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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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| <tt><font size=+1>#include <libc.h> |
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| <tt><font size=+1>#include <ip.h> |
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| <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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| <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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