1 files changed, 147 insertions, 0 deletions
diff --git a/api/ifcounters/ifcounters.go b/api/ifcounters/ifcounters.go
new file mode 100644
index 0000000..202fe6e
--- /dev/null
+++ b/api/ifcounters/ifcounters.go
@@ -0,0 +1,147 @@
+// Copyright (c) 2017 Cisco and/or its affiliates.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at:
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package ifcounters
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+
+	"github.com/lunixbochs/struc"
+)
+
+// VnetInterfaceCounters is the input data type defined in the 'interface.api', with binary encoded Data field,
+// that can be decoded into the InterfaceCounter or CombinedInterfaceCounter struct using this package.
+type VnetInterfaceCounters struct {
+	VnetCounterType uint8
+	IsCombined      uint8
+	FirstSwIfIndex  uint32
+	Count           uint32 `struc:"sizeof=Data"`
+	Data            []byte
+}
+
+// CounterType is the basic counter type - contains only packet statistics.
+type CounterType int
+
+// constants as defined in the vnet_interface_counter_type_t enum in 'vnet/interface.h'
+const (
+	Drop    CounterType = 0
+	Punt                = 1
+	IPv4                = 2
+	IPv6                = 3
+	RxNoBuf             = 4
+	RxMiss              = 5
+	RxError             = 6
+	TxError             = 7
+	MPLS                = 8
+)
+
+// CombinedCounterType is the extended counter type - contains both packet and byte statistics.
+type CombinedCounterType int
+
+// constants as defined in the vnet_interface_counter_type_t enum in 'vnet/interface.h'
+const (
+	Rx CombinedCounterType = 0
+	Tx                     = 1
+)
+
+// InterfaceCounter contains basic counter data (contains only packet statistics).
+type InterfaceCounter struct {
+	Type      CounterType
+	SwIfIndex uint32
+	Packets   uint64
+}
+
+// CombinedInterfaceCounter contains extended counter data (contains both packet and byte statistics).
+type CombinedInterfaceCounter struct {
+	Type      CombinedCounterType
+	SwIfIndex uint32
+	Packets   uint64
+	Bytes     uint64
+}
+
+type counterData struct {
+	Packets uint64
+}
+
+type counter struct {
+	Count uint32 `struc:"sizeof=Data"`
+	Data  []counterData
+}
+
+type combinedCounterData struct {
+	Packets uint64
+	Bytes   uint64
+}
+
+type combinedCounter struct {
+	Count uint32 `struc:"sizeof=Data"`
+	Data  []combinedCounterData
+}
+
+// DecodeCounters decodes VnetInterfaceCounters struct content into the slice of InterfaceCounter structs.
+func DecodeCounters(vnetCounters VnetInterfaceCounters) ([]InterfaceCounter, error) {
+	if vnetCounters.IsCombined == 1 {
+		return nil, errors.New("invalid argument - combined counter passed in")
+	}
+
+	// decode into internal struct
+	var c counter
+	buf := bytes.NewReader(vnetCounters.Data)
+	err := struc.Unpack(buf, &c)
+	if err != nil {
+		return nil, fmt.Errorf("unable to decode counter data: %v", err)
+	}
+
+	// prepare the slice
+	res := make([]InterfaceCounter, c.Count)
+
+	// fill in the slice
+	for i := uint32(0); i < c.Count; i++ {
+		res[i].Type = CounterType(vnetCounters.VnetCounterType)
+		res[i].SwIfIndex = vnetCounters.FirstSwIfIndex + i
+		res[i].Packets = c.Data[i].Packets
+	}
+
+	return res, nil
+}
+
+// DecodeCombinedCounters decodes VnetInterfaceCounters struct content into the slice of CombinedInterfaceCounter structs.
+func DecodeCombinedCounters(vnetCounters VnetInterfaceCounters) ([]CombinedInterfaceCounter, error) {
+	if vnetCounters.IsCombined != 1 {
+		return nil, errors.New("invalid argument - simple counter passed in")
+	}
+
+	// decode into internal struct
+	var c combinedCounter
+	buf := bytes.NewReader(vnetCounters.Data)
+	err := struc.Unpack(buf, &c)
+	if err != nil {
+		return nil, fmt.Errorf("unable to decode counter data: %v", err)
+	}
+
+	// prepare the slice
+	res := make([]CombinedInterfaceCounter, c.Count)
+
+	// fill in the slice
+	for i := uint32(0); i < c.Count; i++ {
+		res[i].Type = CombinedCounterType(vnetCounters.VnetCounterType)
+		res[i].SwIfIndex = vnetCounters.FirstSwIfIndex + i
+		res[i].Packets = c.Data[i].Packets
+		res[i].Bytes = c.Data[i].Bytes
+	}
+
+	return res, nil
+}