| /* SPDX-License-Identifier: GPL-2.0 */ |
| /* |
| * net/dst.h Protocol independent destination cache definitions. |
| * |
| * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> |
| * |
| */ |
| |
| #ifndef _NET_DST_H |
| #define _NET_DST_H |
| |
| #include <net/dst_ops.h> |
| #include <linux/netdevice.h> |
| #include <linux/rtnetlink.h> |
| #include <linux/rcupdate.h> |
| #include <linux/bug.h> |
| #include <linux/jiffies.h> |
| #include <linux/refcount.h> |
| #include <net/neighbour.h> |
| #include <asm/processor.h> |
| |
| struct sk_buff; |
| |
| struct dst_entry { |
| struct net_device *dev; |
| struct dst_ops *ops; |
| unsigned long _metrics; |
| unsigned long expires; |
| #ifdef CONFIG_XFRM |
| struct xfrm_state *xfrm; |
| #else |
| void *__pad1; |
| #endif |
| int (*input)(struct sk_buff *); |
| int (*output)(struct net *net, struct sock *sk, struct sk_buff *skb); |
| |
| unsigned short flags; |
| #define DST_HOST 0x0001 |
| #define DST_NOXFRM 0x0002 |
| #define DST_NOPOLICY 0x0004 |
| #define DST_NOCOUNT 0x0008 |
| #define DST_FAKE_RTABLE 0x0010 |
| #define DST_XFRM_TUNNEL 0x0020 |
| #define DST_XFRM_QUEUE 0x0040 |
| #define DST_METADATA 0x0080 |
| |
| /* A non-zero value of dst->obsolete forces by-hand validation |
| * of the route entry. Positive values are set by the generic |
| * dst layer to indicate that the entry has been forcefully |
| * destroyed. |
| * |
| * Negative values are used by the implementation layer code to |
| * force invocation of the dst_ops->check() method. |
| */ |
| short obsolete; |
| #define DST_OBSOLETE_NONE 0 |
| #define DST_OBSOLETE_DEAD 2 |
| #define DST_OBSOLETE_FORCE_CHK -1 |
| #define DST_OBSOLETE_KILL -2 |
| unsigned short header_len; /* more space at head required */ |
| unsigned short trailer_len; /* space to reserve at tail */ |
| |
| /* |
| * __refcnt wants to be on a different cache line from |
| * input/output/ops or performance tanks badly |
| */ |
| #ifdef CONFIG_64BIT |
| atomic_t __refcnt; /* 64-bit offset 64 */ |
| #endif |
| int __use; |
| unsigned long lastuse; |
| struct lwtunnel_state *lwtstate; |
| struct rcu_head rcu_head; |
| short error; |
| short __pad; |
| __u32 tclassid; |
| #ifndef CONFIG_64BIT |
| atomic_t __refcnt; /* 32-bit offset 64 */ |
| #endif |
| }; |
| |
| struct dst_metrics { |
| u32 metrics[RTAX_MAX]; |
| refcount_t refcnt; |
| } __aligned(4); /* Low pointer bits contain DST_METRICS_FLAGS */ |
| extern const struct dst_metrics dst_default_metrics; |
| |
| u32 *dst_cow_metrics_generic(struct dst_entry *dst, unsigned long old); |
| |
| #define DST_METRICS_READ_ONLY 0x1UL |
| #define DST_METRICS_REFCOUNTED 0x2UL |
| #define DST_METRICS_FLAGS 0x3UL |
| #define __DST_METRICS_PTR(Y) \ |
| ((u32 *)((Y) & ~DST_METRICS_FLAGS)) |
| #define DST_METRICS_PTR(X) __DST_METRICS_PTR((X)->_metrics) |
| |
| static inline bool dst_metrics_read_only(const struct dst_entry *dst) |
| { |
| return dst->_metrics & DST_METRICS_READ_ONLY; |
| } |
| |
| void __dst_destroy_metrics_generic(struct dst_entry *dst, unsigned long old); |
| |
| static inline void dst_destroy_metrics_generic(struct dst_entry *dst) |
| { |
| unsigned long val = dst->_metrics; |
| if (!(val & DST_METRICS_READ_ONLY)) |
| __dst_destroy_metrics_generic(dst, val); |
| } |
| |
| static inline u32 *dst_metrics_write_ptr(struct dst_entry *dst) |
| { |
| unsigned long p = dst->_metrics; |
| |
| BUG_ON(!p); |
| |
| if (p & DST_METRICS_READ_ONLY) |
| return dst->ops->cow_metrics(dst, p); |
| return __DST_METRICS_PTR(p); |
| } |
| |
| /* This may only be invoked before the entry has reached global |
| * visibility. |
| */ |
| static inline void dst_init_metrics(struct dst_entry *dst, |
| const u32 *src_metrics, |
| bool read_only) |
| { |
| dst->_metrics = ((unsigned long) src_metrics) | |
| (read_only ? DST_METRICS_READ_ONLY : 0); |
| } |
| |
| static inline void dst_copy_metrics(struct dst_entry *dest, const struct dst_entry *src) |
| { |
| u32 *dst_metrics = dst_metrics_write_ptr(dest); |
| |
| if (dst_metrics) { |
| u32 *src_metrics = DST_METRICS_PTR(src); |
| |
| memcpy(dst_metrics, src_metrics, RTAX_MAX * sizeof(u32)); |
| } |
| } |
| |
| static inline u32 *dst_metrics_ptr(struct dst_entry *dst) |
| { |
| return DST_METRICS_PTR(dst); |
| } |
| |
| static inline u32 |
| dst_metric_raw(const struct dst_entry *dst, const int metric) |
| { |
| u32 *p = DST_METRICS_PTR(dst); |
| |
| return p[metric-1]; |
| } |
| |
| static inline u32 |
| dst_metric(const struct dst_entry *dst, const int metric) |
| { |
| WARN_ON_ONCE(metric == RTAX_HOPLIMIT || |
| metric == RTAX_ADVMSS || |
| metric == RTAX_MTU); |
| return dst_metric_raw(dst, metric); |
| } |
| |
| static inline u32 |
| dst_metric_advmss(const struct dst_entry *dst) |
| { |
| u32 advmss = dst_metric_raw(dst, RTAX_ADVMSS); |
| |
| if (!advmss) |
| advmss = dst->ops->default_advmss(dst); |
| |
| return advmss; |
| } |
| |
| static inline void dst_metric_set(struct dst_entry *dst, int metric, u32 val) |
| { |
| u32 *p = dst_metrics_write_ptr(dst); |
| |
| if (p) |
| p[metric-1] = val; |
| } |
| |
| /* Kernel-internal feature bits that are unallocated in user space. */ |
| #define DST_FEATURE_ECN_CA (1U << 31) |
| |
| #define DST_FEATURE_MASK (DST_FEATURE_ECN_CA) |
| #define DST_FEATURE_ECN_MASK (DST_FEATURE_ECN_CA | RTAX_FEATURE_ECN) |
| |
| static inline u32 |
| dst_feature(const struct dst_entry *dst, u32 feature) |
| { |
| return dst_metric(dst, RTAX_FEATURES) & feature; |
| } |
| |
| static inline u32 dst_mtu(const struct dst_entry *dst) |
| { |
| return dst->ops->mtu(dst); |
| } |
| |
| /* RTT metrics are stored in milliseconds for user ABI, but used as jiffies */ |
| static inline unsigned long dst_metric_rtt(const struct dst_entry *dst, int metric) |
| { |
| return msecs_to_jiffies(dst_metric(dst, metric)); |
| } |
| |
| static inline u32 |
| dst_allfrag(const struct dst_entry *dst) |
| { |
| int ret = dst_feature(dst, RTAX_FEATURE_ALLFRAG); |
| return ret; |
| } |
| |
| static inline int |
| dst_metric_locked(const struct dst_entry *dst, int metric) |
| { |
| return dst_metric(dst, RTAX_LOCK) & (1<<metric); |
| } |
| |
| static inline void dst_hold(struct dst_entry *dst) |
| { |
| /* |
| * If your kernel compilation stops here, please check |
| * the placement of __refcnt in struct dst_entry |
| */ |
| BUILD_BUG_ON(offsetof(struct dst_entry, __refcnt) & 63); |
| WARN_ON(atomic_inc_not_zero(&dst->__refcnt) == 0); |
| } |
| |
| static inline void dst_use_noref(struct dst_entry *dst, unsigned long time) |
| { |
| if (unlikely(time != dst->lastuse)) { |
| dst->__use++; |
| dst->lastuse = time; |
| } |
| } |
| |
| static inline struct dst_entry *dst_clone(struct dst_entry *dst) |
| { |
| if (dst) |
| dst_hold(dst); |
| return dst; |
| } |
| |
| void dst_release(struct dst_entry *dst); |
| |
| void dst_release_immediate(struct dst_entry *dst); |
| |
| static inline void refdst_drop(unsigned long refdst) |
| { |
| if (!(refdst & SKB_DST_NOREF)) |
| dst_release((struct dst_entry *)(refdst & SKB_DST_PTRMASK)); |
| } |
| |
| /** |
| * skb_dst_drop - drops skb dst |
| * @skb: buffer |
| * |
| * Drops dst reference count if a reference was taken. |
| */ |
| static inline void skb_dst_drop(struct sk_buff *skb) |
| { |
| if (skb->_skb_refdst) { |
| refdst_drop(skb->_skb_refdst); |
| skb->_skb_refdst = 0UL; |
| } |
| } |
| |
| static inline void __skb_dst_copy(struct sk_buff *nskb, unsigned long refdst) |
| { |
| nskb->_skb_refdst = refdst; |
| if (!(nskb->_skb_refdst & SKB_DST_NOREF)) |
| dst_clone(skb_dst(nskb)); |
| } |
| |
| static inline void skb_dst_copy(struct sk_buff *nskb, const struct sk_buff *oskb) |
| { |
| __skb_dst_copy(nskb, oskb->_skb_refdst); |
| } |
| |
| /** |
| * dst_hold_safe - Take a reference on a dst if possible |
| * @dst: pointer to dst entry |
| * |
| * This helper returns false if it could not safely |
| * take a reference on a dst. |
| */ |
| static inline bool dst_hold_safe(struct dst_entry *dst) |
| { |
| return atomic_inc_not_zero(&dst->__refcnt); |
| } |
| |
| /** |
| * skb_dst_force - makes sure skb dst is refcounted |
| * @skb: buffer |
| * |
| * If dst is not yet refcounted and not destroyed, grab a ref on it. |
| * Returns true if dst is refcounted. |
| */ |
| static inline bool skb_dst_force(struct sk_buff *skb) |
| { |
| if (skb_dst_is_noref(skb)) { |
| struct dst_entry *dst = skb_dst(skb); |
| |
| WARN_ON(!rcu_read_lock_held()); |
| if (!dst_hold_safe(dst)) |
| dst = NULL; |
| |
| skb->_skb_refdst = (unsigned long)dst; |
| } |
| |
| return skb->_skb_refdst != 0UL; |
| } |
| |
| |
| /** |
| * __skb_tunnel_rx - prepare skb for rx reinsert |
| * @skb: buffer |
| * @dev: tunnel device |
| * @net: netns for packet i/o |
| * |
| * After decapsulation, packet is going to re-enter (netif_rx()) our stack, |
| * so make some cleanups. (no accounting done) |
| */ |
| static inline void __skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev, |
| struct net *net) |
| { |
| skb->dev = dev; |
| |
| /* |
| * Clear hash so that we can recalulate the hash for the |
| * encapsulated packet, unless we have already determine the hash |
| * over the L4 4-tuple. |
| */ |
| skb_clear_hash_if_not_l4(skb); |
| skb_set_queue_mapping(skb, 0); |
| skb_scrub_packet(skb, !net_eq(net, dev_net(dev))); |
| } |
| |
| /** |
| * skb_tunnel_rx - prepare skb for rx reinsert |
| * @skb: buffer |
| * @dev: tunnel device |
| * @net: netns for packet i/o |
| * |
| * After decapsulation, packet is going to re-enter (netif_rx()) our stack, |
| * so make some cleanups, and perform accounting. |
| * Note: this accounting is not SMP safe. |
| */ |
| static inline void skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev, |
| struct net *net) |
| { |
| /* TODO : stats should be SMP safe */ |
| dev->stats.rx_packets++; |
| dev->stats.rx_bytes += skb->len; |
| __skb_tunnel_rx(skb, dev, net); |
| } |
| |
| static inline u32 dst_tclassid(const struct sk_buff *skb) |
| { |
| #ifdef CONFIG_IP_ROUTE_CLASSID |
| const struct dst_entry *dst; |
| |
| dst = skb_dst(skb); |
| if (dst) |
| return dst->tclassid; |
| #endif |
| return 0; |
| } |
| |
| int dst_discard_out(struct net *net, struct sock *sk, struct sk_buff *skb); |
| static inline int dst_discard(struct sk_buff *skb) |
| { |
| return dst_discard_out(&init_net, skb->sk, skb); |
| } |
| void *dst_alloc(struct dst_ops *ops, struct net_device *dev, int initial_ref, |
| int initial_obsolete, unsigned short flags); |
| void dst_init(struct dst_entry *dst, struct dst_ops *ops, |
| struct net_device *dev, int initial_ref, int initial_obsolete, |
| unsigned short flags); |
| struct dst_entry *dst_destroy(struct dst_entry *dst); |
| void dst_dev_put(struct dst_entry *dst); |
| |
| static inline void dst_confirm(struct dst_entry *dst) |
| { |
| } |
| |
| static inline struct neighbour *dst_neigh_lookup(const struct dst_entry *dst, const void *daddr) |
| { |
| struct neighbour *n = dst->ops->neigh_lookup(dst, NULL, daddr); |
| return IS_ERR(n) ? NULL : n; |
| } |
| |
| static inline struct neighbour *dst_neigh_lookup_skb(const struct dst_entry *dst, |
| struct sk_buff *skb) |
| { |
| struct neighbour *n = NULL; |
| |
| /* The packets from tunnel devices (eg bareudp) may have only |
| * metadata in the dst pointer of skb. Hence a pointer check of |
| * neigh_lookup is needed. |
| */ |
| if (dst->ops->neigh_lookup) |
| n = dst->ops->neigh_lookup(dst, skb, NULL); |
| |
| return IS_ERR(n) ? NULL : n; |
| } |
| |
| static inline void dst_confirm_neigh(const struct dst_entry *dst, |
| const void *daddr) |
| { |
| if (dst->ops->confirm_neigh) |
| dst->ops->confirm_neigh(dst, daddr); |
| } |
| |
| static inline void dst_link_failure(struct sk_buff *skb) |
| { |
| struct dst_entry *dst = skb_dst(skb); |
| if (dst && dst->ops && dst->ops->link_failure) |
| dst->ops->link_failure(skb); |
| } |
| |
| static inline void dst_set_expires(struct dst_entry *dst, int timeout) |
| { |
| unsigned long expires = jiffies + timeout; |
| |
| if (expires == 0) |
| expires = 1; |
| |
| if (dst->expires == 0 || time_before(expires, dst->expires)) |
| dst->expires = expires; |
| } |
| |
| /* Output packet to network from transport. */ |
| static inline int dst_output(struct net *net, struct sock *sk, struct sk_buff *skb) |
| { |
| return skb_dst(skb)->output(net, sk, skb); |
| } |
| |
| /* Input packet from network to transport. */ |
| static inline int dst_input(struct sk_buff *skb) |
| { |
| return skb_dst(skb)->input(skb); |
| } |
| |
| static inline struct dst_entry *dst_check(struct dst_entry *dst, u32 cookie) |
| { |
| if (dst->obsolete) |
| dst = dst->ops->check(dst, cookie); |
| return dst; |
| } |
| |
| /* Flags for xfrm_lookup flags argument. */ |
| enum { |
| XFRM_LOOKUP_ICMP = 1 << 0, |
| XFRM_LOOKUP_QUEUE = 1 << 1, |
| XFRM_LOOKUP_KEEP_DST_REF = 1 << 2, |
| }; |
| |
| struct flowi; |
| #ifndef CONFIG_XFRM |
| static inline struct dst_entry *xfrm_lookup(struct net *net, |
| struct dst_entry *dst_orig, |
| const struct flowi *fl, |
| const struct sock *sk, |
| int flags) |
| { |
| return dst_orig; |
| } |
| |
| static inline struct dst_entry * |
| xfrm_lookup_with_ifid(struct net *net, struct dst_entry *dst_orig, |
| const struct flowi *fl, const struct sock *sk, |
| int flags, u32 if_id) |
| { |
| return dst_orig; |
| } |
| |
| static inline struct dst_entry *xfrm_lookup_route(struct net *net, |
| struct dst_entry *dst_orig, |
| const struct flowi *fl, |
| const struct sock *sk, |
| int flags) |
| { |
| return dst_orig; |
| } |
| |
| static inline struct xfrm_state *dst_xfrm(const struct dst_entry *dst) |
| { |
| return NULL; |
| } |
| |
| #else |
| struct dst_entry *xfrm_lookup(struct net *net, struct dst_entry *dst_orig, |
| const struct flowi *fl, const struct sock *sk, |
| int flags); |
| |
| struct dst_entry *xfrm_lookup_with_ifid(struct net *net, |
| struct dst_entry *dst_orig, |
| const struct flowi *fl, |
| const struct sock *sk, int flags, |
| u32 if_id); |
| |
| struct dst_entry *xfrm_lookup_route(struct net *net, struct dst_entry *dst_orig, |
| const struct flowi *fl, const struct sock *sk, |
| int flags); |
| |
| /* skb attached with this dst needs transformation if dst->xfrm is valid */ |
| static inline struct xfrm_state *dst_xfrm(const struct dst_entry *dst) |
| { |
| return dst->xfrm; |
| } |
| #endif |
| |
| static inline void skb_dst_update_pmtu(struct sk_buff *skb, u32 mtu) |
| { |
| struct dst_entry *dst = skb_dst(skb); |
| |
| if (dst && dst->ops->update_pmtu) |
| dst->ops->update_pmtu(dst, NULL, skb, mtu, true); |
| } |
| |
| /* update dst pmtu but not do neighbor confirm */ |
| static inline void skb_dst_update_pmtu_no_confirm(struct sk_buff *skb, u32 mtu) |
| { |
| struct dst_entry *dst = skb_dst(skb); |
| |
| if (dst && dst->ops->update_pmtu) |
| dst->ops->update_pmtu(dst, NULL, skb, mtu, false); |
| } |
| |
| static inline void skb_tunnel_check_pmtu(struct sk_buff *skb, |
| struct dst_entry *encap_dst, |
| int headroom) |
| { |
| u32 encap_mtu = dst_mtu(encap_dst); |
| |
| if (skb->len > encap_mtu - headroom) |
| skb_dst_update_pmtu_no_confirm(skb, encap_mtu - headroom); |
| } |
| |
| #endif /* _NET_DST_H */ |