/***************************************************************************

 *                                  _   _ ____  _

 *  Project                     ___| | | |  _ \| |

 *                             / __| | | | |_) | |

 *                            | (__| |_| |  _ <| |___

 *                             \___|\___/|_| \_\_____|

 *

 * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.

 *

 * This software is licensed as described in the file COPYING, which

 * you should have received as part of this distribution. The terms

 * are also available at https://curl.se/docs/copyright.html.

 *

 * You may opt to use, copy, modify, merge, publish, distribute and/or sell

 * copies of the Software, and permit persons to whom the Software is

 * furnished to do so, under the terms of the COPYING file.

 *

 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY

 * KIND, either express or implied.

 *

 * SPDX-License-Identifier: curl

 *

 ***************************************************************************/

#include "curl_setup.h"

#ifndef CURL_DISABLE_PROXY

#include "curlx/inet_pton.h"

#include "noproxy.h"

#include "curlx/strparse.h"

#ifdef HAVE_NETINET_IN_H

#include <netinet/in.h>

#endif

#ifdef HAVE_ARPA_INET_H

#include <arpa/inet.h>

#endif

/*

 * Curl_cidr4_match() returns TRUE if the given IPv4 address is within the

 * specified CIDR address range.

 */

UNITTEST bool Curl_cidr4_match(const char *ipv4,    /* 1.2.3.4 address */

                               const char *network, /* 1.2.3.4 address */

                               unsigned int bits);

UNITTEST bool Curl_cidr4_match(const char *ipv4,    /* 1.2.3.4 address */

                               const char *network, /* 1.2.3.4 address */

                               unsigned int bits)

{

  unsigned int address = 0;

  unsigned int check = 0;

  if(bits > 32)

    /* strange input */

    return FALSE;

  if(curlx_inet_pton(AF_INET, ipv4, &address) != 1)

    return FALSE;

  if(curlx_inet_pton(AF_INET, network, &check) != 1)

    return FALSE;

  if(bits && (bits != 32)) {

    unsigned int mask = 0xffffffff << (32 - bits);

    unsigned int haddr = htonl(address);

    unsigned int hcheck = htonl(check);

#if 0

    curl_mfprintf(stderr, "Host %s (%x) network %s (%x) "

                  "bits %u mask %x => %x\n",

                  ipv4, haddr, network, hcheck, bits, mask,

                  (haddr ^ hcheck) & mask);

#endif

    if((haddr ^ hcheck) & mask)

      return FALSE;

    return TRUE;

  }

  return address == check;

}

UNITTEST bool Curl_cidr6_match(const char *ipv6,

                               const char *network,

                               unsigned int bits);

UNITTEST bool Curl_cidr6_match(const char *ipv6,

                               const char *network,

                               unsigned int bits)

{

#ifdef USE_IPV6

  unsigned int bytes;

  unsigned int rest;

  unsigned char address[16];

  unsigned char check[16];

  if(!bits)

    bits = 128;

  bytes = bits / 8;

  rest = bits & 0x07;

  if((bytes > 16) || ((bytes == 16) && rest))

    return FALSE;

  if(curlx_inet_pton(AF_INET6, ipv6, address) != 1)

    return FALSE;

  if(curlx_inet_pton(AF_INET6, network, check) != 1)

    return FALSE;

  if(bytes && memcmp(address, check, bytes))

    return FALSE;

  if(rest && ((address[bytes] ^ check[bytes]) & (0xff << (8 - rest))))

    return FALSE;

  return TRUE;

#else

  (void)ipv6;

  (void)network;

  (void)bits;

  return FALSE;

#endif

}

enum nametype {

  TYPE_HOST,

  TYPE_IPV4,

  TYPE_IPV6

};

static bool match_host(const char *token, size_t tokenlen,

                       const char *name, size_t namelen)

{

  bool match = FALSE;

  /* ignore trailing dots in the token to check */

  if(token[tokenlen - 1] == '.')

    tokenlen--;

  if(tokenlen && (*token == '.')) {

    /* ignore leading token dot as well */

    token++;

    tokenlen--;

  }

  /* A: example.com matches 'example.com'

     B: www.example.com matches 'example.com'

     C: nonexample.com DOES NOT match 'example.com'

  */

  if(tokenlen == namelen)

    /* case A, exact match */

    match = curl_strnequal(token, name, namelen);

  else if(tokenlen < namelen) {

    /* case B, tailmatch domain */

    match = (name[namelen - tokenlen - 1] == '.') &&

            curl_strnequal(token, name + (namelen - tokenlen), tokenlen);

  }

  /* case C passes through, not a match */

  return match;

}

static bool match_ip(int type, const char *token, size_t tokenlen,

                     const char *name)

{

  char *slash;

  unsigned int bits = 0;

  char checkip[128];

  if(tokenlen >= sizeof(checkip))

    /* this cannot match */

    return FALSE;

  /* copy the check name to a temp buffer */

  memcpy(checkip, token, tokenlen);

  checkip[tokenlen] = 0;

  slash = strchr(checkip, '/');

  /* if the slash is part of this token, use it */

  if(slash) {

    curl_off_t value;

    const char *p = &slash[1];

    if(curlx_str_number(&p, &value, 128) || *p)

      return FALSE;

    /* a too large value is rejected in the cidr function below */

    bits = (unsigned int)value;

    *slash = 0; /* null-terminate there */

  }

  if(type == TYPE_IPV6)

    return Curl_cidr6_match(name, checkip, bits);

  else

    return Curl_cidr4_match(name, checkip, bits);

}

/****************************************************************

 * Checks if the host is in the noproxy list. returns TRUE if it matches and

 * therefore the proxy should NOT be used.

 ****************************************************************/

bool Curl_check_noproxy(const char *name, const char *no_proxy)

{

  /*

   * If we do not have a hostname at all, like for example with a FILE

   * transfer, we have nothing to interrogate the noproxy list with.

   */

  if(!name || name[0] == '\0')

    return FALSE;

  /* no_proxy=domain1.dom,host.domain2.dom

   *   (a comma-separated list of hosts which should

   *   not be proxied, or an asterisk to override

   *   all proxy variables)

   */

  if(no_proxy && no_proxy[0]) {

    const char *p = no_proxy;

    size_t namelen;

    char address[16];

    enum nametype type = TYPE_HOST;

    if(!strcmp("*", no_proxy))

      return TRUE;

    /* NO_PROXY was specified and it was not only an asterisk */

    /* Check if name is an IP address; if not, assume it being a hostname. */

    namelen = strlen(name);

    if(curlx_inet_pton(AF_INET, name, &address) == 1)

      type = TYPE_IPV4;

#ifdef USE_IPV6

    else if(curlx_inet_pton(AF_INET6, name, &address) == 1)

      type = TYPE_IPV6;

#endif

    else {

      /* ignore trailing dots in the hostname */

      if(name[namelen - 1] == '.')

        namelen--;

    }

    while(*p) {

      const char *token;

      size_t tokenlen = 0;

      /* pass blanks */

      curlx_str_passblanks(&p);

      token = p;

      /* pass over the pattern */

      while(*p && !ISBLANK(*p) && (*p != ',')) {

        p++;

        tokenlen++;

      }

      if(tokenlen) {

        bool match = FALSE;

        if(type == TYPE_HOST)

          match = match_host(token, tokenlen, name, namelen);

        else

          match = match_ip(type, token, tokenlen, name);

        if(match)

          return TRUE;

      }

      /* pass blanks after pattern */

      curlx_str_passblanks(&p);

      /* if not a comma, this ends the loop */

      if(*p != ',')

        break;

      /* pass any number of commas */

      while(*p == ',')

        p++;

    } /* while(*p) */

  } /* NO_PROXY was specified and it was not only an asterisk */

  return FALSE;

}

#endif /* CURL_DISABLE_PROXY */