Annotation of src/usr.bin/ssh/packet.c, Revision 1.11
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"
1.11 ! markus 18: RCSID("$Id: packet.c,v 1.10 1999/11/02 19:42:36 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:
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,
1.11 ! markus 239: int cipher)
1.1 deraadt 240: {
1.11 ! markus 241: /* All other ciphers use the same key in both directions for now. */
! 242: cipher_set_key(&receive_context, cipher, key, keylen, 0);
! 243: cipher_set_key(&send_context, cipher, key, keylen, 1);
1.1 deraadt 244: }
245:
246: /* Starts constructing a packet to send. */
247:
1.2 provos 248: void
249: packet_start(int type)
1.1 deraadt 250: {
251: char buf[9];
252:
253: buffer_clear(&outgoing_packet);
254: memset(buf, 0, 8);
255: buf[8] = type;
256: buffer_append(&outgoing_packet, buf, 9);
257: }
258:
259: /* Appends a character to the packet data. */
260:
1.2 provos 261: void
262: packet_put_char(int value)
1.1 deraadt 263: {
264: char ch = value;
265: buffer_append(&outgoing_packet, &ch, 1);
266: }
267:
268: /* Appends an integer to the packet data. */
269:
1.2 provos 270: void
271: packet_put_int(unsigned int value)
1.1 deraadt 272: {
273: buffer_put_int(&outgoing_packet, value);
274: }
275:
276: /* Appends a string to packet data. */
277:
1.2 provos 278: void
279: packet_put_string(const char *buf, unsigned int len)
1.1 deraadt 280: {
281: buffer_put_string(&outgoing_packet, buf, len);
282: }
283:
284: /* Appends an arbitrary precision integer to packet data. */
285:
1.2 provos 286: void
287: packet_put_bignum(BIGNUM *value)
1.1 deraadt 288: {
1.2 provos 289: buffer_put_bignum(&outgoing_packet, value);
1.1 deraadt 290: }
291:
292: /* Finalizes and sends the packet. If the encryption key has been set,
293: encrypts the packet before sending. */
294:
1.2 provos 295: void
296: packet_send()
1.1 deraadt 297: {
298: char buf[8], *cp;
299: int i, padding, len;
1.7 deraadt 300: unsigned int checksum;
1.3 dugsong 301: u_int32_t rand = 0;
1.1 deraadt 302:
303: /* If using packet compression, compress the payload of the outgoing
304: packet. */
305: if (packet_compression)
306: {
307: buffer_clear(&compression_buffer);
308: buffer_consume(&outgoing_packet, 8); /* Skip padding. */
309: buffer_append(&compression_buffer, "\0\0\0\0\0\0\0\0", 8); /* padding */
310: buffer_compress(&outgoing_packet, &compression_buffer);
311: buffer_clear(&outgoing_packet);
312: buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer),
313: buffer_len(&compression_buffer));
314: }
315:
316: /* Compute packet length without padding (add checksum, remove padding). */
317: len = buffer_len(&outgoing_packet) + 4 - 8;
318:
319: /* Insert padding. */
320: padding = 8 - len % 8;
321: if (cipher_type != SSH_CIPHER_NONE)
322: {
323: cp = buffer_ptr(&outgoing_packet);
1.2 provos 324: for (i = 0; i < padding; i++) {
325: if (i % 4 == 0)
326: rand = arc4random();
327: cp[7 - i] = rand & 0xff;
328: rand >>= 8;
329: }
1.1 deraadt 330: }
331: buffer_consume(&outgoing_packet, 8 - padding);
332:
333: /* Add check bytes. */
334: checksum = crc32((unsigned char *)buffer_ptr(&outgoing_packet),
335: buffer_len(&outgoing_packet));
336: PUT_32BIT(buf, checksum);
337: buffer_append(&outgoing_packet, buf, 4);
338:
339: #ifdef PACKET_DEBUG
340: fprintf(stderr, "packet_send plain: ");
341: buffer_dump(&outgoing_packet);
342: #endif
343:
344: /* Append to output. */
345: PUT_32BIT(buf, len);
346: buffer_append(&output, buf, 4);
347: buffer_append_space(&output, &cp, buffer_len(&outgoing_packet));
348: packet_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet),
349: buffer_len(&outgoing_packet));
350:
351: #ifdef PACKET_DEBUG
352: fprintf(stderr, "encrypted: "); buffer_dump(&output);
353: #endif
354:
355: buffer_clear(&outgoing_packet);
356:
357: /* Note that the packet is now only buffered in output. It won\'t be
358: actually sent until packet_write_wait or packet_write_poll is called. */
359: }
360:
361: /* Waits until a packet has been received, and returns its type. Note that
362: no other data is processed until this returns, so this function should
363: not be used during the interactive session. */
364:
1.2 provos 365: int
366: packet_read(int *payload_len_ptr)
1.1 deraadt 367: {
368: int type, len;
369: fd_set set;
370: char buf[8192];
371:
372: /* Since we are blocking, ensure that all written packets have been sent. */
373: packet_write_wait();
374:
375: /* Stay in the loop until we have received a complete packet. */
376: for (;;)
377: {
378: /* Try to read a packet from the buffer. */
379: type = packet_read_poll(payload_len_ptr);
380: if (type == SSH_SMSG_SUCCESS
381: || type == SSH_SMSG_FAILURE
382: || type == SSH_CMSG_EOF
383: || type == SSH_CMSG_EXIT_CONFIRMATION)
384: packet_integrity_check(*payload_len_ptr, 0, type);
385: /* If we got a packet, return it. */
386: if (type != SSH_MSG_NONE)
387: return type;
388: /* Otherwise, wait for some data to arrive, add it to the buffer,
389: and try again. */
390: FD_ZERO(&set);
391: FD_SET(connection_in, &set);
392: /* Wait for some data to arrive. */
393: select(connection_in + 1, &set, NULL, NULL, NULL);
394: /* Read data from the socket. */
395: len = read(connection_in, buf, sizeof(buf));
396: if (len == 0)
397: fatal("Connection closed by remote host.");
398: if (len < 0)
399: fatal("Read from socket failed: %.100s", strerror(errno));
400: /* Append it to the buffer. */
401: packet_process_incoming(buf, len);
402: }
403: /*NOTREACHED*/
404: }
405:
406: /* Waits until a packet has been received, verifies that its type matches
407: that given, and gives a fatal error and exits if there is a mismatch. */
408:
1.2 provos 409: void
410: packet_read_expect(int *payload_len_ptr, int expected_type)
1.1 deraadt 411: {
412: int type;
413:
414: type = packet_read(payload_len_ptr);
415: if (type != expected_type)
416: packet_disconnect("Protocol error: expected packet type %d, got %d",
417: expected_type, type);
418: }
419:
420: /* Checks if a full packet is available in the data received so far via
421: packet_process_incoming. If so, reads the packet; otherwise returns
422: SSH_MSG_NONE. This does not wait for data from the connection.
423:
424: SSH_MSG_DISCONNECT is handled specially here. Also,
425: SSH_MSG_IGNORE messages are skipped by this function and are never returned
426: to higher levels.
427:
428: The returned payload_len does include space consumed by:
429: Packet length
430: Padding
431: Packet type
432: Check bytes
433:
434:
435: */
436:
1.2 provos 437: int
438: packet_read_poll(int *payload_len_ptr)
1.1 deraadt 439: {
440: unsigned int len, padded_len;
441: unsigned char *ucp;
442: char buf[8], *cp;
1.7 deraadt 443: unsigned int checksum, stored_checksum;
1.1 deraadt 444:
445: restart:
446:
447: /* Check if input size is less than minimum packet size. */
448: if (buffer_len(&input) < 4 + 8)
449: return SSH_MSG_NONE;
450: /* Get length of incoming packet. */
451: ucp = (unsigned char *)buffer_ptr(&input);
452: len = GET_32BIT(ucp);
453: if (len < 1 + 2 + 2 || len > 256*1024)
454: packet_disconnect("Bad packet length %d.", len);
455: padded_len = (len + 8) & ~7;
456:
457: /* Check if the packet has been entirely received. */
458: if (buffer_len(&input) < 4 + padded_len)
459: return SSH_MSG_NONE;
460:
461: /* The entire packet is in buffer. */
462:
463: /* Consume packet length. */
464: buffer_consume(&input, 4);
465:
466: /* Copy data to incoming_packet. */
467: buffer_clear(&incoming_packet);
468: buffer_append_space(&incoming_packet, &cp, padded_len);
469: packet_decrypt(&receive_context, cp, buffer_ptr(&input), padded_len);
470: buffer_consume(&input, padded_len);
471:
472: #ifdef PACKET_DEBUG
473: fprintf(stderr, "read_poll plain: "); buffer_dump(&incoming_packet);
474: #endif
475:
476: /* Compute packet checksum. */
477: checksum = crc32((unsigned char *)buffer_ptr(&incoming_packet),
478: buffer_len(&incoming_packet) - 4);
479:
480: /* Skip padding. */
481: buffer_consume(&incoming_packet, 8 - len % 8);
482:
483: /* Test check bytes. */
1.10 markus 484:
485: if (len != buffer_len(&incoming_packet))
486: packet_disconnect("packet_read_poll: len %d != buffer_len %d.",
487: len, buffer_len(&incoming_packet));
488:
1.1 deraadt 489: ucp = (unsigned char *)buffer_ptr(&incoming_packet) + len - 4;
490: stored_checksum = GET_32BIT(ucp);
491: if (checksum != stored_checksum)
492: packet_disconnect("Corrupted check bytes on input.");
493: buffer_consume_end(&incoming_packet, 4);
494:
495: /* If using packet compression, decompress the packet. */
496: if (packet_compression)
497: {
498: buffer_clear(&compression_buffer);
499: buffer_uncompress(&incoming_packet, &compression_buffer);
500: buffer_clear(&incoming_packet);
501: buffer_append(&incoming_packet, buffer_ptr(&compression_buffer),
502: buffer_len(&compression_buffer));
503: }
504:
505: /* Get packet type. */
506: buffer_get(&incoming_packet, &buf[0], 1);
507:
508: /* Return length of payload (without type field). */
509: *payload_len_ptr = buffer_len(&incoming_packet);
510:
511: /* Handle disconnect message. */
512: if ((unsigned char)buf[0] == SSH_MSG_DISCONNECT)
513: fatal("%.900s", packet_get_string(NULL));
514:
515: /* Ignore ignore messages. */
516: if ((unsigned char)buf[0] == SSH_MSG_IGNORE)
517: goto restart;
518:
519: /* Send debug messages as debugging output. */
520: if ((unsigned char)buf[0] == SSH_MSG_DEBUG)
521: {
522: debug("Remote: %.900s", packet_get_string(NULL));
523: goto restart;
524: }
525:
526: /* Return type. */
527: return (unsigned char)buf[0];
528: }
529:
530: /* Buffers the given amount of input characters. This is intended to be
531: used together with packet_read_poll. */
532:
1.2 provos 533: void
534: packet_process_incoming(const char *buf, unsigned int len)
1.1 deraadt 535: {
536: buffer_append(&input, buf, len);
537: }
538:
539: /* Returns a character from the packet. */
540:
1.2 provos 541: unsigned int
542: packet_get_char()
1.1 deraadt 543: {
544: char ch;
545: buffer_get(&incoming_packet, &ch, 1);
546: return (unsigned char)ch;
547: }
548:
549: /* Returns an integer from the packet data. */
550:
1.2 provos 551: unsigned int
552: packet_get_int()
1.1 deraadt 553: {
554: return buffer_get_int(&incoming_packet);
555: }
556:
557: /* Returns an arbitrary precision integer from the packet data. The integer
558: must have been initialized before this call. */
559:
1.2 provos 560: void
561: packet_get_bignum(BIGNUM *value, int *length_ptr)
1.1 deraadt 562: {
1.2 provos 563: *length_ptr = buffer_get_bignum(&incoming_packet, value);
1.1 deraadt 564: }
565:
566: /* Returns a string from the packet data. The string is allocated using
567: xmalloc; it is the responsibility of the calling program to free it when
568: no longer needed. The length_ptr argument may be NULL, or point to an
569: integer into which the length of the string is stored. */
570:
1.2 provos 571: char
572: *packet_get_string(unsigned int *length_ptr)
1.1 deraadt 573: {
574: return buffer_get_string(&incoming_packet, length_ptr);
575: }
576:
577: /* Sends a diagnostic message from the server to the client. This message
578: can be sent at any time (but not while constructing another message).
579: The message is printed immediately, but only if the client is being
580: executed in verbose mode. These messages are primarily intended to
581: ease debugging authentication problems. The length of the formatted
582: message must not exceed 1024 bytes. This will automatically call
583: packet_write_wait. */
584:
1.2 provos 585: void
586: packet_send_debug(const char *fmt, ...)
1.1 deraadt 587: {
588: char buf[1024];
589: va_list args;
590:
591: va_start(args, fmt);
592: vsnprintf(buf, sizeof(buf), fmt, args);
593: va_end(args);
594:
595: packet_start(SSH_MSG_DEBUG);
596: packet_put_string(buf, strlen(buf));
597: packet_send();
598: packet_write_wait();
599: }
600:
601: /* Logs the error plus constructs and sends a disconnect
602: packet, closes the connection, and exits. This function never returns.
603: The error message should not contain a newline. The length of the
604: formatted message must not exceed 1024 bytes. */
605:
1.2 provos 606: void
607: packet_disconnect(const char *fmt, ...)
1.1 deraadt 608: {
609: char buf[1024];
610: va_list args;
611: static int disconnecting = 0;
612: if (disconnecting) /* Guard against recursive invocations. */
613: fatal("packet_disconnect called recursively.");
614: disconnecting = 1;
615:
616: /* Format the message. Note that the caller must make sure the message
617: is of limited size. */
618: va_start(args, fmt);
619: vsnprintf(buf, sizeof(buf), fmt, args);
620: va_end(args);
621:
622: /* Send the disconnect message to the other side, and wait for it to get
623: sent. */
624: packet_start(SSH_MSG_DISCONNECT);
625: packet_put_string(buf, strlen(buf));
626: packet_send();
627: packet_write_wait();
628:
629: /* Stop listening for connections. */
630: channel_stop_listening();
631:
632: /* Close the connection. */
633: packet_close();
634:
635: /* Display the error locally and exit. */
636: fatal("Local: %.100s", buf);
637: }
638:
639: /* Checks if there is any buffered output, and tries to write some of the
640: output. */
641:
1.2 provos 642: void
643: packet_write_poll()
1.1 deraadt 644: {
645: int len = buffer_len(&output);
646: if (len > 0)
647: {
648: len = write(connection_out, buffer_ptr(&output), len);
1.2 provos 649: if (len <= 0) {
1.1 deraadt 650: if (errno == EAGAIN)
651: return;
652: else
653: fatal("Write failed: %.100s", strerror(errno));
1.2 provos 654: }
1.1 deraadt 655: buffer_consume(&output, len);
656: }
657: }
658:
659: /* Calls packet_write_poll repeatedly until all pending output data has
660: been written. */
661:
1.2 provos 662: void
663: packet_write_wait()
1.1 deraadt 664: {
665: packet_write_poll();
666: while (packet_have_data_to_write())
667: {
668: fd_set set;
669: FD_ZERO(&set);
670: FD_SET(connection_out, &set);
671: select(connection_out + 1, NULL, &set, NULL, NULL);
672: packet_write_poll();
673: }
674: }
675:
676: /* Returns true if there is buffered data to write to the connection. */
677:
1.2 provos 678: int
679: packet_have_data_to_write()
1.1 deraadt 680: {
681: return buffer_len(&output) != 0;
682: }
683:
684: /* Returns true if there is not too much data to write to the connection. */
685:
1.2 provos 686: int
687: packet_not_very_much_data_to_write()
1.1 deraadt 688: {
689: if (interactive_mode)
690: return buffer_len(&output) < 16384;
691: else
692: return buffer_len(&output) < 128*1024;
693: }
694:
695: /* Informs that the current session is interactive. Sets IP flags for that. */
696:
1.2 provos 697: void
698: packet_set_interactive(int interactive, int keepalives)
1.1 deraadt 699: {
700: int on = 1;
701:
702: /* Record that we are in interactive mode. */
703: interactive_mode = interactive;
704:
705: /* Only set socket options if using a socket (as indicated by the descriptors
706: being the same). */
707: if (connection_in != connection_out)
708: return;
709:
710: if (keepalives)
711: {
712: /* Set keepalives if requested. */
713: if (setsockopt(connection_in, SOL_SOCKET, SO_KEEPALIVE, (void *)&on,
714: sizeof(on)) < 0)
715: error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
716: }
717:
718: if (interactive)
719: {
720: /* Set IP options for an interactive connection. Use IPTOS_LOWDELAY
721: and TCP_NODELAY. */
722: int lowdelay = IPTOS_LOWDELAY;
723: if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, (void *)&lowdelay,
724: sizeof(lowdelay)) < 0)
725: error("setsockopt IPTOS_LOWDELAY: %.100s", strerror(errno));
726: if (setsockopt(connection_in, IPPROTO_TCP, TCP_NODELAY, (void *)&on,
727: sizeof(on)) < 0)
728: error("setsockopt TCP_NODELAY: %.100s", strerror(errno));
729: }
730: else
731: {
732: /* Set IP options for a non-interactive connection. Use
733: IPTOS_THROUGHPUT. */
734: int throughput = IPTOS_THROUGHPUT;
735: if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, (void *)&throughput,
736: sizeof(throughput)) < 0)
737: error("setsockopt IPTOS_THROUGHPUT: %.100s", strerror(errno));
738: }
739: }
740:
741: /* Returns true if the current connection is interactive. */
742:
1.2 provos 743: int
744: packet_is_interactive()
1.1 deraadt 745: {
746: return interactive_mode;
747: }
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