® 12-3 Network Protocols Machines on a network must agree to exchange data in some standard way. Internet protocol suite (also called TCP/IP) provides system independent protocols. VxWorks provides an implementation of TCP/IP protocol suite based on the 4.4BSD release Features include: –Increased configurability and scalability –MUX layer –Support for contemporary Internet features
® 12-4 Network Components
® 12-5 Network Scalability Selective inclusion of core TCP/IP networking protocols is provided. TCP/IP parameters can be set by setting properties of individual components. Examples: TCP Connection Timeout, IP Time-to-Live value, TCP/UDP receive and send buffer sizes, and tuning of internal buffers. (See VxWorks Network Programmers Guide.)
® 12-6 Network Services VxWorks network services include: –DHCP/BOOTP –Simple Network Time Protocol (SNTP) –DNS resolver –Dynamic Routing (RIPv1/RIPv2/OSPF) –rlogin/telnet –Remote command execution –Remote file access –Multicasting, including IGMP User can build other network services as needed.
® 12-8 Host Names To associate a name with an internet address: hostAdd (hostName, hostAddr) To display host name table use: hostShow () The name of the boot host is automatically added to the table from the boot parameters.
® 12-9 Domain Name System Domain Name System (DNS) is a distributed client/server application supporting host names being stored in a distributed database. resolvLib DNS requires a name server and, on the client side, a resolver. VxWorks supports resolver functionality in resolvLib. resolvLib resolvLib includes the following routines: –resolvGetHostByName() -- send a DNS query to the name server for the IP address of a host. –resolvGetHostByAddr() -- send a DNS query to the name server for the host name of an IP address.
® DNS Resolver Configuration ( / network components/networking applications/DNS resolver The DNS resolver component ( / network components/networking applications/DNS resolver ) must be added to VxWorks. The resolver must be initialized before use. Required information includes RESOLVER_DOMAIN and RESOLVER_DOMAIN_SERVER. This can be done through the project facility or by calling resolvInit().
® DHCP Basics Dynamic Host Configuration Protocol (DHCP) allows a host to acquire an IP address, and possibly boot parameters, from a remote host. A DHCP client can obtain a temporary lease of an IP address from a DHCP server, which maintains a database of available addresses and other parameters. A DHCP relay agent is necessary to support DHCP operation across subnet boundaries.
® Routing Overview Internet Protocol (IP) routing algorithm: The target routing table can be built in two ways: –Statically, by adding routes to a local routing table using mRouteAdd() or routeAdd( ). –Or dynamically, where hosts exchange routing information using a routing protocol. VxWorks supports two routing protocols: Routing Information Protocol (RIP) and Open Shortest Path First (OSPF). if (destination on a directly attached network) send data to destination else use routing table to find correct router send data to router
® Adding Static Routes in VxWorks To add multiple routes to the same location, use mRouteAdd (dest, gateway, mask, tos, flags) routeLib Can use a destination/gateway internet address in dot notation. Specify destination subnet mask and IP type-of-service. See routeLib help page for details. To add a route to the /24 network through the router gatehost: mRouteAdd ( , gatehost, 0xffffff00, 0, 0) /network components/networking protocols/network debugging/ Network show routines Routing table show routines, mRouteShow() or routeShow() require the component /network components/networking protocols/network debugging/ Network show routines.
® Network Show Routines Are used to display network statistics and debugging information. Configuration information and statistics can be shown for protocols (IP, ICMP, TCP, etc.), buffering, network interfaces, etc. Example (ARP table entries): - >arptabShow LINK LEVEL ARP TABLE destination gateway flags Refcnt Use Interface :00:20:7b:06:fb ei :60:97:4f:d5: ei value = 75 = 0x4b = K
® Dynamic Routing Overview Dynamic routing protocols allow hosts (typically routers) to exchange routing information. Advantages over statically created routing tables include: –Faster update as link states change –Ability to calculate the most efficient route if there are multiple routes to a destination –Easier maintenance These protocols do not affect the Internet routing algorithm, but instead impose a routing policy when constructing the routing table. VxWorks supports RIP versions 1 and 2 and OSPF (an optional component).
® Routing Internet Protocol RIP uses UDP to exchange routing information. RIP is a distance vector protocol -- each route includes a number of hop counts. If multiple paths to a destination exist, RIP chooses the most efficient route by minimizing this count. RIPv2 updates RIPv1 by including: –support for classless addressing –ability to use multicasting and broadcasting –support for authentication use ping( ) for testing routes ripLib See ripLib in the VxWorks Reference Manual for details.
® Remote Login and Telnet rlogin and telnet offer an alternative to cross- development using the Tornado target server.
® NFS Server Overview Allows remote hosts to access a targets DOS file systems using NFS protocol. By default no authentication is performed. /network components/networking protocols/network filesystems/ NFS server Add the component /network components/networking protocols/network filesystems/ NFS server. NFS server configuration supports: 1.Create a mountable DOS file system: dosFsDevInitOptionsSet (DOS_OPT_EXPORT); 2.Export DOS file system: nfsExport (name, fsId, rdOnly, notUsed); 3.Mount file system on remote host.
® VxWorks FTP Server /network components/networking protocols/network filesystems/FTP server The FTP server component is included by configuring /network components/networking protocols/network filesystems/FTP server. When target is booted, should see tFtpdTask (server daemon) running. /network components/networking protocols/network filesystems/FTP server security FTP security, which will require a valid user name and password from clients, can be included by configuring /network components/networking protocols/network filesystems/FTP server security. RLOGIN/TELNET password protection The RLOGIN/TELNET password protection component allows a single user name and encrypted password. Additional users can be added by calling loginUserAdd() in application initialization code.
® NFS vs. FTP Server NFS Advantages: –Efficient file access. –Configurable number of servers pre-spawned. FTP Advantages: –Can access file systems other than DOS. –All network hosts have FTP client.
® NFS Client Service Network File System (NFS) was developed by Sun Microsystems. Allows efficient access to files. NFS transfers and buffers files in pieces (usually 8 Kbytes). Remote file systems are mounted, then accessed as if they were local file systems. VxWorks provides NFS client and server. /network components/networking protocols/network filesystems/NFS client The NFS client component can be found under /network components/networking protocols/network filesystems/NFS client.
® NFS Client Configuration To access files on a remote machine using NFS: 0.Export servers file system: Makes the local file system available to remote host with appropriate access permissions 1.Mount the file system on the client. nfsMount (host, fileSystem, localName) 2.Set the clients authentication parameters: nfsAuthUnixSet (hostName, uid, gid, ngids,aup_gids) Defaults (NFS_GROUP_ID = 100 and NFS_USER_ID = 2001) will need to be changed. UNIX users can get the required values using: id % id uid=219(marc) gid=700(training)
® netDrv File Access Clients netDrv netDrv allows access to remote files: –Entire file read into target memory on open( ). –read( )/write( ) act on copy of file in memory. –File not written to remote host until close( ). Cant access large files (constrained by available memory). ioctl (fd, FIOSYNC, 0) is not supported. dirLib dirLib routines opendir / readdir do not work on netDrv directories. stat / fstat are only partially implemented.
® Creating network Devices STATUS netDevCreate (devName, host, protocol) devName Local name of device to create. By convention, ends with :. hostName of remote machine (from previous hostAdd( )). protocolProtocol to transfer files to/from VxWorks (0= RSH or 1= FTP). Example -> netDevCreate (ohio:, ohio, 1) -> fd = open (ohio:/u/teamN, 2)
® Executing Remote Commands VxWorks programs can invoke remote shell (RSH) commands on a UNIX host. A file descriptor called a socket is created. Can read( ) from this socket to get command output.
® UNIX: Remote Command Execution int rcmd (host, remotePort, localUser, remoteUser, cmd, pFd2) hostHost name or inet number. remotePortRemote port number to connect to, typically 514 (RSH server). localUserName of local user. remoteUserUser name on remote host. cmdShell command string to execute. stderr pFd2If non-zero, a socket for stderr is foreach I (*.o)returned through this pointer. Returns a socket file descriptor or ERROR.
® netDrv Client Services Comparison Advantages of FTP over RSH: –FTP is part of the TCP/IP protocol suite, so it is available on all networked hosts. –FTP is faster on open/close, since there is no shell delay. –FTP server is supplied with VxWorks. Advantages of RSH over FTP: –FTP clear text password goes over the network on each open( ) and close( ).
® netDrv vs. nfsDrv nfsDrvnetDrv Advantages of nfsDrv over netDrv: –Reads and writes only needed parts of the file. –Can access arbitrarily large files. –open( )/close( ) much faster. dirLib –Can use dirLib routines. –Can flush file changes with FIOSYNC. netDrvnfsDrv Advantages of netDrv over nfsDrv: –All networked hosts have an FTP server. –Easier to configure. –read( )/write( ) slightly faster.
® Summary Internet Protocol for node-to-node routing. MUX layer decouples link-layer driver and network protocol. Configuring the network –Configure host name table using hostAdd() or use DNS resolver. –Configure hosts routing table using mRouteAdd() or use RIP/OSPF. Show routines are available to troubleshoot network configuration.
® Summary DHCP allows a host to obtain IP address leases and boot parameters from a remote server. DHCP components: –DHCP Server –DHCP Relay Agent –DHCP Client rlogin (UNIX Host) and telnet support. FTP and NFS servers allows local VxWorks files to be accessed by a remote machine.
® Summary nfsDrv nfsDrv mounts remote file systems with nfsMount( ) –Reads and writes portion of remote file. –File system must be exported by remote host. netDrv netDrv devices created with netDevCreate( ). –Entire file is read into VxWorks on open( ), and not updated until close( ). –Uses either RSH (UNIX Host) or FTP for file transfer..rhosts –RSH requires name and entry in.rhosts. (UNIX Host) –FTP requires name and password. rlogin rcmd ( ) and rlogin() (UNIX Host)