diff --git a/configure.ac b/configure.ac
index d9ad51b6ca6d..2b3b82c745ea 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1240,7 +1240,6 @@ m4_define([FRR_INCLUDES],
 #include <stdlib.h>
 #include <stddef.h>
 #include <sys/types.h>
-/* sys/conf.h depends on param.h on FBSD at least */
 #include <sys/param.h>
 /* Required for MAXSIG */
 #include <signal.h>
@@ -1251,23 +1250,8 @@ m4_define([FRR_INCLUDES],
 #include <net/if.h>
 ])dnl
 
-dnl Same applies for HAVE_NET_IF_VAR_H, which HAVE_NETINET6_ND6_H and
-dnl HAVE_NETINET_IN_VAR_H depend upon. But if_var.h depends on if.h, hence
-dnl an additional round for it.
-
-AC_CHECK_HEADERS([net/if_var.h], [], [], [FRR_INCLUDES])
-
-m4_define([FRR_INCLUDES],
-FRR_INCLUDES
-[#ifdef HAVE_NET_IF_VAR_H
-# include <net/if_var.h>
-#endif
-])dnl
-
 AC_CHECK_HEADERS([netinet/in_var.h \
-	net/if_dl.h \
-	netinet/ip_icmp.h \
-	sys/sysctl.h sys/sockio.h sys/conf.h],
+	netinet/ip_icmp.h],
 	[], [], [FRR_INCLUDES])
 
 AC_CHECK_HEADERS([ucontext.h], [], [],
@@ -1297,7 +1281,7 @@ FRR_INCLUDES
 #ifdef HAVE_NETINET_IN_VAR_H
 # include <netinet/in_var.h>
 #endif
-#ifdef HAVE_NET_IF_DL_H
+#ifndef __linux__
 # include <net/if_dl.h>
 #endif
 #include <net/route.h>
@@ -1797,15 +1781,12 @@ dnl ------------------
 dnl IPv6 header checks
 dnl ------------------
 AC_CHECK_HEADERS([ \
-	netinet6/in6_var.h netinet6/nd6.h], [], [],
+	netinet6/nd6.h], [], [],
 	FRR_INCLUDES)
 
 m4_define([FRR_INCLUDES],dnl
 FRR_INCLUDES
 [#include <netinet/icmp6.h>
-#ifdef HAVE_NETINET6_IN6_VAR_H
-# include <netinet6/in6_var.h>
-#endif
 #ifdef HAVE_NETINET6_ND6_H
 # include <netinet6/nd6.h>
 #endif
@@ -2310,7 +2291,7 @@ AC_CHECK_TYPES([
 	struct sockaddr_dl,
 	struct vifctl, struct mfcctl, struct sioc_sg_req,
 	vifi_t, struct sioc_vif_req, struct igmpmsg,
-	struct ifaliasreq, struct in6_aliasreq,
+	struct ifaliasreq,
 	struct nd_opt_adv_interval,
 	struct nd_opt_homeagent_info, struct nd_opt_adv_interval,
 	struct nd_opt_rdnss, struct nd_opt_dnssl],
diff --git a/eigrpd/eigrp_packet.c b/eigrpd/eigrp_packet.c
index 76e0da9b8efa..4daff32018bd 100644
--- a/eigrpd/eigrp_packet.c
+++ b/eigrpd/eigrp_packet.c
@@ -12,6 +12,10 @@
 
 #include <zebra.h>
 
+#ifndef __linux__
+#include <net/if_dl.h>
+#endif
+
 #include "frrevent.h"
 #include "memory.h"
 #include "linklist.h"
diff --git a/ldpd/packet.c b/ldpd/packet.c
index 42d526aa0b8b..1cf0859379f5 100644
--- a/ldpd/packet.c
+++ b/ldpd/packet.c
@@ -9,6 +9,10 @@
 
 #include <zebra.h>
 
+#ifndef __linux__
+#include <net/if_dl.h>
+#endif
+
 #include "ldpd.h"
 #include "ldpe.h"
 #include "log.h"
diff --git a/lib/prefix.h b/lib/prefix.h
index 2d679d06224f..d42a383de02c 100644
--- a/lib/prefix.h
+++ b/lib/prefix.h
@@ -7,7 +7,7 @@
 #ifndef _ZEBRA_PREFIX_H
 #define _ZEBRA_PREFIX_H
 
-#ifdef GNU_LINUX
+#ifdef __linux__
 #include <net/ethernet.h>
 #else
 #include <netinet/if_ether.h>
diff --git a/lib/sockopt.c b/lib/sockopt.c
index 003ddb72dc2d..e3fee61cb704 100644
--- a/lib/sockopt.c
+++ b/lib/sockopt.c
@@ -5,6 +5,10 @@
 
 #include <zebra.h>
 
+#ifndef __linux__
+#include <net/if_dl.h>
+#endif
+
 #include "log.h"
 #include "sockopt.h"
 #include "sockunion.h"
diff --git a/lib/sockunion.c b/lib/sockunion.c
index 13a98db07bd6..fd4fc8bf1ba5 100644
--- a/lib/sockunion.c
+++ b/lib/sockunion.c
@@ -5,6 +5,10 @@
 
 #include <zebra.h>
 
+#ifndef __linux__
+#include <net/if_dl.h>
+#endif
+
 #include "prefix.h"
 #include "vty.h"
 #include "sockunion.h"
diff --git a/lib/zebra.h b/lib/zebra.h
index bae81537bb7a..46d3c2f660c5 100644
--- a/lib/zebra.h
+++ b/lib/zebra.h
@@ -19,16 +19,6 @@
 #include <ctype.h>
 #include <sys/types.h>
 #include <sys/param.h>
-#ifdef HAVE_SYS_SYSCTL_H
-#ifdef GNU_LINUX
-#include <linux/types.h>
-#else
-#include <sys/sysctl.h>
-#endif
-#endif /* HAVE_SYS_SYSCTL_H */
-#ifdef HAVE_SYS_CONF_H
-#include <sys/conf.h>
-#endif /* HAVE_SYS_CONF_H */
 #include <sys/time.h>
 #include <time.h>
 #include <inttypes.h>
@@ -44,10 +34,6 @@
 
 #include <sys/socket.h>
 
-#ifdef HAVE_SYS_SOCKIO_H
-#include <sys/sockio.h>
-#endif /* HAVE_SYS_SOCKIO_H */
-
 #include "openbsd-tree.h"
 
 #include <netinet/in.h>
@@ -56,14 +42,6 @@
 
 #include <net/if.h>
 
-#ifdef HAVE_NET_IF_DL_H
-#include <net/if_dl.h>
-#endif /* HAVE_NET_IF_DL_H */
-
-#ifdef HAVE_NET_IF_VAR_H
-#include <net/if_var.h>
-#endif /* HAVE_NET_IF_VAR_H */
-
 #ifndef HAVE_NETLINK
 #define RT_TABLE_MAIN		0
 #define RT_TABLE_LOCAL		RT_TABLE_MAIN
@@ -76,10 +54,6 @@
 #include <netinet/in_var.h>
 #endif /* HAVE_NETINET_IN_VAR_H */
 
-#ifdef HAVE_NETINET6_IN6_VAR_H
-#include <netinet6/in6_var.h>
-#endif /* HAVE_NETINET6_IN6_VAR_H */
-
 #ifdef HAVE_NETINET6_IN_H
 #include <netinet6/in.h>
 #endif /* HAVE_NETINET6_IN_H */
diff --git a/ospf6d/ospf6_interface.c b/ospf6d/ospf6_interface.c
index e79bc3498361..2e245b1442c4 100644
--- a/ospf6d/ospf6_interface.c
+++ b/ospf6d/ospf6_interface.c
@@ -5,6 +5,10 @@
 
 #include <zebra.h>
 
+#ifndef __linux__
+#include <net/if_dl.h>
+#endif
+
 #include "memory.h"
 #include "if.h"
 #include "log.h"
diff --git a/ospfd/ospf_packet.c b/ospfd/ospf_packet.c
index 355808e09170..0f0590c270e1 100644
--- a/ospfd/ospf_packet.c
+++ b/ospfd/ospf_packet.c
@@ -6,6 +6,10 @@
 
 #include <zebra.h>
 
+#ifndef __linux__
+#include <net/if_dl.h>
+#endif
+
 #include "monotime.h"
 #include "frrevent.h"
 #include "memory.h"
diff --git a/pceplib/pcep.h b/pceplib/pcep.h
index cb7019dac6e2..7d3378c70457 100644
--- a/pceplib/pcep.h
+++ b/pceplib/pcep.h
@@ -15,7 +15,7 @@
 #include "config.h"
 #endif
 
-#if defined(linux) || defined(GNU_LINUX)
+#ifdef __linux__
 
 #define ipv6_u __in6_u
 #else
diff --git a/zebra/if_sysctl.c b/zebra/if_sysctl.c
index 28cbb0415a5c..12f8b91ef446 100644
--- a/zebra/if_sysctl.c
+++ b/zebra/if_sysctl.c
@@ -10,6 +10,8 @@
 
 #if !defined(GNU_LINUX) && !defined(OPEN_BSD)
 
+#include <sys/sysctl.h>
+
 #include "if.h"
 #include "sockunion.h"
 #include "prefix.h"
diff --git a/zebra/interface.h b/zebra/interface.h
index 5b45656bd5ac..0947a2294226 100644
--- a/zebra/interface.h
+++ b/zebra/interface.h
@@ -7,6 +7,10 @@
 #ifndef _ZEBRA_INTERFACE_H
 #define _ZEBRA_INTERFACE_H
 
+#ifndef __linux__
+#include <net/if_dl.h>
+#endif
+
 #include "redistribute.h"
 #include "vrf.h"
 #include "hook.h"
diff --git a/zebra/ioctl.c b/zebra/ioctl.c
index f89412f6d60a..2449f62e30fb 100644
--- a/zebra/ioctl.c
+++ b/zebra/ioctl.c
@@ -7,6 +7,9 @@
 #include <zebra.h>
 
 #include <sys/ioctl.h>
+#ifndef __linux__
+#include <netinet6/in6_var.h>
+#endif
 
 #include "linklist.h"
 #include "if.h"
@@ -533,12 +536,6 @@ int if_unset_flags(struct interface *ifp, uint64_t flags)
 }
 
 #ifndef LINUX_IPV6 /* Netlink has its own code */
-
-#ifdef HAVE_STRUCT_IN6_ALIASREQ
-#ifndef ND6_INFINITE_LIFETIME
-#define ND6_INFINITE_LIFETIME 0xffffffffL
-#endif /* ND6_INFINITE_LIFETIME */
-
 /*
  * Helper for interface-addr install, non-netlink
  */
@@ -614,29 +611,9 @@ static int if_unset_prefix6_ctx(const struct zebra_dplane_ctx *ctx)
 #endif
 	memcpy(&addreq.ifra_prefixmask, &mask, sizeof(struct sockaddr_in6));
 
-#ifdef HAVE_STRUCT_IF6_ALIASREQ_IFRA_LIFETIME
-	addreq.ifra_lifetime.ia6t_pltime = ND6_INFINITE_LIFETIME;
-	addreq.ifra_lifetime.ia6t_vltime = ND6_INFINITE_LIFETIME;
-#endif
-
 	ret = if_ioctl_ipv6(SIOCDIFADDR_IN6, (caddr_t)&addreq);
 	if (ret < 0)
 		return ret;
 	return 0;
 }
-#else
-/* The old, pre-dataplane code here just returned, so we're retaining that
- * choice.
- */
-static int if_set_prefix6_ctx(const struct zebra_dplane_ctx *ctx)
-{
-	return 0;
-}
-
-static int if_unset_prefix6_ctx(const struct zebra_dplane_ctx *ctx)
-{
-	return 0;
-}
-#endif /* HAVE_STRUCT_IN6_ALIASREQ */
-
 #endif /* LINUX_IPV6 */
diff --git a/zebra/ipforward_sysctl.c b/zebra/ipforward_sysctl.c
index bc9d12b5225a..fc2571d2bd88 100644
--- a/zebra/ipforward_sysctl.c
+++ b/zebra/ipforward_sysctl.c
@@ -7,6 +7,8 @@
 
 #if !defined(GNU_LINUX)
 
+#include <sys/sysctl.h>
+
 #include "privs.h"
 #include "zebra/ipforward.h"
 #include "zebra/zebra_errors.h"
diff --git a/zebra/rtread_sysctl.c b/zebra/rtread_sysctl.c
index 8e2d13fafff0..2f073f6c303d 100644
--- a/zebra/rtread_sysctl.c
+++ b/zebra/rtread_sysctl.c
@@ -10,6 +10,8 @@
 
 #if !defined(GNU_LINUX)
 
+#include <sys/sysctl.h>
+
 #include "memory.h"
 #include "log.h"
 #include "vrf.h"
diff --git a/zebra/table_manager.h b/zebra/table_manager.h
index f16efdd6266b..11225b756ddc 100644
--- a/zebra/table_manager.h
+++ b/zebra/table_manager.h
@@ -21,7 +21,7 @@ extern "C" {
 /* routing table identifiers
  *
  */
-#if !defined(GNU_LINUX)
+#ifndef __linux__
 /* BSD systems
  */
 #define RT_TABLE_ID_MAIN 0
@@ -33,7 +33,7 @@ extern "C" {
 #define RT_TABLE_ID_DEFAULT 253
 #define RT_TABLE_ID_COMPAT  252
 #define RT_TABLE_ID_UNSPEC  0
-#endif /* !def(GNU_LINUX) */
+#endif /* !__linux__ */
 
 /*
  * Table chunk struct