socket.c

#include <netdb.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <pthread.h>
#include "../defines.h"
#include "socket.h"

void *receive_loop(void *ptr) {
    char bufin[MAX_PAYLOAD_LENGTH];

    prrt_socket *sock_ptr = ptr;

    while(1) {
        memset(bufin, 0, MAX_PAYLOAD_LENGTH);
        prrt_packet *t = prrt_recv_feedback(sock_ptr, bufin, MAX_PAYLOAD_LENGTH);
        if(t != NULL) {
            delete_packet(t);
        }
        usleep(1000);
    }
}

int prrt_create_socket(prrt_socket *sock_ptr, uint16_t port, uint8_t is_sender) {
    // Create Data Socket
    if((sock_ptr->fd_data = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
        perror("cannot create socket");
        return -1;
    }

    // Bind Data Socket
    struct sockaddr_in address;
    memset((char*) &address, 0, sizeof(address));
    address.sin_family = AF_INET;
    address.sin_addr.s_addr = htonl(INADDR_ANY);
    address.sin_port = htons(port);

    if(bind(sock_ptr->fd_data, (struct sockaddr *) &address, sizeof(address)) < 0) {
        perror("cannot bind socket");
        return -1;
    }

    // Create Feedback Socket
    if((sock_ptr->fd_feedback = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
        perror("cannot create socket");
        return -1;
    }

    // Bind Feedback Socket
    memset((char*) &address, 0, sizeof(address));
    address.sin_family = AF_INET;
    address.sin_addr.s_addr = htonl(INADDR_ANY);
    address.sin_port = htons((uint16_t) (port + 1)); // TODO: fail if port is 65535

    if(bind(sock_ptr->fd_feedback, (struct sockaddr *) &address, sizeof(address)) < 0) {
        perror("cannot bind socket");
        return -1;
    }

    if(is_sender) {
        int rc = pthread_create(&sock_ptr->receive_thread, NULL, receive_loop, (void*) sock_ptr);
        if(rc) {
            printf("ERROR; return code from pthread_create() is %d\n", rc);
            exit(-1);
        }

    } else {

    }

    return 0;
}

int prrt_connect(prrt_socket *sock_ptr, char *host, uint16_t port) {
    prrt_receiver recv =  { host , port};

    if(sock_ptr->receiver_len < PRRT_MAX_RECEIVER_COUNT) {
        sock_ptr->receivers[sock_ptr->receiver_len] =recv;
        sock_ptr->receiver_len++;
    } else {
        return -1;
    }

    return 0;
}

int prrt_send(prrt_socket *sock_ptr, const void *data, size_t data_len) {
    int res = 0;
    prrt_packet* packet = malloc(sizeof(prrt_packet));
    create_packet_data(packet, 5, data, data_len);

    uint8_t buf[MAX_PAYLOAD_LENGTH];
    uint32_t length = packet_size(packet);
    if(encode_packet(buf, MAX_PAYLOAD_LENGTH, packet) < 0) {
        perror("BUF too small.");
        return -1;
    }

    // SENDING TO ALL RECEIVERS
    int i;
    for(i = 0; i < sock_ptr->receiver_len; i++) {
        prrt_receiver recv = sock_ptr->receivers[i];

        struct hostent *hp;

        struct sockaddr_in targetaddr;
        memset((char*) &targetaddr, 0, sizeof(targetaddr));
        targetaddr.sin_family = AF_INET;
        targetaddr.sin_port = htons(recv.port);

        hp = gethostbyname(recv.host_name);
        memcpy((void *)&targetaddr.sin_addr, hp->h_addr_list[0], (size_t) hp->h_length);

        if((sendto(sock_ptr->fd_data, buf, length, 0, (struct sockaddr *) &targetaddr, sizeof(targetaddr)) < 0)) {
            perror("sendto failed");
            res = -1;
            break;
        }
    }
    delete_packet(packet);
    return res;
}

prrt_packet *prrt_recv(prrt_socket *sock_ptr) {
    unsigned char buffer[MAX_PAYLOAD_LENGTH];

    // RECEIVE DATA
    ssize_t n;
    struct sockaddr_in remote;
    socklen_t addrlen = sizeof(remote);

    n = recvfrom(sock_ptr->fd_data, buffer, MAX_PAYLOAD_LENGTH, 0, (struct sockaddr *) &remote, &addrlen);
    uint16_t remote_port = ntohs(remote.sin_port);
    char *remote_host = inet_ntoa(remote.sin_addr);

    prrt_packet *packet = malloc(sizeof(prrt_packet));
    decode_packet(buffer, (uint16_t) n, packet);

    // REPLY
    struct sockaddr_in targetaddr;
    memset((char*) &targetaddr, 0, sizeof(targetaddr));
    targetaddr.sin_family = AF_INET;
    targetaddr.sin_port = htons((uint16_t) (remote_port + 1));

    struct hostent *hp;
    hp = gethostbyname(remote_host);
    memcpy((void *)&targetaddr.sin_addr, hp->h_addr_list[0], (size_t) hp->h_length);

    prrt_packet* feedback_pkt_ptr = create_packet_feedback(0, 19, 4715, 7, 3, 50, 4, 6, 8, 9, 5, 1);
    uint8_t buf[MAX_PAYLOAD_LENGTH];
    uint32_t length = packet_size(feedback_pkt_ptr);

    if(encode_packet(buf, MAX_PAYLOAD_LENGTH, feedback_pkt_ptr) < 0) {
        perror("BUF too small.");
    } else {
        if((sendto(sock_ptr->fd_feedback, buf, length, 0, (struct sockaddr *) &targetaddr, sizeof(targetaddr)) < 0)) {
            perror("sendto failed");
            return NULL;
        }

    }
    return packet;
}

int prrt_close_socket(prrt_socket *sock_ptr) {
    // TODO: shut down threads;

    // TODO: clean up all receivers

    close(sock_ptr->fd_data);
    close(sock_ptr->fd_feedback);
    return 0;
}

prrt_packet * prrt_recv_feedback(prrt_socket *sock_ptr, void *bufin, size_t length) {
    ssize_t n;
    struct sockaddr_in remote;
    socklen_t addrlen = sizeof(remote);

    n = recvfrom(sock_ptr->fd_feedback, bufin, length, 0, (struct sockaddr *) &remote, &addrlen);
    if(n < 0) {
        perror("RECVFROM FAIL");
        return NULL;
    }
    uint16_t remote_port = ntohs(remote.sin_port);
    char *remote_host = inet_ntoa(remote.sin_addr);
    printf("RECV FEEDBACK: %s:%d\n", remote_host, remote_port);

    prrt_packet * packet_ptr = malloc(sizeof(prrt_packet));
    decode_packet(bufin, (uint16_t) n, packet_ptr);
    return packet_ptr;
}