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

/* AS path filter list.
   Copyright (C) 1999 Kunihiro Ishiguro

This file is part of GNU Zebra.

GNU Zebra 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 2, or (at your option) any
later version.

GNU Zebra 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 GNU Zebra; see the file COPYING.  If not, write to the Free
Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
02111-1307, USA.  */

#include <zebra.h>

#include "command.h"
#include "log.h"
#include "memory.h"
#include "buffer.h"

#include "bgpd/bgpd.h"
#include "bgpd/bgp_aspath.h"
#include "bgpd/bgp_regex.h"
#include "bgpd/bgp_filter.h"

/* List of AS filter list. */
struct as_list_list
{
  struct as_list *head;
  struct as_list *tail;
};

/* AS path filter master. */
struct as_list_master
{
  /* List of access_list which name is number. */
  struct as_list_list num;

  /* List of access_list which name is string. */
  struct as_list_list str;

  /* Hook function which is executed when new access_list is added. */
  void (*add_hook) ();

  /* Hook function which is executed when access_list is deleted. */
  void (*delete_hook) ();
};

/* Element of AS path filter. */
struct as_filter
{
  struct as_filter *next;
  struct as_filter *prev;

  enum as_filter_type type;

  regex_t *reg;
  char *reg_str;
};

enum as_list_type
{
  ACCESS_TYPE_STRING,
  ACCESS_TYPE_NUMBER
};

/* AS path filter list. */
struct as_list
{
  char *name;

  enum as_list_type type;

  struct as_list *next;
  struct as_list *prev;

  struct as_filter *head;
  struct as_filter *tail;
};

/* ip as-path access-list 10 permit AS1. */

static struct as_list_master as_list_master =
{
  {NULL, NULL},
  {NULL, NULL},
  NULL,
  NULL
};

/* Allocate new AS filter. */
struct as_filter *
as_filter_new ()
{
  struct as_filter *new;

  new = XMALLOC (MTYPE_AS_FILTER, sizeof (struct as_filter));
  memset (new, 0, sizeof (struct as_filter));
  return new;
}

/* Free allocated AS filter. */
void
as_filter_free (struct as_filter *asfilter)
{
  if (asfilter->reg)
    bgp_regex_free (asfilter->reg);
  if (asfilter->reg_str)
    XFREE (MTYPE_AS_FILTER_STR, asfilter->reg_str);
  XFREE (MTYPE_AS_FILTER, asfilter);
}

/* Make new AS filter. */
struct as_filter *
as_filter_make (regex_t *reg, char *reg_str, enum as_filter_type type)
{
  struct as_filter *asfilter;

  asfilter = as_filter_new ();
  asfilter->reg = reg;
  asfilter->type = type;
  asfilter->reg_str = XSTRDUP (MTYPE_AS_FILTER_STR, reg_str);

  return asfilter;
}

struct as_filter *
as_filter_lookup (struct as_list *aslist, char *reg_str,
		  enum as_filter_type type)
{
  struct as_filter *asfilter;

  for (asfilter = aslist->head; asfilter; asfilter = asfilter->next)
    if (strcmp (reg_str, asfilter->reg_str) == 0)
      return asfilter;
  return NULL;
}

void
as_list_filter_add (struct as_list *aslist, struct as_filter *asfilter)
{
  asfilter->next = NULL;
  asfilter->prev = aslist->tail;

  if (aslist->tail)
    aslist->tail->next = asfilter;
  else
    aslist->head = asfilter;
  aslist->tail = asfilter;
}

/* Lookup as_list from list of as_list by name. */
struct as_list *
as_list_lookup (char *name)
{
  struct as_list *aslist;

  if (name == NULL)
    return NULL;

  for (aslist = as_list_master.num.head; aslist; aslist = aslist->next)
    if (strcmp (aslist->name, name) == 0)
      return aslist;

  for (aslist = as_list_master.str.head; aslist; aslist = aslist->next)
    if (strcmp (aslist->name, name) == 0)
      return aslist;

  return NULL;
}

struct as_list *
as_list_new ()
{
  struct as_list *new;

  new = XMALLOC (MTYPE_AS_LIST, sizeof (struct as_list));
  memset (new, 0, sizeof (struct as_list));
  return new;
}

void
as_list_free (struct as_list *aslist)
{
  XFREE (MTYPE_AS_LIST, aslist);
}

/* Insert new AS list to list of as_list.  Each as_list is sorted by
   the name. */
struct as_list *
as_list_insert (char *name)
{
  int i;
  long number;
  struct as_list *aslist;
  struct as_list *point;
  struct as_list_list *list;

  /* Allocate new access_list and copy given name. */
  aslist = as_list_new ();
  aslist->name = strdup (name);

  /* If name is made by all digit character.  We treat it as
     number. */
  for (number = 0, i = 0; i < strlen (name); i++)
    {
      if (isdigit ((int) name[i]))
	number = (number * 10) + (name[i] - '0');
      else
	break;
    }

  /* In case of name is all digit character */
  if (i == strlen (name))
    {
      aslist->type = ACCESS_TYPE_NUMBER;

      /* Set access_list to number list. */
      list = &as_list_master.num;

      for (point = list->head; point; point = point->next)
	if (atol (point->name) >= number)
	  break;
    }
  else
    {
      aslist->type = ACCESS_TYPE_STRING;

      /* Set access_list to string list. */
      list = &as_list_master.str;
  
      /* Set point to insertion point. */
      for (point = list->head; point; point = point->next)
	if (strcmp (point->name, name) >= 0)
	  break;
    }

  /* In case of this is the first element of master. */
  if (list->head == NULL)
    {
      list->head = list->tail = aslist;
      return aslist;
    }

  /* In case of insertion is made at the tail of access_list. */
  if (point == NULL)
    {
      aslist->prev = list->tail;
      list->tail->next = aslist;
      list->tail = aslist;
      return aslist;
    }

  /* In case of insertion is made at the head of access_list. */
  if (point == list->head)
    {
      aslist->next = list->head;
      list->head->prev = aslist;
      list->head = aslist;
      return aslist;
    }

  /* Insertion is made at middle of the access_list. */
  aslist->next = point;
  aslist->prev = point->prev;

  if (point->prev)
    point->prev->next = aslist;
  point->prev = aslist;

  return aslist;
}

struct as_list *
as_list_get (char *name)
{
  struct as_list *aslist;

  aslist = as_list_lookup (name);
  if (aslist == NULL)
    {
      aslist = as_list_insert (name);

      /* Run hook function. */
      if (as_list_master.add_hook)
	(*as_list_master.add_hook) ();
    }

  return aslist;
}

static char *
filter_type_str (enum as_filter_type type)
{
  switch (type)
    {
    case AS_FILTER_PERMIT:
      return "permit";
      break;
    case AS_FILTER_DENY:
      return "deny";
      break;
    default:
      return "";
      break;
    }
}

void
as_list_delete (struct as_list *aslist)
{
  struct as_list_list *list;
  struct as_filter *filter, *next;

  for (filter = aslist->head; filter; filter = next)
    {
      next = filter->next;
      as_filter_free (filter);
    }

  if (aslist->type == ACCESS_TYPE_NUMBER)
    list = &as_list_master.num;
  else
    list = &as_list_master.str;

  if (aslist->next)
    aslist->next->prev = aslist->prev;
  else
    list->tail = aslist->prev;

  if (aslist->prev)
    aslist->prev->next = aslist->next;
  else
    list->head = aslist->next;

  as_list_free (aslist);
}

static int
as_list_empty (struct as_list *aslist)
{
  if (aslist->head == NULL && aslist->tail == NULL)
    return 1;
  else
    return 0;
}

void
as_list_filter_delete (struct as_list *aslist, struct as_filter *asfilter)
{
  if (asfilter->next)
    asfilter->next->prev = asfilter->prev;
  else
    aslist->tail = asfilter->prev;

  if (asfilter->prev)
    asfilter->prev->next = asfilter->next;
  else
    aslist->head = asfilter->next;

  as_filter_free (asfilter);

  /* If access_list becomes empty delete it from access_master. */