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TCP Full Duplex Server Client Communication (TheAlgorithms#856)
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* TCP Full Duplex Server Client Communication

* Changes made to successfully complete 5th Check

* Update client_server/tcp_full_duplex_server.c

Co-authored-by: David Leal <[email protected]>

* updating DIRECTORY.md

* Update tcp_full_duplex_client.c

* Update client_server/tcp_full_duplex_client.c

Co-authored-by: David Leal <[email protected]>

Co-authored-by: David Leal <[email protected]>
Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>
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@NVombat @Panquesito7
3 people authored Sep 22, 2021
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2 changes: 2 additions & 0 deletions DIRECTORY.md
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## Client Server
* [Client](https://github.com/TheAlgorithms/C/blob/master/client_server/client.c)
* [Server](https://github.com/TheAlgorithms/C/blob/master/client_server/server.c)
* [Tcp Full Duplex Client](https://github.com/TheAlgorithms/C/blob/master/client_server/tcp_full_duplex_client.c)
* [Tcp Full Duplex Server](https://github.com/TheAlgorithms/C/blob/master/client_server/tcp_full_duplex_server.c)
* [Tcp Half Duplex Client](https://github.com/TheAlgorithms/C/blob/master/client_server/tcp_half_duplex_client.c)
* [Tcp Half Duplex Server](https://github.com/TheAlgorithms/C/blob/master/client_server/tcp_half_duplex_server.c)
* [Udp Client](https://github.com/TheAlgorithms/C/blob/master/client_server/udp_client.c)
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173 changes: 173 additions & 0 deletions client_server/tcp_full_duplex_client.c
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/**
* @file
* @author [NVombat](https://github.com/NVombat)
* @brief Client-side implementation of [TCP Full Duplex
* Communication](http://www.tcpipguide.com/free/t_SimplexFullDuplexandHalfDuplexOperation.htm)
* @see tcp_full_duplex_server.c
*
* @details
* The algorithm is based on the simple TCP client and server model. However,
* instead of the server only sending and the client only receiving data,
* The server and client can both send and receive data simultaneously. This is
* implemented by using the `fork` function call so that in the server the child
* process can recieve data and parent process can send data, and in the client
* the child process can send data and the parent process can receive data. It
* runs an infinite loop and can send and receive messages indefinitely until
* the user exits the loop. In this way, the Full Duplex Form of communication
* can be represented using the TCP server-client model & socket programming
*/

#include <arpa/inet.h> /// For the type in_addr_t and in_port_t
#include <netdb.h> /// For structures returned by the network database library - formatted internet addresses and port numbers
#include <netinet/in.h> /// For in_addr and sockaddr_in structures
#include <stdint.h> /// For specific bit size values of variables
#include <stdio.h> /// Variable types, several macros, and various functions for performing input and output
#include <stdlib.h> /// Variable types, several macros, and various functions for performing general functions
#include <string.h> /// Various functions for manipulating arrays of characters
#include <sys/socket.h> /// For macro definitions related to the creation of sockets
#include <sys/types.h> /// For definitions to allow for the porting of BSD programs
#include <unistd.h> /// For miscellaneous symbolic constants and types, and miscellaneous functions

#define PORT 10000 /// Define port over which communication will take place

/**
* @brief Utility function used to print an error message to `stderr`.
* It prints `str` and an implementation-defined error
* message corresponding to the global variable `errno`.
* @returns void
*/
void error()
{
perror("Socket Creation Failed");
exit(EXIT_FAILURE);
}

/**
* @brief Main function
* @returns 0 on exit
*/
int main()
{
/** Variable Declarations */
uint32_t
sockfd; ///< socket descriptors - Like file handles but for sockets
char sendbuff[1024],
recvbuff[1024]; ///< character arrays to read and store string data
/// for communication

struct sockaddr_in
server_addr; ///< asic structures for all syscalls and functions that
/// deal with internet addresses. Structures for handling
/// internet addresses

/**
* The TCP socket is created using the socket function.
*
* AF_INET (Family) - it is an address family that is used to designate the
* type of addresses that your socket can communicate with
*
* SOCK_STREAM (Type) - Indicates TCP Connection - A stream socket provides
* for the bidirectional, reliable, sequenced, and unduplicated flow of data
* without record boundaries. Aside from the bidirectionality of data flow,
* a pair of connected stream sockets provides an interface nearly identical
* to pipes.
*
* 0 (Protocol) - Specifies a particular protocol to be used with the
* socket. Specifying a protocol of 0 causes socket() to use an unspecified
* default protocol appropriate for the requested socket type.
*/
if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
{
error();
}

/**
* Server Address Information
*
* The bzero() function erases the data in the n bytes of the memory
* starting at the location pointed to, by writing zeros (bytes
* containing '\0') to that area.
*
* We bind the server_addr to the internet address and port number thus
* giving our socket an identity with an address and port where it can
* listen for connections
*
* htons - The htons() function translates a short integer from host byte
* order to network byte order
*
* htonl - The htonl() function translates a long integer from host byte
* order to network byte order
*
* These functions are necessary so that the binding of address and port
* takes place with data in the correct format
*/
bzero(&server_addr, sizeof(server_addr));
server_addr.sin_family = AF_INET;
server_addr.sin_port = htons(PORT);
server_addr.sin_addr.s_addr = htonl(INADDR_ANY);

printf("Client is running...\n");

/**
* Connects the client to the server address using the socket descriptor
* This enables the two to communicate and exchange data
*/
connect(sockfd, (struct sockaddr *)&server_addr, sizeof(server_addr));

printf("Client is connected...\n");

/**
* Communication between client and server
*
* The bzero() function erases the data in the n bytes of the memory
* starting at the location pointed to, by writing zeros (bytes
* containing '\0') to that area. The variables are emptied and then
* ready for use
*
* The fork function call is used to create a child and parent process
* which run and execute code simultaneously
*
* The child process is used to send data and after doing so
* sleeps for 5 seconds to wait for the parent to receive data
*
* The parent process is used to receive data and after doing so
* sleeps for 5 seconds to wait for the child to send data
*
* The server and client can communicate indefinitely till one of them
* exits the connection
*
* Since the exchange of information between the server and client takes
* place simultaneously this represents FULL DUPLEX COMMUNICATION
*/
pid_t pid;
pid = fork();
if (pid == 0) /// Value of 0 is for child process
{
while (1)
{
bzero(&sendbuff, sizeof(sendbuff));
printf("\nType message here: ");
fgets(sendbuff, 1024, stdin);
send(sockfd, sendbuff, strlen(sendbuff) + 1, 0);
printf("\nMessage sent!\n");
sleep(5);
// break;
}
}
else /// Parent Process
{
while (1)
{
bzero(&recvbuff, sizeof(recvbuff));
recv(sockfd, recvbuff, sizeof(recvbuff), 0);
printf("\nSERVER: %s\n", recvbuff);
sleep(5);
// break;
}
}

/// Close Socket
close(sockfd);
printf("Client is offline...\n");
return 0;
}
195 changes: 195 additions & 0 deletions client_server/tcp_full_duplex_server.c
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/**
* @file
* @author [NVombat](https://github.com/NVombat)
* @brief Server-side implementation of [TCP Full Duplex
* Communication](http://www.tcpipguide.com/free/t_SimplexFullDuplexandHalfDuplexOperation.htm)
* @see tcp_full_duplex_server.c
*
* @details
* The algorithm is based on the simple TCP client and server model. However,
* instead of the server only sending and the client only receiving data,
* The server and client can both send and receive data simultaneously. This is
* implemented by using the `fork` function call so that in the server the child
* process can recieve data and parent process can send data, and in the client
* the child process can send data and the parent process can receive data. It
* runs an infinite loop and can send and receive messages indefinitely until
* the user exits the loop. In this way, the Full Duplex Form of communication
* can be represented using the TCP server-client model & socket programming
*/

#include <arpa/inet.h> /// For the type in_addr_t and in_port_t
#include <netdb.h> /// For structures returned by the network database library - formatted internet addresses and port numbers
#include <netinet/in.h> /// For in_addr and sockaddr_in structures
#include <stdint.h> /// For specific bit size values of variables
#include <stdio.h> /// Variable types, several macros, and various functions for performing input and output
#include <stdlib.h> /// Variable types, several macros, and various functions for performing general functions
#include <string.h> /// Various functions for manipulating arrays of characters
#include <sys/socket.h> /// For macro definitions related to the creation of sockets
#include <sys/types.h> /// For definitions to allow for the porting of BSD programs
#include <unistd.h> /// For miscellaneous symbolic constants and types, and miscellaneous functions

#define PORT 10000 /// Define port over which communication will take place

/**
* @brief Utility function used to print an error message to `stderr`.
* It prints `str` and an implementation-defined error
* message corresponding to the global variable `errno`.
* @returns void
*/
void error()
{
perror("Socket Creation Failed");
exit(EXIT_FAILURE);
}

/**
* @brief Main function
* @returns 0 on exit
*/
int main()
{
/** Variable Declarations */
uint32_t sockfd,
conn; ///< socket descriptors - Like file handles but for sockets
char recvbuff[1024],
sendbuff[1024]; ///< character arrays to read and store string data
/// for communication

struct sockaddr_in server_addr,
client_addr; ///< asic structures for all syscalls and functions that
/// deal with internet addresses. Structures for handling
/// internet addresses
socklen_t ClientLen; /// size of address

/**
* The TCP socket is created using the socket function
*
* AF_INET (Family) - it is an address family that is used to designate the
* type of addresses that your socket can communicate with
*
* SOCK_STREAM (Type) - Indicates TCP Connection - A stream socket provides
* for the bidirectional, reliable, sequenced, and unduplicated flow of data
* without record boundaries. Aside from the bidirectionality of data flow,
* a pair of connected stream sockets provides an interface nearly identical
* to pipes
*
* 0 (Protocol) - Specifies a particular protocol to be used with the
* socket. Specifying a protocol of 0 causes socket() to use an unspecified
* default protocol appropriate for the requested socket type
*/
if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
{
error(); ///< Error if the socket descriptor has a value lower than 0 -
/// socket wasnt created
}

/**
* Server Address Information
*
* The bzero() function erases the data in the n bytes of the memory
* starting at the location pointed to, by writing zeros (bytes
* containing '\0') to that area
*
* We bind the server_addr to the internet address and port number thus
* giving our socket an identity with an address and port where it can
* listen for connections
*
* htons - The htons() function translates a short integer from host byte
* order to network byte order
*
* htonl - The htonl() function translates a long integer from host byte
* order to network byte order
*
* These functions are necessary so that the binding of address and port
* takes place with data in the correct format
*/
bzero(&server_addr, sizeof(server_addr));
server_addr.sin_family = AF_INET;
server_addr.sin_port = htons(PORT);
server_addr.sin_addr.s_addr = htonl(INADDR_ANY);

printf("Server is running...\n");

/**
* This binds the socket descriptor to the server thus enabling the server
* to listen for connections and communicate with other clients
*/
if (bind(sockfd, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0)
{
error(); /// If binding is unsuccessful
}
/**
* This is to listen for clients or connections made to the server
*
* The limit is currently at 5 but can be increased to listen for
* more connections
*
* It listens to connections through the socket descriptor
*/
listen(sockfd, 5);

printf("Server is listening...\n");

/**
* When a connection is found, a socket is created and connection is
* accepted and established through the socket descriptor
*/
conn = accept(sockfd, (struct sockaddr *)NULL, NULL);

printf("Server is connected...\n");

/**
* Communication between client and server
*
* The bzero() function erases the data in the n bytes of the memory
* starting at the location pointed to, by writing zeros (bytes
* containing '\0') to that area. The variables are emptied and then
* ready for use
*
* The fork function call is used to create a child and parent process
* which run and execute code simultaneously
*
* The child process is used to receive data and after doing so
* sleeps for 5 seconds to wait for the parent to send data
*
* The parent process is used to send data and after doing so
* sleeps for 5 seconds to wait for the child to receive data
*
* The server and client can communicate indefinitely till one of them
* exits the connection
*
* Since the exchange of information between the server and client takes
* place simultaneously this represents FULL DUPLEX COMMUNICATION
*/
pid_t pid;
pid = fork();
if (pid == 0) /// Value of 0 is for child process
{
while (1)
{
bzero(&recvbuff, sizeof(recvbuff));
recv(conn, recvbuff, sizeof(recvbuff), 0);
printf("\nCLIENT : %s\n", recvbuff);
sleep(5);
// break;
}
}
else /// Parent process
{
while (1)
{
bzero(&sendbuff, sizeof(sendbuff));
printf("\nType message here: ");
fgets(sendbuff, 1024, stdin);
send(conn, sendbuff, strlen(sendbuff) + 1, 0);
printf("\nMessage Sent!\n");
sleep(5);
// break;
}
}

/// Close socket
close(sockfd);
printf("Server is offline...\n");
return 0;
}

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