Fix: ACK section length calculation and increase socket buffers

src/etcp.c

@@ -747,15 +747,16 @@ void etcp_conn_input(struct ETCP_DGRAM* pkt) {
             case ETCP_SECTION_ACK: {
                 int elm_cnt=data[1];
                 uint32_t till=data[2] | (data[3]<<8) | (data[4]<<16) | (data[5]<<24);
-                data+=6;
+                int ack_section_len = 6 + elm_cnt * 8;
+                data+=ack_section_len;
+                len-=ack_section_len;
                 for (int i=0; i<elm_cnt; i++) {
-                    uint32_t seq=data[0] | (data[1]<<8) | (data[2]<<16) | (data[3]<<24);
+                    uint32_t seq=data[-ack_section_len+6+i*8] | (data[-ack_section_len+7+i*8]<<8) | (data[-ack_section_len+8+i*8]<<16) | (data[-ack_section_len+9+i*8]<<24);
-                    uint16_t ts=data[4] | (data[5]<<8);
+                    uint16_t ts=data[-ack_section_len+10+i*8] | (data[-ack_section_len+11+i*8]<<8);
-                    uint16_t dts=data[6] | (data[7]<<8);
+                    uint16_t dts=data[-ack_section_len+12+i*8] | (data[-ack_section_len+13+i*8]<<8);
                     etcp_ack_recv(etcp, seq, ts, dts);
-                    data+=8;
                     }
-                while (etcp->rx_ack_till-till<0) { etcp->rx_ack_till++; etcp_ack_recv(etcp, etcp->rx_ack_till, -1, -1); }// подтверждаем всё по till
+                while ((int32_t)(etcp->rx_ack_till-till)<0) { etcp->rx_ack_till++; etcp_ack_recv(etcp, etcp->rx_ack_till, -1, -1); }// подтверждаем всё по till
                 break;
             }
             case ETCP_SECTION_PAYLOAD: {

src/etcp_connections.c

@@ -275,6 +275,16 @@ struct ETCP_SOCKET* etcp_socket_add(struct UTUN_INSTANCE* instance, struct socka
         DEBUG_WARN(DEBUG_CATEGORY_CONNECTION, "Failed to set SO_REUSEADDR: %s", strerror(errno));
     }
 
+    // Increase socket buffers for high throughput
+    int sndbuf = 4 * 1024 * 1024;  // 4MB send buffer
+    int rcvbuf = 4 * 1024 * 1024;  // 4MB receive buffer
+    if (setsockopt(e_sock->fd, SOL_SOCKET, SO_SNDBUF, &sndbuf, sizeof(sndbuf)) < 0) {
+        DEBUG_WARN(DEBUG_CATEGORY_CONNECTION, "Failed to set SO_SNDBUF: %s", strerror(errno));
+    }
+    if (setsockopt(e_sock->fd, SOL_SOCKET, SO_RCVBUF, &rcvbuf, sizeof(rcvbuf)) < 0) {
+        DEBUG_WARN(DEBUG_CATEGORY_CONNECTION, "Failed to set SO_RCVBUF: %s", strerror(errno));
+    }
+
     int flags = fcntl(e_sock->fd, F_GETFL, 0);
     fcntl(e_sock->fd, F_SETFL, flags | O_NONBLOCK);