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![Cong Wang](/assets/img/avatar_default.png)
Kernel automatically creates a tp for each (kind, protocol, priority) tuple, which has handle 0, when we add a new filter, but it still is left there after we remove our own, unless we don't specify the handle (literally means all the filters under the tuple). For example this one is left: # tc filter show dev eth0 filter parent 8001: protocol arp pref 49152 basic The user-space is hard to clean up these for kernel because filters like u32 are organized in a complex way. So kernel is responsible to remove it after all filters are gone. Each type of filter has its own way to store the filters, so each type has to provide its way to check if all filters are gone. Cc: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: Cong Wang <cwang@twopensource.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Acked-by: Jamal Hadi Salim<jhs@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
312 lines
6.8 KiB
C
312 lines
6.8 KiB
C
/*
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* net/sched/cls_basic.c Basic Packet Classifier.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* Authors: Thomas Graf <tgraf@suug.ch>
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*/
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/string.h>
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#include <linux/errno.h>
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#include <linux/rtnetlink.h>
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#include <linux/skbuff.h>
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#include <net/netlink.h>
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#include <net/act_api.h>
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#include <net/pkt_cls.h>
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struct basic_head {
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u32 hgenerator;
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struct list_head flist;
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struct rcu_head rcu;
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};
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struct basic_filter {
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u32 handle;
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struct tcf_exts exts;
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struct tcf_ematch_tree ematches;
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struct tcf_result res;
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struct tcf_proto *tp;
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struct list_head link;
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struct rcu_head rcu;
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};
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static int basic_classify(struct sk_buff *skb, const struct tcf_proto *tp,
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struct tcf_result *res)
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{
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int r;
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struct basic_head *head = rcu_dereference_bh(tp->root);
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struct basic_filter *f;
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list_for_each_entry_rcu(f, &head->flist, link) {
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if (!tcf_em_tree_match(skb, &f->ematches, NULL))
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continue;
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*res = f->res;
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r = tcf_exts_exec(skb, &f->exts, res);
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if (r < 0)
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continue;
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return r;
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}
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return -1;
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}
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static unsigned long basic_get(struct tcf_proto *tp, u32 handle)
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{
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unsigned long l = 0UL;
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struct basic_head *head = rtnl_dereference(tp->root);
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struct basic_filter *f;
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if (head == NULL)
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return 0UL;
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list_for_each_entry(f, &head->flist, link) {
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if (f->handle == handle) {
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l = (unsigned long) f;
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break;
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}
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}
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return l;
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}
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static int basic_init(struct tcf_proto *tp)
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{
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struct basic_head *head;
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head = kzalloc(sizeof(*head), GFP_KERNEL);
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if (head == NULL)
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return -ENOBUFS;
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INIT_LIST_HEAD(&head->flist);
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rcu_assign_pointer(tp->root, head);
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return 0;
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}
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static void basic_delete_filter(struct rcu_head *head)
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{
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struct basic_filter *f = container_of(head, struct basic_filter, rcu);
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tcf_exts_destroy(&f->exts);
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tcf_em_tree_destroy(&f->ematches);
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kfree(f);
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}
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static bool basic_destroy(struct tcf_proto *tp, bool force)
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{
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struct basic_head *head = rtnl_dereference(tp->root);
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struct basic_filter *f, *n;
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if (!force && !list_empty(&head->flist))
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return false;
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list_for_each_entry_safe(f, n, &head->flist, link) {
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list_del_rcu(&f->link);
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tcf_unbind_filter(tp, &f->res);
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call_rcu(&f->rcu, basic_delete_filter);
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}
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RCU_INIT_POINTER(tp->root, NULL);
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kfree_rcu(head, rcu);
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return true;
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}
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static int basic_delete(struct tcf_proto *tp, unsigned long arg)
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{
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struct basic_filter *f = (struct basic_filter *) arg;
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list_del_rcu(&f->link);
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tcf_unbind_filter(tp, &f->res);
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call_rcu(&f->rcu, basic_delete_filter);
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return 0;
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}
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static const struct nla_policy basic_policy[TCA_BASIC_MAX + 1] = {
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[TCA_BASIC_CLASSID] = { .type = NLA_U32 },
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[TCA_BASIC_EMATCHES] = { .type = NLA_NESTED },
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};
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static int basic_set_parms(struct net *net, struct tcf_proto *tp,
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struct basic_filter *f, unsigned long base,
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struct nlattr **tb,
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struct nlattr *est, bool ovr)
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{
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int err;
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struct tcf_exts e;
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struct tcf_ematch_tree t;
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tcf_exts_init(&e, TCA_BASIC_ACT, TCA_BASIC_POLICE);
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err = tcf_exts_validate(net, tp, tb, est, &e, ovr);
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if (err < 0)
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return err;
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err = tcf_em_tree_validate(tp, tb[TCA_BASIC_EMATCHES], &t);
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if (err < 0)
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goto errout;
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if (tb[TCA_BASIC_CLASSID]) {
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f->res.classid = nla_get_u32(tb[TCA_BASIC_CLASSID]);
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tcf_bind_filter(tp, &f->res, base);
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}
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tcf_exts_change(tp, &f->exts, &e);
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tcf_em_tree_change(tp, &f->ematches, &t);
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f->tp = tp;
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return 0;
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errout:
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tcf_exts_destroy(&e);
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return err;
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}
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static int basic_change(struct net *net, struct sk_buff *in_skb,
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struct tcf_proto *tp, unsigned long base, u32 handle,
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struct nlattr **tca, unsigned long *arg, bool ovr)
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{
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int err;
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struct basic_head *head = rtnl_dereference(tp->root);
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struct nlattr *tb[TCA_BASIC_MAX + 1];
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struct basic_filter *fold = (struct basic_filter *) *arg;
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struct basic_filter *fnew;
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if (tca[TCA_OPTIONS] == NULL)
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return -EINVAL;
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err = nla_parse_nested(tb, TCA_BASIC_MAX, tca[TCA_OPTIONS],
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basic_policy);
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if (err < 0)
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return err;
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if (fold != NULL) {
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if (handle && fold->handle != handle)
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return -EINVAL;
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}
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fnew = kzalloc(sizeof(*fnew), GFP_KERNEL);
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if (!fnew)
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return -ENOBUFS;
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tcf_exts_init(&fnew->exts, TCA_BASIC_ACT, TCA_BASIC_POLICE);
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err = -EINVAL;
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if (handle) {
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fnew->handle = handle;
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} else if (fold) {
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fnew->handle = fold->handle;
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} else {
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unsigned int i = 0x80000000;
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do {
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if (++head->hgenerator == 0x7FFFFFFF)
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head->hgenerator = 1;
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} while (--i > 0 && basic_get(tp, head->hgenerator));
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if (i <= 0) {
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pr_err("Insufficient number of handles\n");
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goto errout;
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}
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fnew->handle = head->hgenerator;
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}
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err = basic_set_parms(net, tp, fnew, base, tb, tca[TCA_RATE], ovr);
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if (err < 0)
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goto errout;
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*arg = (unsigned long)fnew;
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if (fold) {
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list_replace_rcu(&fold->link, &fnew->link);
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tcf_unbind_filter(tp, &fold->res);
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call_rcu(&fold->rcu, basic_delete_filter);
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} else {
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list_add_rcu(&fnew->link, &head->flist);
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}
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return 0;
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errout:
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kfree(fnew);
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return err;
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}
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static void basic_walk(struct tcf_proto *tp, struct tcf_walker *arg)
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{
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struct basic_head *head = rtnl_dereference(tp->root);
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struct basic_filter *f;
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list_for_each_entry(f, &head->flist, link) {
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if (arg->count < arg->skip)
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goto skip;
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if (arg->fn(tp, (unsigned long) f, arg) < 0) {
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arg->stop = 1;
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break;
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}
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skip:
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arg->count++;
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}
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}
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static int basic_dump(struct net *net, struct tcf_proto *tp, unsigned long fh,
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struct sk_buff *skb, struct tcmsg *t)
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{
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struct basic_filter *f = (struct basic_filter *) fh;
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struct nlattr *nest;
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if (f == NULL)
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return skb->len;
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t->tcm_handle = f->handle;
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nest = nla_nest_start(skb, TCA_OPTIONS);
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if (nest == NULL)
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goto nla_put_failure;
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if (f->res.classid &&
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nla_put_u32(skb, TCA_BASIC_CLASSID, f->res.classid))
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goto nla_put_failure;
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if (tcf_exts_dump(skb, &f->exts) < 0 ||
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tcf_em_tree_dump(skb, &f->ematches, TCA_BASIC_EMATCHES) < 0)
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goto nla_put_failure;
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nla_nest_end(skb, nest);
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if (tcf_exts_dump_stats(skb, &f->exts) < 0)
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goto nla_put_failure;
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return skb->len;
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nla_put_failure:
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nla_nest_cancel(skb, nest);
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return -1;
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}
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static struct tcf_proto_ops cls_basic_ops __read_mostly = {
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.kind = "basic",
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.classify = basic_classify,
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.init = basic_init,
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.destroy = basic_destroy,
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.get = basic_get,
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.change = basic_change,
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.delete = basic_delete,
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.walk = basic_walk,
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.dump = basic_dump,
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.owner = THIS_MODULE,
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};
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static int __init init_basic(void)
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{
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return register_tcf_proto_ops(&cls_basic_ops);
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}
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static void __exit exit_basic(void)
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{
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unregister_tcf_proto_ops(&cls_basic_ops);
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}
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module_init(init_basic)
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module_exit(exit_basic)
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MODULE_LICENSE("GPL");
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