AF_NETROM - NET/ROM amateur packet radio protocol family
NET/ROM is a protocol used extensively by radio amateurs. The Linux
NET/ROM protocol family permits access to these protocols via the
standard networking socket metaphor.
The NET/ROM protocol layer only supports connected mode. IP traffic may
be stacked on top of NET/ROM frames using a non-standard extension to
the NET/ROM protocol.
The only mode of operation is connected mode which is the mode used for
a socket of type SOCK_SEQPACKET (stream sockets are not available in
NET/ROM). This requires that the user ensures output data is suitably
packetised, and that input data is read a packet at a time into a
buffer of suitable size.
NET/ROM addresses consist of 6 ascii characters and a number called the
SSID. These are encoded into a sockaddr_ax25 structure which is
provided to the relevant system calls.
NET/ROM has some unusual properties. Notably in a multi-user system an
AX.25 address is often associated with a user, and some users may not
have such an association. a set of ioctl calls are provided to manage
an association table.
NET/ROM supports the following socket options for SOL_NETROM. NETROM_T1
is the T1 timer in 1/10ths of a second, NETROM_T2 is the T2 timer in
1/10ths of a second. NETROM_N2, the retry counter is also configurable.
There is no ’infinite retry’ option supported however. It is possible
for an application to request that the NET/ROM layer return the NET/ROM
header as well as the application data, this is done via the
NETROM_HDRINCL socket option.
call(1), socket(2), setsockopt(2), getsockopt(2), nrbroadcast(5),
nrports(5), netromd(8), noderest(8), nodesave(8), nrctl(8), nrparms(8).
Jonathan Naylor G4KLX <email@example.com>