ICMP
[Base Protocols]

Collaboration diagram for ICMP:

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Detailed Description

RFC 792 Internet Control Message Protocol.

Provides routing, diagnostic and error functionality for IP. Although ICMP messages are encapsulated within IP datagrams, ICMP processing is considered to be part of the IP layer.

There is currently no API support for this layer.

Functions
void	NutIcmpInput (NUTDEVICE *dev, NETBUF *nb)
	Handle incoming ICMP packets.
int	NutIcmpOutput (u_char type, u_long dest, NETBUF *nb)
	Send an ICMP datagram.
int	NutIcmpReply (u_char type, u_char code, u_long spec, u_long dest, NETBUF *nb)
	Send an ICMP message to a given destination.
int	NutIcmpResponse (u_char type, u_char code, u_long spec, NETBUF *nb)
	Send an ICMP message as a response to a given destination.

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Function Documentation

void NutIcmpInput (  NUTDEVICE *  dev, NETBUF *  nb )

Handle incoming ICMP packets. Incoming ICMP packets are processed in the background. NutNet currently handles echo request and destination unreachable packets. Any other packet type is silently discarded. Note: This routine is called by the IP layer on incoming ICMP datagrams. Applications typically do not call this function. Parameters: dev  Identifies the device that received the packet. nb  Pointer to a network buffer structure containing the ICMP datagram.

int NutIcmpOutput (  u_char  type, u_long  dest, NETBUF *  nb )

Send an ICMP datagram. Known ICMP types are: ICMP_ECHOREPLY Echo reply ICMP_UNREACH Destination unreachable ICMP_SOURCEQUENCH Packet lost ICMP_REDIRECT Shorter route ICMP_ECHO Echo reply ICMP_ROUTERADVERT Router advertisement ICMP_ROUTERSOLICIT Router solicitation ICMP_TIMXCEED Time exceeded ICMP_PARAMPROB Bad IP header ICMP_TSTAMP Timestamp request ICMP_TSTAMPREPLY Timestamp reply ICMP_IREQ Information request ICMP_IREQREPLY Information reply ICMP_MASKREQ Address mask request ICMP_MASKREPLY Address mask reply Parameters: type  Type of the ICMP message. dest  Destination IP address. nb  Network buffer structure containing the datagram. Returns: 0 on success, -1 otherwise.

int NutIcmpReply (  u_char  type, u_char  code, u_long  spec, u_long  dest, NETBUF *  nb )

Send an ICMP message to a given destination. Parameters: type  Type of the ICMP message. See NutIcmpOutput() for a list of valid types. code  Type subcode. spec  Type specific data item. dest  IP address of the target. nb  Network buffer structure containing the message to be sent. The structure must have been allocated by a previous call NutNetBufAlloc() and will be freed if this function returns with an error. Returns: 0 on success, -1 otherwise.

int NutIcmpResponse (  u_char  type, u_char  code, u_long  spec, NETBUF *  nb )

Send an ICMP message as a response to a given destination. Parameters: type  Type of the ICMP message. See NutIcmpOutput() for a list of valid types. code  Type subcode. spec  Type specific data item. nb  Network buffer structure containing the previously recevied network packet. According to RFC792 the complete ip header and the first 8 bytes of the transport netbuf is used as the application data for the response. If this function returns with an error, the buffer is freed. The destination addess is taken from the ip header. Returns: 0 on success, -1 otherwise.

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