Linux lhjmq-records 5.15.0-118-generic #128-Ubuntu SMP Fri Jul 5 09:28:59 UTC 2024 x86_64
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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __NET_FRAG_H__
#define __NET_FRAG_H__
#include <linux/rhashtable-types.h>
#include <linux/completion.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;
};
/**
* 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
*/
enum {
INET_FRAG_FIRST_IN = BIT(0),
INET_FRAG_LAST_IN = BIT(1),
INET_FRAG_COMPLETE = BIT(2),
INET_FRAG_HASH_DEAD = BIT(3),
};
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
* @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 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);
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
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