/* options.c -- process the command line options
  Copyright (C) 2001-2025 Free Software Foundation, Inc.

  This file is part of GNU Inetutils.

  GNU Inetutils is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or (at
  your option) any later version.

  GNU Inetutils is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program.  If not, see `http://www.gnu.org/licenses/'. */

/* Written by Marcus Brinkmann.  */

#include <config.h>

#include <stdio.h>
#include <errno.h>

#if STDC_HEADERS
# include <stdlib.h>
#else
# ifndef HAVE_STRCHR
#  define strchr index
#  define strrchr rindex
# endif
#endif

#include <string.h>

#include <sys/socket.h>
#include <net/if.h>

#include <attribute.h>

#include "ifconfig.h"

/* List available interfaces.  */
int list_mode;

/* Be verbose about actions.  */
int verbose;

/* Flags asked for, possibly still pending application.  */
static int pending_setflags = 0;
static int pending_clrflags = 0;
static int pending_valid = 0;

/* Array of all interfaces on the command line.  */
struct ifconfig *ifs;

/* Size of IFS.  */
int nifs;

static struct ifconfig ifconfig_initializer = {
  NULL,				/* name */
  0,				/* valid */
  NULL, NULL, 0, NULL, NULL, NULL, NULL, 0, 0, 0, 0, NULL
};

struct format formats[] = {
  /* This is the default output format if no system_default_format is
     specified.  */
  {"default",
   "Default format.  Equivalent to \"gnu\".",
   "${format}{gnu}"},
  /* This is the standard GNU output.  */
  {"gnu",
   "Standard GNU output format.",
   "${ifdisplay?}{${first?}{}{${\\n}}${format}{gnu-one-entry}}"},
  {"gnu-one-entry",
   "Same as GNU, but without additional newlines between the entries.",
   "${format}{check-existence}"
   "${ifdisplay?}{"
   "${name} (${index}):${\\n}"
   "${addr?}{  inet address ${tab}{16}${addr}${\\n}}"
   "${netmask?}{  netmask ${tab}{16}${netmask}${\\n}}"
   "${brdaddr?}{  broadcast ${tab}{16}${brdaddr}${\\n}}"
   "${dstaddr?}{  peer address ${tab}{16}${dstaddr}${\\n}}"
   "${exists?}{tunnel?}{"
   "${tunnel?}{  tunnel src ${tab}{16}${tunsrc}${\\n}}}"
   "${exists?}{tunnel?}{"
   "${tunnel?}{  tunnel dst ${tab}{16}${tundst}${\\n}}}"
   "${flags?}{  flags ${tab}{16}${flags}${\\n}}"
   "${mtu?}{  mtu ${tab}{16}${mtu}${\\n}}"
   "${metric?}{  metric ${tab}{16}${metric}${\\n}}"
   "${exists?}{hwtype?}{${hwtype?}{  link encap ${tab}{16}${hwtype}${\\n}}}"
   "${exists?}{hwaddr?}{${hwaddr?}{  hardware addr ${tab}{16}${hwaddr}${\\n}}}"
   "${media?}{  link medium ${tab}{16}${media}${\\n}}"
   "${status?}{  link status ${tab}{16}${status}${\\n}}"
   "${exists?}{txqlen?}{${txqlen?}{  tx queue len ${tab}{16}${txqlen}${\\n}}}"
   "}"},
  /* Resembles the output of ifconfig 1.39 (1999-03-19) in net-tools 1.52.  */
  {"net-tools",
   "Similar to the output of net-tools.  Default for GNU/Linux.",
   "${format}{check-existence}"
   "${ifdisplay?}{"
   "${name}${exists?}{hwtype?}{${hwtype?}{${tab}{10}Link encap:${hwtype}}"
   "${hwaddr?}{  HWaddr ${hwaddr}}}${\\n}"
   "${addr?}{${tab}{10}inet addr:${addr}"
   "${dstaddr?}{  P-t-P:${dstaddr}}"
   "${brdaddr?}{  Bcast:${brdaddr}}"
   "${netmask?}{  Mask:${netmask}}"
   "${newline}}"
   "${tab}{10}${flags}"
   "${mtu?}{  MTU:${mtu}}"
   "${metric?}{  Metric:${metric}}"
   "${media?}{"
   "${newline}${tab}{10}Media: ${media}"
   "${status?}{, ${status}}}"
   "${exists?}{ifstat?}{"
   "${ifstat?}{"
   "${newline}          RX packets:${rxpackets}"
   " errors:${rxerrors} dropped:${rxdropped} overruns:${rxfifoerr}"
   " frame:${rxframeerr}"
   "${newline}          TX packets:${txpackets}"
   " errors:${txerrors} dropped:${txdropped} overruns:${txfifoerr}"
   " carrier:${txcarrier}"
   "${newline}"
   "          collisions:${collisions}"
   "${exists?}{txqlen?}{${txqlen?}{ txqueuelen:${txqlen}}}"
   "${newline}"
   "          RX bytes:${rxbytes}  TX bytes:${txbytes}"
   "}}{"
   "${exists?}{txqlen?}{${txqlen?}{ ${tab}{10}txqueuelen:${txqlen}}${\\n}}}"
   "${newline}"
   "${exists?}{map?}{${map?}{${irq?}{"
   "          Interrupt:${irq}"
   "${baseaddr?}{ Base address:0x${baseaddr}{%x}}"
   "${memstart?}{ Memory:${memstart}{%lx}-${memend}{%lx}}"
   "${dma?}{ DMA chan:${dma}{%x}}" "${newline}" "}}}" "${newline}" "}"},
  {"netstat",
   "Terse output, similar to that of \"netstat -i\".",
   "${first?}{Iface    MTU Met    RX-OK RX-ERR RX-DRP RX-OVR    TX-OK TX-ERR TX-DRP TX-OVR Flg${newline}}"
   "${format}{check-existence}" "${name}${tab}{6}${mtu}{%6d} ${metric}{%3d}"
   /* Insert blanks without ifstat.  */
   "${exists?}{ifstat?}{"
   "${ifstat?}{"
   " ${rxpackets}{%8lu} ${rxerrors}{%6lu} ${rxdropped}{%6lu} ${rxfifoerr}{%6lu}"
   " ${txpackets}{%8lu} ${txerrors}{%6lu} ${txdropped}{%6lu} ${txfifoerr}{%6lu}"
   "}{   - no statistics available -}}"
   "${tab}{76} ${flags?}{${flags}{short}}{[NO FLAGS]}" "${newline}"},
  /* Resembles the output of ifconfig shipped with unix systems like
     Solaris 2.7 or HPUX 10.20.  */
  {"unix",
   "Traditional UNIX interface listing.  Default for Solaris, BSD and HPUX.",
   "${format}{check-existence}"
   "${ifdisplay?}{"
   "${name}: flags=${flags}{number}{%x}<${flags}{string}{,}>"
   "${metric?}{ metric ${metric}}" "${mtu?}{ mtu ${mtu}}${\\n}"
   /* Print only if hwtype emits something.  */
   "${exists?}{hwtype?}{"
   "${hwtype?}{${\\t}${hwtype}${exists?}{hwaddr?}{"
   "${hwaddr?}{ ${hwaddr}}}${\\n}}}"
   "${exists?}{tunnel?}{"
   "${tunnel?}{${\\t}tunnel inet ${tunsrc} --> ${tundst}${\\n}}}"
   "${addr?}{${\\t}inet ${addr}"
   "${dstaddr?}{ --> ${dstaddr}}"
   " netmask ${netmask}{0}{%#02x}${netmask}{1}{%02x}"
   "${netmask}{2}{%02x}${netmask}{3}{%02x}"
   "${brdaddr?}{ broadcast ${brdaddr}}${\\n}}"
   "${media?}{${\\t}media: ${media}${\\n}}"
   "${status?}{${\\t}status: ${status}${\\n}}" "}"},
  /* Resembles the output of ifconfig shipped with OSF 4.0g.  */
  {"osf",
   "OSF-style output.",
   "${format}{check-existence}"
   "${ifdisplay?}{"
   "${name}: flags=${flags}{number}{%x}<${flags}{string}{,}>${\\n}"
   "${exists?}{tunnel?}{"
   "${tunnel?}{${\\t}inet tunnel src ${tunsrc} tunnel dst ${tundst}${\\n}}}"
   "${addr?}{${\\t}inet ${addr}"
   "${dstaddr?}{ --> ${dstaddr}}"
   " netmask ${netmask}{0}{%02x}${netmask}{1}{%02x}"
   "${netmask}{2}{%02x}${netmask}{3}{%02x}"
   "${brdaddr?}{ broadcast ${brdaddr}}" "${mtu?}{ ipmtu ${mtu}}${\\n}}"
   "${exists?}{hwtype?}{"
   "${hwtype?}{${\\t}${hwtype}${exists?}{hwaddr?}{"
   "${hwaddr?}{ ${hwaddr}}}${\\n}}}" "}"},
  {"check",
   "Shorthand for `check-existence'.",
   "${format}{check-existence}"},
  /* If interface does not exist, print error message and exit. */
  {"check-existence",
   "If interface does not exist, print error message and exit.",
   "${index?}{}"
   "{${error}{${progname}: error: interface `${name}' does not exist${\\n}}"
   "${exit}{1}}"},
  {"?",
   "Synonym for `help'.",
   "${format}{help}"},
  {"help",
   "Display this help output.",
   "${foreachformat}{"
   "${name}:${tab}{17}${docstr}"
   "${verbose?}{"
   "${newline}"
   "${rep}{79}{-}"
   "${newline}" "${defn}" "${newline}" "}" "${newline}" "}" "${exit}{0}"},
  {NULL, NULL, NULL}
};

/* Default format.  */
const char *default_format;
/* Display all interfaces, even if down */
int all_option;
/* True if interfaces were given in the command line */
int ifs_cmdline;

enum
{
  METRIC_OPTION = 256,
  FORMAT_OPTION,
  UP_OPTION,
  DOWN_OPTION,
};

static struct argp_option argp_options[] = {
#define GRP 10
  {"verbose", 'v', NULL, 0,
   "output information when configuring interface", GRP},
  {"all", 'a', NULL, 0,
   "display all available interfaces", GRP},
  {"interface", 'i', "NAME", 0,
   "configure network interface NAME", GRP},
  {"address", 'A', "ADDR", 0,
   "set interface address to ADDR", GRP},
  {"netmask", 'm', "MASK", 0,
   "set netmask to MASK", GRP},
  {"dstaddr", 'd', "ADDR", 0,
   "set destination (peer) address to ADDR", GRP},
  {"peer", 'p', "ADDR", OPTION_ALIAS,
   "synonym for dstaddr", GRP},
  {"broadcast", 'B', "ADDR", 0,
   "set broadcast address to ADDR", GRP},
  {"brdaddr", 'b', NULL, OPTION_ALIAS,
   "synonym for broadcast", GRP},	/* FIXME: Do we really need it? */
  {"mtu", 'M', "N", 0,
   "set mtu of interface to N", GRP},
  {"metric", METRIC_OPTION, "N", 0,
   "set metric of interface to N", GRP},
  {"format", FORMAT_OPTION, "FORMAT", 0,
   "select output format; set to `help' for info", GRP},
  {"up", UP_OPTION, NULL, 0,
   "activate the interface", GRP},
  {"down", DOWN_OPTION, NULL, 0,
   "shut the interface down", GRP},
  {"flags", 'F', "FLAG[,FLAG...]", 0,
   "set interface flags", GRP},
  {"list", 'l', NULL, 0,
   "list available or selected interfaces", GRP},
  {"short", 's', NULL, 0,
   "short output format", GRP},
#undef GRP
  {NULL, 0, NULL, 0, NULL, 0}
};

const char doc[] = "Configure network interfaces.";
const char *program_authors[] = {
  "Marcus Brinkmann",
  NULL
};

struct format *
format_find (const char *name)
{
  struct format *frm;

  for (frm = formats; frm->name; frm++)
    {
      if (strcmp (frm->name, name) == 0)
	return frm;
    }
  return NULL;
}

struct ifconfig *
parse_opt_new_ifs (char *name)
{
  struct ifconfig *ifp;

  ifs_cmdline = 1;
  ifs = realloc (ifs, ++nifs * sizeof (struct ifconfig));
  if (!ifs)
    error (EXIT_FAILURE, errno,
	   "can't get memory for interface configuration");
  ifp = &ifs[nifs - 1];
  *ifp = ifconfig_initializer;
  ifp->name = name;
  return ifp;
}

#define PARSE_OPT_SET_ADDR(field, fname, fvalid) \
void								\
parse_opt_set_##field (struct ifconfig *ifp, char *addr)	\
{								\
  if (!ifp)							\
    error (EXIT_FAILURE, 0,                                     \
	   "no interface specified for %s `%s'", #fname, addr); \
  if (ifp->valid & IF_VALID_##fvalid)				\
    error (EXIT_FAILURE, 0,                                     \
	   "only one %s allowed for interface `%s'",		\
	   #fname, ifp->name);				        \
  ifp->field = addr;						\
  ifp->valid |= IF_VALID_##fvalid;				\
}

PARSE_OPT_SET_ADDR (address, address, ADDR)
PARSE_OPT_SET_ADDR (netmask, netmask, NETMASK)
PARSE_OPT_SET_ADDR (dstaddr, destination / peer address, DSTADDR)
PARSE_OPT_SET_ADDR (brdaddr, broadcast address, BRDADDR)
PARSE_OPT_SET_ADDR (hwaddr, hardware address, HWADDR)
#define PARSE_OPT_SET_INT(field, fname, fvalid) \
void								\
parse_opt_set_##field (struct ifconfig *ifp, char *arg)		\
{								\
  char *end;							\
  if (!ifp)							\
    error (EXIT_FAILURE, 0,                                     \
	   "no interface specified for %s `%s'\n",              \
	   #fname, arg);                                        \
  if (ifp->valid & IF_VALID_##fvalid)				\
    error (EXIT_FAILURE, 0,                                     \
	   "only one %s allowed for interface `%s'",		\
	   #fname, ifp->name);				        \
  ifp->field =  strtol (arg, &end, 0);				\
  if (*arg == '\0' || *end != '\0')				\
    error (EXIT_FAILURE, 0,                                     \
	   "mtu value `%s' for interface `%s' is not a number",	\
	   arg, ifp->name);			                \
  ifp->valid |= IF_VALID_##fvalid;				\
}
  PARSE_OPT_SET_INT (mtu, mtu value, MTU)
PARSE_OPT_SET_INT (metric, metric value, METRIC)
     void parse_opt_set_af (struct ifconfig *ifp, char *af)
{
  if (!ifp)
    error (EXIT_FAILURE, 0,
	   "no interface specified for address family `%s'", af);

  if (!strcasecmp (af, "inet"))
    ifp->af = AF_INET;
  else
    error (EXIT_FAILURE, 0,
	   "unknown address family `%s' for interface `%s': is not a number",
	   af, ifp->name);
  ifp->valid |= IF_VALID_AF;
}

void
parse_opt_set_flag (struct ifconfig *ifp MAYBE_UNUSED, int flag, int rev)
{
  if (ifp)
    ifp->valid |= IF_VALID_FLAGS;
  else
    pending_valid |= IF_VALID_FLAGS;

  if (rev)
    {
      pending_clrflags |= flag;
      pending_setflags &= ~flag;
    }
  else
    {
      pending_setflags |= flag;
      pending_clrflags &= ~flag;
    }
}

void
parse_opt_flag_list (struct ifconfig *ifp, const char *name)
{
  while (*name)
    {
      int mask, rev;
      char *p = strchr (name, ',');
      size_t len;

      if (p)
	len = p - name;
      else
	len = strlen (name);

      if ((mask = if_nametoflag (name, len, &rev)) == 0)
	error (EXIT_FAILURE, 0, "unknown flag %*.*s",
	       (int) len, (int) len, name);
      parse_opt_set_flag (ifp, mask, rev);

      name += len;
      if (p)
	name++;
    }
}

void
parse_opt_set_point_to_point (struct ifconfig *ifp, char *addr)
{
  parse_opt_set_dstaddr (ifp, addr);
  parse_opt_set_flag (ifp, IFF_POINTOPOINT, 0);
}

void
parse_opt_set_default_format (const char *format)
{
  struct format *frm;

  if (!format)
    format = system_default_format ? system_default_format : "default";

  for (frm = formats; frm->name; frm++)
    if (!strcmp (format, frm->name))
      break;
  if (frm == NULL || frm->templ == NULL)
    error (EXIT_FAILURE, 0, "%s: unknown output format", format);
  default_format = frm->templ;
}

static int
is_comment_line (const char *p, size_t len)
{
  while (len--)
    {
      int c = *p++;
      switch (c)
	{
	case ' ':
	case '\t':
	  continue;

	case '#':
	  return 1;

	default:
	  return 0;
	}
    }
  return 0;
}

void
parse_opt_set_default_format_from_file (const char *file)
{
  static struct obstack stk;
  FILE *fp;
  char *buf = NULL;
  size_t size = 0;

  fp = fopen (file, "r");
  if (!fp)
    error (EXIT_FAILURE, errno, "cannot open format file %s", file);

  obstack_init (&stk);
  while (getline (&buf, &size, fp) > 0)
    {
      size_t len = strlen (buf);

      if (len >= 1 && buf[len - 1] == '\n')
	len--;

      if (len == 0 || is_comment_line (buf, len))
	continue;
      obstack_grow (&stk, buf, len);
    }
  free (buf);
  fclose (fp);
  obstack_1grow (&stk, 0);
  default_format = obstack_finish (&stk);
}

/* Must be reentrant!  */
void
parse_opt_finalize (struct ifconfig *ifp)
{
  /* The flags `--up' and `--down' are allowed early.  */
  if (ifp && pending_valid)
    {
      ifp->valid |= pending_valid;
      pending_valid = 0;
    }

  /* Only the empty set of actions, i.e., only the interface name
   * is present on the command line, merits printout of status.
   */
  if (ifp && !ifp->valid)
    {
      ifp->valid = IF_VALID_FORMAT;
      ifp->format = default_format;
    }

  if (ifp && (pending_setflags | pending_clrflags))
    {
      ifp->setflags |= pending_setflags;
      ifp->clrflags |= pending_clrflags;
      pending_setflags = pending_clrflags = 0;
    }
}

static error_t
parse_opt (int key, char *arg, struct argp_state *state)
{
  struct ifconfig *ifp = *(struct ifconfig **) state->input;

  switch (key)
    {
    case ARGP_KEY_INIT:
      state->child_inputs[0] = state->input;
      break;

    case 'i':			/* Interface name.  */
      parse_opt_finalize (ifp);
      ifp = parse_opt_new_ifs (arg);
      *(struct ifconfig **) state->input = ifp;
      break;

    case 'a':
      all_option = 1;
      break;

    case 'A':			/* Interface address.  */
      {
	char *netlen = strchr (arg, '/');

	if (netlen)
	  {
	    char *end, *str;
	    unsigned n;
	    struct in_addr addr;

	    *netlen++ = 0;

	    n = strtol (netlen, &end, 10);
	    if (!(*netlen && !*end) || n < 0 || n > 32)
	      error (EXIT_FAILURE, 0, "Wrong netmask length %s", netlen);

	    addr.s_addr =
	      n ? htonl (INADDR_BROADCAST << (32 - n)) : INADDR_ANY;
	    str = strdup (inet_ntoa (addr));
	    parse_opt_set_netmask (ifp, str);
	  }

	parse_opt_set_address (ifp, arg);
	break;
      }

    case 'm':			/* Interface netmask.  */
      parse_opt_set_netmask (ifp, arg);
      break;

    case 'd':			/* Interface dstaddr.  */
    case 'p':
      parse_opt_set_point_to_point (ifp, arg);
      break;

    case 'b':			/* Interface broadcast address.  */
    case 'B':
      parse_opt_set_brdaddr (ifp, arg);
      break;

    case 'F':
      parse_opt_flag_list (ifp, arg);
      break;

    case 'M':			/* Interface MTU.  */
      parse_opt_set_mtu (ifp, arg);
      break;

    case 's':
      parse_opt_set_default_format ("netstat");
      break;

    case 'l':
      list_mode++;
      break;

    case 'v':
      verbose++;
      break;

    case METRIC_OPTION:	/* Interface metric.  */
      parse_opt_set_metric (ifp, arg);
      break;

    case FORMAT_OPTION:	/* Output format.  */
      if (arg && arg[0] == '@')
	parse_opt_set_default_format_from_file (arg + 1);
      else
	parse_opt_set_default_format (arg);
      break;

    case UP_OPTION:
      parse_opt_set_flag (ifp, IFF_UP | IFF_RUNNING, 0);
      break;

    case DOWN_OPTION:
      parse_opt_set_flag (ifp, IFF_UP, 1);
      break;

    default:
      return ARGP_ERR_UNKNOWN;
    }

  return 0;
}

static char *
default_help_filter (int key, const char *text, void *input MAYBE_UNUSED)
{
  char *s;

  switch (key)
    {
    default:
      s = (char *) text;
      break;

    case ARGP_KEY_HELP_EXTRA:
      s = if_list_flags ("Known flags are: ");
    }
  return s;
}

static struct argp_child argp_children[2];
static struct argp argp = {
  argp_options,
  parse_opt,
  NULL,
  doc,
  NULL,
  default_help_filter,
  NULL
};

static int
cmp_if_name (const void *a, const void *b)
{
  const struct ifconfig *ifa = a;
  const struct ifconfig *ifb = b;

  return strcmp (ifa->name, ifb->name);
}

void
parse_cmdline (int argc, char *argv[])
{
  int index;
  struct ifconfig *ifp = ifs;

  parse_opt_set_default_format (NULL);
  iu_argp_init ("ifconfig", program_authors);
  argp_children[0] = system_argp_child;
  argp.children = argp_children;
  argp.args_doc = system_help;
  argp_parse (&argp, argc, argv, ARGP_IN_ORDER, &index, &ifp);

  parse_opt_finalize (ifp);

  if (index < argc)
    {
      if (!system_parse_opt_rest (&ifp, argc - index, &argv[index]))
	error (EXIT_FAILURE, 0, "invalid arguments");
      parse_opt_finalize (ifp);
    }
  if (!ifs)
    {
      /* No interfaces specified.  Get a list of all interfaces.  */
      struct if_nameindex *ifnx, *ifnxp;

      ifnx = ifnxp = system_if_nameindex ();
      if (!ifnx)
	error (EXIT_FAILURE, 0, "could not get list of interfaces");
      while (ifnxp->if_index != 0 || ifnxp->if_name != NULL)
	{
	  struct ifconfig *ifp;

	  ifs = realloc (ifs, ++nifs * sizeof (struct ifconfig));
	  if (!ifs)
	    error (EXIT_FAILURE, errno,
		   "can't get memory for interface configuration");
	  ifp = &ifs[nifs - 1];
	  *ifp = ifconfig_initializer;
	  ifp->name = strdup (ifnxp->if_name);
	  if (!ifs)
	    error (EXIT_FAILURE, errno,
		   "can't get memory for interface configuration name");
	  ifp->valid = IF_VALID_FORMAT;
	  ifp->format = default_format;
	  ifnxp++;
	}
      if_freenameindex (ifnx);
      qsort (ifs, nifs, sizeof (ifs[0]), cmp_if_name);
    }
}