/* * 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);