zeek/scripts/base/frameworks/openflow/plugins/log.zeek
Benjamin Bannier d5fd29edcd Prefer explicit construction to coercion in record initialization
While we support initializing records via coercion from an expression
list, e.g.,

    local x: X = [$x1=1, $x2=2];

this can sometimes obscure the code to readers, e.g., when assigning to
value declared and typed elsewhere. The language runtime has a similar
overhead since instead of just constructing a known type it needs to
check at runtime that the coercion from the expression list is valid;
this can be slower than just writing the readible code in the first
place, see #4559.

With this patch we use explicit construction, e.g.,

    local x = X($x1=1, $x2=2);
2025-07-11 16:28:37 -07:00

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##! OpenFlow plugin that outputs flow-modification commands
##! to a Zeek log file.
@load base/frameworks/openflow
@load base/frameworks/logging
module OpenFlow;
export {
redef enum Plugin += {
OFLOG,
};
redef enum Log::ID += { LOG };
global log_policy: Log::PolicyHook;
## Log controller constructor.
##
## dpid: OpenFlow switch datapath id.
##
## success_event: If true, flow_mod_success is raised for each logged line.
##
## Returns: OpenFlow::Controller record.
global log_new: function(dpid: count, success_event: bool &default=T): OpenFlow::Controller;
redef record ControllerState += {
## OpenFlow switch datapath id.
log_dpid: count &optional;
## Raise or do not raise success event.
log_success_event: bool &optional;
};
## The record type which contains column fields of the OpenFlow log.
type Info: record {
## Network time.
ts: time &log;
## OpenFlow switch datapath id.
dpid: count &log;
## OpenFlow match fields.
match: ofp_match &log;
## OpenFlow modify flow entry message.
flow_mod: ofp_flow_mod &log;
};
## Event that can be handled to access the :zeek:type:`OpenFlow::Info`
## record as it is sent on to the logging framework.
global log_openflow: event(rec: Info);
}
event zeek_init() &priority=5
{
Log::create_stream(OpenFlow::LOG, Log::Stream($columns=Info, $ev=log_openflow, $path="openflow", $policy=log_policy));
}
function log_flow_mod(state: ControllerState, match: ofp_match, flow_mod: OpenFlow::ofp_flow_mod): bool
{
Log::write(LOG, Info($ts=network_time(), $dpid=state$log_dpid, $match=match, $flow_mod=flow_mod));
if ( state$log_success_event )
event OpenFlow::flow_mod_success(state$_name, match, flow_mod);
return T;
}
function log_describe(state: ControllerState): string
{
return fmt("Log-%d", state$log_dpid);
}
function log_new(dpid: count, success_event: bool &default=T): OpenFlow::Controller
{
local c = OpenFlow::Controller($state=OpenFlow::ControllerState($log_dpid=dpid, $log_success_event=success_event),
$flow_mod=log_flow_mod, $describe=log_describe, $supports_flow_removed=F);
register_controller(OpenFlow::OFLOG, cat(dpid), c);
return c;
}