bgp_ecommunity.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

/* BGP Extended Communities Attribute
   Copyright (C) 2000 Kunihiro Ishiguro <[e-mail]>

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 "hash.h"
#include "memory.h"
#include "prefix.h"
#include "command.h"

#include "bgpd/bgpd.h"
#include "bgpd/bgp_ecommunity.h"

/* Hash of community attribute. */
struct hash *ecomhash;

/* Allocate a new ecommunities.  */
struct ecommunity *
ecommunity_new ()
{
  return (struct ecommunity *) XCALLOC (MTYPE_ECOMMUNITY,
					sizeof (struct ecommunity));
}

/* Allocate ecommunities.  */
void
ecommunity_free (struct ecommunity *ecom)
{
  if (ecom->val)
    XFREE (MTYPE_ECOMMUNITY_VAL, ecom->val);
  if (ecom->str)
    XFREE (MTYPE_ECOMMUNITY_STR, ecom->str);
  XFREE (MTYPE_ECOMMUNITY, ecom);
}

/* Add a new Extended Communities value to Extended Communities
   Attribute structure.  When the value is already exists in the
   structure, we don't add the value.  Newly added value is sorted by
   numerical order.  When the value is added to the structure return 1
   else return 0.  */
static int
ecommunity_add_val (struct ecommunity *ecom, struct ecommunity_val *eval)
{
  u_char *p;
  int ret;
  int c;

  /* When this is fist value, just add it.  */
  if (ecom->val == NULL)
    {
      ecom->size++;
      ecom->val = XMALLOC (MTYPE_ECOMMUNITY_VAL, ecom_length (ecom));
      memcpy (ecom->val, eval->val, ECOMMUNITY_SIZE);
      return 1;
    }

  /* If the value already exists in the structure return 0.  */
  c = 0;
  for (p = ecom->val; c < ecom->size; p += ECOMMUNITY_SIZE, c++)
    {
      ret = memcmp (p, eval->val, ECOMMUNITY_SIZE);
      if (ret == 0)
        return 0;
      if (ret > 0)
        break;
    }

  /* Add the value to the structure with numerical sorting.  */
  ecom->size++;
  ecom->val = XREALLOC (MTYPE_ECOMMUNITY_VAL, ecom->val, ecom_length (ecom));

  memmove (ecom->val + (c + 1) * ECOMMUNITY_SIZE,
	   ecom->val + c * ECOMMUNITY_SIZE,
	   (ecom->size - 1 - c) * ECOMMUNITY_SIZE);
  memcpy (ecom->val + c * ECOMMUNITY_SIZE, eval->val, ECOMMUNITY_SIZE);

  return 1;
}

/* This function takes pointer to Extended Communites strucutre then
   create a new Extended Communities structure by uniq and sort each
   Exteneded Communities value.  */
struct ecommunity *
ecommunity_uniq_sort (struct ecommunity *ecom)
{
  int i;
  struct ecommunity *new;
  struct ecommunity_val *eval;
  
  if (! ecom)
    return NULL;
  
  new = ecommunity_new ();;
  
  for (i = 0; i < ecom->size; i++)
    {
      eval = (struct ecommunity_val *) (ecom->val + (i * ECOMMUNITY_SIZE));
      ecommunity_add_val (new, eval);
    }
  return new;
}

/* Parse Extended Communites Attribute in BGP packet.  */
struct ecommunity *
ecommunity_parse (char *pnt, u_short length)
{
  struct ecommunity tmp;
  struct ecommunity *new;

  /* Length check.  */
  if (length % ECOMMUNITY_SIZE)
    return NULL;

  /* Prepare tmporary structure for making a new Extended Communities
     Attribute.  */
  tmp.size = length / ECOMMUNITY_SIZE;
  tmp.val = pnt;

  /* Create a new Extended Communities Attribute by uniq and sort each
     Extended Communities value  */
  new = ecommunity_uniq_sort (&tmp);

  return ecommunity_intern (new);
}

/* Duplicate the Extended Communities Attribute structure.  */
struct ecommunity *
ecommunity_dup (struct ecommunity *ecom)
{
  struct ecommunity *new;

  new = XCALLOC (MTYPE_ECOMMUNITY, sizeof (struct ecommunity));
  new->size = ecom->size;
  if (new->size)
    {
      new->val = XMALLOC (MTYPE_ECOMMUNITY_VAL, ecom->size * ECOMMUNITY_SIZE);
      memcpy (new->val, ecom->val, ecom->size * ECOMMUNITY_SIZE);
    }
  else
    new->val = NULL;
  return new;
}

/* Retrun string representation of communities attribute. */
char *
ecommunity_str (struct ecommunity *ecom)
{
  if (! ecom->str)
    ecom->str = ecommunity_ecom2str (ecom, ECOMMUNITY_FORMAT_DISPLAY);
  return ecom->str;
}

/* Merge two Extended Communities Attribute structure.  */
struct ecommunity *
ecommunity_merge (struct ecommunity *ecom1, struct ecommunity *ecom2)
{
  if (ecom1->val)
    ecom1->val = XREALLOC (MTYPE_ECOMMUNITY_VAL, ecom1->val, 
			   (ecom1->size + ecom2->size) * ECOMMUNITY_SIZE);
  else
    ecom1->val = XMALLOC (MTYPE_ECOMMUNITY_VAL,
			  (ecom1->size + ecom2->size) * ECOMMUNITY_SIZE);

  memcpy (ecom1->val + (ecom1->size * ECOMMUNITY_SIZE),
	  ecom2->val, ecom2->size * ECOMMUNITY_SIZE);
  ecom1->size += ecom2->size;

  return ecom1;
}

/* Intern Extended Communities Attribute.  */
struct ecommunity *
ecommunity_intern (struct ecommunity *ecom)
{
  struct ecommunity *find;

  assert (ecom->refcnt == 0);

  find = (struct ecommunity *) hash_get (ecomhash, ecom, hash_alloc_intern);

  if (find != ecom)
    ecommunity_free (ecom);

  find->refcnt++;

  if (! find->str)
    find->str = ecommunity_ecom2str (find, ECOMMUNITY_FORMAT_DISPLAY);

  return find;
}

/* Unintern Extended Communities Attribute.  */
void
ecommunity_unintern (struct ecommunity *ecom)
{
  struct ecommunity *ret;

  if (ecom->refcnt)
    ecom->refcnt--;

  /* Pull off from hash.  */
  if (ecom->refcnt == 0)
    {
      /* Extended community must be in the hash.  */
      ret = (struct ecommunity *) hash_release (ecomhash, ecom);
      assert (ret != NULL);

      ecommunity_free (ecom);
    }
}

/* Utinity function to make hash key.  */
unsigned int
ecommunity_hash_make (struct ecommunity *ecom)
{
  int c;
  unsigned int key;
  unsigned char *pnt;

  key = 0;
  pnt = ecom->val;
  
  for (c = 0; c < ecom->size * ECOMMUNITY_SIZE; c++)
    key += pnt[c];

  return key;
}

/* Compare two Extended Communities Attribute structure.  */
int
ecommunity_cmp (struct ecommunity *ecom1, struct ecommunity *ecom2)
{
  if (ecom1->size == ecom2->size
      && memcmp (ecom1->val, ecom2->val, ecom1->size * ECOMMUNITY_SIZE) == 0)
    return 1;
  return 0;
}

/* Initialize Extended Comminities related hash. */
void
ecommunity_init ()
{
  ecomhash = hash_create (ecommunity_hash_make, ecommunity_cmp);
}

/* Extended Communities token enum. */
enum ecommunity_token
{
  ecommunity_token_rt,
  ecommunity_token_soo,
  ecommunity_token_val,
  ecommunity_token_unknown
};

/* Get next Extended Communities token from the string. */
char *
ecommunity_gettoken (char *str, struct ecommunity_val *eval,
		     enum ecommunity_token *token)
{
  int ret;
  int dot = 0;
  int digit = 0;
  int separator = 0;
  u_int32_t val_low = 0;
  u_int32_t val_high = 0;
  char *p = str;
  struct in_addr ip;
  char ipstr[INET_ADDRSTRLEN + 1];

  /* Skip white space. */
  while (isspace ((int) *p))
    {
      p++;
      str++;
    }

  /* Check the end of the line. */
  if (*p == '\0')
    return NULL;

  /* "rt" and "soo" keyword parse. */
  if (! isdigit ((int) *p)) 
    {
      /* "rt" match check.  */
      if (tolower ((int) *p) == 'r')
	{
	  p++;
 	  if (tolower ((int) *p) == 't')
	    {
	      p++;
	      *token = ecommunity_token_rt;
	      return p;
	    }
	  if (isspace ((int) *p) || *p == '\0')
	    {
	      *token = ecommunity_token_rt;
	      return p;
	    }
	  goto error;
	}
      /* "soo" match check.  */
      else if (tolower ((int) *p) == 's')
	{
	  p++;
 	  if (tolower ((int) *p) == 'o')
	    {
	      p++;
	      if (tolower ((int) *p) == 'o')
		{
		  p++;
		  *token = ecommunity_token_soo;
		  return p;
		}
	      if (isspace ((int) *p) || *p == '\0')
		{
		  *token = ecommunity_token_soo;
		  return p;
		}
	      goto error;
	    }
	  if (isspace ((int) *p) || *p == '\0')
	    {
	      *token = ecommunity_token_soo;
	      return p;