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add oversize msg metric #122

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merged 3 commits into from
Jun 30, 2020
Merged

add oversize msg metric #122

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70686e3
add oversize msg metric
Jun 30, 2020
ebee1bd
add metric for ignored messages
Jun 30, 2020
279a15f
fix docstring
Jun 30, 2020
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16 changes: 16 additions & 0 deletions metrics/metrics.go
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Original file line number Diff line number Diff line change
Expand Up @@ -152,6 +152,22 @@ var (
Help: "Number of snapshots taken.",
},
)

// LargeNetlinkMsgTotal counts the total number of snapshots collected across all connections.
LargeNetlinkMsgTotal = promauto.NewCounterVec(
prometheus.CounterOpts{
Name: "large_netlink_total",
Help: "Number of oversize netlink messages.",
}, []string{"type"},
)

// NetlinkNotDecoded counts the total number of snapshots collected across all connections.
NetlinkNotDecoded = promauto.NewCounterVec(
prometheus.CounterOpts{
Name: "netlink_skipped_total",
Help: "Number of skipped netlink messages.",
}, []string{"type"},
)
)

// init() prints a log message to let the user know that the package has been
Expand Down
39 changes: 25 additions & 14 deletions snapshot/snapshot.go
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Original file line number Diff line number Diff line change
Expand Up @@ -4,20 +4,24 @@ package snapshot

import (
"errors"
"fmt"
"io"
"log"
"time"
"unsafe"

"github.com/m-lab/go/logx"
"github.com/m-lab/tcp-info/inetdiag"
"github.com/m-lab/tcp-info/metrics"
"github.com/m-lab/tcp-info/netlink"
"github.com/m-lab/tcp-info/tcp"
)

// ErrEmptyRecord is returned if an ArchivalRecord is empty.
var ErrEmptyRecord = errors.New("Message should contain Metadata or RawIDM")

var missingDecodeLog = logx.NewLogEvery(nil, time.Second)

// Decode decodes a netlink.ArchivalRecord into a single Snapshot
// Initial ArchivalRecord may have just a Snapshot, just Metadata, or both.
func Decode(ar *netlink.ArchivalRecord) (*netlink.Metadata, *Snapshot, error) {
Expand Down Expand Up @@ -62,24 +66,28 @@ func Decode(ar *netlink.ArchivalRecord) (*netlink.Metadata, *Snapshot, error) {
case inetdiag.INET_DIAG_PROTOCOL:
result.Protocol, ok = rta.toProtocol()
case inetdiag.INET_DIAG_SKV6ONLY:
log.Println("SKV6ONLY not handled", len(rta))
metrics.NetlinkNotDecoded.WithLabelValues("INET_DIAG_SKV6ONLY").Inc()
missingDecodeLog.Println("SKV6ONLY not handled", len(rta))
case inetdiag.INET_DIAG_LOCALS:
log.Println("LOCAL not handled", len(rta))
metrics.NetlinkNotDecoded.WithLabelValues("INET_DIAG_LOCALS").Inc()
missingDecodeLog.Println("LOCAL not handled", len(rta))
case inetdiag.INET_DIAG_PEERS:
log.Println("PEERS not handled", len(rta))
metrics.NetlinkNotDecoded.WithLabelValues("INET_DIAG_PEERS").Inc()
missingDecodeLog.Println("PEERS not handled", len(rta))
case inetdiag.INET_DIAG_PAD:
log.Println("PAD not handled", len(rta))
metrics.NetlinkNotDecoded.WithLabelValues("INET_DIAG_PAD").Inc()
missingDecodeLog.Println("PAD not handled", len(rta))
case inetdiag.INET_DIAG_MARK:
result.Mark, ok = rta.toMark()
case inetdiag.INET_DIAG_BBRINFO:
result.BBRInfo, ok = rta.toBBRInfo()
case inetdiag.INET_DIAG_CLASS_ID:
result.ClassID, ok = rta.toClassID()
case inetdiag.INET_DIAG_MD5SIG:
log.Println("MD5SIGnot handled", len(rta))
missingDecodeLog.Println("MD5SIGnot handled", len(rta))
default:
// TODO metric so we can alert.
log.Println("unhandled attribute type:", t)
metrics.NetlinkNotDecoded.WithLabelValues(fmt.Sprint(t)).Inc()
missingDecodeLog.Println("unhandled attribute type:", t)
}
bit := uint32(1) << uint8(t-1)
result.Observed |= bit
Expand All @@ -102,20 +110,23 @@ type RouteAttrValue []byte
// maybeCopy checks whether the src is the full size of the intended struct size.
// If so, it just returns the pointer, otherwise it copies the content to an
// appropriately sized new byte slice, and returns pointer to that.
func maybeCopy(src []byte, size int) (unsafe.Pointer, bool) {
func maybeCopy(src []byte, size int, msgType string) (unsafe.Pointer, bool) {
if len(src) < size {
data := make([]byte, size)
copy(data, src)
return unsafe.Pointer(&data[0]), true
}
// TODO Check for larger than expected, and increment a metric with appropriate label.
if len(src) > size {
metrics.LargeNetlinkMsgTotal.WithLabelValues(msgType).Inc()
}
return unsafe.Pointer(&src[0]), len(src) == size
}

// toMemInfo maps the raw RouteAttrValue onto a MemInfo.
func (raw RouteAttrValue) toMemInfo() (*inetdiag.MemInfo, bool) {
structSize := (int)(unsafe.Sizeof(inetdiag.MemInfo{}))
data, ok := maybeCopy(raw, structSize)
data, ok := maybeCopy(raw, structSize, "MemInfo")
if !ok {
oneSecondLog.Println("memInfo data is larger than struct")
}
Expand All @@ -126,7 +137,7 @@ func (raw RouteAttrValue) toMemInfo() (*inetdiag.MemInfo, bool) {
// For older data, it may have to copy the bytes.
func (raw RouteAttrValue) toLinuxTCPInfo() (*tcp.LinuxTCPInfo, bool) {
structSize := (int)(unsafe.Sizeof(tcp.LinuxTCPInfo{}))
data, ok := maybeCopy(raw, structSize)
data, ok := maybeCopy(raw, structSize, "TCPInfo")
if !ok {
oneSecondLog.Println("tcpinfo data is larger than struct")
}
Expand All @@ -137,7 +148,7 @@ func (raw RouteAttrValue) toLinuxTCPInfo() (*tcp.LinuxTCPInfo, bool) {
// For older data, it may have to copy the bytes.
func (raw RouteAttrValue) toVegasInfo() (*inetdiag.VegasInfo, bool) {
structSize := (int)(unsafe.Sizeof(inetdiag.VegasInfo{}))
data, ok := maybeCopy(raw, structSize)
data, ok := maybeCopy(raw, structSize, "VegasInfo")
return (*inetdiag.VegasInfo)(data), ok
}

Expand Down Expand Up @@ -174,7 +185,7 @@ func (raw RouteAttrValue) toClassID() (uint8, bool) {
// For older data, it may have to copy the bytes.
func (raw RouteAttrValue) toSockMemInfo() (*inetdiag.SocketMemInfo, bool) {
structSize := (int)(unsafe.Sizeof(inetdiag.SocketMemInfo{}))
data, ok := maybeCopy(raw, structSize)
data, ok := maybeCopy(raw, structSize, "SockMemInfo")
return (*inetdiag.SocketMemInfo)(data), ok
}

Expand All @@ -186,7 +197,7 @@ func (raw RouteAttrValue) toShutdown() (uint8, bool) {
// For older data, it may have to copy the bytes.
func (raw RouteAttrValue) toDCTCPInfo() (*inetdiag.DCTCPInfo, bool) {
structSize := (int)(unsafe.Sizeof(inetdiag.DCTCPInfo{}))
data, ok := maybeCopy(raw, structSize)
data, ok := maybeCopy(raw, structSize, "DCTCPInfo")
return (*inetdiag.DCTCPInfo)(data), ok
}

Expand All @@ -206,7 +217,7 @@ func (raw RouteAttrValue) toMark() (uint32, bool) {
// For older data, it may have to copy the bytes.
func (raw RouteAttrValue) toBBRInfo() (*inetdiag.BBRInfo, bool) {
structSize := (int)(unsafe.Sizeof(inetdiag.BBRInfo{}))
data, ok := maybeCopy(raw, structSize)
data, ok := maybeCopy(raw, structSize, "BBRInfo")
return (*inetdiag.BBRInfo)(data), ok
}

Expand Down