Merge pull request #15082 from louis-6wind/fix-iff-lower-up

lib: take into account the Linux IFF_LOWER_UP flag

9 files changed, 840 insertions, 14 deletions

diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h
new file mode 100644
index 000000000..72393a8c1
--- /dev/null
+++ b/include/linux/compiler_types.h
@@ -0,0 +1,246 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __LINUX_COMPILER_TYPES_H
+#define __LINUX_COMPILER_TYPES_H
+
+#ifndef __ASSEMBLY__
+
+#ifdef __CHECKER__
+# define __user		__attribute__((noderef, address_space(1)))
+# define __kernel	__attribute__((address_space(0)))
+# define __safe		__attribute__((safe))
+# define __force	__attribute__((force))
+# define __nocast	__attribute__((nocast))
+# define __iomem	__attribute__((noderef, address_space(2)))
+# define __must_hold(x)	__attribute__((context(x,1,1)))
+# define __acquires(x)	__attribute__((context(x,0,1)))
+# define __releases(x)	__attribute__((context(x,1,0)))
+# define __acquire(x)	__context__(x,1)
+# define __release(x)	__context__(x,-1)
+# define __cond_lock(x,c)	((c) ? ({ __acquire(x); 1; }) : 0)
+# define __percpu	__attribute__((noderef, address_space(3)))
+# define __rcu		__attribute__((noderef, address_space(4)))
+# define __private	__attribute__((noderef))
+extern void __chk_user_ptr(const volatile void __user *);
+extern void __chk_io_ptr(const volatile void __iomem *);
+# define ACCESS_PRIVATE(p, member) (*((typeof((p)->member) __force *) &(p)->member))
+#else /* __CHECKER__ */
+# ifdef STRUCTLEAK_PLUGIN
+#  define __user __attribute__((user))
+# else
+#  define __user
+# endif
+# define __kernel
+# define __safe
+# define __force
+# define __nocast
+# define __iomem
+# define __chk_user_ptr(x) (void)0
+# define __chk_io_ptr(x) (void)0
+# define __builtin_warning(x, y...) (1)
+# define __must_hold(x)
+# define __acquires(x)
+# define __releases(x)
+# define __acquire(x) (void)0
+# define __release(x) (void)0
+# define __cond_lock(x,c) (c)
+# define __percpu
+# define __rcu
+# define __private
+# define ACCESS_PRIVATE(p, member) ((p)->member)
+#endif /* __CHECKER__ */
+
+/* Indirect macros required for expanded argument pasting, eg. __LINE__. */
+#define ___PASTE(a,b) a##b
+#define __PASTE(a,b) ___PASTE(a,b)
+
+#ifdef __KERNEL__
+
+/* Attributes */
+#include <linux/compiler_attributes.h>
+
+/* Compiler specific macros. */
+#ifdef __clang__
+#include <linux/compiler-clang.h>
+#elif defined(__INTEL_COMPILER)
+#include <linux/compiler-intel.h>
+#elif defined(__GNUC__)
+/* The above compilers also define __GNUC__, so order is important here. */
+#include <linux/compiler-gcc.h>
+#else
+#error "Unknown compiler"
+#endif
+
+/*
+ * Some architectures need to provide custom definitions of macros provided
+ * by linux/compiler-*.h, and can do so using asm/compiler.h. We include that
+ * conditionally rather than using an asm-generic wrapper in order to avoid
+ * build failures if any C compilation, which will include this file via an
+ * -include argument in c_flags, occurs prior to the asm-generic wrappers being
+ * generated.
+ */
+#ifdef CONFIG_HAVE_ARCH_COMPILER_H
+#include <asm/compiler.h>
+#endif
+
+struct ftrace_branch_data {
+	const char *func;
+	const char *file;
+	unsigned line;
+	union {
+		struct {
+			unsigned long correct;
+			unsigned long incorrect;
+		};
+		struct {
+			unsigned long miss;
+			unsigned long hit;
+		};
+		unsigned long miss_hit[2];
+	};
+};
+
+struct ftrace_likely_data {
+	struct ftrace_branch_data	data;
+	unsigned long			constant;
+};
+
+#ifdef CONFIG_ENABLE_MUST_CHECK
+#define __must_check		__attribute__((__warn_unused_result__))
+#else
+#define __must_check
+#endif
+
+#if defined(CC_USING_HOTPATCH)
+#define notrace			__attribute__((hotpatch(0, 0)))
+#elif defined(CC_USING_PATCHABLE_FUNCTION_ENTRY)
+#define notrace			__attribute__((patchable_function_entry(0, 0)))
+#else
+#define notrace			__attribute__((__no_instrument_function__))
+#endif
+
+/*
+ * it doesn't make sense on ARM (currently the only user of __naked)
+ * to trace naked functions because then mcount is called without
+ * stack and frame pointer being set up and there is no chance to
+ * restore the lr register to the value before mcount was called.
+ */
+#define __naked			__attribute__((__naked__)) notrace
+
+#define __compiler_offsetof(a, b)	__builtin_offsetof(a, b)
+
+/*
+ * Force always-inline if the user requests it so via the .config.
+ * Prefer gnu_inline, so that extern inline functions do not emit an
+ * externally visible function. This makes extern inline behave as per gnu89
+ * semantics rather than c99. This prevents multiple symbol definition errors
+ * of extern inline functions at link time.
+ * A lot of inline functions can cause havoc with function tracing.
+ * Do not use __always_inline here, since currently it expands to inline again
+ * (which would break users of __always_inline).
+ */
+#if !defined(CONFIG_OPTIMIZE_INLINING)
+#define inline inline __attribute__((__always_inline__)) __gnu_inline \
+	__inline_maybe_unused notrace
+#else
+#define inline inline                                    __gnu_inline \
+	__inline_maybe_unused notrace
+#endif
+
+/*
+ * gcc provides both __inline__ and __inline as alternate spellings of
+ * the inline keyword, though the latter is undocumented. New kernel
+ * code should only use the inline spelling, but some existing code
+ * uses __inline__. Since we #define inline above, to ensure
+ * __inline__ has the same semantics, we need this #define.
+ *
+ * However, the spelling __inline is strictly reserved for referring
+ * to the bare keyword.
+ */
+#define __inline__ inline
+
+/*
+ * GCC does not warn about unused static inline functions for -Wunused-function.
+ * Suppress the warning in clang as well by using __maybe_unused, but enable it
+ * for W=1 build. This will allow clang to find unused functions. Remove the
+ * __inline_maybe_unused entirely after fixing most of -Wunused-function warnings.
+ */
+#ifdef KBUILD_EXTRA_WARN1
+#define __inline_maybe_unused
+#else
+#define __inline_maybe_unused __maybe_unused
+#endif
+
+/*
+ * Rather then using noinline to prevent stack consumption, use
+ * noinline_for_stack instead.  For documentation reasons.
+ */
+#define noinline_for_stack noinline
+
+#endif /* __KERNEL__ */
+
+#endif /* __ASSEMBLY__ */
+
+/*
+ * The below symbols may be defined for one or more, but not ALL, of the above
+ * compilers. We don't consider that to be an error, so set them to nothing.
+ * For example, some of them are for compiler specific plugins.
+ */
+#ifndef __latent_entropy
+# define __latent_entropy
+#endif
+
+#ifndef __randomize_layout
+# define __randomize_layout __designated_init
+#endif
+
+#ifndef __no_randomize_layout
+# define __no_randomize_layout
+#endif
+
+#ifndef randomized_struct_fields_start
+# define randomized_struct_fields_start
+# define randomized_struct_fields_end
+#endif
+
+#ifndef asm_volatile_goto
+#define asm_volatile_goto(x...) asm goto(x)
+#endif
+
+#ifdef CONFIG_CC_HAS_ASM_INLINE
+#define asm_inline asm __inline
+#else
+#define asm_inline asm
+#endif
+
+#ifndef __no_fgcse
+# define __no_fgcse
+#endif
+
+/* Are two types/vars the same type (ignoring qualifiers)? */
+#define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
+
+/* Is this type a native word size -- useful for atomic operations */
+#define __native_word(t) \
+	(sizeof(t) == sizeof(char) || sizeof(t) == sizeof(short) || \
+	 sizeof(t) == sizeof(int) || sizeof(t) == sizeof(long))
+
+/* Helpers for emitting diagnostics in pragmas. */
+#ifndef __diag
+#define __diag(string)
+#endif
+
+#ifndef __diag_GCC
+#define __diag_GCC(version, severity, string)
+#endif
+
+#define __diag_push()	__diag(push)
+#define __diag_pop()	__diag(pop)
+
+#define __diag_ignore(compiler, version, option, comment) \
+	__diag_ ## compiler(version, ignore, option)
+#define __diag_warn(compiler, version, option, comment) \
+	__diag_ ## compiler(version, warn, option)
+#define __diag_error(compiler, version, option, comment) \
+	__diag_ ## compiler(version, error, option)
+
+#endif /* __LINUX_COMPILER_TYPES_H */
diff --git a/include/linux/if.h b/include/linux/if.h
new file mode 100644
index 000000000..a8ccf6d17
--- /dev/null
+++ b/include/linux/if.h
@@ -0,0 +1,296 @@
+/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
+/*
+ * INET		An implementation of the TCP/IP protocol suite for the LINUX
+ *		operating system.  INET is implemented using the  BSD Socket
+ *		interface as the means of communication with the user level.
+ *
+ *		Global definitions for the INET interface module.
+ *
+ * Version:	@(#)if.h	1.0.2	04/18/93
+ *
+ * Authors:	Original taken from Berkeley UNIX 4.3, (c) UCB 1982-1988
+ *		Ross Biro
+ *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
+ *
+ *		This program is free software; you can redistribute it and/or
+ *		modify it under the terms of the GNU General Public License
+ *		as published by the Free Software Foundation; either version
+ *		2 of the License, or (at your option) any later version.
+ */
+#ifndef _LINUX_IF_H
+#define _LINUX_IF_H
+
+#include <linux/libc-compat.h>          /* for compatibility with glibc */
+#include <linux/types.h>		/* for "__kernel_caddr_t" et al	*/
+#include <linux/socket.h>		/* for "struct sockaddr" et al	*/
+#include <linux/compiler_types.h>		/* for "__user" et al           */
+
+#ifndef __KERNEL__
+#include <sys/socket.h>			/* for struct sockaddr.		*/
+#endif
+
+#if __UAPI_DEF_IF_IFNAMSIZ
+#define	IFNAMSIZ	16
+#endif /* __UAPI_DEF_IF_IFNAMSIZ */
+#define	IFALIASZ	256
+#define	ALTIFNAMSIZ	128
+#include <linux/hdlc/ioctl.h>
+
+/* For glibc compatibility. An empty enum does not compile. */
+#if __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO != 0 || \
+    __UAPI_DEF_IF_NET_DEVICE_FLAGS != 0
+/**
+ * enum net_device_flags - &struct net_device flags
+ *
+ * These are the &struct net_device flags, they can be set by drivers, the
+ * kernel and some can be triggered by userspace. Userspace can query and
+ * set these flags using userspace utilities but there is also a sysfs
+ * entry available for all dev flags which can be queried and set. These flags
+ * are shared for all types of net_devices. The sysfs entries are available
+ * via /sys/class/net/<dev>/flags. Flags which can be toggled through sysfs
+ * are annotated below, note that only a few flags can be toggled and some
+ * other flags are always preserved from the original net_device flags
+ * even if you try to set them via sysfs. Flags which are always preserved
+ * are kept under the flag grouping @IFF_VOLATILE. Flags which are volatile
+ * are annotated below as such.
+ *
+ * You should have a pretty good reason to be extending these flags.
+ *
+ * @IFF_UP: interface is up. Can be toggled through sysfs.
+ * @IFF_BROADCAST: broadcast address valid. Volatile.
+ * @IFF_DEBUG: turn on debugging. Can be toggled through sysfs.
+ * @IFF_LOOPBACK: is a loopback net. Volatile.
+ * @IFF_POINTOPOINT: interface is has p-p link. Volatile.
+ * @IFF_NOTRAILERS: avoid use of trailers. Can be toggled through sysfs.
+ *	Volatile.
+ * @IFF_RUNNING: interface RFC2863 OPER_UP. Volatile.
+ * @IFF_NOARP: no ARP protocol. Can be toggled through sysfs. Volatile.
+ * @IFF_PROMISC: receive all packets. Can be toggled through sysfs.
+ * @IFF_ALLMULTI: receive all multicast packets. Can be toggled through
+ *	sysfs.
+ * @IFF_MASTER: master of a load balancer. Volatile.
+ * @IFF_SLAVE: slave of a load balancer. Volatile.
+ * @IFF_MULTICAST: Supports multicast. Can be toggled through sysfs.
+ * @IFF_PORTSEL: can set media type. Can be toggled through sysfs.
+ * @IFF_AUTOMEDIA: auto media select active. Can be toggled through sysfs.
+ * @IFF_DYNAMIC: dialup device with changing addresses. Can be toggled
+ *	through sysfs.
+ * @IFF_LOWER_UP: driver signals L1 up. Volatile.
+ * @IFF_DORMANT: driver signals dormant. Volatile.
+ * @IFF_ECHO: echo sent packets. Volatile.
+ */
+enum net_device_flags {
+/* for compatibility with glibc net/if.h */
+#if __UAPI_DEF_IF_NET_DEVICE_FLAGS
+	IFF_UP				= 1<<0,  /* sysfs */
+	IFF_BROADCAST			= 1<<1,  /* volatile */
+	IFF_DEBUG			= 1<<2,  /* sysfs */
+	IFF_LOOPBACK			= 1<<3,  /* volatile */
+	IFF_POINTOPOINT			= 1<<4,  /* volatile */
+	IFF_NOTRAILERS			= 1<<5,  /* sysfs */
+	IFF_RUNNING			= 1<<6,  /* volatile */
+	IFF_NOARP			= 1<<7,  /* sysfs */
+	IFF_PROMISC			= 1<<8,  /* sysfs */
+	IFF_ALLMULTI			= 1<<9,  /* sysfs */
+	IFF_MASTER			= 1<<10, /* volatile */
+	IFF_SLAVE			= 1<<11, /* volatile */
+	IFF_MULTICAST			= 1<<12, /* sysfs */
+	IFF_PORTSEL			= 1<<13, /* sysfs */
+	IFF_AUTOMEDIA			= 1<<14, /* sysfs */
+	IFF_DYNAMIC			= 1<<15, /* sysfs */
+#endif /* __UAPI_DEF_IF_NET_DEVICE_FLAGS */
+#if __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO
+	IFF_LOWER_UP			= 1<<16, /* volatile */
+	IFF_DORMANT			= 1<<17, /* volatile */
+	IFF_ECHO			= 1<<18, /* volatile */
+#endif /* __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO */
+};
+#endif /* __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO != 0 || __UAPI_DEF_IF_NET_DEVICE_FLAGS != 0 */
+
+/* for compatibility with glibc net/if.h */
+#if __UAPI_DEF_IF_NET_DEVICE_FLAGS
+#define IFF_UP				IFF_UP
+#define IFF_BROADCAST			IFF_BROADCAST
+#define IFF_DEBUG			IFF_DEBUG
+#define IFF_LOOPBACK			IFF_LOOPBACK
+#define IFF_POINTOPOINT			IFF_POINTOPOINT
+#define IFF_NOTRAILERS			IFF_NOTRAILERS
+#define IFF_RUNNING			IFF_RUNNING
+#define IFF_NOARP			IFF_NOARP
+#define IFF_PROMISC			IFF_PROMISC
+#define IFF_ALLMULTI			IFF_ALLMULTI
+#define IFF_MASTER			IFF_MASTER
+#define IFF_SLAVE			IFF_SLAVE
+#define IFF_MULTICAST			IFF_MULTICAST
+#define IFF_PORTSEL			IFF_PORTSEL
+#define IFF_AUTOMEDIA			IFF_AUTOMEDIA
+#define IFF_DYNAMIC			IFF_DYNAMIC
+#endif /* __UAPI_DEF_IF_NET_DEVICE_FLAGS */
+
+#if __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO
+#define IFF_LOWER_UP			IFF_LOWER_UP
+#define IFF_DORMANT			IFF_DORMANT
+#define IFF_ECHO			IFF_ECHO
+#endif /* __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO */
+
+#define IFF_VOLATILE	(IFF_LOOPBACK|IFF_POINTOPOINT|IFF_BROADCAST|IFF_ECHO|\
+		IFF_MASTER|IFF_SLAVE|IFF_RUNNING|IFF_LOWER_UP|IFF_DORMANT)
+
+#define IF_GET_IFACE	0x0001		/* for querying only */
+#define IF_GET_PROTO	0x0002
+
+/* For definitions see hdlc.h */
+#define IF_IFACE_V35	0x1000		/* V.35 serial interface	*/
+#define IF_IFACE_V24	0x1001		/* V.24 serial interface	*/
+#define IF_IFACE_X21	0x1002		/* X.21 serial interface	*/
+#define IF_IFACE_T1	0x1003		/* T1 telco serial interface	*/
+#define IF_IFACE_E1	0x1004		/* E1 telco serial interface	*/
+#define IF_IFACE_SYNC_SERIAL 0x1005	/* can't be set by software	*/
+#define IF_IFACE_X21D   0x1006          /* X.21 Dual Clocking (FarSite) */
+
+/* For definitions see hdlc.h */
+#define IF_PROTO_HDLC	0x2000		/* raw HDLC protocol		*/
+#define IF_PROTO_PPP	0x2001		/* PPP protocol			*/
+#define IF_PROTO_CISCO	0x2002		/* Cisco HDLC protocol		*/
+#define IF_PROTO_FR	0x2003		/* Frame Relay protocol		*/
+#define IF_PROTO_FR_ADD_PVC 0x2004	/*    Create FR PVC		*/
+#define IF_PROTO_FR_DEL_PVC 0x2005	/*    Delete FR PVC		*/
+#define IF_PROTO_X25	0x2006		/* X.25				*/
+#define IF_PROTO_HDLC_ETH 0x2007	/* raw HDLC, Ethernet emulation	*/
+#define IF_PROTO_FR_ADD_ETH_PVC 0x2008	/*  Create FR Ethernet-bridged PVC */
+#define IF_PROTO_FR_DEL_ETH_PVC 0x2009	/*  Delete FR Ethernet-bridged PVC */
+#define IF_PROTO_FR_PVC	0x200A		/* for reading PVC status	*/
+#define IF_PROTO_FR_ETH_PVC 0x200B
+#define IF_PROTO_RAW    0x200C          /* RAW Socket                   */
+
+/* RFC 2863 operational status */
+enum {
+	IF_OPER_UNKNOWN,
+	IF_OPER_NOTPRESENT,
+	IF_OPER_DOWN,
+	IF_OPER_LOWERLAYERDOWN,
+	IF_OPER_TESTING,
+	IF_OPER_DORMANT,
+	IF_OPER_UP,
+};
+
+/* link modes */
+enum {
+	IF_LINK_MODE_DEFAULT,
+	IF_LINK_MODE_DORMANT,	/* limit upward transition to dormant */
+};
+
+/*
+ *	Device mapping structure. I'd just gone off and designed a 
+ *	beautiful scheme using only loadable modules with arguments
+ *	for driver options and along come the PCMCIA people 8)
+ *
+ *	Ah well. The get() side of this is good for WDSETUP, and it'll
+ *	be handy for debugging things. The set side is fine for now and
+ *	being very small might be worth keeping for clean configuration.
+ */
+
+/* for compatibility with glibc net/if.h */
+#if __UAPI_DEF_IF_IFMAP
+struct ifmap {
+	unsigned long mem_start;
+	unsigned long mem_end;
+	unsigned short base_addr; 
+	unsigned char irq;
+	unsigned char dma;
+	unsigned char port;
+	/* 3 bytes spare */
+};
+#endif /* __UAPI_DEF_IF_IFMAP */
+
+struct if_settings {
+	unsigned int type;	/* Type of physical device or protocol */
+	unsigned int size;	/* Size of the data allocated by the caller */
+	union {
+		/* {atm/eth/dsl}_settings anyone ? */
+		raw_hdlc_proto		__user *raw_hdlc;
+		cisco_proto		__user *cisco;
+		fr_proto		__user *fr;
+		fr_proto_pvc		__user *fr_pvc;
+		fr_proto_pvc_info	__user *fr_pvc_info;
+
+		/* interface settings */
+		sync_serial_settings	__user *sync;
+		te1_settings		__user *te1;
+	} ifs_ifsu;
+};
+
+/*
+ * Interface request structure used for socket
+ * ioctl's.  All interface ioctl's must have parameter
+ * definitions which begin with ifr_name.  The
+ * remainder may be interface specific.
+ */
+
+/* for compatibility with glibc net/if.h */
+#if __UAPI_DEF_IF_IFREQ
+struct ifreq {
+#define IFHWADDRLEN	6
+	union
+	{
+		char	ifrn_name[IFNAMSIZ];		/* if name, e.g. "en0" */
+	} ifr_ifrn;
+	
+	union {
+		struct	sockaddr ifru_addr;
+		struct	sockaddr ifru_dstaddr;
+		struct	sockaddr ifru_broadaddr;
+		struct	sockaddr ifru_netmask;
+		struct  sockaddr ifru_hwaddr;
+		short	ifru_flags;
+		int	ifru_ivalue;
+		int	ifru_mtu;
+		struct  ifmap ifru_map;
+		char	ifru_slave[IFNAMSIZ];	/* Just fits the size */
+		char	ifru_newname[IFNAMSIZ];
+		void __user *	ifru_data;
+		struct	if_settings ifru_settings;
+	} ifr_ifru;
+};
+#endif /* __UAPI_DEF_IF_IFREQ */
+
+#define ifr_name	ifr_ifrn.ifrn_name	/* interface name 	*/
+#define ifr_hwaddr	ifr_ifru.ifru_hwaddr	/* MAC address 		*/
+#define	ifr_addr	ifr_ifru.ifru_addr	/* address		*/
+#define	ifr_dstaddr	ifr_ifru.ifru_dstaddr	/* other end of p-p lnk	*/
+#define	ifr_broadaddr	ifr_ifru.ifru_broadaddr	/* broadcast address	*/
+#define	ifr_netmask	ifr_ifru.ifru_netmask	/* interface net mask	*/
+#define	ifr_flags	ifr_ifru.ifru_flags	/* flags		*/
+#define	ifr_metric	ifr_ifru.ifru_ivalue	/* metric		*/
+#define	ifr_mtu		ifr_ifru.ifru_mtu	/* mtu			*/
+#define ifr_map		ifr_ifru.ifru_map	/* device map		*/
+#define ifr_slave	ifr_ifru.ifru_slave	/* slave device		*/
+#define	ifr_data	ifr_ifru.ifru_data	/* for use by interface	*/
+#define ifr_ifindex	ifr_ifru.ifru_ivalue	/* interface index	*/
+#define ifr_bandwidth	ifr_ifru.ifru_ivalue    /* link bandwidth	*/
+#define ifr_qlen	ifr_ifru.ifru_ivalue	/* Queue length 	*/
+#define ifr_newname	ifr_ifru.ifru_newname	/* New name		*/
+#define ifr_settings	ifr_ifru.ifru_settings	/* Device/proto settings*/
+
+/*
+ * Structure used in SIOCGIFCONF request.
+ * Used to retrieve interface configuration
+ * for machine (useful for programs which
+ * must know all networks accessible).
+ */
+
+/* for compatibility with glibc net/if.h */
+#if __UAPI_DEF_IF_IFCONF
+struct ifconf  {
+	int	ifc_len;			/* size of buffer	*/
+	union {
+		char __user *ifcu_buf;
+		struct ifreq __user *ifcu_req;
+	} ifc_ifcu;
+};
+#endif /* __UAPI_DEF_IF_IFCONF */
+
+#define	ifc_buf	ifc_ifcu.ifcu_buf		/* buffer address	*/
+#define	ifc_req	ifc_ifcu.ifcu_req		/* array of structures	*/
+
+#endif /* _LINUX_IF_H */
diff --git a/include/linux/libc-compat.h b/include/linux/libc-compat.h
new file mode 100644
index 000000000..8254c937c
--- /dev/null
+++ b/include/linux/libc-compat.h
@@ -0,0 +1,267 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/*
+ * Compatibility interface for userspace libc header coordination:
+ *
+ * Define compatibility macros that are used to control the inclusion or
+ * exclusion of UAPI structures and definitions in coordination with another
+ * userspace C library.
+ *
+ * This header is intended to solve the problem of UAPI definitions that
+ * conflict with userspace definitions. If a UAPI header has such conflicting
+ * definitions then the solution is as follows:
+ *
+ * * Synchronize the UAPI header and the libc headers so either one can be
+ *   used and such that the ABI is preserved. If this is not possible then
+ *   no simple compatibility interface exists (you need to write translating
+ *   wrappers and rename things) and you can't use this interface.
+ *
+ * Then follow this process:
+ *
+ * (a) Include libc-compat.h in the UAPI header.
+ *      e.g. #include <linux/libc-compat.h>
+ *     This include must be as early as possible.
+ *
+ * (b) In libc-compat.h add enough code to detect that the comflicting
+ *     userspace libc header has been included first.
+ *
+ * (c) If the userspace libc header has been included first define a set of
+ *     guard macros of the form __UAPI_DEF_FOO and set their values to 1, else
+ *     set their values to 0.
+ *
+ * (d) Back in the UAPI header with the conflicting definitions, guard the
+ *     definitions with:
+ *     #if __UAPI_DEF_FOO
+ *       ...
+ *     #endif
+ *
+ * This fixes the situation where the linux headers are included *after* the
+ * libc headers. To fix the problem with the inclusion in the other order the
+ * userspace libc headers must be fixed like this:
+ *
+ * * For all definitions that conflict with kernel definitions wrap those
+ *   defines in the following:
+ *   #if !__UAPI_DEF_FOO
+ *     ...
+ *   #endif
+ *
+ * This prevents the redefinition of a construct already defined by the kernel.
+ */
+#ifndef _UAPI_LIBC_COMPAT_H
+#define _UAPI_LIBC_COMPAT_H
+
+/* We have included glibc headers... */
+#if defined(__GLIBC__)
+
+/* Coordinate with glibc net/if.h header. */
+#if defined(_NET_IF_H) && defined(__USE_MISC)
+
+/* GLIBC headers included first so don't define anything
+ * that would already be defined. */
+
+#define __UAPI_DEF_IF_IFCONF 0
+#define __UAPI_DEF_IF_IFMAP 0
+#define __UAPI_DEF_IF_IFNAMSIZ 0
+#define __UAPI_DEF_IF_IFREQ 0
+/* Everything up to IFF_DYNAMIC, matches net/if.h until glibc 2.23 */
+#define __UAPI_DEF_IF_NET_DEVICE_FLAGS 0
+/* For the future if glibc adds IFF_LOWER_UP, IFF_DORMANT and IFF_ECHO */
+#ifndef __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO
+#define __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO 1
+#endif /* __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO */
+
+#else /* _NET_IF_H */
+
+/* Linux headers included first, and we must define everything
+ * we need. The expectation is that glibc will check the
+ * __UAPI_DEF_* defines and adjust appropriately. */
+
+#define __UAPI_DEF_IF_IFCONF 1
+#define __UAPI_DEF_IF_IFMAP 1
+#define __UAPI_DEF_IF_IFNAMSIZ 1
+#define __UAPI_DEF_IF_IFREQ 1
+/* Everything up to IFF_DYNAMIC, matches net/if.h until glibc 2.23 */
+#define __UAPI_DEF_IF_NET_DEVICE_FLAGS 1
+/* For the future if glibc adds IFF_LOWER_UP, IFF_DORMANT and IFF_ECHO */
+#define __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO 1
+
+#endif /* _NET_IF_H */
+
+/* Coordinate with glibc netinet/in.h header. */
+#if defined(_NETINET_IN_H)
+
+/* GLIBC headers included first so don't define anything
+ * that would already be defined. */
+#define __UAPI_DEF_IN_ADDR		0
+#define __UAPI_DEF_IN_IPPROTO		0
+#define __UAPI_DEF_IN_PKTINFO		0
+#define __UAPI_DEF_IP_MREQ		0
+#define __UAPI_DEF_SOCKADDR_IN		0
+#define __UAPI_DEF_IN_CLASS		0
+
+#define __UAPI_DEF_IN6_ADDR		0
+/* The exception is the in6_addr macros which must be defined
+ * if the glibc code didn't define them. This guard matches
+ * the guard in glibc/inet/netinet/in.h which defines the
+ * additional in6_addr macros e.g. s6_addr16, and s6_addr32. */
+#if defined(__USE_MISC) || defined (__USE_GNU)
+#define __UAPI_DEF_IN6_ADDR_ALT		0
+#else
+#define __UAPI_DEF_IN6_ADDR_ALT		1
+#endif
+#define __UAPI_DEF_SOCKADDR_IN6		0
+#define __UAPI_DEF_IPV6_MREQ		0
+#define __UAPI_DEF_IPPROTO_V6		0
+#define __UAPI_DEF_IPV6_OPTIONS		0
+#define __UAPI_DEF_IN6_PKTINFO		0
+#define __UAPI_DEF_IP6_MTUINFO		0
+
+#else
+
+/* Linux headers included first, and we must define everything
+ * we need. The expectation is that glibc will check the
+ * __UAPI_DEF_* defines and adjust appropriately. */
+#define __UAPI_DEF_IN_ADDR		1
+#define __UAPI_DEF_IN_IPPROTO		1
+#define __UAPI_DEF_IN_PKTINFO		1
+#define __UAPI_DEF_IP_MREQ		1
+#define __UAPI_DEF_SOCKADDR_IN		1
+#define __UAPI_DEF_IN_CLASS		1
+
+#define __UAPI_DEF_IN6_ADDR		1
+/* We unconditionally define the in6_addr macros and glibc must
+ * coordinate. */
+#define __UAPI_DEF_IN6_ADDR_ALT		1
+#define __UAPI_DEF_SOCKADDR_IN6		1
+#define __UAPI_DEF_IPV6_MREQ		1
+#define __UAPI_DEF_IPPROTO_V6		1
+#define __UAPI_DEF_IPV6_OPTIONS		1
+#define __UAPI_DEF_IN6_PKTINFO		1
+#define __UAPI_DEF_IP6_MTUINFO		1
+
+#endif /* _NETINET_IN_H */
+
+/* Coordinate with glibc netipx/ipx.h header. */
+#if defined(__NETIPX_IPX_H)
+
+#define __UAPI_DEF_SOCKADDR_IPX			0
+#define __UAPI_DEF_IPX_ROUTE_DEFINITION		0
+#define __UAPI_DEF_IPX_INTERFACE_DEFINITION	0
+#define __UAPI_DEF_IPX_CONFIG_DATA		0
+#define __UAPI_DEF_IPX_ROUTE_DEF		0
+
+#else /* defined(__NETIPX_IPX_H) */
+
+#define __UAPI_DEF_SOCKADDR_IPX			1
+#define __UAPI_DEF_IPX_ROUTE_DEFINITION		1
+#define __UAPI_DEF_IPX_INTERFACE_DEFINITION	1
+#define __UAPI_DEF_IPX_CONFIG_DATA		1
+#define __UAPI_DEF_IPX_ROUTE_DEF		1
+
+#endif /* defined(__NETIPX_IPX_H) */
+
+/* Definitions for xattr.h */
+#if defined(_SYS_XATTR_H)
+#define __UAPI_DEF_XATTR		0
+#else
+#define __UAPI_DEF_XATTR		1
+#endif
+
+/* If we did not see any headers from any supported C libraries,
+ * or we are being included in the kernel, then define everything
+ * that we need. Check for previous __UAPI_* definitions to give
+ * unsupported C libraries a way to opt out of any kernel definition. */
+#else /* !defined(__GLIBC__) */
+
+/* Definitions for if.h */
+#ifndef __UAPI_DEF_IF_IFCONF
+#define __UAPI_DEF_IF_IFCONF 1
+#endif
+#ifndef __UAPI_DEF_IF_IFMAP
+#define __UAPI_DEF_IF_IFMAP 1
+#endif
+#ifndef __UAPI_DEF_IF_IFNAMSIZ
+#define __UAPI_DEF_IF_IFNAMSIZ 1
+#endif
+#ifndef __UAPI_DEF_IF_IFREQ
+#define __UAPI_DEF_IF_IFREQ 1
+#endif
+/* Everything up to IFF_DYNAMIC, matches net/if.h until glibc 2.23 */
+#ifndef __UAPI_DEF_IF_NET_DEVICE_FLAGS
+#define __UAPI_DEF_IF_NET_DEVICE_FLAGS 1
+#endif
+/* For the future if glibc adds IFF_LOWER_UP, IFF_DORMANT and IFF_ECHO */
+#ifndef __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO
+#define __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO 1
+#endif
+
+/* Definitions for in.h */
+#ifndef __UAPI_DEF_IN_ADDR
+#define __UAPI_DEF_IN_ADDR		1
+#endif
+#ifndef __UAPI_DEF_IN_IPPROTO
+#define __UAPI_DEF_IN_IPPROTO		1
+#endif
+#ifndef __UAPI_DEF_IN_PKTINFO
+#define __UAPI_DEF_IN_PKTINFO		1
+#endif
+#ifndef __UAPI_DEF_IP_MREQ
+#define __UAPI_DEF_IP_MREQ		1
+#endif
+#ifndef __UAPI_DEF_SOCKADDR_IN
+#define __UAPI_DEF_SOCKADDR_IN		1
+#endif
+#ifndef __UAPI_DEF_IN_CLASS
+#define __UAPI_DEF_IN_CLASS		1
+#endif
+
+/* Definitions for in6.h */
+#ifndef __UAPI_DEF_IN6_ADDR
+#define __UAPI_DEF_IN6_ADDR		1
+#endif
+#ifndef __UAPI_DEF_IN6_ADDR_ALT
+#define __UAPI_DEF_IN6_ADDR_ALT		1
+#endif
+#ifndef __UAPI_DEF_SOCKADDR_IN6
+#define __UAPI_DEF_SOCKADDR_IN6		1
+#endif
+#ifndef __UAPI_DEF_IPV6_MREQ
+#define __UAPI_DEF_IPV6_MREQ		1
+#endif
+#ifndef __UAPI_DEF_IPPROTO_V6
+#define __UAPI_DEF_IPPROTO_V6		1
+#endif
+#ifndef __UAPI_DEF_IPV6_OPTIONS
+#define __UAPI_DEF_IPV6_OPTIONS		1
+#endif
+#ifndef __UAPI_DEF_IN6_PKTINFO
+#define __UAPI_DEF_IN6_PKTINFO		1
+#endif
+#ifndef __UAPI_DEF_IP6_MTUINFO
+#define __UAPI_DEF_IP6_MTUINFO		1
+#endif
+
+/* Definitions for ipx.h */
+#ifndef __UAPI_DEF_SOCKADDR_IPX
+#define __UAPI_DEF_SOCKADDR_IPX			1
+#endif
+#ifndef __UAPI_DEF_IPX_ROUTE_DEFINITION
+#define __UAPI_DEF_IPX_ROUTE_DEFINITION		1
+#endif
+#ifndef __UAPI_DEF_IPX_INTERFACE_DEFINITION
+#define __UAPI_DEF_IPX_INTERFACE_DEFINITION	1
+#endif
+#ifndef __UAPI_DEF_IPX_CONFIG_DATA
+#define __UAPI_DEF_IPX_CONFIG_DATA		1
+#endif
+#ifndef __UAPI_DEF_IPX_ROUTE_DEF
+#define __UAPI_DEF_IPX_ROUTE_DEF		1
+#endif
+
+/* Definitions for xattr.h */
+#ifndef __UAPI_DEF_XATTR
+#define __UAPI_DEF_XATTR		1
+#endif
+
+#endif /* __GLIBC__ */
+
+#endif /* _UAPI_LIBC_COMPAT_H */
diff --git a/include/subdir.am b/include/subdir.am
index 6f07b6bf1..bcf3ef7b9 100644
--- a/include/subdir.am
+++ b/include/subdir.am
@@ -1,4 +1,7 @@
 noinst_HEADERS += \
+	include/linux/compiler_types.h \
+	include/linux/libc-compat.h \
+	include/linux/if.h \
 	include/linux/if_addr.h \
 	include/linux/if_bridge.h \
 	include/linux/if_link.h \
diff --git a/lib/if.c b/lib/if.c
index bf14baaa5..8f15230f2 100644
--- a/lib/if.c
+++ b/lib/if.c
@@ -6,6 +6,12 @@
 
 #include <zebra.h>
 
+#include <net/if.h>
+
+#ifdef GNU_LINUX
+#include <linux/if.h>
+#endif /* GNU_LINUX */
+
 #include "linklist.h"
 #include "vector.h"
 #include "lib_errors.h"
@@ -668,21 +674,26 @@ int if_is_running(const struct interface *ifp)
    if ptm checking is enabled, then ptm check has passed */
 int if_is_operative(const struct interface *ifp)
 {
-	return ((ifp->flags & IFF_UP)
-		&& (((ifp->flags & IFF_RUNNING)
-		     && (ifp->ptm_status || !ifp->ptm_enable))
-		    || !CHECK_FLAG(ifp->status,
-				   ZEBRA_INTERFACE_LINKDETECTION)));
+	return ((ifp->flags & IFF_UP) &&
+		(((ifp->flags & IFF_RUNNING)
+#ifdef IFF_LOWER_UP
+		  && (ifp->flags & IFF_LOWER_UP)
+#endif /* IFF_LOWER_UP */
+		  && (ifp->ptm_status || !ifp->ptm_enable)) ||
+		 !CHECK_FLAG(ifp->status, ZEBRA_INTERFACE_LINKDETECTION)));
 }
 
 /* Is the interface operative, eg. either UP & RUNNING
    or UP & !ZEBRA_INTERFACE_LINK_DETECTION, without PTM check */
 int if_is_no_ptm_operative(const struct interface *ifp)
 {
-	return ((ifp->flags & IFF_UP)
-		&& ((ifp->flags & IFF_RUNNING)
-		    || !CHECK_FLAG(ifp->status,
-				   ZEBRA_INTERFACE_LINKDETECTION)));
+	return ((ifp->flags & IFF_UP) &&
+		(((ifp->flags & IFF_RUNNING)
+#ifdef IFF_LOWER_UP
+		  && (ifp->flags & IFF_LOWER_UP)
+#endif /* IFF_LOWER_UP */
+			  ) ||
+		 !CHECK_FLAG(ifp->status, ZEBRA_INTERFACE_LINKDETECTION)));
 }
 
 /* Is this loopback interface ? */
@@ -744,6 +755,9 @@ const char *if_flag_dump(unsigned long flag)
 
 	strlcpy(logbuf, "<", BUFSIZ);
 	IFF_OUT_LOG(IFF_UP, "UP");
+#ifdef IFF_LOWER_UP
+	IFF_OUT_LOG(IFF_LOWER_UP, "LOWER_UP");
+#endif /* IFF_LOWER_UP */
 	IFF_OUT_LOG(IFF_BROADCAST, "BROADCAST");
 	IFF_OUT_LOG(IFF_DEBUG, "DEBUG");
 	IFF_OUT_LOG(IFF_LOOPBACK, "LOOPBACK");
diff --git a/tests/topotests/all_protocol_startup/r1/show_ip_ospf_interface.ref b/tests/topotests/all_protocol_startup/r1/show_ip_ospf_interface.ref
index 7e28f04e1..f52b51d9d 100644
--- a/tests/topotests/all_protocol_startup/r1/show_ip_ospf_interface.ref
+++ b/tests/topotests/all_protocol_startup/r1/show_ip_ospf_interface.ref
@@ -1,5 +1,5 @@
 r1-eth0 is up
-  ifindex X, MTU 1500 bytes, BW XX Mbit <UP,BROADCAST,RUNNING,MULTICAST>
+  ifindex X, MTU 1500 bytes, BW XX Mbit <UP,LOWER_UP,BROADCAST,RUNNING,MULTICAST>
   Internet Address 192.168.0.1/24, Broadcast 192.168.0.255, Area 0.0.0.0
   MTU mismatch detection: enabled
   Router ID 192.168.0.1, Network Type BROADCAST, Cost: 10
@@ -12,7 +12,7 @@ r1-eth0 is up
   Neighbor Count is 0, Adjacent neighbor count is 0
   Graceful Restart hello delay: 10s
 r1-eth3 is up
-  ifindex X, MTU 1500 bytes, BW XX Mbit <UP,BROADCAST,RUNNING,MULTICAST>
+  ifindex X, MTU 1500 bytes, BW XX Mbit <UP,LOWER_UP,BROADCAST,RUNNING,MULTICAST>
   Internet Address 192.168.3.1/26, Broadcast 192.168.3.63, Area 0.0.0.0
   MTU mismatch detection: enabled
   Router ID 192.168.0.1, Network Type BROADCAST, Cost: 10
diff --git a/tests/topotests/nhrp_topo/test_nhrp_topo.py b/tests/topotests/nhrp_topo/test_nhrp_topo.py
index 26115de2b..284c58a8e 100644
--- a/tests/topotests/nhrp_topo/test_nhrp_topo.py
+++ b/tests/topotests/nhrp_topo/test_nhrp_topo.py
@@ -189,7 +189,7 @@ def test_protocols_convergence():
 
         expected = {
             "{}-gre0".format(rname): {
-                "flags": "<UP,RUNNING>",
+                "flags": "<UP,LOWER_UP,RUNNING>",
             }
         }
         test_func = partial(
diff --git a/tests/topotests/ospf_basic_functionality/test_ospf_single_area.py b/tests/topotests/ospf_basic_functionality/test_ospf_single_area.py
index 172f79d45..59afc7a8a 100644
--- a/tests/topotests/ospf_basic_functionality/test_ospf_single_area.py
+++ b/tests/topotests/ospf_basic_functionality/test_ospf_single_area.py
@@ -607,7 +607,7 @@ def test_ospf_show_p1(request):
                 "r0": {
                     "ospf": {
                         "ifUp": True,
-                        "ifFlags": "<UP,BROADCAST,RUNNING,MULTICAST>",
+                        "ifFlags": "<UP,LOWER_UP,BROADCAST,RUNNING,MULTICAST>",
                         "ospfEnabled": True,
                         "ipAddressPrefixlen": 24,
                         "ospfIfType": "Broadcast",
diff --git a/zebra/fpm_listener.c b/zebra/fpm_listener.c
index 63977633a..7d84c706d 100644
--- a/zebra/fpm_listener.c
+++ b/zebra/fpm_listener.c
@@ -417,7 +417,7 @@ static int netlink_msg_ctx_add_nh(struct netlink_msg_ctx *ctx, int if_index,
 static int parse_multipath_attr(struct netlink_msg_ctx *ctx,
 				struct rtattr *mpath_rtattr)
 {
-	size_t len;
+	int len;
 	struct rtnexthop *rtnh;
 	struct rtattr *rtattrs[RTA_MAX + 1];
 	struct rtattr *tb[RTA_MAX + 1];