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, <bir7@leland.Stanford.Edu>
  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 **pskb);
  93 extern int              ip_mc_output(struct sk_buff **pskb);
  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
 113 /*
 114  *      Map a multicast IP onto multicast MAC for type Token Ring.
 115  *      This conforms to RFC1469 Option 2 Multicasting i.e.
 116  *      using a functional address to transmit / receive
 117  *      multicast packets.
 118  */
 119
 120 static inline void ip_tr_mc_map(u32 addr, char *buf)
 121 {
 122         buf[0]=0xC0;
 123         buf[1]=0x00;
 124         buf[2]=0x00;
 125         buf[3]=0x04;
 126         buf[4]=0x00;
 127         buf[5]=0x00;
 128 }
 129
 130 struct ip_reply_arg {
 131         struct iovec iov[1];
 132         u32          csum;
 133         int          csumoffset; /* u16 offset of csum in iov[0].iov_base */
 134                                  /* -1 if not needed */
 135 };
 136
 137 void ip_send_reply(struct sock *sk, struct sk_buff *skb, struct ip_reply_arg *arg,
 138                    unsigned int len);
 139
 140 extern int ip_finish_output(struct sk_buff *skb);
 141
 142 struct ipv4_config
 143 {
 144         int     log_martians;
 145         int     autoconfig;
 146         int     no_pmtu_disc;
 147 };
 148
 149 extern struct ipv4_config ipv4_config;
 150 DECLARE_SNMP_STAT(struct ipstats_mib, ip_statistics);
 151 #define IP_INC_STATS(field)             SNMP_INC_STATS(ip_statistics, field)
 152 #define IP_INC_STATS_BH(field)          SNMP_INC_STATS_BH(ip_statistics, field)
 153 #define IP_INC_STATS_USER(field)        SNMP_INC_STATS_USER(ip_statistics, field)
 154 DECLARE_SNMP_STAT(struct linux_mib, net_statistics);
 155 #define NET_INC_STATS(field)            SNMP_INC_STATS(net_statistics, field)
 156 #define NET_INC_STATS_BH(field)         SNMP_INC_STATS_BH(net_statistics, field)
 157 #define NET_INC_STATS_USER(field)       SNMP_INC_STATS_USER(net_statistics, field)
 158 #define NET_ADD_STATS_BH(field, adnd)   SNMP_ADD_STATS_BH(net_statistics, field, adnd)
 159 #define NET_ADD_STATS_USER(field, adnd) SNMP_ADD_STATS_USER(net_statistics, field, adnd)
 160
 161 extern int sysctl_local_port_range[2];
 162 extern int sysctl_ip_default_ttl;
 163
 164 #ifdef CONFIG_INET
 165 /* The function in 2.2 was invalid, producing wrong result for
 166  * check=0xFEFF. It was noticed by Arthur Skawina _year_ ago. --ANK(000625) */
 167 static inline
 168 int ip_decrease_ttl(struct iphdr *iph)
 169 {
 170         u32 check = iph->check;
 171         check += htons(0x0100);
 172         iph->check = check + (check>=0xFFFF);
 173         return --iph->ttl;
 174 }
 175
 176 static inline
 177 int ip_dont_fragment(struct sock *sk, struct dst_entry *dst)
 178 {
 179         return (inet_sk(sk)->pmtudisc == IP_PMTUDISC_DO ||
 180                 (inet_sk(sk)->pmtudisc == IP_PMTUDISC_WANT &&
 181                  !(dst_metric(dst, RTAX_LOCK)&(1<<RTAX_MTU))));
 182 }
 183
 184 extern void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more);
 185
 186 static inline void ip_select_ident(struct iphdr *iph, struct dst_entry *dst, struct sock *sk)
 187 {
 188         if (iph->frag_off & htons(IP_DF)) {
 189                 /* This is only to work around buggy Windows95/2000
 190                  * VJ compression implementations.  If the ID field
 191                  * does not change, they drop every other packet in
 192                  * a TCP stream using header compression.
 193                  */
 194                 iph->id = (sk && inet_sk(sk)->daddr) ?
 195                                         htons(inet_sk(sk)->id++) : 0;
 196         } else
 197                 __ip_select_ident(iph, dst, 0);
 198 }
 199
 200 static inline void ip_select_ident_more(struct iphdr *iph, struct dst_entry *dst, struct sock *sk, int more)
 201 {
 202         if (iph->frag_off & htons(IP_DF)) {
 203                 if (sk && inet_sk(sk)->daddr) {
 204                         iph->id = htons(inet_sk(sk)->id);
 205                         inet_sk(sk)->id += 1 + more;
 206                 } else
 207                         iph->id = 0;
 208         } else
 209                 __ip_select_ident(iph, dst, more);
 210 }
 211
 212 /*
 213  *      Map a multicast IP onto multicast MAC for type ethernet.
 214  */
 215
 216 static inline void ip_eth_mc_map(u32 addr, char *buf)
 217 {
 218         addr=ntohl(addr);
 219         buf[0]=0x01;
 220         buf[1]=0x00;
 221         buf[2]=0x5e;
 222         buf[5]=addr&0xFF;
 223         addr>>=8;
 224         buf[4]=addr&0xFF;
 225         addr>>=8;
 226         buf[3]=addr&0x7F;
 227 }
 228
 229 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 230 #include <linux/ipv6.h>
 231 #endif
 232
 233 static __inline__ void inet_reset_saddr(struct sock *sk)
 234 {
 235         inet_sk(sk)->rcv_saddr = inet_sk(sk)->saddr = 0;
 236 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 237         if (sk->sk_family == PF_INET6) {
 238                 struct ipv6_pinfo *np = inet6_sk(sk);
 239
 240                 memset(&np->saddr, 0, sizeof(np->saddr));
 241                 memset(&np->rcv_saddr, 0, sizeof(np->rcv_saddr));
 242         }
 243 #endif
 244 }
 245
 246 #endif
 247
 248 extern int      ip_call_ra_chain(struct sk_buff *skb);
 249
 250 /*
 251  *      Functions provided by ip_fragment.o
 252  */
 253
 254 struct sk_buff *ip_defrag(struct sk_buff *skb);
 255 extern int ip_frag_nqueues;
 256 extern atomic_t ip_frag_mem;
 257
 258 /*
 259  *      Functions provided by ip_forward.c
 260  */
 261
 262 extern int ip_forward(struct sk_buff *skb);
 263 extern int ip_net_unreachable(struct sk_buff *skb);
 264
 265 /*
 266  *      Functions provided by ip_options.c
 267  */
 268
 269 extern void ip_options_build(struct sk_buff *skb, struct ip_options *opt, u32 daddr, struct rtable *rt, int is_frag);
 270 extern int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb);
 271 extern void ip_options_fragment(struct sk_buff *skb);
 272 extern int ip_options_compile(struct ip_options *opt, struct sk_buff *skb);
 273 extern int ip_options_get(struct ip_options **optp, unsigned char *data, int optlen, int user);
 274 extern void ip_options_undo(struct ip_options * opt);
 275 extern void ip_forward_options(struct sk_buff *skb);
 276 extern int ip_options_rcv_srr(struct sk_buff *skb);
 277
 278 /*
 279  *      Functions provided by ip_sockglue.c
 280  */
 281
 282 extern void     ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb);
 283 extern int      ip_cmsg_send(struct msghdr *msg, struct ipcm_cookie *ipc);
 284 extern int      ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval, int optlen);
 285 extern int      ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval, int __user *optlen);
 286 extern int      ip_ra_control(struct sock *sk, unsigned char on, void (*destructor)(struct sock *));
 287
 288 extern int      ip_recv_error(struct sock *sk, struct msghdr *msg, int len);
 289 extern void     ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err,
 290                               u16 port, u32 info, u8 *payload);
 291 extern void     ip_local_error(struct sock *sk, int err, u32 daddr, u16 dport,
 292                                u32 info);
 293
 294 extern int ipv4_proc_init(void);
 295
 296 /* sysctl helpers - any sysctl which holds a value that ends up being
 297  * fed into the routing cache should use these handlers.
 298  */
 299 int ipv4_doint_and_flush(ctl_table *ctl, int write,
 300                          struct file* filp, void __user *buffer,
 301                          size_t *lenp);
 302 int ipv4_doint_and_flush_strategy(ctl_table *table, int __user *name, int nlen,
 303                                   void __user *oldval, size_t __user *oldlenp,
 304                                   void __user *newval, size_t newlen,
 305                                   void **context);
 306
 307 #endif  /* _IP_H */