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/include/linux/pkt_cls.h b/include/linux/pkt_cls.h
index 38fbd4b..082eafa 100644 (file)
--- a/include/linux/pkt_cls.h
+++ b/include/linux/pkt_cls.h
@@ -453,7 +453,8 @@ enum {
 #define        TCF_EM_TEXT             5
 #define        TCF_EM_VLAN             6
 #define        TCF_EM_CANID            7
-#define        TCF_EM_MAX              7
+#define        TCF_EM_IPSET            8
+#define        TCF_EM_MAX              8
 
 enum {
        TCF_EM_PROG_TC

diff --git a/net/sched/Kconfig b/net/sched/Kconfig
index 4a5d2bd..62fb51f 100644 (file)
--- a/net/sched/Kconfig
+++ b/net/sched/Kconfig
@@ -517,6 +517,16 @@ config NET_EMATCH_CANID
          To compile this code as a module, choose M here: the
          module will be called em_canid.
 
+config NET_EMATCH_IPSET
+       tristate "IPset"
+       depends on NET_EMATCH && IP_SET
+       ---help---
+         Say Y here if you want to be able to classify packets based on
+         ipset membership.
+
+         To compile this code as a module, choose M here: the
+         module will be called em_ipset.
+
 config NET_CLS_ACT
        bool "Actions"
        ---help---

diff --git a/net/sched/Makefile b/net/sched/Makefile
index bcada75..978cbf0 100644 (file)
--- a/net/sched/Makefile
+++ b/net/sched/Makefile
@@ -56,3 +56,4 @@ obj-$(CONFIG_NET_EMATCH_U32)  += em_u32.o
 obj-$(CONFIG_NET_EMATCH_META)  += em_meta.o
 obj-$(CONFIG_NET_EMATCH_TEXT)  += em_text.o
 obj-$(CONFIG_NET_EMATCH_CANID) += em_canid.o
+obj-$(CONFIG_NET_EMATCH_IPSET) += em_ipset.o

diff --git a/net/sched/em_ipset.c b/net/sched/em_ipset.c
new file mode 100644 (file)
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);