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/config.h>
  26 #include <linux/types.h>
  27 #include <linux/socket.h>
  28 #include <linux/ip.h>
  29 #include <linux/in.h>
  30 #include <linux/netdevice.h>
  31 #include <linux/inetdevice.h>
  32 #include <linux/in_route.h>
  33 #include <net/route.h>
  34 #include <net/arp.h>
  35 #include <net/snmp.h>
  36
  37 struct sock;
  38
  39 struct inet_skb_parm
  40 {
  41         struct ip_options       opt;            /* Compiled IP options          */
  42         unsigned char           flags;
  43
  44 #define IPSKB_MASQUERADED       1
  45 #define IPSKB_TRANSLATED        2
  46 #define IPSKB_FORWARDED         4
  47 #define IPSKB_XFRM_TUNNEL_SIZE  8
  48 };
  49
  50 struct ipcm_cookie
  51 {
  52         u32                     addr;
  53         int                     oif;
  54         struct ip_options       *opt;
  55 };
  56
  57 #define IPCB(skb) ((struct inet_skb_parm*)((skb)->cb))
  58
  59 struct ip_ra_chain
  60 {
  61         struct ip_ra_chain      *next;
  62         struct sock             *sk;
  63         void                    (*destructor)(struct sock *);
  64 };
  65
  66 extern struct ip_ra_chain *ip_ra_chain;
  67 extern rwlock_t ip_ra_lock;
  68
  69 /* IP flags. */
  70 #define IP_CE           0x8000          /* Flag: "Congestion"           */
  71 #define IP_DF           0x4000          /* Flag: "Don't Fragment"       */
  72 #define IP_MF           0x2000          /* Flag: "More Fragments"       */
  73 #define IP_OFFSET       0x1FFF          /* "Fragment Offset" part       */
  74
  75 #define IP_FRAG_TIME    (30 * HZ)               /* fragment lifetime    */
  76
  77 extern void             ip_mc_dropsocket(struct sock *);
  78 extern void             ip_mc_dropdevice(struct net_device *dev);
  79 extern int              igmp_mc_proc_init(void);
  80
  81 /*
  82  *      Functions provided by ip.c
  83  */
  84
  85 extern int              ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk,
  86                                               u32 saddr, u32 daddr,
  87                                               struct ip_options *opt);
  88 extern int              ip_rcv(struct sk_buff *skb, struct net_device *dev,
  89                                struct packet_type *pt);
  90 extern int              ip_local_deliver(struct sk_buff *skb);
  91 extern int              ip_mr_input(struct sk_buff *skb);
  92 extern int              ip_output(struct sk_buff *skb);
  93 extern int              ip_mc_output(struct sk_buff *skb);
  94 extern int              ip_fragment(struct sk_buff *skb, int (*out)(struct sk_buff*));
  95 extern int              ip_do_nat(struct sk_buff *skb);
  96 extern void             ip_send_check(struct iphdr *ip);
  97 extern int              ip_queue_xmit(struct sk_buff *skb, int ipfragok);
  98 extern void             ip_init(void);
  99 extern int              ip_append_data(struct sock *sk,
 100                                        int getfrag(void *from, char *to, int offset, int len,
 101                                                    int odd, struct sk_buff *skb),
 102                                 void *from, int len, int protolen,
 103                                 struct ipcm_cookie *ipc,
 104                                 struct rtable *rt,
 105                                 unsigned int flags);
 106 extern int              ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb);
 107 extern ssize_t          ip_append_page(struct sock *sk, struct page *page,
 108                                 int offset, size_t size, int flags);
 109 extern int              ip_push_pending_frames(struct sock *sk);
 110 extern void             ip_flush_pending_frames(struct sock *sk);
 111
 112 /* datagram.c */
 113 extern int              ip4_datagram_connect(struct sock *sk,
 114                                              struct sockaddr *uaddr, int addr_len);
 115
 116 /*
 117  *      Map a multicast IP onto multicast MAC for type Token Ring.
 118  *      This conforms to RFC1469 Option 2 Multicasting i.e.
 119  *      using a functional address to transmit / receive
 120  *      multicast packets.
 121  */
 122
 123 static inline void ip_tr_mc_map(u32 addr, char *buf)
 124 {
 125         buf[0]=0xC0;
 126         buf[1]=0x00;
 127         buf[2]=0x00;
 128         buf[3]=0x04;
 129         buf[4]=0x00;
 130         buf[5]=0x00;
 131 }
 132
 133 struct ip_reply_arg {
 134         struct kvec iov[1];
 135         u32         csum;
 136         int         csumoffset; /* u16 offset of csum in iov[0].iov_base */
 137                                 /* -1 if not needed */
 138 };
 139
 140 void ip_send_reply(struct sock *sk, struct sk_buff *skb, struct ip_reply_arg *arg,
 141                    unsigned int len);
 142
 143 extern int ip_finish_output(struct sk_buff *skb);
 144
 145 struct ipv4_config
 146 {
 147         int     log_martians;
 148         int     autoconfig;
 149         int     no_pmtu_disc;
 150 };
 151
 152 extern struct ipv4_config ipv4_config;
 153 DECLARE_SNMP_STAT(struct ipstats_mib, ip_statistics);
 154 #define IP_INC_STATS(field)             SNMP_INC_STATS(ip_statistics, field)
 155 #define IP_INC_STATS_BH(field)          SNMP_INC_STATS_BH(ip_statistics, field)
 156 #define IP_INC_STATS_USER(field)        SNMP_INC_STATS_USER(ip_statistics, field)
 157 DECLARE_SNMP_STAT(struct linux_mib, net_statistics);
 158 #define NET_INC_STATS(field)            SNMP_INC_STATS(net_statistics, field)
 159 #define NET_INC_STATS_BH(field)         SNMP_INC_STATS_BH(net_statistics, field)
 160 #define NET_INC_STATS_USER(field)       SNMP_INC_STATS_USER(net_statistics, field)
 161 #define NET_ADD_STATS_BH(field, adnd)   SNMP_ADD_STATS_BH(net_statistics, field, adnd)
 162 #define NET_ADD_STATS_USER(field, adnd) SNMP_ADD_STATS_USER(net_statistics, field, adnd)
 163
 164 extern int sysctl_local_port_range[2];
 165 extern int sysctl_ip_default_ttl;
 166 extern int sysctl_ip_nonlocal_bind;
 167
 168 #ifdef CONFIG_INET
 169 /* The function in 2.2 was invalid, producing wrong result for
 170  * check=0xFEFF. It was noticed by Arthur Skawina _year_ ago. --ANK(000625) */
 171 static inline
 172 int ip_decrease_ttl(struct iphdr *iph)
 173 {
 174         u32 check = iph->check;
 175         check += htons(0x0100);
 176         iph->check = check + (check>=0xFFFF);
 177         return --iph->ttl;
 178 }
 179
 180 static inline
 181 int ip_dont_fragment(struct sock *sk, struct dst_entry *dst)
 182 {
 183         return (inet_sk(sk)->pmtudisc == IP_PMTUDISC_DO ||
 184                 (inet_sk(sk)->pmtudisc == IP_PMTUDISC_WANT &&
 185                  !(dst_metric(dst, RTAX_LOCK)&(1<<RTAX_MTU))));
 186 }
 187
 188 extern void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more);
 189
 190 static inline void ip_select_ident(struct iphdr *iph, struct dst_entry *dst, struct sock *sk)
 191 {
 192         if (iph->frag_off & htons(IP_DF)) {
 193                 /* This is only to work around buggy Windows95/2000
 194                  * VJ compression implementations.  If the ID field
 195                  * does not change, they drop every other packet in
 196                  * a TCP stream using header compression.
 197                  */
 198                 iph->id = (sk && inet_sk(sk)->daddr) ?
 199                                         htons(inet_sk(sk)->id++) : 0;
 200         } else
 201                 __ip_select_ident(iph, dst, 0);
 202 }
 203
 204 static inline void ip_select_ident_more(struct iphdr *iph, struct dst_entry *dst, struct sock *sk, int more)
 205 {
 206         if (iph->frag_off & htons(IP_DF)) {
 207                 if (sk && inet_sk(sk)->daddr) {
 208                         iph->id = htons(inet_sk(sk)->id);
 209                         inet_sk(sk)->id += 1 + more;
 210                 } else
 211                         iph->id = 0;
 212         } else
 213                 __ip_select_ident(iph, dst, more);
 214 }
 215
 216 /*
 217  *      Map a multicast IP onto multicast MAC for type ethernet.
 218  */
 219
 220 static inline void ip_eth_mc_map(u32 addr, char *buf)
 221 {
 222         addr=ntohl(addr);
 223         buf[0]=0x01;
 224         buf[1]=0x00;
 225         buf[2]=0x5e;
 226         buf[5]=addr&0xFF;
 227         addr>>=8;
 228         buf[4]=addr&0xFF;
 229         addr>>=8;
 230         buf[3]=addr&0x7F;
 231 }
 232
 233 /*
 234  *      Map a multicast IP onto multicast MAC for type IP-over-InfiniBand.
 235  *      Leave P_Key as 0 to be filled in by driver.
 236  */
 237
 238 static inline void ip_ib_mc_map(u32 addr, char *buf)
 239 {
 240         buf[0]  = 0;            /* Reserved */
 241         buf[1]  = 0xff;         /* Multicast QPN */
 242         buf[2]  = 0xff;
 243         buf[3]  = 0xff;
 244         addr    = ntohl(addr);
 245         buf[4]  = 0xff;
 246         buf[5]  = 0x12;         /* link local scope */
 247         buf[6]  = 0x40;         /* IPv4 signature */
 248         buf[7]  = 0x1b;
 249         buf[8]  = 0;            /* P_Key */
 250         buf[9]  = 0;
 251         buf[10] = 0;
 252         buf[11] = 0;
 253         buf[12] = 0;
 254         buf[13] = 0;
 255         buf[14] = 0;
 256         buf[15] = 0;
 257         buf[19] = addr & 0xff;
 258         addr  >>= 8;
 259         buf[18] = addr & 0xff;
 260         addr  >>= 8;
 261         buf[17] = addr & 0xff;
 262         addr  >>= 8;
 263         buf[16] = addr & 0x0f;
 264 }
 265
 266 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 267 #include <linux/ipv6.h>
 268 #endif
 269
 270 static __inline__ void inet_reset_saddr(struct sock *sk)
 271 {
 272         inet_sk(sk)->rcv_saddr = inet_sk(sk)->saddr = 0;
 273 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 274         if (sk->sk_family == PF_INET6) {
 275                 struct ipv6_pinfo *np = inet6_sk(sk);
 276
 277                 memset(&np->saddr, 0, sizeof(np->saddr));
 278                 memset(&np->rcv_saddr, 0, sizeof(np->rcv_saddr));
 279         }
 280 #endif
 281 }
 282
 283 #endif
 284
 285 extern int      ip_call_ra_chain(struct sk_buff *skb);
 286
 287 /*
 288  *      Functions provided by ip_fragment.o
 289  */
 290
 291 enum ip_defrag_users
 292 {
 293         IP_DEFRAG_LOCAL_DELIVER,
 294         IP_DEFRAG_CALL_RA_CHAIN,
 295         IP_DEFRAG_CONNTRACK_IN,
 296         IP_DEFRAG_CONNTRACK_OUT,
 297         IP_DEFRAG_NAT_OUT,
 298         IP_DEFRAG_VS_IN,
 299         IP_DEFRAG_VS_OUT,
 300         IP_DEFRAG_VS_FWD
 301 };
 302
 303 struct sk_buff *ip_defrag(struct sk_buff *skb, u32 user);
 304 extern int ip_frag_nqueues;
 305 extern atomic_t ip_frag_mem;
 306
 307 /*
 308  *      Functions provided by ip_forward.c
 309  */
 310
 311 extern int ip_forward(struct sk_buff *skb);
 312 extern int ip_net_unreachable(struct sk_buff *skb);
 313
 314 /*
 315  *      Functions provided by ip_options.c
 316  */
 317
 318 extern void ip_options_build(struct sk_buff *skb, struct ip_options *opt, u32 daddr, struct rtable *rt, int is_frag);
 319 extern int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb);
 320 extern void ip_options_fragment(struct sk_buff *skb);
 321 extern int ip_options_compile(struct ip_options *opt, struct sk_buff *skb);
 322 extern int ip_options_get(struct ip_options **optp, unsigned char *data, int optlen, int user);
 323 extern void ip_options_undo(struct ip_options * opt);
 324 extern void ip_forward_options(struct sk_buff *skb);
 325 extern int ip_options_rcv_srr(struct sk_buff *skb);
 326
 327 /*
 328  *      Functions provided by ip_sockglue.c
 329  */
 330
 331 extern void     ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb);
 332 extern int      ip_cmsg_send(struct msghdr *msg, struct ipcm_cookie *ipc);
 333 extern int      ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval, int optlen);
 334 extern int      ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval, int __user *optlen);
 335 extern int      ip_ra_control(struct sock *sk, unsigned char on, void (*destructor)(struct sock *));
 336
 337 extern int      ip_recv_error(struct sock *sk, struct msghdr *msg, int len);
 338 extern void     ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err,
 339                               u16 port, u32 info, u8 *payload);
 340 extern void     ip_local_error(struct sock *sk, int err, u32 daddr, u16 dport,
 341                                u32 info);
 342
 343 /* sysctl helpers - any sysctl which holds a value that ends up being
 344  * fed into the routing cache should use these handlers.
 345  */
 346 int ipv4_doint_and_flush(ctl_table *ctl, int write,
 347                          struct file* filp, void __user *buffer,
 348                          size_t *lenp, loff_t *ppos);
 349 int ipv4_doint_and_flush_strategy(ctl_table *table, int __user *name, int nlen,
 350                                   void __user *oldval, size_t __user *oldlenp,
 351                                   void __user *newval, size_t newlen,
 352                                   void **context);
 353
 354 #endif  /* _IP_H */