payload.h File Reference

#include <nftables.h>
#include <proto.h>

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Functions
struct expr *	payload_expr_alloc (const struct location *loc, const struct proto_desc *desc, unsigned int type)
void	payload_init_raw (struct expr *expr, enum proto_bases base, unsigned int offset, unsigned int len)
int	payload_gen_dependency (struct eval_ctx *ctx, const struct expr *expr, struct stmt **res)
	payload_gen_dependency - generate match expression on payload dependency More...
bool	payload_is_adjacent (const struct expr *e1, const struct expr *e2)
	payload_is_adjacent - return whether two payload expressions refer to adjacent header locations More...
struct expr *	payload_expr_join (const struct expr *e1, const struct expr *e2)
	payload_expr_join - join two adjacent payload expressions More...
void	payload_expr_expand (struct list_head *list, struct expr *expr, const struct proto_ctx *ctx)
	payload_expr_expand - expand raw merged adjacent payload expressions into its original components More...
void	payload_expr_complete (struct expr *expr, const struct proto_ctx *ctx)
	payload_expr_complete - fill in type information of a raw payload expr More...

Function Documentation

struct expr* payload_expr_alloc	(	const struct location *	loc,
		const struct proto_desc *	desc,
		unsigned int	type
	)

References proto_desc::base, expr::base, proto_hdr_template::byteorder, expr::desc, proto_hdr_template::dtype, expr_alloc(), EXPR_F_PROTOCOL, expr::flags, flags, proto_hdr_template::len, NULL, proto_hdr_template::offset, expr::payload, PROTO_BASE_INVALID, proto_unknown, proto_unknown_template, proto_desc::protocol_key, proto_desc::templates, expr::tmpl, and type.

Referenced by payload_expr_expand(), payload_expr_join(), and payload_gen_dependency().

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void payload_expr_complete	(	struct expr *	expr,
		const struct proto_ctx *	ctx
	)

payload_expr_complete - fill in type information of a raw payload expr

: the payload expression : protocol context

Complete the type of a raw payload expression based on the context. If insufficient information is available the expression remains unchanged.

References array_size, proto_desc::base, proto_desc::desc, proto_ctx::desc, proto_hdr_template::dtype, expr::dtype, EXPR_PAYLOAD, proto_hdr_template::len, expr::len, NULL, proto_hdr_template::offset, expr::ops, expr::payload, proto_ctx::protocol, proto_desc::templates, and expr_ops::type.

void payload_expr_expand	(	struct list_head *	list,
		struct expr *	expr,
		const struct proto_ctx *	ctx
	)

payload_expr_expand - expand raw merged adjacent payload expressions into its original components

: list to append expanded payload expressions to : the payload expression to expand : protocol context

Expand a merged adjacent payload expression into its original components by splitting elements off the beginning matching a payload template.

Note: this requires all payload templates to be specified in ascending offset order.

References array_size, proto_desc::base, proto_desc::desc, proto_ctx::desc, EXPR_PAYLOAD, proto_hdr_template::len, expr::len, expr::location, new, NULL, proto_hdr_template::offset, expr::ops, expr::payload, payload_expr_alloc(), payload_init_raw(), proto_ctx::protocol, proto_desc::templates, and expr_ops::type.

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struct expr* payload_expr_join	(	const struct expr *	e1,
		const struct expr *	e2
	)

payload_expr_join - join two adjacent payload expressions

: first payload expression : second payload expression

References internal_location, expr::len, NULL, expr::payload, payload_expr_alloc(), and payload_is_adjacent().

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int payload_gen_dependency	(	struct eval_ctx *	ctx,
		const struct expr *	expr,
		struct stmt **	res
	)

payload_gen_dependency - generate match expression on payload dependency

: evaluation context : payload expression : dependency expression

Generate matches on protocol dependencies. There are two different kinds of dependencies:

• A payload expression for a base above the hook base requires a match on the protocol value in the lower layer header.

• A payload expression for a base below the hook base is invalid in the output path since the lower layer header does not exist when the packet is classified. In the input path a payload expressions for a base exactly one below the hook base is valid. In this case a match on the device type is required to verify that we're dealing with the expected protocol.

  Note: since it is unknown to userspace which hooks a chain is called from, it is not explicitly verified. The NFT_META_IIFTYPE match will only match in the input path though.

References arphrd_type, hook_proto_desc::base, BITS_PER_BYTE, datatype::byteorder, BYTEORDER_HOST_ENDIAN, constant_expr_alloc(), proto_desc::desc, proto_ctx::desc, proto_hdr_template::dtype, expr_error, expr_stmt_alloc(), proto_ctx::family, expr::left, proto_hdr_template::len, expr::location, meta_expr_alloc(), proto_hdr_template::meta_key, eval_ctx::msgs, proto_desc::name, NFPROTO_BRIDGE, NFPROTO_INET, NFT_META_IIFTYPE, NULL, OP_EQ, expr::ops, expr::payload, payload_expr_alloc(), eval_ctx::pctx, expr_ops::pctx_update, PROTO_BASE_LL_HDR, proto_base_names, PROTO_BASE_TRANSPORT_HDR, proto_dev_type(), proto_eth, proto_find_num(), proto_inet, proto_inet_service, proto_ctx::protocol, proto_desc::protocol_key, relational_expr_alloc(), expr::right, stmt_evaluate(), proto_desc::templates, and type.

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void payload_init_raw	(	struct expr *	expr,
		enum proto_bases	base,
		unsigned int	offset,
		unsigned int	len
	)

References expr::base, len, expr::len, expr::offset, and expr::payload.

Referenced by payload_expr_expand().

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bool payload_is_adjacent	(	const struct expr *	e1,
		const struct expr *	e2
	)

payload_is_adjacent - return whether two payload expressions refer to adjacent header locations

: first payload expression : second payload expression

References expr::len, and expr::payload.

Referenced by payload_expr_join().

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