From d9882a62ff6e4e06e8244d5bdf9c294680981d6a Mon Sep 17 00:00:00 2001
From: Alexandr Morozov <lk4d4math@gmail.com>
Date: Fri, 30 May 2014 13:12:02 +0400
Subject: [PATCH] Atomically increment sequence in pkg/netlink

Docker-DCO-1.1-Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com> (github: LK4D4)
---
 netlink/netlink_linux.go | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/netlink/netlink_linux.go b/netlink/netlink_linux.go
index 21d4593..14e30aa 100644
--- a/netlink/netlink_linux.go
+++ b/netlink/netlink_linux.go
@@ -7,6 +7,7 @@ import (
 	"fmt"
 	"math/rand"
 	"net"
+	"sync/atomic"
 	"syscall"
 	"unsafe"
 )
@@ -22,7 +23,7 @@ const (
 	SIOC_BRADDIF   = 0x89a2
 )
 
-var nextSeqNr int
+var nextSeqNr uint32
 
 type ifreqHwaddr struct {
 	IfrnName   [16]byte
@@ -42,11 +43,6 @@ func nativeEndian() binary.ByteOrder {
 	return binary.LittleEndian
 }
 
-func getSeq() int {
-	nextSeqNr = nextSeqNr + 1
-	return nextSeqNr
-}
-
 func getIpFamily(ip net.IP) int {
 	if len(ip) <= net.IPv4len {
 		return syscall.AF_INET
@@ -266,7 +262,7 @@ func newNetlinkRequest(proto, flags int) *NetlinkRequest {
 			Len:   uint32(syscall.NLMSG_HDRLEN),
 			Type:  uint16(proto),
 			Flags: syscall.NLM_F_REQUEST | uint16(flags),
-			Seq:   uint32(getSeq()),
+			Seq:   atomic.AddUint32(&nextSeqNr, 1),
 		},
 	}
 }