/* A simple server to attach to
*/
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <ctype.h>

#include <unistd.h>

#include <sys/types.h>

#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <netdb.h>

#define DUMP_WIDTH 16

static const char *name;

static int Socket(int p)
{
    struct sockaddr_in addr;
    int sock_fd;

    if ((sock_fd=socket(AF_INET,SOCK_STREAM,0))==-1)
    {
	perror("socket");
	exit(EXIT_FAILURE);
    }

    /* Bind port to address
    */
    addr.sin_family=AF_INET;
    addr.sin_addr.s_addr=INADDR_ANY;
    addr.sin_port=htons(p);

    if (bind(sock_fd,(void*)&addr,sizeof(addr))==-1)
    {
	perror("bind");
	exit(EXIT_FAILURE);
    }

    if (listen(sock_fd,5)==-1)
    {
	perror("listen");
	exit(EXIT_FAILURE);
    }

    return sock_fd;
}

static void Dump(const char *p, int len)
{
    char asc[DUMP_WIDTH + 1] = {0};
    unsigned int off = 0;
    int col = 0;

    while (len > 0)
    {
	unsigned char c = *p;

	if (col == 0)
	{
	    printf("%4.4x:", off);
	}

	printf(" %2.2x", (unsigned int)c);

    	asc[col++] = isprint(c) ? c : '.';

	if (col == DUMP_WIDTH)
	{
	    printf("    %s\n", asc);
	    memset(asc, 0, sizeof asc);
	    col = 0;
	}

	off++;
	p++;
	len--;
    }

    if (col > 0)
    {
	while (col++ < DUMP_WIDTH)
	{
	    printf(" **");
	}

	printf("    %s\n", asc);
    }
}

int main(int argc, char *argv[])
{
    struct sockaddr_in addr;
    char buff[1025];
    int len;
    socklen_t addrlen;
    int sock_fd;
    int connect_fd;
    int ascii = 0;

    name=argv[0];

    if (argc<2)
    {
	fprintf(stderr,"%s: usage %s port [-a]\n", name, name);
	exit(1);
    }

    ascii = (argc == 3 && strcmp(argv[2], "-a") == 0);

    sock_fd = Socket((short)atoi(argv[1]));

    printf("%s: socket bound\n",name);

    while(1)
    {
	printf("%s: accepting\n",name);

	if ((connect_fd=accept(sock_fd,NULL,0))==-1)
	{
	    perror("accept");
	    exit(1);
	}

	addrlen=sizeof(addr);

	if (getsockname(connect_fd,(void*)&addr,&addrlen)!=0)
	{
	    perror("getsockname");
	}

	printf("%s: connection ON port %d\n",name,ntohs(addr.sin_port));

	addrlen=sizeof(addr);

	if (getpeername(connect_fd,(void*)&addr,&addrlen)!=0)
	{
	    perror("getpeername");
	}

	printf("%s: connection FROM port %d\n",name,ntohs(addr.sin_port));

	while((len=read(connect_fd,buff,1024))>0)
	{
	    buff[len]=0;

            if (ascii)
            {
                printf("%s", buff);
            }
            else
            {
                printf("%s: recieved\n",name);
                Dump(buff, len);
            }
	}

	if (len == -1)
	{
	    perror("read");
	}

	close(connect_fd);
    }

    return EXIT_SUCCESS;
}