bgp_community.c

/* Community attribute related functions.
 * Copyright (C) 1998, 2001 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 this program; see the file COPYING; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <zebra.h>

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

#include "bgpd/bgp_memory.h"
#include "bgpd/bgp_community.h"

/* Hash of community attribute. */
static struct hash *comhash;

/* Allocate a new communities value.  */
static struct community *community_new(void)
{
	return (struct community *)XCALLOC(MTYPE_COMMUNITY,
					   sizeof(struct community));
}

/* Free communities value.  */
void community_free(struct community *com)
{
	if (com->val)
		XFREE(MTYPE_COMMUNITY_VAL, com->val);
	if (com->str)
		XFREE(MTYPE_COMMUNITY_STR, com->str);

	if (com->json) {
		json_object_free(com->json);
		com->json = NULL;
	}

	XFREE(MTYPE_COMMUNITY, com);
}

/* Add one community value to the community. */
static void community_add_val(struct community *com, u_int32_t val)
{
	com->size++;
	if (com->val)
		com->val = XREALLOC(MTYPE_COMMUNITY_VAL, com->val,
				    com_length(com));
	else
		com->val = XMALLOC(MTYPE_COMMUNITY_VAL, com_length(com));

	val = htonl(val);
	memcpy(com_lastval(com), &val, sizeof(u_int32_t));
}

/* Delete one community. */
void community_del_val(struct community *com, u_int32_t *val)
{
	int i = 0;
	int c = 0;

	if (!com->val)
		return;

	while (i < com->size) {
		if (memcmp(com->val + i, val, sizeof(u_int32_t)) == 0) {
			c = com->size - i - 1;

			if (c > 0)
				memmove(com->val + i, com->val + (i + 1),
					c * sizeof(*val));

			com->size--;

			if (com->size > 0)
				com->val = XREALLOC(MTYPE_COMMUNITY_VAL,
						    com->val, com_length(com));
			else {
				XFREE(MTYPE_COMMUNITY_VAL, com->val);
				com->val = NULL;
			}
			return;
		}
		i++;
	}
}

/* Delete all communities listed in com2 from com1 */
struct community *community_delete(struct community *com1,
				   struct community *com2)
{
	int i = 0;

	while (i < com2->size) {
		community_del_val(com1, com2->val + i);
		i++;
	}

	return com1;
}

/* Callback function from qsort(). */
static int community_compare(const void *a1, const void *a2)
{
	u_int32_t v1;
	u_int32_t v2;

	memcpy(&v1, a1, sizeof(u_int32_t));
	memcpy(&v2, a2, sizeof(u_int32_t));
	v1 = ntohl(v1);
	v2 = ntohl(v2);

	if (v1 < v2)
		return -1;
	if (v1 > v2)
		return 1;
	return 0;
}

int community_include(struct community *com, u_int32_t val)
{
	int i;

	val = htonl(val);

	for (i = 0; i < com->size; i++)
		if (memcmp(&val, com_nthval(com, i), sizeof(u_int32_t)) == 0)
			return 1;

	return 0;
}

u_int32_t community_val_get(struct community *com, int i)
{
	u_char *p;
	u_int32_t val;

	p = (u_char *)com->val;
	p += (i * 4);

	memcpy(&val, p, sizeof(u_int32_t));

	return ntohl(val);
}

/* Sort and uniq given community. */
struct community *community_uniq_sort(struct community *com)
{
	int i;
	struct community *new;
	u_int32_t val;

	if (!com)
		return NULL;

	new = community_new();
	;
	new->json = NULL;

	for (i = 0; i < com->size; i++) {
		val = community_val_get(com, i);

		if (!community_include(new, val))
			community_add_val(new, val);
	}

	qsort(new->val, new->size, sizeof(u_int32_t), community_compare);

	return new;
}

/* Convert communities attribute to string.

   For Well-known communities value, below keyword is used.

   0x0             "internet"
   0xFFFFFF01      "no-export"
   0xFFFFFF02      "no-advertise"
   0xFFFFFF03      "local-AS"

   For other values, "AS:VAL" format is used.  */
static void set_community_string(struct community *com)
{
	int i;
	char *str;
	char *pnt;
	int len;
	int first;
	u_int32_t comval;
	u_int16_t as;
	u_int16_t val;
	json_object *json_community_list = NULL;
	json_object *json_string = NULL;

	if (!com)
		return;

	com->json = json_object_new_object();
	json_community_list = json_object_new_array();

	/* When communities attribute is empty.  */
	if (com->size == 0) {
		str = XMALLOC(MTYPE_COMMUNITY_STR, 1);
		str[0] = '\0';

		json_object_string_add(com->json, "string", "");
		json_object_object_add(com->json, "list", json_community_list);
		com->str = str;
		return;
	}

	/* Memory allocation is time consuming work.  So we calculate
	   required string length first.  */
	len = 0;

	for (i = 0; i < com->size; i++) {
		memcpy(&comval, com_nthval(com, i), sizeof(u_int32_t));
		comval = ntohl(comval);

		switch (comval) {
		case COMMUNITY_INTERNET:
			len += strlen(" internet");
			break;
		case COMMUNITY_NO_EXPORT:
			len += strlen(" no-export");
			break;
		case COMMUNITY_NO_ADVERTISE:
			len += strlen(" no-advertise");
			break;
		case COMMUNITY_LOCAL_AS:
			len += strlen(" local-AS");
			break;
		default:
			len += strlen(" 65536:65535");
			break;
		}
	}

	/* Allocate memory.  */
	str = pnt = XMALLOC(MTYPE_COMMUNITY_STR, len);
	first = 1;

	/* Fill in string.  */
	for (i = 0; i < com->size; i++) {
		memcpy(&comval, com_nthval(com, i), sizeof(u_int32_t));
		comval = ntohl(comval);

		if (first)
			first = 0;
		else
			*pnt++ = ' ';

		switch (comval) {
		case COMMUNITY_INTERNET:
			strcpy(pnt, "internet");
			pnt += strlen("internet");
			json_string = json_object_new_string("internet");
			json_object_array_add(json_community_list, json_string);
			break;
		case COMMUNITY_NO_EXPORT:
			strcpy(pnt, "no-export");
			pnt += strlen("no-export");
			json_string = json_object_new_string("noExport");
			json_object_array_add(json_community_list, json_string);
			break;
		case COMMUNITY_NO_ADVERTISE:
			strcpy(pnt, "no-advertise");
			pnt += strlen("no-advertise");
			json_string = json_object_new_string("noAdvertise");
			json_object_array_add(json_community_list, json_string);
			break;
		case COMMUNITY_LOCAL_AS:
			strcpy(pnt, "local-AS");
			pnt += strlen("local-AS");
			json_string = json_object_new_string("localAs");
			json_object_array_add(json_community_list, json_string);
			break;
		default:
			as = (comval >> 16) & 0xFFFF;
			val = comval & 0xFFFF;
			sprintf(pnt, "%u:%d", as, val);
			json_string = json_object_new_string(pnt);
			json_object_array_add(json_community_list, json_string);
			pnt += strlen(pnt);
			break;
		}
	}
	*pnt = '\0';

	json_object_string_add(com->json, "string", str);
	json_object_object_add(com->json, "list", json_community_list);
	com->str = str;
}

/* Intern communities attribute.  */
struct community *community_intern(struct community *com)
{
	struct community *find;

	/* Assert this community structure is not interned. */
	assert(com->refcnt == 0);

	/* Lookup community hash. */
	find = (struct community *)hash_get(comhash, com, hash_alloc_intern);

	/* Arguemnt com is allocated temporary.  So when it is not used in
	   hash, it should be freed.  */
	if (find != com)
		community_free(com);

	/* Increment refrence counter.  */
	find->refcnt++;

	/* Make string.  */
	if (!find->str)
		set_community_string(find);

	return find;
}

/* Free community attribute. */
void community_unintern(struct community **com)
{
	struct community *ret;

	if ((*com)->refcnt)
		(*com)->refcnt--;

	/* Pull off from hash.  */
	if ((*com)->refcnt == 0) {
		/* Community value com must exist in hash. */
		ret = (struct community *)hash_release(comhash, *com);
		assert(ret != NULL);

		community_free(*com);
		*com = NULL;
	}
}

/* Create new community attribute. */
struct community *community_parse(u_int32_t *pnt, u_short length)
{
	struct community tmp;
	struct community *new;

	/* If length is malformed return NULL. */
	if (length % 4)
		return NULL;

	/* Make temporary community for hash look up. */
	tmp.size = length / 4;
	tmp.val = pnt;

	new = community_uniq_sort(&tmp);

	return community_intern(new);
}

struct community *community_dup(struct community *com)
{
	struct community *new;

	new = XCALLOC(MTYPE_COMMUNITY, sizeof(struct community));
	new->size = com->size;
	if (new->size) {
		new->val = XMALLOC(MTYPE_COMMUNITY_VAL, com->size * 4);
		memcpy(new->val, com->val, com->size * 4);
	} else
		new->val = NULL;
	return new;
}

/* Retrun string representation of communities attribute. */
char *community_str(struct community *com)
{
	if (!com)
		return NULL;

	if (!com->str)
		set_community_string(com);
	return com->str;
}

/* Make hash value of community attribute. This function is used by
   hash package.*/
unsigned int community_hash_make(struct community *com)
{
	unsigned char *pnt = (unsigned char *)com->val;
	int size = com->size * 4;
	unsigned int key = 0;
	int c;

	for (c = 0; c < size; c += 4) {
		key += pnt[c];
		key += pnt[c + 1];
		key += pnt[c + 2];
		key += pnt[c + 3];
	}

	return key;
}

int community_match(const struct community *com1, const struct community *com2)
{
	int i = 0;
	int j = 0;

	if (com1 == NULL && com2 == NULL)
		return 1;

	if (com1 == NULL || com2 == NULL)
		return 0;

	if (com1->size < com2->size)
		return 0;

	/* Every community on com2 needs to be on com1 for this to match */
	while (i < com1->size && j < com2->size) {
		if (memcmp(com1->val + i, com2->val + j, sizeof(u_int32_t))
		    == 0)
			j++;
		i++;
	}

	if (j == com2->size)
		return 1;
	else
		return 0;
}

/* If two aspath have same value then return 1 else return 0. This
   function is used by hash package. */
int community_cmp(const struct community *com1, const struct community *com2)
{
	if (com1 == NULL && com2 == NULL)
		return 1;
	if (com1 == NULL || com2 == NULL)
		return 0;

	if (com1->size == com2->size)
		if (memcmp(com1->val, com2->val, com1->size * 4) == 0)
			return 1;
	return 0;
}

/* Add com2 to the end of com1. */
struct community *community_merge(struct community *com1,
				  struct community *com2)
{
	if (com1->val)
		com1->val = XREALLOC(MTYPE_COMMUNITY_VAL, com1->val,
				     (com1->size + com2->size) * 4);
	else
		com1->val = XMALLOC(MTYPE_COMMUNITY_VAL,
				    (com1->size + com2->size) * 4);

	memcpy(com1->val + com1->size, com2->val, com2->size * 4);
	com1->size += com2->size;

	return com1;
}

/* Community token enum. */
enum community_token {
	community_token_val,
	community_token_no_export,
	community_token_no_advertise,
	community_token_local_as,
	community_token_unknown
};

/* Get next community token from string. */
static const char *
community_gettoken(const char *buf, enum community_token *token, u_int32_t *val)
{
	const char *p = buf;

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

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

	/* Well known community string check. */
	if (isalpha((int)*p)) {
		if (strncmp(p, "internet", strlen("internet")) == 0) {
			*val = COMMUNITY_INTERNET;
			*token = community_token_no_export;
			p += strlen("internet");
			return p;
		}
		if (strncmp(p, "no-export", strlen("no-export")) == 0) {
			*val = COMMUNITY_NO_EXPORT;
			*token = community_token_no_export;
			p += strlen("no-export");
			return p;
		}
		if (strncmp(p, "no-advertise", strlen("no-advertise")) == 0) {
			*val = COMMUNITY_NO_ADVERTISE;
			*token = community_token_no_advertise;
			p += strlen("no-advertise");
			return p;
		}
		if (strncmp(p, "local-AS", strlen("local-AS")) == 0) {
			*val = COMMUNITY_LOCAL_AS;
			*token = community_token_local_as;
			p += strlen("local-AS");
			return p;
		}

		/* Unknown string. */
		*token = community_token_unknown;
		return NULL;
	}

	/* Community value. */
	if (isdigit((int)*p)) {
		int separator = 0;
		int digit = 0;
		u_int32_t community_low = 0;
		u_int32_t community_high = 0;

		while (isdigit((int)*p) || *p == ':') {
			if (*p == ':') {
				if (separator) {
					*token = community_token_unknown;
					return NULL;
				} else {
					separator = 1;
					digit = 0;

					if (community_low > UINT16_MAX) {
						*token =
							community_token_unknown;
						return NULL;
					}

					community_high = community_low << 16;
					community_low = 0;
				}
			} else {
				digit = 1;
				community_low *= 10;
				community_low += (*p - '0');
			}
			p++;
		}
		if (!digit) {
			*token = community_token_unknown;
			return NULL;
		}

		if (community_low > UINT16_MAX) {
			*token = community_token_unknown;
			return NULL;
		}

		*val = community_high + community_low;
		*token = community_token_val;
		return p;
	}
	*token = community_token_unknown;
	return NULL;
}

/* convert string to community structure */
struct community *community_str2com(const char *str)
{
	struct community *com = NULL;
	struct community *com_sort = NULL;
	u_int32_t val = 0;
	enum community_token token = community_token_unknown;

	do {
		str = community_gettoken(str, &token, &val);

		switch (token) {
		case community_token_val:
		case community_token_no_export:
		case community_token_no_advertise:
		case community_token_local_as:
			if (com == NULL) {
				com = community_new();
				com->json = NULL;
			}
			community_add_val(com, val);
			break;
		case community_token_unknown:
		default:
			if (com)
				community_free(com);
			return NULL;
		}
	} while (str);

	if (!com)
		return NULL;

	com_sort = community_uniq_sort(com);
	community_free(com);

	return com_sort;
}

/* Return communities hash entry count.  */
unsigned long community_count(void)
{
	return comhash->count;
}

/* Return communities hash.  */
struct hash *community_hash(void)
{
	return comhash;
}

/* Initialize comminity related hash. */
void community_init(void)
{
	comhash = hash_create(
		(unsigned int (*)(void *))community_hash_make,
		(int (*)(const void *, const void *))community_cmp, NULL);
}

void community_finish(void)
{
	hash_free(comhash);
	comhash = NULL;
}