allow to configure GC percentage

Added config option to set how often the garbage collector runs.

For example:

  "Internal": {
      "GCPercent": 75
  },

If this option is not specified in the config file, or the value
is 0, then the GC percentage is not configured.

More info:

https://pkg.go.dev/runtime/debug#SetGCPercent

daemon/ui/config/config.go

@@ -59,25 +59,31 @@ type (
 	ebpfOptions struct {
 		ModulesPath string `json:"ModulesPath"`
 	}
+
+	internalOptions struct {
+		GCPercent int `json:"GCPercent"`
+	}
 )
 
 // Config holds the values loaded from configFile
 type Config struct {
 	LogLevel          *int32                 `json:"LogLevel"`
-	FwOptions         fwOptions              `json:"FwOptions"`
 	Firewall          string                 `json:"Firewall"`
-	Ebpf              ebpfOptions            `json:"Ebpf"`
 	DefaultAction     string                 `json:"DefaultAction"`
 	DefaultDuration   string                 `json:"DefaultDuration"`
 	ProcMonitorMethod string                 `json:"ProcMonitorMethod"`
+	FwOptions         fwOptions              `json:"FwOptions"`
+	Ebpf              ebpfOptions            `json:"Ebpf"`
 	Server            serverConfig           `json:"Server"`
 	Rules             rulesOptions           `json:"Rules"`
 	Stats             statistics.StatsConfig `json:"Stats"`
-	sync.RWMutex
+	Internal          internalOptions        `json:"Internal"`
 
 	InterceptUnknown bool `json:"InterceptUnknown"`
 	LogUTC           bool `json:"LogUTC"`
 	LogMicro         bool `json:"LogMicro"`
+
+	sync.RWMutex
 }
 
 // Parse determines if the given configuration is ok.

daemon/ui/config_utils.go

@@ -4,6 +4,8 @@ import (
 	"fmt"
 	"strings"
 
+	"runtime/debug"
+
 	"github.com/evilsocket/opensnitch/daemon/firewall"
 	"github.com/evilsocket/opensnitch/daemon/log"
 	"github.com/evilsocket/opensnitch/daemon/procmon/monitor"
@@ -123,6 +125,11 @@ func (c *Client) loadConfiguration(rawConfig []byte) bool {
 		}
 	}
 
+	if clientConfig.Internal.GCPercent > 0 {
+		oldgcpercent := debug.SetGCPercent(clientConfig.Internal.GCPercent)
+		log.Info("GC percent set to %d, previously was %d", clientConfig.Internal.GCPercent, oldgcpercent)
+	}
+
 	c.rules.EnableChecksums(clientConfig.Rules.EnableChecksums)
 	// TODO:
 	//c.stats.SetLimits(clientConfig.Stats)