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 <linux/in_route.h>
  32 #include <linux/rtnetlink.h>
  33 #include <linux/route.h>
  34 #include <linux/ip.h>
  35 #include <linux/cache.h>
  36 #include <linux/security.h>
  37
  38 #define RTO_ONLINK      0x01
  39
  40 #define RT_CONN_FLAGS(sk)   (RT_TOS(inet_sk(sk)->tos) | sock_flag(sk, SOCK_LOCALROUTE))
  41
  42 struct fib_nh;
  43 struct inet_peer;
  44 struct fib_info;
  45 struct rtable {
  46         struct dst_entry        dst;
  47
  48         /* Lookup key. */
  49         __be32                  rt_key_dst;
  50         __be32                  rt_key_src;
  51
  52         int                     rt_genid;
  53         unsigned                rt_flags;
  54         __u16                   rt_type;
  55         __u8                    rt_key_tos;
  56
  57         __be32                  rt_dst; /* Path destination     */
  58         __be32                  rt_src; /* Path source          */
  59         int                     rt_route_iif;
  60         int                     rt_iif;
  61         int                     rt_oif;
  62         __u32                   rt_mark;
  63
  64         /* Info on neighbour */
  65         __be32                  rt_gateway;
  66
  67         /* Miscellaneous cached information */
  68         __be32                  rt_spec_dst; /* RFC1122 specific destination */
  69         u32                     rt_peer_genid;
  70         struct inet_peer        *peer; /* long-living peer info */
  71         struct fib_info         *fi; /* for client ref to shared metrics */
  72 };
  73
  74 static inline bool rt_is_input_route(const struct rtable *rt)
  75 {
  76         return rt->rt_route_iif != 0;
  77 }
  78
  79 static inline bool rt_is_output_route(const struct rtable *rt)
  80 {
  81         return rt->rt_route_iif == 0;
  82 }
  83
  84 struct ip_rt_acct {
  85         __u32   o_bytes;
  86         __u32   o_packets;
  87         __u32   i_bytes;
  88         __u32   i_packets;
  89 };
  90
  91 struct rt_cache_stat {
  92         unsigned int in_hit;
  93         unsigned int in_slow_tot;
  94         unsigned int in_slow_mc;
  95         unsigned int in_no_route;
  96         unsigned int in_brd;
  97         unsigned int in_martian_dst;
  98         unsigned int in_martian_src;
  99         unsigned int out_hit;
 100         unsigned int out_slow_tot;
 101         unsigned int out_slow_mc;
 102         unsigned int gc_total;
 103         unsigned int gc_ignored;
 104         unsigned int gc_goal_miss;
 105         unsigned int gc_dst_overflow;
 106         unsigned int in_hlist_search;
 107         unsigned int out_hlist_search;
 108 };
 109
 110 extern struct ip_rt_acct __percpu *ip_rt_acct;
 111
 112 struct in_device;
 113 extern int              ip_rt_init(void);
 114 extern void             ip_rt_redirect(__be32 old_gw, __be32 dst, __be32 new_gw,
 115                                        __be32 src, struct net_device *dev);
 116 extern void             rt_cache_flush(struct net *net, int how);
 117 extern void             rt_cache_flush_batch(struct net *net);
 118 extern struct rtable *__ip_route_output_key(struct net *, struct flowi4 *flp);
 119 extern struct rtable *ip_route_output_flow(struct net *, struct flowi4 *flp,
 120                                            struct sock *sk);
 121 extern struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig);
 122
 123 static inline struct rtable *ip_route_output_key(struct net *net, struct flowi4 *flp)
 124 {
 125         return ip_route_output_flow(net, flp, NULL);
 126 }
 127
 128 static inline struct rtable *ip_route_output(struct net *net, __be32 daddr,
 129                                              __be32 saddr, u8 tos, int oif)
 130 {
 131         struct flowi4 fl4 = {
 132                 .flowi4_oif = oif,
 133                 .daddr = daddr,
 134                 .saddr = saddr,
 135                 .flowi4_tos = tos,
 136         };
 137         return ip_route_output_key(net, &fl4);
 138 }
 139
 140 static inline struct rtable *ip_route_output_ports(struct net *net, struct flowi4 *fl4,
 141                                                    struct sock *sk,
 142                                                    __be32 daddr, __be32 saddr,
 143                                                    __be16 dport, __be16 sport,
 144                                                    __u8 proto, __u8 tos, int oif)
 145 {
 146         flowi4_init_output(fl4, oif, sk ? sk->sk_mark : 0, tos,
 147                            RT_SCOPE_UNIVERSE, proto,
 148                            sk ? inet_sk_flowi_flags(sk) : 0,
 149                            daddr, saddr, dport, sport);
 150         if (sk)
 151                 security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
 152         return ip_route_output_flow(net, fl4, sk);
 153 }
 154
 155 static inline struct rtable *ip_route_output_gre(struct net *net, struct flowi4 *fl4,
 156                                                  __be32 daddr, __be32 saddr,
 157                                                  __be32 gre_key, __u8 tos, int oif)
 158 {
 159         memset(fl4, 0, sizeof(*fl4));
 160         fl4->flowi4_oif = oif;
 161         fl4->daddr = daddr;
 162         fl4->saddr = saddr;
 163         fl4->flowi4_tos = tos;
 164         fl4->flowi4_proto = IPPROTO_GRE;
 165         fl4->fl4_gre_key = gre_key;
 166         return ip_route_output_key(net, fl4);
 167 }
 168
 169 extern int ip_route_input_common(struct sk_buff *skb, __be32 dst, __be32 src,
 170                                  u8 tos, struct net_device *devin, bool noref);
 171
 172 static inline int ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src,
 173                                  u8 tos, struct net_device *devin)
 174 {
 175         return ip_route_input_common(skb, dst, src, tos, devin, false);
 176 }
 177
 178 static inline int ip_route_input_noref(struct sk_buff *skb, __be32 dst, __be32 src,
 179                                        u8 tos, struct net_device *devin)
 180 {
 181         return ip_route_input_common(skb, dst, src, tos, devin, true);
 182 }
 183
 184 extern unsigned short   ip_rt_frag_needed(struct net *net, const struct iphdr *iph,
 185                                           unsigned short new_mtu, struct net_device *dev);
 186 extern void             ip_rt_send_redirect(struct sk_buff *skb);
 187
 188 extern unsigned         inet_addr_type(struct net *net, __be32 addr);
 189 extern unsigned         inet_dev_addr_type(struct net *net, const struct net_device *dev, __be32 addr);
 190 extern void             ip_rt_multicast_event(struct in_device *);
 191 extern int              ip_rt_ioctl(struct net *, unsigned int cmd, void __user *arg);
 192 extern void             ip_rt_get_source(u8 *src, struct sk_buff *skb, struct rtable *rt);
 193 extern int              ip_rt_dump(struct sk_buff *skb,  struct netlink_callback *cb);
 194
 195 struct in_ifaddr;
 196 extern void fib_add_ifaddr(struct in_ifaddr *);
 197 extern void fib_del_ifaddr(struct in_ifaddr *, struct in_ifaddr *);
 198
 199 static inline void ip_rt_put(struct rtable * rt)
 200 {
 201         if (rt)
 202                 dst_release(&rt->dst);
 203 }
 204
 205 #define IPTOS_RT_MASK   (IPTOS_TOS_MASK & ~3)
 206
 207 extern const __u8 ip_tos2prio[16];
 208
 209 static inline char rt_tos2priority(u8 tos)
 210 {
 211         return ip_tos2prio[IPTOS_TOS(tos)>>1];
 212 }
 213
 214 /* ip_route_connect() and ip_route_newports() work in tandem whilst
 215  * binding a socket for a new outgoing connection.
 216  *
 217  * In order to use IPSEC properly, we must, in the end, have a
 218  * route that was looked up using all available keys including source
 219  * and destination ports.
 220  *
 221  * However, if a source port needs to be allocated (the user specified
 222  * a wildcard source port) we need to obtain addressing information
 223  * in order to perform that allocation.
 224  *
 225  * So ip_route_connect() looks up a route using wildcarded source and
 226  * destination ports in the key, simply so that we can get a pair of
 227  * addresses to use for port allocation.
 228  *
 229  * Later, once the ports are allocated, ip_route_newports() will make
 230  * another route lookup if needed to make sure we catch any IPSEC
 231  * rules keyed on the port information.
 232  *
 233  * The callers allocate the flow key on their stack, and must pass in
 234  * the same flowi4 object to both the ip_route_connect() and the
 235  * ip_route_newports() calls.
 236  */
 237
 238 static inline void ip_route_connect_init(struct flowi4 *fl4, __be32 dst, __be32 src,
 239                                          u32 tos, int oif, u8 protocol,
 240                                          __be16 sport, __be16 dport,
 241                                          struct sock *sk, bool can_sleep)
 242 {
 243         __u8 flow_flags = 0;
 244
 245         if (inet_sk(sk)->transparent)
 246                 flow_flags |= FLOWI_FLAG_ANYSRC;
 247         if (protocol == IPPROTO_TCP)
 248                 flow_flags |= FLOWI_FLAG_PRECOW_METRICS;
 249         if (can_sleep)
 250                 flow_flags |= FLOWI_FLAG_CAN_SLEEP;
 251
 252         flowi4_init_output(fl4, oif, sk->sk_mark, tos, RT_SCOPE_UNIVERSE,
 253                            protocol, flow_flags, dst, src, dport, sport);
 254 }
 255
 256 static inline struct rtable *ip_route_connect(struct flowi4 *fl4,
 257                                               __be32 dst, __be32 src, u32 tos,
 258                                               int oif, u8 protocol,
 259                                               __be16 sport, __be16 dport,
 260                                               struct sock *sk, bool can_sleep)
 261 {
 262         struct net *net = sock_net(sk);
 263         struct rtable *rt;
 264
 265         ip_route_connect_init(fl4, dst, src, tos, oif, protocol,
 266                               sport, dport, sk, can_sleep);
 267
 268         if (!dst || !src) {
 269                 rt = __ip_route_output_key(net, fl4);
 270                 if (IS_ERR(rt))
 271                         return rt;
 272                 ip_rt_put(rt);
 273         }
 274         security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
 275         return ip_route_output_flow(net, fl4, sk);
 276 }
 277
 278 static 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                 security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
 288                 return ip_route_output_flow(sock_net(sk), fl4, sk);
 289         }
 290         return rt;
 291 }
 292
 293 extern void rt_bind_peer(struct rtable *rt, __be32 daddr, int create);
 294
 295 static inline struct inet_peer *rt_get_peer(struct rtable *rt, __be32 daddr)
 296 {
 297         if (rt->peer)
 298                 return rt->peer;
 299
 300         rt_bind_peer(rt, daddr, 0);
 301         return rt->peer;
 302 }
 303
 304 static inline int inet_iif(const struct sk_buff *skb)
 305 {
 306         return skb_rtable(skb)->rt_iif;
 307 }
 308
 309 extern int sysctl_ip_default_ttl;
 310
 311 static inline int ip4_dst_hoplimit(const struct dst_entry *dst)
 312 {
 313         int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
 314
 315         if (hoplimit == 0)
 316                 hoplimit = sysctl_ip_default_ttl;
 317         return hoplimit;
 318 }
 319
 320 #endif  /* _ROUTE_H */