/* io.c 		All base I/O routines live here
 *
 * Copyright 1991, Michael Westerhof, Sun Microsystems, Inc.
 * This software may be freely used, distributed, or modified, providing
 * this header is not removed.
 *
 * This is the only module that knows about base level UNIX/SunOS I/O
 * This is also the key dispatching module, so it knows about a lot more
 * than just I/O stuff.
 */

#undef USE_ICMP			/* not implemented yet, sorry */

#include "ax25ipd.h"

#include <sys/types.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#ifdef USE_ICMP
#include <netinet/ip_icmp.h>
#endif
#include <netdb.h>
#include <fcntl.h>
#include <memory.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>

#ifdef __bsdi__
#define USE_TERMIOS
#endif

#ifndef USE_TERMIOS
#ifndef USE_TERMIO
#define USE_SGTTY
#endif
#endif

#ifdef USE_TERMIOS
#include <sys/termios.h>
struct termios nterm;
#endif

#ifdef USE_TERMIO
#include <termio.h>
struct termio  nterm;
#endif

#ifdef USE_SGTTY
#include <sys/ioctl.h>
struct sgttyb  nterm;
#endif

int ttyfd = -1;
int udpsock = -1;
int sock = -1;
#ifdef USE_ICMP
int icmpsock = -1;
#endif
struct sockaddr_in udpbind;
struct sockaddr_in to;
struct sockaddr_in from;
int fromlen;

time_t last_bc_time;

/*
 * I/O modes for the io_error routine
 */
#define READ_MSG	0x00
#define SEND_MSG	0x01

#define IP_MODE		0x10
#define UDP_MODE	0x20
#define TTY_MODE	0x30
#ifdef USE_ICMP
#define ICMP_MODE	0x40
#endif

#ifndef FNDELAY
#define FNDELAY O_NDELAY
#endif

/*
 * Initialize the io variables
 */

void
io_init()
{

/*
 * Close the file descriptors if they are open.  The idea is that we
 * will be able to support a re-initialization if sent a SIGHUP.
 */

	if(ttyfd>=0){
		close(ttyfd);
		ttyfd = -1;
	}

	if(sock>=0){
		close(sock);
		sock = -1;
	}

	if(udpsock>=0){
		close(udpsock);
		udpsock = -1;
	}

#ifdef USE_ICMP
	if(icmpsock>=0){
		close(icmpsock);
		icmpsock = -1;
	}
#endif

/*
 * The bzero is not strictly required - it simply zeros out the
 * address structure.  Since both to and from are static, they are
 * already clear.
 */
	bzero( (char *)&to, sizeof(struct sockaddr) );
	to.sin_family = AF_INET;

	bzero( (char *)&from, sizeof(struct sockaddr) );
	from.sin_family = AF_INET;

	bzero( (char *)&udpbind, sizeof(struct sockaddr) );
	udpbind.sin_family = AF_INET;
}

/*
 * open and initialize the IO interfaces
 */

void io_open()
{
	int baudrate;

	if(ip_mode){
		sock = socket(AF_INET, SOCK_RAW, IPPROTO_AX25);
		if (sock<0) {
			perror("opening raw socket");
			exit(1);
		}
		if (fcntl(sock, F_SETFL, FNDELAY) < 0) {
			perror("setting non-blocking I/O on raw socket");
			exit(1);
		}

#ifdef USE_ICMP
		icmpsock = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
		if (icmpsock<0) {
			perror("opening raw ICMP socket");
			exit(1);
		}
		if (fcntl(icmpsock, F_SETFL, FNDELAY) < 0) {
			perror("setting non-blocking I/O on ICMP socket");
			exit(1);
		}
#endif
	}

	if(udp_mode){
		udpsock = socket(AF_INET, SOCK_DGRAM, 0);
		if (udpsock<0) {
			perror("opening udp socket");
			exit(1);
		}
		if (fcntl(udpsock, F_SETFL, FNDELAY) < 0) {
			perror("setting non-blocking I/O on UDP socket");
			exit(1);
		}
/*
 * Ok, the udp socket is open.  Now express our interest in receiving
 * data destined for a particular socket.
 */
		udpbind.sin_addr.s_addr = INADDR_ANY;
		udpbind.sin_port = my_udp;
		if(bind(udpsock,(struct sockaddr *)&udpbind,sizeof udpbind)<0){
			perror("binding udp socket");
			exit(1);
		}
	}

	ttyfd = open(ttydevice, O_RDWR, 0);
	if (ttyfd<0) {
		perror("opening tty device");
		exit(1);
	}
	if (fcntl(ttyfd, F_SETFL, FNDELAY) < 0) {
		perror("setting non-blocking I/O on tty device");
		exit(1);
	}

#ifdef USE_TERMIOS
	if(ioctl(ttyfd, TCGETS, &nterm)<0){
#endif
#ifdef USE_TERMIO
	if(ioctl(ttyfd, TCGETA, &nterm)<0){
#endif
#ifdef USE_SGTTY
	if(ioctl(ttyfd, TIOCGETP, &nterm)<0){
#endif
		perror("fetching tty device parameters");
		exit(1);
	}

	if(ttyspeed==50)baudrate=B50;
	else if(ttyspeed==50)baudrate=B50;
	else if(ttyspeed==75)baudrate=B75;
	else if(ttyspeed==110)baudrate=B110;
	else if(ttyspeed==134)baudrate=B134;
	else if(ttyspeed==150)baudrate=B150;
	else if(ttyspeed==200)baudrate=B200;
	else if(ttyspeed==300)baudrate=B300;
	else if(ttyspeed==600)baudrate=B600;
	else if(ttyspeed==1200)baudrate=B1200;
	else if(ttyspeed==1800)baudrate=B1800;
	else if(ttyspeed==2400)baudrate=B2400;
	else if(ttyspeed==4800)baudrate=B4800;
	else if(ttyspeed==9600)baudrate=B9600;
#ifdef B19200
	else if(ttyspeed==19200)baudrate=B19200;
#else
#ifdef EXTA
	else if(ttyspeed==19200)baudrate=EXTA;
#endif
#endif
#ifdef B38400
	else if(ttyspeed==38400)baudrate=B38400;
#else
#ifdef EXTB
	else if(ttyspeed==38400)baudrate=EXTB;
#endif
#endif
	else baudrate = B9600;

#ifdef USE_SGTTY
	nterm.sg_flags = (RAW | ANYP);
	nterm.sg_ispeed = baudrate;
	nterm.sg_ospeed = baudrate;
#else
        nterm.c_iflag = 0;
        nterm.c_oflag = 0;
	nterm.c_cflag = baudrate | CS8 | CREAD | CLOCAL;
	nterm.c_lflag = 0;
        nterm.c_cc[VMIN] = 0;
        nterm.c_cc[VTIME] = 0;
#endif

#ifdef USE_TERMIOS
	if(ioctl(ttyfd, TCSETS, &nterm)<0){
#endif
#ifdef USE_TERMIO
	if(ioctl(ttyfd, TCSETA, &nterm)<0){
#endif
#ifdef USE_SGTTY
	if(ioctl(ttyfd, TIOCSETP, &nterm)<0){
#endif
		perror("setting tty device parameters");
		exit(1);
	}

	if(digi)send_params();

	last_bc_time = 0;	/* force immediate id */
}

/*
 * Start up and run the I/O mechanisms.
 *  run in a loop, using the select call to handle input.
 */

void
io_start()
{
	int n, nb, hdr_len;
	fd_set readfds;
	unsigned char buf[MAX_FRAME];
	struct timeval wait;
	struct iphdr *ipptr;
	time_t now;

	for(;;){

		if((bc_interval>0)&&digi){
			now = time(NULL);
			if (last_bc_time + bc_interval < now){
				last_bc_time = now;
				LOGL4("iostart: BEACON\n");
				do_beacon();
			}
		}

		wait.tv_sec =  10;	/* lets us keep the beacon going */
		wait.tv_usec = 0;

		FD_ZERO(&readfds);

		FD_SET(ttyfd, &readfds);

		if(ip_mode){
			FD_SET(sock, &readfds);
#ifdef USE_ICMP
			FD_SET(icmpsock, &readfds);
#endif
		}

		if(udp_mode){
			FD_SET(udpsock, &readfds);
		}

		nb = select(FD_SETSIZE,&readfds,(fd_set *)0,(fd_set *)0,&wait);

		if(nb < 0){
			if(errno == EINTR)continue;	/* Ignore */
			perror("select");
			exit(1);
		}

		if(nb == 0){
			fflush(stdout);
			fflush(stderr);
			/* just so we go back to the top of the loop! */
			continue;
		}

		if(FD_ISSET(ttyfd, &readfds)){
			do {
				n = read(ttyfd, buf, MAX_FRAME);
			} while(io_error(n, buf, n, READ_MSG, TTY_MODE));
			LOGL4("ttydata l=%d\n",n);
			if(n>0)assemble_kiss(buf,n);
/*
 * If we are in "beacon after" mode, reset the "last_bc_time" each time
 * we hear something on the channel.
 */
			if(!bc_every)last_bc_time = time(NULL);
		}

		if(udp_mode){
			if(FD_ISSET(udpsock, &readfds)){
				do {
					fromlen = sizeof from;
					n = recvfrom(udpsock, buf, MAX_FRAME, 0,
						(struct sockaddr *)&from, &fromlen);
				} while(io_error(n, buf, n, READ_MSG, UDP_MODE));
				LOGL4("udpdata from=%s port=%d l=%d\n",
					(char *)inet_ntoa(from.sin_addr),
					ntohs(from.sin_port), n);
				stats.udp_in++;
				if(n>0)from_ip(buf, n);
			}
		} /* if udp_mode */

		if(ip_mode){
			if(FD_ISSET(sock, &readfds)){
				do{
					fromlen = sizeof from;
					n = recvfrom(sock, buf, MAX_FRAME, 0,
						(struct sockaddr *)&from, &fromlen);
				} while(io_error(n, buf, n, READ_MSG, IP_MODE));
				ipptr = (struct iphdr *)buf;
				hdr_len = 4 * ipptr->ihl;
				LOGL4("ipdata from=%s l=%d, hl=%d\n",
					(char *)inet_ntoa(from.sin_addr),
					n, hdr_len);
				stats.ip_in++;
				if(n>hdr_len)from_ip(buf+hdr_len, n-hdr_len);
			}

#ifdef USE_ICMP
			if(FD_ISSET(icmpsock, &readfds)){
				do {
					fromlen = sizeof from;
					n = recvfrom(icmpsock, buf, MAX_FRAME, 0,
						(struct sockaddr *)&from, &fromlen);
				} while(io_error(n, buf, n, READ_MSG, ICMP_MODE));
				ipptr = (struct iphdr *)buf;
				hdr_len = 4 * ipptr->ihl;
				LOGL4("icmpdata from=%s l=%d, hl=%d\n",
					(char *)inet_ntoa(from.sin_addr),
					n, hdr_len);
			}
#endif
		} /* if ip_mode */

	} /* for forever */
}

/* Send an IP frame */

void
send_ip(buf, l, targetip)
unsigned char *buf;
int l;
unsigned char *targetip;
{
	int n;

	if(l<=0)return;
	memcpy((char *)&to.sin_addr, targetip, 4);
	memcpy((char *)&to.sin_port, &targetip[4], 2);
	LOGL4("sendipdata to=%s %s %d l=%d\n",
			(char *)inet_ntoa(to.sin_addr),
			to.sin_port ? "udp" : "ip",
			ntohs(to.sin_port), l);
	if(to.sin_port){
		if(udp_mode){
			stats.udp_out++;
			do {
				n = sendto(udpsock, buf, l, 0,
					(struct sockaddr *)&to, sizeof to);
			} while(io_error(n, buf, l, SEND_MSG, UDP_MODE));
		}
	} else {
		if(ip_mode){
			stats.ip_out++;
			do {
				n = sendto(sock, buf, l, 0,
					(struct sockaddr *)&to, sizeof to);
			} while(io_error(n, buf, l, SEND_MSG, IP_MODE));
		}
	}
}

/* Send a kiss frame */

void
send_tty(buf, l)
unsigned char *buf;
int l;
{
	int n;
	unsigned char *p;
	int nc;

	if(l<=0)return;
	LOGL4("sendttydata l=%d\tsent: ",l);
	stats.kiss_out++;

	p = buf;
	nc = l;
	n = 0;

/*
 * we have to loop around here because each call to write may write a few
 * characters.  So we simply increment the buffer each time around.  If
 * we ever write no characters, we should get an error code, and io_error
 * will sleep for a fraction of a second.  Note that we are keyed to
 * the BSD 4.2 behaviour... the Sys 5 non-blocking I/O may or may not work
 * in this loop.  We may detect system 5 behaviour (this would result from
 * compile-time options) by having io_error barf when it detects an EAGAIN
 * error code.
 */
	do {
		if((n>0)&&(n<nc)) {	/* did we put only write a bit? */
			p += n;			/* point to the new data */
			nc -= n;		/* drop the length */
		}
		n = write(ttyfd, p, nc);
		if(n>0){
			if(n!=nc){
				LOGL4("%d ",n);  /* no-one said loglevel 4 */
			} else {
				LOGL4("%d\n",n);     /* was efficient!!! */
			}
		}
	} while( ((n>0)&&(n<nc)) || (io_error(n, p, nc, SEND_MSG, TTY_MODE)));
}

/* process an I/O error; return true if a retry is needed */
int
io_error(oops, buf, bufsize, dir, mode)
int oops;			/* the error flag; < 0 indicates a problem */
unsigned char *buf;		/* the data in question */
int bufsize;			/* the size of the data buffer */
int dir;			/* the direction; input or output */
int mode;			/* the fd on which we got the error */
{

	if(oops >= 0) return 0;	/* do we have an error ? */

#ifdef EAGAIN
	if(errno == EAGAIN){
		perror("System 5 I/O error!");
		fprintf(stderr,"A System 5 style I/O error was detected.  This program requires BSD 4.2\n");
		fprintf(stderr,"behaviour.  This is probably a result of compile-time environment.\n");
		exit(3);
	}
#endif

	if(dir == READ_MSG){
		if(errno == EINTR) return 0;	/* never retry read */
		if(errno == EWOULDBLOCK){
			LOGL4("READ would block (?!), sleeping and retrying!\n");
			usleep(100000);	/* sleep a bit */
			return 1;		/* and retry */
		}
		if(mode == IP_MODE){
			perror("reading from raw ip socket");
			exit(2);
		} else if(mode == UDP_MODE){
			perror("reading from udp socket");
			exit(2);
		} else if(mode == TTY_MODE){
			perror("reading from tty device");
			exit(2);
		} else {
			perror("reading from unknown I/O");
			exit(2);
		}
	} else if(dir == SEND_MSG){
		if(errno == EINTR) return 1;	/* always retry on writes */
		if(mode == IP_MODE){
			if(errno == EMSGSIZE){	/* msg too big, drop it */
				perror("message dropped on raw ip socket");
				fprintf(stderr,"message was %d bytes long.\n",bufsize);
				return 0;
			}
			if(errno == ENOBUFS){	/* congestion; sleep + retry */
				LOGL4("send congestion on raw ip, sleeping and retrying!\n");
				usleep(100000);
				return 1;
			}
			if(errno == EWOULDBLOCK){
				LOGL4("send on raw ip would block, sleeping and retrying!\n");
				usleep(100000);	/* sleep a bit */
				return 1;		/* and retry */
			}
			perror("writing to raw ip socket");
			exit(2);
		} else if(mode == UDP_MODE){
			if(errno == EMSGSIZE){	/* msg too big, drop it */
				perror("message dropped on udp socket");
				fprintf(stderr,"message was %d bytes long.\n",bufsize);
				return 0;
			}
			if(errno == ENOBUFS){	/* congestion; sleep + retry */
				LOGL4("send congestion on udp, sleeping and retrying!\n");
				usleep(100000);
				return 1;
			}
			if(errno == EWOULDBLOCK){
				LOGL4("send on udp would block, sleeping and retrying!\n");
				usleep(100000);	/* sleep a bit */
				return 1;		/* and retry */
			}
			perror("writing to udp socket");
			exit(2);
		} else if(mode == TTY_MODE){
			if(errno == EWOULDBLOCK){
				LOGL4("write to tty would block, sleeping and retrying!\n");
				usleep(100000);	/* sleep a bit */
				return 1;		/* and retry */
			}
			perror("writing to tty device");
			exit(2);
		} else {
			perror("writing to unknown I/O");
			exit(2);
		}
	} else {
		perror("Unknown direction and I/O");
		exit(2);
	}
	return 0;
}