include/net/ip.h

   1 /*
   2  * INET         An implementation of the TCP/IP protocol suite for the LINUX
   3  *              operating system.  INET is implemented using the  BSD Socket
   4  *              interface as the means of communication with the user level.
   5  *
   6  *              Definitions for the IP module.
   7  *
   8  * Version:     @(#)ip.h        1.0.2   05/07/93
   9  *
  10  * Authors:     Ross Biro
  11  *              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
  12  *              Alan Cox, <gw4pts@gw4pts.ampr.org>
  13  *
  14  * Changes:
  15  *              Mike McLagan    :       Routing by source
  16  *
  17  *              This program is free software; you can redistribute it and/or
  18  *              modify it under the terms of the GNU General Public License
  19  *              as published by the Free Software Foundation; either version
  20  *              2 of the License, or (at your option) any later version.
  21  */
  22 #ifndef _IP_H
  23 #define _IP_H
  24
  25 #include <linux/types.h>
  26 #include <linux/ip.h>
  27 #include <linux/in.h>
  28 #include <linux/skbuff.h>
  29 #include <linux/jhash.h>
  30
  31 #include <net/inet_sock.h>
  32 #include <net/route.h>
  33 #include <net/snmp.h>
  34 #include <net/flow.h>
  35 #include <net/flow_dissector.h>
  36 #include <net/netns/hash.h>
  37
  38 #define IPV4_MAX_PMTU           65535U          /* RFC 2675, Section 5.1 */
  39 #define IPV4_MIN_MTU            68                      /* RFC 791 */
  40
  41 struct sock;
  42
  43 struct 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
  60 static inline bool ipv4_l3mdev_skb(u16 flags)
  61 {
  62         return !!(flags & IPSKB_L3SLAVE);
  63 }
  64
  65 static inline unsigned int ip_hdrlen(const struct sk_buff *skb)
  66 {
  67         return ip_hdr(skb)->ihl * 4;
  68 }
  69
  70 struct 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
  81 static inline void ipcm_init(struct ipcm_cookie *ipcm)
  82 {
  83         *ipcm = (struct ipcm_cookie) { .tos = -1 };
  84 }
  85
  86 static 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 */
 100 static 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
 120 struct 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
 138 struct msghdr;
 139 struct net_device;
 140 struct packet_type;
 141 struct rtable;
 142 struct sockaddr;
 143
 144 int igmp_mc_init(void);
 145
 146 /*
 147  *      Functions provided by ip.c
 148  */
 149
 150 int ip_build_and_send_pkt(struct sk_buff *skb, const struct sock *sk,
 151                           __be32 saddr, __be32 daddr,
 152                           struct ip_options_rcu *opt);
 153 int ip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt,
 154            struct net_device *orig_dev);
 155 void ip_list_rcv(struct list_head *head, struct packet_type *pt,
 156                  struct net_device *orig_dev);
 157 int ip_local_deliver(struct sk_buff *skb);
 158 void ip_protocol_deliver_rcu(struct net *net, struct sk_buff *skb, int proto);
 159 int ip_mr_input(struct sk_buff *skb);
 160 int ip_output(struct net *net, struct sock *sk, struct sk_buff *skb);
 161 int ip_mc_output(struct net *net, struct sock *sk, struct sk_buff *skb);
 162 int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
 163                    int (*output)(struct net *, struct sock *, struct sk_buff *));
 164 void ip_send_check(struct iphdr *ip);
 165 int __ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb);
 166 int ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb);
 167
 168 int __ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl,
 169                     __u8 tos);
 170 void ip_init(void);
 171 int 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);
 178 int ip_generic_getfrag(void *from, char *to, int offset, int len, int odd,
 179                        struct sk_buff *skb);
 180 ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,
 181                        int offset, size_t size, int flags);
 182 struct sk_buff *__ip_make_skb(struct sock *sk, struct flowi4 *fl4,
 183                               struct sk_buff_head *queue,
 184                               struct inet_cork *cork);
 185 int ip_send_skb(struct net *net, struct sk_buff *skb);
 186 int ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4);
 187 void ip_flush_pending_frames(struct sock *sk);
 188 struct 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
 195 static 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
 201 static 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
 206 static 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
 211 static 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 */
 217 int __ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
 218 int ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
 219
 220 void ip4_datagram_release_cb(struct sock *sk);
 221
 222 struct 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
 235 static 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
 240 void 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
 257 u64 snmp_get_cpu_field(void __percpu *mib, int cpu, int offct);
 258 unsigned long snmp_fold_field(void __percpu *mib, int offt);
 259 #if BITS_PER_LONG==32
 260 u64 snmp_get_cpu_field64(void __percpu *mib, int cpu, int offct,
 261                          size_t syncp_offset);
 262 u64 snmp_fold_field64(void __percpu *mib, int offt, size_t sync_off);
 263 #else
 264 static 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
 271 static 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
 300 void inet_get_local_port_range(struct net *net, int *low, int *high);
 301
 302 #ifdef CONFIG_SYSCTL
 303 static 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
 310 static inline bool sysctl_dev_name_is_allowed(const char *name)
 311 {
 312         return strcmp(name, "default") != 0  && strcmp(name, "all") != 0;
 313 }
 314
 315 static inline int inet_prot_sock(struct net *net)
 316 {
 317         return net->ipv4.sysctl_ip_prot_sock;
 318 }
 319
 320 #else
 321 static inline int inet_is_local_reserved_port(struct net *net, int port)
 322 {
 323         return 0;
 324 }
 325
 326 static 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 */
 335 extern int inet_peer_threshold;
 336 extern int inet_peer_minttl;
 337 extern int inet_peer_maxttl;
 338
 339 void ipfrag_init(void);
 340
 341 void ip_static_sysctl_init(void);
 342
 343 #define IP4_REPLY_MARK(net, mark) \
 344         ((net)->ipv4.sysctl_fwmark_reflect ? (mark) : 0)
 345
 346 static 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) */
 356 static inline
 357 int 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
 365 static 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
 372 static inline
 373 int 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
 382 static 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
 388 static inline bool ip_sk_use_pmtu(const struct sock *sk)
 389 {
 390         return inet_sk(sk)->pmtudisc < IP_PMTUDISC_PROBE;
 391 }
 392
 393 static 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
 399 static 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
 412 static 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
 424 struct dst_metrics *ip_fib_metrics_init(struct net *net, struct nlattr *fc_mx,
 425                                         int fc_mx_len,
 426                                         struct netlink_ext_ack *extack);
 427 static 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 */
 435 static inline
 436 void 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
 446 static inline
 447 void 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
 455 u32 ip_idents_reserve(u32 hash, int segs);
 456 void __ip_select_ident(struct net *net, struct iphdr *iph, int segs);
 457
 458 static 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
 480 static 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
 486 static 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  */
 496 static 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
 506 static 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
 518 static 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
 536 static 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
 567 static 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
 579 static __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
 594 static inline unsigned int ipv4_addr_hash(__be32 ip)
 595 {
 596         return (__force unsigned int) ip;
 597 }
 598
 599 static 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
 606 bool ip_call_ra_chain(struct sk_buff *skb);
 607
 608 /*
 609  *      Functions provided by ip_fragment.c
 610  */
 611
 612 enum 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  */
 631 static 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
 638 int ip_defrag(struct net *net, struct sk_buff *skb, u32 user);
 639 #ifdef CONFIG_INET
 640 struct sk_buff *ip_check_defrag(struct net *net, struct sk_buff *skb, u32 user);
 641 #else
 642 static 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
 652 int ip_forward(struct sk_buff *skb);
 653
 654 /*
 655  *      Functions provided by ip_options.c
 656  */
 657
 658 void ip_options_build(struct sk_buff *skb, struct ip_options *opt,
 659                       __be32 daddr, struct rtable *rt, int is_frag);
 660
 661 int __ip_options_echo(struct net *net, struct ip_options *dopt,
 662                       struct sk_buff *skb, const struct ip_options *sopt);
 663 static 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
 669 void ip_options_fragment(struct sk_buff *skb);
 670 int __ip_options_compile(struct net *net, struct ip_options *opt,
 671                          struct sk_buff *skb, __be32 *info);
 672 int ip_options_compile(struct net *net, struct ip_options *opt,
 673                        struct sk_buff *skb);
 674 int ip_options_get(struct net *net, struct ip_options_rcu **optp,
 675                    unsigned char *data, int optlen);
 676 int ip_options_get_from_user(struct net *net, struct ip_options_rcu **optp,
 677                              unsigned char __user *data, int optlen);
 678 void ip_options_undo(struct ip_options *opt);
 679 void ip_forward_options(struct sk_buff *skb);
 680 int ip_options_rcv_srr(struct sk_buff *skb);
 681
 682 /*
 683  *      Functions provided by ip_sockglue.c
 684  */
 685
 686 void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb);
 687 void ip_cmsg_recv_offset(struct msghdr *msg, struct sock *sk,
 688                          struct sk_buff *skb, int tlen, int offset);
 689 int ip_cmsg_send(struct sock *sk, struct msghdr *msg,
 690                  struct ipcm_cookie *ipc, bool allow_ipv6);
 691 int ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
 692                   unsigned int optlen);
 693 int ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
 694                   int __user *optlen);
 695 int compat_ip_setsockopt(struct sock *sk, int level, int optname,
 696                          char __user *optval, unsigned int optlen);
 697 int compat_ip_getsockopt(struct sock *sk, int level, int optname,
 698                          char __user *optval, int __user *optlen);
 699 int ip_ra_control(struct sock *sk, unsigned char on,
 700                   void (*destructor)(struct sock *));
 701
 702 int ip_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len);
 703 void ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err, __be16 port,
 704                    u32 info, u8 *payload);
 705 void ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 dport,
 706                     u32 info);
 707
 708 static 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
 713 bool icmp_global_allow(void);
 714 extern int sysctl_icmp_msgs_per_sec;
 715 extern int sysctl_icmp_msgs_burst;
 716
 717 #ifdef CONFIG_PROC_FS
 718 int ip_misc_proc_init(void);
 719 #endif
 720
 721 int rtm_getroute_parse_ip_proto(struct nlattr *attr, u8 *ip_proto, u8 family,
 722                                 struct netlink_ext_ack *extack);
 723
 724 #endif  /* _IP_H */