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Merge "Have IpManager track L2-L4 signaling traffic required for IP connectivity."

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am: 80ff5ecd4a

Change-Id: If85702e1cc44967841ab91d723aa627862bcda21
This commit is contained in:
Erik Kline
2016-12-15 12:22:06 +00:00
committed by android-build-merger
parent 7b5f0a82d0 867dfd1057
commit 4f4a914a0f
2 changed files with 103 additions and 15 deletions
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11
core/java/android/net/NetworkUtils.java
View File

@@ -51,6 +51,17 @@ public class NetworkUtils {
*/ */
public native static void attachRaFilter(FileDescriptor fd, int packetType) throws SocketException; public native static void attachRaFilter(FileDescriptor fd, int packetType) throws SocketException;
/**
* Attaches a socket filter that accepts L2-L4 signaling traffic required for IP connectivity.
*
* This includes: all ARP, ICMPv6 RS/RA/NS/NA messages, and DHCPv4 exchanges.
*
* @param fd the socket's {@link FileDescriptor}.
* @param packetType the hardware address type, one of ARPHRD_*.
*/
public native static void attachControlPacketFilter(FileDescriptor fd, int packetType)
throws SocketException;
/** /**
* Configures a socket for receiving ICMPv6 router solicitations and sending advertisements. * Configures a socket for receiving ICMPv6 router solicitations and sending advertisements.
* @param fd the socket's {@link FileDescriptor}. * @param fd the socket's {@link FileDescriptor}.

107
core/jni/android_net_NetUtils.cpp
View File

@@ -44,28 +44,33 @@ int ifc_disable(const char *ifname);
namespace android { namespace android {
static const uint32_t kEtherTypeOffset = offsetof(ether_header, ether_type);
static const uint32_t kEtherHeaderLen = sizeof(ether_header);
static const uint32_t kIPv4Protocol = kEtherHeaderLen + offsetof(iphdr, protocol);
static const uint32_t kIPv4FlagsOffset = kEtherHeaderLen + offsetof(iphdr, frag_off);
static const uint32_t kIPv6NextHeader = kEtherHeaderLen + offsetof(ip6_hdr, ip6_nxt);
static const uint32_t kIPv6PayloadStart = kEtherHeaderLen + sizeof(ip6_hdr);
static const uint32_t kICMPv6TypeOffset = kIPv6PayloadStart + offsetof(icmp6_hdr, icmp6_type);
static const uint32_t kUDPSrcPortIndirectOffset = kEtherHeaderLen + offsetof(udphdr, source);
static const uint32_t kUDPDstPortIndirectOffset = kEtherHeaderLen + offsetof(udphdr, dest);
static const uint16_t kDhcpClientPort = 68; static const uint16_t kDhcpClientPort = 68;
static void android_net_utils_attachDhcpFilter(JNIEnv *env, jobject clazz, jobject javaFd) static void android_net_utils_attachDhcpFilter(JNIEnv *env, jobject clazz, jobject javaFd)
{ {
uint32_t ip_offset = sizeof(ether_header);
uint32_t proto_offset = ip_offset + offsetof(iphdr, protocol);
uint32_t flags_offset = ip_offset + offsetof(iphdr, frag_off);
uint32_t dport_indirect_offset = ip_offset + offsetof(udphdr, dest);
struct sock_filter filter_code[] = { struct sock_filter filter_code[] = {
// Check the protocol is UDP. // Check the protocol is UDP.
BPF_STMT(BPF_LD | BPF_B | BPF_ABS, proto_offset), BPF_STMT(BPF_LD | BPF_B | BPF_ABS, kIPv4Protocol),
BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, IPPROTO_UDP, 0, 6), BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, IPPROTO_UDP, 0, 6),
// Check this is not a fragment. // Check this is not a fragment.
BPF_STMT(BPF_LD | BPF_H | BPF_ABS, flags_offset), BPF_STMT(BPF_LD | BPF_H | BPF_ABS, kIPv4FlagsOffset),
BPF_JUMP(BPF_JMP | BPF_JSET | BPF_K, 0x1fff, 4, 0), BPF_JUMP(BPF_JMP | BPF_JSET | BPF_K, IP_OFFMASK, 4, 0),
// Get the IP header length. // Get the IP header length.
BPF_STMT(BPF_LDX | BPF_B | BPF_MSH, ip_offset), BPF_STMT(BPF_LDX | BPF_B | BPF_MSH, kEtherHeaderLen),
// Check the destination port. // Check the destination port.
BPF_STMT(BPF_LD | BPF_H | BPF_IND, dport_indirect_offset), BPF_STMT(BPF_LD | BPF_H | BPF_IND, kUDPDstPortIndirectOffset),
BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, kDhcpClientPort, 0, 1), BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, kDhcpClientPort, 0, 1),
// Accept or reject. // Accept or reject.
@@ -93,17 +98,13 @@ static void android_net_utils_attachRaFilter(JNIEnv *env, jobject clazz, jobject
return; return;
} }
uint32_t ipv6_offset = sizeof(ether_header);
uint32_t ipv6_next_header_offset = ipv6_offset + offsetof(ip6_hdr, ip6_nxt);
uint32_t icmp6_offset = ipv6_offset + sizeof(ip6_hdr);
uint32_t icmp6_type_offset = icmp6_offset + offsetof(icmp6_hdr, icmp6_type);
struct sock_filter filter_code[] = { struct sock_filter filter_code[] = {
// Check IPv6 Next Header is ICMPv6. // Check IPv6 Next Header is ICMPv6.
BPF_STMT(BPF_LD | BPF_B | BPF_ABS, ipv6_next_header_offset), BPF_STMT(BPF_LD | BPF_B | BPF_ABS, kIPv6NextHeader),
BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, IPPROTO_ICMPV6, 0, 3), BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, IPPROTO_ICMPV6, 0, 3),
// Check ICMPv6 type is Router Advertisement. // Check ICMPv6 type is Router Advertisement.
BPF_STMT(BPF_LD | BPF_B | BPF_ABS, icmp6_type_offset), BPF_STMT(BPF_LD | BPF_B | BPF_ABS, kICMPv6TypeOffset),
BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, ND_ROUTER_ADVERT, 0, 1), BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, ND_ROUTER_ADVERT, 0, 1),
// Accept or reject. // Accept or reject.
@@ -122,6 +123,81 @@ static void android_net_utils_attachRaFilter(JNIEnv *env, jobject clazz, jobject
} }
} }
// TODO: Move all this filter code into libnetutils.
static void android_net_utils_attachControlPacketFilter(
JNIEnv *env, jobject clazz, jobject javaFd, jint hardwareAddressType) {
if (hardwareAddressType != ARPHRD_ETHER) {
jniThrowExceptionFmt(env, "java/net/SocketException",
"attachControlPacketFilter only supports ARPHRD_ETHER");
return;
}
// Capture all:
// - ARPs
// - DHCPv4 packets
// - Router Advertisements & Solicitations
// - Neighbor Advertisements & Solicitations
//
// tcpdump:
// arp or
// '(ip and udp port 68)' or
// '(icmp6 and ip6[40] >= 133 and ip6[40] <= 136)'
struct sock_filter filter_code[] = {
// Load the link layer next payload field.
BPF_STMT(BPF_LD | BPF_H | BPF_ABS, kEtherTypeOffset),
// Accept all ARP.
// TODO: Figure out how to better filter ARPs on noisy networks.
BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, ETHERTYPE_ARP, 16, 0),
// If IPv4:
BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, ETHERTYPE_IP, 0, 9),
// Check the protocol is UDP.
BPF_STMT(BPF_LD | BPF_B | BPF_ABS, kIPv4Protocol),
BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, IPPROTO_UDP, 0, 14),
// Check this is not a fragment.
BPF_STMT(BPF_LD | BPF_H | BPF_ABS, kIPv4FlagsOffset),
BPF_JUMP(BPF_JMP | BPF_JSET | BPF_K, IP_OFFMASK, 12, 0),
// Get the IP header length.
BPF_STMT(BPF_LDX | BPF_B | BPF_MSH, kEtherHeaderLen),
// Check the source port.
BPF_STMT(BPF_LD | BPF_H | BPF_IND, kUDPSrcPortIndirectOffset),
BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, kDhcpClientPort, 8, 0),
// Check the destination port.
BPF_STMT(BPF_LD | BPF_H | BPF_IND, kUDPDstPortIndirectOffset),
BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, kDhcpClientPort, 6, 7),
// IPv6 ...
BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, ETHERTYPE_IPV6, 0, 6),
// ... check IPv6 Next Header is ICMPv6 (ignore fragments), ...
BPF_STMT(BPF_LD | BPF_B | BPF_ABS, kIPv6NextHeader),
BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, IPPROTO_ICMPV6, 0, 4),
// ... and check the ICMPv6 type is one of RS/RA/NS/NA.
BPF_STMT(BPF_LD | BPF_B | BPF_ABS, kICMPv6TypeOffset),
BPF_JUMP(BPF_JMP | BPF_JGE | BPF_K, ND_ROUTER_SOLICIT, 0, 2),
BPF_JUMP(BPF_JMP | BPF_JGT | BPF_K, ND_NEIGHBOR_ADVERT, 1, 0),
// Accept or reject.
BPF_STMT(BPF_RET | BPF_K, 0xffff),
BPF_STMT(BPF_RET | BPF_K, 0)
};
struct sock_fprog filter = {
sizeof(filter_code) / sizeof(filter_code[0]),
filter_code,
};
int fd = jniGetFDFromFileDescriptor(env, javaFd);
if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter)) != 0) {
jniThrowExceptionFmt(env, "java/net/SocketException",
"setsockopt(SO_ATTACH_FILTER): %s", strerror(errno));
}
}
static void android_net_utils_setupRaSocket(JNIEnv *env, jobject clazz, jobject javaFd, static void android_net_utils_setupRaSocket(JNIEnv *env, jobject clazz, jobject javaFd,
jint ifIndex) jint ifIndex)
{ {
@@ -263,6 +339,7 @@ static const JNINativeMethod gNetworkUtilMethods[] = {
{ "queryUserAccess", "(II)Z", (void*)android_net_utils_queryUserAccess }, { "queryUserAccess", "(II)Z", (void*)android_net_utils_queryUserAccess },
{ "attachDhcpFilter", "(Ljava/io/FileDescriptor;)V", (void*) android_net_utils_attachDhcpFilter }, { "attachDhcpFilter", "(Ljava/io/FileDescriptor;)V", (void*) android_net_utils_attachDhcpFilter },
{ "attachRaFilter", "(Ljava/io/FileDescriptor;I)V", (void*) android_net_utils_attachRaFilter }, { "attachRaFilter", "(Ljava/io/FileDescriptor;I)V", (void*) android_net_utils_attachRaFilter },
{ "attachControlPacketFilter", "(Ljava/io/FileDescriptor;I)V", (void*) android_net_utils_attachControlPacketFilter },
{ "setupRaSocket", "(Ljava/io/FileDescriptor;I)V", (void*) android_net_utils_setupRaSocket }, { "setupRaSocket", "(Ljava/io/FileDescriptor;I)V", (void*) android_net_utils_setupRaSocket },
}; };