Something went wrong. Try again.
Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Something went wrong. Try again.
123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356// SPDX-License-Identifier: GPL-2.0-only/* * net/core/dst.c Protocol independent destination cache. * * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> * */
#include <linux/bitops.h>#include <linux/errno.h>#include <linux/init.h>#include <linux/kernel.h>#include <linux/workqueue.h>#include <linux/mm.h>#include <linux/module.h>#include <linux/slab.h>#include <linux/netdevice.h>#include <linux/skbuff.h>#include <linux/string.h>#include <linux/types.h>#include <net/net_namespace.h>#include <linux/sched.h>#include <linux/prefetch.h>#include <net/lwtunnel.h>#include <net/xfrm.h>
#include <net/dst.h>#include <net/dst_metadata.h>
int dst_discard_out(struct net *net, struct sock *sk, struct sk_buff *skb){ kfree_skb(skb); return 0;}EXPORT_SYMBOL(dst_discard_out);
const struct dst_metrics dst_default_metrics = { /* This initializer is needed to force linker to place this variable * into const section. Otherwise it might end into bss section. * We really want to avoid false sharing on this variable, and catch * any writes on it. */ .refcnt = REFCOUNT_INIT(1),};EXPORT_SYMBOL(dst_default_metrics);
void dst_init(struct dst_entry *dst, struct dst_ops *ops, struct net_device *dev, int initial_obsolete, unsigned short flags){ dst->dev = dev; netdev_hold(dev, &dst->dev_tracker, GFP_ATOMIC); dst->ops = ops; dst_init_metrics(dst, dst_default_metrics.metrics, true); dst->expires = 0UL;#ifdef CONFIG_XFRM dst->xfrm = NULL;#endif dst->input = dst_discard; dst->output = dst_discard_out; dst->error = 0; dst->obsolete = initial_obsolete; dst->header_len = 0; dst->trailer_len = 0;#ifdef CONFIG_IP_ROUTE_CLASSID dst->tclassid = 0;#endif dst->lwtstate = NULL; rcuref_init(&dst->__rcuref, 1); INIT_LIST_HEAD(&dst->rt_uncached); dst->rt_uncached_list = NULL; dst->__use = 0; dst->lastuse = jiffies; dst->flags = flags; if (!(flags & DST_NOCOUNT)) dst_entries_add(ops, 1);}EXPORT_SYMBOL(dst_init);
void *dst_alloc(struct dst_ops *ops, struct net_device *dev, int initial_obsolete, unsigned short flags){ struct dst_entry *dst;
if (ops->gc && !(flags & DST_NOCOUNT) && dst_entries_get_fast(ops) > ops->gc_thresh) ops->gc(ops);
dst = kmem_cache_alloc(ops->kmem_cachep, GFP_ATOMIC); if (!dst) return NULL;
dst_init(dst, ops, dev, initial_obsolete, flags);
return dst;}EXPORT_SYMBOL(dst_alloc);
static void dst_destroy(struct dst_entry *dst){ struct dst_entry *child = NULL;
smp_rmb();
#ifdef CONFIG_XFRM if (dst->xfrm) { struct xfrm_dst *xdst = (struct xfrm_dst *) dst;
child = xdst->child; }#endif if (dst->ops->destroy) dst->ops->destroy(dst); netdev_put(dst->dev, &dst->dev_tracker);
lwtstate_put(dst->lwtstate);
if (dst->flags & DST_METADATA) metadata_dst_free((struct metadata_dst *)dst); else kmem_cache_free(dst->ops->kmem_cachep, dst);
dst = child; if (dst) dst_release_immediate(dst);}
static void dst_destroy_rcu(struct rcu_head *head){ struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head);
dst_destroy(dst);}
/* Operations to mark dst as DEAD and clean up the net device referenced * by dst: * 1. put the dst under blackhole interface and discard all tx/rx packets * on this route. * 2. release the net_device * This function should be called when removing routes from the fib tree * in preparation for a NETDEV_DOWN/NETDEV_UNREGISTER event and also to * make the next dst_ops->check() fail. */void dst_dev_put(struct dst_entry *dst){ struct net_device *dev = dst->dev;
WRITE_ONCE(dst->obsolete, DST_OBSOLETE_DEAD); if (dst->ops->ifdown) dst->ops->ifdown(dst, dev); WRITE_ONCE(dst->input, dst_discard); WRITE_ONCE(dst->output, dst_discard_out); rcu_assign_pointer(dst->dev_rcu, blackhole_netdev); netdev_ref_replace(dev, blackhole_netdev, &dst->dev_tracker, GFP_ATOMIC);}EXPORT_SYMBOL(dst_dev_put);
static void dst_count_dec(struct dst_entry *dst){ if (!(dst->flags & DST_NOCOUNT)) dst_entries_add(dst->ops, -1);}
void dst_release(struct dst_entry *dst){ if (dst && rcuref_put(&dst->__rcuref)) {#ifdef CONFIG_DST_CACHE if (dst->flags & DST_METADATA) { struct metadata_dst *md_dst = (struct metadata_dst *)dst;
if (md_dst->type == METADATA_IP_TUNNEL) dst_cache_reset_now(&md_dst->u.tun_info.dst_cache); }#endif dst_count_dec(dst); call_rcu_hurry(&dst->rcu_head, dst_destroy_rcu); }}EXPORT_SYMBOL(dst_release);
void dst_release_immediate(struct dst_entry *dst){ if (dst && rcuref_put(&dst->__rcuref)) { dst_count_dec(dst); dst_destroy(dst); }}EXPORT_SYMBOL(dst_release_immediate);
u32 *dst_cow_metrics_generic(struct dst_entry *dst, unsigned long old){ struct dst_metrics *p = kmalloc_obj(*p, GFP_ATOMIC);
if (p) { struct dst_metrics *old_p = (struct dst_metrics *)__DST_METRICS_PTR(old); unsigned long prev, new;
refcount_set(&p->refcnt, 1); memcpy(p->metrics, old_p->metrics, sizeof(p->metrics));
new = (unsigned long) p; prev = cmpxchg(&dst->_metrics, old, new);
if (prev != old) { kfree(p); p = (struct dst_metrics *)__DST_METRICS_PTR(prev); if (prev & DST_METRICS_READ_ONLY) p = NULL; } else if (prev & DST_METRICS_REFCOUNTED) { if (refcount_dec_and_test(&old_p->refcnt)) kfree(old_p); } } BUILD_BUG_ON(offsetof(struct dst_metrics, metrics) != 0); return (u32 *)p;}EXPORT_SYMBOL(dst_cow_metrics_generic);
/* Caller asserts that dst_metrics_read_only(dst) is false. */void __dst_destroy_metrics_generic(struct dst_entry *dst, unsigned long old){ unsigned long prev, new;
new = ((unsigned long) &dst_default_metrics) | DST_METRICS_READ_ONLY; prev = cmpxchg(&dst->_metrics, old, new); if (prev == old) kfree(__DST_METRICS_PTR(old));}EXPORT_SYMBOL(__dst_destroy_metrics_generic);
struct dst_entry *dst_blackhole_check(struct dst_entry *dst, u32 cookie){ return NULL;}
u32 *dst_blackhole_cow_metrics(struct dst_entry *dst, unsigned long old){ return NULL;}
struct neighbour *dst_blackhole_neigh_lookup(const struct dst_entry *dst, struct sk_buff *skb, const void *daddr){ return NULL;}
void dst_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb, u32 mtu, bool confirm_neigh){}EXPORT_SYMBOL_GPL(dst_blackhole_update_pmtu);
void dst_blackhole_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb){}EXPORT_SYMBOL_GPL(dst_blackhole_redirect);
unsigned int dst_blackhole_mtu(const struct dst_entry *dst){ unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
return mtu ? : dst_dev(dst)->mtu;}EXPORT_SYMBOL_GPL(dst_blackhole_mtu);
static struct dst_ops dst_blackhole_ops = { .family = AF_UNSPEC, .neigh_lookup = dst_blackhole_neigh_lookup, .check = dst_blackhole_check, .cow_metrics = dst_blackhole_cow_metrics, .update_pmtu = dst_blackhole_update_pmtu, .redirect = dst_blackhole_redirect, .mtu = dst_blackhole_mtu,};
static void __metadata_dst_init(struct metadata_dst *md_dst, enum metadata_type type, u8 optslen){ struct dst_entry *dst;
dst = &md_dst->dst; dst_init(dst, &dst_blackhole_ops, NULL, DST_OBSOLETE_NONE, DST_METADATA | DST_NOCOUNT); memset(dst + 1, 0, sizeof(*md_dst) + optslen - sizeof(*dst)); md_dst->type = type;}
struct metadata_dst *metadata_dst_alloc(u8 optslen, enum metadata_type type, gfp_t flags){ struct metadata_dst *md_dst;
md_dst = kmalloc_flex(*md_dst, u.tun_info.options, optslen, flags); if (!md_dst) return NULL;
__metadata_dst_init(md_dst, type, optslen);
return md_dst;}EXPORT_SYMBOL_GPL(metadata_dst_alloc);
void metadata_dst_free(struct metadata_dst *md_dst){#ifdef CONFIG_DST_CACHE if (md_dst->type == METADATA_IP_TUNNEL) dst_cache_destroy(&md_dst->u.tun_info.dst_cache);#endif if (md_dst->type == METADATA_XFRM) dst_release(md_dst->u.xfrm_info.dst_orig); kfree(md_dst);}EXPORT_SYMBOL_GPL(metadata_dst_free);
struct metadata_dst __percpu *metadata_dst_alloc_percpu(u8 optslen, enum metadata_type type, gfp_t flags){ int cpu; struct metadata_dst __percpu *md_dst;
md_dst = __alloc_percpu_gfp(struct_size(md_dst, u.tun_info.options, optslen), __alignof__(struct metadata_dst), flags); if (!md_dst) return NULL;
for_each_possible_cpu(cpu) __metadata_dst_init(per_cpu_ptr(md_dst, cpu), type, optslen);
return md_dst;}EXPORT_SYMBOL_GPL(metadata_dst_alloc_percpu);
void metadata_dst_free_percpu(struct metadata_dst __percpu *md_dst){ int cpu;
for_each_possible_cpu(cpu) { struct metadata_dst *one_md_dst = per_cpu_ptr(md_dst, cpu);
#ifdef CONFIG_DST_CACHE if (one_md_dst->type == METADATA_IP_TUNNEL) dst_cache_destroy(&one_md_dst->u.tun_info.dst_cache);#endif if (one_md_dst->type == METADATA_XFRM) dst_release(one_md_dst->u.xfrm_info.dst_orig); } free_percpu(md_dst);}EXPORT_SYMBOL_GPL(metadata_dst_free_percpu);