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/* BGP FlowSpec for packet handling
* Portions:
* Copyright (C) 2017 ChinaTelecom SDN Group
* Copyright (C) 2018 6WIND
*
* FRRouting 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.
*
* FRRouting 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 <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;
int ret;
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)
ret = bgp_update(peer, &p, 0, attr,
afi, safi,
ZEBRA_ROUTE_BGP, BGP_ROUTE_NORMAL,
NULL, NULL, 0, 0, NULL);
else
ret = bgp_withdraw(peer, &p, 0, attr,
afi, safi,
ZEBRA_ROUTE_BGP, BGP_ROUTE_NORMAL,
NULL, NULL, 0, NULL);
if (ret) {
flog_err(EC_BGP_FLOWSPEC_INSTALLATION,
"Flowspec NLRI failed to be %s.",
attr ? "added" : "withdrawn");
return BGP_NLRI_PARSE_ERROR;
}
}
return BGP_NLRI_PARSE_OK;
}
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