int recv_sb_msdp(struct session *ses, int cplen, unsigned char *src)
{
	char buf[BUFFER_SIZE], var[BUFFER_SIZE], val[BUFFER_SIZE];
	char *pto;
	int i, nest, state;

	var[0] = val[0] = i = nest = state = 0;

	if (skip_sb(ses, cplen, src) > cplen)
	{
		return cplen + 1;
	}

	while (i < cplen && src[i] != SE)
	{
		switch (src[i])
		{
			case MSDP_VAR:
				i++;
				pto = buf;

				while (i < cplen && src[i] > 4 && src[i] != IAC)
				{
					*pto++ = src[i++];
				}
				*pto = 0;

				substitute(ses, buf, var, SUB_SEC);

				state = MSDP_STATE_NEW;
				break;

			case MSDP_VAL:
				pto = val;

				while (i < cplen)
				{
					switch (src[i])
					{
						case MSDP_VAR:
							if (nest == 0)
							{
								goto end_val;
							}

							if (state == MSDP_STATE_VAL)
							{
								*pto++ = '}';
							}
							*pto++ = '{';

							state = MSDP_STATE_VAR;
							break;

						case MSDP_VAL:
							if (state == MSDP_STATE_VAR)
							{
								*pto++ = '}';
								*pto++ = '{';
								state = MSDP_STATE_VAL;
							}
							else if (state == MSDP_STATE_VAL)
							{
								*pto++ = COMMAND_SEPARATOR;
							}
							else
							{
								state = MSDP_STATE_VAL;
							}
							break;

						case MSDP_OPEN:
							if (++nest > 1)
							{
								*pto++ = '{';
							}
							state = MSDP_STATE_NEW;
							break;

						case MSDP_CLOSE:
							if (--nest > 0)
							{
								*pto++ = '}';
							}
							if (state == MSDP_STATE_VAL)
							{
								*pto++ = '}';
							}
							state = MSDP_STATE_NEW;
							break;

						case IAC:
							goto end_val;

						case '\\':
							*pto++ = '\\';
							*pto++ = '\\';
							break;

						case '{':
							*pto++ = '\\';
							*pto++ = 'x';
							*pto++ = '7';
							*pto++ = 'B';
							break;

						case '}':
							*pto++ = '\\';
							*pto++ = 'x';
							*pto++ = '7';
							*pto++ = 'D';
							break;

						case COMMAND_SEPARATOR:
							*pto++ = '\\';
							*pto++ = COMMAND_SEPARATOR;
							break;
							
						default:
							*pto++ = src[i];
							break;
					}
					i++;
				}

				end_val:

				*pto = 0;

				telopt_debug(ses, "IAC SB MSDP VAR (%s) %*s VAL (%s)", var, 20 - strlen(var), "", val);

				check_all_events(ses, 0, 2, "IAC SB MSDP", var, val);
				break;

			default:
				i++;
				break;
		}
	}

	telopt_debug(ses, "IAC SB MSDP IAC SE");

	check_all_events(ses, 0, 0, "IAC SB MSDP IAC SE");
	return UMIN(i + 1, cplen);
}