/* SPDX-License-Identifier: GPL-2.0 */ #ifndef __NET_FRAG_H__ #define __NET_FRAG_H__ #include <linux/rhashtable-types.h> #include <linux/completion.h> #include <linux/in6.h> #include <linux/rbtree_types.h> #include <linux/refcount.h> #include <net/dropreason-core.h> /* Per netns frag queues directory */ struct fqdir { /* sysctls */ long high_thresh; long low_thresh; int timeout; int max_dist; struct inet_frags *f; struct net *net; bool dead; struct rhashtable rhashtable ____cacheline_aligned_in_smp; /* Keep atomic mem on separate cachelines in structs that include it */ atomic_long_t mem ____cacheline_aligned_in_smp; struct work_struct destroy_work; struct llist_node free_list; }; /** * enum: 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 * @INET_FRAG_HASH_DEAD: inet_frag_kill() has not removed fq from rhashtable * @INET_FRAG_DROP: if skbs must be dropped (instead of being consumed) */ enum { INET_FRAG_FIRST_IN = BIT(0), INET_FRAG_LAST_IN = BIT(1), INET_FRAG_COMPLETE = BIT(2), INET_FRAG_HASH_DEAD = BIT(3), INET_FRAG_DROP = BIT(4), }; struct frag_v4_compare_key { __be32 saddr; __be32 daddr; u32 user; u32 vif; __be16 id; u16 protocol; }; struct frag_v6_compare_key { struct in6_addr saddr; struct in6_addr daddr; u32 user; __be32 id; u32 iif; }; /** * struct inet_frag_queue - fragment queue * * @node: rhash node * @key: keys identifying this frag. * @timer: queue expiration timer * @lock: spinlock protecting this frag * @refcnt: reference count of the queue * @rb_fragments: received fragments rb-tree root * @fragments_tail: received fragments tail * @last_run_head: the head of the last "run". see ip_fragment.c * @stamp: timestamp of the last received fragment * @len: total length of the original datagram * @meat: length of received fragments so far * @mono_delivery_time: stamp has a mono delivery time (EDT) * @flags: fragment queue flags * @max_size: maximum received fragment size * @fqdir: pointer to struct fqdir * @rcu: rcu head for freeing deferall */ struct inet_frag_queue { struct rhash_head node; union { struct frag_v4_compare_key v4; struct frag_v6_compare_key v6; } key; struct timer_list timer; spinlock_t lock; refcount_t refcnt; struct rb_root rb_fragments; struct sk_buff *fragments_tail; struct sk_buff *last_run_head; ktime_t stamp; int len; int meat; u8 mono_delivery_time; __u8 flags; u16 max_size; struct fqdir *fqdir; struct rcu_head rcu; }; struct inet_frags { unsigned int qsize; void (*constructor)(struct inet_frag_queue *q, const void *arg); void (*destructor)(struct inet_frag_queue *); void (*frag_expire)(struct timer_list *t); struct kmem_cache *frags_cachep; const char *frags_cache_name; struct rhashtable_params rhash_params; refcount_t refcnt; struct completion completion; }; int inet_frags_init(struct inet_frags *); void inet_frags_fini(struct inet_frags *); int fqdir_init(struct fqdir **fqdirp, struct inet_frags *f, struct net *net); static inline void fqdir_pre_exit(struct fqdir *fqdir) { /* Prevent creation of new frags. * Pairs with READ_ONCE() in inet_frag_find(). */ WRITE_ONCE(fqdir->high_thresh, 0); /* Pairs with READ_ONCE() in inet_frag_kill(), ip_expire() * and ip6frag_expire_frag_queue(). */ WRITE_ONCE(fqdir->dead, true); } void fqdir_exit(struct fqdir *fqdir); void inet_frag_kill(struct inet_frag_queue *q); void inet_frag_destroy(struct inet_frag_queue *q); struct inet_frag_queue *inet_frag_find(struct fqdir *fqdir, void *key); /* Free all skbs in the queue; return the sum of their truesizes. */ unsigned int inet_frag_rbtree_purge(struct rb_root *root, enum skb_drop_reason reason); static inline void inet_frag_put(struct inet_frag_queue *q) { if (refcount_dec_and_test(&q->refcnt)) inet_frag_destroy(q); } /* Memory Tracking Functions. */ static inline long frag_mem_limit(const struct fqdir *fqdir) { return atomic_long_read(&fqdir->mem); } static inline void sub_frag_mem_limit(struct fqdir *fqdir, long val) { atomic_long_sub(val, &fqdir->mem); } static inline void add_frag_mem_limit(struct fqdir *fqdir, long val) { atomic_long_add(val, &fqdir->mem); } /* 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]; /* Return values of inet_frag_queue_insert() */ #define IPFRAG_OK 0 #define IPFRAG_DUP 1 #define IPFRAG_OVERLAP 2 int inet_frag_queue_insert(struct inet_frag_queue *q, struct sk_buff *skb, int offset, int end); void *inet_frag_reasm_prepare(struct inet_frag_queue *q, struct sk_buff *skb, struct sk_buff *parent); void inet_frag_reasm_finish(struct inet_frag_queue *q, struct sk_buff *head, void *reasm_data, bool try_coalesce); struct sk_buff *inet_frag_pull_head(struct inet_frag_queue *q); #endif