client.c

#include <assert.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <string.h>
#include <netinet/in.h>
#include <stdio.h>
#include <arpa/inet.h>

#define PACKETLEN 1500
#define BUFLEN 100

typedef struct header_s {
    short magicnum;
    char version;
    char packet_type;
    short header_len;
    short packet_len; 
    u_int seq_num;
    u_int ack_num;
} header_t;  

typedef struct data_packet {
    header_t header;
    char data[BUFLEN];
} data_packet_t;


int main(int argc, char **argv) {
    int fd = socket(AF_INET, SOCK_DGRAM, 0);
    struct sockaddr_in myaddr, toaddr;
    socklen_t fromlen;
    char buf[BUFLEN];

    data_packet_t packet;

    assert(fd != 0);
    if (argc < 4) {
        printf("usage: %s <node id> <my port> <to port> <magic number>\n", argv[0]);
        return 1;
    }

    bzero(&myaddr, sizeof(myaddr));
    myaddr.sin_family = AF_INET;
    inet_aton("127.0.0.1", &myaddr.sin_addr);
    myaddr.sin_port = htons(atoi(argv[2]));
    assert(bind(fd, (struct sockaddr *) &myaddr, sizeof(myaddr)) >= 0);

    /* init spiffy */
    spiffy_init(atoi(argv[1]), &myaddr, sizeof(myaddr));

    inet_aton("127.0.0.1", &toaddr.sin_addr);
    toaddr.sin_port = htons(atoi(argv[3]));
    toaddr.sin_family = AF_INET;
    
    packet.header.magicnum = htons(atoi(argv[4]));
    memset(&(packet.data), 0, BUFLEN);  

    spiffy_sendto(fd, &packet, sizeof(data_packet_t), 0, (struct sockaddr *) &toaddr, sizeof(toaddr));

    printf("Sent MAGIC: %d\n", atoi(argv[4]));

    return 0;
}