linux/include/net/route.h
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   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 router.
   7 *
   8 * Version:     @(#)route.h     1.0.4   05/27/93
   9 *
  10 * Authors:     Ross Biro
  11 *              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
  12 * Fixes:
  13 *              Alan Cox        :       Reformatted. Added ip_rt_local()
  14 *              Alan Cox        :       Support for TCP parameters.
  15 *              Alexey Kuznetsov:       Major changes for new routing code.
  16 *              Mike McLagan    :       Routing by source
  17 *              Robert Olsson   :       Added rt_cache statistics
  18 *
  19 *              This program is free software; you can redistribute it and/or
  20 *              modify it under the terms of the GNU General Public License
  21 *              as published by the Free Software Foundation; either version
  22 *              2 of the License, or (at your option) any later version.
  23 */
  24#ifndef _ROUTE_H
  25#define _ROUTE_H
  26
  27#include <net/dst.h>
  28#include <net/inetpeer.h>
  29#include <net/flow.h>
  30#include <net/inet_sock.h>
  31#include <linux/in_route.h>
  32#include <linux/rtnetlink.h>
  33#include <linux/rcupdate.h>
  34#include <linux/route.h>
  35#include <linux/ip.h>
  36#include <linux/cache.h>
  37#include <linux/security.h>
  38
  39#define RTO_ONLINK      0x01
  40
  41#define RT_CONN_FLAGS(sk)   (RT_TOS(inet_sk(sk)->tos) | sock_flag(sk, SOCK_LOCALROUTE))
  42
  43struct fib_nh;
  44struct fib_info;
  45struct rtable {
  46        struct dst_entry        dst;
  47
  48        int                     rt_genid;
  49        unsigned int            rt_flags;
  50        __u16                   rt_type;
  51        __u16                   rt_is_input;
  52
  53        int                     rt_iif;
  54
  55        /* Info on neighbour */
  56        __be32                  rt_gateway;
  57
  58        /* Miscellaneous cached information */
  59        u32                     rt_pmtu;
  60
  61        struct list_head        rt_uncached;
  62};
  63
  64static inline bool rt_is_input_route(const struct rtable *rt)
  65{
  66        return rt->rt_is_input != 0;
  67}
  68
  69static inline bool rt_is_output_route(const struct rtable *rt)
  70{
  71        return rt->rt_is_input == 0;
  72}
  73
  74static inline __be32 rt_nexthop(const struct rtable *rt, __be32 daddr)
  75{
  76        if (rt->rt_gateway)
  77                return rt->rt_gateway;
  78        return daddr;
  79}
  80
  81struct ip_rt_acct {
  82        __u32   o_bytes;
  83        __u32   o_packets;
  84        __u32   i_bytes;
  85        __u32   i_packets;
  86};
  87
  88struct rt_cache_stat {
  89        unsigned int in_hit;
  90        unsigned int in_slow_tot;
  91        unsigned int in_slow_mc;
  92        unsigned int in_no_route;
  93        unsigned int in_brd;
  94        unsigned int in_martian_dst;
  95        unsigned int in_martian_src;
  96        unsigned int out_hit;
  97        unsigned int out_slow_tot;
  98        unsigned int out_slow_mc;
  99        unsigned int gc_total;
 100        unsigned int gc_ignored;
 101        unsigned int gc_goal_miss;
 102        unsigned int gc_dst_overflow;
 103        unsigned int in_hlist_search;
 104        unsigned int out_hlist_search;
 105};
 106
 107extern struct ip_rt_acct __percpu *ip_rt_acct;
 108
 109struct in_device;
 110extern int              ip_rt_init(void);
 111extern void             rt_cache_flush(struct net *net);
 112extern void             rt_flush_dev(struct net_device *dev);
 113extern struct rtable *__ip_route_output_key(struct net *, struct flowi4 *flp);
 114extern struct rtable *ip_route_output_flow(struct net *, struct flowi4 *flp,
 115                                           struct sock *sk);
 116extern struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig);
 117
 118static inline struct rtable *ip_route_output_key(struct net *net, struct flowi4 *flp)
 119{
 120        return ip_route_output_flow(net, flp, NULL);
 121}
 122
 123static inline struct rtable *ip_route_output(struct net *net, __be32 daddr,
 124                                             __be32 saddr, u8 tos, int oif)
 125{
 126        struct flowi4 fl4 = {
 127                .flowi4_oif = oif,
 128                .flowi4_tos = tos,
 129                .daddr = daddr,
 130                .saddr = saddr,
 131        };
 132        return ip_route_output_key(net, &fl4);
 133}
 134
 135static inline struct rtable *ip_route_output_ports(struct net *net, struct flowi4 *fl4,
 136                                                   struct sock *sk,
 137                                                   __be32 daddr, __be32 saddr,
 138                                                   __be16 dport, __be16 sport,
 139                                                   __u8 proto, __u8 tos, int oif)
 140{
 141        flowi4_init_output(fl4, oif, sk ? sk->sk_mark : 0, tos,
 142                           RT_SCOPE_UNIVERSE, proto,
 143                           sk ? inet_sk_flowi_flags(sk) : 0,
 144                           daddr, saddr, dport, sport);
 145        if (sk)
 146                security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
 147        return ip_route_output_flow(net, fl4, sk);
 148}
 149
 150static inline struct rtable *ip_route_output_gre(struct net *net, struct flowi4 *fl4,
 151                                                 __be32 daddr, __be32 saddr,
 152                                                 __be32 gre_key, __u8 tos, int oif)
 153{
 154        memset(fl4, 0, sizeof(*fl4));
 155        fl4->flowi4_oif = oif;
 156        fl4->daddr = daddr;
 157        fl4->saddr = saddr;
 158        fl4->flowi4_tos = tos;
 159        fl4->flowi4_proto = IPPROTO_GRE;
 160        fl4->fl4_gre_key = gre_key;
 161        return ip_route_output_key(net, fl4);
 162}
 163
 164extern int ip_route_input_noref(struct sk_buff *skb, __be32 dst, __be32 src,
 165                                u8 tos, struct net_device *devin);
 166
 167static inline int ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src,
 168                                 u8 tos, struct net_device *devin)
 169{
 170        int err;
 171
 172        rcu_read_lock();
 173        err = ip_route_input_noref(skb, dst, src, tos, devin);
 174        if (!err)
 175                skb_dst_force(skb);
 176        rcu_read_unlock();
 177
 178        return err;
 179}
 180
 181extern void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
 182                             int oif, u32 mark, u8 protocol, int flow_flags);
 183extern void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu);
 184extern void ipv4_redirect(struct sk_buff *skb, struct net *net,
 185                          int oif, u32 mark, u8 protocol, int flow_flags);
 186extern void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk);
 187extern void ip_rt_send_redirect(struct sk_buff *skb);
 188
 189extern unsigned int             inet_addr_type(struct net *net, __be32 addr);
 190extern unsigned int             inet_dev_addr_type(struct net *net, const struct net_device *dev, __be32 addr);
 191extern void             ip_rt_multicast_event(struct in_device *);
 192extern int              ip_rt_ioctl(struct net *, unsigned int cmd, void __user *arg);
 193extern void             ip_rt_get_source(u8 *src, struct sk_buff *skb, struct rtable *rt);
 194extern int              ip_rt_dump(struct sk_buff *skb,  struct netlink_callback *cb);
 195
 196struct in_ifaddr;
 197extern void fib_add_ifaddr(struct in_ifaddr *);
 198extern void fib_del_ifaddr(struct in_ifaddr *, struct in_ifaddr *);
 199
 200static inline void ip_rt_put(struct rtable * rt)
 201{
 202        if (rt)
 203                dst_release(&rt->dst);
 204}
 205
 206#define IPTOS_RT_MASK   (IPTOS_TOS_MASK & ~3)
 207
 208extern const __u8 ip_tos2prio[16];
 209
 210static inline char rt_tos2priority(u8 tos)
 211{
 212        return ip_tos2prio[IPTOS_TOS(tos)>>1];
 213}
 214
 215/* ip_route_connect() and ip_route_newports() work in tandem whilst
 216 * binding a socket for a new outgoing connection.
 217 *
 218 * In order to use IPSEC properly, we must, in the end, have a
 219 * route that was looked up using all available keys including source
 220 * and destination ports.
 221 *
 222 * However, if a source port needs to be allocated (the user specified
 223 * a wildcard source port) we need to obtain addressing information
 224 * in order to perform that allocation.
 225 *
 226 * So ip_route_connect() looks up a route using wildcarded source and
 227 * destination ports in the key, simply so that we can get a pair of
 228 * addresses to use for port allocation.
 229 *
 230 * Later, once the ports are allocated, ip_route_newports() will make
 231 * another route lookup if needed to make sure we catch any IPSEC
 232 * rules keyed on the port information.
 233 *
 234 * The callers allocate the flow key on their stack, and must pass in
 235 * the same flowi4 object to both the ip_route_connect() and the
 236 * ip_route_newports() calls.
 237 */
 238
 239static inline void ip_route_connect_init(struct flowi4 *fl4, __be32 dst, __be32 src,
 240                                         u32 tos, int oif, u8 protocol,
 241                                         __be16 sport, __be16 dport,
 242                                         struct sock *sk, bool can_sleep)
 243{
 244        __u8 flow_flags = 0;
 245
 246        if (inet_sk(sk)->transparent)
 247                flow_flags |= FLOWI_FLAG_ANYSRC;
 248        if (can_sleep)
 249                flow_flags |= FLOWI_FLAG_CAN_SLEEP;
 250
 251        flowi4_init_output(fl4, oif, sk->sk_mark, tos, RT_SCOPE_UNIVERSE,
 252                           protocol, flow_flags, dst, src, dport, sport);
 253}
 254
 255static inline struct rtable *ip_route_connect(struct flowi4 *fl4,
 256                                              __be32 dst, __be32 src, u32 tos,
 257                                              int oif, u8 protocol,
 258                                              __be16 sport, __be16 dport,
 259                                              struct sock *sk, bool can_sleep)
 260{
 261        struct net *net = sock_net(sk);
 262        struct rtable *rt;
 263
 264        ip_route_connect_init(fl4, dst, src, tos, oif, protocol,
 265                              sport, dport, sk, can_sleep);
 266
 267        if (!dst || !src) {
 268                rt = __ip_route_output_key(net, fl4);
 269                if (IS_ERR(rt))
 270                        return rt;
 271                ip_rt_put(rt);
 272                flowi4_update_output(fl4, oif, tos, fl4->daddr, fl4->saddr);
 273        }
 274        security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
 275        return ip_route_output_flow(net, fl4, sk);
 276}
 277
 278static inline struct rtable *ip_route_newports(struct flowi4 *fl4, struct rtable *rt,
 279                                               __be16 orig_sport, __be16 orig_dport,
 280                                               __be16 sport, __be16 dport,
 281                                               struct sock *sk)
 282{
 283        if (sport != orig_sport || dport != orig_dport) {
 284                fl4->fl4_dport = dport;
 285                fl4->fl4_sport = sport;
 286                ip_rt_put(rt);
 287                flowi4_update_output(fl4, sk->sk_bound_dev_if,
 288                                     RT_CONN_FLAGS(sk), fl4->daddr,
 289                                     fl4->saddr);
 290                security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
 291                return ip_route_output_flow(sock_net(sk), fl4, sk);
 292        }
 293        return rt;
 294}
 295
 296static inline int inet_iif(const struct sk_buff *skb)
 297{
 298        int iif = skb_rtable(skb)->rt_iif;
 299
 300        if (iif)
 301                return iif;
 302        return skb->skb_iif;
 303}
 304
 305extern int sysctl_ip_default_ttl;
 306
 307static inline int ip4_dst_hoplimit(const struct dst_entry *dst)
 308{
 309        int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
 310
 311        if (hoplimit == 0)
 312                hoplimit = sysctl_ip_default_ttl;
 313        return hoplimit;
 314}
 315
 316#endif  /* _ROUTE_H */
 317
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