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教你用Rust实现Smpp协议
作者:mmseoamin日期:2024-02-22

本文分享自华为云社区《华为云短信服务教你用Rust实现Smpp协议》,作者: 张俭。

协议概述

SMPP(Short Message Peer-to-Peer)协议起源于90年代,最初由Aldiscon公司开发,后来由SMPP开发者论坛维护和推广。SMPP常用于在SMSC(Short Message Service Center,短信中心)和短信应用之间传输短消息,支持高效的短信息发送、接收和查询功能,是电信运营商和短信服务提供商之间互通短信的主要协议之一。

SMPP协议基于客户端/服务端模型工作。由客户端(短信应用,如手机,应用程序等)先和SMSC建立起TCP长连接,并使用SMPP命令与SMSC进行交互,实现短信的发送和接收。在SMPP协议中,无需同步等待响应就可以发送下一个指令,实现者可以根据自己的需要,实现同步、异步两种消息传输模式,满足不同场景下的性能要求。

时序图

绑定transmitter模式,发送短信并查询短信发送成功

教你用Rust实现Smpp协议,cke_127.png,第1张

绑定receiver模式,从SMSC接收到短信

教你用Rust实现Smpp协议,cke_128.png,第2张

协议帧介绍

教你用Rust实现Smpp协议,cke_129.png,第3张

在SMPP协议中,每个PDU都包含两个部分:SMPP Header和SMPP Body。

SMPP Header

Header包含以下字段,大小长度都是4字节

  • Command Length:整个PDU的长度,包括Header和Body。
  • Command ID:用于标识PDU的类型(例如,BindReceiver、QuerySM等)。
  • Command Status:响应状态码,表示处理的结果。
  • Sequence Number:序列号,用来匹配请求和响应。

    用Rust实现SMPP协议栈里的BindTransmitter

    本文的代码均已上传到smpp-rust

    选用Tokio作为基础的异步运行时环境,tokio有非常强大的异步IO支持,也是rust库的事实标准。

    代码结构组织如下:

    ├── lib.rs
    ├── const.rs
    ├── protocol.rs
    ├── smpp_client.rs
    └── smpp_server.rs
    • lib.rs Rust项目的入口点
    • const.rs 包含常量定义,如commandId、状态码等
    • protocol.rs 包含PDU定义,编解码处理等
    • smpp_client.rs 实现smpp客户端逻辑
    • smpp_server.rs 实现

      利用rust原子类实现sequence_number

      sequence_number是从1到0x7FFFFFFF的值,利用Rust的AtomicI32来生成这个值。

      use std::sync::atomic::{AtomicI32, Ordering};
      use std::num::TryFromIntError;
      struct BoundAtomicInt {
      min: i32,
      max: i32,
      integer: AtomicI32,
      }
      impl BoundAtomicInt {
      pub fn new(min: i32, max: i32) -> Self {
      assert!(min <= max, "min must be less than or equal to max");
      Self {
      min,
      max,
      integer: AtomicI32::new(min),
      }
      }
      pub fn next_val(&self) -> Result {
      let next = self.integer.fetch_update(Ordering::SeqCst, Ordering::SeqCst, |x| {
      Some(if x >= self.max { self.min } else { x + 1 })
      })?;
      Ok(next)
      }
      }

      在Rust中定义SMPP PDU

      pub struct SmppPdu {
      pub header: SmppHeader,
      pub body: SmppBody,
      }
      pub struct SmppHeader {
      pub command_length: i32,
      pub command_id: i32,
      pub command_status: i32,
      pub sequence_number: i32,
      }
      pub enum SmppBody {
      BindReceiver(BindReceiver),
      BindReceiverResp(BindReceiverResp),
      BindTransmitter(BindTransmitter),
      BindTransmitterResp(BindTransmitterResp),
      QuerySm(QuerySm),
      QuerySmResp(QuerySmResp),
      SubmitSm(SubmitSm),
      SubmitSmResp(SubmitSmResp),
      DeliverSm(DeliverSm),
      DeliverSmResp(DeliverSmResp),
      Unbind(Unbind),
      UnbindResp(UnbindResp),
      ReplaceSm(ReplaceSm),
      ReplaceSmResp(ReplaceSmResp),
      CancelSm(CancelSm),
      CancelSmResp(CancelSmResp),
      BindTransceiver(BindTransceiver),
      BindTransceiverResp(BindTransceiverResp),
      Outbind(Outbind),
      EnquireLink(EnquireLink),
      EnquireLinkResp(EnquireLinkResp),
      SubmitMulti(SubmitMulti),
      SubmitMultiResp(SubmitMultiResp),
      }

      实现编解码方法

      impl SmppPdu {
      pub fn encode(&self) -> Vec {
      let mut body_buf = match &self.body {
      SmppBody::BindTransmitter(bind_transmitter) => bind_transmitter.encode(),
      _ => unimplemented!(),
      };
      let command_length = (body_buf.len() + 16) as i32;
      let header = SmppHeader {
      command_length,
      command_id: self.header.command_id,
      command_status: self.header.command_status,
      sequence_number: self.header.sequence_number,
      };
      let mut buf = header.encode();
      buf.append(&mut body_buf);
      buf
      }
      pub fn decode(buf: &[u8]) -> io::Result {
      let header = SmppHeader::decode(&buf[0..16])?;
      let body = match header.command_id {
      constant::BIND_TRANSMITTER_RESP_ID => SmppBody::BindTransmitterResp(BindTransmitterResp::decode(&buf[16..])?),
      _ => unimplemented!(),
      };
      Ok(SmppPdu { header, body })
      }
      }
      impl SmppHeader {
      pub(crate) fn encode(&self) -> Vec {
      let mut buf = vec![];
      buf.extend_from_slice(&self.command_length.to_be_bytes());
      buf.extend_from_slice(&self.command_id.to_be_bytes());
      buf.extend_from_slice(&self.command_status.to_be_bytes());
      buf.extend_from_slice(&self.sequence_number.to_be_bytes());
      buf
      }
      pub(crate) fn decode(buf: &[u8]) -> io::Result {
      if buf.len() < 16 {
      return Err(io::Error::new(io::ErrorKind::InvalidData, "Buffer too short for SmppHeader"));
      }
      let command_id = u32::from_be_bytes(buf[0..4].try_into().unwrap());
      let command_status = i32::from_be_bytes(buf[4..8].try_into().unwrap());
      let sequence_number = i32::from_be_bytes(buf[8..12].try_into().unwrap());
      Ok(SmppHeader {
      command_length: 0,
      command_id,
      command_status,
      sequence_number,
      })
      }
      }
      impl BindTransmitter {
      pub(crate) fn encode(&self) -> Vec {
      let mut buf = vec![];
      write_cstring(&mut buf, &self.system_id);
      write_cstring(&mut buf, &self.password);
      write_cstring(&mut buf, &self.system_type);
      buf.push(self.interface_version);
      buf.push(self.addr_ton);
      buf.push(self.addr_npi);
      write_cstring(&mut buf, &self.address_range);
      buf
      }
      pub(crate) fn decode(buf: &[u8]) -> io::Result {
      let mut offset = 0;
      let system_id = read_cstring(buf, &mut offset)?;
      let password = read_cstring(buf, &mut offset)?;
      let system_type = read_cstring(buf, &mut offset)?;
      let interface_version = buf[offset];
      offset += 1;
      let addr_ton = buf[offset];
      offset += 1;
      let addr_npi = buf[offset];
      offset += 1;
      let address_range = read_cstring(buf, &mut offset)?;
      Ok(BindTransmitter {
      system_id,
      password,
      system_type,
      interface_version,
      addr_ton,
      addr_npi,
      address_range,
      })
      }
      }

      实现同步的bind_transmitter方法

      pub async fn bind_transmitter(
      &mut self,
      bind_transmitter: BindTransmitter,
      ) -> io::Result {
      if let Some(stream) = &mut self.stream {
      let sequence_number = self.sequence_number.next_val();
      let pdu = SmppPdu {
      header: SmppHeader {
      command_length: 0,
      command_id: constant::BIND_TRANSMITTER_ID,
      command_status: 0,
      sequence_number,
      },
      body: SmppBody::BindTransmitter(bind_transmitter),
      };
      let encoded_request = pdu.encode();
      stream.write_all(&encoded_request).await?;
      let mut length_buf = [0u8; 4];
      stream.read_exact(&mut length_buf).await?;
      let msg_length = u32::from_be_bytes(length_buf) as usize - 4;
      let mut msg_buf = vec![0u8; msg_length];
      stream.read_exact(&mut msg_buf).await?;
      let response = SmppPdu::decode(&msg_buf)?;
      if response.header.command_status != 0 {
      Err(io::Error::new(
      io::ErrorKind::Other,
      format!("Error response: {:?}", response.header.command_status),
      ))
      } else {
      // Assuming response.body is of type BindTransmitterResp
      match response.body {
      SmppBody::BindTransmitterResp(resp) => Ok(resp),
      _ => Err(io::Error::new(io::ErrorKind::InvalidData, "Unexpected response body")),
      }
      }
      } else {
      Err(io::Error::new(io::ErrorKind::NotConnected, "Not connected"))
      }
      }

      运行example,验证连接成功

      use smpp_rust::protocol::BindTransmitter;
      use smpp_rust::smpp_client::SmppClient;
      #[tokio::main]
      async fn main() -> Result<(), Box> {
      let mut client = SmppClient::new("127.0.0.1", 2775);
      client.connect().await?;
      let bind_transmitter = BindTransmitter{
      system_id: "system_id".to_string(),
      password: "password".to_string(),
      system_type: "system_type".to_string(),
      interface_version: 0x34,
      addr_ton: 0,
      addr_npi: 0,
      address_range: "".to_string(),
      };
      client.bind_transmitter(bind_transmitter).await?;
      client.close().await?;
      Ok(())
      }

      教你用Rust实现Smpp协议,cke_130.png,第4张

      相关开源项目

      • netty-codec-sms 存放各种SMS协议(如cmpp、sgip、smpp)的netty编解码器
      • sms-client-java 存放各种SMS协议的Java客户端
      • sms-server-java 存放各种SMS协议的Java服务端
      • smpp-rust smpp协议的rust实现

        总结

        本文简单对SMPP协议进行了介绍,并尝试用rust实现协议栈,但实际商用发送短信往往更加复杂,面临诸如流控、运营商对接、传输层安全等问题,可以选择华为云消息&短信(Message & SMS)服务,华为云短信服务是华为云携手全球多家优质运营商和渠道,为企业用户提供的通信服务。企业调用API或使用群发助手,即可使用验证码、通知短信服务。

        点击关注,第一时间了解华为云新鲜技术~