Linux Network Programming--time-out detection

Network timeout Detection (1)

Set the properties of the socket So_rcvtimeo

Reference code:

struct Timeval TV;

TV.. tv_sec=5;//Set 5s time

tv.tv_usec=0;

SetSockOpt (SOCKFD,SOL_SOCKET,SO_RCVTIMEO,&TV,SIZEOF (TV));//Set Receive timeout

Recv/recvfrom

Network Timeout Check (2)

Use Select to detect if the socket is ' ready '

Reference code:

struct Fd_set Rdfds;

struct Timeval tv={5,0};

Fd_zero (&rdfds);

Fd_set (Sockfd,&rdfds);

if (Selecet (SOCKFD+1,&RDFS,NULL,NULL,&TV) >0)//socket ready

{

Recv/recvfrom

}

Selct-timeout.c

#include <stdio.h>#include<stdlib.h>#include<sys/types.h>#include<sys/socket.h>#include<unistd.h>#include<string.h>#include<netinet/inch.h>#include<arpa/inet.h>#include<sys/time.h>#defineN 128#defineErr_log (ErrLog) do{perror (ErrLog); exit (1);} while (0)intMainintargcConst Char*argv[])    {Fd_set Readfds; intmaxfd; inti =0; CharBuf[n] = {}; intret; intSOCKFD; intacceptfd; structsockaddr_in serveraddr, clientaddr; socklen_t Addrlen=sizeof(CLIENTADDR); if(ARGC <3) {fprintf (stderr,"usage:%s ServerIP port.\n", argv[0]); }    if(SOCKFD = socket (af_inet, Sock_stream,0)) <0) {Err_log ("fail to socket"); } serveraddr.sin_family=af_inet; Serveraddr.sin_addr.s_addr= Inet_addr (argv[1]); Serveraddr.sin_port= Htons (Atoi (argv[2])); if(Bind (SOCKFD, (structSOCKADDR *) &serveraddr,sizeof(SERVERADDR)) <0) {Err_log ("fail to bind"); }    if(Listen (SOCKFD,5) <0) {Err_log ("fail to listen"); } Fd_zero (&Readfds); Maxfd=SOCKFD; structTimeval TV;  while(1) {Fd_set (0, &Readfds); Fd_set (SOCKFD,&Readfds); Tv.tv_sec=5; Tv.tv_usec=0; if(ret =Select(maxfd+1, &readfds, NULL, NULL,&AMP;TV)) <0) {Err_log ("fail to select"); } printf ("After select.\n"); Switch(ret) { Case 0: printf ("timeout....\n");  Break; default :             for(i =0; I < maxfd+1; i++)            {                if(Fd_isset (I, &Readfds)) {                    if(i = =0) {fgets (buf, N, stdin); printf ("buf:%s", BUF); }                    if(i = =sockfd) {                        if(Acceptfd = Accept (SOCKFD, (structsockaddr*) (&AMP;CLIENTADDR, &addrlen)) <0) {Err_log ("fail to accept"); } printf ("%s----- ACCEPTFD =%d\n", Inet_ntoa (CLIENTADDR.SIN_ADDR), Ntohs (Clientaddr.sin_port), ACCEPTFD); }                }            } //End Default}//Endswitch    }        return 0;}

Network Timeout (3)

Set the timer (timer) to capture the SIGALRM signal

Reference code:

void handler (int signo) {return;}

Once the process receives this signal, after executing the signal processing function, the next function will return directly, without blocking where

struct Sigaction Act;

Sigaction (sigalrm,null,&act);

Act.sa_handler=handler

act.sa_flag&=~sa_restart;

Sigaction (Sigalrm,&act,null);

Alarm (5)

if (recv (...) <0) ....

Server-alarm.c

#include <stdio.h>#include<string.h>#include<stdlib.h>#include<sys/socket.h>#include<sys/types.h>#include<netinet/inch.h>#include<arpa/inet.h>#include<signal.h>#include<errno.h>#defineErr_log (ErrLog) do{perror (ErrLog); exit (1);} while (0)#defineN 128//./server 192.168.0.196 10000voidHandlerintSIG) {printf ("timeout....\n");}intMainintargcConst Char*argv[]) {    intSOCKFD; intCONFD; structsockaddr_in serveraddr, clientaddr; CharBuf[n] = {}; if(ARGC! =3) {fprintf (stderr,"usage:%s ServerIP port.\n", argv[0]); return-1; }    if(SOCKFD = socket (af_inet, Sock_stream,0)) <0) {Err_log ("fail to socket"); } printf ("SOCKFD =%d\n", SOCKFD); Serveraddr.sin_family=af_inet; Serveraddr.sin_addr.s_addr= Inet_addr (argv[1]); Serveraddr.sin_port= Htons (Atoi (argv[2])); if(Bind (SOCKFD, (structsockaddr*) &serveraddr,sizeof(SERVERADDR)) <0) {Err_log ("fail to bind"); }    if(Listen (SOCKFD,Ten) <0) {Err_log ("fail to listen"); } socklen_t Addrlen=sizeof(structsockaddr); if(CONFD = Accept (SOCKFD, (structSOCKADDR *) &clientaddr, &addrlen) <0) {Err_log ("fail to accept"); } printf ("CONFD =%d,%s-and%d \ n", CONFD, Inet_ntoa (CLIENTADDR.SIN_ADDR), Ntohs (Clientaddr.sin_port)); structSigaction Act; Sigaction (SIGALRM, NULL,&Act); Act.sa_handler=handler; Act.sa_flags&= ~Sa_restart; Sigaction (SIGALRM,&Act, NULL);  while(1) {Alarm (5); if(Recv (CONFD, buf, N,0) <0)        {            if(errno = =4) {printf ("errno =%d\n", errno); }            Else{Err_log ("fail to recv"); }} printf ("From client:%s\n", BUF);    } close (SOCKFD); return 0;}

Compile run, if the client does not enter for 5 seconds, you can see

Linux Network Programming--time-out detection