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1. Data Type s Macro Name Macro Description for Macro Parms IFS PPP SPEED Set serial PPP speed bps longword IFS PPP RTSPIN Define the RTS pin int char int IFS PPP CTSPIN Define the CTS pin int int 2 Use parallel port D instead of parallel port C for IFS _PPP_USEPORTD i bool Doaa serial ports A and B IFS_PPP_FLOWCONTROL Turn hardware flow control on or off bool gt An optional string to send to the modem after IFS_PPP_HANGUP char PPP shuts down When enabled sends modem escape sequences before send expect or hangup sequence is IFS_PPP_MODEMESCAPE lt delay gt lt delay gt This is recognized by bool almost all modems to force them into command mode A formatted send and expect sequence for IFS PPP SENDEXPECT Pee char eg dialing and shell login IFS PPP _USEMODEM Specify whether to use modem dialout string bool All of these IFS PPP _ macros have IFG_PPP_ versions that allow an application to look at the properties that have been set The parameter for the IFS PPP SENDEXPECT option is a string containing a send expect script to run when the PPP connection comes up It is a series of tokens separated by spaces alternating between a string to transmit and a string to expect back PPP Driver Module 020 0062 Rev A 7 For example SEscript ATDT5551212 CONNECT ogin Joe User word secret PPP The sequence is 1 Send ATDT5551212 dials up an ISP 2 Wait for the2. LIBRARY PPP LIB PPPshutdown int PPPshutdown unsigned long timeout DESCRIPTION Sends a Link Terminate Request packet Waits for link to be torn down PARAMETERS timeout Number of milliseconds to wait before giving up on a response from the peer RETURN VALUE 1 Shutdown succeeded 0 Shutdown timed out LIBRARY PPP LIB PPP Driver Module 020 0062 Rev A 16
3. LCP If this is not appropriate do not use IFS PPP _SENDEXPECT or IFS_PPP_USEMODEM Instead use the facilities of MODEM LIB to perform an appropriate login to the ISP Only when this is complete should you call ifup Use of MODEM LIB entails some limitations e Only one PPP serial interface can use MODEM LIB e You need to configure MODEM LIB to match the serial port you are using for PPP e Ensure that you specify an IFCONFIG PPP default such that the interface remains down at boot time In other words do not append IFS_UP to the IFCONFIG_PPP definition PPP Driver Module 020 0062 Rev A 8 5 5 Starting and Stopping PPP Interfaces The details of establishing and tearing down PPP links are handled by sock init and tcp tick as are all other TCP IP functions To start a PPP interface ifup is used just as it is for non PPPoE Ethernet interfaces One dif ference that you should note is that the interface will not usually be up after ifup returns ifup only sets the process in motion which takes much longer for PPP than it does for non PPPoE Ethernet Your application should be aware of this since you will not be able to open sockets on an interface that is not fully enabled If necessary you can poll the interface to wait for it to come up While polling you must call tcp_tick regularly This is because it is actually the processing driven from tcp tick that drives the whole PPP negotiation machine
4. PPP properties set during initialization are Table 4 Macros for PPP Initialization Serial and Ethernet Bare Data Type s for Macro Name Macro Description Macro Parma IFS PPP ACCEPTIP Accept peer s idea of our local IP address bool IFS PPP REMOTEIP Try to set IP address of peer longword IFS PPP ACCEPTDNS Accept a DNS server IP address from peer bool a Set DNS server IP addresses for peer longword IFS PPP REMOTEDNS primary and secondary longword Called when a peer attempts to f IFS PPP AUTHCALLBACK P P int 0 Ste authenticate IFS PPP INIT Sets up PPP with default parameters none Sets username and password to give to IFS PPP REMOTEAUTH P g char char peer Required username and password for IFS PPP LOCALAUTH incoming peer char char All of these IFS _PPP_ macros except the initialization and callback have IFG_PPP_ ver sions that allow an application to look at the properties that have been set PPP Driver Module 020 0062 Rev A 5 4 ifconfig Options for Serial PPP The ifconfig parameter identifiers described in this section pertain to serial PPP interfaces only You can specify these options for PPPoE interfaces but they will be quietly ignored They may also be used in the appropriate IFCONFIG PPP macro definitions for boot time initializa tion Table 5 Macros for PPP Initialization for Serial
5. receiving characters over the serial link It also handles the insertion and detection of escape characters and CRC generation and checking PPPOE LIB Contains handlers for the PPPoE physical layer which is mainly the access concentra tor discovery mechanism and the addition of the PPPoE header to Ethernet packets This library calls the Ethernet driver library to handle the Ethernet physical layer PPP Driver Module 020 0062 Rev A 1 A fourth library MODEM LIB contains functions for controlling an external modem through a full RS232 link MODEM LIB should not be required for most ISP connections since most ISPs these days auto detect the use of PPP and do not require any special logon screen navigation Basic dial up to an ISP is handled directly by if config settings which do not require any special modem control providing that your modem has a Hayes compatible interface MODEM LIB is not directly related to PPP It allows ASCII strings to be sent to and received from the modem Typically these strings are AT commands and modem responses If you have special requirements for establishing communications with an ISP that cannot be han dled by the default PPP library methods you will need to explicitly include MODEM LIB and write a program to establish the communications link The program will typically need to com mand the modem to dial out wait for a valid connection send a user ID and password to the ISP and validate th
6. Dynamic C Module RABE Aor PPP Driver The PPP packet driver is a set of libraries in Dynamic C that allows the user to establish a PPP Point to Point Protocol link over a full duplex serial line between a Rabbit based controller and another system that supports PPP You may also establish PPP links over Ethernet PPPoE A common use of the PPP protocol is the transfer of IP packets between a remote host and an Internet Service Provider ISP over a modem connection The PPP packet driver supports the transfer of Internet Protocol IP data and is compatible with all TCP IP libraries for the Rabbit Establishing PPP links has become easier and more flexible You can have as many different PPP interfaces as you have available serial and Ethernet ports You can also run PPP over serial and or Ethernet at the same time as ordinary non PPPoE Ethernet 1 0 PPP Libraries The PPP driver is in three library files PPP LIB Contains routines to handle the link negotiation LCP authentication PAP and IP ne gotiation IPCP These are the three main sub protocols of PPP PPP LIB calls rou tines in the other two libraries to handle the lower level physical layer There are no application callable functions in any of the PPP libraries PPP is mainly controlled via the ifconfig function and friends PPPLINK LIB Contains handlers for the asynchronous serial physical layer namely the interrupt ser vice routine for transmitting and
7. SE_PPP_SERIAL 0x0C which as the bitwise combination of 0x04 and 0x08 specifies SERC IF_PPP2 and SERD IF_PPP3 5 2 PPPoE Port Selection Since all Z World controller boards currently have at most a single Ethernet driver chip only a single PPPoE interface is available however it can be shared with non PPPoE Ethernet over the same hardware non PPPoE Ethernet will use interface IF_ETHO while PPPoE will use IF PPPOEO 5 3 ifconfig Options for PPP The ifconfig parameter identifiers described in this section pertain to any PPP interface whether serial or Ethernet There are a considerable number of options detailed in the Dynamic C TCP IP User s Manual pertinent to PPP over asynchronous serial PPPoE does not as yet require any special configuration options because of its relative simplicity The parameter identifiers listed here are passed to the ifconfig function They can also be used in the appropriate IFCONFIG PPP macro definitions to ensure that the interface s are initialized correctly at boot time For example a run time change to the userid and password might be coded as follows ifconfig IF_PPP2 IFS PPP _REMOTEAUTH myUserid myPassword IFS END PPP Driver Module 020 0062 Rev A 5 The same definition for boot time initialization might be coded as define IFCONFIG PPP2 other parameters IFS PPP REMOTEAUTH myUserid myPassword other parameters The general
8. e response After this has completed successfully PPP can be started using the ifup function For a complete description of ifup and other Dynamic C TCP IP func tions please see the Dynamic C TCP IP User s Manual NOTE MODEM LIB is currently limited to controlling a single modem The modem serial port and control lines are defined using macro constants which should match with the definitions of the PPP interface The sample program Samples PPP modem_test c shows the general idea for using MODEM LIB 2 0 Operation Details for PPP over Serial The first step is to configure whatever transport medium will be used for the PPP connection For directly connecting a serial line to the peer the two serial data lines TX and RX may be adequate The most common situation however will be some sort of modem 2 1 The Modem Interface The interface between a modem and a controller is either a true RS232 interface or a variation on RS232 that uses TTL voltage levels for all of the signals The latter are used by board mounted modem modules If an external modem is used an RS232 transceiver chip is needed to convert RS232 voltages to logic signals and vice versa A full RS232 connection has 3 outputs and 5 inputs from the controller s point of view In RS232 terminology the controller is referred to as the DTE Data Terminal Equipment Modems and other peripherals are referred to as DCE s Data Communications Equipment The specifics o
9. ecause the hardware Ethernet is easy to set up and no modems are involved Actually you might have something called a DSL modem or similar but this type of modem does not have to do dial up in the usual sense PPPoE is selected by defining the symbol USE_ PPPOE to be a non zero value Currently the only value supported is 1 with 2 reserved for future controller boards that have a second Ethernet chip If you define USE PPPOE then you should also define IFCONFIG PPPOEO to contain initialization options passed to ifconfig When PPPoE is specified the interface is referred to by IF_PPPOEO IF_PPPOE1 is reserved for future boards PPP Driver Module 020 0062 Rev A 3 4 0 Link Control Protocol Options Link Control Protocol is the first sub protocol used on a PPP link The following LCP options are supported by the Rabbit PPP system Table 2 Configuration Options Geena SE ed Meaning of Option Type 01 MRU Maximum Receive Unit 02 ACCM Async Control Character Map 03 Auth Authentication Type PAP only 05 Magic Number 07 PFC Protocol Field Compression 08 ACFC Address and Control Field Compression For more information on these options refer to RFC 1661 The Point to Point Protocol PPP at http www faqs org rfcs rfcl661 html 5 0 Configuring PPP Since multiple interfaces are supported your application should call if config to change PPP interface parameters at
10. f a dial up PPP connection are dependent on the modem hardware and the ISP PPP Driver Module 020 0062 Rev A 2 2 1 1 Rabbit Pin Connections to Modem The modem control library MODEM LIB defines default connections to the Rabbit as follows Table 1 Rabbit Pin Assignments for Modem Connection RS232 Signal Rabbit Pin Direction DTR PB6 out RTS PB7 out CTS PBO in DCD PB2 in RI PB3 in DSR PB4 in TD PC2 out RD PC3 in 2 2 Flow Control Hardware flow control is implemented for the Rabbit PPP system It follows the RS232 conven tion of using Ready To Send RTS and Clear To Send CTS lines Flow control is not required for speeds up to and including 115200 bps The internal character pro cessing is fast enough that the controller does not have to throttle incoming data flow However the modem or peer may need to throttle transmitted data It is recommended that the RTS modem to controller line be connected for modems that cannot handle a continuous data stream at the specified rate You can also connect the CTS controller to modem line but the controller will merely assert this line continuously To enable or disable hardware flow control call ifconfig withthe IFS PPP FLOWCONTROL parameter identifier You should also specify IFS PPP _RTSPIN and IFS PPP CTSPIN parameter identifiers 3 0 Operation Details for PPPoE PPPoE avoids most of the complexities of PPP over serial This is b
11. ine is asserted RETURN VALUE 1 DSR line is active 0 DSR inactive nothing connected LIBRARY MODEM LIB ModemRinging int ModemRinging void DESCRIPTION Returns true if the RI line is asserted meaning that the line is ringing RETURN VALUE 1 RI line is active 0 RI inactive nothing connected LIBRARY MODEM LIB ModemSend void ModemSend char send string DESCRIPTION Sends a string to the modem PARAMETERS send string A NULL terminated string to be sent to the modem LIBRARY MODEM LIB PPP Driver Module 020 0062 Rev A 13 ModemStartPPP void ModemStartPPP void DESCRIPTION Hands control of the serial line over to the PPP driver LIBRARY MODEM LIB PPPactive int PPPactive void DESCRIPTION Returns boolean value indicating if there is currently an active link to a peer RETURN VALUE gt 0 Active link to peer 0 No active link LIBRARY PPP LIB PPPnegotiateIP void PPPnegotiateIP unsigned long local ip unsigned long remote ip DESCRIPTION Sets PPP driver to negotiate IP addresses for itself and the remote peer Otherwise the system will rely on the remote peer to set addresses PARAMETERS local _ip IP number to use for this PPP connection remote ip IP number that the remote peer should be set to LIBRARY PPP LIB PPP Driver Module 020 0062 Rev A 14 PPPSerialGetErrors word PPPSerialGetErrors void DESCRIPTION Gets a bi
12. run time or define suitable IFCONFIG_PPP macros for boot time con figuration of each PPP interface both serial and PPPoE You select serial port hardware to use with PPP by defining USE PPP SERIAL before including dertcp 1lib Similarly you select PPPoE by defining USE PPPOE 5 1 Serial Port Selection PPP over asynchronous serial requires a suitable Rabbit serial port to be selected You can use any of the available ports since they all support asynchronous communications The serial port selection is entirely dynamic however there is a fixed mapping between interface numbers and serial port hardware IF_PPPO always represents serial port A IF_PPP1 is always serial port B and so on PPP Driver Module 020 0062 Rev A 4 The serial port hardware to use is determined by the USE PPP SERIAL macro which your application defines in order to specify PPP serial interfaces USE PPP SERIAL is set to a bit wise OR combination of numbers representing the desired serial port s Ports are assigned according to the following table Table 3 Bitmap Values for USE_PPP SERIAL Interface Number Serial Port Bitmap Value IF_PPPO SERA 0x01 IF_PPP1 SERB 0x02 IF_PPP2 SERC 0x04 IF_PPP3 SERD 0x08 The Rabbit 3000 supports an additional two serial ports SERE and SERF however the TCP IP library does not fully support use of these ports for PPP If multiple PPP serial interfaces are required use for example define U
13. ry The correct way to poll an interface is given by the following code fragment This code includes tests for the possibility that the interface may not be able to come up e g because of a time out ifup IF_PPP2 while ifpending IF PPP2 1 tcp tick if ifstatus IF_PPP2 printf Failed n A similar consideration applies for bringing the interface down ifidown IF_PPP2 while ifpending IF PPP2 3 tcp tick Note that there is no need to test for an interface failing to come down however the tear down process may take a short time If you wait for the interface to come down before restarting it then there is a better chance that the link will come back up successfully since the peer will have been notified properly NOTE For PPP links with IFS PPP USEMODEM in effect the process of bringing the interface up and down will include the modem dial out and hang up procedure If you had USEMODEM in effect when connecting but turned it off during the connection then ifdown will not perform modem hang up You will need to manually hang up the modem or possibly just renegotiate from the LCP phase if this is what you intended by calling ifup PPP Driver Module 020 0062 Rev A 9 6 0 API Functions This section describes the functions for modem control ModemClose void ModemClose void DESCRIPTION Closes the serial driver down LIBRARY MODEM LIB ModemConnected in
14. t ModemConnected void DESCRIPTION Returns true if the DCD line is asserted meaning the modem is connected to a remote carrier RETURN VALUE 1 DCD line is active 0 DCD inactive nothing connected LIBRARY MODEM LIB PPP Driver Module 020 0062 Rev A 10 ModemExpect int ModemExpect char send string unsigned long timeout DESCRIPTION Listens for a specific string to be sent by the modem PARAMETERS send string A NULL terminated string to listen for timeout Maximum wait in milliseconds for a character RETURN VALUE 1 The expected string was received 0 A timeout occurred before receiving the string LIBRARY MODEM LIB ModemHangup int ModemHangup void DESCRIPTION Sends ATH and ATZ commands RETURN VALUE 1 Success 0 Modem not responding LIBRARY MODEM LIB PPP Driver Module 020 0062 Rev A 11 ModemInit int ModemInit void DESCRIPTION Resets modem with AT ATZ commands RETURN VALUE 1 Success 0 Modem not responding LIBRARY MODEM LIB ModemOpen int ModemOpen unsigned long baud DESCRIPTION Starts up communication with an external modem PARAMETERS baud The baud rate for communicating with the modem RETURN VALUE 1 External modem detected 0 Not connected to external modem LIBRARY MODEM LIB PPP Driver Module 020 0062 Rev A 12 ModemReady int ModemReady void DESCRIPTION Returns true if the DSR l
15. t field with flags set for any errors that occurred These flags are then cleared so that a particular error will only cause the flag to be set once RETURN VALUE A bit field with flags for various errors The errors along with their bit masks are as fol lows PPP NOBUFFER 0x01 PPP RXOVERRUN 0x02 PPP BUFFEROVERFLOW 0x08 The high byte of the return value contains the number of CRC errors since the last call to this function 0 255 LIBRARY PPPLINK LIB PPPsetAuthenticatee void PPPsetAuthenticatee char username char password DESCRIPTION Sets the driver up to send a PAP authentication message to a peer when requested PARAMETERS username The username to send to the peer The argument string is not cop ied so the argument string must stay constant password The password to send to the peer The argument string is not cop ied so the argument string must stay constant LIBRARY PPP LIB PPP Driver Module 020 0062 Rev A 15 PPPsetAuthenticator void PPPsetAuthenticator char username char password DESCRIPTION Sets the driver up to require a PAP authentication message from a peer Negotiation will fail unless the peer sends the specified username password pair This function is gener ally used when the Rabbit is acting as a dial in server PARAMETERS username The user name that the peer must match for the link to proceed password The password that the peer must match for the link to proceed
16. word CONNECT 3 An empty send string means don t send anything and wait for the next expect string 4 Wait for login or Login By leaving off the L either one will match 5 Send Joe User Note that this token is contained in single quotes because it contains a space within it 6 Wait for password or Password 7 Send the password 8 Wait for the sequence PPP This indicates a PPP session has started 5 4 1 Additional Rules for Send Expect Scripts e A carriage return character ASCII 13 is automatically sent after each send token e An ampersand amp at the start of an expect token indicates that the driver should wait indef initely for that token to be received This is useful when waiting to answer a call e g To set the modem to answer and wait indefinitely for a connection ATSO 1 amp CONNECT e As mentioned above an empty token is immediately skipped This allows for a chain of expect tokens to be used e The macro PSS MODEM CONNECT WAIT determines the total time for the script If this is exceeded a timeout failure will occur and the interface will fail to come up Using the ampersand modifier resets this timeout Note that the IFS PPP _USEMODEM specifies that PPP assumes that it is talking to a modem When the interface is being brought up it will first run through the send expect script After the script completes PPP will assume that it can launch straight into
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