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/snmp.h>
  32#include <net/flow.h>
  33
  34struct sock;
  35
  36struct inet_skb_parm {
  37        struct ip_options       opt;            /* Compiled IP options          */
  38        unsigned char           flags;
  39
  40#define IPSKB_FORWARDED         1
  41#define IPSKB_XFRM_TUNNEL_SIZE  2
  42#define IPSKB_XFRM_TRANSFORMED  4
  43#define IPSKB_FRAG_COMPLETE     8
  44#define IPSKB_REROUTED          16
  45};
  46
  47static inline unsigned int ip_hdrlen(const struct sk_buff *skb)
  48{
  49        return ip_hdr(skb)->ihl * 4;
  50}
  51
  52struct ipcm_cookie {
  53        __be32                  addr;
  54        int                     oif;
  55        struct ip_options_rcu   *opt;
  56        __u8                    tx_flags;
  57};
  58
  59#define IPCB(skb) ((struct inet_skb_parm*)((skb)->cb))
  60
  61struct ip_ra_chain {
  62        struct ip_ra_chain __rcu *next;
  63        struct sock             *sk;
  64        union {
  65                void                    (*destructor)(struct sock *);
  66                struct sock             *saved_sk;
  67        };
  68        struct rcu_head         rcu;
  69};
  70
  71extern struct ip_ra_chain __rcu *ip_ra_chain;
  72
  73/* IP flags. */
  74#define IP_CE           0x8000          /* Flag: "Congestion"           */
  75#define IP_DF           0x4000          /* Flag: "Don't Fragment"       */
  76#define IP_MF           0x2000          /* Flag: "More Fragments"       */
  77#define IP_OFFSET       0x1FFF          /* "Fragment Offset" part       */
  78
  79#define IP_FRAG_TIME    (30 * HZ)               /* fragment lifetime    */
  80
  81struct msghdr;
  82struct net_device;
  83struct packet_type;
  84struct rtable;
  85struct sockaddr;
  86
  87extern int              igmp_mc_proc_init(void);
  88
  89/*
  90 *      Functions provided by ip.c
  91 */
  92
  93extern int              ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk,
  94                                              __be32 saddr, __be32 daddr,
  95                                              struct ip_options_rcu *opt);
  96extern int              ip_rcv(struct sk_buff *skb, struct net_device *dev,
  97                               struct packet_type *pt, struct net_device *orig_dev);
  98extern int              ip_local_deliver(struct sk_buff *skb);
  99extern int              ip_mr_input(struct sk_buff *skb);
 100extern int              ip_output(struct sk_buff *skb);
 101extern int              ip_mc_output(struct sk_buff *skb);
 102extern int              ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *));
 103extern int              ip_do_nat(struct sk_buff *skb);
 104extern void             ip_send_check(struct iphdr *ip);
 105extern int              __ip_local_out(struct sk_buff *skb);
 106extern int              ip_local_out(struct sk_buff *skb);
 107extern int              ip_queue_xmit(struct sk_buff *skb, struct flowi *fl);
 108extern void             ip_init(void);
 109extern int              ip_append_data(struct sock *sk, struct flowi4 *fl4,
 110                                       int getfrag(void *from, char *to, int offset, int len,
 111                                                   int odd, struct sk_buff *skb),
 112                                void *from, int len, int protolen,
 113                                struct ipcm_cookie *ipc,
 114                                struct rtable **rt,
 115                                unsigned int flags);
 116extern int              ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb);
 117extern ssize_t          ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,
 118                                int offset, size_t size, int flags);
 119extern struct sk_buff  *__ip_make_skb(struct sock *sk,
 120                                      struct flowi4 *fl4,
 121                                      struct sk_buff_head *queue,
 122                                      struct inet_cork *cork);
 123extern int              ip_send_skb(struct net *net, struct sk_buff *skb);
 124extern int              ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4);
 125extern void             ip_flush_pending_frames(struct sock *sk);
 126extern struct sk_buff  *ip_make_skb(struct sock *sk,
 127                                    struct flowi4 *fl4,
 128                                    int getfrag(void *from, char *to, int offset, int len,
 129                                                int odd, struct sk_buff *skb),
 130                                    void *from, int length, int transhdrlen,
 131                                    struct ipcm_cookie *ipc,
 132                                    struct rtable **rtp,
 133                                    unsigned int flags);
 134
 135static inline struct sk_buff *ip_finish_skb(struct sock *sk, struct flowi4 *fl4)
 136{
 137        return __ip_make_skb(sk, fl4, &sk->sk_write_queue, &inet_sk(sk)->cork.base);
 138}
 139
 140/* datagram.c */
 141extern int              ip4_datagram_connect(struct sock *sk, 
 142                                             struct sockaddr *uaddr, int addr_len);
 143
 144struct ip_reply_arg {
 145        struct kvec iov[1];   
 146        int         flags;
 147        __wsum      csum;
 148        int         csumoffset; /* u16 offset of csum in iov[0].iov_base */
 149                                /* -1 if not needed */ 
 150        int         bound_dev_if;
 151        u8          tos;
 152}; 
 153
 154#define IP_REPLY_ARG_NOSRCCHECK 1
 155
 156static inline __u8 ip_reply_arg_flowi_flags(const struct ip_reply_arg *arg)
 157{
 158        return (arg->flags & IP_REPLY_ARG_NOSRCCHECK) ? FLOWI_FLAG_ANYSRC : 0;
 159}
 160
 161void ip_send_unicast_reply(struct net *net, struct sk_buff *skb, __be32 daddr,
 162                           __be32 saddr, const struct ip_reply_arg *arg,
 163                           unsigned int len);
 164
 165struct ipv4_config {
 166        int     log_martians;
 167        int     no_pmtu_disc;
 168};
 169
 170extern struct ipv4_config ipv4_config;
 171#define IP_INC_STATS(net, field)        SNMP_INC_STATS64((net)->mib.ip_statistics, field)
 172#define IP_INC_STATS_BH(net, field)     SNMP_INC_STATS64_BH((net)->mib.ip_statistics, field)
 173#define IP_ADD_STATS(net, field, val)   SNMP_ADD_STATS64((net)->mib.ip_statistics, field, val)
 174#define IP_ADD_STATS_BH(net, field, val) SNMP_ADD_STATS64_BH((net)->mib.ip_statistics, field, val)
 175#define IP_UPD_PO_STATS(net, field, val) SNMP_UPD_PO_STATS64((net)->mib.ip_statistics, field, val)
 176#define IP_UPD_PO_STATS_BH(net, field, val) SNMP_UPD_PO_STATS64_BH((net)->mib.ip_statistics, field, val)
 177#define NET_INC_STATS(net, field)       SNMP_INC_STATS((net)->mib.net_statistics, field)
 178#define NET_INC_STATS_BH(net, field)    SNMP_INC_STATS_BH((net)->mib.net_statistics, field)
 179#define NET_INC_STATS_USER(net, field)  SNMP_INC_STATS_USER((net)->mib.net_statistics, field)
 180#define NET_ADD_STATS_BH(net, field, adnd) SNMP_ADD_STATS_BH((net)->mib.net_statistics, field, adnd)
 181#define NET_ADD_STATS_USER(net, field, adnd) SNMP_ADD_STATS_USER((net)->mib.net_statistics, field, adnd)
 182
 183extern unsigned long snmp_fold_field(void __percpu *mib[], int offt);
 184#if BITS_PER_LONG==32
 185extern u64 snmp_fold_field64(void __percpu *mib[], int offt, size_t sync_off);
 186#else
 187static inline u64 snmp_fold_field64(void __percpu *mib[], int offt, size_t syncp_off)
 188{
 189        return snmp_fold_field(mib, offt);
 190}
 191#endif
 192extern int snmp_mib_init(void __percpu *ptr[2], size_t mibsize, size_t align);
 193extern void snmp_mib_free(void __percpu *ptr[2]);
 194
 195extern struct local_ports {
 196        seqlock_t       lock;
 197        int             range[2];
 198} sysctl_local_ports;
 199extern void inet_get_local_port_range(int *low, int *high);
 200
 201extern unsigned long *sysctl_local_reserved_ports;
 202static inline int inet_is_reserved_local_port(int port)
 203{
 204        return test_bit(port, sysctl_local_reserved_ports);
 205}
 206
 207extern int sysctl_ip_nonlocal_bind;
 208
 209/* From inetpeer.c */
 210extern int inet_peer_threshold;
 211extern int inet_peer_minttl;
 212extern int inet_peer_maxttl;
 213
 214/* From ip_input.c */
 215extern int sysctl_ip_early_demux;
 216
 217/* From ip_output.c */
 218extern int sysctl_ip_dynaddr;
 219
 220extern void ipfrag_init(void);
 221
 222extern void ip_static_sysctl_init(void);
 223
 224static inline bool ip_is_fragment(const struct iphdr *iph)
 225{
 226        return (iph->frag_off & htons(IP_MF | IP_OFFSET)) != 0;
 227}
 228
 229#ifdef CONFIG_INET
 230#include <net/dst.h>
 231
 232/* The function in 2.2 was invalid, producing wrong result for
 233 * check=0xFEFF. It was noticed by Arthur Skawina _year_ ago. --ANK(000625) */
 234static inline
 235int ip_decrease_ttl(struct iphdr *iph)
 236{
 237        u32 check = (__force u32)iph->check;
 238        check += (__force u32)htons(0x0100);
 239        iph->check = (__force __sum16)(check + (check>=0xFFFF));
 240        return --iph->ttl;
 241}
 242
 243static inline
 244int ip_dont_fragment(struct sock *sk, struct dst_entry *dst)
 245{
 246        return  inet_sk(sk)->pmtudisc == IP_PMTUDISC_DO ||
 247                (inet_sk(sk)->pmtudisc == IP_PMTUDISC_WANT &&
 248                 !(dst_metric_locked(dst, RTAX_MTU)));
 249}
 250
 251extern void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more);
 252
 253static inline void ip_select_ident(struct iphdr *iph, struct dst_entry *dst, struct sock *sk)
 254{
 255        if (iph->frag_off & htons(IP_DF)) {
 256                /* This is only to work around buggy Windows95/2000
 257                 * VJ compression implementations.  If the ID field
 258                 * does not change, they drop every other packet in
 259                 * a TCP stream using header compression.
 260                 */
 261                iph->id = (sk && inet_sk(sk)->inet_daddr) ?
 262                                        htons(inet_sk(sk)->inet_id++) : 0;
 263        } else
 264                __ip_select_ident(iph, dst, 0);
 265}
 266
 267static inline void ip_select_ident_more(struct iphdr *iph, struct dst_entry *dst, struct sock *sk, int more)
 268{
 269        if (iph->frag_off & htons(IP_DF)) {
 270                if (sk && inet_sk(sk)->inet_daddr) {
 271                        iph->id = htons(inet_sk(sk)->inet_id);
 272                        inet_sk(sk)->inet_id += 1 + more;
 273                } else
 274                        iph->id = 0;
 275        } else
 276                __ip_select_ident(iph, dst, more);
 277}
 278
 279/*
 280 *      Map a multicast IP onto multicast MAC for type ethernet.
 281 */
 282
 283static inline void ip_eth_mc_map(__be32 naddr, char *buf)
 284{
 285        __u32 addr=ntohl(naddr);
 286        buf[0]=0x01;
 287        buf[1]=0x00;
 288        buf[2]=0x5e;
 289        buf[5]=addr&0xFF;
 290        addr>>=8;
 291        buf[4]=addr&0xFF;
 292        addr>>=8;
 293        buf[3]=addr&0x7F;
 294}
 295
 296/*
 297 *      Map a multicast IP onto multicast MAC for type IP-over-InfiniBand.
 298 *      Leave P_Key as 0 to be filled in by driver.
 299 */
 300
 301static inline void ip_ib_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
 302{
 303        __u32 addr;
 304        unsigned char scope = broadcast[5] & 0xF;
 305
 306        buf[0]  = 0;            /* Reserved */
 307        buf[1]  = 0xff;         /* Multicast QPN */
 308        buf[2]  = 0xff;
 309        buf[3]  = 0xff;
 310        addr    = ntohl(naddr);
 311        buf[4]  = 0xff;
 312        buf[5]  = 0x10 | scope; /* scope from broadcast address */
 313        buf[6]  = 0x40;         /* IPv4 signature */
 314        buf[7]  = 0x1b;
 315        buf[8]  = broadcast[8];         /* P_Key */
 316        buf[9]  = broadcast[9];
 317        buf[10] = 0;
 318        buf[11] = 0;
 319        buf[12] = 0;
 320        buf[13] = 0;
 321        buf[14] = 0;
 322        buf[15] = 0;
 323        buf[19] = addr & 0xff;
 324        addr  >>= 8;
 325        buf[18] = addr & 0xff;
 326        addr  >>= 8;
 327        buf[17] = addr & 0xff;
 328        addr  >>= 8;
 329        buf[16] = addr & 0x0f;
 330}
 331
 332static inline void ip_ipgre_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
 333{
 334        if ((broadcast[0] | broadcast[1] | broadcast[2] | broadcast[3]) != 0)
 335                memcpy(buf, broadcast, 4);
 336        else
 337                memcpy(buf, &naddr, sizeof(naddr));
 338}
 339
 340#if IS_ENABLED(CONFIG_IPV6)
 341#include <linux/ipv6.h>
 342#endif
 343
 344static __inline__ void inet_reset_saddr(struct sock *sk)
 345{
 346        inet_sk(sk)->inet_rcv_saddr = inet_sk(sk)->inet_saddr = 0;
 347#if IS_ENABLED(CONFIG_IPV6)
 348        if (sk->sk_family == PF_INET6) {
 349                struct ipv6_pinfo *np = inet6_sk(sk);
 350
 351                memset(&np->saddr, 0, sizeof(np->saddr));
 352                memset(&np->rcv_saddr, 0, sizeof(np->rcv_saddr));
 353        }
 354#endif
 355}
 356
 357#endif
 358
 359static inline int sk_mc_loop(struct sock *sk)
 360{
 361        if (!sk)
 362                return 1;
 363        switch (sk->sk_family) {
 364        case AF_INET:
 365                return inet_sk(sk)->mc_loop;
 366#if IS_ENABLED(CONFIG_IPV6)
 367        case AF_INET6:
 368                return inet6_sk(sk)->mc_loop;
 369#endif
 370        }
 371        WARN_ON(1);
 372        return 1;
 373}
 374
 375extern bool ip_call_ra_chain(struct sk_buff *skb);
 376
 377/*
 378 *      Functions provided by ip_fragment.c
 379 */
 380
 381enum ip_defrag_users {
 382        IP_DEFRAG_LOCAL_DELIVER,
 383        IP_DEFRAG_CALL_RA_CHAIN,
 384        IP_DEFRAG_CONNTRACK_IN,
 385        __IP_DEFRAG_CONNTRACK_IN_END    = IP_DEFRAG_CONNTRACK_IN + USHRT_MAX,
 386        IP_DEFRAG_CONNTRACK_OUT,
 387        __IP_DEFRAG_CONNTRACK_OUT_END   = IP_DEFRAG_CONNTRACK_OUT + USHRT_MAX,
 388        IP_DEFRAG_CONNTRACK_BRIDGE_IN,
 389        __IP_DEFRAG_CONNTRACK_BRIDGE_IN = IP_DEFRAG_CONNTRACK_BRIDGE_IN + USHRT_MAX,
 390        IP_DEFRAG_VS_IN,
 391        IP_DEFRAG_VS_OUT,
 392        IP_DEFRAG_VS_FWD,
 393        IP_DEFRAG_AF_PACKET,
 394        IP_DEFRAG_MACVLAN,
 395};
 396
 397int ip_defrag(struct sk_buff *skb, u32 user);
 398#ifdef CONFIG_INET
 399struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user);
 400#else
 401static inline struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user)
 402{
 403        return skb;
 404}
 405#endif
 406int ip_frag_mem(struct net *net);
 407int ip_frag_nqueues(struct net *net);
 408
 409/*
 410 *      Functions provided by ip_forward.c
 411 */
 412 
 413extern int ip_forward(struct sk_buff *skb);
 414 
 415/*
 416 *      Functions provided by ip_options.c
 417 */
 418 
 419extern void ip_options_build(struct sk_buff *skb, struct ip_options *opt,
 420                             __be32 daddr, struct rtable *rt, int is_frag);
 421extern int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb);
 422extern void ip_options_fragment(struct sk_buff *skb);
 423extern int ip_options_compile(struct net *net,
 424                              struct ip_options *opt, struct sk_buff *skb);
 425extern int ip_options_get(struct net *net, struct ip_options_rcu **optp,
 426                          unsigned char *data, int optlen);
 427extern int ip_options_get_from_user(struct net *net, struct ip_options_rcu **optp,
 428                                    unsigned char __user *data, int optlen);
 429extern void ip_options_undo(struct ip_options * opt);
 430extern void ip_forward_options(struct sk_buff *skb);
 431extern int ip_options_rcv_srr(struct sk_buff *skb);
 432
 433/*
 434 *      Functions provided by ip_sockglue.c
 435 */
 436
 437extern void     ipv4_pktinfo_prepare(struct sk_buff *skb);
 438extern void     ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb);
 439extern int      ip_cmsg_send(struct net *net,
 440                             struct msghdr *msg, struct ipcm_cookie *ipc);
 441extern int      ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval, unsigned int optlen);
 442extern int      ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval, int __user *optlen);
 443extern int      compat_ip_setsockopt(struct sock *sk, int level,
 444                        int optname, char __user *optval, unsigned int optlen);
 445extern int      compat_ip_getsockopt(struct sock *sk, int level,
 446                        int optname, char __user *optval, int __user *optlen);
 447extern int      ip_ra_control(struct sock *sk, unsigned char on, void (*destructor)(struct sock *));
 448
 449extern int      ip_recv_error(struct sock *sk, struct msghdr *msg, int len);
 450extern void     ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err, 
 451                              __be16 port, u32 info, u8 *payload);
 452extern void     ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 dport,
 453                               u32 info);
 454
 455#ifdef CONFIG_PROC_FS
 456extern int ip_misc_proc_init(void);
 457#endif
 458
 459#endif  /* _IP_H */
 460
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