Root/docs/network-scripts.tex

1\subsubsection{Using the network scripts}
2
3To be able to access the network functions, you need to include
4the necessary shell scripts by running:
5
6\begin{Verbatim}
7. /lib/functions.sh # common functions
8include /lib/network # include /lib/network/*.sh
9scan_interfaces # read and parse the network config
10\end{Verbatim}
11
12Some protocols, such as PPP might change the configured interface names
13at run time (e.g. \texttt{eth0} => \texttt{ppp0} for PPPoE). That's why you have to run
14\texttt{scan\_interfaces} instead of reading the values from the config directly.
15After running \texttt{scan\_interfaces}, the \texttt{'ifname'} option will always contain
16the effective interface name (which is used for IP traffic) and if the
17physical device name differs from it, it will be stored in the \texttt{'device'}
18option.
19That means that running \texttt{config\_get lan ifname}
20after \texttt{scan\_interfaces} might not return the same result as running it before.
21
22After running \texttt{scan\_interfaces}, the following functions are available:
23
24\begin{itemize}
25    \item{\texttt{find\_config \textit{interface}}} \\
26        looks for a network configuration that includes
27        the specified network interface.
28
29    \item{\texttt{setup\_interface \textit{interface [config] [protocol]}}} \\
30      will set up the specified interface, optionally overriding the network configuration
31      name or the protocol that it uses.
32\end{itemize}
33
34\subsubsection{Writing protocol handlers}
35
36You can add custom protocol handlers (e.g: PPPoE, PPPoA, ATM, PPTP ...)
37by adding shell scripts to \texttt{/lib/network}. They provide the following
38two shell functions:
39
40\begin{Verbatim}
41scan_<protocolname>() {
42    local config="$1"
43    # change the interface names if necessary
44}
45
46setup_interface_<protocolname>() {
47    local interface="$1"
48    local config="$2"
49    # set up the interface
50}
51\end{Verbatim}
52
53\texttt{scan\_\textit{protocolname}} is optional and only necessary if your protocol
54uses a custom device, e.g. a tunnel or a PPP device.
55
56

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