Add network link + address monitiring via osysmon_rtnl.c
diff --git a/osysmon_rtnl.c b/osysmon_rtnl.c
new file mode 100644
index 0000000..94d8bf9
--- /dev/null
+++ b/osysmon_rtnl.c
@@ -0,0 +1,416 @@
+/* Simple Osmocom System Monitor (osysmon): Support for monitoring net-devices */
+
+/* (C) 2018 by Harald Welte <laforge@gnumonks.org>
+ * All Rights Reserved.
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ *
+ * This program 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 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301, USA.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <time.h>
+#include <arpa/inet.h>
+
+#include <linux/if.h>
+#include <linux/if_link.h>
+#include <linux/rtnetlink.h>
+
+#include <libmnl/libmnl.h>
+#include <talloc.h>
+
+#include "value_node.h"
+#include "osysmon.h"
+
+struct rtnl_client_state {
+ struct mnl_socket *nl;
+};
+
+
+struct netdev {
+ struct llist_head list;
+ struct {
+ const char *name;
+ } cfg;
+};
+
+static struct netdev *netdev_find(struct osysmon_state *os, const char *name)
+{
+ struct netdev *nd;
+ llist_for_each_entry(nd, &os->netdevs, list) {
+ if (!strcmp(name, nd->cfg.name))
+ return nd;
+ }
+ return NULL;
+}
+
+static struct netdev *netdev_create(struct osysmon_state *os, const char *name)
+{
+ struct netdev *nd;
+
+ if (netdev_find(os, name))
+ return NULL;
+
+ nd = talloc_zero(os, struct netdev);
+ if (!nd)
+ return NULL;
+ nd->cfg.name = talloc_strdup(os, name);
+ llist_add_tail(&nd->list, &os->netdevs);
+ return nd;
+}
+
+static void netdev_destroy(struct netdev *nd)
+{
+ llist_del(&nd->list);
+ talloc_free(nd);
+}
+
+/***********************************************************************
+ * VTY
+ ***********************************************************************/
+
+static struct cmd_node netdev_node = {
+ NETDEV_NODE,
+ "%s(config-netdev)# ",
+ 1,
+};
+
+int osysmon_netdev_go_parent(struct vty *vty)
+{
+ switch (vty->node) {
+ case NETDEV_NODE:
+ vty->node = CONFIG_NODE;
+ vty->index = NULL;
+ break;
+ default:
+ break;
+ }
+ return vty->node;
+}
+
+DEFUN(cfg_netdev, cfg_netdev_cmd,
+ "netdev NAME",
+ "")
+{
+ struct netdev *nd;
+ nd = netdev_find(g_oss, argv[0]);
+ if (!nd)
+ nd = netdev_create(g_oss, argv[0]);
+ OSMO_ASSERT(nd);
+
+ return CMD_SUCCESS;
+}
+
+DEFUN(cfg_no_netdev, cfg_no_netdev_cmd,
+ "no netdev NAME",
+ "")
+{
+ struct netdev *nd;
+ nd = netdev_find(g_oss, argv[0]);
+ if (!nd) {
+ vty_out(vty, "Netdev %s doesn't exist in configuration%s", argv[0], VTY_NEWLINE);
+ return CMD_WARNING;
+ }
+ netdev_destroy(nd);
+ return CMD_SUCCESS;
+}
+
+static void write_one_netdev(struct vty *vty, struct netdev *nd)
+{
+ vty_out(vty, "netdev %s%s", nd->cfg.name, VTY_NEWLINE);
+}
+
+static int config_write_netdev(struct vty *vty)
+{
+ struct netdev *nd;
+
+ llist_for_each_entry(nd, &g_oss->netdevs, list)
+ write_one_netdev(vty, nd);
+ return CMD_SUCCESS;
+}
+
+static void osysmon_rtnl_vty_init(void)
+{
+ install_element(CONFIG_NODE, &cfg_netdev_cmd);
+ install_element(CONFIG_NODE, &cfg_no_netdev_cmd);
+ install_node(&netdev_node, config_write_netdev);
+}
+
+
+/***********************************************************************
+ * Interface Level
+ ***********************************************************************/
+
+static int if_attr_cb(const struct nlattr *attr, void *data)
+{
+ const struct nlattr **tb = data;
+ int type = mnl_attr_get_type(attr);
+
+ /* skip unsupported attribute in user-space */
+ if (mnl_attr_type_valid(attr, IFLA_MAX) < 0)
+ return MNL_CB_OK;
+
+ switch(type) {
+ case IFLA_ADDRESS:
+ if (mnl_attr_validate(attr, MNL_TYPE_BINARY) < 0) {
+ perror("mnl_attr_validate");
+ return MNL_CB_ERROR;
+ }
+ break;
+ case IFLA_MTU:
+ if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0) {
+ perror("mnl_attr_validate");
+ return MNL_CB_ERROR;
+ }
+ break;
+ case IFLA_IFNAME:
+ if (mnl_attr_validate(attr, MNL_TYPE_STRING) < 0) {
+ perror("mnl_attr_validate");
+ return MNL_CB_ERROR;
+ }
+ break;
+ }
+ tb[type] = attr;
+ return MNL_CB_OK;
+}
+
+static int data_cb(const struct nlmsghdr *nlh, void *data)
+{
+ struct ifinfomsg *ifm = mnl_nlmsg_get_payload(nlh);
+ struct value_node *parent = data;
+ struct value_node *vn_if;
+ const char *name;
+ char buf[32];
+
+ struct nlattr *tb[IFLA_MAX+1] = {};
+ mnl_attr_parse(nlh, sizeof(*ifm), if_attr_cb, tb);
+ if (!tb[IFLA_IFNAME])
+ return MNL_CB_OK;
+ name = mnl_attr_get_str(tb[IFLA_IFNAME]);
+
+ /* skip any non-configured interface names */
+ if (!netdev_find(g_oss, name))
+ return MNL_CB_OK;
+
+ vn_if = value_node_find_or_add(parent, talloc_strdup(parent, name));
+ OSMO_ASSERT(vn_if);
+ vn_if->idx = ifm->ifi_index;
+
+ if (tb[IFLA_ADDRESS] && mnl_attr_get_payload_len(tb[IFLA_ADDRESS]) == 6) {
+ uint8_t *hwaddr = mnl_attr_get_payload(tb[IFLA_ADDRESS]);
+ snprintf(buf, sizeof(buf), "%02x:%02x:%02x:%02x:%02x:%02x",
+ hwaddr[0], hwaddr[1], hwaddr[2], hwaddr[3], hwaddr[4], hwaddr[5]);
+ value_node_add(vn_if, vn_if, "hwaddr", buf);
+ }
+ if (ifm->ifi_flags & IFF_RUNNING)
+ value_node_add(vn_if, vn_if, "running", "true");
+ else
+ value_node_add(vn_if, vn_if, "running", "false");
+
+ if (ifm->ifi_flags & IFF_UP)
+ value_node_add(vn_if, vn_if, "up", "true");
+ else
+ value_node_add(vn_if, vn_if, "up", "false");
+
+ return MNL_CB_OK;
+}
+
+static int rtnl_update_link(struct rtnl_client_state *rcs, struct value_node *parent)
+{
+ char buf[MNL_SOCKET_BUFFER_SIZE];
+ struct nlmsghdr *nlh;
+ struct rtgenmsg *rt;
+ int ret;
+ unsigned int seq, portid;
+
+ nlh = mnl_nlmsg_put_header(buf);
+ nlh->nlmsg_type = RTM_GETLINK;
+ nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP;
+ nlh->nlmsg_seq = seq = time(NULL);
+ rt = mnl_nlmsg_put_extra_header(nlh, sizeof(struct rtgenmsg));
+ rt->rtgen_family = AF_PACKET;
+
+ portid = mnl_socket_get_portid(rcs->nl);
+
+ if (mnl_socket_sendto(rcs->nl, nlh, nlh->nlmsg_len) < 0) {
+ perror("mnl_socket_sendto");
+ exit(EXIT_FAILURE);
+ }
+
+ ret = mnl_socket_recvfrom(rcs->nl, buf, sizeof(buf));
+ while (ret > 0) {
+ ret = mnl_cb_run(buf, ret, seq, portid, data_cb, parent);
+ if (ret <= MNL_CB_STOP)
+ break;
+ ret = mnl_socket_recvfrom(rcs->nl, buf, sizeof(buf));
+ }
+ if (ret == -1) {
+ perror("error");
+ return -1;
+ }
+ return 0;
+}
+
+
+
+/***********************************************************************
+ * L3 Address Level
+ ***********************************************************************/
+
+static int inet_attr_cb(const struct nlattr *attr, void *data)
+{
+ const struct nlattr **tb = data;
+ int type = mnl_attr_get_type(attr);
+
+ /* skip unsupported attribute in user-space */
+ if (mnl_attr_type_valid(attr, IFA_MAX) < 0)
+ return MNL_CB_OK;
+
+ switch(type) {
+ case IFA_ADDRESS:
+ if (mnl_attr_validate(attr, MNL_TYPE_BINARY) < 0) {
+ perror("mnl_attr_validate");
+ return MNL_CB_ERROR;
+ }
+ break;
+ }
+ tb[type] = attr;
+ return MNL_CB_OK;
+}
+
+static int inet_data_cb(const struct nlmsghdr *nlh, void *data)
+{
+ struct ifaddrmsg *ifa = mnl_nlmsg_get_payload(nlh);
+ struct nlattr *tb[IFA_MAX + 1] = {};
+ struct value_node *parent = data;
+ struct value_node *vn_if;
+
+ vn_if = value_node_find_by_idx(parent, ifa->ifa_index);
+ if (!vn_if)
+ return MNL_CB_OK;
+
+ if (ifa->ifa_family != AF_INET)
+ return MNL_CB_OK;
+
+ mnl_attr_parse(nlh, sizeof(*ifa), inet_attr_cb, tb);
+ if (tb[IFA_ADDRESS]) {
+ struct in_addr *addr = mnl_attr_get_payload(tb[IFA_ADDRESS]);
+ char out[INET_ADDRSTRLEN+32];
+ snprintf(out, sizeof(out), "%s/%u", inet_ntoa(*addr), ifa->ifa_prefixlen);
+ value_node_add(vn_if, vn_if, "ip", out);
+ }
+
+ return MNL_CB_OK;
+}
+
+static int rtnl_update_addr(struct rtnl_client_state *rcs, struct value_node *parent)
+{
+ char buf[MNL_SOCKET_BUFFER_SIZE];
+ struct nlmsghdr *nlh;
+ struct rtgenmsg *rt;
+ int ret;
+ unsigned int seq, portid;
+
+ nlh = mnl_nlmsg_put_header(buf);
+ nlh->nlmsg_type = RTM_GETADDR;
+ nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP;
+ nlh->nlmsg_seq = seq = time(NULL);
+ rt = mnl_nlmsg_put_extra_header(nlh, sizeof(struct rtgenmsg));
+ rt->rtgen_family = AF_INET;
+
+ portid = mnl_socket_get_portid(rcs->nl);
+
+ if (mnl_socket_sendto(rcs->nl, nlh, nlh->nlmsg_len) < 0) {
+ perror("mnl_socket_sendto");
+ exit(EXIT_FAILURE);
+ }
+
+ ret = mnl_socket_recvfrom(rcs->nl, buf, sizeof(buf));
+ while (ret > 0) {
+ ret = mnl_cb_run(buf, ret, seq, portid, inet_data_cb, parent);
+ if (ret <= MNL_CB_STOP)
+ break;
+ ret = mnl_socket_recvfrom(rcs->nl, buf, sizeof(buf));
+ }
+ if (ret == -1) {
+ perror("error");
+ return -1;
+ }
+
+ return 0;
+}
+
+
+
+/***********************************************************************
+ * Common Code / API
+ ***********************************************************************/
+
+int osysmon_rtnl_init()
+{
+ osysmon_rtnl_vty_init();
+ return 0;
+}
+
+
+
+struct rtnl_client_state *rtnl_init(void *ctx)
+{
+ struct mnl_socket *nl;
+ struct rtnl_client_state *rcs;
+
+ nl = mnl_socket_open(NETLINK_ROUTE);
+ if (nl == NULL) {
+ perror("mnl_socket_open");
+ return NULL;
+ }
+ if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0) {
+ perror("mnl_socket_bind");
+ mnl_socket_close(nl);
+ return NULL;
+ }
+
+ rcs = talloc_zero(ctx, struct rtnl_client_state);
+ if (!rcs) {
+ mnl_socket_close(nl);
+ return NULL;
+ }
+
+ rcs->nl = nl;
+
+ return rcs;
+}
+
+int osysmon_rtnl_poll(struct value_node *parent)
+{
+ struct value_node *vn_net;
+
+ if (!g_oss->rcs)
+ g_oss->rcs = rtnl_init(NULL);
+
+ vn_net = value_node_add(parent, parent, "netdev", NULL);
+
+ if (!g_oss->rcs)
+ return -1;
+
+ rtnl_update_link(g_oss->rcs, vn_net);
+ rtnl_update_addr(g_oss->rcs, vn_net);
+
+ return 0;
+}