include/net/ip6_route.h

0001 /* SPDX-License-Identifier: GPL-2.0 */
0002 #ifndef _NET_IP6_ROUTE_H
0003 #define _NET_IP6_ROUTE_H
0004
0005 #include <net/addrconf.h>
0006 #include <net/flow.h>
0007 #include <net/ip6_fib.h>
0008 #include <net/sock.h>
0009 #include <net/lwtunnel.h>
0010 #include <linux/ip.h>
0011 #include <linux/ipv6.h>
0012 #include <linux/route.h>
0013 #include <net/nexthop.h>
0014
0015 struct route_info {
0016     __u8            type;
0017     __u8            length;
0018     __u8            prefix_len;
0019 #if defined(__BIG_ENDIAN_BITFIELD)
0020     __u8            reserved_h:3,
0021                 route_pref:2,
0022                 reserved_l:3;
0023 #elif defined(__LITTLE_ENDIAN_BITFIELD)
0024     __u8            reserved_l:3,
0025                 route_pref:2,
0026                 reserved_h:3;
0027 #endif
0028     __be32          lifetime;
0029     __u8            prefix[];   /* 0,8 or 16 */
0030 };
0031
0032 #define RT6_LOOKUP_F_IFACE      0x00000001
0033 #define RT6_LOOKUP_F_REACHABLE      0x00000002
0034 #define RT6_LOOKUP_F_HAS_SADDR      0x00000004
0035 #define RT6_LOOKUP_F_SRCPREF_TMP    0x00000008
0036 #define RT6_LOOKUP_F_SRCPREF_PUBLIC 0x00000010
0037 #define RT6_LOOKUP_F_SRCPREF_COA    0x00000020
0038 #define RT6_LOOKUP_F_IGNORE_LINKSTATE   0x00000040
0039 #define RT6_LOOKUP_F_DST_NOREF      0x00000080
0040
0041 /* We do not (yet ?) support IPv6 jumbograms (RFC 2675)
0042  * Unlike IPv4, hdr->seg_len doesn't include the IPv6 header
0043  */
0044 #define IP6_MAX_MTU (0xFFFF + sizeof(struct ipv6hdr))
0045
0046 /*
0047  * rt6_srcprefs2flags() and rt6_flags2srcprefs() translate
0048  * between IPV6_ADDR_PREFERENCES socket option values
0049  *  IPV6_PREFER_SRC_TMP    = 0x1
0050  *  IPV6_PREFER_SRC_PUBLIC = 0x2
0051  *  IPV6_PREFER_SRC_COA    = 0x4
0052  * and above RT6_LOOKUP_F_SRCPREF_xxx flags.
0053  */
0054 static inline int rt6_srcprefs2flags(unsigned int srcprefs)
0055 {
0056     /* No need to bitmask because srcprefs have only 3 bits. */
0057     return srcprefs << 3;
0058 }
0059
0060 static inline unsigned int rt6_flags2srcprefs(int flags)
0061 {
0062     return (flags >> 3) & 7;
0063 }
0064
0065 static inline bool rt6_need_strict(const struct in6_addr *daddr)
0066 {
0067     return ipv6_addr_type(daddr) &
0068         (IPV6_ADDR_MULTICAST | IPV6_ADDR_LINKLOCAL | IPV6_ADDR_LOOPBACK);
0069 }
0070
0071 /* fib entries using a nexthop object can not be coalesced into
0072  * a multipath route
0073  */
0074 static inline bool rt6_qualify_for_ecmp(const struct fib6_info *f6i)
0075 {
0076     /* the RTF_ADDRCONF flag filters out RA's */
0077     return !(f6i->fib6_flags & RTF_ADDRCONF) && !f6i->nh &&
0078         f6i->fib6_nh->fib_nh_gw_family;
0079 }
0080
0081 void ip6_route_input(struct sk_buff *skb);
0082 struct dst_entry *ip6_route_input_lookup(struct net *net,
0083                      struct net_device *dev,
0084                      struct flowi6 *fl6,
0085                      const struct sk_buff *skb, int flags);
0086
0087 struct dst_entry *ip6_route_output_flags_noref(struct net *net,
0088                            const struct sock *sk,
0089                            struct flowi6 *fl6, int flags);
0090
0091 struct dst_entry *ip6_route_output_flags(struct net *net, const struct sock *sk,
0092                      struct flowi6 *fl6, int flags);
0093
0094 static inline struct dst_entry *ip6_route_output(struct net *net,
0095                          const struct sock *sk,
0096                          struct flowi6 *fl6)
0097 {
0098     return ip6_route_output_flags(net, sk, fl6, 0);
0099 }
0100
0101 /* Only conditionally release dst if flags indicates
0102  * !RT6_LOOKUP_F_DST_NOREF or dst is in uncached_list.
0103  */
0104 static inline void ip6_rt_put_flags(struct rt6_info *rt, int flags)
0105 {
0106     if (!(flags & RT6_LOOKUP_F_DST_NOREF) ||
0107         !list_empty(&rt->rt6i_uncached))
0108         ip6_rt_put(rt);
0109 }
0110
0111 struct dst_entry *ip6_route_lookup(struct net *net, struct flowi6 *fl6,
0112                    const struct sk_buff *skb, int flags);
0113 struct rt6_info *ip6_pol_route(struct net *net, struct fib6_table *table,
0114                    int ifindex, struct flowi6 *fl6,
0115                    const struct sk_buff *skb, int flags);
0116
0117 void ip6_route_init_special_entries(void);
0118 int ip6_route_init(void);
0119 void ip6_route_cleanup(void);
0120
0121 int ipv6_route_ioctl(struct net *net, unsigned int cmd,
0122         struct in6_rtmsg *rtmsg);
0123
0124 int ip6_route_add(struct fib6_config *cfg, gfp_t gfp_flags,
0125           struct netlink_ext_ack *extack);
0126 int ip6_ins_rt(struct net *net, struct fib6_info *f6i);
0127 int ip6_del_rt(struct net *net, struct fib6_info *f6i, bool skip_notify);
0128
0129 void rt6_flush_exceptions(struct fib6_info *f6i);
0130 void rt6_age_exceptions(struct fib6_info *f6i, struct fib6_gc_args *gc_args,
0131             unsigned long now);
0132
0133 static inline int ip6_route_get_saddr(struct net *net, struct fib6_info *f6i,
0134                       const struct in6_addr *daddr,
0135                       unsigned int prefs,
0136                       struct in6_addr *saddr)
0137 {
0138     int err = 0;
0139
0140     if (f6i && f6i->fib6_prefsrc.plen) {
0141         *saddr = f6i->fib6_prefsrc.addr;
0142     } else {
0143         struct net_device *dev = f6i ? fib6_info_nh_dev(f6i) : NULL;
0144
0145         err = ipv6_dev_get_saddr(net, dev, daddr, prefs, saddr);
0146     }
0147
0148     return err;
0149 }
0150
0151 struct rt6_info *rt6_lookup(struct net *net, const struct in6_addr *daddr,
0152                 const struct in6_addr *saddr, int oif,
0153                 const struct sk_buff *skb, int flags);
0154 u32 rt6_multipath_hash(const struct net *net, const struct flowi6 *fl6,
0155                const struct sk_buff *skb, struct flow_keys *hkeys);
0156
0157 struct dst_entry *icmp6_dst_alloc(struct net_device *dev, struct flowi6 *fl6);
0158
0159 void fib6_force_start_gc(struct net *net);
0160
0161 struct fib6_info *addrconf_f6i_alloc(struct net *net, struct inet6_dev *idev,
0162                      const struct in6_addr *addr, bool anycast,
0163                      gfp_t gfp_flags);
0164
0165 struct rt6_info *ip6_dst_alloc(struct net *net, struct net_device *dev,
0166                    int flags);
0167
0168 /*
0169  *  support functions for ND
0170  *
0171  */
0172 struct fib6_info *rt6_get_dflt_router(struct net *net,
0173                      const struct in6_addr *addr,
0174                      struct net_device *dev);
0175 struct fib6_info *rt6_add_dflt_router(struct net *net,
0176                      const struct in6_addr *gwaddr,
0177                      struct net_device *dev, unsigned int pref,
0178                      u32 defrtr_usr_metric);
0179
0180 void rt6_purge_dflt_routers(struct net *net);
0181
0182 int rt6_route_rcv(struct net_device *dev, u8 *opt, int len,
0183           const struct in6_addr *gwaddr);
0184
0185 void ip6_update_pmtu(struct sk_buff *skb, struct net *net, __be32 mtu, int oif,
0186              u32 mark, kuid_t uid);
0187 void ip6_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, __be32 mtu);
0188 void ip6_redirect(struct sk_buff *skb, struct net *net, int oif, u32 mark,
0189           kuid_t uid);
0190 void ip6_redirect_no_header(struct sk_buff *skb, struct net *net, int oif);
0191 void ip6_sk_redirect(struct sk_buff *skb, struct sock *sk);
0192
0193 struct netlink_callback;
0194
0195 struct rt6_rtnl_dump_arg {
0196     struct sk_buff *skb;
0197     struct netlink_callback *cb;
0198     struct net *net;
0199     struct fib_dump_filter filter;
0200 };
0201
0202 int rt6_dump_route(struct fib6_info *f6i, void *p_arg, unsigned int skip);
0203 void rt6_mtu_change(struct net_device *dev, unsigned int mtu);
0204 void rt6_remove_prefsrc(struct inet6_ifaddr *ifp);
0205 void rt6_clean_tohost(struct net *net, struct in6_addr *gateway);
0206 void rt6_sync_up(struct net_device *dev, unsigned char nh_flags);
0207 void rt6_disable_ip(struct net_device *dev, unsigned long event);
0208 void rt6_sync_down_dev(struct net_device *dev, unsigned long event);
0209 void rt6_multipath_rebalance(struct fib6_info *f6i);
0210
0211 void rt6_uncached_list_add(struct rt6_info *rt);
0212 void rt6_uncached_list_del(struct rt6_info *rt);
0213
0214 static inline const struct rt6_info *skb_rt6_info(const struct sk_buff *skb)
0215 {
0216     const struct dst_entry *dst = skb_dst(skb);
0217     const struct rt6_info *rt6 = NULL;
0218
0219     if (dst)
0220         rt6 = container_of(dst, struct rt6_info, dst);
0221
0222     return rt6;
0223 }
0224
0225 /*
0226  *  Store a destination cache entry in a socket
0227  */
0228 static inline void ip6_dst_store(struct sock *sk, struct dst_entry *dst,
0229                  const struct in6_addr *daddr,
0230                  const struct in6_addr *saddr)
0231 {
0232     struct ipv6_pinfo *np = inet6_sk(sk);
0233
0234     np->dst_cookie = rt6_get_cookie((struct rt6_info *)dst);
0235     sk_setup_caps(sk, dst);
0236     np->daddr_cache = daddr;
0237 #ifdef CONFIG_IPV6_SUBTREES
0238     np->saddr_cache = saddr;
0239 #endif
0240 }
0241
0242 void ip6_sk_dst_store_flow(struct sock *sk, struct dst_entry *dst,
0243                const struct flowi6 *fl6);
0244
0245 static inline bool ipv6_unicast_destination(const struct sk_buff *skb)
0246 {
0247     struct rt6_info *rt = (struct rt6_info *) skb_dst(skb);
0248
0249     return rt->rt6i_flags & RTF_LOCAL;
0250 }
0251
0252 static inline bool ipv6_anycast_destination(const struct dst_entry *dst,
0253                         const struct in6_addr *daddr)
0254 {
0255     struct rt6_info *rt = (struct rt6_info *)dst;
0256
0257     return rt->rt6i_flags & RTF_ANYCAST ||
0258         (rt->rt6i_dst.plen < 127 &&
0259          !(rt->rt6i_flags & (RTF_GATEWAY | RTF_NONEXTHOP)) &&
0260          ipv6_addr_equal(&rt->rt6i_dst.addr, daddr));
0261 }
0262
0263 int ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
0264          int (*output)(struct net *, struct sock *, struct sk_buff *));
0265
0266 static inline unsigned int ip6_skb_dst_mtu(const struct sk_buff *skb)
0267 {
0268     const struct ipv6_pinfo *np = skb->sk && !dev_recursion_level() ?
0269                 inet6_sk(skb->sk) : NULL;
0270     const struct dst_entry *dst = skb_dst(skb);
0271     unsigned int mtu;
0272
0273     if (np && np->pmtudisc >= IPV6_PMTUDISC_PROBE) {
0274         mtu = READ_ONCE(dst->dev->mtu);
0275         mtu -= lwtunnel_headroom(dst->lwtstate, mtu);
0276     } else {
0277         mtu = dst_mtu(dst);
0278     }
0279     return mtu;
0280 }
0281
0282 static inline bool ip6_sk_accept_pmtu(const struct sock *sk)
0283 {
0284     return inet6_sk(sk)->pmtudisc != IPV6_PMTUDISC_INTERFACE &&
0285            inet6_sk(sk)->pmtudisc != IPV6_PMTUDISC_OMIT;
0286 }
0287
0288 static inline bool ip6_sk_ignore_df(const struct sock *sk)
0289 {
0290     return inet6_sk(sk)->pmtudisc < IPV6_PMTUDISC_DO ||
0291            inet6_sk(sk)->pmtudisc == IPV6_PMTUDISC_OMIT;
0292 }
0293
0294 static inline const struct in6_addr *rt6_nexthop(const struct rt6_info *rt,
0295                          const struct in6_addr *daddr)
0296 {
0297     if (rt->rt6i_flags & RTF_GATEWAY)
0298         return &rt->rt6i_gateway;
0299     else if (unlikely(rt->rt6i_flags & RTF_CACHE))
0300         return &rt->rt6i_dst.addr;
0301     else
0302         return daddr;
0303 }
0304
0305 static inline bool rt6_duplicate_nexthop(struct fib6_info *a, struct fib6_info *b)
0306 {
0307     struct fib6_nh *nha, *nhb;
0308
0309     if (a->nh || b->nh)
0310         return nexthop_cmp(a->nh, b->nh);
0311
0312     nha = a->fib6_nh;
0313     nhb = b->fib6_nh;
0314     return nha->fib_nh_dev == nhb->fib_nh_dev &&
0315            ipv6_addr_equal(&nha->fib_nh_gw6, &nhb->fib_nh_gw6) &&
0316            !lwtunnel_cmp_encap(nha->fib_nh_lws, nhb->fib_nh_lws);
0317 }
0318
0319 static inline unsigned int ip6_dst_mtu_maybe_forward(const struct dst_entry *dst,
0320                              bool forwarding)
0321 {
0322     struct inet6_dev *idev;
0323     unsigned int mtu;
0324
0325     if (!forwarding || dst_metric_locked(dst, RTAX_MTU)) {
0326         mtu = dst_metric_raw(dst, RTAX_MTU);
0327         if (mtu)
0328             goto out;
0329     }
0330
0331     mtu = IPV6_MIN_MTU;
0332     rcu_read_lock();
0333     idev = __in6_dev_get(dst->dev);
0334     if (idev)
0335         mtu = idev->cnf.mtu6;
0336     rcu_read_unlock();
0337
0338 out:
0339     return mtu - lwtunnel_headroom(dst->lwtstate, mtu);
0340 }
0341
0342 u32 ip6_mtu_from_fib6(const struct fib6_result *res,
0343               const struct in6_addr *daddr,
0344               const struct in6_addr *saddr);
0345
0346 struct neighbour *ip6_neigh_lookup(const struct in6_addr *gw,
0347                    struct net_device *dev, struct sk_buff *skb,
0348                    const void *daddr);
0349 #endif