| home
topology files
command‑line options
the core API
FAQ
download and install
|
cnet's core data structures
cnet's provides a number of core data structures,
each defined in the <cnet.h> header file.
Each node has access to its own instance of these data structures.
The data structures are:
The nodeinfo data structure
Each node's attributes may be accessed with,
for example,
if(nodeinfo.nlinks > 1) ...
| datatype |
fieldname |
meaning |
| CnetNodeType |
nodetype |
one of NT_HOST, NT_ROUTER, NT_MOBILE, or NT_ACCESSPOINT |
| int |
nodenumber |
this node's unique number, from 0 .. number_of_nodes-1 |
| CnetAddr |
address |
this node's unique address |
| char array |
nodename |
this node's unique name, a nul-byte terminated string
such as host3 or Perth |
| int |
nlinks |
this node's number of physical links, ≥ 1 |
| CnetTime |
time_in_usec |
the number of microseconds since this node last rebooted |
| structure of 2 ints |
time_of_day |
this node's "wall clock" time,
with subfields time_of_day.secs and time_of_day.usec |
| CnetTime |
messagerate |
the rate (in microseconds) at which this node's Application Layer
generates new messages |
| int |
minmessagesize |
the minimum sized message to be generated by this node's Application Layer |
| int |
maxmessagesize |
the maximum sized message to be generated by this node's Application Layer |
The linkinfo data structure
The attributes of
each node's links may be accessed via fields in the linkinfo data
structure.
linkinfo is an array,
of type LinkInfo,
indexed by the required link number.
Link numbers commence at 0 (for the LT_LOOPBACK link);
the first "true", physical link has the index 1.
Each link's attributes may be accessed with,
for example,
if(linkinfo[1].linkup) ...
| datatype |
fieldname |
meaning |
| CnetLinkType |
linktype |
one of LT_LOOPBACK, LT_WAN, LT_LAN, or LT_WLAN |
| char array |
linkname |
this link's unique name, a nul-byte terminated string such as
lan1 or wlan0 |
| bool |
linkup |
true iff this link is up and functioning correctly |
| CnetNICaddr |
nicaddr |
this link's network interface card's (NIC's) address |
| int |
bandwidth |
this link's bandwidth, in bits per second |
| int |
mtu |
this link's maximum transmission unit (MTU) in bytes |
| CnetTime |
propagationdelay |
the propagation delay (in microseconds) along this link,
iff a LT_WAN or LT_LAN link |
| int |
costperbyte |
the (unitless) cost of transmitting each byte on this link |
| int |
costperframe |
the (unitless) cost of transmitting each frame on this link |
|
