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 (*skb_free)(struct sk_buff *); 103 void (*frag_expire)(unsigned long data); 104 struct kmem_cache *frags_cachep; 105 const char *frags_cache_name; 106 }; 107 108 int inet_frags_init(struct inet_frags *); 109 void inet_frags_fini(struct inet_frags *); 110 111 void inet_frags_init_net(struct netns_frags *nf); 112 void inet_frags_exit_net(struct netns_frags *nf, struct inet_frags *f); 113 114 void inet_frag_kill(struct inet_frag_queue *q, struct inet_frags *f); 115 void inet_frag_destroy(struct inet_frag_queue *q, struct inet_frags *f); 116 struct inet_frag_queue *inet_frag_find(struct netns_frags *nf, 117 struct inet_frags *f, void *key, unsigned int hash); 118 119 void inet_frag_maybe_warn_overflow(struct inet_frag_queue *q, 120 const char *prefix); 121 122 static inline void inet_frag_put(struct inet_frag_queue *q, struct inet_frags *f) 123 { 124 if (atomic_dec_and_test(&q->refcnt)) 125 inet_frag_destroy(q, f); 126 } 127 128 static inline bool inet_frag_evicting(struct inet_frag_queue *q) 129 { 130 return !hlist_unhashed(&q->list_evictor); 131 } 132 133 /* Memory Tracking Functions. */ 134 135 /* The default percpu_counter batch size is not big enough to scale to 136 * fragmentation mem acct sizes. 137 * The mem size of a 64K fragment is approx: 138 * (44 fragments * 2944 truesize) + frag_queue struct(200) = 129736 bytes 139 */ 140 static unsigned int frag_percpu_counter_batch = 130000; 141 142 static inline int frag_mem_limit(struct netns_frags *nf) 143 { 144 return percpu_counter_read(&nf->mem); 145 } 146 147 static inline void sub_frag_mem_limit(struct netns_frags *nf, int i) 148 { 149 __percpu_counter_add(&nf->mem, -i, frag_percpu_counter_batch); 150 } 151 152 static inline void add_frag_mem_limit(struct netns_frags *nf, int i) 153 { 154 __percpu_counter_add(&nf->mem, i, frag_percpu_counter_batch); 155 } 156 157 static inline void init_frag_mem_limit(struct netns_frags *nf) 158 { 159 percpu_counter_init(&nf->mem, 0, GFP_KERNEL); 160 } 161 162 static inline unsigned int sum_frag_mem_limit(struct netns_frags *nf) 163 { 164 unsigned int res; 165 166 local_bh_disable(); 167 res = percpu_counter_sum_positive(&nf->mem); 168 local_bh_enable(); 169 170 return res; 171 } 172 173 /* RFC 3168 support : 174 * We want to check ECN values of all fragments, do detect invalid combinations. 175 * In ipq->ecn, we store the OR value of each ip4_frag_ecn() fragment value. 176 */ 177 #define IPFRAG_ECN_NOT_ECT 0x01 /* one frag had ECN_NOT_ECT */ 178 #define IPFRAG_ECN_ECT_1 0x02 /* one frag had ECN_ECT_1 */ 179 #define IPFRAG_ECN_ECT_0 0x04 /* one frag had ECN_ECT_0 */ 180 #define IPFRAG_ECN_CE 0x08 /* one frag had ECN_CE */ 181 182 extern const u8 ip_frag_ecn_table[16]; 183 184 #endif 185