include/common/hpack-enc.h - haproxy - Gitiles

 /*
  * HPACK compressor (RFC7541)
  *
  * Copyright (C) 2014-2017 Willy Tarreau <willy@haproxy.org>
  * Copyright (C) 2017 HAProxy Technologies
  *
  * Permission is hereby granted, free of charge, to any person obtaining
  * a copy of this software and associated documentation files (the
  * "Software"), to deal in the Software without restriction, including
  * without limitation the rights to use, copy, modify, merge, publish,
  * distribute, sublicense, and/or sell copies of the Software, and to
  * permit persons to whom the Software is furnished to do so, subject to
  * the following conditions:
  *
  * The above copyright notice and this permission notice shall be
  * included in all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
  * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
  * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
  * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  * OTHER DEALINGS IN THE SOFTWARE.
  */

 #ifndef _COMMON_HPACK_ENC_H
 #define _COMMON_HPACK_ENC_H

 #include <inttypes.h>
 #include <string.h>
 #include <common/buf.h>
 #include <common/config.h>
 #include <common/http.h>
 #include <common/ist.h>

 int hpack_encode_header(struct buffer *out, const struct ist n,
 			const struct ist v);

 /* Returns the number of bytes required to encode the string length <len>. The
  * number of usable bits is an integral multiple of 7 plus 6 for the last byte.
  * The maximum number of bytes returned is 4 (2097279 max length). Larger values
  * return 0.
  */
 static inline int hpack_len_to_bytes(size_t len)
 {
 	ssize_t slen = len;

 	slen -= 127;
 	if (__builtin_expect(slen < 0, 1))
 		return 1;
 	if (slen < (1 << 14)) {
 		if (__builtin_expect(slen < (1 << 7), 1))
 			return 2;
 		else
 			return 3;
 	}
 	if (slen < (1 << 21))
 		return 4;
 	return 0;
 }

 /* Encodes <len> into <out>+<pos> and return the new position. The caller is
  * responsible for checking for available room using hpack_len_to_bytes()
  * first.
  */
 static inline int hpack_encode_len(char *out, int pos, int len)
 {
 	int code = len - 127;

 	if (code < 0) {
 		out[pos++] = len;
 	} else {
 		out[pos++] = 127;
 		for (; code >= 128; code >>= 7)
 			out[pos++] = code | 128;
 		out[pos++] = code;
 	}
 	return pos;
 }

 /* Tries to encode header field index <idx> with short value <val> into the
  * aligned buffer <out>. Returns non-zero on success, 0 on failure (buffer
  * full). The caller is responsible for ensuring that the length of <val> is
  * strictly lower than 127, and that <idx> is lower than 64 (static list only),
  * and that the buffer is aligned (head==0).
  */
 static inline int hpack_encode_short_idx(struct buffer *out, int idx, struct ist val)
 {
 	if (out->data + 2 + val.len > out->size)
 		return 0;

 	/* literal header field with incremental indexing */
 	out->area[out->data++] = idx | 0x40;
 	out->area[out->data++] = val.len;
 	ist2bin(&out->area[out->data], val);
 	out->data += val.len;
 	return 1;
 }

 /* Tries to encode header field index <idx> with long value <val> into the
  * aligned buffer <out>. Returns non-zero on success, 0 on failure (buffer
  * full). The caller is responsible for ensuring <idx> is lower than 64 (static
  * list only), and that the buffer is aligned (head==0).
  */
 static inline int hpack_encode_long_idx(struct buffer *out, int idx, struct ist val)
 {
 	int len = out->data;

 	if (!hpack_len_to_bytes(val.len) ||
 	    1 + len + hpack_len_to_bytes(val.len) + val.len > out->size)
 		return 0;

 	/* emit literal with indexing (7541#6.2.1) :
 	 * [ 0 | 1 | Index (6+) ]
 	 */
 	out->area[len++] = idx | 0x40;
 	len = hpack_encode_len(out->area, len, val.len);
 	memcpy(out->area + len, val.ptr, val.len);
 	len += val.len;

 	out->data = len;
 	return 1;
 }

 /* Tries to encode a :status pseudo-header with the integer status <status>
  * into the aligned buffer <out>. Returns non-zero on success, 0 on failure
  * (buffer full). The caller is responsible for ensuring that the status is
  * comprised between 100 and 999 inclusive and that the buffer is aligned. It's
  * inlined because it's easily optimizable by the compiler.
  */
 static inline int hpack_encode_int_status(struct buffer *out, unsigned int status)
 {
 	int len = out->data;
 	int size = out->size;
 	unsigned char c = 0;

 	/* try to emit a single byte code */
 	len++;
 	if (__builtin_expect(len > size, 0))
 		goto fail;

 	c = (status <= 304) ?
 		(status <= 204) ?
 			(status == 204) ? 0x89 :
 			(status == 200) ? 0x88 :
 		0: /* > 204 */
 			(status == 304) ? 0x8b :
 			(status == 206) ? 0x8a :
 		0:
 		(status <= 404) ?
 			(status == 404) ? 0x8d :
 			(status == 400) ? 0x8c :
 		0: /* > 404 */
 			(status == 500) ? 0x8e :
 		0;

 	if (c)
 		goto last;

 	/* fall back to literal */
 	len += 4;
 	if (__builtin_expect(len > size, 0))
 		goto fail;

 	/* basic encoding of the status code */
 	out->area[len - 5] = 0x48; // indexed name -- name=":status" (idx 8)
 	out->area[len - 4] = 0x03; // 3 bytes status
 	out->area[len - 3] = '0' + status / 100;
 	out->area[len - 2] = '0' + status / 10 % 10;
 	c = '0' + status % 10;
  last:
 	out->area[len - 1] = c;
 	out->data = len;
 	return 1;
  fail:
 	return 0;
 }

 /* Tries to encode a :status pseudo-header with the integer status <status>
  * also represented by <str> into the aligned buffer <out>. Returns non-zero
  * on success or 0 on failure (buffer full). The caller is responsible for
  * ensuring that the status is comprised between 100 and 999 inclusive, that
  * <str> contains a valid representation of the numerical value, and that the
  * buffer is aligned. This version is preferred when the caller already knows
  * a string representation of the status because it avoids the computation in
  * the uncompressed case. It's inlined because it's easily optimizable.
  */
 static inline int hpack_encode_str_status(struct buffer *out, unsigned int status, struct ist str)
 {
 	/* don't try too hard, we already have the ASCII value for less common cases */
 	if (status == 200 || status == 304) {
 		if (out->data >= out->size)
 			return 0;
 		out->area[out->data] = (status == 304) ? 0x8b : 0x88;
 		out->data++;
 		return 1;
 	}
 	return hpack_encode_short_idx(out, 8, str); // name=":status" (idx 8)
 }

 /* Tries to encode a :method pseudo-header with the method in <meth>, which
  * also exists as a string in <str>, into the aligned buffer <out>. Returns
  * non-zero on success or 0 on failure (buffer full). The caller is responsible
  * for ensuring that the string matches <meth>, that it's smaller than 127
  * bytes, and that the buffer is aligned. If <meth> is unknown then using
  * HTTP_METH_OTHER will lead to the string being encoded as a literal. It's
  * inlined because it's easily optimizable.
  */
 static inline int hpack_encode_method(struct buffer *out, enum http_meth_t meth, struct ist str)
 {
 	if (out->data < out->size && meth == HTTP_METH_GET)
 		out->area[out->data++] = 0x82; // indexed field : idx[02]=(":method", "GET")
 	else if (out->data < out->size && meth == HTTP_METH_POST)
 		out->area[out->data++] = 0x83; // indexed field : idx[03]=(":method", "POST")
 	else
 		return hpack_encode_short_idx(out, 2, str); // name=":method" (idx 2)
 	return 1;
 }

 /* Tries to encode a :scheme pseudo-header with the scheme in <scheme>, into
  * the aligned buffer <out>. Returns non-zero on success or 0 on failure
  * (buffer full). Only "http" and "https" are recognized and handled as indexed
  * values, others are turned into short literals. The caller is responsible for
  * ensuring that the scheme is smaller than 127 bytes, and that the buffer is
  * aligned. Normally the compiler will detect constant strings in the comparison
  * if the code remains inlined.
  */
 static inline int hpack_encode_scheme(struct buffer *out, struct ist scheme)
 {
 	if (out->data < out->size && isteq(scheme, ist("https")))
 		out->area[out->data++] = 0x87; // indexed field : idx[07]=(":scheme", "https")
 	else if (out->data < out->size && isteq(scheme, ist("http")))
 		out->area[out->data++] = 0x86; // indexed field : idx[06]=(":scheme", "http")
 	else
 		return hpack_encode_short_idx(out, 6, scheme); // name=":scheme" (idx 6)
 	return 1;
 }

 /* Tries to encode a :path pseudo-header with the path in <path>, into the
  * aligned buffer <out>. Returns non-zero on success or 0 on failure (buffer
  * full). The well-known values "/" and "/index.html" are recognized, and other
  * ones are handled as literals. The caller is responsible for ensuring that
  * the buffer is aligned.  Normally the compiler will detect constant strings
  * in the comparison if the code remains inlined.
  */
 static inline int hpack_encode_path(struct buffer *out, struct ist path)
 {
 	if (out->data < out->size && isteq(path, ist("/")))
 		out->area[out->data++] = 0x84; // indexed field : idx[04]=(":path", "/")
 	else if (out->data < out->size && isteq(path, ist("/index.html")))
 		out->area[out->data++] = 0x85; // indexed field : idx[05]=(":path", "/index.html")
 	else if (path.len < 127)
 		return hpack_encode_short_idx(out, 4, path); // name=":path" (idx 4)
 	else
 		return hpack_encode_long_idx(out, 4, path); // name=":path" (idx 4)
 	return 1;
 }


 #endif /* _COMMON_HPACK_ENC_H */
	/*
	* HPACK compressor (RFC7541)
	*
	* Copyright (C) 2014-2017 Willy Tarreau <willy@haproxy.org>
	* Copyright (C) 2017 HAProxy Technologies
	*
	* Permission is hereby granted, free of charge, to any person obtaining
	* a copy of this software and associated documentation files (the
	* "Software"), to deal in the Software without restriction, including
	* without limitation the rights to use, copy, modify, merge, publish,
	* distribute, sublicense, and/or sell copies of the Software, and to
	* permit persons to whom the Software is furnished to do so, subject to
	* the following conditions:
	*
	* The above copyright notice and this permission notice shall be
	* included in all copies or substantial portions of the Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
	* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
	* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
	* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
	* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
	* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
	* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
	* OTHER DEALINGS IN THE SOFTWARE.
	*/

	#ifndef _COMMON_HPACK_ENC_H
	#define _COMMON_HPACK_ENC_H

	#include <inttypes.h>
	#include <string.h>
	#include <common/buf.h>
	#include <common/config.h>
	#include <common/http.h>
	#include <common/ist.h>

	int hpack_encode_header(struct buffer *out, const struct ist n,
	const struct ist v);

	/* Returns the number of bytes required to encode the string length <len>. The
	* number of usable bits is an integral multiple of 7 plus 6 for the last byte.
	* The maximum number of bytes returned is 4 (2097279 max length). Larger values
	* return 0.
	*/
	static inline int hpack_len_to_bytes(size_t len)
	{
	ssize_t slen = len;

	slen -= 127;
	if (__builtin_expect(slen < 0, 1))
	return 1;
	if (slen < (1 << 14)) {
	if (__builtin_expect(slen < (1 << 7), 1))
	return 2;
	else
	return 3;
	}
	if (slen < (1 << 21))
	return 4;
	return 0;
	}

	/* Encodes <len> into <out>+<pos> and return the new position. The caller is
	* responsible for checking for available room using hpack_len_to_bytes()
	* first.
	*/
	static inline int hpack_encode_len(char *out, int pos, int len)
	{
	int code = len - 127;

	if (code < 0) {
	out[pos++] = len;
	} else {
	out[pos++] = 127;
	for (; code >= 128; code >>= 7)
	out[pos++] = code \| 128;
	out[pos++] = code;
	}
	return pos;
	}

	/* Tries to encode header field index <idx> with short value <val> into the
	* aligned buffer <out>. Returns non-zero on success, 0 on failure (buffer
	* full). The caller is responsible for ensuring that the length of <val> is
	* strictly lower than 127, and that <idx> is lower than 64 (static list only),
	* and that the buffer is aligned (head==0).
	*/
	static inline int hpack_encode_short_idx(struct buffer *out, int idx, struct ist val)
	{
	if (out->data + 2 + val.len > out->size)
	return 0;

	/* literal header field with incremental indexing */
	out->area[out->data++] = idx \| 0x40;
	out->area[out->data++] = val.len;
	ist2bin(&out->area[out->data], val);
	out->data += val.len;
	return 1;
	}

	/* Tries to encode header field index <idx> with long value <val> into the
	* aligned buffer <out>. Returns non-zero on success, 0 on failure (buffer
	* full). The caller is responsible for ensuring <idx> is lower than 64 (static
	* list only), and that the buffer is aligned (head==0).
	*/
	static inline int hpack_encode_long_idx(struct buffer *out, int idx, struct ist val)
	{
	int len = out->data;

	if (!hpack_len_to_bytes(val.len) \|\|
	1 + len + hpack_len_to_bytes(val.len) + val.len > out->size)
	return 0;

	/* emit literal with indexing (7541#6.2.1) :
	* [ 0 \| 1 \| Index (6+) ]
	*/
	out->area[len++] = idx \| 0x40;
	len = hpack_encode_len(out->area, len, val.len);
	memcpy(out->area + len, val.ptr, val.len);
	len += val.len;

	out->data = len;
	return 1;
	}

	/* Tries to encode a :status pseudo-header with the integer status <status>
	* into the aligned buffer <out>. Returns non-zero on success, 0 on failure
	* (buffer full). The caller is responsible for ensuring that the status is
	* comprised between 100 and 999 inclusive and that the buffer is aligned. It's
	* inlined because it's easily optimizable by the compiler.
	*/
	static inline int hpack_encode_int_status(struct buffer *out, unsigned int status)
	{
	int len = out->data;
	int size = out->size;
	unsigned char c = 0;

	/* try to emit a single byte code */
	len++;
	if (__builtin_expect(len > size, 0))
	goto fail;

	c = (status <= 304) ?
	(status <= 204) ?
	(status == 204) ? 0x89 :
	(status == 200) ? 0x88 :
	0: /* > 204 */
	(status == 304) ? 0x8b :
	(status == 206) ? 0x8a :
	0:
	(status <= 404) ?
	(status == 404) ? 0x8d :
	(status == 400) ? 0x8c :
	0: /* > 404 */
	(status == 500) ? 0x8e :
	0;

	if (c)
	goto last;

	/* fall back to literal */
	len += 4;
	if (__builtin_expect(len > size, 0))
	goto fail;

	/* basic encoding of the status code */
	out->area[len - 5] = 0x48; // indexed name -- name=":status" (idx 8)
	out->area[len - 4] = 0x03; // 3 bytes status
	out->area[len - 3] = '0' + status / 100;
	out->area[len - 2] = '0' + status / 10 % 10;
	c = '0' + status % 10;
	last:
	out->area[len - 1] = c;
	out->data = len;
	return 1;
	fail:
	return 0;
	}

	/* Tries to encode a :status pseudo-header with the integer status <status>
	* also represented by <str> into the aligned buffer <out>. Returns non-zero
	* on success or 0 on failure (buffer full). The caller is responsible for
	* ensuring that the status is comprised between 100 and 999 inclusive, that
	* <str> contains a valid representation of the numerical value, and that the
	* buffer is aligned. This version is preferred when the caller already knows
	* a string representation of the status because it avoids the computation in
	* the uncompressed case. It's inlined because it's easily optimizable.
	*/
	static inline int hpack_encode_str_status(struct buffer *out, unsigned int status, struct ist str)
	{
	/* don't try too hard, we already have the ASCII value for less common cases */
	if (status == 200 \|\| status == 304) {
	if (out->data >= out->size)
	return 0;
	out->area[out->data] = (status == 304) ? 0x8b : 0x88;
	out->data++;
	return 1;
	}
	return hpack_encode_short_idx(out, 8, str); // name=":status" (idx 8)
	}

	/* Tries to encode a :method pseudo-header with the method in <meth>, which
	* also exists as a string in <str>, into the aligned buffer <out>. Returns
	* non-zero on success or 0 on failure (buffer full). The caller is responsible
	* for ensuring that the string matches <meth>, that it's smaller than 127
	* bytes, and that the buffer is aligned. If <meth> is unknown then using
	* HTTP_METH_OTHER will lead to the string being encoded as a literal. It's
	* inlined because it's easily optimizable.
	*/
	static inline int hpack_encode_method(struct buffer *out, enum http_meth_t meth, struct ist str)
	{
	if (out->data < out->size && meth == HTTP_METH_GET)
	out->area[out->data++] = 0x82; // indexed field : idx[02]=(":method", "GET")
	else if (out->data < out->size && meth == HTTP_METH_POST)
	out->area[out->data++] = 0x83; // indexed field : idx[03]=(":method", "POST")
	else
	return hpack_encode_short_idx(out, 2, str); // name=":method" (idx 2)
	return 1;
	}

	/* Tries to encode a :scheme pseudo-header with the scheme in <scheme>, into
	* the aligned buffer <out>. Returns non-zero on success or 0 on failure
	* (buffer full). Only "http" and "https" are recognized and handled as indexed
	* values, others are turned into short literals. The caller is responsible for
	* ensuring that the scheme is smaller than 127 bytes, and that the buffer is
	* aligned. Normally the compiler will detect constant strings in the comparison
	* if the code remains inlined.
	*/
	static inline int hpack_encode_scheme(struct buffer *out, struct ist scheme)
	{
	if (out->data < out->size && isteq(scheme, ist("https")))
	out->area[out->data++] = 0x87; // indexed field : idx[07]=(":scheme", "https")
	else if (out->data < out->size && isteq(scheme, ist("http")))
	out->area[out->data++] = 0x86; // indexed field : idx[06]=(":scheme", "http")
	else
	return hpack_encode_short_idx(out, 6, scheme); // name=":scheme" (idx 6)
	return 1;
	}

	/* Tries to encode a :path pseudo-header with the path in <path>, into the
	* aligned buffer <out>. Returns non-zero on success or 0 on failure (buffer
	* full). The well-known values "/" and "/index.html" are recognized, and other
	* ones are handled as literals. The caller is responsible for ensuring that
	* the buffer is aligned. Normally the compiler will detect constant strings
	* in the comparison if the code remains inlined.
	*/
	static inline int hpack_encode_path(struct buffer *out, struct ist path)
	{
	if (out->data < out->size && isteq(path, ist("/")))
	out->area[out->data++] = 0x84; // indexed field : idx[04]=(":path", "/")
	else if (out->data < out->size && isteq(path, ist("/index.html")))
	out->area[out->data++] = 0x85; // indexed field : idx[05]=(":path", "/index.html")
	else if (path.len < 127)
	return hpack_encode_short_idx(out, 4, path); // name=":path" (idx 4)
	else
	return hpack_encode_long_idx(out, 4, path); // name=":path" (idx 4)
	return 1;
	}


	#endif /* _COMMON_HPACK_ENC_H */