/* * lwtunnel Infrastructure for light weight tunnels like mpls * * Authors: Roopa Prabhu, <roopa@cumulusnetworks.com> * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. * */ #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/nexthop.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_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(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(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(lwtunnel_encap_del_ops); int lwtunnel_build_state(struct net_device *dev, u16 encap_type, struct nlattr *encap, unsigned int family, const void *cfg, struct lwtunnel_state **lws) { const struct lwtunnel_encap_ops *ops; int ret = -EINVAL; if (encap_type == LWTUNNEL_ENCAP_NONE || encap_type > LWTUNNEL_ENCAP_MAX) 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))) { ret = ops->build_state(dev, encap, family, cfg, lws); if (ret) module_put(ops->owner); } rcu_read_unlock(); return ret; } EXPORT_SYMBOL(lwtunnel_build_state); int lwtunnel_valid_encap_type(u16 encap_type) { const struct lwtunnel_encap_ops *ops; int ret = -EINVAL; if (encap_type == LWTUNNEL_ENCAP_NONE || encap_type > LWTUNNEL_ENCAP_MAX) 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 return ops ? 0 : -EOPNOTSUPP; } EXPORT_SYMBOL(lwtunnel_valid_encap_type); int lwtunnel_valid_encap_type_attr(struct nlattr *attr, int remaining) { struct rtnexthop *rtnh = (struct rtnexthop *)attr; struct nlattr *nla_entype; struct nlattr *attrs; struct nlattr *nla; u16 encap_type; int attrlen; while (rtnh_ok(rtnh, remaining)) { attrlen = rtnh_attrlen(rtnh); if (attrlen > 0) { attrs = rtnh_attrs(rtnh); nla = nla_find(attrs, attrlen, RTA_ENCAP); nla_entype = nla_find(attrs, attrlen, RTA_ENCAP_TYPE); if (nla_entype) { encap_type = nla_get_u16(nla_entype); if (lwtunnel_valid_encap_type(encap_type) != 0) return -EOPNOTSUPP; } } rtnh = rtnh_next(rtnh, &remaining); } return 0; } EXPORT_SYMBOL(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(lwtstate_free); int lwtunnel_fill_encap(struct sk_buff *skb, struct lwtunnel_state *lwtstate) { const struct lwtunnel_encap_ops *ops; struct nlattr *nest; int ret = -EINVAL; if (!lwtstate) return 0; if (lwtstate->type == LWTUNNEL_ENCAP_NONE || lwtstate->type > LWTUNNEL_ENCAP_MAX) return 0; ret = -EOPNOTSUPP; nest = nla_nest_start(skb, RTA_ENCAP); 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, RTA_ENCAP_TYPE, 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(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(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(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(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(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(lwtunnel_input);