashword(). If you have a byte array (like
+a character string), use hashlittle(). If you have several byte arrays, or
+a mix of things, see the comments above hashlittle().
+
+Why is this so big? I read 12 bytes at a time into 3 4-byte integers,
+then mix those integers. This is fast (you can do a lot more thorough
+mixing with 12*3 instructions on 3 integers than you can with 3 instructions
+on 1 byte), but shoehorning those bytes into integers efficiently is messy.
+-------------------------------------------------------------------------------
+*/
+//#define SELF_TEST 1
+
+#include <stdio.h> /* defines printf for tests */
+#include <time.h> /* defines time_t for timings in the test */
+#include <stdint.h> /* defines uint32_t etc */
+#include <sys/param.h> /* attempt to define endianness */
+#ifdef linux
+# include <endian.h> /* attempt to define endianness */
+#endif
+
+/*
+ * My best guess at if you are big-endian or little-endian. This may
+ * need adjustment.
+ */
+#if (defined(__BYTE_ORDER) && defined(__LITTLE_ENDIAN) && \
+ __BYTE_ORDER == __LITTLE_ENDIAN) || \
+ (defined(i386) || defined(__i386__) || defined(__i486__) || \
+ defined(__i586__) || defined(__i686__) || defined(vax) || defined(MIPSEL))
+# define HASH_LITTLE_ENDIAN 1
+# define HASH_BIG_ENDIAN 0
+#elif (defined(__BYTE_ORDER) && defined(__BIG_ENDIAN) && \
+ __BYTE_ORDER == __BIG_ENDIAN) || \
+ (defined(sparc) || defined(POWERPC) || defined(mc68000) || defined(sel))
+# define HASH_LITTLE_ENDIAN 0
+# define HASH_BIG_ENDIAN 1
+#else
+# define HASH_LITTLE_ENDIAN 0
+# define HASH_BIG_ENDIAN 0
+#endif
+
+#define hashsize(n) ((uint32_t)1<<(n))
+#define hashmask(n) (hashsize(n)-1)
+#define rot(x,k) (((x)<<(k)) | ((x)>>(32-(k))))
+
+/*
+-------------------------------------------------------------------------------
+mix -- mix 3 32-bit values reversibly.
+
+This is reversible, so any information in (a,b,c) before mix() is
+still in (a,b,c) after mix().
+
+If four pairs of (a,b,c) inputs are run through mix(), or through
+mix() in reverse, there are at least 32 bits of the output that
+are sometimes the same for one pair and different for another pair.
+This was tested for:
+* pairs that differed by one bit, by two bits, in any combination
+ of top bits of (a,b,c), or in any combination of bottom bits of
+ (a,b,c).
+* "differ" is defined as +, -, ^, or ~^. For + and -, I transformed
+ the output delta to a Gray code (a^(a>>1)) so a string of 1's (as
+ is commonly produced by subtraction) look like a single 1-bit
+ difference.
+* the base values were pseudorandom, all zero but one bit set, or
+ all zero plus a counter that starts at zero.
+
+Some k values for my "a-=c; a^=rot(c,k); c+=b;" arrangement that
+satisfy this are
+ 4 6 8 16 19 4
+ 9 15 3 18 27 15
+ 14 9 3 7 17 3
+Well, "9 15 3 18 27 15" didn't quite get 32 bits diffing
+for "differ" defined as + with a one-bit base and a two-bit delta. I
+used http://burtleburtle.net/bob/hash/avalanche.html to choose
+the operations, constants, and arrangements of the variables.
+
+This does not achieve avalanche. There are input bits of (a,b,c)
+that fail to affect some output bits of (a,b,c), especially of a. The
+most thoroughly mixed value is c, but it doesn't really even achieve
+avalanche in c.
+
+This allows some parallelism. Read-after-writes are good at doubling
+the number of bits affected, so the goal of mixing pulls in the opposite
+direction as the goal of parallelism. I did what I could. Rotates
+seem to cost as much as shifts on every machine I could lay my hands
+on, and rotates are much kinder to the top and bottom bits, so I used
+rotates.
+-------------------------------------------------------------------------------
+*/
+#define mix(a,b,c) \
+{ \
+ a -= c; a ^= rot(c, 4); c += b; \
+ b -= a; b ^= rot(a, 6); a += c; \
+ c -= b; c ^= rot(b, 8); b += a; \
+ a -= c; a ^= rot(c,16); c += b; \
+ b -= a; b ^= rot(a,19); a += c; \
+ c -= b; c ^= rot(b, 4); b += a; \
+}
+
+/*
+-------------------------------------------------------------------------------
+final -- final mixing of 3 32-bit values (a,b,c) into c
+
+Pairs of (a,b,c) values differing in only a few bits will usually
+produce values of c that look totally different. This was tested for
+* pairs that differed by one bit, by two bits, in any combination
+ of top bits of (a,b,c), or in any combination of bottom bits of
+ (a,b,c).
+* "differ" is defined as +, -, ^, or ~^. For + and -, I transformed
+ the output delta to a Gray code (a^(a>>1)) so a string of 1's (as
+ is commonly produced by subtraction) look like a single 1-bit
+ difference.
+* the base values were pseudorandom, all zero but one bit set, or
+ all zero plus a counter that starts at zero.
+
+These constants passed:
+ 14 11 25 16 4 14 24
+ 12 14 25 16 4 14 24
+and these came close:
+ 4 8 15 26 3 22 24
+ 10 8 15 26 3 22 24
+ 11 8 15 26 3 22 24
+-------------------------------------------------------------------------------
+*/
+#define final(a,b,c) \
+{ \
+ c ^= b; c -= rot(b,14); \
+ a ^= c; a -= rot(c,11); \
+ b ^= a; b -= rot(a,25); \
+ c ^= b; c -= rot(b,16); \
+ a ^= c; a -= rot(c,4); \
+ b ^= a; b -= rot(a,14); \
+ c ^= b; c -= rot(b,24); \
+}
+
+/*
+--------------------------------------------------------------------
+ This works on all machines. To be useful, it requires
+ -- that the key be an array of uint32_t's, and
+ -- that the length be the number of uint32_t's in the key
+
+ The function hashword() is identical to hashlittle() on little-endian
+ machines, and identical to hashbig() on big-endian machines,
+ except that the length has to be measured in uint32_ts rather than in
+ bytes. hashlittle() is more complicated than hashword() only because
+ hashlittle() has to dance around fitting the key bytes into registers.
+--------------------------------------------------------------------
+*/
+uint32_t hashword(
+const uint32_t *k, /* the key, an array of uint32_t values */
+size_t length, /* the length of the key, in uint32_ts */
+uint32_t initval) /* the previous hash, or an arbitrary value */
+{
+ uint32_t a,b,c;
+
+ /* Set up the internal state */
+ a = b = c = 0xdeadbeef + (((uint32_t)length)<<2) + initval;
+
+ /*------------------------------------------------- handle most of the key */
+ while (length > 3)
+ {
+ a += k[0];
+ b += k[1];
+ c += k[2];
+ mix(a,b,c);
+ length -= 3;
+ k += 3;
+ }
+
+ /*------------------------------------------- handle the last 3 uint32_t's */
+ switch(length) /* all the case statements fall through */
+ {
+ case 3 : c+=k[2];
+ case 2 : b+=k[1];
+ case 1 : a+=k[0];
+ final(a,b,c);
+ case 0: /* case 0: nothing left to add */
+ break;
+ }
+ /*------------------------------------------------------ report the result */
+ return c;
+}
+
+
+/*
+--------------------------------------------------------------------
+hashword2() -- same as hashword(), but take two seeds and return two
+32-bit values. pc and pb must both be nonnull, and *pc and *pb must
+both be initialized with seeds. If you pass in (*pb)==0, the output
+(*pc) will be the same as the return value from hashword().
+--------------------------------------------------------------------
+*/
+void hashword2 (
+const uint32_t *k, /* the key, an array of uint32_t values */
+size_t length, /* the length of the key, in uint32_ts */
+uint32_t *pc, /* IN: seed OUT: primary hash value */
+uint32_t *pb) /* IN: more seed OUT: secondary hash value */
+{
+ uint32_t a,b,c;
+
+ /* Set up the internal state */
+ a = b = c = 0xdeadbeef + ((uint32_t)(length<<2)) + *pc;
+ c += *pb;
+
+ /*------------------------------------------------- handle most of the key */
+ while (length > 3)
+ {
+ a += k[0];
+ b += k[1];
+ c += k[2];
+ mix(a,b,c);
+ length -= 3;
+ k += 3;
+ }
+
+ /*------------------------------------------- handle the last 3 uint32_t's */
+ switch(length) /* all the case statements fall through */
+ {
+ case 3 : c+=k[2];
+ case 2 : b+=k[1];
+ case 1 : a+=k[0];
+ final(a,b,c);
+ case 0: /* case 0: nothing left to add */
+ break;
+ }
+ /*------------------------------------------------------ report the result */
+ *pc=c; *pb=b;
+}
+
+
+/*
+-------------------------------------------------------------------------------
+hashlittle() -- hash a variable-length key into a 32-bit value
+ k : the key (the unaligned variable-length array of bytes)
+ length : the length of the key, counting by bytes
+ initval : can be any 4-byte value
+Returns a 32-bit value. Every bit of the key affects every bit of
+the return value. Two keys differing by one or two bits will have
+totally different hash values.
+
+The best hash table sizes are powers of 2. There is no need to do
+mod a prime (mod is sooo slow!). If you need less than 32 bits,
+use a bitmask. For example, if you need only 10 bits, do
+ h = (h & hashmask(10));
+In which case, the hash table should have hashsize(10) elements.
+
+If you are hashing n strings (uint8_t **)k, do it like this:
+ for (i=0, h=0; i<n; ++i) h = hashlittle( k[i], len[i], h);
+
+By Bob Jenkins, 2006. bob_jenkins@burtleburtle.net. You may use this
+code any way you wish, private, educational, or commercial. It's free.
+
+Use for hash table lookup, or anything where one collision in 2^^32 is
+acceptable. Do NOT use for cryptographic purposes.
+-------------------------------------------------------------------------------
+*/
+
+uint32_t hashlittle( const void *key, size_t length, uint32_t initval)
+{
+ uint32_t a,b,c; /* internal state */
+ union { const void *ptr; size_t i; } u; /* needed for Mac Powerbook G4 */
+
+ /* Set up the internal state */
+ a = b = c = 0xdeadbeef + ((uint32_t)length) + initval;
+
+ u.ptr = key;
+ if (HASH_LITTLE_ENDIAN && ((u.i & 0x3) == 0)) {
+ const uint32_t *k = (const uint32_t *)key; /* read 32-bit chunks */
+
+ /*------ all but last block: aligned reads and affect 32 bits of (a,b,c) */
+ while (length > 12)
+ {
+ a += k[0];
+ b += k[1];
+ c += k[2];
+ mix(a,b,c);
+ length -= 12;
+ k += 3;
+ }
+
+ /*----------------------------- handle the last (probably partial) block */
+ /*
+ * "k[2]&0xffffff" actually reads beyond the end of the string, but
+ * then masks off the part it's not allowed to read. Because the
+ * string is aligned, the masked-off tail is in the same word as the
+ * rest of the string. Every machine with memory protection I've seen
+ * does it on word boundaries, so is OK with this. But VALGRIND will
+ * still catch it and complain. The masking trick does make the hash
+ * noticably faster for short strings (like English words).
+ */
+#ifndef VALGRIND
+
+ switch(length)
+ {
+ case 12: c+=k[2]; b+=k[1]; a+=k[0]; break;
+ case 11: c+=k[2]&0xffffff; b+=k[1]; a+=k[0]; break;
+ case 10: c+=k[2]&0xffff; b+=k[1]; a+=k[0]; break;
+ case 9 : c+=k[2]&0xff; b+=k[1]; a+=k[0]; break;
+ case 8 : b+=k[1]; a+=k[0]; break;
+ case 7 : b+=k[1]&0xffffff; a+=k[0]; break;
+ case 6 : b+=k[1]&0xffff; a+=k[0]; break;
+ case 5 : b+=k[1]&0xff; a+=k[0]; break;
+ case 4 : a+=k[0]; break;
+ case 3 : a+=k[0]&0xffffff; break;
+ case 2 : a+=k[0]&0xffff; break;
+ case 1 : a+=k[0]&0xff; break;
+ case 0 : return c; /* zero length strings require no mixing */
+ }
+
+#else /* make valgrind happy */
+
+ k8 = (const uint8_t *)k;
+ switch(length)
+ {
+ case 12: c+=k[2]; b+=k[1]; a+=k[0]; break;
+ case 11: c+=((uint32_t)k8[10])<<16; /* fall through */
+ case 10: c+=((uint32_t)k8[9])<<8; /* fall through */
+ case 9 : c+=k8[8]; /* fall through */
+ case 8 : b+=k[1]; a+=k[0]; break;
+ case 7 : b+=((uint32_t)k8[6])<<16; /* fall through */
+ case 6 : b+=((uint32_t)k8[5])<<8; /* fall through */
+ case 5 : b+=k8[4]; /* fall through */
+ case 4 : a+=k[0]; break;
+ case 3 : a+=((uint32_t)k8[2])<<16; /* fall through */
+ case 2 : a+=((uint32_t)k8[1])<<8; /* fall through */
+ case 1 : a+=k8[0]; break;
+ case 0 : return c;
+ }
+
+#endif /* !valgrind */
+
+ } else if (HASH_LITTLE_ENDIAN && ((u.i & 0x1) == 0)) {
+ const uint16_t *k = (const uint16_t *)key; /* read 16-bit chunks */
+ const uint8_t *k8;
+
+ /*--------------- all but last block: aligned reads and different mixing */
+ while (length > 12)
+ {
+ a += k[0] + (((uint32_t)k[1])<<16);
+ b += k[2] + (((uint32_t)k[3])<<16);
+ c += k[4] + (((uint32_t)k[5])<<16);
+ mix(a,b,c);
+ length -= 12;
+ k += 6;
+ }
+
+ /*----------------------------- handle the last (probably partial) block */
+ k8 = (const uint8_t *)k;
+ switch(length)
+ {
+ case 12: c+=k[4]+(((uint32_t)k[5])<<16);
+ b+=k[2]+(((uint32_t)k[3])<<16);
+ a+=k[0]+(((uint32_t)k[1])<<16);
+ break;
+ case 11: c+=((uint32_t)k8[10])<<16; /* fall through */
+ case 10: c+=k[4];
+ b+=k[2]+(((uint32_t)k[3])<<16);
+ a+=k[0]+(((uint32_t)k[1])<<16);
+ break;
+ case 9 : c+=k8[8]; /* fall through */
+ case 8 : b+=k[2]+(((uint32_t)k[3])<<16);
+ a+=k[0]+(((uint32_t)k[1])<<16);
+ break;
+ case 7 : b+=((uint32_t)k8[6])<<16; /* fall through */
+ case 6 : b+=k[2];
+ a+=k[0]+(((uint32_t)k[1])<<16);
+ break;
+ case 5 : b+=k8[4]; /* fall through */
+ case 4 : a+=k[0]+(((uint32_t)k[1])<<16);
+ break;
+ case 3 : a+=((uint32_t)k8[2])<<16; /* fall through */
+ case 2 : a+=k[0];
+ break;
+ case 1 : a+=k8[0];
+ break;
+ case 0 : return c; /* zero length requires no mixing */
+ }
+
+ } else { /* need to read the key one byte at a time */
+ const uint8_t *k = (const uint8_t *)key;
+
+ /*--------------- all but the last block: affect some 32 bits of (a,b,c) */
+ while (length > 12)
+ {
+ a += k[0];
+ a += ((uint32_t)k[1])<<8;
+ a += ((uint32_t)k[2])<<16;
+ a += ((uint32_t)k[3])<<24;
+ b += k[4];
+ b += ((uint32_t)k[5])<<8;
+ b += ((uint32_t)k[6])<<16;
+ b += ((uint32_t)k[7])<<24;
+ c += k[8];
+ c += ((uint32_t)k[9])<<8;
+ c += ((uint32_t)k[10])<<16;
+ c += ((uint32_t)k[11])<<24;
+ mix(a,b,c);
+ length -= 12;
+ k += 12;
+ }
+
+ /*-------------------------------- last block: affect all 32 bits of (c) */
+ switch(length) /* all the case statements fall through */
+ {
+ 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];
+ break;
+ case 0 : return c;
+ }
+ }
+
+ final(a,b,c);
+ return c;
+}
+
+
+/*
+ * hashlittle2: return 2 32-bit hash values
+ *
+ * This is identical to hashlittle(), except it returns two 32-bit hash
+ * values instead of just one. This is good enough for hash table
+ * lookup with 2^^64 buckets, or if you want a second hash if you're not
+ * happy with the first, or if you want a probably-unique 64-bit ID for
+ * the key. *pc is better mixed than *pb, so use *pc first. If you want
+ * a 64-bit value do something like "*pc + (((uint64_t)*pb)<<32)".
+ */
+void hashlittle2(
+ const void *key, /* the key to hash */
+ size_t length, /* length of the key */
+ uint32_t *pc, /* IN: primary initval, OUT: primary hash */
+ uint32_t *pb) /* IN: secondary initval, OUT: secondary hash */
+{
+ uint32_t a,b,c; /* internal state */
+ union { const void *ptr; size_t i; } u; /* needed for Mac Powerbook G4 */
+
+ /* Set up the internal state */
+ a = b = c = 0xdeadbeef + ((uint32_t)length) + *pc;
+ c += *pb;
+
+ u.ptr = key;
+ if (HASH_LITTLE_ENDIAN && ((u.i & 0x3) == 0)) {
+ const uint32_t *k = (const uint32_t *)key; /* read 32-bit chunks */
+
+ /*------ all but last block: aligned reads and affect 32 bits of (a,b,c) */
+ while (length > 12)
+ {
+ a += k[0];
+ b += k[1];
+ c += k[2];
+ mix(a,b,c);
+ length -= 12;
+ k += 3;
+ }
+
+ /*----------------------------- handle the last (probably partial) block */
+ /*
+ * "k[2]&0xffffff" actually reads beyond the end of the string, but
+ * then masks off the part it's not allowed to read. Because the
+ * string is aligned, the masked-off tail is in the same word as the
+ * rest of the string. Every machine with memory protection I've seen
+ * does it on word boundaries, so is OK with this. But VALGRIND will
+ * still catch it and complain. The masking trick does make the hash
+ * noticably faster for short strings (like English words).
+ */
+#ifndef VALGRIND
+
+ switch(length)
+ {
+ case 12: c+=k[2]; b+=k[1]; a+=k[0]; break;
+ case 11: c+=k[2]&0xffffff; b+=k[1]; a+=k[0]; break;
+ case 10: c+=k[2]&0xffff; b+=k[1]; a+=k[0]; break;
+ case 9 : c+=k[2]&0xff; b+=k[1]; a+=k[0]; break;
+ case 8 : b+=k[1]; a+=k[0]; break;
+ case 7 : b+=k[1]&0xffffff; a+=k[0]; break;
+ case 6 : b+=k[1]&0xffff; a+=k[0]; break;
+ case 5 : b+=k[1]&0xff; a+=k[0]; break;
+ case 4 : a+=k[0]; break;
+ case 3 : a+=k[0]&0xffffff; break;
+ case 2 : a+=k[0]&0xffff; break;
+ case 1 : a+=k[0]&0xff; break;
+ case 0 : *pc=c; *pb=b; return; /* zero length strings require no mixing */
+ }
+
+#else /* make valgrind happy */
+
+ k8 = (const uint8_t *)k;
+ switch(length)
+ {
+ case 12: c+=k[2]; b+=k[1]; a+=k[0]; break;
+ case 11: c+=((uint32_t)k8[10])<<16; /* fall through */
+ case 10: c+=((uint32_t)k8[9])<<8; /* fall through */
+ case 9 : c+=k8[8]; /* fall through */
+ case 8 : b+=k[1]; a+=k[0]; break;
+ case 7 : b+=((uint32_t)k8[6])<<16; /* fall through */
+ case 6 : b+=((uint32_t)k8[5])<<8; /* fall through */
+ case 5 : b+=k8[4]; /* fall through */
+ case 4 : a+=k[0]; break;
+ case 3 : a+=((uint32_t)k8[2])<<16; /* fall through */
+ case 2 : a+=((uint32_t)k8[1])<<8; /* fall through */
+ case 1 : a+=k8[0]; break;
+ case 0 : *pc=c; *pb=b; return; /* zero length strings require no mixing */
+ }
+
+#endif /* !valgrind */
+
+ } else if (HASH_LITTLE_ENDIAN && ((u.i & 0x1) == 0)) {
+ const uint16_t *k = (const uint16_t *)key; /* read 16-bit chunks */
+ const uint8_t *k8;
+
+ /*--------------- all but last block: aligned reads and different mixing */
+ while (length > 12)
+ {
+ a += k[0] + (((uint32_t)k[1])<<16);
+ b += k[2] + (((uint32_t)k[3])<<16);
+ c += k[4] + (((uint32_t)k[5])<<16);
+ mix(a,b,c);
+ length -= 12;
+ k += 6;
+ }
+
+ /*----------------------------- handle the last (probably partial) block */
+ k8 = (const uint8_t *)k;
+ switch(length)
+ {
+ case 12: c+=k[4]+(((uint32_t)k[5])<<16);
+ b+=k[2]+(((uint32_t)k[3])<<16);
+ a+=k[0]+(((uint32_t)k[1])<<16);
+ break;
+ case 11: c+=((uint32_t)k8[10])<<16; /* fall through */
+ case 10: c+=k[4];
+ b+=k[2]+(((uint32_t)k[3])<<16);
+ a+=k[0]+(((uint32_t)k[1])<<16);
+ break;
+ case 9 : c+=k8[8]; /* fall through */
+ case 8 : b+=k[2]+(((uint32_t)k[3])<<16);
+ a+=k[0]+(((uint32_t)k[1])<<16);
+ break;
+ case 7 : b+=((uint32_t)k8[6])<<16; /* fall through */
+ case 6 : b+=k[2];
+ a+=k[0]+(((uint32_t)k[1])<<16);
+ break;
+ case 5 : b+=k8[4]; /* fall through */
+ case 4 : a+=k[0]+(((uint32_t)k[1])<<16);
+ break;
+ case 3 : a+=((uint32_t)k8[2])<<16; /* fall through */
+ case 2 : a+=k[0];
+ break;
+ case 1 : a+=k8[0];
+ break;
+ case 0 : *pc=c; *pb=b; return; /* zero length strings require no mixing */
+ }
+
+ } else { /* need to read the key one byte at a time */
+ const uint8_t *k = (const uint8_t *)key;
+
+ /*--------------- all but the last block: affect some 32 bits of (a,b,c) */
+ while (length > 12)
+ {
+ a += k[0];
+ a += ((uint32_t)k[1])<<8;
+ a += ((uint32_t)k[2])<<16;
+ a += ((uint32_t)k[3])<<24;
+ b += k[4];
+ b += ((uint32_t)k[5])<<8;
+ b += ((uint32_t)k[6])<<16;
+ b += ((uint32_t)k[7])<<24;
+ c += k[8];
+ c += ((uint32_t)k[9])<<8;
+ c += ((uint32_t)k[10])<<16;
+ c += ((uint32_t)k[11])<<24;
+ mix(a,b,c);
+ length -= 12;
+ k += 12;
+ }
+
+ /*-------------------------------- last block: affect all 32 bits of (c) */
+ switch(length) /* all the case statements fall through */
+ {
+ 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];
+ break;
+ case 0 : *pc=c; *pb=b; return; /* zero length strings require no mixing */
+ }
+ }
+
+ final(a,b,c);
+ *pc=c; *pb=b;
+}
+
+
+
+/*
+ * hashbig():
+ * This is the same as hashword() on big-endian machines. It is different
+ * from hashlittle() on all machines. hashbig() takes advantage of
+ * big-endian byte ordering.
+ */
+uint32_t hashbig( const void *key, size_t length, uint32_t initval)
+{
+ uint32_t a,b,c;
+ union { const void *ptr; size_t i; } u; /* to cast key to (size_t) happily */
+
+ /* Set up the internal state */
+ a = b = c = 0xdeadbeef + ((uint32_t)length) + initval;
+
+ u.ptr = key;
+ if (HASH_BIG_ENDIAN && ((u.i & 0x3) == 0)) {
+ const uint32_t *k = (const uint32_t *)key; /* read 32-bit chunks */
+
+ /*------ all but last block: aligned reads and affect 32 bits of (a,b,c) */
+ while (length > 12)
+ {
+ a += k[0];
+ b += k[1];
+ c += k[2];
+ mix(a,b,c);
+ length -= 12;
+ k += 3;
+ }
+
+ /*----------------------------- handle the last (probably partial) block */
+ /*
+ * "k[2]<<8" actually reads beyond the end of the string, but
+ * then shifts out the part it's not allowed to read. Because the
+ * string is aligned, the illegal read is in the same word as the
+ * rest of the string. Every machine with memory protection I've seen
+ * does it on word boundaries, so is OK with this. But VALGRIND will
+ * still catch it and complain. The masking trick does make the hash
+ * noticably faster for short strings (like English words).
+ */
+#ifndef VALGRIND
+
+ switch(length)
+ {
+ case 12: c+=k[2]; b+=k[1]; a+=k[0]; break;
+ case 11: c+=k[2]&0xffffff00; b+=k[1]; a+=k[0]; break;
+ case 10: c+=k[2]&0xffff0000; b+=k[1]; a+=k[0]; break;
+ case 9 : c+=k[2]&0xff000000; b+=k[1]; a+=k[0]; break;
+ case 8 : b+=k[1]; a+=k[0]; break;
+ case 7 : b+=k[1]&0xffffff00; a+=k[0]; break;
+ case 6 : b+=k[1]&0xffff0000; a+=k[0]; break;
+ case 5 : b+=k[1]&0xff000000; a+=k[0]; break;
+ case 4 : a+=k[0]; break;
+ case 3 : a+=k[0]&0xffffff00; break;
+ case 2 : a+=k[0]&0xffff0000; break;
+ case 1 : a+=k[0]&0xff000000; break;
+ case 0 : return c; /* zero length strings require no mixing */
+ }
+
+#else /* make valgrind happy */
+
+ k8 = (const uint8_t *)k;
+ switch(length) /* all the case statements fall through */
+ {
+ case 12: c+=k[2]; b+=k[1]; a+=k[0]; break;
+ case 11: c+=((uint32_t)k8[10])<<8; /* fall through */
+ case 10: c+=((uint32_t)k8[9])<<16; /* fall through */
+ case 9 : c+=((uint32_t)k8[8])<<24; /* fall through */
+ case 8 : b+=k[1]; a+=k[0]; break;
+ case 7 : b+=((uint32_t)k8[6])<<8; /* fall through */
+ case 6 : b+=((uint32_t)k8[5])<<16; /* fall through */
+ case 5 : b+=((uint32_t)k8[4])<<24; /* fall through */
+ case 4 : a+=k[0]; break;
+ case 3 : a+=((uint32_t)k8[2])<<8; /* fall through */
+ case 2 : a+=((uint32_t)k8[1])<<16; /* fall through */
+ case 1 : a+=((uint32_t)k8[0])<<24; break;
+ case 0 : return c;
+ }
+
+#endif /* !VALGRIND */
+
+ } else { /* need to read the key one byte at a time */
+ const uint8_t *k = (const uint8_t *)key;
+
+ /*--------------- all but the last block: affect some 32 bits of (a,b,c) */
+ while (length > 12)
+ {
+ a += ((uint32_t)k[0])<<24;
+ a += ((uint32_t)k[1])<<16;
+ a += ((uint32_t)k[2])<<8;
+ a += ((uint32_t)k[3]);
+ b += ((uint32_t)k[4])<<24;
+ b += ((uint32_t)k[5])<<16;
+ b += ((uint32_t)k[6])<<8;
+ b += ((uint32_t)k[7]);
+ c += ((uint32_t)k[8])<<24;
+ c += ((uint32_t)k[9])<<16;
+ c += ((uint32_t)k[10])<<8;
+ c += ((uint32_t)k[11]);
+ mix(a,b,c);
+ length -= 12;
+ k += 12;
+ }
+
+ /*-------------------------------- last block: affect all 32 bits of (c) */
+ switch(length) /* all the case statements fall through */
+ {
+ case 12: c+=k[11];
+ case 11: c+=((uint32_t)k[10])<<8;
+ case 10: c+=((uint32_t)k[9])<<16;
+ case 9 : c+=((uint32_t)k[8])<<24;
+ case 8 : b+=k[7];
+ case 7 : b+=((uint32_t)k[6])<<8;
+ case 6 : b+=((uint32_t)k[5])<<16;
+ case 5 : b+=((uint32_t)k[4])<<24;
+ case 4 : a+=k[3];
+ case 3 : a+=((uint32_t)k[2])<<8;
+ case 2 : a+=((uint32_t)k[1])<<16;
+ case 1 : a+=((uint32_t)k[0])<<24;
+ break;
+ case 0 : return c;
+ }
+ }
+
+ final(a,b,c);
+ return c;
+}
+
+
+#ifdef SELF_TEST
+
+/* used for timings */
+void driver1()
+{
+ uint8_t buf[256];
+ uint32_t i;
+ uint32_t h=0;
+ time_t a,z;
+
+ time(&a);
+ for (i=0; i<256; ++i) buf[i] = 'x';
+ for (i=0; i<1; ++i)
+ {
+ h = hashlittle(&buf[0],1,h);
+ }
+ time(&z);
+ if (z-a > 0) printf("time %d %.8x\n", z-a, h);
+}
+
+/* check that every input bit changes every output bit half the time */
+#define HASHSTATE 1
+#define HASHLEN 1
+#define MAXPAIR 60
+#define MAXLEN 70
+void driver2()
+{
+ uint8_t qa[MAXLEN+1], qb[MAXLEN+2], *a = &qa[0], *b = &qb[1];
+ uint32_t c[HASHSTATE], d[HASHSTATE], i=0, j=0, k, l, m=0, z;
+ uint32_t e[HASHSTATE],f[HASHSTATE],g[HASHSTATE],h[HASHSTATE];
+ uint32_t x[HASHSTATE],y[HASHSTATE];
+ uint32_t hlen;
+
+ printf("No more than %d trials should ever be needed \n",MAXPAIR/2);
+ for (hlen=0; hlen < MAXLEN; ++hlen)
+ {
+ z=0;
+ for (i=0; i<hlen; ++i) /*----------------------- for each input byte, */
+ {
+ for (j=0; j<8; ++j) /*------------------------ for each input bit, */
+ {
+ for (m=1; m<8; ++m) /*------------ for serveral possible initvals, */
+ {
+ for (l=0; l<HASHSTATE; ++l)
+ e[l]=f[l]=g[l]=h[l]=x[l]=y[l]=~((uint32_t)0);
+
+ /*---- check that every output bit is affected by that input bit */
+ for (k=0; k<MAXPAIR; k+=2)
+ {
+ uint32_t finished=1;
+ /* keys have one bit different */
+ for (l=0; l<hlen+1; ++l) {a[l] = b[l] = (uint8_t)0;}
+ /* have a and b be two keys differing in only one bit */
+ a[i] ^= (k<<j);
+ a[i] ^= (k>>(8-j));
+ c[0] = hashlittle(a, hlen, m);
+ b[i] ^= ((k+1)<<j);
+ b[i] ^= ((k+1)>>(8-j));
+ d[0] = hashlittle(b, hlen, m);
+ /* check every bit is 1, 0, set, and not set at least once */
+ for (l=0; l<HASHSTATE; ++l)
+ {
+ e[l] &= (c[l]^d[l]);
+ f[l] &= ~(c[l]^d[l]);
+ g[l] &= c[l];
+ h[l] &= ~c[l];
+ x[l] &= d[l];
+ y[l] &= ~d[l];
+ if (e[l]|f[l]|g[l]|h[l]|x[l]|y[l]) finished=0;
+ }
+ if (finished) break;
+ }
+ if (k>z) z=k;
+ if (k==MAXPAIR)
+ {
+ printf("Some bit didn't change: ");
+ printf("%.8x %.8x %.8x %.8x %.8x %.8x ",
+ e[0],f[0],g[0],h[0],x[0],y[0]);
+ printf("i %d j %d m %d len %d\n", i, j, m, hlen);
+ }
+ if (z==MAXPAIR) goto done;
+ }
+ }
+ }
+ done:
+ if (z < MAXPAIR)
+ {
+ printf("Mix success %2d bytes %2d initvals ",i,m);
+ printf("required %d trials\n", z/2);
+ }
+ }
+ printf("\n");
+}
+
+/* Check for reading beyond the end of the buffer and alignment problems */
+void driver3()
+{
+ uint8_t buf[MAXLEN+20], *b;
+ uint32_t len;
+ uint8_t q[] = "This is the time for all good men to come to the aid of their country...";
+ uint32_t h;
+ uint8_t qq[] = "xThis is the time for all good men to come to the aid of their country...";
+ uint32_t i;
+ uint8_t qqq[] = "xxThis is the time for all good men to come to the aid of their country...";
+ uint32_t j;
+ uint8_t qqqq[] = "xxxThis is the time for all good men to come to the aid of their country...";
+ uint32_t ref,x,y;
+ uint8_t *p;
+
+ printf("Endianness. These lines should all be the same (for values filled in):\n");
+ printf("%.8x %.8x %.8x\n",
+ hashword((const uint32_t *)q, (sizeof(q)-1)/4, 13),
+ hashword((const uint32_t *)q, (sizeof(q)-5)/4, 13),
+ hashword((const uint32_t *)q, (sizeof(q)-9)/4, 13));
+ p = q;
+ printf("%.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x\n",
+ hashlittle(p, sizeof(q)-1, 13), hashlittle(p, sizeof(q)-2, 13),
+ hashlittle(p, sizeof(q)-3, 13), hashlittle(p, sizeof(q)-4, 13),
+ hashlittle(p, sizeof(q)-5, 13), hashlittle(p, sizeof(q)-6, 13),
+ hashlittle(p, sizeof(q)-7, 13), hashlittle(p, sizeof(q)-8, 13),
+ hashlittle(p, sizeof(q)-9, 13), hashlittle(p, sizeof(q)-10, 13),
+ hashlittle(p, sizeof(q)-11, 13), hashlittle(p, sizeof(q)-12, 13));
+ p = &qq[1];
+ printf("%.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x\n",
+ hashlittle(p, sizeof(q)-1, 13), hashlittle(p, sizeof(q)-2, 13),
+ hashlittle(p, sizeof(q)-3, 13), hashlittle(p, sizeof(q)-4, 13),
+ hashlittle(p, sizeof(q)-5, 13), hashlittle(p, sizeof(q)-6, 13),
+ hashlittle(p, sizeof(q)-7, 13), hashlittle(p, sizeof(q)-8, 13),
+ hashlittle(p, sizeof(q)-9, 13), hashlittle(p, sizeof(q)-10, 13),
+ hashlittle(p, sizeof(q)-11, 13), hashlittle(p, sizeof(q)-12, 13));
+ p = &qqq[2];
+ printf("%.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x\n",
+ hashlittle(p, sizeof(q)-1, 13), hashlittle(p, sizeof(q)-2, 13),
+ hashlittle(p, sizeof(q)-3, 13), hashlittle(p, sizeof(q)-4, 13),
+ hashlittle(p, sizeof(q)-5, 13), hashlittle(p, sizeof(q)-6, 13),
+ hashlittle(p, sizeof(q)-7, 13), hashlittle(p, sizeof(q)-8, 13),
+ hashlittle(p, sizeof(q)-9, 13), hashlittle(p, sizeof(q)-10, 13),
+ hashlittle(p, sizeof(q)-11, 13), hashlittle(p, sizeof(q)-12, 13));
+ p = &qqqq[3];
+ printf("%.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x\n",
+ hashlittle(p, sizeof(q)-1, 13), hashlittle(p, sizeof(q)-2, 13),
+ hashlittle(p, sizeof(q)-3, 13), hashlittle(p, sizeof(q)-4, 13),
+ hashlittle(p, sizeof(q)-5, 13), hashlittle(p, sizeof(q)-6, 13),
+ hashlittle(p, sizeof(q)-7, 13), hashlittle(p, sizeof(q)-8, 13),
+ hashlittle(p, sizeof(q)-9, 13), hashlittle(p, sizeof(q)-10, 13),
+ hashlittle(p, sizeof(q)-11, 13), hashlittle(p, sizeof(q)-12, 13));
+ printf("\n");
+
+ /* check that hashlittle2 and hashlittle produce the same results */
+ i=47; j=0;
+ hashlittle2(q, sizeof(q), &i, &j);
+ if (hashlittle(q, sizeof(q), 47) != i)
+ printf("hashlittle2 and hashlittle mismatch\n");
+
+ /* check that hashword2 and hashword produce the same results */
+ len = 0xdeadbeef;
+ i=47, j=0;
+ hashword2(&len, 1, &i, &j);
+ if (hashword(&len, 1, 47) != i)
+ printf("hashword2 and hashword mismatch %x %x\n",
+ i, hashword(&len, 1, 47));
+
+ /* check hashlittle doesn't read before or after the ends of the string */
+ for (h=0, b=buf+1; h<8; ++h, ++b)
+ {
+ for (i=0; i<MAXLEN; ++i)
+ {
+ len = i;
+ for (j=0; j<i; ++j) *(b+j)=0;
+
+ /* these should all be equal */
+ ref = hashlittle(b, len, (uint32_t)1);
+ *(b+i)=(uint8_t)~0;
+ *(b-1)=(uint8_t)~0;
+ x = hashlittle(b, len, (uint32_t)1);
+ y = hashlittle(b, len, (uint32_t)1);
+ if ((ref != x) || (ref != y))
+ {
+ printf("alignment error: %.8x %.8x %.8x %d %d\n",ref,x,y,
+ h, i);
+ }
+ }
+ }
+}
+
+/* check for problems with nulls */
+ void driver4()
+{
+ uint8_t buf[1];
+ uint32_t h,i,state[HASHSTATE];
+
+
+ buf[0] = ~0;
+ for (i=0; i<HASHSTATE; ++i) state[i] = 1;
+ printf("These should all be different\n");
+ for (i=0, h=0; i<8; ++i)
+ {
+ h = hashlittle(buf, 0, h);
+ printf("%2ld 0-byte strings, hash is %.8x\n", i, h);
+ }
+}
+
+void driver5()
+{
+ uint32_t b,c;
+ b=0, c=0, hashlittle2("", 0, &c, &b);
+ printf("hash is %.8lx %.8lx\n", c, b); /* deadbeef deadbeef */
+ b=0xdeadbeef, c=0, hashlittle2("", 0, &c, &b);
+ printf("hash is %.8lx %.8lx\n", c, b); /* bd5b7dde deadbeef */
+ b=0xdeadbeef, c=0xdeadbeef, hashlittle2("", 0, &c, &b);
+ printf("hash is %.8lx %.8lx\n", c, b); /* 9c093ccd bd5b7dde */
+ b=0, c=0, hashlittle2("Four score and seven years ago", 30, &c, &b);
+ printf("hash is %.8lx %.8lx\n", c, b); /* 17770551 ce7226e6 */
+ b=1, c=0, hashlittle2("Four score and seven years ago", 30, &c, &b);
+ printf("hash is %.8lx %.8lx\n", c, b); /* e3607cae bd371de4 */
+ b=0, c=1, hashlittle2("Four score and seven years ago", 30, &c, &b);
+ printf("hash is %.8lx %.8lx\n", c, b); /* cd628161 6cbea4b3 */
+ c = hashlittle("Four score and seven years ago", 30, 0);
+ printf("hash is %.8lx\n", c); /* 17770551 */
+ c = hashlittle("Four score and seven years ago", 30, 1);
+ printf("hash is %.8lx\n", c); /* cd628161 */
+}
+
+
+int main()
+{
+ driver1(); /* test that the key is hashed: used for timings */
+ driver2(); /* test that whole key is hashed thoroughly */
+ driver3(); /* test that nothing but the key is hashed */
+ driver4(); /* test hashing multiple buffers (all buffers are null) */
+ driver5(); /* test the hash against known vectors */
+ return 1;
+}
+
+#endif /* SELF_TEST */
diff --git a/package/gluon-ebtables-limit-arp/src/lookup3.h b/package/gluon-ebtables-limit-arp/src/lookup3.h
new file mode 100644
index 00000000..321ad4b6
--- /dev/null
+++ b/package/gluon-ebtables-limit-arp/src/lookup3.h
@@ -0,0 +1,6 @@
+#include <stdint.h> /* defines uint32_t etc */
+
+uint32_t hashword(
+const uint32_t *k, /* the key, an array of uint32_t values */
+size_t length, /* the length of the key, in uint32_ts */
+uint32_t initval); /* the previous hash, or an arbitrary value */
diff --git a/package/gluon-ebtables-limit-arp/src/mac.c b/package/gluon-ebtables-limit-arp/src/mac.c
new file mode 100644
index 00000000..863c540e
--- /dev/null
+++ b/package/gluon-ebtables-limit-arp/src/mac.c
@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) 2017 Linus Lüssing <linus.luessing@c0d3.blue>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ * License-Filename: LICENSE
+ */
+
+#include <linux/if_ether.h>
+#include <stdio.h>
+#include <string.h>
+#include "mac.h"
+
+#define ETH_STRLEN (sizeof("aa:bb:cc:dd:ee:ff") - 1)
+
+char mntoa_buf[ETH_STRLEN+1];
+
+int mac_aton(const char *cp, struct mac_addr *mac)
+{
+ struct mac_addr m;
+ int ret;
+
+ if (strlen(cp) != ETH_STRLEN)
+ return 0;
+
+ memset(&m, 0, sizeof(m));
+
+ ret = sscanf(cp, "%hhx:%hhx:%hhx:%hhx:%hhx:%hhx",
+ &m.storage[0], &m.storage[1], &m.storage[2],
+ &m.storage[3], &m.storage[4], &m.storage[5]);
+
+ if (ret != ETH_ALEN)
+ return 0;
+
+ *mac = m;
+ return 1;
+}
+
+char *mac_ntoa(struct mac_addr *mac)
+{
+ unsigned char *m = mac->storage;
+
+ snprintf(mntoa_buf, sizeof(mntoa_buf),
+ "%02x:%02x:%02x:%02x:%02x:%02x",
+ m[0], m[1], m[2], m[3], m[4], m[5]);
+
+ return mntoa_buf;
+}
diff --git a/package/gluon-ebtables-limit-arp/src/mac.h b/package/gluon-ebtables-limit-arp/src/mac.h
new file mode 100644
index 00000000..11567ade
--- /dev/null
+++ b/package/gluon-ebtables-limit-arp/src/mac.h
@@ -0,0 +1,24 @@
+/*
+ * Copyright (c) 2017 Linus Lüssing <linus.luessing@c0d3.blue>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ * License-Filename: LICENSE
+ */
+
+#ifndef _MAC_H_
+#define _MAC_H_
+
+struct mac_addr {
+ /* 8 instead of 6 for multiples of uint32_t for hashword() */
+ unsigned char storage[8];
+};
+
+int mac_aton(const char *cp, struct mac_addr *mac);
+char *mac_ntoa(struct mac_addr *mac);
+
+static inline int mac_is_multicast(struct mac_addr *addr)
+{
+ return addr->storage[0] & 0x01;
+}
+
+#endif /* _MAC_H_ */
--
2.11.0