netfilter: nf_tables: add nft_dup expression

This new expression uses the nf_dup engine to clone packets to a given gateway.
Unlike xt_TEE, we use an index to indicate output interface which should be
fine at this stage.

Moreover, change to the preemtion-safe this_cpu_read(nf_skb_duplicated) from
nf_dup_ipv{4,6} to silence a lockdep splat.

Based on the original tee expression from Arturo Borrero Gonzalez, although
this patch has diverted quite a bit from this initial effort due to the
change to support maps.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/include/net/netfilter/nft_dup.h b/include/net/netfilter/nft_dup.h
new file mode 100644 (file)
index 0000000..6b84cf6
--- /dev/null
+++ b/include/net/netfilter/nft_dup.h
@@ -0,0 +1,9 @@
+#ifndef _NFT_DUP_H_
+#define _NFT_DUP_H_
+
+struct nft_dup_inet {
+       enum nft_registers      sreg_addr:8;
+       enum nft_registers      sreg_dev:8;
+};
+
+#endif /* _NFT_DUP_H_ */

diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
index a99e6a9971408014514c21cc338df70ea5421f34..2ef35f2c9bdaf4be1ab02d5c7699eec13f53ade3 100644 (file)
--- a/include/uapi/linux/netfilter/nf_tables.h
+++ b/include/uapi/linux/netfilter/nf_tables.h
@@ -935,6 +935,20 @@ enum nft_redir_attributes {
 };
 #define NFTA_REDIR_MAX         (__NFTA_REDIR_MAX - 1)
 
+/**
+ * enum nft_dup_attributes - nf_tables dup expression netlink attributes
+ *
+ * @NFTA_DUP_SREG_ADDR: source register of address (NLA_U32: nft_registers)
+ * @NFTA_DUP_SREG_DEV: source register of output interface (NLA_U32: nft_register)
+ */
+enum nft_dup_attributes {
+       NFTA_DUP_UNSPEC,
+       NFTA_DUP_SREG_ADDR,
+       NFTA_DUP_SREG_DEV,
+       __NFTA_DUP_MAX
+};
+#define NFTA_DUP_MAX           (__NFTA_DUP_MAX - 1)
+
 /**
  * enum nft_gen_attributes - nf_tables ruleset generation attributes
  *

diff --git a/net/ipv4/netfilter/Kconfig b/net/ipv4/netfilter/Kconfig
index 0142ea259d7d7aeec969539a9ee64d5af2c97ff2..690d27d3f2f90d99612de8ed4a32dec0596a680a 100644 (file)
--- a/net/ipv4/netfilter/Kconfig
+++ b/net/ipv4/netfilter/Kconfig
@@ -58,6 +58,12 @@ config NFT_REJECT_IPV4
        default NFT_REJECT
        tristate
 
+config NFT_DUP_IPV4
+       tristate "IPv4 nf_tables packet duplication support"
+       select NF_DUP_IPV4
+       help
+         This module enables IPv4 packet duplication support for nf_tables.
+
 endif # NF_TABLES_IPV4
 
 config NF_TABLES_ARP

diff --git a/net/ipv4/netfilter/Makefile b/net/ipv4/netfilter/Makefile
index 9136ffc2d4740cb8a005102312b15f9c7df340c5..87b073da14c928df176e7f4163e5301edcafdd89 100644 (file)
--- a/net/ipv4/netfilter/Makefile
+++ b/net/ipv4/netfilter/Makefile
@@ -41,6 +41,7 @@ obj-$(CONFIG_NFT_CHAIN_NAT_IPV4) += nft_chain_nat_ipv4.o
 obj-$(CONFIG_NFT_REJECT_IPV4) += nft_reject_ipv4.o
 obj-$(CONFIG_NFT_MASQ_IPV4) += nft_masq_ipv4.o
 obj-$(CONFIG_NFT_REDIR_IPV4) += nft_redir_ipv4.o
+obj-$(CONFIG_NFT_DUP_IPV4) += nft_dup_ipv4.o
 obj-$(CONFIG_NF_TABLES_ARP) += nf_tables_arp.o
 
 # generic IP tables 

diff --git a/net/ipv4/netfilter/nf_dup_ipv4.c b/net/ipv4/netfilter/nf_dup_ipv4.c
index eff85ab3f47dfd99f63119b8d47d57c8bd49159a..b5bb37564b0e5094534a2acef57f7f5a31a3b75b 100644 (file)
--- a/net/ipv4/netfilter/nf_dup_ipv4.c
+++ b/net/ipv4/netfilter/nf_dup_ipv4.c
@@ -69,7 +69,7 @@ void nf_dup_ipv4(struct sk_buff *skb, unsigned int hooknum,
 {
        struct iphdr *iph;
 
-       if (__this_cpu_read(nf_skb_duplicated))
+       if (this_cpu_read(nf_skb_duplicated))
                return;
        /*
         * Copy the skb, and route the copy. Will later return %XT_CONTINUE for

diff --git a/net/ipv4/netfilter/nft_dup_ipv4.c b/net/ipv4/netfilter/nft_dup_ipv4.c
new file mode 100644 (file)
index 0000000..25419fb
--- /dev/null
+++ b/net/ipv4/netfilter/nft_dup_ipv4.c
@@ -0,0 +1,110 @@
+/*
+ * Copyright (c) 2015 Pablo Neira Ayuso <pablo@netfilter.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.
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/netlink.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter/nf_tables.h>
+#include <net/netfilter/nf_tables.h>
+#include <net/netfilter/ipv4/nf_dup_ipv4.h>
+
+struct nft_dup_ipv4 {
+       enum nft_registers      sreg_addr:8;
+       enum nft_registers      sreg_dev:8;
+};
+
+static void nft_dup_ipv4_eval(const struct nft_expr *expr,
+                             struct nft_regs *regs,
+                             const struct nft_pktinfo *pkt)
+{
+       struct nft_dup_ipv4 *priv = nft_expr_priv(expr);
+       struct in_addr gw = {
+               .s_addr = regs->data[priv->sreg_addr],
+       };
+       int oif = regs->data[priv->sreg_dev];
+
+       nf_dup_ipv4(pkt->skb, pkt->ops->hooknum, &gw, oif);
+}
+
+static int nft_dup_ipv4_init(const struct nft_ctx *ctx,
+                            const struct nft_expr *expr,
+                            const struct nlattr * const tb[])
+{
+       struct nft_dup_ipv4 *priv = nft_expr_priv(expr);
+       int err;
+
+       if (tb[NFTA_DUP_SREG_ADDR] == NULL)
+               return -EINVAL;
+
+       priv->sreg_addr = nft_parse_register(tb[NFTA_DUP_SREG_ADDR]);
+       err = nft_validate_register_load(priv->sreg_addr, sizeof(struct in_addr));
+       if (err < 0)
+               return err;
+
+       if (tb[NFTA_DUP_SREG_DEV] != NULL) {
+               priv->sreg_dev = nft_parse_register(tb[NFTA_DUP_SREG_DEV]);
+               return nft_validate_register_load(priv->sreg_dev, sizeof(int));
+       }
+       return 0;
+}
+
+static int nft_dup_ipv4_dump(struct sk_buff *skb, const struct nft_expr *expr)
+{
+       struct nft_dup_ipv4 *priv = nft_expr_priv(expr);
+
+       if (nft_dump_register(skb, NFTA_DUP_SREG_ADDR, priv->sreg_addr) ||
+           nft_dump_register(skb, NFTA_DUP_SREG_DEV, priv->sreg_dev))
+               goto nla_put_failure;
+
+       return 0;
+
+nla_put_failure:
+       return -1;
+}
+
+static struct nft_expr_type nft_dup_ipv4_type;
+static const struct nft_expr_ops nft_dup_ipv4_ops = {
+       .type           = &nft_dup_ipv4_type,
+       .size           = NFT_EXPR_SIZE(sizeof(struct nft_dup_ipv4)),
+       .eval           = nft_dup_ipv4_eval,
+       .init           = nft_dup_ipv4_init,
+       .dump           = nft_dup_ipv4_dump,
+};
+
+static const struct nla_policy nft_dup_ipv4_policy[NFTA_DUP_MAX + 1] = {
+       [NFTA_DUP_SREG_ADDR]    = { .type = NLA_U32 },
+       [NFTA_DUP_SREG_DEV]     = { .type = NLA_U32 },
+};
+
+static struct nft_expr_type nft_dup_ipv4_type __read_mostly = {
+       .family         = NFPROTO_IPV4,
+       .name           = "dup",
+       .ops            = &nft_dup_ipv4_ops,
+       .policy         = nft_dup_ipv4_policy,
+       .maxattr        = NFTA_DUP_MAX,
+       .owner          = THIS_MODULE,
+};
+
+static int __init nft_dup_ipv4_module_init(void)
+{
+       return nft_register_expr(&nft_dup_ipv4_type);
+}
+
+static void __exit nft_dup_ipv4_module_exit(void)
+{
+       nft_unregister_expr(&nft_dup_ipv4_type);
+}
+
+module_init(nft_dup_ipv4_module_init);
+module_exit(nft_dup_ipv4_module_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
+MODULE_ALIAS_NFT_AF_EXPR(AF_INET, "dup");

diff --git a/net/ipv6/netfilter/Kconfig b/net/ipv6/netfilter/Kconfig
index 298daf30d8575ed19eb506efd0627abb49fced57..96833e4b31939a191eaf7de297ac438d4aa41fa4 100644 (file)
--- a/net/ipv6/netfilter/Kconfig
+++ b/net/ipv6/netfilter/Kconfig
@@ -47,6 +47,12 @@ config NFT_REJECT_IPV6
        default NFT_REJECT
        tristate
 
+config NFT_DUP_IPV6
+       tristate "IPv6 nf_tables packet duplication support"
+       select NF_DUP_IPV6
+       help
+         This module enables IPv6 packet duplication support for nf_tables.
+
 endif # NF_TABLES_IPV6
 endif # NF_TABLES
 

diff --git a/net/ipv6/netfilter/Makefile b/net/ipv6/netfilter/Makefile
index dc6c732f98caa9810491b070257cb2836233103d..b4f7d0b4e2afc630f7a5be2ae949dff676dc5985 100644 (file)
--- a/net/ipv6/netfilter/Makefile
+++ b/net/ipv6/netfilter/Makefile
@@ -39,6 +39,7 @@ obj-$(CONFIG_NFT_CHAIN_NAT_IPV6) += nft_chain_nat_ipv6.o
 obj-$(CONFIG_NFT_REJECT_IPV6) += nft_reject_ipv6.o
 obj-$(CONFIG_NFT_MASQ_IPV6) += nft_masq_ipv6.o
 obj-$(CONFIG_NFT_REDIR_IPV6) += nft_redir_ipv6.o
+obj-$(CONFIG_NFT_DUP_IPV6) += nft_dup_ipv6.o
 
 # matches
 obj-$(CONFIG_IP6_NF_MATCH_AH) += ip6t_ah.o

diff --git a/net/ipv6/netfilter/nf_dup_ipv6.c b/net/ipv6/netfilter/nf_dup_ipv6.c
index 399fdda18447079e2463ec868d847b66626bcc57..d8ab654080b48db998e3255db2a482a83414ffaf 100644 (file)
--- a/net/ipv6/netfilter/nf_dup_ipv6.c
+++ b/net/ipv6/netfilter/nf_dup_ipv6.c
@@ -63,7 +63,7 @@ static bool nf_dup_ipv6_route(struct sk_buff *skb, const struct in6_addr *gw,
 void nf_dup_ipv6(struct sk_buff *skb, unsigned int hooknum,
                 const struct in6_addr *gw, int oif)
 {
-       if (__this_cpu_read(nf_skb_duplicated))
+       if (this_cpu_read(nf_skb_duplicated))
                return;
        skb = pskb_copy(skb, GFP_ATOMIC);
        if (skb == NULL)

diff --git a/net/ipv6/netfilter/nft_dup_ipv6.c b/net/ipv6/netfilter/nft_dup_ipv6.c
new file mode 100644 (file)
index 0000000..0eaa4f6
--- /dev/null
+++ b/net/ipv6/netfilter/nft_dup_ipv6.c
@@ -0,0 +1,108 @@
+/*
+ * Copyright (c) 2015 Pablo Neira Ayuso <pablo@netfilter.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.
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/netlink.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter/nf_tables.h>
+#include <net/netfilter/nf_tables.h>
+#include <net/netfilter/ipv6/nf_dup_ipv6.h>
+
+struct nft_dup_ipv6 {
+       enum nft_registers      sreg_addr:8;
+       enum nft_registers      sreg_dev:8;
+};
+
+static void nft_dup_ipv6_eval(const struct nft_expr *expr,
+                             struct nft_regs *regs,
+                             const struct nft_pktinfo *pkt)
+{
+       struct nft_dup_ipv6 *priv = nft_expr_priv(expr);
+       struct in6_addr *gw = (struct in6_addr *)&regs->data[priv->sreg_addr];
+       int oif = regs->data[priv->sreg_dev];
+
+       nf_dup_ipv6(pkt->skb, pkt->ops->hooknum, gw, oif);
+}
+
+static int nft_dup_ipv6_init(const struct nft_ctx *ctx,
+                            const struct nft_expr *expr,
+                            const struct nlattr * const tb[])
+{
+       struct nft_dup_ipv6 *priv = nft_expr_priv(expr);
+       int err;
+
+       if (tb[NFTA_DUP_SREG_ADDR] == NULL)
+               return -EINVAL;
+
+       priv->sreg_addr = nft_parse_register(tb[NFTA_DUP_SREG_ADDR]);
+       err = nft_validate_register_load(priv->sreg_addr, sizeof(struct in6_addr));
+       if (err < 0)
+               return err;
+
+       if (tb[NFTA_DUP_SREG_DEV] != NULL) {
+               priv->sreg_dev = nft_parse_register(tb[NFTA_DUP_SREG_DEV]);
+               return nft_validate_register_load(priv->sreg_dev, sizeof(int));
+       }
+       return 0;
+}
+
+static int nft_dup_ipv6_dump(struct sk_buff *skb, const struct nft_expr *expr)
+{
+       struct nft_dup_ipv6 *priv = nft_expr_priv(expr);
+
+       if (nft_dump_register(skb, NFTA_DUP_SREG_ADDR, priv->sreg_addr) ||
+           nft_dump_register(skb, NFTA_DUP_SREG_DEV, priv->sreg_dev))
+               goto nla_put_failure;
+
+       return 0;
+
+nla_put_failure:
+       return -1;
+}
+
+static struct nft_expr_type nft_dup_ipv6_type;
+static const struct nft_expr_ops nft_dup_ipv6_ops = {
+       .type           = &nft_dup_ipv6_type,
+       .size           = NFT_EXPR_SIZE(sizeof(struct nft_dup_ipv6)),
+       .eval           = nft_dup_ipv6_eval,
+       .init           = nft_dup_ipv6_init,
+       .dump           = nft_dup_ipv6_dump,
+};
+
+static const struct nla_policy nft_dup_ipv6_policy[NFTA_DUP_MAX + 1] = {
+       [NFTA_DUP_SREG_ADDR]    = { .type = NLA_U32 },
+       [NFTA_DUP_SREG_DEV]     = { .type = NLA_U32 },
+};
+
+static struct nft_expr_type nft_dup_ipv6_type __read_mostly = {
+       .family         = NFPROTO_IPV6,
+       .name           = "dup",
+       .ops            = &nft_dup_ipv6_ops,
+       .policy         = nft_dup_ipv6_policy,
+       .maxattr        = NFTA_DUP_MAX,
+       .owner          = THIS_MODULE,
+};
+
+static int __init nft_dup_ipv6_module_init(void)
+{
+       return nft_register_expr(&nft_dup_ipv6_type);
+}
+
+static void __exit nft_dup_ipv6_module_exit(void)
+{
+       nft_unregister_expr(&nft_dup_ipv6_type);
+}
+
+module_init(nft_dup_ipv6_module_init);
+module_exit(nft_dup_ipv6_module_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
+MODULE_ALIAS_NFT_AF_EXPR(AF_INET6, "dup");