options.c

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		/*
		 * Number of bytes left to store (some may already have
		 * been stored by a previous pass).
		 */
		int length;

		/* If no data is available for this option, skip it. */
		if (!options[code]) {
			continue;
		}

		/*
		 * The client could ask for things that are mandatory,
		 * in which case we should avoid storing them twice...
		 */
		if (option_stored[code])
			continue;
		option_stored[code] = 1;

		/* We should now have a constant length for the option. */
		length = options[code]->len;

		/* Do we add a NUL? */
		if (terminate && dhcp_options[code].format[0] == 't') {
			length++;
			tto = 1;
		} else
			tto = 0;

		/* Try to store the option. */

		/*
		 * If the option's length is more than 255, we must
		 * store it in multiple hunks.   Store 255-byte hunks
		 * first.  However, in any case, if the option data will
		 * cross a buffer boundary, split it across that
		 * boundary.
		 */
		ix = 0;

		optstart = bufix;
		while (length) {
			unsigned char incr = length > 255 ? 255 : length;

			/*
			 * If this hunk of the buffer will cross a
			 * boundary, only go up to the boundary in this
			 * pass.
			 */
			if (bufix < first_cutoff &&
			    bufix + incr > first_cutoff)
				incr = first_cutoff - bufix;
			else if (bufix < second_cutoff &&
			    bufix + incr > second_cutoff)
				incr = second_cutoff - bufix;

			/*
			 * If this option is going to overflow the
			 * buffer, skip it.
			 */
			if (bufix + 2 + incr > buflen) {
				bufix = optstart;
				break;
			}

			/* Everything looks good - copy it in! */
			buffer[bufix] = code;
			buffer[bufix + 1] = incr;
			if (tto && incr == length) {
				memcpy(buffer + bufix + 2,
				    options[code]->value + ix, incr - 1);
				buffer[bufix + 2 + incr - 1] = 0;
			} else
				memcpy(buffer + bufix + 2,
				    options[code]->value + ix, incr);
			length -= incr;
			ix += incr;
			bufix += 2 + incr;
		}
	}
	return (bufix);
}

/*
 * Format the specified option so that a human can easily read it.
 */
char *
pretty_print_option(unsigned int code, unsigned char *data, int len,
    int emit_commas, int emit_quotes)
{
	static char optbuf[32768]; /* XXX */
	int hunksize = 0, numhunk = -1, numelem = 0;
	char fmtbuf[32], *op = optbuf;
	int i, j, k, opleft = sizeof(optbuf);
	unsigned char *dp = data;
	struct in_addr foo;
	char comma;

	/* Code should be between 0 and 255. */
	if (code > 255)
		error("pretty_print_option: bad code %d", code);

	if (emit_commas)
		comma = ',';
	else
		comma = ' ';

	/* Figure out the size of the data. */
	for (i = 0; dhcp_options[code].format[i]; i++) {
		if (!numhunk) {
			warning("%s: Excess information in format string: %s",
			    dhcp_options[code].name,
			    &(dhcp_options[code].format[i]));
			break;
		}
		numelem++;
		fmtbuf[i] = dhcp_options[code].format[i];
		switch (dhcp_options[code].format[i]) {
		case 'A':
			--numelem;
			fmtbuf[i] = 0;
			numhunk = 0;
			break;
		case 'X':
			for (k = 0; k < len; k++)
				if (!isascii(data[k]) ||
				    !isprint(data[k]))
					break;
			if (k == len) {
				fmtbuf[i] = 't';
				numhunk = -2;
			} else {
				fmtbuf[i] = 'x';
				hunksize++;
				comma = ':';
				numhunk = 0;
			}
			fmtbuf[i + 1] = 0;
			break;
		case 't':
			fmtbuf[i] = 't';
			fmtbuf[i + 1] = 0;
			numhunk = -2;
			break;
		case 'I':
		case 'l':
		case 'L':
			hunksize += 4;
			break;
		case 's':
		case 'S':
			hunksize += 2;
			break;
		case 'b':
		case 'B':
		case 'f':
			hunksize++;
			break;
		case 'e':
			break;
		default:
			warning("%s: garbage in format string: %s",
			    dhcp_options[code].name,
			    &(dhcp_options[code].format[i]));
			break;
		}
	}

	/* Check for too few bytes... */
	if (hunksize > len) {
		warning("%s: expecting at least %d bytes; got %d",
		    dhcp_options[code].name, hunksize, len);
		return ("<error>");
	}
	/* Check for too many bytes... */
	if (numhunk == -1 && hunksize < len)
		warning("%s: %d extra bytes",
		    dhcp_options[code].name, len - hunksize);

	/* If this is an array, compute its size. */
	if (!numhunk)
		numhunk = len / hunksize;
	/* See if we got an exact number of hunks. */
	if (numhunk > 0 && numhunk * hunksize < len)
		warning("%s: %d extra bytes at end of array",
		    dhcp_options[code].name, len - numhunk * hunksize);

	/* A one-hunk array prints the same as a single hunk. */
	if (numhunk < 0)
		numhunk = 1;

	/* Cycle through the array (or hunk) printing the data. */
	for (i = 0; i < numhunk; i++) {
		for (j = 0; j < numelem; j++) {
			int opcount;
			switch (fmtbuf[j]) {
			case 't':
				if (emit_quotes) {
					*op++ = '"';
					opleft--;
				}
				for (; dp < data + len; dp++) {
					if (!isascii(*dp) ||
					    !isprint(*dp)) {
						if (dp + 1 != data + len ||
						    *dp != 0) {
							_snprintf(op, opleft,
							    "\\%03o", *dp);
							op += 4;
							opleft -= 4;
						}
					} else if (*dp == '"' ||
					    *dp == '\'' ||
					    *dp == '$' ||
					    *dp == '`' ||
					    *dp == '\\') {
						*op++ = '\\';
						*op++ = *dp;
						opleft -= 2;
					} else {
						*op++ = *dp;
						opleft--;
					}
				}
				if (emit_quotes) {
					*op++ = '"';
					opleft--;
				}

				*op = 0;
				break;
			case 'I':
				foo.s_addr = htonl(getULong(dp));
				strncpy(op, inet_ntoa(foo), opleft - 1);
				op[opleft - 1] = ANSI_NULL;
				opcount = strlen(op);
				if (opcount >= opleft)
					goto toobig;
				opleft -= opcount;
				dp += 4;
				break;
			case 'l':
				opcount = _snprintf(op, opleft, "%ld",
				    (long)getLong(dp));
				if (opcount >= opleft || opcount == -1)
					goto toobig;
				opleft -= opcount;
				dp += 4;
				break;
			case 'L':
				opcount = _snprintf(op, opleft, "%ld",
				    (unsigned long)getULong(dp));
				if (opcount >= opleft || opcount == -1)
					goto toobig;
				opleft -= opcount;
				dp += 4;
				break;
			case 's':
				opcount = _snprintf(op, opleft, "%d",
				    getShort(dp));
				if (opcount >= opleft || opcount == -1)
					goto toobig;
				opleft -= opcount;
				dp += 2;
				break;
			case 'S':
				opcount = _snprintf(op, opleft, "%d",
				    getUShort(dp));
				if (opcount >= opleft || opcount == -1)
					goto toobig;
				opleft -= opcount;
				dp += 2;
				break;
			case 'b':
				opcount = _snprintf(op, opleft, "%d",
				    *(char *)dp++);
				if (opcount >= opleft || opcount == -1)
					goto toobig;
				opleft -= opcount;
				break;
			case 'B':
				opcount = _snprintf(op, opleft, "%d", *dp++);
				if (opcount >= opleft || opcount == -1)
					goto toobig;
				opleft -= opcount;
				break;
			case 'x':
				opcount = _snprintf(op, opleft, "%x", *dp++);
				if (opcount >= opleft || opcount == -1)
					goto toobig;
				opleft -= opcount;
				break;
			case 'f':
				opcount = (size_t) strncpy(op, *dp++ ? "true" : "false", opleft - 1);
				op[opleft - 1] = ANSI_NULL;
				if (opcount >= opleft)
					goto toobig;
				opleft -= opcount;
				break;
			default:
				warning("Unexpected format code %c", fmtbuf[j]);
			}
			op += strlen(op);
			opleft -= strlen(op);
			if (opleft < 1)
				goto toobig;
			if (j + 1 < numelem && comma != ':') {
				*op++ = ' ';
				opleft--;
			}
		}
		if (i + 1 < numhunk) {
			*op++ = comma;
			opleft--;
		}
		if (opleft < 1)
			goto toobig;

	}
	return (optbuf);
 toobig:
	warning("dhcp option too large");
	return ("<error>");
}

void
do_packet(struct interface_info *interface, struct dhcp_packet *packet,
    int len, unsigned int from_port, struct iaddr from, struct hardware *hfrom)
{
	struct packet tp;
	int i;

	if (packet->hlen > sizeof(packet->chaddr)) {
		note("Discarding packet with invalid hlen.");
		return;
	}

	memset(&tp, 0, sizeof(tp));
	tp.raw = packet;
	tp.packet_length = len;
	tp.client_port = from_port;
	tp.client_addr = from;
	tp.interface = interface;
	tp.haddr = hfrom;

	parse_options(&tp);
	if (tp.options_valid &&
	    tp.options[DHO_DHCP_MESSAGE_TYPE].data)
		tp.packet_type = tp.options[DHO_DHCP_MESSAGE_TYPE].data[0];
	if (tp.packet_type)
		dhcp(&tp);
	else
		bootp(&tp);

	/* Free the data associated with the options. */
	for (i = 0; i < 256; i++)
		if (tp.options[i].len && tp.options[i].data)
			free(tp.options[i].data);
}