From 65842f749bbb09e779e4bc8d68ab884bacc86e63 Mon Sep 17 00:00:00 2001
From: Jonathan Rudenberg <jonathan@titanous.com>
Date: Sun, 14 Sep 2014 20:29:27 -0400
Subject: [PATCH] netlink: Extract message checks into reusable method

Signed-off-by: Jonathan Rudenberg <jonathan@titanous.com>
---
 netlink/netlink_linux.go | 62 ++++++++++++++++++++--------------------
 1 file changed, 31 insertions(+), 31 deletions(-)

diff --git a/netlink/netlink_linux.go b/netlink/netlink_linux.go
index e3579eea..74980d72 100644
--- a/netlink/netlink_linux.go
+++ b/netlink/netlink_linux.go
@@ -3,6 +3,7 @@ package netlink
 import (
 	"encoding/binary"
 	"fmt"
+	"io"
 	"net"
 	"sync/atomic"
 	"syscall"
@@ -322,35 +323,44 @@ func (s *NetlinkSocket) GetPid() (uint32, error) {
 	return 0, ErrWrongSockType
 }
 
-func (s *NetlinkSocket) HandleAck(seq uint32) error {
+func (s *NetlinkSocket) CheckMessage(m syscall.NetlinkMessage, seq, pid uint32) error {
+	if m.Header.Seq != seq {
+		return fmt.Errorf("netlink: invalid seq %d, expected %d", m.Header.Seq, seq)
+	}
+	if m.Header.Pid != pid {
+		return fmt.Errorf("netlink: wrong pid %d, expected %d", m.Header.Pid, pid)
+	}
+	if m.Header.Type == syscall.NLMSG_DONE {
+		return io.EOF
+	}
+	if m.Header.Type == syscall.NLMSG_ERROR {
+		e := int32(native.Uint32(m.Data[0:4]))
+		if e == 0 {
+			return io.EOF
+		}
+		return syscall.Errno(-e)
+	}
+	return nil
+}
 
+func (s *NetlinkSocket) HandleAck(seq uint32) error {
 	pid, err := s.GetPid()
 	if err != nil {
 		return err
 	}
 
-done:
+outer:
 	for {
 		msgs, err := s.Receive()
 		if err != nil {
 			return err
 		}
 		for _, m := range msgs {
-			if m.Header.Seq != seq {
-				return fmt.Errorf("Wrong Seq nr %d, expected %d", m.Header.Seq, seq)
-			}
-			if m.Header.Pid != pid {
-				return fmt.Errorf("Wrong pid %d, expected %d", m.Header.Pid, pid)
-			}
-			if m.Header.Type == syscall.NLMSG_DONE {
-				break done
-			}
-			if m.Header.Type == syscall.NLMSG_ERROR {
-				error := int32(native.Uint32(m.Data[0:4]))
-				if error == 0 {
-					break done
+			if err := s.CheckMessage(m, seq, pid); err != nil {
+				if err == io.EOF {
+					break outer
 				}
-				return syscall.Errno(-error)
+				return err
 			}
 		}
 	}
@@ -781,28 +791,18 @@ func NetworkGetRoutes() ([]Route, error) {
 
 	res := make([]Route, 0)
 
-done:
+outer:
 	for {
 		msgs, err := s.Receive()
 		if err != nil {
 			return nil, err
 		}
 		for _, m := range msgs {
-			if m.Header.Seq != wb.Seq {
-				return nil, fmt.Errorf("Wrong Seq nr %d, expected 1", m.Header.Seq)
-			}
-			if m.Header.Pid != pid {
-				return nil, fmt.Errorf("Wrong pid %d, expected %d", m.Header.Pid, pid)
-			}
-			if m.Header.Type == syscall.NLMSG_DONE {
-				break done
-			}
-			if m.Header.Type == syscall.NLMSG_ERROR {
-				error := int32(native.Uint32(m.Data[0:4]))
-				if error == 0 {
-					break done
+			if err := s.CheckMessage(m, wb.Seq, pid); err != nil {
+				if err == io.EOF {
+					break outer
 				}
-				return nil, syscall.Errno(-error)
+				return nil, err
 			}
 			if m.Header.Type != syscall.RTM_NEWROUTE {
 				continue