3  * net/core/dst.c	Protocol independent destination cache.
27 #include <net/dst.h>
47 void dst_init(struct dst_entry *dst, struct dst_ops *ops,  in dst_init()  argument
51 	dst->dev = dev;  in dst_init()
52 	netdev_hold(dev, &dst->dev_tracker, GFP_ATOMIC);  in dst_init()
53 	dst->ops = ops;  in dst_init()
54 	dst_init_metrics(dst, dst_default_metrics.metrics, true);  in dst_init()
55 	dst->expires = 0UL;  in dst_init()
57 	dst->xfrm = NULL;  in dst_init()
59 	dst->input = dst_discard;  in dst_init()
60 	dst->output = dst_discard_out;  in dst_init()
61 	dst->error = 0;  in dst_init()
62 	dst->obsolete = initial_obsolete;  in dst_init()
63 	dst->header_len = 0;  in dst_init()
64 	dst->trailer_len = 0;  in dst_init()
66 	dst->tclassid = 0;  in dst_init()
68 	dst->lwtstate = NULL;  in dst_init()
69 	rcuref_init(&dst->__rcuref, 1);  in dst_init()
70 	INIT_LIST_HEAD(&dst->rt_uncached);  in dst_init()
71 	dst->rt_uncached_list = NULL;  in dst_init()
72 	dst->__use = 0;  in dst_init()
73 	dst->lastuse = jiffies;  in dst_init()
74 	dst->flags = flags;  in dst_init()
83 	struct dst_entry *dst;  in dst_alloc()  local
90 	dst = kmem_cache_alloc(ops->kmem_cachep, GFP_ATOMIC);  in dst_alloc()
91 	if (!dst)  in dst_alloc()
94 	dst_init(dst, ops, dev, initial_obsolete, flags);  in dst_alloc()
96 	return dst;  in dst_alloc()
100 static void dst_destroy(struct dst_entry *dst)  in dst_destroy()  argument
107 	if (dst->xfrm) {  in dst_destroy()
108 		struct xfrm_dst *xdst = (struct xfrm_dst *) dst;  in dst_destroy()
113 	if (dst->ops->destroy)  in dst_destroy()
114 		dst->ops->destroy(dst);  in dst_destroy()
115 	netdev_put(dst->dev, &dst->dev_tracker);  in dst_destroy()
117 	lwtstate_put(dst->lwtstate);  in dst_destroy()
119 	if (dst->flags & DST_METADATA)  in dst_destroy()
120 		metadata_dst_free((struct metadata_dst *)dst);  in dst_destroy()
122 		kmem_cache_free(dst->ops->kmem_cachep, dst);  in dst_destroy()
124 	dst = child;  in dst_destroy()
125 	if (dst)  in dst_destroy()
126 		dst_release_immediate(dst);  in dst_destroy()
131 	struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head);  in dst_destroy_rcu()  local
133 	dst_destroy(dst);  in dst_destroy_rcu()
136 /* Operations to mark dst as DEAD and clean up the net device referenced
137  * by dst:
138  * 1. put the dst under blackhole interface and discard all tx/rx packets
145 void dst_dev_put(struct dst_entry *dst)  in dst_dev_put()  argument
147 	struct net_device *dev = dst->dev;  in dst_dev_put()
149 	WRITE_ONCE(dst->obsolete, DST_OBSOLETE_DEAD);  in dst_dev_put()
150 	if (dst->ops->ifdown)  in dst_dev_put()
151 		dst->ops->ifdown(dst, dev);  in dst_dev_put()
152 	WRITE_ONCE(dst->input, dst_discard);  in dst_dev_put()
153 	WRITE_ONCE(dst->output, dst_discard_out);  in dst_dev_put()
154 	rcu_assign_pointer(dst->dev_rcu, blackhole_netdev);  in dst_dev_put()
155 	netdev_ref_replace(dev, blackhole_netdev, &dst->dev_tracker,  in dst_dev_put()
160 static void dst_count_dec(struct dst_entry *dst)  in dst_count_dec()  argument
162 	if (!(dst->flags & DST_NOCOUNT))  in dst_count_dec()
163 		dst_entries_add(dst->ops, -1);  in dst_count_dec()
166 void dst_release(struct dst_entry *dst)  in dst_release()  argument
168 	if (dst && rcuref_put(&dst->__rcuref)) {  in dst_release()
170 		if (dst->flags & DST_METADATA) {  in dst_release()
171 			struct metadata_dst *md_dst = (struct metadata_dst *)dst;  in dst_release()
177 		dst_count_dec(dst);  in dst_release()
178 		call_rcu_hurry(&dst->rcu_head, dst_destroy_rcu);  in dst_release()
183 void dst_release_immediate(struct dst_entry *dst)  in dst_release_immediate()  argument
185 	if (dst && rcuref_put(&dst->__rcuref)) {  in dst_release_immediate()
186 		dst_count_dec(dst);  in dst_release_immediate()
187 		dst_destroy(dst);  in dst_release_immediate()
192 u32 *dst_cow_metrics_generic(struct dst_entry *dst, unsigned long old)  in dst_cow_metrics_generic()  argument
204 		prev = cmpxchg(&dst->_metrics, old, new);  in dst_cow_metrics_generic()
221 /* Caller asserts that dst_metrics_read_only(dst) is false.  */
222 void __dst_destroy_metrics_generic(struct dst_entry *dst, unsigned long old)  in __dst_destroy_metrics_generic()  argument
227 	prev = cmpxchg(&dst->_metrics, old, new);  in __dst_destroy_metrics_generic()
233 struct dst_entry *dst_blackhole_check(struct dst_entry *dst, u32 cookie)  in dst_blackhole_check()  argument
238 u32 *dst_blackhole_cow_metrics(struct dst_entry *dst, unsigned long old)  in dst_blackhole_cow_metrics()  argument
243 struct neighbour *dst_blackhole_neigh_lookup(const struct dst_entry *dst,  in dst_blackhole_neigh_lookup()  argument
250 void dst_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,  in dst_blackhole_update_pmtu()  argument
257 void dst_blackhole_redirect(struct dst_entry *dst, struct sock *sk,  in dst_blackhole_redirect()  argument
263 unsigned int dst_blackhole_mtu(const struct dst_entry *dst)  in dst_blackhole_mtu()  argument
265 	unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);  in dst_blackhole_mtu()
267 	return mtu ? : dst_dev(dst)->mtu;  in dst_blackhole_mtu()
284 	struct dst_entry *dst;  in __metadata_dst_init()  local
286 	dst = &md_dst->dst;  in __metadata_dst_init()
287 	dst_init(dst, &dst_blackhole_ops, NULL, DST_OBSOLETE_NONE,  in __metadata_dst_init()
289 	memset(dst + 1, 0, sizeof(*md_dst) + optslen - sizeof(*dst));  in __metadata_dst_init()