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 extern unsigned int sysctl_fib_sync_mem;
  42 extern unsigned int sysctl_fib_sync_mem_min;
  43 extern unsigned int sysctl_fib_sync_mem_max;
  44
  45 struct sock;
  46
  47 struct 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
  61         u16                     frag_max_size;
  62 };
  63
  64 static inline bool ipv4_l3mdev_skb(u16 flags)
  65 {
  66         return !!(flags & IPSKB_L3SLAVE);
  67 }
  68
  69 static inline unsigned int ip_hdrlen(const struct sk_buff *skb)
  70 {
  71         return ip_hdr(skb)->ihl * 4;
  72 }
  73
  74 struct ipcm_cookie {
  75         struct sockcm_cookie    sockc;
  76         __be32                  addr;
  77         int                     oif;
  78         struct ip_options_rcu   *opt;
  79         __u8                    ttl;
  80         __s16                   tos;
  81         char                    priority;
  82         __u16                   gso_size;
  83 };
  84
  85 static inline void ipcm_init(struct ipcm_cookie *ipcm)
  86 {
  87         *ipcm = (struct ipcm_cookie) { .tos = -1 };
  88 }
  89
  90 static inline void ipcm_init_sk(struct ipcm_cookie *ipcm,
  91                                 const struct inet_sock *inet)
  92 {
  93         ipcm_init(ipcm);
  94
  95         ipcm->sockc.tsflags = inet->sk.sk_tsflags;
  96         ipcm->oif = inet->sk.sk_bound_dev_if;
  97         ipcm->addr = inet->inet_saddr;
  98 }
  99
 100 #define IPCB(skb) ((struct inet_skb_parm*)((skb)->cb))
 101 #define PKTINFO_SKB_CB(skb) ((struct in_pktinfo *)((skb)->cb))
 102
 103 /* return enslaved device index if relevant */
 104 static inline int inet_sdif(struct sk_buff *skb)
 105 {
 106 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
 107         if (skb && ipv4_l3mdev_skb(IPCB(skb)->flags))
 108                 return IPCB(skb)->iif;
 109 #endif
 110         return 0;
 111 }
 112
 113 /* Special input handler for packets caught by router alert option.
 114    They are selected only by protocol field, and then processed likely
 115    local ones; but only if someone wants them! Otherwise, router
 116    not running rsvpd will kill RSVP.
 117
 118    It is user level problem, what it will make with them.
 119    I have no idea, how it will masquearde or NAT them (it is joke, joke :-)),
 120    but receiver should be enough clever f.e. to forward mtrace requests,
 121    sent to multicast group to reach destination designated router.
 122  */
 123
 124 struct ip_ra_chain {
 125         struct ip_ra_chain __rcu *next;
 126         struct sock             *sk;
 127         union {
 128                 void                    (*destructor)(struct sock *);
 129                 struct sock             *saved_sk;
 130         };
 131         struct rcu_head         rcu;
 132 };
 133
 134 /* IP flags. */
 135 #define IP_CE           0x8000          /* Flag: "Congestion"           */
 136 #define IP_DF           0x4000          /* Flag: "Don't Fragment"       */
 137 #define IP_MF           0x2000          /* Flag: "More Fragments"       */
 138 #define IP_OFFSET       0x1FFF          /* "Fragment Offset" part       */
 139
 140 #define IP_FRAG_TIME    (30 * HZ)               /* fragment lifetime    */
 141
 142 struct msghdr;
 143 struct net_device;
 144 struct packet_type;
 145 struct rtable;
 146 struct sockaddr;
 147
 148 int igmp_mc_init(void);
 149
 150 /*
 151  *      Functions provided by ip.c
 152  */
 153
 154 int ip_build_and_send_pkt(struct sk_buff *skb, const struct sock *sk,
 155                           __be32 saddr, __be32 daddr,
 156                           struct ip_options_rcu *opt);
 157 int ip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt,
 158            struct net_device *orig_dev);
 159 void ip_list_rcv(struct list_head *head, struct packet_type *pt,
 160                  struct net_device *orig_dev);
 161 int ip_local_deliver(struct sk_buff *skb);
 162 void ip_protocol_deliver_rcu(struct net *net, struct sk_buff *skb, int proto);
 163 int ip_mr_input(struct sk_buff *skb);
 164 int ip_output(struct net *net, struct sock *sk, struct sk_buff *skb);
 165 int ip_mc_output(struct net *net, struct sock *sk, struct sk_buff *skb);
 166 int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
 167                    int (*output)(struct net *, struct sock *, struct sk_buff *));
 168 void ip_send_check(struct iphdr *ip);
 169 int __ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb);
 170 int ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb);
 171
 172 int __ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl,
 173                     __u8 tos);
 174 void ip_init(void);
 175 int ip_append_data(struct sock *sk, struct flowi4 *fl4,
 176                    int getfrag(void *from, char *to, int offset, int len,
 177                                int odd, struct sk_buff *skb),
 178                    void *from, int len, int protolen,
 179                    struct ipcm_cookie *ipc,
 180                    struct rtable **rt,
 181                    unsigned int flags);
 182 int ip_generic_getfrag(void *from, char *to, int offset, int len, int odd,
 183                        struct sk_buff *skb);
 184 ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,
 185                        int offset, size_t size, int flags);
 186 struct sk_buff *__ip_make_skb(struct sock *sk, struct flowi4 *fl4,
 187                               struct sk_buff_head *queue,
 188                               struct inet_cork *cork);
 189 int ip_send_skb(struct net *net, struct sk_buff *skb);
 190 int ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4);
 191 void ip_flush_pending_frames(struct sock *sk);
 192 struct sk_buff *ip_make_skb(struct sock *sk, struct flowi4 *fl4,
 193                             int getfrag(void *from, char *to, int offset,
 194                                         int len, int odd, struct sk_buff *skb),
 195                             void *from, int length, int transhdrlen,
 196                             struct ipcm_cookie *ipc, struct rtable **rtp,
 197                             struct inet_cork *cork, unsigned int flags);
 198
 199 static inline int ip_queue_xmit(struct sock *sk, struct sk_buff *skb,
 200                                 struct flowi *fl)
 201 {
 202         return __ip_queue_xmit(sk, skb, fl, inet_sk(sk)->tos);
 203 }
 204
 205 static inline struct sk_buff *ip_finish_skb(struct sock *sk, struct flowi4 *fl4)
 206 {
 207         return __ip_make_skb(sk, fl4, &sk->sk_write_queue, &inet_sk(sk)->cork.base);
 208 }
 209
 210 static inline __u8 get_rttos(struct ipcm_cookie* ipc, struct inet_sock *inet)
 211 {
 212         return (ipc->tos != -1) ? RT_TOS(ipc->tos) : RT_TOS(inet->tos);
 213 }
 214
 215 static inline __u8 get_rtconn_flags(struct ipcm_cookie* ipc, struct sock* sk)
 216 {
 217         return (ipc->tos != -1) ? RT_CONN_FLAGS_TOS(sk, ipc->tos) : RT_CONN_FLAGS(sk);
 218 }
 219
 220 /* datagram.c */
 221 int __ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
 222 int ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
 223
 224 void ip4_datagram_release_cb(struct sock *sk);
 225
 226 struct ip_reply_arg {
 227         struct kvec iov[1];
 228         int         flags;
 229         __wsum      csum;
 230         int         csumoffset; /* u16 offset of csum in iov[0].iov_base */
 231                                 /* -1 if not needed */
 232         int         bound_dev_if;
 233         u8          tos;
 234         kuid_t      uid;
 235 };
 236
 237 #define IP_REPLY_ARG_NOSRCCHECK 1
 238
 239 static inline __u8 ip_reply_arg_flowi_flags(const struct ip_reply_arg *arg)
 240 {
 241         return (arg->flags & IP_REPLY_ARG_NOSRCCHECK) ? FLOWI_FLAG_ANYSRC : 0;
 242 }
 243
 244 void ip_send_unicast_reply(struct sock *sk, struct sk_buff *skb,
 245                            const struct ip_options *sopt,
 246                            __be32 daddr, __be32 saddr,
 247                            const struct ip_reply_arg *arg,
 248                            unsigned int len);
 249
 250 #define IP_INC_STATS(net, field)        SNMP_INC_STATS64((net)->mib.ip_statistics, field)
 251 #define __IP_INC_STATS(net, field)      __SNMP_INC_STATS64((net)->mib.ip_statistics, field)
 252 #define IP_ADD_STATS(net, field, val)   SNMP_ADD_STATS64((net)->mib.ip_statistics, field, val)
 253 #define __IP_ADD_STATS(net, field, val) __SNMP_ADD_STATS64((net)->mib.ip_statistics, field, val)
 254 #define IP_UPD_PO_STATS(net, field, val) SNMP_UPD_PO_STATS64((net)->mib.ip_statistics, field, val)
 255 #define __IP_UPD_PO_STATS(net, field, val) __SNMP_UPD_PO_STATS64((net)->mib.ip_statistics, field, val)
 256 #define NET_INC_STATS(net, field)       SNMP_INC_STATS((net)->mib.net_statistics, field)
 257 #define __NET_INC_STATS(net, field)     __SNMP_INC_STATS((net)->mib.net_statistics, field)
 258 #define NET_ADD_STATS(net, field, adnd) SNMP_ADD_STATS((net)->mib.net_statistics, field, adnd)
 259 #define __NET_ADD_STATS(net, field, adnd) __SNMP_ADD_STATS((net)->mib.net_statistics, field, adnd)
 260
 261 u64 snmp_get_cpu_field(void __percpu *mib, int cpu, int offct);
 262 unsigned long snmp_fold_field(void __percpu *mib, int offt);
 263 #if BITS_PER_LONG==32
 264 u64 snmp_get_cpu_field64(void __percpu *mib, int cpu, int offct,
 265                          size_t syncp_offset);
 266 u64 snmp_fold_field64(void __percpu *mib, int offt, size_t sync_off);
 267 #else
 268 static inline u64  snmp_get_cpu_field64(void __percpu *mib, int cpu, int offct,
 269                                         size_t syncp_offset)
 270 {
 271         return snmp_get_cpu_field(mib, cpu, offct);
 272
 273 }
 274
 275 static inline u64 snmp_fold_field64(void __percpu *mib, int offt, size_t syncp_off)
 276 {
 277         return snmp_fold_field(mib, offt);
 278 }
 279 #endif
 280
 281 #define snmp_get_cpu_field64_batch(buff64, stats_list, mib_statistic, offset) \
 282 { \
 283         int i, c; \
 284         for_each_possible_cpu(c) { \
 285                 for (i = 0; stats_list[i].name; i++) \
 286                         buff64[i] += snmp_get_cpu_field64( \
 287                                         mib_statistic, \
 288                                         c, stats_list[i].entry, \
 289                                         offset); \
 290         } \
 291 }
 292
 293 #define snmp_get_cpu_field_batch(buff, stats_list, mib_statistic) \
 294 { \
 295         int i, c; \
 296         for_each_possible_cpu(c) { \
 297                 for (i = 0; stats_list[i].name; i++) \
 298                         buff[i] += snmp_get_cpu_field( \
 299                                                 mib_statistic, \
 300                                                 c, stats_list[i].entry); \
 301         } \
 302 }
 303
 304 void inet_get_local_port_range(struct net *net, int *low, int *high);
 305
 306 #ifdef CONFIG_SYSCTL
 307 static inline int inet_is_local_reserved_port(struct net *net, int port)
 308 {
 309         if (!net->ipv4.sysctl_local_reserved_ports)
 310                 return 0;
 311         return test_bit(port, net->ipv4.sysctl_local_reserved_ports);
 312 }
 313
 314 static inline bool sysctl_dev_name_is_allowed(const char *name)
 315 {
 316         return strcmp(name, "default") != 0  && strcmp(name, "all") != 0;
 317 }
 318
 319 static inline int inet_prot_sock(struct net *net)
 320 {
 321         return net->ipv4.sysctl_ip_prot_sock;
 322 }
 323
 324 #else
 325 static inline int inet_is_local_reserved_port(struct net *net, int port)
 326 {
 327         return 0;
 328 }
 329
 330 static inline int inet_prot_sock(struct net *net)
 331 {
 332         return PROT_SOCK;
 333 }
 334 #endif
 335
 336 __be32 inet_current_timestamp(void);
 337
 338 /* From inetpeer.c */
 339 extern int inet_peer_threshold;
 340 extern int inet_peer_minttl;
 341 extern int inet_peer_maxttl;
 342
 343 void ipfrag_init(void);
 344
 345 void ip_static_sysctl_init(void);
 346
 347 #define IP4_REPLY_MARK(net, mark) \
 348         ((net)->ipv4.sysctl_fwmark_reflect ? (mark) : 0)
 349
 350 static inline bool ip_is_fragment(const struct iphdr *iph)
 351 {
 352         return (iph->frag_off & htons(IP_MF | IP_OFFSET)) != 0;
 353 }
 354
 355 #ifdef CONFIG_INET
 356 #include <net/dst.h>
 357
 358 /* The function in 2.2 was invalid, producing wrong result for
 359  * check=0xFEFF. It was noticed by Arthur Skawina _year_ ago. --ANK(000625) */
 360 static inline
 361 int ip_decrease_ttl(struct iphdr *iph)
 362 {
 363         u32 check = (__force u32)iph->check;
 364         check += (__force u32)htons(0x0100);
 365         iph->check = (__force __sum16)(check + (check>=0xFFFF));
 366         return --iph->ttl;
 367 }
 368
 369 static inline int ip_mtu_locked(const struct dst_entry *dst)
 370 {
 371         const struct rtable *rt = (const struct rtable *)dst;
 372
 373         return rt->rt_mtu_locked || dst_metric_locked(dst, RTAX_MTU);
 374 }
 375
 376 static inline
 377 int ip_dont_fragment(const struct sock *sk, const struct dst_entry *dst)
 378 {
 379         u8 pmtudisc = READ_ONCE(inet_sk(sk)->pmtudisc);
 380
 381         return  pmtudisc == IP_PMTUDISC_DO ||
 382                 (pmtudisc == IP_PMTUDISC_WANT &&
 383                  !ip_mtu_locked(dst));
 384 }
 385
 386 static inline bool ip_sk_accept_pmtu(const struct sock *sk)
 387 {
 388         return inet_sk(sk)->pmtudisc != IP_PMTUDISC_INTERFACE &&
 389                inet_sk(sk)->pmtudisc != IP_PMTUDISC_OMIT;
 390 }
 391
 392 static inline bool ip_sk_use_pmtu(const struct sock *sk)
 393 {
 394         return inet_sk(sk)->pmtudisc < IP_PMTUDISC_PROBE;
 395 }
 396
 397 static inline bool ip_sk_ignore_df(const struct sock *sk)
 398 {
 399         return inet_sk(sk)->pmtudisc < IP_PMTUDISC_DO ||
 400                inet_sk(sk)->pmtudisc == IP_PMTUDISC_OMIT;
 401 }
 402
 403 static inline unsigned int ip_dst_mtu_maybe_forward(const struct dst_entry *dst,
 404                                                     bool forwarding)
 405 {
 406         struct net *net = dev_net(dst->dev);
 407
 408         if (net->ipv4.sysctl_ip_fwd_use_pmtu ||
 409             ip_mtu_locked(dst) ||
 410             !forwarding)
 411                 return dst_mtu(dst);
 412
 413         return min(READ_ONCE(dst->dev->mtu), IP_MAX_MTU);
 414 }
 415
 416 static inline unsigned int ip_skb_dst_mtu(struct sock *sk,
 417                                           const struct sk_buff *skb)
 418 {
 419         if (!sk || !sk_fullsock(sk) || ip_sk_use_pmtu(sk)) {
 420                 bool forwarding = IPCB(skb)->flags & IPSKB_FORWARDED;
 421
 422                 return ip_dst_mtu_maybe_forward(skb_dst(skb), forwarding);
 423         }
 424
 425         return min(READ_ONCE(skb_dst(skb)->dev->mtu), IP_MAX_MTU);
 426 }
 427
 428 struct dst_metrics *ip_fib_metrics_init(struct net *net, struct nlattr *fc_mx,
 429                                         int fc_mx_len,
 430                                         struct netlink_ext_ack *extack);
 431 static inline void ip_fib_metrics_put(struct dst_metrics *fib_metrics)
 432 {
 433         if (fib_metrics != &dst_default_metrics &&
 434             refcount_dec_and_test(&fib_metrics->refcnt))
 435                 kfree(fib_metrics);
 436 }
 437
 438 /* ipv4 and ipv6 both use refcounted metrics if it is not the default */
 439 static inline
 440 void ip_dst_init_metrics(struct dst_entry *dst, struct dst_metrics *fib_metrics)
 441 {
 442         dst_init_metrics(dst, fib_metrics->metrics, true);
 443
 444         if (fib_metrics != &dst_default_metrics) {
 445                 dst->_metrics |= DST_METRICS_REFCOUNTED;
 446                 refcount_inc(&fib_metrics->refcnt);
 447         }
 448 }
 449
 450 static inline
 451 void ip_dst_metrics_put(struct dst_entry *dst)
 452 {
 453         struct dst_metrics *p = (struct dst_metrics *)DST_METRICS_PTR(dst);
 454
 455         if (p != &dst_default_metrics && refcount_dec_and_test(&p->refcnt))
 456                 kfree(p);
 457 }
 458
 459 u32 ip_idents_reserve(u32 hash, int segs);
 460 void __ip_select_ident(struct net *net, struct iphdr *iph, int segs);
 461
 462 static inline void ip_select_ident_segs(struct net *net, struct sk_buff *skb,
 463                                         struct sock *sk, int segs)
 464 {
 465         struct iphdr *iph = ip_hdr(skb);
 466
 467         if ((iph->frag_off & htons(IP_DF)) && !skb->ignore_df) {
 468                 /* This is only to work around buggy Windows95/2000
 469                  * VJ compression implementations.  If the ID field
 470                  * does not change, they drop every other packet in
 471                  * a TCP stream using header compression.
 472                  */
 473                 if (sk && inet_sk(sk)->inet_daddr) {
 474                         iph->id = htons(inet_sk(sk)->inet_id);
 475                         inet_sk(sk)->inet_id += segs;
 476                 } else {
 477                         iph->id = 0;
 478                 }
 479         } else {
 480                 __ip_select_ident(net, iph, segs);
 481         }
 482 }
 483
 484 static inline void ip_select_ident(struct net *net, struct sk_buff *skb,
 485                                    struct sock *sk)
 486 {
 487         ip_select_ident_segs(net, skb, sk, 1);
 488 }
 489
 490 static inline __wsum inet_compute_pseudo(struct sk_buff *skb, int proto)
 491 {
 492         return csum_tcpudp_nofold(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
 493                                   skb->len, proto, 0);
 494 }
 495
 496 /* copy IPv4 saddr & daddr to flow_keys, possibly using 64bit load/store
 497  * Equivalent to :      flow->v4addrs.src = iph->saddr;
 498  *                      flow->v4addrs.dst = iph->daddr;
 499  */
 500 static inline void iph_to_flow_copy_v4addrs(struct flow_keys *flow,
 501                                             const struct iphdr *iph)
 502 {
 503         BUILD_BUG_ON(offsetof(typeof(flow->addrs), v4addrs.dst) !=
 504                      offsetof(typeof(flow->addrs), v4addrs.src) +
 505                               sizeof(flow->addrs.v4addrs.src));
 506         memcpy(&flow->addrs.v4addrs, &iph->saddr, sizeof(flow->addrs.v4addrs));
 507         flow->control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
 508 }
 509
 510 static inline __wsum inet_gro_compute_pseudo(struct sk_buff *skb, int proto)
 511 {
 512         const struct iphdr *iph = skb_gro_network_header(skb);
 513
 514         return csum_tcpudp_nofold(iph->saddr, iph->daddr,
 515                                   skb_gro_len(skb), proto, 0);
 516 }
 517
 518 /*
 519  *      Map a multicast IP onto multicast MAC for type ethernet.
 520  */
 521
 522 static inline void ip_eth_mc_map(__be32 naddr, char *buf)
 523 {
 524         __u32 addr=ntohl(naddr);
 525         buf[0]=0x01;
 526         buf[1]=0x00;
 527         buf[2]=0x5e;
 528         buf[5]=addr&0xFF;
 529         addr>>=8;
 530         buf[4]=addr&0xFF;
 531         addr>>=8;
 532         buf[3]=addr&0x7F;
 533 }
 534
 535 /*
 536  *      Map a multicast IP onto multicast MAC for type IP-over-InfiniBand.
 537  *      Leave P_Key as 0 to be filled in by driver.
 538  */
 539
 540 static inline void ip_ib_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
 541 {
 542         __u32 addr;
 543         unsigned char scope = broadcast[5] & 0xF;
 544
 545         buf[0]  = 0;            /* Reserved */
 546         buf[1]  = 0xff;         /* Multicast QPN */
 547         buf[2]  = 0xff;
 548         buf[3]  = 0xff;
 549         addr    = ntohl(naddr);
 550         buf[4]  = 0xff;
 551         buf[5]  = 0x10 | scope; /* scope from broadcast address */
 552         buf[6]  = 0x40;         /* IPv4 signature */
 553         buf[7]  = 0x1b;
 554         buf[8]  = broadcast[8];         /* P_Key */
 555         buf[9]  = broadcast[9];
 556         buf[10] = 0;
 557         buf[11] = 0;
 558         buf[12] = 0;
 559         buf[13] = 0;
 560         buf[14] = 0;
 561         buf[15] = 0;
 562         buf[19] = addr & 0xff;
 563         addr  >>= 8;
 564         buf[18] = addr & 0xff;
 565         addr  >>= 8;
 566         buf[17] = addr & 0xff;
 567         addr  >>= 8;
 568         buf[16] = addr & 0x0f;
 569 }
 570
 571 static inline void ip_ipgre_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
 572 {
 573         if ((broadcast[0] | broadcast[1] | broadcast[2] | broadcast[3]) != 0)
 574                 memcpy(buf, broadcast, 4);
 575         else
 576                 memcpy(buf, &naddr, sizeof(naddr));
 577 }
 578
 579 #if IS_ENABLED(CONFIG_IPV6)
 580 #include <linux/ipv6.h>
 581 #endif
 582
 583 static __inline__ void inet_reset_saddr(struct sock *sk)
 584 {
 585         inet_sk(sk)->inet_rcv_saddr = inet_sk(sk)->inet_saddr = 0;
 586 #if IS_ENABLED(CONFIG_IPV6)
 587         if (sk->sk_family == PF_INET6) {
 588                 struct ipv6_pinfo *np = inet6_sk(sk);
 589
 590                 memset(&np->saddr, 0, sizeof(np->saddr));
 591                 memset(&sk->sk_v6_rcv_saddr, 0, sizeof(sk->sk_v6_rcv_saddr));
 592         }
 593 #endif
 594 }
 595
 596 #endif
 597
 598 static inline unsigned int ipv4_addr_hash(__be32 ip)
 599 {
 600         return (__force unsigned int) ip;
 601 }
 602
 603 static inline u32 ipv4_portaddr_hash(const struct net *net,
 604                                      __be32 saddr,
 605                                      unsigned int port)
 606 {
 607         return jhash_1word((__force u32)saddr, net_hash_mix(net)) ^ port;
 608 }
 609
 610 bool ip_call_ra_chain(struct sk_buff *skb);
 611
 612 /*
 613  *      Functions provided by ip_fragment.c
 614  */
 615
 616 enum ip_defrag_users {
 617         IP_DEFRAG_LOCAL_DELIVER,
 618         IP_DEFRAG_CALL_RA_CHAIN,
 619         IP_DEFRAG_CONNTRACK_IN,
 620         __IP_DEFRAG_CONNTRACK_IN_END    = IP_DEFRAG_CONNTRACK_IN + USHRT_MAX,
 621         IP_DEFRAG_CONNTRACK_OUT,
 622         __IP_DEFRAG_CONNTRACK_OUT_END   = IP_DEFRAG_CONNTRACK_OUT + USHRT_MAX,
 623         IP_DEFRAG_CONNTRACK_BRIDGE_IN,
 624         __IP_DEFRAG_CONNTRACK_BRIDGE_IN = IP_DEFRAG_CONNTRACK_BRIDGE_IN + USHRT_MAX,
 625         IP_DEFRAG_VS_IN,
 626         IP_DEFRAG_VS_OUT,
 627         IP_DEFRAG_VS_FWD,
 628         IP_DEFRAG_AF_PACKET,
 629         IP_DEFRAG_MACVLAN,
 630 };
 631
 632 /* Return true if the value of 'user' is between 'lower_bond'
 633  * and 'upper_bond' inclusively.
 634  */
 635 static inline bool ip_defrag_user_in_between(u32 user,
 636                                              enum ip_defrag_users lower_bond,
 637                                              enum ip_defrag_users upper_bond)
 638 {
 639         return user >= lower_bond && user <= upper_bond;
 640 }
 641
 642 int ip_defrag(struct net *net, struct sk_buff *skb, u32 user);
 643 #ifdef CONFIG_INET
 644 struct sk_buff *ip_check_defrag(struct net *net, struct sk_buff *skb, u32 user);
 645 #else
 646 static inline struct sk_buff *ip_check_defrag(struct net *net, struct sk_buff *skb, u32 user)
 647 {
 648         return skb;
 649 }
 650 #endif
 651
 652 /*
 653  *      Functions provided by ip_forward.c
 654  */
 655
 656 int ip_forward(struct sk_buff *skb);
 657
 658 /*
 659  *      Functions provided by ip_options.c
 660  */
 661
 662 void ip_options_build(struct sk_buff *skb, struct ip_options *opt,
 663                       __be32 daddr, struct rtable *rt, int is_frag);
 664
 665 int __ip_options_echo(struct net *net, struct ip_options *dopt,
 666                       struct sk_buff *skb, const struct ip_options *sopt);
 667 static inline int ip_options_echo(struct net *net, struct ip_options *dopt,
 668                                   struct sk_buff *skb)
 669 {
 670         return __ip_options_echo(net, dopt, skb, &IPCB(skb)->opt);
 671 }
 672
 673 void ip_options_fragment(struct sk_buff *skb);
 674 int __ip_options_compile(struct net *net, struct ip_options *opt,
 675                          struct sk_buff *skb, __be32 *info);
 676 int ip_options_compile(struct net *net, struct ip_options *opt,
 677                        struct sk_buff *skb);
 678 int ip_options_get(struct net *net, struct ip_options_rcu **optp,
 679                    unsigned char *data, int optlen);
 680 int ip_options_get_from_user(struct net *net, struct ip_options_rcu **optp,
 681                              unsigned char __user *data, int optlen);
 682 void ip_options_undo(struct ip_options *opt);
 683 void ip_forward_options(struct sk_buff *skb);
 684 int ip_options_rcv_srr(struct sk_buff *skb, struct net_device *dev);
 685
 686 /*
 687  *      Functions provided by ip_sockglue.c
 688  */
 689
 690 void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb);
 691 void ip_cmsg_recv_offset(struct msghdr *msg, struct sock *sk,
 692                          struct sk_buff *skb, int tlen, int offset);
 693 int ip_cmsg_send(struct sock *sk, struct msghdr *msg,
 694                  struct ipcm_cookie *ipc, bool allow_ipv6);
 695 int ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
 696                   unsigned int optlen);
 697 int ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
 698                   int __user *optlen);
 699 int compat_ip_setsockopt(struct sock *sk, int level, int optname,
 700                          char __user *optval, unsigned int optlen);
 701 int compat_ip_getsockopt(struct sock *sk, int level, int optname,
 702                          char __user *optval, int __user *optlen);
 703 int ip_ra_control(struct sock *sk, unsigned char on,
 704                   void (*destructor)(struct sock *));
 705
 706 int ip_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len);
 707 void ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err, __be16 port,
 708                    u32 info, u8 *payload);
 709 void ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 dport,
 710                     u32 info);
 711
 712 static inline void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb)
 713 {
 714         ip_cmsg_recv_offset(msg, skb->sk, skb, 0, 0);
 715 }
 716
 717 bool icmp_global_allow(void);
 718 extern int sysctl_icmp_msgs_per_sec;
 719 extern int sysctl_icmp_msgs_burst;
 720
 721 #ifdef CONFIG_PROC_FS
 722 int ip_misc_proc_init(void);
 723 #endif
 724
 725 int rtm_getroute_parse_ip_proto(struct nlattr *attr, u8 *ip_proto, u8 family,
 726                                 struct netlink_ext_ack *extack);
 727
 728 #endif  /* _IP_H */