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 unsigned long pmtu_expires; 40 u32 pmtu_orig; 41 u32 pmtu_learned; 42 struct inetpeer_addr_base redirect_learned; 43 /* 44 * Once inet_peer is queued for deletion (refcnt == -1), following fields 45 * are not available: rid, ip_id_count, tcp_ts, tcp_ts_stamp 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 __u32 tcp_ts; 53 __u32 tcp_ts_stamp; 54 }; 55 struct rcu_head rcu; 56 struct inet_peer *gc_next; 57 }; 58 59 /* following fields might be frequently dirtied */ 60 __u32 dtime; /* the time of last use of not referenced entries */ 61 atomic_t refcnt; 62 }; 63 64 void inet_initpeers(void) __init; 65 66 #define INETPEER_METRICS_NEW (~(u32) 0) 67 68 static inline bool inet_metrics_new(const struct inet_peer *p) 69 { 70 return p->metrics[RTAX_LOCK-1] == INETPEER_METRICS_NEW; 71 } 72 73 /* can be called with or without local BH being disabled */ 74 struct inet_peer *inet_getpeer(const struct inetpeer_addr *daddr, int create); 75 76 static inline struct inet_peer *inet_getpeer_v4(__be32 v4daddr, int create) 77 { 78 struct inetpeer_addr daddr; 79 80 daddr.addr.a4 = v4daddr; 81 daddr.family = AF_INET; 82 return inet_getpeer(&daddr, create); 83 } 84 85 static inline struct inet_peer *inet_getpeer_v6(const struct in6_addr *v6daddr, int create) 86 { 87 struct inetpeer_addr daddr; 88 89 ipv6_addr_copy((struct in6_addr *)daddr.addr.a6, v6daddr); 90 daddr.family = AF_INET6; 91 return inet_getpeer(&daddr, create); 92 } 93 94 /* can be called from BH context or outside */ 95 extern void inet_putpeer(struct inet_peer *p); 96 extern bool inet_peer_xrlim_allow(struct inet_peer *peer, int timeout); 97 98 /* 99 * temporary check to make sure we dont access rid, ip_id_count, tcp_ts, 100 * tcp_ts_stamp if no refcount is taken on inet_peer 101 */ 102 static inline void inet_peer_refcheck(const struct inet_peer *p) 103 { 104 WARN_ON_ONCE(atomic_read(&p->refcnt) <= 0); 105 } 106 107 108 /* can be called with or without local BH being disabled */ 109 static inline int inet_getid(struct inet_peer *p, int more) 110 { 111 int old, new; 112 more++; 113 inet_peer_refcheck(p); 114 do { 115 old = atomic_read(&p->ip_id_count); 116 new = old + more; 117 if (!new) 118 new = 1; 119 } while (atomic_cmpxchg(&p->ip_id_count, old, new) != old); 120 return new; 121 } 122 123 #endif /* _NET_INETPEER_H */ 124