tool/mbed/mbed-sdk/libraries/net/lwip/lwip/api/api_lib.c

   1 /**
   2  * @file
   3  * Sequential API External module
   4  *
   5  */
   6
   7 /*
   8  * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
   9  * All rights reserved.
  10  *
  11  * Redistribution and use in source and binary forms, with or without modification,
  12  * are permitted provided that the following conditions are met:
  13  *
  14  * 1. Redistributions of source code must retain the above copyright notice,
  15  *    this list of conditions and the following disclaimer.
  16  * 2. Redistributions in binary form must reproduce the above copyright notice,
  17  *    this list of conditions and the following disclaimer in the documentation
  18  *    and/or other materials provided with the distribution.
  19  * 3. The name of the author may not be used to endorse or promote products
  20  *    derived from this software without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
  23  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  24  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
  25  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  26  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
  27  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  28  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  29  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  30  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
  31  * OF SUCH DAMAGE.
  32  *
  33  * This file is part of the lwIP TCP/IP stack.
  34  *
  35  * Author: Adam Dunkels <adam@sics.se>
  36  *
  37  */
  38
  39 /* This is the part of the API that is linked with
  40    the application */
  41
  42 #include "lwip/opt.h"
  43
  44 #if LWIP_NETCONN /* don't build if not configured for use in lwipopts.h */
  45
  46 #include "lwip/api.h"
  47 #include "lwip/tcpip.h"
  48 #include "lwip/memp.h"
  49
  50 #include "lwip/ip.h"
  51 #include "lwip/raw.h"
  52 #include "lwip/udp.h"
  53 #include "lwip/tcp.h"
  54
  55 #include <string.h>
  56
  57 /**
  58  * Create a new netconn (of a specific type) that has a callback function.
  59  * The corresponding pcb is also created.
  60  *
  61  * @param t the type of 'connection' to create (@see enum netconn_type)
  62  * @param proto the IP protocol for RAW IP pcbs
  63  * @param callback a function to call on status changes (RX available, TX'ed)
  64  * @return a newly allocated struct netconn or
  65  *         NULL on memory error
  66  */
  67 struct netconn*
  68 netconn_new_with_proto_and_callback(enum netconn_type t, u8_t proto, netconn_callback callback)
  69 {
  70   struct netconn *conn;
  71   struct api_msg msg;
  72
  73   conn = netconn_alloc(t, callback);
  74   if (conn != NULL) {
  75     msg.function = do_newconn;
  76     msg.msg.msg.n.proto = proto;
  77     msg.msg.conn = conn;
  78     if (TCPIP_APIMSG(&msg) != ERR_OK) {
  79       LWIP_ASSERT("freeing conn without freeing pcb", conn->pcb.tcp == NULL);
  80       LWIP_ASSERT("conn has no op_completed", sys_sem_valid(&conn->op_completed));
  81       LWIP_ASSERT("conn has no recvmbox", sys_mbox_valid(&conn->recvmbox));
  82 #if LWIP_TCP
  83       LWIP_ASSERT("conn->acceptmbox shouldn't exist", !sys_mbox_valid(&conn->acceptmbox));
  84 #endif /* LWIP_TCP */
  85       sys_sem_free(&conn->op_completed);
  86       sys_mbox_free(&conn->recvmbox);
  87       memp_free(MEMP_NETCONN, conn);
  88       return NULL;
  89     }
  90   }
  91   return conn;
  92 }
  93
  94 /**
  95  * Close a netconn 'connection' and free its resources.
  96  * UDP and RAW connection are completely closed, TCP pcbs might still be in a waitstate
  97  * after this returns.
  98  *
  99  * @param conn the netconn to delete
 100  * @return ERR_OK if the connection was deleted
 101  */
 102 err_t
 103 netconn_delete(struct netconn *conn)
 104 {
 105   struct api_msg msg;
 106
 107   /* No ASSERT here because possible to get a (conn == NULL) if we got an accept error */
 108   if (conn == NULL) {
 109     return ERR_OK;
 110   }
 111
 112   msg.function = do_delconn;
 113   msg.msg.conn = conn;
 114   tcpip_apimsg(&msg);
 115
 116   netconn_free(conn);
 117
 118   /* don't care for return value of do_delconn since it only calls void functions */
 119
 120   return ERR_OK;
 121 }
 122
 123 /**
 124  * Get the local or remote IP address and port of a netconn.
 125  * For RAW netconns, this returns the protocol instead of a port!
 126  *
 127  * @param conn the netconn to query
 128  * @param addr a pointer to which to save the IP address
 129  * @param port a pointer to which to save the port (or protocol for RAW)
 130  * @param local 1 to get the local IP address, 0 to get the remote one
 131  * @return ERR_CONN for invalid connections
 132  *         ERR_OK if the information was retrieved
 133  */
 134 err_t
 135 netconn_getaddr(struct netconn *conn, ip_addr_t *addr, u16_t *port, u8_t local)
 136 {
 137   struct api_msg msg;
 138   err_t err;
 139
 140   LWIP_ERROR("netconn_getaddr: invalid conn", (conn != NULL), return ERR_ARG;);
 141   LWIP_ERROR("netconn_getaddr: invalid addr", (addr != NULL), return ERR_ARG;);
 142   LWIP_ERROR("netconn_getaddr: invalid port", (port != NULL), return ERR_ARG;);
 143
 144   msg.function = do_getaddr;
 145   msg.msg.conn = conn;
 146   msg.msg.msg.ad.ipaddr = addr;
 147   msg.msg.msg.ad.port = port;
 148   msg.msg.msg.ad.local = local;
 149   err = TCPIP_APIMSG(&msg);
 150
 151   NETCONN_SET_SAFE_ERR(conn, err);
 152   return err;
 153 }
 154
 155 /**
 156  * Bind a netconn to a specific local IP address and port.
 157  * Binding one netconn twice might not always be checked correctly!
 158  *
 159  * @param conn the netconn to bind
 160  * @param addr the local IP address to bind the netconn to (use IP_ADDR_ANY
 161  *             to bind to all addresses)
 162  * @param port the local port to bind the netconn to (not used for RAW)
 163  * @return ERR_OK if bound, any other err_t on failure
 164  */
 165 err_t
 166 netconn_bind(struct netconn *conn, ip_addr_t *addr, u16_t port)
 167 {
 168   struct api_msg msg;
 169   err_t err;
 170
 171   LWIP_ERROR("netconn_bind: invalid conn", (conn != NULL), return ERR_ARG;);
 172
 173   msg.function = do_bind;
 174   msg.msg.conn = conn;
 175   msg.msg.msg.bc.ipaddr = addr;
 176   msg.msg.msg.bc.port = port;
 177   err = TCPIP_APIMSG(&msg);
 178
 179   NETCONN_SET_SAFE_ERR(conn, err);
 180   return err;
 181 }
 182
 183 /**
 184  * Connect a netconn to a specific remote IP address and port.
 185  *
 186  * @param conn the netconn to connect
 187  * @param addr the remote IP address to connect to
 188  * @param port the remote port to connect to (no used for RAW)
 189  * @return ERR_OK if connected, return value of tcp_/udp_/raw_connect otherwise
 190  */
 191 err_t
 192 netconn_connect(struct netconn *conn, ip_addr_t *addr, u16_t port)
 193 {
 194   struct api_msg msg;
 195   err_t err;
 196
 197   LWIP_ERROR("netconn_connect: invalid conn", (conn != NULL), return ERR_ARG;);
 198
 199   msg.function = do_connect;
 200   msg.msg.conn = conn;
 201   msg.msg.msg.bc.ipaddr = addr;
 202   msg.msg.msg.bc.port = port;
 203   /* This is the only function which need to not block tcpip_thread */
 204   err = tcpip_apimsg(&msg);
 205
 206   NETCONN_SET_SAFE_ERR(conn, err);
 207   return err;
 208 }
 209
 210 /**
 211  * Disconnect a netconn from its current peer (only valid for UDP netconns).
 212  *
 213  * @param conn the netconn to disconnect
 214  * @return TODO: return value is not set here...
 215  */
 216 err_t
 217 netconn_disconnect(struct netconn *conn)
 218 {
 219   struct api_msg msg;
 220   err_t err;
 221
 222   LWIP_ERROR("netconn_disconnect: invalid conn", (conn != NULL), return ERR_ARG;);
 223
 224   msg.function = do_disconnect;
 225   msg.msg.conn = conn;
 226   err = TCPIP_APIMSG(&msg);
 227
 228   NETCONN_SET_SAFE_ERR(conn, err);
 229   return err;
 230 }
 231
 232 /**
 233  * Set a TCP netconn into listen mode
 234  *
 235  * @param conn the tcp netconn to set to listen mode
 236  * @param backlog the listen backlog, only used if TCP_LISTEN_BACKLOG==1
 237  * @return ERR_OK if the netconn was set to listen (UDP and RAW netconns
 238  *         don't return any error (yet?))
 239  */
 240 err_t
 241 netconn_listen_with_backlog(struct netconn *conn, u8_t backlog)
 242 {
 243 #if LWIP_TCP
 244   struct api_msg msg;
 245   err_t err;
 246
 247   /* This does no harm. If TCP_LISTEN_BACKLOG is off, backlog is unused. */
 248   LWIP_UNUSED_ARG(backlog);
 249
 250   LWIP_ERROR("netconn_listen: invalid conn", (conn != NULL), return ERR_ARG;);
 251
 252   msg.function = do_listen;
 253   msg.msg.conn = conn;
 254 #if TCP_LISTEN_BACKLOG
 255   msg.msg.msg.lb.backlog = backlog;
 256 #endif /* TCP_LISTEN_BACKLOG */
 257   err = TCPIP_APIMSG(&msg);
 258
 259   NETCONN_SET_SAFE_ERR(conn, err);
 260   return err;
 261 #else /* LWIP_TCP */
 262   LWIP_UNUSED_ARG(conn);
 263   LWIP_UNUSED_ARG(backlog);
 264   return ERR_ARG;
 265 #endif /* LWIP_TCP */
 266 }
 267
 268 /**
 269  * Accept a new connection on a TCP listening netconn.
 270  *
 271  * @param conn the TCP listen netconn
 272  * @param new_conn pointer where the new connection is stored
 273  * @return ERR_OK if a new connection has been received or an error
 274  *                code otherwise
 275  */
 276 err_t
 277 netconn_accept(struct netconn *conn, struct netconn **new_conn)
 278 {
 279 #if LWIP_TCP
 280   struct netconn *newconn;
 281   err_t err;
 282 #if TCP_LISTEN_BACKLOG
 283   struct api_msg msg;
 284 #endif /* TCP_LISTEN_BACKLOG */
 285
 286   LWIP_ERROR("netconn_accept: invalid pointer",    (new_conn != NULL),                  return ERR_ARG;);
 287   *new_conn = NULL;
 288   LWIP_ERROR("netconn_accept: invalid conn",       (conn != NULL),                      return ERR_ARG;);
 289   LWIP_ERROR("netconn_accept: invalid acceptmbox", sys_mbox_valid(&conn->acceptmbox),   return ERR_ARG;);
 290
 291   err = conn->last_err;
 292   if (ERR_IS_FATAL(err)) {
 293     /* don't recv on fatal errors: this might block the application task
 294        waiting on acceptmbox forever! */
 295     return err;
 296   }
 297
 298 #if LWIP_SO_RCVTIMEO
 299   if (sys_arch_mbox_fetch(&conn->acceptmbox, (void **)&newconn, conn->recv_timeout) == SYS_ARCH_TIMEOUT) {
 300     NETCONN_SET_SAFE_ERR(conn, ERR_TIMEOUT);
 301     return ERR_TIMEOUT;
 302   }
 303 #else
 304   sys_arch_mbox_fetch(&conn->acceptmbox, (void **)&newconn, 0);
 305 #endif /* LWIP_SO_RCVTIMEO*/
 306   /* Register event with callback */
 307   API_EVENT(conn, NETCONN_EVT_RCVMINUS, 0);
 308
 309   if (newconn == NULL) {
 310     /* connection has been aborted */
 311     NETCONN_SET_SAFE_ERR(conn, ERR_ABRT);
 312     return ERR_ABRT;
 313   }
 314 #if TCP_LISTEN_BACKLOG
 315   /* Let the stack know that we have accepted the connection. */
 316   msg.function = do_recv;
 317   msg.msg.conn = conn;
 318   /* don't care for the return value of do_recv */
 319   TCPIP_APIMSG(&msg);
 320 #endif /* TCP_LISTEN_BACKLOG */
 321
 322   *new_conn = newconn;
 323   /* don't set conn->last_err: it's only ERR_OK, anyway */
 324   return ERR_OK;
 325 #else /* LWIP_TCP */
 326   LWIP_UNUSED_ARG(conn);
 327   LWIP_UNUSED_ARG(new_conn);
 328   return ERR_ARG;
 329 #endif /* LWIP_TCP */
 330 }
 331
 332 /**
 333  * Receive data: actual implementation that doesn't care whether pbuf or netbuf
 334  * is received
 335  *
 336  * @param conn the netconn from which to receive data
 337  * @param new_buf pointer where a new pbuf/netbuf is stored when received data
 338  * @return ERR_OK if data has been received, an error code otherwise (timeout,
 339  *                memory error or another error)
 340  */
 341 static err_t
 342 netconn_recv_data(struct netconn *conn, void **new_buf)
 343 {
 344   void *buf = NULL;
 345   u16_t len;
 346   err_t err;
 347 #if LWIP_TCP
 348   struct api_msg msg;
 349 #endif /* LWIP_TCP */
 350
 351   LWIP_ERROR("netconn_recv: invalid pointer", (new_buf != NULL), return ERR_ARG;);
 352   *new_buf = NULL;
 353   LWIP_ERROR("netconn_recv: invalid conn",    (conn != NULL),    return ERR_ARG;);
 354   LWIP_ERROR("netconn_accept: invalid recvmbox", sys_mbox_valid(&conn->recvmbox), return ERR_CONN;);
 355
 356   err = conn->last_err;
 357   if (ERR_IS_FATAL(err)) {
 358     /* don't recv on fatal errors: this might block the application task
 359        waiting on recvmbox forever! */
 360     /* @todo: this does not allow us to fetch data that has been put into recvmbox
 361        before the fatal error occurred - is that a problem? */
 362     return err;
 363   }
 364
 365 #if LWIP_SO_RCVTIMEO
 366   if (sys_arch_mbox_fetch(&conn->recvmbox, &buf, conn->recv_timeout) == SYS_ARCH_TIMEOUT) {
 367     NETCONN_SET_SAFE_ERR(conn, ERR_TIMEOUT);
 368     return ERR_TIMEOUT;
 369   }
 370 #else
 371   sys_arch_mbox_fetch(&conn->recvmbox, &buf, 0);
 372 #endif /* LWIP_SO_RCVTIMEO*/
 373
 374 #if LWIP_TCP
 375   if (conn->type == NETCONN_TCP) {
 376     if (!netconn_get_noautorecved(conn) || (buf == NULL)) {
 377       /* Let the stack know that we have taken the data. */
 378       /* TODO: Speedup: Don't block and wait for the answer here
 379          (to prevent multiple thread-switches). */
 380       msg.function = do_recv;
 381       msg.msg.conn = conn;
 382       if (buf != NULL) {
 383         msg.msg.msg.r.len = ((struct pbuf *)buf)->tot_len;
 384       } else {
 385         msg.msg.msg.r.len = 1;
 386       }
 387       /* don't care for the return value of do_recv */
 388       TCPIP_APIMSG(&msg);
 389     }
 390
 391     /* If we are closed, we indicate that we no longer wish to use the socket */
 392     if (buf == NULL) {
 393       API_EVENT(conn, NETCONN_EVT_RCVMINUS, 0);
 394       /* Avoid to lose any previous error code */
 395       NETCONN_SET_SAFE_ERR(conn, ERR_CLSD);
 396       return ERR_CLSD;
 397     }
 398     len = ((struct pbuf *)buf)->tot_len;
 399   }
 400 #endif /* LWIP_TCP */
 401 #if LWIP_TCP && (LWIP_UDP || LWIP_RAW)
 402   else
 403 #endif /* LWIP_TCP && (LWIP_UDP || LWIP_RAW) */
 404 #if (LWIP_UDP || LWIP_RAW)
 405   {
 406     LWIP_ASSERT("buf != NULL", buf != NULL);
 407     len = netbuf_len((struct netbuf *)buf);
 408   }
 409 #endif /* (LWIP_UDP || LWIP_RAW) */
 410
 411 #if LWIP_SO_RCVBUF
 412   SYS_ARCH_DEC(conn->recv_avail, len);
 413 #endif /* LWIP_SO_RCVBUF */
 414   /* Register event with callback */
 415   API_EVENT(conn, NETCONN_EVT_RCVMINUS, len);
 416
 417   LWIP_DEBUGF(API_LIB_DEBUG, ("netconn_recv_data: received %p, len=%"U16_F"\n", buf, len));
 418
 419   *new_buf = buf;
 420   /* don't set conn->last_err: it's only ERR_OK, anyway */
 421   return ERR_OK;
 422 }
 423
 424 /**
 425  * Receive data (in form of a pbuf) from a TCP netconn
 426  *
 427  * @param conn the netconn from which to receive data
 428  * @param new_buf pointer where a new pbuf is stored when received data
 429  * @return ERR_OK if data has been received, an error code otherwise (timeout,
 430  *                memory error or another error)
 431  *         ERR_ARG if conn is not a TCP netconn
 432  */
 433 err_t
 434 netconn_recv_tcp_pbuf(struct netconn *conn, struct pbuf **new_buf)
 435 {
 436   LWIP_ERROR("netconn_recv: invalid conn", (conn != NULL) &&
 437              netconn_type(conn) == NETCONN_TCP, return ERR_ARG;);
 438
 439   return netconn_recv_data(conn, (void **)new_buf);
 440 }
 441
 442 /**
 443  * Receive data (in form of a netbuf containing a packet buffer) from a netconn
 444  *
 445  * @param conn the netconn from which to receive data
 446  * @param new_buf pointer where a new netbuf is stored when received data
 447  * @return ERR_OK if data has been received, an error code otherwise (timeout,
 448  *                memory error or another error)
 449  */
 450 err_t
 451 netconn_recv(struct netconn *conn, struct netbuf **new_buf)
 452 {
 453 #if LWIP_TCP
 454   struct netbuf *buf = NULL;
 455   err_t err;
 456 #endif /* LWIP_TCP */
 457
 458   LWIP_ERROR("netconn_recv: invalid pointer", (new_buf != NULL), return ERR_ARG;);
 459   *new_buf = NULL;
 460   LWIP_ERROR("netconn_recv: invalid conn",    (conn != NULL),    return ERR_ARG;);
 461   LWIP_ERROR("netconn_accept: invalid recvmbox", sys_mbox_valid(&conn->recvmbox), return ERR_CONN;);
 462
 463 #if LWIP_TCP
 464   if (conn->type == NETCONN_TCP) {
 465     struct pbuf *p = NULL;
 466     /* This is not a listening netconn, since recvmbox is set */
 467
 468     buf = (struct netbuf *)memp_malloc(MEMP_NETBUF);
 469     if (buf == NULL) {
 470       NETCONN_SET_SAFE_ERR(conn, ERR_MEM);
 471       return ERR_MEM;
 472     }
 473
 474     err = netconn_recv_data(conn, (void **)&p);
 475     if (err != ERR_OK) {
 476       memp_free(MEMP_NETBUF, buf);
 477       return err;
 478     }
 479     LWIP_ASSERT("p != NULL", p != NULL);
 480
 481     buf->p = p;
 482     buf->ptr = p;
 483     buf->port = 0;
 484     ip_addr_set_any(&buf->addr);
 485     *new_buf = buf;
 486     /* don't set conn->last_err: it's only ERR_OK, anyway */
 487     return ERR_OK;
 488   } else
 489 #endif /* LWIP_TCP */
 490   {
 491 #if (LWIP_UDP || LWIP_RAW)
 492     return netconn_recv_data(conn, (void **)new_buf);
 493 #endif /* (LWIP_UDP || LWIP_RAW) */
 494   }
 495 }
 496
 497 /**
 498  * TCP: update the receive window: by calling this, the application
 499  * tells the stack that it has processed data and is able to accept
 500  * new data.
 501  * ATTENTION: use with care, this is mainly used for sockets!
 502  * Can only be used when calling netconn_set_noautorecved(conn, 1) before.
 503  *
 504  * @param conn the netconn for which to update the receive window
 505  * @param length amount of data processed (ATTENTION: this must be accurate!)
 506  */
 507 void
 508 netconn_recved(struct netconn *conn, u32_t length)
 509 {
 510 #if LWIP_TCP
 511   if ((conn != NULL) && (conn->type == NETCONN_TCP) &&
 512       (netconn_get_noautorecved(conn))) {
 513     struct api_msg msg;
 514     /* Let the stack know that we have taken the data. */
 515     /* TODO: Speedup: Don't block and wait for the answer here
 516        (to prevent multiple thread-switches). */
 517     msg.function = do_recv;
 518     msg.msg.conn = conn;
 519     msg.msg.msg.r.len = length;
 520     /* don't care for the return value of do_recv */
 521     TCPIP_APIMSG(&msg);
 522   }
 523 #else /* LWIP_TCP */
 524   LWIP_UNUSED_ARG(conn);
 525   LWIP_UNUSED_ARG(length);
 526 #endif /* LWIP_TCP */
 527 }
 528
 529 /**
 530  * Send data (in form of a netbuf) to a specific remote IP address and port.
 531  * Only to be used for UDP and RAW netconns (not TCP).
 532  *
 533  * @param conn the netconn over which to send data
 534  * @param buf a netbuf containing the data to send
 535  * @param addr the remote IP address to which to send the data
 536  * @param port the remote port to which to send the data
 537  * @return ERR_OK if data was sent, any other err_t on error
 538  */
 539 err_t
 540 netconn_sendto(struct netconn *conn, struct netbuf *buf, ip_addr_t *addr, u16_t port)
 541 {
 542   if (buf != NULL) {
 543     ip_addr_set(&buf->addr, addr);
 544     buf->port = port;
 545     return netconn_send(conn, buf);
 546   }
 547   return ERR_VAL;
 548 }
 549
 550 /**
 551  * Send data over a UDP or RAW netconn (that is already connected).
 552  *
 553  * @param conn the UDP or RAW netconn over which to send data
 554  * @param buf a netbuf containing the data to send
 555  * @return ERR_OK if data was sent, any other err_t on error
 556  */
 557 err_t
 558 netconn_send(struct netconn *conn, struct netbuf *buf)
 559 {
 560   struct api_msg msg;
 561   err_t err;
 562
 563   LWIP_ERROR("netconn_send: invalid conn",  (conn != NULL), return ERR_ARG;);
 564
 565   LWIP_DEBUGF(API_LIB_DEBUG, ("netconn_send: sending %"U16_F" bytes\n", buf->p->tot_len));
 566   msg.function = do_send;
 567   msg.msg.conn = conn;
 568   msg.msg.msg.b = buf;
 569   err = TCPIP_APIMSG(&msg);
 570
 571   NETCONN_SET_SAFE_ERR(conn, err);
 572   return err;
 573 }
 574
 575 /**
 576  * Send data over a TCP netconn.
 577  *
 578  * @param conn the TCP netconn over which to send data
 579  * @param dataptr pointer to the application buffer that contains the data to send
 580  * @param size size of the application data to send
 581  * @param apiflags combination of following flags :
 582  * - NETCONN_COPY: data will be copied into memory belonging to the stack
 583  * - NETCONN_MORE: for TCP connection, PSH flag will be set on last segment sent
 584  * - NETCONN_DONTBLOCK: only write the data if all dat can be written at once
 585  * @return ERR_OK if data was sent, any other err_t on error
 586  */
 587 err_t
 588 netconn_write(struct netconn *conn, const void *dataptr, size_t size, u8_t apiflags)
 589 {
 590   struct api_msg msg;
 591   err_t err;
 592
 593   LWIP_ERROR("netconn_write: invalid conn",  (conn != NULL), return ERR_ARG;);
 594   LWIP_ERROR("netconn_write: invalid conn->type",  (conn->type == NETCONN_TCP), return ERR_VAL;);
 595   if (size == 0) {
 596     return ERR_OK;
 597   }
 598
 599   /* @todo: for non-blocking write, check if 'size' would ever fit into
 600             snd_queue or snd_buf */
 601   msg.function = do_write;
 602   msg.msg.conn = conn;
 603   msg.msg.msg.w.dataptr = dataptr;
 604   msg.msg.msg.w.apiflags = apiflags;
 605   msg.msg.msg.w.len = size;
 606   /* For locking the core: this _can_ be delayed on low memory/low send buffer,
 607      but if it is, this is done inside api_msg.c:do_write(), so we can use the
 608      non-blocking version here. */
 609   err = TCPIP_APIMSG(&msg);
 610
 611   NETCONN_SET_SAFE_ERR(conn, err);
 612   return err;
 613 }
 614
 615 /**
 616  * Close ot shutdown a TCP netconn (doesn't delete it).
 617  *
 618  * @param conn the TCP netconn to close or shutdown
 619  * @param how fully close or only shutdown one side?
 620  * @return ERR_OK if the netconn was closed, any other err_t on error
 621  */
 622 static err_t
 623 netconn_close_shutdown(struct netconn *conn, u8_t how)
 624 {
 625   struct api_msg msg;
 626   err_t err;
 627
 628   LWIP_ERROR("netconn_close: invalid conn",  (conn != NULL), return ERR_ARG;);
 629
 630   msg.function = do_close;
 631   msg.msg.conn = conn;
 632   /* shutting down both ends is the same as closing */
 633   msg.msg.msg.sd.shut = how;
 634   /* because of the LWIP_TCPIP_CORE_LOCKING implementation of do_close,
 635      don't use TCPIP_APIMSG here */
 636   err = tcpip_apimsg(&msg);
 637
 638   NETCONN_SET_SAFE_ERR(conn, err);
 639   return err;
 640 }
 641
 642 /**
 643  * Close a TCP netconn (doesn't delete it).
 644  *
 645  * @param conn the TCP netconn to close
 646  * @return ERR_OK if the netconn was closed, any other err_t on error
 647  */
 648 err_t
 649 netconn_close(struct netconn *conn)
 650 {
 651   /* shutting down both ends is the same as closing */
 652   return netconn_close_shutdown(conn, NETCONN_SHUT_RDWR);
 653 }
 654
 655 /**
 656  * Shut down one or both sides of a TCP netconn (doesn't delete it).
 657  *
 658  * @param conn the TCP netconn to shut down
 659  * @return ERR_OK if the netconn was closed, any other err_t on error
 660  */
 661 err_t
 662 netconn_shutdown(struct netconn *conn, u8_t shut_rx, u8_t shut_tx)
 663 {
 664   return netconn_close_shutdown(conn, (shut_rx ? NETCONN_SHUT_RD : 0) | (shut_tx ? NETCONN_SHUT_WR : 0));
 665 }
 666
 667 #if LWIP_IGMP
 668 /**
 669  * Join multicast groups for UDP netconns.
 670  *
 671  * @param conn the UDP netconn for which to change multicast addresses
 672  * @param multiaddr IP address of the multicast group to join or leave
 673  * @param netif_addr the IP address of the network interface on which to send
 674  *                  the igmp message
 675  * @param join_or_leave flag whether to send a join- or leave-message
 676  * @return ERR_OK if the action was taken, any err_t on error
 677  */
 678 err_t
 679 netconn_join_leave_group(struct netconn *conn,
 680                          ip_addr_t *multiaddr,
 681                          ip_addr_t *netif_addr,
 682                          enum netconn_igmp join_or_leave)
 683 {
 684   struct api_msg msg;
 685   err_t err;
 686
 687   LWIP_ERROR("netconn_join_leave_group: invalid conn",  (conn != NULL), return ERR_ARG;);
 688
 689   msg.function = do_join_leave_group;
 690   msg.msg.conn = conn;
 691   msg.msg.msg.jl.multiaddr = multiaddr;
 692   msg.msg.msg.jl.netif_addr = netif_addr;
 693   msg.msg.msg.jl.join_or_leave = join_or_leave;
 694   err = TCPIP_APIMSG(&msg);
 695
 696   NETCONN_SET_SAFE_ERR(conn, err);
 697   return err;
 698 }
 699 #endif /* LWIP_IGMP */
 700
 701 #if LWIP_DNS
 702 /**
 703  * Execute a DNS query, only one IP address is returned
 704  *
 705  * @param name a string representation of the DNS host name to query
 706  * @param addr a preallocated ip_addr_t where to store the resolved IP address
 707  * @return ERR_OK: resolving succeeded
 708  *         ERR_MEM: memory error, try again later
 709  *         ERR_ARG: dns client not initialized or invalid hostname
 710  *         ERR_VAL: dns server response was invalid
 711  */
 712 err_t
 713 netconn_gethostbyname(const char *name, ip_addr_t *addr)
 714 {
 715   struct dns_api_msg msg;
 716   err_t err;
 717   sys_sem_t sem;
 718
 719   LWIP_ERROR("netconn_gethostbyname: invalid name", (name != NULL), return ERR_ARG;);
 720   LWIP_ERROR("netconn_gethostbyname: invalid addr", (addr != NULL), return ERR_ARG;);
 721
 722   err = sys_sem_new(&sem, 0);
 723   if (err != ERR_OK) {
 724     return err;
 725   }
 726
 727   msg.name = name;
 728   msg.addr = addr;
 729   msg.err = &err;
 730   msg.sem = &sem;
 731
 732   tcpip_callback(do_gethostbyname, &msg);
 733   sys_sem_wait(&sem);
 734   sys_sem_free(&sem);
 735
 736   return err;
 737 }
 738 #endif /* LWIP_DNS*/
 739
 740 #endif /* LWIP_NETCONN */