netctrl(2) — AIX PS/2 1.2.1



NETCTRL(2,L)                AIX Technical Reference                NETCTRL(2,L)



-------------------------------------------------------------------------------
netctrl



PURPOSE

Allows system administrator to exercise control over TCF networking.

SYNTAX

#include <sys/netctrl.h>

int netctrl(option, param)
int option;
caddr_t param;

DESCRIPTION

The netctrl system call provides the superuser with a method for controlling
the behavior of the TCF network (that is, cluster communication).  The option
parameter may be ORed with SET_OPT to cause the value(s) to be set or reset as
appropriate in addition to returning the old value(s).  The various structures
to which param may refer are defined in <sys/netctrl.h>.  The following options
are available:

NET_FLOW  Controls TCF cluster communication (network traffic) and/or returns
          current state.  param is the address of an integer whose value is
          NET_START, NETJOIN, or NET_STOP.

          NET_START     starts a cluster communication, allowing it to join a
                        cluster with other TCF sites.

          NET_JOIN      is used after cluster communication is enabled to
                        actively look for other cluster sites and hence join a
                        cluster.  NET_JOIN is usually used immediately after
                        NET_START.

          NET_STOP      stops cluster communication.

          Note:  On AIX/370, in addition to enabling cluster communication,
                 NET_START enables communication using a telecommunications
                 adapter (TCA) for use by AIX Access.  NET_STOP, however, does
                 not disable TCA traffic.

NET_STATS Get current TCF network statistics gathered since last network
          startup.  This information is returned into a net_stats structure as
          pointed to by param.  If SET_OPT is set, then the statistics are
          reset within the kernel.






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For the following options, if more sites exist than are implied by the number
of entries specified by the param argument, the values for those sites are
simply not returned or modified.

SITE_STATS
          Get current statistics on TCF sites.  This information is returned
          into a site_stats structure as pointed to by param.  If SET_OPT is
          set, then the statistics are reset within the kernel.

MSG_STATS Get current statistics on message traffic on a per site basis.  This
          information is returned into a msg_stats structure as pointed to by
          param.  If SET_OPT is set, then the statistics are reset within the
          kernel.

SITE_PARMS
          Get or set current site parameters as determined by the site_parms
          structure which is pointed to by param.  Values for the site_parms
          structure may have the following values:

          sp_route     Reserved for future implementation.

          sp_timeout   Must be greater than or equal to 2.

          sp_block_size
                       Must be a power of 2 greater than or equal to 512 and
                       less than or equal to 16384.

          sp_retries   Must be greater than 0.

          sp_window    Must be greater than 0.

          sp_s_window  Must be greater than or equal to 1.

          sp_checksum  If 1, checksumming is done.  If 0, no checksumming is
                       done.

NET_TOPWAIT
          Wait for change in TCF cluster topology.  The param parameter is a
          pointer to a character whose value is one of the topology change
          status values defined in <sys/topchg.h<:

             TP_PARTITION
             TP_CLEANUP
             TP_MERGE
             TP_NEWTOP
             TP_RECOVERY
             TP_CANCEL
             TP_WAIT
             TP_STABLE

          Usually, the first time NET_WAIT is used, the value TP_STABLE is
          passed.



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NETCTRL(2,L)                AIX Technical Reference                NETCTRL(2,L)




          The netctrl system call will wait until the current topology change
          status is different from the provided value; at which point the
          system call will return, replacing the character pointed at by param
          with the then current topology status.  Because there may be multiple
          changes in the topology status before this process gets a chance to
          run-it is possible that the returned topology change status actually
          equals the value passed in.

RETURN VALUE

Upon successful completion, a value of 0 is returned to the calling process.
Otherwise, a value of -1 is returned and errno is set to indicate the error.

ERROR CONDITIONS

The netctrl system call fails if any of the following is true:

EPERM     The SET_OPT bit was on and the user was not the superuser.

EINVAL    Option is not an one of the choices described above.

EINVAL    One or more of the parameters specified in the site_parms structure
          are outside of the acceptable ranges.

EFAULT    param pointed to an area which was unwritable.

EBUSY     NET_JOIN was specified while already in the process of joining a
          cluster.

EINVAL    TCF is not enabled on your system (AIX PS/2 only).

RELATED INFORMATION

In this book:  "getsites."

The clusterstart, clusterstop, and netparams commands in AIX Operating System
Commands Reference.

















Processed November 7, 1990       NETCTRL(2,L)                                 3

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