#ifndef __NET_FRAG_H__ #define __NET_FRAG_H__ #include <linux/percpu_counter.h> struct netns_frags { /* The percpu_counter "mem" need to be cacheline aligned. * mem.count must not share cacheline with other writers */ struct percpu_counter mem ____cacheline_aligned_in_smp; /* sysctls */ int timeout; int high_thresh; int low_thresh; int max_dist; }; /** * fragment queue flags * * @INET_FRAG_FIRST_IN: first fragment has arrived * @INET_FRAG_LAST_IN: final fragment has arrived * @INET_FRAG_COMPLETE: frag queue has been processed and is due for destruction */ enum { INET_FRAG_FIRST_IN = BIT(0), INET_FRAG_LAST_IN = BIT(1), INET_FRAG_COMPLETE = BIT(2), }; /** * struct inet_frag_queue - fragment queue * * @lock: spinlock protecting the queue * @timer: queue expiration timer * @list: hash bucket list * @refcnt: reference count of the queue * @fragments: received fragments head * @fragments_tail: received fragments tail * @stamp: timestamp of the last received fragment * @len: total length of the original datagram * @meat: length of received fragments so far * @flags: fragment queue flags * @max_size: maximum received fragment size * @net: namespace that this frag belongs to * @list_evictor: list of queues to forcefully evict (e.g. due to low memory) */ struct inet_frag_queue { spinlock_t lock; struct timer_list timer; struct hlist_node list; atomic_t refcnt; struct sk_buff *fragments; struct sk_buff *fragments_tail; ktime_t stamp; int len; int meat; __u8 flags; u16 max_size; struct netns_frags *net; struct hlist_node list_evictor; }; #define INETFRAGS_HASHSZ 1024 /* averaged: * max_depth = default ipfrag_high_thresh / INETFRAGS_HASHSZ / * rounded up (SKB_TRUELEN(0) + sizeof(struct ipq or * struct frag_queue)) */ #define INETFRAGS_MAXDEPTH 128 struct inet_frag_bucket { struct hlist_head chain; spinlock_t chain_lock; }; struct inet_frags { struct inet_frag_bucket hash[INETFRAGS_HASHSZ]; struct work_struct frags_work; unsigned int next_bucket; unsigned long last_rebuild_jiffies; bool rebuild; /* The first call to hashfn is responsible to initialize * rnd. This is best done with net_get_random_once. * * rnd_seqlock is used to let hash insertion detect * when it needs to re-lookup the hash chain to use. */ u32 rnd; seqlock_t rnd_seqlock; int qsize; unsigned int (*hashfn)(const struct inet_frag_queue *); bool (*match)(const struct inet_frag_queue *q, const void *arg); void (*constructor)(struct inet_frag_queue *q, const void *arg); void (*destructor)(struct inet_frag_queue *); void (*frag_expire)(unsigned long data); struct kmem_cache *frags_cachep; const char *frags_cache_name; }; int inet_frags_init(struct inet_frags *); void inet_frags_fini(struct inet_frags *); static inline int inet_frags_init_net(struct netns_frags *nf) { return percpu_counter_init(&nf->mem, 0, GFP_KERNEL); } static inline void inet_frags_uninit_net(struct netns_frags *nf) { percpu_counter_destroy(&nf->mem); } void inet_frags_exit_net(struct netns_frags *nf, struct inet_frags *f); void inet_frag_kill(struct inet_frag_queue *q, struct inet_frags *f); void inet_frag_destroy(struct inet_frag_queue *q, struct inet_frags *f); struct inet_frag_queue *inet_frag_find(struct netns_frags *nf, struct inet_frags *f, void *key, unsigned int hash); void inet_frag_maybe_warn_overflow(struct inet_frag_queue *q, const char *prefix); static inline void inet_frag_put(struct inet_frag_queue *q, struct inet_frags *f) { if (atomic_dec_and_test(&q->refcnt)) inet_frag_destroy(q, f); } static inline bool inet_frag_evicting(struct inet_frag_queue *q) { return !hlist_unhashed(&q->list_evictor); } /* Memory Tracking Functions. */ /* The default percpu_counter batch size is not big enough to scale to * fragmentation mem acct sizes. * The mem size of a 64K fragment is approx: * (44 fragments * 2944 truesize) + frag_queue struct(200) = 129736 bytes */ static unsigned int frag_percpu_counter_batch = 130000; static inline int frag_mem_limit(struct netns_frags *nf) { return percpu_counter_read(&nf->mem); } static inline void sub_frag_mem_limit(struct netns_frags *nf, int i) { __percpu_counter_add(&nf->mem, -i, frag_percpu_counter_batch); } static inline void add_frag_mem_limit(struct netns_frags *nf, int i) { __percpu_counter_add(&nf->mem, i, frag_percpu_counter_batch); } static inline unsigned int sum_frag_mem_limit(struct netns_frags *nf) { unsigned int res; local_bh_disable(); res = percpu_counter_sum_positive(&nf->mem); local_bh_enable(); return res; } /* RFC 3168 support : * We want to check ECN values of all fragments, do detect invalid combinations. * In ipq->ecn, we store the OR value of each ip4_frag_ecn() fragment value. */ #define IPFRAG_ECN_NOT_ECT 0x01 /* one frag had ECN_NOT_ECT */ #define IPFRAG_ECN_ECT_1 0x02 /* one frag had ECN_ECT_1 */ #define IPFRAG_ECN_ECT_0 0x04 /* one frag had ECN_ECT_0 */ #define IPFRAG_ECN_CE 0x08 /* one frag had ECN_CE */ extern const u8 ip_frag_ecn_table[16]; #endif