#include <sys/types.h>

#include <sys/socket.h>

#include <netinet/in.h>

#include <arpa/inet.h>

#include <assert.h>

#include <stdio.h>

#include <unistd.h>

#include <errno.h>

#include <string.h>

#include <fcntl.h>

#include <stdlib.h>

#include <sys/epoll.h>

#include <pthread.h>

#define MAX_EVENT_NUMBER 1024

#define TCP_BUFFER_SIZE 512

#define UDP_BUFFER_SIZE 1024

int setnonblocking( int fd )

{

    int old_option = fcntl( fd, F_GETFL );

    int new_option = old_option | O_NONBLOCK;

    fcntl( fd, F_SETFL, new_option );

    return old_option;

}

void addfd( int epollfd, int fd )

{

    epoll_event event;

    event.data.fd = fd;

    //event.events = EPOLLIN | EPOLLET;

    event.events = EPOLLIN;

    epoll_ctl( epollfd, EPOLL_CTL_ADD, fd, &event );

    setnonblocking( fd );

}

int main( int argc, char* argv[] )

{

    if( argc <= 2 )

    {

        printf( "usage: %s ip_address port_number\n", basename( argv[0] ) );

        return 1;

    }

    const char* ip = argv[1];

    int port = atoi( argv[2] );

    int ret = 0;

    struct sockaddr_in address;

    bzero( &address, sizeof( address ) );

    address.sin_family = AF_INET;

    inet_pton( AF_INET, ip, &address.sin_addr );

    address.sin_port = htons( port );

    int listenfd = socket( PF_INET, SOCK_STREAM, 0 );

    assert( listenfd >= 0 );

    ret = bind( listenfd, ( struct sockaddr* )&address, sizeof( address ) );//TCP连接文件描写叙述符listenfd和address绑定了

    assert( ret != -1 );

    ret = listen( listenfd, 5 );

    assert( ret != -1 );

    bzero( &address, sizeof( address ) );//清空了address

    address.sin_family = AF_INET;//又一次设置address为udpserver端地址信息

    inet_pton( AF_INET, ip, &address.sin_addr );

    address.sin_port = htons( port );

    int udpfd = socket( PF_INET, SOCK_DGRAM, 0 );

    assert( udpfd >= 0 );

    ret = bind( udpfd, ( struct sockaddr* )&address, sizeof( address ) );//UDP连接文件描写叙述符udpfd和address绑定了

    assert( ret != -1 );

	//同一个端口上绑定了两个不同类型(TCP和UDP)的socket文件描写叙述符

	//创建epoll事件监听模型

    epoll_event events[ MAX_EVENT_NUMBER ];

    int epollfd = epoll_create( 5 );

    assert( epollfd != -1 );

    addfd( epollfd, listenfd );//listenfd和udpfd均注冊到内核注冊表epollfd上

    addfd( epollfd, udpfd );

    while( 1 )

    {

        int number = epoll_wait( epollfd, events, MAX_EVENT_NUMBER, -1 );

        if ( number < 0 )

        {

            printf( "epoll failure\n" );

            break;

        }

        for ( int i = 0; i < number; i++ )

        {

            int sockfd = events[i].data.fd;

            if ( sockfd == listenfd )

            {

                struct sockaddr_in client_address;

                socklen_t client_addrlength = sizeof( client_address );

                int connfd = accept( listenfd, ( struct sockaddr* )&client_address, &client_addrlength );

                addfd( epollfd, connfd );

            }

            else if ( sockfd == udpfd )

            {

                char buf[ UDP_BUFFER_SIZE ];

                memset( buf, '\0', UDP_BUFFER_SIZE );

                struct sockaddr_in client_address;

                socklen_t client_addrlength = sizeof( client_address );

                ret = recvfrom( udpfd, buf, UDP_BUFFER_SIZE-1, 0, ( struct sockaddr* )&client_address, &client_addrlength );

                if( ret > 0 )

                {

                    sendto( udpfd, buf, UDP_BUFFER_SIZE-1, 0, ( struct sockaddr* )&client_address, client_addrlength );

                }

            }

            else if ( events[i].events & EPOLLIN )

            {

                char buf[ TCP_BUFFER_SIZE ];

                while( 1 )

                {

                    memset( buf, '\0', TCP_BUFFER_SIZE );

                    ret = recv( sockfd, buf, TCP_BUFFER_SIZE-1, 0 );

                    if( ret < 0 )

                    {

                        if( ( errno == EAGAIN ) || ( errno == EWOULDBLOCK ) )

                        {

                            break;

                        }

                        close( sockfd );

                        break;

                    }

                    else if( ret == 0 )

                    {

                        close( sockfd );

                    }

                    else

                    {

                        send( sockfd, buf, ret, 0 );

                    }

                }

            }

            else

            {

                printf( "something else happened \n" );

            }

        }

    }

    close( listenfd );

    return 0;

}