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Diffstat (limited to 'static/v10/man4/tcp.4')
| -rw-r--r-- | static/v10/man4/tcp.4 | 193 |
1 files changed, 193 insertions, 0 deletions
diff --git a/static/v10/man4/tcp.4 b/static/v10/man4/tcp.4 new file mode 100644 index 00000000..8831e5cd --- /dev/null +++ b/static/v10/man4/tcp.4 @@ -0,0 +1,193 @@ +.TH TCP 4 +.CT comm_mach +.SH NAME +tcp, tcp_ld \- DARPA transmission control protocol +.SH SYNOPSIS +.B #include <sys/inio.h> +.br +.B #include <sys/inet/tcp_user.h> +.SH DESCRIPTION +The +.I tcp_ld +line discipline +and the +.F /dev/tcp* +devices together implement the DARPA TCP circuit protocol. +They are normally used through +.IR tcpmgr (8) +and the routines in +.IR ipc (3). +.PP +One instance of +.I tcp_ld +should be pushed on an IP device stream, +usually +.FR /dev/ip6 ; +see +.IR ip (4). +Thereafter, +data written on the +.I tcp +devices is turned into IP packets +written to the IP device, +and vice versa. +.PP +Different +.I tcp +devices represent different software channels. +Files with odd minor device numbers +are for placing calls; +while such a file is open, +it may not be opened again. +Files with even device numbers +receive calls. +.PP +To place a call, +open an unused odd-numbered +.I tcp +file; +write a +.B struct tcpuser +describing the address to be called; +and read a +.B struct tcpuser +for status. +The structure is defined in +.BR <sys/inet/tcp_user.h> : +.PP +.EX +struct tcpuser { + int code; + tcp_port lport, fport; + in_addr laddr, faddr; + int param; +}; + +#define TCPC_LISTEN 1 +#define TCPC_CONNECT 2 + +#define TCPC_OK 3 +#define TCPC_SORRY 4 /* unknown error */ +#define TCPC_BADDEV 5 /* tcp device is bad */ +#define TCPC_NOROUTE 6 /* no routing to dest */ +#define TCPC_BADLOCAL 7 /* bad local address */ +#define TCPC_BOUND 8 /* address already bound */ + +#define SO_KEEPALIVE 0x2 /* generate keepalives */ +.EE +.PP +In the structure describing the call, +.B code +should be +.BR TCPC_CONNECT ; +.B faddr +and +.B fport +are the destination IP address and TCP port number; +.B laddr +is the IP address associated with a local IP interface, +or +.B INADDR_ANY +to let the system pick; +.B lport +is the local TCP port number, +or +0 +to let the system pick; +.B param +is 0 or +.BR SO_KEEPALIVE . +.PP +In the structure returned for status, +.B code +is +.B TCPC_OK +if the call completed correctly; +henceforth data written to and read from the file +is transported on the circuit. +Other codes mean the circuit was not set up. +.PP +To listen for incoming calls, +open an odd-numbered device +and write a +.B struct tcpuser +with +.B code +set to +.BR TCPC_LISTEN ; +.B laddr +set to the local IP address for which calls should be taken, +or +.B INADDR_ANY +to catch any calls not explicitly taken by another listener; +.B lport +set to the port on which to listen, +or 0 for any port; +and +.B param +set to 0. +Thereafter, +reads return successive +.B tcpuser +structures, +each describing a new call; +.B faddr +and +.B fport +identify the caller, +.B laddr +and +.B lport +the assigned local address. +The local +.I tcp +device number, +.I n, +assigned to the call +is returned in +.BR param . +The corresponding device, +.BI /dev/tcp n, +should be opened; +data read and written there is transported by the circuit. +.PP +Several +.IR ioctl (2) +calls, defined in +.BR <sys/inio.h> , +apply to +.I tcp +devices: +.nr Pw \w'\f5TCPIOMAXSEG 'u +.TP \n(Pwu +.B TCPIOHUP +When the remote end of the circuit is disconnected, +send signal +.B SIGHUP +to the local process group associated with the stream. +.TP +.B TCPMAXSEG +The third argument points to an integer +giving the maximum segment size for this connection: +the greatest number of bytes to be packed into one IP packet. +.TP +.B TCPGETADDR +The third argument points to a +.BR "struct tcpuser" ; +fill in +.BR laddr , +.BR lport , +.BR faddr , +and +.BR fport +with the local and foreign addresses associated with the circuit. +.SH FILES +.F /dev/tcp?? +.br +.F /dev/ip6 +.SH SEE ALSO +.IR ip (4), +.IR internet (3), +.IR tcpmgr (8) +.br +DARPA standards RFC 793, 1122 |