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  
37  #define IPV4_MAX_PMTU		65535U		/* RFC 2675, Section 5.1 */
38  #define IPV4_MIN_MTU		68			/* RFC 791 */
39  
40  extern unsigned int sysctl_fib_sync_mem;
41  extern unsigned int sysctl_fib_sync_mem_min;
42  extern unsigned int sysctl_fib_sync_mem_max;
43  
44  struct sock;
45  
46  struct inet_skb_parm {
47  	int			iif;
48  	struct ip_options	opt;		/* Compiled IP options		*/
49  	u16			flags;
50  
51  #define IPSKB_FORWARDED		BIT(0)
52  #define IPSKB_XFRM_TUNNEL_SIZE	BIT(1)
53  #define IPSKB_XFRM_TRANSFORMED	BIT(2)
54  #define IPSKB_FRAG_COMPLETE	BIT(3)
55  #define IPSKB_REROUTED		BIT(4)
56  #define IPSKB_DOREDIRECT	BIT(5)
57  #define IPSKB_FRAG_PMTU		BIT(6)
58  #define IPSKB_L3SLAVE		BIT(7)
59  #define IPSKB_NOPOLICY		BIT(8)
60  
61  	u16			frag_max_size;
62  };
63  
ipv4_l3mdev_skb(u16 flags)64  static inline bool ipv4_l3mdev_skb(u16 flags)
65  {
66  	return !!(flags & IPSKB_L3SLAVE);
67  }
68  
ip_hdrlen(const struct sk_buff * skb)69  static inline unsigned int ip_hdrlen(const struct sk_buff *skb)
70  {
71  	return ip_hdr(skb)->ihl * 4;
72  }
73  
74  struct ipcm_cookie {
75  	struct sockcm_cookie	sockc;
76  	__be32			addr;
77  	int			oif;
78  	struct ip_options_rcu	*opt;
79  	__u8			ttl;
80  	__s16			tos;
81  	char			priority;
82  	__u16			gso_size;
83  };
84  
ipcm_init(struct ipcm_cookie * ipcm)85  static inline void ipcm_init(struct ipcm_cookie *ipcm)
86  {
87  	*ipcm = (struct ipcm_cookie) { .tos = -1 };
88  }
89  
ipcm_init_sk(struct ipcm_cookie * ipcm,const struct inet_sock * inet)90  static inline void ipcm_init_sk(struct ipcm_cookie *ipcm,
91  				const struct inet_sock *inet)
92  {
93  	ipcm_init(ipcm);
94  
95  	ipcm->sockc.mark = inet->sk.sk_mark;
96  	ipcm->sockc.tsflags = inet->sk.sk_tsflags;
97  	ipcm->oif = READ_ONCE(inet->sk.sk_bound_dev_if);
98  	ipcm->addr = inet->inet_saddr;
99  }
100  
101  #define IPCB(skb) ((struct inet_skb_parm*)((skb)->cb))
102  #define PKTINFO_SKB_CB(skb) ((struct in_pktinfo *)((skb)->cb))
103  
104  /* return enslaved device index if relevant */
inet_sdif(const struct sk_buff * skb)105  static inline int inet_sdif(const struct sk_buff *skb)
106  {
107  #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
108  	if (skb && ipv4_l3mdev_skb(IPCB(skb)->flags))
109  		return IPCB(skb)->iif;
110  #endif
111  	return 0;
112  }
113  
114  /* Special input handler for packets caught by router alert option.
115     They are selected only by protocol field, and then processed likely
116     local ones; but only if someone wants them! Otherwise, router
117     not running rsvpd will kill RSVP.
118  
119     It is user level problem, what it will make with them.
120     I have no idea, how it will masquearde or NAT them (it is joke, joke :-)),
121     but receiver should be enough clever f.e. to forward mtrace requests,
122     sent to multicast group to reach destination designated router.
123   */
124  
125  struct ip_ra_chain {
126  	struct ip_ra_chain __rcu *next;
127  	struct sock		*sk;
128  	union {
129  		void			(*destructor)(struct sock *);
130  		struct sock		*saved_sk;
131  	};
132  	struct rcu_head		rcu;
133  };
134  
135  /* IP flags. */
136  #define IP_CE		0x8000		/* Flag: "Congestion"		*/
137  #define IP_DF		0x4000		/* Flag: "Don't Fragment"	*/
138  #define IP_MF		0x2000		/* Flag: "More Fragments"	*/
139  #define IP_OFFSET	0x1FFF		/* "Fragment Offset" part	*/
140  
141  #define IP_FRAG_TIME	(30 * HZ)		/* fragment lifetime	*/
142  
143  struct msghdr;
144  struct net_device;
145  struct packet_type;
146  struct rtable;
147  struct sockaddr;
148  
149  int igmp_mc_init(void);
150  
151  /*
152   *	Functions provided by ip.c
153   */
154  
155  int ip_build_and_send_pkt(struct sk_buff *skb, const struct sock *sk,
156  			  __be32 saddr, __be32 daddr,
157  			  struct ip_options_rcu *opt, u8 tos);
158  int ip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt,
159  	   struct net_device *orig_dev);
160  void ip_list_rcv(struct list_head *head, struct packet_type *pt,
161  		 struct net_device *orig_dev);
162  int ip_local_deliver(struct sk_buff *skb);
163  void ip_protocol_deliver_rcu(struct net *net, struct sk_buff *skb, int proto);
164  int ip_mr_input(struct sk_buff *skb);
165  int ip_output(struct net *net, struct sock *sk, struct sk_buff *skb);
166  int ip_mc_output(struct net *net, struct sock *sk, struct sk_buff *skb);
167  int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
168  		   int (*output)(struct net *, struct sock *, struct sk_buff *));
169  
170  struct ip_fraglist_iter {
171  	struct sk_buff	*frag;
172  	struct iphdr	*iph;
173  	int		offset;
174  	unsigned int	hlen;
175  };
176  
177  void ip_fraglist_init(struct sk_buff *skb, struct iphdr *iph,
178  		      unsigned int hlen, struct ip_fraglist_iter *iter);
179  void ip_fraglist_prepare(struct sk_buff *skb, struct ip_fraglist_iter *iter);
180  
ip_fraglist_next(struct ip_fraglist_iter * iter)181  static inline struct sk_buff *ip_fraglist_next(struct ip_fraglist_iter *iter)
182  {
183  	struct sk_buff *skb = iter->frag;
184  
185  	iter->frag = skb->next;
186  	skb_mark_not_on_list(skb);
187  
188  	return skb;
189  }
190  
191  struct ip_frag_state {
192  	bool		DF;
193  	unsigned int	hlen;
194  	unsigned int	ll_rs;
195  	unsigned int	mtu;
196  	unsigned int	left;
197  	int		offset;
198  	int		ptr;
199  	__be16		not_last_frag;
200  };
201  
202  void ip_frag_init(struct sk_buff *skb, unsigned int hlen, unsigned int ll_rs,
203  		  unsigned int mtu, bool DF, struct ip_frag_state *state);
204  struct sk_buff *ip_frag_next(struct sk_buff *skb,
205  			     struct ip_frag_state *state);
206  
207  void ip_send_check(struct iphdr *ip);
208  int __ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb);
209  int ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb);
210  
211  int __ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl,
212  		    __u8 tos);
213  void ip_init(void);
214  int ip_append_data(struct sock *sk, struct flowi4 *fl4,
215  		   int getfrag(void *from, char *to, int offset, int len,
216  			       int odd, struct sk_buff *skb),
217  		   void *from, int len, int protolen,
218  		   struct ipcm_cookie *ipc,
219  		   struct rtable **rt,
220  		   unsigned int flags);
221  int ip_generic_getfrag(void *from, char *to, int offset, int len, int odd,
222  		       struct sk_buff *skb);
223  ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,
224  		       int offset, size_t size, int flags);
225  struct sk_buff *__ip_make_skb(struct sock *sk, struct flowi4 *fl4,
226  			      struct sk_buff_head *queue,
227  			      struct inet_cork *cork);
228  int ip_send_skb(struct net *net, struct sk_buff *skb);
229  int ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4);
230  void ip_flush_pending_frames(struct sock *sk);
231  struct sk_buff *ip_make_skb(struct sock *sk, struct flowi4 *fl4,
232  			    int getfrag(void *from, char *to, int offset,
233  					int len, int odd, struct sk_buff *skb),
234  			    void *from, int length, int transhdrlen,
235  			    struct ipcm_cookie *ipc, struct rtable **rtp,
236  			    struct inet_cork *cork, unsigned int flags);
237  
238  int ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl);
239  
ip_finish_skb(struct sock * sk,struct flowi4 * fl4)240  static inline struct sk_buff *ip_finish_skb(struct sock *sk, struct flowi4 *fl4)
241  {
242  	return __ip_make_skb(sk, fl4, &sk->sk_write_queue, &inet_sk(sk)->cork.base);
243  }
244  
get_rttos(struct ipcm_cookie * ipc,struct inet_sock * inet)245  static inline __u8 get_rttos(struct ipcm_cookie* ipc, struct inet_sock *inet)
246  {
247  	return (ipc->tos != -1) ? RT_TOS(ipc->tos) : RT_TOS(inet->tos);
248  }
249  
get_rtconn_flags(struct ipcm_cookie * ipc,struct sock * sk)250  static inline __u8 get_rtconn_flags(struct ipcm_cookie* ipc, struct sock* sk)
251  {
252  	return (ipc->tos != -1) ? RT_CONN_FLAGS_TOS(sk, ipc->tos) : RT_CONN_FLAGS(sk);
253  }
254  
255  /* datagram.c */
256  int __ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
257  int ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
258  
259  void ip4_datagram_release_cb(struct sock *sk);
260  
261  struct ip_reply_arg {
262  	struct kvec iov[1];
263  	int	    flags;
264  	__wsum 	    csum;
265  	int	    csumoffset; /* u16 offset of csum in iov[0].iov_base */
266  				/* -1 if not needed */
267  	int	    bound_dev_if;
268  	u8  	    tos;
269  	kuid_t	    uid;
270  };
271  
272  #define IP_REPLY_ARG_NOSRCCHECK 1
273  
ip_reply_arg_flowi_flags(const struct ip_reply_arg * arg)274  static inline __u8 ip_reply_arg_flowi_flags(const struct ip_reply_arg *arg)
275  {
276  	return (arg->flags & IP_REPLY_ARG_NOSRCCHECK) ? FLOWI_FLAG_ANYSRC : 0;
277  }
278  
279  void ip_send_unicast_reply(struct sock *sk, struct sk_buff *skb,
280  			   const struct ip_options *sopt,
281  			   __be32 daddr, __be32 saddr,
282  			   const struct ip_reply_arg *arg,
283  			   unsigned int len, u64 transmit_time);
284  
285  #define IP_INC_STATS(net, field)	SNMP_INC_STATS64((net)->mib.ip_statistics, field)
286  #define __IP_INC_STATS(net, field)	__SNMP_INC_STATS64((net)->mib.ip_statistics, field)
287  #define IP_ADD_STATS(net, field, val)	SNMP_ADD_STATS64((net)->mib.ip_statistics, field, val)
288  #define __IP_ADD_STATS(net, field, val) __SNMP_ADD_STATS64((net)->mib.ip_statistics, field, val)
289  #define IP_UPD_PO_STATS(net, field, val) SNMP_UPD_PO_STATS64((net)->mib.ip_statistics, field, val)
290  #define __IP_UPD_PO_STATS(net, field, val) __SNMP_UPD_PO_STATS64((net)->mib.ip_statistics, field, val)
291  #define NET_INC_STATS(net, field)	SNMP_INC_STATS((net)->mib.net_statistics, field)
292  #define __NET_INC_STATS(net, field)	__SNMP_INC_STATS((net)->mib.net_statistics, field)
293  #define NET_ADD_STATS(net, field, adnd)	SNMP_ADD_STATS((net)->mib.net_statistics, field, adnd)
294  #define __NET_ADD_STATS(net, field, adnd) __SNMP_ADD_STATS((net)->mib.net_statistics, field, adnd)
295  
snmp_get_cpu_field(void __percpu * mib,int cpu,int offt)296  static inline u64 snmp_get_cpu_field(void __percpu *mib, int cpu, int offt)
297  {
298  	return  *(((unsigned long *)per_cpu_ptr(mib, cpu)) + offt);
299  }
300  
301  unsigned long snmp_fold_field(void __percpu *mib, int offt);
302  #if BITS_PER_LONG==32
303  u64 snmp_get_cpu_field64(void __percpu *mib, int cpu, int offct,
304  			 size_t syncp_offset);
305  u64 snmp_fold_field64(void __percpu *mib, int offt, size_t sync_off);
306  #else
snmp_get_cpu_field64(void __percpu * mib,int cpu,int offct,size_t syncp_offset)307  static inline u64  snmp_get_cpu_field64(void __percpu *mib, int cpu, int offct,
308  					size_t syncp_offset)
309  {
310  	return snmp_get_cpu_field(mib, cpu, offct);
311  
312  }
313  
snmp_fold_field64(void __percpu * mib,int offt,size_t syncp_off)314  static inline u64 snmp_fold_field64(void __percpu *mib, int offt, size_t syncp_off)
315  {
316  	return snmp_fold_field(mib, offt);
317  }
318  #endif
319  
320  #define snmp_get_cpu_field64_batch(buff64, stats_list, mib_statistic, offset) \
321  { \
322  	int i, c; \
323  	for_each_possible_cpu(c) { \
324  		for (i = 0; stats_list[i].name; i++) \
325  			buff64[i] += snmp_get_cpu_field64( \
326  					mib_statistic, \
327  					c, stats_list[i].entry, \
328  					offset); \
329  	} \
330  }
331  
332  #define snmp_get_cpu_field_batch(buff, stats_list, mib_statistic) \
333  { \
334  	int i, c; \
335  	for_each_possible_cpu(c) { \
336  		for (i = 0; stats_list[i].name; i++) \
337  			buff[i] += snmp_get_cpu_field( \
338  						mib_statistic, \
339  						c, stats_list[i].entry); \
340  	} \
341  }
342  
343  void inet_get_local_port_range(const struct net *net, int *low, int *high);
344  void inet_sk_get_local_port_range(const struct sock *sk, int *low, int *high);
345  
346  #ifdef CONFIG_SYSCTL
inet_is_local_reserved_port(struct net * net,unsigned short port)347  static inline bool inet_is_local_reserved_port(struct net *net, unsigned short port)
348  {
349  	if (!net->ipv4.sysctl_local_reserved_ports)
350  		return false;
351  	return test_bit(port, net->ipv4.sysctl_local_reserved_ports);
352  }
353  
sysctl_dev_name_is_allowed(const char * name)354  static inline bool sysctl_dev_name_is_allowed(const char *name)
355  {
356  	return strcmp(name, "default") != 0  && strcmp(name, "all") != 0;
357  }
358  
inet_port_requires_bind_service(struct net * net,unsigned short port)359  static inline bool inet_port_requires_bind_service(struct net *net, unsigned short port)
360  {
361  	return port < READ_ONCE(net->ipv4.sysctl_ip_prot_sock);
362  }
363  
364  #else
inet_is_local_reserved_port(struct net * net,unsigned short port)365  static inline bool inet_is_local_reserved_port(struct net *net, unsigned short port)
366  {
367  	return false;
368  }
369  
inet_port_requires_bind_service(struct net * net,unsigned short port)370  static inline bool inet_port_requires_bind_service(struct net *net, unsigned short port)
371  {
372  	return port < PROT_SOCK;
373  }
374  #endif
375  
376  __be32 inet_current_timestamp(void);
377  
378  /* From inetpeer.c */
379  extern int inet_peer_threshold;
380  extern int inet_peer_minttl;
381  extern int inet_peer_maxttl;
382  
383  void ipfrag_init(void);
384  
385  void ip_static_sysctl_init(void);
386  
387  #define IP4_REPLY_MARK(net, mark) \
388  	(READ_ONCE((net)->ipv4.sysctl_fwmark_reflect) ? (mark) : 0)
389  
ip_is_fragment(const struct iphdr * iph)390  static inline bool ip_is_fragment(const struct iphdr *iph)
391  {
392  	return (iph->frag_off & htons(IP_MF | IP_OFFSET)) != 0;
393  }
394  
395  #ifdef CONFIG_INET
396  #include <net/dst.h>
397  
398  /* The function in 2.2 was invalid, producing wrong result for
399   * check=0xFEFF. It was noticed by Arthur Skawina _year_ ago. --ANK(000625) */
400  static inline
ip_decrease_ttl(struct iphdr * iph)401  int ip_decrease_ttl(struct iphdr *iph)
402  {
403  	u32 check = (__force u32)iph->check;
404  	check += (__force u32)htons(0x0100);
405  	iph->check = (__force __sum16)(check + (check>=0xFFFF));
406  	return --iph->ttl;
407  }
408  
ip_mtu_locked(const struct dst_entry * dst)409  static inline int ip_mtu_locked(const struct dst_entry *dst)
410  {
411  	const struct rtable *rt = (const struct rtable *)dst;
412  
413  	return rt->rt_mtu_locked || dst_metric_locked(dst, RTAX_MTU);
414  }
415  
416  static inline
ip_dont_fragment(const struct sock * sk,const struct dst_entry * dst)417  int ip_dont_fragment(const struct sock *sk, const struct dst_entry *dst)
418  {
419  	u8 pmtudisc = READ_ONCE(inet_sk(sk)->pmtudisc);
420  
421  	return  pmtudisc == IP_PMTUDISC_DO ||
422  		(pmtudisc == IP_PMTUDISC_WANT &&
423  		 !ip_mtu_locked(dst));
424  }
425  
ip_sk_accept_pmtu(const struct sock * sk)426  static inline bool ip_sk_accept_pmtu(const struct sock *sk)
427  {
428  	return inet_sk(sk)->pmtudisc != IP_PMTUDISC_INTERFACE &&
429  	       inet_sk(sk)->pmtudisc != IP_PMTUDISC_OMIT;
430  }
431  
ip_sk_use_pmtu(const struct sock * sk)432  static inline bool ip_sk_use_pmtu(const struct sock *sk)
433  {
434  	return inet_sk(sk)->pmtudisc < IP_PMTUDISC_PROBE;
435  }
436  
ip_sk_ignore_df(const struct sock * sk)437  static inline bool ip_sk_ignore_df(const struct sock *sk)
438  {
439  	return inet_sk(sk)->pmtudisc < IP_PMTUDISC_DO ||
440  	       inet_sk(sk)->pmtudisc == IP_PMTUDISC_OMIT;
441  }
442  
ip_dst_mtu_maybe_forward(const struct dst_entry * dst,bool forwarding)443  static inline unsigned int ip_dst_mtu_maybe_forward(const struct dst_entry *dst,
444  						    bool forwarding)
445  {
446  	const struct rtable *rt = container_of(dst, struct rtable, dst);
447  	struct net *net = dev_net(dst->dev);
448  	unsigned int mtu;
449  
450  	if (READ_ONCE(net->ipv4.sysctl_ip_fwd_use_pmtu) ||
451  	    ip_mtu_locked(dst) ||
452  	    !forwarding) {
453  		mtu = rt->rt_pmtu;
454  		if (mtu && time_before(jiffies, rt->dst.expires))
455  			goto out;
456  	}
457  
458  	/* 'forwarding = true' case should always honour route mtu */
459  	mtu = dst_metric_raw(dst, RTAX_MTU);
460  	if (mtu)
461  		goto out;
462  
463  	mtu = READ_ONCE(dst->dev->mtu);
464  
465  	if (unlikely(ip_mtu_locked(dst))) {
466  		if (rt->rt_uses_gateway && mtu > 576)
467  			mtu = 576;
468  	}
469  
470  out:
471  	mtu = min_t(unsigned int, mtu, IP_MAX_MTU);
472  
473  	return mtu - lwtunnel_headroom(dst->lwtstate, mtu);
474  }
475  
ip_skb_dst_mtu(struct sock * sk,const struct sk_buff * skb)476  static inline unsigned int ip_skb_dst_mtu(struct sock *sk,
477  					  const struct sk_buff *skb)
478  {
479  	unsigned int mtu;
480  
481  	if (!sk || !sk_fullsock(sk) || ip_sk_use_pmtu(sk)) {
482  		bool forwarding = IPCB(skb)->flags & IPSKB_FORWARDED;
483  
484  		return ip_dst_mtu_maybe_forward(skb_dst(skb), forwarding);
485  	}
486  
487  	mtu = min(READ_ONCE(skb_dst(skb)->dev->mtu), IP_MAX_MTU);
488  	return mtu - lwtunnel_headroom(skb_dst(skb)->lwtstate, mtu);
489  }
490  
491  struct dst_metrics *ip_fib_metrics_init(struct net *net, struct nlattr *fc_mx,
492  					int fc_mx_len,
493  					struct netlink_ext_ack *extack);
ip_fib_metrics_put(struct dst_metrics * fib_metrics)494  static inline void ip_fib_metrics_put(struct dst_metrics *fib_metrics)
495  {
496  	if (fib_metrics != &dst_default_metrics &&
497  	    refcount_dec_and_test(&fib_metrics->refcnt))
498  		kfree(fib_metrics);
499  }
500  
501  /* ipv4 and ipv6 both use refcounted metrics if it is not the default */
502  static inline
ip_dst_init_metrics(struct dst_entry * dst,struct dst_metrics * fib_metrics)503  void ip_dst_init_metrics(struct dst_entry *dst, struct dst_metrics *fib_metrics)
504  {
505  	dst_init_metrics(dst, fib_metrics->metrics, true);
506  
507  	if (fib_metrics != &dst_default_metrics) {
508  		dst->_metrics |= DST_METRICS_REFCOUNTED;
509  		refcount_inc(&fib_metrics->refcnt);
510  	}
511  }
512  
513  static inline
ip_dst_metrics_put(struct dst_entry * dst)514  void ip_dst_metrics_put(struct dst_entry *dst)
515  {
516  	struct dst_metrics *p = (struct dst_metrics *)DST_METRICS_PTR(dst);
517  
518  	if (p != &dst_default_metrics && refcount_dec_and_test(&p->refcnt))
519  		kfree(p);
520  }
521  
522  void __ip_select_ident(struct net *net, struct iphdr *iph, int segs);
523  
ip_select_ident_segs(struct net * net,struct sk_buff * skb,struct sock * sk,int segs)524  static inline void ip_select_ident_segs(struct net *net, struct sk_buff *skb,
525  					struct sock *sk, int segs)
526  {
527  	struct iphdr *iph = ip_hdr(skb);
528  
529  	/* We had many attacks based on IPID, use the private
530  	 * generator as much as we can.
531  	 */
532  	if (sk && inet_sk(sk)->inet_daddr) {
533  		iph->id = htons(inet_sk(sk)->inet_id);
534  		inet_sk(sk)->inet_id += segs;
535  		return;
536  	}
537  	if ((iph->frag_off & htons(IP_DF)) && !skb->ignore_df) {
538  		iph->id = 0;
539  	} else {
540  		/* Unfortunately we need the big hammer to get a suitable IPID */
541  		__ip_select_ident(net, iph, segs);
542  	}
543  }
544  
ip_select_ident(struct net * net,struct sk_buff * skb,struct sock * sk)545  static inline void ip_select_ident(struct net *net, struct sk_buff *skb,
546  				   struct sock *sk)
547  {
548  	ip_select_ident_segs(net, skb, sk, 1);
549  }
550  
inet_compute_pseudo(struct sk_buff * skb,int proto)551  static inline __wsum inet_compute_pseudo(struct sk_buff *skb, int proto)
552  {
553  	return csum_tcpudp_nofold(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
554  				  skb->len, proto, 0);
555  }
556  
557  /* copy IPv4 saddr & daddr to flow_keys, possibly using 64bit load/store
558   * Equivalent to :	flow->v4addrs.src = iph->saddr;
559   *			flow->v4addrs.dst = iph->daddr;
560   */
iph_to_flow_copy_v4addrs(struct flow_keys * flow,const struct iphdr * iph)561  static inline void iph_to_flow_copy_v4addrs(struct flow_keys *flow,
562  					    const struct iphdr *iph)
563  {
564  	BUILD_BUG_ON(offsetof(typeof(flow->addrs), v4addrs.dst) !=
565  		     offsetof(typeof(flow->addrs), v4addrs.src) +
566  			      sizeof(flow->addrs.v4addrs.src));
567  	memcpy(&flow->addrs.v4addrs, &iph->addrs, sizeof(flow->addrs.v4addrs));
568  	flow->control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
569  }
570  
571  /*
572   *	Map a multicast IP onto multicast MAC for type ethernet.
573   */
574  
ip_eth_mc_map(__be32 naddr,char * buf)575  static inline void ip_eth_mc_map(__be32 naddr, char *buf)
576  {
577  	__u32 addr=ntohl(naddr);
578  	buf[0]=0x01;
579  	buf[1]=0x00;
580  	buf[2]=0x5e;
581  	buf[5]=addr&0xFF;
582  	addr>>=8;
583  	buf[4]=addr&0xFF;
584  	addr>>=8;
585  	buf[3]=addr&0x7F;
586  }
587  
588  /*
589   *	Map a multicast IP onto multicast MAC for type IP-over-InfiniBand.
590   *	Leave P_Key as 0 to be filled in by driver.
591   */
592  
ip_ib_mc_map(__be32 naddr,const unsigned char * broadcast,char * buf)593  static inline void ip_ib_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
594  {
595  	__u32 addr;
596  	unsigned char scope = broadcast[5] & 0xF;
597  
598  	buf[0]  = 0;		/* Reserved */
599  	buf[1]  = 0xff;		/* Multicast QPN */
600  	buf[2]  = 0xff;
601  	buf[3]  = 0xff;
602  	addr    = ntohl(naddr);
603  	buf[4]  = 0xff;
604  	buf[5]  = 0x10 | scope;	/* scope from broadcast address */
605  	buf[6]  = 0x40;		/* IPv4 signature */
606  	buf[7]  = 0x1b;
607  	buf[8]  = broadcast[8];		/* P_Key */
608  	buf[9]  = broadcast[9];
609  	buf[10] = 0;
610  	buf[11] = 0;
611  	buf[12] = 0;
612  	buf[13] = 0;
613  	buf[14] = 0;
614  	buf[15] = 0;
615  	buf[19] = addr & 0xff;
616  	addr  >>= 8;
617  	buf[18] = addr & 0xff;
618  	addr  >>= 8;
619  	buf[17] = addr & 0xff;
620  	addr  >>= 8;
621  	buf[16] = addr & 0x0f;
622  }
623  
ip_ipgre_mc_map(__be32 naddr,const unsigned char * broadcast,char * buf)624  static inline void ip_ipgre_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
625  {
626  	if ((broadcast[0] | broadcast[1] | broadcast[2] | broadcast[3]) != 0)
627  		memcpy(buf, broadcast, 4);
628  	else
629  		memcpy(buf, &naddr, sizeof(naddr));
630  }
631  
632  #if IS_ENABLED(CONFIG_IPV6)
633  #include <linux/ipv6.h>
634  #endif
635  
inet_reset_saddr(struct sock * sk)636  static __inline__ void inet_reset_saddr(struct sock *sk)
637  {
638  	inet_sk(sk)->inet_rcv_saddr = inet_sk(sk)->inet_saddr = 0;
639  #if IS_ENABLED(CONFIG_IPV6)
640  	if (sk->sk_family == PF_INET6) {
641  		struct ipv6_pinfo *np = inet6_sk(sk);
642  
643  		memset(&np->saddr, 0, sizeof(np->saddr));
644  		memset(&sk->sk_v6_rcv_saddr, 0, sizeof(sk->sk_v6_rcv_saddr));
645  	}
646  #endif
647  }
648  
649  #endif
650  
ipv4_addr_hash(__be32 ip)651  static inline unsigned int ipv4_addr_hash(__be32 ip)
652  {
653  	return (__force unsigned int) ip;
654  }
655  
ipv4_portaddr_hash(const struct net * net,__be32 saddr,unsigned int port)656  static inline u32 ipv4_portaddr_hash(const struct net *net,
657  				     __be32 saddr,
658  				     unsigned int port)
659  {
660  	return jhash_1word((__force u32)saddr, net_hash_mix(net)) ^ port;
661  }
662  
663  bool ip_call_ra_chain(struct sk_buff *skb);
664  
665  /*
666   *	Functions provided by ip_fragment.c
667   */
668  
669  enum ip_defrag_users {
670  	IP_DEFRAG_LOCAL_DELIVER,
671  	IP_DEFRAG_CALL_RA_CHAIN,
672  	IP_DEFRAG_CONNTRACK_IN,
673  	__IP_DEFRAG_CONNTRACK_IN_END	= IP_DEFRAG_CONNTRACK_IN + USHRT_MAX,
674  	IP_DEFRAG_CONNTRACK_OUT,
675  	__IP_DEFRAG_CONNTRACK_OUT_END	= IP_DEFRAG_CONNTRACK_OUT + USHRT_MAX,
676  	IP_DEFRAG_CONNTRACK_BRIDGE_IN,
677  	__IP_DEFRAG_CONNTRACK_BRIDGE_IN = IP_DEFRAG_CONNTRACK_BRIDGE_IN + USHRT_MAX,
678  	IP_DEFRAG_VS_IN,
679  	IP_DEFRAG_VS_OUT,
680  	IP_DEFRAG_VS_FWD,
681  	IP_DEFRAG_AF_PACKET,
682  	IP_DEFRAG_MACVLAN,
683  };
684  
685  /* Return true if the value of 'user' is between 'lower_bond'
686   * and 'upper_bond' inclusively.
687   */
ip_defrag_user_in_between(u32 user,enum ip_defrag_users lower_bond,enum ip_defrag_users upper_bond)688  static inline bool ip_defrag_user_in_between(u32 user,
689  					     enum ip_defrag_users lower_bond,
690  					     enum ip_defrag_users upper_bond)
691  {
692  	return user >= lower_bond && user <= upper_bond;
693  }
694  
695  int ip_defrag(struct net *net, struct sk_buff *skb, u32 user);
696  #ifdef CONFIG_INET
697  struct sk_buff *ip_check_defrag(struct net *net, struct sk_buff *skb, u32 user);
698  #else
ip_check_defrag(struct net * net,struct sk_buff * skb,u32 user)699  static inline struct sk_buff *ip_check_defrag(struct net *net, struct sk_buff *skb, u32 user)
700  {
701  	return skb;
702  }
703  #endif
704  
705  /*
706   *	Functions provided by ip_forward.c
707   */
708  
709  int ip_forward(struct sk_buff *skb);
710  
711  /*
712   *	Functions provided by ip_options.c
713   */
714  
715  void ip_options_build(struct sk_buff *skb, struct ip_options *opt,
716  		      __be32 daddr, struct rtable *rt);
717  
718  int __ip_options_echo(struct net *net, struct ip_options *dopt,
719  		      struct sk_buff *skb, const struct ip_options *sopt);
ip_options_echo(struct net * net,struct ip_options * dopt,struct sk_buff * skb)720  static inline int ip_options_echo(struct net *net, struct ip_options *dopt,
721  				  struct sk_buff *skb)
722  {
723  	return __ip_options_echo(net, dopt, skb, &IPCB(skb)->opt);
724  }
725  
726  void ip_options_fragment(struct sk_buff *skb);
727  int __ip_options_compile(struct net *net, struct ip_options *opt,
728  			 struct sk_buff *skb, __be32 *info);
729  int ip_options_compile(struct net *net, struct ip_options *opt,
730  		       struct sk_buff *skb);
731  int ip_options_get(struct net *net, struct ip_options_rcu **optp,
732  		   sockptr_t data, int optlen);
733  void ip_options_undo(struct ip_options *opt);
734  void ip_forward_options(struct sk_buff *skb);
735  int ip_options_rcv_srr(struct sk_buff *skb, struct net_device *dev);
736  
737  /*
738   *	Functions provided by ip_sockglue.c
739   */
740  
741  void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb);
742  void ip_cmsg_recv_offset(struct msghdr *msg, struct sock *sk,
743  			 struct sk_buff *skb, int tlen, int offset);
744  int ip_cmsg_send(struct sock *sk, struct msghdr *msg,
745  		 struct ipcm_cookie *ipc, bool allow_ipv6);
746  DECLARE_STATIC_KEY_FALSE(ip4_min_ttl);
747  int do_ip_setsockopt(struct sock *sk, int level, int optname, sockptr_t optval,
748  		     unsigned int optlen);
749  int ip_setsockopt(struct sock *sk, int level, int optname, sockptr_t optval,
750  		  unsigned int optlen);
751  int do_ip_getsockopt(struct sock *sk, int level, int optname,
752  		     sockptr_t optval, sockptr_t optlen);
753  int ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
754  		  int __user *optlen);
755  int ip_ra_control(struct sock *sk, unsigned char on,
756  		  void (*destructor)(struct sock *));
757  
758  int ip_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len);
759  void ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err, __be16 port,
760  		   u32 info, u8 *payload);
761  void ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 dport,
762  		    u32 info);
763  
ip_cmsg_recv(struct msghdr * msg,struct sk_buff * skb)764  static inline void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb)
765  {
766  	ip_cmsg_recv_offset(msg, skb->sk, skb, 0, 0);
767  }
768  
769  bool icmp_global_allow(void);
770  extern int sysctl_icmp_msgs_per_sec;
771  extern int sysctl_icmp_msgs_burst;
772  
773  #ifdef CONFIG_PROC_FS
774  int ip_misc_proc_init(void);
775  #endif
776  
777  int rtm_getroute_parse_ip_proto(struct nlattr *attr, u8 *ip_proto, u8 family,
778  				struct netlink_ext_ack *extack);
779  
inetdev_valid_mtu(unsigned int mtu)780  static inline bool inetdev_valid_mtu(unsigned int mtu)
781  {
782  	return likely(mtu >= IPV4_MIN_MTU);
783  }
784  
785  void ip_sock_set_freebind(struct sock *sk);
786  int ip_sock_set_mtu_discover(struct sock *sk, int val);
787  void ip_sock_set_pktinfo(struct sock *sk);
788  void ip_sock_set_recverr(struct sock *sk);
789  void ip_sock_set_tos(struct sock *sk, int val);
790  void  __ip_sock_set_tos(struct sock *sk, int val);
791  
792  #endif	/* _IP_H */
793