1 #ifndef __NET_FRAG_H__ 2 #define __NET_FRAG_H__ 3 4 #include <linux/percpu_counter.h> 5 6 struct netns_frags { 7 /* The percpu_counter "mem" need to be cacheline aligned. 8 * mem.count must not share cacheline with other writers 9 */ 10 struct percpu_counter mem ____cacheline_aligned_in_smp; 11 12 /* sysctls */ 13 int timeout; 14 int high_thresh; 15 int low_thresh; 16 }; 17 18 /** 19 * fragment queue flags 20 * 21 * @INET_FRAG_FIRST_IN: first fragment has arrived 22 * @INET_FRAG_LAST_IN: final fragment has arrived 23 * @INET_FRAG_COMPLETE: frag queue has been processed and is due for destruction 24 */ 25 enum { 26 INET_FRAG_FIRST_IN = BIT(0), 27 INET_FRAG_LAST_IN = BIT(1), 28 INET_FRAG_COMPLETE = BIT(2), 29 }; 30 31 /** 32 * struct inet_frag_queue - fragment queue 33 * 34 * @lock: spinlock protecting the queue 35 * @timer: queue expiration timer 36 * @list: hash bucket list 37 * @refcnt: reference count of the queue 38 * @fragments: received fragments head 39 * @fragments_tail: received fragments tail 40 * @stamp: timestamp of the last received fragment 41 * @len: total length of the original datagram 42 * @meat: length of received fragments so far 43 * @flags: fragment queue flags 44 * @max_size: maximum received fragment size 45 * @net: namespace that this frag belongs to 46 * @list_evictor: list of queues to forcefully evict (e.g. due to low memory) 47 */ 48 struct inet_frag_queue { 49 spinlock_t lock; 50 struct timer_list timer; 51 struct hlist_node list; 52 atomic_t refcnt; 53 struct sk_buff *fragments; 54 struct sk_buff *fragments_tail; 55 ktime_t stamp; 56 int len; 57 int meat; 58 __u8 flags; 59 u16 max_size; 60 struct netns_frags *net; 61 struct hlist_node list_evictor; 62 }; 63 64 #define INETFRAGS_HASHSZ 1024 65 66 /* averaged: 67 * max_depth = default ipfrag_high_thresh / INETFRAGS_HASHSZ / 68 * rounded up (SKB_TRUELEN(0) + sizeof(struct ipq or 69 * struct frag_queue)) 70 */ 71 #define INETFRAGS_MAXDEPTH 128 72 73 struct inet_frag_bucket { 74 struct hlist_head chain; 75 spinlock_t chain_lock; 76 }; 77 78 struct inet_frags { 79 struct inet_frag_bucket hash[INETFRAGS_HASHSZ]; 80 81 struct work_struct frags_work; 82 unsigned int next_bucket; 83 unsigned long last_rebuild_jiffies; 84 bool rebuild; 85 86 /* The first call to hashfn is responsible to initialize 87 * rnd. This is best done with net_get_random_once. 88 * 89 * rnd_seqlock is used to let hash insertion detect 90 * when it needs to re-lookup the hash chain to use. 91 */ 92 u32 rnd; 93 seqlock_t rnd_seqlock; 94 int qsize; 95 96 unsigned int (*hashfn)(const struct inet_frag_queue *); 97 bool (*match)(const struct inet_frag_queue *q, 98 const void *arg); 99 void (*constructor)(struct inet_frag_queue *q, 100 const void *arg); 101 void (*destructor)(struct inet_frag_queue *); 102 void (*frag_expire)(unsigned long data); 103 struct kmem_cache *frags_cachep; 104 const char *frags_cache_name; 105 }; 106 107 int inet_frags_init(struct inet_frags *); 108 void inet_frags_fini(struct inet_frags *); 109 110 static inline int inet_frags_init_net(struct netns_frags *nf) 111 { 112 return percpu_counter_init(&nf->mem, 0, GFP_KERNEL); 113 } 114 static inline void inet_frags_uninit_net(struct netns_frags *nf) 115 { 116 percpu_counter_destroy(&nf->mem); 117 } 118 119 void inet_frags_exit_net(struct netns_frags *nf, struct inet_frags *f); 120 121 void inet_frag_kill(struct inet_frag_queue *q, struct inet_frags *f); 122 void inet_frag_destroy(struct inet_frag_queue *q, struct inet_frags *f); 123 struct inet_frag_queue *inet_frag_find(struct netns_frags *nf, 124 struct inet_frags *f, void *key, unsigned int hash); 125 126 void inet_frag_maybe_warn_overflow(struct inet_frag_queue *q, 127 const char *prefix); 128 129 static inline void inet_frag_put(struct inet_frag_queue *q, struct inet_frags *f) 130 { 131 if (atomic_dec_and_test(&q->refcnt)) 132 inet_frag_destroy(q, f); 133 } 134 135 static inline bool inet_frag_evicting(struct inet_frag_queue *q) 136 { 137 return !hlist_unhashed(&q->list_evictor); 138 } 139 140 /* Memory Tracking Functions. */ 141 142 /* The default percpu_counter batch size is not big enough to scale to 143 * fragmentation mem acct sizes. 144 * The mem size of a 64K fragment is approx: 145 * (44 fragments * 2944 truesize) + frag_queue struct(200) = 129736 bytes 146 */ 147 static unsigned int frag_percpu_counter_batch = 130000; 148 149 static inline int frag_mem_limit(struct netns_frags *nf) 150 { 151 return percpu_counter_read(&nf->mem); 152 } 153 154 static inline void sub_frag_mem_limit(struct netns_frags *nf, int i) 155 { 156 __percpu_counter_add(&nf->mem, -i, frag_percpu_counter_batch); 157 } 158 159 static inline void add_frag_mem_limit(struct netns_frags *nf, int i) 160 { 161 __percpu_counter_add(&nf->mem, i, frag_percpu_counter_batch); 162 } 163 164 static inline unsigned int sum_frag_mem_limit(struct netns_frags *nf) 165 { 166 unsigned int res; 167 168 local_bh_disable(); 169 res = percpu_counter_sum_positive(&nf->mem); 170 local_bh_enable(); 171 172 return res; 173 } 174 175 /* RFC 3168 support : 176 * We want to check ECN values of all fragments, do detect invalid combinations. 177 * In ipq->ecn, we store the OR value of each ip4_frag_ecn() fragment value. 178 */ 179 #define IPFRAG_ECN_NOT_ECT 0x01 /* one frag had ECN_NOT_ECT */ 180 #define IPFRAG_ECN_ECT_1 0x02 /* one frag had ECN_ECT_1 */ 181 #define IPFRAG_ECN_ECT_0 0x04 /* one frag had ECN_ECT_0 */ 182 #define IPFRAG_ECN_CE 0x08 /* one frag had ECN_CE */ 183 184 extern const u8 ip_frag_ecn_table[16]; 185 186 #endif 187