Linux network multi-thread programming example

UDP is used.
The server can accept ten clients at the same time, and each client can communicate with each other point-to-point.
The client broadcast of the server. It can also communicate with the server. The server can also broadcast.
You must first understandSource codeCommand in: "/W" broadcast; "/s n" to a client; "/SV" to the server;

The command is the part in quotation marks. Pay attention to spaces.

ServerCode:

# Include <sys/STAT. h>
# Include <fcntl. h>
# Include <unistd. h>
# Include <sys/types. h>
# Include <sys/socket. h>
# Include <sys/Wait. H>
# Include <netinet/in. h>
# Include <ARPA/inet. h>
# Include <stdio. h>
# Include <string. h>
# Include <stdlib. h>
# Include <pthread. h>
# Define Port 8889
# Deprecision max_size 256
//////////////////////////////////////// /////////////////
Int sockfd, sockfd2 [10], RET, I = 0, J, flag = 0;
Struct sockaddr_in ADDR;
Struct sockaddr_in addr2 [10];
Int unsigned addr_len = sizeof (struct sockaddr_in );
Char inbuffer [256];
Char outbuffer [256];
// Char tempbuffer [256];
// Int name [1];
Void threads1 ();
Void threads2 ();
//////////////////////////////////////// ///////////////
Int main ()
{
If (sockfd = socket (af_inet, sock_dgram, 0) <0)
{Perror ("socket ");
Exit (1 );
}
Bzero (& ADDR, sizeof (ADDR ));
ADDR. sin_family = af_inet;
ADDR. sin_port = htons (port );
ADDR. sin_addr.s_addr = htonl (inaddr_any );
If (BIND (sockfd, (struct sockaddr *) & ADDR, sizeof (ADDR) <0)
{
Perror ("Connect ");
Exit (1 );
}
Pthread_t ids1;
Ret = pthread_create (& ids1, null, (void *) & threads1, null );
If (Ret! = 0)
{
Printf ("cross-region slow drag \ n ");
Exit (1 );
}

Pthread_t ids2;
Ret = pthread_create (& ids2, null, (void *) & threads2, null );
If (Ret! = 0)
{
Printf ("cross-region slow drag \ n ");
Exit (1 );
}
Pthread_join (ids1, null );
Pthread_join (ids2, null );

Close (sockfd );
Return 1;
}
//////////////////////////////////////// ////////////////////
Void threads1 (void)
{
For (;
{
Bzero (outbuffer, sizeof (outbuffer ));
Read (stdin_fileno, outbuffer, sizeof (outbuffer ));
If (strncmp (outbuffer, "/W", 3) = 0) //
{
Strcat (outbuffer, "server said :");
If (addr2 [0]. sin_port! = 0)
{
For (j = 0; j <= 9; j ++)
{
If (addr2 [J]. sin_port! = 0) // forward to another client
{
Sendto (sockfd2 [J], outbuffer, strlen (outbuffer), 0, (struct sockaddr *) & addr2 [J], addr_len );
Perror ("sendto ");
}
}
} Else {
Printf ("No clent \ n ");
}
}
Else if (strncmp (outbuffer, "/s", 3) = 0) //// // to a client
{
If (strncmp (outbuffer, "/S 0", 5) = 0)
{

Sendto (sockfd2 [0], outbuffer, strlen (outbuffer), 0, (struct sockaddr *) & addr2 [0], addr_len );
Perror ("sendto ");
}
Else if (strncmp (outbuffer, "/S 1", 5) = 0)
{

Sendto (sockfd2 [1], outbuffer, strlen (outbuffer), 0, (struct sockaddr *) & addr2 [1], addr_len );
Perror ("sendto ");
}
Else if (strncmp (outbuffer, "/S 2", 5) = 0)
{

Sendto (sockfd2 [2], outbuffer, strlen (outbuffer), 0, (struct sockaddr *) & addr2 [2], addr_len );
Perror ("sendto ");
}
Else if (strncmp (outbuffer, "/S 3", 5) = 0)
{

Sendto (sockfd2 [3], outbuffer, strlen (outbuffer), 0, (struct sockaddr *) & addr2 [3], addr_len );
Perror ("sendto ");
}
Else if (strncmp (outbuffer, "/S 4", 5) = 0)
{

Sendto (sockfd2 [4], outbuffer, strlen (outbuffer), 0, (struct sockaddr *) & addr2 [4], addr_len );
Perror ("sendto ");
}
Else if (strncmp (outbuffer, "/S 5", 5) = 0)
{

Sendto (sockfd2 [5], outbuffer, strlen (outbuffer), 0, (struct sockaddr *) & addr2 [5], addr_len );
Perror ("sendto ");
}
Else if (strncmp (outbuffer, "/S 6", 5) = 0)
{

Sendto (sockfd2 [6], outbuffer, strlen (outbuffer), 0, (struct sockaddr *) & addr2 [6], addr_len );
Perror ("sendto ");
}
Else if (strncmp (outbuffer, "/S 7", 5) = 0)
{

Sendto (sockfd2 [7], outbuffer, strlen (outbuffer), 0, (struct sockaddr *) & addr2 [7], addr_len );
Perror ("sendto ");
}
Else if (strncmp (outbuffer, "/S 8", 5) = 0)
{

Sendto (sockfd2 [8], outbuffer, strlen (outbuffer), 0, (struct sockaddr *) & addr2 [8], addr_len );
Perror ("sendto ");
}
Else if (strncmp (outbuffer, "/S 9", 5) = 0)
{

Sendto (sockfd2 [9], outbuffer, strlen (outbuffer), 0, (struct sockaddr *) & addr2 [9], addr_len );
Perror ("sendto ");
}
}
Else {
Printf ("error message! \ N ");
}
}
}
//////////////////////////////////////// ////////////////////
Void threads2 (void)
{
For (j = 0; j <= 9; j ++)
{
Addr2 [J]. sin_family = af_inet;
Addr2 [J]. sin_addr.s_addr = 0;
Addr2 [J]. sin_port = 0;
}
For (;{
Bzero (inbuffer, sizeof (inbuffer ));
Recvfrom (sockfd, inbuffer, sizeof (inbuffer), 0, (struct sockaddr *) & ADDR, & addr_len );

Printf ("receive from clent --> % s", inbuffer );
For (j = 0; j <= 9; j ++)
{
If (ADDR. sin_port = addr2 [J]. sin_port) Flag = Flag + 1; // determine whether the client is logged on

}
If (flag = 0) // if not, record
{
Sockfd2 [I] = sockfd;
Addr2 [I]. sin_port = ADDR. sin_port;
Addr2 [I]. sin_addr.s_addr = ADDR. sin_addr.s_addr;
If (I = 9) I = 0;
I = I + 1;
}
Flag = 0;
/// // Before sending
If (strncmp (inbuffer, "/W", 3) = 0) //
{
Strcat (inbuffer, "A clent said to everone ");
If (addr2 [0]. sin_port! = 0)
{
For (j = 0; j <= 9; j ++)
{
If (addr2 [J]. sin_port! = 0 & addr2 [J]. sin_port! = ADDR. sin_port) // forward to another client
{
Sendto (sockfd2 [J], inbuffer, strlen (inbuffer), 0, (struct sockaddr *) & addr2 [J], addr_len );
Perror ("sendto ");
}
}
}
}
Else if (strncmp (inbuffer, "/s", 3) = 0) //// // to a client
{
If (strncmp (inbuffer, "/S 0", 5) = 0)
{

Sendto (sockfd2 [0], inbuffer, strlen (inbuffer), 0, (struct sockaddr *) & addr2 [0], addr_len );
Perror ("sendto ");
}
Else if (strncmp (inbuffer, "/S 1", 5) = 0)
{

Sendto (sockfd2 [1], inbuffer, strlen (inbuffer), 0, (struct sockaddr *) & addr2 [1], addr_len );
Perror ("sendto ");
}
Else if (strncmp (inbuffer, "/S 2", 5) = 0)
{

Sendto (sockfd2 [2], inbuffer, strlen (inbuffer), 0, (struct sockaddr *) & addr2 [2], addr_len );
Perror ("sendto ");
}
Else if (strncmp (inbuffer, "/S 3", 5) = 0)
{

Sendto (sockfd2 [3], inbuffer, strlen (inbuffer), 0, (struct sockaddr *) & addr2 [3], addr_len );
Perror ("sendto ");
}
Else if (strncmp (inbuffer, "/S 4", 5) = 0)
{

Sendto (sockfd2 [4], inbuffer, strlen (inbuffer), 0, (struct sockaddr *) & addr2 [4], addr_len );
Perror ("sendto ");
}
Else if (strncmp (inbuffer, "/S 5", 5) = 0)
{

Sendto (sockfd2 [5], inbuffer, strlen (inbuffer), 0, (struct sockaddr *) & addr2 [5], addr_len );
Perror ("sendto ");
}
Else if (strncmp (inbuffer, "/S 6", 5) = 0)
{

Sendto (sockfd2 [6], inbuffer, strlen (inbuffer), 0, (struct sockaddr *) & addr2 [6], addr_len );
Perror ("sendto ");
}
Else if (strncmp (inbuffer, "/S 7", 5) = 0)
{

Sendto (sockfd2 [7], inbuffer, strlen (inbuffer), 0, (struct sockaddr *) & addr2 [7], addr_len );
Perror ("sendto ");
}
Else if (strncmp (inbuffer, "/S 8", 5) = 0)
{

Sendto (sockfd2 [8], inbuffer, strlen (inbuffer), 0, (struct sockaddr *) & addr2 [8], addr_len );
Perror ("sendto ");
}
Else if (strncmp (inbuffer, "/S 9", 5) = 0)
{
Sendto (sockfd2 [9], inbuffer, strlen (inbuffer), 0, (struct sockaddr *) & addr2 [9], addr_len );
Perror ("sendto ");
}
}
Else if (strncmp (inbuffer, "/SV", 4) = 0) //
{
Printf ("clent to server \ n ");
}
Else {
Bzero (inbuffer, sizeof (inbuffer ));
Strcpy (inbuffer, "The message error! ");
Sendto (sockfd, inbuffer, strlen (inbuffer), 0, (struct sockaddr *) & ADDR, addr_len); // notify the client if the message format is incorrect
Perror ("sendto ");
}
}
}

Bytes ----------------------------------------------------------------------------------------------------------------
Client code:

# Include <sys/STAT. h>
# Include <fcntl. h>
# Include <unistd. h>
# Include <sys/types. h>
# Include <sys/Wait. H>
# Include <sys/socket. h>
# Include <netinet/in. h>
# Include <ARPA/inet. h>
# Include <stdio. h>
# Include <string. h>
# Include <stdlib. h>
# Define Port 8889
# Deprecision max_size 256
# Define server_ip "127.0.0.1"
//////////////////////////////////////// /////////
Int sockfd;
Struct sockaddr_in ADDR;
Int unsigned addr_len = sizeof (struct sockaddr_in );
Char inbuffer [256];
Char outbuffer [256];

//////////////////////////////////////// ///////////
Void threads1 ();
Void threads2 ();

Int main (void)
{
If (sockfd = socket (af_inet, sock_dgram, 0) <0)
{
Perror ("socket ");
Exit (1 );
}
Bzero (& ADDR, sizeof (ADDR ));
ADDR. sin_family = af_inet;
ADDR. sin_port = htons (port );
ADDR. sin_addr.s_addr = inet_addr (server_ip );

Pthread_t ids1;
Pthread_t ids2;
If (pthread_create (& ids1, null, (void *) & threads1, null )! = 0)
{
Printf ("thread creation error \ n ");
Exit (1 );
}

// Pthread_mutex_init (& mutex, null );
If (pthread_create (& ids2, null, (void *) & threads2, null )! = 0)
{
Printf ("thread creation error \ n ");
Exit (1 );
}
Pthread_join (ids1, null );
Pthread_join (ids2, null );
Close (sockfd );
Return 1;
}

//////////////////////////////////////// ///////////////////

Void threads1 ()
{

For (;;){
Bzero (outbuffer, sizeof (outbuffer ));
Fgets (outbuffer, max_size, stdin );
Sendto (sockfd, outbuffer, strlen (outbuffer), 0, (struct sockaddr *) & ADDR, addr_len );
}
}

Void threads2 ()
{
For (;;){
Bzero (inbuffer, sizeof (inbuffer ));
Recvfrom (sockfd, inbuffer, sizeof (inbuffer), 0, (struct sockaddr *) & ADDR, & addr_len );
Printf ("receive from server -->: % s \ n", inbuffer );
}
}

Be careful that the symbols in the source code may be used as escape characters.
If a compilation error occurs, add your own symbols.