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1.1 root 1: /*
2: * Copyright (c) 1988 Regents of the University of California.
3: * All rights reserved.
4: *
5: * Redistribution and use in source and binary forms are permitted
6: * provided that this notice is preserved and that due credit is given
7: * to the University of California at Berkeley. The name of the University
8: * may not be used to endorse or promote products derived from this
9: * software without specific prior written permission. This software
10: * is provided ``as is'' without express or implied warranty.
11: *
12: * @(#)api_exch.h 3.2 (Berkeley) 3/28/88
13: */
14:
15: /*
16: * This file describes the structures passed back and forth
17: * between the API client and API server on a Unix-based
18: * tn3270 implementation.
19: */
20:
21: /*
22: * The following are the low-level opcodes exchanged between the
23: * two sides. These are designed to allow for type, sequence number,
24: * and direction checking.
25: *
26: * We enforce conversation flow. There are three states: CONTENTION,
27: * SEND, and RECEIVE. Both sides start in CONTENTION.
28: * We never leave RECEIVE state without first reading a TURNAROUND
29: * opcode. We never leave SEND state without first writing a TURNAROUND
30: * opcode. This scheme ensures that we always have conversation flowing
31: * in a synchronized direction (or detect an application error), and that
32: * we never hang with both sides trying to read from the "wire".
33: *
34: * State event action
35: *
36: * CONTENTION read request send TURNAROUND
37: * read RTS
38: * enter RECEIVE
39: * CONTENTION write request send RTS
40: * read TURNAROUND
41: * enter SEND
42: *
43: * RECEIVE read request read whatever
44: * RECEIVE write request read TURNAROUND
45: *
46: * SEND read request send TURNAROUND
47: * SEND write write whatever
48: */
49:
50: #define EXCH_EXCH_COMMAND 0 /* The following is a command */
51: #define EXCH_EXCH_TURNAROUND 1 /* Your turn to send */
52: #define EXCH_EXCH_RTS 2 /* Request to send */
53: #define EXCH_EXCH_TYPE 3 /* The following is a type */
54:
55: struct exch_exch {
56: unsigned char
57: opcode, /* COMMAND, TURNAROUND, or TYPE */
58: my_sequence, /* 0-ff, initially zero */
59: your_sequence, /* 0-ff, initially zero */
60: command_or_type; /* Application level command or type */
61: unsigned short
62: length; /* The length of any following data */
63: };
64:
65: /*
66: * The following are the command codes which the higher level protocols
67: * send and receive.
68: */
69:
70: #define EXCH_CMD_ASSOCIATE 0 /* Connect [client->server] */
71: /*
72: * struct storage_desc
73: * char key[]
74: */
75: #define EXCH_CMD_DISASSOCIATE 1 /* Disconnect [client->server] */
76: #define EXCH_CMD_SEND_AUTH 2 /* Send password [server->client] */
77: /*
78: * struct storage_desc
79: * char prompt[]
80: * struct storage_desc
81: * char seed[]
82: */
83: #define EXCH_CMD_AUTH 3 /* Authorization [client->server] */
84: /*
85: * struct storage_desc
86: * char authenticator[]
87: */
88: #define EXCH_CMD_ASSOCIATED 4 /* Connected [server->client] */
89: #define EXCH_CMD_REJECTED 5 /* Too bad [server->client] */
90: /*
91: * struct storage_desc
92: * char message[]
93: */
94:
95: #define EXCH_CMD_REQUEST 6 /* A request [client->server] */
96: /* struct regs,
97: * struct sregs,
98: * struct storage_desc
99: * char bytes[]
100: */
101: #define EXCH_CMD_GIMME 7 /* Send storage [server->client] */
102: /*
103: * struct storage_desc
104: */
105: #define EXCH_CMD_HEREIS 8 /* Here is storage [BOTH WAYS] */
106: /*
107: * struct storage_desc
108: * char bytes[]
109: */
110: #define EXCH_CMD_REPLY 9 /* End of discussion */
111: /*
112: * struct regs,
113: * struct sregs,
114: */
115:
116: /*
117: * The following are typed parameters sent across the wire.
118: *
119: * This should be done much more generally, with some form of
120: * XDR or mapped conversation ability.
121: */
122:
123: #define EXCH_TYPE_REGS 0
124: #define EXCH_TYPE_SREGS 1
125: #define EXCH_TYPE_STORE_DESC 2
126: #define EXCH_TYPE_BYTES 3
127:
128: /*
129: * each parameter that comes over looks like:
130: *
131: * char type of following
132: * short (2 bytes) length of following (network byte order)
133: * following
134: */
135:
136: struct storage_descriptor {
137: long location; /* In network byte order */
138: short length; /* In network byte order */
139: };
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