Annotation of src/usr.bin/ssh/packet.c, Revision 1.10
1.1 deraadt 1: /*
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: */
16:
17: #include "includes.h"
1.10 ! markus 18: RCSID("$Id: packet.c,v 1.9 1999/10/05 01:23:54 dugsong 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:
32: /* This variable contains the file descriptors used for communicating with
33: the other side. connection_in is used for reading; connection_out
34: for writing. These can be the same descriptor, in which case it is
35: assumed to be a socket. */
36: static int connection_in = -1;
37: static int connection_out = -1;
38:
39: /* Cipher type. This value is only used to determine whether to pad the
40: packets with zeroes or random data. */
41: static int cipher_type = SSH_CIPHER_NONE;
42:
43: /* Protocol flags for the remote side. */
44: static unsigned int remote_protocol_flags = 0;
45:
46: /* Encryption context for receiving data. This is only used for decryption. */
47: static CipherContext receive_context;
48: /* Encryption coontext for sending data. This is only used for encryption. */
49: static CipherContext send_context;
50:
51: /* Buffer for raw input data from the socket. */
52: static Buffer input;
53:
54: /* Buffer for raw output data going to the socket. */
55: static Buffer output;
56:
57: /* Buffer for the partial outgoing packet being constructed. */
58: static Buffer outgoing_packet;
59:
60: /* Buffer for the incoming packet currently being processed. */
61: static Buffer incoming_packet;
62:
63: /* Scratch buffer for packet compression/decompression. */
64: static Buffer compression_buffer;
65:
66: /* Flag indicating whether packet compression/decompression is enabled. */
67: static int packet_compression = 0;
68:
69: /* Flag indicating whether this module has been initialized. */
70: static int initialized = 0;
71:
72: /* Set to true if the connection is interactive. */
73: static int interactive_mode = 0;
74:
75: /* Sets the descriptors used for communication. Disables encryption until
76: packet_set_encryption_key is called. */
77:
1.2 provos 78: void
79: packet_set_connection(int fd_in, int fd_out)
1.1 deraadt 80: {
81: connection_in = fd_in;
82: connection_out = fd_out;
83: cipher_type = SSH_CIPHER_NONE;
84: cipher_set_key(&send_context, SSH_CIPHER_NONE, (unsigned char *)"", 0, 1);
85: cipher_set_key(&receive_context, SSH_CIPHER_NONE, (unsigned char *)"", 0, 0);
86: if (!initialized)
87: {
88: initialized = 1;
89: buffer_init(&input);
90: buffer_init(&output);
91: buffer_init(&outgoing_packet);
92: buffer_init(&incoming_packet);
93: }
94:
95: /* Kludge: arrange the close function to be called from fatal(). */
96: fatal_add_cleanup((void (*)(void *))packet_close, NULL);
97: }
98:
99: /* Sets the connection into non-blocking mode. */
100:
1.2 provos 101: void
102: packet_set_nonblocking()
1.1 deraadt 103: {
104: /* Set the socket into non-blocking mode. */
105: if (fcntl(connection_in, F_SETFL, O_NONBLOCK) < 0)
106: error("fcntl O_NONBLOCK: %.100s", strerror(errno));
107:
108: if (connection_out != connection_in)
109: {
110: if (fcntl(connection_out, F_SETFL, O_NONBLOCK) < 0)
111: error("fcntl O_NONBLOCK: %.100s", strerror(errno));
112: }
113: }
114:
115: /* Returns the socket used for reading. */
116:
1.2 provos 117: int
118: packet_get_connection_in()
1.1 deraadt 119: {
120: return connection_in;
121: }
122:
123: /* Returns the descriptor used for writing. */
124:
1.2 provos 125: int
126: packet_get_connection_out()
1.1 deraadt 127: {
128: return connection_out;
129: }
130:
131: /* Closes the connection and clears and frees internal data structures. */
132:
1.2 provos 133: void
134: packet_close()
1.1 deraadt 135: {
136: if (!initialized)
137: return;
138: initialized = 0;
139: if (connection_in == connection_out)
140: {
1.8 deraadt 141: shutdown(connection_out, SHUT_RDWR);
1.1 deraadt 142: close(connection_out);
143: }
144: else
145: {
146: close(connection_in);
147: close(connection_out);
148: }
149: buffer_free(&input);
150: buffer_free(&output);
151: buffer_free(&outgoing_packet);
152: buffer_free(&incoming_packet);
153: if (packet_compression)
154: {
155: buffer_free(&compression_buffer);
156: buffer_compress_uninit();
157: }
158: }
159:
160: /* Sets remote side protocol flags. */
161:
1.2 provos 162: void
163: packet_set_protocol_flags(unsigned int protocol_flags)
1.1 deraadt 164: {
165: remote_protocol_flags = protocol_flags;
166: channel_set_options((protocol_flags & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) != 0);
167: }
168:
169: /* Returns the remote protocol flags set earlier by the above function. */
170:
1.2 provos 171: unsigned int
172: packet_get_protocol_flags()
1.1 deraadt 173: {
174: return remote_protocol_flags;
175: }
176:
177: /* Starts packet compression from the next packet on in both directions.
178: Level is compression level 1 (fastest) - 9 (slow, best) as in gzip. */
179:
1.2 provos 180: void
181: packet_start_compression(int level)
1.1 deraadt 182: {
183: if (packet_compression)
184: fatal("Compression already enabled.");
185: packet_compression = 1;
186: buffer_init(&compression_buffer);
187: buffer_compress_init(level);
188: }
189:
190: /* Encrypts the given number of bytes, copying from src to dest.
191: bytes is known to be a multiple of 8. */
192:
1.2 provos 193: void
194: packet_encrypt(CipherContext *cc, void *dest, void *src,
195: unsigned int bytes)
1.1 deraadt 196: {
197: cipher_encrypt(cc, dest, src, bytes);
198: }
199:
200: /* Decrypts the given number of bytes, copying from src to dest.
201: bytes is known to be a multiple of 8. */
202:
1.2 provos 203: void
204: packet_decrypt(CipherContext *cc, void *dest, void *src,
205: unsigned int bytes)
1.1 deraadt 206: {
1.9 dugsong 207: int i;
208:
1.10 ! markus 209: if ((bytes % 8) != 0)
! 210: fatal("packet_decrypt: bad ciphertext length %d", bytes);
1.9 dugsong 211:
212: /*
213: Cryptographic attack detector for ssh - Modifications for packet.c
214: (C)1998 CORE-SDI, Buenos Aires Argentina
215: Ariel Futoransky(futo@core-sdi.com)
216: */
217: switch (cc->type)
218: {
219: case SSH_CIPHER_NONE:
220: i = DEATTACK_OK;
221: break;
222: default:
223: i = detect_attack(src, bytes, NULL);
224: break;
225: }
226:
227: if (i == DEATTACK_DETECTED)
228: packet_disconnect("crc32 compensation attack: network attack detected");
229:
1.1 deraadt 230: cipher_decrypt(cc, dest, src, bytes);
231: }
232:
233: /* Causes any further packets to be encrypted using the given key. The same
234: key is used for both sending and reception. However, both directions
235: are encrypted independently of each other. */
236:
1.2 provos 237: void
238: packet_set_encryption_key(const unsigned char *key, unsigned int keylen,
239: int cipher, int is_client)
1.1 deraadt 240: {
241: cipher_type = cipher;
242: if (cipher == SSH_CIPHER_RC4)
243: {
244: if (is_client)
245: { /* In client: use first half for receiving, second for sending. */
246: cipher_set_key(&receive_context, cipher, key, keylen / 2, 0);
247: cipher_set_key(&send_context, cipher, key + keylen / 2,
248: keylen / 2, 1);
249: }
250: else
251: { /* In server: use first half for sending, second for receiving. */
252: cipher_set_key(&receive_context, cipher, key + keylen / 2,
253: keylen / 2, 0);
254: cipher_set_key(&send_context, cipher, key, keylen / 2, 1);
255: }
256: }
257: else
258: {
259: /* All other ciphers use the same key in both directions for now. */
260: cipher_set_key(&receive_context, cipher, key, keylen, 0);
261: cipher_set_key(&send_context, cipher, key, keylen, 1);
262: }
263: }
264:
265: /* Starts constructing a packet to send. */
266:
1.2 provos 267: void
268: packet_start(int type)
1.1 deraadt 269: {
270: char buf[9];
271:
272: buffer_clear(&outgoing_packet);
273: memset(buf, 0, 8);
274: buf[8] = type;
275: buffer_append(&outgoing_packet, buf, 9);
276: }
277:
278: /* Appends a character to the packet data. */
279:
1.2 provos 280: void
281: packet_put_char(int value)
1.1 deraadt 282: {
283: char ch = value;
284: buffer_append(&outgoing_packet, &ch, 1);
285: }
286:
287: /* Appends an integer to the packet data. */
288:
1.2 provos 289: void
290: packet_put_int(unsigned int value)
1.1 deraadt 291: {
292: buffer_put_int(&outgoing_packet, value);
293: }
294:
295: /* Appends a string to packet data. */
296:
1.2 provos 297: void
298: packet_put_string(const char *buf, unsigned int len)
1.1 deraadt 299: {
300: buffer_put_string(&outgoing_packet, buf, len);
301: }
302:
303: /* Appends an arbitrary precision integer to packet data. */
304:
1.2 provos 305: void
306: packet_put_bignum(BIGNUM *value)
1.1 deraadt 307: {
1.2 provos 308: buffer_put_bignum(&outgoing_packet, value);
1.1 deraadt 309: }
310:
311: /* Finalizes and sends the packet. If the encryption key has been set,
312: encrypts the packet before sending. */
313:
1.2 provos 314: void
315: packet_send()
1.1 deraadt 316: {
317: char buf[8], *cp;
318: int i, padding, len;
1.7 deraadt 319: unsigned int checksum;
1.3 dugsong 320: u_int32_t rand = 0;
1.1 deraadt 321:
322: /* If using packet compression, compress the payload of the outgoing
323: packet. */
324: if (packet_compression)
325: {
326: buffer_clear(&compression_buffer);
327: buffer_consume(&outgoing_packet, 8); /* Skip padding. */
328: buffer_append(&compression_buffer, "\0\0\0\0\0\0\0\0", 8); /* padding */
329: buffer_compress(&outgoing_packet, &compression_buffer);
330: buffer_clear(&outgoing_packet);
331: buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer),
332: buffer_len(&compression_buffer));
333: }
334:
335: /* Compute packet length without padding (add checksum, remove padding). */
336: len = buffer_len(&outgoing_packet) + 4 - 8;
337:
338: /* Insert padding. */
339: padding = 8 - len % 8;
340: if (cipher_type != SSH_CIPHER_NONE)
341: {
342: cp = buffer_ptr(&outgoing_packet);
1.2 provos 343: for (i = 0; i < padding; i++) {
344: if (i % 4 == 0)
345: rand = arc4random();
346: cp[7 - i] = rand & 0xff;
347: rand >>= 8;
348: }
1.1 deraadt 349: }
350: buffer_consume(&outgoing_packet, 8 - padding);
351:
352: /* Add check bytes. */
353: checksum = crc32((unsigned char *)buffer_ptr(&outgoing_packet),
354: buffer_len(&outgoing_packet));
355: PUT_32BIT(buf, checksum);
356: buffer_append(&outgoing_packet, buf, 4);
357:
358: #ifdef PACKET_DEBUG
359: fprintf(stderr, "packet_send plain: ");
360: buffer_dump(&outgoing_packet);
361: #endif
362:
363: /* Append to output. */
364: PUT_32BIT(buf, len);
365: buffer_append(&output, buf, 4);
366: buffer_append_space(&output, &cp, buffer_len(&outgoing_packet));
367: packet_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet),
368: buffer_len(&outgoing_packet));
369:
370: #ifdef PACKET_DEBUG
371: fprintf(stderr, "encrypted: "); buffer_dump(&output);
372: #endif
373:
374: buffer_clear(&outgoing_packet);
375:
376: /* Note that the packet is now only buffered in output. It won\'t be
377: actually sent until packet_write_wait or packet_write_poll is called. */
378: }
379:
380: /* Waits until a packet has been received, and returns its type. Note that
381: no other data is processed until this returns, so this function should
382: not be used during the interactive session. */
383:
1.2 provos 384: int
385: packet_read(int *payload_len_ptr)
1.1 deraadt 386: {
387: int type, len;
388: fd_set set;
389: char buf[8192];
390:
391: /* Since we are blocking, ensure that all written packets have been sent. */
392: packet_write_wait();
393:
394: /* Stay in the loop until we have received a complete packet. */
395: for (;;)
396: {
397: /* Try to read a packet from the buffer. */
398: type = packet_read_poll(payload_len_ptr);
399: if (type == SSH_SMSG_SUCCESS
400: || type == SSH_SMSG_FAILURE
401: || type == SSH_CMSG_EOF
402: || type == SSH_CMSG_EXIT_CONFIRMATION)
403: packet_integrity_check(*payload_len_ptr, 0, type);
404: /* If we got a packet, return it. */
405: if (type != SSH_MSG_NONE)
406: return type;
407: /* Otherwise, wait for some data to arrive, add it to the buffer,
408: and try again. */
409: FD_ZERO(&set);
410: FD_SET(connection_in, &set);
411: /* Wait for some data to arrive. */
412: select(connection_in + 1, &set, NULL, NULL, NULL);
413: /* Read data from the socket. */
414: len = read(connection_in, buf, sizeof(buf));
415: if (len == 0)
416: fatal("Connection closed by remote host.");
417: if (len < 0)
418: fatal("Read from socket failed: %.100s", strerror(errno));
419: /* Append it to the buffer. */
420: packet_process_incoming(buf, len);
421: }
422: /*NOTREACHED*/
423: }
424:
425: /* Waits until a packet has been received, verifies that its type matches
426: that given, and gives a fatal error and exits if there is a mismatch. */
427:
1.2 provos 428: void
429: packet_read_expect(int *payload_len_ptr, int expected_type)
1.1 deraadt 430: {
431: int type;
432:
433: type = packet_read(payload_len_ptr);
434: if (type != expected_type)
435: packet_disconnect("Protocol error: expected packet type %d, got %d",
436: expected_type, type);
437: }
438:
439: /* Checks if a full packet is available in the data received so far via
440: packet_process_incoming. If so, reads the packet; otherwise returns
441: SSH_MSG_NONE. This does not wait for data from the connection.
442:
443: SSH_MSG_DISCONNECT is handled specially here. Also,
444: SSH_MSG_IGNORE messages are skipped by this function and are never returned
445: to higher levels.
446:
447: The returned payload_len does include space consumed by:
448: Packet length
449: Padding
450: Packet type
451: Check bytes
452:
453:
454: */
455:
1.2 provos 456: int
457: packet_read_poll(int *payload_len_ptr)
1.1 deraadt 458: {
459: unsigned int len, padded_len;
460: unsigned char *ucp;
461: char buf[8], *cp;
1.7 deraadt 462: unsigned int checksum, stored_checksum;
1.1 deraadt 463:
464: restart:
465:
466: /* Check if input size is less than minimum packet size. */
467: if (buffer_len(&input) < 4 + 8)
468: return SSH_MSG_NONE;
469: /* Get length of incoming packet. */
470: ucp = (unsigned char *)buffer_ptr(&input);
471: len = GET_32BIT(ucp);
472: if (len < 1 + 2 + 2 || len > 256*1024)
473: packet_disconnect("Bad packet length %d.", len);
474: padded_len = (len + 8) & ~7;
475:
476: /* Check if the packet has been entirely received. */
477: if (buffer_len(&input) < 4 + padded_len)
478: return SSH_MSG_NONE;
479:
480: /* The entire packet is in buffer. */
481:
482: /* Consume packet length. */
483: buffer_consume(&input, 4);
484:
485: /* Copy data to incoming_packet. */
486: buffer_clear(&incoming_packet);
487: buffer_append_space(&incoming_packet, &cp, padded_len);
488: packet_decrypt(&receive_context, cp, buffer_ptr(&input), padded_len);
489: buffer_consume(&input, padded_len);
490:
491: #ifdef PACKET_DEBUG
492: fprintf(stderr, "read_poll plain: "); buffer_dump(&incoming_packet);
493: #endif
494:
495: /* Compute packet checksum. */
496: checksum = crc32((unsigned char *)buffer_ptr(&incoming_packet),
497: buffer_len(&incoming_packet) - 4);
498:
499: /* Skip padding. */
500: buffer_consume(&incoming_packet, 8 - len % 8);
501:
502: /* Test check bytes. */
1.10 ! markus 503:
! 504: if (len != buffer_len(&incoming_packet))
! 505: packet_disconnect("packet_read_poll: len %d != buffer_len %d.",
! 506: len, buffer_len(&incoming_packet));
! 507:
1.1 deraadt 508: ucp = (unsigned char *)buffer_ptr(&incoming_packet) + len - 4;
509: stored_checksum = GET_32BIT(ucp);
510: if (checksum != stored_checksum)
511: packet_disconnect("Corrupted check bytes on input.");
512: buffer_consume_end(&incoming_packet, 4);
513:
514: /* If using packet compression, decompress the packet. */
515: if (packet_compression)
516: {
517: buffer_clear(&compression_buffer);
518: buffer_uncompress(&incoming_packet, &compression_buffer);
519: buffer_clear(&incoming_packet);
520: buffer_append(&incoming_packet, buffer_ptr(&compression_buffer),
521: buffer_len(&compression_buffer));
522: }
523:
524: /* Get packet type. */
525: buffer_get(&incoming_packet, &buf[0], 1);
526:
527: /* Return length of payload (without type field). */
528: *payload_len_ptr = buffer_len(&incoming_packet);
529:
530: /* Handle disconnect message. */
531: if ((unsigned char)buf[0] == SSH_MSG_DISCONNECT)
532: fatal("%.900s", packet_get_string(NULL));
533:
534: /* Ignore ignore messages. */
535: if ((unsigned char)buf[0] == SSH_MSG_IGNORE)
536: goto restart;
537:
538: /* Send debug messages as debugging output. */
539: if ((unsigned char)buf[0] == SSH_MSG_DEBUG)
540: {
541: debug("Remote: %.900s", packet_get_string(NULL));
542: goto restart;
543: }
544:
545: /* Return type. */
546: return (unsigned char)buf[0];
547: }
548:
549: /* Buffers the given amount of input characters. This is intended to be
550: used together with packet_read_poll. */
551:
1.2 provos 552: void
553: packet_process_incoming(const char *buf, unsigned int len)
1.1 deraadt 554: {
555: buffer_append(&input, buf, len);
556: }
557:
558: /* Returns a character from the packet. */
559:
1.2 provos 560: unsigned int
561: packet_get_char()
1.1 deraadt 562: {
563: char ch;
564: buffer_get(&incoming_packet, &ch, 1);
565: return (unsigned char)ch;
566: }
567:
568: /* Returns an integer from the packet data. */
569:
1.2 provos 570: unsigned int
571: packet_get_int()
1.1 deraadt 572: {
573: return buffer_get_int(&incoming_packet);
574: }
575:
576: /* Returns an arbitrary precision integer from the packet data. The integer
577: must have been initialized before this call. */
578:
1.2 provos 579: void
580: packet_get_bignum(BIGNUM *value, int *length_ptr)
1.1 deraadt 581: {
1.2 provos 582: *length_ptr = buffer_get_bignum(&incoming_packet, value);
1.1 deraadt 583: }
584:
585: /* Returns a string from the packet data. The string is allocated using
586: xmalloc; it is the responsibility of the calling program to free it when
587: no longer needed. The length_ptr argument may be NULL, or point to an
588: integer into which the length of the string is stored. */
589:
1.2 provos 590: char
591: *packet_get_string(unsigned int *length_ptr)
1.1 deraadt 592: {
593: return buffer_get_string(&incoming_packet, length_ptr);
594: }
595:
596: /* Sends a diagnostic message from the server to the client. This message
597: can be sent at any time (but not while constructing another message).
598: The message is printed immediately, but only if the client is being
599: executed in verbose mode. These messages are primarily intended to
600: ease debugging authentication problems. The length of the formatted
601: message must not exceed 1024 bytes. This will automatically call
602: packet_write_wait. */
603:
1.2 provos 604: void
605: packet_send_debug(const char *fmt, ...)
1.1 deraadt 606: {
607: char buf[1024];
608: va_list args;
609:
610: va_start(args, fmt);
611: vsnprintf(buf, sizeof(buf), fmt, args);
612: va_end(args);
613:
614: packet_start(SSH_MSG_DEBUG);
615: packet_put_string(buf, strlen(buf));
616: packet_send();
617: packet_write_wait();
618: }
619:
620: /* Logs the error plus constructs and sends a disconnect
621: packet, closes the connection, and exits. This function never returns.
622: The error message should not contain a newline. The length of the
623: formatted message must not exceed 1024 bytes. */
624:
1.2 provos 625: void
626: packet_disconnect(const char *fmt, ...)
1.1 deraadt 627: {
628: char buf[1024];
629: va_list args;
630: static int disconnecting = 0;
631: if (disconnecting) /* Guard against recursive invocations. */
632: fatal("packet_disconnect called recursively.");
633: disconnecting = 1;
634:
635: /* Format the message. Note that the caller must make sure the message
636: is of limited size. */
637: va_start(args, fmt);
638: vsnprintf(buf, sizeof(buf), fmt, args);
639: va_end(args);
640:
641: /* Send the disconnect message to the other side, and wait for it to get
642: sent. */
643: packet_start(SSH_MSG_DISCONNECT);
644: packet_put_string(buf, strlen(buf));
645: packet_send();
646: packet_write_wait();
647:
648: /* Stop listening for connections. */
649: channel_stop_listening();
650:
651: /* Close the connection. */
652: packet_close();
653:
654: /* Display the error locally and exit. */
655: fatal("Local: %.100s", buf);
656: }
657:
658: /* Checks if there is any buffered output, and tries to write some of the
659: output. */
660:
1.2 provos 661: void
662: packet_write_poll()
1.1 deraadt 663: {
664: int len = buffer_len(&output);
665: if (len > 0)
666: {
667: len = write(connection_out, buffer_ptr(&output), len);
1.2 provos 668: if (len <= 0) {
1.1 deraadt 669: if (errno == EAGAIN)
670: return;
671: else
672: fatal("Write failed: %.100s", strerror(errno));
1.2 provos 673: }
1.1 deraadt 674: buffer_consume(&output, len);
675: }
676: }
677:
678: /* Calls packet_write_poll repeatedly until all pending output data has
679: been written. */
680:
1.2 provos 681: void
682: packet_write_wait()
1.1 deraadt 683: {
684: packet_write_poll();
685: while (packet_have_data_to_write())
686: {
687: fd_set set;
688: FD_ZERO(&set);
689: FD_SET(connection_out, &set);
690: select(connection_out + 1, NULL, &set, NULL, NULL);
691: packet_write_poll();
692: }
693: }
694:
695: /* Returns true if there is buffered data to write to the connection. */
696:
1.2 provos 697: int
698: packet_have_data_to_write()
1.1 deraadt 699: {
700: return buffer_len(&output) != 0;
701: }
702:
703: /* Returns true if there is not too much data to write to the connection. */
704:
1.2 provos 705: int
706: packet_not_very_much_data_to_write()
1.1 deraadt 707: {
708: if (interactive_mode)
709: return buffer_len(&output) < 16384;
710: else
711: return buffer_len(&output) < 128*1024;
712: }
713:
714: /* Informs that the current session is interactive. Sets IP flags for that. */
715:
1.2 provos 716: void
717: packet_set_interactive(int interactive, int keepalives)
1.1 deraadt 718: {
719: int on = 1;
720:
721: /* Record that we are in interactive mode. */
722: interactive_mode = interactive;
723:
724: /* Only set socket options if using a socket (as indicated by the descriptors
725: being the same). */
726: if (connection_in != connection_out)
727: return;
728:
729: if (keepalives)
730: {
731: /* Set keepalives if requested. */
732: if (setsockopt(connection_in, SOL_SOCKET, SO_KEEPALIVE, (void *)&on,
733: sizeof(on)) < 0)
734: error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
735: }
736:
737: if (interactive)
738: {
739: /* Set IP options for an interactive connection. Use IPTOS_LOWDELAY
740: and TCP_NODELAY. */
741: int lowdelay = IPTOS_LOWDELAY;
742: if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, (void *)&lowdelay,
743: sizeof(lowdelay)) < 0)
744: error("setsockopt IPTOS_LOWDELAY: %.100s", strerror(errno));
745: if (setsockopt(connection_in, IPPROTO_TCP, TCP_NODELAY, (void *)&on,
746: sizeof(on)) < 0)
747: error("setsockopt TCP_NODELAY: %.100s", strerror(errno));
748: }
749: else
750: {
751: /* Set IP options for a non-interactive connection. Use
752: IPTOS_THROUGHPUT. */
753: int throughput = IPTOS_THROUGHPUT;
754: if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, (void *)&throughput,
755: sizeof(throughput)) < 0)
756: error("setsockopt IPTOS_THROUGHPUT: %.100s", strerror(errno));
757: }
758: }
759:
760: /* Returns true if the current connection is interactive. */
761:
1.2 provos 762: int
763: packet_is_interactive()
1.1 deraadt 764: {
765: return interactive_mode;
766: }
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