include/net/route.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 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 <net/ip_fib.h>
  32 #include <linux/in_route.h>
  33 #include <linux/rtnetlink.h>
  34 #include <linux/rcupdate.h>
  35 #include <linux/route.h>
  36 #include <linux/ip.h>
  37 #include <linux/cache.h>
  38 #include <linux/security.h>
  39
  40 /* IPv4 datagram length is stored into 16bit field (tot_len) */
  41 #define IP_MAX_MTU      0xFFFFU
  42
  43 #define RTO_ONLINK      0x01
  44
  45 #define RT_CONN_FLAGS(sk)   (RT_TOS(inet_sk(sk)->tos) | sock_flag(sk, SOCK_LOCALROUTE))
  46 #define RT_CONN_FLAGS_TOS(sk,tos)   (RT_TOS(tos) | sock_flag(sk, SOCK_LOCALROUTE))
  47
  48 struct fib_nh;
  49 struct fib_info;
  50 struct uncached_list;
  51 struct rtable {
  52         struct dst_entry        dst;
  53
  54         int                     rt_genid;
  55         unsigned int            rt_flags;
  56         __u16                   rt_type;
  57         __u8                    rt_is_input;
  58         __u8                    rt_uses_gateway;
  59
  60         int                     rt_iif;
  61
  62         /* Info on neighbour */
  63         __be32                  rt_gateway;
  64
  65         /* Miscellaneous cached information */
  66         u32                     rt_pmtu;
  67
  68         u32                     rt_table_id;
  69
  70         struct list_head        rt_uncached;
  71         struct uncached_list    *rt_uncached_list;
  72 };
  73
  74 static inline bool rt_is_input_route(const struct rtable *rt)
  75 {
  76         return rt->rt_is_input != 0;
  77 }
  78
  79 static inline bool rt_is_output_route(const struct rtable *rt)
  80 {
  81         return rt->rt_is_input == 0;
  82 }
  83
  84 static inline __be32 rt_nexthop(const struct rtable *rt, __be32 daddr)
  85 {
  86         if (rt->rt_gateway)
  87                 return rt->rt_gateway;
  88         return daddr;
  89 }
  90
  91 struct ip_rt_acct {
  92         __u32   o_bytes;
  93         __u32   o_packets;
  94         __u32   i_bytes;
  95         __u32   i_packets;
  96 };
  97
  98 struct rt_cache_stat {
  99         unsigned int in_slow_tot;
 100         unsigned int in_slow_mc;
 101         unsigned int in_no_route;
 102         unsigned int in_brd;
 103         unsigned int in_martian_dst;
 104         unsigned int in_martian_src;
 105         unsigned int out_slow_tot;
 106         unsigned int out_slow_mc;
 107 };
 108
 109 extern struct ip_rt_acct __percpu *ip_rt_acct;
 110
 111 struct in_device;
 112
 113 int ip_rt_init(void);
 114 void rt_cache_flush(struct net *net);
 115 void rt_flush_dev(struct net_device *dev);
 116 struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *flp,
 117                                         const struct sk_buff *skb);
 118 struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *flp,
 119                                             struct fib_result *res,
 120                                             const struct sk_buff *skb);
 121
 122 static inline struct rtable *__ip_route_output_key(struct net *net,
 123                                                    struct flowi4 *flp)
 124 {
 125         return ip_route_output_key_hash(net, flp, NULL);
 126 }
 127
 128 struct rtable *ip_route_output_flow(struct net *, struct flowi4 *flp,
 129                                     const struct sock *sk);
 130 struct dst_entry *ipv4_blackhole_route(struct net *net,
 131                                        struct dst_entry *dst_orig);
 132
 133 static inline struct rtable *ip_route_output_key(struct net *net, struct flowi4 *flp)
 134 {
 135         return ip_route_output_flow(net, flp, NULL);
 136 }
 137
 138 static inline struct rtable *ip_route_output(struct net *net, __be32 daddr,
 139                                              __be32 saddr, u8 tos, int oif)
 140 {
 141         struct flowi4 fl4 = {
 142                 .flowi4_oif = oif,
 143                 .flowi4_tos = tos,
 144                 .daddr = daddr,
 145                 .saddr = saddr,
 146         };
 147         return ip_route_output_key(net, &fl4);
 148 }
 149
 150 static inline struct rtable *ip_route_output_ports(struct net *net, struct flowi4 *fl4,
 151                                                    struct sock *sk,
 152                                                    __be32 daddr, __be32 saddr,
 153                                                    __be16 dport, __be16 sport,
 154                                                    __u8 proto, __u8 tos, int oif)
 155 {
 156         flowi4_init_output(fl4, oif, sk ? sk->sk_mark : 0, tos,
 157                            RT_SCOPE_UNIVERSE, proto,
 158                            sk ? inet_sk_flowi_flags(sk) : 0,
 159                            daddr, saddr, dport, sport, sock_net_uid(net, sk));
 160         if (sk)
 161                 security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
 162         return ip_route_output_flow(net, fl4, sk);
 163 }
 164
 165 static inline struct rtable *ip_route_output_gre(struct net *net, struct flowi4 *fl4,
 166                                                  __be32 daddr, __be32 saddr,
 167                                                  __be32 gre_key, __u8 tos, int oif)
 168 {
 169         memset(fl4, 0, sizeof(*fl4));
 170         fl4->flowi4_oif = oif;
 171         fl4->daddr = daddr;
 172         fl4->saddr = saddr;
 173         fl4->flowi4_tos = tos;
 174         fl4->flowi4_proto = IPPROTO_GRE;
 175         fl4->fl4_gre_key = gre_key;
 176         return ip_route_output_key(net, fl4);
 177 }
 178
 179 int ip_route_input_noref(struct sk_buff *skb, __be32 dst, __be32 src,
 180                          u8 tos, struct net_device *devin);
 181 int ip_route_input_rcu(struct sk_buff *skb, __be32 dst, __be32 src,
 182                        u8 tos, struct net_device *devin,
 183                        struct fib_result *res);
 184
 185 static inline int ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src,
 186                                  u8 tos, struct net_device *devin)
 187 {
 188         int err;
 189
 190         rcu_read_lock();
 191         err = ip_route_input_noref(skb, dst, src, tos, devin);
 192         if (!err)
 193                 skb_dst_force_safe(skb);
 194         if (!skb_dst(skb))
 195                 err = -EINVAL;
 196         rcu_read_unlock();
 197
 198         return err;
 199 }
 200
 201 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, int oif,
 202                       u32 mark, u8 protocol, int flow_flags);
 203 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu);
 204 void ipv4_redirect(struct sk_buff *skb, struct net *net, int oif, u32 mark,
 205                    u8 protocol, int flow_flags);
 206 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk);
 207 void ip_rt_send_redirect(struct sk_buff *skb);
 208
 209 unsigned int inet_addr_type(struct net *net, __be32 addr);
 210 unsigned int inet_addr_type_table(struct net *net, __be32 addr, u32 tb_id);
 211 unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev,
 212                                 __be32 addr);
 213 unsigned int inet_addr_type_dev_table(struct net *net,
 214                                       const struct net_device *dev,
 215                                       __be32 addr);
 216 void ip_rt_multicast_event(struct in_device *);
 217 int ip_rt_ioctl(struct net *, unsigned int cmd, void __user *arg);
 218 void ip_rt_get_source(u8 *src, struct sk_buff *skb, struct rtable *rt);
 219 struct rtable *rt_dst_alloc(struct net_device *dev,
 220                              unsigned int flags, u16 type,
 221                              bool nopolicy, bool noxfrm, bool will_cache);
 222
 223 struct in_ifaddr;
 224 void fib_add_ifaddr(struct in_ifaddr *);
 225 void fib_del_ifaddr(struct in_ifaddr *, struct in_ifaddr *);
 226
 227 static inline void ip_rt_put(struct rtable *rt)
 228 {
 229         /* dst_release() accepts a NULL parameter.
 230          * We rely on dst being first structure in struct rtable
 231          */
 232         BUILD_BUG_ON(offsetof(struct rtable, dst) != 0);
 233         dst_release(&rt->dst);
 234 }
 235
 236 #define IPTOS_RT_MASK   (IPTOS_TOS_MASK & ~3)
 237
 238 extern const __u8 ip_tos2prio[16];
 239
 240 static inline char rt_tos2priority(u8 tos)
 241 {
 242         return ip_tos2prio[IPTOS_TOS(tos)>>1];
 243 }
 244
 245 /* ip_route_connect() and ip_route_newports() work in tandem whilst
 246  * binding a socket for a new outgoing connection.
 247  *
 248  * In order to use IPSEC properly, we must, in the end, have a
 249  * route that was looked up using all available keys including source
 250  * and destination ports.
 251  *
 252  * However, if a source port needs to be allocated (the user specified
 253  * a wildcard source port) we need to obtain addressing information
 254  * in order to perform that allocation.
 255  *
 256  * So ip_route_connect() looks up a route using wildcarded source and
 257  * destination ports in the key, simply so that we can get a pair of
 258  * addresses to use for port allocation.
 259  *
 260  * Later, once the ports are allocated, ip_route_newports() will make
 261  * another route lookup if needed to make sure we catch any IPSEC
 262  * rules keyed on the port information.
 263  *
 264  * The callers allocate the flow key on their stack, and must pass in
 265  * the same flowi4 object to both the ip_route_connect() and the
 266  * ip_route_newports() calls.
 267  */
 268
 269 static inline void ip_route_connect_init(struct flowi4 *fl4, __be32 dst, __be32 src,
 270                                          u32 tos, int oif, u8 protocol,
 271                                          __be16 sport, __be16 dport,
 272                                          struct sock *sk)
 273 {
 274         __u8 flow_flags = 0;
 275
 276         if (inet_sk(sk)->transparent)
 277                 flow_flags |= FLOWI_FLAG_ANYSRC;
 278
 279         flowi4_init_output(fl4, oif, sk->sk_mark, tos, RT_SCOPE_UNIVERSE,
 280                            protocol, flow_flags, dst, src, dport, sport,
 281                            sk->sk_uid);
 282 }
 283
 284 static inline struct rtable *ip_route_connect(struct flowi4 *fl4,
 285                                               __be32 dst, __be32 src, u32 tos,
 286                                               int oif, u8 protocol,
 287                                               __be16 sport, __be16 dport,
 288                                               struct sock *sk)
 289 {
 290         struct net *net = sock_net(sk);
 291         struct rtable *rt;
 292
 293         ip_route_connect_init(fl4, dst, src, tos, oif, protocol,
 294                               sport, dport, sk);
 295
 296         if (!dst || !src) {
 297                 rt = __ip_route_output_key(net, fl4);
 298                 if (IS_ERR(rt))
 299                         return rt;
 300                 ip_rt_put(rt);
 301                 flowi4_update_output(fl4, oif, tos, fl4->daddr, fl4->saddr);
 302         }
 303         security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
 304         return ip_route_output_flow(net, fl4, sk);
 305 }
 306
 307 static inline struct rtable *ip_route_newports(struct flowi4 *fl4, struct rtable *rt,
 308                                                __be16 orig_sport, __be16 orig_dport,
 309                                                __be16 sport, __be16 dport,
 310                                                struct sock *sk)
 311 {
 312         if (sport != orig_sport || dport != orig_dport) {
 313                 fl4->fl4_dport = dport;
 314                 fl4->fl4_sport = sport;
 315                 ip_rt_put(rt);
 316                 flowi4_update_output(fl4, sk->sk_bound_dev_if,
 317                                      RT_CONN_FLAGS(sk), fl4->daddr,
 318                                      fl4->saddr);
 319                 security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
 320                 return ip_route_output_flow(sock_net(sk), fl4, sk);
 321         }
 322         return rt;
 323 }
 324
 325 static inline int inet_iif(const struct sk_buff *skb)
 326 {
 327         struct rtable *rt = skb_rtable(skb);
 328
 329         if (rt && rt->rt_iif)
 330                 return rt->rt_iif;
 331
 332         return skb->skb_iif;
 333 }
 334
 335 static inline int ip4_dst_hoplimit(const struct dst_entry *dst)
 336 {
 337         int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
 338         struct net *net = dev_net(dst->dev);
 339
 340         if (hoplimit == 0)
 341                 hoplimit = net->ipv4.sysctl_ip_default_ttl;
 342         return hoplimit;
 343 }
 344
 345 #endif  /* _ROUTE_H */