Linux socket TCP UDP bind synonymous IP and port

TCP and UDP can bind to the same IP & port. #include <sys/types.h> #include <sys/socket.h> #include <net inet/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 1024int 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;    Concern about Read Event 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));    ASSERT (Ret! =-1);    RET = Listen (LISTENFD, 5);    ASSERT (Ret! =-1);    Bzero (&address, sizeof (address));    address.sin_family = af_inet;    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));    ASSERT (Ret! =-1);    Epoll_event events[Max_event_number]; int EPOLLFD = Epoll_create ( 5);    ASSERT (EPOLLFD! =-1);    ADDFD (EPOLLFD, LISTENFD);    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);    if (CONNFD < 0) {printf ("errno is:%d\n", errno);                } else {ADDFD (EPOLLFD, CONNFD);        Char Remote[inet_addrstrlen]; printf ("Connected client IP:%s and port:%d\n", Inet_ntop (Af_inet, &client_address.sin_addr, remote, in Et_addrstrlen), NtohS (client_address.sin_port)); }}//udp is readable else if (sockfd = = udpfd) {char buf[U                Dp_buffer_size];                memset (buf, ' 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 sockadd                r*) &client_address, client_addrlength);                } else if (ret = = 0) {printf ("client peer closed () \ n");   Shutdown (UDPFD);                UDP sockets shutdown meaningless close (UDPFD);                } else {printf ("UDP Recvfrom ran into error: \ n", errno); HandlE error ....} }//tcp CONNFD is readable else if (events[i].events & Epollin) {ch                Ar buf[tcp_buffer_size];                    while (1) {memset (buf, ' n ', tcp_buffer_size);                    SOCKFD is nonblock ret = recv (SOCKFD, buf, tcp_buffer_size-1, 0); if (Ret < 0) {if (errno = = Eagain) | | (errno = = Ewouldblock) | |                        (errno = = eintr))                        {break; } else {printf ("TCP recv ran into error, close () Soc                        Ket.\n ");                        Close (SOCKFD);                        Break                    }} else if (ret = = 0)//peer called close () and sent a FIN to here               {     printf ("TCP recv return 0:peer client close (), so Close () self.\n");                    Close (SOCKFD); } else//normal, send back, and we have received!                    echo~ {Send (SOCKFD, buf, ret, 0);            }}} else {printf ("something else happened \ n");    }}} close (LISTENFD); return 0;}

　　

Linux socket TCP UDP bind synonymous IP and port