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Code Issues Releases Wiki Activity

Native SYN forward

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This commit is contained in:
M66B 2016-01-11 23:06:35 +01:00
parent 4a0adc143e
commit 806196bc69
4 changed files with 211 additions and 15 deletions
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1
app/proguard-rules.pro vendored
View file

@ -26,6 +26,7 @@
# logPacket(int version, String saddr, int sport, String daddr, int dport, int protocol, String flags, int uid)
-keep class eu.faircode.netguard.SinkholeService {
void logPacket(int, java.lang.String, int, java.lang.String, int, int, java.lang.String, int);
void protectSocket(int);
}
#Support library

1
app/src/main/AndroidManifest.xml
View file

@ -8,6 +8,7 @@
<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
<uses-permission android:name="android.permission.WAKE_LOCK" />
<uses-permission android:name="com.android.vending.BILLING" />
<uses-permission android:name="android.permission.INTERNET" />
<!-- http://developer.android.com/guide/topics/security/permissions.html#normal-dangerous -->
<uses-feature

10
app/src/main/java/eu/faircode/netguard/SinkholeService.java
View file

@ -64,6 +64,7 @@ import android.widget.RemoteViews;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.net.Socket;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.Date;
@ -749,6 +750,15 @@ public class SinkholeService extends VpnService implements SharedPreferences.OnS
last_interactive).close();
}
private void protectSocket(int socket) {
try {
if (!protect(socket))
Log.e(TAG, "Failed to protect socket");
} catch (Throwable ex) {
Log.e(TAG, ex.toString() + "\n" + Log.getStackTraceString(ex));
}
}
private void stopReceiving() {
if (receiveThread != null)
receiveThread.interrupt();

214
app/src/main/jni/netguard/netguard.c
View file

@ -9,16 +9,42 @@
#include <netinet/udp.h>
#include <netinet/tcp.h>
// This should go into a header file later
#define TAG "NetGuard.JNI"
#define MAXPKT 32768
struct packet {
void *data;
struct packet *next;
};
struct connection {
int32_t saddr;
__be16 source;
int32_t daddr;
__be16 dest;
int state;
int socket;
struct packet *packet;
struct connection *next;
};
struct connection *connection = NULL;
void decode(JNIEnv *env, jobject instance, jbyte *, int);
int getUid(int, int, void *, int);
void handle_tcp4(JNIEnv *, jobject, void *, int);
void poll();
// JNI interface
JNIEXPORT void JNICALL
Java_eu_faircode_netguard_SinkholeService_jni_1init(JNIEnv *env, jobject instance) {
__android_log_print(ANDROID_LOG_INFO, TAG, "Init", 1);
__android_log_print(ANDROID_LOG_INFO, TAG, "Init");
}
JNIEXPORT void JNICALL
@ -36,7 +62,7 @@ Java_eu_faircode_netguard_SinkholeService_jni_1receive(JNIEnv *env, jobject inst
while (1) {
len = read(fd, buffer, sizeof(buffer));
if (len < 0) {
__android_log_print(ANDROID_LOG_WARN, TAG, "Receive error %d", len);
__android_log_print(ANDROID_LOG_WARN, TAG, "Receive error=%d", len);
return;
} else if (len > 0)
@ -47,6 +73,159 @@ Java_eu_faircode_netguard_SinkholeService_jni_1receive(JNIEnv *env, jobject inst
}
}
// Private functions
void poll() {
struct connection *last = NULL;
struct connection *cur = connection;
while (cur != NULL) {
if (cur->state == TCP_SYN_RECV) {
// Log
char dest[20];
inet_ntop(AF_INET, &(cur->daddr), dest, sizeof(dest));
__android_log_print(ANDROID_LOG_DEBUG, TAG, "SYN poll %s/%d", dest, ntohs(cur->dest));
// Check connection state
fd_set wfds;
FD_ZERO(&wfds);
FD_SET(cur->socket, &wfds);
struct timeval tv;
tv.tv_sec = 0;
tv.tv_usec = 0;
int ready = select(1, NULL, &wfds, NULL, &tv);
if (ready < 0) {
// TODO
__android_log_print(ANDROID_LOG_ERROR, TAG, "select error %d: %s", errno,
strerror(errno));
continue;
}
// Connected
if (ready == 1) {
__android_log_print(ANDROID_LOG_INFO, TAG, "Established");
// Send ACK
cur->state = TCP_ESTABLISHED;
if (last == NULL)
connection = cur->next;
else
last->next = cur->next;
free(cur->packet);
free(cur);
} else {
// TODO
__android_log_print(ANDROID_LOG_ERROR, TAG, "Connecting");
}
}
cur = cur->next;
}
}
void handle_tcp4(JNIEnv *env, jobject instance, void *buffer, int len) {
// Copy buffer
jbyte *copy = malloc(len); // TODO free
memcpy(copy, buffer, len);
// Get headers
struct iphdr *iphdr = copy;
jbyte optlen = (iphdr->ihl > 5 ? copy[20] : 0);
struct tcphdr *tcphdr = buffer + (20 + optlen) * sizeof(jbyte);
// Search connection
struct connection *last = NULL;
struct connection *cur = connection;
while (cur != NULL && !(cur->saddr == iphdr->saddr && cur->source != tcphdr->source)) {
last = cur;
cur = cur->next;
}
// Log
char dest[20];
inet_ntop(AF_INET, &(iphdr->daddr), dest, sizeof(dest));
if (cur == NULL) {
if (tcphdr->syn) {
__android_log_print(ANDROID_LOG_INFO, TAG, "SYN %s/%d", dest, ntohs(tcphdr->dest));
// Register connection
struct connection *syn = malloc(sizeof(struct connection));
syn->saddr = iphdr->saddr;
syn->source = tcphdr->source;
syn->daddr = iphdr->daddr;
syn->dest = tcphdr->dest;
syn->state = TCP_SYN_RECV;
syn->packet = malloc(sizeof(struct packet)); // TODO free
syn->packet->data = copy;
syn->packet->next = NULL;
syn->next = NULL;
if (last == NULL)
connection = syn;
else
last->next = syn;
// Get TCP socket
if ((syn->socket = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
// TODO
__android_log_print(ANDROID_LOG_ERROR, TAG, "socket error %d: %s", errno,
strerror(errno));
syn->state = TCP_CLOSE;
return;
}
// Set non blocking
int flags = fcntl(syn->socket, F_GETFL, 0);
if (fcntl(syn->socket, F_SETFL, flags | O_NONBLOCK) < 0) {
// TODO
__android_log_print(ANDROID_LOG_ERROR, TAG, "fcntl error %d: %s", errno,
strerror(errno));
syn->state = TCP_CLOSE;
return;
}
// Protect
jclass cls = (*env)->GetObjectClass(env, instance);
// TODO: call VpnService.protect
jmethodID mid = (*env)->GetMethodID(env, cls, "protectSocket", "(I)V");
if (mid == 0) {
__android_log_print(ANDROID_LOG_ERROR, TAG, "protectSocket not found");
syn->state = TCP_CLOSE;
return;
}
else {
(*env)->CallVoidMethod(env, instance, mid, syn->socket);
// TODO handle exceptions
}
// Target address
struct sockaddr_in a;
memset(&a, 0, sizeof(struct sockaddr_in));
a.sin_family = AF_INET;
a.sin_port = tcphdr->dest;
a.sin_addr.s_addr = iphdr->daddr;
int err = connect(syn->socket, &a, sizeof(struct sockaddr_in));
if (err < 0 && errno != EINPROGRESS) {
// TODO
__android_log_print(ANDROID_LOG_ERROR, TAG, "connect error %d: %s", errno,
strerror(errno));
syn->state = TCP_CLOSE;
return;
}
__android_log_print(ANDROID_LOG_INFO, TAG, "Connecting to %s/%d", dest,
ntohs(tcphdr->dest));
}
}
else {
if (tcphdr->syn) {
// TODO
__android_log_print(ANDROID_LOG_INFO, TAG, "SYNx2 %s/%d", dest, ntohs(tcphdr->dest));
}
}
}
void decode(JNIEnv *env, jobject instance, jbyte *buffer, int length) {
jbyte protocol;
void *saddr;
@ -69,10 +248,8 @@ void decode(JNIEnv *env, jobject instance, jbyte *buffer, int length) {
if (ip4hdr->frag_off & IP_MF)
flags[flen++] = '+';
jbyte optlen = 0;
if (ip4hdr->ihl > 5)
optlen = buffer[20];
payload = buffer + (20 + optlen) * sizeof(jbyte);
jbyte optlen = (ip4hdr->ihl > 5 ? buffer[20] : 0);
payload = buffer + 20 + optlen;
}
else if (version == 6) {
struct ip6_hdr *ip6hdr = buffer;
@ -81,13 +258,16 @@ void decode(JNIEnv *env, jobject instance, jbyte *buffer, int length) {
saddr = &ip6hdr->ip6_src;
daddr = &ip6hdr->ip6_dst;
payload = buffer + 40 * sizeof(jbyte);
payload = buffer + 40;
}
else {
__android_log_print(ANDROID_LOG_WARN, TAG, "Unknown version %d", version);
__android_log_print(ANDROID_LOG_WARN, TAG, "Unknown version=%d", version);
return;
}
inet_ntop(version == 4 ? AF_INET : AF_INET6, saddr, source, sizeof(source));
inet_ntop(version == 4 ? AF_INET : AF_INET6, daddr, dest, sizeof(dest));
// Get ports & flags
int sport = -1;
int dport = -1;
@ -113,14 +293,8 @@ void decode(JNIEnv *env, jobject instance, jbyte *buffer, int length) {
sport = ntohs(udp->source);
dport = ntohs(udp->dest);
}
flags[flen] = 0;
inet_ntop(version == 4 ? AF_INET : AF_INET6, saddr, source, sizeof(source));
inet_ntop(version == 4 ? AF_INET : AF_INET6, daddr, dest, sizeof(dest));
// __android_log_print(ANDROID_LOG_INFO, TAG, "Packet v%d %s/%d -> %s/%d proto %d flags %s",
// version, source, sport, dest, dport, protocol, flags);
// Get uid
int uid = -1;
if (protocol == IPPROTO_TCP || protocol == IPPROTO_UDP) {
@ -142,11 +316,21 @@ void decode(JNIEnv *env, jobject instance, jbyte *buffer, int length) {
}
}
/*
__android_log_print(ANDROID_LOG_INFO, TAG, "Packet v%d %s/%d -> %s/%d proto %d flags %s uid %d",
version, source, sport, dest, dport, protocol, flags, uid);
poll();
if (protocol == IPPROTO_TCP && version == 4)
handle_tcp4(env, instance, buffer, length);
*/
// Call back
jclass cls = (*env)->GetObjectClass(env, instance);
jmethodID mid = (*env)->GetMethodID(env, cls, "logPacket",
"(ILjava/lang/String;ILjava/lang/String;IILjava/lang/String;I)V");
if (mid != 0) {
if (mid == 0)
__android_log_print(ANDROID_LOG_ERROR, TAG, "logPacket not found");
else {
jstring jsource = (*env)->NewStringUTF(env, source);
jstring jdest = (*env)->NewStringUTF(env, dest);
jstring jflags = (*env)->NewStringUTF(env, flags);