第12章-Udp服务与客户端

接下来为了让Reactor框架功能更加丰富，结合之前的功能，再加上udpserver的服务接口。udp我们暂时不考虑加线程池实现，只是单线程的处理方式。

12.1 udp_server服务端功能实现

lars_reactor/include/udp_server.h

#pragma  once
#include <netinet/in.h>
#include "event_loop.h"
#include "net_connection.h"
#include "message.h"
class udp_server :public net_connection 
{
public:
    udp_server(event_loop *loop, const char *ip, uint16_t port);
    virtual int send_message(const char *data, int msglen, int msgid);
    //注册消息路由回调函数
    void add_msg_router(int msgid, msg_callback* cb, void *user_data = NULL);
    ~udp_server();
    //处理消息业务
    void do_read();
private:
    int _sockfd;
    char _read_buf[MESSAGE_LENGTH_LIMIT];
    char _write_buf[MESSAGE_LENGTH_LIMIT];
    //事件触发
    event_loop* _loop;
    //服务端ip
    struct sockaddr_in _client_addr;
    socklen_t _client_addrlen;
    //消息路由分发
    msg_router _router;
};

    对应的方法实现方式如下：

lars_reactor/src/udp_server.cpp

#include <signal.h>
#include <unistd.h>
#include <strings.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdio.h>
#include <string.h>
#include "udp_server.h"
void read_callback(event_loop *loop, int fd, void *args)
{
    udp_server *server = (udp_server*)args;
    //处理业务函数
    server->do_read();
}
void udp_server::do_read()
{
    while (true) {
        int pkg_len = recvfrom(_sockfd, _read_buf, sizeof(_read_buf), 0, (struct sockaddr *)&_client_addr, &_client_addrlen);
        if (pkg_len == -1) {
            if (errno == EINTR) {
                continue;
            }
            else if (errno == EAGAIN) {
                break;
            }
            else {
                perror("recvfrom\n");
                break;
            }
        }
        //处理数据
        msg_head head; 
        memcpy(&head, _read_buf, MESSAGE_HEAD_LEN);
        if (head.msglen > MESSAGE_LENGTH_LIMIT || head.msglen < 0 || head.msglen + MESSAGE_HEAD_LEN != pkg_len) {
            //报文格式有问题
            fprintf(stderr, "do_read, data error, msgid = %d, msglen = %d, pkg_len = %d\n", head.msgid, head.msglen, pkg_len);
            continue;
        }
        //调用注册的路由业务
        _router.call(head.msgid, head.msglen, _read_buf+MESSAGE_HEAD_LEN, this);
    }
}
udp_server::udp_server(event_loop *loop, const char *ip, uint16_t port)
{
    //1 忽略一些信号
    if (signal(SIGHUP, SIG_IGN) == SIG_ERR) {
        perror("signal ignore SIGHUB");
        exit(1);
    }
    if (signal(SIGPIPE, SIG_IGN) == SIG_ERR) {
        perror("signal ignore SIGPIPE");
        exit(1);
    }
    //2 创建套接字
    //SOCK_CLOEXEC在execl中使用该socket则关闭，在fork中使用该socket不关闭
    _sockfd = socket(AF_INET, SOCK_DGRAM | SOCK_NONBLOCK | SOCK_CLOEXEC, IPPROTO_UDP);
    if (_sockfd == -1) {
        perror("create udp socket");
        exit(1);
    }
    //3 设置服务ip+port
    struct sockaddr_in servaddr;
    bzero(&servaddr, sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    inet_aton(ip, &servaddr.sin_addr);//设置ip
    servaddr.sin_port = htons(port);//设置端口
    //4 绑定
    bind(_sockfd, (const struct sockaddr*)&servaddr, sizeof(servaddr));
    //3 添加读业务事件
    _loop = loop;
    bzero(&_client_addr, sizeof(_client_addr));
    _client_addrlen = sizeof(_client_addr);
    printf("server on %s:%u is running...\n", ip, port);
    _loop->add_io_event(_sockfd, read_callback, EPOLLIN, this);
}
int udp_server::send_message(const char *data, int msglen, int msgid)
{
    if (msglen > MESSAGE_LENGTH_LIMIT) {
        fprintf(stderr, "too large message to send\n");
        return -1;
    }
    msg_head head;
    head.msglen = msglen;
    head.msgid = msgid;
    memcpy(_write_buf,  &head, MESSAGE_HEAD_LEN);
    memcpy(_write_buf + MESSAGE_HEAD_LEN, data, msglen);
    int ret = sendto(_sockfd, _write_buf, msglen + MESSAGE_HEAD_LEN, 0, (struct sockaddr*)&_client_addr, _client_addrlen);
    if (ret == -1) {
        perror("sendto()..");
        return -1;
    }
    return ret;
}
//注册消息路由回调函数
void udp_server::add_msg_router(int msgid, msg_callback* cb, void *user_data)
{
    _router.register_msg_router(msgid, cb, user_data);
}
udp_server::~udp_server()
{
    _loop->del_io_event(_sockfd);
    close(_sockfd);
}

这里面实现的方式和tcp_server的实现方式几乎一样，需要注意的是，udp的socket编程是不需要listen的，而且也不需要accept。所以recvfrom就能够得知每个包的对应客户端是谁，然后回执消息给对应的客户端就可以。因为没有连接，所以都是以包为单位来处理的，一个包一个包处理。可能相邻的两个包来自不同的客户端。

12.2 udp_client客户端功能实现

lars_reactor/include/udp_client.h

#pragma once
#include "net_connection.h"
#include "message.h"
#include "event_loop.h"
class udp_client: public net_connection
{
public:
    udp_client(event_loop *loop, const char *ip, uint16_t port);
    ~udp_client();
    void add_msg_router(int msgid, msg_callback *cb, void *user_data = NULL);
    virtual int send_message(const char *data, int msglen, int msgid);
    //处理消息
    void do_read();
private:
    int _sockfd;
    char _read_buf[MESSAGE_LENGTH_LIMIT];
    char _write_buf[MESSAGE_LENGTH_LIMIT];
    //事件触发
    event_loop *_loop;
    //消息路由分发
    msg_router _router;
};

lars_reactor/src/udp_client.cpp

#include "udp_client.h"
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <strings.h>
#include <string.h>
#include <stdio.h>
void read_callback(event_loop *loop, int fd, void *args)
{
    udp_client *client = (udp_client*)args;
    client->do_read();
}
udp_client::udp_client(event_loop *loop, const char *ip, uint16_t port)
{
    //1 创建套接字
    _sockfd = socket(AF_INET, SOCK_DGRAM | SOCK_NONBLOCK | SOCK_CLOEXEC, IPPROTO_UDP);
    if (_sockfd == -1) {
        perror("create socket error");
        exit(1);
    }
    struct sockaddr_in servaddr;
    bzero(&servaddr, sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    inet_aton(ip, &servaddr.sin_addr);
    servaddr.sin_port = htons(port);
    //2 链接
    int ret = connect(_sockfd, (const struct sockaddr*)&servaddr, sizeof(servaddr));
    if (ret  == -1) {
        perror("connect");
        exit(1);
    }
    //3 添加读事件
    _loop = loop; 
    _loop->add_io_event(_sockfd, read_callback, EPOLLIN, this);
}
udp_client::~udp_client()
{
    _loop->del_io_event(_sockfd);
    close(_sockfd);
}
//处理消息
void udp_client::do_read()
{
    while (true) {
        int pkt_len = recvfrom(_sockfd, _read_buf, sizeof(_read_buf), 0, NULL, NULL);
        if (pkt_len == -1) {
            if (errno == EINTR) {
                continue;
            }
            else if (errno == EAGAIN) {
                break;
            }
            else {
                perror("recvfrom()");
                break;
            }
        }
        //处理客户端包
        msg_head head; 
        memcpy(&head, _read_buf, MESSAGE_HEAD_LEN);
        if (head.msglen > MESSAGE_LENGTH_LIMIT || head.msglen < 0 || head.msglen + MESSAGE_HEAD_LEN != pkt_len) {
            //报文格式有问题
            fprintf(stderr, "do_read, data error, msgid = %d, msglen = %d, pkt_len = %d\n", head.msgid, head.msglen, pkt_len);
            continue;
        }
        //调用注册的路由业务
        _router.call(head.msgid, head.msglen, _read_buf+MESSAGE_HEAD_LEN, this);
    }
}
void udp_client::add_msg_router(int msgid, msg_callback *cb, void *user_data)
{
    _router.register_msg_router(msgid, cb, user_data);
}
int udp_client::send_message(const char *data, int msglen, int msgid)
{
    if (msglen > MESSAGE_LENGTH_LIMIT) {
        fprintf(stderr, "too large message to send\n");
        return -1;
    }
    msg_head head;
    head.msglen = msglen;
    head.msgid = msgid;
    memcpy(_write_buf,  &head, MESSAGE_HEAD_LEN);
    memcpy(_write_buf + MESSAGE_HEAD_LEN, data, msglen);
    int ret = sendto(_sockfd, _write_buf, msglen + MESSAGE_HEAD_LEN, 0, NULL, 0);
    if (ret == -1) {
        perror("sendto()..");
        return -1;
    }
    return ret;
}

    客户端和服务端代码除了构造函数不同，其他基本差不多。接下来我们可以测试一下udp的通信功能

12.3 完成Lars Reactor V0.10开发

服务端

server.cpp

#include <string>
#include <string.h>
#include "config_file.h"
#include "udp_server.h"
//回显业务的回调函数
void callback_busi(const char *data, uint32_t len, int msgid, net_connection *conn, void *user_data)
{
    printf("callback_busi ...\n");
    //直接回显
    conn->send_message(data, len, msgid);
}
int main() 
{
    event_loop loop;
    //加载配置文件
    config_file::setPath("./serv.conf");
    std::string ip = config_file::instance()->GetString("reactor", "ip", "0.0.0.0");
    short port = config_file::instance()->GetNumber("reactor", "port", 8888);
    printf("ip = %s, port = %d\n", ip.c_str(), port);
    udp_server server(&loop, ip.c_str(), port);
    //注册消息业务路由
    server.add_msg_router(1, callback_busi);
    loop.event_process();
    return 0;
}

客户端

client.cpp

#include <stdio.h>
#include <string.h>
#include "udp_client.h"
//客户端业务
void busi(const char *data, uint32_t len, int msgid, net_connection  *conn, void *user_data)
{
    //得到服务端回执的数据 
    char *str = NULL;
    str = (char*)malloc(len+1);
    memset(str, 0, len+1);
    memcpy(str, data, len);
    printf("recv server: [%s]\n", str);
    printf("msgid: [%d]\n", msgid);
    printf("len: [%d]\n", len);
}
int main() 
{
    event_loop loop;
    //创建udp客户端
    udp_client client(&loop, "127.0.0.1", 7777);
    //注册消息路由业务
    client.add_msg_router(1, busi);
    //发消息
    int msgid = 1; 
    const char *msg = "Hello Lars!";
    client.send_message(msg, strlen(msg), msgid);
    //开启事件监听
    loop.event_process();
    return 0;
}

启动服务端和客户端并允许，结果如下：

server

$ ./server 
ip = 127.0.0.1, port = 7777
msg_router init...
server on 127.0.0.1:7777 is running...
add msg cb msgid = 1
call msgid = 1
call data = Hello Lars!
call msglen = 11
callback_busi ...
=======

client

$ ./client 
msg_router init...
add msg cb msgid = 1
call msgid = 1
call data = Hello Lars!
call msglen = 11
recv server: [Hello Lars!]
msgid: [1]
len: [11]
=======