1 /*
2  * Copyright (C) 2022 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 com.android.net.module.util;
18 
19 import java.io.IOException;
20 
21 /**
22  * Contains mostly tc-related functionality.
23  */
24 public class TcUtils {
25     static {
JniUtil.getJniLibraryName()26         System.loadLibrary(JniUtil.getJniLibraryName(TcUtils.class.getPackage()));
27     }
28 
29     /**
30      * Checks if the network interface uses an ethernet L2 header.
31      *
32      * @param iface the network interface.
33      * @return true if the interface uses an ethernet L2 header.
34      * @throws IOException
35      */
isEthernet(String iface)36     public static native boolean isEthernet(String iface) throws IOException;
37 
38     /**
39      * Attach a tc bpf filter.
40      *
41      * Equivalent to the following 'tc' command:
42      * tc filter add dev .. in/egress prio .. protocol ipv6/ip bpf object-pinned
43      * /sys/fs/bpf/... direct-action
44      *
45      * @param ifIndex the network interface index.
46      * @param ingress ingress or egress qdisc.
47      * @param prio
48      * @param proto
49      * @param bpfProgPath
50      * @throws IOException
51      */
tcFilterAddDevBpf(int ifIndex, boolean ingress, short prio, short proto, String bpfProgPath)52     public static native void tcFilterAddDevBpf(int ifIndex, boolean ingress, short prio,
53             short proto, String bpfProgPath) throws IOException;
54 
55     /**
56      * Attach a tc police action.
57      *
58      * Attaches a matchall filter to the clsact qdisc with a tc police and tc bpf action attached.
59      * This causes the ingress rate to be limited and exceeding packets to be forwarded to a bpf
60      * program (specified in bpfProgPah) that accounts for the packets before dropping them.
61      *
62      * Equivalent to the following 'tc' command:
63      * tc filter add dev .. ingress prio .. protocol .. matchall \
64      *     action police rate .. burst .. conform-exceed pipe/continue \
65      *     action bpf object-pinned .. \
66      *     drop
67      *
68      * @param ifIndex the network interface index.
69      * @param prio the filter preference.
70      * @param proto protocol.
71      * @param rateInBytesPerSec rate limit in bytes/s.
72      * @param bpfProgPath bpg program that accounts for rate exceeding packets before they are
73      *                    dropped.
74      * @throws IOException
75      */
tcFilterAddDevIngressPolice(int ifIndex, short prio, short proto, int rateInBytesPerSec, String bpfProgPath)76     public static native void tcFilterAddDevIngressPolice(int ifIndex, short prio, short proto,
77             int rateInBytesPerSec, String bpfProgPath) throws IOException;
78 
79     /**
80      * Delete a tc filter.
81      *
82      * Equivalent to the following 'tc' command:
83      * tc filter del dev .. in/egress prio .. protocol ..
84      *
85      * @param ifIndex the network interface index.
86      * @param ingress ingress or egress qdisc.
87      * @param prio the filter preference.
88      * @param proto protocol.
89      * @throws IOException
90      */
tcFilterDelDev(int ifIndex, boolean ingress, short prio, short proto)91     public static native void tcFilterDelDev(int ifIndex, boolean ingress, short prio,
92             short proto) throws IOException;
93 
94     /**
95      * Add a clsact qdisc.
96      *
97      * Equivalent to the following 'tc' command:
98      * tc qdisc add dev .. clsact
99      *
100      * @param ifIndex the network interface index.
101      * @throws IOException
102      */
tcQdiscAddDevClsact(int ifIndex)103     public static native void tcQdiscAddDevClsact(int ifIndex) throws IOException;
104 
105     /**
106      * Attempt to fetch a bpf program from a path.
107      * Return true on success, false on non-existence or any other failure.
108      *
109      * @param bpfProgPath
110      */
isBpfProgramUsable(String bpfProgPath)111     public static native boolean isBpfProgramUsable(String bpfProgPath);
112 }
113