#include <linux/seq_file.h>
#include <linux/nsproxy.h>
#include <linux/slab.h>
+#include <linux/jhash.h>
#include <net/net_namespace.h>
#include <net/snmp.h>
#include <net/ipv6.h>
struct in6_addr *dst, struct in6_addr *src,
int iif, int type, u32 portid, u32 seq,
unsigned int flags);
+static struct rt6_info *rt6_find_cached_rt(struct rt6_info *rt,
+ struct in6_addr *daddr,
+ struct in6_addr *saddr);
#ifdef CONFIG_IPV6_ROUTE_INFO
static struct rt6_info *rt6_add_route_info(struct net *net,
static void ip6_dst_destroy(struct dst_entry *dst)
{
struct rt6_info *rt = (struct rt6_info *)dst;
+ struct rt6_exception_bucket *bucket;
struct dst_entry *from = dst->from;
struct inet6_dev *idev;
rt->rt6i_idev = NULL;
in6_dev_put(idev);
}
+ bucket = rcu_dereference_protected(rt->rt6i_exception_bucket, 1);
+ if (bucket) {
+ rt->rt6i_exception_bucket = NULL;
+ kfree(bucket);
+ }
dst->from = NULL;
dst_release(from);
return pcpu_rt;
}
+/* exception hash table implementation
+ */
+static DEFINE_SPINLOCK(rt6_exception_lock);
+
+/* Remove rt6_ex from hash table and free the memory
+ * Caller must hold rt6_exception_lock
+ */
+static void rt6_remove_exception(struct rt6_exception_bucket *bucket,
+ struct rt6_exception *rt6_ex)
+{
+ if (!bucket || !rt6_ex)
+ return;
+ rt6_ex->rt6i->rt6i_node = NULL;
+ hlist_del_rcu(&rt6_ex->hlist);
+ rt6_release(rt6_ex->rt6i);
+ kfree_rcu(rt6_ex, rcu);
+ WARN_ON_ONCE(!bucket->depth);
+ bucket->depth--;
+}
+
+/* Remove oldest rt6_ex in bucket and free the memory
+ * Caller must hold rt6_exception_lock
+ */
+static void rt6_exception_remove_oldest(struct rt6_exception_bucket *bucket)
+{
+ struct rt6_exception *rt6_ex, *oldest = NULL;
+
+ if (!bucket)
+ return;
+
+ hlist_for_each_entry(rt6_ex, &bucket->chain, hlist) {
+ if (!oldest || time_before(rt6_ex->stamp, oldest->stamp))
+ oldest = rt6_ex;
+ }
+ rt6_remove_exception(bucket, oldest);
+}
+
+static u32 rt6_exception_hash(const struct in6_addr *dst,
+ const struct in6_addr *src)
+{
+ static u32 seed __read_mostly;
+ u32 val;
+
+ net_get_random_once(&seed, sizeof(seed));
+ val = jhash(dst, sizeof(*dst), seed);
+
+#ifdef CONFIG_IPV6_SUBTREES
+ if (src)
+ val = jhash(src, sizeof(*src), val);
+#endif
+ return hash_32(val, FIB6_EXCEPTION_BUCKET_SIZE_SHIFT);
+}
+
+/* Helper function to find the cached rt in the hash table
+ * and update bucket pointer to point to the bucket for this
+ * (daddr, saddr) pair
+ * Caller must hold rt6_exception_lock
+ */
+static struct rt6_exception *
+__rt6_find_exception_spinlock(struct rt6_exception_bucket **bucket,
+ const struct in6_addr *daddr,
+ const struct in6_addr *saddr)
+{
+ struct rt6_exception *rt6_ex;
+ u32 hval;
+
+ if (!(*bucket) || !daddr)
+ return NULL;
+
+ hval = rt6_exception_hash(daddr, saddr);
+ *bucket += hval;
+
+ hlist_for_each_entry(rt6_ex, &(*bucket)->chain, hlist) {
+ struct rt6_info *rt6 = rt6_ex->rt6i;
+ bool matched = ipv6_addr_equal(daddr, &rt6->rt6i_dst.addr);
+
+#ifdef CONFIG_IPV6_SUBTREES
+ if (matched && saddr)
+ matched = ipv6_addr_equal(saddr, &rt6->rt6i_src.addr);
+#endif
+ if (matched)
+ return rt6_ex;
+ }
+ return NULL;
+}
+
+/* Helper function to find the cached rt in the hash table
+ * and update bucket pointer to point to the bucket for this
+ * (daddr, saddr) pair
+ * Caller must hold rcu_read_lock()
+ */
+static struct rt6_exception *
+__rt6_find_exception_rcu(struct rt6_exception_bucket **bucket,
+ const struct in6_addr *daddr,
+ const struct in6_addr *saddr)
+{
+ struct rt6_exception *rt6_ex;
+ u32 hval;
+
+ WARN_ON_ONCE(!rcu_read_lock_held());
+
+ if (!(*bucket) || !daddr)
+ return NULL;
+
+ hval = rt6_exception_hash(daddr, saddr);
+ *bucket += hval;
+
+ hlist_for_each_entry_rcu(rt6_ex, &(*bucket)->chain, hlist) {
+ struct rt6_info *rt6 = rt6_ex->rt6i;
+ bool matched = ipv6_addr_equal(daddr, &rt6->rt6i_dst.addr);
+
+#ifdef CONFIG_IPV6_SUBTREES
+ if (matched && saddr)
+ matched = ipv6_addr_equal(saddr, &rt6->rt6i_src.addr);
+#endif
+ if (matched)
+ return rt6_ex;
+ }
+ return NULL;
+}
+
+static int rt6_insert_exception(struct rt6_info *nrt,
+ struct rt6_info *ort)
+{
+ struct rt6_exception_bucket *bucket;
+ struct in6_addr *src_key = NULL;
+ struct rt6_exception *rt6_ex;
+ int err = 0;
+
+ /* ort can't be a cache or pcpu route */
+ if (ort->rt6i_flags & (RTF_CACHE | RTF_PCPU))
+ ort = (struct rt6_info *)ort->dst.from;
+ WARN_ON_ONCE(ort->rt6i_flags & (RTF_CACHE | RTF_PCPU));
+
+ spin_lock_bh(&rt6_exception_lock);
+
+ if (ort->exception_bucket_flushed) {
+ err = -EINVAL;
+ goto out;
+ }
+
+ bucket = rcu_dereference_protected(ort->rt6i_exception_bucket,
+ lockdep_is_held(&rt6_exception_lock));
+ if (!bucket) {
+ bucket = kcalloc(FIB6_EXCEPTION_BUCKET_SIZE, sizeof(*bucket),
+ GFP_ATOMIC);
+ if (!bucket) {
+ err = -ENOMEM;
+ goto out;
+ }
+ rcu_assign_pointer(ort->rt6i_exception_bucket, bucket);
+ }
+
+#ifdef CONFIG_IPV6_SUBTREES
+ /* rt6i_src.plen != 0 indicates ort is in subtree
+ * and exception table is indexed by a hash of
+ * both rt6i_dst and rt6i_src.
+ * Otherwise, the exception table is indexed by
+ * a hash of only rt6i_dst.
+ */
+ if (ort->rt6i_src.plen)
+ src_key = &nrt->rt6i_src.addr;
+#endif
+ rt6_ex = __rt6_find_exception_spinlock(&bucket, &nrt->rt6i_dst.addr,
+ src_key);
+ if (rt6_ex)
+ rt6_remove_exception(bucket, rt6_ex);
+
+ rt6_ex = kzalloc(sizeof(*rt6_ex), GFP_ATOMIC);
+ if (!rt6_ex) {
+ err = -ENOMEM;
+ goto out;
+ }
+ rt6_ex->rt6i = nrt;
+ rt6_ex->stamp = jiffies;
+ atomic_inc(&nrt->rt6i_ref);
+ nrt->rt6i_node = ort->rt6i_node;
+ hlist_add_head_rcu(&rt6_ex->hlist, &bucket->chain);
+ bucket->depth++;
+
+ if (bucket->depth > FIB6_MAX_DEPTH)
+ rt6_exception_remove_oldest(bucket);
+
+out:
+ spin_unlock_bh(&rt6_exception_lock);
+
+ /* Update fn->fn_sernum to invalidate all cached dst */
+ if (!err)
+ fib6_update_sernum(ort);
+
+ return err;
+}
+
+void rt6_flush_exceptions(struct rt6_info *rt)
+{
+ struct rt6_exception_bucket *bucket;
+ struct rt6_exception *rt6_ex;
+ struct hlist_node *tmp;
+ int i;
+
+ spin_lock_bh(&rt6_exception_lock);
+ /* Prevent rt6_insert_exception() to recreate the bucket list */
+ rt->exception_bucket_flushed = 1;
+
+ bucket = rcu_dereference_protected(rt->rt6i_exception_bucket,
+ lockdep_is_held(&rt6_exception_lock));
+ if (!bucket)
+ goto out;
+
+ for (i = 0; i < FIB6_EXCEPTION_BUCKET_SIZE; i++) {
+ hlist_for_each_entry_safe(rt6_ex, tmp, &bucket->chain, hlist)
+ rt6_remove_exception(bucket, rt6_ex);
+ WARN_ON_ONCE(bucket->depth);
+ bucket++;
+ }
+
+out:
+ spin_unlock_bh(&rt6_exception_lock);
+}
+
+/* Find cached rt in the hash table inside passed in rt
+ * Caller has to hold rcu_read_lock()
+ */
+static struct rt6_info *rt6_find_cached_rt(struct rt6_info *rt,
+ struct in6_addr *daddr,
+ struct in6_addr *saddr)
+{
+ struct rt6_exception_bucket *bucket;
+ struct in6_addr *src_key = NULL;
+ struct rt6_exception *rt6_ex;
+ struct rt6_info *res = NULL;
+
+ bucket = rcu_dereference(rt->rt6i_exception_bucket);
+
+#ifdef CONFIG_IPV6_SUBTREES
+ /* rt6i_src.plen != 0 indicates rt is in subtree
+ * and exception table is indexed by a hash of
+ * both rt6i_dst and rt6i_src.
+ * Otherwise, the exception table is indexed by
+ * a hash of only rt6i_dst.
+ */
+ if (rt->rt6i_src.plen)
+ src_key = saddr;
+#endif
+ rt6_ex = __rt6_find_exception_rcu(&bucket, daddr, src_key);
+
+ if (rt6_ex && !rt6_check_expired(rt6_ex->rt6i))
+ res = rt6_ex->rt6i;
+
+ return res;
+}
+
+/* Remove the passed in cached rt from the hash table that contains it */
+int rt6_remove_exception_rt(struct rt6_info *rt)
+{
+ struct rt6_info *from = (struct rt6_info *)rt->dst.from;
+ struct rt6_exception_bucket *bucket;
+ struct in6_addr *src_key = NULL;
+ struct rt6_exception *rt6_ex;
+ int err;
+
+ if (!from ||
+ !(rt->rt6i_flags | RTF_CACHE))
+ return -EINVAL;
+
+ if (!rcu_access_pointer(from->rt6i_exception_bucket))
+ return -ENOENT;
+
+ spin_lock_bh(&rt6_exception_lock);
+ bucket = rcu_dereference_protected(from->rt6i_exception_bucket,
+ lockdep_is_held(&rt6_exception_lock));
+#ifdef CONFIG_IPV6_SUBTREES
+ /* rt6i_src.plen != 0 indicates 'from' is in subtree
+ * and exception table is indexed by a hash of
+ * both rt6i_dst and rt6i_src.
+ * Otherwise, the exception table is indexed by
+ * a hash of only rt6i_dst.
+ */
+ if (from->rt6i_src.plen)
+ src_key = &rt->rt6i_src.addr;
+#endif
+ rt6_ex = __rt6_find_exception_spinlock(&bucket,
+ &rt->rt6i_dst.addr,
+ src_key);
+ if (rt6_ex) {
+ rt6_remove_exception(bucket, rt6_ex);
+ err = 0;
+ } else {
+ err = -ENOENT;
+ }
+
+ spin_unlock_bh(&rt6_exception_lock);
+ return err;
+}
+
+/* Find rt6_ex which contains the passed in rt cache and
+ * refresh its stamp
+ */
+static void rt6_update_exception_stamp_rt(struct rt6_info *rt)
+{
+ struct rt6_info *from = (struct rt6_info *)rt->dst.from;
+ struct rt6_exception_bucket *bucket;
+ struct in6_addr *src_key = NULL;
+ struct rt6_exception *rt6_ex;
+
+ if (!from ||
+ !(rt->rt6i_flags | RTF_CACHE))
+ return;
+
+ rcu_read_lock();
+ bucket = rcu_dereference(from->rt6i_exception_bucket);
+
+#ifdef CONFIG_IPV6_SUBTREES
+ /* rt6i_src.plen != 0 indicates 'from' is in subtree
+ * and exception table is indexed by a hash of
+ * both rt6i_dst and rt6i_src.
+ * Otherwise, the exception table is indexed by
+ * a hash of only rt6i_dst.
+ */
+ if (from->rt6i_src.plen)
+ src_key = &rt->rt6i_src.addr;
+#endif
+ rt6_ex = __rt6_find_exception_rcu(&bucket,
+ &rt->rt6i_dst.addr,
+ src_key);
+ if (rt6_ex)
+ rt6_ex->stamp = jiffies;
+
+ rcu_read_unlock();
+}
+
struct rt6_info *ip6_pol_route(struct net *net, struct fib6_table *table,
int oif, struct flowi6 *fl6, int flags)
{
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