1 /* $OpenBSD: tftpsubs.c,v 1.2 1996/06/26 05:40:36 deraadt Exp $ */ 2 /* $NetBSD: tftpsubs.c,v 1.3 1994/12/08 09:51:31 jtc Exp $ */ 3 4 /* 5 * Copyright (c) 1983, 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 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 the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37 #ifndef lint 38 #if 0 39 static char sccsid[] = "@(#)tftpsubs.c 8.1 (Berkeley) 6/6/93"; 40 #endif 41 static char rcsid[] = "$OpenBSD: tftpsubs.c,v 1.2 1996/06/26 05:40:36 deraadt Exp $"; 42 #endif /* not lint */ 43 44 /* Simple minded read-ahead/write-behind subroutines for tftp user and 45 server. Written originally with multiple buffers in mind, but current 46 implementation has two buffer logic wired in. 47 48 Todo: add some sort of final error check so when the write-buffer 49 is finally flushed, the caller can detect if the disk filled up 50 (or had an i/o error) and return a nak to the other side. 51 52 Jim Guyton 10/85 53 */ 54 55 #include <sys/types.h> 56 #include <sys/socket.h> 57 #include <sys/ioctl.h> 58 #include <netinet/in.h> 59 #include <arpa/tftp.h> 60 61 #include <stdio.h> 62 #include <unistd.h> 63 64 #include "tftpsubs.h" 65 66 #define PKTSIZE SEGSIZE+4 /* should be moved to tftp.h */ 67 68 struct bf { 69 int counter; /* size of data in buffer, or flag */ 70 char buf[PKTSIZE]; /* room for data packet */ 71 } bfs[2]; 72 73 /* Values for bf.counter */ 74 #define BF_ALLOC -3 /* alloc'd but not yet filled */ 75 #define BF_FREE -2 /* free */ 76 /* [-1 .. SEGSIZE] = size of data in the data buffer */ 77 78 static int nextone; /* index of next buffer to use */ 79 static int current; /* index of buffer in use */ 80 81 /* control flags for crlf conversions */ 82 int newline = 0; /* fillbuf: in middle of newline expansion */ 83 int prevchar = -1; /* putbuf: previous char (cr check) */ 84 85 static struct tftphdr *rw_init(); 86 87 struct tftphdr *w_init() { return rw_init(0); } /* write-behind */ 88 struct tftphdr *r_init() { return rw_init(1); } /* read-ahead */ 89 90 static struct tftphdr * 91 rw_init(x) /* init for either read-ahead or write-behind */ 92 int x; /* zero for write-behind, one for read-head */ 93 { 94 newline = 0; /* init crlf flag */ 95 prevchar = -1; 96 bfs[0].counter = BF_ALLOC; /* pass out the first buffer */ 97 current = 0; 98 bfs[1].counter = BF_FREE; 99 nextone = x; /* ahead or behind? */ 100 return (struct tftphdr *)bfs[0].buf; 101 } 102 103 104 /* Have emptied current buffer by sending to net and getting ack. 105 Free it and return next buffer filled with data. 106 */ 107 int 108 readit(file, dpp, convert) 109 FILE *file; /* file opened for read */ 110 struct tftphdr **dpp; 111 int convert; /* if true, convert to ascii */ 112 { 113 struct bf *b; 114 115 bfs[current].counter = BF_FREE; /* free old one */ 116 current = !current; /* "incr" current */ 117 118 b = &bfs[current]; /* look at new buffer */ 119 if (b->counter == BF_FREE) /* if it's empty */ 120 read_ahead(file, convert); /* fill it */ 121 /* assert(b->counter != BF_FREE);*//* check */ 122 *dpp = (struct tftphdr *)b->buf; /* set caller's ptr */ 123 return b->counter; 124 } 125 126 /* 127 * fill the input buffer, doing ascii conversions if requested 128 * conversions are lf -> cr,lf and cr -> cr, nul 129 */ 130 void 131 read_ahead(file, convert) 132 FILE *file; /* file opened for read */ 133 int convert; /* if true, convert to ascii */ 134 { 135 register int i; 136 register char *p; 137 register int c; 138 struct bf *b; 139 struct tftphdr *dp; 140 141 b = &bfs[nextone]; /* look at "next" buffer */ 142 if (b->counter != BF_FREE) /* nop if not free */ 143 return; 144 nextone = !nextone; /* "incr" next buffer ptr */ 145 146 dp = (struct tftphdr *)b->buf; 147 148 if (convert == 0) { 149 b->counter = read(fileno(file), dp->th_data, SEGSIZE); 150 return; 151 } 152 153 p = dp->th_data; 154 for (i = 0 ; i < SEGSIZE; i++) { 155 if (newline) { 156 if (prevchar == '\n') 157 c = '\n'; /* lf to cr,lf */ 158 else c = '\0'; /* cr to cr,nul */ 159 newline = 0; 160 } 161 else { 162 c = getc(file); 163 if (c == EOF) break; 164 if (c == '\n' || c == '\r') { 165 prevchar = c; 166 c = '\r'; 167 newline = 1; 168 } 169 } 170 *p++ = c; 171 } 172 b->counter = (int)(p - dp->th_data); 173 } 174 175 /* Update count associated with the buffer, get new buffer 176 from the queue. Calls write_behind only if next buffer not 177 available. 178 */ 179 int 180 writeit(file, dpp, ct, convert) 181 FILE *file; 182 struct tftphdr **dpp; 183 int ct, convert; 184 { 185 bfs[current].counter = ct; /* set size of data to write */ 186 current = !current; /* switch to other buffer */ 187 if (bfs[current].counter != BF_FREE) /* if not free */ 188 (void)write_behind(file, convert); /* flush it */ 189 bfs[current].counter = BF_ALLOC; /* mark as alloc'd */ 190 *dpp = (struct tftphdr *)bfs[current].buf; 191 return ct; /* this is a lie of course */ 192 } 193 194 /* 195 * Output a buffer to a file, converting from netascii if requested. 196 * CR,NUL -> CR and CR,LF => LF. 197 * Note spec is undefined if we get CR as last byte of file or a 198 * CR followed by anything else. In this case we leave it alone. 199 */ 200 int 201 write_behind(file, convert) 202 FILE *file; 203 int convert; 204 { 205 char *buf; 206 int count; 207 register int ct; 208 register char *p; 209 register int c; /* current character */ 210 struct bf *b; 211 struct tftphdr *dp; 212 213 b = &bfs[nextone]; 214 if (b->counter < -1) /* anything to flush? */ 215 return 0; /* just nop if nothing to do */ 216 217 count = b->counter; /* remember byte count */ 218 b->counter = BF_FREE; /* reset flag */ 219 dp = (struct tftphdr *)b->buf; 220 nextone = !nextone; /* incr for next time */ 221 buf = dp->th_data; 222 223 if (count <= 0) return -1; /* nak logic? */ 224 225 if (convert == 0) 226 return write(fileno(file), buf, count); 227 228 p = buf; 229 ct = count; 230 while (ct--) { /* loop over the buffer */ 231 c = *p++; /* pick up a character */ 232 if (prevchar == '\r') { /* if prev char was cr */ 233 if (c == '\n') /* if have cr,lf then just */ 234 fseek(file, -1, 1); /* smash lf on top of the cr */ 235 else 236 if (c == '\0') /* if have cr,nul then */ 237 goto skipit; /* just skip over the putc */ 238 /* else just fall through and allow it */ 239 } 240 putc(c, file); 241 skipit: 242 prevchar = c; 243 } 244 return count; 245 } 246 247 248 /* When an error has occurred, it is possible that the two sides 249 * are out of synch. Ie: that what I think is the other side's 250 * response to packet N is really their response to packet N-1. 251 * 252 * So, to try to prevent that, we flush all the input queued up 253 * for us on the network connection on our host. 254 * 255 * We return the number of packets we flushed (mostly for reporting 256 * when trace is active). 257 */ 258 259 int 260 synchnet(f) 261 int f; /* socket to flush */ 262 { 263 int i, j = 0; 264 char rbuf[PKTSIZE]; 265 struct sockaddr_in from; 266 int fromlen; 267 268 while (1) { 269 (void) ioctl(f, FIONREAD, &i); 270 if (i) { 271 j++; 272 fromlen = sizeof from; 273 (void) recvfrom(f, rbuf, sizeof (rbuf), 0, 274 (struct sockaddr *)&from, &fromlen); 275 } else { 276 return(j); 277 } 278 } 279 } 280