[BPF] make conntrack timeouts configurable

BPFConntrackTimers overides the default values for the specified conntrack timer if
set. It is a struct of values, where each value can be either a duration or `auto` to
pick the value from a Linux conntrack timeout.

Possible values for the keys are: CreationGracePeriod, TCPPreEstablished,
TCPEstablished, TCPFinsSeen, TCPResetSeen, UDPLastSeen, GenericIPLastSeen,
ICMPLastSeen.

Unset or incorrect values are replaced by the default values with a warning log for
incorrect values.

Current auto mappings:

TCPPreEstablished: nf_conntrack_tcp_timeout_syn_sent
TCPEstablished:    nf_conntrack_tcp_timeout_established
TCPFinsSeen:       nf_conntrack_tcp_timeout_time_wait
GenericIPLastSeen: nf_conntrack_generic_timeout
ICMPLastSeen:      nf_conntrack_icmp_timeout

If there is no mapping, 'auto' is replaced by the default value.

[Default:
     CreationGracePeriod: 10s
     TCPPreEstablished:   20s
     TCPEstablished:      1h
     TCPFinsSeen:         auto (30s is default)
     TCPResetSeen:        40s
     UDPLastSeen:         60s
     GenericIPLastSeen:   10m
     ICMPLastSeen:        5s
]

api/pkg/apis/projectcalico/v3/felixconfig.go

@@ -611,6 +611,40 @@ type FelixConfigurationSpec struct {
 	// [Default: Auto]
 	BPFConntrackCleanupMode *BPFConntrackMode `json:"bpfConntrackMode,omitempty" validate:"omitempty,oneof=Auto Userspace BPFProgram"`
 
+	// BPFConntrackTimers overides the default values for the specified conntrack timer if
+	// set. It is a key-value make, where each value can be either a duration or `auto` to
+	// pick the value from a Linux conntrack timeout.
+	//
+	// Possible values for the keys are: CreationGracePeriod, TCPPreEstablished,
+	// TCPEstablished, TCPFinsSeen, TCPResetSeen, UDPLastSeen, GenericIPLastSeen,
+	// ICMPLastSeen.
+	//
+	// Unset or incorrect values are replaced by the default values with a warning log for
+	// incorrect values.
+	//
+	// Current auto mappings:
+	//
+	// TCPPreEstablished: nf_conntrack_tcp_timeout_syn_sent
+	// TCPEstablished:    nf_conntrack_tcp_timeout_established
+	// TCPFinsSeen:       nf_conntrack_tcp_timeout_time_wait
+	// GenericIPLastSeen: nf_conntrack_generic_timeout
+	// ICMPLastSeen:      nf_conntrack_icmp_timeout
+	//
+	// If there is no mapping, 'auto' is replaced by the default value.
+	//
+	// [Default:
+	//	CreationGracePeriod: 10s
+	//	TCPPreEstablished:   20s
+	//	TCPEstablished:      1h
+	//	TCPFinsSeen:         auto (30s is default)
+	//	TCPResetSeen:        40s
+	//	UDPLastSeen:         60s
+	//	GenericIPLastSeen:   10m
+	//	ICMPLastSeen:        5s
+	// ]
+	// +optional
+	BPFConntrackTimeouts *BPFConntrackTimeouts `json:"bpfConntrackTimeouts,omitempty" validate:"omitempty"`
+
 	// BPFLogFilters is a map of key=values where the value is
 	// a pcap filter expression and the key is an interface name with 'all'
 	// denoting all interfaces, 'weps' all workload endpoints and 'heps' all host
@@ -941,6 +975,20 @@ type ProtoPort struct {
 	Net string `json:"net,omitempty"`
 }
 
+// +kubebuilder:validation:Pattern=`^(([0-9]*(\.[0-9]*)?(ms|s|h|m|us)+)+|auto)$`
+type BPFConntrackTimeout string
+
+type BPFConntrackTimeouts struct {
+	CreationGracePeriod BPFConntrackTimeout `json:"creationGracePeriod,omitempty"`
+	TCPPreEstablished   BPFConntrackTimeout `json:"tcpPreEstablished,omitempty"`
+	TCPEstablished      BPFConntrackTimeout `json:"tcpEstablished,omitempty"`
+	TCPFinsSeen         BPFConntrackTimeout `json:"tcpFinsSeen,omitempty"`
+	TCPResetSeen        BPFConntrackTimeout `json:"tcpResetSeen,omitempty"`
+	UDPLastSeen         BPFConntrackTimeout `json:"udpLastSeen,omitempty"`
+	GenericIPLastSeen   BPFConntrackTimeout `json:"genericIPLastSeen,omitempty"`
+	ICMPLastSeen        BPFConntrackTimeout `json:"icmpLastSeen,omitempty"`
+}
+
 // New FelixConfiguration creates a new (zeroed) FelixConfiguration struct with the TypeMetadata
 // initialized to the current version.
 func NewFelixConfiguration() *FelixConfiguration {

felix/bpf/conntrack/timeouts.go

@@ -15,6 +15,12 @@
 package conntrack
 
 import (
+	"bufio"
+	"fmt"
+	"os"
+	"reflect"
+	"strconv"
+	"strings"
 	"time"
 
 	log "github.com/sirupsen/logrus"
@@ -99,3 +105,89 @@ func DefaultTimeouts() Timeouts {
 		ICMPLastSeen:        5 * time.Second,
 	}
 }
+
+var linuxSysctls = map[string]string{
+	"TCPPreEstablished": "nf_conntrack_tcp_timeout_syn_sent",
+	"TCPEstablished":    "nf_conntrack_tcp_timeout_established",
+	"TCPFinsSeen":       "nf_conntrack_tcp_timeout_time_wait",
+	"GenericIPLastSeen": "nf_conntrack_generic_timeout",
+	"ICMPLastSeen":      "nf_conntrack_icmp_timeout",
+}
+
+func GetTimeouts(config map[string]string) Timeouts {
+	t := DefaultTimeouts()
+
+	v := reflect.ValueOf(&t)
+	v = v.Elem()
+
+	for key, value := range config {
+		field := v.FieldByName(key)
+		if !field.IsValid() {
+			log.WithField("value", key).Warn("Not a valid BPF conntrack timeout, skipping")
+			continue
+		}
+
+		d, err := time.ParseDuration(value)
+		if err == nil {
+			log.WithFields(log.Fields{"name": key, "value": d}).Info("BPF conntrack timeout set")
+			field.SetInt(int64(d))
+			continue
+		}
+
+		if value == "auto" {
+			sysctl := linuxSysctls[key]
+			if sysctl != "" {
+				seconds, err := readSecondsFromFile(sysctl)
+				if err == nil {
+					d := time.Duration(seconds) * time.Second
+					log.WithFields(log.Fields{"name": key, "value": d}).Infof("BPF conntrack timeout set from %s", sysctl)
+					field.SetInt(int64(d))
+					continue
+				}
+			}
+		}
+
+		log.WithField("value", key).Warnf("Not a valid BPF conntrack timeout value, using default %s",
+			time.Duration(field.Int()))
+	}
+
+	fields := make(log.Fields)
+
+	tt := reflect.TypeOf(t)
+
+	for i := 0; i < v.NumField(); i++ {
+		fields[tt.Field(i).Name] = v.Field(i).Interface()
+	}
+
+	log.WithFields(fields).Infof("BPF conntrack timers")
+
+	return t
+}
+
+func readSecondsFromFile(nfTimeout string) (int, error) {
+	filePath := "/proc/sys/net/netfilter/" + nfTimeout
+
+	file, err := os.Open(filePath)
+	if err != nil {
+		return 0, fmt.Errorf("error opening file: %w", err)
+	}
+	defer file.Close()
+
+	scanner := bufio.NewScanner(file)
+	if scanner.Scan() {
+		line := scanner.Text()
+		line = strings.TrimSpace(line)
+		seconds, err := strconv.Atoi(line)
+		if err != nil {
+			return 0, fmt.Errorf("error converting the value to an integer: %w", err)
+		}
+
+		return seconds, nil
+	}
+
+	if err := scanner.Err(); err != nil {
+		return 0, fmt.Errorf("error reading from file: %w", err)
+	}
+
+	return 0, fmt.Errorf("file is empty or cannot read a line")
+}

felix/config/config_params.go

@@ -180,6 +180,7 @@ type Config struct {
 	BPFLogLevel                        string            `config:"oneof(off,info,debug);off;non-zero"`
 	BPFConntrackLogLevel               string            `config:"oneof(off,debug);off;non-zero"`
 	BPFConntrackCleanupMode            string            `config:"oneof(Auto,Userspace,BPFProgram);Auto"`
+	BPFConntrackTimeouts               map[string]string `config:"keyvaluelist;CreationGracePeriod=10s,TCPPreEstablished=20s,TCPEstablished=1h,TCPFinsSeen=auto,TCPResetSeen=40s,UDPLastSeen=60s,GenericIPLastSeen=10m,ICMPLastSeen=5s"`
 	BPFLogFilters                      map[string]string `config:"keyvaluelist;;"`
 	BPFCTLBLogFilter                   string            `config:"oneof(all);;"`
 	BPFDataIfacePattern                *regexp.Regexp    `config:"regexp;^((en|wl|ww|sl|ib)[Popsx].*|(eth|wlan|wwan|bond).*)"`

felix/dataplane/driver.go

@@ -378,7 +378,7 @@ func StartDataplaneDriver(
 			BPFDisableGROForIfaces:             configParams.BPFDisableGROForIfaces,
 			XDPEnabled:                         configParams.XDPEnabled,
 			XDPAllowGeneric:                    configParams.GenericXDPEnabled,
-			BPFConntrackTimeouts:               conntrack.DefaultTimeouts(), // FIXME make timeouts configurable
+			BPFConntrackTimeouts:               conntrack.GetTimeouts(configParams.BPFConntrackTimeouts),
 			BPFConntrackCleanupMode:            apiv3.BPFConntrackMode(configParams.BPFConntrackCleanupMode),
 			RouteTableManager:                  routeTableIndexAllocator,
 			MTUIfacePattern:                    configParams.MTUIfacePattern,