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
63 u16 frag_max_size;
64};
65
66static inline bool ipv4_l3mdev_skb(u16 flags)
67{
68 return !!(flags & IPSKB_L3SLAVE);
69}
70
71static inline unsigned int ip_hdrlen(const struct sk_buff *skb)
72{
73 return ip_hdr(skb)->ihl * 4;
74}
75
76struct ipcm_cookie {
77 struct sockcm_cookie sockc;
78 __be32 addr;
79 int oif;
80 struct ip_options_rcu *opt;
81 __u8 protocol;
82 __u8 ttl;
83 __s16 tos;
84 __u16 gso_size;
85};
86
87static inline void ipcm_init(struct ipcm_cookie *ipcm)
88{
89 *ipcm = (struct ipcm_cookie) { .tos = -1 };
90}
91
92static inline void ipcm_init_sk(struct ipcm_cookie *ipcm,
93 const struct inet_sock *inet)
94{
95 *ipcm = (struct ipcm_cookie) {
96 .tos = READ_ONCE(inet->tos),
97 };
98
99 sockcm_init(sockc: &ipcm->sockc, sk: &inet->sk);
100
101 ipcm->oif = READ_ONCE(inet->sk.sk_bound_dev_if);
102 ipcm->addr = inet->inet_saddr;
103 ipcm->protocol = inet->inet_num;
104}
105
106#define IPCB(skb) ((struct inet_skb_parm*)((skb)->cb))
107#define PKTINFO_SKB_CB(skb) ((struct in_pktinfo *)((skb)->cb))
108
109/* return enslaved device index if relevant */
110static inline int inet_sdif(const struct sk_buff *skb)
111{
112#if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
113 if (skb && ipv4_l3mdev_skb(IPCB(skb)->flags))
114 return IPCB(skb)->iif;
115#endif
116 return 0;
117}
118
119/* Special input handler for packets caught by router alert option.
120 They are selected only by protocol field, and then processed likely
121 local ones; but only if someone wants them! Otherwise, router
122 not running rsvpd will kill RSVP.
123
124 It is user level problem, what it will make with them.
125 I have no idea, how it will masquearde or NAT them (it is joke, joke :-)),
126 but receiver should be enough clever f.e. to forward mtrace requests,
127 sent to multicast group to reach destination designated router.
128 */
129
130struct ip_ra_chain {
131 struct ip_ra_chain __rcu *next;
132 struct sock *sk;
133 union {
134 void (*destructor)(struct sock *);
135 struct sock *saved_sk;
136 };
137 struct rcu_head rcu;
138};
139
140/* IP flags. */
141#define IP_CE 0x8000 /* Flag: "Congestion" */
142#define IP_DF 0x4000 /* Flag: "Don't Fragment" */
143#define IP_MF 0x2000 /* Flag: "More Fragments" */
144#define IP_OFFSET 0x1FFF /* "Fragment Offset" part */
145
146#define IP_FRAG_TIME (30 * HZ) /* fragment lifetime */
147
148struct msghdr;
149struct net_device;
150struct packet_type;
151struct rtable;
152struct sockaddr;
153
154int igmp_mc_init(void);
155
156/*
157 * Functions provided by ip.c
158 */
159
160int ip_build_and_send_pkt(struct sk_buff *skb, const struct sock *sk,
161 __be32 saddr, __be32 daddr,
162 struct ip_options_rcu *opt, u8 tos);
163int ip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt,
164 struct net_device *orig_dev);
165void ip_list_rcv(struct list_head *head, struct packet_type *pt,
166 struct net_device *orig_dev);
167int ip_local_deliver(struct sk_buff *skb);
168void ip_protocol_deliver_rcu(struct net *net, struct sk_buff *skb, int proto);
169int ip_mr_input(struct sk_buff *skb);
170int ip_output(struct net *net, struct sock *sk, struct sk_buff *skb);
171int ip_mc_output(struct net *net, struct sock *sk, struct sk_buff *skb);
172int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
173 int (*output)(struct net *, struct sock *, struct sk_buff *));
174
175struct ip_fraglist_iter {
176 struct sk_buff *frag;
177 struct iphdr *iph;
178 int offset;
179 unsigned int hlen;
180};
181
182void ip_fraglist_init(struct sk_buff *skb, struct iphdr *iph,
183 unsigned int hlen, struct ip_fraglist_iter *iter);
184void ip_fraglist_prepare(struct sk_buff *skb, struct ip_fraglist_iter *iter);
185
186static inline struct sk_buff *ip_fraglist_next(struct ip_fraglist_iter *iter)
187{
188 struct sk_buff *skb = iter->frag;
189
190 iter->frag = skb->next;
191 skb_mark_not_on_list(skb);
192
193 return skb;
194}
195
196struct ip_frag_state {
197 bool DF;
198 unsigned int hlen;
199 unsigned int ll_rs;
200 unsigned int mtu;
201 unsigned int left;
202 int offset;
203 int ptr;
204 __be16 not_last_frag;
205};
206
207void ip_frag_init(struct sk_buff *skb, unsigned int hlen, unsigned int ll_rs,
208 unsigned int mtu, bool DF, struct ip_frag_state *state);
209struct sk_buff *ip_frag_next(struct sk_buff *skb,
210 struct ip_frag_state *state);
211
212void ip_send_check(struct iphdr *ip);
213int __ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb);
214int ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb);
215
216int __ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl,
217 __u8 tos);
218void ip_init(void);
219int ip_append_data(struct sock *sk, struct flowi4 *fl4,
220 int getfrag(void *from, char *to, int offset, int len,
221 int odd, struct sk_buff *skb),
222 void *from, int len, int protolen,
223 struct ipcm_cookie *ipc,
224 struct rtable **rt,
225 unsigned int flags);
226int ip_generic_getfrag(void *from, char *to, int offset, int len, int odd,
227 struct sk_buff *skb);
228struct sk_buff *__ip_make_skb(struct sock *sk, struct flowi4 *fl4,
229 struct sk_buff_head *queue,
230 struct inet_cork *cork);
231int ip_send_skb(struct net *net, struct sk_buff *skb);
232int ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4);
233void ip_flush_pending_frames(struct sock *sk);
234struct sk_buff *ip_make_skb(struct sock *sk, struct flowi4 *fl4,
235 int getfrag(void *from, char *to, int offset,
236 int len, int odd, struct sk_buff *skb),
237 void *from, int length, int transhdrlen,
238 struct ipcm_cookie *ipc, struct rtable **rtp,
239 struct inet_cork *cork, unsigned int flags);
240
241int ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl);
242
243static inline struct sk_buff *ip_finish_skb(struct sock *sk, struct flowi4 *fl4)
244{
245 return __ip_make_skb(sk, fl4, queue: &sk->sk_write_queue, cork: &inet_sk(sk)->cork.base);
246}
247
248/* Get the route scope that should be used when sending a packet. */
249static inline u8 ip_sendmsg_scope(const struct inet_sock *inet,
250 const struct ipcm_cookie *ipc,
251 const struct msghdr *msg)
252{
253 if (sock_flag(sk: &inet->sk, flag: SOCK_LOCALROUTE) ||
254 msg->msg_flags & MSG_DONTROUTE ||
255 (ipc->opt && ipc->opt->opt.is_strictroute))
256 return RT_SCOPE_LINK;
257
258 return RT_SCOPE_UNIVERSE;
259}
260
261/* datagram.c */
262int __ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
263int ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
264
265void ip4_datagram_release_cb(struct sock *sk);
266
267struct ip_reply_arg {
268 struct kvec iov[1];
269 int flags;
270 __wsum csum;
271 int csumoffset; /* u16 offset of csum in iov[0].iov_base */
272 /* -1 if not needed */
273 int bound_dev_if;
274 u8 tos;
275 kuid_t uid;
276};
277
278#define IP_REPLY_ARG_NOSRCCHECK 1
279
280static inline __u8 ip_reply_arg_flowi_flags(const struct ip_reply_arg *arg)
281{
282 return (arg->flags & IP_REPLY_ARG_NOSRCCHECK) ? FLOWI_FLAG_ANYSRC : 0;
283}
284
285void ip_send_unicast_reply(struct sock *sk, const struct sock *orig_sk,
286 struct sk_buff *skb,
287 const struct ip_options *sopt,
288 __be32 daddr, __be32 saddr,
289 const struct ip_reply_arg *arg,
290 unsigned int len, u64 transmit_time, u32 txhash);
291
292#define IP_INC_STATS(net, field) SNMP_INC_STATS64((net)->mib.ip_statistics, field)
293#define __IP_INC_STATS(net, field) __SNMP_INC_STATS64((net)->mib.ip_statistics, field)
294#define IP_ADD_STATS(net, field, val) SNMP_ADD_STATS64((net)->mib.ip_statistics, field, val)
295#define __IP_ADD_STATS(net, field, val) __SNMP_ADD_STATS64((net)->mib.ip_statistics, field, val)
296#define IP_UPD_PO_STATS(net, field, val) SNMP_UPD_PO_STATS64((net)->mib.ip_statistics, field, val)
297#define __IP_UPD_PO_STATS(net, field, val) __SNMP_UPD_PO_STATS64((net)->mib.ip_statistics, field, val)
298#define NET_INC_STATS(net, field) SNMP_INC_STATS((net)->mib.net_statistics, field)
299#define __NET_INC_STATS(net, field) __SNMP_INC_STATS((net)->mib.net_statistics, field)
300#define NET_ADD_STATS(net, field, adnd) SNMP_ADD_STATS((net)->mib.net_statistics, field, adnd)
301#define __NET_ADD_STATS(net, field, adnd) __SNMP_ADD_STATS((net)->mib.net_statistics, field, adnd)
302
303static inline u64 snmp_get_cpu_field(void __percpu *mib, int cpu, int offt)
304{
305 return *(((unsigned long *)per_cpu_ptr(mib, cpu)) + offt);
306}
307
308unsigned long snmp_fold_field(void __percpu *mib, int offt);
309#if BITS_PER_LONG==32
310u64 snmp_get_cpu_field64(void __percpu *mib, int cpu, int offct,
311 size_t syncp_offset);
312u64 snmp_fold_field64(void __percpu *mib, int offt, size_t sync_off);
313#else
314static inline u64 snmp_get_cpu_field64(void __percpu *mib, int cpu, int offct,
315 size_t syncp_offset)
316{
317 return snmp_get_cpu_field(mib, cpu, offt: offct);
318
319}
320
321static inline u64 snmp_fold_field64(void __percpu *mib, int offt, size_t syncp_off)
322{
323 return snmp_fold_field(mib, offt);
324}
325#endif
326
327#define snmp_get_cpu_field64_batch(buff64, stats_list, mib_statistic, offset) \
328{ \
329 int i, c; \
330 for_each_possible_cpu(c) { \
331 for (i = 0; stats_list[i].name; i++) \
332 buff64[i] += snmp_get_cpu_field64( \
333 mib_statistic, \
334 c, stats_list[i].entry, \
335 offset); \
336 } \
337}
338
339#define snmp_get_cpu_field_batch(buff, stats_list, mib_statistic) \
340{ \
341 int i, c; \
342 for_each_possible_cpu(c) { \
343 for (i = 0; stats_list[i].name; i++) \
344 buff[i] += snmp_get_cpu_field( \
345 mib_statistic, \
346 c, stats_list[i].entry); \
347 } \
348}
349
350static inline void inet_get_local_port_range(const struct net *net, int *low, int *high)
351{
352 u32 range = READ_ONCE(net->ipv4.ip_local_ports.range);
353
354 *low = range & 0xffff;
355 *high = range >> 16;
356}
357bool inet_sk_get_local_port_range(const struct sock *sk, int *low, int *high);
358
359#ifdef CONFIG_SYSCTL
360static inline bool inet_is_local_reserved_port(const struct net *net, unsigned short port)
361{
362 if (!net->ipv4.sysctl_local_reserved_ports)
363 return false;
364 return test_bit(port, net->ipv4.sysctl_local_reserved_ports);
365}
366
367static inline bool sysctl_dev_name_is_allowed(const char *name)
368{
369 return strcmp(name, "default") != 0 && strcmp(name, "all") != 0;
370}
371
372static inline bool inet_port_requires_bind_service(struct net *net, unsigned short port)
373{
374 return port < READ_ONCE(net->ipv4.sysctl_ip_prot_sock);
375}
376
377#else
378static inline bool inet_is_local_reserved_port(struct net *net, unsigned short port)
379{
380 return false;
381}
382
383static inline bool inet_port_requires_bind_service(struct net *net, unsigned short port)
384{
385 return port < PROT_SOCK;
386}
387#endif
388
389__be32 inet_current_timestamp(void);
390
391/* From inetpeer.c */
392extern int inet_peer_threshold;
393extern int inet_peer_minttl;
394extern int inet_peer_maxttl;
395
396void ipfrag_init(void);
397
398void ip_static_sysctl_init(void);
399
400#define IP4_REPLY_MARK(net, mark) \
401 (READ_ONCE((net)->ipv4.sysctl_fwmark_reflect) ? (mark) : 0)
402
403static inline bool ip_is_fragment(const struct iphdr *iph)
404{
405 return (iph->frag_off & htons(IP_MF | IP_OFFSET)) != 0;
406}
407
408#ifdef CONFIG_INET
409#include <net/dst.h>
410
411/* The function in 2.2 was invalid, producing wrong result for
412 * check=0xFEFF. It was noticed by Arthur Skawina _year_ ago. --ANK(000625) */
413static inline
414int ip_decrease_ttl(struct iphdr *iph)
415{
416 u32 check = (__force u32)iph->check;
417 check += (__force u32)htons(0x0100);
418 iph->check = (__force __sum16)(check + (check>=0xFFFF));
419 return --iph->ttl;
420}
421
422static inline dscp_t ip4h_dscp(const struct iphdr *ip4h)
423{
424 return inet_dsfield_to_dscp(dsfield: ip4h->tos);
425}
426
427static inline int ip_mtu_locked(const struct dst_entry *dst)
428{
429 const struct rtable *rt = dst_rtable(dst);
430
431 return rt->rt_mtu_locked || dst_metric_locked(dst, RTAX_MTU);
432}
433
434static inline
435int ip_dont_fragment(const struct sock *sk, const struct dst_entry *dst)
436{
437 u8 pmtudisc = READ_ONCE(inet_sk(sk)->pmtudisc);
438
439 return pmtudisc == IP_PMTUDISC_DO ||
440 (pmtudisc == IP_PMTUDISC_WANT &&
441 !ip_mtu_locked(dst));
442}
443
444static inline bool ip_sk_accept_pmtu(const struct sock *sk)
445{
446 u8 pmtudisc = READ_ONCE(inet_sk(sk)->pmtudisc);
447
448 return pmtudisc != IP_PMTUDISC_INTERFACE &&
449 pmtudisc != IP_PMTUDISC_OMIT;
450}
451
452static inline bool ip_sk_use_pmtu(const struct sock *sk)
453{
454 return READ_ONCE(inet_sk(sk)->pmtudisc) < IP_PMTUDISC_PROBE;
455}
456
457static inline bool ip_sk_ignore_df(const struct sock *sk)
458{
459 u8 pmtudisc = READ_ONCE(inet_sk(sk)->pmtudisc);
460
461 return pmtudisc < IP_PMTUDISC_DO || pmtudisc == IP_PMTUDISC_OMIT;
462}
463
464static inline unsigned int ip_dst_mtu_maybe_forward(const struct dst_entry *dst,
465 bool forwarding)
466{
467 const struct rtable *rt = dst_rtable(dst);
468 unsigned int mtu, res;
469 struct net *net;
470
471 rcu_read_lock();
472
473 net = dev_net_rcu(dev: dst->dev);
474 if (READ_ONCE(net->ipv4.sysctl_ip_fwd_use_pmtu) ||
475 ip_mtu_locked(dst) ||
476 !forwarding) {
477 mtu = rt->rt_pmtu;
478 if (mtu && time_before(jiffies, rt->dst.expires))
479 goto out;
480 }
481
482 /* 'forwarding = true' case should always honour route mtu */
483 mtu = dst_metric_raw(dst, RTAX_MTU);
484 if (mtu)
485 goto out;
486
487 mtu = READ_ONCE(dst->dev->mtu);
488
489 if (unlikely(ip_mtu_locked(dst))) {
490 if (rt->rt_uses_gateway && mtu > 576)
491 mtu = 576;
492 }
493
494out:
495 mtu = min_t(unsigned int, mtu, IP_MAX_MTU);
496
497 res = mtu - lwtunnel_headroom(lwtstate: dst->lwtstate, mtu);
498
499 rcu_read_unlock();
500
501 return res;
502}
503
504static inline unsigned int ip_skb_dst_mtu(struct sock *sk,
505 const struct sk_buff *skb)
506{
507 unsigned int mtu;
508
509 if (!sk || !sk_fullsock(sk) || ip_sk_use_pmtu(sk)) {
510 bool forwarding = IPCB(skb)->flags & IPSKB_FORWARDED;
511
512 return ip_dst_mtu_maybe_forward(dst: skb_dst(skb), forwarding);
513 }
514
515 mtu = min(READ_ONCE(skb_dst(skb)->dev->mtu), IP_MAX_MTU);
516 return mtu - lwtunnel_headroom(lwtstate: skb_dst(skb)->lwtstate, mtu);
517}
518
519struct dst_metrics *ip_fib_metrics_init(struct nlattr *fc_mx, int fc_mx_len,
520 struct netlink_ext_ack *extack);
521static inline void ip_fib_metrics_put(struct dst_metrics *fib_metrics)
522{
523 if (fib_metrics != &dst_default_metrics &&
524 refcount_dec_and_test(r: &fib_metrics->refcnt))
525 kfree(objp: fib_metrics);
526}
527
528/* ipv4 and ipv6 both use refcounted metrics if it is not the default */
529static inline
530void ip_dst_init_metrics(struct dst_entry *dst, struct dst_metrics *fib_metrics)
531{
532 dst_init_metrics(dst, src_metrics: fib_metrics->metrics, read_only: true);
533
534 if (fib_metrics != &dst_default_metrics) {
535 dst->_metrics |= DST_METRICS_REFCOUNTED;
536 refcount_inc(r: &fib_metrics->refcnt);
537 }
538}
539
540static inline
541void ip_dst_metrics_put(struct dst_entry *dst)
542{
543 struct dst_metrics *p = (struct dst_metrics *)DST_METRICS_PTR(dst);
544
545 if (p != &dst_default_metrics && refcount_dec_and_test(r: &p->refcnt))
546 kfree(objp: p);
547}
548
549void __ip_select_ident(struct net *net, struct iphdr *iph, int segs);
550
551static inline void ip_select_ident_segs(struct net *net, struct sk_buff *skb,
552 struct sock *sk, int segs)
553{
554 struct iphdr *iph = ip_hdr(skb);
555
556 /* We had many attacks based on IPID, use the private
557 * generator as much as we can.
558 */
559 if (sk && inet_sk(sk)->inet_daddr) {
560 int val;
561
562 /* avoid atomic operations for TCP,
563 * as we hold socket lock at this point.
564 */
565 if (sk_is_tcp(sk)) {
566 sock_owned_by_me(sk);
567 val = atomic_read(v: &inet_sk(sk)->inet_id);
568 atomic_set(v: &inet_sk(sk)->inet_id, i: val + segs);
569 } else {
570 val = atomic_add_return(i: segs, v: &inet_sk(sk)->inet_id);
571 }
572 iph->id = htons(val);
573 return;
574 }
575 if ((iph->frag_off & htons(IP_DF)) && !skb->ignore_df) {
576 iph->id = 0;
577 } else {
578 /* Unfortunately we need the big hammer to get a suitable IPID */
579 __ip_select_ident(net, iph, segs);
580 }
581}
582
583static inline void ip_select_ident(struct net *net, struct sk_buff *skb,
584 struct sock *sk)
585{
586 ip_select_ident_segs(net, skb, sk, segs: 1);
587}
588
589static inline __wsum inet_compute_pseudo(struct sk_buff *skb, int proto)
590{
591 return csum_tcpudp_nofold(saddr: ip_hdr(skb)->saddr, daddr: ip_hdr(skb)->daddr,
592 len: skb->len, proto, sum: 0);
593}
594
595/* copy IPv4 saddr & daddr to flow_keys, possibly using 64bit load/store
596 * Equivalent to : flow->v4addrs.src = iph->saddr;
597 * flow->v4addrs.dst = iph->daddr;
598 */
599static inline void iph_to_flow_copy_v4addrs(struct flow_keys *flow,
600 const struct iphdr *iph)
601{
602 BUILD_BUG_ON(offsetof(typeof(flow->addrs), v4addrs.dst) !=
603 offsetof(typeof(flow->addrs), v4addrs.src) +
604 sizeof(flow->addrs.v4addrs.src));
605 memcpy(&flow->addrs.v4addrs, &iph->addrs, sizeof(flow->addrs.v4addrs));
606 flow->control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
607}
608
609/*
610 * Map a multicast IP onto multicast MAC for type ethernet.
611 */
612
613static inline void ip_eth_mc_map(__be32 naddr, char *buf)
614{
615 __u32 addr=ntohl(naddr);
616 buf[0]=0x01;
617 buf[1]=0x00;
618 buf[2]=0x5e;
619 buf[5]=addr&0xFF;
620 addr>>=8;
621 buf[4]=addr&0xFF;
622 addr>>=8;
623 buf[3]=addr&0x7F;
624}
625
626/*
627 * Map a multicast IP onto multicast MAC for type IP-over-InfiniBand.
628 * Leave P_Key as 0 to be filled in by driver.
629 */
630
631static inline void ip_ib_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
632{
633 __u32 addr;
634 unsigned char scope = broadcast[5] & 0xF;
635
636 buf[0] = 0; /* Reserved */
637 buf[1] = 0xff; /* Multicast QPN */
638 buf[2] = 0xff;
639 buf[3] = 0xff;
640 addr = ntohl(naddr);
641 buf[4] = 0xff;
642 buf[5] = 0x10 | scope; /* scope from broadcast address */
643 buf[6] = 0x40; /* IPv4 signature */
644 buf[7] = 0x1b;
645 buf[8] = broadcast[8]; /* P_Key */
646 buf[9] = broadcast[9];
647 buf[10] = 0;
648 buf[11] = 0;
649 buf[12] = 0;
650 buf[13] = 0;
651 buf[14] = 0;
652 buf[15] = 0;
653 buf[19] = addr & 0xff;
654 addr >>= 8;
655 buf[18] = addr & 0xff;
656 addr >>= 8;
657 buf[17] = addr & 0xff;
658 addr >>= 8;
659 buf[16] = addr & 0x0f;
660}
661
662static inline void ip_ipgre_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
663{
664 if ((broadcast[0] | broadcast[1] | broadcast[2] | broadcast[3]) != 0)
665 memcpy(buf, broadcast, 4);
666 else
667 memcpy(buf, &naddr, sizeof(naddr));
668}
669
670#if IS_ENABLED(CONFIG_IPV6)
671#include <linux/ipv6.h>
672#endif
673
674static __inline__ void inet_reset_saddr(struct sock *sk)
675{
676 inet_sk(sk)->inet_rcv_saddr = inet_sk(sk)->inet_saddr = 0;
677#if IS_ENABLED(CONFIG_IPV6)
678 if (sk->sk_family == PF_INET6) {
679 struct ipv6_pinfo *np = inet6_sk(sk: sk);
680
681 memset(&np->saddr, 0, sizeof(np->saddr));
682 memset(&sk->sk_v6_rcv_saddr, 0, sizeof(sk->sk_v6_rcv_saddr));
683 }
684#endif
685}
686
687#endif
688
689#if IS_MODULE(CONFIG_IPV6)
690#define EXPORT_IPV6_MOD(X) EXPORT_SYMBOL(X)
691#define EXPORT_IPV6_MOD_GPL(X) EXPORT_SYMBOL_GPL(X)
692#else
693#define EXPORT_IPV6_MOD(X)
694#define EXPORT_IPV6_MOD_GPL(X)
695#endif
696
697static inline unsigned int ipv4_addr_hash(__be32 ip)
698{
699 return (__force unsigned int) ip;
700}
701
702static inline u32 __ipv4_addr_hash(const __be32 ip, const u32 initval)
703{
704 return jhash_1word(a: (__force u32)ip, initval);
705}
706
707static inline u32 ipv4_portaddr_hash(const struct net *net,
708 __be32 saddr,
709 unsigned int port)
710{
711 return jhash_1word(a: (__force u32)saddr, initval: net_hash_mix(net)) ^ port;
712}
713
714bool ip_call_ra_chain(struct sk_buff *skb);
715
716/*
717 * Functions provided by ip_fragment.c
718 */
719
720enum ip_defrag_users {
721 IP_DEFRAG_LOCAL_DELIVER,
722 IP_DEFRAG_CALL_RA_CHAIN,
723 IP_DEFRAG_CONNTRACK_IN,
724 __IP_DEFRAG_CONNTRACK_IN_END = IP_DEFRAG_CONNTRACK_IN + USHRT_MAX,
725 IP_DEFRAG_CONNTRACK_OUT,
726 __IP_DEFRAG_CONNTRACK_OUT_END = IP_DEFRAG_CONNTRACK_OUT + USHRT_MAX,
727 IP_DEFRAG_CONNTRACK_BRIDGE_IN,
728 __IP_DEFRAG_CONNTRACK_BRIDGE_IN = IP_DEFRAG_CONNTRACK_BRIDGE_IN + USHRT_MAX,
729 IP_DEFRAG_VS_IN,
730 IP_DEFRAG_VS_OUT,
731 IP_DEFRAG_VS_FWD,
732 IP_DEFRAG_AF_PACKET,
733 IP_DEFRAG_MACVLAN,
734};
735
736/* Return true if the value of 'user' is between 'lower_bond'
737 * and 'upper_bond' inclusively.
738 */
739static inline bool ip_defrag_user_in_between(u32 user,
740 enum ip_defrag_users lower_bond,
741 enum ip_defrag_users upper_bond)
742{
743 return user >= lower_bond && user <= upper_bond;
744}
745
746int ip_defrag(struct net *net, struct sk_buff *skb, u32 user);
747#ifdef CONFIG_INET
748struct sk_buff *ip_check_defrag(struct net *net, struct sk_buff *skb, u32 user);
749#else
750static inline struct sk_buff *ip_check_defrag(struct net *net, struct sk_buff *skb, u32 user)
751{
752 return skb;
753}
754#endif
755
756/*
757 * Functions provided by ip_forward.c
758 */
759
760int ip_forward(struct sk_buff *skb);
761
762/*
763 * Functions provided by ip_options.c
764 */
765
766void ip_options_build(struct sk_buff *skb, struct ip_options *opt,
767 __be32 daddr, struct rtable *rt);
768
769int __ip_options_echo(struct net *net, struct ip_options *dopt,
770 struct sk_buff *skb, const struct ip_options *sopt);
771static inline int ip_options_echo(struct net *net, struct ip_options *dopt,
772 struct sk_buff *skb)
773{
774 return __ip_options_echo(net, dopt, skb, sopt: &IPCB(skb)->opt);
775}
776
777void ip_options_fragment(struct sk_buff *skb);
778int __ip_options_compile(struct net *net, struct ip_options *opt,
779 struct sk_buff *skb, __be32 *info);
780int ip_options_compile(struct net *net, struct ip_options *opt,
781 struct sk_buff *skb);
782int ip_options_get(struct net *net, struct ip_options_rcu **optp,
783 sockptr_t data, int optlen);
784void ip_options_undo(struct ip_options *opt);
785void ip_forward_options(struct sk_buff *skb);
786int ip_options_rcv_srr(struct sk_buff *skb, struct net_device *dev);
787
788/*
789 * Functions provided by ip_sockglue.c
790 */
791
792void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb, bool drop_dst);
793void ip_cmsg_recv_offset(struct msghdr *msg, struct sock *sk,
794 struct sk_buff *skb, int tlen, int offset);
795int ip_cmsg_send(struct sock *sk, struct msghdr *msg,
796 struct ipcm_cookie *ipc, bool allow_ipv6);
797DECLARE_STATIC_KEY_FALSE(ip4_min_ttl);
798int do_ip_setsockopt(struct sock *sk, int level, int optname, sockptr_t optval,
799 unsigned int optlen);
800int ip_setsockopt(struct sock *sk, int level, int optname, sockptr_t optval,
801 unsigned int optlen);
802int do_ip_getsockopt(struct sock *sk, int level, int optname,
803 sockptr_t optval, sockptr_t optlen);
804int ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
805 int __user *optlen);
806int ip_ra_control(struct sock *sk, unsigned char on,
807 void (*destructor)(struct sock *));
808
809int ip_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len);
810void ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err, __be16 port,
811 u32 info, u8 *payload);
812void ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 dport,
813 u32 info);
814
815static inline void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb)
816{
817 ip_cmsg_recv_offset(msg, sk: skb->sk, skb, tlen: 0, offset: 0);
818}
819
820bool icmp_global_allow(struct net *net);
821void icmp_global_consume(struct net *net);
822
823#ifdef CONFIG_PROC_FS
824int ip_misc_proc_init(void);
825#endif
826
827int rtm_getroute_parse_ip_proto(struct nlattr *attr, u8 *ip_proto, u8 family,
828 struct netlink_ext_ack *extack);
829
830static inline bool inetdev_valid_mtu(unsigned int mtu)
831{
832 return likely(mtu >= IPV4_MIN_MTU);
833}
834
835void ip_sock_set_freebind(struct sock *sk);
836int ip_sock_set_mtu_discover(struct sock *sk, int val);
837void ip_sock_set_pktinfo(struct sock *sk);
838void ip_sock_set_recverr(struct sock *sk);
839void ip_sock_set_tos(struct sock *sk, int val);
840void __ip_sock_set_tos(struct sock *sk, int val);
841
842#endif /* _IP_H */
843

source code of linux/include/net/ip.h