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Diffstat (limited to '')
| -rw-r--r-- | include/net/dst.h | 542 |
1 files changed, 542 insertions, 0 deletions
diff --git a/include/net/dst.h b/include/net/dst.h new file mode 100644 index 000000000..48e613420 --- /dev/null +++ b/include/net/dst.h @@ -0,0 +1,542 @@ +/* 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_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) +{ + DEV_STATS_INC(dev, rx_packets); + DEV_STATS_ADD(dev, 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); +} + +struct dst_entry *dst_blackhole_check(struct dst_entry *dst, u32 cookie); +void dst_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk, + struct sk_buff *skb, u32 mtu, bool confirm_neigh); +void dst_blackhole_redirect(struct dst_entry *dst, struct sock *sk, + struct sk_buff *skb); +u32 *dst_blackhole_cow_metrics(struct dst_entry *dst, unsigned long old); +struct neighbour *dst_blackhole_neigh_lookup(const struct dst_entry *dst, + struct sk_buff *skb, + const void *daddr); +unsigned int dst_blackhole_mtu(const struct dst_entry *dst); + +#endif /* _NET_DST_H */ |