Subject: [PATCH RFC net-next 17/20] net/ipv6: introduce fib6_info struct and helpers

From: David Ahern <[email-masked]>
Date: Sun, 25 Feb 2018 11:47:27 -0800

Add fib6_info struct and alloc, destroy, hold and release helpers.

Signed-off-by: David Ahern <[email-masked]>
---
 include/net/ip6_fib.h | 57 ++++++++++++++++++++++++++++++++++++++++++++++++
 net/ipv6/ip6_fib.c    | 60 +++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 117 insertions(+)

diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h
index d867b1696927..70978deac538 100644
--- a/include/net/ip6_fib.h
+++ b/include/net/ip6_fib.h
@@ -38,6 +38,7 @@
 #endif
 
 struct rt6_info;
+struct fib6_info;
 
 struct fib6_config {
 	u32		fc_table;
@@ -132,6 +133,48 @@ struct fib6_nh {
 	int			nh_weight;
 };
 
+struct fib6_info {
+	struct fib6_table		*rt6i_table;
+	struct fib6_info __rcu		*rt6_next;
+	struct fib6_node __rcu		*rt6i_node;
+
+	/* Multipath routes:
+	 * siblings is a list of fib6_info that have the the same metric/weight,
+	 * destination, but not the same gateway. nsiblings is just a cache
+	 * to speed up lookup.
+	 */
+	struct list_head		rt6i_siblings;
+	unsigned int			rt6i_nsiblings;
+
+	atomic_t			rt6i_ref;
+	struct inet6_dev		*rt6i_idev;
+	unsigned long			expires;
+	struct dst_metrics		*fib6_metrics;
+#define fib6_pmtu		fib6_metrics->metrics[RTAX_MTU-1]
+#define fib6_hoplimit		fib6_metrics->metrics[RTAX_HOPLIMIT-1]
+#define fib6_metric_lock	fib6_metrics->metrics[RTAX_LOCK - 1]
+
+	struct rt6key			rt6i_dst;
+	u32				rt6i_flags;
+	struct rt6key			rt6i_src;
+	struct rt6key			rt6i_prefsrc;
+
+	struct rt6_info * __percpu	*rt6i_pcpu;
+	struct rt6_exception_bucket __rcu *rt6i_exception_bucket;
+
+	u32				rt6i_metric;
+	u8				rt6i_protocol;
+	u8				fib6_type;
+	u8				exception_bucket_flushed:1,
+					should_flush:1,
+					dst_nocount:1,
+					dst_nopolicy:1,
+					dst_host:1,
+					unused:3;
+
+	struct fib6_nh			fib6_nh;
+};
+
 struct rt6_info {
 	struct dst_entry		dst;
 	struct rt6_info __rcu		*rt6_next;
@@ -290,6 +333,20 @@ static inline void ip6_rt_put(struct rt6_info *rt)
 
 void rt6_free_pcpu(struct rt6_info *non_pcpu_rt);
 
+struct rt6_info *fib6_info_alloc(gfp_t gfp_flags);
+void fib6_info_destroy(struct rt6_info *f6i);
+
+static inline void fib6_info_hold(struct rt6_info *f6i)
+{
+	atomic_inc(&f6i->rt6i_ref);
+}
+
+static inline void fib6_info_release(struct rt6_info *f6i)
+{
+	if (f6i && atomic_dec_and_test(&f6i->rt6i_ref))
+		fib6_info_destroy(f6i);
+}
+
 static inline void rt6_hold(struct rt6_info *rt)
 {
 	atomic_inc(&rt->rt6i_ref);
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 63a91db61749..6553550bd09b 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -145,6 +145,66 @@ static __be32 addr_bit_set(const void *token, int fn_bit)
 	       addr[fn_bit >> 5];
 }
 
+struct rt6_info *fib6_info_alloc(gfp_t gfp_flags)
+{
+	struct rt6_info *f6i;
+
+	f6i = kzalloc(sizeof(*f6i), gfp_flags);
+	if (!f6i)
+		return NULL;
+
+	f6i->rt6i_pcpu = alloc_percpu_gfp(struct rt6_info *, gfp_flags);
+	if (!f6i->rt6i_pcpu) {
+		kfree(f6i);
+		return NULL;
+	}
+
+	INIT_LIST_HEAD(&f6i->rt6i_siblings);
+	f6i->fib6_metrics = (struct dst_metrics *)&dst_default_metrics;
+
+	atomic_inc(&f6i->rt6i_ref);
+
+	return f6i;
+}
+
+void fib6_info_destroy(struct rt6_info *f6i)
+{
+	struct rt6_exception_bucket *bucket;
+
+	WARN_ON(f6i->rt6i_node);
+
+	bucket = rcu_dereference_protected(f6i->rt6i_exception_bucket, 1);
+	if (bucket) {
+		f6i->rt6i_exception_bucket = NULL;
+		kfree(bucket);
+	}
+
+	if (f6i->rt6i_pcpu) {
+		int cpu;
+
+		for_each_possible_cpu(cpu) {
+			struct rt6_info **ppcpu_rt;
+			struct rt6_info *pcpu_rt;
+
+			ppcpu_rt = per_cpu_ptr(f6i->rt6i_pcpu, cpu);
+			pcpu_rt = *ppcpu_rt;
+			if (pcpu_rt) {
+				dst_dev_put(&pcpu_rt->dst);
+				dst_release(&pcpu_rt->dst);
+				*ppcpu_rt = NULL;
+			}
+		}
+	}
+
+	if (f6i->rt6i_idev)
+		in6_dev_put(f6i->rt6i_idev);
+	if (f6i->fib6_nh.nh_dev)
+		dev_put(f6i->fib6_nh.nh_dev);
+
+	kfree(f6i);
+}
+EXPORT_SYMBOL_GPL(fib6_info_destroy);
+
 static struct fib6_node *node_alloc(struct net *net)
 {
 	struct fib6_node *fn;
-- 
2.11.0