1 /*
2  *  TCP/IP or UDP/IP networking functions
3  *
4  *  Copyright The Mbed TLS Contributors
5  *  SPDX-License-Identifier: Apache-2.0
6  *
7  *  Licensed under the Apache License, Version 2.0 (the "License"); you may
8  *  not use this file except in compliance with the License.
9  *  You may obtain a copy of the License at
10  *
11  *  http://www.apache.org/licenses/LICENSE-2.0
12  *
13  *  Unless required by applicable law or agreed to in writing, software
14  *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
15  *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16  *  See the License for the specific language governing permissions and
17  *  limitations under the License.
18  */
19 
20 /* Enable definition of getaddrinfo() even when compiling with -std=c99. Must
21  * be set before mbedtls_config.h, which pulls in glibc's features.h indirectly.
22  * Harmless on other platforms. */
23 #ifndef _POSIX_C_SOURCE
24 #define _POSIX_C_SOURCE 200112L
25 #endif
26 #ifndef _XOPEN_SOURCE
27 #define _XOPEN_SOURCE 600 /* sockaddr_storage */
28 #endif
29 
30 #include "common.h"
31 
32 #if defined(MBEDTLS_NET_C)
33 
34 #if !defined(unix) && !defined(__unix__) && !defined(__unix) && \
35     !defined(__APPLE__) && !defined(_WIN32) && !defined(__QNXNTO__) && \
36     !defined(__HAIKU__) && !defined(__midipix__)
37 #error "This module only works on Unix and Windows, see MBEDTLS_NET_C in mbedtls_config.h"
38 #endif
39 
40 #include "mbedtls/platform.h"
41 
42 #include "mbedtls/net_sockets.h"
43 #include "mbedtls/error.h"
44 
45 #include <string.h>
46 
47 #if (defined(_WIN32) || defined(_WIN32_WCE)) && !defined(EFIX64) && \
48     !defined(EFI32)
49 
50 #define IS_EINTR(ret) ((ret) == WSAEINTR)
51 
52 #if !defined(_WIN32_WINNT)
53 /* Enables getaddrinfo() & Co */
54 #define _WIN32_WINNT 0x0501
55 #endif
56 
57 #include <ws2tcpip.h>
58 
59 #include <winsock2.h>
60 #include <windows.h>
61 #if (_WIN32_WINNT < 0x0501)
62 #include <wspiapi.h>
63 #endif
64 
65 #if defined(_MSC_VER)
66 #if defined(_WIN32_WCE)
67 #pragma comment( lib, "ws2.lib" )
68 #else
69 #pragma comment( lib, "ws2_32.lib" )
70 #endif
71 #endif /* _MSC_VER */
72 
73 #define read(fd, buf, len)        recv(fd, (char *) (buf), (int) (len), 0)
74 #define write(fd, buf, len)       send(fd, (char *) (buf), (int) (len), 0)
75 #define close(fd)               closesocket(fd)
76 
77 static int wsa_init_done = 0;
78 
79 #else /* ( _WIN32 || _WIN32_WCE ) && !EFIX64 && !EFI32 */
80 
81 #include <sys/types.h>
82 #include <sys/socket.h>
83 #include <netinet/in.h>
84 #include <arpa/inet.h>
85 #include <sys/time.h>
86 #include <unistd.h>
87 #include <signal.h>
88 #include <fcntl.h>
89 #include <netdb.h>
90 #include <errno.h>
91 
92 #define IS_EINTR(ret) ((ret) == EINTR)
93 
94 #endif /* ( _WIN32 || _WIN32_WCE ) && !EFIX64 && !EFI32 */
95 
96 /* Some MS functions want int and MSVC warns if we pass size_t,
97  * but the standard functions use socklen_t, so cast only for MSVC */
98 #if defined(_MSC_VER)
99 #define MSVC_INT_CAST   (int)
100 #else
101 #define MSVC_INT_CAST
102 #endif
103 
104 #include <stdio.h>
105 
106 #if defined(MBEDTLS_HAVE_TIME)
107 #include <time.h>
108 #endif
109 
110 #include <stdint.h>
111 
112 /*
113  * Prepare for using the sockets interface
114  */
net_prepare(void)115 static int net_prepare(void)
116 {
117 #if (defined(_WIN32) || defined(_WIN32_WCE)) && !defined(EFIX64) && \
118     !defined(EFI32)
119     WSADATA wsaData;
120 
121     if (wsa_init_done == 0) {
122         if (WSAStartup(MAKEWORD(2, 0), &wsaData) != 0) {
123             return MBEDTLS_ERR_NET_SOCKET_FAILED;
124         }
125 
126         wsa_init_done = 1;
127     }
128 #else
129 #if !defined(EFIX64) && !defined(EFI32)
130     signal(SIGPIPE, SIG_IGN);
131 #endif
132 #endif
133     return 0;
134 }
135 
136 /*
137  * Return 0 if the file descriptor is valid, an error otherwise.
138  * If for_select != 0, check whether the file descriptor is within the range
139  * allowed for fd_set used for the FD_xxx macros and the select() function.
140  */
check_fd(int fd,int for_select)141 static int check_fd(int fd, int for_select)
142 {
143     if (fd < 0) {
144         return MBEDTLS_ERR_NET_INVALID_CONTEXT;
145     }
146 
147 #if (defined(_WIN32) || defined(_WIN32_WCE)) && !defined(EFIX64) && \
148     !defined(EFI32)
149     (void) for_select;
150 #else
151     /* A limitation of select() is that it only works with file descriptors
152      * that are strictly less than FD_SETSIZE. This is a limitation of the
153      * fd_set type. Error out early, because attempting to call FD_SET on a
154      * large file descriptor is a buffer overflow on typical platforms. */
155     if (for_select && fd >= FD_SETSIZE) {
156         return MBEDTLS_ERR_NET_POLL_FAILED;
157     }
158 #endif
159 
160     return 0;
161 }
162 
163 /*
164  * Initialize a context
165  */
mbedtls_net_init(mbedtls_net_context * ctx)166 void mbedtls_net_init(mbedtls_net_context *ctx)
167 {
168     ctx->fd = -1;
169 }
170 
171 /*
172  * Initiate a TCP connection with host:port and the given protocol
173  */
mbedtls_net_connect(mbedtls_net_context * ctx,const char * host,const char * port,int proto)174 int mbedtls_net_connect(mbedtls_net_context *ctx, const char *host,
175                         const char *port, int proto)
176 {
177     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
178     struct addrinfo hints, *addr_list, *cur;
179 
180     if ((ret = net_prepare()) != 0) {
181         return ret;
182     }
183 
184     /* Do name resolution with both IPv6 and IPv4 */
185     memset(&hints, 0, sizeof(hints));
186     hints.ai_family = AF_UNSPEC;
187     hints.ai_socktype = proto == MBEDTLS_NET_PROTO_UDP ? SOCK_DGRAM : SOCK_STREAM;
188     hints.ai_protocol = proto == MBEDTLS_NET_PROTO_UDP ? IPPROTO_UDP : IPPROTO_TCP;
189 
190     if (getaddrinfo(host, port, &hints, &addr_list) != 0) {
191         return MBEDTLS_ERR_NET_UNKNOWN_HOST;
192     }
193 
194     /* Try the sockaddrs until a connection succeeds */
195     ret = MBEDTLS_ERR_NET_UNKNOWN_HOST;
196     for (cur = addr_list; cur != NULL; cur = cur->ai_next) {
197         ctx->fd = (int) socket(cur->ai_family, cur->ai_socktype,
198                                cur->ai_protocol);
199         if (ctx->fd < 0) {
200             ret = MBEDTLS_ERR_NET_SOCKET_FAILED;
201             continue;
202         }
203 
204         if (connect(ctx->fd, cur->ai_addr, MSVC_INT_CAST cur->ai_addrlen) == 0) {
205             ret = 0;
206             break;
207         }
208 
209         close(ctx->fd);
210         ret = MBEDTLS_ERR_NET_CONNECT_FAILED;
211     }
212 
213     freeaddrinfo(addr_list);
214 
215     return ret;
216 }
217 
218 /*
219  * Create a listening socket on bind_ip:port
220  */
mbedtls_net_bind(mbedtls_net_context * ctx,const char * bind_ip,const char * port,int proto)221 int mbedtls_net_bind(mbedtls_net_context *ctx, const char *bind_ip, const char *port, int proto)
222 {
223     int n, ret;
224     struct addrinfo hints, *addr_list, *cur;
225 
226     if ((ret = net_prepare()) != 0) {
227         return ret;
228     }
229 
230     /* Bind to IPv6 and/or IPv4, but only in the desired protocol */
231     memset(&hints, 0, sizeof(hints));
232     hints.ai_family = AF_UNSPEC;
233     hints.ai_socktype = proto == MBEDTLS_NET_PROTO_UDP ? SOCK_DGRAM : SOCK_STREAM;
234     hints.ai_protocol = proto == MBEDTLS_NET_PROTO_UDP ? IPPROTO_UDP : IPPROTO_TCP;
235     if (bind_ip == NULL) {
236         hints.ai_flags = AI_PASSIVE;
237     }
238 
239     if (getaddrinfo(bind_ip, port, &hints, &addr_list) != 0) {
240         return MBEDTLS_ERR_NET_UNKNOWN_HOST;
241     }
242 
243     /* Try the sockaddrs until a binding succeeds */
244     ret = MBEDTLS_ERR_NET_UNKNOWN_HOST;
245     for (cur = addr_list; cur != NULL; cur = cur->ai_next) {
246         ctx->fd = (int) socket(cur->ai_family, cur->ai_socktype,
247                                cur->ai_protocol);
248         if (ctx->fd < 0) {
249             ret = MBEDTLS_ERR_NET_SOCKET_FAILED;
250             continue;
251         }
252 
253         n = 1;
254         if (setsockopt(ctx->fd, SOL_SOCKET, SO_REUSEADDR,
255                        (const char *) &n, sizeof(n)) != 0) {
256             close(ctx->fd);
257             ret = MBEDTLS_ERR_NET_SOCKET_FAILED;
258             continue;
259         }
260 
261         if (bind(ctx->fd, cur->ai_addr, MSVC_INT_CAST cur->ai_addrlen) != 0) {
262             close(ctx->fd);
263             ret = MBEDTLS_ERR_NET_BIND_FAILED;
264             continue;
265         }
266 
267         /* Listen only makes sense for TCP */
268         if (proto == MBEDTLS_NET_PROTO_TCP) {
269             if (listen(ctx->fd, MBEDTLS_NET_LISTEN_BACKLOG) != 0) {
270                 close(ctx->fd);
271                 ret = MBEDTLS_ERR_NET_LISTEN_FAILED;
272                 continue;
273             }
274         }
275 
276         /* Bind was successful */
277         ret = 0;
278         break;
279     }
280 
281     freeaddrinfo(addr_list);
282 
283     return ret;
284 
285 }
286 
287 #if (defined(_WIN32) || defined(_WIN32_WCE)) && !defined(EFIX64) && \
288     !defined(EFI32)
289 /*
290  * Check if the requested operation would be blocking on a non-blocking socket
291  * and thus 'failed' with a negative return value.
292  */
net_would_block(const mbedtls_net_context * ctx)293 static int net_would_block(const mbedtls_net_context *ctx)
294 {
295     ((void) ctx);
296     return WSAGetLastError() == WSAEWOULDBLOCK;
297 }
298 #else
299 /*
300  * Check if the requested operation would be blocking on a non-blocking socket
301  * and thus 'failed' with a negative return value.
302  *
303  * Note: on a blocking socket this function always returns 0!
304  */
net_would_block(const mbedtls_net_context * ctx)305 static int net_would_block(const mbedtls_net_context *ctx)
306 {
307     int err = errno;
308 
309     /*
310      * Never return 'WOULD BLOCK' on a blocking socket
311      */
312     if ((fcntl(ctx->fd, F_GETFL) & O_NONBLOCK) != O_NONBLOCK) {
313         errno = err;
314         return 0;
315     }
316 
317     switch (errno = err) {
318 #if defined EAGAIN
319         case EAGAIN:
320 #endif
321 #if defined EWOULDBLOCK && EWOULDBLOCK != EAGAIN
322         case EWOULDBLOCK:
323 #endif
324     return 1;
325     }
326     return 0;
327 }
328 #endif /* ( _WIN32 || _WIN32_WCE ) && !EFIX64 && !EFI32 */
329 
330 /*
331  * Accept a connection from a remote client
332  */
mbedtls_net_accept(mbedtls_net_context * bind_ctx,mbedtls_net_context * client_ctx,void * client_ip,size_t buf_size,size_t * ip_len)333 int mbedtls_net_accept(mbedtls_net_context *bind_ctx,
334                        mbedtls_net_context *client_ctx,
335                        void *client_ip, size_t buf_size, size_t *ip_len)
336 {
337     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
338     int type;
339 
340     struct sockaddr_storage client_addr;
341 
342 #if defined(__socklen_t_defined) || defined(_SOCKLEN_T) ||  \
343     defined(_SOCKLEN_T_DECLARED) || defined(__DEFINED_socklen_t) || \
344     defined(socklen_t) || (defined(_POSIX_VERSION) && _POSIX_VERSION >= 200112L)
345     socklen_t n = (socklen_t) sizeof(client_addr);
346     socklen_t type_len = (socklen_t) sizeof(type);
347 #else
348     int n = (int) sizeof(client_addr);
349     int type_len = (int) sizeof(type);
350 #endif
351 
352     /* Is this a TCP or UDP socket? */
353     if (getsockopt(bind_ctx->fd, SOL_SOCKET, SO_TYPE,
354                    (void *) &type, &type_len) != 0 ||
355         (type != SOCK_STREAM && type != SOCK_DGRAM)) {
356         return MBEDTLS_ERR_NET_ACCEPT_FAILED;
357     }
358 
359     if (type == SOCK_STREAM) {
360         /* TCP: actual accept() */
361         ret = client_ctx->fd = (int) accept(bind_ctx->fd,
362                                             (struct sockaddr *) &client_addr, &n);
363     } else {
364         /* UDP: wait for a message, but keep it in the queue */
365         char buf[1] = { 0 };
366 
367         ret = (int) recvfrom(bind_ctx->fd, buf, sizeof(buf), MSG_PEEK,
368                              (struct sockaddr *) &client_addr, &n);
369 
370 #if defined(_WIN32)
371         if (ret == SOCKET_ERROR &&
372             WSAGetLastError() == WSAEMSGSIZE) {
373             /* We know buf is too small, thanks, just peeking here */
374             ret = 0;
375         }
376 #endif
377     }
378 
379     if (ret < 0) {
380         if (net_would_block(bind_ctx) != 0) {
381             return MBEDTLS_ERR_SSL_WANT_READ;
382         }
383 
384         return MBEDTLS_ERR_NET_ACCEPT_FAILED;
385     }
386 
387     /* UDP: hijack the listening socket to communicate with the client,
388      * then bind a new socket to accept new connections */
389     if (type != SOCK_STREAM) {
390         struct sockaddr_storage local_addr;
391         int one = 1;
392 
393         if (connect(bind_ctx->fd, (struct sockaddr *) &client_addr, n) != 0) {
394             return MBEDTLS_ERR_NET_ACCEPT_FAILED;
395         }
396 
397         client_ctx->fd = bind_ctx->fd;
398         bind_ctx->fd   = -1; /* In case we exit early */
399 
400         n = sizeof(struct sockaddr_storage);
401         if (getsockname(client_ctx->fd,
402                         (struct sockaddr *) &local_addr, &n) != 0 ||
403             (bind_ctx->fd = (int) socket(local_addr.ss_family,
404                                          SOCK_DGRAM, IPPROTO_UDP)) < 0 ||
405             setsockopt(bind_ctx->fd, SOL_SOCKET, SO_REUSEADDR,
406                        (const char *) &one, sizeof(one)) != 0) {
407             return MBEDTLS_ERR_NET_SOCKET_FAILED;
408         }
409 
410         if (bind(bind_ctx->fd, (struct sockaddr *) &local_addr, n) != 0) {
411             return MBEDTLS_ERR_NET_BIND_FAILED;
412         }
413     }
414 
415     if (client_ip != NULL) {
416         if (client_addr.ss_family == AF_INET) {
417             struct sockaddr_in *addr4 = (struct sockaddr_in *) &client_addr;
418             *ip_len = sizeof(addr4->sin_addr.s_addr);
419 
420             if (buf_size < *ip_len) {
421                 return MBEDTLS_ERR_NET_BUFFER_TOO_SMALL;
422             }
423 
424             memcpy(client_ip, &addr4->sin_addr.s_addr, *ip_len);
425         } else {
426             struct sockaddr_in6 *addr6 = (struct sockaddr_in6 *) &client_addr;
427             *ip_len = sizeof(addr6->sin6_addr.s6_addr);
428 
429             if (buf_size < *ip_len) {
430                 return MBEDTLS_ERR_NET_BUFFER_TOO_SMALL;
431             }
432 
433             memcpy(client_ip, &addr6->sin6_addr.s6_addr, *ip_len);
434         }
435     }
436 
437     return 0;
438 }
439 
440 /*
441  * Set the socket blocking or non-blocking
442  */
mbedtls_net_set_block(mbedtls_net_context * ctx)443 int mbedtls_net_set_block(mbedtls_net_context *ctx)
444 {
445 #if (defined(_WIN32) || defined(_WIN32_WCE)) && !defined(EFIX64) && \
446     !defined(EFI32)
447     u_long n = 0;
448     return ioctlsocket(ctx->fd, FIONBIO, &n);
449 #else
450     return fcntl(ctx->fd, F_SETFL, fcntl(ctx->fd, F_GETFL) & ~O_NONBLOCK);
451 #endif
452 }
453 
mbedtls_net_set_nonblock(mbedtls_net_context * ctx)454 int mbedtls_net_set_nonblock(mbedtls_net_context *ctx)
455 {
456 #if (defined(_WIN32) || defined(_WIN32_WCE)) && !defined(EFIX64) && \
457     !defined(EFI32)
458     u_long n = 1;
459     return ioctlsocket(ctx->fd, FIONBIO, &n);
460 #else
461     return fcntl(ctx->fd, F_SETFL, fcntl(ctx->fd, F_GETFL) | O_NONBLOCK);
462 #endif
463 }
464 
465 /*
466  * Check if data is available on the socket
467  */
468 
mbedtls_net_poll(mbedtls_net_context * ctx,uint32_t rw,uint32_t timeout)469 int mbedtls_net_poll(mbedtls_net_context *ctx, uint32_t rw, uint32_t timeout)
470 {
471     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
472     struct timeval tv;
473 
474     fd_set read_fds;
475     fd_set write_fds;
476 
477     int fd = ctx->fd;
478 
479     ret = check_fd(fd, 1);
480     if (ret != 0) {
481         return ret;
482     }
483 
484 #if defined(__has_feature)
485 #if __has_feature(memory_sanitizer)
486     /* Ensure that memory sanitizers consider read_fds and write_fds as
487      * initialized even on platforms such as Glibc/x86_64 where FD_ZERO
488      * is implemented in assembly. */
489     memset(&read_fds, 0, sizeof(read_fds));
490     memset(&write_fds, 0, sizeof(write_fds));
491 #endif
492 #endif
493 
494     FD_ZERO(&read_fds);
495     if (rw & MBEDTLS_NET_POLL_READ) {
496         rw &= ~MBEDTLS_NET_POLL_READ;
497         FD_SET(fd, &read_fds);
498     }
499 
500     FD_ZERO(&write_fds);
501     if (rw & MBEDTLS_NET_POLL_WRITE) {
502         rw &= ~MBEDTLS_NET_POLL_WRITE;
503         FD_SET(fd, &write_fds);
504     }
505 
506     if (rw != 0) {
507         return MBEDTLS_ERR_NET_BAD_INPUT_DATA;
508     }
509 
510     tv.tv_sec  = timeout / 1000;
511     tv.tv_usec = (timeout % 1000) * 1000;
512 
513     do {
514         ret = select(fd + 1, &read_fds, &write_fds, NULL,
515                      timeout == (uint32_t) -1 ? NULL : &tv);
516     } while (IS_EINTR(ret));
517 
518     if (ret < 0) {
519         return MBEDTLS_ERR_NET_POLL_FAILED;
520     }
521 
522     ret = 0;
523     if (FD_ISSET(fd, &read_fds)) {
524         ret |= MBEDTLS_NET_POLL_READ;
525     }
526     if (FD_ISSET(fd, &write_fds)) {
527         ret |= MBEDTLS_NET_POLL_WRITE;
528     }
529 
530     return ret;
531 }
532 
533 /*
534  * Portable usleep helper
535  */
mbedtls_net_usleep(unsigned long usec)536 void mbedtls_net_usleep(unsigned long usec)
537 {
538 #if defined(_WIN32)
539     Sleep((usec + 999) / 1000);
540 #else
541     struct timeval tv;
542     tv.tv_sec  = usec / 1000000;
543 #if defined(__unix__) || defined(__unix) || \
544     (defined(__APPLE__) && defined(__MACH__))
545     tv.tv_usec = (suseconds_t) usec % 1000000;
546 #else
547     tv.tv_usec = usec % 1000000;
548 #endif
549     select(0, NULL, NULL, NULL, &tv);
550 #endif
551 }
552 
553 /*
554  * Read at most 'len' characters
555  */
mbedtls_net_recv(void * ctx,unsigned char * buf,size_t len)556 int mbedtls_net_recv(void *ctx, unsigned char *buf, size_t len)
557 {
558     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
559     int fd = ((mbedtls_net_context *) ctx)->fd;
560 
561     ret = check_fd(fd, 0);
562     if (ret != 0) {
563         return ret;
564     }
565 
566     ret = (int) read(fd, buf, len);
567 
568     if (ret < 0) {
569         if (net_would_block(ctx) != 0) {
570             return MBEDTLS_ERR_SSL_WANT_READ;
571         }
572 
573 #if (defined(_WIN32) || defined(_WIN32_WCE)) && !defined(EFIX64) && \
574         !defined(EFI32)
575         if (WSAGetLastError() == WSAECONNRESET) {
576             return MBEDTLS_ERR_NET_CONN_RESET;
577         }
578 #else
579         if (errno == EPIPE || errno == ECONNRESET) {
580             return MBEDTLS_ERR_NET_CONN_RESET;
581         }
582 
583         if (errno == EINTR) {
584             return MBEDTLS_ERR_SSL_WANT_READ;
585         }
586 #endif
587 
588         return MBEDTLS_ERR_NET_RECV_FAILED;
589     }
590 
591     return ret;
592 }
593 
594 /*
595  * Read at most 'len' characters, blocking for at most 'timeout' ms
596  */
mbedtls_net_recv_timeout(void * ctx,unsigned char * buf,size_t len,uint32_t timeout)597 int mbedtls_net_recv_timeout(void *ctx, unsigned char *buf,
598                              size_t len, uint32_t timeout)
599 {
600     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
601     struct timeval tv;
602     fd_set read_fds;
603     int fd = ((mbedtls_net_context *) ctx)->fd;
604 
605     ret = check_fd(fd, 1);
606     if (ret != 0) {
607         return ret;
608     }
609 
610     FD_ZERO(&read_fds);
611     FD_SET(fd, &read_fds);
612 
613     tv.tv_sec  = timeout / 1000;
614     tv.tv_usec = (timeout % 1000) * 1000;
615 
616     ret = select(fd + 1, &read_fds, NULL, NULL, timeout == 0 ? NULL : &tv);
617 
618     /* Zero fds ready means we timed out */
619     if (ret == 0) {
620         return MBEDTLS_ERR_SSL_TIMEOUT;
621     }
622 
623     if (ret < 0) {
624 #if (defined(_WIN32) || defined(_WIN32_WCE)) && !defined(EFIX64) && \
625         !defined(EFI32)
626         if (WSAGetLastError() == WSAEINTR) {
627             return MBEDTLS_ERR_SSL_WANT_READ;
628         }
629 #else
630         if (errno == EINTR) {
631             return MBEDTLS_ERR_SSL_WANT_READ;
632         }
633 #endif
634 
635         return MBEDTLS_ERR_NET_RECV_FAILED;
636     }
637 
638     /* This call will not block */
639     return mbedtls_net_recv(ctx, buf, len);
640 }
641 
642 /*
643  * Write at most 'len' characters
644  */
mbedtls_net_send(void * ctx,const unsigned char * buf,size_t len)645 int mbedtls_net_send(void *ctx, const unsigned char *buf, size_t len)
646 {
647     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
648     int fd = ((mbedtls_net_context *) ctx)->fd;
649 
650     ret = check_fd(fd, 0);
651     if (ret != 0) {
652         return ret;
653     }
654 
655     ret = (int) write(fd, buf, len);
656 
657     if (ret < 0) {
658         if (net_would_block(ctx) != 0) {
659             return MBEDTLS_ERR_SSL_WANT_WRITE;
660         }
661 
662 #if (defined(_WIN32) || defined(_WIN32_WCE)) && !defined(EFIX64) && \
663         !defined(EFI32)
664         if (WSAGetLastError() == WSAECONNRESET) {
665             return MBEDTLS_ERR_NET_CONN_RESET;
666         }
667 #else
668         if (errno == EPIPE || errno == ECONNRESET) {
669             return MBEDTLS_ERR_NET_CONN_RESET;
670         }
671 
672         if (errno == EINTR) {
673             return MBEDTLS_ERR_SSL_WANT_WRITE;
674         }
675 #endif
676 
677         return MBEDTLS_ERR_NET_SEND_FAILED;
678     }
679 
680     return ret;
681 }
682 
683 /*
684  * Close the connection
685  */
mbedtls_net_close(mbedtls_net_context * ctx)686 void mbedtls_net_close(mbedtls_net_context *ctx)
687 {
688     if (ctx->fd == -1) {
689         return;
690     }
691 
692     close(ctx->fd);
693 
694     ctx->fd = -1;
695 }
696 
697 /*
698  * Gracefully close the connection
699  */
mbedtls_net_free(mbedtls_net_context * ctx)700 void mbedtls_net_free(mbedtls_net_context *ctx)
701 {
702     if (ctx->fd == -1) {
703         return;
704     }
705 
706     shutdown(ctx->fd, 2);
707     close(ctx->fd);
708 
709     ctx->fd = -1;
710 }
711 
712 #endif /* MBEDTLS_NET_C */
713