208 lines
9.5 KiB
Python
208 lines
9.5 KiB
Python
#!/usr/bin/env python
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# -*- coding: utf-8 -*-
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"""
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LoRa模块的具体实现 (UART Passthrough for LoRa Mesh)
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负责与LoRa模块进行底层通信，并向上层提供标准化的数据包收发接口。
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这个实现针对的是通过UART进行透传的LoRa Mesh模块。
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"""
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from ..logs.logger import log
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from machine import UART
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import time
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class LoRaMeshUartPassthroughManager:
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"""
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通过UART与LoRa Mesh模块通信的处理器实现 (ED模式)。
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实现了自动分片与重组逻辑。
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"""
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def __init__(self, lora_config: dict):
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"""
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初始化LoRa处理器。
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Args:
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lora_config (dict): 来自全局配置文件的LoRa配置字典。
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"""
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log("LoRaMeshUartPassthroughManager: 初始化...")
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# --- 配置注入 ---
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self.master_address = lora_config.get('master_address')
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self.uart_id = lora_config.get('uart_id')
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self.baudrate = lora_config.get('baudrate')
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self.pins = lora_config.get('pins')
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self.max_chunk_size = lora_config.get('max_chunk_size')
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self.lora_mesh_mode = b'\xed'
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# TODO 目前这个配置没用, 完全按ED处理的
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if lora_config.get('lora_mesh_mode') == 'EC':
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self.lora_mesh_mode = b'\xec'
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# --- 硬件初始化 ---
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self.uart = UART(self.uart_id, self.baudrate, tx=self.pins['tx'], rx=self.pins['rx'])
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# --- 内部状态变量 ---
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self._rx_buffer = bytearray() # UART接收缓冲区
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self._reassembly_cache = {} # 分片重组缓冲区 { chunk_index: chunk_data }
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self._expected_chunks = 0 # 当前会话期望的总分片数
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log(f"LoRaMeshUartPassthroughManager: 配置加载完成. UART ID: {self.uart_id}, Baudrate: {self.baudrate}, 针脚: {self.pins}")
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def send_packet(self, payload: bytes) -> bool:
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"""
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【实现】发送一个数据包，自动处理分片。
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Args:
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payload (bytes): 需要发送的完整业务数据。
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Returns:
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bool: True表示所有分片都已成功提交发送，False表示失败。
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"""
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max_chunk_size = self.max_chunk_size
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if not payload:
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total_chunks = 1
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else:
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total_chunks = (len(payload) + max_chunk_size - 1) // max_chunk_size
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try:
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for i in range(total_chunks):
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chunk_index = i
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start = i * max_chunk_size
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end = start + max_chunk_size
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chunk_data = payload[start:end]
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# --- 组装物理包 ---
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header = b'\xed'
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dest_addr_bytes = self.master_address.to_bytes(2, 'big')
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total_chunks_bytes = total_chunks.to_bytes(1, 'big')
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current_chunk_bytes = chunk_index.to_bytes(1, 'big')
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# 计算后续长度(总包数和当前包序号是自定义包头, 各占一位, 标准包头算在长度内)
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length_val = 2 + len(chunk_data)
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length_bytes = length_val.to_bytes(1, 'big')
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# 拼接成最终的数据包
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packet_to_send = header + length_bytes + dest_addr_bytes + total_chunks_bytes + current_chunk_bytes + chunk_data
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self.uart.write(packet_to_send)
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log(f"LoRa: 发送分片 {chunk_index + 1}/{total_chunks} 到地址 {self.master_address}")
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# 让出CPU, 模块将缓存区的数据发出去本身也需要时间
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time.sleep_ms(10)
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return True
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except Exception as e:
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log(f"LoRa: 发送数据包失败: {e}")
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return False
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def receive_packet(self) -> bytes | None:
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"""
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【实现】非阻塞地检查、解析并重组一个完整的数据包。
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"""
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# 1. 从硬件读取数据到缓冲区
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if self.uart.any():
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new_data = self.uart.read()
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if new_data:
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log(f"LoRa: UART收到原始数据 (长度 {len(new_data)}): {new_data.hex()}")
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self._rx_buffer.extend(new_data)
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# 如果缓冲区为空，没有必要继续处理
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if not self._rx_buffer:
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return None
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# 2. 只要缓冲区有数据就持续尝试从缓冲区解析包
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while len(self._rx_buffer) > 0:
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log(f"LoRa: --- 开始新一轮解析, 缓冲区 (长度 {len(self._rx_buffer)}): {self._rx_buffer.hex()} ---")
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# 2.1 检查头部和长度字段是否存在
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if len(self._rx_buffer) < 2:
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log("LoRa: 缓冲区数据不足 (小于2字节)，无法读取包头。等待更多数据...")
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return None # 数据不足，无法读取长度
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# 2.2 检查帧头是否正确
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if self._rx_buffer[0] != 0xED:
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log(f"LoRa: 接收到错误帧头: {hex(self._rx_buffer[0])}，正在寻找下一个ED...")
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next_ed = self._rx_buffer.find(b'\xed', 1)
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if next_ed == -1:
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log("LoRa: 缓冲区无有效帧头，已清空。")
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self._rx_buffer[:] = b''
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return None # 清空后没有数据了, 直接返回
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else:
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log(f"LoRa: 在位置 {next_ed} 找到下一个有效帧头，丢弃之前的数据。")
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self._rx_buffer = self._rx_buffer[next_ed:]
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continue # 继续循环，用新的缓冲区数据重新开始解析
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# 2.3 检查包是否完整
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payload_len = self._rx_buffer[1]
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# 这里的 total_packet_len 计算方式存疑，它假设 payload_len 是 length 字段之后所有数据的长度。
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# 这与 send_packet 中的 length 计算方式可能不一致。
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total_packet_len = 1 + 1 + payload_len
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log(f"LoRa: 帧头正确(ED)。声明的后续包长(payload_len): {payload_len}。计算出的总包长: {total_packet_len}。")
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if len(self._rx_buffer) < total_packet_len:
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log(f"LoRa: '半包'情况，需要 {total_packet_len} 字节，但缓冲区只有 {len(self._rx_buffer)} 字节。等待更多数据...")
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return None # "半包"情况，等待更多数据
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# 3. 提取和解析一个完整的物理包
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log(f"LoRa: 发现完整物理包 (长度 {total_packet_len})，正在提取...")
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packet = self._rx_buffer[:total_packet_len]
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self._rx_buffer = self._rx_buffer[total_packet_len:]
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log(f"LoRa: 提取的包: {packet.hex()}。剩余缓冲区 (长度 {len(self._rx_buffer)}): {self._rx_buffer.hex()}")
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# --- 包结构解析 ---
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# 根据代码 `chunk_data = packet[6:-2]` 推断，包结构为:
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# 1 (帧头) + 1 (长度) + 2 (目标地址) + 1 (总分片) + 1 (当前分片) + N (数据) + 2 (源地址)
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# 因此，一个合法的包至少需要 1+1+2+1+1+2 = 8个字节
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if len(packet) < 8:
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log(f"LoRa: 包长度 {len(packet)} 小于协议最小长度8, 判定为坏包，已丢弃。")
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continue
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addr = int.from_bytes(packet[2:4], 'big')
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total_chunks = packet[4]
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current_chunk = packet[5]
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# 提取数据块，排除末尾的2字节源地址
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chunk_data = packet[6:-2]
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source_addr = int.from_bytes(packet[-2:], 'big')
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log(f"LoRa: 解析包: 源地址={source_addr}, 目标地址={addr}, 总分片={total_chunks}, 当前分片={current_chunk}, 数据块长度={len(chunk_data)}")
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# 4. 重组逻辑
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if total_chunks == 1:
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log(f"LoRa: 收到单包消息，来自地址 {source_addr}，长度 {len(chunk_data)}")
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self._reassembly_cache.clear()
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self._expected_chunks = 0
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return chunk_data
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# 对于多包消息，只有当收到第一个分片时才清空缓存并设置期望分片数
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if current_chunk == 0:
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log(f"LoRa: 开始接收新的多包会话 ({total_chunks}个分片) from {source_addr}...")
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self._reassembly_cache.clear()
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self._expected_chunks = total_chunks
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elif not self._reassembly_cache and self._expected_chunks == 0:
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# 如果不是第一个分片，但缓存是空的，说明错过了第一个分片，丢弃当前分片
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log(f"LoRa: 收到非首个分片 {current_chunk} from {source_addr}，但未检测到会话开始，已丢弃。")
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continue
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self._reassembly_cache[current_chunk] = chunk_data
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log(f"LoRa: 收到分片 {current_chunk + 1}/{self._expected_chunks} from {source_addr}，已缓存 {len(self._reassembly_cache)} 个")
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if len(self._reassembly_cache) == self._expected_chunks:
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log(f"LoRa: 所有分片已集齐 (from {source_addr})，正在重组...")
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full_payload = bytearray()
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for i in range(self._expected_chunks):
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if i not in self._reassembly_cache:
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log(f"LoRa: 重组失败！缺少分片 {i}。")
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self._reassembly_cache.clear()
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self._expected_chunks = 0
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return None
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full_payload.extend(self._reassembly_cache[i])
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log(f"LoRa: 重组完成，总长度 {len(full_payload)}")
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self._reassembly_cache.clear()
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self._expected_chunks = 0
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return bytes(full_payload)
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# while 循环结束，意味着缓冲区被处理完毕但没有返回一个完整的包
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return None
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