[mirror_frr.git] / bgpd / bgp_flowspec.c

// SPDX-License-Identifier: GPL-2.0-or-later
/* BGP FlowSpec for packet handling
 * Portions:
 *     Copyright (C) 2017 ChinaTelecom SDN Group
 *     Copyright (C) 2018 6WIND
 */

#include <zebra.h>
#include <math.h>

#include "prefix.h"
#include "lib_errors.h"

#include "bgpd/bgpd.h"
#include "bgpd/bgp_route.h"
#include "bgpd/bgp_flowspec.h"
#include "bgpd/bgp_flowspec_util.h"
#include "bgpd/bgp_flowspec_private.h"
#include "bgpd/bgp_ecommunity.h"
#include "bgpd/bgp_debug.h"
#include "bgpd/bgp_errors.h"

static int bgp_fs_nlri_validate(uint8_t *nlri_content, uint32_t len,
				afi_t afi)
{
	uint32_t offset = 0;
	int type;
	int ret = 0, error = 0;

	while (offset < len-1) {
		type = nlri_content[offset];
		offset++;
		switch (type) {
		case FLOWSPEC_DEST_PREFIX:
		case FLOWSPEC_SRC_PREFIX:
			ret = bgp_flowspec_ip_address(
						BGP_FLOWSPEC_VALIDATE_ONLY,
						nlri_content + offset,
						len - offset, NULL, &error,
						afi, NULL);
			break;
		case FLOWSPEC_FLOW_LABEL:
			if (afi == AFI_IP)
				return -1;
			ret = bgp_flowspec_op_decode(BGP_FLOWSPEC_VALIDATE_ONLY,
						   nlri_content + offset,
						   len - offset, NULL, &error);
			break;
		case FLOWSPEC_IP_PROTOCOL:
		case FLOWSPEC_PORT:
		case FLOWSPEC_DEST_PORT:
		case FLOWSPEC_SRC_PORT:
		case FLOWSPEC_ICMP_TYPE:
		case FLOWSPEC_ICMP_CODE:
			ret = bgp_flowspec_op_decode(BGP_FLOWSPEC_VALIDATE_ONLY,
						   nlri_content + offset,
						   len - offset, NULL, &error);
			break;
		case FLOWSPEC_TCP_FLAGS:
		case FLOWSPEC_FRAGMENT:
			ret = bgp_flowspec_bitmask_decode(
						   BGP_FLOWSPEC_VALIDATE_ONLY,
						   nlri_content + offset,
						   len - offset, NULL, &error);
			break;
		case FLOWSPEC_PKT_LEN:
		case FLOWSPEC_DSCP:
			ret = bgp_flowspec_op_decode(
						BGP_FLOWSPEC_VALIDATE_ONLY,
						nlri_content + offset,
						len - offset, NULL, &error);
			break;
		default:
			error = -1;
			break;
		}
		offset += ret;
		if (error < 0)
			break;
	}
	return error;
}

int bgp_nlri_parse_flowspec(struct peer *peer, struct attr *attr,
			    struct bgp_nlri *packet, bool withdraw)
{
	uint8_t *pnt;
	uint8_t *lim;
	afi_t afi;
	safi_t safi;
	int psize = 0;
	struct prefix p;
	void *temp;

	/* Start processing the NLRI - there may be multiple in the MP_REACH */
	pnt = packet->nlri;
	lim = pnt + packet->length;
	afi = packet->afi;
	safi = packet->safi;

	/*
	 * All other AFI/SAFI's treat no attribute as a implicit
	 * withdraw.  Flowspec should as well.
	 */
	if (!attr)
		withdraw = true;

	if (packet->length >= FLOWSPEC_NLRI_SIZELIMIT_EXTENDED) {
		flog_err(EC_BGP_FLOWSPEC_PACKET,
			 "BGP flowspec nlri length maximum reached (%u)",
			 packet->length);
		return BGP_NLRI_PARSE_ERROR_FLOWSPEC_NLRI_SIZELIMIT;
	}

	for (; pnt < lim; pnt += psize) {
		/* Clear prefix structure. */
		memset(&p, 0, sizeof(p));

		/* All FlowSpec NLRI begin with length. */
		if (pnt + 1 > lim)
			return BGP_NLRI_PARSE_ERROR_PACKET_OVERFLOW;

		psize = *pnt++;
		if (psize >= FLOWSPEC_NLRI_SIZELIMIT) {
			psize &= 0x0f;
			psize = psize << 8;
			psize |= *pnt++;
		}
		/* When packet overflow occur return immediately. */
		if (pnt + psize > lim) {
			flog_err(
				EC_BGP_FLOWSPEC_PACKET,
				"Flowspec NLRI length inconsistent ( size %u seen)",
				psize);
			return BGP_NLRI_PARSE_ERROR_PACKET_OVERFLOW;
		}

		if (psize == 0) {
			flog_err(EC_BGP_FLOWSPEC_PACKET,
				 "Flowspec NLRI length 0 which makes no sense");
			return BGP_NLRI_PARSE_ERROR_PACKET_OVERFLOW;
		}

		if (bgp_fs_nlri_validate(pnt, psize, afi) < 0) {
			flog_err(
				EC_BGP_FLOWSPEC_PACKET,
				"Bad flowspec format or NLRI options not supported");
			return BGP_NLRI_PARSE_ERROR_FLOWSPEC_BAD_FORMAT;
		}
		p.family = AF_FLOWSPEC;
		p.prefixlen = 0;
		/* Flowspec encoding is in bytes */
		p.u.prefix_flowspec.prefixlen = psize;
		p.u.prefix_flowspec.family = afi2family(afi);
		temp = XCALLOC(MTYPE_TMP, psize);
		memcpy(temp, pnt, psize);
		p.u.prefix_flowspec.ptr = (uintptr_t) temp;

		if (BGP_DEBUG(flowspec, FLOWSPEC)) {
			char return_string[BGP_FLOWSPEC_NLRI_STRING_MAX];
			char local_string[BGP_FLOWSPEC_NLRI_STRING_MAX*2+16];
			char ec_string[BGP_FLOWSPEC_NLRI_STRING_MAX];
			char *s = NULL;

			bgp_fs_nlri_get_string((unsigned char *)
					       p.u.prefix_flowspec.ptr,
					       p.u.prefix_flowspec.prefixlen,
					       return_string,
					       NLRI_STRING_FORMAT_MIN, NULL,
					       afi);
			snprintf(ec_string, sizeof(ec_string),
				 "EC{none}");
			if (attr && bgp_attr_get_ecommunity(attr)) {
				s = ecommunity_ecom2str(
					bgp_attr_get_ecommunity(attr),
					ECOMMUNITY_FORMAT_ROUTE_MAP, 0);
				snprintf(ec_string, sizeof(ec_string),
					 "EC{%s}",
					s == NULL ? "none" : s);

				if (s)
					ecommunity_strfree(&s);
			}
			snprintf(local_string, sizeof(local_string),
				 "FS Rx %s %s %s %s", withdraw ?
				 "Withdraw":"Update",
				 afi2str(afi), return_string,
				 attr != NULL ? ec_string : "");
			zlog_info("%s", local_string);
		}
		/* Process the route. */
		if (!withdraw)
			bgp_update(peer, &p, 0, attr, afi, safi,
				   ZEBRA_ROUTE_BGP, BGP_ROUTE_NORMAL, NULL,
				   NULL, 0, 0, NULL);
		else
			bgp_withdraw(peer, &p, 0, afi, safi, ZEBRA_ROUTE_BGP,
				     BGP_ROUTE_NORMAL, NULL, NULL, 0, NULL);
	}
	return BGP_NLRI_PARSE_OK;
}
Commit	Line	Data
acddc0ed	1	// SPDX-License-Identifier: GPL-2.0-or-later
7c40bf39	2	/* BGP FlowSpec for packet handling
	3	* Portions:
	4	* Copyright (C) 2017 ChinaTelecom SDN Group
	5	* Copyright (C) 2018 6WIND
7c40bf39	6	*/
7c40bf39	7
7c40bf39	8	#include <zebra.h>
b45ac5f5 DL	9	#include <math.h>
b45ac5f5 DL	10
7c40bf39	11	#include "prefix.h"
02705213	12	#include "lib_errors.h"
7c40bf39	13
	14	#include "bgpd/bgpd.h"
	15	#include "bgpd/bgp_route.h"
	16	#include "bgpd/bgp_flowspec.h"
fc836540	17	#include "bgpd/bgp_flowspec_util.h"
7c40bf39	18	#include "bgpd/bgp_flowspec_private.h"
268e1b9b PG	19	#include "bgpd/bgp_ecommunity.h"
268e1b9b PG	20	#include "bgpd/bgp_debug.h"
4f3be667	21	#include "bgpd/bgp_errors.h"
7c40bf39	22
1840384b PG	23	static int bgp_fs_nlri_validate(uint8_t *nlri_content, uint32_t len,
1840384b PG	24	afi_t afi)
fc836540 PG	25	{
	26	uint32_t offset = 0;
	27	int type;
	28	int ret = 0, error = 0;
	29
	30	while (offset < len-1) {
	31	type = nlri_content[offset];
	32	offset++;
	33	switch (type) {
	34	case FLOWSPEC_DEST_PREFIX:
	35	case FLOWSPEC_SRC_PREFIX:
	36	ret = bgp_flowspec_ip_address(
	37	BGP_FLOWSPEC_VALIDATE_ONLY,
	38	nlri_content + offset,
1840384b	39	len - offset, NULL, &error,
9cec4121	40	afi, NULL);
fc836540	41	break;
40881800 PG	42	case FLOWSPEC_FLOW_LABEL:
	43	if (afi == AFI_IP)
	44	return -1;
	45	ret = bgp_flowspec_op_decode(BGP_FLOWSPEC_VALIDATE_ONLY,
	46	nlri_content + offset,
	47	len - offset, NULL, &error);
	48	break;
fc836540 PG	49	case FLOWSPEC_IP_PROTOCOL:
	50	case FLOWSPEC_PORT:
	51	case FLOWSPEC_DEST_PORT:
	52	case FLOWSPEC_SRC_PORT:
	53	case FLOWSPEC_ICMP_TYPE:
	54	case FLOWSPEC_ICMP_CODE:
	55	ret = bgp_flowspec_op_decode(BGP_FLOWSPEC_VALIDATE_ONLY,
	56	nlri_content + offset,
	57	len - offset, NULL, &error);
	58	break;
	59	case FLOWSPEC_TCP_FLAGS:
588ec356 PG	60	case FLOWSPEC_FRAGMENT:
588ec356 PG	61	ret = bgp_flowspec_bitmask_decode(
fc836540 PG	62	BGP_FLOWSPEC_VALIDATE_ONLY,
	63	nlri_content + offset,
	64	len - offset, NULL, &error);
	65	break;
	66	case FLOWSPEC_PKT_LEN:
	67	case FLOWSPEC_DSCP:
	68	ret = bgp_flowspec_op_decode(
	69	BGP_FLOWSPEC_VALIDATE_ONLY,
	70	nlri_content + offset,
	71	len - offset, NULL, &error);
	72	break;
fc836540 PG	73	default:
	74	error = -1;
	75	break;
	76	}
	77	offset += ret;
	78	if (error < 0)
	79	break;
	80	}
	81	return error;
	82	}
	83
7c40bf39	84	int bgp_nlri_parse_flowspec(struct peer peer, struct attr attr,
aa056a2a	85	struct bgp_nlri *packet, bool withdraw)
7c40bf39	86	{
	87	uint8_t *pnt;
	88	uint8_t *lim;
	89	afi_t afi;
fc836540	90	safi_t safi;
7c40bf39	91	int psize = 0;
7c40bf39	92	struct prefix p;
fc836540	93	void *temp;
7c40bf39	94
	95	/* Start processing the NLRI - there may be multiple in the MP_REACH */
	96	pnt = packet->nlri;
	97	lim = pnt + packet->length;
	98	afi = packet->afi;
fc836540	99	safi = packet->safi;
7c40bf39	100
cfd04dcb DS	101	/*
	102	* All other AFI/SAFI's treat no attribute as a implicit
	103	* withdraw. Flowspec should as well.
	104	*/
	105	if (!attr)
aa056a2a	106	withdraw = true;
cfd04dcb	107
3255e756	108	if (packet->length >= FLOWSPEC_NLRI_SIZELIMIT_EXTENDED) {
e50f7cfd	109	flog_err(EC_BGP_FLOWSPEC_PACKET,
1c50c1c0 QY	110	"BGP flowspec nlri length maximum reached (%u)",
1c50c1c0 QY	111	packet->length);
513386b5	112	return BGP_NLRI_PARSE_ERROR_FLOWSPEC_NLRI_SIZELIMIT;
7c40bf39	113	}
	114
	115	for (; pnt < lim; pnt += psize) {
	116	/* Clear prefix structure. */
6006b807	117	memset(&p, 0, sizeof(p));
7c40bf39	118
	119	/* All FlowSpec NLRI begin with length. */
	120	if (pnt + 1 > lim)
513386b5	121	return BGP_NLRI_PARSE_ERROR_PACKET_OVERFLOW;
7c40bf39	122
3f54c705	123	psize = *pnt++;
3255e756 PG	124	if (psize >= FLOWSPEC_NLRI_SIZELIMIT) {
	125	psize &= 0x0f;
	126	psize = psize << 8;
	127	psize \|= *pnt++;
	128	}
7c40bf39	129	/* When packet overflow occur return immediately. */
7c40bf39	130	if (pnt + psize > lim) {
1c50c1c0 QY	131	flog_err(
	132	EC_BGP_FLOWSPEC_PACKET,
	133	"Flowspec NLRI length inconsistent ( size %u seen)",
	134	psize);
513386b5	135	return BGP_NLRI_PARSE_ERROR_PACKET_OVERFLOW;
7c40bf39	136	}
0b999c88 DS	137
	138	if (psize == 0) {
	139	flog_err(EC_BGP_FLOWSPEC_PACKET,
	140	"Flowspec NLRI length 0 which makes no sense");
	141	return BGP_NLRI_PARSE_ERROR_PACKET_OVERFLOW;
	142	}
	143
1840384b	144	if (bgp_fs_nlri_validate(pnt, psize, afi) < 0) {
1c50c1c0 QY	145	flog_err(
	146	EC_BGP_FLOWSPEC_PACKET,
	147	"Bad flowspec format or NLRI options not supported");
513386b5	148	return BGP_NLRI_PARSE_ERROR_FLOWSPEC_BAD_FORMAT;
fc836540 PG	149	}
	150	p.family = AF_FLOWSPEC;
	151	p.prefixlen = 0;
	152	/* Flowspec encoding is in bytes */
	153	p.u.prefix_flowspec.prefixlen = psize;
1840384b	154	p.u.prefix_flowspec.family = afi2family(afi);
fc836540 PG	155	temp = XCALLOC(MTYPE_TMP, psize);
	156	memcpy(temp, pnt, psize);
	157	p.u.prefix_flowspec.ptr = (uintptr_t) temp;
268e1b9b PG	158
	159	if (BGP_DEBUG(flowspec, FLOWSPEC)) {
	160	char return_string[BGP_FLOWSPEC_NLRI_STRING_MAX];
a2dc7057	161	char local_string[BGP_FLOWSPEC_NLRI_STRING_MAX*2+16];
268e1b9b PG	162	char ec_string[BGP_FLOWSPEC_NLRI_STRING_MAX];
	163	char *s = NULL;
	164
	165	bgp_fs_nlri_get_string((unsigned char *)
	166	p.u.prefix_flowspec.ptr,
	167	p.u.prefix_flowspec.prefixlen,
	168	return_string,
1840384b PG	169	NLRI_STRING_FORMAT_MIN, NULL,
1840384b PG	170	afi);
ff44f570	171	snprintf(ec_string, sizeof(ec_string),
268e1b9b	172	"EC{none}");
b53e67a3 DA	173	if (attr && bgp_attr_get_ecommunity(attr)) {
	174	s = ecommunity_ecom2str(
	175	bgp_attr_get_ecommunity(attr),
	176	ECOMMUNITY_FORMAT_ROUTE_MAP, 0);
ff44f570	177	snprintf(ec_string, sizeof(ec_string),
268e1b9b PG	178	"EC{%s}",
268e1b9b PG	179	s == NULL ? "none" : s);
c7ee6c35 DS	180
	181	if (s)
	182	ecommunity_strfree(&s);
268e1b9b	183	}
ff44f570	184	snprintf(local_string, sizeof(local_string),
268e1b9b PG	185	"FS Rx %s %s %s %s", withdraw ?
	186	"Withdraw":"Update",
	187	afi2str(afi), return_string,
	188	attr != NULL ? ec_string : "");
	189	zlog_info("%s", local_string);
	190	}
fc836540 PG	191	/* Process the route. */
fc836540 PG	192	if (!withdraw)
367b458c DS	193	bgp_update(peer, &p, 0, attr, afi, safi,
	194	ZEBRA_ROUTE_BGP, BGP_ROUTE_NORMAL, NULL,
	195	NULL, 0, 0, NULL);
fc836540	196	else
bf0c6163 DA	197	bgp_withdraw(peer, &p, 0, afi, safi, ZEBRA_ROUTE_BGP,
bf0c6163 DA	198	BGP_ROUTE_NORMAL, NULL, NULL, 0, NULL);
7c40bf39	199	}
513386b5	200	return BGP_NLRI_PARSE_OK;
7c40bf39	201	}