mirror
/
NetGuard
mirror of https://github.com/M66B/NetGuard.git
1
0
Fork 0
Code Issues Releases Wiki Activity

Native rough FIN

This commit is contained in:
M66B 2016-01-14 22:48:05 +01:00
parent 12e701004b
commit 65cc667d71
1 changed files with 31 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

38
app/src/main/jni/netguard/netguard.c
View File

@ -67,7 +67,7 @@ int canWrite(const int);
int writeSYN(const struct connection *, const int);
int writeACK(const struct connection *, struct data *, uint16_t confirm, int);
int writeACK(const struct connection *, struct data *, uint16_t, int, int);
void decode(JNIEnv *, jobject, const struct arguments *args, const uint8_t *, const uint16_t);
@ -358,7 +358,8 @@ void *handle_events(void *a) {
data->data = malloc(bytes);
memcpy(data->data, buffer, bytes);
// canWrite(args->tun)
writeACK(cur, data, 0, args->tun);
writeACK(cur, data, 0, 0, args->tun);
// TODO check result
// TODO retransmits
free(data->data);
free(data);
@ -480,7 +481,7 @@ void handle_tcp(JNIEnv *env, jobject instance, const struct arguments *args,
if (tcphdr->syn)
__android_log_print(ANDROID_LOG_DEBUG, TAG, "Ignoring repeated SYN");
else if (tcphdr->ack) {
if (tcphdr->ack) {
cur->time = time(NULL);
if (cur->state == TCP_SYN_SENT) {
@ -515,17 +516,39 @@ void handle_tcp(JNIEnv *env, jobject instance, const struct arguments *args,
__android_log_print(ANDROID_LOG_ERROR, TAG, "send error %d: %s",
errno, strerror(errno));
else {
if (writeACK(cur, NULL, data->len, args->tun))
if (writeACK(cur, NULL, data->len, 0, args->tun))
cur->remote_seq += data->len;
}
}
}
}
else if (cur->state == TCP_LAST_ACK) {
// TODO check seq/ack
__android_log_print(ANDROID_LOG_DEBUG, TAG, "Full close");
cur->state = TCP_CLOSE;
}
else {
__android_log_print(ANDROID_LOG_WARN, TAG, "Ignored state %d", cur->state);
}
}
if (tcphdr->fin) {
if (cur->state == TCP_ESTABLISHED) {
// TODO close socket
__android_log_print(ANDROID_LOG_DEBUG, TAG, "Partial close");
if (writeACK(cur, NULL, 1, 1, args->tun) >= 0) {
cur->local_seq += 1;
cur->remote_seq += 1;
cur->state = TCP_LAST_ACK;
}
}
}
if (tcphdr->rst) {
cur->state = TCP_CLOSE;
}
}
}
@ -673,7 +696,7 @@ int writeSYN(const struct connection *cur, int tun) {
return res;
}
int writeACK(const struct connection *cur, struct data *data, uint16_t confirm, int tun) {
int writeACK(const struct connection *cur, struct data *data, uint16_t confirm, int fin, int tun) {
// Build packet
uint16_t datalen = (data == NULL ? 0 : data->len);
uint16_t len = sizeof(struct iphdr) + sizeof(struct tcphdr) + datalen; // no data
@ -702,6 +725,7 @@ int writeACK(const struct connection *cur, struct data *data, uint16_t confirm,
tcp->ack_seq = htonl(cur->remote_seq + confirm); // TODO proper wrap around
tcp->doff = sizeof(struct tcphdr) >> 2;
tcp->ack = 1;
tcp->fin = fin;
tcp->window = htons(2048);
// Calculate TCP checksum
@ -728,8 +752,8 @@ int writeACK(const struct connection *cur, struct data *data, uint16_t confirm,
// Send packet
__android_log_print(ANDROID_LOG_DEBUG, TAG,
"Sending ACK to tun %s/%u seq %u ack %u data %u confirm %u",
to, ntohs(tcp->dest),
"Sending ACK%s to tun %s/%u seq %u ack %u data %u confirm %u",
(fin ? "/FIN" : ""), to, ntohs(tcp->dest),
ntohl(tcp->seq), ntohl(tcp->ack_seq), datalen, confirm);
int res = write(tun, buffer, len);
if (res < 0) {