options.c

DHCP服务器源码

	    /* 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;
		    int consumed = 0;
		    
		    /* 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,
				    od.data + ix, (unsigned)(incr - 1));
			    buffer [bufix + 2 + incr - 1] = 0;
		    } else {
			    memcpy (buffer + bufix + 2,
				    od.data + ix, (unsigned)incr);
		    }
		    length -= incr;
		    ix += incr;
		    bufix += 2 + incr;
	    }
	    data_string_forget (&od, MDL);
	}

	return bufix;
}

/* Format the specified option so that a human can easily read it. */

const char *pretty_print_option (option, data, len, emit_commas, emit_quotes)
	struct option *option;
	const unsigned char *data;
	unsigned len;
	int emit_commas;
	int emit_quotes;
{
	static char optbuf [32768]; /* XXX */
	int hunksize = 0;
	int opthunk = 0;
	int hunkinc = 0;
	int numhunk = -1;
	int numelem = 0;
	char fmtbuf [32];
	struct enumeration *enumbuf [32];
	int i, j, k, l;
	char *op = optbuf;
	const unsigned char *dp = data;
	struct in_addr foo;
	char comma;
	unsigned long tval;

	if (emit_commas)
		comma = ',';
	else
		comma = ' ';
	
	memset (enumbuf, 0, sizeof enumbuf);

	/* Figure out the size of the data. */
	for (l = i = 0; option -> format [i]; i++, l++) {
		if (!numhunk) {
			log_error ("%s: Extra codes in format string: %s",
				   option -> name,
				   &(option -> format [i]));
			break;
		}
		numelem++;
		fmtbuf [l] = option -> format [i];
		switch (option -> format [i]) {
		      case 'a':
			--numelem;
			fmtbuf [l] = 0;
			numhunk = 0;
			break;
		      case 'A':
			--numelem;
			fmtbuf [l] = 0;
			numhunk = 0;
			break;
		      case 'E':
			/* Skip the universe name. */
			while (option -> format [i] &&
			       option -> format [i] != '.')
				i++;
		      case 'X':
			for (k = 0; k < len; k++) {
				if (!isascii (data [k]) ||
				    !isprint (data [k]))
					break;
			}
			/* If we found no bogus characters, or the bogus
			   character we found is a trailing NUL, it's
			   okay to print this option as text. */
			if (k == len || (k + 1 == len && data [k] == 0)) {
				fmtbuf [l] = 't';
				numhunk = -2;
			} else {
				fmtbuf [l] = 'x';
				hunksize++;
				comma = ':';
				numhunk = 0;
			}
			fmtbuf [l + 1] = 0;
			break;
		      case 'd':
		      case 't':
			fmtbuf [l] = 't';
			fmtbuf [l + 1] = 0;
			numhunk = -2;
			break;
		      case 'N':
			k = i;
			while (option -> format [i] &&
			       option -> format [i] != '.')
				i++;
			enumbuf [l] =
				find_enumeration (&option -> format [k] + 1,
						  i - k - 1);
			hunksize += 1;
			hunkinc = 1;
			break;
		      case 'I':
		      case 'l':
		      case 'L':
		      case 'T':
			hunksize += 4;
			hunkinc = 4;
			break;
		      case 's':
		      case 'S':
			hunksize += 2;
			hunkinc = 2;
			break;
		      case 'b':
		      case 'B':
		      case 'f':
			hunksize++;
			hunkinc = 1;
			break;
		      case 'e':
			break;
		      case 'o':
			opthunk += hunkinc;
			break;
		      default:
			log_error ("%s: garbage in format string: %s",
			      option -> name,
			      &(option -> format [i]));
			break;
		} 
	}

	/* Check for too few bytes... */
	if (hunksize - opthunk > len) {
		log_error ("%s: expecting at least %d bytes; got %d",
		      option -> name,
		      hunksize, len);
		return "<error>";
	}
	/* Check for too many bytes... */
	if (numhunk == -1 && hunksize < len)
		log_error ("%s: %d extra bytes",
		      option -> 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)
		log_error ("%s: %d extra bytes at end of array\n",
		      option -> 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++) {
			switch (fmtbuf [j]) {
			      case 't':
				if (emit_quotes)
					*op++ = '"';
				for (; dp < data + len; dp++) {
					if (!isascii (*dp) ||
					    !isprint (*dp)) {
						/* Skip trailing NUL. */
					    if (dp + 1 != data + len ||
						*dp != 0) {
						    sprintf (op, "\\%03o",
							     *dp);
						    op += 4;
					    }
					} else if (*dp == '"' ||
						   *dp == '\'' ||
						   *dp == '$' ||
						   *dp == '`' ||
						   *dp == '\\') {
						*op++ = '\\';
						*op++ = *dp;
					} else
						*op++ = *dp;
				}
				if (emit_quotes)
					*op++ = '"';
				*op = 0;
				break;
				/* pretty-printing an array of enums is
				   going to get ugly. */
			      case 'N':
				if (!enumbuf [j])
					goto enum_as_num;
				for (i = 0; ;i++) {
					if (!enumbuf [j] -> values [i].name)
						goto enum_as_num;
					if (enumbuf [j] -> values [i].value ==
					    *dp)
						break;
				}
				strcpy (op, enumbuf [j] -> values [i].name);
				op += strlen (op);
				break;
			      case 'I':
				foo.s_addr = htonl (getULong (dp));
				strcpy (op, inet_ntoa (foo));
				dp += 4;
				break;
			      case 'l':
				sprintf (op, "%ld", (long)getLong (dp));
				dp += 4;
				break;
			      case 'T':
				tval = getULong (dp);
				if (tval == -1)
					sprintf (op, "%s", "infinite");
				else
					sprintf (op, "%ld", tval);
				break;
			      case 'L':
				sprintf (op, "%ld",
					 (unsigned long)getULong (dp));
				dp += 4;
				break;
			      case 's':
				sprintf (op, "%d", (int)getShort (dp));
				dp += 2;
				break;
			      case 'S':
				sprintf (op, "%d", (unsigned)getUShort (dp));
				dp += 2;
				break;
			      case 'b':
				sprintf (op, "%d", *(const char *)dp++);
				break;
			      case 'B':
			      enum_as_num:
				sprintf (op, "%d", *dp++);
				break;
			      case 'x':
				sprintf (op, "%x", *dp++);
				break;
			      case 'f':
				strcpy (op, *dp++ ? "true" : "false");
				break;
			      default:
				log_error ("Unexpected format code %c",
					   fmtbuf [j]);
			}
			op += strlen (op);
			if (dp == data + len)
				break;
			if (j + 1 < numelem && comma != ':')
				*op++ = ' ';
		}
		if (i + 1 < numhunk) {
			*op++ = comma;
		}
		if (dp == data + len)
			break;
	}
	return optbuf;
}

int get_option (result, universe, packet, lease, client_state,
		in_options, cfg_options, options, scope, code, file, line)
	struct data_string *result;
	struct universe *universe;
	struct packet *packet;
	struct lease *lease;
	struct client_state *client_state;
	struct option_state *in_options;
	struct option_state *cfg_options;
	struct option_state *options;
	struct binding_scope **scope;
	unsigned code;
	const char *file;
	int line;
{
	struct option_cache *oc;

	if (!universe -> lookup_func)
		return 0;
	oc = ((*universe -> lookup_func) (universe, options, code));
	if (!oc)
		return 0;
	if (!evaluate_option_cache (result, packet, lease, client_state,
				    in_options, cfg_options, scope, oc,
				    file, line))
		return 0;
	return 1;
}

void set_option (universe, options, option, op)
	struct universe *universe;
	struct option_state *options;
	struct option_cache *option;
	enum statement_op op;
{
	struct option_cache *oc, *noc;

	switch (op) {
	      case if_statement:
	      case add_statement:
	      case eval_statement:
	      case break_statement:
	      default:
		log_error ("bogus statement type in do_option_set.");
		break;

	      case default_option_statement:
		oc = lookup_option (universe, options,
				    option -> option -> code);
		if (oc)
			break;
		save_option (universe, options, option);
		break;

	      case supersede_option_statement:
	      case send_option_statement:
		/* Install the option, replacing any existing version. */
		save_option (universe, options, option);
		break;

	      case append_option_statement:
	      case prepend_option_statement:
		oc = lookup_option (universe, options,
				    option -> option -> code);
		if (!oc) {
			save_option (universe, options, option);
			break;
		}
		/* If it's not an expression, make it into one. */
		if (!oc -> expression && oc -> data.len) {
			if (!expression_allocate (&oc -> expression, MDL)) {
				log_error ("Can't allocate const expression.");
				break;
			}
			oc -> expression -> op = expr_const_data;
			data_string_copy
				(&oc -> expression -> data.const_data,
				 &oc -> data, MDL);
			data_string_forget (&oc -> data, MDL);
		}
		noc = (struct option_cache *)0;
		if (!option_cache_allocate (&noc, MDL))
			break;
		if (op == append_option_statement) {
			if (!make_concat (&noc -> expression,
					  oc -> expression,
					  option -> expression)) {
				option_cache_dereference (&noc, MDL);
				break;
			}
		} else {
			if (!make_concat (&noc -> expression,
					  option -> expression,
					  oc -> expression)) {
				option_cache_dereference (&noc, MDL);
				break;
			}
		}
		noc -> option = oc -> option;
		save_option (universe, options, noc);
		option_cache_dereference (&noc, MDL);
		break;
	}
}

struct option_cache *lookup_option (universe, options, code)
	struct universe *universe;
	struct option_state *options;
	unsigned code;
{
	if (!options)
		return (struct option_cache *)0;
	if (universe -> lookup_func)
		return (*universe -> lookup_func) (universe, options, code);
	else
		log_error ("can't look up options in %s space.",
			   universe -> name);
	return (struct option_cache *)0;
}

struct option_cache *lookup_hashed_option (universe, options, code)
	struct universe *universe;
	struct option_state *options;
	unsigned code;
{
	int hashix;
	pair bptr;
	pair *hash;

	/* Make sure there's a hash table. */
	if (universe -> index >= options -> universe_count ||
	    !(options -> universes [universe -> index]))