2 * Copyright (c) 2004-2006 The DragonFly Project. All rights reserved.
4 * This code is derived from software contributed to The DragonFly Project
5 * by Matthew Dillon <dillon@backplane.com>
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in
15 * the documentation and/or other materials provided with the
17 * 3. Neither the name of The DragonFly Project nor the names of its
18 * contributors may be used to endorse or promote products derived
19 * from this software without specific, prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * $DragonFly: src/sys/sys/syslink_msg.h,v 1.6 2007/04/03 20:21:19 dillon Exp $
37 * The syslink infrastructure implements an optimized RPC mechanism across a
38 * communications link. Endpoints, defined by a sysid, are typically
39 * associated with system structures but do not have to be.
41 * This header file is primarily responsible for the formatting of message
42 * traffic over a syslink.
45 #ifndef _SYS_SYSLINK_MSG_H_
46 #define _SYS_SYSLINK_MSG_H_
49 #include <sys/types.h>
51 #ifndef _MACHINE_ATOMIC_H_
52 #include <machine/atomic.h>
55 typedef u_int32_t sl_msgid_t; /* transaction sequencing */
56 typedef u_int16_t sl_cmd_t; /* command or error */
57 typedef sl_cmd_t sl_error_t;
58 typedef u_int16_t sl_itemid_t; /* item id */
59 typedef u_int16_t sl_reclen_t; /* item length */
61 #define SL_ALIGN 8 /* 8-byte alignment */
62 #define SL_ALIGNMASK (SL_ALIGN - 1)
65 * Stream or FIFO based messaging structures.
67 * The reclen is the actual record length in bytes prior to alignment.
68 * The reclen must be aligned to obtain the actual size of a syslink_msg
69 * or syslink_item structure. Note that the reclen includes structural
70 * headers (i.e. it does not represent just the data payload, it represents
71 * the entire structure).
73 * Sessions are identified with a session id. The session id is a rendezvous
74 * id that associates physical and logical routing information with a single
75 * sysid, allowing us to both avoid storing the source and target logical id
76 * in the syslink message AND ALSO providing a unique session id and validator
77 * which manages the abstracted connection between two entities. Otherwise
78 * the syslink message would become bloated with five sysid fields instead
79 * of the three we have now.
81 * Link layer communications is accomplished by specifying a target physical
84 * The target physical address is deconstructed as the message hops across
85 * the mesh. All 0's, or all 0's remaining indicates a link layer message
86 * to be processed by the syslink route node itself. All 1's indicates
87 * a broadcast message. Broadcast messages also require special attention.
88 * Sending a message to a target address of 0 basically sends it to the
89 * directly connected syslink node.
91 * The source physical address normally starts out as 0 and is constructed
92 * as the message hops across the mesh. The target can use the constructed
93 * source address to respond to the originator of the message (as it must
94 * if it has not knowledge about the session id). A target with knowledge
95 * of the session id has the option of forging its own return both.
99 * Raw protocol structures
102 sl_cmd_t sm_cmd; /* protocol command code */
103 sl_reclen_t sm_bytes; /* unaligned size of message */
104 sl_msgid_t sm_msgid; /* message transaction control */
105 /* minimum syslink_msg size is 8 bytes (special PAD) */
106 sysid_t sm_sessid; /* session id */
107 sysid_t sm_srcphysid; /* originating physical id */
108 sysid_t sm_dstphysid; /* target physical id */
111 #define SL_MIN_MESSAGE_SIZE offsetof(struct syslink_msg, sm_sessid)
113 #define SL_MSGID_REPLY 0x80000000 /* command vs reply */
114 #define SL_MSGID_ORIG 0x40000000 /* originator transaction */
115 /* (else target transaction) */
116 #define SL_MSGID_BEG 0x20000000 /* first msg in transaction */
117 #define SL_MSGID_END 0x10000000 /* last msg in transaction */
118 #define SL_MSGID_STRUCTURED 0x08000000 /* contains structured data */
119 #define SL_MSGID_COMPLETE 0x04000000 /* msg not under construction */
120 #define SL_MSGID_TRANS_MASK 0x00FFFF00 /* transaction id */
121 #define SL_MSGID_SEQ_MASK 0x000000FF /* sequence no within trans */
123 #define SLMSG_ALIGN(bytes) (((bytes) + 7) & ~7)
126 * Syslink message commands (16 bits, bit 15 must be 0)
128 * Commands 0x0000-0x001F are reserved for the universal link layer, but
129 * except for 0x0000 (which is a PAD message), must still be properly
132 * Commands 0x0020-0x002F are reserved for the universal protocol
133 * identification layer.
135 * Commands 0x0100-0x7FFF are protocol commands.
137 * The command field is the error return field with bit 15 set in the
140 #define SL_CMD_PAD 0x0000
141 #define SL_CMD_LINK_MESH 0x0001 /* mesh construction */
142 #define SL_CMD_LINK_REG 0x0002 /* register logical id */
143 #define SL_CMD_LINK_DEREG 0x0003 /* unregister logical id */
144 #define SL_CMD_LINK_ID 0x0004 /* link level identification */
146 #define SL_CMD_PROT_ID 0x0010 /* protocol & device ident */
149 * Message elements for structured messages. If SL_MSGID_STRUCTURED is
150 * set the syslink message contains zero or more syslink_elm structures
151 * laid side by side. Each syslink_elm structure may or may not be
152 * structured (i.e. recursive).
154 * Most of the same SL_MSGID_* bits apply. The first structured element
155 * will have SL_MSGID_BEG set, the last will have SL_MSGID_END set (if
156 * there is only one element, both bits will be set in that element). If
157 * the payload is structured, SL_MSGID_STRUCTURED will be set.
159 * syslink_elm's may use the TRANS and SEQ bits in the msgid for other
160 * purposes. A syslink_elm is considered to be a PAD if se_cmd == 0.
164 sl_reclen_t se_bytes;
166 /* extended by data */
169 typedef struct syslink_msg *syslink_msg_t;
170 typedef struct syslink_elm *syslink_elm_t;