linux/include/net/ip.h
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   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
  30#include <net/inet_sock.h>
  31#include <net/route.h>
  32#include <net/snmp.h>
  33#include <net/flow.h>
  34
  35struct sock;
  36
  37struct inet_skb_parm {
  38        struct ip_options       opt;            /* Compiled IP options          */
  39        unsigned char           flags;
  40
  41#define IPSKB_FORWARDED         1
  42#define IPSKB_XFRM_TUNNEL_SIZE  2
  43#define IPSKB_XFRM_TRANSFORMED  4
  44#define IPSKB_FRAG_COMPLETE     8
  45#define IPSKB_REROUTED          16
  46
  47        u16                     frag_max_size;
  48};
  49
  50static inline unsigned int ip_hdrlen(const struct sk_buff *skb)
  51{
  52        return ip_hdr(skb)->ihl * 4;
  53}
  54
  55struct ipcm_cookie {
  56        __be32                  addr;
  57        int                     oif;
  58        struct ip_options_rcu   *opt;
  59        __u8                    tx_flags;
  60        __u8                    ttl;
  61        __s16                   tos;
  62        char                    priority;
  63};
  64
  65#define IPCB(skb) ((struct inet_skb_parm*)((skb)->cb))
  66#define PKTINFO_SKB_CB(skb) ((struct in_pktinfo *)((skb)->cb))
  67
  68struct ip_ra_chain {
  69        struct ip_ra_chain __rcu *next;
  70        struct sock             *sk;
  71        union {
  72                void                    (*destructor)(struct sock *);
  73                struct sock             *saved_sk;
  74        };
  75        struct rcu_head         rcu;
  76};
  77
  78extern struct ip_ra_chain __rcu *ip_ra_chain;
  79
  80/* IP flags. */
  81#define IP_CE           0x8000          /* Flag: "Congestion"           */
  82#define IP_DF           0x4000          /* Flag: "Don't Fragment"       */
  83#define IP_MF           0x2000          /* Flag: "More Fragments"       */
  84#define IP_OFFSET       0x1FFF          /* "Fragment Offset" part       */
  85
  86#define IP_FRAG_TIME    (30 * HZ)               /* fragment lifetime    */
  87
  88struct msghdr;
  89struct net_device;
  90struct packet_type;
  91struct rtable;
  92struct sockaddr;
  93
  94int igmp_mc_init(void);
  95
  96/*
  97 *      Functions provided by ip.c
  98 */
  99
 100int ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk,
 101                          __be32 saddr, __be32 daddr,
 102                          struct ip_options_rcu *opt);
 103int ip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt,
 104           struct net_device *orig_dev);
 105int ip_local_deliver(struct sk_buff *skb);
 106int ip_mr_input(struct sk_buff *skb);
 107int ip_output(struct sock *sk, struct sk_buff *skb);
 108int ip_mc_output(struct sock *sk, struct sk_buff *skb);
 109int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *));
 110int ip_do_nat(struct sk_buff *skb);
 111void ip_send_check(struct iphdr *ip);
 112int __ip_local_out(struct sk_buff *skb);
 113int ip_local_out_sk(struct sock *sk, struct sk_buff *skb);
 114static inline int ip_local_out(struct sk_buff *skb)
 115{
 116        return ip_local_out_sk(skb->sk, skb);
 117}
 118
 119int ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl);
 120void ip_init(void);
 121int ip_append_data(struct sock *sk, struct flowi4 *fl4,
 122                   int getfrag(void *from, char *to, int offset, int len,
 123                               int odd, struct sk_buff *skb),
 124                   void *from, int len, int protolen,
 125                   struct ipcm_cookie *ipc,
 126                   struct rtable **rt,
 127                   unsigned int flags);
 128int ip_generic_getfrag(void *from, char *to, int offset, int len, int odd,
 129                       struct sk_buff *skb);
 130ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,
 131                       int offset, size_t size, int flags);
 132struct sk_buff *__ip_make_skb(struct sock *sk, struct flowi4 *fl4,
 133                              struct sk_buff_head *queue,
 134                              struct inet_cork *cork);
 135int ip_send_skb(struct net *net, struct sk_buff *skb);
 136int ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4);
 137void ip_flush_pending_frames(struct sock *sk);
 138struct sk_buff *ip_make_skb(struct sock *sk, struct flowi4 *fl4,
 139                            int getfrag(void *from, char *to, int offset,
 140                                        int len, int odd, struct sk_buff *skb),
 141                            void *from, int length, int transhdrlen,
 142                            struct ipcm_cookie *ipc, struct rtable **rtp,
 143                            unsigned int flags);
 144
 145static inline struct sk_buff *ip_finish_skb(struct sock *sk, struct flowi4 *fl4)
 146{
 147        return __ip_make_skb(sk, fl4, &sk->sk_write_queue, &inet_sk(sk)->cork.base);
 148}
 149
 150static inline __u8 get_rttos(struct ipcm_cookie* ipc, struct inet_sock *inet)
 151{
 152        return (ipc->tos != -1) ? RT_TOS(ipc->tos) : RT_TOS(inet->tos);
 153}
 154
 155static inline __u8 get_rtconn_flags(struct ipcm_cookie* ipc, struct sock* sk)
 156{
 157        return (ipc->tos != -1) ? RT_CONN_FLAGS_TOS(sk, ipc->tos) : RT_CONN_FLAGS(sk);
 158}
 159
 160/* datagram.c */
 161int ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
 162
 163void ip4_datagram_release_cb(struct sock *sk);
 164
 165struct ip_reply_arg {
 166        struct kvec iov[1];   
 167        int         flags;
 168        __wsum      csum;
 169        int         csumoffset; /* u16 offset of csum in iov[0].iov_base */
 170                                /* -1 if not needed */ 
 171        int         bound_dev_if;
 172        u8          tos;
 173}; 
 174
 175#define IP_REPLY_ARG_NOSRCCHECK 1
 176
 177static inline __u8 ip_reply_arg_flowi_flags(const struct ip_reply_arg *arg)
 178{
 179        return (arg->flags & IP_REPLY_ARG_NOSRCCHECK) ? FLOWI_FLAG_ANYSRC : 0;
 180}
 181
 182void ip_send_unicast_reply(struct net *net, struct sk_buff *skb, __be32 daddr,
 183                           __be32 saddr, const struct ip_reply_arg *arg,
 184                           unsigned int len);
 185
 186#define IP_INC_STATS(net, field)        SNMP_INC_STATS64((net)->mib.ip_statistics, field)
 187#define IP_INC_STATS_BH(net, field)     SNMP_INC_STATS64_BH((net)->mib.ip_statistics, field)
 188#define IP_ADD_STATS(net, field, val)   SNMP_ADD_STATS64((net)->mib.ip_statistics, field, val)
 189#define IP_ADD_STATS_BH(net, field, val) SNMP_ADD_STATS64_BH((net)->mib.ip_statistics, field, val)
 190#define IP_UPD_PO_STATS(net, field, val) SNMP_UPD_PO_STATS64((net)->mib.ip_statistics, field, val)
 191#define IP_UPD_PO_STATS_BH(net, field, val) SNMP_UPD_PO_STATS64_BH((net)->mib.ip_statistics, field, val)
 192#define NET_INC_STATS(net, field)       SNMP_INC_STATS((net)->mib.net_statistics, field)
 193#define NET_INC_STATS_BH(net, field)    SNMP_INC_STATS_BH((net)->mib.net_statistics, field)
 194#define NET_INC_STATS_USER(net, field)  SNMP_INC_STATS_USER((net)->mib.net_statistics, field)
 195#define NET_ADD_STATS(net, field, adnd) SNMP_ADD_STATS((net)->mib.net_statistics, field, adnd)
 196#define NET_ADD_STATS_BH(net, field, adnd) SNMP_ADD_STATS_BH((net)->mib.net_statistics, field, adnd)
 197#define NET_ADD_STATS_USER(net, field, adnd) SNMP_ADD_STATS_USER((net)->mib.net_statistics, field, adnd)
 198
 199unsigned long snmp_fold_field(void __percpu *mib[], int offt);
 200#if BITS_PER_LONG==32
 201u64 snmp_fold_field64(void __percpu *mib[], int offt, size_t sync_off);
 202#else
 203static inline u64 snmp_fold_field64(void __percpu *mib[], int offt, size_t syncp_off)
 204{
 205        return snmp_fold_field(mib, offt);
 206}
 207#endif
 208int snmp_mib_init(void __percpu *ptr[2], size_t mibsize, size_t align);
 209
 210static inline void snmp_mib_free(void __percpu *ptr[SNMP_ARRAY_SZ])
 211{
 212        int i;
 213
 214        BUG_ON(ptr == NULL);
 215        for (i = 0; i < SNMP_ARRAY_SZ; i++) {
 216                free_percpu(ptr[i]);
 217                ptr[i] = NULL;
 218        }
 219}
 220
 221void inet_get_local_port_range(struct net *net, int *low, int *high);
 222
 223extern unsigned long *sysctl_local_reserved_ports;
 224static inline int inet_is_reserved_local_port(int port)
 225{
 226        return test_bit(port, sysctl_local_reserved_ports);
 227}
 228
 229extern int sysctl_ip_nonlocal_bind;
 230
 231/* From inetpeer.c */
 232extern int inet_peer_threshold;
 233extern int inet_peer_minttl;
 234extern int inet_peer_maxttl;
 235
 236/* From ip_input.c */
 237extern int sysctl_ip_early_demux;
 238
 239/* From ip_output.c */
 240extern int sysctl_ip_dynaddr;
 241
 242void ipfrag_init(void);
 243
 244void ip_static_sysctl_init(void);
 245
 246static inline bool ip_is_fragment(const struct iphdr *iph)
 247{
 248        return (iph->frag_off & htons(IP_MF | IP_OFFSET)) != 0;
 249}
 250
 251#ifdef CONFIG_INET
 252#include <net/dst.h>
 253
 254/* The function in 2.2 was invalid, producing wrong result for
 255 * check=0xFEFF. It was noticed by Arthur Skawina _year_ ago. --ANK(000625) */
 256static inline
 257int ip_decrease_ttl(struct iphdr *iph)
 258{
 259        u32 check = (__force u32)iph->check;
 260        check += (__force u32)htons(0x0100);
 261        iph->check = (__force __sum16)(check + (check>=0xFFFF));
 262        return --iph->ttl;
 263}
 264
 265static inline
 266int ip_dont_fragment(struct sock *sk, struct dst_entry *dst)
 267{
 268        return  inet_sk(sk)->pmtudisc == IP_PMTUDISC_DO ||
 269                (inet_sk(sk)->pmtudisc == IP_PMTUDISC_WANT &&
 270                 !(dst_metric_locked(dst, RTAX_MTU)));
 271}
 272
 273static inline bool ip_sk_accept_pmtu(const struct sock *sk)
 274{
 275        return inet_sk(sk)->pmtudisc != IP_PMTUDISC_INTERFACE &&
 276               inet_sk(sk)->pmtudisc != IP_PMTUDISC_OMIT;
 277}
 278
 279static inline bool ip_sk_use_pmtu(const struct sock *sk)
 280{
 281        return inet_sk(sk)->pmtudisc < IP_PMTUDISC_PROBE;
 282}
 283
 284static inline bool ip_sk_local_df(const struct sock *sk)
 285{
 286        return inet_sk(sk)->pmtudisc < IP_PMTUDISC_DO ||
 287               inet_sk(sk)->pmtudisc == IP_PMTUDISC_OMIT;
 288}
 289
 290static inline unsigned int ip_dst_mtu_maybe_forward(const struct dst_entry *dst,
 291                                                    bool forwarding)
 292{
 293        struct net *net = dev_net(dst->dev);
 294
 295        if (net->ipv4.sysctl_ip_fwd_use_pmtu ||
 296            dst_metric_locked(dst, RTAX_MTU) ||
 297            !forwarding)
 298                return dst_mtu(dst);
 299
 300        return min(dst->dev->mtu, IP_MAX_MTU);
 301}
 302
 303static inline unsigned int ip_skb_dst_mtu(const struct sk_buff *skb)
 304{
 305        if (!skb->sk || ip_sk_use_pmtu(skb->sk)) {
 306                bool forwarding = IPCB(skb)->flags & IPSKB_FORWARDED;
 307                return ip_dst_mtu_maybe_forward(skb_dst(skb), forwarding);
 308        } else {
 309                return min(skb_dst(skb)->dev->mtu, IP_MAX_MTU);
 310        }
 311}
 312
 313void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more);
 314
 315static inline void ip_select_ident(struct sk_buff *skb, struct dst_entry *dst, struct sock *sk)
 316{
 317        struct iphdr *iph = ip_hdr(skb);
 318
 319        if ((iph->frag_off & htons(IP_DF)) && !skb->local_df) {
 320                /* This is only to work around buggy Windows95/2000
 321                 * VJ compression implementations.  If the ID field
 322                 * does not change, they drop every other packet in
 323                 * a TCP stream using header compression.
 324                 */
 325                iph->id = (sk && inet_sk(sk)->inet_daddr) ?
 326                                        htons(inet_sk(sk)->inet_id++) : 0;
 327        } else
 328                __ip_select_ident(iph, dst, 0);
 329}
 330
 331static inline void ip_select_ident_more(struct sk_buff *skb, struct dst_entry *dst, struct sock *sk, int more)
 332{
 333        struct iphdr *iph = ip_hdr(skb);
 334
 335        if ((iph->frag_off & htons(IP_DF)) && !skb->local_df) {
 336                if (sk && inet_sk(sk)->inet_daddr) {
 337                        iph->id = htons(inet_sk(sk)->inet_id);
 338                        inet_sk(sk)->inet_id += 1 + more;
 339                } else
 340                        iph->id = 0;
 341        } else
 342                __ip_select_ident(iph, dst, more);
 343}
 344
 345/*
 346 *      Map a multicast IP onto multicast MAC for type ethernet.
 347 */
 348
 349static inline void ip_eth_mc_map(__be32 naddr, char *buf)
 350{
 351        __u32 addr=ntohl(naddr);
 352        buf[0]=0x01;
 353        buf[1]=0x00;
 354        buf[2]=0x5e;
 355        buf[5]=addr&0xFF;
 356        addr>>=8;
 357        buf[4]=addr&0xFF;
 358        addr>>=8;
 359        buf[3]=addr&0x7F;
 360}
 361
 362/*
 363 *      Map a multicast IP onto multicast MAC for type IP-over-InfiniBand.
 364 *      Leave P_Key as 0 to be filled in by driver.
 365 */
 366
 367static inline void ip_ib_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
 368{
 369        __u32 addr;
 370        unsigned char scope = broadcast[5] & 0xF;
 371
 372        buf[0]  = 0;            /* Reserved */
 373        buf[1]  = 0xff;         /* Multicast QPN */
 374        buf[2]  = 0xff;
 375        buf[3]  = 0xff;
 376        addr    = ntohl(naddr);
 377        buf[4]  = 0xff;
 378        buf[5]  = 0x10 | scope; /* scope from broadcast address */
 379        buf[6]  = 0x40;         /* IPv4 signature */
 380        buf[7]  = 0x1b;
 381        buf[8]  = broadcast[8];         /* P_Key */
 382        buf[9]  = broadcast[9];
 383        buf[10] = 0;
 384        buf[11] = 0;
 385        buf[12] = 0;
 386        buf[13] = 0;
 387        buf[14] = 0;
 388        buf[15] = 0;
 389        buf[19] = addr & 0xff;
 390        addr  >>= 8;
 391        buf[18] = addr & 0xff;
 392        addr  >>= 8;
 393        buf[17] = addr & 0xff;
 394        addr  >>= 8;
 395        buf[16] = addr & 0x0f;
 396}
 397
 398static inline void ip_ipgre_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
 399{
 400        if ((broadcast[0] | broadcast[1] | broadcast[2] | broadcast[3]) != 0)
 401                memcpy(buf, broadcast, 4);
 402        else
 403                memcpy(buf, &naddr, sizeof(naddr));
 404}
 405
 406#if IS_ENABLED(CONFIG_IPV6)
 407#include <linux/ipv6.h>
 408#endif
 409
 410static __inline__ void inet_reset_saddr(struct sock *sk)
 411{
 412        inet_sk(sk)->inet_rcv_saddr = inet_sk(sk)->inet_saddr = 0;
 413#if IS_ENABLED(CONFIG_IPV6)
 414        if (sk->sk_family == PF_INET6) {
 415                struct ipv6_pinfo *np = inet6_sk(sk);
 416
 417                memset(&np->saddr, 0, sizeof(np->saddr));
 418                memset(&sk->sk_v6_rcv_saddr, 0, sizeof(sk->sk_v6_rcv_saddr));
 419        }
 420#endif
 421}
 422
 423#endif
 424
 425static inline int sk_mc_loop(struct sock *sk)
 426{
 427        if (!sk)
 428                return 1;
 429        switch (sk->sk_family) {
 430        case AF_INET:
 431                return inet_sk(sk)->mc_loop;
 432#if IS_ENABLED(CONFIG_IPV6)
 433        case AF_INET6:
 434                return inet6_sk(sk)->mc_loop;
 435#endif
 436        }
 437        WARN_ON(1);
 438        return 1;
 439}
 440
 441bool ip_call_ra_chain(struct sk_buff *skb);
 442
 443/*
 444 *      Functions provided by ip_fragment.c
 445 */
 446
 447enum ip_defrag_users {
 448        IP_DEFRAG_LOCAL_DELIVER,
 449        IP_DEFRAG_CALL_RA_CHAIN,
 450        IP_DEFRAG_CONNTRACK_IN,
 451        __IP_DEFRAG_CONNTRACK_IN_END    = IP_DEFRAG_CONNTRACK_IN + USHRT_MAX,
 452        IP_DEFRAG_CONNTRACK_OUT,
 453        __IP_DEFRAG_CONNTRACK_OUT_END   = IP_DEFRAG_CONNTRACK_OUT + USHRT_MAX,
 454        IP_DEFRAG_CONNTRACK_BRIDGE_IN,
 455        __IP_DEFRAG_CONNTRACK_BRIDGE_IN = IP_DEFRAG_CONNTRACK_BRIDGE_IN + USHRT_MAX,
 456        IP_DEFRAG_VS_IN,
 457        IP_DEFRAG_VS_OUT,
 458        IP_DEFRAG_VS_FWD,
 459        IP_DEFRAG_AF_PACKET,
 460        IP_DEFRAG_MACVLAN,
 461};
 462
 463int ip_defrag(struct sk_buff *skb, u32 user);
 464#ifdef CONFIG_INET
 465struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user);
 466#else
 467static inline struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user)
 468{
 469        return skb;
 470}
 471#endif
 472int ip_frag_mem(struct net *net);
 473int ip_frag_nqueues(struct net *net);
 474
 475/*
 476 *      Functions provided by ip_forward.c
 477 */
 478 
 479int ip_forward(struct sk_buff *skb);
 480 
 481/*
 482 *      Functions provided by ip_options.c
 483 */
 484 
 485void ip_options_build(struct sk_buff *skb, struct ip_options *opt,
 486                      __be32 daddr, struct rtable *rt, int is_frag);
 487int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb);
 488void ip_options_fragment(struct sk_buff *skb);
 489int ip_options_compile(struct net *net, struct ip_options *opt,
 490                       struct sk_buff *skb);
 491int ip_options_get(struct net *net, struct ip_options_rcu **optp,
 492                   unsigned char *data, int optlen);
 493int ip_options_get_from_user(struct net *net, struct ip_options_rcu **optp,
 494                             unsigned char __user *data, int optlen);
 495void ip_options_undo(struct ip_options *opt);
 496void ip_forward_options(struct sk_buff *skb);
 497int ip_options_rcv_srr(struct sk_buff *skb);
 498
 499/*
 500 *      Functions provided by ip_sockglue.c
 501 */
 502
 503void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb);
 504void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb);
 505int ip_cmsg_send(struct net *net, struct msghdr *msg,
 506                 struct ipcm_cookie *ipc, bool allow_ipv6);
 507int ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
 508                  unsigned int optlen);
 509int ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
 510                  int __user *optlen);
 511int compat_ip_setsockopt(struct sock *sk, int level, int optname,
 512                         char __user *optval, unsigned int optlen);
 513int compat_ip_getsockopt(struct sock *sk, int level, int optname,
 514                         char __user *optval, int __user *optlen);
 515int ip_ra_control(struct sock *sk, unsigned char on,
 516                  void (*destructor)(struct sock *));
 517
 518int ip_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len);
 519void ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err, __be16 port,
 520                   u32 info, u8 *payload);
 521void ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 dport,
 522                    u32 info);
 523
 524#ifdef CONFIG_PROC_FS
 525int ip_misc_proc_init(void);
 526#endif
 527
 528#endif  /* _IP_H */
 529