diff options
| author | Phil Sutter <phil@nwl.cc> | 2017-01-17 22:51:26 +0100 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2017-02-08 14:14:09 +0100 |
| commit | c078ca3b0c5bf82c2b31906c446d6e2ad8ea0783 (patch) | |
| tree | bebb843cfdedd03db69bcec8981e66503079f1ca | |
| parent | 6e7bc478c9a006c701c14476ec9d389a484b4864 (diff) | |
netfilter: nft_exthdr: Add support for existence check
If NFT_EXTHDR_F_PRESENT is set, exthdr will not copy any header field
data into *dest, but instead set it to 1 if the header is found and 0
otherwise.
Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
| -rw-r--r-- | include/uapi/linux/netfilter/nf_tables.h | 6 | ||||
| -rw-r--r-- | net/netfilter/nft_exthdr.c | 22 |
2 files changed, 26 insertions, 2 deletions
diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h index 7b730cab99bd..53aac8b8ed6b 100644 --- a/include/uapi/linux/netfilter/nf_tables.h +++ b/include/uapi/linux/netfilter/nf_tables.h @@ -704,6 +704,10 @@ enum nft_payload_attributes { }; #define NFTA_PAYLOAD_MAX (__NFTA_PAYLOAD_MAX - 1) +enum nft_exthdr_flags { + NFT_EXTHDR_F_PRESENT = (1 << 0), +}; + /** * enum nft_exthdr_attributes - nf_tables IPv6 extension header expression netlink attributes * @@ -711,6 +715,7 @@ enum nft_payload_attributes { * @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_FLAGS: extension header flags (NLA_U32) */ enum nft_exthdr_attributes { NFTA_EXTHDR_UNSPEC, @@ -718,6 +723,7 @@ enum nft_exthdr_attributes { NFTA_EXTHDR_TYPE, NFTA_EXTHDR_OFFSET, NFTA_EXTHDR_LEN, + NFTA_EXTHDR_FLAGS, __NFTA_EXTHDR_MAX }; #define NFTA_EXTHDR_MAX (__NFTA_EXTHDR_MAX - 1) diff --git a/net/netfilter/nft_exthdr.c b/net/netfilter/nft_exthdr.c index 47beb3abcc9d..a89e5ab150db 100644 --- a/net/netfilter/nft_exthdr.c +++ b/net/netfilter/nft_exthdr.c @@ -23,6 +23,7 @@ struct nft_exthdr { u8 offset; u8 len; enum nft_registers dreg:8; + u8 flags; }; static void nft_exthdr_eval(const struct nft_expr *expr, @@ -35,8 +36,12 @@ static void nft_exthdr_eval(const struct nft_expr *expr, int err; err = ipv6_find_hdr(pkt->skb, &offset, priv->type, NULL, NULL); - if (err < 0) + if (priv->flags & NFT_EXTHDR_F_PRESENT) { + *dest = (err >= 0); + return; + } else if (err < 0) { goto err; + } offset += priv->offset; dest[priv->len / NFT_REG32_SIZE] = 0; @@ -52,6 +57,7 @@ static const struct nla_policy nft_exthdr_policy[NFTA_EXTHDR_MAX + 1] = { [NFTA_EXTHDR_TYPE] = { .type = NLA_U8 }, [NFTA_EXTHDR_OFFSET] = { .type = NLA_U32 }, [NFTA_EXTHDR_LEN] = { .type = NLA_U32 }, + [NFTA_EXTHDR_FLAGS] = { .type = NLA_U32 }, }; static int nft_exthdr_init(const struct nft_ctx *ctx, @@ -59,7 +65,7 @@ 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, flags = 0; int err; if (tb[NFTA_EXTHDR_DREG] == NULL || @@ -76,10 +82,20 @@ static int nft_exthdr_init(const struct nft_ctx *ctx, if (err < 0) return err; + if (tb[NFTA_EXTHDR_FLAGS]) { + err = nft_parse_u32_check(tb[NFTA_EXTHDR_FLAGS], U8_MAX, &flags); + if (err < 0) + return err; + + if (flags & ~NFT_EXTHDR_F_PRESENT) + return -EINVAL; + } + 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->flags = flags; return nft_validate_register_store(ctx, priv->dreg, NULL, NFT_DATA_VALUE, priv->len); @@ -97,6 +113,8 @@ 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_FLAGS, htonl(priv->flags))) + goto nla_put_failure; return 0; nla_put_failure: |