<?xml version="1.0" encoding="ANSI_X3.4-1968" standalone="no"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968" /><title>pskb_expand_head</title><meta name="generator" content="DocBook XSL Stylesheets V1.78.1" /><link rel="home" href="index.html" title="Linux Networking and Network Devices APIs" /><link rel="up" href="ch01s02.html" title="Socket Buffer Functions" /><link rel="prev" href="API---pskb-copy.html" title="__pskb_copy" /><link rel="next" href="API-skb-copy-expand.html" title="skb_copy_expand" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center"><span class="phrase">pskb_expand_head</span></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="API---pskb-copy.html">Prev</a> </td><th width="60%" align="center">Socket Buffer Functions</th><td width="20%" align="right"> <a accesskey="n" href="API-skb-copy-expand.html">Next</a></td></tr></table><hr /></div><div class="refentry"><a id="API-pskb-expand-head"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>pskb_expand_head — reallocate header of <span class="structname">sk_buff</span> </p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><div class="funcsynopsis"><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <strong class="fsfunc">pskb_expand_head </strong>(</code></td><td>struct sk_buff * <var class="pdparam">skb</var>, </td></tr><tr><td> </td><td>int <var class="pdparam">nhead</var>, </td></tr><tr><td> </td><td>int <var class="pdparam">ntail</var>, </td></tr><tr><td> </td><td>gfp_t <var class="pdparam">gfp_mask</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1"><a id="idm140045379805168"></a><h2>Arguments</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term"><em class="parameter"><code>skb</code></em></span></dt><dd><p> buffer to reallocate </p></dd><dt><span class="term"><em class="parameter"><code>nhead</code></em></span></dt><dd><p> room to add at head </p></dd><dt><span class="term"><em class="parameter"><code>ntail</code></em></span></dt><dd><p> room to add at tail </p></dd><dt><span class="term"><em class="parameter"><code>gfp_mask</code></em></span></dt><dd><p> allocation priority </p></dd></dl></div></div><div class="refsect1"><a id="idm140045379796400"></a><h2>Description</h2><p> Expands (or creates identical copy, if <span class="structname">nhead</span> and <span class="structname">ntail</span> are zero) header of skb. <span class="structname">sk_buff</span> itself is not changed. <span class="structname">sk_buff</span> MUST have reference count of 1. Returns zero in the case of success or error, if expansion failed. In the last case, <span class="structname">sk_buff</span> is not changed. </p><p> All the pointers pointing into skb header may change and must be reloaded after call to this function. </p></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="API---pskb-copy.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="ch01s02.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="API-skb-copy-expand.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top"><span class="phrase">__pskb_copy</span> </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> <span class="phrase">skb_copy_expand</span></td></tr></table></div></body></html>