56 lines
		
	
	
		
			2.0 KiB
		
	
	
	
		
			TeX
		
	
	
	
	
	
			
		
		
	
	
			56 lines
		
	
	
		
			2.0 KiB
		
	
	
	
		
			TeX
		
	
	
	
	
	
\subsubsection{Using the network scripts}
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To be able to access the network functions, you need to include
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the necessary shell scripts by running:
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\begin{Verbatim}
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. /lib/functions.sh      # common functions
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include /lib/network     # include /lib/network/*.sh
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scan_interfaces          # read and parse the network config
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\end{Verbatim}
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Some protocols, such as PPP might change the configured interface names
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at run time (e.g. \texttt{eth0} => \texttt{ppp0} for PPPoE). That's why you have to run
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\texttt{scan\_interfaces} instead of reading the values from the config directly.
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After running \texttt{scan\_interfaces}, the \texttt{'ifname'} option will always contain
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the effective interface name (which is used for IP traffic) and if the
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physical device name differs from it, it will be stored in the \texttt{'device'}
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option.
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That means that running \texttt{config\_get lan ifname}
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after \texttt{scan\_interfaces} might not return the same result as running it before.
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After running \texttt{scan\_interfaces}, the following functions are available:
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\begin{itemize}
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    \item{\texttt{find\_config \textit{interface}}} \\
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        looks for a network configuration that includes
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        the specified network interface.
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    \item{\texttt{setup\_interface \textit{interface [config] [protocol]}}} \\
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      will set up the specified interface, optionally overriding the network configuration
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      name or the protocol that it uses.
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\end{itemize}
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\subsubsection{Writing protocol handlers}
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You can add custom protocol handlers (e.g: PPPoE, PPPoA, ATM, PPTP ...)
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by adding shell scripts to \texttt{/lib/network}. They provide the following
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two shell functions:
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\begin{Verbatim}
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scan_<protocolname>() {
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    local config="$1"
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    # change the interface names if necessary
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}
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setup_interface_<protocolname>() {
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    local interface="$1"
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    local config="$2"
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    # set up the interface
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}
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\end{Verbatim}
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\texttt{scan\_\textit{protocolname}} is optional and only necessary if your protocol
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uses a custom device, e.g. a tunnel or a PPP device.
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