| /* Simple Osmocom System Monitor (osysmon): Support for OpenVPN monitoring */ |
| |
| /* (C) 2019 by sysmocom - s.f.m.c. GmbH. |
| * Author: Max Suraev |
| * 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. |
| */ |
| |
| #include <string.h> |
| #include <stdbool.h> |
| #include <ctype.h> |
| #include <errno.h> |
| |
| #include <osmocom/core/utils.h> |
| #include <osmocom/vty/vty.h> |
| #include <osmocom/vty/command.h> |
| #include <osmocom/core/msgb.h> |
| #include <osmocom/netif/stream.h> |
| |
| #include "osysmon.h" |
| #include "client.h" |
| #include "value_node.h" |
| |
| /*********************************************************************** |
| * Data model |
| ***********************************************************************/ |
| |
| #define OVPN_LOG(ctx, vpn, fmt, args...) \ |
| fprintf(stderr, "OpenVPN [%s]: " fmt, make_authority(ctx, vpn->cfg), ##args) |
| |
| /* max number of csv in response */ |
| #define MAX_RESP_COMPONENTS 6 |
| |
| /* a single OpenVPN management interface client */ |
| struct openvpn_client { |
| /* links to osysmon.openvpn_clients */ |
| struct llist_head list; |
| struct host_cfg *cfg; |
| struct osmo_stream_cli *mgmt; |
| /* fields below are parsed from response to 'state' command on mgmt interface */ |
| struct host_cfg *rem_cfg; |
| char *tun_ip; |
| bool connected; |
| }; |
| |
| /* |
| * The string format is documented in https://openvpn.net/community-resources/management-interface/ |
| * Conversation loop looks like this (non-null terminated strings): |
| * CLI -> SRV: "state" |
| * SRV -> CLI: "1552674378,CONNECTED,SUCCESS,10.8.0.11,144.76.43.77,1194,," {0x0d, 0xa} "END" {0x0d, 0xa} |
| * More or less comma-separated fields are returned depending on OpenVPN version. |
| * v2.1.3: Sends only up to field 4 incl, eg: "1552674378,CONNECTED,SUCCESS,10.8.0.11,144.76.43.77" {0x0d, 0xa} "END" {0x0d, 0xa} |
| */ |
| static char *parse_state(struct msgb *msg, struct openvpn_client *vpn) |
| { |
| char tmp[128], buf[128]; |
| char *tok; |
| unsigned int i; |
| uint8_t *m = msgb_data(msg); |
| unsigned int truncated_len = OSMO_MIN(sizeof(tmp) - 1, msgb_length(msg)); |
| |
| if (msgb_length(msg) > truncated_len) |
| OVPN_LOG(msg, vpn, "received message too long (%d >= %u), truncating...\n", msgb_length(msg), truncated_len); |
| |
| if (msgb_length(msg) > 0) { |
| if (!isdigit(m[0])) /* skip OpenVPN greetings and alike */ |
| return NULL; |
| } else { |
| OVPN_LOG(msg, vpn, "received message is empty, ignoring...\n"); |
| return NULL; |
| } |
| |
| memcpy(tmp, m, truncated_len); |
| tmp[truncated_len] = '\0'; |
| |
| /* Only interested in first line; Remove return carriage, line feed + new line string "END" */ |
| for (i = 0; i < truncated_len; i++) { |
| if (!isprint(tmp[i])) { |
| tmp[i] = '\0'; |
| break; |
| } |
| } |
| |
| for (tok = strtok(tmp, ","), i = 0; tok && i < MAX_RESP_COMPONENTS; tok = strtok(NULL, ",")) { |
| /* Parse csv string and pick interesting tokens while ignoring the rest. */ |
| switch (i++) { |
| /* case 0: unix/date time, not needed */ |
| case 1: |
| update_name(vpn->rem_cfg, tok); |
| break; |
| case 2: |
| snprintf(buf, sizeof(buf), "%s (%s)", vpn->rem_cfg->name, tok); |
| update_name(vpn->rem_cfg, buf); |
| break; |
| case 3: |
| osmo_talloc_replace_string(vpn->rem_cfg, &vpn->tun_ip, tok); |
| break; |
| case 4: |
| update_host(vpn->rem_cfg, tok); |
| break; |
| case 5: |
| vpn->rem_cfg->remote_port = atoi(tok); |
| break; |
| } |
| } |
| return NULL; |
| } |
| |
| static struct openvpn_client *openvpn_client_find_or_make(const struct osysmon_state *os, |
| const char *host, uint16_t port) |
| { |
| struct openvpn_client *vpn; |
| llist_for_each_entry(vpn, &os->openvpn_clients, list) { |
| if (match_config(vpn->cfg, host, MATCH_HOST) && vpn->cfg->remote_port == port) |
| return vpn; |
| } |
| |
| return NULL; |
| } |
| |
| static int disconnect_cb(struct osmo_stream_cli *conn) |
| { |
| struct openvpn_client *vpn = osmo_stream_cli_get_data(conn); |
| |
| update_name(vpn->rem_cfg, "disconnected from openvpn management socket"); |
| vpn->connected = false; |
| talloc_free(vpn->tun_ip); |
| talloc_free(vpn->rem_cfg->remote_host); |
| vpn->tun_ip = NULL; |
| vpn->rem_cfg->remote_host = NULL; |
| |
| return 0; |
| } |
| |
| static int connect_cb(struct osmo_stream_cli *conn) |
| { |
| struct openvpn_client *vpn = osmo_stream_cli_get_data(conn); |
| |
| update_name(vpn->rem_cfg, "connected to openvpn management socket"); |
| vpn->connected = true; |
| |
| return 0; |
| } |
| |
| static int read_cb(struct osmo_stream_cli *conn) |
| { |
| int bytes; |
| struct openvpn_client *vpn = osmo_stream_cli_get_data(conn); |
| struct msgb *msg = msgb_alloc(1024, "OpenVPN"); |
| if (!msg) { |
| OVPN_LOG(conn, vpn, "unable to allocate message in callback\n"); |
| return 0; |
| } |
| |
| bytes = osmo_stream_cli_recv(conn, msg); |
| if (bytes < 0) |
| OVPN_LOG(msg, vpn, "read on openvpn management socket failed (%d)\n", bytes); |
| else |
| parse_state(msg, vpn); |
| |
| msgb_free(msg); |
| |
| return 0; |
| } |
| |
| static bool openvpn_client_create(struct osysmon_state *os, const char *name, const char *host, uint16_t port) |
| { |
| struct openvpn_client *vpn = openvpn_client_find_or_make(os, host, port); |
| if (vpn) |
| return true; |
| |
| vpn = talloc_zero(os, struct openvpn_client); |
| if (!vpn) |
| return false; |
| |
| vpn->connected = false; |
| |
| vpn->cfg = host_cfg_alloc(vpn, name, host, port); |
| if (!vpn->cfg) |
| goto dealloc; |
| |
| vpn->rem_cfg = host_cfg_alloc(vpn, "connecting to openvpn management socket", NULL, 0); |
| if (!vpn->rem_cfg) |
| goto dealloc; |
| |
| vpn->mgmt = make_tcp_client(vpn->cfg); |
| if (!vpn->mgmt) { |
| OVPN_LOG(vpn->rem_cfg, vpn, "failed to create TCP client\n"); |
| goto dealloc; |
| } |
| |
| /* Wait for 1 minute before attempting to reconnect to management interface */ |
| osmo_stream_cli_set_reconnect_timeout(vpn->mgmt, 5); |
| osmo_stream_cli_set_read_cb(vpn->mgmt, read_cb); |
| osmo_stream_cli_set_connect_cb(vpn->mgmt, connect_cb); |
| osmo_stream_cli_set_disconnect_cb(vpn->mgmt, disconnect_cb); |
| |
| if (osmo_stream_cli_open(vpn->mgmt) < 0) { |
| OVPN_LOG(vpn->rem_cfg, vpn, "failed to connect to management socket\n"); |
| goto dealloc; |
| } |
| |
| osmo_stream_cli_set_data(vpn->mgmt, vpn); |
| llist_add_tail(&vpn->list, &os->openvpn_clients); |
| |
| return true; |
| |
| dealloc: |
| talloc_free(vpn); |
| return false; |
| } |
| |
| static void openvpn_client_destroy(struct openvpn_client *vpn) |
| { |
| if (!vpn) |
| return; |
| |
| osmo_stream_cli_destroy(vpn->mgmt); |
| llist_del(&vpn->list); |
| talloc_free(vpn); |
| } |
| |
| |
| /*********************************************************************** |
| * VTY |
| ***********************************************************************/ |
| |
| #define OPENVPN_STR "Configure OpenVPN management interface address\n" |
| |
| DEFUN(cfg_openvpn, cfg_openvpn_cmd, |
| "openvpn HOST <1-65535>", |
| OPENVPN_STR "Name of the host to connect to\n" "Management interface port\n") |
| { |
| uint16_t port = atoi(argv[1]); |
| |
| if (!openvpn_client_create(g_oss, "OpenVPN", argv[0], port)) { |
| vty_out(vty, "Failed to create OpenVPN client for %s:%u%s", argv[0], port, VTY_NEWLINE); |
| return CMD_WARNING; |
| } |
| |
| return CMD_SUCCESS; |
| } |
| |
| DEFUN(cfg_no_openvpn, cfg_no_openvpn_cmd, |
| "no openvpn HOST <1-65535>", |
| NO_STR OPENVPN_STR "Name of the host to connect to\n" "Management interface port\n") |
| { |
| uint16_t port = atoi(argv[1]); |
| struct openvpn_client *vpn = openvpn_client_find_or_make(g_oss, argv[0], port); |
| if (!vpn) { |
| vty_out(vty, "OpenVPN client %s:%u doesn't exist%s", argv[0], port, VTY_NEWLINE); |
| return CMD_WARNING; |
| } |
| |
| openvpn_client_destroy(vpn); |
| |
| return CMD_SUCCESS; |
| } |
| |
| |
| /*********************************************************************** |
| * Runtime Code |
| ***********************************************************************/ |
| |
| static int openvpn_client_poll(struct openvpn_client *vpn, struct value_node *parent) |
| { |
| char *remote = make_authority(parent, vpn->rem_cfg); |
| struct value_node *vn_host = value_node_find_or_add(parent, make_authority(parent, vpn->cfg)); |
| struct msgb *msg = msgb_alloc(128, "state"); |
| if (!msg) { |
| value_node_add(vn_host, "msgb", "memory allocation failure"); |
| return 0; |
| } |
| |
| if (vpn->rem_cfg->name) |
| value_node_add(vn_host, "status", vpn->rem_cfg->name); |
| |
| if (vpn->tun_ip) |
| value_node_add(vn_host, "tunnel", vpn->tun_ip); |
| |
| if (remote) |
| value_node_add(vn_host, "remote", remote); |
| |
| if (vpn->connected) { /* re-trigger state command */ |
| msgb_printf(msg, "state\n"); |
| osmo_stream_cli_send(vpn->mgmt, msg); |
| } |
| |
| return 0; |
| } |
| |
| /* called once on startup before config file parsing */ |
| int osysmon_openvpn_init() |
| { |
| install_element(CONFIG_NODE, &cfg_openvpn_cmd); |
| install_element(CONFIG_NODE, &cfg_no_openvpn_cmd); |
| |
| return 0; |
| } |
| |
| /* called periodically */ |
| int osysmon_openvpn_poll(struct value_node *parent) |
| { |
| int num_vpns = llist_count(&g_oss->openvpn_clients); |
| if (num_vpns) { |
| struct value_node *vn_vpn = value_node_add(parent, "OpenVPN", NULL); |
| struct openvpn_client *vpn; |
| llist_for_each_entry(vpn, &g_oss->openvpn_clients, list) |
| openvpn_client_poll(vpn, vn_vpn); |
| } |
| |
| return num_vpns; |
| } |