[apple/xnu.git] / bsd / net / net_osdep.h

/*
 * Copyright (c) 2000-2010 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 * 
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */
/*
 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the project nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */
/*
 * glue for kernel code programming differences.
 */

/*
 * OS dependencies:
 *
 * - whether the IPv4 input routine convert the byte order of some fileds
 *   of the IP header (x: convert to the host byte order, s: strip the header
 *   length for possible reassembly)
 *          ip_len ip_id ip_off
 * bsdi3:       xs     x      x
 * bsdi4:       xs            x
 * FreeBSD:     xs            x
 * NetBSD:       x            x
 * OpenBSD:     xs     x      x
 *
 * - ifa_ifwithaf()
 *   bsdi[34], netbsd, and openbsd define it in sys/net/if.c
 *   freebsd (all versions) does not have it.
 *  
 * - struct rt_addrinfo
 *   bsdi4, netbsd 1.5R and beyond: rti_addrs, rti_info[], rti_flags, rti_ifa,
 *	rti_ifp, and rti_rtm.
 *   others: rti_addrs and rti_info[] only.
 *
 * - ifa->ifa_rtrequest
 *   bsdi4, netbsd 1.5R and beyond: rt_addrinfo *
 *   others: sockaddr * (note that sys/net/route.c:rtrequest() has an unsafe
 *	typecast code, from 4.3BSD-reno)
 *
 * - side effects of rtrequest{,1}(RTM_DELETE)
 *	BSDI[34]: delete all cloned routes underneath the route.
 *	FreeBSD[234]: delete all protocol-cloned routes underneath the route.
 *		      note that cloned routes from an interface direct route
 *		      still remain.
 *	NetBSD: 1.5 have no side effects.  KAME/netbsd15, and post-1.5R, have
 *		the same effects as of BSDI.
 *	OpenBSD: have no side effects.  KAME/openbsd has the same effects as
 *		of BSDI (the change is not merged - yet).
 *
 * - privileged process
 *	NetBSD, FreeBSD 3
 *		struct proc *p;
 *		if (p && !suser(p->p_ucred, &p->p_acflag))
 *			privileged;
 *	FreeBSD 4
 *		struct proc *p;
 *		if (p && !suser(p))
 *			privileged;
 *	OpenBSD, BSDI [34], FreeBSD 2
 *		struct socket *so;
 *		if (so->so_state & SS_PRIV)
 *			privileged;
 * - foo_control
 *	NetBSD, FreeBSD 3
 *		needs to give struct proc * as argument
 *	OpenBSD, BSDI [34], FreeBSD 2
 *		do not need struct proc *
 *
 * - bpf:
 *	OpenBSD, NetBSD 1.5, BSDI [34]
 *		need caddr_t * (= if_bpf **) and struct ifnet *
 *	FreeBSD 2, FreeBSD 3, NetBSD post-1.5N
 *		need only struct ifnet * as argument
 *
 * - struct ifnet
 *			use queue.h?	member names	if name
 *			---		---		---
 *	FreeBSD 2	no		old standard	if_name+unit
 *	FreeBSD 3	yes		strange		if_name+unit
 *	OpenBSD		yes		standard	if_xname
 *	NetBSD		yes		standard	if_xname
 *	BSDI [34]	no		old standard	if_name+unit
 *
 * - usrreq
 *	NetBSD, OpenBSD, BSDI [34], FreeBSD 2
 *		single function with PRU_xx, arguments are mbuf
 *	FreeBSD 3
 *		separates functions, non-mbuf arguments
 *
 * - {set,get}sockopt
 *	NetBSD, OpenBSD, BSDI [34], FreeBSD 2
 *		manipulation based on mbuf
 *	FreeBSD 3
 *		non-mbuf manipulation using sooptcopy{in,out}()
 *
 * - timeout() and untimeout()
 *	NetBSD 1.4.x, OpenBSD, BSDI [34], FreeBSD 2
 *		timeout() is a void function
 *	FreeBSD 3
 *		timeout() is non-void, must keep returned value for untimeout()
 *		callout_xx is also available (sys/callout.h)
 *	NetBSD 1.5
 *		timeout() is obsoleted, use callout_xx (sys/callout.h)
 *	OpenBSD 2.8
 *		timeout_{add,set,del} is encouraged (sys/timeout.h)
 *
 * - sysctl
 *	NetBSD, OpenBSD
 *		foo_sysctl()
 *	BSDI [34]
 *		foo_sysctl() but with different style.  sysctl_int_arr() takes
 *		care of most of the cases.
 *	FreeBSD
 *		linker hack.  however, there are freebsd version differences
 *		(how wonderful!).
 *		on FreeBSD[23] function arg #define includes paren.
 *			int foo SYSCTL_HANDLER_ARGS;
 *		on FreeBSD4, function arg #define does not include paren.
 *			int foo(SYSCTL_HANDLER_ARGS);
 *		on some versions, forward reference to the tree is okay.
 *		on some versions, you need SYSCTL_DECL().  you need things
 *		like this.
 *			#ifdef SYSCTL_DECL
 *			SYSCTL_DECL(net_inet_ip6);
 *			#endif
 *		it is hard to share functions between freebsd and non-freebsd.
 *
 * - if_ioctl
 *	NetBSD, FreeBSD 3, BSDI [34]
 *		2nd argument is u_long cmd
 *	FreeBSD 2
 *		2nd argument is int cmd
 *
 * - if attach routines
 *	NetBSD
 *		void xxattach(int);
 *	FreeBSD 2, FreeBSD 3
 *		void xxattach(void *);
 *		PSEUDO_SET(xxattach, if_xx);
 *
 * - ovbcopy()
 *	in NetBSD 1.4 or later, ovbcopy() is not supplied in the kernel.
 *	bcopy() is safe against overwrites.
 *
 * - splnet()
 *	NetBSD 1.4 or later requires splsoftnet().
 *	other operating systems use splnet().
 *
 * - dtom()
 *	NEVER USE IT!
 *
 * - struct ifnet for loopback interface
 *	BSDI3: struct ifnet loif;
 *	BSDI4: struct ifnet *loifp;
 *	NetBSD, OpenBSD 2.8, FreeBSD2: struct ifnet loif[NLOOP];
 *	OpenBSD 2.9: struct ifnet *lo0ifp;
 *
 *	odd thing is that many of them refers loif as ifnet *loif,
 *	not loif[NLOOP], from outside of if_loop.c.
 *
 * - number of bpf pseudo devices
 *	others: bpfilter.h, NBPFILTER
 *	FreeBSD4: bpf.h, NBPF
 *	solution:
 *		#if defined(__FreeBSD__) && __FreeBSD__ >= 4
 *		#include "bpf.h"
 *		#define NBPFILTER	NBPF
 *		#else
 *		#include "bpfilter.h"
 *		#endif
 *
 * - protosw for IPv4 (sys/netinet)
 *	FreeBSD4: struct ipprotosw in netinet/ipprotosw.h
 *	others: struct protosw in sys/protosw.h
 *
 * - protosw in general.
 *	NetBSD 1.5 has extra member for ipfilter (netbsd-current dropped
 *	it so it will go away in 1.6).
 *	NetBSD 1.5 requires PR_LISTEN flag bit with protocols that permit
 *	listen/accept (like tcp).
 *
 * - header files with defopt (opt_xx.h)
 *	FreeBSD3: opt_{inet,ipsec,ip6fw,altq}.h
 *	FreeBSD4: opt_{inet,inet6,ipsec,ip6fw,altq}.h
 *	NetBSD: opt_{inet,ipsec,altq}.h
 *	others: does not use defopt
 *
 * - (m->m_flags & M_EXT) != 0 does *not* mean that the max data length of
 *   the mbuf == MCLBYTES.
 *
 * - sys/kern/uipc_mbuf.c:m_dup()
 *	freebsd[34]: copies the whole mbuf chain.
 *	netbsd: similar arg with m_copym().
 *	others: no m_dup().
 *
 * - ifa_refcnt (struct ifaddr) management (IFAREF/IFAFREE).
 *	NetBSD 1.5: always use IFAREF whenever reference gets added.
 *		always use IFAFREE whenever reference gets freed.
 *		IFAFREE frees ifaddr when ifa_refcnt reaches 0.
 *	Darwin: always use IFA_ADDREF whenever reference gets added.
 *		always use IFA_REMREF whenever reference gets freed.
 *		IFA_ADDREF and IFA_REMREF are responsible for determining
 *		when to free.
 *	others: do not increase refcnt for ifp->if_addrlist and in_ifaddr.
 *		use IFAFREE once when ifaddr is disconnected from
 *		ifp->if_addrlist and in_ifaddr.  IFAFREE frees ifaddr when
 *		ifa_refcnt goes negative.
 */

#ifndef __NET_NET_OSDEP_H_DEFINED_
#define __NET_NET_OSDEP_H_DEFINED_
#include <sys/appleapiopts.h>
#ifdef KERNEL_PRIVATE

struct ifnet;

#define HAVE_OLD_BPF

#define ifa_list	ifa_link
#define if_addrlist	if_addrhead
#define if_list		if_link

#define WITH_CONVERT_AND_STRIP_IP_LEN

#if 1				/* at this moment, all OSes do this */
#define WITH_CONVERT_IP_OFF
#endif

#endif /* KERNEL_PRIVATE */
#endif /*__NET_NET_OSDEP_H_DEFINED_ */
Commit	Line	Data
1c79356b	1	/*
6d2010ae	2	* Copyright (c) 2000-2010 Apple Inc. All rights reserved.
5d5c5d0d	3	*
2d21ac55	4	* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
1c79356b	5	*
2d21ac55 A	6	* This file contains Original Code and/or Modifications of Original Code
	7	* as defined in and that are subject to the Apple Public Source License
	8	* Version 2.0 (the 'License'). You may not use this file except in
	9	* compliance with the License. The rights granted to you under the License
	10	* may not be used to create, or enable the creation or redistribution of,
	11	* unlawful or unlicensed copies of an Apple operating system, or to
	12	* circumvent, violate, or enable the circumvention or violation of, any
	13	* terms of an Apple operating system software license agreement.
8f6c56a5	14	*
2d21ac55 A	15	* Please obtain a copy of the License at
	16	* http://www.opensource.apple.com/apsl/ and read it before using this file.
	17	*
	18	* The Original Code and all software distributed under the License are
	19	* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
8f6c56a5 A	20	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
8f6c56a5 A	21	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
2d21ac55 A	22	* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
	23	* Please see the License for the specific language governing rights and
	24	* limitations under the License.
8f6c56a5	25	*
2d21ac55	26	* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
1c79356b A	27	*/
	28	/*
	29	* Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
	30	* All rights reserved.
9bccf70c	31	*
1c79356b A	32	* Redistribution and use in source and binary forms, with or without
	33	* modification, are permitted provided that the following conditions
	34	* are met:
	35	* 1. Redistributions of source code must retain the above copyright
	36	* notice, this list of conditions and the following disclaimer.
	37	* 2. Redistributions in binary form must reproduce the above copyright
	38	* notice, this list of conditions and the following disclaimer in the
	39	* documentation and/or other materials provided with the distribution.
	40	* 3. Neither the name of the project nor the names of its contributors
	41	* may be used to endorse or promote products derived from this software
	42	* without specific prior written permission.
9bccf70c	43	*
1c79356b A	44	* THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
	45	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	46	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	47	* ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
	48	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	49	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	50	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	51	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	52	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	53	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	54	* SUCH DAMAGE.
	55	*/
	56	/*
	57	* glue for kernel code programming differences.
	58	*/
	59
	60	/*
	61	* OS dependencies:
	62	*
9bccf70c A	63	* - whether the IPv4 input routine convert the byte order of some fileds
	64	* of the IP header (x: convert to the host byte order, s: strip the header
	65	* length for possible reassembly)
	66	* ip_len ip_id ip_off
	67	* bsdi3: xs x x
	68	* bsdi4: xs x
	69	* FreeBSD: xs x
	70	* NetBSD: x x
	71	* OpenBSD: xs x x
	72	*
	73	* - ifa_ifwithaf()
	74	* bsdi[34], netbsd, and openbsd define it in sys/net/if.c
	75	* freebsd (all versions) does not have it.
	76	*
	77	* - struct rt_addrinfo
	78	* bsdi4, netbsd 1.5R and beyond: rti_addrs, rti_info[], rti_flags, rti_ifa,
	79	* rti_ifp, and rti_rtm.
	80	* others: rti_addrs and rti_info[] only.
	81	*
	82	* - ifa->ifa_rtrequest
	83	* bsdi4, netbsd 1.5R and beyond: rt_addrinfo *
	84	* others: sockaddr * (note that sys/net/route.c:rtrequest() has an unsafe
	85	* typecast code, from 4.3BSD-reno)
	86	*
	87	* - side effects of rtrequest{,1}(RTM_DELETE)
	88	* BSDI[34]: delete all cloned routes underneath the route.
	89	* FreeBSD[234]: delete all protocol-cloned routes underneath the route.
	90	* note that cloned routes from an interface direct route
	91	* still remain.
	92	* NetBSD: 1.5 have no side effects. KAME/netbsd15, and post-1.5R, have
	93	* the same effects as of BSDI.
	94	* OpenBSD: have no side effects. KAME/openbsd has the same effects as
	95	* of BSDI (the change is not merged - yet).
	96	*
1c79356b A	97	* - privileged process
	98	* NetBSD, FreeBSD 3
	99	* struct proc *p;
	100	* if (p && !suser(p->p_ucred, &p->p_acflag))
	101	* privileged;
9bccf70c A	102	* FreeBSD 4
	103	* struct proc *p;
	104	* if (p && !suser(p))
	105	* privileged;
1c79356b A	106	* OpenBSD, BSDI [34], FreeBSD 2
	107	* struct socket *so;
	108	* if (so->so_state & SS_PRIV)
	109	* privileged;
	110	* - foo_control
	111	* NetBSD, FreeBSD 3
	112	* needs to give struct proc * as argument
	113	* OpenBSD, BSDI [34], FreeBSD 2
	114	* do not need struct proc *
9bccf70c	115	*
1c79356b	116	* - bpf:
9bccf70c	117	* OpenBSD, NetBSD 1.5, BSDI [34]
1c79356b	118	* need caddr_t * (= if_bpf *) and struct ifnet
9bccf70c	119	* FreeBSD 2, FreeBSD 3, NetBSD post-1.5N
1c79356b	120	* need only struct ifnet * as argument
9bccf70c	121	*
1c79356b A	122	* - struct ifnet
	123	* use queue.h? member names if name
	124	* --- --- ---
	125	* FreeBSD 2 no old standard if_name+unit
	126	* FreeBSD 3 yes strange if_name+unit
	127	* OpenBSD yes standard if_xname
	128	* NetBSD yes standard if_xname
	129	* BSDI [34] no old standard if_name+unit
9bccf70c	130	*
1c79356b A	131	* - usrreq
1c79356b A	132	* NetBSD, OpenBSD, BSDI [34], FreeBSD 2
9bccf70c	133	* single function with PRU_xx, arguments are mbuf
1c79356b A	134	* FreeBSD 3
1c79356b A	135	* separates functions, non-mbuf arguments
9bccf70c	136	*
1c79356b A	137	* - {set,get}sockopt
	138	* NetBSD, OpenBSD, BSDI [34], FreeBSD 2
	139	* manipulation based on mbuf
	140	* FreeBSD 3
	141	* non-mbuf manipulation using sooptcopy{in,out}()
9bccf70c	142	*
1c79356b	143	* - timeout() and untimeout()
9bccf70c	144	* NetBSD 1.4.x, OpenBSD, BSDI [34], FreeBSD 2
1c79356b A	145	* timeout() is a void function
1c79356b A	146	* FreeBSD 3
9bccf70c A	147	* timeout() is non-void, must keep returned value for untimeout()
	148	* callout_xx is also available (sys/callout.h)
	149	* NetBSD 1.5
	150	* timeout() is obsoleted, use callout_xx (sys/callout.h)
	151	* OpenBSD 2.8
	152	* timeout_{add,set,del} is encouraged (sys/timeout.h)
	153	*
1c79356b A	154	* - sysctl
	155	* NetBSD, OpenBSD
	156	* foo_sysctl()
	157	* BSDI [34]
9bccf70c A	158	* foo_sysctl() but with different style. sysctl_int_arr() takes
	159	* care of most of the cases.
	160	* FreeBSD
	161	* linker hack. however, there are freebsd version differences
	162	* (how wonderful!).
	163	* on FreeBSD[23] function arg #define includes paren.
	164	* int foo SYSCTL_HANDLER_ARGS;
	165	* on FreeBSD4, function arg #define does not include paren.
	166	* int foo(SYSCTL_HANDLER_ARGS);
	167	* on some versions, forward reference to the tree is okay.
	168	* on some versions, you need SYSCTL_DECL(). you need things
	169	* like this.
	170	* #ifdef SYSCTL_DECL
	171	* SYSCTL_DECL(net_inet_ip6);
	172	* #endif
	173	* it is hard to share functions between freebsd and non-freebsd.
1c79356b A	174	*
	175	* - if_ioctl
	176	* NetBSD, FreeBSD 3, BSDI [34]
	177	* 2nd argument is u_long cmd
	178	* FreeBSD 2
	179	* 2nd argument is int cmd
9bccf70c	180	*
1c79356b A	181	* - if attach routines
	182	* NetBSD
	183	* void xxattach(int);
	184	* FreeBSD 2, FreeBSD 3
	185	* void xxattach(void *);
	186	* PSEUDO_SET(xxattach, if_xx);
	187	*
	188	* - ovbcopy()
	189	* in NetBSD 1.4 or later, ovbcopy() is not supplied in the kernel.
	190	* bcopy() is safe against overwrites.
9bccf70c	191	*
1c79356b A	192	* - splnet()
	193	* NetBSD 1.4 or later requires splsoftnet().
	194	* other operating systems use splnet().
	195	*
	196	* - dtom()
	197	* NEVER USE IT!
	198	*
	199	* - struct ifnet for loopback interface
	200	* BSDI3: struct ifnet loif;
	201	* BSDI4: struct ifnet *loifp;
9bccf70c A	202	* NetBSD, OpenBSD 2.8, FreeBSD2: struct ifnet loif[NLOOP];
9bccf70c A	203	* OpenBSD 2.9: struct ifnet *lo0ifp;
1c79356b A	204	*
	205	* odd thing is that many of them refers loif as ifnet *loif,
	206	* not loif[NLOOP], from outside of if_loop.c.
9bccf70c A	207	*
	208	* - number of bpf pseudo devices
	209	* others: bpfilter.h, NBPFILTER
	210	* FreeBSD4: bpf.h, NBPF
	211	* solution:
	212	* #if defined(__FreeBSD__) && __FreeBSD__ >= 4
	213	* #include "bpf.h"
	214	* #define NBPFILTER NBPF
	215	* #else
	216	* #include "bpfilter.h"
	217	* #endif
	218	*
	219	* - protosw for IPv4 (sys/netinet)
	220	* FreeBSD4: struct ipprotosw in netinet/ipprotosw.h
	221	* others: struct protosw in sys/protosw.h
	222	*
	223	* - protosw in general.
	224	* NetBSD 1.5 has extra member for ipfilter (netbsd-current dropped
	225	* it so it will go away in 1.6).
	226	* NetBSD 1.5 requires PR_LISTEN flag bit with protocols that permit
	227	* listen/accept (like tcp).
	228	*
	229	* - header files with defopt (opt_xx.h)
	230	* FreeBSD3: opt_{inet,ipsec,ip6fw,altq}.h
	231	* FreeBSD4: opt_{inet,inet6,ipsec,ip6fw,altq}.h
	232	* NetBSD: opt_{inet,ipsec,altq}.h
	233	* others: does not use defopt
	234	*
	235	* - (m->m_flags & M_EXT) != 0 does not mean that the max data length of
	236	* the mbuf == MCLBYTES.
	237	*
	238	* - sys/kern/uipc_mbuf.c:m_dup()
	239	* freebsd[34]: copies the whole mbuf chain.
	240	* netbsd: similar arg with m_copym().
	241	* others: no m_dup().
	242	*
	243	* - ifa_refcnt (struct ifaddr) management (IFAREF/IFAFREE).
	244	* NetBSD 1.5: always use IFAREF whenever reference gets added.
	245	* always use IFAFREE whenever reference gets freed.
	246	* IFAFREE frees ifaddr when ifa_refcnt reaches 0.
6d2010ae A	247	* Darwin: always use IFA_ADDREF whenever reference gets added.
	248	* always use IFA_REMREF whenever reference gets freed.
	249	* IFA_ADDREF and IFA_REMREF are responsible for determining
	250	* when to free.
9bccf70c A	251	* others: do not increase refcnt for ifp->if_addrlist and in_ifaddr.
	252	* use IFAFREE once when ifaddr is disconnected from
	253	* ifp->if_addrlist and in_ifaddr. IFAFREE frees ifaddr when
	254	* ifa_refcnt goes negative.
1c79356b A	255	*/
	256
	257	#ifndef __NET_NET_OSDEP_H_DEFINED_
	258	#define __NET_NET_OSDEP_H_DEFINED_
9bccf70c	259	#include <sys/appleapiopts.h>
91447636	260	#ifdef KERNEL_PRIVATE
1c79356b	261
1c79356b	262	struct ifnet;
1c79356b	263
1c79356b	264	#define HAVE_OLD_BPF
1c79356b	265
1c79356b A	266	#define ifa_list ifa_link
	267	#define if_addrlist if_addrhead
	268	#define if_list if_link
1c79356b	269
9bccf70c A	270	#define WITH_CONVERT_AND_STRIP_IP_LEN
	271
	272	#if 1 /* at this moment, all OSes do this */
	273	#define WITH_CONVERT_IP_OFF
1c79356b A	274	#endif
1c79356b A	275
91447636	276	#endif /* KERNEL_PRIVATE */
1c79356b	277	#endif /__NET_NET_OSDEP_H_DEFINED_ /