xref: /netbsd-src/sys/netinet/in.h (revision 23c8222edbfb0f0932d88a8351d3a0cf817dfb9e)
1 /*	$NetBSD: in.h,v 1.68 2004/09/04 23:30:07 manu Exp $	*/
2 
3 /*
4  * Copyright (c) 1982, 1986, 1990, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  *
31  *	@(#)in.h	8.3 (Berkeley) 1/3/94
32  */
33 
34 /*
35  * Constants and structures defined by the internet system,
36  * Per RFC 790, September 1981, and numerous additions.
37  */
38 
39 #ifndef _NETINET_IN_H_
40 #define	_NETINET_IN_H_
41 
42 #include <machine/int_types.h>
43 
44 #ifndef uint8_t
45 typedef __uint8_t	uint8_t;
46 #define	uint8_t		__uint8_t
47 #endif
48 
49 #ifndef uint32_t
50 typedef __uint32_t	uint32_t;
51 #define	uint32_t	__uint32_t
52 #endif
53 
54 #include <sys/ansi.h>
55 
56 #ifndef in_addr_t
57 typedef __in_addr_t	in_addr_t;
58 #define	in_addr_t	__in_addr_t
59 #endif
60 
61 #ifndef in_port_t
62 typedef __in_port_t	in_port_t;
63 #define	in_port_t	__in_port_t
64 #endif
65 
66 #ifndef sa_family_t
67 typedef __sa_family_t	sa_family_t;
68 #define	sa_family_t	__sa_family_t
69 #endif
70 
71 /*
72  * Protocols
73  */
74 #define	IPPROTO_IP		0		/* dummy for IP */
75 #define	IPPROTO_HOPOPTS		0		/* IP6 hop-by-hop options */
76 #define	IPPROTO_ICMP		1		/* control message protocol */
77 #define	IPPROTO_IGMP		2		/* group mgmt protocol */
78 #define	IPPROTO_GGP		3		/* gateway^2 (deprecated) */
79 #define	IPPROTO_IPV4		4 		/* IP header */
80 #define	IPPROTO_IPIP		4		/* IP inside IP */
81 #define	IPPROTO_TCP		6		/* tcp */
82 #define	IPPROTO_EGP		8		/* exterior gateway protocol */
83 #define	IPPROTO_PUP		12		/* pup */
84 #define	IPPROTO_UDP		17		/* user datagram protocol */
85 #define	IPPROTO_IDP		22		/* xns idp */
86 #define	IPPROTO_TP		29 		/* tp-4 w/ class negotiation */
87 #define	IPPROTO_IPV6		41		/* IP6 header */
88 #define	IPPROTO_ROUTING		43		/* IP6 routing header */
89 #define	IPPROTO_FRAGMENT	44		/* IP6 fragmentation header */
90 #define	IPPROTO_RSVP		46		/* resource reservation */
91 #define	IPPROTO_GRE		47		/* GRE encaps RFC 1701 */
92 #define	IPPROTO_ESP		50 		/* encap. security payload */
93 #define	IPPROTO_AH		51 		/* authentication header */
94 #define	IPPROTO_MOBILE		55		/* IP Mobility RFC 2004 */
95 #define	IPPROTO_IPV6_ICMP	58		/* IPv6 ICMP */
96 #define	IPPROTO_ICMPV6		58		/* ICMP6 */
97 #define	IPPROTO_NONE		59		/* IP6 no next header */
98 #define	IPPROTO_DSTOPTS		60		/* IP6 destination option */
99 #define	IPPROTO_EON		80		/* ISO cnlp */
100 #define	IPPROTO_ENCAP		98		/* encapsulation header */
101 #define	IPPROTO_PIM		103		/* Protocol indep. multicast */
102 #define	IPPROTO_IPCOMP		108		/* IP Payload Comp. Protocol */
103 #define	IPPROTO_VRRP		112		/* VRRP RFC 2338 */
104 
105 #define	IPPROTO_RAW		255		/* raw IP packet */
106 #define	IPPROTO_MAX		256
107 
108 /* last return value of *_input(), meaning "all job for this pkt is done".  */
109 #define	IPPROTO_DONE		257
110 
111 /* sysctl placeholder for (FAST_)IPSEC */
112 #define CTL_IPPROTO_IPSEC	258
113 
114 
115 /*
116  * Local port number conventions:
117  *
118  * Ports < IPPORT_RESERVED are reserved for privileged processes (e.g. root),
119  * unless a kernel is compiled with IPNOPRIVPORTS defined.
120  *
121  * When a user does a bind(2) or connect(2) with a port number of zero,
122  * a non-conflicting local port address is chosen.
123  *
124  * The default range is IPPORT_ANONMIN to IPPORT_ANONMAX, although
125  * that is settable by sysctl(3); net.inet.ip.anonportmin and
126  * net.inet.ip.anonportmax respectively.
127  *
128  * A user may set the IPPROTO_IP option IP_PORTRANGE to change this
129  * default assignment range.
130  *
131  * The value IP_PORTRANGE_DEFAULT causes the default behavior.
132  *
133  * The value IP_PORTRANGE_HIGH is the same as IP_PORTRANGE_DEFAULT,
134  * and exists only for FreeBSD compatibility purposes.
135  *
136  * The value IP_PORTRANGE_LOW changes the range to the "low" are
137  * that is (by convention) restricted to privileged processes.
138  * This convention is based on "vouchsafe" principles only.
139  * It is only secure if you trust the remote host to restrict these ports.
140  * The range is IPPORT_RESERVEDMIN to IPPORT_RESERVEDMAX.
141  */
142 
143 #define	IPPORT_RESERVED		1024
144 #define	IPPORT_ANONMIN		49152
145 #define	IPPORT_ANONMAX		65535
146 #define	IPPORT_RESERVEDMIN	600
147 #define	IPPORT_RESERVEDMAX	(IPPORT_RESERVED-1)
148 
149 /*
150  * Internet address (a structure for historical reasons)
151  */
152 struct in_addr {
153 	in_addr_t s_addr;
154 } __attribute__((__packed__));
155 
156 /*
157  * Definitions of bits in internet address integers.
158  * On subnets, the decomposition of addresses to host and net parts
159  * is done according to subnet mask, not the masks here.
160  *
161  * By byte-swapping the constants, we avoid ever having to byte-swap IP
162  * addresses inside the kernel.  Unfortunately, user-level programs rely
163  * on these macros not doing byte-swapping.
164  */
165 #ifdef _KERNEL
166 #define	__IPADDR(x)	((uint32_t) htonl((uint32_t)(x)))
167 #else
168 #define	__IPADDR(x)	((uint32_t)(x))
169 #endif
170 
171 #define	IN_CLASSA(i)		(((uint32_t)(i) & __IPADDR(0x80000000)) == \
172 				 __IPADDR(0x00000000))
173 #define	IN_CLASSA_NET		__IPADDR(0xff000000)
174 #define	IN_CLASSA_NSHIFT	24
175 #define	IN_CLASSA_HOST		__IPADDR(0x00ffffff)
176 #define	IN_CLASSA_MAX		128
177 
178 #define	IN_CLASSB(i)		(((uint32_t)(i) & __IPADDR(0xc0000000)) == \
179 				 __IPADDR(0x80000000))
180 #define	IN_CLASSB_NET		__IPADDR(0xffff0000)
181 #define	IN_CLASSB_NSHIFT	16
182 #define	IN_CLASSB_HOST		__IPADDR(0x0000ffff)
183 #define	IN_CLASSB_MAX		65536
184 
185 #define	IN_CLASSC(i)		(((uint32_t)(i) & __IPADDR(0xe0000000)) == \
186 				 __IPADDR(0xc0000000))
187 #define	IN_CLASSC_NET		__IPADDR(0xffffff00)
188 #define	IN_CLASSC_NSHIFT	8
189 #define	IN_CLASSC_HOST		__IPADDR(0x000000ff)
190 
191 #define	IN_CLASSD(i)		(((uint32_t)(i) & __IPADDR(0xf0000000)) == \
192 				 __IPADDR(0xe0000000))
193 /* These ones aren't really net and host fields, but routing needn't know. */
194 #define	IN_CLASSD_NET		__IPADDR(0xf0000000)
195 #define	IN_CLASSD_NSHIFT	28
196 #define	IN_CLASSD_HOST		__IPADDR(0x0fffffff)
197 #define	IN_MULTICAST(i)		IN_CLASSD(i)
198 
199 #define	IN_EXPERIMENTAL(i)	(((uint32_t)(i) & __IPADDR(0xf0000000)) == \
200 				 __IPADDR(0xf0000000))
201 #define	IN_BADCLASS(i)		(((uint32_t)(i) & __IPADDR(0xf0000000)) == \
202 				 __IPADDR(0xf0000000))
203 
204 #define	IN_LOCAL_GROUP(i)	(((uint32_t)(i) & __IPADDR(0xffffff00)) == \
205 				 __IPADDR(0xe0000000))
206 
207 #define	INADDR_ANY		__IPADDR(0x00000000)
208 #define	INADDR_LOOPBACK		__IPADDR(0x7f000001)
209 #define	INADDR_BROADCAST	__IPADDR(0xffffffff)	/* must be masked */
210 #ifndef _KERNEL
211 #define	INADDR_NONE		__IPADDR(0xffffffff)	/* -1 return */
212 #endif
213 
214 #define	INADDR_UNSPEC_GROUP	__IPADDR(0xe0000000)	/* 224.0.0.0 */
215 #define	INADDR_ALLHOSTS_GROUP	__IPADDR(0xe0000001)	/* 224.0.0.1 */
216 #define	INADDR_ALLRTRS_GROUP	__IPADDR(0xe0000002)	/* 224.0.0.2 */
217 #define	INADDR_MAX_LOCAL_GROUP	__IPADDR(0xe00000ff)	/* 224.0.0.255 */
218 
219 #define	IN_LOOPBACKNET		127			/* official! */
220 
221 /*
222  * Socket address, internet style.
223  */
224 struct sockaddr_in {
225 	uint8_t		sin_len;
226 	sa_family_t	sin_family;
227 	in_port_t	sin_port;
228 	struct in_addr	sin_addr;
229 	__int8_t	sin_zero[8];
230 };
231 
232 #define	INET_ADDRSTRLEN                 16
233 
234 /*
235  * Structure used to describe IP options.
236  * Used to store options internally, to pass them to a process,
237  * or to restore options retrieved earlier.
238  * The ip_dst is used for the first-hop gateway when using a source route
239  * (this gets put into the header proper).
240  */
241 struct ip_opts {
242 	struct in_addr	ip_dst;		/* first hop, 0 w/o src rt */
243 #if defined(__cplusplus)
244 	__int8_t	Ip_opts[40];	/* actually variable in size */
245 #else
246 	__int8_t	ip_opts[40];	/* actually variable in size */
247 #endif
248 };
249 
250 /*
251  * Options for use with [gs]etsockopt at the IP level.
252  * First word of comment is data type; bool is stored in int.
253  */
254 #define	IP_OPTIONS		1    /* buf/ip_opts; set/get IP options */
255 #define	IP_HDRINCL		2    /* int; header is included with data */
256 #define	IP_TOS			3    /* int; IP type of service and preced. */
257 #define	IP_TTL			4    /* int; IP time to live */
258 #define	IP_RECVOPTS		5    /* bool; receive all IP opts w/dgram */
259 #define	IP_RECVRETOPTS		6    /* bool; receive IP opts for response */
260 #define	IP_RECVDSTADDR		7    /* bool; receive IP dst addr w/dgram */
261 #define	IP_RETOPTS		8    /* ip_opts; set/get IP options */
262 #define	IP_MULTICAST_IF		9    /* in_addr; set/get IP multicast i/f  */
263 #define	IP_MULTICAST_TTL	10   /* u_char; set/get IP multicast ttl */
264 #define	IP_MULTICAST_LOOP	11   /* u_char; set/get IP multicast loopback */
265 #define	IP_ADD_MEMBERSHIP	12   /* ip_mreq; add an IP group membership */
266 #define	IP_DROP_MEMBERSHIP	13   /* ip_mreq; drop an IP group membership */
267 #define	IP_PORTRANGE		19   /* int; range to use for ephemeral port */
268 #define	IP_RECVIF		20   /* bool; receive reception if w/dgram */
269 #define	IP_ERRORMTU		21   /* int; get MTU of last xmit = EMSGSIZE */
270 #if 1 /*IPSEC*/
271 #define	IP_IPSEC_POLICY		22 /* struct; get/set security policy */
272 #endif
273 
274 /*
275  * Defaults and limits for options
276  */
277 #define	IP_DEFAULT_MULTICAST_TTL  1	/* normally limit m'casts to 1 hop  */
278 #define	IP_DEFAULT_MULTICAST_LOOP 1	/* normally hear sends if a member  */
279 #define	IP_MAX_MEMBERSHIPS	20	/* per socket; must fit in one mbuf */
280 
281 /*
282  * Argument structure for IP_ADD_MEMBERSHIP and IP_DROP_MEMBERSHIP.
283  */
284 struct ip_mreq {
285 	struct	in_addr imr_multiaddr;	/* IP multicast address of group */
286 	struct	in_addr imr_interface;	/* local IP address of interface */
287 };
288 
289 /*
290  * Argument for IP_PORTRANGE:
291  * - which range to search when port is unspecified at bind() or connect()
292  */
293 #define	IP_PORTRANGE_DEFAULT	0	/* default range */
294 #define	IP_PORTRANGE_HIGH	1	/* same as DEFAULT (FreeBSD compat) */
295 #define	IP_PORTRANGE_LOW	2	/* use privileged range */
296 
297 #if defined(_NETBSD_SOURCE)
298 /*
299  * Definitions for inet sysctl operations.
300  *
301  * Third level is protocol number.
302  * Fourth level is desired variable within that protocol.
303  */
304 #define	IPPROTO_MAXID	(IPPROTO_AH + 1)	/* don't list to IPPROTO_MAX */
305 
306 #define	CTL_IPPROTO_NAMES { \
307 	{ "ip", CTLTYPE_NODE }, \
308 	{ "icmp", CTLTYPE_NODE }, \
309 	{ "igmp", CTLTYPE_NODE }, \
310 	{ "ggp", CTLTYPE_NODE }, \
311 	{ 0, 0 }, \
312 	{ 0, 0 }, \
313 	{ "tcp", CTLTYPE_NODE }, \
314 	{ 0, 0 }, \
315 	{ "egp", CTLTYPE_NODE }, \
316 	{ 0, 0 }, \
317 	{ 0, 0 }, \
318 	{ 0, 0 }, \
319 	{ "pup", CTLTYPE_NODE }, \
320 	{ 0, 0 }, \
321 	{ 0, 0 }, \
322 	{ 0, 0 }, \
323 	{ 0, 0 }, \
324 	{ "udp", CTLTYPE_NODE }, \
325 	{ 0, 0 }, \
326 	{ 0, 0 }, \
327 	{ 0, 0 }, \
328 	{ 0, 0 }, \
329 	{ "idp", CTLTYPE_NODE }, \
330 	{ 0, 0 }, \
331 	{ 0, 0 }, \
332 	{ 0, 0 }, \
333 	{ 0, 0 }, \
334 	{ 0, 0 }, \
335 	{ 0, 0 }, \
336 	{ 0, 0 }, \
337 	{ 0, 0 }, \
338 	{ 0, 0 }, \
339 	{ 0, 0 }, \
340 	{ 0, 0 }, \
341 	{ 0, 0 }, \
342 	{ 0, 0 }, \
343 	{ 0, 0 }, \
344 	{ 0, 0 }, \
345 	{ 0, 0 }, \
346 	{ 0, 0 }, \
347 	{ 0, 0 }, \
348 	{ 0, 0 }, \
349 	{ 0, 0 }, \
350 	{ 0, 0 }, \
351 	{ 0, 0 }, \
352 	{ 0, 0 }, \
353 	{ 0, 0 }, \
354 	{ 0, 0 }, \
355 	{ 0, 0 }, \
356 	{ 0, 0 }, \
357 	{ 0, 0 }, \
358 	{ "ipsec", CTLTYPE_NODE }, \
359 	{ 0, 0 }, \
360 	{ 0, 0 }, \
361 	{ 0, 0 }, \
362 	{ 0, 0 }, \
363 	{ 0, 0 }, \
364 	{ 0, 0 }, \
365 	{ 0, 0 }, \
366 	{ 0, 0 }, \
367 	{ 0, 0 }, \
368 	{ 0, 0 }, \
369 	{ 0, 0 }, \
370 	{ 0, 0 }, \
371 	{ 0, 0 }, \
372 	{ 0, 0 }, \
373 	{ 0, 0 }, \
374 	{ 0, 0 }, \
375 	{ 0, 0 }, \
376 	{ 0, 0 }, \
377 	{ 0, 0 }, \
378 	{ 0, 0 }, \
379 	{ 0, 0 }, \
380 	{ 0, 0 }, \
381 	{ 0, 0 }, \
382 	{ 0, 0 }, \
383 	{ 0, 0 }, \
384 	{ 0, 0 }, \
385 	{ 0, 0 }, \
386 	{ 0, 0 }, \
387 	{ 0, 0 }, \
388 	{ 0, 0 }, \
389 	{ 0, 0 }, \
390 	{ 0, 0 }, \
391 	{ 0, 0 }, \
392 	{ 0, 0 }, \
393 	{ 0, 0 }, \
394 	{ 0, 0 }, \
395 	{ 0, 0 }, \
396 	{ 0, 0 }, \
397 	{ 0, 0 }, \
398 	{ 0, 0 }, \
399 	{ 0, 0 }, \
400 	{ 0, 0 }, \
401 	{ 0, 0 }, \
402 	{ 0, 0 }, \
403 	{ 0, 0 }, \
404 	{ 0, 0 }, \
405 	{ 0, 0 }, \
406 	{ 0, 0 }, \
407 	{ 0, 0 }, \
408 	{ 0, 0 }, \
409 	{ 0, 0 }, \
410 	{ "pim", CTLTYPE_NODE }, \
411 }
412 
413 /*
414  * Names for IP sysctl objects
415  */
416 #define	IPCTL_FORWARDING	1	/* act as router */
417 #define	IPCTL_SENDREDIRECTS	2	/* may send redirects when forwarding */
418 #define	IPCTL_DEFTTL		3	/* default TTL */
419 #ifdef notyet
420 #define	IPCTL_DEFMTU		4	/* default MTU */
421 #endif
422 #define	IPCTL_FORWSRCRT		5	/* forward source-routed packets */
423 #define	IPCTL_DIRECTEDBCAST	6	/* default broadcast behavior */
424 #define	IPCTL_ALLOWSRCRT	7	/* allow/drop all source-routed pkts */
425 #define	IPCTL_SUBNETSARELOCAL	8	/* treat subnets as local addresses */
426 #define	IPCTL_MTUDISC		9	/* allow path MTU discovery */
427 #define	IPCTL_ANONPORTMIN      10	/* minimum ephemeral port */
428 #define	IPCTL_ANONPORTMAX      11	/* maximum ephemeral port */
429 #define	IPCTL_MTUDISCTIMEOUT   12	/* allow path MTU discovery */
430 #define	IPCTL_MAXFLOWS         13	/* maximum ip flows allowed */
431 #define	IPCTL_HOSTZEROBROADCAST 14	/* is host zero a broadcast addr? */
432 #define	IPCTL_GIF_TTL 	       15	/* default TTL for gif encap packet */
433 #define	IPCTL_LOWPORTMIN       16	/* minimum reserved port */
434 #define	IPCTL_LOWPORTMAX       17	/* maximum reserved port */
435 #define	IPCTL_MAXFRAGPACKETS   18	/* max packets reassembly queue */
436 #define	IPCTL_GRE_TTL          19	/* default TTL for gre encap packet */
437 #define	IPCTL_CHECKINTERFACE   20	/* drop pkts in from 'wrong' iface */
438 #define	IPCTL_IFQ	       21	/* ipintrq node */
439 #define	IPCTL_RANDOMID	       22	/* use random IP ids (if configured) */
440 #define	IPCTL_MAXID	       23
441 
442 #define	IPCTL_NAMES { \
443 	{ 0, 0 }, \
444 	{ "forwarding", CTLTYPE_INT }, \
445 	{ "redirect", CTLTYPE_INT }, \
446 	{ "ttl", CTLTYPE_INT }, \
447 	{ "mtu", CTLTYPE_INT }, \
448 	{ "forwsrcrt", CTLTYPE_INT }, \
449 	{ "directed-broadcast", CTLTYPE_INT }, \
450 	{ "allowsrcrt", CTLTYPE_INT }, \
451 	{ "subnetsarelocal", CTLTYPE_INT }, \
452 	{ "mtudisc", CTLTYPE_INT }, \
453 	{ "anonportmin", CTLTYPE_INT }, \
454 	{ "anonportmax", CTLTYPE_INT }, \
455 	{ "mtudisctimeout", CTLTYPE_INT }, \
456 	{ "maxflows", CTLTYPE_INT }, \
457 	{ "hostzerobroadcast", CTLTYPE_INT }, \
458 	{ "gifttl", CTLTYPE_INT }, \
459 	{ "lowportmin", CTLTYPE_INT }, \
460 	{ "lowportmax", CTLTYPE_INT }, \
461 	{ "maxfragpackets", CTLTYPE_INT }, \
462 	{ "grettl", CTLTYPE_INT }, \
463 	{ "checkinterface", CTLTYPE_INT }, \
464 	{ "ifq", CTLTYPE_NODE }, \
465 	{ "random_id", CTLTYPE_INT }, \
466 }
467 #endif /* _NETBSD_SOURCE */
468 
469 /* INET6 stuff */
470 #define	__KAME_NETINET_IN_H_INCLUDED_
471 #include <netinet6/in6.h>
472 #undef __KAME_NETINET_IN_H_INCLUDED_
473 
474 #ifdef _KERNEL
475 /*
476  * in_cksum_phdr:
477  *
478  *	Compute significant parts of the IPv4 checksum pseudo-header
479  *	for use in a delayed TCP/UDP checksum calculation.
480  *
481  *	Args:
482  *
483  *		src		Source IP address
484  *		dst		Destination IP address
485  *		lenproto	htons(proto-hdr-len + proto-number)
486  */
487 static __inline u_int16_t __attribute__((__unused__))
488 in_cksum_phdr(u_int32_t src, u_int32_t dst, u_int32_t lenproto)
489 {
490 	u_int32_t sum;
491 
492 	sum = lenproto +
493 	      (u_int16_t)(src >> 16) +
494 	      (u_int16_t)(src /*& 0xffff*/) +
495 	      (u_int16_t)(dst >> 16) +
496 	      (u_int16_t)(dst /*& 0xffff*/);
497 
498 	sum = (u_int16_t)(sum >> 16) + (u_int16_t)(sum /*& 0xffff*/);
499 
500 	if (sum > 0xffff)
501 		sum -= 0xffff;
502 
503 	return (sum);
504 }
505 
506 /*
507  * in_cksum_addword:
508  *
509  *	Add the two 16-bit network-order values, carry, and return.
510  */
511 static __inline u_int16_t __attribute__((__unused__))
512 in_cksum_addword(u_int16_t a, u_int16_t b)
513 {
514 	u_int32_t sum = a + b;
515 
516 	if (sum > 0xffff)
517 		sum -= 0xffff;
518 
519 	return (sum);
520 }
521 
522 extern	struct in_addr zeroin_addr;
523 extern	u_char	ip_protox[];
524 
525 int	in_broadcast(struct in_addr, struct ifnet *);
526 int	in_canforward(struct in_addr);
527 int	in_cksum(struct mbuf *, int);
528 int	in4_cksum(struct mbuf *, u_int8_t, int, int);
529 void	in_delayed_cksum(struct mbuf *);
530 int	in_localaddr(struct in_addr);
531 void	in_socktrim(struct sockaddr_in *);
532 
533 #define	in_hosteq(s,t)	((s).s_addr == (t).s_addr)
534 #define	in_nullhost(x)	((x).s_addr == INADDR_ANY)
535 
536 #define	satosin(sa)	((struct sockaddr_in *)(sa))
537 #define	sintosa(sin)	((struct sockaddr *)(sin))
538 #define	ifatoia(ifa)	((struct in_ifaddr *)(ifa))
539 #endif /* _KERNEL */
540 
541 #endif /* !_NETINET_IN_H_ */
542