GETRENT (2)
getrent, getrentc, getroute, getroute2, getrtype
- Get LAM route information.
C SYNOPSIS
#include <net.h>
#include <rreq.h>
#include <events.h>
int getrent (struct route *rent);
int getrentc (struct route *rent);
int getroute (struct nmsg *nhead);
int getroute2 (struct nmsg *nhead);
int getrtype (int nodeid);
FORTRAN SYNOPSIS
integer function IGRTP (nodeid)
integer nodeid
DESCRIPTION
These functions return information obtained from the local route daemon,
a modular component of the LAM daemon.
getrent()
and
getrentc()
accept a pointer to a route structure, defined in <rreq.h>:
.5i 1i 1.5i
struct route {
int r_nodeid;
int r_event;
int r_link;
int r_event2;
int r_link2;
int r_nodetype;
};
The structure fields hold the following information.
r_nodeid
r_event
forwarding event, representing the best suggested route to the
destination node
r_link
forwarding link associated with r_event, if r_event is a datalink
output process
r_event2
secondary forwarding event, representing a non-reconvergent route
(primarily used for multicasting) with respect to other destinations
r_link2
forwarding link associated with r_event2, if r_event2 is a datalink
output process
r_nodetype
node type of destination node (see getntype(2))
getrent()
sends a request for route information to the route daemon.
The
r_nodeid
field must be set by the caller to the nodeid of the
destination node whose route table entry is required.
All other fields are filled by the function.
getrentc()
has the exact functionality of
getrent() ,
except that it caches the recently accessed route table entries.
Later access to the same entries are faster.
getrentc()
first checks the cache for the route entry of the given nodeid.
If the entry is found, the requested information is returned.
Otherwise,
getrent()
is called, returning a copy of the route table entry from the route daemon.
This entry is then stored in the cache.
The remaining functions are wrappers for
getrentc() .
getroute()
accepts a network message descriptor with the destination node and
event fields set and fills in the forwarding fields.
getroute2()
is similar to
getroute()
except that the secondary routing information is used.
getrtype()
accepts a node identifier and returns the type of that node.
C RETURN VALUE
Upon successful completion of
getrent() ,
getrentc() ,
getroute() ,
or
getroute2() ,
0 is returned.
Otherwise, -1 is returned and global error variable
errno
is set accordingly.
getrtype()
returns a valid node type when successful.
NOTNODETYPE (defined in <net.h>) is returned if an error occurs.
When an error occurs, these functions set the global variable
errno
to the appropriate error code.
FORTRAN RETURN VALUE
IGRTP()
returns a valid node type when successful.
NOTNODETYPE (see CONSTANTS(5)) is returned if an error occurs.
ERRORS
EBADNODE
The supplied node identifier does not exist.
SEE ALSO
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