1 /* 2 * This file describes the structures passed back and forth 3 * between the API client and API server on a Unix-based 4 * tn3270 implementation. 5 * 6 */ 7 8 /* 9 * The following are the low-level opcodes exchanged between the 10 * two sides. These are designed to allow for type, sequence number, 11 * and direction checking. 12 * 13 * We enforce conversation flow. There are three states: CONTENTION, 14 * SEND, and RECEIVE. Both sides start in CONTENTION. 15 * We never leave RECEIVE state without first reading a TURNAROUND 16 * opcode. We never leave SEND state without first writing a TURNAROUND 17 * opcode. This scheme ensures that we always have conversation flowing 18 * in a synchronized direction (or detect an application error), and that 19 * we never hang with both sides trying to read from the "wire". 20 * 21 * State event action 22 * 23 * CONTENTION read request send TURNAROUND 24 * read RTS 25 * enter RECEIVE 26 * CONTENTION write request send RTS 27 * read TURNAROUND 28 * enter SEND 29 * 30 * RECEIVE read request read whatever 31 * RECEIVE write request read TURNAROUND 32 * 33 * SEND read request send TURNAROUND 34 * SEND write write whatever 35 */ 36 37 #define EXCH_EXCH_COMMAND 0 /* The following is a command */ 38 #define EXCH_EXCH_TURNAROUND 1 /* Your turn to send */ 39 #define EXCH_EXCH_RTS 2 /* Request to send */ 40 #define EXCH_EXCH_TYPE 3 /* The following is a type */ 41 42 struct exch_exch { 43 unsigned char 44 opcode, /* COMMAND, TURNAROUND, or TYPE */ 45 my_sequence, /* 0-ff, initially zero */ 46 your_sequence, /* 0-ff, initially zero */ 47 command_or_type; /* Application level command or type */ 48 unsigned short 49 length; /* The length of any following data */ 50 }; 51 52 /* 53 * The following are the command codes which the higher level protocols 54 * send and receive. 55 */ 56 57 #define EXCH_CMD_ASSOCIATE 0 /* Connect [client->server] */ 58 #define EXCH_CMD_DISASSOCIATE 1 /* Disconnect [client->server] */ 59 #define EXCH_CMD_SEND_AUTH 2 /* Send password [server->client] */ 60 /* 61 * struct storeage_desc 62 * char prompt[] 63 * struct storeage_desc 64 * char seed[] 65 */ 66 #define EXCH_CMD_AUTH 3 /* Authorization [client->server] */ 67 /* 68 * struct storeage_desc 69 * char authenticator[] 70 */ 71 #define EXCH_CMD_ASSOCIATED 4 /* Connected [server->client] */ 72 #define EXCH_CMD_REJECTED 5 /* Too bad [server->client] */ 73 /* 74 * struct storeage_desc 75 * char message[] 76 */ 77 78 #define EXCH_CMD_REQUEST 6 /* A request [client->server] */ 79 /* struct regs, 80 * struct sregs, 81 * struct storage_desc 82 * char bytes[] 83 */ 84 #define EXCH_CMD_GIMME 7 /* Send storage [server->client] */ 85 /* 86 * struct storage_desc 87 */ 88 #define EXCH_CMD_HEREIS 8 /* Here is storage [BOTH WAYS] */ 89 /* 90 * struct storage_desc 91 * char bytes[] 92 */ 93 #define EXCH_CMD_REPLY 9 /* End of discussion */ 94 /* 95 * struct regs, 96 * struct sregs, 97 */ 98 99 /* 100 * The following are typed parameters sent across the wire. 101 * 102 * This should be done much more generally, with some form of 103 * XDR or mapped conversation ability. 104 */ 105 106 #define EXCH_TYPE_REGS 0 107 #define EXCH_TYPE_SREGS 1 108 #define EXCH_TYPE_STORE_DESC 2 109 #define EXCH_TYPE_BYTES 3 110 111 /* 112 * each parameter that comes over looks like: 113 * 114 * char type of following 115 * short (2 bytes) length of following (network byte order) 116 * following 117 */ 118 119 struct storage_descriptor { 120 long location; /* In network byte order */ 121 short length; /* In network byte order */ 122 }; 123