1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3  * INET		An implementation of the TCP/IP protocol suite for the LINUX
4  *		operating system.  INET is implemented using the  BSD Socket
5  *		interface as the means of communication with the user level.
6  *
7  *		Definitions for a generic INET TIMEWAIT sock
8  *
9  *		From code originally in net/tcp.h
10  */
11 #ifndef _INET_TIMEWAIT_SOCK_
12 #define _INET_TIMEWAIT_SOCK_
13 
14 #include <linux/list.h>
15 #include <linux/timer.h>
16 #include <linux/types.h>
17 #include <linux/workqueue.h>
18 
19 #include <net/inet_sock.h>
20 #include <net/sock.h>
21 #include <net/tcp_states.h>
22 #include <net/timewait_sock.h>
23 
24 #include <linux/atomic.h>
25 
26 struct inet_bind_bucket;
27 
28 /*
29  * This is a TIME_WAIT sock. It works around the memory consumption
30  * problems of sockets in such a state on heavily loaded servers, but
31  * without violating the protocol specification.
32  */
33 struct inet_timewait_sock {
34 	/*
35 	 * Now struct sock also uses sock_common, so please just
36 	 * don't add nothing before this first member (__tw_common) --acme
37 	 */
38 	struct sock_common	__tw_common;
39 #define tw_family		__tw_common.skc_family
40 #define tw_state		__tw_common.skc_state
41 #define tw_reuse		__tw_common.skc_reuse
42 #define tw_reuseport		__tw_common.skc_reuseport
43 #define tw_ipv6only		__tw_common.skc_ipv6only
44 #define tw_bound_dev_if		__tw_common.skc_bound_dev_if
45 #define tw_node			__tw_common.skc_nulls_node
46 #define tw_bind_node		__tw_common.skc_bind_node
47 #define tw_refcnt		__tw_common.skc_refcnt
48 #define tw_hash			__tw_common.skc_hash
49 #define tw_prot			__tw_common.skc_prot
50 #define tw_net			__tw_common.skc_net
51 #define tw_daddr        	__tw_common.skc_daddr
52 #define tw_v6_daddr		__tw_common.skc_v6_daddr
53 #define tw_rcv_saddr    	__tw_common.skc_rcv_saddr
54 #define tw_v6_rcv_saddr    	__tw_common.skc_v6_rcv_saddr
55 #define tw_dport		__tw_common.skc_dport
56 #define tw_num			__tw_common.skc_num
57 #define tw_cookie		__tw_common.skc_cookie
58 #define tw_dr			__tw_common.skc_tw_dr
59 
60 	__u32			tw_mark;
61 	volatile unsigned char	tw_substate;
62 	unsigned char		tw_rcv_wscale;
63 
64 	/* Socket demultiplex comparisons on incoming packets. */
65 	/* these three are in inet_sock */
66 	__be16			tw_sport;
67 	/* And these are ours. */
68 	unsigned int		tw_kill		: 1,
69 				tw_transparent  : 1,
70 				tw_flowlabel	: 20,
71 				tw_pad		: 2,	/* 2 bits hole */
72 				tw_tos		: 8;
73 	u32			tw_txhash;
74 	struct timer_list	tw_timer;
75 	struct inet_bind_bucket	*tw_tb;
76 };
77 #define tw_tclass tw_tos
78 
79 static inline struct inet_timewait_sock *inet_twsk(const struct sock *sk)
80 {
81 	return (struct inet_timewait_sock *)sk;
82 }
83 
84 void inet_twsk_free(struct inet_timewait_sock *tw);
85 void inet_twsk_put(struct inet_timewait_sock *tw);
86 
87 void inet_twsk_bind_unhash(struct inet_timewait_sock *tw,
88 			   struct inet_hashinfo *hashinfo);
89 
90 struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk,
91 					   struct inet_timewait_death_row *dr,
92 					   const int state);
93 
94 void inet_twsk_hashdance(struct inet_timewait_sock *tw, struct sock *sk,
95 			 struct inet_hashinfo *hashinfo);
96 
97 void __inet_twsk_schedule(struct inet_timewait_sock *tw, int timeo,
98 			  bool rearm);
99 
100 static inline void inet_twsk_schedule(struct inet_timewait_sock *tw, int timeo)
101 {
102 	__inet_twsk_schedule(tw, timeo, false);
103 }
104 
105 static inline void inet_twsk_reschedule(struct inet_timewait_sock *tw, int timeo)
106 {
107 	__inet_twsk_schedule(tw, timeo, true);
108 }
109 
110 void inet_twsk_deschedule_put(struct inet_timewait_sock *tw);
111 
112 void inet_twsk_purge(struct inet_hashinfo *hashinfo, int family);
113 
114 static inline
115 struct net *twsk_net(const struct inet_timewait_sock *twsk)
116 {
117 	return read_pnet(&twsk->tw_net);
118 }
119 
120 static inline
121 void twsk_net_set(struct inet_timewait_sock *twsk, struct net *net)
122 {
123 	write_pnet(&twsk->tw_net, net);
124 }
125 #endif	/* _INET_TIMEWAIT_SOCK_ */
126