This module is a port of iptables CT target. It allows
user to setup connection tracking for selected packets.
The context is not containing information about layer 4
so it is necessary to ask to userspace explicitely for
which layer 4 protocol the connection template has to be
created. This is the reason why the NFTA_CT_SET_PROTO
field has been introduced.
Signed-off-by: Eric Leblond <eric@xxxxxxxxx>
---
include/uapi/linux/netfilter/nf_tables.h | 36 +++++
net/netfilter/Kconfig | 5 +
net/netfilter/Makefile | 1 +
net/netfilter/nft_ct_set.c | 262 +++++++++++++++++++++++++++++++
4 files changed, 304 insertions(+)
create mode 100644 net/netfilter/nft_ct_set.c
diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
index aa86a152..96bde79 100644
--- a/include/uapi/linux/netfilter/nf_tables.h
+++ b/include/uapi/linux/netfilter/nf_tables.h
@@ -707,6 +707,42 @@ enum nft_reject_attributes {
#define NFTA_REJECT_MAX (__NFTA_REJECT_MAX - 1)
/**
+ * enum nft_ct_set_attributes - nf_tables ct_set expression netlink attributes
+ *
+ * @NFTA_CT_SET_PROTO: layer 4 protocol
+ * @NFTA_CT_SET_FLAGS: flags for connection as NOTRACK for example
+ * @NFTA_CT_SET_HELPER: protocol helper to link with matching connections
+ * @NFTA_CT_SET_CTEVENTS: only generate the specified conntrack events
+ * @NFTA_CT_SET_EXPEVENTS: only generate the specified expectation events
+ * @NFTA_CT_SET_ZONEID: assign packet to sone id
+ * @NFTA_CT_SET_TIMEOUT: use timeout policy for the connection
+ *
+ */
+enum nft_ct_set_attributes {
+ NFTA_CT_SET_UNSPEC,
+ NFTA_CT_SET_PROTO,
+ NFTA_CT_SET_FLAGS,
+ NFTA_CT_SET_HELPER,
+ NFTA_CT_SET_CTEVENTS,
+ NFTA_CT_SET_EXPEVENTS,
+ NFTA_CT_SET_ZONEID,
+ NFTA_CT_SET_TIMEOUT,
+ __NFTA_CT_SET_MAX
+};
+#define NFTA_CT_SET_MAX (__NFTA_CT_SET_MAX - 1)
+
+/**
+ * enum nft_ct_set_flags - nf_tables ct_set flags
+ *
+ * @NFT_CT_SET_F_NOTRACK: do not track this connection
+ */
+enum nft_ct_set_flags {
+
+enum nft_ct_set_flags {
+ NFT_CT_SET_F_NOTRACK = 0x1,
+};
+
+/**
* enum nft_nat_types - nf_tables nat expression NAT types
*
* @NFT_NAT_SNAT: source NAT
diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig
index a1dec61..448c389 100644
--- a/net/netfilter/Kconfig
+++ b/net/netfilter/Kconfig
@@ -430,6 +430,11 @@ config NFT_CT
depends on NF_CONNTRACK
tristate "Netfilter nf_tables conntrack module"
+config NFT_CT_SET
+ depends on NF_TABLES
+ depends on NF_CONNTRACK
+ tristate "Netfilter nf_tables conntrack setup module"
+
config NFT_RBTREE
depends on NF_TABLES
tristate "Netfilter nf_tables rbtree set module"
diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile
index 39e4a7b..f50c501 100644
--- a/net/netfilter/Makefile
+++ b/net/netfilter/Makefile
@@ -74,6 +74,7 @@ obj-$(CONFIG_NFT_COMPAT) += nft_compat.o
obj-$(CONFIG_NFT_EXTHDR) += nft_exthdr.o
obj-$(CONFIG_NFT_META) += nft_meta.o
obj-$(CONFIG_NFT_CT) += nft_ct.o
+obj-$(CONFIG_NFT_CT_SET) += nft_ct_set.o
obj-$(CONFIG_NFT_LIMIT) += nft_limit.o
obj-$(CONFIG_NFT_NAT) += nft_nat.o
obj-$(CONFIG_NFT_QUEUE) += nft_queue.o
diff --git a/net/netfilter/nft_ct_set.c b/net/netfilter/nft_ct_set.c
new file mode 100644
index 0000000..93e862d
--- /dev/null
+++ b/net/netfilter/nft_ct_set.c
@@ -0,0 +1,262 @@
+/*
+ * Copyright (c) 2014 Eric Leblond <eric@xxxxxxxxx>
+ *
+ * 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/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/netlink.h>
+#include <linux/rculist_nulls.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter/nf_tables.h>
+#include <net/netfilter/nf_tables.h>
+#include <net/netfilter/nf_conntrack.h>
+#include <net/netfilter/nf_ct_set.h>
+
+struct nft_ct_set {
+ __u16 flags;
+ __u16 zoneid;
+ __u32 ct_events;
+ __u32 exp_events;
+ char *helper;
+ char *timeout;
+
+ /* Used internally by the kernel */
+ struct nf_conn *ct __attribute__((aligned(8)));
+ __u16 proto;
+};
+
+static void nft_ct_set_eval(const struct nft_expr *expr,
+ struct nft_data data[NFT_REG_MAX + 1],
+ const struct nft_pktinfo *pkt)
+{
+ struct nft_ct_set *priv = nft_expr_priv(expr);
+ struct nf_conn *ct;
+
+ if (pkt->skb->nfct != NULL)
+ return;
+
+ if (priv->flags & NFT_CT_SET_F_NOTRACK)
+ ct = nf_ct_untracked_get();
+ else
+ ct = priv->ct;
+
+ atomic_inc(&ct->ct_general.use);
+ pkt->skb->nfct = &ct->ct_general;
+ pkt->skb->nfctinfo = IP_CT_NEW;
+}
+
+static const struct nla_policy nft_ct_set_policy[NFTA_CT_SET_MAX + 1] = {
+ [NFTA_CT_SET_FLAGS] = { .type = NLA_U16 },
+ [NFTA_CT_SET_HELPER] = { .type = NLA_STRING },
+ [NFTA_CT_SET_CTEVENTS] = { .type = NLA_U32 },
+ [NFTA_CT_SET_EXPEVENTS] = { .type = NLA_U32 },
+ [NFTA_CT_SET_ZONEID] = { .type = NLA_U16 },
+ [NFTA_CT_SET_TIMEOUT] = { .type = NLA_STRING },
+};
+
+static int nft_ct_set_init(const struct nft_ctx *ctx,
+ const struct nft_expr *expr,
+ const struct nlattr * const tb[])
+{
+ struct nft_ct_set *priv = nft_expr_priv(expr);
+ const struct nlattr *nla;
+ struct nf_conntrack_tuple t;
+ struct nf_conn *ct;
+ int ret = -EOPNOTSUPP;
+
+
+ if (tb[NFTA_CT_SET_PROTO] != NULL)
+ priv->proto = ntohs(nla_get_be16(tb[NFTA_CT_SET_PROTO]));
+ else
+ return -EINVAL;
+
+ if (tb[NFTA_CT_SET_FLAGS] != NULL)
+ priv->flags = ntohs(nla_get_be16(tb[NFTA_CT_SET_FLAGS]));
+
+ if (priv->flags & NFT_CT_SET_F_NOTRACK) {
+ ct = NULL;
+ goto out;
+ }
+
+ if (tb[NFTA_CT_SET_HELPER] != NULL) {
+ nla = tb[NFTA_CT_SET_HELPER];
+ priv->helper = kmalloc(nla_len(nla) + 1, GFP_KERNEL);
+ if (priv->helper == NULL)
+ return -ENOMEM;
+ nla_strlcpy(priv->helper, nla, nla_len(nla) + 1);
+ }
+
+ if (tb[NFTA_CT_SET_CTEVENTS] != NULL)
+ priv->ct_events = ntohl(nla_get_be32(tb[NFTA_CT_SET_CTEVENTS]));
+
+ if (tb[NFTA_CT_SET_EXPEVENTS] != NULL)
+ priv->exp_events =
+ ntohl(nla_get_be32(tb[NFTA_CT_SET_EXPEVENTS]));
+
+ if (tb[NFTA_CT_SET_ZONEID] != NULL) {
+#ifndef CONFIG_NF_CONNTRACK_ZONES
+ goto err1;
+#endif
+ priv->zoneid = ntohs(nla_get_be16(tb[NFTA_CT_SET_ZONEID]));
+ }
+
+ if (tb[NFTA_CT_SET_TIMEOUT] != NULL) {
+#ifndef CONFIG_NF_CONNTRACK_TIMEOUT
+ goto err1;
+#endif
+ nla = tb[NFTA_CT_SET_TIMEOUT];
+ priv->timeout = kmalloc(nla_len(nla) + 1, GFP_KERNEL);
+ if (priv->timeout == NULL) {
+ ret = -ENOMEM;
+ goto err1;
+ }
+ nla_strlcpy(priv->timeout, nla, nla_len(nla) + 1);
+ }
+
+ ret = nf_ct_l3proto_try_module_get(ctx->afi->family);
+ if (ret < 0)
+ goto err1;
+
+ memset(&t, 0, sizeof(t));
+ ct = nf_conntrack_alloc(ctx->net, priv->zoneid, &t, &t, GFP_KERNEL);
+ ret = PTR_ERR(ct);
+ if (IS_ERR(ct))
+ goto err2;
+
+ ret = 0;
+ if ((priv->ct_events || priv->exp_events) &&
+ !nf_ct_ecache_ext_add(ct, priv->ct_events, priv->exp_events,
+ GFP_KERNEL)) {
+ ret = -EINVAL;
+ goto err3;
+ }
+
+ if (priv->helper) {
+ ret = nf_ct_set_helper(ct, priv->helper, priv->proto,
+ ctx->afi->family);
+ if (ret < 0)
+ goto err3;
+ }
+
+ if (priv->timeout) {
+ ret = nf_ct_set_timeout(ct, priv->proto, ctx->afi->family,
+ priv->timeout);
+ if (ret < 0)
+ goto err3;
+ }
+
+ __set_bit(IPS_TEMPLATE_BIT, &ct->status);
+ __set_bit(IPS_CONFIRMED_BIT, &ct->status);
+
+ /* Overload tuple linked list to put us in template list. */
+ hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
+ &ctx->net->ct.tmpl);
+
+out:
+ priv->ct = ct;
+ return 0;
+
+err3:
+ nf_conntrack_free(ct);
+err2:
+ nf_ct_l3proto_module_put(ctx->afi->family);
+
+err1:
+ if (priv->helper)
+ kfree(priv->helper);
+ if (priv->timeout)
+ kfree(priv->timeout);
+ return ret;
+}
+
+static int nft_ct_set_dump(struct sk_buff *skb, const struct nft_expr *expr)
+{
+ const struct nft_ct_set *priv = nft_expr_priv(expr);
+
+ if (nla_put_be16(skb, NFTA_CT_SET_FLAGS, htons(priv->flags)) ||
+ nla_put_be16(skb, NFTA_CT_SET_ZONEID, htons(priv->zoneid)) ||
+ nla_put_be16(skb, NFTA_CT_SET_PROTO, htons(priv->proto)) ||
+ nla_put_be32(skb, NFTA_CT_SET_CTEVENTS, htons(priv->ct_events)) ||
+ nla_put_be32(skb, NFTA_CT_SET_EXPEVENTS, htons(priv->exp_events)))
+ goto nla_put_failure;
+ if (priv->helper)
+ if (nla_put_string(skb, NFTA_CT_SET_HELPER, priv->helper))
+ goto nla_put_failure;
+ if (priv->timeout)
+ if (nla_put_string(skb, NFTA_CT_SET_TIMEOUT, priv->timeout))
+ goto nla_put_failure;
+
+ return 0;
+
+nla_put_failure:
+ return -1;
+}
+
+
+static void nft_ct_set_destroy(const struct nft_expr *expr) {
+ struct nft_ct_set *priv = nft_expr_priv(expr);
+ struct nf_conn_help *help;
+ struct nf_conn *ct = NULL;
+
+ if (priv->helper)
+ kfree(priv->helper);
+
+ if (priv->timeout)
+ kfree(priv->timeout);
+
+ ct = priv->ct;
+ if (ct) {
+ help = nfct_help(ct);
+ if (help)
+ module_put(help->helper->me);
+
+ /* FIXME */
+#if 0
+ nf_ct_l3proto_module_put(par->family);
+#endif
+
+ nf_ct_destroy_timeout(ct);
+ nf_ct_put(priv->ct);
+ }
+}
+
+static struct nft_expr_type nft_ct_set_type;
+static const struct nft_expr_ops nft_ct_set_ops = {
+ .type = &nft_ct_set_type,
+ .size = NFT_EXPR_SIZE(sizeof(struct nft_ct_set)),
+ .eval = nft_ct_set_eval,
+ .init = nft_ct_set_init,
+ .dump = nft_ct_set_dump,
+ .destroy = nft_ct_set_destroy,
+};
+
+static struct nft_expr_type nft_ct_set_type __read_mostly = {
+ .name = "ct_set",
+ .ops = &nft_ct_set_ops,
+ .policy = nft_ct_set_policy,
+ .maxattr = NFTA_CT_SET_MAX,
+ .owner = THIS_MODULE,
+};
+
+static int __init nft_ct_set_module_init(void)
+{
+ return nft_register_expr(&nft_ct_set_type);
+}
+
+static void __exit nft_ct_set_module_exit(void)
+{
+ nft_unregister_expr(&nft_ct_set_type);
+}
+
+module_init(nft_ct_set_module_init);
+module_exit(nft_ct_set_module_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Eric Leblond <eric@xxxxxxxxx>");
+MODULE_ALIAS_NFT_EXPR("ct_set");
--
1.8.5.2
--
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