net: remove duplicate includes

[mirror_ubuntu-bionic-kernel.git] / net / sched / cls_api.c

/*
 * net/sched/cls_api.c  Packet classifier API.
 *
 *              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.
 *
 * Authors:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
 *
 * Changes:
 *
 * Eduardo J. Blanco <ejbs@netlabs.com.uy> :990222: kmod support
 *
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/skbuff.h>
#include <linux/init.h>
#include <linux/kmod.h>
#include <linux/slab.h>
#include <net/net_namespace.h>
#include <net/sock.h>
#include <net/netlink.h>
#include <net/pkt_sched.h>
#include <net/pkt_cls.h>

/* The list of all installed classifier types */
static LIST_HEAD(tcf_proto_base);

/* Protects list of registered TC modules. It is pure SMP lock. */
static DEFINE_RWLOCK(cls_mod_lock);

/* Find classifier type by string name */

static const struct tcf_proto_ops *tcf_proto_lookup_ops(const char *kind)
{
        const struct tcf_proto_ops *t, *res = NULL;

        if (kind) {
                read_lock(&cls_mod_lock);
                list_for_each_entry(t, &tcf_proto_base, head) {
                        if (strcmp(kind, t->kind) == 0) {
                                if (try_module_get(t->owner))
                                        res = t;
                                break;
                        }
                }
                read_unlock(&cls_mod_lock);
        }
        return res;
}

/* Register(unregister) new classifier type */

int register_tcf_proto_ops(struct tcf_proto_ops *ops)
{
        struct tcf_proto_ops *t;
        int rc = -EEXIST;

        write_lock(&cls_mod_lock);
        list_for_each_entry(t, &tcf_proto_base, head)
                if (!strcmp(ops->kind, t->kind))
                        goto out;

        list_add_tail(&ops->head, &tcf_proto_base);
        rc = 0;
out:
        write_unlock(&cls_mod_lock);
        return rc;
}
EXPORT_SYMBOL(register_tcf_proto_ops);

static struct workqueue_struct *tc_filter_wq;

int unregister_tcf_proto_ops(struct tcf_proto_ops *ops)
{
        struct tcf_proto_ops *t;
        int rc = -ENOENT;

        /* Wait for outstanding call_rcu()s, if any, from a
         * tcf_proto_ops's destroy() handler.
         */
        rcu_barrier();
        flush_workqueue(tc_filter_wq);

        write_lock(&cls_mod_lock);
        list_for_each_entry(t, &tcf_proto_base, head) {
                if (t == ops) {
                        list_del(&t->head);
                        rc = 0;
                        break;
                }
        }
        write_unlock(&cls_mod_lock);
        return rc;
}
EXPORT_SYMBOL(unregister_tcf_proto_ops);

bool tcf_queue_work(struct work_struct *work)
{
        return queue_work(tc_filter_wq, work);
}
EXPORT_SYMBOL(tcf_queue_work);

/* Select new prio value from the range, managed by kernel. */

static inline u32 tcf_auto_prio(struct tcf_proto *tp)
{
        u32 first = TC_H_MAKE(0xC0000000U, 0U);

        if (tp)
                first = tp->prio - 1;

        return TC_H_MAJ(first);
}

static struct tcf_proto *tcf_proto_create(const char *kind, u32 protocol,
                                          u32 prio, u32 parent, struct Qdisc *q,
                                          struct tcf_chain *chain)
{
        struct tcf_proto *tp;
        int err;

        tp = kzalloc(sizeof(*tp), GFP_KERNEL);
        if (!tp)
                return ERR_PTR(-ENOBUFS);

        err = -ENOENT;
        tp->ops = tcf_proto_lookup_ops(kind);
        if (!tp->ops) {
#ifdef CONFIG_MODULES
                rtnl_unlock();
                request_module("cls_%s", kind);
                rtnl_lock();
                tp->ops = tcf_proto_lookup_ops(kind);
                /* We dropped the RTNL semaphore in order to perform
                 * the module load. So, even if we succeeded in loading
                 * the module we have to replay the request. We indicate
                 * this using -EAGAIN.
                 */
                if (tp->ops) {
                        module_put(tp->ops->owner);
                        err = -EAGAIN;
                } else {
                        err = -ENOENT;
                }
                goto errout;
#endif
        }
        tp->classify = tp->ops->classify;
        tp->protocol = protocol;
        tp->prio = prio;
        tp->classid = parent;
        tp->q = q;
        tp->chain = chain;

        err = tp->ops->init(tp);
        if (err) {
                module_put(tp->ops->owner);
                goto errout;
        }
        return tp;

errout:
        kfree(tp);
        return ERR_PTR(err);
}

static void tcf_proto_destroy(struct tcf_proto *tp)
{
        tp->ops->destroy(tp);
        module_put(tp->ops->owner);
        kfree_rcu(tp, rcu);
}

static struct tcf_chain *tcf_chain_create(struct tcf_block *block,
                                          u32 chain_index)
{
        struct tcf_chain *chain;

        chain = kzalloc(sizeof(*chain), GFP_KERNEL);
        if (!chain)
                return NULL;
        list_add_tail(&chain->list, &block->chain_list);
        chain->block = block;
        chain->index = chain_index;
        chain->refcnt = 1;
        return chain;
}

static void tcf_chain_head_change(struct tcf_chain *chain,
                                  struct tcf_proto *tp_head)
{
        if (chain->chain_head_change)
                chain->chain_head_change(tp_head,
                                         chain->chain_head_change_priv);
}

static void tcf_chain_flush(struct tcf_chain *chain)
{
        struct tcf_proto *tp = rtnl_dereference(chain->filter_chain);

        tcf_chain_head_change(chain, NULL);
        while (tp) {
                RCU_INIT_POINTER(chain->filter_chain, tp->next);
                tcf_proto_destroy(tp);
                tp = rtnl_dereference(chain->filter_chain);
                tcf_chain_put(chain);
        }
}

static void tcf_chain_destroy(struct tcf_chain *chain)
{
        list_del(&chain->list);
        kfree(chain);
}

static void tcf_chain_hold(struct tcf_chain *chain)
{
        ++chain->refcnt;
}

struct tcf_chain *tcf_chain_get(struct tcf_block *block, u32 chain_index,
                                bool create)
{
        struct tcf_chain *chain;

        list_for_each_entry(chain, &block->chain_list, list) {
                if (chain->index == chain_index) {
                        tcf_chain_hold(chain);
                        return chain;
                }
        }

        return create ? tcf_chain_create(block, chain_index) : NULL;
}
EXPORT_SYMBOL(tcf_chain_get);

void tcf_chain_put(struct tcf_chain *chain)
{
        if (--chain->refcnt == 0)
                tcf_chain_destroy(chain);
}
EXPORT_SYMBOL(tcf_chain_put);

static void tcf_block_offload_cmd(struct tcf_block *block, struct Qdisc *q,
                                  struct tcf_block_ext_info *ei,
                                  enum tc_block_command command)
{
        struct net_device *dev = q->dev_queue->dev;
        struct tc_block_offload bo = {};

        if (!dev->netdev_ops->ndo_setup_tc)
                return;
        bo.command = command;
        bo.binder_type = ei->binder_type;
        bo.block = block;
        dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_BLOCK, &bo);
}

static void tcf_block_offload_bind(struct tcf_block *block, struct Qdisc *q,
                                   struct tcf_block_ext_info *ei)
{
        tcf_block_offload_cmd(block, q, ei, TC_BLOCK_BIND);
}

static void tcf_block_offload_unbind(struct tcf_block *block, struct Qdisc *q,
                                     struct tcf_block_ext_info *ei)
{
        tcf_block_offload_cmd(block, q, ei, TC_BLOCK_UNBIND);
}

int tcf_block_get_ext(struct tcf_block **p_block, struct Qdisc *q,
                      struct tcf_block_ext_info *ei)
{
        struct tcf_block *block = kzalloc(sizeof(*block), GFP_KERNEL);
        struct tcf_chain *chain;
        int err;

        if (!block)
                return -ENOMEM;
        INIT_LIST_HEAD(&block->chain_list);
        INIT_LIST_HEAD(&block->cb_list);

        /* Create chain 0 by default, it has to be always present. */
        chain = tcf_chain_create(block, 0);
        if (!chain) {
                err = -ENOMEM;
                goto err_chain_create;
        }
        WARN_ON(!ei->chain_head_change);
        chain->chain_head_change = ei->chain_head_change;
        chain->chain_head_change_priv = ei->chain_head_change_priv;
        block->net = qdisc_net(q);
        block->q = q;
        tcf_block_offload_bind(block, q, ei);
        *p_block = block;
        return 0;

err_chain_create:
        kfree(block);
        return err;
}
EXPORT_SYMBOL(tcf_block_get_ext);

static void tcf_chain_head_change_dflt(struct tcf_proto *tp_head, void *priv)
{
        struct tcf_proto __rcu **p_filter_chain = priv;

        rcu_assign_pointer(*p_filter_chain, tp_head);
}

int tcf_block_get(struct tcf_block **p_block,
                  struct tcf_proto __rcu **p_filter_chain, struct Qdisc *q)
{
        struct tcf_block_ext_info ei = {
                .chain_head_change = tcf_chain_head_change_dflt,
                .chain_head_change_priv = p_filter_chain,
        };

        WARN_ON(!p_filter_chain);
        return tcf_block_get_ext(p_block, q, &ei);
}
EXPORT_SYMBOL(tcf_block_get);

static void tcf_block_put_final(struct work_struct *work)
{
        struct tcf_block *block = container_of(work, struct tcf_block, work);
        struct tcf_chain *chain, *tmp;

        rtnl_lock();

        /* At this point, all the chains should have refcnt == 1. */
        list_for_each_entry_safe(chain, tmp, &block->chain_list, list)
                tcf_chain_put(chain);
        rtnl_unlock();
        kfree(block);
}

/* XXX: Standalone actions are not allowed to jump to any chain, and bound
 * actions should be all removed after flushing.
 */
void tcf_block_put_ext(struct tcf_block *block, struct Qdisc *q,
                       struct tcf_block_ext_info *ei)
{
        struct tcf_chain *chain;

        /* Hold a refcnt for all chains, except 0, so that they don't disappear
         * while we are iterating.
         */
        list_for_each_entry(chain, &block->chain_list, list)
                if (chain->index)
                        tcf_chain_hold(chain);

        list_for_each_entry(chain, &block->chain_list, list)
                tcf_chain_flush(chain);

        tcf_block_offload_unbind(block, q, ei);

        INIT_WORK(&block->work, tcf_block_put_final);
        /* Wait for existing RCU callbacks to cool down, make sure their works
         * have been queued before this. We can not flush pending works here
         * because we are holding the RTNL lock.
         */
        rcu_barrier();
        tcf_queue_work(&block->work);
}
EXPORT_SYMBOL(tcf_block_put_ext);

void tcf_block_put(struct tcf_block *block)
{
        struct tcf_block_ext_info ei = {0, };

        if (!block)
                return;
        tcf_block_put_ext(block, block->q, &ei);
}

EXPORT_SYMBOL(tcf_block_put);

struct tcf_block_cb {
        struct list_head list;
        tc_setup_cb_t *cb;
        void *cb_ident;
        void *cb_priv;
        unsigned int refcnt;
};

void *tcf_block_cb_priv(struct tcf_block_cb *block_cb)
{
        return block_cb->cb_priv;
}
EXPORT_SYMBOL(tcf_block_cb_priv);

struct tcf_block_cb *tcf_block_cb_lookup(struct tcf_block *block,
                                         tc_setup_cb_t *cb, void *cb_ident)
{       struct tcf_block_cb *block_cb;

        list_for_each_entry(block_cb, &block->cb_list, list)
                if (block_cb->cb == cb && block_cb->cb_ident == cb_ident)
                        return block_cb;
        return NULL;
}
EXPORT_SYMBOL(tcf_block_cb_lookup);

void tcf_block_cb_incref(struct tcf_block_cb *block_cb)
{
        block_cb->refcnt++;
}
EXPORT_SYMBOL(tcf_block_cb_incref);

unsigned int tcf_block_cb_decref(struct tcf_block_cb *block_cb)
{
        return --block_cb->refcnt;
}
EXPORT_SYMBOL(tcf_block_cb_decref);

struct tcf_block_cb *__tcf_block_cb_register(struct tcf_block *block,
                                             tc_setup_cb_t *cb, void *cb_ident,
                                             void *cb_priv)
{
        struct tcf_block_cb *block_cb;

        block_cb = kzalloc(sizeof(*block_cb), GFP_KERNEL);
        if (!block_cb)
                return NULL;
        block_cb->cb = cb;
        block_cb->cb_ident = cb_ident;
        block_cb->cb_priv = cb_priv;
        list_add(&block_cb->list, &block->cb_list);
        return block_cb;
}
EXPORT_SYMBOL(__tcf_block_cb_register);

int tcf_block_cb_register(struct tcf_block *block,
                          tc_setup_cb_t *cb, void *cb_ident,
                          void *cb_priv)
{
        struct tcf_block_cb *block_cb;

        block_cb = __tcf_block_cb_register(block, cb, cb_ident, cb_priv);
        return block_cb ? 0 : -ENOMEM;
}
EXPORT_SYMBOL(tcf_block_cb_register);

void __tcf_block_cb_unregister(struct tcf_block_cb *block_cb)
{
        list_del(&block_cb->list);
        kfree(block_cb);
}
EXPORT_SYMBOL(__tcf_block_cb_unregister);

void tcf_block_cb_unregister(struct tcf_block *block,
                             tc_setup_cb_t *cb, void *cb_ident)
{
        struct tcf_block_cb *block_cb;

        block_cb = tcf_block_cb_lookup(block, cb, cb_ident);
        if (!block_cb)
                return;
        __tcf_block_cb_unregister(block_cb);
}
EXPORT_SYMBOL(tcf_block_cb_unregister);

static int tcf_block_cb_call(struct tcf_block *block, enum tc_setup_type type,
                             void *type_data, bool err_stop)
{
        struct tcf_block_cb *block_cb;
        int ok_count = 0;
        int err;

        list_for_each_entry(block_cb, &block->cb_list, list) {
                err = block_cb->cb(type, type_data, block_cb->cb_priv);
                if (err) {
                        if (err_stop)
                                return err;
                } else {
                        ok_count++;
                }
        }
        return ok_count;
}

/* Main classifier routine: scans classifier chain attached
 * to this qdisc, (optionally) tests for protocol and asks
 * specific classifiers.
 */
int tcf_classify(struct sk_buff *skb, const struct tcf_proto *tp,
                 struct tcf_result *res, bool compat_mode)
{
        __be16 protocol = tc_skb_protocol(skb);
#ifdef CONFIG_NET_CLS_ACT
        const int max_reclassify_loop = 4;
        const struct tcf_proto *orig_tp = tp;
        const struct tcf_proto *first_tp;
        int limit = 0;

reclassify:
#endif
        for (; tp; tp = rcu_dereference_bh(tp->next)) {
                int err;

                if (tp->protocol != protocol &&
                    tp->protocol != htons(ETH_P_ALL))
                        continue;

                err = tp->classify(skb, tp, res);
#ifdef CONFIG_NET_CLS_ACT
                if (unlikely(err == TC_ACT_RECLASSIFY && !compat_mode)) {
                        first_tp = orig_tp;
                        goto reset;
                } else if (unlikely(TC_ACT_EXT_CMP(err, TC_ACT_GOTO_CHAIN))) {
                        first_tp = res->goto_tp;
                        goto reset;
                }
#endif
                if (err >= 0)
                        return err;
        }

        return TC_ACT_UNSPEC; /* signal: continue lookup */
#ifdef CONFIG_NET_CLS_ACT
reset:
        if (unlikely(limit++ >= max_reclassify_loop)) {
                net_notice_ratelimited("%s: reclassify loop, rule prio %u, protocol %02x\n",
                                       tp->q->ops->id, tp->prio & 0xffff,
                                       ntohs(tp->protocol));
                return TC_ACT_SHOT;
        }

        tp = first_tp;
        protocol = tc_skb_protocol(skb);
        goto reclassify;
#endif
}
EXPORT_SYMBOL(tcf_classify);

struct tcf_chain_info {
        struct tcf_proto __rcu **pprev;
        struct tcf_proto __rcu *next;
};

static struct tcf_proto *tcf_chain_tp_prev(struct tcf_chain_info *chain_info)
{
        return rtnl_dereference(*chain_info->pprev);
}

static void tcf_chain_tp_insert(struct tcf_chain *chain,
                                struct tcf_chain_info *chain_info,
                                struct tcf_proto *tp)
{
        if (*chain_info->pprev == chain->filter_chain)
                tcf_chain_head_change(chain, tp);
        RCU_INIT_POINTER(tp->next, tcf_chain_tp_prev(chain_info));
        rcu_assign_pointer(*chain_info->pprev, tp);
        tcf_chain_hold(chain);
}

static void tcf_chain_tp_remove(struct tcf_chain *chain,
                                struct tcf_chain_info *chain_info,
                                struct tcf_proto *tp)
{
        struct tcf_proto *next = rtnl_dereference(chain_info->next);

        if (tp == chain->filter_chain)
                tcf_chain_head_change(chain, next);
        RCU_INIT_POINTER(*chain_info->pprev, next);
        tcf_chain_put(chain);
}

static struct tcf_proto *tcf_chain_tp_find(struct tcf_chain *chain,
                                           struct tcf_chain_info *chain_info,
                                           u32 protocol, u32 prio,
                                           bool prio_allocate)
{
        struct tcf_proto **pprev;
        struct tcf_proto *tp;

        /* Check the chain for existence of proto-tcf with this priority */
        for (pprev = &chain->filter_chain;
             (tp = rtnl_dereference(*pprev)); pprev = &tp->next) {
                if (tp->prio >= prio) {
                        if (tp->prio == prio) {
                                if (prio_allocate ||
                                    (tp->protocol != protocol && protocol))
                                        return ERR_PTR(-EINVAL);
                        } else {
                                tp = NULL;
                        }
                        break;
                }
        }
        chain_info->pprev = pprev;
        chain_info->next = tp ? tp->next : NULL;
        return tp;
}

static int tcf_fill_node(struct net *net, struct sk_buff *skb,
                         struct tcf_proto *tp, struct Qdisc *q, u32 parent,
                         void *fh, u32 portid, u32 seq, u16 flags, int event)
{
        struct tcmsg *tcm;
        struct nlmsghdr  *nlh;
        unsigned char *b = skb_tail_pointer(skb);

        nlh = nlmsg_put(skb, portid, seq, event, sizeof(*tcm), flags);
        if (!nlh)
                goto out_nlmsg_trim;
        tcm = nlmsg_data(nlh);
        tcm->tcm_family = AF_UNSPEC;
        tcm->tcm__pad1 = 0;
        tcm->tcm__pad2 = 0;
        tcm->tcm_ifindex = qdisc_dev(q)->ifindex;
        tcm->tcm_parent = parent;
        tcm->tcm_info = TC_H_MAKE(tp->prio, tp->protocol);
        if (nla_put_string(skb, TCA_KIND, tp->ops->kind))
                goto nla_put_failure;
        if (nla_put_u32(skb, TCA_CHAIN, tp->chain->index))
                goto nla_put_failure;
        if (!fh) {
                tcm->tcm_handle = 0;
        } else {
                if (tp->ops->dump && tp->ops->dump(net, tp, fh, skb, tcm) < 0)
                        goto nla_put_failure;
        }
        nlh->nlmsg_len = skb_tail_pointer(skb) - b;
        return skb->len;

out_nlmsg_trim:
nla_put_failure:
        nlmsg_trim(skb, b);
        return -1;
}

static int tfilter_notify(struct net *net, struct sk_buff *oskb,
                          struct nlmsghdr *n, struct tcf_proto *tp,
                          struct Qdisc *q, u32 parent,
                          void *fh, int event, bool unicast)
{
        struct sk_buff *skb;
        u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;

        skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
        if (!skb)
                return -ENOBUFS;

        if (tcf_fill_node(net, skb, tp, q, parent, fh, portid, n->nlmsg_seq,
                          n->nlmsg_flags, event) <= 0) {
                kfree_skb(skb);
                return -EINVAL;
        }

        if (unicast)
                return netlink_unicast(net->rtnl, skb, portid, MSG_DONTWAIT);

        return rtnetlink_send(skb, net, portid, RTNLGRP_TC,
                              n->nlmsg_flags & NLM_F_ECHO);
}

static int tfilter_del_notify(struct net *net, struct sk_buff *oskb,
                              struct nlmsghdr *n, struct tcf_proto *tp,
                              struct Qdisc *q, u32 parent,
                              void *fh, bool unicast, bool *last)
{
        struct sk_buff *skb;
        u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
        int err;

        skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
        if (!skb)
                return -ENOBUFS;

        if (tcf_fill_node(net, skb, tp, q, parent, fh, portid, n->nlmsg_seq,
                          n->nlmsg_flags, RTM_DELTFILTER) <= 0) {
                kfree_skb(skb);
                return -EINVAL;
        }

        err = tp->ops->delete(tp, fh, last);
        if (err) {
                kfree_skb(skb);
                return err;
        }

        if (unicast)
                return netlink_unicast(net->rtnl, skb, portid, MSG_DONTWAIT);

        return rtnetlink_send(skb, net, portid, RTNLGRP_TC,
                              n->nlmsg_flags & NLM_F_ECHO);
}

static void tfilter_notify_chain(struct net *net, struct sk_buff *oskb,
                                 struct Qdisc *q, u32 parent,
                                 struct nlmsghdr *n,
                                 struct tcf_chain *chain, int event)
{
        struct tcf_proto *tp;

        for (tp = rtnl_dereference(chain->filter_chain);
             tp; tp = rtnl_dereference(tp->next))
                tfilter_notify(net, oskb, n, tp, q, parent, 0, event, false);
}

/* Add/change/delete/get a filter node */

static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
                          struct netlink_ext_ack *extack)
{
        struct net *net = sock_net(skb->sk);
        struct nlattr *tca[TCA_MAX + 1];
        struct tcmsg *t;
        u32 protocol;
        u32 prio;
        bool prio_allocate;
        u32 parent;
        u32 chain_index;
        struct net_device *dev;
        struct Qdisc  *q;
        struct tcf_chain_info chain_info;
        struct tcf_chain *chain = NULL;
        struct tcf_block *block;
        struct tcf_proto *tp;
        const struct Qdisc_class_ops *cops;
        unsigned long cl;
        void *fh;
        int err;
        int tp_created;

        if ((n->nlmsg_type != RTM_GETTFILTER) &&
            !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
                return -EPERM;

replay:
        tp_created = 0;

        err = nlmsg_parse(n, sizeof(*t), tca, TCA_MAX, NULL, extack);
        if (err < 0)
                return err;

        t = nlmsg_data(n);
        protocol = TC_H_MIN(t->tcm_info);
        prio = TC_H_MAJ(t->tcm_info);
        prio_allocate = false;
        parent = t->tcm_parent;
        cl = 0;

        if (prio == 0) {
                switch (n->nlmsg_type) {
                case RTM_DELTFILTER:
                        if (protocol || t->tcm_handle || tca[TCA_KIND])
                                return -ENOENT;
                        break;
                case RTM_NEWTFILTER:
                        /* If no priority is provided by the user,
                         * we allocate one.
                         */
                        if (n->nlmsg_flags & NLM_F_CREATE) {
                                prio = TC_H_MAKE(0x80000000U, 0U);
                                prio_allocate = true;
                                break;
                        }
                        /* fall-through */
                default:
                        return -ENOENT;
                }
        }

        /* Find head of filter chain. */

        /* Find link */
        dev = __dev_get_by_index(net, t->tcm_ifindex);
        if (dev == NULL)
                return -ENODEV;

        /* Find qdisc */
        if (!parent) {
                q = dev->qdisc;
                parent = q->handle;
        } else {
                q = qdisc_lookup(dev, TC_H_MAJ(t->tcm_parent));
                if (q == NULL)
                        return -EINVAL;
        }

        /* Is it classful? */
        cops = q->ops->cl_ops;
        if (!cops)
                return -EINVAL;

        if (!cops->tcf_block)
                return -EOPNOTSUPP;

        /* Do we search for filter, attached to class? */
        if (TC_H_MIN(parent)) {
                cl = cops->find(q, parent);
                if (cl == 0)
                        return -ENOENT;
        }

        /* And the last stroke */
        block = cops->tcf_block(q, cl);
        if (!block) {
                err = -EINVAL;
                goto errout;
        }

        chain_index = tca[TCA_CHAIN] ? nla_get_u32(tca[TCA_CHAIN]) : 0;
        if (chain_index > TC_ACT_EXT_VAL_MASK) {
                err = -EINVAL;
                goto errout;
        }
        chain = tcf_chain_get(block, chain_index,
                              n->nlmsg_type == RTM_NEWTFILTER);
        if (!chain) {
                err = n->nlmsg_type == RTM_NEWTFILTER ? -ENOMEM : -EINVAL;
                goto errout;
        }

        if (n->nlmsg_type == RTM_DELTFILTER && prio == 0) {
                tfilter_notify_chain(net, skb, q, parent, n,
                                     chain, RTM_DELTFILTER);
                tcf_chain_flush(chain);
                err = 0;
                goto errout;
        }

        tp = tcf_chain_tp_find(chain, &chain_info, protocol,
                               prio, prio_allocate);
        if (IS_ERR(tp)) {
                err = PTR_ERR(tp);
                goto errout;
        }

        if (tp == NULL) {
                /* Proto-tcf does not exist, create new one */

                if (tca[TCA_KIND] == NULL || !protocol) {
                        err = -EINVAL;
                        goto errout;
                }

                if (n->nlmsg_type != RTM_NEWTFILTER ||
                    !(n->nlmsg_flags & NLM_F_CREATE)) {
                        err = -ENOENT;
                        goto errout;
                }

                if (prio_allocate)
                        prio = tcf_auto_prio(tcf_chain_tp_prev(&chain_info));

                tp = tcf_proto_create(nla_data(tca[TCA_KIND]),
                                      protocol, prio, parent, q, chain);
                if (IS_ERR(tp)) {
                        err = PTR_ERR(tp);
                        goto errout;
                }
                tp_created = 1;
        } else if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], tp->ops->kind)) {
                err = -EINVAL;
                goto errout;
        }

        fh = tp->ops->get(tp, t->tcm_handle);

        if (!fh) {
                if (n->nlmsg_type == RTM_DELTFILTER && t->tcm_handle == 0) {
                        tcf_chain_tp_remove(chain, &chain_info, tp);
                        tfilter_notify(net, skb, n, tp, q, parent, fh,
                                       RTM_DELTFILTER, false);
                        tcf_proto_destroy(tp);
                        err = 0;
                        goto errout;
                }

                if (n->nlmsg_type != RTM_NEWTFILTER ||
                    !(n->nlmsg_flags & NLM_F_CREATE)) {
                        err = -ENOENT;
                        goto errout;
                }
        } else {
                bool last;

                switch (n->nlmsg_type) {
                case RTM_NEWTFILTER:
                        if (n->nlmsg_flags & NLM_F_EXCL) {
                                if (tp_created)
                                        tcf_proto_destroy(tp);
                                err = -EEXIST;
                                goto errout;
                        }
                        break;
                case RTM_DELTFILTER:
                        err = tfilter_del_notify(net, skb, n, tp, q, parent,
                                                 fh, false, &last);
                        if (err)
                                goto errout;
                        if (last) {
                                tcf_chain_tp_remove(chain, &chain_info, tp);
                                tcf_proto_destroy(tp);
                        }
                        goto errout;
                case RTM_GETTFILTER:
                        err = tfilter_notify(net, skb, n, tp, q, parent, fh,
                                             RTM_NEWTFILTER, true);
                        goto errout;
                default:
                        err = -EINVAL;
                        goto errout;
                }
        }

        err = tp->ops->change(net, skb, tp, cl, t->tcm_handle, tca, &fh,
                              n->nlmsg_flags & NLM_F_CREATE ? TCA_ACT_NOREPLACE : TCA_ACT_REPLACE);
        if (err == 0) {
                if (tp_created)
                        tcf_chain_tp_insert(chain, &chain_info, tp);
                tfilter_notify(net, skb, n, tp, q, parent, fh,
                               RTM_NEWTFILTER, false);
        } else {
                if (tp_created)
                        tcf_proto_destroy(tp);
        }

errout:
        if (chain)
                tcf_chain_put(chain);
        if (err == -EAGAIN)
                /* Replay the request. */
                goto replay;
        return err;
}

struct tcf_dump_args {
        struct tcf_walker w;
        struct sk_buff *skb;
        struct netlink_callback *cb;
        struct Qdisc *q;
        u32 parent;
};

static int tcf_node_dump(struct tcf_proto *tp, void *n, struct tcf_walker *arg)
{
        struct tcf_dump_args *a = (void *)arg;
        struct net *net = sock_net(a->skb->sk);

        return tcf_fill_node(net, a->skb, tp, a->q, a->parent,
                             n, NETLINK_CB(a->cb->skb).portid,
                             a->cb->nlh->nlmsg_seq, NLM_F_MULTI,
                             RTM_NEWTFILTER);
}

static bool tcf_chain_dump(struct tcf_chain *chain, struct Qdisc *q, u32 parent,
                           struct sk_buff *skb, struct netlink_callback *cb,
                           long index_start, long *p_index)
{
        struct net *net = sock_net(skb->sk);
        struct tcmsg *tcm = nlmsg_data(cb->nlh);
        struct tcf_dump_args arg;
        struct tcf_proto *tp;

        for (tp = rtnl_dereference(chain->filter_chain);
             tp; tp = rtnl_dereference(tp->next), (*p_index)++) {
                if (*p_index < index_start)
                        continue;
                if (TC_H_MAJ(tcm->tcm_info) &&
                    TC_H_MAJ(tcm->tcm_info) != tp->prio)
                        continue;
                if (TC_H_MIN(tcm->tcm_info) &&
                    TC_H_MIN(tcm->tcm_info) != tp->protocol)
                        continue;
                if (*p_index > index_start)
                        memset(&cb->args[1], 0,
                               sizeof(cb->args) - sizeof(cb->args[0]));
                if (cb->args[1] == 0) {
                        if (tcf_fill_node(net, skb, tp, q, parent, 0,
                                          NETLINK_CB(cb->skb).portid,
                                          cb->nlh->nlmsg_seq, NLM_F_MULTI,
                                          RTM_NEWTFILTER) <= 0)
                                return false;

                        cb->args[1] = 1;
                }
                if (!tp->ops->walk)
                        continue;
                arg.w.fn = tcf_node_dump;
                arg.skb = skb;
                arg.cb = cb;
                arg.q = q;
                arg.parent = parent;
                arg.w.stop = 0;
                arg.w.skip = cb->args[1] - 1;
                arg.w.count = 0;
                tp->ops->walk(tp, &arg.w);
                cb->args[1] = arg.w.count + 1;
                if (arg.w.stop)
                        return false;
        }
        return true;
}

/* called with RTNL */
static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb)
{
        struct net *net = sock_net(skb->sk);
        struct nlattr *tca[TCA_MAX + 1];
        struct net_device *dev;
        struct Qdisc *q;
        struct tcf_block *block;
        struct tcf_chain *chain;
        struct tcmsg *tcm = nlmsg_data(cb->nlh);
        unsigned long cl = 0;
        const struct Qdisc_class_ops *cops;
        long index_start;
        long index;
        u32 parent;
        int err;

        if (nlmsg_len(cb->nlh) < sizeof(*tcm))
                return skb->len;

        err = nlmsg_parse(cb->nlh, sizeof(*tcm), tca, TCA_MAX, NULL, NULL);
        if (err)
                return err;

        dev = __dev_get_by_index(net, tcm->tcm_ifindex);
        if (!dev)
                return skb->len;

        parent = tcm->tcm_parent;
        if (!parent) {
                q = dev->qdisc;
                parent = q->handle;
        } else {
                q = qdisc_lookup(dev, TC_H_MAJ(tcm->tcm_parent));
        }
        if (!q)
                goto out;
        cops = q->ops->cl_ops;
        if (!cops)
                goto out;
        if (!cops->tcf_block)
                goto out;
        if (TC_H_MIN(tcm->tcm_parent)) {
                cl = cops->find(q, tcm->tcm_parent);
                if (cl == 0)
                        goto out;
        }
        block = cops->tcf_block(q, cl);
        if (!block)
                goto out;

        index_start = cb->args[0];
        index = 0;

        list_for_each_entry(chain, &block->chain_list, list) {
                if (tca[TCA_CHAIN] &&
                    nla_get_u32(tca[TCA_CHAIN]) != chain->index)
                        continue;
                if (!tcf_chain_dump(chain, q, parent, skb, cb,
                                    index_start, &index))
                        break;
        }

        cb->args[0] = index;

out:
        return skb->len;
}

void tcf_exts_destroy(struct tcf_exts *exts)
{
#ifdef CONFIG_NET_CLS_ACT
        LIST_HEAD(actions);

        ASSERT_RTNL();
        tcf_exts_to_list(exts, &actions);
        tcf_action_destroy(&actions, TCA_ACT_UNBIND);
        kfree(exts->actions);
        exts->nr_actions = 0;
#endif
}
EXPORT_SYMBOL(tcf_exts_destroy);

int tcf_exts_validate(struct net *net, struct tcf_proto *tp, struct nlattr **tb,
                      struct nlattr *rate_tlv, struct tcf_exts *exts, bool ovr)
{
#ifdef CONFIG_NET_CLS_ACT
        {
                struct tc_action *act;

                if (exts->police && tb[exts->police]) {
                        act = tcf_action_init_1(net, tp, tb[exts->police],
                                                rate_tlv, "police", ovr,
                                                TCA_ACT_BIND);
                        if (IS_ERR(act))
                                return PTR_ERR(act);

                        act->type = exts->type = TCA_OLD_COMPAT;
                        exts->actions[0] = act;
                        exts->nr_actions = 1;
                } else if (exts->action && tb[exts->action]) {
                        LIST_HEAD(actions);
                        int err, i = 0;

                        err = tcf_action_init(net, tp, tb[exts->action],
                                              rate_tlv, NULL, ovr, TCA_ACT_BIND,
                                              &actions);
                        if (err)
                                return err;
                        list_for_each_entry(act, &actions, list)
                                exts->actions[i++] = act;
                        exts->nr_actions = i;
                }
                exts->net = net;
        }
#else
        if ((exts->action && tb[exts->action]) ||
            (exts->police && tb[exts->police]))
                return -EOPNOTSUPP;
#endif

        return 0;
}
EXPORT_SYMBOL(tcf_exts_validate);

void tcf_exts_change(struct tcf_exts *dst, struct tcf_exts *src)
{
#ifdef CONFIG_NET_CLS_ACT
        struct tcf_exts old = *dst;

        *dst = *src;
        tcf_exts_destroy(&old);
#endif
}
EXPORT_SYMBOL(tcf_exts_change);

#ifdef CONFIG_NET_CLS_ACT
static struct tc_action *tcf_exts_first_act(struct tcf_exts *exts)
{
        if (exts->nr_actions == 0)
                return NULL;
        else
                return exts->actions[0];
}
#endif

int tcf_exts_dump(struct sk_buff *skb, struct tcf_exts *exts)
{
#ifdef CONFIG_NET_CLS_ACT
        struct nlattr *nest;

        if (exts->action && tcf_exts_has_actions(exts)) {
                /*
                 * again for backward compatible mode - we want
                 * to work with both old and new modes of entering
                 * tc data even if iproute2  was newer - jhs
                 */
                if (exts->type != TCA_OLD_COMPAT) {
                        LIST_HEAD(actions);

                        nest = nla_nest_start(skb, exts->action);
                        if (nest == NULL)
                                goto nla_put_failure;

                        tcf_exts_to_list(exts, &actions);
                        if (tcf_action_dump(skb, &actions, 0, 0) < 0)
                                goto nla_put_failure;
                        nla_nest_end(skb, nest);
                } else if (exts->police) {
                        struct tc_action *act = tcf_exts_first_act(exts);
                        nest = nla_nest_start(skb, exts->police);
                        if (nest == NULL || !act)
                                goto nla_put_failure;
                        if (tcf_action_dump_old(skb, act, 0, 0) < 0)
                                goto nla_put_failure;
                        nla_nest_end(skb, nest);
                }
        }
        return 0;

nla_put_failure:
        nla_nest_cancel(skb, nest);
        return -1;
#else
        return 0;
#endif
}
EXPORT_SYMBOL(tcf_exts_dump);


int tcf_exts_dump_stats(struct sk_buff *skb, struct tcf_exts *exts)
{
#ifdef CONFIG_NET_CLS_ACT
        struct tc_action *a = tcf_exts_first_act(exts);
        if (a != NULL && tcf_action_copy_stats(skb, a, 1) < 0)
                return -1;
#endif
        return 0;
}
EXPORT_SYMBOL(tcf_exts_dump_stats);

static int tc_exts_setup_cb_egdev_call(struct tcf_exts *exts,
                                       enum tc_setup_type type,
                                       void *type_data, bool err_stop)
{
        int ok_count = 0;
#ifdef CONFIG_NET_CLS_ACT
        const struct tc_action *a;
        struct net_device *dev;
        int i, ret;

        if (!tcf_exts_has_actions(exts))
                return 0;

        for (i = 0; i < exts->nr_actions; i++) {
                a = exts->actions[i];
                if (!a->ops->get_dev)
                        continue;
                dev = a->ops->get_dev(a);
                if (!dev)
                        continue;
                ret = tc_setup_cb_egdev_call(dev, type, type_data, err_stop);
                if (ret < 0)
                        return ret;
                ok_count += ret;
        }
#endif
        return ok_count;
}

int tc_setup_cb_call(struct tcf_block *block, struct tcf_exts *exts,
                     enum tc_setup_type type, void *type_data, bool err_stop)
{
        int ok_count;
        int ret;

        ret = tcf_block_cb_call(block, type, type_data, err_stop);
        if (ret < 0)
                return ret;
        ok_count = ret;

        if (!exts)
                return ok_count;
        ret = tc_exts_setup_cb_egdev_call(exts, type, type_data, err_stop);
        if (ret < 0)
                return ret;
        ok_count += ret;

        return ok_count;
}
EXPORT_SYMBOL(tc_setup_cb_call);

static int __init tc_filter_init(void)
{
        tc_filter_wq = alloc_ordered_workqueue("tc_filter_workqueue", 0);
        if (!tc_filter_wq)
                return -ENOMEM;

        rtnl_register(PF_UNSPEC, RTM_NEWTFILTER, tc_ctl_tfilter, NULL, 0);
        rtnl_register(PF_UNSPEC, RTM_DELTFILTER, tc_ctl_tfilter, NULL, 0);
        rtnl_register(PF_UNSPEC, RTM_GETTFILTER, tc_ctl_tfilter,
                      tc_dump_tfilter, 0);

        return 0;
}

subsys_initcall(tc_filter_init);