/* * include/haproxy/htx-t.h * This file declares the types and constants used the internal HTTP messages * * Copyright (C) 2018 HAProxy Technologies, Christopher Faulet * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation, version 2.1 * exclusively. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #ifndef _HAPROXY_HTX_T_H #define _HAPROXY_HTX_T_H #include #include /* * The internal representation of an HTTP message, called HTX, is a structure * with useful information on the message followed by a contiguous array * containing parts of the message, called blocks. A block is composed of * metadata (htx_blk) and the associated payload. Blocks' metadata are stored * starting from the end of the array while their payload are stored at the * beginning. Blocks' metadata are often simply called blocks. it is a misuse of * language that's simplify explanations. * * * +-----+---------------+------------------------------+--------------+ * | HTX | PAYLOADS ==> | | <== HTX_BLKs | * +-----+---------------+------------------------------+--------------+ * ^ * blocks[] (the beginning of the bocks array) * * * The blocks part remains linear and sorted. You may think about it as an array * with negative indexes. But, instead of using negative indexes, we use * positive positions to identify a block. This position is then converted to a * address relatively to the beginning of the blocks array. * * * .....--+------------------------------+-----+-----+ * | ... | BLK | BLK | * .....--+------------------------------+-----+-----+ * ^ ^ * Addr of the block Addr of the block * at the position 1 at the position 0 * * * The payloads part is a raw space that may wrap. You never access to a block's * payload directly. Instead you get a block to retrieve the address of its * payload. When no more space left between blocks and payloads parts, the free * space at the beginning, if any, is used. * * * +----------- WRAPPING ------------------------+ * | | * V | * +-----+-------------+---------------+---------------++--------------+ * | HTX | PAYLOAD ==> | | PAYLOADS ==X || X== HTX_BLKs | * +-----+-------------+---------------+---------------++--------------+ * * * The blocks part, on its side, never wrap. If we have no space to allocate a * new block and if there is a hole at the beginning of the blocks part (so at * the end of the blocks array), we move back all blocks.x * * * ...+--------------+----------+ blocks ...+----------+--------------+ * | X== HTX_BLKS | | defrag | | <== HTX_BLKS | * ...+--------------+----------+ =====> ...+----------+--------------+ * * * At the end, if payload wrapping or blocks defragmentation is not enough, some * free space may be get back with a full defragmentation. This way, the holes in * the middle are not reusable but count in the available free space. The only * way to reuse this lost space is to fully defragmenate the HTX message. * * - * - * * An HTX block is as well a header as a body part or a trailer. For all these * types of block, a payload is attached to the block. It can also be a mark, * like the end-of-headers or end-of-message. For these blocks, there is no * payload but it count for a byte. It is important to not skip it when data are * forwarded. Metadata of an HTX block are composed of 2 fields : * * - .info : It a 32 bits field containing the block's type on 4 bits * followed by the payload length. See below for details. * * - .addr : The payload's address, if any, relatively to the beginning the * array used to store the HTX message itself. * * htx_blk.info representation : * * 0b 0000 0000 0000 0000 0000 0000 0000 0000 * ---- ------------------------ --------- * type value (1 MB max) name length (header/trailer) * ---------------------------------- * data length (256 MB max) * (body, method, path, version, status, reason) * * types : * - 0000 = request start-line * - 0001 = response start-line * - 0010 = header * - 0011 = pseudo-header ou "special" header * - 0100 = end-of-headers * - 0101 = data * - 0110 = trailer * - 0111 = end-of-trailers * - 1000 = end-of-message * ... * - 1111 = unused * */ /* HTX start-line flags */ #define HTX_SL_F_NONE 0x00000000 #define HTX_SL_F_IS_RESP 0x00000001 /* It is the response start-line (unset means the request one) */ #define HTX_SL_F_XFER_LEN 0x00000002 /* The message xfer size can be dertermined */ #define HTX_SL_F_XFER_ENC 0x00000004 /* The transfer-encoding header was found in message */ #define HTX_SL_F_CLEN 0x00000008 /* The content-length header was found in message */ #define HTX_SL_F_CHNK 0x00000010 /* The message payload is chunked */ #define HTX_SL_F_VER_11 0x00000020 /* The message indicates version 1.1 or above */ #define HTX_SL_F_BODYLESS 0x00000040 /* The message has no body (content-length = 0) */ #define HTX_SL_F_HAS_SCHM 0x00000080 /* The scheme is explicitly specified */ #define HTX_SL_F_SCHM_HTTP 0x00000100 /* The scheme HTTP should be used */ #define HTX_SL_F_SCHM_HTTPS 0x00000200 /* The scheme HTTPS should be used */ #define HTX_SL_F_HAS_AUTHORITY 0x00000400 /* The request authority is explicitly specified */ #define HTX_SL_F_NORMALIZED_URI 0x00000800 /* The received URI is normalized (an implicit absolute-uri form) */ /* HTX flags */ #define HTX_FL_NONE 0x00000000 #define HTX_FL_PARSING_ERROR 0x00000001 /* Set when a parsing error occurred */ #define HTX_FL_PROCESSING_ERROR 0x00000002 /* Set when a processing error occurred */ /* 0x00000004 unused */ #define HTX_FL_PROXY_RESP 0x00000008 /* Set when the response was generated by HAProxy */ #define HTX_FL_EOI 0x00000010 /* Set when end-of-input is reached from the HTX point of view * (at worst, on the EOM block is missing) */ /* HTX block's type (max 15). */ enum htx_blk_type { HTX_BLK_REQ_SL = 0, /* Request start-line */ HTX_BLK_RES_SL = 1, /* Response start-line */ HTX_BLK_HDR = 2, /* header name/value block */ HTX_BLK_EOH = 3, /* end-of-headers block */ HTX_BLK_DATA = 4, /* data block */ HTX_BLK_TLR = 5, /* trailer name/value block */ HTX_BLK_EOT = 6, /* end-of-trailers block */ HTX_BLK_EOM = 7, /* end-of-message block */ /* 8 .. 14 unused */ HTX_BLK_UNUSED = 15, /* unused/removed block */ }; /* One HTX block descriptor */ struct htx_blk { uint32_t addr; /* relative storage address of the block's payload */ uint32_t info; /* information about the block (type, length) */ }; /* Composite return value used by some HTX functions */ struct htx_ret { int32_t ret; /* A numerical value */ struct htx_blk *blk; /* An HTX block */ }; /* HTX start-line */ struct htx_sl { unsigned int flags; /* HTX_SL_F_* */ union { struct { enum http_meth_t meth; /* method */ } req; struct { uint16_t status; /* status code */ } res; } info; /* XXX 2 bytes unused */ int32_t hdrs_bytes; /* Bytes held by all headers, as seen by the mux * during parsing, from this start-line to the * corresponding EOH. -1 if unknown */ unsigned int len[3]; /* length of different parts of the start-line */ char l[VAR_ARRAY]; }; /* Internal representation of an HTTP message */ struct htx { uint32_t size; /* the array size, in bytes, used to store the HTTP message itself */ uint32_t data; /* the data size, in bytes. To known to total size used by all allocated * blocks (blocks and their contents), you need to add size used by blocks, * i.e. [ used * sizeof(struct htx_blk *) ] */ int32_t tail; /* newest inserted block. -1 if the HTX message is empty */ int32_t head; /* oldest inserted block. -1 if the HTX message is empty */ int32_t first; /* position of the first block to (re)start the analyse. -1 if unset. */ uint32_t tail_addr; /* start address of the free space in front of the the blocks table */ uint32_t head_addr; /* start address of the free space at the beginning */ uint32_t end_addr; /* end address of the free space at the beginning */ uint64_t extra; /* known bytes amount remaining to receive */ uint32_t flags; /* HTX_FL_* */ /* XXX 4 bytes unused */ /* Blocks representing the HTTP message itself */ char blocks[VAR_ARRAY] __attribute__((aligned(8))); }; #endif /* _HAPROXY_HTX_T_H */ /* * Local variables: * c-indent-level: 8 * c-basic-offset: 8 * End: */