AF_NETROM - NET/ROM amateur packet radio protocol family
is a protocol used extensively by radio amateurs. The Linux
NET/ROM protocol family permits access to these protocols via the standard
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
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.
(2), setsockopt(2), getsockopt(2),
Jonathan Naylor G4KLX <email@example.com>