1 /* 2 * Copyright (C) 2019 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package android.net.util; 18 19 import android.annotation.IntDef; 20 21 import java.lang.annotation.Retention; 22 import java.lang.annotation.RetentionPolicy; 23 24 /** 25 * Collection of utilities for data stall. 26 */ 27 public class DataStallUtils { 28 public static final int DATA_STALL_EVALUATION_TYPE_NONE = 0; 29 /** Detect data stall using dns timeout counts. */ 30 public static final int DATA_STALL_EVALUATION_TYPE_DNS = 1 << 0; 31 /** Detect data stall using tcp connection fail rate. */ 32 public static final int DATA_STALL_EVALUATION_TYPE_TCP = 1 << 1; 33 34 @IntDef(prefix = { "DATA_STALL_EVALUATION_TYPE_" }, value = { 35 DATA_STALL_EVALUATION_TYPE_NONE, 36 DATA_STALL_EVALUATION_TYPE_DNS, 37 DATA_STALL_EVALUATION_TYPE_TCP, 38 }) 39 @Retention(RetentionPolicy.SOURCE) 40 public @interface EvaluationType { 41 } 42 43 // Default configuration values for data stall detection. 44 public static final int DEFAULT_CONSECUTIVE_DNS_TIMEOUT_THRESHOLD = 5; 45 public static final int DEFAULT_DATA_STALL_MIN_EVALUATE_TIME_MS = 60 * 1000; 46 public static final int DEFAULT_DATA_STALL_VALID_DNS_TIME_THRESHOLD_MS = 30 * 60 * 1000; 47 /** 48 * The threshold value for the number of consecutive dns timeout events received to be a 49 * signal of data stall. The number of consecutive timeouts needs to be {@code >=} this 50 * threshold to be considered a data stall. Set the value to {@code <= 0} to disable. Note 51 * that the value should be {@code > 0} if the DNS data stall detection is enabled. 52 * 53 */ 54 public static final String CONFIG_DATA_STALL_CONSECUTIVE_DNS_TIMEOUT_THRESHOLD = 55 "data_stall_consecutive_dns_timeout_threshold"; 56 57 /** 58 * The minimal time interval in milliseconds for data stall reevaluation. 59 * 60 */ 61 public static final String CONFIG_DATA_STALL_MIN_EVALUATE_INTERVAL = 62 "data_stall_min_evaluate_interval"; 63 64 /** 65 * DNS timeouts older than this timeout (in milliseconds) are not considered for detecting 66 * a data stall. 67 * 68 */ 69 public static final String CONFIG_DATA_STALL_VALID_DNS_TIME_THRESHOLD = 70 "data_stall_valid_dns_time_threshold"; 71 72 /** 73 * Which data stall detection signal to use. This is a bitmask constructed by bitwise-or-ing 74 * (i.e. {@code |}) the DATA_STALL_EVALUATION_TYPE_* values. 75 * 76 * Type: int 77 * Valid values: 78 * {@link #DATA_STALL_EVALUATION_TYPE_DNS} : Use dns as a signal. 79 * {@link #DATA_STALL_EVALUATION_TYPE_TCP} : Use tcp info as a signal. 80 */ 81 public static final String CONFIG_DATA_STALL_EVALUATION_TYPE = "data_stall_evaluation_type"; 82 public static final int DEFAULT_DATA_STALL_EVALUATION_TYPES = 83 DATA_STALL_EVALUATION_TYPE_DNS | DATA_STALL_EVALUATION_TYPE_TCP; 84 // The default number of DNS events kept of the log kept for dns signal evaluation. Each event 85 // is represented by a {@link com.android.server.connectivity.NetworkMonitor#DnsResult} objects. 86 // It's also the size of array of {@link com.android.server.connectivity.nano.DnsEvent} kept in 87 // metrics. Note that increasing the size may cause statsd log buffer bust. Need to check the 88 // design in statsd when you try to increase the size. 89 public static final int DEFAULT_DNS_LOG_SIZE = 20; 90 91 /** 92 * The time interval for polling tcp info to observe the tcp health. 93 */ 94 public static String CONFIG_DATA_STALL_TCP_POLLING_INTERVAL = "data_stall_tcp_polling_interval"; 95 96 /** 97 * Default polling interval to observe the tcp health. 98 */ 99 public static int DEFAULT_TCP_POLLING_INTERVAL_MS = 20_000; 100 101 /** 102 * Default tcp packets fail rate to suspect as a data stall. 103 * 104 * Calculated by ((# of packets lost)+(# of packets retrans))/(# of packets sent)*100. Ideally, 105 * the percentage should be 100%. However, the ongoing packets may not be considered as neither 106 * lost or retrans yet. It will cause the percentage lower. 107 */ 108 public static final int DEFAULT_TCP_PACKETS_FAIL_PERCENTAGE = 80; 109 110 /** 111 * The percentage of tcp packets fail rate to be suspected as a data stall. 112 * 113 * Type: int 114 * Valid values: 0 to 100. 115 */ 116 public static final String CONFIG_TCP_PACKETS_FAIL_PERCENTAGE = "tcp_packets_fail_percentage"; 117 118 /** Corresponds to enum from bionic/libc/include/netinet/tcp.h. */ 119 public static final int TCP_ESTABLISHED = 1; 120 public static final int TCP_SYN_SENT = 2; 121 public static final int TCP_SYN_RECV = 3; 122 public static final int TCP_MONITOR_STATE_FILTER = 123 (1 << TCP_ESTABLISHED) | (1 << TCP_SYN_SENT) | (1 << TCP_SYN_RECV); 124 125 /** 126 * Threshold for the minimal tcp packets count to evaluate data stall via tcp info. 127 */ 128 public static final int DEFAULT_DATA_STALL_MIN_PACKETS_THRESHOLD = 10; 129 public static final String CONFIG_MIN_PACKETS_THRESHOLD = "tcp_min_packets_threshold"; 130 } 131