From 9afbecb7acf0af5876bfd4c47e95fba3e15d4289 Mon Sep 17 00:00:00 2001
From: Viktor Liu <17948409+lixmal@users.noreply.github.com>
Date: Thu, 3 Jul 2025 09:02:53 +0200
Subject: [PATCH] [client] Use unique sequence numbers for bsd routes (#4081)

updates the route manager on Unix to use a unique, incrementing sequence number for each route message instead of a fixed value.

Replace the static Seq: 1 with a call to r.getSeq()
Add an atomic seq field and the getSeq method in SysOps
---
 client/internal/routemanager/systemops/systemops.go      | 9 +++++++++
 client/internal/routemanager/systemops/systemops_unix.go | 2 +-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/client/internal/routemanager/systemops/systemops.go b/client/internal/routemanager/systemops/systemops.go
index 8caf22f81..106c520da 100644
--- a/client/internal/routemanager/systemops/systemops.go
+++ b/client/internal/routemanager/systemops/systemops.go
@@ -5,6 +5,7 @@ import (
 	"net"
 	"net/netip"
 	"sync"
+	"sync/atomic"
 
 	"github.com/netbirdio/netbird/client/iface/wgaddr"
 	"github.com/netbirdio/netbird/client/internal/routemanager/notifier"
@@ -52,6 +53,9 @@ type SysOps struct {
 	mu sync.Mutex
 	// notifier is used to notify the system of route changes (also used on mobile)
 	notifier *notifier.Notifier
+	// seq is an atomic counter for generating unique sequence numbers for route messages
+	//nolint:unused // only used on BSD systems
+	seq atomic.Uint32
 }
 
 func NewSysOps(wgInterface wgIface, notifier *notifier.Notifier) *SysOps {
@@ -61,6 +65,11 @@ func NewSysOps(wgInterface wgIface, notifier *notifier.Notifier) *SysOps {
 	}
 }
 
+//nolint:unused // only used on BSD systems
+func (r *SysOps) getSeq() int {
+	return int(r.seq.Add(1))
+}
+
 func (r *SysOps) validateRoute(prefix netip.Prefix) error {
 	addr := prefix.Addr()
 
diff --git a/client/internal/routemanager/systemops/systemops_unix.go b/client/internal/routemanager/systemops/systemops_unix.go
index f284e131b..46e5ca915 100644
--- a/client/internal/routemanager/systemops/systemops_unix.go
+++ b/client/internal/routemanager/systemops/systemops_unix.go
@@ -108,7 +108,7 @@ func (r *SysOps) buildRouteMessage(action int, prefix netip.Prefix, nexthop Next
 		Type:    action,
 		Flags:   unix.RTF_UP,
 		Version: unix.RTM_VERSION,
-		Seq:     1,
+		Seq:     r.getSeq(),
 	}
 
 	const numAddrs = unix.RTAX_NETMASK + 1