![Pablo Neira Ayuso](/assets/img/avatar_default.png)
This patch adds a new flag that signals the kernel to update layer 4 checksum if the packet field belongs to the layer 4 pseudoheader. This implicitly provides stateless NAT 1:1 that is useful under very specific usecases. Since rules mangling layer 3 fields that are part of the pseudoheader may potentially convey any layer 4 packet, we have to deal with the layer 4 checksum adjustment using protocol specific code. This patch adds support for TCP, UDP and ICMPv6, since they include the pseudoheader in the layer 4 checksum calculation. ICMP doesn't, so we can skip it. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
55 lines
1.4 KiB
C
55 lines
1.4 KiB
C
#ifndef _NET_NF_TABLES_CORE_H
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#define _NET_NF_TABLES_CORE_H
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extern struct nft_expr_type nft_imm_type;
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extern struct nft_expr_type nft_cmp_type;
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extern struct nft_expr_type nft_lookup_type;
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extern struct nft_expr_type nft_bitwise_type;
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extern struct nft_expr_type nft_byteorder_type;
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extern struct nft_expr_type nft_payload_type;
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extern struct nft_expr_type nft_dynset_type;
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extern struct nft_expr_type nft_range_type;
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int nf_tables_core_module_init(void);
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void nf_tables_core_module_exit(void);
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struct nft_cmp_fast_expr {
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u32 data;
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enum nft_registers sreg:8;
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u8 len;
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};
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/* Calculate the mask for the nft_cmp_fast expression. On big endian the
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* mask needs to include the *upper* bytes when interpreting that data as
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* something smaller than the full u32, therefore a cpu_to_le32 is done.
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*/
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static inline u32 nft_cmp_fast_mask(unsigned int len)
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{
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return cpu_to_le32(~0U >> (FIELD_SIZEOF(struct nft_cmp_fast_expr,
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data) * BITS_PER_BYTE - len));
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}
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extern const struct nft_expr_ops nft_cmp_fast_ops;
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struct nft_payload {
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enum nft_payload_bases base:8;
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u8 offset;
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u8 len;
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enum nft_registers dreg:8;
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};
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struct nft_payload_set {
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enum nft_payload_bases base:8;
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u8 offset;
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u8 len;
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enum nft_registers sreg:8;
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u8 csum_type;
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u8 csum_offset;
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u8 csum_flags;
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};
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extern const struct nft_expr_ops nft_payload_fast_ops;
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extern struct static_key_false nft_trace_enabled;
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#endif /* _NET_NF_TABLES_CORE_H */
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