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_mtu_locked:1,
  67                                 rt_pmtu:31;
  68
  69         struct list_head        rt_uncached;
  70         struct uncached_list    *rt_uncached_list;
  71 };
  72
  73 static inline bool rt_is_input_route(const struct rtable *rt)
  74 {
  75         return rt->rt_is_input != 0;
  76 }
  77
  78 static inline bool rt_is_output_route(const struct rtable *rt)
  79 {
  80         return rt->rt_is_input == 0;
  81 }
  82
  83 static inline __be32 rt_nexthop(const struct rtable *rt, __be32 daddr)
  84 {
  85         if (rt->rt_gateway)
  86                 return rt->rt_gateway;
  87         return daddr;
  88 }
  89
  90 struct ip_rt_acct {
  91         __u32   o_bytes;
  92         __u32   o_packets;
  93         __u32   i_bytes;
  94         __u32   i_packets;
  95 };
  96
  97 struct rt_cache_stat {
  98         unsigned int in_slow_tot;
  99         unsigned int in_slow_mc;
 100         unsigned int in_no_route;
 101         unsigned int in_brd;
 102         unsigned int in_martian_dst;
 103         unsigned int in_martian_src;
 104         unsigned int out_slow_tot;
 105         unsigned int out_slow_mc;
 106 };
 107
 108 extern struct ip_rt_acct __percpu *ip_rt_acct;
 109
 110 struct in_device;
 111
 112 int ip_rt_init(void);
 113 void rt_cache_flush(struct net *net);
 114 void rt_flush_dev(struct net_device *dev);
 115 struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *flp,
 116                                         const struct sk_buff *skb);
 117 struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *flp,
 118                                             struct fib_result *res,
 119                                             const struct sk_buff *skb);
 120
 121 static inline struct rtable *__ip_route_output_key(struct net *net,
 122                                                    struct flowi4 *flp)
 123 {
 124         return ip_route_output_key_hash(net, flp, NULL);
 125 }
 126
 127 struct rtable *ip_route_output_flow(struct net *, struct flowi4 *flp,
 128                                     const struct sock *sk);
 129 struct dst_entry *ipv4_blackhole_route(struct net *net,
 130                                        struct dst_entry *dst_orig);
 131
 132 static inline struct rtable *ip_route_output_key(struct net *net, struct flowi4 *flp)
 133 {
 134         return ip_route_output_flow(net, flp, NULL);
 135 }
 136
 137 static inline struct rtable *ip_route_output(struct net *net, __be32 daddr,
 138                                              __be32 saddr, u8 tos, int oif)
 139 {
 140         struct flowi4 fl4 = {
 141                 .flowi4_oif = oif,
 142                 .flowi4_tos = tos,
 143                 .daddr = daddr,
 144                 .saddr = saddr,
 145         };
 146         return ip_route_output_key(net, &fl4);
 147 }
 148
 149 static inline struct rtable *ip_route_output_ports(struct net *net, struct flowi4 *fl4,
 150                                                    struct sock *sk,
 151                                                    __be32 daddr, __be32 saddr,
 152                                                    __be16 dport, __be16 sport,
 153                                                    __u8 proto, __u8 tos, int oif)
 154 {
 155         flowi4_init_output(fl4, oif, sk ? sk->sk_mark : 0, tos,
 156                            RT_SCOPE_UNIVERSE, proto,
 157                            sk ? inet_sk_flowi_flags(sk) : 0,
 158                            daddr, saddr, dport, sport, sock_net_uid(net, sk));
 159         if (sk)
 160                 security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
 161         return ip_route_output_flow(net, fl4, sk);
 162 }
 163
 164 static inline struct rtable *ip_route_output_gre(struct net *net, struct flowi4 *fl4,
 165                                                  __be32 daddr, __be32 saddr,
 166                                                  __be32 gre_key, __u8 tos, int oif)
 167 {
 168         memset(fl4, 0, sizeof(*fl4));
 169         fl4->flowi4_oif = oif;
 170         fl4->daddr = daddr;
 171         fl4->saddr = saddr;
 172         fl4->flowi4_tos = tos;
 173         fl4->flowi4_proto = IPPROTO_GRE;
 174         fl4->fl4_gre_key = gre_key;
 175         return ip_route_output_key(net, fl4);
 176 }
 177 int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 178                           u8 tos, struct net_device *dev,
 179                           struct in_device *in_dev, u32 *itag);
 180 int ip_route_input_noref(struct sk_buff *skb, __be32 dst, __be32 src,
 181                          u8 tos, struct net_device *devin);
 182 int ip_route_input_rcu(struct sk_buff *skb, __be32 dst, __be32 src,
 183                        u8 tos, struct net_device *devin,
 184                        struct fib_result *res);
 185
 186 static inline int ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src,
 187                                  u8 tos, struct net_device *devin)
 188 {
 189         int err;
 190
 191         rcu_read_lock();
 192         err = ip_route_input_noref(skb, dst, src, tos, devin);
 193         if (!err) {
 194                 skb_dst_force(skb);
 195                 if (!skb_dst(skb))
 196                         err = -EINVAL;
 197         }
 198         rcu_read_unlock();
 199
 200         return err;
 201 }
 202
 203 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, int oif,
 204                       u8 protocol);
 205 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu);
 206 void ipv4_redirect(struct sk_buff *skb, struct net *net, int oif, u8 protocol);
 207 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk);
 208 void ip_rt_send_redirect(struct sk_buff *skb);
 209
 210 unsigned int inet_addr_type(struct net *net, __be32 addr);
 211 unsigned int inet_addr_type_table(struct net *net, __be32 addr, u32 tb_id);
 212 unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev,
 213                                 __be32 addr);
 214 unsigned int inet_addr_type_dev_table(struct net *net,
 215                                       const struct net_device *dev,
 216                                       __be32 addr);
 217 void ip_rt_multicast_event(struct in_device *);
 218 int ip_rt_ioctl(struct net *, unsigned int cmd, struct rtentry *rt);
 219 void ip_rt_get_source(u8 *src, struct sk_buff *skb, struct rtable *rt);
 220 struct rtable *rt_dst_alloc(struct net_device *dev,
 221                              unsigned int flags, u16 type,
 222                              bool nopolicy, bool noxfrm, bool will_cache);
 223
 224 struct in_ifaddr;
 225 void fib_add_ifaddr(struct in_ifaddr *);
 226 void fib_del_ifaddr(struct in_ifaddr *, struct in_ifaddr *);
 227 void fib_modify_prefix_metric(struct in_ifaddr *ifa, u32 new_metric);
 228
 229 void rt_add_uncached_list(struct rtable *rt);
 230 void rt_del_uncached_list(struct rtable *rt);
 231
 232 static inline void ip_rt_put(struct rtable *rt)
 233 {
 234         /* dst_release() accepts a NULL parameter.
 235          * We rely on dst being first structure in struct rtable
 236          */
 237         BUILD_BUG_ON(offsetof(struct rtable, dst) != 0);
 238         dst_release(&rt->dst);
 239 }
 240
 241 #define IPTOS_RT_MASK   (IPTOS_TOS_MASK & ~3)
 242
 243 extern const __u8 ip_tos2prio[16];
 244
 245 static inline char rt_tos2priority(u8 tos)
 246 {
 247         return ip_tos2prio[IPTOS_TOS(tos)>>1];
 248 }
 249
 250 /* ip_route_connect() and ip_route_newports() work in tandem whilst
 251  * binding a socket for a new outgoing connection.
 252  *
 253  * In order to use IPSEC properly, we must, in the end, have a
 254  * route that was looked up using all available keys including source
 255  * and destination ports.
 256  *
 257  * However, if a source port needs to be allocated (the user specified
 258  * a wildcard source port) we need to obtain addressing information
 259  * in order to perform that allocation.
 260  *
 261  * So ip_route_connect() looks up a route using wildcarded source and
 262  * destination ports in the key, simply so that we can get a pair of
 263  * addresses to use for port allocation.
 264  *
 265  * Later, once the ports are allocated, ip_route_newports() will make
 266  * another route lookup if needed to make sure we catch any IPSEC
 267  * rules keyed on the port information.
 268  *
 269  * The callers allocate the flow key on their stack, and must pass in
 270  * the same flowi4 object to both the ip_route_connect() and the
 271  * ip_route_newports() calls.
 272  */
 273
 274 static inline void ip_route_connect_init(struct flowi4 *fl4, __be32 dst, __be32 src,
 275                                          u32 tos, int oif, u8 protocol,
 276                                          __be16 sport, __be16 dport,
 277                                          struct sock *sk)
 278 {
 279         __u8 flow_flags = 0;
 280
 281         if (inet_sk(sk)->transparent)
 282                 flow_flags |= FLOWI_FLAG_ANYSRC;
 283
 284         flowi4_init_output(fl4, oif, sk->sk_mark, tos, RT_SCOPE_UNIVERSE,
 285                            protocol, flow_flags, dst, src, dport, sport,
 286                            sk->sk_uid);
 287 }
 288
 289 static inline struct rtable *ip_route_connect(struct flowi4 *fl4,
 290                                               __be32 dst, __be32 src, u32 tos,
 291                                               int oif, u8 protocol,
 292                                               __be16 sport, __be16 dport,
 293                                               struct sock *sk)
 294 {
 295         struct net *net = sock_net(sk);
 296         struct rtable *rt;
 297
 298         ip_route_connect_init(fl4, dst, src, tos, oif, protocol,
 299                               sport, dport, sk);
 300
 301         if (!dst || !src) {
 302                 rt = __ip_route_output_key(net, fl4);
 303                 if (IS_ERR(rt))
 304                         return rt;
 305                 ip_rt_put(rt);
 306                 flowi4_update_output(fl4, oif, tos, fl4->daddr, fl4->saddr);
 307         }
 308         security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
 309         return ip_route_output_flow(net, fl4, sk);
 310 }
 311
 312 static inline struct rtable *ip_route_newports(struct flowi4 *fl4, struct rtable *rt,
 313                                                __be16 orig_sport, __be16 orig_dport,
 314                                                __be16 sport, __be16 dport,
 315                                                struct sock *sk)
 316 {
 317         if (sport != orig_sport || dport != orig_dport) {
 318                 fl4->fl4_dport = dport;
 319                 fl4->fl4_sport = sport;
 320                 ip_rt_put(rt);
 321                 flowi4_update_output(fl4, sk->sk_bound_dev_if,
 322                                      RT_CONN_FLAGS(sk), fl4->daddr,
 323                                      fl4->saddr);
 324                 security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
 325                 return ip_route_output_flow(sock_net(sk), fl4, sk);
 326         }
 327         return rt;
 328 }
 329
 330 static inline int inet_iif(const struct sk_buff *skb)
 331 {
 332         struct rtable *rt = skb_rtable(skb);
 333
 334         if (rt && rt->rt_iif)
 335                 return rt->rt_iif;
 336
 337         return skb->skb_iif;
 338 }
 339
 340 static inline int ip4_dst_hoplimit(const struct dst_entry *dst)
 341 {
 342         int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
 343         struct net *net = dev_net(dst->dev);
 344
 345         if (hoplimit == 0)
 346                 hoplimit = net->ipv4.sysctl_ip_default_ttl;
 347         return hoplimit;
 348 }
 349
 350 #endif  /* _ROUTE_H */