ping.c

linux下网络编程

			(void)printf("\nNOP");
			break;
		default:
			(void)printf("\nunknown option %x", *cp);
			break;
		}
/*#endif*/
	if (!(options & F_FLOOD)) {
		(void)putchar('\n');
		(void)fflush(stdout);
	}
}

/*
 * in_cksum --
 *	Checksum routine for Internet Protocol family headers (C Version)
 */
static int
in_cksum(u_short *addr, int len)
{
	register int nleft = len;
	register u_short *w = addr;
	register int sum = 0;
	u_short answer = 0;

	/*
	 * Our algorithm is simple, using a 32 bit accumulator (sum), we add
	 * sequential 16 bit words to it, and at the end, fold back all the
	 * carry bits from the top 16 bits into the lower 16 bits.
	 */
	while (nleft > 1)  {
		sum += *w++;
		nleft -= 2;
	}

	/* mop up an odd byte, if necessary */
	if (nleft == 1) {
		*(u_char *)(&answer) = *(u_char *)w ;
		sum += answer;
	}

	/* add back carry outs from top 16 bits to low 16 bits */
	sum = (sum >> 16) + (sum & 0xffff);	/* add hi 16 to low 16 */
	sum += (sum >> 16);			/* add carry */
	answer = ~sum;				/* truncate to 16 bits */
	return(answer);
}

/*
 * tvsub --
 *	Subtract 2 timeval structs:  out = out - in.  Out is assumed to
 * be >= in.
 */
static void
tvsub(register struct timeval *out, register struct timeval *in)
{
	if ((out->tv_usec -= in->tv_usec) < 0) {
		--out->tv_sec;
		out->tv_usec += 1000000;
	}
	out->tv_sec -= in->tv_sec;
}

/*
 * finish --
 *	Print out statistics, and give up.
 */
static void
finish(int ignore)
{
	(void)ignore;

	(void)signal(SIGINT, SIG_IGN);
	(void)putchar('\n');
	(void)fflush(stdout);
	(void)printf("--- %s ping statistics ---\n", hostname);
	(void)printf("%ld packets transmitted, ", ntransmitted);
	(void)printf("%ld packets received, ", nreceived);
	if (nrepeats)
		(void)printf("+%ld duplicates, ", nrepeats);
	if (ntransmitted)
		if (nreceived > ntransmitted)
			(void)printf("-- somebody's printing up packets!");
		else
			(void)printf("%d%% packet loss",
			    (int) (((ntransmitted - nreceived) * 100) /
			    ntransmitted));
	(void)putchar('\n');
	if (nreceived && timing)
		(void)printf("round-trip min/avg/max = %ld.%ld/%lu.%ld/%ld.%ld ms\n",
			tmin/10, tmin%10,
			(tsum / (nreceived + nrepeats))/10,
			(tsum / (nreceived + nrepeats))%10,
			tmax/10, tmax%10);

	if (nreceived==0) exit(1);
	exit(0);
}

#ifdef notdef
static char *ttab[] = {
	"Echo Reply",		/* ip + seq + udata */
	"Dest Unreachable",	/* net, host, proto, port, frag, sr + IP */
	"Source Quench",	/* IP */
	"Redirect",		/* redirect type, gateway, + IP  */
	"Echo",
	"Time Exceeded",	/* transit, frag reassem + IP */
	"Parameter Problem",	/* pointer + IP */
	"Timestamp",		/* id + seq + three timestamps */
	"Timestamp Reply",	/* " */
	"Info Request",		/* id + sq */
	"Info Reply"		/* " */
};
#endif

/*
 * pr_icmph --
 *	Print a descriptive string about an ICMP header.
 */
static void
pr_icmph(struct icmphdr *icp)
{
	switch(icp->icmp_type) {
	case ICMP_ECHOREPLY:
		(void)printf("Echo Reply\n");
		/* XXX ID + Seq + Data */
		break;
	case ICMP_DEST_UNREACH:
		switch(icp->icmp_code) {
		case ICMP_NET_UNREACH:
			(void)printf("Destination Net Unreachable\n");
			break;
		case ICMP_HOST_UNREACH:
			(void)printf("Destination Host Unreachable\n");
			break;
		case ICMP_PROT_UNREACH:
			(void)printf("Destination Protocol Unreachable\n");
			break;
		case ICMP_PORT_UNREACH:
			(void)printf("Destination Port Unreachable\n");
			break;
		case ICMP_FRAG_NEEDED:
			(void)printf("frag needed and DF set\n");
			break;
		case ICMP_SR_FAILED:
			(void)printf("Source Route Failed\n");
			break;
		case ICMP_NET_UNKNOWN:
			(void)printf("Network Unknown\n");
			break;
		case ICMP_HOST_UNKNOWN:
			(void)printf("Host Unknown\n");
			break;
		case ICMP_HOST_ISOLATED:
			(void)printf("Host Isolated\n");
			break;
		case ICMP_NET_UNR_TOS:
			printf("Destination Network Unreachable At This TOS\n");
			break;
		case ICMP_HOST_UNR_TOS:
			printf("Destination Host Unreachable At This TOS\n");
			break;
#ifdef ICMP_PKT_FILTERED
		case ICMP_PKT_FILTERED:
			(void)printf("Packet Filtered\n");
			break;
#endif
#ifdef ICMP_PREC_VIOLATION
		case ICMP_PREC_VIOLATION:
			(void)printf("Precedence Violation\n");
			break;
#endif
#ifdef ICMP_PREC_CUTOFF
		case ICMP_PREC_CUTOFF:
			(void)printf("Precedence Cutoff\n");
			break;
#endif
		default:
			(void)printf("Dest Unreachable, Unknown Code: %d\n",
			    icp->icmp_code);
			break;
		}
		/* Print returned IP header information */
#ifndef icmp_data
		pr_retip((struct iphdr *)(icp + 1));
#else
		pr_retip((struct iphdr *)icp->icmp_data);
#endif
		break;
	case ICMP_SOURCE_QUENCH:
		(void)printf("Source Quench\n");
#ifndef icmp_data
		pr_retip((struct iphdr *)(icp + 1));
#else
		pr_retip((struct iphdr *)icp->icmp_data);
#endif
		break;
	case ICMP_REDIRECT:
		switch(icp->icmp_code) {
		case ICMP_REDIR_NET:
			(void)printf("Redirect Network");
			break;
		case ICMP_REDIR_HOST:
			(void)printf("Redirect Host");
			break;
		case ICMP_REDIR_NETTOS:
			(void)printf("Redirect Type of Service and Network");
			break;
		case ICMP_REDIR_HOSTTOS:
			(void)printf("Redirect Type of Service and Host");
			break;
		default:
			(void)printf("Redirect, Bad Code: %d", icp->icmp_code);
			break;
		}
		(void)printf("(New addr: %s)\n", 
			     inet_ntoa(icp->icmp_gwaddr));
#ifndef icmp_data
		pr_retip((struct iphdr *)(icp + 1));
#else
		pr_retip((struct iphdr *)icp->icmp_data);
#endif
		break;
	case ICMP_ECHO:
		(void)printf("Echo Request\n");
		/* XXX ID + Seq + Data */
		break;
	case ICMP_TIME_EXCEEDED:
		switch(icp->icmp_code) {
		case ICMP_EXC_TTL:
			(void)printf("Time to live exceeded\n");
			break;
		case ICMP_EXC_FRAGTIME:
			(void)printf("Frag reassembly time exceeded\n");
			break;
		default:
			(void)printf("Time exceeded, Bad Code: %d\n",
			    icp->icmp_code);
			break;
		}
#ifndef icmp_data
		pr_retip((struct iphdr *)(icp + 1));
#else
		pr_retip((struct iphdr *)icp->icmp_data);
#endif
		break;
	case ICMP_PARAMETERPROB:
		(void)printf("Parameter problem: IP address = %s\n",
			inet_ntoa (icp->icmp_gwaddr));
#ifndef icmp_data
		pr_retip((struct iphdr *)(icp + 1));
#else
		pr_retip((struct iphdr *)icp->icmp_data);
#endif
		break;
	case ICMP_TIMESTAMP:
		(void)printf("Timestamp\n");
		/* XXX ID + Seq + 3 timestamps */
		break;
	case ICMP_TIMESTAMPREPLY:
		(void)printf("Timestamp Reply\n");
		/* XXX ID + Seq + 3 timestamps */
		break;
	case ICMP_INFO_REQUEST:
		(void)printf("Information Request\n");
		/* XXX ID + Seq */
		break;
	case ICMP_INFO_REPLY:
		(void)printf("Information Reply\n");
		/* XXX ID + Seq */
		break;
#ifdef ICMP_MASKREQ
	case ICMP_MASKREQ:
		(void)printf("Address Mask Request\n");
		break;
#endif
#ifdef ICMP_MASKREPLY
	case ICMP_MASKREPLY:
		(void)printf("Address Mask Reply\n");
		break;
#endif
	default:
		(void)printf("Bad ICMP type: %d\n", icp->icmp_type);
	}
}

/*
 * pr_iph --
 *	Print an IP header with options.
 */
static void
pr_iph(struct iphdr *ip)
{
	int hlen;
	u_char *cp;

	hlen = ip->ip_hl << 2;
	cp = (u_char *)ip + 20;		/* point to options */

	(void)printf("Vr HL TOS  Len   ID Flg  off TTL Pro  cks      Src      Dst Data\n");
	(void)printf(" %1x  %1x  %02x %04x %04x",
	    ip->ip_v, ip->ip_hl, ip->ip_tos, ip->ip_len, ip->ip_id);
	(void)printf("   %1x %04x", ((ip->ip_off) & 0xe000) >> 13,
	    (ip->ip_off) & 0x1fff);
	(void)printf("  %02x  %02x %04x", ip->ip_ttl, ip->ip_p, ip->ip_sum);
	(void)printf(" %s ", inet_ntoa(*((struct in_addr *) &ip->ip_src)));
	(void)printf(" %s ", inet_ntoa(*((struct in_addr *) &ip->ip_dst)));
	/* dump and option bytes */
	while (hlen-- > 20) {
		(void)printf("%02x", *cp++);
	}
	(void)putchar('\n');
}

/*
 * pr_addr --
 *	Return an ascii host address as a dotted quad and optionally with
 * a hostname.
 */
static char *
pr_addr(u_long l)
{
	struct hostent *hp;
	static char buf[256];

	if ((options & F_NUMERIC) ||
	    !(hp = gethostbyaddr((char *)&l, 4, AF_INET)))
		(void)snprintf(buf, sizeof(buf), "%s", 
			       inet_ntoa(*(struct in_addr *)&l));
	else
		(void)snprintf(buf, sizeof(buf), "%s (%s)", hp->h_name,
		    inet_ntoa(*(struct in_addr *)&l));
	return(buf);
}

/*
 * pr_retip --
 *	Dump some info on a returned (via ICMP) IP packet.
 */
static void
pr_retip(struct iphdr *ip)
{
	int hlen;
	u_char *cp;

	pr_iph(ip);
	hlen = ip->ip_hl << 2;
	cp = (u_char *)ip + hlen;

	if (ip->ip_p == 6)
		(void)printf("TCP: from port %u, to port %u (decimal)\n",
		    (*cp * 256 + *(cp + 1)), (*(cp + 2) * 256 + *(cp + 3)));
	else if (ip->ip_p == 17)
		(void)printf("UDP: from port %u, to port %u (decimal)\n",
			(*cp * 256 + *(cp + 1)), (*(cp + 2) * 256 + *(cp + 3)));
}

static void
fill(void *bp1, char *patp)
{
	register int ii, jj, kk;
	int pat[16];
	char *cp, *bp = (char *)bp1;

	for (cp = patp; *cp; cp++)
		if (!isxdigit(*cp)) {
			(void)fprintf(stderr,
			    "ping: patterns must be specified as hex digits.\n");
			exit(2);
		}
	ii = sscanf(patp,
	    "%2x%2x%2x%2x%2x%2x%2x%2x%2x%2x%2x%2x%2x%2x%2x%2x",
	    &pat[0], &pat[1], &pat[2], &pat[3], &pat[4], &pat[5], &pat[6],
	    &pat[7], &pat[8], &pat[9], &pat[10], &pat[11], &pat[12],
	    &pat[13], &pat[14], &pat[15]);

	if (ii > 0)
		for (kk = 0; kk <= MAXPACKET - (8 + ii); kk += ii)
			for (jj = 0; jj < ii; ++jj)
				bp[jj + kk] = pat[jj];
	if (!(options & F_QUIET)) {
		(void)printf("PATTERN: 0x");
		for (jj = 0; jj < ii; ++jj)
			(void)printf("%02x", bp[jj] & 0xFF);
		(void)printf("\n");
	}
}

static void
usage(void)
{
	(void)fprintf(stderr,
	    "usage: ping [-LRdfnqrv] [-c count] [-i wait] [-l preload]\n\t[-p pattern] [-s packetsize] [-t ttl] [-I interface address] host\n");
	exit(2);
}