forked from Minki/linux
caaecdd3d3
We can simply remove the INET_FRAG_EVICTED flag to avoid all the flags race conditions with the evictor and use a participation test for the evictor list, when we're at that point (after inet_frag_kill) in the timer there're 2 possible cases: 1. The evictor added the entry to its evictor list while the timer was waiting for the chainlock or 2. The timer unchained the entry and the evictor won't see it In both cases we should be able to see list_evictor correctly due to the sync on the chainlock. Joint work with Florian Westphal. Tested-by: Frank Schreuder <fschreuder@transip.nl> Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com> Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: David S. Miller <davem@davemloft.net>
185 lines
5.0 KiB
C
185 lines
5.0 KiB
C
#ifndef __NET_FRAG_H__
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#define __NET_FRAG_H__
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#include <linux/percpu_counter.h>
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struct netns_frags {
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/* The percpu_counter "mem" need to be cacheline aligned.
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* mem.count must not share cacheline with other writers
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*/
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struct percpu_counter mem ____cacheline_aligned_in_smp;
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/* sysctls */
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int timeout;
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int high_thresh;
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int low_thresh;
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};
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/**
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* fragment queue flags
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*
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* @INET_FRAG_FIRST_IN: first fragment has arrived
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* @INET_FRAG_LAST_IN: final fragment has arrived
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* @INET_FRAG_COMPLETE: frag queue has been processed and is due for destruction
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*/
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enum {
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INET_FRAG_FIRST_IN = BIT(0),
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INET_FRAG_LAST_IN = BIT(1),
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INET_FRAG_COMPLETE = BIT(2),
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};
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/**
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* struct inet_frag_queue - fragment queue
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*
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* @lock: spinlock protecting the queue
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* @timer: queue expiration timer
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* @list: hash bucket list
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* @refcnt: reference count of the queue
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* @fragments: received fragments head
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* @fragments_tail: received fragments tail
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* @stamp: timestamp of the last received fragment
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* @len: total length of the original datagram
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* @meat: length of received fragments so far
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* @flags: fragment queue flags
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* @max_size: maximum received fragment size
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* @net: namespace that this frag belongs to
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* @list_evictor: list of queues to forcefully evict (e.g. due to low memory)
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*/
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struct inet_frag_queue {
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spinlock_t lock;
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struct timer_list timer;
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struct hlist_node list;
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atomic_t refcnt;
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struct sk_buff *fragments;
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struct sk_buff *fragments_tail;
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ktime_t stamp;
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int len;
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int meat;
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__u8 flags;
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u16 max_size;
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struct netns_frags *net;
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struct hlist_node list_evictor;
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};
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#define INETFRAGS_HASHSZ 1024
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/* averaged:
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* max_depth = default ipfrag_high_thresh / INETFRAGS_HASHSZ /
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* rounded up (SKB_TRUELEN(0) + sizeof(struct ipq or
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* struct frag_queue))
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*/
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#define INETFRAGS_MAXDEPTH 128
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struct inet_frag_bucket {
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struct hlist_head chain;
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spinlock_t chain_lock;
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};
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struct inet_frags {
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struct inet_frag_bucket hash[INETFRAGS_HASHSZ];
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struct work_struct frags_work;
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unsigned int next_bucket;
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unsigned long last_rebuild_jiffies;
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bool rebuild;
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/* The first call to hashfn is responsible to initialize
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* rnd. This is best done with net_get_random_once.
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*
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* rnd_seqlock is used to let hash insertion detect
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* when it needs to re-lookup the hash chain to use.
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*/
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u32 rnd;
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seqlock_t rnd_seqlock;
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int qsize;
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unsigned int (*hashfn)(const struct inet_frag_queue *);
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bool (*match)(const struct inet_frag_queue *q,
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const void *arg);
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void (*constructor)(struct inet_frag_queue *q,
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const void *arg);
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void (*destructor)(struct inet_frag_queue *);
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void (*skb_free)(struct sk_buff *);
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void (*frag_expire)(unsigned long data);
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struct kmem_cache *frags_cachep;
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const char *frags_cache_name;
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};
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int inet_frags_init(struct inet_frags *);
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void inet_frags_fini(struct inet_frags *);
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void inet_frags_init_net(struct netns_frags *nf);
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void inet_frags_exit_net(struct netns_frags *nf, struct inet_frags *f);
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void inet_frag_kill(struct inet_frag_queue *q, struct inet_frags *f);
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void inet_frag_destroy(struct inet_frag_queue *q, struct inet_frags *f);
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struct inet_frag_queue *inet_frag_find(struct netns_frags *nf,
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struct inet_frags *f, void *key, unsigned int hash);
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void inet_frag_maybe_warn_overflow(struct inet_frag_queue *q,
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const char *prefix);
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static inline void inet_frag_put(struct inet_frag_queue *q, struct inet_frags *f)
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{
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if (atomic_dec_and_test(&q->refcnt))
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inet_frag_destroy(q, f);
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}
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static inline bool inet_frag_evicting(struct inet_frag_queue *q)
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{
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return !hlist_unhashed(&q->list_evictor);
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}
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/* Memory Tracking Functions. */
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/* The default percpu_counter batch size is not big enough to scale to
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* fragmentation mem acct sizes.
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* The mem size of a 64K fragment is approx:
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* (44 fragments * 2944 truesize) + frag_queue struct(200) = 129736 bytes
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*/
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static unsigned int frag_percpu_counter_batch = 130000;
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static inline int frag_mem_limit(struct netns_frags *nf)
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{
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return percpu_counter_read(&nf->mem);
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}
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static inline void sub_frag_mem_limit(struct netns_frags *nf, int i)
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{
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__percpu_counter_add(&nf->mem, -i, frag_percpu_counter_batch);
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}
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static inline void add_frag_mem_limit(struct netns_frags *nf, int i)
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{
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__percpu_counter_add(&nf->mem, i, frag_percpu_counter_batch);
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}
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static inline void init_frag_mem_limit(struct netns_frags *nf)
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{
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percpu_counter_init(&nf->mem, 0, GFP_KERNEL);
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}
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static inline unsigned int sum_frag_mem_limit(struct netns_frags *nf)
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{
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unsigned int res;
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local_bh_disable();
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res = percpu_counter_sum_positive(&nf->mem);
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local_bh_enable();
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return res;
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}
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/* RFC 3168 support :
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* We want to check ECN values of all fragments, do detect invalid combinations.
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* In ipq->ecn, we store the OR value of each ip4_frag_ecn() fragment value.
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*/
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#define IPFRAG_ECN_NOT_ECT 0x01 /* one frag had ECN_NOT_ECT */
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#define IPFRAG_ECN_ECT_1 0x02 /* one frag had ECN_ECT_1 */
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#define IPFRAG_ECN_ECT_0 0x04 /* one frag had ECN_ECT_0 */
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#define IPFRAG_ECN_CE 0x08 /* one frag had ECN_CE */
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extern const u8 ip_frag_ecn_table[16];
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#endif
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