source: Daodan/Flatline/src/Flatline.c@ 458

#include "Flatline.h"

bool Net_Listen(uint16_t port, bool (*packet_callback)(char* data, int datalen, int from))
{
        int sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
        
        if (sock < 0)
        {
                DDrStartupMessage("could not create socket");
                return false;
        }
        
        sockaddr_in address;
        memset(&address, 0, sizeof(sockaddr_in));
        address.sin_family = AF_INET;
        address.sin_addr.s_addr = htonl(INADDR_ANY);
        address.sin_port = htons(port);
        
        if (bind(sock, (sockaddr*)&address, sizeof(sockaddr_in)) < 0)
        {
                DDrStartupMessage("could not bind port %d", port);
                closesocket(sock);
                return false;
        }
        
        char data[65537];
        data[sizeof(data) - 1] = '\0';
        sockaddr_in from;
        int recvlen;
        for (;;)
        {
                int fromlen = sizeof(sockaddr_in);
                memset(&from, 0, sizeof(sockaddr_in));
                recvlen = recvfrom(sock, data, sizeof(data) - 1, 0, (sockaddr*)&from, (void*)&fromlen);
                if (!packet_callback(data, recvlen, ntohl(from.sin_addr.s_addr)))
                        break;
        }
        closesocket(sock);
        return true;
}

int Net_CreateSocket(uint16_t port)
{
        int sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
        
        if (sock < 0)
        {
                DDrStartupMessage("could not create socket");
                return -1;
        }
        
        sockaddr_in address;
        memset(&address, 0, sizeof(sockaddr_in));
        address.sin_family = AF_INET;
        address.sin_addr.s_addr = htonl(INADDR_ANY);
        address.sin_port = htons(port);
        
        if (bind(sock, (sockaddr*)&address, sizeof(sockaddr_in)) < 0)
        {
                DDrStartupMessage("could not bind port %d", port);
                return false;
        }
        
        unsigned long nonBlocking = 1;
        if (ioctlsocket(sock, FIONBIO, &nonBlocking))
        {
                DDrStartupMessage("failed to set non-blocking socket");
                return false;
        }
        
        return sock;
}

bool Net_Send(int socket, int ip, uint16_t port, char* data, int datalen)
{
        sockaddr_in address;
        memset(&address, 0, sizeof(sockaddr_in));
        address.sin_family = AF_INET;
        address.sin_addr.s_addr = ip;
        address.sin_port = htons(port);
        
        return sendto(socket, data, datalen, 0, (sockaddr*)&address, sizeof(address));
}

void Net_CloseSocket(int sock)
{
        closesocket(sock);
}

bool FLrListen_PacketCallback(char* data, int datalen, int from)
{
        static int recieved = 0;
        
        data[datalen] = '\0';
        if (!strcmp(data, "hi"))
                printf("\r%d packets recieved                                ", ++recieved);
        return true;
}

bool FLrListen_Run()
{
        return Net_Listen(27777, FLrListen_PacketCallback);
}