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Apply IPv6 utils struct stuff to build RA packet in the Daemon.

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Traffic log of testSolicitRouterAdvertisement:
fe80::4473:4aff:fecb:7799 > ff02::1: ICMP6, router advertisement, length 88
fe80::1122:3344:5566:7788 > ff02::1: ICMP6, router solicitation, length 16
fe80::4473:4aff:fecb:7799 > fe80::1122:3344:5566:7788: ICMP6, router advertisement, length 88

Bug: 154669942
Test: atest TetheringPrivilegedTests --iterations
Change-Id: I7defb80ef9dd1832c9e04d154e1d06aed9e733dc
This commit is contained in:
Xiao Ma
2021-03-04 06:04:28 +00:00
parent 662237f2f8
commit 3e557d777a
1 changed files with 48 additions and 133 deletions
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181
Tethering/src/android/net/ip/RouterAdvertisementDaemon.java
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@@ -16,7 +16,6 @@
package android.net.ip;
import static android.net.util.NetworkConstants.IPV6_MIN_MTU;
import static android.net.util.NetworkConstants.RFC7421_PREFIX_LENGTH;
import static android.net.util.TetheringUtils.getAllNodesForScopeId;
import static android.system.OsConstants.AF_INET6;
@@ -25,8 +24,18 @@ import static android.system.OsConstants.SOCK_RAW;
import static android.system.OsConstants.SOL_SOCKET;
import static android.system.OsConstants.SO_SNDTIMEO;
import static com.android.net.module.util.NetworkStackConstants.ICMPV6_ND_OPTION_SLLA;
import static com.android.net.module.util.NetworkStackConstants.ICMPV6_RA_HEADER_LEN;
import static com.android.net.module.util.NetworkStackConstants.ICMPV6_ROUTER_ADVERTISEMENT;
import static com.android.net.module.util.NetworkStackConstants.ICMPV6_ROUTER_SOLICITATION;
import static com.android.net.module.util.NetworkStackConstants.IPV6_MIN_MTU;
import static com.android.net.module.util.NetworkStackConstants.PIO_FLAG_AUTONOMOUS;
import static com.android.net.module.util.NetworkStackConstants.PIO_FLAG_ON_LINK;
import static com.android.net.module.util.NetworkStackConstants.TAG_SYSTEM_NEIGHBOR;
import android.net.IpPrefix;
import android.net.LinkAddress;
import android.net.MacAddress;
import android.net.TrafficStats;
import android.net.util.InterfaceParams;
import android.net.util.SocketUtils;
@@ -37,7 +46,12 @@ import android.system.StructTimeval;
import android.util.Log;
import com.android.internal.annotations.GuardedBy;
import com.android.net.module.util.NetworkStackConstants;
import com.android.net.module.util.structs.Icmpv6Header;
import com.android.net.module.util.structs.LlaOption;
import com.android.net.module.util.structs.MtuOption;
import com.android.net.module.util.structs.PrefixInformationOption;
import com.android.net.module.util.structs.RaHeader;
import com.android.net.module.util.structs.RdnssOption;
import java.io.FileDescriptor;
import java.io.IOException;
@@ -69,9 +83,6 @@ import java.util.concurrent.atomic.AtomicInteger;
*/
public class RouterAdvertisementDaemon {
private static final String TAG = RouterAdvertisementDaemon.class.getSimpleName();
private static final byte ICMPV6_ND_ROUTER_SOLICIT = asByte(133);
private static final byte ICMPV6_ND_ROUTER_ADVERT = asByte(134);
private static final int MIN_RA_HEADER_SIZE = 16;
// Summary of various timers and lifetimes.
private static final int MIN_RTR_ADV_INTERVAL_SEC = 300;
@@ -366,54 +377,27 @@ public class RouterAdvertisementDaemon {
}
private static void putHeader(ByteBuffer ra, boolean hasDefaultRoute, byte hopLimit) {
/**
Router Advertisement Message Format
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Code | Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Cur Hop Limit |M|O|H|Prf|P|R|R| Router Lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reachable Time |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Retrans Timer |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Options ...
+-+-+-+-+-+-+-+-+-+-+-+-
*/
ra.put(ICMPV6_ND_ROUTER_ADVERT)
.put(asByte(0))
.putShort(asShort(0))
.put(hopLimit)
// RFC 4191 "high" preference, iff. advertising a default route.
.put(hasDefaultRoute ? asByte(0x08) : asByte(0))
.putShort(hasDefaultRoute ? asShort(DEFAULT_LIFETIME) : asShort(0))
.putInt(0)
.putInt(0);
// RFC 4191 "high" preference, iff. advertising a default route.
final byte flags = hasDefaultRoute ? asByte(0x08) : asByte(0);
final short lifetime = hasDefaultRoute ? asShort(DEFAULT_LIFETIME) : asShort(0);
final Icmpv6Header icmpv6Header =
new Icmpv6Header(asByte(ICMPV6_ROUTER_ADVERTISEMENT) /* type */,
asByte(0) /* code */, asShort(0) /* checksum */);
final RaHeader raHeader = new RaHeader(hopLimit, flags, lifetime, 0 /* reachableTime */,
0 /* retransTimer */);
icmpv6Header.writeToByteBuffer(ra);
raHeader.writeToByteBuffer(ra);
}
private static void putSlla(ByteBuffer ra, byte[] slla) {
/**
Source/Target Link-layer Address
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Link-Layer Address ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*/
if (slla == null || slla.length != 6) {
// Only IEEE 802.3 6-byte addresses are supported.
return;
}
final byte nd_option_slla = 1;
final byte slla_num_8octets = 1;
ra.put(nd_option_slla)
.put(slla_num_8octets)
.put(slla);
final ByteBuffer sllaOption = LlaOption.build(asByte(ICMPV6_ND_OPTION_SLLA),
MacAddress.fromBytes(slla));
ra.put(sllaOption);
}
private static void putExpandedFlagsOption(ByteBuffer ra) {
@@ -439,70 +423,24 @@ public class RouterAdvertisementDaemon {
}
private static void putMtu(ByteBuffer ra, int mtu) {
/**
MTU
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MTU |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*/
final byte nd_option_mtu = 5;
final byte mtu_num_8octs = 1;
ra.put(nd_option_mtu)
.put(mtu_num_8octs)
.putShort(asShort(0))
.putInt((mtu < IPV6_MIN_MTU) ? IPV6_MIN_MTU : mtu);
final ByteBuffer mtuOption = MtuOption.build((mtu < IPV6_MIN_MTU) ? IPV6_MIN_MTU : mtu);
ra.put(mtuOption);
}
private static void putPio(ByteBuffer ra, IpPrefix ipp,
int validTime, int preferredTime) {
/**
Prefix Information
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Prefix Length |L|A| Reserved1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Valid Lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Preferred Lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Prefix +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*/
final int prefixLength = ipp.getPrefixLength();
if (prefixLength != 64) {
return;
}
final byte nd_option_pio = 3;
final byte pio_num_8octets = 4;
if (validTime < 0) validTime = 0;
if (preferredTime < 0) preferredTime = 0;
if (preferredTime > validTime) preferredTime = validTime;
final byte[] addr = ipp.getAddress().getAddress();
ra.put(nd_option_pio)
.put(pio_num_8octets)
.put(asByte(prefixLength))
.put(asByte(0xc0)) /* L & A set */
.putInt(validTime)
.putInt(preferredTime)
.putInt(0)
.put(addr);
final ByteBuffer pioOption = PrefixInformationOption.build(ipp,
asByte(PIO_FLAG_ON_LINK | PIO_FLAG_AUTONOMOUS), validTime, preferredTime);
ra.put(pioOption);
}
private static void putRio(ByteBuffer ra, IpPrefix ipp) {
@@ -543,22 +481,6 @@ public class RouterAdvertisementDaemon {
}
private static void putRdnss(ByteBuffer ra, Set<Inet6Address> dnses, int lifetime) {
/**
Recursive DNS Server (RDNSS) Option
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
: Addresses of IPv6 Recursive DNS Servers :
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*/
final HashSet<Inet6Address> filteredDnses = new HashSet<>();
for (Inet6Address dns : dnses) {
if ((new LinkAddress(dns, RFC7421_PREFIX_LENGTH)).isGlobalPreferred()) {
@@ -567,29 +489,22 @@ public class RouterAdvertisementDaemon {
}
if (filteredDnses.isEmpty()) return;
final byte nd_option_rdnss = 25;
final byte rdnss_num_8octets = asByte(dnses.size() * 2 + 1);
ra.put(nd_option_rdnss)
.put(rdnss_num_8octets)
.putShort(asShort(0))
.putInt(lifetime);
for (Inet6Address dns : filteredDnses) {
// NOTE: If the full of list DNS servers doesn't fit in the packet,
// this code will cause a buffer overflow and the RA won't include
// this instance of the option at all.
//
// TODO: Consider looking at ra.remaining() to determine how many
// DNS servers will fit, and adding only those.
ra.put(dns.getAddress());
}
final Inet6Address[] dnsesArray =
filteredDnses.toArray(new Inet6Address[filteredDnses.size()]);
final ByteBuffer rdnssOption = RdnssOption.build(lifetime, dnsesArray);
// NOTE: If the full of list DNS servers doesn't fit in the packet,
// this code will cause a buffer overflow and the RA won't include
// this instance of the option at all.
//
// TODO: Consider looking at ra.remaining() to determine how many
// DNS servers will fit, and adding only those.
ra.put(rdnssOption);
}
private boolean createSocket() {
final int send_timout_ms = 300;
final int oldTag = TrafficStats.getAndSetThreadStatsTag(
NetworkStackConstants.TAG_SYSTEM_NEIGHBOR);
final int oldTag = TrafficStats.getAndSetThreadStatsTag(TAG_SYSTEM_NEIGHBOR);
try {
mSocket = Os.socket(AF_INET6, SOCK_RAW, IPPROTO_ICMPV6);
// Setting SNDTIMEO is purely for defensive purposes.
@@ -639,7 +554,7 @@ public class RouterAdvertisementDaemon {
try {
synchronized (mLock) {
if (mRaLength < MIN_RA_HEADER_SIZE) {
if (mRaLength < ICMPV6_RA_HEADER_LEN) {
// No actual RA to send.
return;
}
@@ -668,7 +583,7 @@ public class RouterAdvertisementDaemon {
final int rval = Os.recvfrom(
mSocket, mSolicitation, 0, mSolicitation.length, 0, mSolicitor);
// Do the least possible amount of validation.
if (rval < 1 || mSolicitation[0] != ICMPV6_ND_ROUTER_SOLICIT) {
if (rval < 1 || mSolicitation[0] != asByte(ICMPV6_ROUTER_SOLICITATION)) {
continue;
}
} catch (ErrnoException | SocketException e) {
@@ -721,7 +636,7 @@ public class RouterAdvertisementDaemon {
private int getNextMulticastTransmitDelaySec() {
boolean deprecationInProgress = false;
synchronized (mLock) {
if (mRaLength < MIN_RA_HEADER_SIZE) {
if (mRaLength < ICMPV6_RA_HEADER_LEN) {
// No actual RA to send; just sleep for 1 day.
return DAY_IN_SECONDS;
}