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
  33struct sock;
  34
  35struct inet_skb_parm
  36{
  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{
  54        __be32                  addr;
  55        int                     oif;
  56        struct ip_options       *opt;
  57};
  58
  59#define IPCB(skb) ((struct inet_skb_parm*)((skb)->cb))
  60
  61struct ip_ra_chain
  62{
  63        struct ip_ra_chain      *next;
  64        struct sock             *sk;
  65        void                    (*destructor)(struct sock *);
  66};
  67
  68extern struct ip_ra_chain *ip_ra_chain;
  69extern rwlock_t ip_ra_lock;
  70
  71/* IP flags. */
  72#define IP_CE           0x8000          /* Flag: "Congestion"           */
  73#define IP_DF           0x4000          /* Flag: "Don't Fragment"       */
  74#define IP_MF           0x2000          /* Flag: "More Fragments"       */
  75#define IP_OFFSET       0x1FFF          /* "Fragment Offset" part       */
  76
  77#define IP_FRAG_TIME    (30 * HZ)               /* fragment lifetime    */
  78
  79struct msghdr;
  80struct net_device;
  81struct packet_type;
  82struct rtable;
  83struct sockaddr;
  84
  85extern int              igmp_mc_proc_init(void);
  86
  87/*
  88 *      Functions provided by ip.c
  89 */
  90
  91extern int              ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk,
  92                                              __be32 saddr, __be32 daddr,
  93                                              struct ip_options *opt);
  94extern int              ip_rcv(struct sk_buff *skb, struct net_device *dev,
  95                               struct packet_type *pt, struct net_device *orig_dev);
  96extern int              ip_local_deliver(struct sk_buff *skb);
  97extern int              ip_mr_input(struct sk_buff *skb);
  98extern int              ip_output(struct sk_buff *skb);
  99extern int              ip_mc_output(struct sk_buff *skb);
 100extern int              ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *));
 101extern int              ip_do_nat(struct sk_buff *skb);
 102extern void             ip_send_check(struct iphdr *ip);
 103extern int              __ip_local_out(struct sk_buff *skb);
 104extern int              ip_local_out(struct sk_buff *skb);
 105extern int              ip_queue_xmit(struct sk_buff *skb, int ipfragok);
 106extern void             ip_init(void);
 107extern int              ip_append_data(struct sock *sk,
 108                                       int getfrag(void *from, char *to, int offset, int len,
 109                                                   int odd, struct sk_buff *skb),
 110                                void *from, int len, int protolen,
 111                                struct ipcm_cookie *ipc,
 112                                struct rtable *rt,
 113                                unsigned int flags);
 114extern int              ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb);
 115extern ssize_t          ip_append_page(struct sock *sk, struct page *page,
 116                                int offset, size_t size, int flags);
 117extern int              ip_push_pending_frames(struct sock *sk);
 118extern void             ip_flush_pending_frames(struct sock *sk);
 119
 120/* datagram.c */
 121extern int              ip4_datagram_connect(struct sock *sk, 
 122                                             struct sockaddr *uaddr, int addr_len);
 123
 124/*
 125 *      Map a multicast IP onto multicast MAC for type Token Ring.
 126 *      This conforms to RFC1469 Option 2 Multicasting i.e.
 127 *      using a functional address to transmit / receive 
 128 *      multicast packets.
 129 */
 130
 131static inline void ip_tr_mc_map(__be32 addr, char *buf)
 132{
 133        buf[0]=0xC0;
 134        buf[1]=0x00;
 135        buf[2]=0x00;
 136        buf[3]=0x04;
 137        buf[4]=0x00;
 138        buf[5]=0x00;
 139}
 140
 141struct ip_reply_arg {
 142        struct kvec iov[1];   
 143        __wsum      csum;
 144        int         csumoffset; /* u16 offset of csum in iov[0].iov_base */
 145                                /* -1 if not needed */ 
 146        int         bound_dev_if;
 147}; 
 148
 149void ip_send_reply(struct sock *sk, struct sk_buff *skb, struct ip_reply_arg *arg,
 150                   unsigned int len); 
 151
 152struct ipv4_config
 153{
 154        int     log_martians;
 155        int     no_pmtu_disc;
 156};
 157
 158extern struct ipv4_config ipv4_config;
 159#define IP_INC_STATS(net, field)        SNMP_INC_STATS((net)->mib.ip_statistics, field)
 160#define IP_INC_STATS_BH(net, field)     SNMP_INC_STATS_BH((net)->mib.ip_statistics, field)
 161#define IP_ADD_STATS_BH(net, field, val) SNMP_ADD_STATS_BH((net)->mib.ip_statistics, field, val)
 162#define NET_INC_STATS(net, field)       SNMP_INC_STATS((net)->mib.net_statistics, field)
 163#define NET_INC_STATS_BH(net, field)    SNMP_INC_STATS_BH((net)->mib.net_statistics, field)
 164#define NET_INC_STATS_USER(net, field)  SNMP_INC_STATS_USER((net)->mib.net_statistics, field)
 165#define NET_ADD_STATS_BH(net, field, adnd) SNMP_ADD_STATS_BH((net)->mib.net_statistics, field, adnd)
 166#define NET_ADD_STATS_USER(net, field, adnd) SNMP_ADD_STATS_USER((net)->mib.net_statistics, field, adnd)
 167
 168extern unsigned long snmp_fold_field(void *mib[], int offt);
 169extern int snmp_mib_init(void *ptr[2], size_t mibsize);
 170extern void snmp_mib_free(void *ptr[2]);
 171
 172extern void inet_get_local_port_range(int *low, int *high);
 173
 174extern int sysctl_ip_default_ttl;
 175extern int sysctl_ip_nonlocal_bind;
 176
 177extern struct ctl_path net_ipv4_ctl_path[];
 178
 179/* From inetpeer.c */
 180extern int inet_peer_threshold;
 181extern int inet_peer_minttl;
 182extern int inet_peer_maxttl;
 183extern int inet_peer_gc_mintime;
 184extern int inet_peer_gc_maxtime;
 185
 186/* From ip_output.c */
 187extern int sysctl_ip_dynaddr;
 188
 189extern void ipfrag_init(void);
 190
 191extern void ip_static_sysctl_init(void);
 192
 193#ifdef CONFIG_INET
 194#include <net/dst.h>
 195
 196/* The function in 2.2 was invalid, producing wrong result for
 197 * check=0xFEFF. It was noticed by Arthur Skawina _year_ ago. --ANK(000625) */
 198static inline
 199int ip_decrease_ttl(struct iphdr *iph)
 200{
 201        u32 check = (__force u32)iph->check;
 202        check += (__force u32)htons(0x0100);
 203        iph->check = (__force __sum16)(check + (check>=0xFFFF));
 204        return --iph->ttl;
 205}
 206
 207static inline
 208int ip_dont_fragment(struct sock *sk, struct dst_entry *dst)
 209{
 210        return (inet_sk(sk)->pmtudisc == IP_PMTUDISC_DO ||
 211                (inet_sk(sk)->pmtudisc == IP_PMTUDISC_WANT &&
 212                 !(dst_metric_locked(dst, RTAX_MTU))));
 213}
 214
 215extern void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more);
 216
 217static inline void ip_select_ident(struct iphdr *iph, struct dst_entry *dst, struct sock *sk)
 218{
 219        if (iph->frag_off & htons(IP_DF)) {
 220                /* This is only to work around buggy Windows95/2000
 221                 * VJ compression implementations.  If the ID field
 222                 * does not change, they drop every other packet in
 223                 * a TCP stream using header compression.
 224                 */
 225                iph->id = (sk && inet_sk(sk)->daddr) ?
 226                                        htons(inet_sk(sk)->id++) : 0;
 227        } else
 228                __ip_select_ident(iph, dst, 0);
 229}
 230
 231static inline void ip_select_ident_more(struct iphdr *iph, struct dst_entry *dst, struct sock *sk, int more)
 232{
 233        if (iph->frag_off & htons(IP_DF)) {
 234                if (sk && inet_sk(sk)->daddr) {
 235                        iph->id = htons(inet_sk(sk)->id);
 236                        inet_sk(sk)->id += 1 + more;
 237                } else
 238                        iph->id = 0;
 239        } else
 240                __ip_select_ident(iph, dst, more);
 241}
 242
 243/*
 244 *      Map a multicast IP onto multicast MAC for type ethernet.
 245 */
 246
 247static inline void ip_eth_mc_map(__be32 naddr, char *buf)
 248{
 249        __u32 addr=ntohl(naddr);
 250        buf[0]=0x01;
 251        buf[1]=0x00;
 252        buf[2]=0x5e;
 253        buf[5]=addr&0xFF;
 254        addr>>=8;
 255        buf[4]=addr&0xFF;
 256        addr>>=8;
 257        buf[3]=addr&0x7F;
 258}
 259
 260/*
 261 *      Map a multicast IP onto multicast MAC for type IP-over-InfiniBand.
 262 *      Leave P_Key as 0 to be filled in by driver.
 263 */
 264
 265static inline void ip_ib_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
 266{
 267        __u32 addr;
 268        unsigned char scope = broadcast[5] & 0xF;
 269
 270        buf[0]  = 0;            /* Reserved */
 271        buf[1]  = 0xff;         /* Multicast QPN */
 272        buf[2]  = 0xff;
 273        buf[3]  = 0xff;
 274        addr    = ntohl(naddr);
 275        buf[4]  = 0xff;
 276        buf[5]  = 0x10 | scope; /* scope from broadcast address */
 277        buf[6]  = 0x40;         /* IPv4 signature */
 278        buf[7]  = 0x1b;
 279        buf[8]  = broadcast[8];         /* P_Key */
 280        buf[9]  = broadcast[9];
 281        buf[10] = 0;
 282        buf[11] = 0;
 283        buf[12] = 0;
 284        buf[13] = 0;
 285        buf[14] = 0;
 286        buf[15] = 0;
 287        buf[19] = addr & 0xff;
 288        addr  >>= 8;
 289        buf[18] = addr & 0xff;
 290        addr  >>= 8;
 291        buf[17] = addr & 0xff;
 292        addr  >>= 8;
 293        buf[16] = addr & 0x0f;
 294}
 295
 296#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 297#include <linux/ipv6.h>
 298#endif
 299
 300static __inline__ void inet_reset_saddr(struct sock *sk)
 301{
 302        inet_sk(sk)->rcv_saddr = inet_sk(sk)->saddr = 0;
 303#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 304        if (sk->sk_family == PF_INET6) {
 305                struct ipv6_pinfo *np = inet6_sk(sk);
 306
 307                memset(&np->saddr, 0, sizeof(np->saddr));
 308                memset(&np->rcv_saddr, 0, sizeof(np->rcv_saddr));
 309        }
 310#endif
 311}
 312
 313#endif
 314
 315extern int      ip_call_ra_chain(struct sk_buff *skb);
 316
 317/*
 318 *      Functions provided by ip_fragment.c
 319 */
 320
 321enum ip_defrag_users
 322{
 323        IP_DEFRAG_LOCAL_DELIVER,
 324        IP_DEFRAG_CALL_RA_CHAIN,
 325        IP_DEFRAG_CONNTRACK_IN,
 326        IP_DEFRAG_CONNTRACK_OUT,
 327        IP_DEFRAG_VS_IN,
 328        IP_DEFRAG_VS_OUT,
 329        IP_DEFRAG_VS_FWD
 330};
 331
 332int ip_defrag(struct sk_buff *skb, u32 user);
 333int ip_frag_mem(struct net *net);
 334int ip_frag_nqueues(struct net *net);
 335
 336/*
 337 *      Functions provided by ip_forward.c
 338 */
 339 
 340extern int ip_forward(struct sk_buff *skb);
 341 
 342/*
 343 *      Functions provided by ip_options.c
 344 */
 345 
 346extern void ip_options_build(struct sk_buff *skb, struct ip_options *opt, __be32 daddr, struct rtable *rt, int is_frag);
 347extern int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb);
 348extern void ip_options_fragment(struct sk_buff *skb);
 349extern int ip_options_compile(struct net *net,
 350                              struct ip_options *opt, struct sk_buff *skb);
 351extern int ip_options_get(struct net *net, struct ip_options **optp,
 352                          unsigned char *data, int optlen);
 353extern int ip_options_get_from_user(struct net *net, struct ip_options **optp,
 354                                    unsigned char __user *data, int optlen);
 355extern void ip_options_undo(struct ip_options * opt);
 356extern void ip_forward_options(struct sk_buff *skb);
 357extern int ip_options_rcv_srr(struct sk_buff *skb);
 358
 359/*
 360 *      Functions provided by ip_sockglue.c
 361 */
 362
 363extern void     ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb);
 364extern int      ip_cmsg_send(struct net *net,
 365                             struct msghdr *msg, struct ipcm_cookie *ipc);
 366extern int      ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval, int optlen);
 367extern int      ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval, int __user *optlen);
 368extern int      compat_ip_setsockopt(struct sock *sk, int level,
 369                        int optname, char __user *optval, int optlen);
 370extern int      compat_ip_getsockopt(struct sock *sk, int level,
 371                        int optname, char __user *optval, int __user *optlen);
 372extern int      ip_ra_control(struct sock *sk, unsigned char on, void (*destructor)(struct sock *));
 373
 374extern int      ip_recv_error(struct sock *sk, struct msghdr *msg, int len);
 375extern void     ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err, 
 376                              __be16 port, u32 info, u8 *payload);
 377extern void     ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 dport,
 378                               u32 info);
 379
 380/* sysctl helpers - any sysctl which holds a value that ends up being
 381 * fed into the routing cache should use these handlers.
 382 */
 383int ipv4_doint_and_flush(ctl_table *ctl, int write,
 384                         struct file* filp, void __user *buffer,
 385                         size_t *lenp, loff_t *ppos);
 386int ipv4_doint_and_flush_strategy(ctl_table *table, int __user *name, int nlen,
 387                                  void __user *oldval, size_t __user *oldlenp,
 388                                  void __user *newval, size_t newlen);
 389#ifdef CONFIG_PROC_FS
 390extern int ip_misc_proc_init(void);
 391#endif
 392
 393#endif  /* _IP_H */
 394
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