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.tsflags = inet->sk.sk_tsflags;
  92        ipcm->oif = inet->sk.sk_bound_dev_if;
  93        ipcm->addr = inet->inet_saddr;
  94}
  95
  96#define IPCB(skb) ((struct inet_skb_parm*)((skb)->cb))
  97#define PKTINFO_SKB_CB(skb) ((struct in_pktinfo *)((skb)->cb))
  98
  99/* return enslaved device index if relevant */
 100static inline int inet_sdif(struct sk_buff *skb)
 101{
 102#if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
 103        if (skb && ipv4_l3mdev_skb(IPCB(skb)->flags))
 104                return IPCB(skb)->iif;
 105#endif
 106        return 0;
 107}
 108
 109/* Special input handler for packets caught by router alert option.
 110   They are selected only by protocol field, and then processed likely
 111   local ones; but only if someone wants them! Otherwise, router
 112   not running rsvpd will kill RSVP.
 113
 114   It is user level problem, what it will make with them.
 115   I have no idea, how it will masquearde or NAT them (it is joke, joke :-)),
 116   but receiver should be enough clever f.e. to forward mtrace requests,
 117   sent to multicast group to reach destination designated router.
 118 */
 119
 120struct ip_ra_chain {
 121        struct ip_ra_chain __rcu *next;
 122        struct sock             *sk;
 123        union {
 124                void                    (*destructor)(struct sock *);
 125                struct sock             *saved_sk;
 126        };
 127        struct rcu_head         rcu;
 128};
 129
 130/* IP flags. */
 131#define IP_CE           0x8000          /* Flag: "Congestion"           */
 132#define IP_DF           0x4000          /* Flag: "Don't Fragment"       */
 133#define IP_MF           0x2000          /* Flag: "More Fragments"       */
 134#define IP_OFFSET       0x1FFF          /* "Fragment Offset" part       */
 135
 136#define IP_FRAG_TIME    (30 * HZ)               /* fragment lifetime    */
 137
 138struct msghdr;
 139struct net_device;
 140struct packet_type;
 141struct rtable;
 142struct sockaddr;
 143
 144int igmp_mc_init(void);
 145
 146/*
 147 *      Functions provided by ip.c
 148 */
 149
 150int ip_build_and_send_pkt(struct sk_buff *skb, const struct sock *sk,
 151                          __be32 saddr, __be32 daddr,
 152                          struct ip_options_rcu *opt);
 153int ip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt,
 154           struct net_device *orig_dev);
 155void ip_list_rcv(struct list_head *head, struct packet_type *pt,
 156                 struct net_device *orig_dev);
 157int ip_local_deliver(struct sk_buff *skb);
 158void ip_protocol_deliver_rcu(struct net *net, struct sk_buff *skb, int proto);
 159int ip_mr_input(struct sk_buff *skb);
 160int ip_output(struct net *net, struct sock *sk, struct sk_buff *skb);
 161int ip_mc_output(struct net *net, struct sock *sk, struct sk_buff *skb);
 162int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
 163                   int (*output)(struct net *, struct sock *, struct sk_buff *));
 164void ip_send_check(struct iphdr *ip);
 165int __ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb);
 166int ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb);
 167
 168int __ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl,
 169                    __u8 tos);
 170void ip_init(void);
 171int ip_append_data(struct sock *sk, struct flowi4 *fl4,
 172                   int getfrag(void *from, char *to, int offset, int len,
 173                               int odd, struct sk_buff *skb),
 174                   void *from, int len, int protolen,
 175                   struct ipcm_cookie *ipc,
 176                   struct rtable **rt,
 177                   unsigned int flags);
 178int ip_generic_getfrag(void *from, char *to, int offset, int len, int odd,
 179                       struct sk_buff *skb);
 180ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,
 181                       int offset, size_t size, int flags);
 182struct sk_buff *__ip_make_skb(struct sock *sk, struct flowi4 *fl4,
 183                              struct sk_buff_head *queue,
 184                              struct inet_cork *cork);
 185int ip_send_skb(struct net *net, struct sk_buff *skb);
 186int ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4);
 187void ip_flush_pending_frames(struct sock *sk);
 188struct sk_buff *ip_make_skb(struct sock *sk, struct flowi4 *fl4,
 189                            int getfrag(void *from, char *to, int offset,
 190                                        int len, int odd, struct sk_buff *skb),
 191                            void *from, int length, int transhdrlen,
 192                            struct ipcm_cookie *ipc, struct rtable **rtp,
 193                            struct inet_cork *cork, unsigned int flags);
 194
 195static inline int ip_queue_xmit(struct sock *sk, struct sk_buff *skb,
 196                                struct flowi *fl)
 197{
 198        return __ip_queue_xmit(sk, skb, fl, inet_sk(sk)->tos);
 199}
 200
 201static inline struct sk_buff *ip_finish_skb(struct sock *sk, struct flowi4 *fl4)
 202{
 203        return __ip_make_skb(sk, fl4, &sk->sk_write_queue, &inet_sk(sk)->cork.base);
 204}
 205
 206static inline __u8 get_rttos(struct ipcm_cookie* ipc, struct inet_sock *inet)
 207{
 208        return (ipc->tos != -1) ? RT_TOS(ipc->tos) : RT_TOS(inet->tos);
 209}
 210
 211static inline __u8 get_rtconn_flags(struct ipcm_cookie* ipc, struct sock* sk)
 212{
 213        return (ipc->tos != -1) ? RT_CONN_FLAGS_TOS(sk, ipc->tos) : RT_CONN_FLAGS(sk);
 214}
 215
 216/* datagram.c */
 217int __ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
 218int ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
 219
 220void ip4_datagram_release_cb(struct sock *sk);
 221
 222struct ip_reply_arg {
 223        struct kvec iov[1];
 224        int         flags;
 225        __wsum      csum;
 226        int         csumoffset; /* u16 offset of csum in iov[0].iov_base */
 227                                /* -1 if not needed */
 228        int         bound_dev_if;
 229        u8          tos;
 230        kuid_t      uid;
 231};
 232
 233#define IP_REPLY_ARG_NOSRCCHECK 1
 234
 235static inline __u8 ip_reply_arg_flowi_flags(const struct ip_reply_arg *arg)
 236{
 237        return (arg->flags & IP_REPLY_ARG_NOSRCCHECK) ? FLOWI_FLAG_ANYSRC : 0;
 238}
 239
 240void ip_send_unicast_reply(struct sock *sk, struct sk_buff *skb,
 241                           const struct ip_options *sopt,
 242                           __be32 daddr, __be32 saddr,
 243                           const struct ip_reply_arg *arg,
 244                           unsigned int len);
 245
 246#define IP_INC_STATS(net, field)        SNMP_INC_STATS64((net)->mib.ip_statistics, field)
 247#define __IP_INC_STATS(net, field)      __SNMP_INC_STATS64((net)->mib.ip_statistics, field)
 248#define IP_ADD_STATS(net, field, val)   SNMP_ADD_STATS64((net)->mib.ip_statistics, field, val)
 249#define __IP_ADD_STATS(net, field, val) __SNMP_ADD_STATS64((net)->mib.ip_statistics, field, val)
 250#define IP_UPD_PO_STATS(net, field, val) SNMP_UPD_PO_STATS64((net)->mib.ip_statistics, field, val)
 251#define __IP_UPD_PO_STATS(net, field, val) __SNMP_UPD_PO_STATS64((net)->mib.ip_statistics, field, val)
 252#define NET_INC_STATS(net, field)       SNMP_INC_STATS((net)->mib.net_statistics, field)
 253#define __NET_INC_STATS(net, field)     __SNMP_INC_STATS((net)->mib.net_statistics, field)
 254#define NET_ADD_STATS(net, field, adnd) SNMP_ADD_STATS((net)->mib.net_statistics, field, adnd)
 255#define __NET_ADD_STATS(net, field, adnd) __SNMP_ADD_STATS((net)->mib.net_statistics, field, adnd)
 256
 257u64 snmp_get_cpu_field(void __percpu *mib, int cpu, int offct);
 258unsigned long snmp_fold_field(void __percpu *mib, int offt);
 259#if BITS_PER_LONG==32
 260u64 snmp_get_cpu_field64(void __percpu *mib, int cpu, int offct,
 261                         size_t syncp_offset);
 262u64 snmp_fold_field64(void __percpu *mib, int offt, size_t sync_off);
 263#else
 264static inline u64  snmp_get_cpu_field64(void __percpu *mib, int cpu, int offct,
 265                                        size_t syncp_offset)
 266{
 267        return snmp_get_cpu_field(mib, cpu, offct);
 268
 269}
 270
 271static inline u64 snmp_fold_field64(void __percpu *mib, int offt, size_t syncp_off)
 272{
 273        return snmp_fold_field(mib, offt);
 274}
 275#endif
 276
 277#define snmp_get_cpu_field64_batch(buff64, stats_list, mib_statistic, offset) \
 278{ \
 279        int i, c; \
 280        for_each_possible_cpu(c) { \
 281                for (i = 0; stats_list[i].name; i++) \
 282                        buff64[i] += snmp_get_cpu_field64( \
 283                                        mib_statistic, \
 284                                        c, stats_list[i].entry, \
 285                                        offset); \
 286        } \
 287}
 288
 289#define snmp_get_cpu_field_batch(buff, stats_list, mib_statistic) \
 290{ \
 291        int i, c; \
 292        for_each_possible_cpu(c) { \
 293                for (i = 0; stats_list[i].name; i++) \
 294                        buff[i] += snmp_get_cpu_field( \
 295                                                mib_statistic, \
 296                                                c, stats_list[i].entry); \
 297        } \
 298}
 299
 300void inet_get_local_port_range(struct net *net, int *low, int *high);
 301
 302#ifdef CONFIG_SYSCTL
 303static inline int inet_is_local_reserved_port(struct net *net, int port)
 304{
 305        if (!net->ipv4.sysctl_local_reserved_ports)
 306                return 0;
 307        return test_bit(port, net->ipv4.sysctl_local_reserved_ports);
 308}
 309
 310static inline bool sysctl_dev_name_is_allowed(const char *name)
 311{
 312        return strcmp(name, "default") != 0  && strcmp(name, "all") != 0;
 313}
 314
 315static inline int inet_prot_sock(struct net *net)
 316{
 317        return net->ipv4.sysctl_ip_prot_sock;
 318}
 319
 320#else
 321static inline int inet_is_local_reserved_port(struct net *net, int port)
 322{
 323        return 0;
 324}
 325
 326static inline int inet_prot_sock(struct net *net)
 327{
 328        return PROT_SOCK;
 329}
 330#endif
 331
 332__be32 inet_current_timestamp(void);
 333
 334/* From inetpeer.c */
 335extern int inet_peer_threshold;
 336extern int inet_peer_minttl;
 337extern int inet_peer_maxttl;
 338
 339void ipfrag_init(void);
 340
 341void ip_static_sysctl_init(void);
 342
 343#define IP4_REPLY_MARK(net, mark) \
 344        ((net)->ipv4.sysctl_fwmark_reflect ? (mark) : 0)
 345
 346static inline bool ip_is_fragment(const struct iphdr *iph)
 347{
 348        return (iph->frag_off & htons(IP_MF | IP_OFFSET)) != 0;
 349}
 350
 351#ifdef CONFIG_INET
 352#include <net/dst.h>
 353
 354/* The function in 2.2 was invalid, producing wrong result for
 355 * check=0xFEFF. It was noticed by Arthur Skawina _year_ ago. --ANK(000625) */
 356static inline
 357int ip_decrease_ttl(struct iphdr *iph)
 358{
 359        u32 check = (__force u32)iph->check;
 360        check += (__force u32)htons(0x0100);
 361        iph->check = (__force __sum16)(check + (check>=0xFFFF));
 362        return --iph->ttl;
 363}
 364
 365static inline int ip_mtu_locked(const struct dst_entry *dst)
 366{
 367        const struct rtable *rt = (const struct rtable *)dst;
 368
 369        return rt->rt_mtu_locked || dst_metric_locked(dst, RTAX_MTU);
 370}
 371
 372static inline
 373int ip_dont_fragment(const struct sock *sk, const struct dst_entry *dst)
 374{
 375        u8 pmtudisc = READ_ONCE(inet_sk(sk)->pmtudisc);
 376
 377        return  pmtudisc == IP_PMTUDISC_DO ||
 378                (pmtudisc == IP_PMTUDISC_WANT &&
 379                 !ip_mtu_locked(dst));
 380}
 381
 382static inline bool ip_sk_accept_pmtu(const struct sock *sk)
 383{
 384        return inet_sk(sk)->pmtudisc != IP_PMTUDISC_INTERFACE &&
 385               inet_sk(sk)->pmtudisc != IP_PMTUDISC_OMIT;
 386}
 387
 388static inline bool ip_sk_use_pmtu(const struct sock *sk)
 389{
 390        return inet_sk(sk)->pmtudisc < IP_PMTUDISC_PROBE;
 391}
 392
 393static inline bool ip_sk_ignore_df(const struct sock *sk)
 394{
 395        return inet_sk(sk)->pmtudisc < IP_PMTUDISC_DO ||
 396               inet_sk(sk)->pmtudisc == IP_PMTUDISC_OMIT;
 397}
 398
 399static inline unsigned int ip_dst_mtu_maybe_forward(const struct dst_entry *dst,
 400                                                    bool forwarding)
 401{
 402        struct net *net = dev_net(dst->dev);
 403
 404        if (net->ipv4.sysctl_ip_fwd_use_pmtu ||
 405            ip_mtu_locked(dst) ||
 406            !forwarding)
 407                return dst_mtu(dst);
 408
 409        return min(READ_ONCE(dst->dev->mtu), IP_MAX_MTU);
 410}
 411
 412static inline unsigned int ip_skb_dst_mtu(struct sock *sk,
 413                                          const struct sk_buff *skb)
 414{
 415        if (!sk || !sk_fullsock(sk) || ip_sk_use_pmtu(sk)) {
 416                bool forwarding = IPCB(skb)->flags & IPSKB_FORWARDED;
 417
 418                return ip_dst_mtu_maybe_forward(skb_dst(skb), forwarding);
 419        }
 420
 421        return min(READ_ONCE(skb_dst(skb)->dev->mtu), IP_MAX_MTU);
 422}
 423
 424struct dst_metrics *ip_fib_metrics_init(struct net *net, struct nlattr *fc_mx,
 425                                        int fc_mx_len,
 426                                        struct netlink_ext_ack *extack);
 427static inline void ip_fib_metrics_put(struct dst_metrics *fib_metrics)
 428{
 429        if (fib_metrics != &dst_default_metrics &&
 430            refcount_dec_and_test(&fib_metrics->refcnt))
 431                kfree(fib_metrics);
 432}
 433
 434/* ipv4 and ipv6 both use refcounted metrics if it is not the default */
 435static inline
 436void ip_dst_init_metrics(struct dst_entry *dst, struct dst_metrics *fib_metrics)
 437{
 438        dst_init_metrics(dst, fib_metrics->metrics, true);
 439
 440        if (fib_metrics != &dst_default_metrics) {
 441                dst->_metrics |= DST_METRICS_REFCOUNTED;
 442                refcount_inc(&fib_metrics->refcnt);
 443        }
 444}
 445
 446static inline
 447void ip_dst_metrics_put(struct dst_entry *dst)
 448{
 449        struct dst_metrics *p = (struct dst_metrics *)DST_METRICS_PTR(dst);
 450
 451        if (p != &dst_default_metrics && refcount_dec_and_test(&p->refcnt))
 452                kfree(p);
 453}
 454
 455u32 ip_idents_reserve(u32 hash, int segs);
 456void __ip_select_ident(struct net *net, struct iphdr *iph, int segs);
 457
 458static inline void ip_select_ident_segs(struct net *net, struct sk_buff *skb,
 459                                        struct sock *sk, int segs)
 460{
 461        struct iphdr *iph = ip_hdr(skb);
 462
 463        if ((iph->frag_off & htons(IP_DF)) && !skb->ignore_df) {
 464                /* This is only to work around buggy Windows95/2000
 465                 * VJ compression implementations.  If the ID field
 466                 * does not change, they drop every other packet in
 467                 * a TCP stream using header compression.
 468                 */
 469                if (sk && inet_sk(sk)->inet_daddr) {
 470                        iph->id = htons(inet_sk(sk)->inet_id);
 471                        inet_sk(sk)->inet_id += segs;
 472                } else {
 473                        iph->id = 0;
 474                }
 475        } else {
 476                __ip_select_ident(net, iph, segs);
 477        }
 478}
 479
 480static inline void ip_select_ident(struct net *net, struct sk_buff *skb,
 481                                   struct sock *sk)
 482{
 483        ip_select_ident_segs(net, skb, sk, 1);
 484}
 485
 486static inline __wsum inet_compute_pseudo(struct sk_buff *skb, int proto)
 487{
 488        return csum_tcpudp_nofold(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
 489                                  skb->len, proto, 0);
 490}
 491
 492/* copy IPv4 saddr & daddr to flow_keys, possibly using 64bit load/store
 493 * Equivalent to :      flow->v4addrs.src = iph->saddr;
 494 *                      flow->v4addrs.dst = iph->daddr;
 495 */
 496static inline void iph_to_flow_copy_v4addrs(struct flow_keys *flow,
 497                                            const struct iphdr *iph)
 498{
 499        BUILD_BUG_ON(offsetof(typeof(flow->addrs), v4addrs.dst) !=
 500                     offsetof(typeof(flow->addrs), v4addrs.src) +
 501                              sizeof(flow->addrs.v4addrs.src));
 502        memcpy(&flow->addrs.v4addrs, &iph->saddr, sizeof(flow->addrs.v4addrs));
 503        flow->control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
 504}
 505
 506static inline __wsum inet_gro_compute_pseudo(struct sk_buff *skb, int proto)
 507{
 508        const struct iphdr *iph = skb_gro_network_header(skb);
 509
 510        return csum_tcpudp_nofold(iph->saddr, iph->daddr,
 511                                  skb_gro_len(skb), proto, 0);
 512}
 513
 514/*
 515 *      Map a multicast IP onto multicast MAC for type ethernet.
 516 */
 517
 518static inline void ip_eth_mc_map(__be32 naddr, char *buf)
 519{
 520        __u32 addr=ntohl(naddr);
 521        buf[0]=0x01;
 522        buf[1]=0x00;
 523        buf[2]=0x5e;
 524        buf[5]=addr&0xFF;
 525        addr>>=8;
 526        buf[4]=addr&0xFF;
 527        addr>>=8;
 528        buf[3]=addr&0x7F;
 529}
 530
 531/*
 532 *      Map a multicast IP onto multicast MAC for type IP-over-InfiniBand.
 533 *      Leave P_Key as 0 to be filled in by driver.
 534 */
 535
 536static inline void ip_ib_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
 537{
 538        __u32 addr;
 539        unsigned char scope = broadcast[5] & 0xF;
 540
 541        buf[0]  = 0;            /* Reserved */
 542        buf[1]  = 0xff;         /* Multicast QPN */
 543        buf[2]  = 0xff;
 544        buf[3]  = 0xff;
 545        addr    = ntohl(naddr);
 546        buf[4]  = 0xff;
 547        buf[5]  = 0x10 | scope; /* scope from broadcast address */
 548        buf[6]  = 0x40;         /* IPv4 signature */
 549        buf[7]  = 0x1b;
 550        buf[8]  = broadcast[8];         /* P_Key */
 551        buf[9]  = broadcast[9];
 552        buf[10] = 0;
 553        buf[11] = 0;
 554        buf[12] = 0;
 555        buf[13] = 0;
 556        buf[14] = 0;
 557        buf[15] = 0;
 558        buf[19] = addr & 0xff;
 559        addr  >>= 8;
 560        buf[18] = addr & 0xff;
 561        addr  >>= 8;
 562        buf[17] = addr & 0xff;
 563        addr  >>= 8;
 564        buf[16] = addr & 0x0f;
 565}
 566
 567static inline void ip_ipgre_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
 568{
 569        if ((broadcast[0] | broadcast[1] | broadcast[2] | broadcast[3]) != 0)
 570                memcpy(buf, broadcast, 4);
 571        else
 572                memcpy(buf, &naddr, sizeof(naddr));
 573}
 574
 575#if IS_ENABLED(CONFIG_IPV6)
 576#include <linux/ipv6.h>
 577#endif
 578
 579static __inline__ void inet_reset_saddr(struct sock *sk)
 580{
 581        inet_sk(sk)->inet_rcv_saddr = inet_sk(sk)->inet_saddr = 0;
 582#if IS_ENABLED(CONFIG_IPV6)
 583        if (sk->sk_family == PF_INET6) {
 584                struct ipv6_pinfo *np = inet6_sk(sk);
 585
 586                memset(&np->saddr, 0, sizeof(np->saddr));
 587                memset(&sk->sk_v6_rcv_saddr, 0, sizeof(sk->sk_v6_rcv_saddr));
 588        }
 589#endif
 590}
 591
 592#endif
 593
 594static inline unsigned int ipv4_addr_hash(__be32 ip)
 595{
 596        return (__force unsigned int) ip;
 597}
 598
 599static inline u32 ipv4_portaddr_hash(const struct net *net,
 600                                     __be32 saddr,
 601                                     unsigned int port)
 602{
 603        return jhash_1word((__force u32)saddr, net_hash_mix(net)) ^ port;
 604}
 605
 606bool ip_call_ra_chain(struct sk_buff *skb);
 607
 608/*
 609 *      Functions provided by ip_fragment.c
 610 */
 611
 612enum ip_defrag_users {
 613        IP_DEFRAG_LOCAL_DELIVER,
 614        IP_DEFRAG_CALL_RA_CHAIN,
 615        IP_DEFRAG_CONNTRACK_IN,
 616        __IP_DEFRAG_CONNTRACK_IN_END    = IP_DEFRAG_CONNTRACK_IN + USHRT_MAX,
 617        IP_DEFRAG_CONNTRACK_OUT,
 618        __IP_DEFRAG_CONNTRACK_OUT_END   = IP_DEFRAG_CONNTRACK_OUT + USHRT_MAX,
 619        IP_DEFRAG_CONNTRACK_BRIDGE_IN,
 620        __IP_DEFRAG_CONNTRACK_BRIDGE_IN = IP_DEFRAG_CONNTRACK_BRIDGE_IN + USHRT_MAX,
 621        IP_DEFRAG_VS_IN,
 622        IP_DEFRAG_VS_OUT,
 623        IP_DEFRAG_VS_FWD,
 624        IP_DEFRAG_AF_PACKET,
 625        IP_DEFRAG_MACVLAN,
 626};
 627
 628/* Return true if the value of 'user' is between 'lower_bond'
 629 * and 'upper_bond' inclusively.
 630 */
 631static inline bool ip_defrag_user_in_between(u32 user,
 632                                             enum ip_defrag_users lower_bond,
 633                                             enum ip_defrag_users upper_bond)
 634{
 635        return user >= lower_bond && user <= upper_bond;
 636}
 637
 638int ip_defrag(struct net *net, struct sk_buff *skb, u32 user);
 639#ifdef CONFIG_INET
 640struct sk_buff *ip_check_defrag(struct net *net, struct sk_buff *skb, u32 user);
 641#else
 642static inline struct sk_buff *ip_check_defrag(struct net *net, struct sk_buff *skb, u32 user)
 643{
 644        return skb;
 645}
 646#endif
 647
 648/*
 649 *      Functions provided by ip_forward.c
 650 */
 651
 652int ip_forward(struct sk_buff *skb);
 653
 654/*
 655 *      Functions provided by ip_options.c
 656 */
 657
 658void ip_options_build(struct sk_buff *skb, struct ip_options *opt,
 659                      __be32 daddr, struct rtable *rt, int is_frag);
 660
 661int __ip_options_echo(struct net *net, struct ip_options *dopt,
 662                      struct sk_buff *skb, const struct ip_options *sopt);
 663static inline int ip_options_echo(struct net *net, struct ip_options *dopt,
 664                                  struct sk_buff *skb)
 665{
 666        return __ip_options_echo(net, dopt, skb, &IPCB(skb)->opt);
 667}
 668
 669void ip_options_fragment(struct sk_buff *skb);
 670int __ip_options_compile(struct net *net, struct ip_options *opt,
 671                         struct sk_buff *skb, __be32 *info);
 672int ip_options_compile(struct net *net, struct ip_options *opt,
 673                       struct sk_buff *skb);
 674int ip_options_get(struct net *net, struct ip_options_rcu **optp,
 675                   unsigned char *data, int optlen);
 676int ip_options_get_from_user(struct net *net, struct ip_options_rcu **optp,
 677                             unsigned char __user *data, int optlen);
 678void ip_options_undo(struct ip_options *opt);
 679void ip_forward_options(struct sk_buff *skb);
 680int ip_options_rcv_srr(struct sk_buff *skb, struct net_device *dev);
 681
 682/*
 683 *      Functions provided by ip_sockglue.c
 684 */
 685
 686void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb);
 687void ip_cmsg_recv_offset(struct msghdr *msg, struct sock *sk,
 688                         struct sk_buff *skb, int tlen, int offset);
 689int ip_cmsg_send(struct sock *sk, struct msghdr *msg,
 690                 struct ipcm_cookie *ipc, bool allow_ipv6);
 691int ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
 692                  unsigned int optlen);
 693int ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
 694                  int __user *optlen);
 695int compat_ip_setsockopt(struct sock *sk, int level, int optname,
 696                         char __user *optval, unsigned int optlen);
 697int compat_ip_getsockopt(struct sock *sk, int level, int optname,
 698                         char __user *optval, int __user *optlen);
 699int ip_ra_control(struct sock *sk, unsigned char on,
 700                  void (*destructor)(struct sock *));
 701
 702int ip_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len);
 703void ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err, __be16 port,
 704                   u32 info, u8 *payload);
 705void ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 dport,
 706                    u32 info);
 707
 708static inline void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb)
 709{
 710        ip_cmsg_recv_offset(msg, skb->sk, skb, 0, 0);
 711}
 712
 713bool icmp_global_allow(void);
 714extern int sysctl_icmp_msgs_per_sec;
 715extern int sysctl_icmp_msgs_burst;
 716
 717#ifdef CONFIG_PROC_FS
 718int ip_misc_proc_init(void);
 719#endif
 720
 721int rtm_getroute_parse_ip_proto(struct nlattr *attr, u8 *ip_proto, u8 family,
 722                                struct netlink_ext_ack *extack);
 723
 724#endif  /* _IP_H */
 725