This patch implements the kernel side of the TCP option patch.
Signed-off-by: Manuel Messner <mm@xxxxxxxxxx>
Reviewed-by: Florian Westphal <fw@xxxxxxxxx>
---
include/uapi/linux/netfilter/nf_tables.h | 17 ++++-
net/netfilter/Kconfig | 4 +-
net/netfilter/nft_exthdr.c | 120 +++++++++++++++++++++++++++----
3 files changed, 125 insertions(+), 16 deletions(-)
diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
index b00a05d1ee56..6c0c9efddad6 100644
--- a/include/uapi/linux/netfilter/nf_tables.h
+++ b/include/uapi/linux/netfilter/nf_tables.h
@@ -705,12 +705,13 @@ enum nft_payload_attributes {
#define NFTA_PAYLOAD_MAX (__NFTA_PAYLOAD_MAX - 1)
/**
- * enum nft_exthdr_attributes - nf_tables IPv6 extension header expression netlink attributes
+ * enum nft_exthdr_attributes - nf_tables extension header expression netlink attributes
*
* @NFTA_EXTHDR_DREG: destination register (NLA_U32: nft_registers)
* @NFTA_EXTHDR_TYPE: extension header type (NLA_U8)
* @NFTA_EXTHDR_OFFSET: extension header offset (NLA_U32)
* @NFTA_EXTHDR_LEN: extension header length (NLA_U32)
+ * @NFTA_EXTHDR_OP: option match type (NLA_U8)
*/
enum nft_exthdr_attributes {
NFTA_EXTHDR_UNSPEC,
@@ -718,11 +719,25 @@ enum nft_exthdr_attributes {
NFTA_EXTHDR_TYPE,
NFTA_EXTHDR_OFFSET,
NFTA_EXTHDR_LEN,
+ NFTA_EXTHDR_OP,
__NFTA_EXTHDR_MAX
};
#define NFTA_EXTHDR_MAX (__NFTA_EXTHDR_MAX - 1)
/**
+ * enum nft_exthdr_op - nf_tables match options
+ *
+ * @NFT_EXTHDR_OP_IPV6: match against ipv6 extension headers
+ * @NFT_EXTHDR_OP_TCP: match against tcp options
+ */
+enum nft_exthdr_op {
+ NFT_EXTHDR_OP_IPV6,
+ NFT_EXTHDR_OP_TCPOPT,
+ __NFT_EXTHDR_OP_MAX
+};
+#define NFT_EXTHDR_OP_MAX (__NFT_EXTHDR_OP_MAX - 1)
+
+/**
* enum nft_meta_keys - nf_tables meta expression keys
*
* @NFT_META_LEN: packet length (skb->len)
diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig
index c69eee3a0e54..e44c0e1ec0c5 100644
--- a/net/netfilter/Kconfig
+++ b/net/netfilter/Kconfig
@@ -467,10 +467,10 @@ config NF_TABLES_NETDEV
This option enables support for the "netdev" table.
config NFT_EXTHDR
- tristate "Netfilter nf_tables IPv6 exthdr module"
+ tristate "Netfilter nf_tables exthdr module"
help
This option adds the "exthdr" expression that you can use to match
- IPv6 extension headers.
+ IPv6 extension headers and tcp options.
config NFT_META
tristate "Netfilter nf_tables meta module"
diff --git a/net/netfilter/nft_exthdr.c b/net/netfilter/nft_exthdr.c
index 47beb3abcc9d..bc6518a8fe6c 100644
--- a/net/netfilter/nft_exthdr.c
+++ b/net/netfilter/nft_exthdr.c
@@ -15,19 +15,28 @@
#include <linux/netfilter.h>
#include <linux/netfilter/nf_tables.h>
#include <net/netfilter/nf_tables.h>
-// FIXME:
-#include <net/ipv6.h>
+#include <net/tcp.h>
struct nft_exthdr {
u8 type;
u8 offset;
u8 len;
+ u8 op;
enum nft_registers dreg:8;
};
-static void nft_exthdr_eval(const struct nft_expr *expr,
- struct nft_regs *regs,
- const struct nft_pktinfo *pkt)
+static unsigned int optlen(const u8 *opt, unsigned int offset)
+{
+ /* Beware zero-length options: make finite progress */
+ if (opt[offset] <= TCPOPT_NOP || opt[offset + 1] == 0)
+ return 1;
+ else
+ return opt[offset + 1];
+}
+
+static void nft_exthdr_ipv6_eval(const struct nft_expr *expr,
+ struct nft_regs *regs,
+ const struct nft_pktinfo *pkt)
{
struct nft_exthdr *priv = nft_expr_priv(expr);
u32 *dest = ®s->data[priv->dreg];
@@ -47,11 +56,59 @@ static void nft_exthdr_eval(const struct nft_expr *expr,
regs->verdict.code = NFT_BREAK;
}
+static void nft_exthdr_tcp_eval(const struct nft_expr *expr,
+ struct nft_regs *regs,
+ const struct nft_pktinfo *pkt)
+{
+ u8 buff[sizeof(struct tcphdr) + MAX_TCP_OPTION_SPACE];
+ struct nft_exthdr *priv = nft_expr_priv(expr);
+ unsigned int i, optl, tcphdr_len, offset;
+ u32 *dest = ®s->data[priv->dreg];
+ struct tcphdr *tcph;
+ u8 *opt;
+
+ if (!pkt->tprot_set || pkt->tprot != IPPROTO_TCP)
+ goto err;
+
+ tcph = skb_header_pointer(pkt->skb, pkt->xt.thoff, sizeof(*tcph), buff);
+ if (!tcph)
+ goto err;
+
+ tcphdr_len = __tcp_hdrlen(tcph);
+ if (tcphdr_len < sizeof(*tcph))
+ goto err;
+
+ tcph = skb_header_pointer(pkt->skb, pkt->xt.thoff, tcphdr_len, buff);
+ if (!tcph)
+ goto err;
+
+ opt = (u8 *)tcph;
+ for (i = sizeof(*tcph); i < tcphdr_len - 1; i += optl) {
+ optl = optlen(opt, i);
+
+ if (priv->type != opt[i])
+ continue;
+
+ if (i + optl > tcphdr_len || priv->len + priv->offset > optl)
+ goto err;
+
+ offset = i + priv->offset;
+ dest[priv->len / NFT_REG32_SIZE] = 0;
+ memcpy(dest, opt + offset, priv->len);
+
+ return;
+ }
+
+err:
+ regs->verdict.code = NFT_BREAK;
+}
+
static const struct nla_policy nft_exthdr_policy[NFTA_EXTHDR_MAX + 1] = {
[NFTA_EXTHDR_DREG] = { .type = NLA_U32 },
[NFTA_EXTHDR_TYPE] = { .type = NLA_U8 },
[NFTA_EXTHDR_OFFSET] = { .type = NLA_U32 },
[NFTA_EXTHDR_LEN] = { .type = NLA_U32 },
+ [NFTA_EXTHDR_OP] = { .type = NLA_U32 },
};
static int nft_exthdr_init(const struct nft_ctx *ctx,
@@ -59,13 +116,13 @@ static int nft_exthdr_init(const struct nft_ctx *ctx,
const struct nlattr * const tb[])
{
struct nft_exthdr *priv = nft_expr_priv(expr);
- u32 offset, len;
+ u32 offset, len, op = NFT_EXTHDR_OP_IPV6;
int err;
- if (tb[NFTA_EXTHDR_DREG] == NULL ||
- tb[NFTA_EXTHDR_TYPE] == NULL ||
- tb[NFTA_EXTHDR_OFFSET] == NULL ||
- tb[NFTA_EXTHDR_LEN] == NULL)
+ if (!tb[NFTA_EXTHDR_DREG] ||
+ !tb[NFTA_EXTHDR_TYPE] ||
+ !tb[NFTA_EXTHDR_OFFSET] ||
+ !tb[NFTA_EXTHDR_LEN])
return -EINVAL;
err = nft_parse_u32_check(tb[NFTA_EXTHDR_OFFSET], U8_MAX, &offset);
@@ -76,10 +133,17 @@ static int nft_exthdr_init(const struct nft_ctx *ctx,
if (err < 0)
return err;
+ if (tb[NFTA_EXTHDR_OP]) {
+ err = nft_parse_u32_check(tb[NFTA_EXTHDR_OP], U8_MAX, &op);
+ if (err < 0)
+ return err;
+ }
+
priv->type = nla_get_u8(tb[NFTA_EXTHDR_TYPE]);
priv->offset = offset;
priv->len = len;
priv->dreg = nft_parse_register(tb[NFTA_EXTHDR_DREG]);
+ priv->op = op;
return nft_validate_register_store(ctx, priv->dreg, NULL,
NFT_DATA_VALUE, priv->len);
@@ -97,6 +161,8 @@ static int nft_exthdr_dump(struct sk_buff *skb, const struct nft_expr *expr)
goto nla_put_failure;
if (nla_put_be32(skb, NFTA_EXTHDR_LEN, htonl(priv->len)))
goto nla_put_failure;
+ if (nla_put_be32(skb, NFTA_EXTHDR_OP, htonl(priv->op)))
+ goto nla_put_failure;
return 0;
nla_put_failure:
@@ -104,17 +170,45 @@ static int nft_exthdr_dump(struct sk_buff *skb, const struct nft_expr *expr)
}
static struct nft_expr_type nft_exthdr_type;
-static const struct nft_expr_ops nft_exthdr_ops = {
+static const struct nft_expr_ops nft_exthdr_ipv6_ops = {
.type = &nft_exthdr_type,
.size = NFT_EXPR_SIZE(sizeof(struct nft_exthdr)),
- .eval = nft_exthdr_eval,
+ .eval = nft_exthdr_ipv6_eval,
.init = nft_exthdr_init,
.dump = nft_exthdr_dump,
};
+static const struct nft_expr_ops nft_exthdr_tcp_ops = {
+ .type = &nft_exthdr_type,
+ .size = NFT_EXPR_SIZE(sizeof(struct nft_exthdr)),
+ .eval = nft_exthdr_tcp_eval,
+ .init = nft_exthdr_init,
+ .dump = nft_exthdr_dump,
+};
+
+static const struct nft_expr_ops *
+nft_exthdr_select_ops(const struct nft_ctx *ctx,
+ const struct nlattr * const tb[])
+{
+ u32 op;
+
+ if (!tb[NFTA_EXTHDR_OP])
+ return &nft_exthdr_ipv6_ops;
+
+ op = ntohl(nla_get_u32(tb[NFTA_EXTHDR_OP]));
+ switch (op) {
+ case NFT_EXTHDR_OP_TCPOPT:
+ return &nft_exthdr_tcp_ops;
+ case NFT_EXTHDR_OP_IPV6:
+ return &nft_exthdr_ipv6_ops;
+ }
+
+ return ERR_PTR(-EOPNOTSUPP);
+}
+
static struct nft_expr_type nft_exthdr_type __read_mostly = {
.name = "exthdr",
- .ops = &nft_exthdr_ops,
+ .select_ops = &nft_exthdr_select_ops,
.policy = nft_exthdr_policy,
.maxattr = NFTA_EXTHDR_MAX,
.owner = THIS_MODULE,
--
2.11.1
--
To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
