Difference between revisions of "UDP"

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(Created page with '== Sending data over UDP == '''Step 1: Allocate a new UDP device.''' :Use udpAlloc to get a device number for a udp device. If allocation fails, the device number returned will ...')
 
 
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== Sending data over UDP ==
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== Resources ==
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XINU implements UDP as per RFC 768
  
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'''Step 1: Allocate a new UDP device.'''
 
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:Use udpAlloc to get a device number for a udp device. If allocation fails, the device number returned will be SYSERR.
 
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dev = tcpAlloc())
 
  
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'''Step 2: Get the local ip address'''
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== Debugging ==
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:Use netLookup to find our local ip address.
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To enable UDP debugging, uncomment the following line in include/udp.h
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:If interface is NULL, then we don't have a valid network interface.  
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//#define TRACE_UDP    TTY1
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This usually happens when a user forgets to run the netup command.
 
  
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interface = netLookup((ethertab[0].dev)->num);
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In order to see the trace results you open another console to the second serial port using the router name followed by the number 2.
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localhost = &(interface->ip);
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mips-console router2
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Alternatively TTY1 can be changed to TTY0 resulting in the trace printing on the main console.
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'''Step3: Open the UDP device'''
 
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:To open the device simply call open( ) with the following arguments:
 
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#The UDP device number
 
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#Our local ip address
 
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#The destination's ip address
 
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#The local port to use
 
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#The remote port to connect to
 
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open(dev, localIP, dstIP, localPort, remotePort)
 
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Again if open fails, SYSERR is returned.
 
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'''Step 4: Send the packet'''
 
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:To actually send the data, use write( ) with the device, buffer, and length arguments.
 
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:The actual data you want to send will be written to the buffer. The length arg is the length of the buffer.
 
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  write(dev, buf, MSG_MAX_LEN)
 
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As usual, write returns SYSERR if it fails.
 
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'''Step 5: Close the connection'''
 
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:Once the device is finish being used, be responsible and call close to return the device.
 
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close(dev);
 

Latest revision as of 18:45, 17 June 2011

Resources

XINU implements UDP as per RFC 768


Debugging

To enable UDP debugging, uncomment the following line in include/udp.h 

//#define TRACE_UDP     TTY1

In order to see the trace results you open another console to the second serial port using the router name followed by the number 2. 

mips-console router2

Alternatively TTY1 can be changed to TTY0 resulting in the trace printing on the main console.

Retrieved from "https://xinu.cs.mu.edu/index.php?title=UDP&oldid=3856"