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      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