netfilter: nft: add queue module

This patch adds a new nft module named "nft_queue" which provides
a new nftables expression that allows you to enqueue packets to
userspace via the nfnetlink_queue subsystem. It provides the same
level of functionality as NFQUEUE and it shares some code with it.

Signed-off-by: Eric Leblond <eric@regit.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
index fbfd229a8e99e123108c6fc80dd962df683e5622..256d36b1b94a56291aa482c25ef45ca65334258a 100644 (file)
--- a/include/uapi/linux/netfilter/nf_tables.h
+++ b/include/uapi/linux/netfilter/nf_tables.h
@@ -657,6 +657,26 @@ enum nft_log_attributes {
 };
 #define NFTA_LOG_MAX           (__NFTA_LOG_MAX - 1)
 
+/**
+ * enum nft_queue_attributes - nf_tables queue expression netlink attributes
+ *
+ * @NFTA_QUEUE_NUM: netlink queue to send messages to (NLA_U16)
+ * @NFTA_QUEUE_TOTAL: number of queues to load balance packets on (NLA_U16)
+ * @NFTA_QUEUE_FLAGS: various flags (NLA_U16)
+ */
+enum nft_queue_attributes {
+       NFTA_QUEUE_UNSPEC,
+       NFTA_QUEUE_NUM,
+       NFTA_QUEUE_TOTAL,
+       NFTA_QUEUE_FLAGS,
+       __NFTA_QUEUE_MAX
+};
+#define NFTA_QUEUE_MAX         (__NFTA_QUEUE_MAX - 1)
+
+#define NFT_QUEUE_FLAG_BYPASS          0x01 /* for compatibility with v2 */
+#define NFT_QUEUE_FLAG_CPU_FANOUT      0x02 /* use current CPU (no hashing) */
+#define NFT_QUEUE_FLAG_MASK            0x03
+
 /**
  * enum nft_reject_types - nf_tables reject expression reject types
  *

diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig
index 48acec17e27a1524ced30bd86ad865f147ef3a3e..4371c9819d972c11a41775dfbffa6b300947014f 100644 (file)
--- a/net/netfilter/Kconfig
+++ b/net/netfilter/Kconfig
@@ -456,6 +456,15 @@ config NFT_NAT
        depends on NF_NAT
        tristate "Netfilter nf_tables nat module"
 
+config NFT_QUEUE
+       depends on NF_TABLES
+       depends on NETFILTER_XTABLES
+       depends on NETFILTER_NETLINK_QUEUE
+       tristate "Netfilter nf_tables queue module"
+       help
+         This is required if you intend to use the userspace queueing
+         infrastructure (also known as NFQUEUE) from nftables.
+
 config NFT_COMPAT
        depends on NF_TABLES
        depends on NETFILTER_XTABLES

diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile
index 394483b2c193c53fb08dd98591969db0fa995fa8..e7637463226e843d91edfdb4c4282017167e7527 100644 (file)
--- a/net/netfilter/Makefile
+++ b/net/netfilter/Makefile
@@ -76,6 +76,7 @@ obj-$(CONFIG_NFT_META)                += nft_meta.o
 obj-$(CONFIG_NFT_CT)           += nft_ct.o
 obj-$(CONFIG_NFT_LIMIT)                += nft_limit.o
 obj-$(CONFIG_NFT_NAT)          += nft_nat.o
+obj-$(CONFIG_NFT_QUEUE)                += nft_queue.o
 #nf_tables-objs                        += nft_meta_target.o
 obj-$(CONFIG_NFT_RBTREE)       += nft_rbtree.o
 obj-$(CONFIG_NFT_HASH)         += nft_hash.o

diff --git a/net/netfilter/nft_queue.c b/net/netfilter/nft_queue.c
new file mode 100644 (file)
index 0000000..cbea473
--- /dev/null
+++ b/net/netfilter/nft_queue.c
@@ -0,0 +1,134 @@
+/*
+ * Copyright (c) 2013 Eric Leblond <eric@regit.org>
+ *
+ * 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.
+ *
+ * Development of this code partly funded by OISF
+ * (http://www.openinfosecfoundation.org/)
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/netlink.h>
+#include <linux/jhash.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter/nf_tables.h>
+#include <net/netfilter/nf_tables.h>
+#include <net/netfilter/nf_queue.h>
+
+static u32 jhash_initval __read_mostly;
+
+struct nft_queue {
+       u16     queuenum;
+       u16     queues_total;
+       u16     flags;
+       u8      family;
+};
+
+static void nft_queue_eval(const struct nft_expr *expr,
+                          struct nft_data data[NFT_REG_MAX + 1],
+                          const struct nft_pktinfo *pkt)
+{
+       struct nft_queue *priv = nft_expr_priv(expr);
+       u32 queue = priv->queuenum;
+       u32 ret;
+
+       if (priv->queues_total > 1) {
+               if (priv->flags & NFT_QUEUE_FLAG_CPU_FANOUT) {
+                       int cpu = smp_processor_id();
+
+                       queue = priv->queuenum + cpu % priv->queues_total;
+               } else {
+                       queue = nfqueue_hash(pkt->skb, queue,
+                                            priv->queues_total, priv->family,
+                                            jhash_initval);
+               }
+       }
+
+       ret = NF_QUEUE_NR(queue);
+       if (priv->flags & NFT_QUEUE_FLAG_BYPASS)
+               ret |= NF_VERDICT_FLAG_QUEUE_BYPASS;
+
+       data[NFT_REG_VERDICT].verdict = ret;
+}
+
+static const struct nla_policy nft_queue_policy[NFTA_QUEUE_MAX + 1] = {
+       [NFTA_QUEUE_NUM]        = { .type = NLA_U16 },
+       [NFTA_QUEUE_TOTAL]      = { .type = NLA_U16 },
+       [NFTA_QUEUE_FLAGS]      = { .type = NLA_U16 },
+};
+
+static int nft_queue_init(const struct nft_ctx *ctx,
+                          const struct nft_expr *expr,
+                          const struct nlattr * const tb[])
+{
+       struct nft_queue *priv = nft_expr_priv(expr);
+
+       if (tb[NFTA_QUEUE_NUM] == NULL)
+               return -EINVAL;
+
+       init_hashrandom(&jhash_initval);
+       priv->family = ctx->afi->family;
+       priv->queuenum = ntohs(nla_get_be16(tb[NFTA_QUEUE_NUM]));
+
+       if (tb[NFTA_QUEUE_TOTAL] != NULL)
+               priv->queues_total = ntohs(nla_get_be16(tb[NFTA_QUEUE_TOTAL]));
+       if (tb[NFTA_QUEUE_FLAGS] != NULL) {
+               priv->flags = ntohs(nla_get_be16(tb[NFTA_QUEUE_FLAGS]));
+               if (priv->flags & ~NFT_QUEUE_FLAG_MASK)
+                       return -EINVAL;
+       }
+       return 0;
+}
+
+static int nft_queue_dump(struct sk_buff *skb, const struct nft_expr *expr)
+{
+       const struct nft_queue *priv = nft_expr_priv(expr);
+
+       if (nla_put_be16(skb, NFTA_QUEUE_NUM, htons(priv->queuenum)) ||
+           nla_put_be16(skb, NFTA_QUEUE_TOTAL, htons(priv->queues_total)) ||
+           nla_put_be16(skb, NFTA_QUEUE_FLAGS, htons(priv->flags)))
+               goto nla_put_failure;
+
+       return 0;
+
+nla_put_failure:
+       return -1;
+}
+
+static struct nft_expr_type nft_queue_type;
+static const struct nft_expr_ops nft_queue_ops = {
+       .type           = &nft_queue_type,
+       .size           = NFT_EXPR_SIZE(sizeof(struct nft_queue)),
+       .eval           = nft_queue_eval,
+       .init           = nft_queue_init,
+       .dump           = nft_queue_dump,
+};
+
+static struct nft_expr_type nft_queue_type __read_mostly = {
+       .name           = "queue",
+       .ops            = &nft_queue_ops,
+       .policy         = nft_queue_policy,
+       .maxattr        = NFTA_QUEUE_MAX,
+       .owner          = THIS_MODULE,
+};
+
+static int __init nft_queue_module_init(void)
+{
+       return nft_register_expr(&nft_queue_type);
+}
+
+static void __exit nft_queue_module_exit(void)
+{
+       nft_unregister_expr(&nft_queue_type);
+}
+
+module_init(nft_queue_module_init);
+module_exit(nft_queue_module_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Eric Leblond <eric@regit.org>");
+MODULE_ALIAS_NFT_EXPR("queue");