From a80cd4707464cedb526eb72e7704b097af20beb7 Mon Sep 17 00:00:00 2001
From: "Alexander V. Chernikov" <melifaro@ipfw.ru>
Date: Fri, 9 Dec 2022 15:59:06 +0100
Subject: [PATCH] Netlink on FreeBSD support
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Netlink support was added to FreeBSD recently. It is not as full-featured
as its Linux counterpart yet, however the added subset is enough to make
a routing daemon work. Specifically, it supports multiple tables,
multipath, nexthops and nexthops groups. No MPLS support yet.

The attached change adds 'bsd-netlink’ sysconf target, allowing to build
both netlink & rtsock versions on FreeBSD.
---
 sysdep/cf/bsd-netlink.h | 34 ++++++++++++++++++++++++++++++++++
 sysdep/cf/linux.h       |  2 ++
 sysdep/linux/netlink.c  |  7 ++++++-
 3 files changed, 42 insertions(+), 1 deletion(-)
 create mode 100644 sysdep/cf/bsd-netlink.h

diff --git a/sysdep/cf/bsd-netlink.h b/sysdep/cf/bsd-netlink.h
new file mode 100644
index 00000000..09149dc4
--- /dev/null
+++ b/sysdep/cf/bsd-netlink.h
@@ -0,0 +1,34 @@
+/*
+ *	Configuration for FreeBSD based systems with netlink support
+ *
+ *	(c) 2022 Alexander Chernikov <melifaro@FreeBSD.org>
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+#define CONFIG_AUTO_ROUTES
+#define CONFIG_SELF_CONSCIOUS
+#define CONFIG_MULTIPLE_TABLES
+#define CONFIG_SINGLE_ROUTE
+
+#define CONFIG_SKIP_MC_BIND
+#define CONFIG_NO_IFACE_BIND
+#define CONFIG_USE_HDRINCL
+
+#define CONFIG_INCLUDE_SYSIO_H "sysdep/bsd/sysio.h"
+#define CONFIG_INCLUDE_KRTSYS_H "sysdep/linux/krt-sys.h"
+
+#define	CONFIG_FREEBSD_NETLINK
+
+#ifndef	AF_MPLS
+#define	AF_MPLS	39
+#endif
+
+#ifndef	SO_RCVBUFFORCE
+#define	SO_RCVBUFFORCE	SO_RCVBUF
+#endif
+
+/*
+Link: sysdep/unix
+Link: sysdep/bsd-netlink
+ */
diff --git a/sysdep/cf/linux.h b/sysdep/cf/linux.h
index 56ecf017..85598c10 100644
--- a/sysdep/cf/linux.h
+++ b/sysdep/cf/linux.h
@@ -17,6 +17,8 @@
 #define CONFIG_INCLUDE_SYSIO_H "sysdep/linux/sysio.h"
 #define CONFIG_INCLUDE_KRTSYS_H "sysdep/linux/krt-sys.h"
 
+#define CONFIG_LINUX_NETLINK
+
 #define CONFIG_RESTRICTED_PRIVILEGES
 #define CONFIG_INCLUDE_SYSPRIV_H "sysdep/linux/syspriv.h"
 
diff --git a/sysdep/linux/netlink.c b/sysdep/linux/netlink.c
index d9e81c10..dcb25911 100644
--- a/sysdep/linux/netlink.c
+++ b/sysdep/linux/netlink.c
@@ -6,7 +6,6 @@
  *	Can be freely distributed and used under the terms of the GNU GPL.
  */
 
-#include <alloca.h>
 #include <stdio.h>
 #include <unistd.h>
 #include <fcntl.h>
@@ -28,10 +27,16 @@
 #include "lib/hash.h"
 #include "conf/conf.h"
 
+#ifdef CONFIG_LINUX_NETLINK
 #include <asm/types.h>
 #include <linux/if.h>
 #include <linux/netlink.h>
 #include <linux/rtnetlink.h>
+#endif
+#ifdef CONFIG_FREEBSD_NETLINK
+#include <netlink/netlink.h>
+#include <netlink/netlink_route.h>
+#endif
 
 #ifdef HAVE_MPLS_KERNEL
 #include <linux/lwtunnel.h>