Move attach*Filter() and addArpEntry() methods to NetworkStack

The SocketUtils.attach*Filter and SocketUtils.addArpEntry methods
were added there because they could not be added as JNI inside
the NetworkStack. This was not possible because on Go devices,
the NetworkStack was a jar library. But now, Go also uses an APK.
Hence, move these methods to the NetworkStack.

Change-Id: I1d88a0f0be23f2b15d5103fa092b9bf982329d7c
Fix: 129433183
Test: atest NetworkStackTests FrameworksNetTests

1 files changed, 264 insertions, 0 deletions

diff --git a/jni/network_stack_utils_jni.cpp b/jni/network_stack_utils_jni.cpp
new file mode 100644
index 00000000..5544eaa8
--- /dev/null
+++ b/jni/network_stack_utils_jni.cpp
@@ -0,0 +1,264 @@
+/*
+ * Copyright 2019, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "NetworkStackUtils-JNI"
+
+#include <errno.h>
+#include <jni.h>
+#include <linux/filter.h>
+#include <linux/if_arp.h>
+#include <net/if.h>
+#include <netinet/ether.h>
+#include <netinet/icmp6.h>
+#include <netinet/ip.h>
+#include <netinet/ip6.h>
+#include <netinet/udp.h>
+#include <stdlib.h>
+
+#include <string>
+
+#include <nativehelper/JNIHelp.h>
+#include <utils/Log.h>
+
+namespace android {
+constexpr const char NETWORKSTACKUTILS_PKG_NAME[] = "android/net/util/NetworkStackUtils";
+
+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 bool checkLenAndCopy(JNIEnv* env, const jbyteArray& addr, int len, void* dst) {
+    if (env->GetArrayLength(addr) != len) {
+        return false;
+    }
+    env->GetByteArrayRegion(addr, 0, len, reinterpret_cast<jbyte*>(dst));
+    return true;
+}
+
+static void network_stack_utils_addArpEntry(JNIEnv *env, jobject thiz, jbyteArray ethAddr,
+        jbyteArray ipv4Addr, jstring ifname, jobject javaFd) {
+    arpreq req = {};
+    sockaddr_in& netAddrStruct = *reinterpret_cast<sockaddr_in*>(&req.arp_pa);
+    sockaddr& ethAddrStruct = req.arp_ha;
+
+    ethAddrStruct.sa_family = ARPHRD_ETHER;
+    if (!checkLenAndCopy(env, ethAddr, ETH_ALEN, ethAddrStruct.sa_data)) {
+        jniThrowException(env, "java/io/IOException", "Invalid ethAddr length");
+        return;
+    }
+
+    netAddrStruct.sin_family = AF_INET;
+    if (!checkLenAndCopy(env, ipv4Addr, sizeof(in_addr), &netAddrStruct.sin_addr)) {
+        jniThrowException(env, "java/io/IOException", "Invalid ipv4Addr length");
+        return;
+    }
+
+    int ifLen = env->GetStringLength(ifname);
+    // IFNAMSIZ includes the terminating NULL character
+    if (ifLen >= IFNAMSIZ) {
+        jniThrowException(env, "java/io/IOException", "ifname too long");
+        return;
+    }
+    env->GetStringUTFRegion(ifname, 0, ifLen, req.arp_dev);
+
+    req.arp_flags = ATF_COM;  // Completed entry (ha valid)
+    int fd = jniGetFDFromFileDescriptor(env, javaFd);
+    if (fd < 0) {
+        jniThrowExceptionFmt(env, "java/io/IOException", "Invalid file descriptor");
+        return;
+    }
+    // See also: man 7 arp
+    if (ioctl(fd, SIOCSARP, &req)) {
+        jniThrowExceptionFmt(env, "java/io/IOException", "ioctl error: %s", strerror(errno));
+        return;
+    }
+}
+
+static void network_stack_utils_attachDhcpFilter(JNIEnv *env, jobject clazz, jobject javaFd) {
+    static sock_filter filter_code[] = {
+        // 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, 6),
+
+        // 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, 4, 0),
+
+        // Get the IP header length.
+        BPF_STMT(BPF_LDX | BPF_B    | BPF_MSH, kEtherHeaderLen),
+
+        // Check the destination port.
+        BPF_STMT(BPF_LD  | BPF_H    | BPF_IND, kUDPDstPortIndirectOffset),
+        BPF_JUMP(BPF_JMP | BPF_JEQ  | BPF_K,   kDhcpClientPort, 0, 1),
+
+        // Accept or reject.
+        BPF_STMT(BPF_RET | BPF_K,              0xffff),
+        BPF_STMT(BPF_RET | BPF_K,              0)
+    };
+    static const 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 network_stack_utils_attachRaFilter(JNIEnv *env, jobject clazz, jobject javaFd,
+        jint hardwareAddressType) {
+    if (hardwareAddressType != ARPHRD_ETHER) {
+        jniThrowExceptionFmt(env, "java/net/SocketException",
+                "attachRaFilter only supports ARPHRD_ETHER");
+        return;
+    }
+
+    static sock_filter filter_code[] = {
+        // Check IPv6 Next Header is ICMPv6.
+        BPF_STMT(BPF_LD  | BPF_B   | BPF_ABS,  kIPv6NextHeader),
+        BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K,    IPPROTO_ICMPV6, 0, 3),
+
+        // Check ICMPv6 type is Router Advertisement.
+        BPF_STMT(BPF_LD  | BPF_B   | BPF_ABS,  kICMPv6TypeOffset),
+        BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K,    ND_ROUTER_ADVERT, 0, 1),
+
+        // Accept or reject.
+        BPF_STMT(BPF_RET | BPF_K,              0xffff),
+        BPF_STMT(BPF_RET | BPF_K,              0)
+    };
+    static const 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));
+    }
+}
+
+// TODO: Move all this filter code into libnetutils.
+static void network_stack_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)'
+    static 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)
+    };
+    static const 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));
+    }
+}
+
+/*
+ * JNI registration.
+ */
+static const JNINativeMethod gNetworkStackUtilsMethods[] = {
+    /* name, signature, funcPtr */
+    { "addArpEntry", "([B[BLjava/lang/String;Ljava/io/FileDescriptor;)V", (void*) network_stack_utils_addArpEntry },
+    { "attachDhcpFilter", "(Ljava/io/FileDescriptor;)V", (void*) network_stack_utils_attachDhcpFilter },
+    { "attachRaFilter", "(Ljava/io/FileDescriptor;I)V", (void*) network_stack_utils_attachRaFilter },
+    { "attachControlPacketFilter", "(Ljava/io/FileDescriptor;I)V", (void*) network_stack_utils_attachControlPacketFilter },
+};
+
+extern "C" jint JNI_OnLoad(JavaVM* vm, void*) {
+    JNIEnv *env;
+    if (vm->GetEnv(reinterpret_cast<void**>(&env), JNI_VERSION_1_6) != JNI_OK) {
+        ALOGE("ERROR: GetEnv failed");
+        return JNI_ERR;
+    }
+
+    if (jniRegisterNativeMethods(env, NETWORKSTACKUTILS_PKG_NAME,
+            gNetworkStackUtilsMethods, NELEM(gNetworkStackUtilsMethods)) < 0) {
+        return JNI_ERR;
+    }
+
+    return JNI_VERSION_1_6;
+
+}
+}; // namespace android
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