net: sched: add ipset ematch
Can be used to match packets against netfilter ip sets created via ipset(8).
skb->sk_iif is used as 'incoming interface', skb->dev is 'outgoing interface'.
Since ipset is usually called from netfilter, the ematch
initializes a fake xt_action_param, pulls the ip header into the
linear area and also sets skb->data to the IP header (otherwise
matching Layer 4 set types doesn't work).
Tested-by: Mr Dash Four <mr.dash.four@googlemail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/em_ipset.c b/net/sched/em_ipset.c
new file mode 100644
index 0000000..3130320
--- /dev/null
+++ b/net/sched/em_ipset.c
@@ -0,0 +1,135 @@
+/*
+ * net/sched/em_ipset.c ipset ematch
+ *
+ * Copyright (c) 2012 Florian Westphal <fw@strlen.de>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ */
+
+#include <linux/gfp.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/skbuff.h>
+#include <linux/netfilter/xt_set.h>
+#include <linux/ipv6.h>
+#include <net/ip.h>
+#include <net/pkt_cls.h>
+
+static int em_ipset_change(struct tcf_proto *tp, void *data, int data_len,
+ struct tcf_ematch *em)
+{
+ struct xt_set_info *set = data;
+ ip_set_id_t index;
+
+ if (data_len != sizeof(*set))
+ return -EINVAL;
+
+ index = ip_set_nfnl_get_byindex(set->index);
+ if (index == IPSET_INVALID_ID)
+ return -ENOENT;
+
+ em->datalen = sizeof(*set);
+ em->data = (unsigned long)kmemdup(data, em->datalen, GFP_KERNEL);
+ if (em->data)
+ return 0;
+
+ ip_set_nfnl_put(index);
+ return -ENOMEM;
+}
+
+static void em_ipset_destroy(struct tcf_proto *p, struct tcf_ematch *em)
+{
+ const struct xt_set_info *set = (const void *) em->data;
+ if (set) {
+ ip_set_nfnl_put(set->index);
+ kfree((void *) em->data);
+ }
+}
+
+static int em_ipset_match(struct sk_buff *skb, struct tcf_ematch *em,
+ struct tcf_pkt_info *info)
+{
+ struct ip_set_adt_opt opt;
+ struct xt_action_param acpar;
+ const struct xt_set_info *set = (const void *) em->data;
+ struct net_device *dev, *indev = NULL;
+ int ret, network_offset;
+
+ switch (skb->protocol) {
+ case htons(ETH_P_IP):
+ acpar.family = NFPROTO_IPV4;
+ if (!pskb_network_may_pull(skb, sizeof(struct iphdr)))
+ return 0;
+ acpar.thoff = ip_hdrlen(skb);
+ break;
+ case htons(ETH_P_IPV6):
+ acpar.family = NFPROTO_IPV6;
+ if (!pskb_network_may_pull(skb, sizeof(struct ipv6hdr)))
+ return 0;
+ /* doesn't call ipv6_find_hdr() because ipset doesn't use thoff, yet */
+ acpar.thoff = sizeof(struct ipv6hdr);
+ break;
+ default:
+ return 0;
+ }
+
+ acpar.hooknum = 0;
+
+ opt.family = acpar.family;
+ opt.dim = set->dim;
+ opt.flags = set->flags;
+ opt.cmdflags = 0;
+ opt.timeout = ~0u;
+
+ network_offset = skb_network_offset(skb);
+ skb_pull(skb, network_offset);
+
+ dev = skb->dev;
+
+ rcu_read_lock();
+
+ if (dev && skb->skb_iif)
+ indev = dev_get_by_index_rcu(dev_net(dev), skb->skb_iif);
+
+ acpar.in = indev ? indev : dev;
+ acpar.out = dev;
+
+ ret = ip_set_test(set->index, skb, &acpar, &opt);
+
+ rcu_read_unlock();
+
+ skb_push(skb, network_offset);
+ return ret;
+}
+
+static struct tcf_ematch_ops em_ipset_ops = {
+ .kind = TCF_EM_IPSET,
+ .change = em_ipset_change,
+ .destroy = em_ipset_destroy,
+ .match = em_ipset_match,
+ .owner = THIS_MODULE,
+ .link = LIST_HEAD_INIT(em_ipset_ops.link)
+};
+
+static int __init init_em_ipset(void)
+{
+ return tcf_em_register(&em_ipset_ops);
+}
+
+static void __exit exit_em_ipset(void)
+{
+ tcf_em_unregister(&em_ipset_ops);
+}
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Florian Westphal <fw@strlen.de>");
+MODULE_DESCRIPTION("TC extended match for IP sets");
+
+module_init(init_em_ipset);
+module_exit(exit_em_ipset);
+
+MODULE_ALIAS_TCF_EMATCH(TCF_EM_IPSET);