/***************************************************************************
 * netutils.c -- This contains some useful little network/socket related   *
 * utility functions.                                                      *
 *                                                                         *
 ***********************IMPORTANT NSOCK LICENSE TERMS***********************
 *
 * The nsock parallel socket event library is (C) 1999-2024 Nmap Software LLC
 * This library is free software; you may redistribute and/or modify it under
 * the terms of the GNU General Public License as published by the Free Software
 * Foundation; Version 2. This guarantees your right to use, modify, and
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 *
 * As a special exception to the GPL terms, Nmap Software LLC grants permission
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 ***************************************************************************/

/* $Id: netutils.c 38790 2024-02-28 18:46:45Z dmiller $ */

#include "netutils.h"
#include "error.h"

#if WIN32
#include "Winsock2.h"
#endif

#if HAVE_SYS_TIME_H
#include <sys/time.h>
#endif
#if HAVE_SYS_RESOURCE_H
#include <sys/resource.h>
#endif
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#if HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#if HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#if HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#if HAVE_FCNTL_H
#include <fcntl.h>
#endif
#if HAVE_SYS_UN_H
#include <sys/un.h>
#endif

static int netutils_debugging = 0;

/* maximize the number of file descriptors (including sockets) allowed for this
 * process and return that maximum value (note -- you better not actually open
 * this many -- stdin, stdout, other files opened by libraries you use, etc. all
 * count toward this limit.  Leave a little slack */
rlim_t maximize_fdlimit(void) {

#ifndef WIN32
  struct rlimit r;
  static int maxfds_set = 0;
  static rlim_t maxfds = 0;

  if (maxfds_set)
    return maxfds;

#ifndef RLIMIT_NOFILE
 #ifdef RLIMIT_OFILE
  #define RLIMIT_NOFILE RLIMIT_OFILE
 #else
  #error Neither RLIMIT_NOFILE nor RLIMIT_OFILE defined
 #endif
#endif
  if (!getrlimit(RLIMIT_NOFILE, &r)) {
    maxfds = r.rlim_cur;
    r.rlim_cur = r.rlim_max;
    if (!setrlimit(RLIMIT_NOFILE, &r))
      if (netutils_debugging)
        perror("setrlimit RLIMIT_NOFILE failed");

    if (!getrlimit(RLIMIT_NOFILE, &r)) {
      maxfds = r.rlim_cur;
    }
    maxfds_set = 1;
    return maxfds;
  }
#endif /* !WIN32 */
  return 0;
}

#if HAVE_SYS_UN_H
  #define PEER_STR_LEN sizeof(((struct sockaddr_un *) 0)->sun_path)
#else
  #define PEER_STR_LEN sizeof("[ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255]:xxxxx")
#endif

#if HAVE_SYS_UN_H
/* Get the UNIX domain socket path or empty string if the address family != AF_UNIX. */
const char *get_unixsock_path(const struct sockaddr_storage *addr) {
  struct sockaddr_un *su = (struct sockaddr_un *)addr;

  if (!addr || addr->ss_family != AF_UNIX)
    return "";

  return (const char *)su->sun_path;
}
#endif

static int get_port(const struct sockaddr_storage *ss) {
  if (ss->ss_family == AF_INET)
    return ntohs(((struct sockaddr_in *) ss)->sin_port);
#if HAVE_IPV6
  else if (ss->ss_family == AF_INET6)
    return ntohs(((struct sockaddr_in6 *) ss)->sin6_port);
#endif

  return -1;
}

static char *get_addr_string(const struct sockaddr_storage *ss, size_t sslen) {
  static char buffer[PEER_STR_LEN];

#if HAVE_SYS_UN_H
  if (ss->ss_family == AF_UNIX) {
    sprintf(buffer, "%s", get_unixsock_path(ss));
    return buffer;
  }
#endif

  sprintf(buffer, "%s:%d", inet_ntop_ez(ss, sslen), get_port(ss));
  return buffer;
}

/* Get the peer/host address string.
 * In case we have support for UNIX domain sockets, function returns
 * string containing path to UNIX socket if the address family is AF_UNIX,
 * otherwise it returns string containing "<address>:<port>". */
char *get_peeraddr_string(const struct niod *iod) {
  if (iod->peerlen > 0)
    return get_addr_string(&iod->peer, iod->peerlen);
  else
    return "peer unspecified";
}

/* Get the local bind address string. */
char *get_localaddr_string(const struct niod *iod) {
  return get_addr_string(&iod->local, iod->locallen);
}
