Re: [PATCH v2 iproute2 3/3] bridge: mst: Add get/set support for MST states

Allow a port's spanning tree state to be modified on a per-MSTI basis,
and support dumping the current MST states for every port and MSTI.

Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
---
 bridge/Makefile    |   2 +-
 bridge/br_common.h |   1 +
 bridge/bridge.c    |   3 +-
 bridge/mst.c       | 262 +++++++++++++++++++++++++++++++++++++++++++++
 man/man8/bridge.8  |  57 ++++++++++
 5 files changed, 323 insertions(+), 2 deletions(-)
 create mode 100644 bridge/mst.c

diff --git a/bridge/Makefile b/bridge/Makefile
index 01f8a455..4c57df43 100644
--- a/bridge/Makefile
+++ b/bridge/Makefile

@@ -1,5 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0
-BROBJ = bridge.o fdb.o monitor.o link.o mdb.o vlan.o vni.o
+BROBJ = bridge.o fdb.o monitor.o link.o mdb.o mst.o vlan.o vni.o
 
 include ../config.mk
 

diff --git a/bridge/br_common.h b/bridge/br_common.h
index 704e76b0..3a0cf882 100644
--- a/bridge/br_common.h
+++ b/bridge/br_common.h

@@ -20,6 +20,7 @@ void print_headers(FILE *fp, const char *label);
 int do_fdb(int argc, char **argv);
 int do_mdb(int argc, char **argv);
 int do_monitor(int argc, char **argv);
+int do_mst(int argc, char **argv);
 int do_vlan(int argc, char **argv);
 int do_link(int argc, char **argv);
 int do_vni(int argc, char **argv);

diff --git a/bridge/bridge.c b/bridge/bridge.c
index ef592815..f8b5646a 100644
--- a/bridge/bridge.c
+++ b/bridge/bridge.c

@@ -36,7 +36,7 @@ static void usage(void)
 	fprintf(stderr,
 "Usage: bridge [ OPTIONS ] OBJECT { COMMAND | help }\n"
 "       bridge [ -force ] -batch filename\n"
-"where  OBJECT := { link | fdb | mdb | vlan | vni | monitor }\n"
+"where  OBJECT := { link | fdb | mdb | mst | vlan | vni | monitor }\n"
 "       OPTIONS := { -V[ersion] | -s[tatistics] | -d[etails] |\n"
 "                    -o[neline] | -t[imestamp] | -n[etns] name |\n"
 "                    -com[pressvlans] -c[olor] -p[retty] -j[son] }\n");

@@ -56,6 +56,7 @@ static const struct cmd {
 	{ "link",	do_link },
 	{ "fdb",	do_fdb },
 	{ "mdb",	do_mdb },
+	{ "mst",	do_mst },
 	{ "vlan",	do_vlan },
 	{ "vni",	do_vni },
 	{ "monitor",	do_monitor },

diff --git a/bridge/mst.c b/bridge/mst.c
new file mode 100644
index 00000000..873ca536
--- /dev/null
+++ b/bridge/mst.c

@@ -0,0 +1,262 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Get/set Multiple Spanning Tree (MST) states
+ */
+
+#include <stdio.h>
+#include <linux/if_bridge.h>
+#include <net/if.h>
+
+#include "libnetlink.h"
+#include "json_print.h"
+#include "utils.h"
+
+#include "br_common.h"
+
+#define MST_ID_LEN 9
+
+#define __stringify_1(x...) #x
+#define __stringify(x...) __stringify_1(x)

+		switch (rta_type) {
+		case IFLA_BRIDGE_MST_ENTRY:
+			if (!opened) {
+				open_json_object(NULL);
+				print_color_string(PRINT_ANY, COLOR_IFNAME,
+						   "ifname",
+						   "%-" __stringify(IFNAMSIZ) "s  ",
+						   ll_index_to_name(ifi->ifi_index));
+				open_json_array(PRINT_JSON, "mst");
+				opened = true;
+			} else {
+				print_string(PRINT_FP, NULL, "%-"
+					     __stringify(IFNAMSIZ) "s  ", "");
+			}
+
+			print_mst_entry(a, arg);
+			break;
+		}
+	}
+
+	if (opened) {
+		close_json_array(PRINT_JSON, NULL);
+		close_json_object();
+	}
+
+	return 0;
+}
+
+static int mst_show(int argc, char **argv)
+{
+	char *filter_dev = NULL;
+
+	while (argc > 0) {
+		if (strcmp(*argv, "dev") == 0) {
+			NEXT_ARG();
+			if (filter_dev)
+				duparg("dev", *argv);
+			filter_dev = *argv;
+		}
+		argc--; argv++;
+	}
+
+	if (filter_dev) {
+		filter_index = ll_name_to_index(filter_dev);
+		if (!filter_index)
+			return nodev(filter_dev);
+	}
+
+	if (rtnl_linkdump_req_filter(&rth, PF_BRIDGE, RTEXT_FILTER_MST) < 0) {
+		perror("Cannon send dump request");
+		exit(1);
+	}
+
+	new_json_obj(json);
+
+	if (!is_json_context()) {
+		printf("%-" __stringify(IFNAMSIZ) "s  "
+		       "%-" __stringify(MST_ID_LEN) "s",
+		       "port", "msti");
+		printf("\n");
+	}
+
+	if (rtnl_dump_filter(&rth, print_msts, stdout) < 0) {
+		fprintf(stderr, "Dump terminated\n");
+		return -1;
+	}
+
+	delete_json_obj();
+	fflush(stdout);
+	return 0;
+}
+
+static int mst_set(int argc, char **argv)
+{
+	struct {
+		struct nlmsghdr		n;
+		struct ifinfomsg	ifi;
+		char			buf[512];
+	} req = {
+		.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg)),
+		.n.nlmsg_flags = NLM_F_REQUEST,
+		.n.nlmsg_type = RTM_SETLINK,
+		.ifi.ifi_family = PF_BRIDGE,
+	};
+	char *d = NULL, *m = NULL, *s = NULL, *endptr;
+	struct rtattr *af_spec, *mst, *entry;
+	__u16 msti;
+	__u8 state;
+
+	while (argc > 0) {
+		if (strcmp(*argv, "dev") == 0) {
+			NEXT_ARG();
+			d = *argv;
+		} else if (strcmp(*argv, "msti") == 0) {
+			NEXT_ARG();
+			m = *argv;
+		} else if (strcmp(*argv, "state") == 0) {
+			NEXT_ARG();
+			s = *argv;
+		} else {
+			if (matches(*argv, "help") == 0)
+				usage();
+		}
+		argc--; argv++;
+	}
+
+	if (d == NULL || m == NULL || s == NULL) {
+		fprintf(stderr, "Device, MSTI and state are required arguments.\n");
+		return -1;
+	}
+
+	req.ifi.ifi_index = ll_name_to_index(d);
+	if (!req.ifi.ifi_index)
+		return nodev(d);
+
+	msti = strtol(m, &endptr, 10);
+	if (!(*s != '\0' && *endptr == '\0')) {
+		fprintf(stderr,
+			"Error: invalid MSTI\n");
+		return -1;
+	}
+
+	state = strtol(s, &endptr, 10);
+	if (!(*s != '\0' && *endptr == '\0')) {
+		state = parse_stp_state(s);
+		if (state == -1) {
+			fprintf(stderr,
+				"Error: invalid STP port state\n");
+			return -1;
+		}
+	}
+
+	af_spec = addattr_nest(&req.n, sizeof(req), IFLA_AF_SPEC);
+	mst = addattr_nest(&req.n, sizeof(req), IFLA_BRIDGE_MST);
+
+	entry = addattr_nest(&req.n, sizeof(req), IFLA_BRIDGE_MST_ENTRY);
+	entry->rta_type |= NLA_F_NESTED;
+
+	addattr16(&req.n, sizeof(req), IFLA_BRIDGE_MST_ENTRY_MSTI, msti);
+	addattr8(&req.n, sizeof(req), IFLA_BRIDGE_MST_ENTRY_STATE, state);
+
+	addattr_nest_end(&req.n, entry);
+
+	addattr_nest_end(&req.n, mst);
+	addattr_nest_end(&req.n, af_spec);
+
+
+	if (rtnl_talk(&rth, &req.n, NULL) < 0)
+		return -1;
+
+	return 0;
+}
+
+int do_mst(int argc, char **argv)
+{
+	ll_init_map(&rth);
+
+	if (argc > 0) {
+		if (matches(*argv, "set") == 0)
+			return mst_set(argc-1, argv+1);
+
+		if (matches(*argv, "show") == 0 ||
+		    matches(*argv, "lst") == 0 ||
+		    matches(*argv, "list") == 0)
+			return mst_show(argc-1, argv+1);
+		if (matches(*argv, "help") == 0)
+			usage();
+	} else
+		return mst_show(0, NULL);
+
+	fprintf(stderr, "Command \"%s\" is unknown, try \"bridge mst help\".\n", *argv);
+	exit(-1);
+}

diff --git a/man/man8/bridge.8 b/man/man8/bridge.8
index b4699801..08f329c6 100644
--- a/man/man8/bridge.8
+++ b/man/man8/bridge.8

@@ -207,6 +207,15 @@ bridge \- show / manipulate bridge addresses and devices
 .RB "[ " vni
 .IR VNI " ]"
 
+.ti -8
+.B "bridge mst set"
+.IR dev " DEV " msti " MSTI " state " STP_STATE "
+
+.ti -8
+.BR "bridge mst" " [ [ " show " ] [ "
+.B dev
+.IR DEV " ] ]"
+
 .ti -8
 .BR "bridge vlan" " { " add " | " del " } "
 .B dev

@@ -1247,6 +1256,54 @@ endpoint. Match entries only with the specified destination port number.
 the VXLAN VNI Network Identifier to use to connect to the remote VXLAN tunnel
 endpoint. Match entries only with the specified destination VNI.
 
+.SH bridge mst - multiple spanning tree port states
+
+In the multiple spanning tree (MST) model, the active paths through a
+network can be different for different VLANs.  In other words, a
+bridge port can simultaneously forward one subset of VLANs, while
+blocking another.
+
+Provided that the
+.B mst_enable
+bridge option is enabled, a group of VLANs can be forwarded along the
+same spanning tree by associating them with the same instance (MSTI)
+using
+.BR "bridge vlan global set" .