/**
 * Checks if a request comes from a trusted domain.
 * If not calls function to respond with 403 to REGISTER or clean the message of
 * untrusted headers
 * @param msg - the SIP message
 * @param str1 - not used
 * @param str2 - not used
 * @returns #CSCF_RETURN_TRUE if trusted, #CSCF_RETURN_FALSE if not , #CSCF_RETURN_ERROR on REGISTER or error 
 */
int I_NDS_check_trusted(struct sip_msg* msg, char* str1, char* str2)
{
	int result;
	LM_DBG("DBG:I_NDS_check_trusted: Starting ...\n");
	if (msg->first_line.type!=SIP_REQUEST) {
		LM_ERR("ERR:I_NDS_check_trusted: The message is not a request\n");
		result = CSCF_RETURN_TRUE;	
		goto done;
	}
	if (I_NDS_is_trusted(msg,str1,str2)){
		LM_DBG("INF:I_NDS_check_trusted: Message comes from a trusted domain\n");
		result = CSCF_RETURN_TRUE;	
		goto done;
	} else {
		LM_DBG("INF:I_NDS_check_trusted: Message comes from an untrusted domain\n");
		result = CSCF_RETURN_FALSE;					
		if (msg->first_line.u.request.method.len==8 &&
			memcmp(msg->first_line.u.request.method.s,"REGISTER",8)==0){
			slb.sreply(msg,403,&str_msg_403);
			LM_DBG("INF:I_NDS_check_trusted: REGISTER request terminated.\n");
		} else {
			if (!I_NDS_strip_headers(msg,str1,str2)){
				result = CSCF_RETURN_ERROR;
				slb.sreply(msg,500,&str_msg_500);
				LM_DBG("INF:I_NDS_check_trusted: Stripping untrusted headers failed, Responding with 500.\n");				
			}
		}					
	}
	
done:	
	LM_DBG("DBG:I_NDS_check_trusted: ... Done\n");
	return result;
}

static int auth_send_reply(struct sip_msg *msg, int code, char *reason,
					char *hdr, int hdr_len)
{
        str reason_str;

	/* Add new headers if there are any */
	if ((hdr!=NULL) && (hdr_len>0)) {
		if (add_lump_rpl(msg, hdr, hdr_len, LUMP_RPL_HDR)==0) {
			LM_ERR("failed to append hdr to reply\n");
			return -1;
		}
	}

	reason_str.s = reason;
	reason_str.len = strlen(reason);

	return force_stateless_reply ?
	    slb.sreply(msg, code, &reason_str) :
	    slb.freply(msg, code, &reason_str);
}

static int xcaps_send_reply(sip_msg_t *msg, int code, str *reason,
		str *hdrs, str *ctype, str *body)
{
	str tbuf;

	if(hdrs && hdrs->len>0)
	{
		if (add_lump_rpl(msg, hdrs->s, hdrs->len, LUMP_RPL_HDR) == 0)
		{
			LM_ERR("failed to insert extra-headers lump\n");
			return -1;
		}
	}

	if(ctype && ctype->len>0)
	{
		/* add content-type */
		tbuf.len=sizeof("Content-Type: ") - 1 + ctype->len + CRLF_LEN;
		tbuf.s=pkg_malloc(sizeof(char)*(tbuf.len));

		if (tbuf.len==0)
		{
			LM_ERR("out of pkg memory\n");
			return -1;
		}
		memcpy(tbuf.s, "Content-Type: ", sizeof("Content-Type: ") - 1);
		memcpy(tbuf.s+sizeof("Content-Type: ") - 1, ctype->s, ctype->len);
		memcpy(tbuf.s+sizeof("Content-Type: ") - 1 + ctype->len,
				CRLF, CRLF_LEN);
		if (add_lump_rpl(msg, tbuf.s, tbuf.len, LUMP_RPL_HDR) == 0)
		{
			LM_ERR("failed to insert content-type lump\n");
			pkg_free(tbuf.s);
			return -1;
		}
		pkg_free(tbuf.s);
	}
	if(body && body->len>0)
	{
		if (add_lump_rpl(msg, body->s, body->len, LUMP_RPL_BODY) < 0)
		{
			LM_ERR("Error while adding reply lump\n");
			return -1;
		}
	}
	if (slb.freply(msg, code, reason) < 0)
	{
		LM_ERR("Error while sending reply\n");
		return -1;
	}
	return 0;
}

/**
 * Send a reply (response) to the passed in SIP request messsage with
 * the code and reason. If the header is not NULL (and header_len !=
 * 0) the add the header to the reply message.
 *
 * @param request The SIP request message to build the reply from.
 * @param code The response code. i.e 200
 * @param reason The response reason. i.e. "OK"
 * @param header the header block to add to the reply.
 * @param header_len The length of the header block. (header)
 *
 * @return 0 on success, none-zero on an error.
 */
static int send_response(struct sip_msg *request, int code, str *reason,
		char *header, int header_len) 
{

	if (slb.freply != 0) {
		/* Add new headers if not null or zero length */
		if ((header) && (header_len)) {
			if (add_lump_rpl(request, header, header_len, LUMP_RPL_HDR) == 0) {
				/* An error with adding the lump */
				LM_ERR("unable to append header.\n");
				return -1;
			}
		}
		/* Now using the sl function, send the reply/response */
		if (slb.freply(request, code, reason) < 0) {
			LM_ERR("Unable to sent reply.\n");
			return -1;
		}
	}
	else {
		return -1;
	}
	return(0);
}

/*! \brief Initialize siptrace module */
static int mod_init(void)
{
	pv_spec_t avp_spec;
	sl_cbelem_t slcb;

#ifdef STATISTICS
	/* register statistics */
	if (register_module_stats(exports.name, siptrace_stats)!=0)
	{
		LM_ERR("failed to register core statistics\n");
		return -1;
	}
#endif

	if(register_mi_mod(exports.name, mi_cmds)!=0)
	{
		LM_ERR("failed to register MI commands\n");
		return -1;
	}
	if(siptrace_init_rpc() != 0) 
	{
		LM_ERR("failed to register RPC commands\n");
		return -1;
	}

	if (trace_flag<0 || trace_flag>(int)MAX_FLAG)
	{
		LM_ERR("invalid trace flag %d\n", trace_flag);
		return -1;
	}
	trace_flag = 1<<trace_flag;

	trace_to_database_flag = (int*)shm_malloc(sizeof(int));
	if(trace_to_database_flag==NULL) {
		LM_ERR("no more shm memory left\n");
		return -1;
	}

	*trace_to_database_flag = trace_to_database;

	if(hep_version != 1 && hep_version != 2) {
		LM_ERR("unsupported version of HEP");
		return -1;
	}

	/* Find a database module if needed */
	if(trace_to_database_flag!=NULL && *trace_to_database_flag!=0) {
		if (db_bind_mod(&db_url, &db_funcs))
		{
			LM_ERR("unable to bind database module\n");
			return -1;
		}
		if (trace_to_database_flag && !DB_CAPABILITY(db_funcs, DB_CAP_INSERT))
		{
			LM_ERR("database modules does not provide all functions needed"
					" by module\n");
			return -1;
		}
	}

	if(hep_version != 1 && hep_version != 2) {

		LM_ERR("unsupported version of HEP");
		return -1;
	}

	trace_on_flag = (int*)shm_malloc(sizeof(int));
	if(trace_on_flag==NULL) {
		LM_ERR("no more shm memory left\n");
		return -1;
	}

	*trace_on_flag = trace_on;

	xheaders_write_flag = (int*)shm_malloc(sizeof(int));
	xheaders_read_flag = (int*)shm_malloc(sizeof(int));
	if (!(xheaders_write_flag && xheaders_read_flag)) {
		LM_ERR("no more shm memory left\n");
		return -1;
	}
	*xheaders_write_flag = xheaders_write;
	*xheaders_read_flag = xheaders_read;

	/* register callbacks to TM */
	if (load_tm_api(&tmb)!=0) {
		LM_WARN("can't load tm api. Will not install tm callbacks.\n");
	} else if(tmb.register_tmcb( 0, 0, TMCB_REQUEST_IN, trace_onreq_in, 0, 0) <=0) {
		LM_ERR("can't register trace_onreq_in\n");
		return -1;
	}

	/* bind the SL API */
	if (sl_load_api(&slb)!=0) {
		LM_WARN("cannot bind to SL API. Will not install sl callbacks.\n");
	} else {
		/* register sl callbacks */
		memset(&slcb, 0, sizeof(sl_cbelem_t));

		slcb.type = SLCB_REPLY_READY;
//.........这里部分代码省略.........

static int opt_reply(struct sip_msg* _msg, char* _foo, char* _bar) 
{
	str rpl_hf;
	int offset = 0;

	if ((_msg->REQ_METHOD != METHOD_OTHER) ||
	    (_msg->first_line.u.request.method.len != OPTIONS_LEN) ||
	    (strncasecmp(_msg->first_line.u.request.method.s, OPTIONS, OPTIONS_LEN) != 0)) {
		LOG(L_ERR, "options_reply(): called for non-OPTIONS request\n");
		return -1;
	}

	/* FIXME: should we additionally check if ruri == server addresses ?! */
	/* janakj: no, do it in the script */
	if (_msg->parsed_uri.user.len != 0) {
		LOG(L_ERR, "options_reply(): ruri contains username\n");
		return -1;
	}

	/* calculate the length and allocated the mem */
	rpl_hf.len = ACPT_STR_LEN + ACPT_ENC_STR_LEN + ACPT_LAN_STR_LEN +
			SUPT_STR_LEN + 4 * CRLF_LEN + acpt_body.len + acpt_enc_body.len +
			acpt_lan_body.len + supt_body.len;
	rpl_hf.s = (char*)pkg_malloc(rpl_hf.len);
	if (!rpl_hf.s) {
		LOG(L_CRIT, "options_reply(): out of memory\n");
		goto error;
	}

	/* create the header fields */
	memcpy(rpl_hf.s, ACPT_STR, ACPT_STR_LEN);
	offset = ACPT_STR_LEN;
	memcpy(rpl_hf.s + offset, acpt_body.s, acpt_body.len);
	offset += acpt_body.len;
	memcpy(rpl_hf.s + offset, CRLF, CRLF_LEN);
	offset += CRLF_LEN;

	memcpy(rpl_hf.s + offset, ACPT_ENC_STR, ACPT_ENC_STR_LEN);
	offset += ACPT_ENC_STR_LEN;
	memcpy(rpl_hf.s + offset, acpt_enc_body.s, acpt_enc_body.len);
	offset += acpt_enc_body.len;
	memcpy(rpl_hf.s + offset, CRLF, CRLF_LEN);
	offset += CRLF_LEN;

	memcpy(rpl_hf.s + offset, ACPT_LAN_STR, ACPT_LAN_STR_LEN);
	offset += ACPT_LAN_STR_LEN;
	memcpy(rpl_hf.s + offset, acpt_lan_body.s, acpt_lan_body.len);
	offset += acpt_lan_body.len;
	memcpy(rpl_hf.s + offset, CRLF, CRLF_LEN);
	offset += CRLF_LEN;

	memcpy(rpl_hf.s + offset, SUPT_STR, SUPT_STR_LEN);
	offset += SUPT_STR_LEN;
	memcpy(rpl_hf.s + offset, supt_body.s, supt_body.len);
	offset += supt_body.len;
	memcpy(rpl_hf.s + offset, CRLF, CRLF_LEN);
	offset += CRLF_LEN;

#ifdef EXTRA_DEBUG
	if (offset != rpl_hf.len) {
		LOG(L_CRIT, "options_reply(): headerlength (%i) != offset (%i)\n",
			rpl_hf.len, offset);
		abort();
	}
#endif

	if (add_lump_rpl( _msg, rpl_hf.s, rpl_hf.len,
	LUMP_RPL_HDR|LUMP_RPL_NODUP)!=0) {
		if (sl.reply(_msg, 200, "OK") == -1) {
			LOG(L_ERR, "options_reply(): failed to send 200 via send_reply\n");
			return -1;
		} else {
			return 0;
		}
	} else {
		pkg_free(rpl_hf.s);
		LOG(L_ERR, "options_reply(): add_lump_rpl failed\n");
	}

error:
	if (sl.reply(_msg, 500, "Server internal error") == -1) {
		LOG(L_ERR, "options_reply(): failed to send 500 via send_reply\n");
		return -1;
	} else {
		return 0;
	}
}