bgpd: add flowspec feature

This work is derived from a work done by China-Telecom.
That initial work can be found in [0].
As the gap between frr and quagga is important, a reworks has been
done in the meantime.
The initial work consists of bringing the following:
- Bringing the client side of flowspec.
- the enhancement of address-family ipv4/ipv6 flowspec
- partial data path handling at reception has been prepared
- the support for ipv4 flowspec or ipv6 flowspec in BGP open messages,
  and the internals of BGP has been done.
- the memory contexts necessary for flowspec has been provisioned

In addition to this work, the following has been done:
- the complement of adaptation for FS safi in bgp code
- the code checkstyle has been reworked so as to match frr checkstyle
- the processing of IPv6 FS NLRI is prevented
- the processing of FS NLRI is stopped ( temporary)

[0] https://github.com/chinatelecom-sdn-group/quagga_flowspec/

Signed-off-by: Philippe Guibert <philippe.guibert@6wind.com>
Signed-off-by: jaydom <chinatelecom-sdn-group@github.com>

1 files changed, 78 insertions, 0 deletions

diff --git a/bgpd/bgp_flowspec.c b/bgpd/bgp_flowspec.c
new file mode 100644
index 000000000..5d61175dc
--- /dev/null
+++ b/bgpd/bgp_flowspec.c
@@ -0,0 +1,78 @@
+/* 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 "math.h"
+
+#include <zebra.h>
+#include "prefix.h"
+
+#include "bgpd/bgpd.h"
+#include "bgpd/bgp_route.h"
+#include "bgpd/bgp_flowspec.h"
+#include "bgpd/bgp_flowspec_private.h"
+
+int bgp_nlri_parse_flowspec(struct peer *peer, struct attr *attr,
+			    struct bgp_nlri *packet, int withdraw)
+{
+	uint8_t *pnt;
+	uint8_t *lim;
+	afi_t afi;
+	int psize = 0;
+	uint8_t rlen;
+	struct prefix p;
+
+	/* Start processing the NLRI - there may be multiple in the MP_REACH */
+	pnt = packet->nlri;
+	lim = pnt + packet->length;
+	afi = packet->afi;
+
+	if (afi == AFI_IP6) {
+		zlog_err("BGP flowspec IPv6 not supported");
+		return -1;
+	}
+
+	if (packet->length >= FLOWSPEC_NLRI_SIZELIMIT) {
+		zlog_err("BGP flowspec nlri length maximum reached (%u)",
+			 packet->length);
+		return -1;
+	}
+
+	for (; pnt < lim; pnt += psize) {
+		/* Clear prefix structure. */
+		memset(&p, 0, sizeof(struct prefix));
+
+		/* All FlowSpec NLRI begin with length. */
+		if (pnt + 1 > lim)
+			return -1;
+
+		psize = rlen = *pnt++;
+
+		/* When packet overflow occur return immediately. */
+		if (pnt + psize > lim) {
+			zlog_err("Flowspec NLRI length inconsistent ( size %u seen)",
+				 psize);
+			return -1;
+		}
+		/* TODO: validate prefix
+		 * and add to FIB
+		 */
+	}
+	return 0;
+}