qotd/server.c

//
// Created by k0rb4k on 30/03/2021.
//

#include "server.h"
#include "config.h"

// TODO: object-like C

extern int errno;

_Noreturn void udpListen(int serverSocket, struct sockaddr *clientAddress, unsigned long addressLength)
{
    char clientMessage[MESSAGE_STRING_LENGTH], quote[MESSAGE_STRING_LENGTH];

    for (;;)
    {
        // receive data

        if (recvfrom(serverSocket, clientMessage, MESSAGE_STRING_LENGTH, 0, clientAddress, (socklen_t *)&addressLength) >= 0)
        {
            printf("received: %s\n", clientMessage);

            // send data
            getRandomQuote(quote);
            printf("sending: %s\n", quote);
            if (sendto(serverSocket, quote, strlen(quote), 0, clientAddress, addressLength) == -1)
            {
                perror("udp: sendto");
            }
        }
        else
        {
            perror("udp: recvfrom");
        }
    }
}

void tcpListen(int serverSocket, struct sockaddr *clientAddress, unsigned long addressLength)
{
    int clientSocket;
    char quote[MESSAGE_STRING_LENGTH] = "", clientMessage[MESSAGE_STRING_LENGTH] = "";

    listen(serverSocket, 5);
    puts("server listening");

    // accept connections
    // TODO: t h r e a d s
    while ((clientSocket = accept(serverSocket, clientAddress, (socklen_t *)&addressLength)) >= 0)
    {
        puts("client connected");

        getRandomQuote(quote);
        printf("responding: \"%s\"\n", quote);
        if (send(clientSocket, quote, strlen(quote), 0) == -1)
        {
            perror("tcp: send");
        }
        close(clientSocket);

        puts("closed connection");
    }

    if (clientSocket < 0)
    {
        puts("client connection failed");
        exit(3);
    }
}

void server(int tcp, int ipv6)
{
    int serverSocket, socketType, socketProtocol;
    unsigned long serverAddressLength, clientAddressLength;
    struct sockaddr *serverAddress, *clientAddress;
    struct sockaddr_in serverAddress4, clientAddress4;
    struct sockaddr_in6 serverAddress6, clientAddress6;

    if (ipv6)
    {
        serverAddress6.sin6_family = AF_INET6;
        serverAddress6.sin6_addr = in6addr_any;
        serverAddress6.sin6_port = htons(DEFAULT_LISTEN_PORT);
        serverAddress = (struct sockaddr *)&serverAddress6;
        serverAddressLength = sizeof serverAddress6;

        clientAddress6.sin6_family = AF_INET6;
        clientAddress = (struct sockaddr *)&clientAddress6;
        clientAddressLength = sizeof clientAddress6;
    }
    else
    {
        serverAddress4.sin_family = AF_INET;
        serverAddress4.sin_addr.s_addr = INADDR_ANY;
        serverAddress4.sin_port = htons(DEFAULT_LISTEN_PORT);
        serverAddress = (struct sockaddr *)&serverAddress4;
        serverAddressLength = sizeof serverAddress4;

        clientAddress4.sin_family = AF_INET;
        clientAddress = (struct sockaddr *)&clientAddress4;
        clientAddressLength = sizeof clientAddress4;
    }

    if (tcp)
    {
        socketType = SOCK_STREAM;
        socketProtocol = IPPROTO_TCP;
    }
    else
    {
        socketType = SOCK_DGRAM;
        socketProtocol = IPPROTO_UDP;
    }

    // create sock
    serverSocket = socket(serverAddress->sa_family, socketType, socketProtocol);
    if (serverSocket == -1)
    {
        puts("socket not created");
        exit(1);
    }
    puts("socket created");

    // bind sock
    if (bind(serverSocket, serverAddress, serverAddressLength) < 0)
    {
        puts("bind failed");
        exit(2);
    }

    // TODO: threads to run both at the same time
    if (tcp)
    {
        tcpListen(serverSocket, clientAddress, clientAddressLength);
    }
    else
    {
        udpListen(serverSocket, clientAddress, clientAddressLength);
    }
}