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| <div class="section" id="network-interfaces"> |
| <h1>Network Interfaces<a class="headerlink" href="#network-interfaces" title="Permalink to this headline">¶</a></h1> |
| <p>NuttX supports a BSD-compatible socket interface layer. These socket |
| interface can be enabled by settings in the architecture configuration |
| file. Those socket APIs are discussed in |
| the following paragraphs.</p> |
| <blockquote> |
| <div><ul class="simple"> |
| <li><p><a class="reference internal" href="#c.socket" title="socket"><code class="xref c c-func docutils literal notranslate"><span class="pre">socket()</span></code></a></p></li> |
| <li><p><a class="reference internal" href="#c.bind" title="bind"><code class="xref c c-func docutils literal notranslate"><span class="pre">bind()</span></code></a></p></li> |
| <li><p><a class="reference internal" href="#c.connect" title="connect"><code class="xref c c-func docutils literal notranslate"><span class="pre">connect()</span></code></a></p></li> |
| <li><p><a class="reference internal" href="#c.listen" title="listen"><code class="xref c c-func docutils literal notranslate"><span class="pre">listen()</span></code></a></p></li> |
| <li><p><a class="reference internal" href="#c.accept" title="accept"><code class="xref c c-func docutils literal notranslate"><span class="pre">accept()</span></code></a></p></li> |
| <li><p><a class="reference internal" href="#c.send" title="send"><code class="xref c c-func docutils literal notranslate"><span class="pre">send()</span></code></a></p></li> |
| <li><p><a class="reference internal" href="#c.sendto" title="sendto"><code class="xref c c-func docutils literal notranslate"><span class="pre">sendto()</span></code></a></p></li> |
| <li><p><a class="reference internal" href="#c.recv" title="recv"><code class="xref c c-func docutils literal notranslate"><span class="pre">recv()</span></code></a></p></li> |
| <li><p><a class="reference internal" href="#c.recvfrom" title="recvfrom"><code class="xref c c-func docutils literal notranslate"><span class="pre">recvfrom()</span></code></a></p></li> |
| <li><p><a class="reference internal" href="#c.setsockopt" title="setsockopt"><code class="xref c c-func docutils literal notranslate"><span class="pre">setsockopt()</span></code></a></p></li> |
| <li><p><a class="reference internal" href="#c.getsockopt" title="getsockopt"><code class="xref c c-func docutils literal notranslate"><span class="pre">getsockopt()</span></code></a></p></li> |
| </ul> |
| </div></blockquote> |
| <dl class="c function"> |
| <dt id="c.socket"> |
| <span class="pre">int</span> <code class="sig-name descname"><span class="pre">socket</span></code><span class="sig-paren">(</span><span class="pre">int</span> <em><span class="pre">domain</span></em>, <span class="pre">int</span> <em><span class="pre">type</span></em>, <span class="pre">int</span> <em><span class="pre">protocol</span></em><span class="sig-paren">)</span><span class="pre">;</span><a class="headerlink" href="#c.socket" title="Permalink to this definition">¶</a><br /></dt> |
| <dd><p>Creates an endpoint for communication and |
| returns a descriptor.</p> |
| <dl class="field-list simple"> |
| <dt class="field-odd">Parameters</dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>domain</strong> – (see sys/socket.h)</p></li> |
| <li><p><strong>type</strong> – (see sys/socket.h)</p></li> |
| <li><p><strong>protocol</strong> – (see sys/socket.h)</p></li> |
| </ul> |
| </dd> |
| <dt class="field-even">Returns</dt> |
| <dd class="field-even"><p><p>0 on success; -1 on error with |
| <code class="docutils literal notranslate"><span class="pre">errno</span></code> set appropriately:</p> |
| <ul class="simple"> |
| <li><p><code class="docutils literal notranslate"><span class="pre">EACCES</span></code>. Permission to create a socket of the specified type |
| and/or protocol is denied.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">EAFNOSUPPORT</span></code>. The implementation does not support the specified |
| address family.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">EINVAL</span></code>. Unknown protocol, or protocol family not available.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">EMFILE</span></code>. Process file table overflow.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">ENFILE</span></code> The system limit on the total number of open files has |
| been reached.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">ENOBUFS</span></code> or <code class="docutils literal notranslate"><span class="pre">ENOMEM</span></code>. Insufficient memory is available. The |
| socket cannot be created until sufficient resources are freed.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">EPROTONOSUPPORT</span></code>. The protocol type or the specified protocol is |
| not supported within this domain.</p></li> |
| </ul> |
| </p> |
| </dd> |
| </dl> |
| </dd></dl> |
| |
| <dl class="c function"> |
| <dt id="c.bind"> |
| <span class="pre">int</span> <code class="sig-name descname"><span class="pre">bind</span></code><span class="sig-paren">(</span><span class="pre">int</span> <em><span class="pre">sockfd</span></em>, <em class="property"><span class="pre">const</span></em> <em class="property"><span class="pre">struct</span></em> <span class="pre">sockaddr</span> <span class="pre">*</span><em><span class="pre">addr</span></em>, <span class="pre">socklen_t</span> <em><span class="pre">addrlen</span></em><span class="sig-paren">)</span><a class="headerlink" href="#c.bind" title="Permalink to this definition">¶</a><br /></dt> |
| <dd><p>Gives the socket sockfd the local address |
| <code class="docutils literal notranslate"><span class="pre">addr</span></code>. <code class="docutils literal notranslate"><span class="pre">addr</span></code> is <code class="docutils literal notranslate"><span class="pre">addrlen</span></code> bytes long. Traditionally, this is |
| called “assigning a name to a socket.” When a socket is created with |
| <code class="docutils literal notranslate"><span class="pre">socket()</span></code>, it exists in a name space (address family) but has no name |
| assigned.</p> |
| <dl class="field-list simple"> |
| <dt class="field-odd">Parameters</dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>sockfd</strong> – Socket descriptor from socket.</p></li> |
| <li><p><strong>addr</strong> – Socket local address.</p></li> |
| <li><p><strong>addrlen</strong> – Length of <code class="docutils literal notranslate"><span class="pre">addr</span></code>.</p></li> |
| </ul> |
| </dd> |
| <dt class="field-even">Returns</dt> |
| <dd class="field-even"><p>0 on success; -1 on error with <code class="docutils literal notranslate"><span class="pre">errno</span></code> set appropriately: |
| - <code class="docutils literal notranslate"><span class="pre">EACCES</span></code> The address is protected, and the user is not the |
| superuser. |
| - <code class="docutils literal notranslate"><span class="pre">EADDRINUSE</span></code> The given address is already in use. |
| - <code class="docutils literal notranslate"><span class="pre">EBADF</span></code> <code class="docutils literal notranslate"><span class="pre">sockfd</span></code> is not a valid descriptor. |
| - <code class="docutils literal notranslate"><span class="pre">EINVAL</span></code> The socket is already bound to an address. |
| - <code class="docutils literal notranslate"><span class="pre">ENOTSOCK</span></code> <code class="docutils literal notranslate"><span class="pre">sockfd</span></code> is a descriptor for a file, not a socket.</p> |
| </dd> |
| </dl> |
| </dd></dl> |
| |
| <dl class="c function"> |
| <dt id="c.connect"> |
| <span class="pre">int</span> <code class="sig-name descname"><span class="pre">connect</span></code><span class="sig-paren">(</span><span class="pre">int</span> <em><span class="pre">sockfd</span></em>, <em class="property"><span class="pre">const</span></em> <em class="property"><span class="pre">struct</span></em> <span class="pre">sockaddr</span> <span class="pre">*</span><em><span class="pre">addr</span></em>, <span class="pre">socklen_t</span> <em><span class="pre">addrlen</span></em><span class="sig-paren">)</span><span class="pre">;</span><a class="headerlink" href="#c.connect" title="Permalink to this definition">¶</a><br /></dt> |
| <dd><p><code class="docutils literal notranslate"><span class="pre">connect()</span></code> connects the socket referred to by the |
| file descriptor <code class="docutils literal notranslate"><span class="pre">sockfd</span></code> to the address specified by <code class="docutils literal notranslate"><span class="pre">addr</span></code>. The |
| <code class="docutils literal notranslate"><span class="pre">addrlen</span></code> argument specifies the size of <code class="docutils literal notranslate"><span class="pre">addr</span></code>. The format of the |
| address in <code class="docutils literal notranslate"><span class="pre">addr</span></code> is determined by the address space of the socket |
| sockfd. If the socket sockfd is of type SOCK_DGRAM then <code class="docutils literal notranslate"><span class="pre">addr</span></code> is the |
| address to which datagrams are sent by default, and the only address |
| from which datagrams are received. If the socket is of type SOCK_STREAM |
| or SOCK_SEQPACKET, this call attempts to make a connection to the socket |
| that is bound to the address specified by <code class="docutils literal notranslate"><span class="pre">addr</span></code>. Generally, |
| connection-based protocol sockets may successfully <code class="docutils literal notranslate"><span class="pre">connect()</span></code> only |
| once; connectionless protocol sockets may use <code class="docutils literal notranslate"><span class="pre">connect()</span></code> multiple |
| times to change their association. Connectionless sockets may dissolve |
| the association by connecting to an address with the sa_family member of |
| sockaddr set to AF_UNSPEC.</p> |
| <p><strong>Input Parameters:</strong></p> |
| <ul class="simple"> |
| <li><p><code class="docutils literal notranslate"><span class="pre">sockfd</span></code>: Socket descriptor returned by <code class="docutils literal notranslate"><span class="pre">socket()</span></code></p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">addr</span></code>: Server address (form depends on type of socket)</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">addrlen</span></code>: Length of actual <code class="docutils literal notranslate"><span class="pre">addr</span></code></p></li> |
| </ul> |
| <p><strong>Returned Value:</strong> 0 on success; -1 on error with |
| <code class="docutils literal notranslate"><span class="pre">`errno</span></code> <#ErrnoAccess>`__ set appropriately:</p> |
| <p><code class="docutils literal notranslate"><span class="pre">EACCES</span></code> or EPERM: The user tried to connect to a broadcast address |
| without having the socket broadcast flag enabled or the connection |
| request failed because of a local firewall rule.</p> |
| <p><code class="docutils literal notranslate"><span class="pre">EADDRINUSE</span></code> Local address is already in use.</p> |
| <p><code class="docutils literal notranslate"><span class="pre">EAFNOSUPPORT</span></code> The passed address didn’t have the correct address |
| family in its sa_family field.</p> |
| <p><code class="docutils literal notranslate"><span class="pre">EAGAIN</span></code> No more free local ports or insufficient entries in the |
| routing cache. For PF_INET.</p> |
| <p><code class="docutils literal notranslate"><span class="pre">EALREADY</span></code> The socket is non-blocking and a previous connection |
| attempt has not yet been completed.</p> |
| <p><code class="docutils literal notranslate"><span class="pre">EBADF</span></code> The file descriptor is not a valid index in the descriptor |
| table.</p> |
| <p><code class="docutils literal notranslate"><span class="pre">ECONNREFUSED</span></code> No one listening on the remote address.</p> |
| <p><code class="docutils literal notranslate"><span class="pre">EFAULT</span></code> The socket structure address is outside the user’s address |
| space.</p> |
| <p><code class="docutils literal notranslate"><span class="pre">EINPROGRESS</span></code> The socket is non-blocking and the connection cannot be |
| completed immediately.</p> |
| <p><code class="docutils literal notranslate"><span class="pre">EINTR</span></code> The system call was interrupted by a signal that was caught.</p> |
| <p><code class="docutils literal notranslate"><span class="pre">EISCONN</span></code> The socket is already connected.</p> |
| <p><code class="docutils literal notranslate"><span class="pre">ENETUNREACH</span></code> Network is unreachable.</p> |
| <p><code class="docutils literal notranslate"><span class="pre">ENOTSOCK</span></code> The file descriptor is not associated with a socket.</p> |
| <p><code class="docutils literal notranslate"><span class="pre">ETIMEDOUT</span></code> Timeout while attempting connection. The server may be too |
| busy to accept new connections.</p> |
| </dd></dl> |
| |
| <dl class="c function"> |
| <dt id="c.listen"> |
| <span class="pre">int</span> <code class="sig-name descname"><span class="pre">listen</span></code><span class="sig-paren">(</span><span class="pre">int</span> <em><span class="pre">sockfd</span></em>, <span class="pre">int</span> <em><span class="pre">backlog</span></em><span class="sig-paren">)</span><span class="pre">;</span><a class="headerlink" href="#c.listen" title="Permalink to this definition">¶</a><br /></dt> |
| <dd><p>To accept connections, a socket is first created with |
| <code class="docutils literal notranslate"><span class="pre">socket()</span></code>, a willingness to accept incoming connections and a queue |
| limit for incoming connections are specified with <code class="docutils literal notranslate"><span class="pre">listen()</span></code>, and then |
| the connections are accepted with <code class="docutils literal notranslate"><span class="pre">accept()</span></code>. The <code class="docutils literal notranslate"><span class="pre">listen()</span></code> call |
| applies only to sockets of type <code class="docutils literal notranslate"><span class="pre">SOCK_STREAM</span></code> or <code class="docutils literal notranslate"><span class="pre">SOCK_SEQPACKET</span></code>.</p> |
| <p><strong>Input Parameters:</strong></p> |
| <ul class="simple"> |
| <li><p><code class="docutils literal notranslate"><span class="pre">sockfd</span></code>: Socket descriptor of the bound socket.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">backlog</span></code>: The maximum length the queue of pending connections may |
| grow. If a connection request arrives with the queue full, the client |
| may receive an error with an indication of ECONNREFUSED or, if the |
| underlying protocol supports retransmission, the request may be |
| ignored so that retries succeed.</p></li> |
| </ul> |
| <p><strong>Returned Value:</strong> On success, zero is returned. On error, -1 is |
| returned, and <code class="docutils literal notranslate"><span class="pre">`errno</span></code> <#ErrnoAccess>`__ is set appropriately.</p> |
| <ul class="simple"> |
| <li><p><code class="docutils literal notranslate"><span class="pre">EADDRINUSE</span></code>: Another socket is already listening on the same port.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">EBADF</span></code>: The argument <code class="docutils literal notranslate"><span class="pre">sockfd</span></code> is not a valid descriptor.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">ENOTSOCK</span></code>: The argument <code class="docutils literal notranslate"><span class="pre">sockfd</span></code> is not a socket.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">EOPNOTSUPP</span></code>: The socket is not of a type that supports the listen |
| operation.</p></li> |
| </ul> |
| </dd></dl> |
| |
| <dl class="c function"> |
| <dt id="c.accept"> |
| <span class="pre">int</span> <code class="sig-name descname"><span class="pre">accept</span></code><span class="sig-paren">(</span><span class="pre">int</span> <em><span class="pre">sockfd</span></em>, <em class="property"><span class="pre">struct</span></em> <span class="pre">sockaddr</span> <span class="pre">*</span><em><span class="pre">addr</span></em>, <span class="pre">socklen_t</span> <span class="pre">*</span><em><span class="pre">addrlen</span></em><span class="sig-paren">)</span><span class="pre">;</span><a class="headerlink" href="#c.accept" title="Permalink to this definition">¶</a><br /></dt> |
| <dd><p>The <code class="docutils literal notranslate"><span class="pre">accept()</span></code> function is used with connection-based |
| socket types (<code class="docutils literal notranslate"><span class="pre">SOCK_STREAM</span></code>, <code class="docutils literal notranslate"><span class="pre">SOCK_SEQPACKET</span></code> and <code class="docutils literal notranslate"><span class="pre">SOCK_RDM</span></code>). It |
| extracts the first connection request on the queue of pending |
| connections, creates a new connected socket with most of the same |
| properties as <code class="docutils literal notranslate"><span class="pre">sockfd</span></code>, and allocates a new socket descriptor for the |
| socket, which is returned. The newly created socket is no longer in the |
| listening state. The original socket <code class="docutils literal notranslate"><span class="pre">sockfd</span></code> is unaffected by this |
| call. Per file descriptor flags are not inherited across an accept.</p> |
| <p>The <code class="docutils literal notranslate"><span class="pre">sockfd</span></code> argument is a socket descriptor that has been created |
| with <code class="docutils literal notranslate"><span class="pre">socket()</span></code>, bound to a local address with <code class="docutils literal notranslate"><span class="pre">bind()</span></code>, and is |
| listening for connections after a call to <code class="docutils literal notranslate"><span class="pre">listen()</span></code>.</p> |
| <p>On return, the <code class="docutils literal notranslate"><span class="pre">addr</span></code> structure is filled in with the address of the |
| connecting entity. The <code class="docutils literal notranslate"><span class="pre">addrlen</span></code> argument initially contains the size |
| of the structure pointed to by <code class="docutils literal notranslate"><span class="pre">addr</span></code>; on return it will contain the |
| actual length of the address returned.</p> |
| <p>If no pending connections are present on the queue, and the socket is |
| not marked as non-blocking, accept blocks the caller until a connection |
| is present. If the socket is marked non-blocking and no pending |
| connections are present on the queue, accept returns <code class="docutils literal notranslate"><span class="pre">EAGAIN</span></code>.</p> |
| <p><strong>Input Parameters:</strong></p> |
| <ul class="simple"> |
| <li><p><code class="docutils literal notranslate"><span class="pre">sockfd</span></code>: Socket descriptor of the listening socket.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">addr</span></code>: Receives the address of the connecting client.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">addrlen</span></code>: Input: allocated size of <code class="docutils literal notranslate"><span class="pre">addr</span></code>, Return: returned size |
| of <code class="docutils literal notranslate"><span class="pre">addr</span></code>.</p></li> |
| </ul> |
| <p><strong>Returned Value:</strong> Returns -1 on error. If it succeeds, it returns a |
| non-negative integer that is a descriptor for the accepted socket.</p> |
| <ul class="simple"> |
| <li><p><code class="docutils literal notranslate"><span class="pre">EAGAIN</span></code> or <code class="docutils literal notranslate"><span class="pre">EWOULDBLOCK</span></code>: The socket is marked non-blocking and |
| no connections are present to be accepted.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">EBADF</span></code>: The descriptor is invalid.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">ENOTSOCK</span></code>: The descriptor references a file, not a socket.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">EOPNOTSUPP</span></code>: The referenced socket is not of type <code class="docutils literal notranslate"><span class="pre">SOCK_STREAM</span></code>.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">EINTR</span></code>: The system call was interrupted by a signal that was |
| caught before a valid connection arrived.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">ECONNABORTED</span></code>: A connection has been aborted.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">EINVAL</span></code>: Socket is not listening for connections.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">EMFILE</span></code>: The per-process limit of open file descriptors has been |
| reached.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">ENFILE</span></code>: The system maximum for file descriptors has been reached.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">EFAULT</span></code>: The addr parameter is not in a writable part of the user |
| address space.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">ENOBUFS</span></code> or <code class="docutils literal notranslate"><span class="pre">ENOMEM</span></code>: Not enough free memory.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">EPROTO</span></code>: Protocol error.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">EPERM</span></code>: Firewall rules forbid connection.</p></li> |
| </ul> |
| </dd></dl> |
| |
| <dl class="c function"> |
| <dt id="c.send"> |
| <span class="pre">ssize_t</span> <code class="sig-name descname"><span class="pre">send</span></code><span class="sig-paren">(</span><span class="pre">int</span> <em><span class="pre">sockfd</span></em>, <em class="property"><span class="pre">const</span></em> <span class="pre">void</span> <span class="pre">*</span><em><span class="pre">buf</span></em>, <a class="reference internal" href="structures.html#c.size_t" title="size_t"><span class="pre">size_t</span></a> <em><span class="pre">len</span></em>, <span class="pre">int</span> <em><span class="pre">flags</span></em><span class="sig-paren">)</span><span class="pre">;</span><a class="headerlink" href="#c.send" title="Permalink to this definition">¶</a><br /></dt> |
| <dd><p>The <code class="docutils literal notranslate"><span class="pre">send()</span></code> call may be used only when the socket is |
| in a connected state (so that the intended recipient is known). The only |
| difference between <code class="docutils literal notranslate"><span class="pre">send()</span></code> and <code class="docutils literal notranslate"><span class="pre">write()</span></code> is the presence of |
| <code class="docutils literal notranslate"><span class="pre">flags</span></code>. With <code class="docutils literal notranslate"><span class="pre">zero</span></code> flags parameter, <code class="docutils literal notranslate"><span class="pre">send()</span></code> is equivalent to |
| <code class="docutils literal notranslate"><span class="pre">write()</span></code>. Also, <code class="docutils literal notranslate"><span class="pre">send(s,buf,len,flags)</span></code> is equivalent to |
| <code class="docutils literal notranslate"><span class="pre">sendto(s,buf,len,flags,NULL,0)</span></code>.</p> |
| <p><strong>Input Parameters:</strong></p> |
| <ul class="simple"> |
| <li><p><code class="docutils literal notranslate"><span class="pre">sockfd</span></code>: Socket descriptor of socket</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">buf</span></code>: Data to send</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">len</span></code>: Length of data to send</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">flags</span></code>: Send flags</p></li> |
| </ul> |
| <p><strong>Returned Value:</strong> See <code class="docutils literal notranslate"><span class="pre">`sendto()</span></code> <#sendto>`__.</p> |
| </dd></dl> |
| |
| <dl class="c function"> |
| <dt id="c.sendto"> |
| <span class="pre">ssize_t</span> <code class="sig-name descname"><span class="pre">sendto</span></code><span class="sig-paren">(</span><span class="pre">int</span> <em><span class="pre">sockfd</span></em>, <em class="property"><span class="pre">const</span></em> <span class="pre">void</span> <span class="pre">*</span><em><span class="pre">buf</span></em>, <a class="reference internal" href="structures.html#c.size_t" title="size_t"><span class="pre">size_t</span></a> <em><span class="pre">len</span></em>, <span class="pre">int</span> <em><span class="pre">flags</span></em>, <em class="property"><span class="pre">const</span></em> <em class="property"><span class="pre">struct</span></em> <span class="pre">sockaddr</span> <span class="pre">*</span><em><span class="pre">to</span></em>, <span class="pre">socklen_t</span> <em><span class="pre">tolen</span></em><span class="sig-paren">)</span><span class="pre">;</span><a class="headerlink" href="#c.sendto" title="Permalink to this definition">¶</a><br /></dt> |
| <dd><p>If <code class="docutils literal notranslate"><span class="pre">sendto()</span></code> is used on a connection-mode |
| (SOCK_STREAM, SOCK_SEQPACKET) socket, the parameters to and tolen are |
| ignored (and the error EISCONN may be returned when they are not NULL |
| and 0), and the error ENOTCONN is returned when the socket was not |
| actually connected.</p> |
| <p><strong>Input Parameters:</strong></p> |
| <ul class="simple"> |
| <li><p><code class="docutils literal notranslate"><span class="pre">sockfd</span></code>: Socket descriptor of socket</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">buf</span></code>: Data to send</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">len</span></code>: Length of data to send</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">flags</span></code>: Send flags</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">to</span></code>: Address of recipient</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">tolen</span></code>: The length of the address structure</p></li> |
| </ul> |
| <p><strong>Returned Value:</strong> On success, returns the number of characters sent. |
| On error, -1 is returned, and <code class="docutils literal notranslate"><span class="pre">`errno</span></code> <#ErrnoAccess>`__ is set |
| appropriately:</p> |
| <ul class="simple"> |
| <li><p><code class="docutils literal notranslate"><span class="pre">EAGAIN</span></code> or <code class="docutils literal notranslate"><span class="pre">EWOULDBLOCK</span></code>. The socket is marked non-blocking and |
| the requested operation would block.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">EBADF</span></code>. An invalid descriptor was specified.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">ECONNRESET</span></code>. Connection reset by peer.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">EDESTADDRREQ</span></code>. The socket is not connection-mode, and no peer |
| address is set.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">EFAULT</span></code>. An invalid user space address was specified for a |
| parameter.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">EINTR</span></code>. A signal occurred before any data was transmitted.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">EINVAL</span></code>. Invalid argument passed.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">EISCONN</span></code>. The connection-mode socket was connected already but a |
| recipient was specified. (Now either this error is returned, or the |
| recipient specification is ignored.)</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">EMSGSIZE</span></code>. The socket type requires that message be sent |
| atomically, and the size of the message to be sent made this |
| impossible.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">ENOBUFS</span></code>. The output queue for a network interface was full. This |
| generally indicates that the interface has stopped sending, but may |
| be caused by transient congestion.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">ENOMEM</span></code>. No memory available.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">ENOTCONN</span></code>. The socket is not connected, and no target has been |
| given.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">ENOTSOCK</span></code>. The argument s is not a socket.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">EOPNOTSUPP</span></code>. Some bit in the flags argument is inappropriate for |
| the socket type.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">EPIPE</span></code>. The local end has been shut down on a connection oriented |
| socket. In this case the process will also receive a SIGPIPE unless |
| MSG_NOSIGNAL is set.</p></li> |
| </ul> |
| </dd></dl> |
| |
| <dl class="c function"> |
| <dt id="c.recv"> |
| <span class="pre">ssize_t</span> <code class="sig-name descname"><span class="pre">recv</span></code><span class="sig-paren">(</span><span class="pre">int</span> <em><span class="pre">sockfd</span></em>, <span class="pre">void</span> <span class="pre">*</span><em><span class="pre">buf</span></em>, <a class="reference internal" href="structures.html#c.size_t" title="size_t"><span class="pre">size_t</span></a> <em><span class="pre">len</span></em>, <span class="pre">int</span> <em><span class="pre">flags</span></em><span class="sig-paren">)</span><span class="pre">;</span><a class="headerlink" href="#c.recv" title="Permalink to this definition">¶</a><br /></dt> |
| <dd><p>The <code class="docutils literal notranslate"><span class="pre">recv()</span></code> call is identical to |
| <code class="docutils literal notranslate"><span class="pre">`recvfrom()</span></code> <#recvfrom>`__ with a NULL <code class="docutils literal notranslate"><span class="pre">from</span></code> parameter.</p> |
| <p><strong>Input Parameters:</strong></p> |
| <ul class="simple"> |
| <li><p>sockfd: Socket descriptor of socket</p></li> |
| <li><p>buf: Buffer to receive data</p></li> |
| <li><p>len: Length of buffer</p></li> |
| <li><p>flags: Receive flags</p></li> |
| </ul> |
| <p><strong>Returned Value:</strong> See <code class="docutils literal notranslate"><span class="pre">`recvfrom()</span></code> <#recvfrom>`__.</p> |
| </dd></dl> |
| |
| <dl class="c function"> |
| <dt id="c.recvfrom"> |
| <span class="pre">ssize_t</span> <code class="sig-name descname"><span class="pre">recvfrom</span></code><span class="sig-paren">(</span><span class="pre">int</span> <em><span class="pre">sockfd</span></em>, <span class="pre">void</span> <span class="pre">*</span><em><span class="pre">buf</span></em>, <a class="reference internal" href="structures.html#c.size_t" title="size_t"><span class="pre">size_t</span></a> <em><span class="pre">len</span></em>, <span class="pre">int</span> <em><span class="pre">flags</span></em>, <em class="property"><span class="pre">struct</span></em> <span class="pre">sockaddr</span> <span class="pre">*</span><em><span class="pre">from</span></em>, <span class="pre">socklen_t</span> <span class="pre">*</span><em><span class="pre">fromlen</span></em><span class="sig-paren">)</span><span class="pre">;</span><a class="headerlink" href="#c.recvfrom" title="Permalink to this definition">¶</a><br /></dt> |
| <dd><p><code class="docutils literal notranslate"><span class="pre">recvfrom()</span></code> receives messages from a socket, and may |
| be used to receive data on a socket whether or not it is |
| connection-oriented.</p> |
| <p>If <code class="docutils literal notranslate"><span class="pre">from</span></code> is not NULL, and the underlying protocol provides the source |
| address, this source address is filled in. The argument <code class="docutils literal notranslate"><span class="pre">fromlen</span></code> |
| initialized to the size of the buffer associated with <code class="docutils literal notranslate"><span class="pre">from</span></code>, and |
| modified on return to indicate the actual size of the address stored |
| there.</p> |
| <p><strong>Input Parameters:</strong></p> |
| <ul class="simple"> |
| <li><p><code class="docutils literal notranslate"><span class="pre">sockfd</span></code>: Socket descriptor of socket.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">buf</span></code>: Buffer to receive data.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">len</span></code>: Length of buffer.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">flags</span></code>: Receive flags.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">from</span></code>: Address of source.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">fromlen</span></code>: The length of the address structure.</p></li> |
| </ul> |
| <p><strong>Returned Value:</strong> On success, returns the number of characters sent. |
| If no data is available to be received and the peer has performed an |
| orderly shutdown, recv() will return 0. Otherwise, on errors, -1 is |
| returned, and <code class="docutils literal notranslate"><span class="pre">`errno</span></code> <#ErrnoAccess>`__ is set appropriately:</p> |
| <ul class="simple"> |
| <li><p><code class="docutils literal notranslate"><span class="pre">EAGAIN</span></code>. The socket is marked non-blocking and the receive |
| operation would block, or a receive timeout had been set and the |
| timeout expired before data was received.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">EBADF</span></code>. The argument <code class="docutils literal notranslate"><span class="pre">sockfd</span></code> is an invalid descriptor.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">ECONNREFUSED</span></code>. A remote host refused to allow the network |
| connection (typically because it is not running the requested |
| service).</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">EFAULT</span></code>. The receive buffer pointer(s) point outside the process’s |
| address space.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">EINTR</span></code>. The receive was interrupted by delivery of a signal before |
| any data were available.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">EINVAL</span></code>. Invalid argument passed.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">ENOMEM</span></code>. Could not allocate memory.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">ENOTCONN</span></code>. The socket is associated with a connection-oriented |
| protocol and has not been connected.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">ENOTSOCK</span></code>. The argument <code class="docutils literal notranslate"><span class="pre">sockfd</span></code> does not refer to a socket.</p></li> |
| </ul> |
| </dd></dl> |
| |
| <dl class="c function"> |
| <dt id="c.setsockopt"> |
| <span class="pre">int</span> <code class="sig-name descname"><span class="pre">setsockopt</span></code><span class="sig-paren">(</span><span class="pre">int</span> <em><span class="pre">sockfd</span></em>, <span class="pre">int</span> <em><span class="pre">level</span></em>, <span class="pre">int</span> <em><span class="pre">option</span></em>, <em class="property"><span class="pre">const</span></em> <span class="pre">void</span> <span class="pre">*</span><em><span class="pre">value</span></em>, <span class="pre">socklen_t</span> <em><span class="pre">value_len</span></em><span class="sig-paren">)</span><span class="pre">;</span><a class="headerlink" href="#c.setsockopt" title="Permalink to this definition">¶</a><br /></dt> |
| <dd><p><code class="docutils literal notranslate"><span class="pre">setsockopt()</span></code> sets the option specified by the |
| <code class="docutils literal notranslate"><span class="pre">option</span></code> argument, at the protocol level specified by the <code class="docutils literal notranslate"><span class="pre">level</span></code> |
| argument, to the value pointed to by the <code class="docutils literal notranslate"><span class="pre">value</span></code> argument for the |
| socket associated with the file descriptor specified by the <code class="docutils literal notranslate"><span class="pre">sockfd</span></code> |
| argument.</p> |
| <p>The <code class="docutils literal notranslate"><span class="pre">level</span></code> argument specifies the protocol level of the option. To |
| set options at the socket level, specify the level argument as |
| SOL_SOCKET.</p> |
| <p>See <code class="docutils literal notranslate"><span class="pre">sys/socket.h</span></code> for a complete list of values for the <code class="docutils literal notranslate"><span class="pre">option</span></code> |
| argument.</p> |
| <p><strong>Input Parameters:</strong></p> |
| <ul class="simple"> |
| <li><p><code class="docutils literal notranslate"><span class="pre">sockfd</span></code>: Socket descriptor of socket</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">level</span></code>: Protocol level to set the option</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">option</span></code>: identifies the option to set</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">value</span></code>: Points to the argument value</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">value_len</span></code>: The length of the argument value</p></li> |
| </ul> |
| <p><strong>Returned Value:</strong> On success, returns the number of characters sent. |
| On error, -1 is returned, and <code class="docutils literal notranslate"><span class="pre">`errno</span></code> <#ErrnoAccess>`__ is set |
| appropriately:</p> |
| <ul class="simple"> |
| <li><p><code class="docutils literal notranslate"><span class="pre">BADF</span></code>. The <code class="docutils literal notranslate"><span class="pre">sockfd</span></code> argument is not a valid socket descriptor.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">DOM</span></code>. The send and receive timeout values are too big to fit into |
| the timeout fields in the socket structure.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">INVAL</span></code>. The specified option is invalid at the specified socket |
| <code class="docutils literal notranslate"><span class="pre">level</span></code> or the socket has been shut down.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">ISCONN</span></code>. The socket is already connected, and a specified option |
| cannot be set while the socket is connected.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">NOPROTOOPT</span></code>. The <code class="docutils literal notranslate"><span class="pre">option</span></code> is not supported by the protocol.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">NOTSOCK</span></code>. The <code class="docutils literal notranslate"><span class="pre">sockfd</span></code> argument does not refer to a socket.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">NOMEM</span></code>. There was insufficient memory available for the operation |
| to complete.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">NOBUFS</span></code>. Insufficient resources are available in the system to |
| complete the call.</p></li> |
| </ul> |
| </dd></dl> |
| |
| <dl class="c function"> |
| <dt id="c.getsockopt"> |
| <span class="pre">int</span> <code class="sig-name descname"><span class="pre">getsockopt</span></code><span class="sig-paren">(</span><span class="pre">int</span> <em><span class="pre">sockfd</span></em>, <span class="pre">int</span> <em><span class="pre">level</span></em>, <span class="pre">int</span> <em><span class="pre">option</span></em>, <span class="pre">void</span> <span class="pre">*</span><em><span class="pre">value</span></em>, <span class="pre">socklen_t</span> <span class="pre">*</span><em><span class="pre">value_len</span></em><span class="sig-paren">)</span><span class="pre">;</span><a class="headerlink" href="#c.getsockopt" title="Permalink to this definition">¶</a><br /></dt> |
| <dd><p><code class="docutils literal notranslate"><span class="pre">getsockopt()</span></code> retrieve those value for the option |
| specified by the <code class="docutils literal notranslate"><span class="pre">option</span></code> argument for the socket specified by the |
| <code class="docutils literal notranslate"><span class="pre">sockfd</span></code> argument. If the size of the option value is greater than |
| <code class="docutils literal notranslate"><span class="pre">value_len</span></code>, the value stored in the object pointed to by the |
| <code class="docutils literal notranslate"><span class="pre">value</span></code> argument will be silently truncated. Otherwise, the length |
| pointed to by the <code class="docutils literal notranslate"><span class="pre">value_len</span></code> argument will be modified to indicate |
| the actual length of the <code class="docutils literal notranslate"><span class="pre">value</span></code>.</p> |
| <p>The <code class="docutils literal notranslate"><span class="pre">level</span></code> argument specifies the protocol level of the option. To |
| retrieve options at the socket level, specify the level argument as |
| SOL_SOCKET.</p> |
| <p>See <code class="docutils literal notranslate"><span class="pre">sys/socket.h</span></code> for a complete list of values for the <code class="docutils literal notranslate"><span class="pre">option</span></code> |
| argument.</p> |
| <p><strong>Input Parameters:</strong></p> |
| <ul class="simple"> |
| <li><p><code class="docutils literal notranslate"><span class="pre">sockfd</span></code>: Socket descriptor of socket</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">level</span></code>: Protocol level to set the option</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">option</span></code>: Identifies the option to get</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">value</span></code>: Points to the argument value</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">value_len</span></code>: The length of the argument value</p></li> |
| </ul> |
| <p><strong>Returned Value:</strong> On success, returns the number of characters sent. |
| On error, -1 is returned, and <code class="docutils literal notranslate"><span class="pre">`errno</span></code> <#ErrnoAccess>`__ is set |
| appropriately:</p> |
| <ul class="simple"> |
| <li><p><code class="docutils literal notranslate"><span class="pre">BADF</span></code>. The <code class="docutils literal notranslate"><span class="pre">sockfd</span></code> argument is not a valid socket descriptor.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">INVAL</span></code>. The specified option is invalid at the specified socket |
| <code class="docutils literal notranslate"><span class="pre">level</span></code> or the socket has been shutdown.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">NOPROTOOPT</span></code>. The <code class="docutils literal notranslate"><span class="pre">option</span></code> is not supported by the protocol.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">NOTSOCK</span></code>. The <code class="docutils literal notranslate"><span class="pre">sockfd</span></code> argument does not refer to a socket.</p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">NOBUFS</span></code>. Insufficient resources are available in the system to |
| complete the call.</p></li> |
| </ul> |
| </dd></dl> |
| |
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