1 files changed, 246 insertions, 0 deletions
diff --git a/adapter/statsclient/stat_segment.go b/adapter/statsclient/stat_segment.go
new file mode 100644
index 0000000..83afa10
--- /dev/null
+++ b/adapter/statsclient/stat_segment.go
@@ -0,0 +1,246 @@
+//  Copyright (c) 2019 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 statsclient
+
+import (
+	"fmt"
+	"net"
+	"sync/atomic"
+	"syscall"
+	"time"
+	"unsafe"
+
+	"github.com/ftrvxmtrx/fd"
+
+	"git.fd.io/govpp.git/adapter"
+)
+
+var (
+	maxWaitInProgress = time.Second * 1
+)
+
+type statSegDirectoryEntry struct {
+	directoryType statDirectoryType
+	// unionData can represent: offset, index or value
+	unionData    uint64
+	offsetVector uint64
+	name         [128]byte
+}
+
+type statDirectoryType int32
+
+func (t statDirectoryType) String() string {
+	return adapter.StatType(t).String()
+}
+
+type statSegment struct {
+	sharedHeader []byte
+	memorySize   int64
+
+	oldHeader bool
+}
+
+func (c *statSegment) connect(sockName string) error {
+	addr := &net.UnixAddr{
+		Net:  "unixpacket",
+		Name: sockName,
+	}
+
+	Log.Debugf("connecting to: %v", addr)
+
+	conn, err := net.DialUnix(addr.Net, nil, addr)
+	if err != nil {
+		Log.Warnf("connecting to socket %s failed: %s", addr, err)
+		return err
+	}
+	defer func() {
+		if err := conn.Close(); err != nil {
+			Log.Warnf("closing socket failed: %v", err)
+		}
+	}()
+
+	Log.Debugf("connected to socket")
+
+	files, err := fd.Get(conn, 1, nil)
+	if err != nil {
+		return fmt.Errorf("getting file descriptor over socket failed: %v", err)
+	}
+	if len(files) == 0 {
+		return fmt.Errorf("no files received over socket")
+	}
+	defer func() {
+		for _, f := range files {
+			if err := f.Close(); err != nil {
+				Log.Warnf("closing file %s failed: %v", f.Name(), err)
+			}
+		}
+	}()
+
+	Log.Debugf("received %d files over socket", len(files))
+
+	f := files[0]
+
+	info, err := f.Stat()
+	if err != nil {
+		return err
+	}
+
+	size := info.Size()
+
+	Log.Debugf("fd: name=%v size=%v", info.Name(), size)
+
+	data, err := syscall.Mmap(int(f.Fd()), 0, int(size), syscall.PROT_READ, syscall.MAP_SHARED)
+	if err != nil {
+		Log.Warnf("mapping shared memory failed: %v", err)
+		return fmt.Errorf("mapping shared memory failed: %v", err)
+	}
+
+	Log.Debugf("successfuly mapped shared memory")
+
+	c.sharedHeader = data
+	c.memorySize = size
+
+	header := c.readHeader()
+	Log.Debugf("stat segment header: %+v", header)
+
+	// older VPP (19.04) did not have version in stat segment header
+	// we try to provide fallback support by skipping it in header
+	if header.version > MaxVersion && header.inProgress > 1 && header.epoch == 0 {
+		h := c.readHeaderOld()
+		Log.Warnf("falling back to old stat segment header version: %+v", h)
+		c.oldHeader = true
+	}
+
+	return nil
+}
+
+func (c *statSegment) disconnect() error {
+	if err := syscall.Munmap(c.sharedHeader); err != nil {
+		Log.Warnf("unmapping shared memory failed: %v", err)
+		return fmt.Errorf("unmapping shared memory failed: %v", err)
+	}
+
+	Log.Debugf("successfuly unmapped shared memory")
+
+	return nil
+}
+
+type sharedHeaderBase struct {
+	epoch           int64
+	inProgress      int64
+	directoryOffset int64
+	errorOffset     int64
+	statsOffset     int64
+}
+
+type statSegSharedHeader struct {
+	version uint64
+	sharedHeaderBase
+}
+
+func (c *statSegment) readHeaderOld() (header statSegSharedHeader) {
+	h := (*sharedHeaderBase)(unsafe.Pointer(&c.sharedHeader[0]))
+	header.version = 0
+	header.epoch = atomic.LoadInt64(&h.epoch)
+	header.inProgress = atomic.LoadInt64(&h.inProgress)
+	header.directoryOffset = atomic.LoadInt64(&h.directoryOffset)
+	header.errorOffset = atomic.LoadInt64(&h.errorOffset)
+	header.statsOffset = atomic.LoadInt64(&h.statsOffset)
+	return
+}
+
+func (c *statSegment) readHeader() (header statSegSharedHeader) {
+	h := (*statSegSharedHeader)(unsafe.Pointer(&c.sharedHeader[0]))
+	header.version = atomic.LoadUint64(&h.version)
+	header.epoch = atomic.LoadInt64(&h.epoch)
+	header.inProgress = atomic.LoadInt64(&h.inProgress)
+	header.directoryOffset = atomic.LoadInt64(&h.directoryOffset)
+	header.errorOffset = atomic.LoadInt64(&h.errorOffset)
+	header.statsOffset = atomic.LoadInt64(&h.statsOffset)
+	return
+}
+
+func (c *statSegment) readVersion() uint64 {
+	if c.oldHeader {
+		return 0
+	}
+	header := (*statSegSharedHeader)(unsafe.Pointer(&c.sharedHeader[0]))
+	version := atomic.LoadUint64(&header.version)
+	return version
+}
+
+func (c *statSegment) readEpoch() (int64, bool) {
+	if c.oldHeader {
+		h := c.readHeaderOld()
+		return h.epoch, h.inProgress != 0
+	}
+	header := (*statSegSharedHeader)(unsafe.Pointer(&c.sharedHeader[0]))
+	epoch := atomic.LoadInt64(&header.epoch)
+	inprog := atomic.LoadInt64(&header.inProgress)
+	return epoch, inprog != 0
+}
+
+func (c *statSegment) readOffsets() (dir, err, stat int64) {
+	if c.oldHeader {
+		h := c.readHeaderOld()
+		return h.directoryOffset, h.errorOffset, h.statsOffset
+	}
+	header := (*statSegSharedHeader)(unsafe.Pointer(&c.sharedHeader[0]))
+	dirOffset := atomic.LoadInt64(&header.directoryOffset)
+	errOffset := atomic.LoadInt64(&header.errorOffset)
+	statOffset := atomic.LoadInt64(&header.statsOffset)
+	return dirOffset, errOffset, statOffset
+}
+
+type statSegAccess struct {
+	epoch int64
+}
+
+func (c *statSegment) accessStart() *statSegAccess {
+	epoch, inprog := c.readEpoch()
+	t := time.Now()
+	for inprog {
+		if time.Since(t) > maxWaitInProgress {
+			return nil
+		}
+		epoch, inprog = c.readEpoch()
+	}
+	return &statSegAccess{
+		epoch: epoch,
+	}
+}
+
+func (c *statSegment) accessEnd(acc *statSegAccess) bool {
+	epoch, inprog := c.readEpoch()
+	if acc.epoch != epoch || inprog {
+		return false
+	}
+	return true
+}
+
+type vecHeader struct {
+	length     uint64
+	vectorData [0]uint8
+}
+
+func vectorLen(v unsafe.Pointer) uint64 {
+	vec := *(*vecHeader)(unsafe.Pointer(uintptr(v) - unsafe.Sizeof(uintptr(0))))
+	return vec.length
+}
+
+//go:nosplit
+func add(p unsafe.Pointer, x uintptr) unsafe.Pointer {
+	return unsafe.Pointer(uintptr(p) + x)
+}