compat: backport siphash & dst_cache from mainline

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

6 files changed, 1156 insertions, 0 deletions

diff --git a/src/compat/Kbuild.include b/src/compat/Kbuild.include
new file mode 100644
index 0000000..905e268
--- /dev/null
+++ b/src/compat/Kbuild.include
@@ -0,0 +1,11 @@
+ccflags-y += -include $(src)/compat/compat.h
+
+ifeq ($(wildcard $(srctree)/include/linux/siphash.h),)
+ccflags-y += -I$(src)/compat/siphash/include
+wireguard-y += compat/siphash/siphash.o
+endif
+
+ifeq ($(wildcard $(srctree)/include/net/dst_cache.h),)
+ccflags-y += -I$(src)/compat/dst_cache/include
+wireguard-y += compat/dst_cache/dst_cache.o
+endif
diff --git a/src/compat/compat.h b/src/compat/compat.h
new file mode 100644
index 0000000..6a9bfd9
--- /dev/null
+++ b/src/compat/compat.h
@@ -0,0 +1,180 @@
+/* Copyright (C) 2015-2017 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. */
+
+#ifndef COMPAT_H
+#define COMPAT_H
+
+#include <linux/kconfig.h>
+#include <linux/version.h>
+#include <linux/types.h>
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(3, 18, 0)
+#error "WireGuard requires Linux >= 3.18"
+#endif
+
+/* These conditionals can't be enforced by an out of tree module very easily,
+ * so we stick them here in compat instead. */
+#if !IS_ENABLED(CONFIG_NETFILTER_XT_MATCH_HASHLIMIT)
+#error "WireGuard requires CONFIG_NETFILTER_XT_MATCH_HASHLIMIT."
+#endif
+#if IS_ENABLED(CONFIG_IPV6) && !IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
+#error "WireGuard requires CONFIG_IP6_NF_IPTABLES when using CONFIG_IPV6."
+#endif
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 3, 0) && !defined(DEBUG) && defined(net_dbg_ratelimited)
+#undef net_dbg_ratelimited
+#define net_dbg_ratelimited(fmt, ...) do { if (0) no_printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__); } while (0)
+#endif
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 3, 0)
+#define RCU_LOCKDEP_WARN(cond, message) rcu_lockdep_assert(!(cond), message)
+#endif
+
+#if (LINUX_VERSION_CODE > KERNEL_VERSION(3, 19, 0) && LINUX_VERSION_CODE < KERNEL_VERSION(3, 19, 6)) || LINUX_VERSION_CODE < KERNEL_VERSION(3, 18, 12)
+#define dev_recursion_level() 0
+#endif
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 0, 0)
+#include <linux/if.h>
+#include <net/udp_tunnel.h>
+#define udp_tunnel_xmit_skb(a, b, c, d, e, f, g, h, i, j, k, l) do { struct net_device *dev__ = (c)->dev; int ret__; ret__ = udp_tunnel_xmit_skb((b)->sk_socket, a, c, d, e, f, g, h, i, j, k); iptunnel_xmit_stats(ret__, &dev__->stats, dev__->tstats); } while (0)
+#if IS_ENABLED(CONFIG_IPV6)
+#define udp_tunnel6_xmit_skb(a, b, c, d, e, f, g, h, i, j, k, l) udp_tunnel6_xmit_skb((b)->sk_socket, a, c, d, e, f, g, h, j, k);
+#endif
+#elif LINUX_VERSION_CODE < KERNEL_VERSION(4, 1, 0)
+#include <linux/if.h>
+#include <net/udp_tunnel.h>
+static inline void fake_destructor(struct sk_buff *skb)
+{
+}
+#define udp_tunnel_xmit_skb(a, b, c, d, e, f, g, h, i, j, k, l) do { struct net_device *dev__ = (c)->dev; int ret__; (c)->destructor = fake_destructor; (c)->sk = (b); ret__ = udp_tunnel_xmit_skb(a, c, d, e, f, g, h, i, j, k, l); iptunnel_xmit_stats(ret__, &dev__->stats, dev__->tstats); } while (0)
+#if IS_ENABLED(CONFIG_IPV6)
+#define udp_tunnel6_xmit_skb(a, b, c, d, e, f, g, h, i, j, k, l) do { (c)->destructor = fake_destructor; (c)->sk = (b); udp_tunnel6_xmit_skb(a, c, d, e, f, g, h, j, k, l); } while(0)
+#endif
+#else
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 5, 0)
+#include <linux/if.h>
+#include <net/udp_tunnel.h>
+#define udp_tunnel_xmit_skb(a, b, c, d, e, f, g, h, i, j, k, l) do { struct net_device *dev__ = (c)->dev; int ret__ = udp_tunnel_xmit_skb(a, b, c, d, e, f, g, h, i, j, k, l);  iptunnel_xmit_stats(ret__, &dev__->stats, dev__->tstats); } while (0)
+#endif
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 6, 0) && IS_ENABLED(CONFIG_IPV6)
+#include <linux/if.h>
+#include <net/udp_tunnel.h>
+#define udp_tunnel6_xmit_skb(a, b, c, d, e, f, g, h, i, j, k, l) udp_tunnel6_xmit_skb(a, b, c, d, e, f, g, h, j, k, l)
+#endif
+
+#endif
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 3, 0)
+#include <linux/if.h>
+#include <net/udp_tunnel.h>
+struct udp_port_cfg_new {
+	u8 family;
+	union {
+		struct in_addr local_ip;
+#if IS_ENABLED(CONFIG_IPV6)
+		struct in6_addr local_ip6;
+#endif
+	};
+	union {
+		struct in_addr peer_ip;
+#if IS_ENABLED(CONFIG_IPV6)
+		struct in6_addr peer_ip6;
+#endif
+	};
+	__be16 local_udp_port;
+	__be16 peer_udp_port;
+	unsigned int use_udp_checksums:1, use_udp6_tx_checksums:1, use_udp6_rx_checksums:1, ipv6_v6only:1;
+};
+__attribute__((unused)) static inline int udp_sock_create_new(struct net *net, struct udp_port_cfg_new *cfg, struct socket **sockp)
+{
+	struct udp_port_cfg old_cfg = {
+		.family = cfg->family,
+		.local_ip = cfg->local_ip,
+#if IS_ENABLED(CONFIG_IPV6)
+		.local_ip6 = cfg->local_ip6,
+#endif
+		.peer_ip = cfg->peer_ip,
+#if IS_ENABLED(CONFIG_IPV6)
+		.peer_ip6 = cfg->peer_ip6,
+#endif
+		.local_udp_port = cfg->local_udp_port,
+		.peer_udp_port = cfg->peer_udp_port,
+		.use_udp_checksums = cfg->use_udp_checksums,
+		.use_udp6_tx_checksums = cfg->use_udp6_tx_checksums,
+		.use_udp6_rx_checksums = cfg->use_udp6_rx_checksums
+	};
+	if (cfg->family == AF_INET)
+		return udp_sock_create4(net, &old_cfg, sockp);
+
+#if IS_ENABLED(CONFIG_IPV6)
+	if (cfg->family == AF_INET6) {
+		int ret;
+		int old_bindv6only;
+		struct net *nobns;
+
+		if (cfg->ipv6_v6only) {
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 2, 0)
+			nobns = &init_net;
+#else
+			nobns = net;
+#endif
+			/* Since udp_port_cfg only learned of ipv6_v6only in 4.3, we do this horrible
+			 * hack here and set the sysctl variable temporarily to something that will
+			 * set the right option for us in sock_create. It's super racey! */
+			old_bindv6only = nobns->ipv6.sysctl.bindv6only;
+			nobns->ipv6.sysctl.bindv6only = 1;
+		}
+		ret = udp_sock_create6(net, &old_cfg, sockp);
+		if (cfg->ipv6_v6only)
+			nobns->ipv6.sysctl.bindv6only = old_bindv6only;
+		return ret;
+	}
+#endif
+	return -EPFNOSUPPORT;
+}
+#define udp_port_cfg udp_port_cfg_new
+#define udp_sock_create(a, b, c) udp_sock_create_new(a, b, c)
+#endif
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 3, 0)
+#define ipv6_dst_lookup(a, b, c, d) ipv6_dst_lookup(b, c, d)
+#endif
+
+#if (LINUX_VERSION_CODE < KERNEL_VERSION(4, 3, 5) && LINUX_VERSION_CODE >= KERNEL_VERSION(4, 2, 0)) || (LINUX_VERSION_CODE < KERNEL_VERSION(4, 1, 17) && LINUX_VERSION_CODE > KERNEL_VERSION(3, 19, 0)) || LINUX_VERSION_CODE < KERNEL_VERSION(3, 18, 27)
+#define IP6_ECN_set_ce(a, b) IP6_ECN_set_ce(b)
+#endif
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 9, 0)
+#define time_is_before_jiffies64(a) time_after64(get_jiffies_64(), a)
+#define time_is_after_jiffies64(a) time_before64(get_jiffies_64(), a)
+#define time_is_before_eq_jiffies64(a) time_after_eq64(get_jiffies_64(), a)
+#define time_is_after_eq_jiffies64(a) time_before_eq64(get_jiffies_64(), a)
+#endif
+
+/* https://lkml.org/lkml/2015/6/12/415 */
+#include <linux/netdevice.h>
+static inline struct net_device *netdev_pub(void *dev)
+{
+	return (struct net_device *)((char *)dev - ALIGN(sizeof(struct net_device), NETDEV_ALIGN));
+}
+
+/* PaX compatibility */
+#ifdef CONSTIFY_PLUGIN
+#include <linux/cache.h>
+#undef __read_mostly
+#define __read_mostly
+#endif
+
+#if defined(CONFIG_DYNAMIC_DEBUG) || defined(DEBUG)
+#define net_dbg_skb_ratelimited(fmt, skb, ...) do { \
+	struct endpoint __endpoint; \
+	socket_endpoint_from_skb(&__endpoint, skb); \
+	net_dbg_ratelimited(fmt, &__endpoint.addr, ##__VA_ARGS__); \
+} while(0)
+#else
+#define net_dbg_skb_ratelimited(fmt, skb, ...)
+#endif
+
+#endif
diff --git a/src/compat/dst_cache/dst_cache.c b/src/compat/dst_cache/dst_cache.c
new file mode 100644
index 0000000..145f112
--- /dev/null
+++ b/src/compat/dst_cache/dst_cache.c
@@ -0,0 +1,177 @@
+/*
+ * net/core/dst_cache.c - dst entry cache
+ *
+ * Copyright (c) 2016 Paolo Abeni <pabeni@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/percpu.h>
+#include <net/dst_cache.h>
+#include <net/route.h>
+#if IS_ENABLED(CONFIG_IPV6)
+#include <net/ip6_fib.h>
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 2, 0)
+static inline u32 rt6_get_cookie(const struct rt6_info *rt)
+{
+	if ((unlikely(rt->dst.flags & DST_NOCACHE) && rt->dst.from))
+		rt = (struct rt6_info *)(rt->dst.from);
+
+	return rt->rt6i_node ? rt->rt6i_node->fn_sernum : 0;
+}
+#endif
+#endif
+#include <uapi/linux/in.h>
+
+struct dst_cache_pcpu {
+	unsigned long refresh_ts;
+	struct dst_entry *dst;
+	u32 cookie;
+	union {
+		struct in_addr in_saddr;
+		struct in6_addr in6_saddr;
+	};
+};
+
+static void dst_cache_per_cpu_dst_set(struct dst_cache_pcpu *dst_cache,
+				      struct dst_entry *dst, u32 cookie)
+{
+	dst_release(dst_cache->dst);
+	if (dst)
+		dst_hold(dst);
+
+	dst_cache->cookie = cookie;
+	dst_cache->dst = dst;
+}
+
+static struct dst_entry *dst_cache_per_cpu_get(struct dst_cache *dst_cache,
+					       struct dst_cache_pcpu *idst)
+{
+	struct dst_entry *dst;
+
+	dst = idst->dst;
+	if (!dst)
+		goto fail;
+
+	/* the cache already hold a dst reference; it can't go away */
+	dst_hold(dst);
+
+	if (unlikely(!time_after(idst->refresh_ts, dst_cache->reset_ts) ||
+		     (dst->obsolete && !dst->ops->check(dst, idst->cookie)))) {
+		dst_cache_per_cpu_dst_set(idst, NULL, 0);
+		dst_release(dst);
+		goto fail;
+	}
+	return dst;
+
+fail:
+	idst->refresh_ts = jiffies;
+	return NULL;
+}
+
+struct dst_entry *dst_cache_get(struct dst_cache *dst_cache)
+{
+	if (!dst_cache->cache)
+		return NULL;
+
+	return dst_cache_per_cpu_get(dst_cache, this_cpu_ptr(dst_cache->cache));
+}
+EXPORT_SYMBOL_GPL(dst_cache_get);
+
+struct rtable *dst_cache_get_ip4(struct dst_cache *dst_cache, __be32 *saddr)
+{
+	struct dst_cache_pcpu *idst;
+	struct dst_entry *dst;
+
+	if (!dst_cache->cache)
+		return NULL;
+
+	idst = this_cpu_ptr(dst_cache->cache);
+	dst = dst_cache_per_cpu_get(dst_cache, idst);
+	if (!dst)
+		return NULL;
+
+	*saddr = idst->in_saddr.s_addr;
+	return container_of(dst, struct rtable, dst);
+}
+EXPORT_SYMBOL_GPL(dst_cache_get_ip4);
+
+void dst_cache_set_ip4(struct dst_cache *dst_cache, struct dst_entry *dst,
+		       __be32 saddr)
+{
+	struct dst_cache_pcpu *idst;
+
+	if (!dst_cache->cache)
+		return;
+
+	idst = this_cpu_ptr(dst_cache->cache);
+	dst_cache_per_cpu_dst_set(idst, dst, 0);
+	idst->in_saddr.s_addr = saddr;
+}
+EXPORT_SYMBOL_GPL(dst_cache_set_ip4);
+
+#if IS_ENABLED(CONFIG_IPV6)
+void dst_cache_set_ip6(struct dst_cache *dst_cache, struct dst_entry *dst,
+		       const struct in6_addr *addr)
+{
+	struct dst_cache_pcpu *idst;
+
+	if (!dst_cache->cache)
+		return;
+
+	idst = this_cpu_ptr(dst_cache->cache);
+	dst_cache_per_cpu_dst_set(this_cpu_ptr(dst_cache->cache), dst,
+				  rt6_get_cookie((struct rt6_info *)dst));
+	idst->in6_saddr = *addr;
+}
+EXPORT_SYMBOL_GPL(dst_cache_set_ip6);
+
+struct dst_entry *dst_cache_get_ip6(struct dst_cache *dst_cache,
+				    struct in6_addr *saddr)
+{
+	struct dst_cache_pcpu *idst;
+	struct dst_entry *dst;
+
+	if (!dst_cache->cache)
+		return NULL;
+
+	idst = this_cpu_ptr(dst_cache->cache);
+	dst = dst_cache_per_cpu_get(dst_cache, idst);
+	if (!dst)
+		return NULL;
+
+	*saddr = idst->in6_saddr;
+	return dst;
+}
+EXPORT_SYMBOL_GPL(dst_cache_get_ip6);
+#endif
+
+int dst_cache_init(struct dst_cache *dst_cache, gfp_t gfp)
+{
+	dst_cache->cache = alloc_percpu_gfp(struct dst_cache_pcpu,
+					    gfp | __GFP_ZERO);
+	if (!dst_cache->cache)
+		return -ENOMEM;
+
+	dst_cache_reset(dst_cache);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(dst_cache_init);
+
+void dst_cache_destroy(struct dst_cache *dst_cache)
+{
+	int i;
+
+	if (!dst_cache->cache)
+		return;
+
+	for_each_possible_cpu(i)
+		dst_release(per_cpu_ptr(dst_cache->cache, i)->dst);
+
+	free_percpu(dst_cache->cache);
+}
+EXPORT_SYMBOL_GPL(dst_cache_destroy);
diff --git a/src/compat/dst_cache/include/net/dst_cache.h b/src/compat/dst_cache/include/net/dst_cache.h
new file mode 100644
index 0000000..151acca
--- /dev/null
+++ b/src/compat/dst_cache/include/net/dst_cache.h
@@ -0,0 +1,97 @@
+#ifndef _NET_DST_CACHE_H
+#define _NET_DST_CACHE_H
+
+#include <linux/jiffies.h>
+#include <net/dst.h>
+#if IS_ENABLED(CONFIG_IPV6)
+#include <net/ip6_fib.h>
+#endif
+
+struct dst_cache {
+	struct dst_cache_pcpu __percpu *cache;
+	unsigned long reset_ts;
+};
+
+/**
+ *	dst_cache_get - perform cache lookup
+ *	@dst_cache: the cache
+ *
+ *	The caller should use dst_cache_get_ip4() if it need to retrieve the
+ *	source address to be used when xmitting to the cached dst.
+ *	local BH must be disabled.
+ */
+struct dst_entry *dst_cache_get(struct dst_cache *dst_cache);
+
+/**
+ *	dst_cache_get_ip4 - perform cache lookup and fetch ipv4 source address
+ *	@dst_cache: the cache
+ *	@saddr: return value for the retrieved source address
+ *
+ *	local BH must be disabled.
+ */
+struct rtable *dst_cache_get_ip4(struct dst_cache *dst_cache, __be32 *saddr);
+
+/**
+ *	dst_cache_set_ip4 - store the ipv4 dst into the cache
+ *	@dst_cache: the cache
+ *	@dst: the entry to be cached
+ *	@saddr: the source address to be stored inside the cache
+ *
+ *	local BH must be disabled.
+ */
+void dst_cache_set_ip4(struct dst_cache *dst_cache, struct dst_entry *dst,
+		       __be32 saddr);
+
+#if IS_ENABLED(CONFIG_IPV6)
+
+/**
+ *	dst_cache_set_ip6 - store the ipv6 dst into the cache
+ *	@dst_cache: the cache
+ *	@dst: the entry to be cached
+ *	@saddr: the source address to be stored inside the cache
+ *
+ *	local BH must be disabled.
+ */
+void dst_cache_set_ip6(struct dst_cache *dst_cache, struct dst_entry *dst,
+		       const struct in6_addr *addr);
+
+/**
+ *	dst_cache_get_ip6 - perform cache lookup and fetch ipv6 source address
+ *	@dst_cache: the cache
+ *	@saddr: return value for the retrieved source address
+ *
+ *	local BH must be disabled.
+ */
+struct dst_entry *dst_cache_get_ip6(struct dst_cache *dst_cache,
+				    struct in6_addr *saddr);
+#endif
+
+/**
+ *	dst_cache_reset - invalidate the cache contents
+ *	@dst_cache: the cache
+ *
+ *	This do not free the cached dst to avoid races and contentions.
+ *	the dst will be freed on later cache lookup.
+ */
+static inline void dst_cache_reset(struct dst_cache *dst_cache)
+{
+	dst_cache->reset_ts = jiffies;
+}
+
+/**
+ *	dst_cache_init - initialize the cache, allocating the required storage
+ *	@dst_cache: the cache
+ *	@gfp: allocation flags
+ */
+int dst_cache_init(struct dst_cache *dst_cache, gfp_t gfp);
+
+/**
+ *	dst_cache_destroy - empty the cache and free the allocated storage
+ *	@dst_cache: the cache
+ *
+ *	No synchronization is enforced: it must be called only when the cache
+ *	is unsed.
+ */
+void dst_cache_destroy(struct dst_cache *dst_cache);
+
+#endif
diff --git a/src/compat/siphash/include/linux/siphash.h b/src/compat/siphash/include/linux/siphash.h
new file mode 100644
index 0000000..fa7a6b9
--- /dev/null
+++ b/src/compat/siphash/include/linux/siphash.h
@@ -0,0 +1,140 @@
+/* Copyright (C) 2016 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ *
+ * This file is provided under a dual BSD/GPLv2 license.
+ *
+ * SipHash: a fast short-input PRF
+ * https://131002.net/siphash/
+ *
+ * This implementation is specifically for SipHash2-4 for a secure PRF
+ * and HalfSipHash1-3/SipHash1-3 for an insecure PRF only suitable for
+ * hashtables.
+ */
+
+#ifndef _LINUX_SIPHASH_H
+#define _LINUX_SIPHASH_H
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+
+#define SIPHASH_ALIGNMENT __alignof__(u64)
+typedef struct {
+	u64 key[2];
+} siphash_key_t;
+
+u64 __siphash_aligned(const void *data, size_t len, const siphash_key_t *key);
+#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
+u64 __siphash_unaligned(const void *data, size_t len, const siphash_key_t *key);
+#endif
+
+u64 siphash_1u64(const u64 a, const siphash_key_t *key);
+u64 siphash_2u64(const u64 a, const u64 b, const siphash_key_t *key);
+u64 siphash_3u64(const u64 a, const u64 b, const u64 c,
+		 const siphash_key_t *key);
+u64 siphash_4u64(const u64 a, const u64 b, const u64 c, const u64 d,
+		 const siphash_key_t *key);
+u64 siphash_1u32(const u32 a, const siphash_key_t *key);
+u64 siphash_3u32(const u32 a, const u32 b, const u32 c,
+		 const siphash_key_t *key);
+
+static inline u64 siphash_2u32(const u32 a, const u32 b,
+			       const siphash_key_t *key)
+{
+	return siphash_1u64((u64)b << 32 | a, key);
+}
+static inline u64 siphash_4u32(const u32 a, const u32 b, const u32 c,
+			       const u32 d, const siphash_key_t *key)
+{
+	return siphash_2u64((u64)b << 32 | a, (u64)d << 32 | c, key);
+}
+
+
+static inline u64 ___siphash_aligned(const __le64 *data, size_t len,
+				     const siphash_key_t *key)
+{
+	if (__builtin_constant_p(len) && len == 4)
+		return siphash_1u32(le32_to_cpup((const __le32 *)data), key);
+	if (__builtin_constant_p(len) && len == 8)
+		return siphash_1u64(le64_to_cpu(data[0]), key);
+	if (__builtin_constant_p(len) && len == 16)
+		return siphash_2u64(le64_to_cpu(data[0]), le64_to_cpu(data[1]),
+				    key);
+	if (__builtin_constant_p(len) && len == 24)
+		return siphash_3u64(le64_to_cpu(data[0]), le64_to_cpu(data[1]),
+				    le64_to_cpu(data[2]), key);
+	if (__builtin_constant_p(len) && len == 32)
+		return siphash_4u64(le64_to_cpu(data[0]), le64_to_cpu(data[1]),
+				    le64_to_cpu(data[2]), le64_to_cpu(data[3]),
+				    key);
+	return __siphash_aligned(data, len, key);
+}
+
+/**
+ * siphash - compute 64-bit siphash PRF value
+ * @data: buffer to hash
+ * @size: size of @data
+ * @key: the siphash key
+ */
+static inline u64 siphash(const void *data, size_t len,
+			  const siphash_key_t *key)
+{
+#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
+	if (!IS_ALIGNED((unsigned long)data, SIPHASH_ALIGNMENT))
+		return __siphash_unaligned(data, len, key);
+#endif
+	return ___siphash_aligned(data, len, key);
+}
+
+#define HSIPHASH_ALIGNMENT __alignof__(unsigned long)
+typedef struct {
+	unsigned long key[2];
+} hsiphash_key_t;
+
+u32 __hsiphash_aligned(const void *data, size_t len,
+		       const hsiphash_key_t *key);
+#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
+u32 __hsiphash_unaligned(const void *data, size_t len,
+			 const hsiphash_key_t *key);
+#endif
+
+u32 hsiphash_1u32(const u32 a, const hsiphash_key_t *key);
+u32 hsiphash_2u32(const u32 a, const u32 b, const hsiphash_key_t *key);
+u32 hsiphash_3u32(const u32 a, const u32 b, const u32 c,
+		  const hsiphash_key_t *key);
+u32 hsiphash_4u32(const u32 a, const u32 b, const u32 c, const u32 d,
+		  const hsiphash_key_t *key);
+
+static inline u32 ___hsiphash_aligned(const __le32 *data, size_t len,
+				      const hsiphash_key_t *key)
+{
+	if (__builtin_constant_p(len) && len == 4)
+		return hsiphash_1u32(le32_to_cpu(data[0]), key);
+	if (__builtin_constant_p(len) && len == 8)
+		return hsiphash_2u32(le32_to_cpu(data[0]), le32_to_cpu(data[1]),
+				     key);
+	if (__builtin_constant_p(len) && len == 12)
+		return hsiphash_3u32(le32_to_cpu(data[0]), le32_to_cpu(data[1]),
+				     le32_to_cpu(data[2]), key);
+	if (__builtin_constant_p(len) && len == 16)
+		return hsiphash_4u32(le32_to_cpu(data[0]), le32_to_cpu(data[1]),
+				     le32_to_cpu(data[2]), le32_to_cpu(data[3]),
+				     key);
+	return __hsiphash_aligned(data, len, key);
+}
+
+/**
+ * hsiphash - compute 32-bit hsiphash PRF value
+ * @data: buffer to hash
+ * @size: size of @data
+ * @key: the hsiphash key
+ */
+static inline u32 hsiphash(const void *data, size_t len,
+			   const hsiphash_key_t *key)
+{
+#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
+	if (!IS_ALIGNED((unsigned long)data, HSIPHASH_ALIGNMENT))
+		return __hsiphash_unaligned(data, len, key);
+#endif
+	return ___hsiphash_aligned(data, len, key);
+}
+
+#endif /* _LINUX_SIPHASH_H */
diff --git a/src/compat/siphash/siphash.c b/src/compat/siphash/siphash.c
new file mode 100644
index 0000000..3ae58b4
--- /dev/null
+++ b/src/compat/siphash/siphash.c
@@ -0,0 +1,551 @@
+/* Copyright (C) 2016 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ *
+ * This file is provided under a dual BSD/GPLv2 license.
+ *
+ * SipHash: a fast short-input PRF
+ * https://131002.net/siphash/
+ *
+ * This implementation is specifically for SipHash2-4 for a secure PRF
+ * and HalfSipHash1-3/SipHash1-3 for an insecure PRF only suitable for
+ * hashtables.
+ */
+
+#include <linux/siphash.h>
+#include <asm/unaligned.h>
+
+#if defined(CONFIG_DCACHE_WORD_ACCESS) && BITS_PER_LONG == 64
+#include <linux/dcache.h>
+#include <asm/word-at-a-time.h>
+#endif
+
+#define SIPROUND \
+	do { \
+	v0 += v1; v1 = rol64(v1, 13); v1 ^= v0; v0 = rol64(v0, 32); \
+	v2 += v3; v3 = rol64(v3, 16); v3 ^= v2; \
+	v0 += v3; v3 = rol64(v3, 21); v3 ^= v0; \
+	v2 += v1; v1 = rol64(v1, 17); v1 ^= v2; v2 = rol64(v2, 32); \
+	} while (0)
+
+#define PREAMBLE(len) \
+	u64 v0 = 0x736f6d6570736575ULL; \
+	u64 v1 = 0x646f72616e646f6dULL; \
+	u64 v2 = 0x6c7967656e657261ULL; \
+	u64 v3 = 0x7465646279746573ULL; \
+	u64 b = ((u64)(len)) << 56; \
+	v3 ^= key->key[1]; \
+	v2 ^= key->key[0]; \
+	v1 ^= key->key[1]; \
+	v0 ^= key->key[0];
+
+#define POSTAMBLE \
+	v3 ^= b; \
+	SIPROUND; \
+	SIPROUND; \
+	v0 ^= b; \
+	v2 ^= 0xff; \
+	SIPROUND; \
+	SIPROUND; \
+	SIPROUND; \
+	SIPROUND; \
+	return (v0 ^ v1) ^ (v2 ^ v3);
+
+u64 __siphash_aligned(const void *data, size_t len, const siphash_key_t *key)
+{
+	const u8 *end = data + len - (len % sizeof(u64));
+	const u8 left = len & (sizeof(u64) - 1);
+	u64 m;
+	PREAMBLE(len)
+	for (; data != end; data += sizeof(u64)) {
+		m = le64_to_cpup(data);
+		v3 ^= m;
+		SIPROUND;
+		SIPROUND;
+		v0 ^= m;
+	}
+#if defined(CONFIG_DCACHE_WORD_ACCESS) && BITS_PER_LONG == 64
+	if (left)
+		b |= le64_to_cpu((__force __le64)(load_unaligned_zeropad(data) &
+						  bytemask_from_count(left)));
+#else
+	switch (left) {
+	case 7: b |= ((u64)end[6]) << 48;
+	case 6: b |= ((u64)end[5]) << 40;
+	case 5: b |= ((u64)end[4]) << 32;
+	case 4: b |= le32_to_cpup(data); break;
+	case 3: b |= ((u64)end[2]) << 16;
+	case 2: b |= le16_to_cpup(data); break;
+	case 1: b |= end[0];
+	}
+#endif
+	POSTAMBLE
+}
+EXPORT_SYMBOL(__siphash_aligned);
+
+#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
+u64 __siphash_unaligned(const void *data, size_t len, const siphash_key_t *key)
+{
+	const u8 *end = data + len - (len % sizeof(u64));
+	const u8 left = len & (sizeof(u64) - 1);
+	u64 m;
+	PREAMBLE(len)
+	for (; data != end; data += sizeof(u64)) {
+		m = get_unaligned_le64(data);
+		v3 ^= m;
+		SIPROUND;
+		SIPROUND;
+		v0 ^= m;
+	}
+#if defined(CONFIG_DCACHE_WORD_ACCESS) && BITS_PER_LONG == 64
+	if (left)
+		b |= le64_to_cpu((__force __le64)(load_unaligned_zeropad(data) &
+						  bytemask_from_count(left)));
+#else
+	switch (left) {
+	case 7: b |= ((u64)end[6]) << 48;
+	case 6: b |= ((u64)end[5]) << 40;
+	case 5: b |= ((u64)end[4]) << 32;
+	case 4: b |= get_unaligned_le32(end); break;
+	case 3: b |= ((u64)end[2]) << 16;
+	case 2: b |= get_unaligned_le16(end); break;
+	case 1: b |= end[0];
+	}
+#endif
+	POSTAMBLE
+}
+EXPORT_SYMBOL(__siphash_unaligned);
+#endif
+
+/**
+ * siphash_1u64 - compute 64-bit siphash PRF value of a u64
+ * @first: first u64
+ * @key: the siphash key
+ */
+u64 siphash_1u64(const u64 first, const siphash_key_t *key)
+{
+	PREAMBLE(8)
+	v3 ^= first;
+	SIPROUND;
+	SIPROUND;
+	v0 ^= first;
+	POSTAMBLE
+}
+EXPORT_SYMBOL(siphash_1u64);
+
+/**
+ * siphash_2u64 - compute 64-bit siphash PRF value of 2 u64
+ * @first: first u64
+ * @second: second u64
+ * @key: the siphash key
+ */
+u64 siphash_2u64(const u64 first, const u64 second, const siphash_key_t *key)
+{
+	PREAMBLE(16)
+	v3 ^= first;
+	SIPROUND;
+	SIPROUND;
+	v0 ^= first;
+	v3 ^= second;
+	SIPROUND;
+	SIPROUND;
+	v0 ^= second;
+	POSTAMBLE
+}
+EXPORT_SYMBOL(siphash_2u64);
+
+/**
+ * siphash_3u64 - compute 64-bit siphash PRF value of 3 u64
+ * @first: first u64
+ * @second: second u64
+ * @third: third u64
+ * @key: the siphash key
+ */
+u64 siphash_3u64(const u64 first, const u64 second, const u64 third,
+		 const siphash_key_t *key)
+{
+	PREAMBLE(24)
+	v3 ^= first;
+	SIPROUND;
+	SIPROUND;
+	v0 ^= first;
+	v3 ^= second;
+	SIPROUND;
+	SIPROUND;
+	v0 ^= second;
+	v3 ^= third;
+	SIPROUND;
+	SIPROUND;
+	v0 ^= third;
+	POSTAMBLE
+}
+EXPORT_SYMBOL(siphash_3u64);
+
+/**
+ * siphash_4u64 - compute 64-bit siphash PRF value of 4 u64
+ * @first: first u64
+ * @second: second u64
+ * @third: third u64
+ * @forth: forth u64
+ * @key: the siphash key
+ */
+u64 siphash_4u64(const u64 first, const u64 second, const u64 third,
+		 const u64 forth, const siphash_key_t *key)
+{
+	PREAMBLE(32)
+	v3 ^= first;
+	SIPROUND;
+	SIPROUND;
+	v0 ^= first;
+	v3 ^= second;
+	SIPROUND;
+	SIPROUND;
+	v0 ^= second;
+	v3 ^= third;
+	SIPROUND;
+	SIPROUND;
+	v0 ^= third;
+	v3 ^= forth;
+	SIPROUND;
+	SIPROUND;
+	v0 ^= forth;
+	POSTAMBLE
+}
+EXPORT_SYMBOL(siphash_4u64);
+
+u64 siphash_1u32(const u32 first, const siphash_key_t *key)
+{
+	PREAMBLE(4)
+	b |= first;
+	POSTAMBLE
+}
+EXPORT_SYMBOL(siphash_1u32);
+
+u64 siphash_3u32(const u32 first, const u32 second, const u32 third,
+		 const siphash_key_t *key)
+{
+	u64 combined = (u64)second << 32 | first;
+	PREAMBLE(12)
+	v3 ^= combined;
+	SIPROUND;
+	SIPROUND;
+	v0 ^= combined;
+	b |= third;
+	POSTAMBLE
+}
+EXPORT_SYMBOL(siphash_3u32);
+
+#if BITS_PER_LONG == 64
+/* Note that on 64-bit, we make HalfSipHash1-3 actually be SipHash1-3, for
+ * performance reasons. On 32-bit, below, we actually implement HalfSipHash1-3.
+ */
+
+#define HSIPROUND SIPROUND
+#define HPREAMBLE(len) PREAMBLE(len)
+#define HPOSTAMBLE \
+	v3 ^= b; \
+	HSIPROUND; \
+	v0 ^= b; \
+	v2 ^= 0xff; \
+	HSIPROUND; \
+	HSIPROUND; \
+	HSIPROUND; \
+	return (v0 ^ v1) ^ (v2 ^ v3);
+
+u32 __hsiphash_aligned(const void *data, size_t len, const hsiphash_key_t *key)
+{
+	const u8 *end = data + len - (len % sizeof(u64));
+	const u8 left = len & (sizeof(u64) - 1);
+	u64 m;
+	HPREAMBLE(len)
+	for (; data != end; data += sizeof(u64)) {
+		m = le64_to_cpup(data);
+		v3 ^= m;
+		HSIPROUND;
+		v0 ^= m;
+	}
+#if defined(CONFIG_DCACHE_WORD_ACCESS) && BITS_PER_LONG == 64
+	if (left)
+		b |= le64_to_cpu((__force __le64)(load_unaligned_zeropad(data) &
+						  bytemask_from_count(left)));
+#else
+	switch (left) {
+	case 7: b |= ((u64)end[6]) << 48;
+	case 6: b |= ((u64)end[5]) << 40;
+	case 5: b |= ((u64)end[4]) << 32;
+	case 4: b |= le32_to_cpup(data); break;
+	case 3: b |= ((u64)end[2]) << 16;
+	case 2: b |= le16_to_cpup(data); break;
+	case 1: b |= end[0];
+	}
+#endif
+	HPOSTAMBLE
+}
+EXPORT_SYMBOL(__hsiphash_aligned);
+
+#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
+u32 __hsiphash_unaligned(const void *data, size_t len,
+			 const hsiphash_key_t *key)
+{
+	const u8 *end = data + len - (len % sizeof(u64));
+	const u8 left = len & (sizeof(u64) - 1);
+	u64 m;
+	HPREAMBLE(len)
+	for (; data != end; data += sizeof(u64)) {
+		m = get_unaligned_le64(data);
+		v3 ^= m;
+		HSIPROUND;
+		v0 ^= m;
+	}
+#if defined(CONFIG_DCACHE_WORD_ACCESS) && BITS_PER_LONG == 64
+	if (left)
+		b |= le64_to_cpu((__force __le64)(load_unaligned_zeropad(data) &
+						  bytemask_from_count(left)));
+#else
+	switch (left) {
+	case 7: b |= ((u64)end[6]) << 48;
+	case 6: b |= ((u64)end[5]) << 40;
+	case 5: b |= ((u64)end[4]) << 32;
+	case 4: b |= get_unaligned_le32(end); break;
+	case 3: b |= ((u64)end[2]) << 16;
+	case 2: b |= get_unaligned_le16(end); break;
+	case 1: b |= end[0];
+	}
+#endif
+	HPOSTAMBLE
+}
+EXPORT_SYMBOL(__hsiphash_unaligned);
+#endif
+
+/**
+ * hsiphash_1u32 - compute 64-bit hsiphash PRF value of a u32
+ * @first: first u32
+ * @key: the hsiphash key
+ */
+u32 hsiphash_1u32(const u32 first, const hsiphash_key_t *key)
+{
+	HPREAMBLE(4)
+	b |= first;
+	HPOSTAMBLE
+}
+EXPORT_SYMBOL(hsiphash_1u32);
+
+/**
+ * hsiphash_2u32 - compute 32-bit hsiphash PRF value of 2 u32
+ * @first: first u32
+ * @second: second u32
+ * @key: the hsiphash key
+ */
+u32 hsiphash_2u32(const u32 first, const u32 second, const hsiphash_key_t *key)
+{
+	u64 combined = (u64)second << 32 | first;
+	HPREAMBLE(8)
+	v3 ^= combined;
+	HSIPROUND;
+	v0 ^= combined;
+	HPOSTAMBLE
+}
+EXPORT_SYMBOL(hsiphash_2u32);
+
+/**
+ * hsiphash_3u32 - compute 32-bit hsiphash PRF value of 3 u32
+ * @first: first u32
+ * @second: second u32
+ * @third: third u32
+ * @key: the hsiphash key
+ */
+u32 hsiphash_3u32(const u32 first, const u32 second, const u32 third,
+		  const hsiphash_key_t *key)
+{
+	u64 combined = (u64)second << 32 | first;
+	HPREAMBLE(12)
+	v3 ^= combined;
+	HSIPROUND;
+	v0 ^= combined;
+	b |= third;
+	HPOSTAMBLE
+}
+EXPORT_SYMBOL(hsiphash_3u32);
+
+/**
+ * hsiphash_4u32 - compute 32-bit hsiphash PRF value of 4 u32
+ * @first: first u32
+ * @second: second u32
+ * @third: third u32
+ * @forth: forth u32
+ * @key: the hsiphash key
+ */
+u32 hsiphash_4u32(const u32 first, const u32 second, const u32 third,
+		  const u32 forth, const hsiphash_key_t *key)
+{
+	u64 combined = (u64)second << 32 | first;
+	HPREAMBLE(16)
+	v3 ^= combined;
+	HSIPROUND;
+	v0 ^= combined;
+	combined = (u64)forth << 32 | third;
+	v3 ^= combined;
+	HSIPROUND;
+	v0 ^= combined;
+	HPOSTAMBLE
+}
+EXPORT_SYMBOL(hsiphash_4u32);
+#else
+#define HSIPROUND \
+	do { \
+	v0 += v1; v1 = rol32(v1, 5); v1 ^= v0; v0 = rol32(v0, 16); \
+	v2 += v3; v3 = rol32(v3, 8); v3 ^= v2; \
+	v0 += v3; v3 = rol32(v3, 7); v3 ^= v0; \
+	v2 += v1; v1 = rol32(v1, 13); v1 ^= v2; v2 = rol32(v2, 16); \
+	} while (0)
+
+#define HPREAMBLE(len) \
+	u32 v0 = 0; \
+	u32 v1 = 0; \
+	u32 v2 = 0x6c796765U; \
+	u32 v3 = 0x74656462U; \
+	u32 b = ((u32)(len)) << 24; \
+	v3 ^= key->key[1]; \
+	v2 ^= key->key[0]; \
+	v1 ^= key->key[1]; \
+	v0 ^= key->key[0];
+
+#define HPOSTAMBLE \
+	v3 ^= b; \
+	HSIPROUND; \
+	v0 ^= b; \
+	v2 ^= 0xff; \
+	HSIPROUND; \
+	HSIPROUND; \
+	HSIPROUND; \
+	return v1 ^ v3;
+
+u32 __hsiphash_aligned(const void *data, size_t len, const hsiphash_key_t *key)
+{
+	const u8 *end = data + len - (len % sizeof(u32));
+	const u8 left = len & (sizeof(u32) - 1);
+	u32 m;
+	HPREAMBLE(len)
+	for (; data != end; data += sizeof(u32)) {
+		m = le32_to_cpup(data);
+		v3 ^= m;
+		HSIPROUND;
+		v0 ^= m;
+	}
+	switch (left) {
+	case 3: b |= ((u32)end[2]) << 16;
+	case 2: b |= le16_to_cpup(data); break;
+	case 1: b |= end[0];
+	}
+	HPOSTAMBLE
+}
+EXPORT_SYMBOL(__hsiphash_aligned);
+
+#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
+u32 __hsiphash_unaligned(const void *data, size_t len,
+			 const hsiphash_key_t *key)
+{
+	const u8 *end = data + len - (len % sizeof(u32));
+	const u8 left = len & (sizeof(u32) - 1);
+	u32 m;
+	HPREAMBLE(len)
+	for (; data != end; data += sizeof(u32)) {
+		m = get_unaligned_le32(data);
+		v3 ^= m;
+		HSIPROUND;
+		v0 ^= m;
+	}
+	switch (left) {
+	case 3: b |= ((u32)end[2]) << 16;
+	case 2: b |= get_unaligned_le16(end); break;
+	case 1: b |= end[0];
+	}
+	HPOSTAMBLE
+}
+EXPORT_SYMBOL(__hsiphash_unaligned);
+#endif
+
+/**
+ * hsiphash_1u32 - compute 32-bit hsiphash PRF value of a u32
+ * @first: first u32
+ * @key: the hsiphash key
+ */
+u32 hsiphash_1u32(const u32 first, const hsiphash_key_t *key)
+{
+	HPREAMBLE(4)
+	v3 ^= first;
+	HSIPROUND;
+	v0 ^= first;
+	HPOSTAMBLE
+}
+EXPORT_SYMBOL(hsiphash_1u32);
+
+/**
+ * hsiphash_2u32 - compute 32-bit hsiphash PRF value of 2 u32
+ * @first: first u32
+ * @second: second u32
+ * @key: the hsiphash key
+ */
+u32 hsiphash_2u32(const u32 first, const u32 second, const hsiphash_key_t *key)
+{
+	HPREAMBLE(8)
+	v3 ^= first;
+	HSIPROUND;
+	v0 ^= first;
+	v3 ^= second;
+	HSIPROUND;
+	v0 ^= second;
+	HPOSTAMBLE
+}
+EXPORT_SYMBOL(hsiphash_2u32);
+
+/**
+ * hsiphash_3u32 - compute 32-bit hsiphash PRF value of 3 u32
+ * @first: first u32
+ * @second: second u32
+ * @third: third u32
+ * @key: the hsiphash key
+ */
+u32 hsiphash_3u32(const u32 first, const u32 second, const u32 third,
+		  const hsiphash_key_t *key)
+{
+	HPREAMBLE(12)
+	v3 ^= first;
+	HSIPROUND;
+	v0 ^= first;
+	v3 ^= second;
+	HSIPROUND;
+	v0 ^= second;
+	v3 ^= third;
+	HSIPROUND;
+	v0 ^= third;
+	HPOSTAMBLE
+}
+EXPORT_SYMBOL(hsiphash_3u32);
+
+/**
+ * hsiphash_4u32 - compute 32-bit hsiphash PRF value of 4 u32
+ * @first: first u32
+ * @second: second u32
+ * @third: third u32
+ * @forth: forth u32
+ * @key: the hsiphash key
+ */
+u32 hsiphash_4u32(const u32 first, const u32 second, const u32 third,
+		  const u32 forth, const hsiphash_key_t *key)
+{
+	HPREAMBLE(16)
+	v3 ^= first;
+	HSIPROUND;
+	v0 ^= first;
+	v3 ^= second;
+	HSIPROUND;
+	v0 ^= second;
+	v3 ^= third;
+	HSIPROUND;
+	v0 ^= third;
+	v3 ^= forth;
+	HSIPROUND;
+	v0 ^= forth;
+	HPOSTAMBLE
+}
+EXPORT_SYMBOL(hsiphash_4u32);
+#endif