pull in very simple client/server demo code

inspired by http://www.linuxhowtos.org/C_C++/socket.htm

source/client/client.cpp

@@ -1,7 +1,85 @@
 #include "client.h"
 
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+
+#include <netdb.h>
+
+#include "net.h"
 
 int runClient(int argc, char* argv[])
 {
+    int sockfd; 	// socket File descriptor
+    int portno;		// Port number
+    int n = 0;		// return value for read and write calls
+
+    struct sockaddr_in serv_addr; // Server address
+
+    struct hostent *server; // pointer to host information
+
+    char buffer[1028]; // buffer for socked read
+    memset(buffer,0,sizeof(buffer));
+
+    // must provide information
+    if (argc < 2)
+    {
+        fprintf(stderr,"usage %s hostname\n", argv[0]);
+        exit(0);
+    }
+
+    // Get port number
+    portno = 11715;
+
+    // Create a new socket
+    // AF_INET is general internetsocked domain
+    // SOCK_STREAM as messages will be read in on this socket, SOCK_DGRAM would be for packets
+    // 0 is for default protocol
+    sockfd = socket(AF_INET, SOCK_STREAM, 0);
+    if (sockfd < 0)
+        error("ERROR opening socket");
+
+    // Get the hostent information for the host by name
+    server = gethostbyname(argv[1]);
+    if (server == NULL)
+        error("ERROR, no such host");
+
+    // Empty the server address struct
+    memset(&serv_addr,0, sizeof(serv_addr));
+
+    // Set the server to AF_INET
+    serv_addr.sin_family = AF_INET;
+
+    // copy the server address into our server_addr struct
+    memcpy(&serv_addr.sin_addr.s_addr, server->h_addr, server->h_length);
+
+    // Set our server address port to the port number provided
+    serv_addr.sin_port = htons(portno);
+
+    // Attempt to connect to the server using the socket and server address info
+    if (connect(sockfd, (const sockaddr*)&serv_addr, sizeof(serv_addr)) < 0)
+        error("ERROR connecting");
+
+    while ( n >= 0 )
+    {
+        // Get the message to send
+        printf("Please enter the message: ");
+        memset(buffer,0,sizeof(buffer));
+        fgets(buffer,sizeof(buffer)-1,stdin);
+
+        // Place a test message into the buffer
+        strncpy(buffer,buffer,sizeof(buffer));
+
+        // Write to the socket with the buffer
+        n = write(sockfd,buffer,strlen(buffer));
+        if (n < 0)
+            error("ERROR writing to socket");
+    }
+
     return 0;
 }

source/client/client.h

@@ -1,8 +1,6 @@
 #ifndef _TTRTS_CLIENT_H_
 #define _TTRTS_CLIENT_H_
 
-#include <string>
-
 int runClient(int argc, char* argv[]);
 
 #endif

source/client/main.cpp

@@ -24,9 +24,9 @@ int main(int argc, char* argv[])
 
 	// Either run the client, the server, or from local filesystem
 	if( arg1 == "client" )
-		return runClient(argc,argv+1);
+		return runClient(argc-1,argv+1);
 	else if ( arg1 == "server" )
-		return runServer(argc,argv+1);
+		return runServer(argc-1,argv+1);
 	else
 		return runFromFilesystem(argc,argv);
 

source/client/net.h

@@ -1,4 +1,13 @@
 #ifndef _TTRTS_NET_H_
 #define _TTRTS_NET_H_
 
+#include <stdio.h>
+#include <stdlib.h>
+
+inline void error(const char *msg)
+{
+    perror(msg);
+    exit(1);
+}
+
 #endif

source/client/server.cpp

@@ -1,6 +1,93 @@
 #include "server.h"
 
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <sys/types.h>
+#include <sys/socket.h>
+
+#include <netinet/in.h>
+
+#include "net.h"
+
 int runServer(int argc, char* argv[])
 {
+    int sockfd; 	// socket File descriptor
+    int newsockfd; 	// new socket File descriptor
+
+    int portno;		// Port number
+    socklen_t clilen;		// length of client address
+    clilen = sizeof(sockaddr_in);
+
+    int n = 0;			// return value for read and write calls
+
+    char buffer[1028]; // buffer for socked read
+    memset(buffer,0,sizeof(buffer));
+
+    struct sockaddr_in serv_addr; // Server address
+    struct sockaddr_in cli_addr;  // Client address
+
+    // Create a new socket
+    // AF_INET is general internetsocked domain
+    // SOCK_STREAM as messages will be read in on this socket, SOCK_DGRAM would be for packets
+    // 0 is for default protocol
+    sockfd = socket(AF_INET, SOCK_STREAM, 0);
+    if (sockfd < 0)
+        error("ERROR opening socket");
+
+    // empty the server address
+    memset(&serv_addr,0, sizeof(serv_addr));
+
+    // Grab the port number
+    portno = 11715;
+
+    // Set the server address family to AF_INET
+    serv_addr.sin_family = AF_INET;
+
+    // Set the port number
+    // htons swaps from host byte order to network byte order
+    serv_addr.sin_port = htons(portno);
+
+    // The host for this address is this current machines's IP
+    // INADDR_ANY fetches this
+    serv_addr.sin_addr.s_addr = INADDR_ANY;
+
+    // bind out socket to this server address
+    if (bind(sockfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0)
+        error("ERROR on binding");
+
+    // Listen on the socket for messages
+    // Second param is length of backlog queue, the maximum number of connections
+    // that can be waiting while the process is handling a single connection
+    // max is usually set to 5
+    listen(sockfd,5);
+
+    // accept waits for a connection from a client
+    // it returns a new socket file descriptor for this connection
+    // client information will be stored in cli_addr
+    newsockfd = accept(sockfd, (struct sockaddr *) &cli_addr, &clilen);
+    if (newsockfd < 0)
+        error("ERROR on accept");
+
+    // loop
+    while( n >= 0 )
+    {
+        // empty the buffer
+        memset(buffer,0,sizeof(buffer));
+
+        // Read in the new socket
+        // read will block until the client has called write
+        // up to the full size of the buffer
+        n = read(newsockfd,buffer,sizeof(buffer)-1);
+        if (n < 0)
+            error("ERROR reading from socket");
+
+        // print the message recieved
+        printf("%s",buffer);
+    }
+
+    // Return
     return 0;
 }