Now it can only match the transparent flag of an ip/ipv6 socket.
Signed-off-by: Máté Eckl <ecklm94@xxxxxxxxx>
---
include/uapi/linux/netfilter/nf_tables.h | 28 +++++
net/netfilter/Kconfig | 9 ++
net/netfilter/Makefile | 1 +
net/netfilter/nft_socket.c | 143 +++++++++++++++++++++++
4 files changed, 181 insertions(+)
create mode 100644 net/netfilter/nft_socket.c
diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
index 9c71f024f9cc..96ab31539bf6 100644
--- a/include/uapi/linux/netfilter/nf_tables.h
+++ b/include/uapi/linux/netfilter/nf_tables.h
@@ -904,6 +904,34 @@ enum nft_rt_attributes {
};
#define NFTA_RT_MAX (__NFTA_RT_MAX - 1)
+/**
+ * enum nft_socket_attributes - nf_tables socket expression netlink attributes
+ *
+ * @NFTA_SOCKET_KEY: socket key to match
+ * @NFTA_SOCKET_DREG: destination register
+ */
+enum nft_socket_attributes {
+ NFTA_SOCKET_UNSPEC,
+
+ NFTA_SOCKET_KEY,
+ NFTA_SOCKET_DREG,
+
+ __NFTA_SOCKET_MAX
+};
+#define NFTA_SOCKET_MAX (__NFTA_SOCKET_MAX - 1)
+
+/*
+ * enum nft_socket_keys - nf_tables socket expression keys
+ *
+ * @NFT_SOCKET_TRANSPARENT: Value of the IP(V6)_TRANSPARENT socket option_
+ */
+enum nft_socket_keys {
+ NFT_SOCKET_TRANSPARENT,
+
+ __NFT_SOCKET_MAX
+};
+#define NFT_SOCKET_MAX (__NFT_SOCKET_MAX - 1)
+
/**
* enum nft_ct_keys - nf_tables ct expression keys
*
diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig
index 3ec8886850b2..276e1e32f44e 100644
--- a/net/netfilter/Kconfig
+++ b/net/netfilter/Kconfig
@@ -613,6 +613,15 @@ config NFT_FIB_INET
The lookup will be delegated to the IPv4 or IPv6 FIB depending
on the protocol of the packet.
+config NFT_SOCKET
+ tristate "Netfilter nf_tables socket match support"
+ depends on IPV6 || IPV6=n
+ select NF_SOCKET_IPV4
+ select NF_SOCKET_IPV6 if IPV6
+ help
+ This option allows matching for the presence or absence of a
+ corresponding socket and its attributes.
+
if NF_TABLES_NETDEV
config NF_DUP_NETDEV
diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile
index 9b3434360d49..eec169555731 100644
--- a/net/netfilter/Makefile
+++ b/net/netfilter/Makefile
@@ -102,6 +102,7 @@ obj-$(CONFIG_NFT_FIB) += nft_fib.o
obj-$(CONFIG_NFT_FIB_INET) += nft_fib_inet.o
obj-$(CONFIG_NFT_FIB_NETDEV) += nft_fib_netdev.o
obj-$(CONFIG_NF_OSF) += nf_osf.o
+obj-$(CONFIG_NFT_SOCKET) += nft_socket.o
# nf_tables netdev
obj-$(CONFIG_NFT_DUP_NETDEV) += nft_dup_netdev.o
diff --git a/net/netfilter/nft_socket.c b/net/netfilter/nft_socket.c
new file mode 100644
index 000000000000..dd389b37334a
--- /dev/null
+++ b/net/netfilter/nft_socket.c
@@ -0,0 +1,143 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/module.h>
+#include <linux/netfilter/nf_tables.h>
+#include <net/netfilter/nf_tables.h>
+#include <net/netfilter/nf_tables_core.h>
+#include <net/netfilter/nf_socket.h>
+#include <net/inet_sock.h>
+
+struct nft_socket {
+ enum nft_socket_keys key:8;
+ union {
+ enum nft_registers dreg:8;
+ };
+};
+
+static void nft_socket_eval(const struct nft_expr *expr,
+ struct nft_regs *regs,
+ const struct nft_pktinfo *pkt)
+{
+ const struct nft_socket *priv = nft_expr_priv(expr);
+ struct sk_buff *skb = pkt->skb;
+ struct sock *sk = skb->sk;
+ u32 *dest = ®s->data[priv->dreg];
+
+ if (!sk)
+ switch(nft_pf(pkt)) {
+ case NFPROTO_IPV4:
+ sk = nf_sk_lookup_slow_v4(nft_net(pkt), skb, nft_in(pkt));
+ break;
+#if IS_ENABLED(CONFIG_NF_SOCKET_IPV6)
+ case NFPROTO_IPV6:
+ sk = nf_sk_lookup_slow_v6(nft_net(pkt), skb, nft_in(pkt));
+ break;
+#endif
+ default:
+ WARN_ON_ONCE(1);
+ regs->verdict.code = NFT_BREAK;
+ return;
+ }
+
+ if(!sk) {
+ nft_reg_store8(dest, 0);
+ return;
+ }
+
+ skb->sk = sk; // So that subsequent socket matching not to require other lookups
+
+ switch(priv->key) {
+ case NFT_SOCKET_TRANSPARENT:
+ nft_reg_store8(dest, nf_sk_is_transparent(sk));
+ break;
+ default:
+ WARN_ON(1);
+ regs->verdict.code = NFT_BREAK;
+ }
+}
+
+static const struct nla_policy nft_socket_policy[NFTA_SOCKET_MAX + 1] = {
+ [NFTA_SOCKET_KEY] = { .type = NLA_U32 },
+ [NFTA_SOCKET_DREG] = { .type = NLA_U32 },
+};
+
+static int nft_socket_init(const struct nft_ctx *ctx,
+ const struct nft_expr *expr,
+ const struct nlattr * const tb[])
+{
+ struct nft_socket *priv = nft_expr_priv(expr);
+ unsigned int len;
+
+ if (!tb[NFTA_SOCKET_DREG] || !tb[NFTA_SOCKET_KEY])
+ return -EINVAL;
+
+ switch(ctx->family) {
+ case NFPROTO_IPV4:
+#if IS_ENABLED(CONFIG_NF_SOCKET_IPV6)
+ case NFPROTO_IPV6:
+#endif
+ case NFPROTO_INET:
+ break;
+ default:
+ return -EOPNOTSUPP;
+ }
+
+ priv->key = ntohl(nla_get_u32(tb[NFTA_SOCKET_KEY]));
+ switch(priv->key) {
+ case NFT_SOCKET_TRANSPARENT:
+ len = sizeof(u8);
+ break;
+ default:
+ return -EOPNOTSUPP;
+ }
+
+ priv->dreg = nft_parse_register(tb[NFTA_SOCKET_DREG]);
+ return nft_validate_register_store(ctx, priv->dreg, NULL,
+ NFT_DATA_VALUE, len);
+}
+
+static int nft_socket_dump(struct sk_buff *skb,
+ const struct nft_expr *expr)
+{
+ const struct nft_socket *priv = nft_expr_priv(expr);
+
+ if (nla_put_u32(skb, NFTA_SOCKET_KEY, htonl(priv->key)))
+ return -1;
+ if (nft_dump_register(skb, NFTA_SOCKET_DREG, priv->dreg))
+ return -1;
+ return 0;
+}
+
+struct nft_expr_type nft_socket_type;
+static const struct nft_expr_ops nft_socket_ops = {
+ .type = &nft_socket_type,
+ .size = NFT_EXPR_SIZE(sizeof(struct nft_socket)),
+ .eval = nft_socket_eval,
+ .init = nft_socket_init,
+ .dump = nft_socket_dump,
+};
+
+struct nft_expr_type nft_socket_type __read_mostly = {
+ .name = "socket",
+ .ops = &nft_socket_ops,
+ .policy = nft_socket_policy,
+ .maxattr = NFTA_SOCKET_MAX,
+ .owner = THIS_MODULE,
+};
+
+static int __init nft_socket_module_init(void)
+{
+ return nft_register_expr(&nft_socket_type);
+}
+
+static void __exit nft_socket_module_exit(void)
+{
+ nft_unregister_expr(&nft_socket_type);
+}
+
+module_init(nft_socket_module_init);
+module_exit(nft_socket_module_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Máté Eckl");
+MODULE_DESCRIPTION("nf_tables socket match module");
--
ecklm
--
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