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       *opt;
  56         union skb_shared_tx     shtx;
  57 };
  58
  59 #define IPCB(skb) ((struct inet_skb_parm*)((skb)->cb))
  60
  61 struct ip_ra_chain {
  62         struct ip_ra_chain      *next;
  63         struct sock             *sk;
  64         void                    (*destructor)(struct sock *);
  65 };
  66
  67 extern struct ip_ra_chain *ip_ra_chain;
  68 extern rwlock_t ip_ra_lock;
  69
  70 /* IP flags. */
  71 #define IP_CE           0x8000          /* Flag: "Congestion"           */
  72 #define IP_DF           0x4000          /* Flag: "Don't Fragment"       */
  73 #define IP_MF           0x2000          /* Flag: "More Fragments"       */
  74 #define IP_OFFSET       0x1FFF          /* "Fragment Offset" part       */
  75
  76 #define IP_FRAG_TIME    (30 * HZ)               /* fragment lifetime    */
  77
  78 struct msghdr;
  79 struct net_device;
  80 struct packet_type;
  81 struct rtable;
  82 struct sockaddr;
  83
  84 extern int              igmp_mc_proc_init(void);
  85
  86 /*
  87  *      Functions provided by ip.c
  88  */
  89
  90 extern int              ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk,
  91                                               __be32 saddr, __be32 daddr,
  92                                               struct ip_options *opt);
  93 extern int              ip_rcv(struct sk_buff *skb, struct net_device *dev,
  94                                struct packet_type *pt, struct net_device *orig_dev);
  95 extern int              ip_local_deliver(struct sk_buff *skb);
  96 extern int              ip_mr_input(struct sk_buff *skb);
  97 extern int              ip_output(struct sk_buff *skb);
  98 extern int              ip_mc_output(struct sk_buff *skb);
  99 extern int              ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *));
 100 extern int              ip_do_nat(struct sk_buff *skb);
 101 extern void             ip_send_check(struct iphdr *ip);
 102 extern int              __ip_local_out(struct sk_buff *skb);
 103 extern int              ip_local_out(struct sk_buff *skb);
 104 extern int              ip_queue_xmit(struct sk_buff *skb, int ipfragok);
 105 extern void             ip_init(void);
 106 extern int              ip_append_data(struct sock *sk,
 107                                        int getfrag(void *from, char *to, int offset, int len,
 108                                                    int odd, struct sk_buff *skb),
 109                                 void *from, int len, int protolen,
 110                                 struct ipcm_cookie *ipc,
 111                                 struct rtable **rt,
 112                                 unsigned int flags);
 113 extern int              ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb);
 114 extern ssize_t          ip_append_page(struct sock *sk, struct page *page,
 115                                 int offset, size_t size, int flags);
 116 extern int              ip_push_pending_frames(struct sock *sk);
 117 extern void             ip_flush_pending_frames(struct sock *sk);
 118
 119 /* datagram.c */
 120 extern int              ip4_datagram_connect(struct sock *sk,
 121                                              struct sockaddr *uaddr, int addr_len);
 122
 123 /*
 124  *      Map a multicast IP onto multicast MAC for type Token Ring.
 125  *      This conforms to RFC1469 Option 2 Multicasting i.e.
 126  *      using a functional address to transmit / receive
 127  *      multicast packets.
 128  */
 129
 130 static inline void ip_tr_mc_map(__be32 addr, char *buf)
 131 {
 132         buf[0]=0xC0;
 133         buf[1]=0x00;
 134         buf[2]=0x00;
 135         buf[3]=0x04;
 136         buf[4]=0x00;
 137         buf[5]=0x00;
 138 }
 139
 140 struct ip_reply_arg {
 141         struct kvec iov[1];
 142         int         flags;
 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 #define IP_REPLY_ARG_NOSRCCHECK 1
 150
 151 static inline __u8 ip_reply_arg_flowi_flags(const struct ip_reply_arg *arg)
 152 {
 153         return (arg->flags & IP_REPLY_ARG_NOSRCCHECK) ? FLOWI_FLAG_ANYSRC : 0;
 154 }
 155
 156 void ip_send_reply(struct sock *sk, struct sk_buff *skb, struct ip_reply_arg *arg,
 157                    unsigned int len);
 158
 159 struct ipv4_config {
 160         int     log_martians;
 161         int     no_pmtu_disc;
 162 };
 163
 164 extern struct ipv4_config ipv4_config;
 165 #define IP_INC_STATS(net, field)        SNMP_INC_STATS((net)->mib.ip_statistics, field)
 166 #define IP_INC_STATS_BH(net, field)     SNMP_INC_STATS_BH((net)->mib.ip_statistics, field)
 167 #define IP_ADD_STATS(net, field, val)   SNMP_ADD_STATS((net)->mib.ip_statistics, field, val)
 168 #define IP_ADD_STATS_BH(net, field, val) SNMP_ADD_STATS_BH((net)->mib.ip_statistics, field, val)
 169 #define IP_UPD_PO_STATS(net, field, val) SNMP_UPD_PO_STATS((net)->mib.ip_statistics, field, val)
 170 #define IP_UPD_PO_STATS_BH(net, field, val) SNMP_UPD_PO_STATS_BH((net)->mib.ip_statistics, field, val)
 171 #define NET_INC_STATS(net, field)       SNMP_INC_STATS((net)->mib.net_statistics, field)
 172 #define NET_INC_STATS_BH(net, field)    SNMP_INC_STATS_BH((net)->mib.net_statistics, field)
 173 #define NET_INC_STATS_USER(net, field)  SNMP_INC_STATS_USER((net)->mib.net_statistics, field)
 174 #define NET_ADD_STATS_BH(net, field, adnd) SNMP_ADD_STATS_BH((net)->mib.net_statistics, field, adnd)
 175 #define NET_ADD_STATS_USER(net, field, adnd) SNMP_ADD_STATS_USER((net)->mib.net_statistics, field, adnd)
 176
 177 extern unsigned long snmp_fold_field(void *mib[], int offt);
 178 extern int snmp_mib_init(void *ptr[2], size_t mibsize);
 179 extern void snmp_mib_free(void *ptr[2]);
 180
 181 extern struct local_ports {
 182         seqlock_t       lock;
 183         int             range[2];
 184 } sysctl_local_ports;
 185 extern void inet_get_local_port_range(int *low, int *high);
 186
 187 extern int sysctl_ip_default_ttl;
 188 extern int sysctl_ip_nonlocal_bind;
 189
 190 extern struct ctl_path net_core_path[];
 191 extern struct ctl_path net_ipv4_ctl_path[];
 192
 193 /* From inetpeer.c */
 194 extern int inet_peer_threshold;
 195 extern int inet_peer_minttl;
 196 extern int inet_peer_maxttl;
 197 extern int inet_peer_gc_mintime;
 198 extern int inet_peer_gc_maxtime;
 199
 200 /* From ip_output.c */
 201 extern int sysctl_ip_dynaddr;
 202
 203 extern void ipfrag_init(void);
 204
 205 extern void ip_static_sysctl_init(void);
 206
 207 #ifdef CONFIG_INET
 208 #include <net/dst.h>
 209
 210 /* The function in 2.2 was invalid, producing wrong result for
 211  * check=0xFEFF. It was noticed by Arthur Skawina _year_ ago. --ANK(000625) */
 212 static inline
 213 int ip_decrease_ttl(struct iphdr *iph)
 214 {
 215         u32 check = (__force u32)iph->check;
 216         check += (__force u32)htons(0x0100);
 217         iph->check = (__force __sum16)(check + (check>=0xFFFF));
 218         return --iph->ttl;
 219 }
 220
 221 static inline
 222 int ip_dont_fragment(struct sock *sk, struct dst_entry *dst)
 223 {
 224         return (inet_sk(sk)->pmtudisc == IP_PMTUDISC_DO ||
 225                 (inet_sk(sk)->pmtudisc == IP_PMTUDISC_WANT &&
 226                  !(dst_metric_locked(dst, RTAX_MTU))));
 227 }
 228
 229 extern void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more);
 230
 231 static inline void ip_select_ident(struct iphdr *iph, struct dst_entry *dst, struct sock *sk)
 232 {
 233         if (iph->frag_off & htons(IP_DF)) {
 234                 /* This is only to work around buggy Windows95/2000
 235                  * VJ compression implementations.  If the ID field
 236                  * does not change, they drop every other packet in
 237                  * a TCP stream using header compression.
 238                  */
 239                 iph->id = (sk && inet_sk(sk)->inet_daddr) ?
 240                                         htons(inet_sk(sk)->inet_id++) : 0;
 241         } else
 242                 __ip_select_ident(iph, dst, 0);
 243 }
 244
 245 static inline void ip_select_ident_more(struct iphdr *iph, struct dst_entry *dst, struct sock *sk, int more)
 246 {
 247         if (iph->frag_off & htons(IP_DF)) {
 248                 if (sk && inet_sk(sk)->inet_daddr) {
 249                         iph->id = htons(inet_sk(sk)->inet_id);
 250                         inet_sk(sk)->inet_id += 1 + more;
 251                 } else
 252                         iph->id = 0;
 253         } else
 254                 __ip_select_ident(iph, dst, more);
 255 }
 256
 257 /*
 258  *      Map a multicast IP onto multicast MAC for type ethernet.
 259  */
 260
 261 static inline void ip_eth_mc_map(__be32 naddr, char *buf)
 262 {
 263         __u32 addr=ntohl(naddr);
 264         buf[0]=0x01;
 265         buf[1]=0x00;
 266         buf[2]=0x5e;
 267         buf[5]=addr&0xFF;
 268         addr>>=8;
 269         buf[4]=addr&0xFF;
 270         addr>>=8;
 271         buf[3]=addr&0x7F;
 272 }
 273
 274 /*
 275  *      Map a multicast IP onto multicast MAC for type IP-over-InfiniBand.
 276  *      Leave P_Key as 0 to be filled in by driver.
 277  */
 278
 279 static inline void ip_ib_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
 280 {
 281         __u32 addr;
 282         unsigned char scope = broadcast[5] & 0xF;
 283
 284         buf[0]  = 0;            /* Reserved */
 285         buf[1]  = 0xff;         /* Multicast QPN */
 286         buf[2]  = 0xff;
 287         buf[3]  = 0xff;
 288         addr    = ntohl(naddr);
 289         buf[4]  = 0xff;
 290         buf[5]  = 0x10 | scope; /* scope from broadcast address */
 291         buf[6]  = 0x40;         /* IPv4 signature */
 292         buf[7]  = 0x1b;
 293         buf[8]  = broadcast[8];         /* P_Key */
 294         buf[9]  = broadcast[9];
 295         buf[10] = 0;
 296         buf[11] = 0;
 297         buf[12] = 0;
 298         buf[13] = 0;
 299         buf[14] = 0;
 300         buf[15] = 0;
 301         buf[19] = addr & 0xff;
 302         addr  >>= 8;
 303         buf[18] = addr & 0xff;
 304         addr  >>= 8;
 305         buf[17] = addr & 0xff;
 306         addr  >>= 8;
 307         buf[16] = addr & 0x0f;
 308 }
 309
 310 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 311 #include <linux/ipv6.h>
 312 #endif
 313
 314 static __inline__ void inet_reset_saddr(struct sock *sk)
 315 {
 316         inet_sk(sk)->inet_rcv_saddr = inet_sk(sk)->inet_saddr = 0;
 317 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 318         if (sk->sk_family == PF_INET6) {
 319                 struct ipv6_pinfo *np = inet6_sk(sk);
 320
 321                 memset(&np->saddr, 0, sizeof(np->saddr));
 322                 memset(&np->rcv_saddr, 0, sizeof(np->rcv_saddr));
 323         }
 324 #endif
 325 }
 326
 327 #endif
 328
 329 extern int      ip_call_ra_chain(struct sk_buff *skb);
 330
 331 /*
 332  *      Functions provided by ip_fragment.c
 333  */
 334
 335 enum ip_defrag_users {
 336         IP_DEFRAG_LOCAL_DELIVER,
 337         IP_DEFRAG_CALL_RA_CHAIN,
 338         IP_DEFRAG_CONNTRACK_IN,
 339         IP_DEFRAG_CONNTRACK_OUT,
 340         IP_DEFRAG_CONNTRACK_BRIDGE_IN,
 341         IP_DEFRAG_VS_IN,
 342         IP_DEFRAG_VS_OUT,
 343         IP_DEFRAG_VS_FWD
 344 };
 345
 346 int ip_defrag(struct sk_buff *skb, u32 user);
 347 int ip_frag_mem(struct net *net);
 348 int ip_frag_nqueues(struct net *net);
 349
 350 /*
 351  *      Functions provided by ip_forward.c
 352  */
 353
 354 extern int ip_forward(struct sk_buff *skb);
 355
 356 /*
 357  *      Functions provided by ip_options.c
 358  */
 359
 360 extern void ip_options_build(struct sk_buff *skb, struct ip_options *opt, __be32 daddr, struct rtable *rt, int is_frag);
 361 extern int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb);
 362 extern void ip_options_fragment(struct sk_buff *skb);
 363 extern int ip_options_compile(struct net *net,
 364                               struct ip_options *opt, struct sk_buff *skb);
 365 extern int ip_options_get(struct net *net, struct ip_options **optp,
 366                           unsigned char *data, int optlen);
 367 extern int ip_options_get_from_user(struct net *net, struct ip_options **optp,
 368                                     unsigned char __user *data, int optlen);
 369 extern void ip_options_undo(struct ip_options * opt);
 370 extern void ip_forward_options(struct sk_buff *skb);
 371 extern int ip_options_rcv_srr(struct sk_buff *skb);
 372
 373 /*
 374  *      Functions provided by ip_sockglue.c
 375  */
 376
 377 extern void     ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb);
 378 extern int      ip_cmsg_send(struct net *net,
 379                              struct msghdr *msg, struct ipcm_cookie *ipc);
 380 extern int      ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval, unsigned int optlen);
 381 extern int      ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval, int __user *optlen);
 382 extern int      compat_ip_setsockopt(struct sock *sk, int level,
 383                         int optname, char __user *optval, unsigned int optlen);
 384 extern int      compat_ip_getsockopt(struct sock *sk, int level,
 385                         int optname, char __user *optval, int __user *optlen);
 386 extern int      ip_ra_control(struct sock *sk, unsigned char on, void (*destructor)(struct sock *));
 387
 388 extern int      ip_recv_error(struct sock *sk, struct msghdr *msg, int len);
 389 extern void     ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err,
 390                               __be16 port, u32 info, u8 *payload);
 391 extern void     ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 dport,
 392                                u32 info);
 393
 394 /* sysctl helpers - any sysctl which holds a value that ends up being
 395  * fed into the routing cache should use these handlers.
 396  */
 397 int ipv4_doint_and_flush(ctl_table *ctl, int write,
 398                          void __user *buffer,
 399                          size_t *lenp, loff_t *ppos);
 400 int ipv4_doint_and_flush_strategy(ctl_table *table,
 401                                   void __user *oldval, size_t __user *oldlenp,
 402                                   void __user *newval, size_t newlen);
 403 #ifdef CONFIG_PROC_FS
 404 extern int ip_misc_proc_init(void);
 405 #endif
 406
 407 #endif  /* _IP_H */