netfilter: conntrack: Flush connections with a given mark
This patch adds support for selective flushing of conntrack mappings. By adding CTA_MARK and CTA_MARK_MASK to a delete-message, the mark (and mask) is checked before a connection is deleted while flushing. Configuring the flush is moved out of ctnetlink_del_conntrack(), and instead of calling nf_conntrack_flush_report(), we always call nf_ct_iterate_cleanup(). This enables us to only make one call from the new ctnetlink_flush_conntrack() and makes it easy to add more filter parameters. Filtering is done in the ctnetlink_filter_match()-function, which is also called from ctnetlink_dump_table(). ctnetlink_dump_filter has been renamed ctnetlink_filter, to indicated that it is no longer only used when dumping conntrack entries. Moreover, reject mark filters with -EOPNOTSUPP if no ct mark support is available. Signed-off-by: Kristian Evensen <kristian.evensen@gmail.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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@ -749,13 +749,47 @@ static int ctnetlink_done(struct netlink_callback *cb)
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return 0;
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}
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struct ctnetlink_dump_filter {
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struct ctnetlink_filter {
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struct {
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u_int32_t val;
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u_int32_t mask;
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} mark;
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};
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static struct ctnetlink_filter *
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ctnetlink_alloc_filter(const struct nlattr * const cda[])
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{
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#ifdef CONFIG_NF_CONNTRACK_MARK
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struct ctnetlink_filter *filter;
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filter = kzalloc(sizeof(*filter), GFP_KERNEL);
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if (filter == NULL)
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return ERR_PTR(-ENOMEM);
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filter->mark.val = ntohl(nla_get_be32(cda[CTA_MARK]));
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filter->mark.mask = ntohl(nla_get_be32(cda[CTA_MARK_MASK]));
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return filter;
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#else
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return ERR_PTR(-EOPNOTSUPP);
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#endif
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}
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static int ctnetlink_filter_match(struct nf_conn *ct, void *data)
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{
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struct ctnetlink_filter *filter = data;
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if (filter == NULL)
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return 1;
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#ifdef CONFIG_NF_CONNTRACK_MARK
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if ((ct->mark & filter->mark.mask) == filter->mark.val)
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return 1;
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#endif
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return 0;
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}
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static int
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ctnetlink_dump_table(struct sk_buff *skb, struct netlink_callback *cb)
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{
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@ -768,10 +802,6 @@ ctnetlink_dump_table(struct sk_buff *skb, struct netlink_callback *cb)
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int res;
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spinlock_t *lockp;
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#ifdef CONFIG_NF_CONNTRACK_MARK
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const struct ctnetlink_dump_filter *filter = cb->data;
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#endif
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last = (struct nf_conn *)cb->args[1];
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local_bh_disable();
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@ -798,12 +828,9 @@ restart:
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continue;
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cb->args[1] = 0;
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}
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#ifdef CONFIG_NF_CONNTRACK_MARK
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if (filter && !((ct->mark & filter->mark.mask) ==
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filter->mark.val)) {
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if (!ctnetlink_filter_match(ct, cb->data))
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continue;
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}
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#endif
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rcu_read_lock();
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res =
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ctnetlink_fill_info(skb, NETLINK_CB(cb->skb).portid,
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@ -1001,6 +1028,25 @@ static const struct nla_policy ct_nla_policy[CTA_MAX+1] = {
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.len = NF_CT_LABELS_MAX_SIZE },
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};
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static int ctnetlink_flush_conntrack(struct net *net,
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const struct nlattr * const cda[],
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u32 portid, int report)
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{
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struct ctnetlink_filter *filter = NULL;
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if (cda[CTA_MARK] && cda[CTA_MARK_MASK]) {
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filter = ctnetlink_alloc_filter(cda);
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if (IS_ERR(filter))
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return PTR_ERR(filter);
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}
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nf_ct_iterate_cleanup(net, ctnetlink_filter_match, filter,
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portid, report);
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kfree(filter);
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return 0;
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}
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static int
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ctnetlink_del_conntrack(struct sock *ctnl, struct sk_buff *skb,
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const struct nlmsghdr *nlh,
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@ -1024,11 +1070,9 @@ ctnetlink_del_conntrack(struct sock *ctnl, struct sk_buff *skb,
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else if (cda[CTA_TUPLE_REPLY])
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err = ctnetlink_parse_tuple(cda, &tuple, CTA_TUPLE_REPLY, u3);
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else {
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/* Flush the whole table */
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nf_conntrack_flush_report(net,
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NETLINK_CB(skb).portid,
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nlmsg_report(nlh));
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return 0;
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return ctnetlink_flush_conntrack(net, cda,
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NETLINK_CB(skb).portid,
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nlmsg_report(nlh));
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}
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if (err < 0)
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@ -1076,21 +1120,16 @@ ctnetlink_get_conntrack(struct sock *ctnl, struct sk_buff *skb,
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.dump = ctnetlink_dump_table,
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.done = ctnetlink_done,
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};
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#ifdef CONFIG_NF_CONNTRACK_MARK
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if (cda[CTA_MARK] && cda[CTA_MARK_MASK]) {
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struct ctnetlink_dump_filter *filter;
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struct ctnetlink_filter *filter;
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filter = kzalloc(sizeof(struct ctnetlink_dump_filter),
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GFP_ATOMIC);
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if (filter == NULL)
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return -ENOMEM;
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filter = ctnetlink_alloc_filter(cda);
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if (IS_ERR(filter))
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return PTR_ERR(filter);
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filter->mark.val = ntohl(nla_get_be32(cda[CTA_MARK]));
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filter->mark.mask =
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ntohl(nla_get_be32(cda[CTA_MARK_MASK]));
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c.data = filter;
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}
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#endif
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return netlink_dump_start(ctnl, skb, nlh, &c);
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}
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