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-rw-r--r--net/core/dst_cache.c168
1 files changed, 168 insertions, 0 deletions
diff --git a/net/core/dst_cache.c b/net/core/dst_cache.c
new file mode 100644
index 000000000000..554d36449231
--- /dev/null
+++ b/net/core/dst_cache.c
@@ -0,0 +1,168 @@
+/*
+ * 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>
+#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);