/*
 * $Id: ping.c,v 1.5 1999/12/09 06:11:36 andersen Exp $
 * Mini ping implementation for busybox
 *
 * Copyright (C) 1999 by Randolph Chung <tausq@debian.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 * This version of ping is adapted from the ping in netkit-base 0.10,
 * which is:
 *
 * Copyright (c) 1989 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Mike Muuss.
 * 
 * Original copyright notice is retained at the end of this file.
 */

#include "internal.h"
#include <sys/param.h>
#include <sys/socket.h>
#include <sys/file.h>
#include <sys/time.h>
#include <sys/times.h>
#include <sys/signal.h>

#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/ip_icmp.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>

#define DEFDATALEN      56
#define	MAXIPLEN	60
#define	MAXICMPLEN	76
#define	MAXPACKET	65468
#define	MAX_DUP_CHK	(8 * 128)
#define MAXWAIT         10
#define PINGINTERVAL    1 /* second */

#define O_QUIET         (1 << 0)

#define	A(bit)		rcvd_tbl[(bit)>>3]	/* identify byte in array */
#define	B(bit)		(1 << ((bit) & 0x07))	/* identify bit in byte */
#define	SET(bit)	(A(bit) |= B(bit))
#define	CLR(bit)	(A(bit) &= (~B(bit)))
#define	TST(bit)	(A(bit) & B(bit))

static const char* ping_usage = "ping [OPTION]... host\n\n"
"Send ICMP ECHO_REQUEST packets to network hosts.\n\n"
"Options:\n"
"\t-q\t\tQuiet mode, only displays output at start and when finished.\n"
"\t-c COUNT\tSend only COUNT pings.\n";

static char *hostname = NULL;
static struct sockaddr_in pingaddr;
static int pingsock = -1;
static long ntransmitted = 0, nreceived = 0, nrepeats = 0, pingcount = 0;
static int myid = 0, options = 0;
static unsigned long tmin = ULONG_MAX, tmax = 0, tsum = 0;
static char rcvd_tbl[MAX_DUP_CHK / 8];

static void pingstats(int);
static void sendping(int);
static void unpack(char *, int, struct sockaddr_in *);
static void ping(char *);
static int in_cksum(unsigned short *, int);

/**************************************************************************/

static int in_cksum(unsigned short *buf, int sz)
{
    int nleft = sz;
    int sum = 0;
    unsigned short *w = buf;
    unsigned short ans = 0;

    while (nleft > 1) {
        sum += *w++;
        nleft -= 2;
    }

    if (nleft == 1) { 
        *(unsigned char *)(&ans) = *(unsigned char *)w;
        sum += ans;
    }

    sum = (sum >> 16) + (sum & 0xFFFF);
    sum += (sum >> 16);
    ans = ~sum;
    return(ans);
}   

static void pingstats(int ign) {
    signal(SIGINT, SIG_IGN);
    
    printf("\n--- %s ping statistics ---\n", hostname);
    printf("%ld packets transmitted, ", ntransmitted);
    printf("%ld packets received, ", nreceived);
    if (nrepeats)
        printf("%ld duplicates, ", nrepeats);
    if (ntransmitted)
	printf("%ld%% packet loss\n", 
	       (ntransmitted - nreceived)*100/ntransmitted);
    if (nreceived)
        printf("round-trip min/avg/max = %lu.%lu/%lu.%lu/%lu.%lu ms\n",
	       tmin/10, tmin%10, 
	       (tsum/(nreceived+nrepeats))/10,
	       (tsum/(nreceived+nrepeats))%10,
	       tmax/10, tmax%10);
    exit(0);
}

static void sendping(int ign)
{
    struct icmp *pkt;
    int i;
    char packet[DEFDATALEN + 8];

    pkt = (struct icmp *)packet;
    
    pkt->icmp_type = ICMP_ECHO;
    pkt->icmp_code = 0;
    pkt->icmp_cksum = 0;
    pkt->icmp_seq = ntransmitted++;
    pkt->icmp_id = myid; 
    CLR(pkt->icmp_seq % MAX_DUP_CHK);

    gettimeofday((struct timeval *)&packet[8], NULL);
    pkt->icmp_cksum = in_cksum((unsigned short *)pkt, sizeof(packet));
    
    i = sendto(pingsock, packet, sizeof(packet), 0, 
	       (struct sockaddr *)&pingaddr, sizeof(struct sockaddr_in));

    if (i < 0 || i != sizeof(packet)) {
        if (i < 0) perror("ping");
        fprintf(stderr, "ping wrote %d chars; %d expected\n", i, sizeof(packet));
	exit(1);
    }

    signal(SIGALRM, sendping);
    if (pingcount == 0 || ntransmitted < pingcount) { /* schedule next in 1s */
        alarm(PINGINTERVAL);
    } else { /* done, wait for the last ping to come back */
	/* todo, don't necessarily need to wait so long... */
        signal(SIGALRM, pingstats);
	alarm(MAXWAIT);
    }
}
    
static void unpack(char *buf, int sz, struct sockaddr_in *from)
{
    struct icmp *icmppkt;
    struct iphdr *iphdr;
    struct timeval tv, *tp;
    int hlen, dupflag;
    unsigned long triptime;
    
    gettimeofday(&tv, NULL);
    
    /* check IP header */
    iphdr = (struct iphdr *)buf;
    hlen = iphdr->ihl << 2;
    /* discard if too short */
    if (sz < (DEFDATALEN + ICMP_MINLEN)) return;

    sz -= hlen;
    icmppkt = (struct icmp *)(buf + hlen);
    
    if (icmppkt->icmp_type == ICMP_ECHOREPLY) {
        if (icmppkt->icmp_id != myid) return; /* not our ping */
	++nreceived;
	tp = (struct timeval *)icmppkt->icmp_data;

	if ((tv.tv_usec -= tp->tv_usec) < 0) {
	    --tv.tv_sec;
	    tv.tv_usec += 1000000;
	}
	tv.tv_sec -= tp->tv_sec;
	
	triptime = tv.tv_sec * 10000 + (tv.tv_usec / 100);
	tsum += triptime;
	if (triptime < tmin) tmin = triptime;
	if (triptime > tmax) tmax = triptime;

	if (TST(icmppkt->icmp_seq % MAX_DUP_CHK)) {
	    ++nrepeats;
	    --nreceived;
	    dupflag = 1;
	} else {
	    SET(icmppkt->icmp_seq % MAX_DUP_CHK);
	    dupflag = 0;
	}

	if (options & O_QUIET) return;

	printf("%d bytes from %s: icmp_seq=%u", sz, 
	       inet_ntoa(*(struct in_addr *)&from->sin_addr.s_addr),
	       icmppkt->icmp_seq);
	printf(" ttl=%d", iphdr->ttl);
	printf(" time=%lu.%lu ms", triptime/10, triptime%10);
	if (dupflag) printf(" (DUP!)");
        printf("\n");
    } else {
        fprintf(stderr, "Warning: unknown ICMP packet received (not echo-reply)\n");
    }	
}

static void ping(char *host)
{
    struct protoent *proto;
    struct hostent *h;
    char buf[MAXHOSTNAMELEN];
    char packet[DEFDATALEN + MAXIPLEN + MAXICMPLEN];
    int sockopt;
    
    if (!(proto = getprotobyname("icmp"))) {
        fprintf(stderr, "ping: unknown protocol icmp\n");
	exit(1);
    }
    if ((pingsock = socket(AF_INET, SOCK_RAW, proto->p_proto)) < 0) {
	if (errno == EPERM) {
	    fprintf(stderr, "ping: permission denied. (are you root?)\n");
	} else {
	    perror("ping");
	}
	exit(1);
    }

    /* drop root privs if running setuid */
    setuid(getuid());
    
    memset(&pingaddr, 0, sizeof(struct sockaddr_in));
    pingaddr.sin_family = AF_INET;
    if (inet_aton(host, &pingaddr.sin_addr)) {
        hostname = host;
    } else {    
        if (!(h = gethostbyname(host))) {
            fprintf(stderr, "ping: unknown host %s\n", host);
	    exit(1);
        }

	if (h->h_addrtype != AF_INET) {
	    fprintf(stderr, "ping: unknown address type; only AF_INET is currently supported.\n");
	    exit(1);
	}
	
	pingaddr.sin_family = AF_INET; /* h->h_addrtype */
        memcpy(&pingaddr.sin_addr, h->h_addr, sizeof(pingaddr.sin_addr)); 
        strncpy(buf, h->h_name, sizeof(buf)-1);
	hostname = buf;
    }

    /* enable broadcast pings */
    sockopt = 1;
    setsockopt(pingsock, SOL_SOCKET, SO_BROADCAST, (char *)&sockopt, sizeof(sockopt));
    
    /* set recv buf for broadcast pings */
    sockopt = 48 * 1024;
    setsockopt(pingsock, SOL_SOCKET, SO_RCVBUF, (char *)&sockopt, sizeof(sockopt));

    printf("PING %s (%s): %d data bytes\n", 
           hostname, inet_ntoa(*(struct in_addr *)&pingaddr.sin_addr.s_addr),
	   DEFDATALEN);

    signal(SIGINT, pingstats);
    
    /* start the ping's going ... */
    sendping(0);
	
    /* listen for replies */
    while (1) {
        struct sockaddr_in from;
	size_t fromlen = sizeof(from);
        int c;

        if ((c = recvfrom(pingsock, packet, sizeof(packet), 0,
                          (struct sockaddr *)&from, &fromlen)) < 0) {
            if (errno == EINTR) continue;
	    perror("ping");
	    continue;
	}
	unpack(packet, c, &from);
	if (pingcount > 0 && nreceived >= pingcount) break;	
    }
    pingstats(0);
}

extern int ping_main(int argc, char **argv)
{
    char *thisarg;
    
    argc--;
    argv++;
    options = 0;
    /* Parse any options */
    while (argc > 1) {
        if (**argv != '-') usage(ping_usage);
        thisarg = *argv; thisarg++;
        switch (*thisarg) {
	    case 'q': options |= O_QUIET; break;
 	    case 'c':
	        argc--; argv++;
	        pingcount = atoi(*argv);	        
	        break;
  	    default:
	        usage(ping_usage);
        }
        argc--; argv++;
    }
    if (argc < 1) usage(ping_usage);       

    myid = getpid() & 0xFFFF;
    ping(*argv);
    exit(TRUE);
}

/*
 * Copyright (c) 1989 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Mike Muuss.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */