Update

vendor/github.com/mdlayher/netlink/debug_linux.go

@@ -0,0 +1,196 @@
+//go:build linux
+
+package netlink
+
+import (
+	"encoding/binary"
+	"fmt"
+	"io"
+	"log"
+	"os"
+	"strconv"
+	"strings"
+	"syscall"
+	"unsafe"
+
+	"golang.org/x/sys/unix"
+)
+
+// newDebugger creates a debugger by parsing key=value arguments.
+func newDebugger(args []string) *debugger {
+	d := &debugger{
+		Log:    log.New(os.Stderr, "nl: ", 0),
+		Level:  1,
+		Format: "mnl",
+	}
+	for _, a := range args {
+		kv := strings.Split(a, "=")
+		if len(kv) != 2 {
+			continue
+		}
+		switch kv[0] {
+		case "level":
+			level, err := strconv.Atoi(kv[1])
+			if err != nil {
+				panicf("netlink: invalid NLDEBUG level: %q", a)
+			}
+			d.Level = level
+		case "format":
+			d.Format = kv[1]
+		}
+	}
+	return d
+}
+
+// debugf prints debugging information at the specified level, if d.Level is high enough to print the message.
+func (d *debugger) debugf(level int, format string, v ...any) {
+	if d.Level < level {
+		return
+	}
+	switch d.Format {
+	case "mnl":
+		colorize := true
+		_, err := unix.IoctlGetWinsize(int(os.Stdout.Fd()), unix.TIOCGWINSZ)
+		if err != nil {
+			colorize = false
+		}
+		for _, iface := range v {
+			if msg, ok := iface.(Message); ok {
+				nlmsgFprintf(d.Log.Writer(), msg, colorize)
+			} else {
+				d.Log.Printf(format, v...)
+			}
+		}
+	default:
+		d.Log.Printf(format, v...)
+	}
+}
+
+// nlmsgFprintfHeader prints the netlink message header to fd.
+func nlmsgFprintfHeader(fd io.Writer, nlh Header) {
+	fmt.Fprintf(fd, "----------------\t------------------\n")
+	fmt.Fprintf(fd, "|  %010d  |\t| message length |\n", nlh.Length)
+	fmt.Fprintf(fd, "| %05d | %s%s%s%s |\t|  type | flags  |\n",
+		nlh.Type,
+		ternary(nlh.Flags&Request != 0, "R", "-"),
+		ternary(nlh.Flags&Multi != 0, "M", "-"),
+		ternary(nlh.Flags&Acknowledge != 0, "A", "-"),
+		ternary(nlh.Flags&Echo != 0, "E", "-"),
+	)
+	fmt.Fprintf(fd, "|  %010d  |\t| sequence number|\n", nlh.Sequence)
+	fmt.Fprintf(fd, "|  %010d  |\t|     port ID    |\n", nlh.PID)
+	fmt.Fprintf(fd, "----------------\t------------------\n")
+}
+
+// nlmsgFprintf prints a single Message for netlink errors and attributes.
+func nlmsgFprintf(fd io.Writer, m Message, colorize bool) {
+	var hasHeader bool
+	nlmsgFprintfHeader(fd, m.Header)
+	switch {
+	case m.Header.Type == Error:
+		hasHeader = true
+	case m.Header.Type == Done && m.Header.Flags&Multi != 0:
+		if len(m.Data) == 0 {
+			return
+		}
+	default:
+		// Neither, nothing to do.
+	}
+	// Errno occupies 4 bytes.
+	const endErrno = 4
+	if len(m.Data) < endErrno {
+		return
+	}
+
+	c := int32(binary.NativeEndian.Uint32(m.Data[:endErrno]))
+	if c != 0 {
+		b := m.Data[0:4]
+		fmt.Fprintf(fd, "| %.2x %.2x %.2x %.2x  |\t",
+			0xff&b[0], 0xff&b[1],
+			0xff&b[2], 0xff&b[3])
+		fmt.Fprintf(fd, "|  extra header  |\n")
+	}
+
+	// Flags indicate an extended acknowledgement. The type/flags combination
+	// checked above determines the offset where the TLVs occur.
+	var off int
+	if hasHeader {
+		// There is an nlmsghdr preceding the TLVs.
+		if len(m.Data) < endErrno+nlmsgHeaderLen {
+			return
+		}
+		// The TLVs should be at the offset indicated by the nlmsghdr.length,
+		// plus the offset where the header began. But make sure the calculated
+		// offset is still in-bounds.
+		h := *(*Header)(unsafe.Pointer(&m.Data[endErrno : endErrno+nlmsgHeaderLen][0]))
+		off = endErrno + int(h.Length)
+		if len(m.Data) < off {
+			return
+		}
+	} else {
+		// There is no nlmsghdr preceding the TLVs, parse them directly.
+		off = endErrno
+	}
+
+	data := m.Data[off:]
+	for i := 0; i < len(data); {
+		// Make sure there's at least a header's worth of data to read on each iteration.
+		if len(data[i:]) < nlaHeaderLen {
+			break
+		}
+		// Extract the length of the attribute.
+		l := int(binary.NativeEndian.Uint16(data[i:]))
+		// extract the type
+		t := binary.NativeEndian.Uint16(data[i+2:])
+		// print attribute header
+		if colorize {
+			fmt.Fprintf(fd, "|\033[1;31m%05d|\033[1;32m%s%s|\033[1;34m%05d\033[0m|\t",
+				l,
+				ternary(t&syscall.NLA_F_NESTED != 0, "N", "-"),
+				ternary(t&syscall.NLA_F_NET_BYTEORDER != 0, "B", "-"),
+				t&attrTypeMask)
+			fmt.Fprintf(fd, "|len |flags| type|\n")
+		} else {
+			fmt.Fprintf(fd, "|%05d|%s%s|%05d|\t",
+				l,
+				ternary(t&syscall.NLA_F_NESTED != 0, "N", "-"),
+				ternary(t&syscall.NLA_F_NET_BYTEORDER != 0, "B", "-"),
+				t&attrTypeMask)
+			fmt.Fprintf(fd, "|len |flags| type|\n")
+		}
+
+		nextAttr := i + nlaAlign(l)
+		i += nlaHeaderLen
+
+		// Ignore zero-length attributes.
+		if l == 0 {
+			continue
+		}
+		// If nested check the next attribute
+		if t&syscall.NLA_F_NESTED != 0 {
+			continue
+		}
+		// Print the remaining attributes bytes
+		for ; i < nextAttr; i += 4 {
+			fmt.Fprintf(fd, "| %.2x %.2x %.2x %.2x  |\t",
+				0xff&data[i], 0xff&data[i+1],
+				0xff&data[i+2], 0xff&data[i+3])
+			fmt.Fprintf(fd, "|      data      |")
+			fmt.Fprintf(fd, "\t %s %s %s %s\n",
+				ternary(strconv.IsPrint(rune(data[i])), string(data[i]), " "),
+				ternary(strconv.IsPrint(rune(data[i+1])), string(data[i+1]), " "),
+				ternary(strconv.IsPrint(rune(data[i+2])), string(data[i+2]), " "),
+				ternary(strconv.IsPrint(rune(data[i+3])), string(data[i+3]), " "),
+			)
+		}
+	}
+	fmt.Fprintf(fd, "----------------\t------------------\n")
+}
+
+// ternary returns iftrue if cond is true, else iffalse.
+func ternary(cond bool, iftrue string, iffalse string) string {
+	if cond {
+		return iftrue
+	}
+	return iffalse
+}