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<title>udpread(3) - Plan 9 from User Space</title>
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<tr><td width=20><td><b>UDPREAD(3)</b><td align=right><b>UDPREAD(3)</b>
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<p><font size=+1><b>NAME </b></font><br>
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udpread, udpwrite – read and write UDP packets<br>
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<p><font size=+1><b>SYNOPSIS </b></font><br>
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<tt><font size=+1>#include <u.h>
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</font></tt>
<tt><font size=+1>#include <libc.h>
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</font></tt>
<tt><font size=+1>#include <ip.h>
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</font></tt>
<tt><font size=+1>typedef struct Udphdr Udphdr;<br>
</font></tt>struct Udphdr<br>
{<br>
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uchar raddr[IPaddrlen];/* remote address and port */<br>
uchar laddr[IPaddrlen];/* local address and port */<br>
uchar rport[2];<br>
uchar lport[2];<br>
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};<br>
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<tt><font size=+1>long udpread(int fd, Udphdr *hdr, void *data, long n)<br>
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</font></tt>
<tt><font size=+1>long udpwrite(int fd, Udphdr *hdr, void *data, long n)<br>
</font></tt>
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<p><font size=+1><b>DESCRIPTION </b></font><br>
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<i>Udpread</i> and <i>udpwrite</i> read and write UDP packets from the UDP network
connection established on file descriptor <i>fd</i>.
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<i>Udpread</i> reads at most <i>n</i> bytes of packet body into <i>data ,</i> stores
the header in <i>hdr</i>, and returns the number of bytes stored in <i>data</i>.
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<i>Udpwrite</i> writes the <i>n</i> bytes stored in <i>data</i> in a UDP packet with
header <i>hdr</i>.
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Note that the <tt><font size=+1>Udphdr</font></tt> frames the addresses as local and remote
instead of source and destination. Thus the <i>hdr</i> filled in for
a packet read by <i>udpread</i> can be used unchanged in <i>udpwrite</i> to
send a response back to the sender of the original packet.<br>
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<p><font size=+1><b>SOURCE </b></font><br>
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<tt><font size=+1>/usr/local/plan9/src/lib9/udp.c<br>
</font></tt>
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<p><font size=+1><b>SEE ALSO </b></font><br>
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<a href="../man3/ip.html"><i>ip</i>(3)</a><br>
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