Annotation of src/usr.bin/ssh/packet.c, Revision 1.20
1.1 deraadt 1: /*
1.15 deraadt 2: *
3: * packet.c
4: *
5: * Author: Tatu Ylonen <ylo@cs.hut.fi>
6: *
7: * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
8: * All rights reserved
9: *
10: * Created: Sat Mar 18 02:40:40 1995 ylo
11: *
12: * This file contains code implementing the packet protocol and communication
13: * with the other side. This same code is used both on client and server side.
14: *
15: */
1.1 deraadt 16:
17: #include "includes.h"
1.20 ! markus 18: RCSID("$Id: packet.c,v 1.19 2000/01/04 00:07:59 markus Exp $");
1.1 deraadt 19:
20: #include "xmalloc.h"
21: #include "buffer.h"
22: #include "packet.h"
23: #include "bufaux.h"
24: #include "ssh.h"
25: #include "crc32.h"
26: #include "cipher.h"
27: #include "getput.h"
28:
29: #include "compress.h"
1.9 dugsong 30: #include "deattack.h"
1.1 deraadt 31:
1.16 markus 32: /*
33: * This variable contains the file descriptors used for communicating with
34: * the other side. connection_in is used for reading; connection_out for
35: * writing. These can be the same descriptor, in which case it is assumed to
36: * be a socket.
37: */
1.1 deraadt 38: static int connection_in = -1;
39: static int connection_out = -1;
40:
1.16 markus 41: /*
42: * Cipher type. This value is only used to determine whether to pad the
43: * packets with zeroes or random data.
44: */
1.1 deraadt 45: static int cipher_type = SSH_CIPHER_NONE;
46:
47: /* Protocol flags for the remote side. */
48: static unsigned int remote_protocol_flags = 0;
49:
50: /* Encryption context for receiving data. This is only used for decryption. */
51: static CipherContext receive_context;
1.14 markus 52:
53: /* Encryption context for sending data. This is only used for encryption. */
1.1 deraadt 54: static CipherContext send_context;
55:
56: /* Buffer for raw input data from the socket. */
57: static Buffer input;
58:
59: /* Buffer for raw output data going to the socket. */
60: static Buffer output;
61:
62: /* Buffer for the partial outgoing packet being constructed. */
63: static Buffer outgoing_packet;
64:
65: /* Buffer for the incoming packet currently being processed. */
66: static Buffer incoming_packet;
67:
68: /* Scratch buffer for packet compression/decompression. */
69: static Buffer compression_buffer;
70:
71: /* Flag indicating whether packet compression/decompression is enabled. */
72: static int packet_compression = 0;
73:
1.12 markus 74: /* default maximum packet size */
75: int max_packet_size = 32768;
76:
1.1 deraadt 77: /* Flag indicating whether this module has been initialized. */
78: static int initialized = 0;
79:
80: /* Set to true if the connection is interactive. */
81: static int interactive_mode = 0;
82:
1.16 markus 83: /*
84: * Sets the descriptors used for communication. Disables encryption until
85: * packet_set_encryption_key is called.
86: */
1.1 deraadt 87:
1.2 provos 88: void
89: packet_set_connection(int fd_in, int fd_out)
1.1 deraadt 90: {
1.14 markus 91: connection_in = fd_in;
92: connection_out = fd_out;
93: cipher_type = SSH_CIPHER_NONE;
94: cipher_set_key(&send_context, SSH_CIPHER_NONE, (unsigned char *) "", 0, 1);
95: cipher_set_key(&receive_context, SSH_CIPHER_NONE, (unsigned char *) "", 0, 0);
96: if (!initialized) {
97: initialized = 1;
98: buffer_init(&input);
99: buffer_init(&output);
100: buffer_init(&outgoing_packet);
101: buffer_init(&incoming_packet);
102: }
103: /* Kludge: arrange the close function to be called from fatal(). */
104: fatal_add_cleanup((void (*) (void *)) packet_close, NULL);
1.1 deraadt 105: }
106:
1.19 markus 107: /* Returns 1 if remote host is connected via socket, 0 if not. */
108:
109: int
110: packet_connection_is_on_socket()
111: {
112: struct sockaddr_storage from, to;
113: socklen_t fromlen, tolen;
114:
115: /* filedescriptors in and out are the same, so it's a socket */
116: if (connection_in == connection_out)
117: return 1;
118: fromlen = sizeof(from);
119: memset(&from, 0, sizeof(from));
1.20 ! markus 120: if (getpeername(connection_in, (struct sockaddr *)&from, &fromlen) < 0)
1.19 markus 121: return 0;
122: tolen = sizeof(to);
123: memset(&to, 0, sizeof(to));
1.20 ! markus 124: if (getpeername(connection_out, (struct sockaddr *)&to, &tolen) < 0)
1.19 markus 125: return 0;
126: if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0)
127: return 0;
128: if (from.ss_family != AF_INET && from.ss_family != AF_INET6)
129: return 0;
130: return 1;
131: }
132:
133: /* returns 1 if connection is via ipv4 */
134:
135: int
136: packet_connection_is_ipv4()
137: {
138: struct sockaddr_storage to;
139: socklen_t tolen;
140:
141: memset(&to, 0, sizeof(to));
142: if (getsockname(connection_out, (struct sockaddr *)&to, &tolen) < 0)
143: return 0;
144: if (to.ss_family != AF_INET)
145: return 0;
146: return 1;
147: }
148:
1.1 deraadt 149: /* Sets the connection into non-blocking mode. */
150:
1.2 provos 151: void
152: packet_set_nonblocking()
1.1 deraadt 153: {
1.14 markus 154: /* Set the socket into non-blocking mode. */
155: if (fcntl(connection_in, F_SETFL, O_NONBLOCK) < 0)
156: error("fcntl O_NONBLOCK: %.100s", strerror(errno));
157:
158: if (connection_out != connection_in) {
159: if (fcntl(connection_out, F_SETFL, O_NONBLOCK) < 0)
160: error("fcntl O_NONBLOCK: %.100s", strerror(errno));
161: }
1.1 deraadt 162: }
163:
164: /* Returns the socket used for reading. */
165:
1.2 provos 166: int
167: packet_get_connection_in()
1.1 deraadt 168: {
1.14 markus 169: return connection_in;
1.1 deraadt 170: }
171:
172: /* Returns the descriptor used for writing. */
173:
1.2 provos 174: int
175: packet_get_connection_out()
1.1 deraadt 176: {
1.14 markus 177: return connection_out;
1.1 deraadt 178: }
179:
180: /* Closes the connection and clears and frees internal data structures. */
181:
1.2 provos 182: void
183: packet_close()
1.1 deraadt 184: {
1.14 markus 185: if (!initialized)
186: return;
187: initialized = 0;
188: if (connection_in == connection_out) {
189: shutdown(connection_out, SHUT_RDWR);
190: close(connection_out);
191: } else {
192: close(connection_in);
193: close(connection_out);
194: }
195: buffer_free(&input);
196: buffer_free(&output);
197: buffer_free(&outgoing_packet);
198: buffer_free(&incoming_packet);
199: if (packet_compression) {
200: buffer_free(&compression_buffer);
201: buffer_compress_uninit();
202: }
1.1 deraadt 203: }
204:
205: /* Sets remote side protocol flags. */
206:
1.2 provos 207: void
208: packet_set_protocol_flags(unsigned int protocol_flags)
1.1 deraadt 209: {
1.14 markus 210: remote_protocol_flags = protocol_flags;
211: channel_set_options((protocol_flags & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) != 0);
1.1 deraadt 212: }
213:
214: /* Returns the remote protocol flags set earlier by the above function. */
215:
1.2 provos 216: unsigned int
217: packet_get_protocol_flags()
1.1 deraadt 218: {
1.14 markus 219: return remote_protocol_flags;
1.1 deraadt 220: }
221:
1.16 markus 222: /*
223: * Starts packet compression from the next packet on in both directions.
224: * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip.
225: */
1.1 deraadt 226:
1.2 provos 227: void
228: packet_start_compression(int level)
1.1 deraadt 229: {
1.14 markus 230: if (packet_compression)
231: fatal("Compression already enabled.");
232: packet_compression = 1;
233: buffer_init(&compression_buffer);
234: buffer_compress_init(level);
1.1 deraadt 235: }
236:
1.16 markus 237: /*
238: * Encrypts the given number of bytes, copying from src to dest. bytes is
239: * known to be a multiple of 8.
240: */
1.1 deraadt 241:
1.2 provos 242: void
1.14 markus 243: packet_encrypt(CipherContext * cc, void *dest, void *src,
1.2 provos 244: unsigned int bytes)
1.1 deraadt 245: {
1.14 markus 246: cipher_encrypt(cc, dest, src, bytes);
1.1 deraadt 247: }
248:
1.16 markus 249: /*
250: * Decrypts the given number of bytes, copying from src to dest. bytes is
251: * known to be a multiple of 8.
252: */
1.1 deraadt 253:
1.2 provos 254: void
1.14 markus 255: packet_decrypt(CipherContext * cc, void *dest, void *src,
1.2 provos 256: unsigned int bytes)
1.1 deraadt 257: {
1.14 markus 258: int i;
259:
260: if ((bytes % 8) != 0)
261: fatal("packet_decrypt: bad ciphertext length %d", bytes);
262:
1.16 markus 263: /*
264: * Cryptographic attack detector for ssh - Modifications for packet.c
265: * (C)1998 CORE-SDI, Buenos Aires Argentina Ariel Futoransky(futo@core-sdi.com)
266: */
1.14 markus 267:
268: switch (cc->type) {
269: case SSH_CIPHER_NONE:
270: i = DEATTACK_OK;
271: break;
272: default:
273: i = detect_attack(src, bytes, NULL);
274: break;
275: }
276:
277: if (i == DEATTACK_DETECTED)
278: packet_disconnect("crc32 compensation attack: network attack detected");
279:
280: cipher_decrypt(cc, dest, src, bytes);
1.1 deraadt 281: }
282:
1.16 markus 283: /*
284: * Causes any further packets to be encrypted using the given key. The same
285: * key is used for both sending and reception. However, both directions are
286: * encrypted independently of each other.
287: */
1.1 deraadt 288:
1.2 provos 289: void
290: packet_set_encryption_key(const unsigned char *key, unsigned int keylen,
1.11 markus 291: int cipher)
1.1 deraadt 292: {
1.14 markus 293: /* All other ciphers use the same key in both directions for now. */
294: cipher_set_key(&receive_context, cipher, key, keylen, 0);
295: cipher_set_key(&send_context, cipher, key, keylen, 1);
1.1 deraadt 296: }
297:
298: /* Starts constructing a packet to send. */
299:
1.2 provos 300: void
301: packet_start(int type)
1.1 deraadt 302: {
1.14 markus 303: char buf[9];
1.1 deraadt 304:
1.14 markus 305: buffer_clear(&outgoing_packet);
306: memset(buf, 0, 8);
307: buf[8] = type;
308: buffer_append(&outgoing_packet, buf, 9);
1.1 deraadt 309: }
310:
311: /* Appends a character to the packet data. */
312:
1.2 provos 313: void
314: packet_put_char(int value)
1.1 deraadt 315: {
1.14 markus 316: char ch = value;
317: buffer_append(&outgoing_packet, &ch, 1);
1.1 deraadt 318: }
319:
320: /* Appends an integer to the packet data. */
321:
1.2 provos 322: void
323: packet_put_int(unsigned int value)
1.1 deraadt 324: {
1.14 markus 325: buffer_put_int(&outgoing_packet, value);
1.1 deraadt 326: }
327:
328: /* Appends a string to packet data. */
329:
1.2 provos 330: void
331: packet_put_string(const char *buf, unsigned int len)
1.1 deraadt 332: {
1.14 markus 333: buffer_put_string(&outgoing_packet, buf, len);
1.1 deraadt 334: }
335:
336: /* Appends an arbitrary precision integer to packet data. */
337:
1.2 provos 338: void
1.14 markus 339: packet_put_bignum(BIGNUM * value)
1.1 deraadt 340: {
1.14 markus 341: buffer_put_bignum(&outgoing_packet, value);
1.1 deraadt 342: }
343:
1.16 markus 344: /*
345: * Finalizes and sends the packet. If the encryption key has been set,
346: * encrypts the packet before sending.
347: */
1.14 markus 348:
1.2 provos 349: void
350: packet_send()
1.1 deraadt 351: {
1.14 markus 352: char buf[8], *cp;
353: int i, padding, len;
354: unsigned int checksum;
355: u_int32_t rand = 0;
356:
1.16 markus 357: /*
358: * If using packet compression, compress the payload of the outgoing
359: * packet.
360: */
1.14 markus 361: if (packet_compression) {
362: buffer_clear(&compression_buffer);
363: /* Skip padding. */
364: buffer_consume(&outgoing_packet, 8);
365: /* padding */
366: buffer_append(&compression_buffer, "\0\0\0\0\0\0\0\0", 8);
367: buffer_compress(&outgoing_packet, &compression_buffer);
368: buffer_clear(&outgoing_packet);
369: buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer),
370: buffer_len(&compression_buffer));
371: }
372: /* Compute packet length without padding (add checksum, remove padding). */
373: len = buffer_len(&outgoing_packet) + 4 - 8;
374:
375: /* Insert padding. */
376: padding = 8 - len % 8;
377: if (cipher_type != SSH_CIPHER_NONE) {
378: cp = buffer_ptr(&outgoing_packet);
379: for (i = 0; i < padding; i++) {
380: if (i % 4 == 0)
381: rand = arc4random();
382: cp[7 - i] = rand & 0xff;
383: rand >>= 8;
384: }
385: }
386: buffer_consume(&outgoing_packet, 8 - padding);
387:
388: /* Add check bytes. */
389: checksum = crc32((unsigned char *) buffer_ptr(&outgoing_packet),
390: buffer_len(&outgoing_packet));
391: PUT_32BIT(buf, checksum);
392: buffer_append(&outgoing_packet, buf, 4);
1.1 deraadt 393:
394: #ifdef PACKET_DEBUG
1.14 markus 395: fprintf(stderr, "packet_send plain: ");
396: buffer_dump(&outgoing_packet);
1.1 deraadt 397: #endif
398:
1.14 markus 399: /* Append to output. */
400: PUT_32BIT(buf, len);
401: buffer_append(&output, buf, 4);
402: buffer_append_space(&output, &cp, buffer_len(&outgoing_packet));
403: packet_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet),
404: buffer_len(&outgoing_packet));
405:
1.1 deraadt 406: #ifdef PACKET_DEBUG
1.14 markus 407: fprintf(stderr, "encrypted: ");
408: buffer_dump(&output);
1.1 deraadt 409: #endif
410:
1.14 markus 411: buffer_clear(&outgoing_packet);
1.1 deraadt 412:
1.16 markus 413: /*
414: * Note that the packet is now only buffered in output. It won\'t be
415: * actually sent until packet_write_wait or packet_write_poll is
416: * called.
417: */
1.1 deraadt 418: }
419:
1.16 markus 420: /*
421: * Waits until a packet has been received, and returns its type. Note that
422: * no other data is processed until this returns, so this function should not
423: * be used during the interactive session.
424: */
1.1 deraadt 425:
1.2 provos 426: int
427: packet_read(int *payload_len_ptr)
1.1 deraadt 428: {
1.14 markus 429: int type, len;
430: fd_set set;
431: char buf[8192];
432:
433: /* Since we are blocking, ensure that all written packets have been sent. */
434: packet_write_wait();
435:
436: /* Stay in the loop until we have received a complete packet. */
437: for (;;) {
438: /* Try to read a packet from the buffer. */
439: type = packet_read_poll(payload_len_ptr);
440: if (type == SSH_SMSG_SUCCESS
441: || type == SSH_SMSG_FAILURE
442: || type == SSH_CMSG_EOF
443: || type == SSH_CMSG_EXIT_CONFIRMATION)
444: packet_integrity_check(*payload_len_ptr, 0, type);
445: /* If we got a packet, return it. */
446: if (type != SSH_MSG_NONE)
447: return type;
1.16 markus 448: /*
449: * Otherwise, wait for some data to arrive, add it to the
450: * buffer, and try again.
451: */
1.14 markus 452: FD_ZERO(&set);
453: FD_SET(connection_in, &set);
1.16 markus 454:
1.14 markus 455: /* Wait for some data to arrive. */
456: select(connection_in + 1, &set, NULL, NULL, NULL);
1.16 markus 457:
1.14 markus 458: /* Read data from the socket. */
459: len = read(connection_in, buf, sizeof(buf));
1.18 markus 460: if (len == 0) {
461: log("Connection closed by %.200s", get_remote_ipaddr());
462: fatal_cleanup();
463: }
1.14 markus 464: if (len < 0)
465: fatal("Read from socket failed: %.100s", strerror(errno));
466: /* Append it to the buffer. */
467: packet_process_incoming(buf, len);
468: }
469: /* NOTREACHED */
1.1 deraadt 470: }
471:
1.16 markus 472: /*
473: * Waits until a packet has been received, verifies that its type matches
474: * that given, and gives a fatal error and exits if there is a mismatch.
475: */
1.1 deraadt 476:
1.2 provos 477: void
478: packet_read_expect(int *payload_len_ptr, int expected_type)
1.1 deraadt 479: {
1.14 markus 480: int type;
1.1 deraadt 481:
1.14 markus 482: type = packet_read(payload_len_ptr);
483: if (type != expected_type)
484: packet_disconnect("Protocol error: expected packet type %d, got %d",
485: expected_type, type);
1.1 deraadt 486: }
487:
488: /* Checks if a full packet is available in the data received so far via
1.14 markus 489: * packet_process_incoming. If so, reads the packet; otherwise returns
490: * SSH_MSG_NONE. This does not wait for data from the connection.
491: *
492: * SSH_MSG_DISCONNECT is handled specially here. Also,
493: * SSH_MSG_IGNORE messages are skipped by this function and are never returned
494: * to higher levels.
495: *
496: * The returned payload_len does include space consumed by:
497: * Packet length
498: * Padding
499: * Packet type
500: * Check bytes
501: */
1.1 deraadt 502:
1.2 provos 503: int
504: packet_read_poll(int *payload_len_ptr)
1.1 deraadt 505: {
1.14 markus 506: unsigned int len, padded_len;
507: unsigned char *ucp;
508: char buf[8], *cp;
509: unsigned int checksum, stored_checksum;
510:
511: restart:
512:
513: /* Check if input size is less than minimum packet size. */
514: if (buffer_len(&input) < 4 + 8)
515: return SSH_MSG_NONE;
516: /* Get length of incoming packet. */
517: ucp = (unsigned char *) buffer_ptr(&input);
518: len = GET_32BIT(ucp);
519: if (len < 1 + 2 + 2 || len > 256 * 1024)
520: packet_disconnect("Bad packet length %d.", len);
521: padded_len = (len + 8) & ~7;
522:
523: /* Check if the packet has been entirely received. */
524: if (buffer_len(&input) < 4 + padded_len)
525: return SSH_MSG_NONE;
526:
527: /* The entire packet is in buffer. */
528:
529: /* Consume packet length. */
530: buffer_consume(&input, 4);
531:
532: /* Copy data to incoming_packet. */
533: buffer_clear(&incoming_packet);
534: buffer_append_space(&incoming_packet, &cp, padded_len);
535: packet_decrypt(&receive_context, cp, buffer_ptr(&input), padded_len);
536: buffer_consume(&input, padded_len);
1.1 deraadt 537:
538: #ifdef PACKET_DEBUG
1.14 markus 539: fprintf(stderr, "read_poll plain: ");
540: buffer_dump(&incoming_packet);
1.1 deraadt 541: #endif
542:
1.14 markus 543: /* Compute packet checksum. */
544: checksum = crc32((unsigned char *) buffer_ptr(&incoming_packet),
545: buffer_len(&incoming_packet) - 4);
546:
547: /* Skip padding. */
548: buffer_consume(&incoming_packet, 8 - len % 8);
549:
550: /* Test check bytes. */
551:
552: if (len != buffer_len(&incoming_packet))
553: packet_disconnect("packet_read_poll: len %d != buffer_len %d.",
554: len, buffer_len(&incoming_packet));
555:
556: ucp = (unsigned char *) buffer_ptr(&incoming_packet) + len - 4;
557: stored_checksum = GET_32BIT(ucp);
558: if (checksum != stored_checksum)
559: packet_disconnect("Corrupted check bytes on input.");
560: buffer_consume_end(&incoming_packet, 4);
561:
562: /* If using packet compression, decompress the packet. */
563: if (packet_compression) {
564: buffer_clear(&compression_buffer);
565: buffer_uncompress(&incoming_packet, &compression_buffer);
566: buffer_clear(&incoming_packet);
567: buffer_append(&incoming_packet, buffer_ptr(&compression_buffer),
568: buffer_len(&compression_buffer));
569: }
570: /* Get packet type. */
571: buffer_get(&incoming_packet, &buf[0], 1);
572:
573: /* Return length of payload (without type field). */
574: *payload_len_ptr = buffer_len(&incoming_packet);
575:
576: /* Handle disconnect message. */
1.17 markus 577: if ((unsigned char) buf[0] == SSH_MSG_DISCONNECT) {
578: log("Received disconnect: %.900s", packet_get_string(NULL));
579: fatal_cleanup();
580: }
1.14 markus 581:
582: /* Ignore ignore messages. */
583: if ((unsigned char) buf[0] == SSH_MSG_IGNORE)
584: goto restart;
585:
586: /* Send debug messages as debugging output. */
587: if ((unsigned char) buf[0] == SSH_MSG_DEBUG) {
588: debug("Remote: %.900s", packet_get_string(NULL));
589: goto restart;
590: }
591: /* Return type. */
592: return (unsigned char) buf[0];
1.1 deraadt 593: }
1.14 markus 594:
1.16 markus 595: /*
596: * Buffers the given amount of input characters. This is intended to be used
597: * together with packet_read_poll.
598: */
1.1 deraadt 599:
1.2 provos 600: void
601: packet_process_incoming(const char *buf, unsigned int len)
1.1 deraadt 602: {
1.14 markus 603: buffer_append(&input, buf, len);
1.1 deraadt 604: }
605:
606: /* Returns a character from the packet. */
607:
1.2 provos 608: unsigned int
609: packet_get_char()
1.1 deraadt 610: {
1.14 markus 611: char ch;
612: buffer_get(&incoming_packet, &ch, 1);
613: return (unsigned char) ch;
1.1 deraadt 614: }
615:
616: /* Returns an integer from the packet data. */
617:
1.2 provos 618: unsigned int
619: packet_get_int()
1.1 deraadt 620: {
1.14 markus 621: return buffer_get_int(&incoming_packet);
1.1 deraadt 622: }
623:
1.16 markus 624: /*
625: * Returns an arbitrary precision integer from the packet data. The integer
626: * must have been initialized before this call.
627: */
1.1 deraadt 628:
1.2 provos 629: void
1.14 markus 630: packet_get_bignum(BIGNUM * value, int *length_ptr)
1.1 deraadt 631: {
1.14 markus 632: *length_ptr = buffer_get_bignum(&incoming_packet, value);
1.1 deraadt 633: }
634:
1.16 markus 635: /*
636: * Returns a string from the packet data. The string is allocated using
637: * xmalloc; it is the responsibility of the calling program to free it when
638: * no longer needed. The length_ptr argument may be NULL, or point to an
639: * integer into which the length of the string is stored.
640: */
1.1 deraadt 641:
1.16 markus 642: char *
1.14 markus 643: packet_get_string(unsigned int *length_ptr)
1.1 deraadt 644: {
1.14 markus 645: return buffer_get_string(&incoming_packet, length_ptr);
1.1 deraadt 646: }
647:
1.16 markus 648: /*
649: * Sends a diagnostic message from the server to the client. This message
650: * can be sent at any time (but not while constructing another message). The
651: * message is printed immediately, but only if the client is being executed
652: * in verbose mode. These messages are primarily intended to ease debugging
653: * authentication problems. The length of the formatted message must not
654: * exceed 1024 bytes. This will automatically call packet_write_wait.
655: */
1.1 deraadt 656:
1.2 provos 657: void
1.14 markus 658: packet_send_debug(const char *fmt,...)
1.1 deraadt 659: {
1.14 markus 660: char buf[1024];
661: va_list args;
662:
663: va_start(args, fmt);
664: vsnprintf(buf, sizeof(buf), fmt, args);
665: va_end(args);
666:
667: packet_start(SSH_MSG_DEBUG);
668: packet_put_string(buf, strlen(buf));
669: packet_send();
670: packet_write_wait();
1.1 deraadt 671: }
672:
1.16 markus 673: /*
674: * Logs the error plus constructs and sends a disconnect packet, closes the
675: * connection, and exits. This function never returns. The error message
676: * should not contain a newline. The length of the formatted message must
677: * not exceed 1024 bytes.
678: */
1.1 deraadt 679:
1.2 provos 680: void
1.14 markus 681: packet_disconnect(const char *fmt,...)
1.1 deraadt 682: {
1.14 markus 683: char buf[1024];
684: va_list args;
685: static int disconnecting = 0;
686: if (disconnecting) /* Guard against recursive invocations. */
687: fatal("packet_disconnect called recursively.");
688: disconnecting = 1;
689:
1.16 markus 690: /*
691: * Format the message. Note that the caller must make sure the
692: * message is of limited size.
693: */
1.14 markus 694: va_start(args, fmt);
695: vsnprintf(buf, sizeof(buf), fmt, args);
696: va_end(args);
697:
698: /* Send the disconnect message to the other side, and wait for it to get sent. */
699: packet_start(SSH_MSG_DISCONNECT);
700: packet_put_string(buf, strlen(buf));
701: packet_send();
702: packet_write_wait();
703:
704: /* Stop listening for connections. */
705: channel_stop_listening();
706:
707: /* Close the connection. */
708: packet_close();
1.1 deraadt 709:
1.14 markus 710: /* Display the error locally and exit. */
1.17 markus 711: log("Disconnecting: %.100s", buf);
712: fatal_cleanup();
1.1 deraadt 713: }
714:
1.16 markus 715: /* Checks if there is any buffered output, and tries to write some of the output. */
1.1 deraadt 716:
1.2 provos 717: void
718: packet_write_poll()
1.1 deraadt 719: {
1.14 markus 720: int len = buffer_len(&output);
721: if (len > 0) {
722: len = write(connection_out, buffer_ptr(&output), len);
723: if (len <= 0) {
724: if (errno == EAGAIN)
725: return;
726: else
727: fatal("Write failed: %.100s", strerror(errno));
728: }
729: buffer_consume(&output, len);
730: }
1.1 deraadt 731: }
732:
1.16 markus 733: /*
734: * Calls packet_write_poll repeatedly until all pending output data has been
735: * written.
736: */
1.1 deraadt 737:
1.2 provos 738: void
739: packet_write_wait()
1.1 deraadt 740: {
1.14 markus 741: packet_write_poll();
742: while (packet_have_data_to_write()) {
743: fd_set set;
744: FD_ZERO(&set);
745: FD_SET(connection_out, &set);
746: select(connection_out + 1, NULL, &set, NULL, NULL);
747: packet_write_poll();
748: }
1.1 deraadt 749: }
750:
751: /* Returns true if there is buffered data to write to the connection. */
752:
1.2 provos 753: int
754: packet_have_data_to_write()
1.1 deraadt 755: {
1.14 markus 756: return buffer_len(&output) != 0;
1.1 deraadt 757: }
758:
759: /* Returns true if there is not too much data to write to the connection. */
760:
1.2 provos 761: int
762: packet_not_very_much_data_to_write()
1.1 deraadt 763: {
1.14 markus 764: if (interactive_mode)
765: return buffer_len(&output) < 16384;
766: else
767: return buffer_len(&output) < 128 * 1024;
1.1 deraadt 768: }
769:
770: /* Informs that the current session is interactive. Sets IP flags for that. */
771:
1.2 provos 772: void
773: packet_set_interactive(int interactive, int keepalives)
1.1 deraadt 774: {
1.14 markus 775: int on = 1;
1.1 deraadt 776:
1.14 markus 777: /* Record that we are in interactive mode. */
778: interactive_mode = interactive;
1.1 deraadt 779:
1.19 markus 780: /* Only set socket options if using a socket. */
781: if (!packet_connection_is_on_socket())
1.14 markus 782: return;
783: if (keepalives) {
784: /* Set keepalives if requested. */
785: if (setsockopt(connection_in, SOL_SOCKET, SO_KEEPALIVE, (void *) &on,
1.19 markus 786: sizeof(on)) < 0)
1.14 markus 787: error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
788: }
1.19 markus 789: /*
790: * IPTOS_LOWDELAY, TCP_NODELAY and IPTOS_THROUGHPUT are IPv4 only
791: */
792: if (!packet_connection_is_ipv4())
793: return;
1.14 markus 794: if (interactive) {
1.16 markus 795: /*
796: * Set IP options for an interactive connection. Use
797: * IPTOS_LOWDELAY and TCP_NODELAY.
798: */
1.14 markus 799: int lowdelay = IPTOS_LOWDELAY;
800: if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, (void *) &lowdelay,
1.19 markus 801: sizeof(lowdelay)) < 0)
1.14 markus 802: error("setsockopt IPTOS_LOWDELAY: %.100s", strerror(errno));
803: if (setsockopt(connection_in, IPPROTO_TCP, TCP_NODELAY, (void *) &on,
1.19 markus 804: sizeof(on)) < 0)
1.14 markus 805: error("setsockopt TCP_NODELAY: %.100s", strerror(errno));
806: } else {
1.16 markus 807: /*
808: * Set IP options for a non-interactive connection. Use
809: * IPTOS_THROUGHPUT.
810: */
1.14 markus 811: int throughput = IPTOS_THROUGHPUT;
812: if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, (void *) &throughput,
1.19 markus 813: sizeof(throughput)) < 0)
1.14 markus 814: error("setsockopt IPTOS_THROUGHPUT: %.100s", strerror(errno));
815: }
1.1 deraadt 816: }
817:
818: /* Returns true if the current connection is interactive. */
819:
1.2 provos 820: int
821: packet_is_interactive()
1.1 deraadt 822: {
1.14 markus 823: return interactive_mode;
1.12 markus 824: }
825:
826: int
827: packet_set_maxsize(int s)
828: {
1.14 markus 829: static int called = 0;
830: if (called) {
831: log("packet_set_maxsize: called twice: old %d new %d", max_packet_size, s);
832: return -1;
833: }
834: if (s < 4 * 1024 || s > 1024 * 1024) {
835: log("packet_set_maxsize: bad size %d", s);
836: return -1;
837: }
838: log("packet_set_maxsize: setting to %d", s);
839: max_packet_size = s;
840: return s;
1.1 deraadt 841: }
![[BACK]](/icons/back.gif){kind=icon}
Return to packet.c CVS log ![[TXT]](/icons/text.gif){kind=icon}
![[DIR]](/icons/dir.gif){kind=icon}
Up to [local] / src / usr.bin / ssh