diff options
Diffstat (limited to 'net/core/lwtunnel.c')
| -rw-r--r-- | net/core/lwtunnel.c | 419 |
1 files changed, 419 insertions, 0 deletions
diff --git a/net/core/lwtunnel.c b/net/core/lwtunnel.c new file mode 100644 index 000000000..f590b0e67 --- /dev/null +++ b/net/core/lwtunnel.c @@ -0,0 +1,419 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * lwtunnel Infrastructure for light weight tunnels like mpls + * + * Authors: Roopa Prabhu, <roopa@cumulusnetworks.com> + */ + +#include <linux/capability.h> +#include <linux/module.h> +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/slab.h> +#include <linux/uaccess.h> +#include <linux/skbuff.h> +#include <linux/netdevice.h> +#include <linux/lwtunnel.h> +#include <linux/in.h> +#include <linux/init.h> +#include <linux/err.h> + +#include <net/lwtunnel.h> +#include <net/rtnetlink.h> +#include <net/ip6_fib.h> +#include <net/rtnh.h> + +#ifdef CONFIG_MODULES + +static const char *lwtunnel_encap_str(enum lwtunnel_encap_types encap_type) +{ + /* Only lwt encaps implemented without using an interface for + * the encap need to return a string here. + */ + switch (encap_type) { + case LWTUNNEL_ENCAP_MPLS: + return "MPLS"; + case LWTUNNEL_ENCAP_ILA: + return "ILA"; + case LWTUNNEL_ENCAP_SEG6: + return "SEG6"; + case LWTUNNEL_ENCAP_BPF: + return "BPF"; + case LWTUNNEL_ENCAP_SEG6_LOCAL: + return "SEG6LOCAL"; + case LWTUNNEL_ENCAP_RPL: + return "RPL"; + case LWTUNNEL_ENCAP_IP6: + case LWTUNNEL_ENCAP_IP: + case LWTUNNEL_ENCAP_NONE: + case __LWTUNNEL_ENCAP_MAX: + /* should not have got here */ + WARN_ON(1); + break; + } + return NULL; +} + +#endif /* CONFIG_MODULES */ + +struct lwtunnel_state *lwtunnel_state_alloc(int encap_len) +{ + struct lwtunnel_state *lws; + + lws = kzalloc(sizeof(*lws) + encap_len, GFP_ATOMIC); + + return lws; +} +EXPORT_SYMBOL_GPL(lwtunnel_state_alloc); + +static const struct lwtunnel_encap_ops __rcu * + lwtun_encaps[LWTUNNEL_ENCAP_MAX + 1] __read_mostly; + +int lwtunnel_encap_add_ops(const struct lwtunnel_encap_ops *ops, + unsigned int num) +{ + if (num > LWTUNNEL_ENCAP_MAX) + return -ERANGE; + + return !cmpxchg((const struct lwtunnel_encap_ops **) + &lwtun_encaps[num], + NULL, ops) ? 0 : -1; +} +EXPORT_SYMBOL_GPL(lwtunnel_encap_add_ops); + +int lwtunnel_encap_del_ops(const struct lwtunnel_encap_ops *ops, + unsigned int encap_type) +{ + int ret; + + if (encap_type == LWTUNNEL_ENCAP_NONE || + encap_type > LWTUNNEL_ENCAP_MAX) + return -ERANGE; + + ret = (cmpxchg((const struct lwtunnel_encap_ops **) + &lwtun_encaps[encap_type], + ops, NULL) == ops) ? 0 : -1; + + synchronize_net(); + + return ret; +} +EXPORT_SYMBOL_GPL(lwtunnel_encap_del_ops); + +int lwtunnel_build_state(struct net *net, u16 encap_type, + struct nlattr *encap, unsigned int family, + const void *cfg, struct lwtunnel_state **lws, + struct netlink_ext_ack *extack) +{ + const struct lwtunnel_encap_ops *ops; + bool found = false; + int ret = -EINVAL; + + if (encap_type == LWTUNNEL_ENCAP_NONE || + encap_type > LWTUNNEL_ENCAP_MAX) { + NL_SET_ERR_MSG_ATTR(extack, encap, + "Unknown LWT encapsulation type"); + return ret; + } + + ret = -EOPNOTSUPP; + rcu_read_lock(); + ops = rcu_dereference(lwtun_encaps[encap_type]); + if (likely(ops && ops->build_state && try_module_get(ops->owner))) + found = true; + rcu_read_unlock(); + + if (found) { + ret = ops->build_state(net, encap, family, cfg, lws, extack); + if (ret) + module_put(ops->owner); + } else { + /* don't rely on -EOPNOTSUPP to detect match as build_state + * handlers could return it + */ + NL_SET_ERR_MSG_ATTR(extack, encap, + "LWT encapsulation type not supported"); + } + + return ret; +} +EXPORT_SYMBOL_GPL(lwtunnel_build_state); + +int lwtunnel_valid_encap_type(u16 encap_type, struct netlink_ext_ack *extack) +{ + const struct lwtunnel_encap_ops *ops; + int ret = -EINVAL; + + if (encap_type == LWTUNNEL_ENCAP_NONE || + encap_type > LWTUNNEL_ENCAP_MAX) { + NL_SET_ERR_MSG(extack, "Unknown lwt encapsulation type"); + return ret; + } + + rcu_read_lock(); + ops = rcu_dereference(lwtun_encaps[encap_type]); + rcu_read_unlock(); +#ifdef CONFIG_MODULES + if (!ops) { + const char *encap_type_str = lwtunnel_encap_str(encap_type); + + if (encap_type_str) { + __rtnl_unlock(); + request_module("rtnl-lwt-%s", encap_type_str); + rtnl_lock(); + + rcu_read_lock(); + ops = rcu_dereference(lwtun_encaps[encap_type]); + rcu_read_unlock(); + } + } +#endif + ret = ops ? 0 : -EOPNOTSUPP; + if (ret < 0) + NL_SET_ERR_MSG(extack, "lwt encapsulation type not supported"); + + return ret; +} +EXPORT_SYMBOL_GPL(lwtunnel_valid_encap_type); + +int lwtunnel_valid_encap_type_attr(struct nlattr *attr, int remaining, + struct netlink_ext_ack *extack) +{ + struct rtnexthop *rtnh = (struct rtnexthop *)attr; + struct nlattr *nla_entype; + struct nlattr *attrs; + u16 encap_type; + int attrlen; + + while (rtnh_ok(rtnh, remaining)) { + attrlen = rtnh_attrlen(rtnh); + if (attrlen > 0) { + attrs = rtnh_attrs(rtnh); + nla_entype = nla_find(attrs, attrlen, RTA_ENCAP_TYPE); + + if (nla_entype) { + if (nla_len(nla_entype) < sizeof(u16)) { + NL_SET_ERR_MSG(extack, "Invalid RTA_ENCAP_TYPE"); + return -EINVAL; + } + encap_type = nla_get_u16(nla_entype); + + if (lwtunnel_valid_encap_type(encap_type, + extack) != 0) + return -EOPNOTSUPP; + } + } + rtnh = rtnh_next(rtnh, &remaining); + } + + return 0; +} +EXPORT_SYMBOL_GPL(lwtunnel_valid_encap_type_attr); + +void lwtstate_free(struct lwtunnel_state *lws) +{ + const struct lwtunnel_encap_ops *ops = lwtun_encaps[lws->type]; + + if (ops->destroy_state) { + ops->destroy_state(lws); + kfree_rcu(lws, rcu); + } else { + kfree(lws); + } + module_put(ops->owner); +} +EXPORT_SYMBOL_GPL(lwtstate_free); + +int lwtunnel_fill_encap(struct sk_buff *skb, struct lwtunnel_state *lwtstate, + int encap_attr, int encap_type_attr) +{ + const struct lwtunnel_encap_ops *ops; + struct nlattr *nest; + int ret; + + if (!lwtstate) + return 0; + + if (lwtstate->type == LWTUNNEL_ENCAP_NONE || + lwtstate->type > LWTUNNEL_ENCAP_MAX) + return 0; + + nest = nla_nest_start_noflag(skb, encap_attr); + if (!nest) + return -EMSGSIZE; + + ret = -EOPNOTSUPP; + rcu_read_lock(); + ops = rcu_dereference(lwtun_encaps[lwtstate->type]); + if (likely(ops && ops->fill_encap)) + ret = ops->fill_encap(skb, lwtstate); + rcu_read_unlock(); + + if (ret) + goto nla_put_failure; + nla_nest_end(skb, nest); + ret = nla_put_u16(skb, encap_type_attr, lwtstate->type); + if (ret) + goto nla_put_failure; + + return 0; + +nla_put_failure: + nla_nest_cancel(skb, nest); + + return (ret == -EOPNOTSUPP ? 0 : ret); +} +EXPORT_SYMBOL_GPL(lwtunnel_fill_encap); + +int lwtunnel_get_encap_size(struct lwtunnel_state *lwtstate) +{ + const struct lwtunnel_encap_ops *ops; + int ret = 0; + + if (!lwtstate) + return 0; + + if (lwtstate->type == LWTUNNEL_ENCAP_NONE || + lwtstate->type > LWTUNNEL_ENCAP_MAX) + return 0; + + rcu_read_lock(); + ops = rcu_dereference(lwtun_encaps[lwtstate->type]); + if (likely(ops && ops->get_encap_size)) + ret = nla_total_size(ops->get_encap_size(lwtstate)); + rcu_read_unlock(); + + return ret; +} +EXPORT_SYMBOL_GPL(lwtunnel_get_encap_size); + +int lwtunnel_cmp_encap(struct lwtunnel_state *a, struct lwtunnel_state *b) +{ + const struct lwtunnel_encap_ops *ops; + int ret = 0; + + if (!a && !b) + return 0; + + if (!a || !b) + return 1; + + if (a->type != b->type) + return 1; + + if (a->type == LWTUNNEL_ENCAP_NONE || + a->type > LWTUNNEL_ENCAP_MAX) + return 0; + + rcu_read_lock(); + ops = rcu_dereference(lwtun_encaps[a->type]); + if (likely(ops && ops->cmp_encap)) + ret = ops->cmp_encap(a, b); + rcu_read_unlock(); + + return ret; +} +EXPORT_SYMBOL_GPL(lwtunnel_cmp_encap); + +int lwtunnel_output(struct net *net, struct sock *sk, struct sk_buff *skb) +{ + struct dst_entry *dst = skb_dst(skb); + const struct lwtunnel_encap_ops *ops; + struct lwtunnel_state *lwtstate; + int ret = -EINVAL; + + if (!dst) + goto drop; + lwtstate = dst->lwtstate; + + if (lwtstate->type == LWTUNNEL_ENCAP_NONE || + lwtstate->type > LWTUNNEL_ENCAP_MAX) + return 0; + + ret = -EOPNOTSUPP; + rcu_read_lock(); + ops = rcu_dereference(lwtun_encaps[lwtstate->type]); + if (likely(ops && ops->output)) + ret = ops->output(net, sk, skb); + rcu_read_unlock(); + + if (ret == -EOPNOTSUPP) + goto drop; + + return ret; + +drop: + kfree_skb(skb); + + return ret; +} +EXPORT_SYMBOL_GPL(lwtunnel_output); + +int lwtunnel_xmit(struct sk_buff *skb) +{ + struct dst_entry *dst = skb_dst(skb); + const struct lwtunnel_encap_ops *ops; + struct lwtunnel_state *lwtstate; + int ret = -EINVAL; + + if (!dst) + goto drop; + + lwtstate = dst->lwtstate; + + if (lwtstate->type == LWTUNNEL_ENCAP_NONE || + lwtstate->type > LWTUNNEL_ENCAP_MAX) + return 0; + + ret = -EOPNOTSUPP; + rcu_read_lock(); + ops = rcu_dereference(lwtun_encaps[lwtstate->type]); + if (likely(ops && ops->xmit)) + ret = ops->xmit(skb); + rcu_read_unlock(); + + if (ret == -EOPNOTSUPP) + goto drop; + + return ret; + +drop: + kfree_skb(skb); + + return ret; +} +EXPORT_SYMBOL_GPL(lwtunnel_xmit); + +int lwtunnel_input(struct sk_buff *skb) +{ + struct dst_entry *dst = skb_dst(skb); + const struct lwtunnel_encap_ops *ops; + struct lwtunnel_state *lwtstate; + int ret = -EINVAL; + + if (!dst) + goto drop; + lwtstate = dst->lwtstate; + + if (lwtstate->type == LWTUNNEL_ENCAP_NONE || + lwtstate->type > LWTUNNEL_ENCAP_MAX) + return 0; + + ret = -EOPNOTSUPP; + rcu_read_lock(); + ops = rcu_dereference(lwtun_encaps[lwtstate->type]); + if (likely(ops && ops->input)) + ret = ops->input(skb); + rcu_read_unlock(); + + if (ret == -EOPNOTSUPP) + goto drop; + + return ret; + +drop: + kfree_skb(skb); + + return ret; +} +EXPORT_SYMBOL_GPL(lwtunnel_input); |