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 #include <net/flow.h>
  33
  34 struct sock;
  35
  36 struct 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
  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         __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
  61 struct 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
  71 extern 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
  81 struct msghdr;
  82 struct net_device;
  83 struct packet_type;
  84 struct rtable;
  85 struct sockaddr;
  86
  87 extern int              igmp_mc_proc_init(void);
  88
  89 /*
  90  *      Functions provided by ip.c
  91  */
  92
  93 extern int              ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk,
  94                                               __be32 saddr, __be32 daddr,
  95                                               struct ip_options_rcu *opt);
  96 extern int              ip_rcv(struct sk_buff *skb, struct net_device *dev,
  97                                struct packet_type *pt, struct net_device *orig_dev);
  98 extern int              ip_local_deliver(struct sk_buff *skb);
  99 extern int              ip_mr_input(struct sk_buff *skb);
 100 extern int              ip_output(struct sk_buff *skb);
 101 extern int              ip_mc_output(struct sk_buff *skb);
 102 extern int              ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *));
 103 extern int              ip_do_nat(struct sk_buff *skb);
 104 extern void             ip_send_check(struct iphdr *ip);
 105 extern int              __ip_local_out(struct sk_buff *skb);
 106 extern int              ip_local_out(struct sk_buff *skb);
 107 extern int              ip_queue_xmit(struct sk_buff *skb, struct flowi *fl);
 108 extern void             ip_init(void);
 109 extern 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);
 116 extern int              ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb);
 117 extern ssize_t          ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,
 118                                 int offset, size_t size, int flags);
 119 extern struct sk_buff  *__ip_make_skb(struct sock *sk,
 120                                       struct flowi4 *fl4,
 121                                       struct sk_buff_head *queue,
 122                                       struct inet_cork *cork);
 123 extern int              ip_send_skb(struct sk_buff *skb);
 124 extern int              ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4);
 125 extern void             ip_flush_pending_frames(struct sock *sk);
 126 extern 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
 135 static 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 */
 141 extern int              ip4_datagram_connect(struct sock *sk,
 142                                              struct sockaddr *uaddr, int addr_len);
 143
 144 /*
 145  *      Map a multicast IP onto multicast MAC for type Token Ring.
 146  *      This conforms to RFC1469 Option 2 Multicasting i.e.
 147  *      using a functional address to transmit / receive
 148  *      multicast packets.
 149  */
 150
 151 static inline void ip_tr_mc_map(__be32 addr, char *buf)
 152 {
 153         buf[0]=0xC0;
 154         buf[1]=0x00;
 155         buf[2]=0x00;
 156         buf[3]=0x04;
 157         buf[4]=0x00;
 158         buf[5]=0x00;
 159 }
 160
 161 struct ip_reply_arg {
 162         struct kvec iov[1];
 163         int         flags;
 164         __wsum      csum;
 165         int         csumoffset; /* u16 offset of csum in iov[0].iov_base */
 166                                 /* -1 if not needed */
 167         int         bound_dev_if;
 168 };
 169
 170 #define IP_REPLY_ARG_NOSRCCHECK 1
 171
 172 static inline __u8 ip_reply_arg_flowi_flags(const struct ip_reply_arg *arg)
 173 {
 174         return (arg->flags & IP_REPLY_ARG_NOSRCCHECK) ? FLOWI_FLAG_ANYSRC : 0;
 175 }
 176
 177 void ip_send_reply(struct sock *sk, struct sk_buff *skb, __be32 daddr,
 178                    struct ip_reply_arg *arg, unsigned int len);
 179
 180 struct ipv4_config {
 181         int     log_martians;
 182         int     no_pmtu_disc;
 183 };
 184
 185 extern struct ipv4_config ipv4_config;
 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_BH(net, field, adnd) SNMP_ADD_STATS_BH((net)->mib.net_statistics, field, adnd)
 196 #define NET_ADD_STATS_USER(net, field, adnd) SNMP_ADD_STATS_USER((net)->mib.net_statistics, field, adnd)
 197
 198 extern unsigned long snmp_fold_field(void __percpu *mib[], int offt);
 199 #if BITS_PER_LONG==32
 200 extern u64 snmp_fold_field64(void __percpu *mib[], int offt, size_t sync_off);
 201 #else
 202 static inline u64 snmp_fold_field64(void __percpu *mib[], int offt, size_t syncp_off)
 203 {
 204         return snmp_fold_field(mib, offt);
 205 }
 206 #endif
 207 extern int snmp_mib_init(void __percpu *ptr[2], size_t mibsize, size_t align);
 208 extern void snmp_mib_free(void __percpu *ptr[2]);
 209
 210 extern struct local_ports {
 211         seqlock_t       lock;
 212         int             range[2];
 213 } sysctl_local_ports;
 214 extern void inet_get_local_port_range(int *low, int *high);
 215
 216 extern unsigned long *sysctl_local_reserved_ports;
 217 static inline int inet_is_reserved_local_port(int port)
 218 {
 219         return test_bit(port, sysctl_local_reserved_ports);
 220 }
 221
 222 extern int sysctl_ip_nonlocal_bind;
 223
 224 extern struct ctl_path net_core_path[];
 225 extern struct ctl_path net_ipv4_ctl_path[];
 226
 227 /* From inetpeer.c */
 228 extern int inet_peer_threshold;
 229 extern int inet_peer_minttl;
 230 extern int inet_peer_maxttl;
 231
 232 /* From ip_output.c */
 233 extern int sysctl_ip_dynaddr;
 234
 235 extern void ipfrag_init(void);
 236
 237 extern void ip_static_sysctl_init(void);
 238
 239 static inline bool ip_is_fragment(const struct iphdr *iph)
 240 {
 241         return (iph->frag_off & htons(IP_MF | IP_OFFSET)) != 0;
 242 }
 243
 244 #ifdef CONFIG_INET
 245 #include <net/dst.h>
 246
 247 /* The function in 2.2 was invalid, producing wrong result for
 248  * check=0xFEFF. It was noticed by Arthur Skawina _year_ ago. --ANK(000625) */
 249 static inline
 250 int ip_decrease_ttl(struct iphdr *iph)
 251 {
 252         u32 check = (__force u32)iph->check;
 253         check += (__force u32)htons(0x0100);
 254         iph->check = (__force __sum16)(check + (check>=0xFFFF));
 255         return --iph->ttl;
 256 }
 257
 258 static inline
 259 int ip_dont_fragment(struct sock *sk, struct dst_entry *dst)
 260 {
 261         return  inet_sk(sk)->pmtudisc == IP_PMTUDISC_DO ||
 262                 (inet_sk(sk)->pmtudisc == IP_PMTUDISC_WANT &&
 263                  !(dst_metric_locked(dst, RTAX_MTU)));
 264 }
 265
 266 extern void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more);
 267
 268 static inline void ip_select_ident(struct iphdr *iph, struct dst_entry *dst, struct sock *sk)
 269 {
 270         if (iph->frag_off & htons(IP_DF)) {
 271                 /* This is only to work around buggy Windows95/2000
 272                  * VJ compression implementations.  If the ID field
 273                  * does not change, they drop every other packet in
 274                  * a TCP stream using header compression.
 275                  */
 276                 iph->id = (sk && inet_sk(sk)->inet_daddr) ?
 277                                         htons(inet_sk(sk)->inet_id++) : 0;
 278         } else
 279                 __ip_select_ident(iph, dst, 0);
 280 }
 281
 282 static inline void ip_select_ident_more(struct iphdr *iph, struct dst_entry *dst, struct sock *sk, int more)
 283 {
 284         if (iph->frag_off & htons(IP_DF)) {
 285                 if (sk && inet_sk(sk)->inet_daddr) {
 286                         iph->id = htons(inet_sk(sk)->inet_id);
 287                         inet_sk(sk)->inet_id += 1 + more;
 288                 } else
 289                         iph->id = 0;
 290         } else
 291                 __ip_select_ident(iph, dst, more);
 292 }
 293
 294 /*
 295  *      Map a multicast IP onto multicast MAC for type ethernet.
 296  */
 297
 298 static inline void ip_eth_mc_map(__be32 naddr, char *buf)
 299 {
 300         __u32 addr=ntohl(naddr);
 301         buf[0]=0x01;
 302         buf[1]=0x00;
 303         buf[2]=0x5e;
 304         buf[5]=addr&0xFF;
 305         addr>>=8;
 306         buf[4]=addr&0xFF;
 307         addr>>=8;
 308         buf[3]=addr&0x7F;
 309 }
 310
 311 /*
 312  *      Map a multicast IP onto multicast MAC for type IP-over-InfiniBand.
 313  *      Leave P_Key as 0 to be filled in by driver.
 314  */
 315
 316 static inline void ip_ib_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
 317 {
 318         __u32 addr;
 319         unsigned char scope = broadcast[5] & 0xF;
 320
 321         buf[0]  = 0;            /* Reserved */
 322         buf[1]  = 0xff;         /* Multicast QPN */
 323         buf[2]  = 0xff;
 324         buf[3]  = 0xff;
 325         addr    = ntohl(naddr);
 326         buf[4]  = 0xff;
 327         buf[5]  = 0x10 | scope; /* scope from broadcast address */
 328         buf[6]  = 0x40;         /* IPv4 signature */
 329         buf[7]  = 0x1b;
 330         buf[8]  = broadcast[8];         /* P_Key */
 331         buf[9]  = broadcast[9];
 332         buf[10] = 0;
 333         buf[11] = 0;
 334         buf[12] = 0;
 335         buf[13] = 0;
 336         buf[14] = 0;
 337         buf[15] = 0;
 338         buf[19] = addr & 0xff;
 339         addr  >>= 8;
 340         buf[18] = addr & 0xff;
 341         addr  >>= 8;
 342         buf[17] = addr & 0xff;
 343         addr  >>= 8;
 344         buf[16] = addr & 0x0f;
 345 }
 346
 347 static inline void ip_ipgre_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
 348 {
 349         if ((broadcast[0] | broadcast[1] | broadcast[2] | broadcast[3]) != 0)
 350                 memcpy(buf, broadcast, 4);
 351         else
 352                 memcpy(buf, &naddr, sizeof(naddr));
 353 }
 354
 355 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 356 #include <linux/ipv6.h>
 357 #endif
 358
 359 static __inline__ void inet_reset_saddr(struct sock *sk)
 360 {
 361         inet_sk(sk)->inet_rcv_saddr = inet_sk(sk)->inet_saddr = 0;
 362 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 363         if (sk->sk_family == PF_INET6) {
 364                 struct ipv6_pinfo *np = inet6_sk(sk);
 365
 366                 memset(&np->saddr, 0, sizeof(np->saddr));
 367                 memset(&np->rcv_saddr, 0, sizeof(np->rcv_saddr));
 368         }
 369 #endif
 370 }
 371
 372 #endif
 373
 374 static inline int sk_mc_loop(struct sock *sk)
 375 {
 376         if (!sk)
 377                 return 1;
 378         switch (sk->sk_family) {
 379         case AF_INET:
 380                 return inet_sk(sk)->mc_loop;
 381 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 382         case AF_INET6:
 383                 return inet6_sk(sk)->mc_loop;
 384 #endif
 385         }
 386         WARN_ON(1);
 387         return 1;
 388 }
 389
 390 extern int      ip_call_ra_chain(struct sk_buff *skb);
 391
 392 /*
 393  *      Functions provided by ip_fragment.c
 394  */
 395
 396 enum ip_defrag_users {
 397         IP_DEFRAG_LOCAL_DELIVER,
 398         IP_DEFRAG_CALL_RA_CHAIN,
 399         IP_DEFRAG_CONNTRACK_IN,
 400         __IP_DEFRAG_CONNTRACK_IN_END    = IP_DEFRAG_CONNTRACK_IN + USHRT_MAX,
 401         IP_DEFRAG_CONNTRACK_OUT,
 402         __IP_DEFRAG_CONNTRACK_OUT_END   = IP_DEFRAG_CONNTRACK_OUT + USHRT_MAX,
 403         IP_DEFRAG_CONNTRACK_BRIDGE_IN,
 404         __IP_DEFRAG_CONNTRACK_BRIDGE_IN = IP_DEFRAG_CONNTRACK_BRIDGE_IN + USHRT_MAX,
 405         IP_DEFRAG_VS_IN,
 406         IP_DEFRAG_VS_OUT,
 407         IP_DEFRAG_VS_FWD,
 408         IP_DEFRAG_AF_PACKET,
 409 };
 410
 411 int ip_defrag(struct sk_buff *skb, u32 user);
 412 int ip_frag_mem(struct net *net);
 413 int ip_frag_nqueues(struct net *net);
 414
 415 /*
 416  *      Functions provided by ip_forward.c
 417  */
 418
 419 extern int ip_forward(struct sk_buff *skb);
 420
 421 /*
 422  *      Functions provided by ip_options.c
 423  */
 424
 425 extern void ip_options_build(struct sk_buff *skb, struct ip_options *opt,
 426                              __be32 daddr, struct rtable *rt, int is_frag);
 427 extern int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb);
 428 extern void ip_options_fragment(struct sk_buff *skb);
 429 extern int ip_options_compile(struct net *net,
 430                               struct ip_options *opt, struct sk_buff *skb);
 431 extern int ip_options_get(struct net *net, struct ip_options_rcu **optp,
 432                           unsigned char *data, int optlen);
 433 extern int ip_options_get_from_user(struct net *net, struct ip_options_rcu **optp,
 434                                     unsigned char __user *data, int optlen);
 435 extern void ip_options_undo(struct ip_options * opt);
 436 extern void ip_forward_options(struct sk_buff *skb);
 437 extern int ip_options_rcv_srr(struct sk_buff *skb);
 438
 439 /*
 440  *      Functions provided by ip_sockglue.c
 441  */
 442
 443 extern int      ip_queue_rcv_skb(struct sock *sk, struct sk_buff *skb);
 444 extern void     ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb);
 445 extern int      ip_cmsg_send(struct net *net,
 446                              struct msghdr *msg, struct ipcm_cookie *ipc);
 447 extern int      ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval, unsigned int optlen);
 448 extern int      ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval, int __user *optlen);
 449 extern int      compat_ip_setsockopt(struct sock *sk, int level,
 450                         int optname, char __user *optval, unsigned int optlen);
 451 extern int      compat_ip_getsockopt(struct sock *sk, int level,
 452                         int optname, char __user *optval, int __user *optlen);
 453 extern int      ip_ra_control(struct sock *sk, unsigned char on, void (*destructor)(struct sock *));
 454
 455 extern int      ip_recv_error(struct sock *sk, struct msghdr *msg, int len);
 456 extern void     ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err,
 457                               __be16 port, u32 info, u8 *payload);
 458 extern void     ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 dport,
 459                                u32 info);
 460
 461 #ifdef CONFIG_PROC_FS
 462 extern int ip_misc_proc_init(void);
 463 #endif
 464
 465 #endif  /* _IP_H */