108 lines
3.3 KiB
C
Executable File
108 lines
3.3 KiB
C
Executable File
/*
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* Copyright (c) 1991 by Sun Microsystems, Inc.
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*/
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#ifndef _SYS_BUFMOD_H
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#define _SYS_BUFMOD_H
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#pragma ident "@(#)bufmod.h 1.6 93/09/08 SMI"
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#ifdef __cplusplus
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extern "C" {
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#endif
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/*
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* Definitions for the STREAMS Buffering module.
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*
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* The module gathers incoming (read-side) messages together into
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* "chunks" and passes completed chunks up to the next module in
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* line. The gathering process is controlled by two ioctl-settable
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* parameters:
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*
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* timeout The maximum delay after passing the previous chunk
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* upward before passing the current one up, even if the
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* chunk isn't full. If the timeout value passed in is
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* a null pointer, the timeout is infinite (as in the
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* select system call); this is the default.
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* chunksize The maximum size of a chunk of accumulated messages,
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* unless a single message exceeds the chunksize, in
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* which case it's passed up in a chunk containing only
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* that message. Note that a given message's size includes
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* the length of any leading M_PROTO blocks it may have.
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*
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* There is one important side-effect: setting the timeout to zero
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* (polling) will force the chunksize to zero, regardless of its
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* previous setting.
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*/
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/*
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* Ioctls.
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*/
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#define SBIOC ('B' << 8)
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#define SBIOCSTIME (SBIOC|1) /* set timeout info */
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#define SBIOCGTIME (SBIOC|2) /* get timeout info */
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#define SBIOCCTIME (SBIOC|3) /* clear timeout */
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#define SBIOCSCHUNK (SBIOC|4) /* set chunksize */
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#define SBIOCGCHUNK (SBIOC|5) /* get chunksize */
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#define SBIOCSSNAP (SBIOC|6) /* set snapshot length */
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#define SBIOCGSNAP (SBIOC|7) /* get snapshot length */
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#define SBIOCSFLAGS (SBIOC|8) /* set buffering modes */
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#define SBIOCGFLAGS (SBIOC|9) /* get buffering modes */
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/*
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* Default chunk size.
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*/
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#define SB_DFLT_CHUNK 8192 /* arbitrary */
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/*
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* buffering flags
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*/
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#define SB_SEND_ON_WRITE 1 /* return buffered read data on write */
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#define SB_NO_HEADER 2 /* don't add header structure to data */
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#define SB_NO_PROTO_CVT 4 /* don't convert proto to data */
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#define SB_DEFER_CHUNK 8 /* fast response time buffering */
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#define SB_NO_DROPS 16 /* Don't drop messages */
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/*
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* buffering state
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*/
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#define SB_FRCVD 1 /* first message in time window received */
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/*
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* When adding a given message to an accumulating chunk, the module
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* first converts any leading M_PROTO data block to M_DATA.
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* It then constructs an sb_hdr (defined below), prepends it to
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* the message, and pads the result out to force its length to a
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* multiple of a machine-dependent alignment size guaranteed to be
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* at least sizeof (u_long). It then adds the padded message to the
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* chunk.
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*
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* sb_origlen is the original length of the message after the M_PROTO => M_DATA
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* conversion, but before truncating or adding the header.
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*
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* sb_msglen is the length of the message after truncation, but before
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* adding the header.
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*
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* sb_totlen is the length of the message after truncation, and including
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* both the header itself and the trailing padding bytes.
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*
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* sb_drops is the cumulative number of messages dropped by the module
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* due to stream read-side flow control or resource exhaustion.
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*
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* sb_timestamp is the packet arrival time expressed as a 'struct timeval'.
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*/
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struct sb_hdr {
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u_int sbh_origlen;
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u_int sbh_msglen;
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u_int sbh_totlen;
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u_int sbh_drops;
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struct timeval sbh_timestamp;
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};
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#ifdef __cplusplus
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}
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#endif
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#endif /* _SYS_BUFMOD_H */
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