/*-------------------------------------------------------------------------

 *

 * ifaddr.c

 *    IP netmask calculations, and enumerating network interfaces.

 *

 * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group

 * Portions Copyright (c) 1994, Regents of the University of California

 *

 *

 * IDENTIFICATION

 *    src/backend/libpq/ifaddr.c

 *

 * This file and the IPV6 implementation were initially provided by

 * Nigel Kukard <nkukard@lbsd.net>, Linux Based Systems Design

 * http://www.lbsd.net.

 *

 *-------------------------------------------------------------------------

 */

#include "postgres.h"

#include <unistd.h>

#include <sys/stat.h>

#include <sys/socket.h>

#include <netdb.h>

#include <netinet/in.h>

#include <netinet/tcp.h>

#include <sys/file.h>

#include "libpq/ifaddr.h"

#include "port/pg_bswap.h"

static int  range_sockaddr_AF_INET(const struct sockaddr_in *addr,

                   const struct sockaddr_in *netaddr,

                   const struct sockaddr_in *netmask);

static int  range_sockaddr_AF_INET6(const struct sockaddr_in6 *addr,

                  const struct sockaddr_in6 *netaddr,

                  const struct sockaddr_in6 *netmask);

/*

 * pg_range_sockaddr - is addr within the subnet specified by netaddr/netmask ?

 *

 * Note: caller must already have verified that all three addresses are

 * in the same address family; and AF_UNIX addresses are not supported.

 */

int

pg_range_sockaddr(const struct sockaddr_storage *addr,

          const struct sockaddr_storage *netaddr,

          const struct sockaddr_storage *netmask)

{

  if (addr->ss_family == AF_INET)

    return range_sockaddr_AF_INET((const struct sockaddr_in *) addr,

                    (const struct sockaddr_in *) netaddr,

                    (const struct sockaddr_in *) netmask);

  else if (addr->ss_family == AF_INET6)

    return range_sockaddr_AF_INET6((const struct sockaddr_in6 *) addr,

                     (const struct sockaddr_in6 *) netaddr,

                     (const struct sockaddr_in6 *) netmask);

  else

    return 0;

}

static int

range_sockaddr_AF_INET(const struct sockaddr_in *addr,

             const struct sockaddr_in *netaddr,

             const struct sockaddr_in *netmask)

{

  if (((addr->sin_addr.s_addr ^ netaddr->sin_addr.s_addr) &

     netmask->sin_addr.s_addr) == 0)

    return 1;

  else

    return 0;

}

static int

range_sockaddr_AF_INET6(const struct sockaddr_in6 *addr,

            const struct sockaddr_in6 *netaddr,

            const struct sockaddr_in6 *netmask)

{

  int     i;

  for (i = 0; i < 16; i++)

  {

    if (((addr->sin6_addr.s6_addr[i] ^ netaddr->sin6_addr.s6_addr[i]) &

       netmask->sin6_addr.s6_addr[i]) != 0)

      return 0;

  }

  return 1;

}

/*

 *  pg_sockaddr_cidr_mask - make a network mask of the appropriate family

 *    and required number of significant bits

 *

 * numbits can be null, in which case the mask is fully set.

 *

 * The resulting mask is placed in *mask, which had better be big enough.

 *

 * Return value is 0 if okay, -1 if not.

 */

int

pg_sockaddr_cidr_mask(struct sockaddr_storage *mask, char *numbits, int family)

{

  long    bits;

  char     *endptr;

  if (numbits == NULL)

  {

    bits = (family == AF_INET) ? 32 : 128;

  }

  else

  {

    bits = strtol(numbits, &endptr, 10);

    if (*numbits == '\0' || *endptr != '\0')

      return -1;

  }

  switch (family)

  {

    case AF_INET:

      {

        struct sockaddr_in mask4;

        long    maskl;

        if (bits < 0 || bits > 32)

          return -1;

        memset(&mask4, 0, sizeof(mask4));

        /* avoid "x << 32", which is not portable */

        if (bits > 0)

          maskl = (0xffffffffUL << (32 - (int) bits))

            & 0xffffffffUL;

        else

          maskl = 0;

        mask4.sin_addr.s_addr = pg_hton32(maskl);

        memcpy(mask, &mask4, sizeof(mask4));

        break;

      }

    case AF_INET6:

      {

        struct sockaddr_in6 mask6;

        int     i;

        if (bits < 0 || bits > 128)

          return -1;

        memset(&mask6, 0, sizeof(mask6));

        for (i = 0; i < 16; i++)

        {

          if (bits <= 0)

            mask6.sin6_addr.s6_addr[i] = 0;

          else if (bits >= 8)

            mask6.sin6_addr.s6_addr[i] = 0xff;

          else

          {

            mask6.sin6_addr.s6_addr[i] =

              (0xff << (8 - (int) bits)) & 0xff;

          }

          bits -= 8;

        }

        memcpy(mask, &mask6, sizeof(mask6));

        break;

      }

    default:

      return -1;

  }

  mask->ss_family = family;

  return 0;

}

/*

 * Run the callback function for the addr/mask, after making sure the

 * mask is sane for the addr.

 */

static void

run_ifaddr_callback(PgIfAddrCallback callback, void *cb_data,

          struct sockaddr *addr, struct sockaddr *mask)

{

  struct sockaddr_storage fullmask;

  if (!addr)

    return;

  /* Check that the mask is valid */

  if (mask)

  {

    if (mask->sa_family != addr->sa_family)

    {

      mask = NULL;

    }

    else if (mask->sa_family == AF_INET)

    {

      if (((struct sockaddr_in *) mask)->sin_addr.s_addr == INADDR_ANY)

        mask = NULL;

    }

    else if (mask->sa_family == AF_INET6)

    {

      if (IN6_IS_ADDR_UNSPECIFIED(&((struct sockaddr_in6 *) mask)->sin6_addr))

        mask = NULL;

    }

  }

  /* If mask is invalid, generate our own fully-set mask */

  if (!mask)

  {

    pg_sockaddr_cidr_mask(&fullmask, NULL, addr->sa_family);

    mask = (struct sockaddr *) &fullmask;

  }

  (*callback) (addr, mask, cb_data);

}

#ifdef WIN32

#include <winsock2.h>

#include <ws2tcpip.h>

/*

 * Enumerate the system's network interface addresses and call the callback

 * for each one.  Returns 0 if successful, -1 if trouble.

 *

 * This version is for Win32.  Uses the Winsock 2 functions (ie: ws2_32.dll)

 */

int

pg_foreach_ifaddr(PgIfAddrCallback callback, void *cb_data)

{

  INTERFACE_INFO *ptr,

         *ii = NULL;

  unsigned long length,

        i;

  unsigned long n_ii = 0;

  SOCKET    sock;

  int     error;

  sock = WSASocket(AF_INET, SOCK_DGRAM, 0, 0, 0, 0);

  if (sock == INVALID_SOCKET)

    return -1;

  while (n_ii < 1024)

  {

    n_ii += 64;

    ptr = realloc(ii, sizeof(INTERFACE_INFO) * n_ii);

    if (!ptr)

    {

      free(ii);

      closesocket(sock);

      errno = ENOMEM;

      return -1;

    }

    ii = ptr;

    if (WSAIoctl(sock, SIO_GET_INTERFACE_LIST, 0, 0,

           ii, n_ii * sizeof(INTERFACE_INFO),

           &length, 0, 0) == SOCKET_ERROR)

    {

      error = WSAGetLastError();

      if (error == WSAEFAULT || error == WSAENOBUFS)

        continue;   /* need to make the buffer bigger */

      closesocket(sock);

      free(ii);

      return -1;

    }

    break;

  }

  for (i = 0; i < length / sizeof(INTERFACE_INFO); ++i)

    run_ifaddr_callback(callback, cb_data,

              (struct sockaddr *) &ii[i].iiAddress,

              (struct sockaddr *) &ii[i].iiNetmask);

  closesocket(sock);

  free(ii);

  return 0;

}

#elif HAVE_GETIFADDRS     /* && !WIN32 */

#ifdef HAVE_IFADDRS_H

#include <ifaddrs.h>

#endif

/*

 * Enumerate the system's network interface addresses and call the callback

 * for each one.  Returns 0 if successful, -1 if trouble.

 *

 * This version uses the getifaddrs() interface, which is available on

 * BSDs, macOS, Solaris, illumos and Linux.

 */

int

pg_foreach_ifaddr(PgIfAddrCallback callback, void *cb_data)

{

  struct ifaddrs *ifa,

         *l;

  if (getifaddrs(&ifa) < 0)

    return -1;

  for (l = ifa; l; l = l->ifa_next)

    run_ifaddr_callback(callback, cb_data,

              l->ifa_addr, l->ifa_netmask);

  freeifaddrs(ifa);

  return 0;

}

#else             /* !HAVE_GETIFADDRS && !WIN32 */

#include <sys/ioctl.h>

#include <net/if.h>

#if defined(SIOCGIFCONF)

/*

 * Remaining Unixes use SIOCGIFCONF. Some only return IPv4 information

 * here, so this is the least preferred method. Note that there is no

 * standard way to iterate the struct ifreq returned in the array.

 * On some OSs the structures are padded large enough for any address,

 * on others you have to calculate the size of the struct ifreq.

 */

/* Some OSs have _SIZEOF_ADDR_IFREQ, so just use that */

#ifndef _SIZEOF_ADDR_IFREQ

/* Calculate based on sockaddr.sa_len */

#ifdef HAVE_STRUCT_SOCKADDR_SA_LEN

#define _SIZEOF_ADDR_IFREQ(ifr) \

    ((ifr).ifr_addr.sa_len > sizeof(struct sockaddr) ? \

     (sizeof(struct ifreq) - sizeof(struct sockaddr) + \

      (ifr).ifr_addr.sa_len) : sizeof(struct ifreq))

/* Padded ifreq structure, simple */

#else

#define _SIZEOF_ADDR_IFREQ(ifr) \

  sizeof (struct ifreq)

#endif

#endif              /* !_SIZEOF_ADDR_IFREQ */

/*

 * Enumerate the system's network interface addresses and call the callback

 * for each one.  Returns 0 if successful, -1 if trouble.

 *

 * This version uses ioctl(SIOCGIFCONF).

 */

int

pg_foreach_ifaddr(PgIfAddrCallback callback, void *cb_data)

{

  struct ifconf ifc;

  struct ifreq *ifr,

         *end,

        addr,

        mask;

  char     *ptr,

         *buffer = NULL;

  size_t    n_buffer = 1024;

  pgsocket  sock;

  sock = socket(AF_INET, SOCK_DGRAM, 0);

  if (sock == PGINVALID_SOCKET)

    return -1;

  while (n_buffer < 1024 * 100)

  {

    n_buffer += 1024;

    ptr = realloc(buffer, n_buffer);

    if (!ptr)

    {

      free(buffer);

      close(sock);

      errno = ENOMEM;

      return -1;

    }

    memset(&ifc, 0, sizeof(ifc));

    ifc.ifc_buf = buffer = ptr;

    ifc.ifc_len = n_buffer;

    if (ioctl(sock, SIOCGIFCONF, &ifc) < 0)

    {

      if (errno == EINVAL)

        continue;

      free(buffer);

      close(sock);

      return -1;

    }

    /*

     * Some Unixes try to return as much data as possible, with no

     * indication of whether enough space allocated. Don't believe we have

     * it all unless there's lots of slop.

     */

    if (ifc.ifc_len < n_buffer - 1024)

      break;

  }

  end = (struct ifreq *) (buffer + ifc.ifc_len);

  for (ifr = ifc.ifc_req; ifr < end;)

  {

    memcpy(&addr, ifr, sizeof(addr));

    memcpy(&mask, ifr, sizeof(mask));

    if (ioctl(sock, SIOCGIFADDR, &addr, sizeof(addr)) == 0 &&

      ioctl(sock, SIOCGIFNETMASK, &mask, sizeof(mask)) == 0)

      run_ifaddr_callback(callback, cb_data,

                &addr.ifr_addr, &mask.ifr_addr);

    ifr = (struct ifreq *) ((char *) ifr + _SIZEOF_ADDR_IFREQ(*ifr));

  }

  free(buffer);

  close(sock);

  return 0;

}

#else             /* !defined(SIOCGIFCONF) */

/*

 * Enumerate the system's network interface addresses and call the callback

 * for each one.  Returns 0 if successful, -1 if trouble.

 *

 * This version is our fallback if there's no known way to get the

 * interface addresses.  Just return the standard loopback addresses.

 */

int

pg_foreach_ifaddr(PgIfAddrCallback callback, void *cb_data)

{

  struct sockaddr_in addr;

  struct sockaddr_storage mask;

  struct sockaddr_in6 addr6;

  /* addr 127.0.0.1/8 */

  memset(&addr, 0, sizeof(addr));

  addr.sin_family = AF_INET;

  addr.sin_addr.s_addr = pg_ntoh32(0x7f000001);

  memset(&mask, 0, sizeof(mask));

  pg_sockaddr_cidr_mask(&mask, "8", AF_INET);

  run_ifaddr_callback(callback, cb_data,

            (struct sockaddr *) &addr,

            (struct sockaddr *) &mask);

  /* addr ::1/128 */

  memset(&addr6, 0, sizeof(addr6));

  addr6.sin6_family = AF_INET6;

  addr6.sin6_addr.s6_addr[15] = 1;

  memset(&mask, 0, sizeof(mask));

  pg_sockaddr_cidr_mask(&mask, "128", AF_INET6);

  run_ifaddr_callback(callback, cb_data,

            (struct sockaddr *) &addr6,

            (struct sockaddr *) &mask);

  return 0;

}

#endif              /* !defined(SIOCGIFCONF) */

#endif              /* !HAVE_GETIFADDRS */