diff options
Diffstat (limited to 'include/net/nexthop.h')
| -rw-r--r-- | include/net/nexthop.h | 307 |
1 files changed, 307 insertions, 0 deletions
diff --git a/include/net/nexthop.h b/include/net/nexthop.h new file mode 100644 index 000000000000..331ebbc94fe7 --- /dev/null +++ b/include/net/nexthop.h @@ -0,0 +1,307 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Generic nexthop implementation + * + * Copyright (c) 2017-19 Cumulus Networks + * Copyright (c) 2017-19 David Ahern <dsa@cumulusnetworks.com> + */ + +#ifndef __LINUX_NEXTHOP_H +#define __LINUX_NEXTHOP_H + +#include <linux/netdevice.h> +#include <linux/route.h> +#include <linux/types.h> +#include <net/ip_fib.h> +#include <net/ip6_fib.h> +#include <net/netlink.h> + +#define NEXTHOP_VALID_USER_FLAGS RTNH_F_ONLINK + +struct nexthop; + +struct nh_config { + u32 nh_id; + + u8 nh_family; + u8 nh_protocol; + u8 nh_blackhole; + u32 nh_flags; + + int nh_ifindex; + struct net_device *dev; + + union { + __be32 ipv4; + struct in6_addr ipv6; + } gw; + + struct nlattr *nh_grp; + u16 nh_grp_type; + + struct nlattr *nh_encap; + u16 nh_encap_type; + + u32 nlflags; + struct nl_info nlinfo; +}; + +struct nh_info { + struct hlist_node dev_hash; /* entry on netns devhash */ + struct nexthop *nh_parent; + + u8 family; + bool reject_nh; + + union { + struct fib_nh_common fib_nhc; + struct fib_nh fib_nh; + struct fib6_nh fib6_nh; + }; +}; + +struct nh_grp_entry { + struct nexthop *nh; + u8 weight; + atomic_t upper_bound; + + struct list_head nh_list; + struct nexthop *nh_parent; /* nexthop of group with this entry */ +}; + +struct nh_group { + u16 num_nh; + bool mpath; + bool has_v4; + struct nh_grp_entry nh_entries[0]; +}; + +struct nexthop { + struct rb_node rb_node; /* entry on netns rbtree */ + struct list_head fi_list; /* v4 entries using nh */ + struct list_head f6i_list; /* v6 entries using nh */ + struct list_head grp_list; /* nh group entries using this nh */ + struct net *net; + + u32 id; + + u8 protocol; /* app managing this nh */ + u8 nh_flags; + bool is_group; + + refcount_t refcnt; + struct rcu_head rcu; + + union { + struct nh_info __rcu *nh_info; + struct nh_group __rcu *nh_grp; + }; +}; + +/* caller is holding rcu or rtnl; no reference taken to nexthop */ +struct nexthop *nexthop_find_by_id(struct net *net, u32 id); +void nexthop_free_rcu(struct rcu_head *head); + +static inline bool nexthop_get(struct nexthop *nh) +{ + return refcount_inc_not_zero(&nh->refcnt); +} + +static inline void nexthop_put(struct nexthop *nh) +{ + if (refcount_dec_and_test(&nh->refcnt)) + call_rcu(&nh->rcu, nexthop_free_rcu); +} + +static inline bool nexthop_cmp(const struct nexthop *nh1, + const struct nexthop *nh2) +{ + return nh1 == nh2; +} + +static inline bool nexthop_is_multipath(const struct nexthop *nh) +{ + if (nh->is_group) { + struct nh_group *nh_grp; + + nh_grp = rcu_dereference_rtnl(nh->nh_grp); + return nh_grp->mpath; + } + return false; +} + +struct nexthop *nexthop_select_path(struct nexthop *nh, int hash); + +static inline unsigned int nexthop_num_path(const struct nexthop *nh) +{ + unsigned int rc = 1; + + if (nexthop_is_multipath(nh)) { + struct nh_group *nh_grp; + + nh_grp = rcu_dereference_rtnl(nh->nh_grp); + rc = nh_grp->num_nh; + } + + return rc; +} + +static inline +struct nexthop *nexthop_mpath_select(const struct nexthop *nh, int nhsel) +{ + const struct nh_group *nhg = rcu_dereference_rtnl(nh->nh_grp); + + /* for_nexthops macros in fib_semantics.c grabs a pointer to + * the nexthop before checking nhsel + */ + if (nhsel >= nhg->num_nh) + return NULL; + + return nhg->nh_entries[nhsel].nh; +} + +static inline +int nexthop_mpath_fill_node(struct sk_buff *skb, struct nexthop *nh, + u8 rt_family) +{ + struct nh_group *nhg = rtnl_dereference(nh->nh_grp); + int i; + + for (i = 0; i < nhg->num_nh; i++) { + struct nexthop *nhe = nhg->nh_entries[i].nh; + struct nh_info *nhi = rcu_dereference_rtnl(nhe->nh_info); + struct fib_nh_common *nhc = &nhi->fib_nhc; + int weight = nhg->nh_entries[i].weight; + + if (fib_add_nexthop(skb, nhc, weight, rt_family) < 0) + return -EMSGSIZE; + } + + return 0; +} + +/* called with rcu lock */ +static inline bool nexthop_is_blackhole(const struct nexthop *nh) +{ + const struct nh_info *nhi; + + if (nexthop_is_multipath(nh)) { + if (nexthop_num_path(nh) > 1) + return false; + nh = nexthop_mpath_select(nh, 0); + if (!nh) + return false; + } + + nhi = rcu_dereference_rtnl(nh->nh_info); + return nhi->reject_nh; +} + +static inline void nexthop_path_fib_result(struct fib_result *res, int hash) +{ + struct nh_info *nhi; + struct nexthop *nh; + + nh = nexthop_select_path(res->fi->nh, hash); + nhi = rcu_dereference(nh->nh_info); + res->nhc = &nhi->fib_nhc; +} + +/* called with rcu read lock or rtnl held */ +static inline +struct fib_nh_common *nexthop_fib_nhc(struct nexthop *nh, int nhsel) +{ + struct nh_info *nhi; + + BUILD_BUG_ON(offsetof(struct fib_nh, nh_common) != 0); + BUILD_BUG_ON(offsetof(struct fib6_nh, nh_common) != 0); + + if (nexthop_is_multipath(nh)) { + nh = nexthop_mpath_select(nh, nhsel); + if (!nh) + return NULL; + } + + nhi = rcu_dereference_rtnl(nh->nh_info); + return &nhi->fib_nhc; +} + +static inline unsigned int fib_info_num_path(const struct fib_info *fi) +{ + if (unlikely(fi->nh)) + return nexthop_num_path(fi->nh); + + return fi->fib_nhs; +} + +int fib_check_nexthop(struct nexthop *nh, u8 scope, + struct netlink_ext_ack *extack); + +static inline struct fib_nh_common *fib_info_nhc(struct fib_info *fi, int nhsel) +{ + if (unlikely(fi->nh)) + return nexthop_fib_nhc(fi->nh, nhsel); + + return &fi->fib_nh[nhsel].nh_common; +} + +/* only used when fib_nh is built into fib_info */ +static inline struct fib_nh *fib_info_nh(struct fib_info *fi, int nhsel) +{ + WARN_ON(fi->nh); + + return &fi->fib_nh[nhsel]; +} + +/* + * IPv6 variants + */ +int fib6_check_nexthop(struct nexthop *nh, struct fib6_config *cfg, + struct netlink_ext_ack *extack); + +static inline struct fib6_nh *nexthop_fib6_nh(struct nexthop *nh) +{ + struct nh_info *nhi; + + if (nexthop_is_multipath(nh)) { + nh = nexthop_mpath_select(nh, 0); + if (!nh) + return NULL; + } + + nhi = rcu_dereference_rtnl(nh->nh_info); + if (nhi->family == AF_INET6) + return &nhi->fib6_nh; + + return NULL; +} + +static inline struct net_device *fib6_info_nh_dev(struct fib6_info *f6i) +{ + struct fib6_nh *fib6_nh; + + fib6_nh = f6i->nh ? nexthop_fib6_nh(f6i->nh) : f6i->fib6_nh; + return fib6_nh->fib_nh_dev; +} + +static inline void nexthop_path_fib6_result(struct fib6_result *res, int hash) +{ + struct nexthop *nh = res->f6i->nh; + struct nh_info *nhi; + + nh = nexthop_select_path(nh, hash); + + nhi = rcu_dereference_rtnl(nh->nh_info); + if (nhi->reject_nh) { + res->fib6_type = RTN_BLACKHOLE; + res->fib6_flags |= RTF_REJECT; + res->nh = nexthop_fib6_nh(nh); + } else { + res->nh = &nhi->fib6_nh; + } +} + +int nexthop_for_each_fib6_nh(struct nexthop *nh, + int (*cb)(struct fib6_nh *nh, void *arg), + void *arg); +#endif |