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/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
  43 struct fib_nh;
  44 struct fib_info;
  45 struct 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
  62 static inline bool rt_is_input_route(const struct rtable *rt)
  63 {
  64         return rt->rt_is_input != 0;
  65 }
  66
  67 static inline bool rt_is_output_route(const struct rtable *rt)
  68 {
  69         return rt->rt_is_input == 0;
  70 }
  71
  72 static inline __be32 rt_nexthop(const struct rtable *rt, __be32 daddr)
  73 {
  74         if (rt->rt_gateway)
  75                 return rt->rt_gateway;
  76         return daddr;
  77 }
  78
  79 struct ip_rt_acct {
  80         __u32   o_bytes;
  81         __u32   o_packets;
  82         __u32   i_bytes;
  83         __u32   i_packets;
  84 };
  85
  86 struct rt_cache_stat {
  87         unsigned int in_hit;
  88         unsigned int in_slow_tot;
  89         unsigned int in_slow_mc;
  90         unsigned int in_no_route;
  91         unsigned int in_brd;
  92         unsigned int in_martian_dst;
  93         unsigned int in_martian_src;
  94         unsigned int out_hit;
  95         unsigned int out_slow_tot;
  96         unsigned int out_slow_mc;
  97         unsigned int gc_total;
  98         unsigned int gc_ignored;
  99         unsigned int gc_goal_miss;
 100         unsigned int gc_dst_overflow;
 101         unsigned int in_hlist_search;
 102         unsigned int out_hlist_search;
 103 };
 104
 105 extern struct ip_rt_acct __percpu *ip_rt_acct;
 106
 107 struct in_device;
 108 extern int              ip_rt_init(void);
 109 extern void             rt_cache_flush(struct net *net, int how);
 110 extern struct rtable *__ip_route_output_key(struct net *, struct flowi4 *flp);
 111 extern struct rtable *ip_route_output_flow(struct net *, struct flowi4 *flp,
 112                                            struct sock *sk);
 113 extern struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig);
 114
 115 static inline struct rtable *ip_route_output_key(struct net *net, struct flowi4 *flp)
 116 {
 117         return ip_route_output_flow(net, flp, NULL);
 118 }
 119
 120 static inline struct rtable *ip_route_output(struct net *net, __be32 daddr,
 121                                              __be32 saddr, u8 tos, int oif)
 122 {
 123         struct flowi4 fl4 = {
 124                 .flowi4_oif = oif,
 125                 .flowi4_tos = tos,
 126                 .daddr = daddr,
 127                 .saddr = saddr,
 128         };
 129         return ip_route_output_key(net, &fl4);
 130 }
 131
 132 static inline struct rtable *ip_route_output_ports(struct net *net, struct flowi4 *fl4,
 133                                                    struct sock *sk,
 134                                                    __be32 daddr, __be32 saddr,
 135                                                    __be16 dport, __be16 sport,
 136                                                    __u8 proto, __u8 tos, int oif)
 137 {
 138         flowi4_init_output(fl4, oif, sk ? sk->sk_mark : 0, tos,
 139                            RT_SCOPE_UNIVERSE, proto,
 140                            sk ? inet_sk_flowi_flags(sk) : 0,
 141                            daddr, saddr, dport, sport);
 142         if (sk)
 143                 security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
 144         return ip_route_output_flow(net, fl4, sk);
 145 }
 146
 147 static inline struct rtable *ip_route_output_gre(struct net *net, struct flowi4 *fl4,
 148                                                  __be32 daddr, __be32 saddr,
 149                                                  __be32 gre_key, __u8 tos, int oif)
 150 {
 151         memset(fl4, 0, sizeof(*fl4));
 152         fl4->flowi4_oif = oif;
 153         fl4->daddr = daddr;
 154         fl4->saddr = saddr;
 155         fl4->flowi4_tos = tos;
 156         fl4->flowi4_proto = IPPROTO_GRE;
 157         fl4->fl4_gre_key = gre_key;
 158         return ip_route_output_key(net, fl4);
 159 }
 160
 161 extern int ip_route_input_noref(struct sk_buff *skb, __be32 dst, __be32 src,
 162                                 u8 tos, struct net_device *devin);
 163
 164 static inline int ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src,
 165                                  u8 tos, struct net_device *devin)
 166 {
 167         int err;
 168
 169         rcu_read_lock();
 170         err = ip_route_input_noref(skb, dst, src, tos, devin);
 171         if (!err)
 172                 skb_dst_force(skb);
 173         rcu_read_unlock();
 174
 175         return err;
 176 }
 177
 178 extern void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
 179                              int oif, u32 mark, u8 protocol, int flow_flags);
 180 extern void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu);
 181 extern void ipv4_redirect(struct sk_buff *skb, struct net *net,
 182                           int oif, u32 mark, u8 protocol, int flow_flags);
 183 extern void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk);
 184 extern void ip_rt_send_redirect(struct sk_buff *skb);
 185
 186 extern unsigned int             inet_addr_type(struct net *net, __be32 addr);
 187 extern unsigned int             inet_dev_addr_type(struct net *net, const struct net_device *dev, __be32 addr);
 188 extern void             ip_rt_multicast_event(struct in_device *);
 189 extern int              ip_rt_ioctl(struct net *, unsigned int cmd, void __user *arg);
 190 extern void             ip_rt_get_source(u8 *src, struct sk_buff *skb, struct rtable *rt);
 191 extern int              ip_rt_dump(struct sk_buff *skb,  struct netlink_callback *cb);
 192
 193 struct in_ifaddr;
 194 extern void fib_add_ifaddr(struct in_ifaddr *);
 195 extern void fib_del_ifaddr(struct in_ifaddr *, struct in_ifaddr *);
 196
 197 static inline void ip_rt_put(struct rtable * rt)
 198 {
 199         if (rt)
 200                 dst_release(&rt->dst);
 201 }
 202
 203 #define IPTOS_RT_MASK   (IPTOS_TOS_MASK & ~3)
 204
 205 extern const __u8 ip_tos2prio[16];
 206
 207 static inline char rt_tos2priority(u8 tos)
 208 {
 209         return ip_tos2prio[IPTOS_TOS(tos)>>1];
 210 }
 211
 212 /* ip_route_connect() and ip_route_newports() work in tandem whilst
 213  * binding a socket for a new outgoing connection.
 214  *
 215  * In order to use IPSEC properly, we must, in the end, have a
 216  * route that was looked up using all available keys including source
 217  * and destination ports.
 218  *
 219  * However, if a source port needs to be allocated (the user specified
 220  * a wildcard source port) we need to obtain addressing information
 221  * in order to perform that allocation.
 222  *
 223  * So ip_route_connect() looks up a route using wildcarded source and
 224  * destination ports in the key, simply so that we can get a pair of
 225  * addresses to use for port allocation.
 226  *
 227  * Later, once the ports are allocated, ip_route_newports() will make
 228  * another route lookup if needed to make sure we catch any IPSEC
 229  * rules keyed on the port information.
 230  *
 231  * The callers allocate the flow key on their stack, and must pass in
 232  * the same flowi4 object to both the ip_route_connect() and the
 233  * ip_route_newports() calls.
 234  */
 235
 236 static inline void ip_route_connect_init(struct flowi4 *fl4, __be32 dst, __be32 src,
 237                                          u32 tos, int oif, u8 protocol,
 238                                          __be16 sport, __be16 dport,
 239                                          struct sock *sk, bool can_sleep)
 240 {
 241         __u8 flow_flags = 0;
 242
 243         if (inet_sk(sk)->transparent)
 244                 flow_flags |= FLOWI_FLAG_ANYSRC;
 245         if (can_sleep)
 246                 flow_flags |= FLOWI_FLAG_CAN_SLEEP;
 247
 248         flowi4_init_output(fl4, oif, sk->sk_mark, tos, RT_SCOPE_UNIVERSE,
 249                            protocol, flow_flags, dst, src, dport, sport);
 250 }
 251
 252 static inline struct rtable *ip_route_connect(struct flowi4 *fl4,
 253                                               __be32 dst, __be32 src, u32 tos,
 254                                               int oif, u8 protocol,
 255                                               __be16 sport, __be16 dport,
 256                                               struct sock *sk, bool can_sleep)
 257 {
 258         struct net *net = sock_net(sk);
 259         struct rtable *rt;
 260
 261         ip_route_connect_init(fl4, dst, src, tos, oif, protocol,
 262                               sport, dport, sk, can_sleep);
 263
 264         if (!dst || !src) {
 265                 rt = __ip_route_output_key(net, fl4);
 266                 if (IS_ERR(rt))
 267                         return rt;
 268                 ip_rt_put(rt);
 269                 flowi4_update_output(fl4, oif, tos, fl4->daddr, fl4->saddr);
 270         }
 271         security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
 272         return ip_route_output_flow(net, fl4, sk);
 273 }
 274
 275 static inline struct rtable *ip_route_newports(struct flowi4 *fl4, struct rtable *rt,
 276                                                __be16 orig_sport, __be16 orig_dport,
 277                                                __be16 sport, __be16 dport,
 278                                                struct sock *sk)
 279 {
 280         if (sport != orig_sport || dport != orig_dport) {
 281                 fl4->fl4_dport = dport;
 282                 fl4->fl4_sport = sport;
 283                 ip_rt_put(rt);
 284                 flowi4_update_output(fl4, sk->sk_bound_dev_if,
 285                                      RT_CONN_FLAGS(sk), fl4->daddr,
 286                                      fl4->saddr);
 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 static inline int inet_iif(const struct sk_buff *skb)
 294 {
 295         int iif = skb_rtable(skb)->rt_iif;
 296
 297         if (iif)
 298                 return iif;
 299         return skb->skb_iif;
 300 }
 301
 302 extern int sysctl_ip_default_ttl;
 303
 304 static inline int ip4_dst_hoplimit(const struct dst_entry *dst)
 305 {
 306         int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
 307
 308         if (hoplimit == 0)
 309                 hoplimit = sysctl_ip_default_ttl;
 310         return hoplimit;
 311 }
 312
 313 #endif  /* _ROUTE_H */