1 /* 2 * INETPEER - A storage for permanent information about peers 3 * 4 * Authors: Andrey V. Savochkin <saw@msu.ru> 5 */ 6 7 #ifndef _NET_INETPEER_H 8 #define _NET_INETPEER_H 9 10 #include <linux/types.h> 11 #include <linux/init.h> 12 #include <linux/jiffies.h> 13 #include <linux/spinlock.h> 14 #include <linux/rtnetlink.h> 15 #include <net/ipv6.h> 16 #include <linux/atomic.h> 17 18 struct inetpeer_addr_base { 19 union { 20 __be32 a4; 21 __be32 a6[4]; 22 }; 23 }; 24 25 struct inetpeer_addr { 26 struct inetpeer_addr_base addr; 27 __u16 family; 28 }; 29 30 struct inet_peer { 31 /* group together avl_left,avl_right,v4daddr to speedup lookups */ 32 struct inet_peer __rcu *avl_left, *avl_right; 33 struct inetpeer_addr daddr; 34 __u32 avl_height; 35 36 u32 metrics[RTAX_MAX]; 37 u32 rate_tokens; /* rate limiting for ICMP */ 38 unsigned long rate_last; 39 union { 40 struct list_head gc_list; 41 struct rcu_head gc_rcu; 42 }; 43 /* 44 * Once inet_peer is queued for deletion (refcnt == -1), following fields 45 * are not available: rid, ip_id_count 46 * We can share memory with rcu_head to help keep inet_peer small. 47 */ 48 union { 49 struct { 50 atomic_t rid; /* Frag reception counter */ 51 atomic_t ip_id_count; /* IP ID for the next packet */ 52 }; 53 struct rcu_head rcu; 54 struct inet_peer *gc_next; 55 }; 56 57 /* following fields might be frequently dirtied */ 58 __u32 dtime; /* the time of last use of not referenced entries */ 59 atomic_t refcnt; 60 }; 61 62 struct inet_peer_base { 63 struct inet_peer __rcu *root; 64 seqlock_t lock; 65 u32 flush_seq; 66 int total; 67 }; 68 69 #define INETPEER_BASE_BIT 0x1UL 70 71 static inline struct inet_peer *inetpeer_ptr(unsigned long val) 72 { 73 BUG_ON(val & INETPEER_BASE_BIT); 74 return (struct inet_peer *) val; 75 } 76 77 static inline struct inet_peer_base *inetpeer_base_ptr(unsigned long val) 78 { 79 if (!(val & INETPEER_BASE_BIT)) 80 return NULL; 81 val &= ~INETPEER_BASE_BIT; 82 return (struct inet_peer_base *) val; 83 } 84 85 static inline bool inetpeer_ptr_is_peer(unsigned long val) 86 { 87 return !(val & INETPEER_BASE_BIT); 88 } 89 90 static inline void __inetpeer_ptr_set_peer(unsigned long *val, struct inet_peer *peer) 91 { 92 /* This implicitly clears INETPEER_BASE_BIT */ 93 *val = (unsigned long) peer; 94 } 95 96 static inline bool inetpeer_ptr_set_peer(unsigned long *ptr, struct inet_peer *peer) 97 { 98 unsigned long val = (unsigned long) peer; 99 unsigned long orig = *ptr; 100 101 if (!(orig & INETPEER_BASE_BIT) || 102 cmpxchg(ptr, orig, val) != orig) 103 return false; 104 return true; 105 } 106 107 static inline void inetpeer_init_ptr(unsigned long *ptr, struct inet_peer_base *base) 108 { 109 *ptr = (unsigned long) base | INETPEER_BASE_BIT; 110 } 111 112 static inline void inetpeer_transfer_peer(unsigned long *to, unsigned long *from) 113 { 114 unsigned long val = *from; 115 116 *to = val; 117 if (inetpeer_ptr_is_peer(val)) { 118 struct inet_peer *peer = inetpeer_ptr(val); 119 atomic_inc(&peer->refcnt); 120 } 121 } 122 123 extern void inet_peer_base_init(struct inet_peer_base *); 124 125 void inet_initpeers(void) __init; 126 127 #define INETPEER_METRICS_NEW (~(u32) 0) 128 129 static inline bool inet_metrics_new(const struct inet_peer *p) 130 { 131 return p->metrics[RTAX_LOCK-1] == INETPEER_METRICS_NEW; 132 } 133 134 /* can be called with or without local BH being disabled */ 135 struct inet_peer *inet_getpeer(struct inet_peer_base *base, 136 const struct inetpeer_addr *daddr, 137 int create); 138 139 static inline struct inet_peer *inet_getpeer_v4(struct inet_peer_base *base, 140 __be32 v4daddr, 141 int create) 142 { 143 struct inetpeer_addr daddr; 144 145 daddr.addr.a4 = v4daddr; 146 daddr.family = AF_INET; 147 return inet_getpeer(base, &daddr, create); 148 } 149 150 static inline struct inet_peer *inet_getpeer_v6(struct inet_peer_base *base, 151 const struct in6_addr *v6daddr, 152 int create) 153 { 154 struct inetpeer_addr daddr; 155 156 *(struct in6_addr *)daddr.addr.a6 = *v6daddr; 157 daddr.family = AF_INET6; 158 return inet_getpeer(base, &daddr, create); 159 } 160 161 /* can be called from BH context or outside */ 162 extern void inet_putpeer(struct inet_peer *p); 163 extern bool inet_peer_xrlim_allow(struct inet_peer *peer, int timeout); 164 165 extern void inetpeer_invalidate_tree(struct inet_peer_base *); 166 extern void inetpeer_invalidate_family(int family); 167 168 /* 169 * temporary check to make sure we dont access rid, ip_id_count, tcp_ts, 170 * tcp_ts_stamp if no refcount is taken on inet_peer 171 */ 172 static inline void inet_peer_refcheck(const struct inet_peer *p) 173 { 174 WARN_ON_ONCE(atomic_read(&p->refcnt) <= 0); 175 } 176 177 178 /* can be called with or without local BH being disabled */ 179 static inline int inet_getid(struct inet_peer *p, int more) 180 { 181 int old, new; 182 more++; 183 inet_peer_refcheck(p); 184 do { 185 old = atomic_read(&p->ip_id_count); 186 new = old + more; 187 if (!new) 188 new = 1; 189 } while (atomic_cmpxchg(&p->ip_id_count, old, new) != old); 190 return new; 191 } 192 193 #endif /* _NET_INETPEER_H */ 194