linux/include/net/ip.h
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   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
  27#include <net/inet_sock.h>
  28#include <net/route.h>
  29#include <net/snmp.h>
  30#include <net/flow.h>
  31#include <net/flow_dissector.h>
  32#include <net/netns/hash.h>
  33
  34#define IPV4_MAX_PMTU           65535U          /* RFC 2675, Section 5.1 */
  35#define IPV4_MIN_MTU            68                      /* RFC 791 */
  36
  37extern unsigned int sysctl_fib_sync_mem;
  38extern unsigned int sysctl_fib_sync_mem_min;
  39extern unsigned int sysctl_fib_sync_mem_max;
  40
  41struct sock;
  42
  43struct inet_skb_parm {
  44        int                     iif;
  45        struct ip_options       opt;            /* Compiled IP options          */
  46        u16                     flags;
  47
  48#define IPSKB_FORWARDED         BIT(0)
  49#define IPSKB_XFRM_TUNNEL_SIZE  BIT(1)
  50#define IPSKB_XFRM_TRANSFORMED  BIT(2)
  51#define IPSKB_FRAG_COMPLETE     BIT(3)
  52#define IPSKB_REROUTED          BIT(4)
  53#define IPSKB_DOREDIRECT        BIT(5)
  54#define IPSKB_FRAG_PMTU         BIT(6)
  55#define IPSKB_L3SLAVE           BIT(7)
  56
  57        u16                     frag_max_size;
  58};
  59
  60static inline bool ipv4_l3mdev_skb(u16 flags)
  61{
  62        return !!(flags & IPSKB_L3SLAVE);
  63}
  64
  65static inline unsigned int ip_hdrlen(const struct sk_buff *skb)
  66{
  67        return ip_hdr(skb)->ihl * 4;
  68}
  69
  70struct ipcm_cookie {
  71        struct sockcm_cookie    sockc;
  72        __be32                  addr;
  73        int                     oif;
  74        struct ip_options_rcu   *opt;
  75        __u8                    ttl;
  76        __s16                   tos;
  77        char                    priority;
  78        __u16                   gso_size;
  79};
  80
  81static inline void ipcm_init(struct ipcm_cookie *ipcm)
  82{
  83        *ipcm = (struct ipcm_cookie) { .tos = -1 };
  84}
  85
  86static inline void ipcm_init_sk(struct ipcm_cookie *ipcm,
  87                                const struct inet_sock *inet)
  88{
  89        ipcm_init(ipcm);
  90
  91        ipcm->sockc.mark = inet->sk.sk_mark;
  92        ipcm->sockc.tsflags = inet->sk.sk_tsflags;
  93        ipcm->oif = inet->sk.sk_bound_dev_if;
  94        ipcm->addr = inet->inet_saddr;
  95}
  96
  97#define IPCB(skb) ((struct inet_skb_parm*)((skb)->cb))
  98#define PKTINFO_SKB_CB(skb) ((struct in_pktinfo *)((skb)->cb))
  99
 100/* return enslaved device index if relevant */
 101static inline int inet_sdif(struct sk_buff *skb)
 102{
 103#if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
 104        if (skb && ipv4_l3mdev_skb(IPCB(skb)->flags))
 105                return IPCB(skb)->iif;
 106#endif
 107        return 0;
 108}
 109
 110/* Special input handler for packets caught by router alert option.
 111   They are selected only by protocol field, and then processed likely
 112   local ones; but only if someone wants them! Otherwise, router
 113   not running rsvpd will kill RSVP.
 114
 115   It is user level problem, what it will make with them.
 116   I have no idea, how it will masquearde or NAT them (it is joke, joke :-)),
 117   but receiver should be enough clever f.e. to forward mtrace requests,
 118   sent to multicast group to reach destination designated router.
 119 */
 120
 121struct ip_ra_chain {
 122        struct ip_ra_chain __rcu *next;
 123        struct sock             *sk;
 124        union {
 125                void                    (*destructor)(struct sock *);
 126                struct sock             *saved_sk;
 127        };
 128        struct rcu_head         rcu;
 129};
 130
 131/* IP flags. */
 132#define IP_CE           0x8000          /* Flag: "Congestion"           */
 133#define IP_DF           0x4000          /* Flag: "Don't Fragment"       */
 134#define IP_MF           0x2000          /* Flag: "More Fragments"       */
 135#define IP_OFFSET       0x1FFF          /* "Fragment Offset" part       */
 136
 137#define IP_FRAG_TIME    (30 * HZ)               /* fragment lifetime    */
 138
 139struct msghdr;
 140struct net_device;
 141struct packet_type;
 142struct rtable;
 143struct sockaddr;
 144
 145int igmp_mc_init(void);
 146
 147/*
 148 *      Functions provided by ip.c
 149 */
 150
 151int ip_build_and_send_pkt(struct sk_buff *skb, const struct sock *sk,
 152                          __be32 saddr, __be32 daddr,
 153                          struct ip_options_rcu *opt);
 154int ip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt,
 155           struct net_device *orig_dev);
 156void ip_list_rcv(struct list_head *head, struct packet_type *pt,
 157                 struct net_device *orig_dev);
 158int ip_local_deliver(struct sk_buff *skb);
 159void ip_protocol_deliver_rcu(struct net *net, struct sk_buff *skb, int proto);
 160int ip_mr_input(struct sk_buff *skb);
 161int ip_output(struct net *net, struct sock *sk, struct sk_buff *skb);
 162int ip_mc_output(struct net *net, struct sock *sk, struct sk_buff *skb);
 163int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
 164                   int (*output)(struct net *, struct sock *, struct sk_buff *));
 165
 166struct ip_fraglist_iter {
 167        struct sk_buff  *frag;
 168        struct iphdr    *iph;
 169        int             offset;
 170        unsigned int    hlen;
 171};
 172
 173void ip_fraglist_init(struct sk_buff *skb, struct iphdr *iph,
 174                      unsigned int hlen, struct ip_fraglist_iter *iter);
 175void ip_fraglist_prepare(struct sk_buff *skb, struct ip_fraglist_iter *iter);
 176
 177static inline struct sk_buff *ip_fraglist_next(struct ip_fraglist_iter *iter)
 178{
 179        struct sk_buff *skb = iter->frag;
 180
 181        iter->frag = skb->next;
 182        skb_mark_not_on_list(skb);
 183
 184        return skb;
 185}
 186
 187struct ip_frag_state {
 188        bool            DF;
 189        unsigned int    hlen;
 190        unsigned int    ll_rs;
 191        unsigned int    mtu;
 192        unsigned int    left;
 193        int             offset;
 194        int             ptr;
 195        __be16          not_last_frag;
 196};
 197
 198void ip_frag_init(struct sk_buff *skb, unsigned int hlen, unsigned int ll_rs,
 199                  unsigned int mtu, bool DF, struct ip_frag_state *state);
 200struct sk_buff *ip_frag_next(struct sk_buff *skb,
 201                             struct ip_frag_state *state);
 202
 203void ip_send_check(struct iphdr *ip);
 204int __ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb);
 205int ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb);
 206
 207int __ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl,
 208                    __u8 tos);
 209void ip_init(void);
 210int ip_append_data(struct sock *sk, struct flowi4 *fl4,
 211                   int getfrag(void *from, char *to, int offset, int len,
 212                               int odd, struct sk_buff *skb),
 213                   void *from, int len, int protolen,
 214                   struct ipcm_cookie *ipc,
 215                   struct rtable **rt,
 216                   unsigned int flags);
 217int ip_generic_getfrag(void *from, char *to, int offset, int len, int odd,
 218                       struct sk_buff *skb);
 219ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,
 220                       int offset, size_t size, int flags);
 221struct sk_buff *__ip_make_skb(struct sock *sk, struct flowi4 *fl4,
 222                              struct sk_buff_head *queue,
 223                              struct inet_cork *cork);
 224int ip_send_skb(struct net *net, struct sk_buff *skb);
 225int ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4);
 226void ip_flush_pending_frames(struct sock *sk);
 227struct sk_buff *ip_make_skb(struct sock *sk, struct flowi4 *fl4,
 228                            int getfrag(void *from, char *to, int offset,
 229                                        int len, int odd, struct sk_buff *skb),
 230                            void *from, int length, int transhdrlen,
 231                            struct ipcm_cookie *ipc, struct rtable **rtp,
 232                            struct inet_cork *cork, unsigned int flags);
 233
 234static inline int ip_queue_xmit(struct sock *sk, struct sk_buff *skb,
 235                                struct flowi *fl)
 236{
 237        return __ip_queue_xmit(sk, skb, fl, inet_sk(sk)->tos);
 238}
 239
 240static 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
 245static 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
 250static 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 */
 256int __ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
 257int ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
 258
 259void ip4_datagram_release_cb(struct sock *sk);
 260
 261struct 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
 274static 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
 279void 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
 296u64 snmp_get_cpu_field(void __percpu *mib, int cpu, int offct);
 297unsigned long snmp_fold_field(void __percpu *mib, int offt);
 298#if BITS_PER_LONG==32
 299u64 snmp_get_cpu_field64(void __percpu *mib, int cpu, int offct,
 300                         size_t syncp_offset);
 301u64 snmp_fold_field64(void __percpu *mib, int offt, size_t sync_off);
 302#else
 303static inline u64  snmp_get_cpu_field64(void __percpu *mib, int cpu, int offct,
 304                                        size_t syncp_offset)
 305{
 306        return snmp_get_cpu_field(mib, cpu, offct);
 307
 308}
 309
 310static inline u64 snmp_fold_field64(void __percpu *mib, int offt, size_t syncp_off)
 311{
 312        return snmp_fold_field(mib, offt);
 313}
 314#endif
 315
 316#define snmp_get_cpu_field64_batch(buff64, stats_list, mib_statistic, offset) \
 317{ \
 318        int i, c; \
 319        for_each_possible_cpu(c) { \
 320                for (i = 0; stats_list[i].name; i++) \
 321                        buff64[i] += snmp_get_cpu_field64( \
 322                                        mib_statistic, \
 323                                        c, stats_list[i].entry, \
 324                                        offset); \
 325        } \
 326}
 327
 328#define snmp_get_cpu_field_batch(buff, stats_list, mib_statistic) \
 329{ \
 330        int i, c; \
 331        for_each_possible_cpu(c) { \
 332                for (i = 0; stats_list[i].name; i++) \
 333                        buff[i] += snmp_get_cpu_field( \
 334                                                mib_statistic, \
 335                                                c, stats_list[i].entry); \
 336        } \
 337}
 338
 339void inet_get_local_port_range(struct net *net, int *low, int *high);
 340
 341#ifdef CONFIG_SYSCTL
 342static inline int inet_is_local_reserved_port(struct net *net, int port)
 343{
 344        if (!net->ipv4.sysctl_local_reserved_ports)
 345                return 0;
 346        return test_bit(port, net->ipv4.sysctl_local_reserved_ports);
 347}
 348
 349static inline bool sysctl_dev_name_is_allowed(const char *name)
 350{
 351        return strcmp(name, "default") != 0  && strcmp(name, "all") != 0;
 352}
 353
 354static inline int inet_prot_sock(struct net *net)
 355{
 356        return net->ipv4.sysctl_ip_prot_sock;
 357}
 358
 359#else
 360static inline int inet_is_local_reserved_port(struct net *net, int port)
 361{
 362        return 0;
 363}
 364
 365static inline int inet_prot_sock(struct net *net)
 366{
 367        return PROT_SOCK;
 368}
 369#endif
 370
 371__be32 inet_current_timestamp(void);
 372
 373/* From inetpeer.c */
 374extern int inet_peer_threshold;
 375extern int inet_peer_minttl;
 376extern int inet_peer_maxttl;
 377
 378void ipfrag_init(void);
 379
 380void ip_static_sysctl_init(void);
 381
 382#define IP4_REPLY_MARK(net, mark) \
 383        ((net)->ipv4.sysctl_fwmark_reflect ? (mark) : 0)
 384
 385static inline bool ip_is_fragment(const struct iphdr *iph)
 386{
 387        return (iph->frag_off & htons(IP_MF | IP_OFFSET)) != 0;
 388}
 389
 390#ifdef CONFIG_INET
 391#include <net/dst.h>
 392
 393/* The function in 2.2 was invalid, producing wrong result for
 394 * check=0xFEFF. It was noticed by Arthur Skawina _year_ ago. --ANK(000625) */
 395static inline
 396int ip_decrease_ttl(struct iphdr *iph)
 397{
 398        u32 check = (__force u32)iph->check;
 399        check += (__force u32)htons(0x0100);
 400        iph->check = (__force __sum16)(check + (check>=0xFFFF));
 401        return --iph->ttl;
 402}
 403
 404static inline int ip_mtu_locked(const struct dst_entry *dst)
 405{
 406        const struct rtable *rt = (const struct rtable *)dst;
 407
 408        return rt->rt_mtu_locked || dst_metric_locked(dst, RTAX_MTU);
 409}
 410
 411static inline
 412int ip_dont_fragment(const struct sock *sk, const struct dst_entry *dst)
 413{
 414        u8 pmtudisc = READ_ONCE(inet_sk(sk)->pmtudisc);
 415
 416        return  pmtudisc == IP_PMTUDISC_DO ||
 417                (pmtudisc == IP_PMTUDISC_WANT &&
 418                 !ip_mtu_locked(dst));
 419}
 420
 421static inline bool ip_sk_accept_pmtu(const struct sock *sk)
 422{
 423        return inet_sk(sk)->pmtudisc != IP_PMTUDISC_INTERFACE &&
 424               inet_sk(sk)->pmtudisc != IP_PMTUDISC_OMIT;
 425}
 426
 427static inline bool ip_sk_use_pmtu(const struct sock *sk)
 428{
 429        return inet_sk(sk)->pmtudisc < IP_PMTUDISC_PROBE;
 430}
 431
 432static inline bool ip_sk_ignore_df(const struct sock *sk)
 433{
 434        return inet_sk(sk)->pmtudisc < IP_PMTUDISC_DO ||
 435               inet_sk(sk)->pmtudisc == IP_PMTUDISC_OMIT;
 436}
 437
 438static inline unsigned int ip_dst_mtu_maybe_forward(const struct dst_entry *dst,
 439                                                    bool forwarding)
 440{
 441        struct net *net = dev_net(dst->dev);
 442
 443        if (net->ipv4.sysctl_ip_fwd_use_pmtu ||
 444            ip_mtu_locked(dst) ||
 445            !forwarding)
 446                return dst_mtu(dst);
 447
 448        return min(READ_ONCE(dst->dev->mtu), IP_MAX_MTU);
 449}
 450
 451static inline unsigned int ip_skb_dst_mtu(struct sock *sk,
 452                                          const struct sk_buff *skb)
 453{
 454        if (!sk || !sk_fullsock(sk) || ip_sk_use_pmtu(sk)) {
 455                bool forwarding = IPCB(skb)->flags & IPSKB_FORWARDED;
 456
 457                return ip_dst_mtu_maybe_forward(skb_dst(skb), forwarding);
 458        }
 459
 460        return min(READ_ONCE(skb_dst(skb)->dev->mtu), IP_MAX_MTU);
 461}
 462
 463struct dst_metrics *ip_fib_metrics_init(struct net *net, struct nlattr *fc_mx,
 464                                        int fc_mx_len,
 465                                        struct netlink_ext_ack *extack);
 466static inline void ip_fib_metrics_put(struct dst_metrics *fib_metrics)
 467{
 468        if (fib_metrics != &dst_default_metrics &&
 469            refcount_dec_and_test(&fib_metrics->refcnt))
 470                kfree(fib_metrics);
 471}
 472
 473/* ipv4 and ipv6 both use refcounted metrics if it is not the default */
 474static inline
 475void ip_dst_init_metrics(struct dst_entry *dst, struct dst_metrics *fib_metrics)
 476{
 477        dst_init_metrics(dst, fib_metrics->metrics, true);
 478
 479        if (fib_metrics != &dst_default_metrics) {
 480                dst->_metrics |= DST_METRICS_REFCOUNTED;
 481                refcount_inc(&fib_metrics->refcnt);
 482        }
 483}
 484
 485static inline
 486void ip_dst_metrics_put(struct dst_entry *dst)
 487{
 488        struct dst_metrics *p = (struct dst_metrics *)DST_METRICS_PTR(dst);
 489
 490        if (p != &dst_default_metrics && refcount_dec_and_test(&p->refcnt))
 491                kfree(p);
 492}
 493
 494u32 ip_idents_reserve(u32 hash, int segs);
 495void __ip_select_ident(struct net *net, struct iphdr *iph, int segs);
 496
 497static inline void ip_select_ident_segs(struct net *net, struct sk_buff *skb,
 498                                        struct sock *sk, int segs)
 499{
 500        struct iphdr *iph = ip_hdr(skb);
 501
 502        if ((iph->frag_off & htons(IP_DF)) && !skb->ignore_df) {
 503                /* This is only to work around buggy Windows95/2000
 504                 * VJ compression implementations.  If the ID field
 505                 * does not change, they drop every other packet in
 506                 * a TCP stream using header compression.
 507                 */
 508                if (sk && inet_sk(sk)->inet_daddr) {
 509                        iph->id = htons(inet_sk(sk)->inet_id);
 510                        inet_sk(sk)->inet_id += segs;
 511                } else {
 512                        iph->id = 0;
 513                }
 514        } else {
 515                __ip_select_ident(net, iph, segs);
 516        }
 517}
 518
 519static inline void ip_select_ident(struct net *net, struct sk_buff *skb,
 520                                   struct sock *sk)
 521{
 522        ip_select_ident_segs(net, skb, sk, 1);
 523}
 524
 525static inline __wsum inet_compute_pseudo(struct sk_buff *skb, int proto)
 526{
 527        return csum_tcpudp_nofold(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
 528                                  skb->len, proto, 0);
 529}
 530
 531/* copy IPv4 saddr & daddr to flow_keys, possibly using 64bit load/store
 532 * Equivalent to :      flow->v4addrs.src = iph->saddr;
 533 *                      flow->v4addrs.dst = iph->daddr;
 534 */
 535static inline void iph_to_flow_copy_v4addrs(struct flow_keys *flow,
 536                                            const struct iphdr *iph)
 537{
 538        BUILD_BUG_ON(offsetof(typeof(flow->addrs), v4addrs.dst) !=
 539                     offsetof(typeof(flow->addrs), v4addrs.src) +
 540                              sizeof(flow->addrs.v4addrs.src));
 541        memcpy(&flow->addrs.v4addrs, &iph->saddr, sizeof(flow->addrs.v4addrs));
 542        flow->control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
 543}
 544
 545static inline __wsum inet_gro_compute_pseudo(struct sk_buff *skb, int proto)
 546{
 547        const struct iphdr *iph = skb_gro_network_header(skb);
 548
 549        return csum_tcpudp_nofold(iph->saddr, iph->daddr,
 550                                  skb_gro_len(skb), proto, 0);
 551}
 552
 553/*
 554 *      Map a multicast IP onto multicast MAC for type ethernet.
 555 */
 556
 557static inline void ip_eth_mc_map(__be32 naddr, char *buf)
 558{
 559        __u32 addr=ntohl(naddr);
 560        buf[0]=0x01;
 561        buf[1]=0x00;
 562        buf[2]=0x5e;
 563        buf[5]=addr&0xFF;
 564        addr>>=8;
 565        buf[4]=addr&0xFF;
 566        addr>>=8;
 567        buf[3]=addr&0x7F;
 568}
 569
 570/*
 571 *      Map a multicast IP onto multicast MAC for type IP-over-InfiniBand.
 572 *      Leave P_Key as 0 to be filled in by driver.
 573 */
 574
 575static inline void ip_ib_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
 576{
 577        __u32 addr;
 578        unsigned char scope = broadcast[5] & 0xF;
 579
 580        buf[0]  = 0;            /* Reserved */
 581        buf[1]  = 0xff;         /* Multicast QPN */
 582        buf[2]  = 0xff;
 583        buf[3]  = 0xff;
 584        addr    = ntohl(naddr);
 585        buf[4]  = 0xff;
 586        buf[5]  = 0x10 | scope; /* scope from broadcast address */
 587        buf[6]  = 0x40;         /* IPv4 signature */
 588        buf[7]  = 0x1b;
 589        buf[8]  = broadcast[8];         /* P_Key */
 590        buf[9]  = broadcast[9];
 591        buf[10] = 0;
 592        buf[11] = 0;
 593        buf[12] = 0;
 594        buf[13] = 0;
 595        buf[14] = 0;
 596        buf[15] = 0;
 597        buf[19] = addr & 0xff;
 598        addr  >>= 8;
 599        buf[18] = addr & 0xff;
 600        addr  >>= 8;
 601        buf[17] = addr & 0xff;
 602        addr  >>= 8;
 603        buf[16] = addr & 0x0f;
 604}
 605
 606static inline void ip_ipgre_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
 607{
 608        if ((broadcast[0] | broadcast[1] | broadcast[2] | broadcast[3]) != 0)
 609                memcpy(buf, broadcast, 4);
 610        else
 611                memcpy(buf, &naddr, sizeof(naddr));
 612}
 613
 614#if IS_ENABLED(CONFIG_IPV6)
 615#include <linux/ipv6.h>
 616#endif
 617
 618static __inline__ void inet_reset_saddr(struct sock *sk)
 619{
 620        inet_sk(sk)->inet_rcv_saddr = inet_sk(sk)->inet_saddr = 0;
 621#if IS_ENABLED(CONFIG_IPV6)
 622        if (sk->sk_family == PF_INET6) {
 623                struct ipv6_pinfo *np = inet6_sk(sk);
 624
 625                memset(&np->saddr, 0, sizeof(np->saddr));
 626                memset(&sk->sk_v6_rcv_saddr, 0, sizeof(sk->sk_v6_rcv_saddr));
 627        }
 628#endif
 629}
 630
 631#endif
 632
 633static inline unsigned int ipv4_addr_hash(__be32 ip)
 634{
 635        return (__force unsigned int) ip;
 636}
 637
 638static inline u32 ipv4_portaddr_hash(const struct net *net,
 639                                     __be32 saddr,
 640                                     unsigned int port)
 641{
 642        return jhash_1word((__force u32)saddr, net_hash_mix(net)) ^ port;
 643}
 644
 645bool ip_call_ra_chain(struct sk_buff *skb);
 646
 647/*
 648 *      Functions provided by ip_fragment.c
 649 */
 650
 651enum ip_defrag_users {
 652        IP_DEFRAG_LOCAL_DELIVER,
 653        IP_DEFRAG_CALL_RA_CHAIN,
 654        IP_DEFRAG_CONNTRACK_IN,
 655        __IP_DEFRAG_CONNTRACK_IN_END    = IP_DEFRAG_CONNTRACK_IN + USHRT_MAX,
 656        IP_DEFRAG_CONNTRACK_OUT,
 657        __IP_DEFRAG_CONNTRACK_OUT_END   = IP_DEFRAG_CONNTRACK_OUT + USHRT_MAX,
 658        IP_DEFRAG_CONNTRACK_BRIDGE_IN,
 659        __IP_DEFRAG_CONNTRACK_BRIDGE_IN = IP_DEFRAG_CONNTRACK_BRIDGE_IN + USHRT_MAX,
 660        IP_DEFRAG_VS_IN,
 661        IP_DEFRAG_VS_OUT,
 662        IP_DEFRAG_VS_FWD,
 663        IP_DEFRAG_AF_PACKET,
 664        IP_DEFRAG_MACVLAN,
 665};
 666
 667/* Return true if the value of 'user' is between 'lower_bond'
 668 * and 'upper_bond' inclusively.
 669 */
 670static inline bool ip_defrag_user_in_between(u32 user,
 671                                             enum ip_defrag_users lower_bond,
 672                                             enum ip_defrag_users upper_bond)
 673{
 674        return user >= lower_bond && user <= upper_bond;
 675}
 676
 677int ip_defrag(struct net *net, struct sk_buff *skb, u32 user);
 678#ifdef CONFIG_INET
 679struct sk_buff *ip_check_defrag(struct net *net, struct sk_buff *skb, u32 user);
 680#else
 681static inline struct sk_buff *ip_check_defrag(struct net *net, struct sk_buff *skb, u32 user)
 682{
 683        return skb;
 684}
 685#endif
 686
 687/*
 688 *      Functions provided by ip_forward.c
 689 */
 690
 691int ip_forward(struct sk_buff *skb);
 692
 693/*
 694 *      Functions provided by ip_options.c
 695 */
 696
 697void ip_options_build(struct sk_buff *skb, struct ip_options *opt,
 698                      __be32 daddr, struct rtable *rt, int is_frag);
 699
 700int __ip_options_echo(struct net *net, struct ip_options *dopt,
 701                      struct sk_buff *skb, const struct ip_options *sopt);
 702static inline int ip_options_echo(struct net *net, struct ip_options *dopt,
 703                                  struct sk_buff *skb)
 704{
 705        return __ip_options_echo(net, dopt, skb, &IPCB(skb)->opt);
 706}
 707
 708void ip_options_fragment(struct sk_buff *skb);
 709int __ip_options_compile(struct net *net, struct ip_options *opt,
 710                         struct sk_buff *skb, __be32 *info);
 711int ip_options_compile(struct net *net, struct ip_options *opt,
 712                       struct sk_buff *skb);
 713int ip_options_get(struct net *net, struct ip_options_rcu **optp,
 714                   unsigned char *data, int optlen);
 715int ip_options_get_from_user(struct net *net, struct ip_options_rcu **optp,
 716                             unsigned char __user *data, int optlen);
 717void ip_options_undo(struct ip_options *opt);
 718void ip_forward_options(struct sk_buff *skb);
 719int ip_options_rcv_srr(struct sk_buff *skb, struct net_device *dev);
 720
 721/*
 722 *      Functions provided by ip_sockglue.c
 723 */
 724
 725void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb);
 726void ip_cmsg_recv_offset(struct msghdr *msg, struct sock *sk,
 727                         struct sk_buff *skb, int tlen, int offset);
 728int ip_cmsg_send(struct sock *sk, struct msghdr *msg,
 729                 struct ipcm_cookie *ipc, bool allow_ipv6);
 730int ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
 731                  unsigned int optlen);
 732int ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
 733                  int __user *optlen);
 734int compat_ip_setsockopt(struct sock *sk, int level, int optname,
 735                         char __user *optval, unsigned int optlen);
 736int compat_ip_getsockopt(struct sock *sk, int level, int optname,
 737                         char __user *optval, int __user *optlen);
 738int ip_ra_control(struct sock *sk, unsigned char on,
 739                  void (*destructor)(struct sock *));
 740
 741int ip_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len);
 742void ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err, __be16 port,
 743                   u32 info, u8 *payload);
 744void ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 dport,
 745                    u32 info);
 746
 747static inline void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb)
 748{
 749        ip_cmsg_recv_offset(msg, skb->sk, skb, 0, 0);
 750}
 751
 752bool icmp_global_allow(void);
 753extern int sysctl_icmp_msgs_per_sec;
 754extern int sysctl_icmp_msgs_burst;
 755
 756#ifdef CONFIG_PROC_FS
 757int ip_misc_proc_init(void);
 758#endif
 759
 760int rtm_getroute_parse_ip_proto(struct nlattr *attr, u8 *ip_proto, u8 family,
 761                                struct netlink_ext_ack *extack);
 762
 763#endif  /* _IP_H */
 764