bgp_filter.c

大名鼎鼎的路由器源码。程序分ZEBRA、OSPFRIP等3个包。程序框架采用一个路由协议一个进程的方式

  if (as_list_empty (aslist))
    as_list_delete (aslist);

  /* Run hook function. */
  if (as_list_master.delete_hook)
    (*as_list_master.delete_hook) ();
}

static int
as_filter_match (struct as_filter *asfilter, struct aspath *aspath)
{
  if (bgp_regexec (asfilter->reg, aspath) != REG_NOMATCH)
    return 1;
  return 0;
}

/* Apply AS path filter to AS. */
enum as_filter_type
as_list_apply (struct as_list *aslist, void *object)
{
  struct as_filter *asfilter;
  struct aspath *aspath;

  aspath = (struct aspath *) object;

  if (aslist == NULL)
    return AS_FILTER_DENY;

  for (asfilter = aslist->head; asfilter; asfilter = asfilter->next)
    {
      if (as_filter_match (asfilter, aspath))
	return asfilter->type;
    }
  return AS_FILTER_DENY;
}

/* Add hook function. */
void
as_list_add_hook (void (*func) ())
{
  as_list_master.add_hook = func;
}

/* Delete hook function. */
void
as_list_delete_hook (void (*func) ())
{
  as_list_master.delete_hook = func;
}

int
as_list_dup_check (struct as_list *aslist, struct as_filter *new)
{
  struct as_filter *asfilter;

  for (asfilter = aslist->head; asfilter; asfilter = asfilter->next)
    {
      if (asfilter->type == new->type
	  && strcmp (asfilter->reg_str, new->reg_str) == 0)
	return 1;
    }
  return 0;
}

DEFUN (ip_as_path, ip_as_path_cmd,
       "ip as-path access-list WORD (deny|permit) .LINE",
       IP_STR
       "BGP autonomous system path filter\n"
       "Specify an access list name\n"
       "Regular expression access list name\n"
       "Specify packets to reject\n"
       "Specify packets to forward\n"
       "A regular-expression to match the BGP AS paths\n")
{
  enum as_filter_type type;
  struct as_filter *asfilter;
  struct as_list *aslist;
  regex_t *regex;
  struct buffer *b;
  int i;
  char *regstr;
  int first = 0;

  /* Check the filter type. */
  if (strncmp (argv[1], "p", 1) == 0)
    type = AS_FILTER_PERMIT;
  else if (strncmp (argv[1], "d", 1) == 0)
    type = AS_FILTER_DENY;
  else
    {
      vty_out (vty, "filter type must be [permit|deny]%s", VTY_NEWLINE);
      return CMD_WARNING;
    }

  /* Check AS path regex. */
  b = buffer_new (1024);
  for (i = 2; i < argc; i++)
    {
      if (first)
	buffer_putc (b, ' ');
      else
	first = 1;

      buffer_putstr (b, argv[i]);
    }
  buffer_putc (b, '\0');

  regstr = buffer_getstr (b);
  buffer_free (b);

  regex = bgp_regcomp (regstr);
  if (!regex)
    {
      free (regstr);
      vty_out (vty, "can't compile regexp %s%s", argv[0],
	       VTY_NEWLINE);
      return CMD_WARNING;
    }

  asfilter = as_filter_make (regex, regstr, type);
  
  free (regstr);

  /* Install new filter to the access_list. */
  aslist = as_list_get (argv[0]);

  /* Duplicate insertion check. */;
  if (as_list_dup_check (aslist, asfilter))
    as_filter_free (asfilter);
  else
    as_list_filter_add (aslist, asfilter);

  return CMD_SUCCESS;
}

DEFUN (no_ip_as_path,
       no_ip_as_path_cmd,
       "no ip as-path access-list WORD (deny|permit) .LINE",
       NO_STR
       IP_STR
       "BGP autonomous system path filter\n"
       "Specify an access list name\n"
       "Regular expression access list name\n"
       "Specify packets to reject\n"
       "Specify packets to forward\n"
       "A regular-expression to match the BGP AS paths\n")
{
  enum as_filter_type type;
  struct as_filter *asfilter;
  struct as_list *aslist;
  struct buffer *b;
  int i;
  int first = 0;
  char *regstr;
  regex_t *regex;

  /* Lookup AS list from AS path list. */
  aslist = as_list_lookup (argv[0]);
  if (aslist == NULL)
    {
      vty_out (vty, "ip as-path access-list %s doesn't exist%s", argv[0],
	       VTY_NEWLINE);
      return CMD_WARNING;
    }

  /* Check the filter type. */
  if (strncmp (argv[1], "p", 1) == 0)
    type = AS_FILTER_PERMIT;
  else if (strncmp (argv[1], "d", 1) == 0)
    type = AS_FILTER_DENY;
  else
    {
      vty_out (vty, "filter type must be [permit|deny]%s", VTY_NEWLINE);
      return CMD_WARNING;
    }
  
  /* Compile AS path. */
  b = buffer_new (1024);
  for (i = 2; i < argc; i++)
    {
      if (first)
	buffer_putc (b, ' ');
      else
	first = 1;

      buffer_putstr (b, argv[i]);
    }
  buffer_putc (b, '\0');

  regstr = buffer_getstr (b);
  buffer_free (b);

  regex = bgp_regcomp (regstr);
  if (!regex)
    {
      free (regstr);
      vty_out (vty, "can't compile regexp %s%s", argv[0],
	       VTY_NEWLINE);
      return CMD_WARNING;
    }

  /* Lookup asfilter. */
  asfilter = as_filter_lookup (aslist, regstr, type);

  free (regstr);
  bgp_regex_free (regex);

  if (asfilter == NULL)
    {
      vty_out (vty, "%s", VTY_NEWLINE);
      return CMD_WARNING;
    }

  as_list_filter_delete (aslist, asfilter);

  return CMD_SUCCESS;
}

DEFUN (no_ip_as_path_all,
       no_ip_as_path_all_cmd,
       "no ip as-path access-list WORD",
       NO_STR
       IP_STR
       "BGP autonomous system path filter\n"
       "Specify an access list name\n"
       "Regular expression access list name\n")
{
  struct as_list *aslist;

  aslist = as_list_lookup (argv[0]);
  if (aslist == NULL)
    {
      vty_out (vty, "ip as-path access-list %s doesn't exist%s", argv[0],
	       VTY_NEWLINE);
      return CMD_WARNING;
    }

  as_list_delete (aslist);

  /* Run hook function. */
  if (as_list_master.delete_hook)
    (*as_list_master.delete_hook) ();

  return CMD_SUCCESS;
}

void
as_list_show (struct vty *vty, struct as_list *aslist)
{
  struct as_filter *asfilter;

  vty_out (vty, "AS path access list %s%s", aslist->name, VTY_NEWLINE);

  for (asfilter = aslist->head; asfilter; asfilter = asfilter->next)
    {
      vty_out (vty, "    %s %s%s", filter_type_str (asfilter->type),
	       asfilter->reg_str, VTY_NEWLINE);
    }
}

void
as_list_show_all (struct vty *vty)
{
  struct as_list *aslist;
  struct as_filter *asfilter;

  for (aslist = as_list_master.num.head; aslist; aslist = aslist->next)
    {
      vty_out (vty, "AS path access list %s%s", aslist->name, VTY_NEWLINE);

      for (asfilter = aslist->head; asfilter; asfilter = asfilter->next)
	{
	  vty_out (vty, "    %s %s%s", filter_type_str (asfilter->type),
		   asfilter->reg_str, VTY_NEWLINE);
	}
    }

  for (aslist = as_list_master.str.head; aslist; aslist = aslist->next)
    {
      vty_out (vty, "AS path access list %s%s", aslist->name, VTY_NEWLINE);

      for (asfilter = aslist->head; asfilter; asfilter = asfilter->next)
	{
	  vty_out (vty, "    %s %s%s", filter_type_str (asfilter->type),
		   asfilter->reg_str, VTY_NEWLINE);
	}
    }
}

DEFUN (show_ip_as_path_access_list,
       show_ip_as_path_access_list_cmd,
       "show ip as-path-access-list WORD",
       SHOW_STR
       IP_STR
       "List AS path access lists\n"
       "AS path access list name\n")
{
  struct as_list *aslist;

  aslist = as_list_lookup (argv[0]);
  if (aslist)
    as_list_show (vty, aslist);

  return CMD_SUCCESS;
}

DEFUN (show_ip_as_path_access_list_all,
       show_ip_as_path_access_list_all_cmd,
       "show ip as-path-access-list",
       SHOW_STR
       IP_STR
       "List AS path access lists\n")
{
  as_list_show_all (vty);
  return CMD_SUCCESS;
}

int
config_write_as_list (struct vty *vty)
{
  struct as_list *aslist;
  struct as_filter *asfilter;
  int write = 0;

  for (aslist = as_list_master.num.head; aslist; aslist = aslist->next)
    for (asfilter = aslist->head; asfilter; asfilter = asfilter->next)
      {
	vty_out (vty, "ip as-path access-list %s %s %s%s",
		 aslist->name, filter_type_str (asfilter->type), 
		 asfilter->reg_str,
		 VTY_NEWLINE);
	write++;
      }

  for (aslist = as_list_master.str.head; aslist; aslist = aslist->next)
    for (asfilter = aslist->head; asfilter; asfilter = asfilter->next)
      {
	vty_out (vty, "ip as-path access-list %s %s %s%s",
		 aslist->name, filter_type_str (asfilter->type), 
		 asfilter->reg_str,
		 VTY_NEWLINE);
	write++;
      }
  return write;
}

struct cmd_node as_list_node =
{
  AS_LIST_NODE,
  "",
  1
};

/* Register functions. */
void
bgp_filter_init ()
{
  install_node (&as_list_node, config_write_as_list);

  install_element (CONFIG_NODE, &ip_as_path_cmd);
  install_element (CONFIG_NODE, &no_ip_as_path_cmd);
  install_element (CONFIG_NODE, &no_ip_as_path_all_cmd);

  install_element (VIEW_NODE, &show_ip_as_path_access_list_cmd);
  install_element (VIEW_NODE, &show_ip_as_path_access_list_all_cmd);
  install_element (ENABLE_NODE, &show_ip_as_path_access_list_cmd);
  install_element (ENABLE_NODE, &show_ip_as_path_access_list_all_cmd);
}