ip.h

  1/* SPDX-License-Identifier: GPL-2.0-or-later */
  2/*
  3 * INET		An implementation of the TCP/IP protocol suite for the LINUX
  4 *		operating system.  INET is implemented using the  BSD Socket
  5 *		interface as the means of communication with the user level.
  6 *
  7 *		Definitions for the IP module.
  8 *
  9 * Version:	@(#)ip.h	1.0.2	05/07/93
 10 *
 11 * Authors:	Ross Biro
 12 *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
 13 *		Alan Cox, <gw4pts@gw4pts.ampr.org>
 14 *
 15 * Changes:
 16 *		Mike McLagan    :       Routing by source
 17 */
 18#ifndef _IP_H
 19#define _IP_H
 20
 21#include <linux/types.h>
 22#include <linux/ip.h>
 23#include <linux/in.h>
 24#include <linux/skbuff.h>
 25#include <linux/jhash.h>
 26#include <linux/sockptr.h>
 27#include <linux/static_key.h>
 28
 29#include <net/inet_sock.h>
 30#include <net/route.h>
 31#include <net/snmp.h>
 32#include <net/flow.h>
 33#include <net/flow_dissector.h>
 34#include <net/netns/hash.h>
 35#include <net/lwtunnel.h>
 36#include <net/inet_dscp.h>
 37
 38#define IPV4_MAX_PMTU		65535U		/* RFC 2675, Section 5.1 */
 39#define IPV4_MIN_MTU		68			/* RFC 791 */
 40
 41extern unsigned int sysctl_fib_sync_mem;
 42extern unsigned int sysctl_fib_sync_mem_min;
 43extern unsigned int sysctl_fib_sync_mem_max;
 44
 45struct sock;
 46
 47struct inet_skb_parm {
 48	int			iif;
 49	struct ip_options	opt;		/* Compiled IP options		*/
 50	u16			flags;
 51
 52#define IPSKB_FORWARDED		BIT(0)
 53#define IPSKB_XFRM_TUNNEL_SIZE	BIT(1)
 54#define IPSKB_XFRM_TRANSFORMED	BIT(2)
 55#define IPSKB_FRAG_COMPLETE	BIT(3)
 56#define IPSKB_REROUTED		BIT(4)
 57#define IPSKB_DOREDIRECT	BIT(5)
 58#define IPSKB_FRAG_PMTU		BIT(6)
 59#define IPSKB_L3SLAVE		BIT(7)
 60#define IPSKB_NOPOLICY		BIT(8)
 61#define IPSKB_MULTIPATH		BIT(9)
 62#define IPSKB_MCROUTE		BIT(10)
 63
 64	u16			frag_max_size;
 65};
 66
 67static inline bool ipv4_l3mdev_skb(u16 flags)
 68{
 69	return !!(flags & IPSKB_L3SLAVE);
 70}
 71
 72static inline unsigned int ip_hdrlen(const struct sk_buff *skb)
 73{
 74	return ip_hdr(skb)->ihl * 4;
 75}
 76
 77struct ipcm_cookie {
 78	struct sockcm_cookie	sockc;
 79	__be32			addr;
 80	int			oif;
 81	struct ip_options_rcu	*opt;
 82	__u8			protocol;
 83	__u8			ttl;
 84	__s16			tos;
 85	__u16			gso_size;
 86};
 87
 88static inline void ipcm_init(struct ipcm_cookie *ipcm)
 89{
 90	*ipcm = (struct ipcm_cookie) { .tos = -1 };
 91}
 92
 93static inline void ipcm_init_sk(struct ipcm_cookie *ipcm,
 94				const struct inet_sock *inet)
 95{
 96	*ipcm = (struct ipcm_cookie) {
 97		.tos = READ_ONCE(inet->tos),
 98	};
 99
100	sockcm_init(&ipcm->sockc, &inet->sk);
101
102	ipcm->oif = READ_ONCE(inet->sk.sk_bound_dev_if);
103	ipcm->addr = inet->inet_saddr;
104	ipcm->protocol = READ_ONCE(inet->inet_num);
105}
106
107#define IPCB(skb) ((struct inet_skb_parm*)((skb)->cb))
108#define PKTINFO_SKB_CB(skb) ((struct in_pktinfo *)((skb)->cb))
109
110/* return enslaved device index if relevant */
111static inline int inet_sdif(const struct sk_buff *skb)
112{
113#if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
114	if (skb && ipv4_l3mdev_skb(IPCB(skb)->flags))
115		return IPCB(skb)->iif;
116#endif
117	return 0;
118}
119
120/* Special input handler for packets caught by router alert option.
121   They are selected only by protocol field, and then processed likely
122   local ones; but only if someone wants them! Otherwise, router
123   not running rsvpd will kill RSVP.
124
125   It is user level problem, what it will make with them.
126   I have no idea, how it will masquearde or NAT them (it is joke, joke :-)),
127   but receiver should be enough clever f.e. to forward mtrace requests,
128   sent to multicast group to reach destination designated router.
129 */
130
131struct ip_ra_chain {
132	struct ip_ra_chain __rcu *next;
133	struct sock		*sk;
134	union {
135		void			(*destructor)(struct sock *);
136		struct sock		*saved_sk;
137	};
138	struct rcu_head		rcu;
139};
140
141/* IP flags. */
142#define IP_CE		0x8000		/* Flag: "Congestion"		*/
143#define IP_DF		0x4000		/* Flag: "Don't Fragment"	*/
144#define IP_MF		0x2000		/* Flag: "More Fragments"	*/
145#define IP_OFFSET	0x1FFF		/* "Fragment Offset" part	*/
146
147#define IP_FRAG_TIME	(30 * HZ)		/* fragment lifetime	*/
148
149struct msghdr;
150struct net_device;
151struct packet_type;
152struct rtable;
153struct sockaddr;
154
155int igmp_mc_init(void);
156
157/*
158 *	Functions provided by ip.c
159 */
160
161int ip_build_and_send_pkt(struct sk_buff *skb, const struct sock *sk,
162			  __be32 saddr, __be32 daddr,
163			  struct ip_options_rcu *opt, u8 tos);
164int ip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt,
165	   struct net_device *orig_dev);
166void ip_list_rcv(struct list_head *head, struct packet_type *pt,
167		 struct net_device *orig_dev);
168int ip_local_deliver(struct sk_buff *skb);
169void ip_protocol_deliver_rcu(struct net *net, struct sk_buff *skb, int proto);
170int ip_mr_input(struct sk_buff *skb);
171int ip_mr_output(struct net *net, struct sock *sk, struct sk_buff *skb);
172int ip_output(struct net *net, struct sock *sk, struct sk_buff *skb);
173int ip_mc_output(struct net *net, struct sock *sk, struct sk_buff *skb);
174int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
175		   int (*output)(struct net *, struct sock *, struct sk_buff *));
176
177struct ip_fraglist_iter {
178	struct sk_buff	*frag;
179	struct iphdr	*iph;
180	int		offset;
181	unsigned int	hlen;
182};
183
184void ip_fraglist_init(struct sk_buff *skb, struct iphdr *iph,
185		      unsigned int hlen, struct ip_fraglist_iter *iter);
186void ip_fraglist_prepare(struct sk_buff *skb, struct ip_fraglist_iter *iter);
187
188static inline struct sk_buff *ip_fraglist_next(struct ip_fraglist_iter *iter)
189{
190	struct sk_buff *skb = iter->frag;
191
192	iter->frag = skb->next;
193	skb_mark_not_on_list(skb);
194
195	return skb;
196}
197
198struct ip_frag_state {
199	bool		DF;
200	unsigned int	hlen;
201	unsigned int	ll_rs;
202	unsigned int	mtu;
203	unsigned int	left;
204	int		offset;
205	int		ptr;
206	__be16		not_last_frag;
207};
208
209void ip_frag_init(struct sk_buff *skb, unsigned int hlen, unsigned int ll_rs,
210		  unsigned int mtu, bool DF, struct ip_frag_state *state);
211struct sk_buff *ip_frag_next(struct sk_buff *skb,
212			     struct ip_frag_state *state);
213
214void ip_send_check(struct iphdr *ip);
215int __ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb);
216int ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb);
217
218int __ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl,
219		    __u8 tos);
220void ip_init(void);
221int ip_append_data(struct sock *sk, struct flowi4 *fl4,
222		   int getfrag(void *from, char *to, int offset, int len,
223			       int odd, struct sk_buff *skb),
224		   void *from, int len, int protolen,
225		   struct ipcm_cookie *ipc,
226		   struct rtable **rt,
227		   unsigned int flags);
228int ip_generic_getfrag(void *from, char *to, int offset, int len, int odd,
229		       struct sk_buff *skb);
230struct sk_buff *__ip_make_skb(struct sock *sk, struct flowi4 *fl4,
231			      struct sk_buff_head *queue,
232			      struct inet_cork *cork);
233int ip_send_skb(struct net *net, struct sk_buff *skb);
234int ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4);
235void ip_flush_pending_frames(struct sock *sk);
236struct sk_buff *ip_make_skb(struct sock *sk, struct flowi4 *fl4,
237			    int getfrag(void *from, char *to, int offset,
238					int len, int odd, struct sk_buff *skb),
239			    void *from, int length, int transhdrlen,
240			    struct ipcm_cookie *ipc, struct rtable **rtp,
241			    struct inet_cork *cork, unsigned int flags);
242
243int ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl);
244
245static inline struct sk_buff *ip_finish_skb(struct sock *sk, struct flowi4 *fl4)
246{
247	return __ip_make_skb(sk, fl4, &sk->sk_write_queue, &inet_sk(sk)->cork.base);
248}
249
250/* Get the route scope that should be used when sending a packet. */
251static inline u8 ip_sendmsg_scope(const struct inet_sock *inet,
252				  const struct ipcm_cookie *ipc,
253				  const struct msghdr *msg)
254{
255	if (sock_flag(&inet->sk, SOCK_LOCALROUTE) ||
256	    msg->msg_flags & MSG_DONTROUTE ||
257	    (ipc->opt && ipc->opt->opt.is_strictroute))
258		return RT_SCOPE_LINK;
259
260	return RT_SCOPE_UNIVERSE;
261}
262
263/* datagram.c */
264int __ip4_datagram_connect(struct sock *sk, struct sockaddr_unsized *uaddr, int addr_len);
265int ip4_datagram_connect(struct sock *sk, struct sockaddr_unsized *uaddr, int addr_len);
266
267void ip4_datagram_release_cb(struct sock *sk);
268
269struct ip_reply_arg {
270	struct kvec iov[1];
271	int	    flags;
272	__wsum 	    csum;
273	int	    csumoffset; /* u16 offset of csum in iov[0].iov_base */
274				/* -1 if not needed */
275	int	    bound_dev_if;
276	u8  	    tos;
277	kuid_t	    uid;
278};
279
280#define IP_REPLY_ARG_NOSRCCHECK 1
281
282static inline __u8 ip_reply_arg_flowi_flags(const struct ip_reply_arg *arg)
283{
284	return (arg->flags & IP_REPLY_ARG_NOSRCCHECK) ? FLOWI_FLAG_ANYSRC : 0;
285}
286
287void ip_send_unicast_reply(struct sock *sk, const struct sock *orig_sk,
288			   struct sk_buff *skb,
289			   const struct ip_options *sopt,
290			   __be32 daddr, __be32 saddr,
291			   const struct ip_reply_arg *arg,
292			   unsigned int len, u64 transmit_time, u32 txhash);
293
294#define IP_INC_STATS(net, field)	SNMP_INC_STATS64((net)->mib.ip_statistics, field)
295#define __IP_INC_STATS(net, field)	__SNMP_INC_STATS64((net)->mib.ip_statistics, field)
296#define IP_ADD_STATS(net, field, val)	SNMP_ADD_STATS64((net)->mib.ip_statistics, field, val)
297#define __IP_ADD_STATS(net, field, val) __SNMP_ADD_STATS64((net)->mib.ip_statistics, field, val)
298#define IP_UPD_PO_STATS(net, field, val) SNMP_UPD_PO_STATS64((net)->mib.ip_statistics, field, val)
299#define __IP_UPD_PO_STATS(net, field, val) __SNMP_UPD_PO_STATS64((net)->mib.ip_statistics, field, val)
300#define NET_INC_STATS(net, field)	SNMP_INC_STATS((net)->mib.net_statistics, field)
301#define __NET_INC_STATS(net, field)	__SNMP_INC_STATS((net)->mib.net_statistics, field)
302#define NET_ADD_STATS(net, field, adnd)	SNMP_ADD_STATS((net)->mib.net_statistics, field, adnd)
303#define __NET_ADD_STATS(net, field, adnd) __SNMP_ADD_STATS((net)->mib.net_statistics, field, adnd)
304
305static inline u64 snmp_get_cpu_field(void __percpu *mib, int cpu, int offt)
306{
307	return  *(((unsigned long *)per_cpu_ptr(mib, cpu)) + offt);
308}
309
310unsigned long snmp_fold_field(void __percpu *mib, int offt);
311#if BITS_PER_LONG==32
312u64 snmp_get_cpu_field64(void __percpu *mib, int cpu, int offct,
313			 size_t syncp_offset);
314u64 snmp_fold_field64(void __percpu *mib, int offt, size_t sync_off);
315#else
316static inline u64  snmp_get_cpu_field64(void __percpu *mib, int cpu, int offct,
317					size_t syncp_offset)
318{
319	return snmp_get_cpu_field(mib, cpu, offct);
320
321}
322
323static inline u64 snmp_fold_field64(void __percpu *mib, int offt, size_t syncp_off)
324{
325	return snmp_fold_field(mib, offt);
326}
327#endif
328
329#define snmp_get_cpu_field64_batch_cnt(buff64, stats_list, cnt,	\
330				       mib_statistic, offset)	\
331{ \
332	int i, c; \
333	for_each_possible_cpu(c) { \
334		for (i = 0; i < cnt; i++) \
335			buff64[i] += snmp_get_cpu_field64( \
336					mib_statistic, \
337					c, stats_list[i].entry, \
338					offset); \
339	} \
340}
341
342#define snmp_get_cpu_field_batch_cnt(buff, stats_list, cnt, mib_statistic) \
343{ \
344	int i, c; \
345	for_each_possible_cpu(c) { \
346		for (i = 0; i < cnt; i++) \
347			buff[i] += snmp_get_cpu_field( \
348						mib_statistic, \
349						c, stats_list[i].entry); \
350	} \
351}
352
353static inline void inet_get_local_port_range(const struct net *net, int *low, int *high)
354{
355	u32 range = READ_ONCE(net->ipv4.ip_local_ports.range);
356
357	*low = range & 0xffff;
358	*high = range >> 16;
359}
360bool inet_sk_get_local_port_range(const struct sock *sk, int *low, int *high);
361
362#ifdef CONFIG_SYSCTL
363static inline bool inet_is_local_reserved_port(const struct net *net, unsigned short port)
364{
365	if (!net->ipv4.sysctl_local_reserved_ports)
366		return false;
367	return test_bit(port, net->ipv4.sysctl_local_reserved_ports);
368}
369
370static inline bool sysctl_dev_name_is_allowed(const char *name)
371{
372	return strcmp(name, "default") != 0  && strcmp(name, "all") != 0;
373}
374
375static inline bool inet_port_requires_bind_service(struct net *net, unsigned short port)
376{
377	return port < READ_ONCE(net->ipv4.sysctl_ip_prot_sock);
378}
379
380#else
381static inline bool inet_is_local_reserved_port(struct net *net, unsigned short port)
382{
383	return false;
384}
385
386static inline bool inet_port_requires_bind_service(struct net *net, unsigned short port)
387{
388	return port < PROT_SOCK;
389}
390#endif
391
392__be32 inet_current_timestamp(void);
393
394/* From inetpeer.c */
395extern int inet_peer_threshold;
396extern int inet_peer_minttl;
397extern int inet_peer_maxttl;
398
399void ipfrag_init(void);
400
401void ip_static_sysctl_init(void);
402
403#define IP4_REPLY_MARK(net, mark) \
404	(READ_ONCE((net)->ipv4.sysctl_fwmark_reflect) ? (mark) : 0)
405
406static inline bool ip_is_fragment(const struct iphdr *iph)
407{
408	return (iph->frag_off & htons(IP_MF | IP_OFFSET)) != 0;
409}
410
411#ifdef CONFIG_INET
412#include <net/dst.h>
413
414/* The function in 2.2 was invalid, producing wrong result for
415 * check=0xFEFF. It was noticed by Arthur Skawina _year_ ago. --ANK(000625) */
416static inline
417int ip_decrease_ttl(struct iphdr *iph)
418{
419	u32 check = (__force u32)iph->check;
420	check += (__force u32)htons(0x0100);
421	iph->check = (__force __sum16)(check + (check>=0xFFFF));
422	return --iph->ttl;
423}
424
425static inline dscp_t ip4h_dscp(const struct iphdr *ip4h)
426{
427	return inet_dsfield_to_dscp(ip4h->tos);
428}
429
430static inline int ip_mtu_locked(const struct dst_entry *dst)
431{
432	const struct rtable *rt = dst_rtable(dst);
433
434	return rt->rt_mtu_locked || dst_metric_locked(dst, RTAX_MTU);
435}
436
437static inline
438int ip_dont_fragment(const struct sock *sk, const struct dst_entry *dst)
439{
440	u8 pmtudisc = READ_ONCE(inet_sk(sk)->pmtudisc);
441
442	return  pmtudisc == IP_PMTUDISC_DO ||
443		(pmtudisc == IP_PMTUDISC_WANT &&
444		 !ip_mtu_locked(dst));
445}
446
447static inline bool ip_sk_accept_pmtu(const struct sock *sk)
448{
449	u8 pmtudisc = READ_ONCE(inet_sk(sk)->pmtudisc);
450
451	return pmtudisc != IP_PMTUDISC_INTERFACE &&
452	       pmtudisc != IP_PMTUDISC_OMIT;
453}
454
455static inline bool ip_sk_use_pmtu(const struct sock *sk)
456{
457	return READ_ONCE(inet_sk(sk)->pmtudisc) < IP_PMTUDISC_PROBE;
458}
459
460static inline bool ip_sk_ignore_df(const struct sock *sk)
461{
462	u8 pmtudisc = READ_ONCE(inet_sk(sk)->pmtudisc);
463
464	return pmtudisc < IP_PMTUDISC_DO || pmtudisc == IP_PMTUDISC_OMIT;
465}
466
467static inline unsigned int ip_dst_mtu_maybe_forward(const struct dst_entry *dst,
468						    bool forwarding)
469{
470	const struct rtable *rt = dst_rtable(dst);
471	const struct net_device *dev;
472	unsigned int mtu, res;
473	struct net *net;
474
475	rcu_read_lock();
476
477	dev = dst_dev_rcu(dst);
478	net = dev_net_rcu(dev);
479	if (READ_ONCE(net->ipv4.sysctl_ip_fwd_use_pmtu) ||
480	    ip_mtu_locked(dst) ||
481	    !forwarding) {
482		mtu = rt->rt_pmtu;
483		if (mtu && time_before(jiffies, READ_ONCE(rt->dst.expires)))
484			goto out;
485	}
486
487	/* 'forwarding = true' case should always honour route mtu */
488	mtu = dst_metric_raw(dst, RTAX_MTU);
489	if (mtu)
490		goto out;
491
492	mtu = READ_ONCE(dev->mtu);
493
494	if (unlikely(ip_mtu_locked(dst))) {
495		if (rt->rt_uses_gateway && mtu > 576)
496			mtu = 576;
497	}
498
499out:
500	mtu = min_t(unsigned int, mtu, IP_MAX_MTU);
501
502	res = mtu - lwtunnel_headroom(dst->lwtstate, mtu);
503
504	rcu_read_unlock();
505
506	return res;
507}
508
509static inline unsigned int ip_skb_dst_mtu(struct sock *sk,
510					  const struct sk_buff *skb)
511{
512	const struct dst_entry *dst = skb_dst(skb);
513	unsigned int mtu;
514
515	if (!sk || !sk_fullsock(sk) || ip_sk_use_pmtu(sk)) {
516		bool forwarding = IPCB(skb)->flags & IPSKB_FORWARDED;
517
518		return ip_dst_mtu_maybe_forward(dst, forwarding);
519	}
520
521	mtu = min(READ_ONCE(dst_dev(dst)->mtu), IP_MAX_MTU);
522	return mtu - lwtunnel_headroom(dst->lwtstate, mtu);
523}
524
525struct dst_metrics *ip_fib_metrics_init(struct nlattr *fc_mx, int fc_mx_len,
526					struct netlink_ext_ack *extack);
527static inline void ip_fib_metrics_put(struct dst_metrics *fib_metrics)
528{
529	if (fib_metrics != &dst_default_metrics &&
530	    refcount_dec_and_test(&fib_metrics->refcnt))
531		kfree(fib_metrics);
532}
533
534/* ipv4 and ipv6 both use refcounted metrics if it is not the default */
535static inline
536void ip_dst_init_metrics(struct dst_entry *dst, struct dst_metrics *fib_metrics)
537{
538	dst_init_metrics(dst, fib_metrics->metrics, true);
539
540	if (fib_metrics != &dst_default_metrics) {
541		dst->_metrics |= DST_METRICS_REFCOUNTED;
542		refcount_inc(&fib_metrics->refcnt);
543	}
544}
545
546static inline
547void ip_dst_metrics_put(struct dst_entry *dst)
548{
549	struct dst_metrics *p = (struct dst_metrics *)DST_METRICS_PTR(dst);
550
551	if (p != &dst_default_metrics && refcount_dec_and_test(&p->refcnt))
552		kfree(p);
553}
554
555void __ip_select_ident(struct net *net, struct iphdr *iph, int segs);
556
557static inline void ip_select_ident_segs(struct net *net, struct sk_buff *skb,
558					struct sock *sk, int segs)
559{
560	struct iphdr *iph = ip_hdr(skb);
561
562	/* We had many attacks based on IPID, use the private
563	 * generator as much as we can.
564	 */
565	if (sk && inet_sk(sk)->inet_daddr) {
566		int val;
567
568		/* avoid atomic operations for TCP,
569		 * as we hold socket lock at this point.
570		 */
571		if (sk_is_tcp(sk)) {
572			sock_owned_by_me(sk);
573			val = atomic_read(&inet_sk(sk)->inet_id);
574			atomic_set(&inet_sk(sk)->inet_id, val + segs);
575		} else {
576			val = atomic_add_return(segs, &inet_sk(sk)->inet_id);
577		}
578		iph->id = htons(val);
579		return;
580	}
581	if ((iph->frag_off & htons(IP_DF)) && !skb->ignore_df) {
582		iph->id = 0;
583	} else {
584		/* Unfortunately we need the big hammer to get a suitable IPID */
585		__ip_select_ident(net, iph, segs);
586	}
587}
588
589static inline void ip_select_ident(struct net *net, struct sk_buff *skb,
590				   struct sock *sk)
591{
592	ip_select_ident_segs(net, skb, sk, 1);
593}
594
595static inline __wsum inet_compute_pseudo(struct sk_buff *skb, int proto)
596{
597	return csum_tcpudp_nofold(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
598				  skb->len, proto, 0);
599}
600
601/* copy IPv4 saddr & daddr to flow_keys, possibly using 64bit load/store
602 * Equivalent to :	flow->v4addrs.src = iph->saddr;
603 *			flow->v4addrs.dst = iph->daddr;
604 */
605static inline void iph_to_flow_copy_v4addrs(struct flow_keys *flow,
606					    const struct iphdr *iph)
607{
608	BUILD_BUG_ON(offsetof(typeof(flow->addrs), v4addrs.dst) !=
609		     offsetof(typeof(flow->addrs), v4addrs.src) +
610			      sizeof(flow->addrs.v4addrs.src));
611	memcpy(&flow->addrs.v4addrs, &iph->addrs, sizeof(flow->addrs.v4addrs));
612	flow->control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
613}
614
615/*
616 *	Map a multicast IP onto multicast MAC for type ethernet.
617 */
618
619static inline void ip_eth_mc_map(__be32 naddr, char *buf)
620{
621	__u32 addr=ntohl(naddr);
622	buf[0]=0x01;
623	buf[1]=0x00;
624	buf[2]=0x5e;
625	buf[5]=addr&0xFF;
626	addr>>=8;
627	buf[4]=addr&0xFF;
628	addr>>=8;
629	buf[3]=addr&0x7F;
630}
631
632/*
633 *	Map a multicast IP onto multicast MAC for type IP-over-InfiniBand.
634 *	Leave P_Key as 0 to be filled in by driver.
635 */
636
637static inline void ip_ib_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
638{
639	__u32 addr;
640	unsigned char scope = broadcast[5] & 0xF;
641
642	buf[0]  = 0;		/* Reserved */
643	buf[1]  = 0xff;		/* Multicast QPN */
644	buf[2]  = 0xff;
645	buf[3]  = 0xff;
646	addr    = ntohl(naddr);
647	buf[4]  = 0xff;
648	buf[5]  = 0x10 | scope;	/* scope from broadcast address */
649	buf[6]  = 0x40;		/* IPv4 signature */
650	buf[7]  = 0x1b;
651	buf[8]  = broadcast[8];		/* P_Key */
652	buf[9]  = broadcast[9];
653	buf[10] = 0;
654	buf[11] = 0;
655	buf[12] = 0;
656	buf[13] = 0;
657	buf[14] = 0;
658	buf[15] = 0;
659	buf[19] = addr & 0xff;
660	addr  >>= 8;
661	buf[18] = addr & 0xff;
662	addr  >>= 8;
663	buf[17] = addr & 0xff;
664	addr  >>= 8;
665	buf[16] = addr & 0x0f;
666}
667
668static inline void ip_ipgre_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
669{
670	if ((broadcast[0] | broadcast[1] | broadcast[2] | broadcast[3]) != 0)
671		memcpy(buf, broadcast, 4);
672	else
673		memcpy(buf, &naddr, sizeof(naddr));
674}
675
676#if IS_ENABLED(CONFIG_IPV6)
677#include <linux/ipv6.h>
678#endif
679
680static __inline__ void inet_reset_saddr(struct sock *sk)
681{
682	inet_sk(sk)->inet_rcv_saddr = inet_sk(sk)->inet_saddr = 0;
683#if IS_ENABLED(CONFIG_IPV6)
684	if (sk->sk_family == PF_INET6) {
685		struct ipv6_pinfo *np = inet6_sk(sk);
686
687		memset(&np->saddr, 0, sizeof(np->saddr));
688		memset(&sk->sk_v6_rcv_saddr, 0, sizeof(sk->sk_v6_rcv_saddr));
689	}
690#endif
691}
692
693#endif
694
695#if IS_MODULE(CONFIG_IPV6)
696#define EXPORT_IPV6_MOD(X) EXPORT_SYMBOL(X)
697#define EXPORT_IPV6_MOD_GPL(X) EXPORT_SYMBOL_GPL(X)
698#else
699#define EXPORT_IPV6_MOD(X)
700#define EXPORT_IPV6_MOD_GPL(X)
701#endif
702
703static inline unsigned int ipv4_addr_hash(__be32 ip)
704{
705	return (__force unsigned int) ip;
706}
707
708static inline u32 __ipv4_addr_hash(const __be32 ip, const u32 initval)
709{
710	return jhash_1word((__force u32)ip, initval);
711}
712
713static inline u32 ipv4_portaddr_hash(const struct net *net,
714				     __be32 saddr,
715				     unsigned int port)
716{
717	return jhash_1word((__force u32)saddr, net_hash_mix(net)) ^ port;
718}
719
720bool ip_call_ra_chain(struct sk_buff *skb);
721
722/*
723 *	Functions provided by ip_fragment.c
724 */
725
726enum ip_defrag_users {
727	IP_DEFRAG_LOCAL_DELIVER,
728	IP_DEFRAG_CALL_RA_CHAIN,
729	IP_DEFRAG_CONNTRACK_IN,
730	__IP_DEFRAG_CONNTRACK_IN_END	= IP_DEFRAG_CONNTRACK_IN + USHRT_MAX,
731	IP_DEFRAG_CONNTRACK_OUT,
732	__IP_DEFRAG_CONNTRACK_OUT_END	= IP_DEFRAG_CONNTRACK_OUT + USHRT_MAX,
733	IP_DEFRAG_CONNTRACK_BRIDGE_IN,
734	__IP_DEFRAG_CONNTRACK_BRIDGE_IN = IP_DEFRAG_CONNTRACK_BRIDGE_IN + USHRT_MAX,
735	IP_DEFRAG_VS_IN,
736	IP_DEFRAG_VS_OUT,
737	IP_DEFRAG_VS_FWD,
738	IP_DEFRAG_AF_PACKET,
739	IP_DEFRAG_MACVLAN,
740};
741
742/* Return true if the value of 'user' is between 'lower_bond'
743 * and 'upper_bond' inclusively.
744 */
745static inline bool ip_defrag_user_in_between(u32 user,
746					     enum ip_defrag_users lower_bond,
747					     enum ip_defrag_users upper_bond)
748{
749	return user >= lower_bond && user <= upper_bond;
750}
751
752int ip_defrag(struct net *net, struct sk_buff *skb, u32 user);
753#ifdef CONFIG_INET
754struct sk_buff *ip_check_defrag(struct net *net, struct sk_buff *skb, u32 user);
755#else
756static inline struct sk_buff *ip_check_defrag(struct net *net, struct sk_buff *skb, u32 user)
757{
758	return skb;
759}
760#endif
761
762/*
763 *	Functions provided by ip_forward.c
764 */
765
766int ip_forward(struct sk_buff *skb);
767
768/*
769 *	Functions provided by ip_options.c
770 */
771
772void ip_options_build(struct sk_buff *skb, struct ip_options *opt,
773		      __be32 daddr, struct rtable *rt);
774
775int __ip_options_echo(struct net *net, struct ip_options *dopt,
776		      struct sk_buff *skb, const struct ip_options *sopt);
777static inline int ip_options_echo(struct net *net, struct ip_options *dopt,
778				  struct sk_buff *skb)
779{
780	return __ip_options_echo(net, dopt, skb, &IPCB(skb)->opt);
781}
782
783void ip_options_fragment(struct sk_buff *skb);
784int __ip_options_compile(struct net *net, struct ip_options *opt,
785			 struct sk_buff *skb, __be32 *info);
786int ip_options_compile(struct net *net, struct ip_options *opt,
787		       struct sk_buff *skb);
788int ip_options_get(struct net *net, struct ip_options_rcu **optp,
789		   sockptr_t data, int optlen);
790void ip_options_undo(struct ip_options *opt);
791void ip_forward_options(struct sk_buff *skb);
792int ip_options_rcv_srr(struct sk_buff *skb, struct net_device *dev);
793
794/*
795 *	Functions provided by ip_sockglue.c
796 */
797
798void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb, bool drop_dst);
799void ip_cmsg_recv_offset(struct msghdr *msg, struct sock *sk,
800			 struct sk_buff *skb, int tlen, int offset);
801int ip_cmsg_send(struct sock *sk, struct msghdr *msg,
802		 struct ipcm_cookie *ipc, bool allow_ipv6);
803DECLARE_STATIC_KEY_FALSE(ip4_min_ttl);
804int do_ip_setsockopt(struct sock *sk, int level, int optname, sockptr_t optval,
805		     unsigned int optlen);
806int ip_setsockopt(struct sock *sk, int level, int optname, sockptr_t optval,
807		  unsigned int optlen);
808int do_ip_getsockopt(struct sock *sk, int level, int optname,
809		     sockptr_t optval, sockptr_t optlen);
810int ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
811		  int __user *optlen);
812int ip_ra_control(struct sock *sk, unsigned char on,
813		  void (*destructor)(struct sock *));
814
815int ip_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len);
816void ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err, __be16 port,
817		   u32 info, u8 *payload);
818void ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 dport,
819		    u32 info);
820
821static inline void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb)
822{
823	ip_cmsg_recv_offset(msg, skb->sk, skb, 0, 0);
824}
825
826bool icmp_global_allow(struct net *net);
827void icmp_global_consume(struct net *net);
828
829#ifdef CONFIG_PROC_FS
830int ip_misc_proc_init(void);
831#endif
832
833int rtm_getroute_parse_ip_proto(struct nlattr *attr, u8 *ip_proto, u8 family,
834				struct netlink_ext_ack *extack);
835
836static inline bool inetdev_valid_mtu(unsigned int mtu)
837{
838	return likely(mtu >= IPV4_MIN_MTU);
839}
840
841void ip_sock_set_freebind(struct sock *sk);
842int ip_sock_set_mtu_discover(struct sock *sk, int val);
843void ip_sock_set_pktinfo(struct sock *sk);
844void ip_sock_set_recverr(struct sock *sk);
845void ip_sock_set_tos(struct sock *sk, int val);
846void  __ip_sock_set_tos(struct sock *sk, int val);
847
848#endif	/* _IP_H */