aboutsummaryrefslogtreecommitdiff
path: root/libssh/socket.c
blob: a3df513ea06c293edcd4977ef62f57ac89f51c16 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
/* socket.c */
/* the Socket class */
/*
 * Copyright (c) 2008 Aris Adamantiadis
 *
 * This file is part of the SSH Library
 *
 * The SSH Library is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, or (at your
 * option) any later version.
 *
 * The SSH Library is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with the SSH Library; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 * MA 02111-1307, USA. */

#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>
#ifdef _WIN32
#include <winsock2.h>
#else
#include <fcntl.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#endif
#include "libssh/priv.h"

#if !defined(HAVE_SELECT) && !defined(HAVE_POLL)
#error Your system must have either select() or poll()
#endif

#if !defined(HAVE_POLL) && !defined(_WIN32)
#warning your system does not have poll. Select has known limitations
#define SELECT_LIMIT_CHECK
#endif

#ifdef HAVE_POLL
#define USE_POLL
#include <poll.h>
#else
#define USE_SELECT
#endif

/** \defgroup ssh_socket Sockets
 * \addtogroup ssh_socket
 * @{
 */

struct socket {
	socket_t fd;
	int last_errno;
    int data_to_read; /* reading now on socket will
                         not block */
    int data_to_write;
    int data_except;
    BUFFER *out_buffer;
    BUFFER *in_buffer;
    SSH_SESSION *session;
};

/*
 * \internal
 * \brief inits the socket system (windows specific)
 */
void ssh_socket_init(void){
#ifdef _WIN32
    struct WSAData wsaData;
    if (WSAStartup(MAKEWORD(2, 0), &wsaData)) {
        ssh_say(1,"Error initialising Windows sockets.\n");
    }
#endif
}
/*
 * \internal
 * \brief creates a new Socket object
 */
struct socket *ssh_socket_new(SSH_SESSION *session){
	struct socket *s=malloc(sizeof(struct socket));
	s->fd=-1;
	s->last_errno=-1;
	s->session=session;
	s->in_buffer=buffer_new();
	s->out_buffer=buffer_new();
	s->data_to_read=0;
	s->data_to_write=0;
	s->data_except=0;
	return s;
}

/* \internal
 * \brief Deletes a socket object
 */
void ssh_socket_free(struct socket *s){
    ssh_socket_close(s);
    buffer_free(s->in_buffer);
    buffer_free(s->out_buffer);
	free(s);
}

#ifndef _WIN32
int ssh_socket_unix(struct socket *s, const char *path) {
  struct sockaddr_un sunaddr;

  sunaddr.sun_family = AF_UNIX;
  snprintf(sunaddr.sun_path, sizeof(sunaddr.sun_path), "%s", path);

  s->fd = socket(AF_UNIX, SOCK_STREAM, 0);
  if (s->fd < 0) {
    return -1;
  }

  if (fcntl(s->fd, F_SETFD, 1) == -1) {
    close(s->fd);
    s->fd = -1;
    return -1;
  }

  if (connect(s->fd, (struct sockaddr *) &sunaddr,
        sizeof(sunaddr)) < 0) {
    close(s->fd);
    s->fd = -1;
    return -1;
  }

  return 0;
}
#endif

/* \internal
 * \brief closes a socket
 */
void ssh_socket_close(struct socket *s){
	if(ssh_socket_is_open(s)){
#ifdef _WIN32
		closesocket(s->fd);
		s->last_errno=WSAGetLastError();
#else
		close(s->fd);
		s->last_errno=errno;
#endif
		s->fd=-1;
	}
}

/* \internal
 * \brief sets the file descriptor of the socket
 */
void ssh_socket_set_fd(struct socket *s, socket_t fd){
	s->fd=fd;
}

/* \internal
 * \brief returns the file descriptor of the socket
 */
socket_t ssh_socket_get_fd(struct socket *s){
	return s->fd;
}

/* \internal
 * \brief returns nonzero if the socket is open
 */
int ssh_socket_is_open(struct socket *s){
	return s->fd != -1;
}

/* \internal
 * \brief read len bytes from socket into buffer
 */
static int ssh_socket_unbuffered_read(struct socket *s, void *buffer, u32 len) {
	int r;
	if(s->data_except)
		return -1;
	r=recv(s->fd,buffer,len,0);
#ifndef _WIN32
    s->last_errno=errno;
#else
    s->last_errno=WSAGetLastError();
#endif
    s->data_to_read=0;
    if(r<0)
    	s->data_except=1;
	return r;
}

/* \internal
 * \brief writes len bytes from buffer to socket
 */
static int ssh_socket_unbuffered_write(struct socket *s,const void *buffer,
    u32 len) {
	int w;
	if(s->data_except)
		return -1;
	w=send(s->fd,buffer,len,0);
#ifndef _WIN32
    s->last_errno=errno;
#else
    s->last_errno=WSAGetLastError();
#endif
    s->data_to_write=0;
    if(w<0)
    	s->data_except=1;
	return w;
}

/* \internal
 * \brief returns nonzero if the current socket is in the fd_set
 */
int ssh_socket_fd_isset(struct socket *s, fd_set *set){
	if(s->fd==-1)
		return 0;
	return FD_ISSET(s->fd,set);
}

/* \internal
 * \brief sets the current fd in a fd_set and updates the fd_max
 */

void ssh_socket_fd_set(struct socket *s, fd_set *set, int *fd_max){
	if(s->fd==-1)
		return;
	FD_SET(s->fd,set);
	if(s->fd>= *fd_max){
		*fd_max=s->fd+1;
	}
}

/** \internal
 * \brief reads blocking until len bytes have been read
 */
int ssh_socket_completeread(struct socket *s, void *buffer, u32 len){
    int r;
    u32 total=0;
    u32 toread=len;
    if(!ssh_socket_is_open(s))
        return SSH_ERROR;
    while((r=ssh_socket_unbuffered_read(s,buffer+total,toread))){
        if(r==-1)
            return SSH_ERROR;
        total += r;
        toread-=r;
        if(total==len)
            return len;
        if(r==0)
            return 0;
    }
    return total ; /* connection closed */
}

/** \internal
 * \brief Blocking write of len bytes
 */

int ssh_socket_completewrite(struct socket *s, void *buffer, u32 len){
    SSH_SESSION *session=s->session;
    int written;

    enter_function();
    if(!ssh_socket_is_open(s)){
        leave_function();
    	return SSH_ERROR;
    }
    while(len >0) {
        written=ssh_socket_unbuffered_write(s,buffer,len);
        if(written==0 || written==-1){
        	leave_function();
            return SSH_ERROR;
        }
        len-=written;
        buffer+=written;
    }
    leave_function();
    return SSH_OK;
}

/** \internal
 * \brief buffered read of data (complete)
 * \returns SSH_OK or SSH_ERROR.
 * \returns SSH_AGAIN in nonblocking mode
 */
int ssh_socket_read(struct socket *s, void *buffer, int len){
	SSH_SESSION *session=s->session;
	int ret;

	enter_function();
	ret = ssh_socket_wait_for_data(s, s->session, len);
	if(ret != SSH_OK){
		leave_function();
		return ret;
	}
	memcpy(buffer,buffer_get_rest(s->in_buffer),len);
	buffer_pass_bytes(s->in_buffer,len);
	leave_function();
	return SSH_OK;
}

#define WRITE_BUFFERING_THRESHOLD 65536
/** \internal
 * \brief buffered write of data
 * \returns SSH_OK, or SSH_ERROR
 * \warning has no effect on socket before a flush
 */
int ssh_socket_write(struct socket *s,const void *buffer, int len){
	SSH_SESSION *session=s->session;
	int ret;

	enter_function();
	buffer_add_data(s->out_buffer,buffer,len);
	if(buffer_get_rest_len(s->out_buffer) > WRITE_BUFFERING_THRESHOLD)
		ret=ssh_socket_nonblocking_flush(s);
	else
		ret=len;
	leave_function();
	return ret;
}


/** \internal
 * \brief wait for data on socket
 * \param s socket
 * \param session the ssh session
 * \param len number of bytes to be read
 * \returns SSH_OK bytes are available on socket
 * \returns SSH_AGAIN need to call later for data
 * \returns SSH_ERROR error happened
 */
int ssh_socket_wait_for_data(struct socket *s, SSH_SESSION *session, u32 len){
    int except, can_write;
    int to_read;
    int r;
    char *buf;
    char buffer[4096];
    enter_function();
    to_read=len - buffer_get_rest_len(s->in_buffer);
    if(to_read <= 0){
    	leave_function();
        return SSH_OK;
    }
    if(session->blocking){
        buf=malloc(to_read);
        r=ssh_socket_completeread(session->socket,buf,to_read);
        if(r==SSH_ERROR || r ==0){
            ssh_set_error(session,SSH_FATAL,
                (r==0)?"Connection closed by remote host" : "Error reading socket");
            ssh_socket_close(session->socket);
            session->alive=0;
            free(buf);
            leave_function();
            return SSH_ERROR;
        }

        buffer_add_data(s->in_buffer,buf,to_read);
        free(buf);
        leave_function();
        return SSH_OK;
    }
    /* nonblocking read */
    do {
        ssh_socket_poll(s,&can_write,&except); /* internally sets data_to_read */
        if(!s->data_to_read){
            leave_function();
        	return SSH_AGAIN;
        }

        /* read as much as we can */
        if(ssh_socket_is_open(session->socket))
            r=ssh_socket_unbuffered_read(session->socket,buffer,sizeof(buffer));
        else
            r=-1;
        if(r<=0){
            ssh_set_error(session,SSH_FATAL,
                (r==0)?"Connection closed by remote host" : "Error reading socket");
            ssh_socket_close(session->socket);
            session->alive=0;
            leave_function();
            return SSH_ERROR;
        }
        buffer_add_data(s->in_buffer,buffer, (u32) r);
    } while(buffer_get_rest_len(s->in_buffer)<len);
    leave_function();
    return SSH_OK;
}

#ifdef USE_SELECT
/* ssh_socket_poll, select() version */

/* \internal
 * \brief polls the socket for data
 * \param session ssh session
 * \param write value pointed to set to 1 if it is possible to write
 * \param except value pointed to set to 1 if there is an exception
 * \return 1 if it is possible to read, 0 otherwise, -1 on error
 */
int ssh_socket_poll(struct socket *s, int *write, int *except){
	SSH_SESSION *session=s->session;
    struct timeval sometime;
    fd_set rdes; // read set
    fd_set wdes; // writing set
    fd_set edes; // exception set
    int fdmax=-1;

    enter_function();
    FD_ZERO(&rdes);
    FD_ZERO(&wdes);
    FD_ZERO(&edes);

    if(!ssh_socket_is_open(s)){
        *except=1;
        *write=0;
        return 0;
    }
#ifdef SELECT_LIMIT_CHECK
    // some systems don't handle the fds > FD_SETSIZE
    if(s->fd > FD_SETSIZE){
    	ssh_set_error(session, SSH_REQUEST_DENIED, "File descriptor out of range for select : %d",s->fd);
    	leave_function();
    	return -1;
    }
#endif
    if(!s->data_to_read)
        ssh_socket_fd_set(s,&rdes,&fdmax);
    if(!s->data_to_write)
        ssh_socket_fd_set(s,&wdes,&fdmax);
    ssh_socket_fd_set(s,&edes,&fdmax);

    /* Set to return immediately (no blocking) */
    sometime.tv_sec = 0;
    sometime.tv_usec = 0;

    /* Make the call, and listen for errors */
    if (select(fdmax, &rdes,&wdes,&edes, &sometime) < 0) {
    	ssh_set_error(session,SSH_FATAL, "select: %s", strerror(errno));
    	leave_function();
    	return -1;
    }
    if(!s->data_to_read)
        s->data_to_read=ssh_socket_fd_isset(s,&rdes);
    if(!s->data_to_write)
        s->data_to_write=ssh_socket_fd_isset(s,&wdes);
    if(!s->data_except)
    	s->data_except=ssh_socket_fd_isset(s,&edes);
    *except=s->data_except;
    *write=s->data_to_write;
    leave_function();
    return s->data_to_read || (buffer_get_rest_len(s->in_buffer)>0);
}
#endif

#ifdef USE_POLL
/* ssh_socket_poll, poll() version */
int ssh_socket_poll(struct socket *s, int *write, int *except){
	SSH_SESSION *session=s->session;
	struct pollfd fd[1];
	int err;

	enter_function();
    if(!ssh_socket_is_open(s)){
        *except=1;
        *write=0;
        return 0;
    }
    fd->fd=s->fd;
    fd->events=0;
    if(!s->data_to_read)
        fd->events |= POLLIN;
    if(!s->data_to_write)
        fd->events |= POLLOUT;

    /* Make the call, and listen for errors */
    err=poll(fd,1,0);
    if(err<0){
    	ssh_set_error(session,SSH_FATAL, "select: %s", strerror(errno));
    	leave_function();
    	return -1;
    }
    if(!s->data_to_read)
        s->data_to_read=fd->revents & POLLIN;
    if(!s->data_to_write)
        s->data_to_write=fd->revents & POLLOUT;
    if(!s->data_except)
    	s->data_except=fd->revents & POLLERR;
    *except=s->data_except;
    *write=s->data_to_write;
    leave_function();
    return s->data_to_read || (buffer_get_rest_len(s->in_buffer)>0);
}
#endif

/** \internal
 * \brief nonblocking flush of the output buffer
 */
int ssh_socket_nonblocking_flush(struct socket *s){
    int except, can_write;
    int w;
    SSH_SESSION *session=s->session;
    enter_function();
    ssh_socket_poll(s,&can_write,&except); /* internally sets data_to_write */
    if(!ssh_socket_is_open(s)){
        session->alive=0;
        // FIXME use ssh_socket_get_errno
        ssh_set_error(session,SSH_FATAL,"Writing packet : error on socket (or connection closed): %s",strerror(errno));
        leave_function();
        return SSH_ERROR;
    }
    while(s->data_to_write && buffer_get_rest_len(s->out_buffer)>0){
        if(ssh_socket_is_open(s)){
            w=ssh_socket_unbuffered_write(s,buffer_get_rest(s->out_buffer),
                buffer_get_rest_len(s->out_buffer));
        } else
            w=-1; /* write failed */
        if(w<0){
            session->alive=0;
            ssh_socket_close(s);
            // FIXME use ssh_socket_get_errno()
            ssh_set_error(session,SSH_FATAL,"Writing packet : error on socket (or connection closed): %s",
                          strerror(errno));
            leave_function();
            return SSH_ERROR;
        }
        buffer_pass_bytes(s->out_buffer,w);
        /* refresh the socket status */
        ssh_socket_poll(session->socket,&can_write,&except);
    }
    if(buffer_get_rest_len(s->out_buffer)>0){
        leave_function();
    	return SSH_AGAIN;  /* there is data pending */
    }
    leave_function();
    return SSH_OK; // all data written
}


/** \internal
 * \brief locking flush of the output packet buffer
 */
int ssh_socket_blocking_flush(struct socket *s){
	SSH_SESSION *session=s->session;
	enter_function();
    if(!ssh_socket_is_open(s)) {
        session->alive=0;
        leave_function();
        return SSH_ERROR;
    }
    if(s->data_except){
        leave_function();
    	return SSH_ERROR;
    }
    if(buffer_get_rest_len(s->out_buffer)==0){
    	leave_function();
        return SSH_OK;
    }
    if(ssh_socket_completewrite(s,buffer_get_rest(s->out_buffer),
       buffer_get_rest_len(s->out_buffer))){
        session->alive=0;
        ssh_socket_close(s);
        // FIXME use the proper errno
        ssh_set_error(session,SSH_FATAL,"Writing packet : error on socket (or connection closed): %s",
                         strerror(errno));
        leave_function();
        return SSH_ERROR;
    }
    buffer_reinit(s->out_buffer);
    leave_function();
    return SSH_OK; // no data pending
}

void ssh_socket_set_towrite(struct socket *s){
	s->data_to_write=1;
}

void ssh_socket_set_toread(struct socket *s){
	s->data_to_read=1;
}

void ssh_socket_set_except(struct socket *s){
	s->data_except=1;
}

int ssh_socket_data_available(struct socket *s){
	return s->data_to_read;
}

int ssh_socket_data_writable(struct socket *s){
	return s->data_to_write;
}

int ssh_socket_get_status(struct socket *s){
	int r=0;
	if(s->data_to_read)
		r |= SSH_READ_PENDING;
	if(s->data_except)
		r|= SSH_CLOSED_ERROR;
	return r;
}

/** @}
 */