/* $OpenBSD: api_exch.c,v 1.2 1996/06/26 05:41:00 deraadt Exp $ */ /*- * Copyright (c) 1988 The Regents of the University of California. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #ifndef lint /*static char sccsid[] = "from: @(#)api_exch.c 4.2 (Berkeley) 4/26/91";*/ static char rcsid[] = "$OpenBSD: api_exch.c,v 1.2 1996/06/26 05:41:00 deraadt Exp $"; #endif /* not lint */ #include #include "../general/general.h" #include "api_exch.h" static int sock; /* Socket number */ static char whoarewe[40] = ""; #define WHO_ARE_WE() fprintf(stderr, "(API %s) ", whoarewe); static enum {CONTENTION, SEND, RECEIVE } conversation; static struct exch_exch exch_state; static unsigned int my_sequence, your_sequence; static char ibuffer[4000], *ibuf_next, *ibuf_last; #define IBUFADDED(i) ibuf_last += (i) #define IBUFAVAILABLE() (ibuf_last-ibuf_next) #define IBUFFER() ibuffer #define IBUFFREE() (ibuffer+sizeof ibuffer-ibuf_last-1) #define IBUFGETBYTES(w,l) { memcpy(w, ibuf_next, l); ibuf_next += l; } #define IBUFRESET() (ibuf_next = ibuf_last = ibuffer) char obuffer[4000], *obuf_next; #define OBUFADDBYTES(w,l) { memcpy(obuf_next, w, l); obuf_next += l; } #define OBUFAVAILABLE() (obuf_next - obuffer) #define OBUFFER() obuffer #define OBUFRESET() obuf_next = obuffer #define OBUFROOM() (obuffer+sizeof obuffer-obuf_next) static int outflush() { int length = OBUFAVAILABLE(); if (length != 0) { if (write(sock, OBUFFER(), length) != length) { WHO_ARE_WE(); perror("write"); return -1; } OBUFRESET(); } return 0; /* All OK */ } static int iget(location, length) char *location; int length; { int count; if (OBUFAVAILABLE()) { if (outflush() == -1) { return -1; } } if ((count = IBUFAVAILABLE()) != 0) { if (count > length) { count = length; } IBUFGETBYTES(location, count); length -= count; location += count; } while (length) { if (ibuf_next == ibuf_last) { IBUFRESET(); } if ((count = read(sock, IBUFFER(), IBUFFREE())) < 0) { WHO_ARE_WE(); perror("read"); return -1; } if (count == 0) { /* Reading past end-of-file */ WHO_ARE_WE(); fprintf(stderr, "End of file read\r\n"); return -1; } IBUFADDED(count); if (count > length) { count = length; } IBUFGETBYTES(location, count); length -= count; location += count; } return 0; } static char * exch_to_ascii(exch) int exch; /* opcode to decode */ { switch (exch) { case EXCH_EXCH_COMMAND: return "Command"; case EXCH_EXCH_TYPE: return "Type"; case EXCH_EXCH_TURNAROUND: return "Turnaround"; case EXCH_EXCH_RTS: return "Request to Send"; default: { static char unknown[40]; sprintf(unknown, "(Unknown exchange 0x%02x)", exch&0xff); return unknown; } } } /* * Send the exch structure, updating the sequnce number field. */ static int send_state() { if (OBUFROOM() < sizeof exch_state) { if (outflush() == -1) { return -1; } } my_sequence = (my_sequence+1)&0xff; exch_state.my_sequence = my_sequence; exch_state.your_sequence = your_sequence; OBUFADDBYTES((char *)&exch_state, sizeof exch_state); return 0; } /* * Receive the exch structure from the other side, checking * sequence numbering. */ static int receive_state() { if (iget((char *)&exch_state, sizeof exch_state) == -1) { return -1; } if (conversation != CONTENTION) { if (exch_state.your_sequence != my_sequence) { WHO_ARE_WE(); fprintf(stderr, "Send sequence number mismatch.\n"); return -1; } if (exch_state.my_sequence != ((++your_sequence)&0xff)) { WHO_ARE_WE(); fprintf(stderr, "Receive sequence number mismatch.\n"); return -1; } } your_sequence = exch_state.my_sequence; return 0; } static int enter_receive() { switch (conversation) { case CONTENTION: exch_state.opcode = EXCH_EXCH_TURNAROUND; if (send_state() == -1) { return -1; } if (receive_state() == -1) { return -1; } if (exch_state.opcode != EXCH_EXCH_RTS) { WHO_ARE_WE(); fprintf(stderr, "In CONTENTION state: "); if (exch_state.opcode == EXCH_EXCH_TURNAROUND) { fprintf(stderr, "Both sides tried to enter RECEIVE state.\n"); } else { fprintf(stderr, "Protocol error trying to enter RECEIVE state.\n"); } return -1; } break; case SEND: exch_state.opcode = EXCH_EXCH_TURNAROUND; if (send_state() == -1) { return -1; } break; } conversation = RECEIVE; return 0; } static int enter_send() { switch (conversation) { case CONTENTION: exch_state.opcode = EXCH_EXCH_RTS; if (send_state() == -1) { return -1; } /* fall through */ case RECEIVE: if (receive_state() == -1) { return -1; } if (exch_state.opcode != EXCH_EXCH_TURNAROUND) { WHO_ARE_WE(); fprintf(stderr, "Conversation error - both sides in SEND state.\n"); return -1; } } conversation = SEND; return 0; } int api_exch_nextcommand() { if (conversation != RECEIVE) { if (enter_receive() == -1) { return -1; } } if (receive_state() == -1) { return -1; } if (exch_state.opcode != EXCH_EXCH_COMMAND) { WHO_ARE_WE(); fprintf(stderr, "Expected a %s exchange, received a %s exchange.\n", exch_to_ascii(EXCH_EXCH_COMMAND), exch_to_ascii(exch_state.opcode)); return -1; } return exch_state.command_or_type; } int api_exch_incommand(command) int command; { int i; if ((i = api_exch_nextcommand()) == -1) { return -1; } if (i != command) { WHO_ARE_WE(); fprintf(stderr, "Expected API command 0x%x, got API command 0x%x.\n", command, i); return -1; } return 0; } int api_exch_outcommand(command) int command; { if (conversation != SEND) { if (enter_send() == -1) { return -1; } } exch_state.command_or_type = command; exch_state.opcode = EXCH_EXCH_COMMAND; if (send_state() == -1) { return -1; } else { return 0; } } int api_exch_outtype(type, length, location) int type, length; char *location; { int netleng = length; if (conversation != SEND) { if (enter_send() == -1) { return -1; } } exch_state.opcode = EXCH_EXCH_TYPE; exch_state.command_or_type = type; exch_state.length = netleng; if (send_state() == -1) { return -1; } if (length) { if (OBUFROOM() > length) { OBUFADDBYTES(location, length); } else { if (outflush() == -1) { return -1; } if (write(sock, location, length) != length) { WHO_ARE_WE(); perror("write"); return -1; } } } return 0; } int api_exch_intype(type, length, location) int type, length; char *location; { int netleng = length; if (conversation != RECEIVE) { if (enter_receive() == -1) { return -1; } } if (receive_state() == -1) { return -1; } if (exch_state.opcode != EXCH_EXCH_TYPE) { WHO_ARE_WE(); fprintf(stderr, "Expected to receive a %s exchange, received a %s exchange.\n", exch_to_ascii(EXCH_EXCH_TYPE), exch_to_ascii(exch_state.opcode)); return -1; } if (exch_state.command_or_type != type) { WHO_ARE_WE(); fprintf(stderr, "Expected type 0x%x, got type 0x%x.\n", type, exch_state.command_or_type); return -1; } if (exch_state.length != netleng) { fprintf(stderr, "Type 0x%x - expected length %d, received length %u.\n", type, length, exch_state.length); return -1; } if (iget(location, length) == -1) { return -1; } return 0; } int api_exch_flush() { return outflush(); } int api_exch_init(sock_number, ourname) int sock_number; char *ourname; { extern char *strcpy(); sock = sock_number; (void) strcpy(whoarewe, ourname); /* For error messages */ my_sequence = your_sequence = 0; conversation = CONTENTION; /* We don't know which direction */ IBUFRESET(); OBUFRESET(); return 0; }