diff options
Diffstat (limited to 'Documentation/networking/phonet.txt')
| -rw-r--r-- | Documentation/networking/phonet.txt | 67 |
1 files changed, 25 insertions, 42 deletions
diff --git a/Documentation/networking/phonet.txt b/Documentation/networking/phonet.txt index 24ad2adba6e5..81003581f47a 100644 --- a/Documentation/networking/phonet.txt +++ b/Documentation/networking/phonet.txt @@ -154,9 +154,28 @@ connections, one per accept()'d socket. write(cfd, msg, msglen); } -Connections are established between two endpoints by a "third party" -application. This means that both endpoints are passive; so connect() -is not possible. +Connections are traditionally established between two endpoints by a +"third party" application. This means that both endpoints are passive. + + +As of Linux kernel version 2.6.39, it is also possible to connect +two endpoints directly, using connect() on the active side. This is +intended to support the newer Nokia Wireless Modem API, as found in +e.g. the Nokia Slim Modem in the ST-Ericsson U8500 platform: + + struct sockaddr_spn spn; + int fd; + + fd = socket(PF_PHONET, SOCK_SEQPACKET, PN_PROTO_PIPE); + memset(&spn, 0, sizeof(spn)); + spn.spn_family = AF_PHONET; + spn.spn_obj = ...; + spn.spn_dev = ...; + spn.spn_resource = 0xD9; + connect(fd, (struct sockaddr *)&spn, sizeof(spn)); + /* normal I/O here ... */ + close(fd); + WARNING: When polling a connected pipe socket for writability, there is an @@ -181,45 +200,9 @@ The pipe protocol provides two socket options at the SOL_PNPIPE level: interface index of the network interface created by PNPIPE_ENCAP, or zero if encapsulation is off. - -Phonet Pipe-controller Implementation -------------------------------------- - -Phonet Pipe-controller is enabled by selecting the CONFIG_PHONET_PIPECTRLR Kconfig -option. It is useful when communicating with those Nokia Modems which do not -implement Pipe controller in them e.g. Nokia Slim Modem used in ST-Ericsson -U8500 platform. - -The implementation is based on the Data Connection Establishment Sequence -depicted in 'Nokia Wireless Modem API - Wireless_modem_user_guide.pdf' -document. - -It allows a phonet sequenced socket (host-pep) to initiate a Pipe connection -between itself and a remote pipe-end point (e.g. modem). - -The implementation adds socket options at SOL_PNPIPE level: - - PNPIPE_PIPE_HANDLE - It accepts an integer argument for setting value of pipe handle. - - PNPIPE_ENABLE accepts one integer value (int). If set to zero, the pipe - is disabled. If the value is non-zero, the pipe is enabled. If the pipe - is not (yet) connected, ENOTCONN is error is returned. - -The implementation also adds socket 'connect'. On calling the 'connect', pipe -will be created between the source socket and the destination, and the pipe -state will be set to PIPE_DISABLED. - -After a pipe has been created and enabled successfully, the Pipe data can be -exchanged between the host-pep and remote-pep (modem). - -User-space would typically follow below sequence with Pipe controller:- --socket --bind --setsockopt for PNPIPE_PIPE_HANDLE --connect --setsockopt for PNPIPE_ENCAP_IP --setsockopt for PNPIPE_ENABLE + PNPIPE_HANDLE is a read-only integer value. It contains the underlying + identifier ("pipe handle") of the pipe. This is only defined for + socket descriptors that are already connected or being connected. Authors |