/* SPDX-License-Identifier: MIT */

/* Based on src/http/ngx_http_parse.c from NGINX copyright Igor Sysoev
 *
 * Additional changes are licensed under the same terms as NGINX and
 * copyright Joyent, Inc. and other Node contributors. All rights reserved.
 *
 * 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.
 */
#include <zephyr/sys/__assert.h>
#include <stddef.h>
#include <ctype.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include <zephyr/net/http/parser_url.h>
#include <zephyr/toolchain.h>

#ifndef BIT_AT
# define BIT_AT(a, i)                                                \
	(!!((unsigned int) (a)[(unsigned int) (i) >> 3] &                  \
	 (1 << ((unsigned int) (i) & 7))))
#endif

/* Set the mark FOR; non-destructive if mark is already set */
#define MARK(FOR)                                                          \
do {                                                                       \
	if (!FOR##_mark) {                                                 \
		FOR##_mark = p;                                            \
	}                                                                  \
} while (false)


#ifdef HTTP_PARSER_STRICT
# define T(v) 0
#else
# define T(v) v
#endif


static const uint8_t normal_url_char[32] = {
/*   0 nul    1 soh    2 stx    3 etx    4 eot    5 enq    6 ack    7 bel  */
	0    |   0    |   0    |   0    |   0    |   0    |   0    |   0,
/*   8 bs     9 ht    10 nl    11 vt    12 np    13 cr    14 so    15 si   */
	0    | T(2)   |   0    |   0    | T(16)  |   0    |   0    |   0,
/*  16 dle   17 dc1   18 dc2   19 dc3   20 dc4   21 nak   22 syn   23 etb */
	0    |   0    |   0    |   0    |   0    |   0    |   0    |   0,
/*  24 can   25 em    26 sub   27 esc   28 fs    29 gs    30 rs    31 us  */
	0    |   0    |   0    |   0    |   0    |   0    |   0    |   0,
/*  32 sp    33  !    34  "    35  #    36  $    37  %    38  &    39  '  */
	0    |   2    |   4    |   0    |   16   |   32   |   64   |  128,
/*  40  (    41  )    42  *    43  +    44  ,    45  -    46  .    47  /  */
	1    |   2    |   4    |   8    |   16   |   32   |   64   |  128,
/*  48  0    49  1    50  2    51  3    52  4    53  5    54  6    55  7  */
	1    |   2    |   4    |   8    |   16   |   32   |   64   |  128,
/*  56  8    57  9    58  :    59  ;    60  <    61  =    62  >    63  ?  */
	1    |   2    |   4    |   8    |   16   |   32   |   64   |   0,
/*  64  @    65  A    66  B    67  C    68  D    69  E    70  F    71  G  */
	1    |   2    |   4    |   8    |   16   |   32   |   64   |  128,
/*  72  H    73  I    74  J    75  K    76  L    77  M    78  N    79  O  */
	1    |   2    |   4    |   8    |   16   |   32   |   64   |  128,
/*  80  P    81  Q    82  R    83  S    84  T    85  U    86  V    87  W  */
	1    |   2    |   4    |   8    |   16   |   32   |   64   |  128,
/*  88  X    89  Y    90  Z    91  [    92  \    93  ]    94  ^    95  _  */
	1    |   2    |   4    |   8    |   16   |   32   |   64   |  128,
/*  96  `    97  a    98  b    99  c   100  d   101  e   102  f   103  g  */
	1    |   2    |   4    |   8    |   16   |   32   |   64   |  128,
/* 104  h   105  i   106  j   107  k   108  l   109  m   110  n   111  o  */
	1    |   2    |   4    |   8    |   16   |   32   |   64   |  128,
/* 112  p   113  q   114  r   115  s   116  t   117  u   118  v   119  w  */
	1    |   2    |   4    |   8    |   16   |   32   |   64   |  128,
/* 120  x   121  y   122  z   123  {   124  |   125  }   126  ~   127 del */
	1    |   2    |   4    |   8    |   16   |   32   |   64   |   0,
};

#undef T

enum http_host_state {
	s_http_host_dead = 1,
	s_http_userinfo_start,
	s_http_userinfo,
	s_http_host_start,
	s_http_host_v6_start,
	s_http_host,
	s_http_host_v6,
	s_http_host_v6_end,
	s_http_host_v6_zone_start,
	s_http_host_v6_zone,
	s_http_host_port_start,
	s_http_host_port
};


/* Macros for character classes; depends on strict-mode  */
#define LOWER(c)            (unsigned char)(c | 0x20)
#define IS_ALPHA(c)         (LOWER(c) >= 'a' && LOWER(c) <= 'z')
#define IS_NUM(c)           ((c) >= '0' && (c) <= '9')
#define IS_ALPHANUM(c)      (IS_ALPHA(c) || IS_NUM(c))
#define IS_HEX(c)           (IS_NUM(c) || (LOWER(c) >= 'a' && LOWER(c) <= 'f'))

#define IS_MARK(c)		((c) == '-' || (c) == '_' || (c) == '.' || \
				 (c) == '!' || (c) == '~' || (c) == '*' || \
				 (c) == '\'' || (c) == '(' || (c) == ')')

#define IS_USERINFO_CHAR(c) (IS_ALPHANUM(c) || IS_MARK(c) || (c) == '%' || \
				(c) == ';' || (c) == ':' || (c) == '&' ||  \
				(c) == '=' || (c) == '+' || (c) == '$' ||  \
				(c) == ',')

#ifdef HTTP_PARSER_STRICT
#define IS_URL_CHAR(c)      (BIT_AT(normal_url_char, (unsigned char)c))
#define IS_HOST_CHAR(c)     (IS_ALPHANUM(c) || (c) == '.' || (c) == '-')
#else
#define IS_URL_CHAR(c)                                                         \
	(BIT_AT(normal_url_char, (unsigned char)c) || ((c) & 0x80))
#define IS_HOST_CHAR(c)                                                        \
	(IS_ALPHANUM(c) || (c) == '.' || (c) == '-' || (c) == '_')
#endif

/* Our URL parser.
 *
 * This is designed to be shared by http_parser_execute() for URL validation,
 * hence it has a state transition + byte-for-byte interface. In addition, it
 * is meant to be embedded in http_parser_parse_url(), which does the dirty
 * work of turning state transitions URL components for its API.
 *
 * This function should only be invoked with non-space characters. It is
 * assumed that the caller cares about (and can detect) the transition between
 * URL and non-URL states by looking for these.
 */
enum state parse_url_char(enum state s, const char ch)
{
	if (ch == ' ' || ch == '\r' || ch == '\n') {
		return s_dead;
	}

#ifdef HTTP_PARSER_STRICT
	if (ch == '\t' || ch == '\f') {
		return s_dead;
	}
#endif

	switch (s) {
	case s_req_spaces_before_url:
		/* Proxied requests are followed by scheme of an absolute URI
		 * (alpha).
		 * All methods except CONNECT are followed by '/' or '*'.
		 */

		if (ch == '/' || ch == '*') {
			return s_req_path;
		}

		if (IS_ALPHA(ch)) {
			return s_req_schema;
		}

		break;

	case s_req_schema:
		if (IS_ALPHA(ch)) {
			return s;
		}

		if (ch == ':') {
			return s_req_schema_slash;
		}

		break;

	case s_req_schema_slash:
		if (ch == '/') {
			return s_req_schema_slash_slash;
		}

		break;

	case s_req_schema_slash_slash:
		if (ch == '/') {
			return s_req_server_start;
		}

		break;

	case s_req_server_with_at:
		if (ch == '@') {
			return s_dead;
		}

		__fallthrough;
	case s_req_server_start:
	case s_req_server:
		if (ch == '/') {
			return s_req_path;
		}

		if (ch == '?') {
			return s_req_query_string_start;
		}

		if (ch == '@') {
			return s_req_server_with_at;
		}

		if (IS_USERINFO_CHAR(ch) || ch == '[' || ch == ']') {
			return s_req_server;
		}

		break;

	case s_req_path:
		if (IS_URL_CHAR(ch)) {
			return s;
		}

		switch (ch) {
		case '?':
			return s_req_query_string_start;

		case '#':
			return s_req_fragment_start;
		}

		break;

	case s_req_query_string_start:
	case s_req_query_string:
		if (IS_URL_CHAR(ch)) {
			return s_req_query_string;
		}

		switch (ch) {
		case '?':
			/* allow extra '?' in query string */
			return s_req_query_string;

		case '#':
			return s_req_fragment_start;
		}

		break;

	case s_req_fragment_start:
		if (IS_URL_CHAR(ch)) {
			return s_req_fragment;
		}

		switch (ch) {
		case '?':
			return s_req_fragment;

		case '#':
			return s;
		}

		break;

	case s_req_fragment:
		if (IS_URL_CHAR(ch)) {
			return s;
		}

		switch (ch) {
		case '?':
		case '#':
			return s;
		}

		break;

	default:
		break;
	}

	/* We should never fall out of the switch above unless there's
	 * an error
	 */
	return s_dead;
}

static enum http_host_state
http_parse_host_char(enum http_host_state s, const char ch)
{
	switch (s) {
	case s_http_userinfo:
	case s_http_userinfo_start:
		if (ch == '@') {
			return s_http_host_start;
		}

		if (IS_USERINFO_CHAR(ch)) {
			return s_http_userinfo;
		}
		break;

	case s_http_host_start:
		if (ch == '[') {
			return s_http_host_v6_start;
		}

		if (IS_HOST_CHAR(ch)) {
			return s_http_host;
		}

		break;

	case s_http_host:
		if (IS_HOST_CHAR(ch)) {
			return s_http_host;
		}

		__fallthrough;
	case s_http_host_v6_end:
		if (ch == ':') {
			return s_http_host_port_start;
		}

		break;

	case s_http_host_v6:
		if (ch == ']') {
			return s_http_host_v6_end;
		}

		__fallthrough;
	case s_http_host_v6_start:
		if (IS_HEX(ch) || ch == ':' || ch == '.') {
			return s_http_host_v6;
		}

		if (s == s_http_host_v6 && ch == '%') {
			return s_http_host_v6_zone_start;
		}
		break;

	case s_http_host_v6_zone:
		if (ch == ']') {
			return s_http_host_v6_end;
		}

		__fallthrough;
	case s_http_host_v6_zone_start:
		/* RFC 6874 Zone ID consists of 1*( unreserved / pct-encoded) */
		if (IS_ALPHANUM(ch) || ch == '%' || ch == '.' || ch == '-' ||
				ch == '_' ||
				ch == '~') {
			return s_http_host_v6_zone;
		}
		break;

	case s_http_host_port:
	case s_http_host_port_start:
		if (IS_NUM(ch)) {
			return s_http_host_port;
		}

		break;

	default:
		break;
	}
	return s_http_host_dead;
}

static
int http_parse_host(const char *buf, struct http_parser_url *u,
		    int found_at)
{
	enum http_host_state s;
	size_t buflen;
	const char *p;

	buflen = u->field_data[UF_HOST].off + u->field_data[UF_HOST].len;
	__ASSERT_NO_MSG(u->field_set & (1 << UF_HOST));

	u->field_data[UF_HOST].len = 0U;

	s = found_at ? s_http_userinfo_start : s_http_host_start;

	for (p = buf + u->field_data[UF_HOST].off; p < buf + buflen; p++) {
		enum http_host_state new_s = http_parse_host_char(s, *p);

		if (new_s == s_http_host_dead) {
			return 1;
		}

		switch (new_s) {
		case s_http_host:
			if (s != s_http_host) {
				u->field_data[UF_HOST].off = p - buf;
			}
			u->field_data[UF_HOST].len++;
			break;

		case s_http_host_v6:
			if (s != s_http_host_v6) {
				u->field_data[UF_HOST].off = p - buf;
			}
			u->field_data[UF_HOST].len++;
			break;

		case s_http_host_v6_zone_start:
		case s_http_host_v6_zone:
			u->field_data[UF_HOST].len++;
			break;

		case s_http_host_port:
			if (s != s_http_host_port) {
				u->field_data[UF_PORT].off = p - buf;
				u->field_data[UF_PORT].len = 0U;
				u->field_set |= (1 << UF_PORT);
			}
			u->field_data[UF_PORT].len++;
			break;

		case s_http_userinfo:
			if (s != s_http_userinfo) {
				u->field_data[UF_USERINFO].off = p - buf;
				u->field_data[UF_USERINFO].len = 0U;
				u->field_set |= (1 << UF_USERINFO);
			}
			u->field_data[UF_USERINFO].len++;
			break;

		default:
			break;
		}
		s = new_s;
	}

	/* Make sure we don't end somewhere unexpected */
	switch (s) {
	case s_http_host_start:
	case s_http_host_v6_start:
	case s_http_host_v6:
	case s_http_host_v6_zone_start:
	case s_http_host_v6_zone:
	case s_http_host_port_start:
	case s_http_userinfo:
	case s_http_userinfo_start:
		return 1;
	default:
		break;
	}

	return 0;
}

void
http_parser_url_init(struct http_parser_url *u)
{
	(void)memset(u, 0, sizeof(*u));
}

int
http_parser_parse_url(const char *buf, size_t buflen, int is_connect,
		      struct http_parser_url *u)
{
	enum http_parser_url_fields old_uf;
	enum http_parser_url_fields uf;
	int found_at = 0;
	const char *p;
	enum state s;

	u->port = u->field_set = 0U;
	s = is_connect ? s_req_server_start : s_req_spaces_before_url;
	old_uf = UF_MAX;

	for (p = buf; p < buf + buflen; p++) {
		s = parse_url_char(s, *p);

		/* Figure out the next field that we're operating on */
		switch (s) {
		case s_dead:
			return 1;

		/* Skip delimiters */
		case s_req_schema_slash:
		case s_req_schema_slash_slash:
		case s_req_server_start:
		case s_req_query_string_start:
		case s_req_fragment_start:
			continue;

		case s_req_schema:
			uf = UF_SCHEMA;
			break;

		case s_req_server_with_at:
			found_at = 1;
			__fallthrough;

		case s_req_server:
			uf = UF_HOST;
			break;

		case s_req_path:
			uf = UF_PATH;
			break;

		case s_req_query_string:
			uf = UF_QUERY;
			break;

		case s_req_fragment:
			uf = UF_FRAGMENT;
			break;

		default:
			__ASSERT_NO_MSG(!"Unexpected state");
			return 1;
		}

		/* Nothing's changed; soldier on */
		if (uf == old_uf) {
			u->field_data[uf].len++;
			continue;
		}

		u->field_data[uf].off = p - buf;
		u->field_data[uf].len = 1U;

		u->field_set |= (1 << uf);
		old_uf = uf;
	}

	/* host must be present if there is a schema */
	/* parsing http:///toto will fail */
	if ((u->field_set & (1 << UF_SCHEMA)) &&
			(u->field_set & (1 << UF_HOST)) == 0U) {
		return 1;
	}

	if (u->field_set & (1 << UF_HOST)) {
		if (http_parse_host(buf, u, found_at) != 0) {
			return 1;
		}
	}

	/* CONNECT requests can only contain "hostname:port" */
	if (is_connect && u->field_set != ((1 << UF_HOST)|(1 << UF_PORT))) {
		return 1;
	}

	if (u->field_set & (1 << UF_PORT)) {
		/* Don't bother with endp; we've already validated the string */
		unsigned long v;

		v = strtoul(buf + u->field_data[UF_PORT].off, NULL, 10);

		/* Ports have a max value of 2^16 */
		if (v > 0xffff) {
			return 1;
		}

		u->port = (uint16_t) v;
	}

	return 0;
}