教你用Rust实现Smpp协议

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

绑定receiver模式，从SMSC接收到短信

协议帧介绍

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<i32, TryFromIntError> {

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<u8> {

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<Self> {

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<u8> {

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<Self> {

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<u8> {

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<Self> {

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<BindTransmitterResp> {

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<dyn std::error::Error>> {

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(())

}

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。

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