引言&协议概述

中国电信短消息网关协议（SMGP）是中国网通为实现短信业务而制定的一种通信协议，全称叫做Short Message Gateway Protocol，用于在短消息网关（SMGW）和服务提供商（SP）之间、短消息网关（SMGW）和短消息网关（SMGW）之间通信。

Perl是一个老牌脚本语言，在众多Linux系统上都会默认安装，比如在ubuntu的22.04版本的基础镜像中，甚至没有Python，但是依然安装了Perl，Perl的普及度可见一斑。Perl的IO::Async模块提供了一套简洁的异步IO编程模型。

SMGP 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）先和短信网关（SMGW Short Message Gateway）建立起 TCP 长连接，并使用 CNGP 命令与SMGW进行交互，实现短信的发送和接收。在CNGP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

连接成功，发送短信

连接成功，从SMGW接收到短信

协议帧介绍

SMGP Header

Header包含以下字段，大小长度都是4字节

• Packet Length：整个PDU的长度，包括Header和Body。
• Request ID：用于标识PDU的类型（例如，Login、Submit等）。
• Sequence Id：序列号，用来匹配请求和响应。

使用perl实现SMGP协议栈里的建立连接

├── Makefile.PL
├── examples
│   └── smgp_client_login_example.pl
└── lib
    └── Smgp
        ├── BoundAtomic.pm
        ├── Client.pm
        ├── Constant.pm
        └── Protocol.pm

• Makefile.PL：用来生成Makefile
• examples：存放示例代码
  • smgp_client_login_example.pl：存放Smgp的login样例
• lib/Smgp：包含所有的Perl模块文件
  • BoundAtomic.pm：递增工具类，用来生成SequenceId
  • Client.pm：Smgp定义，负责与Smgp服务进行通信，例如建立连接、发送短信等
  • Protocol.pm：存放PDU，编解码等

实现sequence_id递增

sequence_id是从1到0x7FFFFFFF的值

package Smgp::BoundAtomic;

use strict;
use warnings FATAL => 'all';

sub new {
    my ($class, %args) = @_;
    my $self = {
        min     => $args{min},
        max     => $args{max},
        value   => $args{min},
    };
    bless $self, $class;
    return $self;
}

sub increment {
    my ($self) = @_;
    if ($self->{value} >= $self->{max}) {
        $self->{value} = $self->{min};
    } else {
        $self->{value}++;
    }
    return $self->{value};
}

sub get {
    my ($self) = @_;
    return $self->{value};
}

1;

在Perl中定义SMGP PDU以及编解码函数

package Smgp::Protocol;

use strict;
use warnings FATAL => 'all';

use Smgp::Constant;

sub new_login {
    my ($class, %args) = @_;
    my $self = {
        clientId            => $args{clientId},
        authenticatorClient => $args{authenticatorClient},
        loginMode           => $args{loginMode},
        timeStamp           => $args{timeStamp},
        version             => $args{version},
    };
    return bless $self, $class;
}

sub encode_login {
    my ($self) = @_;
    return pack("A8A16CNC", @{$self}{qw(clientId authenticatorClient loginMode timeStamp version)});
}

sub decode_login_resp {
    my ($class, $buffer) = @_;
    my ($status, $authenticatorServer, $version) = unpack("N4A16C", $buffer);
    return bless {
        status              => $status,
        authenticatorServer => $authenticatorServer,
        version             => $version,
    }, $class;
}

sub new_header {
    my ($class, %args) = @_;
    my $self = {
        total_length   => $args{total_length},
        request_id     => $args{request_id},
        command_status => $args{command_status},
        sequence_id    => $args{sequence_id},
    };
    return bless $self, $class;
}

sub encode_header {
    my ($self, $total_length) = @_;
    return pack("N3", $total_length, @{$self}{qw(request_id sequence_id)});
}

sub new_pdu {
    my ($class, %args) = @_;
    my $self = {
        header => $args{header},
        body   => $args{body},
    };
    return bless $self, $class;
}

sub encode_login_pdu {
    my ($self) = @_;
    my $encoded_body = $self->{body}->encode_login();
    return $self->{header}->encode_header(length($encoded_body) + 12) . $encoded_body;
}

sub decode_pdu {
    my ($class, $buffer) = @_;
    my ($request_id, $sequence_id) = unpack("N2", substr($buffer, 0, 8));
    my $body_buffer = substr($buffer, 8);

    my $header = $class->new_header(
        total_length   => 0,
        request_id     => $request_id,
        sequence_id    => $sequence_id,
    );

    my $body;
    if ($request_id == Smgp::Constant::LOGIN_RESP_ID) {
        $body = $class->decode_login_resp($body_buffer);
    } else {
        die "Unsupported request_id: $request_id";
    }

    return $class->new_pdu(
        header => $header,
        body   => $body,
    );
}

1;

constant.pm存放相关requestId

package Smgp::Constant;

use strict;
use warnings FATAL => 'all';

use constant {
    LOGIN_ID               => 0x00000001,
    LOGIN_RESP_ID          => 0x80000001,
    SUBMIT_ID              => 0x00000002,
    SUBMIT_RESP_ID         => 0x80000002,
    DELIVER_ID             => 0x00000003,
    DELIVER_RESP_ID        => 0x80000003,
    ACTIVE_TEST_ID         => 0x00000004,
    ACTIVE_TEST_RESP_ID    => 0x80000004,
    FORWARD_ID             => 0x00000005,
    FORWARD_RESP_ID        => 0x80000005,
    EXIT_ID                => 0x00000006,
    EXIT_RESP_ID           => 0x80000006,
    QUERY_ID               => 0x00000007,
    QUERY_RESP_ID          => 0x80000007,
    MT_ROUTE_UPDATE_ID     => 0x00000008,
    MT_ROUTE_UPDATE_RESP_ID => 0x80000008,
};

1;

实现client以及login方法

package Smgp::Client;
use strict;
use warnings FATAL => 'all';
use IO::Socket::INET;

use Smgp::Protocol;
use Smgp::Constant;

sub new {
    my ($class, %args) = @_;
    my $self = {
        host => $args{host} // 'localhost',
        port => $args{port} // 9000,
        socket => undef,
        sequence_id => 1,
    };
    bless $self, $class;
    return $self;
}

sub connect {
    my ($self) = @_;
    $self->{socket} = IO::Socket::INET->new(
        PeerHost => $self->{host},
        PeerPort => $self->{port},
        Proto => 'tcp',
    ) or die "Cannot connect to $self->{host}:$self->{port} $!";
}

sub login {
    my ($self, $body) = @_;
    my $header = Smgp::Protocol->new_header(
        request_id     => Smgp::Constant::LOGIN_ID,
        sequence_id    => 1,
    );

    my $pdu = Smgp::Protocol->new_pdu(
        header => $header,
        body   => $body,
    );

    $self->{socket}->send($pdu->encode_login_pdu());

    $self->{socket}->recv(my $response_length_bytes, 4);

    my $total_length = unpack("N", $response_length_bytes);
    my $remain_length = $total_length - 4;
    $self->{socket}->recv(my $response_data, $remain_length);

    return Smgp::Protocol->decode_pdu($response_data)->{body};
}

sub disconnect {
    my ($self) = @_;
    close($self->{socket}) if $self->{socket};
}

1;

运行example，验证连接成功

package smgp_client_login_example;

use strict;
use warnings FATAL => 'all';

use Smgp::Client;
use Smgp::Protocol;
use Smgp::Constant;

sub main {
    my $client = Smgp::Client->new(
        host => 'localhost',
        port => 9000,
    );

    $client->connect();

    my $login = Smgp::Protocol->new_login(
        clientId            => '12345678',
        authenticatorClient => '1234567890123456',
        loginMode           => 1,
        timeStamp           => time(),
        version             => 0,
    );

    my $response = $client->login($login);

    if ($response->{status} == 0) {
        print "Login successful!\n";
    }
    else {
        print "Login failed! Status: ", (defined $response->{status} ? $response->{status} : 'undefined'), "\n";
    }

    $client->disconnect();
}

main() unless caller;

1;

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
• cmpp-python cmpp协议的python实现
• cngp-zig cmpp协议的python实现
• smgp-perl smgp协议的perl实现
• smpp-rust smpp协议的rust实现

总结

本文简单对SMGP协议进行了介绍，并尝试用perl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）服务通过HTTP协议接入，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。