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