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54 lines
2.5 KiB
C
54 lines
2.5 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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void error(const char *msg) { perror(msg); exit(1); } // Error function used for reporting issues
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int main(int argc, char *argv[])
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{
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int listenSocketFD, establishedConnectionFD, portNumber, charsRead;
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socklen_t sizeOfClientInfo;
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char buffer[256];
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struct sockaddr_in serverAddress, clientAddress;
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if (argc < 2) { fprintf(stderr,"USAGE: %s port\n", argv[0]); exit(1); } // Check usage & args
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// Set up the address struct for this process (the server)
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memset((char *)&serverAddress, '\0', sizeof(serverAddress)); // Clear out the address struct
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portNumber = atoi(argv[1]); // Get the port number, convert to an integer from a string
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serverAddress.sin_family = AF_INET; // Create a network-capable socket
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serverAddress.sin_port = htons(portNumber); // Store the port number
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serverAddress.sin_addr.s_addr = INADDR_ANY; // Any address is allowed for connection to this process
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// Set up the socket
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listenSocketFD = socket(AF_INET, SOCK_STREAM, 0); // Create the socket
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if (listenSocketFD < 0) error("ERROR opening socket");
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// Enable the socket to begin listening
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if (bind(listenSocketFD, (struct sockaddr *)&serverAddress, sizeof(serverAddress)) < 0) // Connect socket to port
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error("ERROR on binding");
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listen(listenSocketFD, 5); // Flip the socket on - it can now receive up to 5 connections
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// Accept a connection, blocking if one is not available until one connects
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sizeOfClientInfo = sizeof(clientAddress); // Get the size of the address for the client that will connect
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establishedConnectionFD = accept(listenSocketFD, (struct sockaddr *)&clientAddress, &sizeOfClientInfo); // Accept
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if (establishedConnectionFD < 0) error("ERROR on accept");
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// Get the message from the client and display it
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memset(buffer, '\0', 256);
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charsRead = recv(establishedConnectionFD, buffer, 255, 0); // Read the client's message from the socket
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if (charsRead < 0) error("ERROR reading from socket");
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printf("SERVER: I received this from the client: \"%s\"\n", buffer);
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// Send a Success message back to the client
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charsRead = send(establishedConnectionFD, "I am the server, and I got your message", 39, 0); // Send success back
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if (charsRead < 0) error("ERROR writing to socket");
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close(establishedConnectionFD); // Close the existing socket which is connected to the client
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close(listenSocketFD); // Close the listening socket
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return 0;
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}
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