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
  30 #include <net/inet_sock.h>
  31 #include <net/snmp.h>
  32
  33 struct sock;
  34
  35 struct 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
  47 static inline unsigned int ip_hdrlen(const struct sk_buff *skb)
  48 {
  49         return ip_hdr(skb)->ihl * 4;
  50 }
  51
  52 struct 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
  61 struct ip_ra_chain
  62 {
  63         struct ip_ra_chain      *next;
  64         struct sock             *sk;
  65         void                    (*destructor)(struct sock *);
  66 };
  67
  68 extern struct ip_ra_chain *ip_ra_chain;
  69 extern 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
  79 struct msghdr;
  80 struct net_device;
  81 struct packet_type;
  82 struct rtable;
  83 struct sockaddr;
  84
  85 extern int              igmp_mc_proc_init(void);
  86
  87 /*
  88  *      Functions provided by ip.c
  89  */
  90
  91 extern int              ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk,
  92                                               __be32 saddr, __be32 daddr,
  93                                               struct ip_options *opt);
  94 extern int              ip_rcv(struct sk_buff *skb, struct net_device *dev,
  95                                struct packet_type *pt, struct net_device *orig_dev);
  96 extern int              ip_local_deliver(struct sk_buff *skb);
  97 extern int              ip_mr_input(struct sk_buff *skb);
  98 extern int              ip_output(struct sk_buff *skb);
  99 extern int              ip_mc_output(struct sk_buff *skb);
 100 extern int              ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *));
 101 extern int              ip_do_nat(struct sk_buff *skb);
 102 extern void             ip_send_check(struct iphdr *ip);
 103 extern int              __ip_local_out(struct sk_buff *skb);
 104 extern int              ip_local_out(struct sk_buff *skb);
 105 extern int              ip_queue_xmit(struct sk_buff *skb, int ipfragok);
 106 extern void             ip_init(void);
 107 extern 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);
 114 extern int              ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb);
 115 extern ssize_t          ip_append_page(struct sock *sk, struct page *page,
 116                                 int offset, size_t size, int flags);
 117 extern int              ip_push_pending_frames(struct sock *sk);
 118 extern void             ip_flush_pending_frames(struct sock *sk);
 119
 120 /* datagram.c */
 121 extern 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
 131 static 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
 141 struct 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
 149 void ip_send_reply(struct sock *sk, struct sk_buff *skb, struct ip_reply_arg *arg,
 150                    unsigned int len);
 151
 152 struct ipv4_config
 153 {
 154         int     log_martians;
 155         int     no_pmtu_disc;
 156 };
 157
 158 extern struct ipv4_config ipv4_config;
 159 DECLARE_SNMP_STAT(struct ipstats_mib, ip_statistics);
 160 #define IP_INC_STATS(field)             SNMP_INC_STATS(ip_statistics, field)
 161 #define IP_INC_STATS_BH(field)          SNMP_INC_STATS_BH(ip_statistics, field)
 162 #define IP_INC_STATS_USER(field)        SNMP_INC_STATS_USER(ip_statistics, field)
 163 #define IP_ADD_STATS_BH(field, val)     SNMP_ADD_STATS_BH(ip_statistics, field, val)
 164 DECLARE_SNMP_STAT(struct linux_mib, net_statistics);
 165 #define NET_INC_STATS(field)            SNMP_INC_STATS(net_statistics, field)
 166 #define NET_INC_STATS_BH(field)         SNMP_INC_STATS_BH(net_statistics, field)
 167 #define NET_INC_STATS_USER(field)       SNMP_INC_STATS_USER(net_statistics, field)
 168 #define NET_ADD_STATS_BH(field, adnd)   SNMP_ADD_STATS_BH(net_statistics, field, adnd)
 169 #define NET_ADD_STATS_USER(field, adnd) SNMP_ADD_STATS_USER(net_statistics, field, adnd)
 170
 171 extern unsigned long snmp_fold_field(void *mib[], int offt);
 172 extern int snmp_mib_init(void *ptr[2], size_t mibsize);
 173 extern void snmp_mib_free(void *ptr[2]);
 174
 175 extern void inet_get_local_port_range(int *low, int *high);
 176
 177 extern int sysctl_ip_default_ttl;
 178 extern int sysctl_ip_nonlocal_bind;
 179
 180 extern struct ctl_path net_ipv4_ctl_path[];
 181
 182 /* From inetpeer.c */
 183 extern int inet_peer_threshold;
 184 extern int inet_peer_minttl;
 185 extern int inet_peer_maxttl;
 186 extern int inet_peer_gc_mintime;
 187 extern int inet_peer_gc_maxtime;
 188
 189 /* From ip_output.c */
 190 extern int sysctl_ip_dynaddr;
 191
 192 extern void ipfrag_init(void);
 193
 194 #ifdef CONFIG_INET
 195 #include <net/dst.h>
 196
 197 /* The function in 2.2 was invalid, producing wrong result for
 198  * check=0xFEFF. It was noticed by Arthur Skawina _year_ ago. --ANK(000625) */
 199 static inline
 200 int ip_decrease_ttl(struct iphdr *iph)
 201 {
 202         u32 check = (__force u32)iph->check;
 203         check += (__force u32)htons(0x0100);
 204         iph->check = (__force __sum16)(check + (check>=0xFFFF));
 205         return --iph->ttl;
 206 }
 207
 208 static inline
 209 int ip_dont_fragment(struct sock *sk, struct dst_entry *dst)
 210 {
 211         return (inet_sk(sk)->pmtudisc == IP_PMTUDISC_DO ||
 212                 (inet_sk(sk)->pmtudisc == IP_PMTUDISC_WANT &&
 213                  !(dst_metric(dst, RTAX_LOCK)&(1<<RTAX_MTU))));
 214 }
 215
 216 extern void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more);
 217
 218 static inline void ip_select_ident(struct iphdr *iph, struct dst_entry *dst, struct sock *sk)
 219 {
 220         if (iph->frag_off & htons(IP_DF)) {
 221                 /* This is only to work around buggy Windows95/2000
 222                  * VJ compression implementations.  If the ID field
 223                  * does not change, they drop every other packet in
 224                  * a TCP stream using header compression.
 225                  */
 226                 iph->id = (sk && inet_sk(sk)->daddr) ?
 227                                         htons(inet_sk(sk)->id++) : 0;
 228         } else
 229                 __ip_select_ident(iph, dst, 0);
 230 }
 231
 232 static inline void ip_select_ident_more(struct iphdr *iph, struct dst_entry *dst, struct sock *sk, int more)
 233 {
 234         if (iph->frag_off & htons(IP_DF)) {
 235                 if (sk && inet_sk(sk)->daddr) {
 236                         iph->id = htons(inet_sk(sk)->id);
 237                         inet_sk(sk)->id += 1 + more;
 238                 } else
 239                         iph->id = 0;
 240         } else
 241                 __ip_select_ident(iph, dst, more);
 242 }
 243
 244 /*
 245  *      Map a multicast IP onto multicast MAC for type ethernet.
 246  */
 247
 248 static inline void ip_eth_mc_map(__be32 naddr, char *buf)
 249 {
 250         __u32 addr=ntohl(naddr);
 251         buf[0]=0x01;
 252         buf[1]=0x00;
 253         buf[2]=0x5e;
 254         buf[5]=addr&0xFF;
 255         addr>>=8;
 256         buf[4]=addr&0xFF;
 257         addr>>=8;
 258         buf[3]=addr&0x7F;
 259 }
 260
 261 /*
 262  *      Map a multicast IP onto multicast MAC for type IP-over-InfiniBand.
 263  *      Leave P_Key as 0 to be filled in by driver.
 264  */
 265
 266 static inline void ip_ib_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
 267 {
 268         __u32 addr;
 269         unsigned char scope = broadcast[5] & 0xF;
 270
 271         buf[0]  = 0;            /* Reserved */
 272         buf[1]  = 0xff;         /* Multicast QPN */
 273         buf[2]  = 0xff;
 274         buf[3]  = 0xff;
 275         addr    = ntohl(naddr);
 276         buf[4]  = 0xff;
 277         buf[5]  = 0x10 | scope; /* scope from broadcast address */
 278         buf[6]  = 0x40;         /* IPv4 signature */
 279         buf[7]  = 0x1b;
 280         buf[8]  = broadcast[8];         /* P_Key */
 281         buf[9]  = broadcast[9];
 282         buf[10] = 0;
 283         buf[11] = 0;
 284         buf[12] = 0;
 285         buf[13] = 0;
 286         buf[14] = 0;
 287         buf[15] = 0;
 288         buf[19] = addr & 0xff;
 289         addr  >>= 8;
 290         buf[18] = addr & 0xff;
 291         addr  >>= 8;
 292         buf[17] = addr & 0xff;
 293         addr  >>= 8;
 294         buf[16] = addr & 0x0f;
 295 }
 296
 297 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 298 #include <linux/ipv6.h>
 299 #endif
 300
 301 static __inline__ void inet_reset_saddr(struct sock *sk)
 302 {
 303         inet_sk(sk)->rcv_saddr = inet_sk(sk)->saddr = 0;
 304 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 305         if (sk->sk_family == PF_INET6) {
 306                 struct ipv6_pinfo *np = inet6_sk(sk);
 307
 308                 memset(&np->saddr, 0, sizeof(np->saddr));
 309                 memset(&np->rcv_saddr, 0, sizeof(np->rcv_saddr));
 310         }
 311 #endif
 312 }
 313
 314 #endif
 315
 316 extern int      ip_call_ra_chain(struct sk_buff *skb);
 317
 318 /*
 319  *      Functions provided by ip_fragment.c
 320  */
 321
 322 enum ip_defrag_users
 323 {
 324         IP_DEFRAG_LOCAL_DELIVER,
 325         IP_DEFRAG_CALL_RA_CHAIN,
 326         IP_DEFRAG_CONNTRACK_IN,
 327         IP_DEFRAG_CONNTRACK_OUT,
 328         IP_DEFRAG_VS_IN,
 329         IP_DEFRAG_VS_OUT,
 330         IP_DEFRAG_VS_FWD
 331 };
 332
 333 int ip_defrag(struct sk_buff *skb, u32 user);
 334 int ip_frag_mem(void);
 335 int ip_frag_nqueues(struct net *net);
 336
 337 /*
 338  *      Functions provided by ip_forward.c
 339  */
 340
 341 extern int ip_forward(struct sk_buff *skb);
 342
 343 /*
 344  *      Functions provided by ip_options.c
 345  */
 346
 347 extern void ip_options_build(struct sk_buff *skb, struct ip_options *opt, __be32 daddr, struct rtable *rt, int is_frag);
 348 extern int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb);
 349 extern void ip_options_fragment(struct sk_buff *skb);
 350 extern int ip_options_compile(struct ip_options *opt, struct sk_buff *skb);
 351 extern int ip_options_get(struct ip_options **optp,
 352                           unsigned char *data, int optlen);
 353 extern int ip_options_get_from_user(struct ip_options **optp,
 354                                     unsigned char __user *data, int optlen);
 355 extern void ip_options_undo(struct ip_options * opt);
 356 extern void ip_forward_options(struct sk_buff *skb);
 357 extern int ip_options_rcv_srr(struct sk_buff *skb);
 358
 359 /*
 360  *      Functions provided by ip_sockglue.c
 361  */
 362
 363 extern void     ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb);
 364 extern int      ip_cmsg_send(struct msghdr *msg, struct ipcm_cookie *ipc);
 365 extern int      ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval, int optlen);
 366 extern int      ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval, int __user *optlen);
 367 extern int      compat_ip_setsockopt(struct sock *sk, int level,
 368                         int optname, char __user *optval, int optlen);
 369 extern int      compat_ip_getsockopt(struct sock *sk, int level,
 370                         int optname, char __user *optval, int __user *optlen);
 371 extern int      ip_ra_control(struct sock *sk, unsigned char on, void (*destructor)(struct sock *));
 372
 373 extern int      ip_recv_error(struct sock *sk, struct msghdr *msg, int len);
 374 extern void     ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err,
 375                               __be16 port, u32 info, u8 *payload);
 376 extern void     ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 dport,
 377                                u32 info);
 378
 379 /* sysctl helpers - any sysctl which holds a value that ends up being
 380  * fed into the routing cache should use these handlers.
 381  */
 382 int ipv4_doint_and_flush(ctl_table *ctl, int write,
 383                          struct file* filp, void __user *buffer,
 384                          size_t *lenp, loff_t *ppos);
 385 int ipv4_doint_and_flush_strategy(ctl_table *table, int __user *name, int nlen,
 386                                   void __user *oldval, size_t __user *oldlenp,
 387                                   void __user *newval, size_t newlen);
 388 #ifdef CONFIG_PROC_FS
 389 extern int ip_misc_proc_init(void);
 390 #endif
 391
 392 #endif  /* _IP_H */