xref: /netbsd-src/external/bsd/ntp/dist/include/recvbuff.h (revision 50c1bace9687b37ab860a3ac85b157d33cb3f3d6)
1 /*	$NetBSD: recvbuff.h,v 1.8 2022/10/09 21:41:03 christos Exp $	*/
2 
3 #ifndef RECVBUFF_H
4 #define RECVBUFF_H
5 
6 #include "ntp.h"
7 #include "ntp_net.h"
8 #include "ntp_lists.h"
9 
10 #include <isc/result.h>
11 
12 /*
13  * recvbuf memory management
14  */
15 #define RECV_INIT	64	/* 64 buffers initially */
16 #define RECV_LOWAT	3	/* when we're down to three buffers get more */
17 #define RECV_INC	32	/* [power of 2] get 32 more at a time */
18 #define RECV_BATCH	128	/* [power of 2] max increment in one sweep */
19 #define RECV_TOOMANY	4096	/* this should suffice, really. TODO: tos option? */
20 
21 /* If we have clocks, keep an iron reserve of receive buffers for
22  * clocks only.
23  */
24 #if defined(REFCLOCK)
25 # if !defined(RECV_CLOCK) || RECV_CLOCK == 0
26 #  undef RECV_CLOCK
27 #  define RECV_CLOCK	16
28 # endif
29 #else
30 # if defined(RECV_CLOCK)
31 #  undef RECV_CLOCK
32 # endif
33 # define RECV_CLOCK 0
34 #endif
35 
36 #if defined HAVE_IO_COMPLETION_PORT
37 # include "ntp_iocompletionport.h"
38 # include "ntp_timer.h"
39 
40 # define RECV_BLOCK_IO()	EnterCriticalSection(&RecvCritSection)
41 # define RECV_UNBLOCK_IO()	LeaveCriticalSection(&RecvCritSection)
42 
43 /*  Return the event which is set when items are added to the full list
44  */
45 extern HANDLE	get_recv_buff_event(void);
46 #else
47 # define RECV_BLOCK_IO()
48 # define RECV_UNBLOCK_IO()
49 #endif
50 
51 
52 /*
53  * Format of a recvbuf.  These are used by the asynchronous receive
54  * routine to store incoming packets and related information.
55  */
56 
57 /*
58  *  the maximum length NTP packet contains the NTP header, one Autokey
59  *  request, one Autokey response and the MAC. Assuming certificates don't
60  *  get too big, the maximum packet length is set arbitrarily at 1200.
61  *  (was 1000, but that bumps on 2048 RSA keys)
62  */
63 #define	RX_BUFF_SIZE	1200		/* hail Mary */
64 
65 
66 typedef struct recvbuf recvbuf_t;
67 
68 struct recvbuf {
69 	recvbuf_t *	link;	/* next in list */
70 	union {
71 		sockaddr_u	X_recv_srcadr;
72 		caddr_t		X_recv_srcclock;
73 		struct peer *	X_recv_peer;
74 	} X_from_where;
75 #define recv_srcadr		X_from_where.X_recv_srcadr
76 #define	recv_srcclock		X_from_where.X_recv_srcclock
77 #define recv_peer		X_from_where.X_recv_peer
78 #ifndef HAVE_IO_COMPLETION_PORT
79 	sockaddr_u	srcadr;		/* where packet came from */
80 #else
81 	int		recv_srcadr_len;/* filled in on completion */
82 #endif
83 	endpt *		dstadr;		/* address pkt arrived on */
84 	SOCKET		fd;		/* fd on which it was received */
85 	int		msg_flags;	/* Flags received about the packet */
86 	l_fp		recv_time;	/* time of arrival */
87 	void		(*receiver)(struct recvbuf *); /* callback */
88 	int		recv_length;	/* number of octets received */
89 	union {
90 		struct pkt	X_recv_pkt;
91 		u_char		X_recv_buffer[RX_BUFF_SIZE];
92 	} recv_space;
93 #define	recv_pkt		recv_space.X_recv_pkt
94 #define	recv_buffer		recv_space.X_recv_buffer
95 	int used;		/* reference count */
96 };
97 
98 extern	void	init_recvbuff(int);
99 
100 /* freerecvbuf - make a single recvbuf available for reuse
101  */
102 extern	void	freerecvbuf(struct recvbuf *);
103 
104 /*  Get a free buffer (typically used so an async
105  *  read can directly place data into the buffer
106  *
107  *  The buffer is removed from the free list. Make sure
108  *  you put it back with freerecvbuf() or
109  */
110 
111 /* signal safe - no malloc, returns NULL when no bufs */
112 extern	struct recvbuf *get_free_recv_buffer(int /*BOOL*/ urgent);
113 /* signal unsafe - may malloc, returns NULL when no bufs */
114 extern	struct recvbuf *get_free_recv_buffer_alloc(int /*BOOL*/ urgent);
115 
116 /*   Add a buffer to the full list
117  */
118 extern	void	add_full_recv_buffer(struct recvbuf *);
119 
120 /* number of recvbufs on freelist */
121 extern u_long free_recvbuffs(void);
122 extern u_long full_recvbuffs(void);
123 extern u_long total_recvbuffs(void);
124 extern u_long lowater_additions(void);
125 
126 /*  Returns the next buffer in the full list.
127  *
128  */
129 extern	struct recvbuf *get_full_recv_buffer(void);
130 
131 /*
132  * purge_recv_buffers_for_fd() - purges any previously-received input
133  *				 from a given file descriptor.
134  */
135 extern	void purge_recv_buffers_for_fd(int);
136 
137 /*
138  * Checks to see if there are buffers to process
139  */
140 extern isc_boolean_t has_full_recv_buffer(void);
141 
142 #endif	/* RECVBUFF_H */
143