IP
[Base Protocols]

RFC 791 Internet protocol version 4. More...

Collaboration diagram for IP:

Data Structures

struct  MCASTENTRY
 Multicast entry structure. More...
struct  IFNET
 Network interface structure. More...
struct  IPHDR
 Structure of an internet header. More...

Defines

#define SIOCSIFMTU   0x1001
 Set maximum transfer unit.
#define SIOCGIFMTU   0x1002
 Get maximum transfer unit.
#define SIOCSIFFLAGS   0x1003
 Set interface flags.
#define SIOCGIFFLAGS   0x1004
 Get interface flags.
#define SIOCSIFADDR   0x1005
 Set interface address.
#define SIOCGIFADDR   0x1006
 Get interface address.
#define IPVERSION   4
 IP protocol version.
#define IP_DF   0x4000
 Don't fragment flag.
#define IP_MF   0x2000
 More fragments flag.
#define IP_OFFMASK   0x1fff
 Mask for fragmenting bits.
#define IPOPT_EOL   0
 End of option list.
#define IPOPT_NOP   1
 No operation.
#define IPOPT_RR   7
 Record packet route.
#define IPOPT_TS   68
 Timestamp.
#define IPOPT_SECURITY   130
 Provide s,c,h,tcc.
#define IPOPT_LSRR   131
 Loose source route.
#define IPOPT_SATID   136
 Satnet id.
#define IPOPT_SSRR   137
 Strict source route.
#define IPOPT_OPTVAL   0
 Option identifier offset.
#define IPOPT_OLEN   1
 Option length offset.
#define IPOPT_OFFSET   2
 Offset within option.
#define IPOPT_MINOFF   4
 Minimum offset within option.
#define MAXTTL   255
 Maximum time to live (seconds).
#define IPDEFTTL   64
 Default time to live.
#define IPFRAGTTL   60
 Time to live for fragments.
#define IPTTLDEC   1
 Subtracted from time to live when forwarding.

Functions

int NutNetIfSetup (NUTDEVICE *dev, uint32_t ip_addr, uint32_t ip_mask, uint32_t gateway)
 Network interface setup.
int NutNetIfConfig (CONST char *name, void *params, uint32_t ip_addr, uint32_t ip_mask)
 Configure a network interface.
int NutNetIfConfig2 (CONST char *name, void *params, uint32_t ip_addr, uint32_t ip_mask, uint32_t gateway)
 Configure a network interface including the default gateway.
uint32_t inet_addr (CONST char *str)
 Convert decimal dotted ASCII representation into numeric IP address.
char * inet_ntoa (uint32_t addr)
 Convert numeric IP address into decimal dotted ASCII representation.
uint16_t NutIpChkSumPartial (uint16_t ics, CONST void *buf, int len)
 Calculate a partial IP checksum of a buffer.
uint16_t NutIpChkSum (uint16_t ics, CONST void *buf, int len)
 Calculates an the final IP checksum over a block of data.
uint32_t NutIpPseudoChkSumPartial (uint32_t src_addr, uint32_t dest_addr, uint8_t protocol, int len)
 Calculates the partial IP pseudo checksum.
int NutRegisterIpHandler (uint8_t prot, int(*hdlr)(NUTDEVICE *, NETBUF *))
 Register an additional Ethernet protocol handler.
void NutIpSetInputFilter (NutIpFilterFunc callbackFunc)
 Set filter function for incoming IP datagrams.
void NutIpInput (NUTDEVICE *dev, NETBUF *nb)
 Process incoming IP datagrams.
int NutIpOutput (uint8_t proto, uint32_t dest, NETBUF *nb)
 Send IP datagram.
int NutIpRouteAdd (uint32_t ip, uint32_t mask, uint32_t gate, NUTDEVICE *dev)
 Add a new entry to the IP routing table.
int NutIpRouteDelAll (NUTDEVICE *dev)
 Delete all route table entries for the given device.
int NutIpRouteDel (uint32_t ip, uint32_t mask, uint32_t gate, NUTDEVICE *dev)
 Delete the specified route table entry.
RTENTRY * NutIpRouteList (int *numEntries)
 Return an array of RTENTRY structures which contain all the current route table entries.
NUTDEVICE * NutIpRouteQuery (uint32_t ip, uint32_t *gate)
 Find a device associated with a particular IP route.

Variables

int(* ip_demux )(NUTDEVICE *, NETBUF *)
 Pointer to an optional demultiplexer.
RTENTRY * rteList

Detailed Description

RFC 791 Internet protocol version 4.

Internet Protocol checksum and related support.

Before using IP based protocols, you must have registered a network device driver like PPP or one of the supported Ethernet controller drivers.

You must also have configured the IP network interface with NutDhcpIfConfig() or NutNetIfConfig().

Typical applications do not use the IP layer directly, but call the UDP Socket API or the TCP Socket API. A Raw IP API is currently not supported.

Todo:
Configurable checksum calculation for incoming datagrams.

Define Documentation

#define SIOCSIFMTU   0x1001

Set maximum transfer unit.

Definition at line 172 of file if_var.h.

#define SIOCGIFMTU   0x1002

Get maximum transfer unit.

Definition at line 173 of file if_var.h.

#define SIOCSIFFLAGS   0x1003

Set interface flags.

Definition at line 174 of file if_var.h.

Referenced by NutNetIfConfig2().

#define SIOCGIFFLAGS   0x1004

Get interface flags.

Definition at line 175 of file if_var.h.

Referenced by NutNetIfConfig2().

#define SIOCSIFADDR   0x1005

Set interface address.

Definition at line 176 of file if_var.h.

Referenced by NutNetIfConfig2().

#define SIOCGIFADDR   0x1006

Get interface address.

Definition at line 177 of file if_var.h.

#define IPVERSION   4

IP protocol version.

Definition at line 127 of file ip.h.

Referenced by NutIpInput().

#define IP_DF   0x4000

Don't fragment flag.

Definition at line 129 of file ip.h.

#define IP_MF   0x2000

More fragments flag.

Definition at line 130 of file ip.h.

Referenced by NutIpInput().

#define IP_OFFMASK   0x1fff

Mask for fragmenting bits.

Definition at line 131 of file ip.h.

Referenced by NutIpInput().

#define IPOPT_EOL   0

End of option list.

Definition at line 165 of file ip.h.

#define IPOPT_NOP   1

No operation.

Definition at line 166 of file ip.h.

#define IPOPT_RR   7

Record packet route.

Definition at line 168 of file ip.h.

#define IPOPT_TS   68

Timestamp.

Definition at line 169 of file ip.h.

#define IPOPT_SECURITY   130

Provide s,c,h,tcc.

Definition at line 170 of file ip.h.

#define IPOPT_LSRR   131

Loose source route.

Definition at line 171 of file ip.h.

#define IPOPT_SATID   136

Satnet id.

Definition at line 172 of file ip.h.

#define IPOPT_SSRR   137

Strict source route.

Definition at line 173 of file ip.h.

#define IPOPT_OPTVAL   0

Option identifier offset.

Definition at line 175 of file ip.h.

#define IPOPT_OLEN   1

Option length offset.

Definition at line 176 of file ip.h.

#define IPOPT_OFFSET   2

Offset within option.

Definition at line 177 of file ip.h.

#define IPOPT_MINOFF   4

Minimum offset within option.

Definition at line 178 of file ip.h.

#define MAXTTL   255

Maximum time to live (seconds).

Definition at line 180 of file ip.h.

#define IPDEFTTL   64

Default time to live.

Definition at line 181 of file ip.h.

#define IPFRAGTTL   60

Time to live for fragments.

Definition at line 182 of file ip.h.

#define IPTTLDEC   1

Subtracted from time to live when forwarding.

Definition at line 183 of file ip.h.


Function Documentation

int NutNetIfSetup ( NUTDEVICE *  dev,
uint32_t  ip_addr,
uint32_t  ip_mask,
uint32_t  gateway 
)

Network interface setup.

Parameters:
dev Identifies the network device to setup.
ip_addr Specified IP address in network byte order.
ip_mask Specified IP network mask in network byte order.
gateway Optional default gateway.
Returns:
0 on success, -1 otherwise.
Note:
Typical applications do not use this function, but call NutDhcpIfConfig() or NutNetIfConfig().

Definition at line 191 of file ifconfig.c.

References confnet, ETHER_IS_UNICAST, inet_addr(), memcpy(), NutIpRouteAdd(), and NutNetSaveConfig().

Referenced by NutDhcpIfConfig(), NutIpInput(), and NutNetIfConfig2().

int NutNetIfConfig ( CONST char *  name,
void *  params,
uint32_t  ip_addr,
uint32_t  ip_mask 
)

Configure a network interface.

Devices must have been registered by NutRegisterDevice() before calling this function.

For Ethernet devices applications may alternatively call NutDhcpIfConfig(), which allows automatic configuration by DHCP or the so called ARP method.

Parameters:
name Name of the device to configure.
params Pointer to interface specific parameters. For Ethernet interfaces this parameter may be a pointer to a buffer containing the 6 byte long MAC address. This will override the MAC address stored in the non-volatile configuration memory. If this memory is uninitialized or not available, the MAC address must be specified. For PPP interfaces this parameter is ignored and should be set to zero.
ip_addr Specified IP address in network byte order. This must be a unique address within the Internet. If you do not directly communicate with other Internet hosts, you can use a locally assigned address. With PPP interfaces this may be set to 0.0.0.0, in which case the remote peer will be queried for an IP address.
ip_mask Specified IP network mask in network byte order. Typical Ethernet networks use 255.255.255.0, which allows upto 254 hosts. For PPP interfaces 255.255.255.255 is the default.
Returns:
0 on success, -1 otherwise.
Note:
The whole interface configuration has become a mess over the years and need a major redesign.

Definition at line 274 of file ifconfig.c.

References NutNetIfConfig2().

Referenced by InitEthernetDevice(), and main().

int NutNetIfConfig2 ( CONST char *  name,
void *  params,
uint32_t  ip_addr,
uint32_t  ip_mask,
uint32_t  gateway 
)

Configure a network interface including the default gateway.

Devices must have been registered by NutRegisterDevice() before calling this function.

For Ethernet devices applications may alternatively call NutDhcpIfConfig(), which allows automatic configuration by DHCP or the so called ARP method.

Parameters:
name Name of the device to configure.
params Pointer to interface specific parameters.
ip_addr Specified IP address in network byte order. This must be a unique address within the Internet. If you do not directly communicate with other Internet hosts, you can use a locally assigned address. With PPP interfaces this may be set to 0.0.0.0, in which case the remote peer will be queried for an IP address.
ip_mask Specified IP network mask in network byte order. Typical Ethernet networks use 255.255.255.0, which allows upto 254 hosts. For PPP interfaces 255.255.255.255 is the default.
gateway Specified IP address of gateway or next router in LAN.
Returns:
0 on success, -1 otherwise.
Note:
I do not like this function, because setting a gateway should be handled by NutIpRouteAdd(). It's not yet deprecated, but I recommend not to use it in application code.

Definition at line 309 of file ifconfig.c.

References _ioctl(), HDLC_SETIFNET, IFF_UP, IFT_ETHER, IFT_PPP, IFTYP_NET, memcpy(), NutDeviceLookup(), NutEventBroadcast(), NutEventWait(), NutNetIfSetup(), PPPS_OPENED, SIOCGIFFLAGS, SIOCSIFADDR, and SIOCSIFFLAGS.

Referenced by NutDhcpIfConfig(), and NutNetIfConfig().

uint32_t inet_addr ( CONST char *  str  ) 

Convert decimal dotted ASCII representation into numeric IP address.

Parameters:
str String containing the ASCII representation.
Returns:
IP address in network byte order.

Definition at line 131 of file inet.c.

Referenced by ConfigStation(), InitEthernetDevice(), main(), NutNetIfSetup(), and resolve().

char* inet_ntoa ( uint32_t  addr  ) 

Convert numeric IP address into decimal dotted ASCII representation.

Note:
This function is not thread safe. Each subsequent call will destroy the previous result. Applications should locally store the result before calling the function again or allowing other threads to call it.
Parameters:
addr IP address in network byte order.
Returns:
Pointer to a static buffer containing the ASCII representation.

Definition at line 175 of file inet.c.

Referenced by DisplayEntry(), DisplayStation(), FtpService(), main(), NutArpCacheQuery(), NutArpCacheUpdate(), NutDhcpClient(), NutDhcpIfConfig(), NutDumpIpcpOption(), NutDumpSocketList(), Scanner(), and ScanStreamHeader().

uint16_t NutIpChkSumPartial ( uint16_t  ics,
CONST void *  buf,
int  len 
)

Calculate a partial IP checksum of a buffer.

The caller must create the one's complement of the final result.

Parameters:
ics Initial checksum from previous parts.
buf Pointer to the buffer.
len Number of bytes in the buffer.
Returns:
Partial checksum in network byte order.

Definition at line 153 of file ipcsum.c.

Referenced by NutIcmpOutput(), NutIpChkSum(), NutIpPseudoChkSumPartial(), NutTcpOutput(), and NutUdpOutput().

uint16_t NutIpChkSum ( uint16_t  ics,
CONST void *  buf,
int  len 
)

Calculates an the final IP checksum over a block of data.

Unlike the partial checksum in NutIpChkSumPartial(), this function takes the one's complement of the final result, thus making it the full checksum.

Definition at line 193 of file ipcsum.c.

References NutIpChkSumPartial().

Referenced by NutIcmpOutput(), NutIgmpOutput(), NutIpOutput(), NutTcpOutput(), NutTcpReject(), and NutUdpOutput().

uint32_t NutIpPseudoChkSumPartial ( uint32_t  src_addr,
uint32_t  dest_addr,
uint8_t  protocol,
int  len 
)

Calculates the partial IP pseudo checksum.

Definition at line 214 of file ipcsum.c.

References NutIpChkSumPartial().

Referenced by NutTcpOutput(), NutTcpReject(), and NutUdpOutput().

int NutRegisterIpHandler ( uint8_t  prot,
int(*)(NUTDEVICE *, NETBUF *)  hdlr 
)

Register an additional Ethernet protocol handler.

The specified mask will be applied on the type field of incoming frames before compared with the type that had been specified for the handler. If more than one handler is registered for an incoming Ethernet frame, the handler being registered last is called first.

Each handler should return 0 if it processed the frame, in which case it is also assumed, that the handler releases the memory allocated for the NETBUF. Otherwise the handler should return -1, in which case the frame is passed to the next handler that fits.

The protocol types ETHERTYPE_IP and ETHERTYPE_ARP are pre-registered by default and processed by internal handlers after all registered handlers for that frame rejected processing. This allows to install filters on the Ethernet level.

Parameters:
type Ethernet protocol type processed by this handler.
mask Ethernet protocol type mask.
hdlr Pointer to the protocol handler function. If NULL, the handler will be temporarily disabled.
Returns:
0 on success, -1 otherwise.

Definition at line 120 of file ipdemux.c.

References calloc, and ip_demux.

Referenced by NutTcpCreateSocket(), and NutUdpCreateSocket().

void NutIpSetInputFilter ( NutIpFilterFunc  callbackFunc  ) 

Set filter function for incoming IP datagrams.

The callbackFunc is called by the IP layer on every incoming IP datagram. Thus it must not block. The implementer returns 0 for allow, -1 for deny.

It is recommended to set the filer after DHCP has done its thing, just in case your DHCP server is on a different subnet for example.

Parameters:
callbackFunc Pointer to callback function to filter IP packets. Set to 0 to disable the filter again.

Definition at line 140 of file ipin.c.

void NutIpInput ( NUTDEVICE *  dev,
NETBUF *  nb 
)

Process incoming IP datagrams.

Datagrams addressed to other destinations and datagrams whose version number is not 4 are silently discarded.

Note:
This routine is called by the Ethernet layer on incoming IP datagrams. Applications typically do not call this function.
Parameters:
dev Identifies the device that received this datagram.
nb The network buffer received.

Definition at line 165 of file ipin.c.

References htons, ICMP_UNREACH, ICMP_UNREACH_PROTOCOL, IN_MULTICAST, INADDR_BROADCAST, ip_demux, IP_MF, IP_OFFMASK, IPPROTO_ICMP, IPPROTO_IGMP, IPVERSION, NBAF_UNICAST, ntohs, NutIcmpInput(), NutIcmpResponse(), NutIgmpInput(), NutNetBufFree(), and NutNetIfSetup().

Referenced by NutEtherInput(), and NutPppInput().

int NutIpOutput ( uint8_t  proto,
uint32_t  dest,
NETBUF *  nb 
)

Send IP datagram.

Route an IP datagram to the proper interface.

The function will not return until the data has been stored in the network device hardware for transmission. If the device is not ready for transmitting a new packet, the calling thread will be suspended until the device becomes ready again. If the hardware address of the target host needs to be resolved the function will be suspended too.

Parameters:
proto Protocol type.
dest Destination IP address. The function will determine the proper network interface by checking the routing table. It will also perform any neccessary hardware address resolution.
nb Network buffer structure containing the datagram. This buffer will be released if the function returns an error.
Returns:
0 on success, -1 otherwise.
Bug:
Broadcasts to multiple network devices will fail after the first device returns an error.

Definition at line 182 of file ipout.c.

References ETHERTYPE_IP, htons, IFT_ETHER, IFT_PPP, IFTYP_NET, IPPROTO_IGMP, memset(), NBAF_NETWORK, NutArpCacheQuery(), nutDeviceList, NutIpChkSum(), NutIpRouteQuery(), NutNetBufAlloc(), NutNetBufFree(), and PPP_IP.

Referenced by NutIcmpOutput(), NutIgmpOutput(), NutTcpOutput(), NutTcpReject(), NutTcpStateRetranTimeout(), and NutUdpOutput().

int NutIpRouteAdd ( uint32_t  ip,
uint32_t  mask,
uint32_t  gate,
NUTDEVICE *  dev 
)

Add a new entry to the IP routing table.

Note, that there is currently no support for detecting duplicates. Anyway, newer entries will be found first, because they are inserted in front of older entries. However, this works only for equal masks, i.e. new network routes will never overwrite old host routes.

Parameters:
ip Network or host IP address to be routed. Set 0 for default route.
mask Mask for this entry. -1 for host routes, 0 for default or net mask for net routes.
gate Route through this gateway, otherwise 0.
dev Network interface to use.
Returns:
0 on success, -1 otherwise.

Definition at line 174 of file route.c.

References malloc, and rteList.

Referenced by InitEthernetDevice(), main(), and NutNetIfSetup().

int NutIpRouteDelAll ( NUTDEVICE *  dev  ) 

Delete all route table entries for the given device.

Parameters:
dev Pointer to the device. If NULL, it deletes all route table entries.
Returns:
0 on success, -1 otherwise.

Definition at line 212 of file route.c.

References free, and rteList.

int NutIpRouteDel ( uint32_t  ip,
uint32_t  mask,
uint32_t  gate,
NUTDEVICE *  dev 
)

Delete the specified route table entry.

All fields must exactly match an existing entry.

Parameters:
ip Network or host IP address of the route entry.
mask Mask for this entry. -1 for host routes, 0 for default or net mask for net routes.
gate Route through this gateway, 0 for default gate.
dev Network interface to use.
Returns:
0 on success, -1 otherwise.

Definition at line 245 of file route.c.

References free, and rteList.

RTENTRY* NutIpRouteList ( int *  numEntries  ) 

Return an array of RTENTRY structures which contain all the current route table entries.

The calling function is responsible for deleting the array.

Parameters:
numEntries Points to an integer, which receives the length of the array.
Returns:
Pointer to the array. Will be NULL in case of an error.

Definition at line 272 of file route.c.

References malloc, memcpy(), and rteList.

NUTDEVICE* NutIpRouteQuery ( uint32_t  ip,
uint32_t gate 
)

Find a device associated with a particular IP route.

Gateway routes will be automatically resolved up to four levels of redirection.

Parameters:
ip IP address to find a route for, given in network byte order.
gate Points to a buffer which optionally receives the IP address of a gateway. The pointer may be NULL, if the caller is not interested in this information.
Returns:
Pointer to the interface structure or NULL if no route was found.

Definition at line 347 of file route.c.

References rteList.

Referenced by main(), NutIpOutput(), NutTcpConnect(), and NutUdpOutput().


Variable Documentation

int(* ip_demux)(NUTDEVICE *, NETBUF *)

Pointer to an optional demultiplexer.

This pointer will be set on the first call to NutRegisterIpHandler().

Definition at line 150 of file ipin.c.

Referenced by NutIpInput(), and NutRegisterIpHandler().

RTENTRY* rteList

Linked list of routing entries.

Definition at line 155 of file route.c.

Referenced by NutIpRouteAdd(), NutIpRouteDel(), NutIpRouteDelAll(), NutIpRouteList(), and NutIpRouteQuery().


© 2000-2007 by egnite Software GmbH - visit http://www.ethernut.de/