| 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 field |
| 45 | * is not available: rid |
| 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 | }; |
| 52 | struct rcu_head rcu; |
| 53 | struct inet_peer *gc_next; |
| 54 | }; |
| 55 | |
| 56 | /* following fields might be frequently dirtied */ |
| 57 | __u32 dtime; /* the time of last use of not referenced entries */ |
| 58 | atomic_t refcnt; |
| 59 | }; |
| 60 | |
| 61 | struct inet_peer_base { |
| 62 | struct inet_peer __rcu *root; |
| 63 | seqlock_t lock; |
| 64 | int total; |
| 65 | }; |
| 66 | |
| 67 | #define INETPEER_BASE_BIT 0x1UL |
| 68 | |
| 69 | static inline struct inet_peer *inetpeer_ptr(unsigned long val) |
| 70 | { |
| 71 | BUG_ON(val & INETPEER_BASE_BIT); |
| 72 | return (struct inet_peer *) val; |
| 73 | } |
| 74 | |
| 75 | static inline struct inet_peer_base *inetpeer_base_ptr(unsigned long val) |
| 76 | { |
| 77 | if (!(val & INETPEER_BASE_BIT)) |
| 78 | return NULL; |
| 79 | val &= ~INETPEER_BASE_BIT; |
| 80 | return (struct inet_peer_base *) val; |
| 81 | } |
| 82 | |
| 83 | static inline bool inetpeer_ptr_is_peer(unsigned long val) |
| 84 | { |
| 85 | return !(val & INETPEER_BASE_BIT); |
| 86 | } |
| 87 | |
| 88 | static inline void __inetpeer_ptr_set_peer(unsigned long *val, struct inet_peer *peer) |
| 89 | { |
| 90 | /* This implicitly clears INETPEER_BASE_BIT */ |
| 91 | *val = (unsigned long) peer; |
| 92 | } |
| 93 | |
| 94 | static inline bool inetpeer_ptr_set_peer(unsigned long *ptr, struct inet_peer *peer) |
| 95 | { |
| 96 | unsigned long val = (unsigned long) peer; |
| 97 | unsigned long orig = *ptr; |
| 98 | |
| 99 | if (!(orig & INETPEER_BASE_BIT) || |
| 100 | cmpxchg(ptr, orig, val) != orig) |
| 101 | return false; |
| 102 | return true; |
| 103 | } |
| 104 | |
| 105 | static inline void inetpeer_init_ptr(unsigned long *ptr, struct inet_peer_base *base) |
| 106 | { |
| 107 | *ptr = (unsigned long) base | INETPEER_BASE_BIT; |
| 108 | } |
| 109 | |
| 110 | static inline void inetpeer_transfer_peer(unsigned long *to, unsigned long *from) |
| 111 | { |
| 112 | unsigned long val = *from; |
| 113 | |
| 114 | *to = val; |
| 115 | if (inetpeer_ptr_is_peer(val)) { |
| 116 | struct inet_peer *peer = inetpeer_ptr(val); |
| 117 | atomic_inc(&peer->refcnt); |
| 118 | } |
| 119 | } |
| 120 | |
| 121 | void inet_peer_base_init(struct inet_peer_base *); |
| 122 | |
| 123 | void inet_initpeers(void) __init; |
| 124 | |
| 125 | #define INETPEER_METRICS_NEW (~(u32) 0) |
| 126 | |
| 127 | static inline bool inet_metrics_new(const struct inet_peer *p) |
| 128 | { |
| 129 | return p->metrics[RTAX_LOCK-1] == INETPEER_METRICS_NEW; |
| 130 | } |
| 131 | |
| 132 | /* can be called with or without local BH being disabled */ |
| 133 | struct inet_peer *inet_getpeer(struct inet_peer_base *base, |
| 134 | const struct inetpeer_addr *daddr, |
| 135 | int create); |
| 136 | |
| 137 | static inline struct inet_peer *inet_getpeer_v4(struct inet_peer_base *base, |
| 138 | __be32 v4daddr, |
| 139 | int create) |
| 140 | { |
| 141 | struct inetpeer_addr daddr; |
| 142 | |
| 143 | daddr.addr.a4 = v4daddr; |
| 144 | daddr.family = AF_INET; |
| 145 | return inet_getpeer(base, &daddr, create); |
| 146 | } |
| 147 | |
| 148 | static inline struct inet_peer *inet_getpeer_v6(struct inet_peer_base *base, |
| 149 | const struct in6_addr *v6daddr, |
| 150 | int create) |
| 151 | { |
| 152 | struct inetpeer_addr daddr; |
| 153 | |
| 154 | *(struct in6_addr *)daddr.addr.a6 = *v6daddr; |
| 155 | daddr.family = AF_INET6; |
| 156 | return inet_getpeer(base, &daddr, create); |
| 157 | } |
| 158 | |
| 159 | /* can be called from BH context or outside */ |
| 160 | void inet_putpeer(struct inet_peer *p); |
| 161 | bool inet_peer_xrlim_allow(struct inet_peer *peer, int timeout); |
| 162 | |
| 163 | void inetpeer_invalidate_tree(struct inet_peer_base *); |
| 164 | |
| 165 | /* |
| 166 | * temporary check to make sure we dont access rid, tcp_ts, |
| 167 | * tcp_ts_stamp if no refcount is taken on inet_peer |
| 168 | */ |
| 169 | static inline void inet_peer_refcheck(const struct inet_peer *p) |
| 170 | { |
| 171 | WARN_ON_ONCE(atomic_read(&p->refcnt) <= 0); |
| 172 | } |
| 173 | #endif /* _NET_INETPEER_H */ |