2e6d0815b2
RFC 1191
When a router is unable to forward a datagram because it exceeds the
MTU of the next-hop network and its Don't Fragment bit is set, the
router is required to return an ICMP Destination Unreachable message
to the source of the datagram, with the Code indicating
"fragmentation needed and DF set". To support the Path MTU Discovery
technique specified in this memo, the router MUST include the MTU of
that next-hop network in the low-order 16 bits of the ICMP header
field that is labelled "unused" in the ICMP specification [7]. The
high-order 16 bits remain unused, and MUST be set to zero. Thus, the
message has the following format:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 3 | Code = 4 | Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| unused = 0 | Next-Hop MTU |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Internet Header + 64 bits of Original Datagram Data |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
RFC 1185
Packet Too Big Message
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Code | Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MTU |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| As much of invoking packet |
+ as will fit without the ICMPv6 packet +
| exceeding 576 octets |
IPv6 Fields:
Destination Address
Copied from the Source Address field of the invoking
packet.
ICMPv6 Fields:
Type 2
Code 0
MTU The Maximum Transmission Unit of the next-hop link.
Description
A Packet Too Big MUST be sent by a router in response to a packet
that it cannot forward because the packet is larger than the MTU of
the outgoing link. The information in this message is used as part
of the Path MTU Discovery process [RFC-1191].
Signed-off-by: wangchen <wangchen41@xiaomi.com>
448 lines
14 KiB
C
448 lines
14 KiB
C
/****************************************************************************
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* net/icmp/icmp.h
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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#ifndef __NET_ICMP_ICMP_H
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#define __NET_ICMP_ICMP_H
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <sys/types.h>
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#include <stdint.h>
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#include <assert.h>
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#include <nuttx/mm/iob.h>
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#include <nuttx/net/ip.h>
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#include <nuttx/net/net.h>
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#include <nuttx/net/netdev.h>
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#if defined(CONFIG_NET_ICMP) && !defined(CONFIG_NET_ICMP_NO_STACK)
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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#define NET_ICMP_HAVE_STACK 1
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/* Allocate/free an ICMP data callback */
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#define icmp_callback_alloc(dev, conn) \
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devif_callback_alloc((dev), &(conn)->sconn.list, &(conn)->sconn.list_tail)
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#define icmp_callback_free(dev, conn, cb) \
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devif_conn_callback_free((dev), (cb), &(conn)->sconn.list, &(conn)->sconn.list_tail)
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/****************************************************************************
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* Public types
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****************************************************************************/
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struct socket; /* Forward reference */
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struct sockaddr; /* Forward reference */
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struct pollfd; /* Forward reference */
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#ifdef CONFIG_NET_ICMP_SOCKET
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/* Representation of a IPPROTO_ICMP socket connection */
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struct devif_callback_s; /* Forward reference */
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/* This is a container that holds the poll-related information */
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struct icmp_poll_s
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{
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FAR struct socket *psock; /* IPPROTO_ICMP socket structure */
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FAR struct pollfd *fds; /* Needed to handle poll events */
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FAR struct devif_callback_s *cb; /* Needed to teardown the poll */
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};
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struct icmp_conn_s
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{
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/* Common prologue of all connection structures. */
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struct socket_conn_s sconn;
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/* ICMP-specific content follows */
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uint16_t id; /* ICMP ECHO request ID */
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uint8_t nreqs; /* Number of requests with no response received */
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uint8_t crefs; /* Reference counts on this instance */
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/* The device that the ICMP request was sent on */
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FAR struct net_driver_s *dev; /* Needed to free the callback structure */
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/* ICMP response read-ahead list. A singly linked list of type struct
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* iob_qentry_s where the ICMP read-ahead data for the current ID is
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* retained.
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*/
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struct iob_queue_s readahead; /* Read-ahead buffering */
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/* The following is a list of poll structures of threads waiting for
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* socket events.
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*/
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struct icmp_poll_s pollinfo[CONFIG_NET_ICMP_NPOLLWAITERS];
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};
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#endif
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#ifdef CONFIG_NET_IPv4
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struct icmp_pmtu_entry
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{
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in_addr_t daddr;
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uint16_t pmtu;
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clock_t time;
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};
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#endif
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/****************************************************************************
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* Public Data
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****************************************************************************/
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#ifdef __cplusplus
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# define EXTERN extern "C"
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extern "C"
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{
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#else
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# define EXTERN extern
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#endif
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#ifdef CONFIG_NET_ICMP_SOCKET
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/* PF_INET socket address family, IPPROTO_ICMP protocol interface */
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EXTERN const struct sock_intf_s g_icmp_sockif;
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#endif
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/****************************************************************************
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* Public Function Prototypes
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****************************************************************************/
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/****************************************************************************
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* Name: icmp_input
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*
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* Description:
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* Handle incoming ICMP input
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*
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* Input Parameters:
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* dev - The device driver structure containing the received ICMP
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* packet
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*
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* Returned Value:
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* None
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*
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* Assumptions:
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* The network is locked.
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*
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****************************************************************************/
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void icmp_input(FAR struct net_driver_s *dev);
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/****************************************************************************
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* Name: icmp_sock_initialize
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*
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* Description:
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* Initialize the IPPROTO_ICMP socket connection structures. Called once
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* and only from the network initialization layer.
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*
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****************************************************************************/
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#ifdef CONFIG_NET_ICMP_SOCKET
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void icmp_sock_initialize(void);
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#endif
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/****************************************************************************
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* Name: icmp_alloc
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*
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* Description:
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* Allocate a new, uninitialized IPPROTO_ICMP socket connection structure.
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* This is normally something done by the implementation of the socket()
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* interface.
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*
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****************************************************************************/
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#ifdef CONFIG_NET_ICMP_SOCKET
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FAR struct icmp_conn_s *icmp_alloc(void);
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#endif
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/****************************************************************************
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* Name: icmp_free
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*
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* Description:
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* Free a IPPROTO_ICMP socket connection structure that is no longer in
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* use. This should be done by the implementation of close().
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*
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****************************************************************************/
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#ifdef CONFIG_NET_ICMP_SOCKET
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void icmp_free(FAR struct icmp_conn_s *conn);
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#endif
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/****************************************************************************
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* Name: icmp_active()
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*
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* Description:
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* Find a connection structure that is the appropriate connection to be
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* used with the provided ECHO request ID.
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*
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* Assumptions:
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* This function is called from network logic at with the network locked.
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*
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****************************************************************************/
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#ifdef CONFIG_NET_ICMP_SOCKET
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FAR struct icmp_conn_s *icmp_active(uint16_t id);
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#endif
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/****************************************************************************
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* Name: icmp_nextconn
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*
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* Description:
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* Traverse the list of allocated packet connections
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*
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* Assumptions:
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* This function is called from network logic at with the network locked.
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*
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****************************************************************************/
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#ifdef CONFIG_NET_ICMP_SOCKET
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FAR struct icmp_conn_s *icmp_nextconn(FAR struct icmp_conn_s *conn);
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#endif
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/****************************************************************************
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* Name: icmp_findconn
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*
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* Description:
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* Find an ICMP connection structure that is expecting a ICMP ECHO response
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* with this ID from this device
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*
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* Assumptions:
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* This function is called from network logic at with the network locked.
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*
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****************************************************************************/
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#ifdef CONFIG_NET_ICMP_SOCKET
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FAR struct icmp_conn_s *icmp_findconn(FAR struct net_driver_s *dev,
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uint16_t id);
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#endif
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/****************************************************************************
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* Name: icmp_poll
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*
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* Description:
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* Poll a device "connection" structure for availability of ICMP TX data
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*
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* Input Parameters:
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* dev - The device driver structure to use in the send operation
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* conn - A pointer to the ICMP connection structure
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*
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* Returned Value:
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* None
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*
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* Assumptions:
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* The network is locked.
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*
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****************************************************************************/
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#ifdef CONFIG_NET_ICMP_SOCKET
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void icmp_poll(FAR struct net_driver_s *dev, FAR struct icmp_conn_s *conn);
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#endif
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/****************************************************************************
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* Name: icmp_sendmsg
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*
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* Description:
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* Implements the sendmsg() operation for the case of the IPPROTO_ICMP
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* socket. The 'buf' parameter points to a block of memory that includes
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* an ICMP request header, followed by any payload that accompanies the
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* request. The 'len' parameter includes both the size of the ICMP header
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* and the following payload.
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*
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* Input Parameters:
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* psock A pointer to a NuttX-specific, internal socket structure
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* msg Message to send
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* flags Send flags
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*
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* Returned Value:
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* On success, returns the number of characters sent. On error, a negated
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* errno value is returned (see sendmsg() for the list of appropriate error
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* values.
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*
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****************************************************************************/
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#ifdef CONFIG_NET_ICMP_SOCKET
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ssize_t icmp_sendmsg(FAR struct socket *psock, FAR struct msghdr *msg,
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int flags);
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#endif
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/****************************************************************************
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* Name: icmp_recvmsg
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*
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* Description:
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* Implements the socket recvfrom interface for the case of the AF_INET
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* data gram socket with the IPPROTO_ICMP protocol. icmp_recvmsg()
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* receives ICMP ECHO replies for the a socket.
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*
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* If msg_name is not NULL, and the underlying protocol provides the source
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* address, this source address is filled in. The argument 'msg_namelen' is
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* initialized to the size of the buffer associated with msg_name, and
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* modified on return to indicate the actual size of the address stored
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* there.
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*
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* Input Parameters:
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* psock A pointer to a NuttX-specific, internal socket structure
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* msg Buffer to receive the message
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* flags Receive flags
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*
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* Returned Value:
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* On success, returns the number of characters received. If no data is
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* available to be received and the peer has performed an orderly shutdown,
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* recvmsg() will return 0. Otherwise, on errors, a negated errno value is
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* returned (see recvmsg() for the list of appropriate error values).
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*
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****************************************************************************/
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#ifdef CONFIG_NET_ICMP_SOCKET
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ssize_t icmp_recvmsg(FAR struct socket *psock, FAR struct msghdr *msg,
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int flags);
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#endif
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/****************************************************************************
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* Name: icmp_pollsetup
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*
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* Description:
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* Setup to monitor events on one ICMP socket
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*
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* Input Parameters:
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* psock - The IPPROTO_ICMP socket of interest
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* fds - The structure describing the events to be monitored, OR NULL if
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* this is a request to stop monitoring events.
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*
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* Returned Value:
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* 0: Success; Negated errno on failure
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*
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****************************************************************************/
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#ifdef CONFIG_NET_ICMP_SOCKET
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int icmp_pollsetup(FAR struct socket *psock, FAR struct pollfd *fds);
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#endif
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/****************************************************************************
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* Name: icmp_pollteardown
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*
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* Description:
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* Teardown monitoring of events on an ICMP socket
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*
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* Input Parameters:
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* psock - The IPPROTO_ICMP socket of interest
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* fds - The structure describing the events to be monitored, OR NULL if
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* this is a request to stop monitoring events.
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*
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* Returned Value:
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* 0: Success; Negated errno on failure
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*
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****************************************************************************/
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#ifdef CONFIG_NET_ICMP_SOCKET
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int icmp_pollteardown(FAR struct socket *psock, FAR struct pollfd *fds);
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#endif
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/****************************************************************************
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* Name: icmp_reply
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*
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* Description:
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* Send an ICMP message in response to a situation
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* RFC 1122: 3.2.2 MUST send at least the IP header and 8 bytes of header.
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* MAY send more (we do).
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* MUST NOT change this header information.
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* MUST NOT reply to a multicast/broadcast IP address.
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* MUST NOT reply to a multicast/broadcast MAC address.
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* MUST reply to only the first fragment.
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*
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* Input Parameters:
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* dev - The device driver structure containing the received packet
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* type - ICMP Message Type, eg. ICMP_DEST_UNREACHABLE
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* code - ICMP Message Code, eg. ICMP_PORT_UNREACH
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*
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* Returned Value:
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* None
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*
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****************************************************************************/
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void icmp_reply(FAR struct net_driver_s *dev, int type, int code);
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/****************************************************************************
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* Name: icmp_ioctl
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*
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* Description:
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* This function performs icmp specific ioctl() operations.
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*
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* Parameters:
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* conn The ICMP connection of interest
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* cmd The ioctl command
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* arg The argument of the ioctl cmd
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*
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****************************************************************************/
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#ifdef CONFIG_NET_ICMP_SOCKET
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int icmp_ioctl(FAR struct socket *psock, int cmd, unsigned long arg);
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#endif
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/****************************************************************************
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* Name: icmpv4_find_pmtu_entry
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*
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* Description:
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* Search for a ipv4 destination cache entry
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*
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* Parameters:
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* destipaddr the IPv4 address of the destination
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*
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* Return:
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* not null is success; null is failure
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****************************************************************************/
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FAR struct icmp_pmtu_entry *icmpv4_find_pmtu_entry(in_addr_t destipaddr);
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/****************************************************************************
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* Name: icmpv4_add_pmtu_entry
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*
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* Description:
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* Create a new ipv4 destination cache entry. If no unused entry is found,
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* will recycle oldest entry
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*
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* Parameters:
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* destipaddr the IPv4 address of the destination
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* mtu MTU
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*
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* Return:
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* void
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****************************************************************************/
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void icmpv4_add_pmtu_entry(in_addr_t destipaddr, int mtu);
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#undef EXTERN
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#ifdef __cplusplus
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}
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#endif
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#endif /* CONFIG_NET_ICMP && !CONFIG_NET_ICMP_NO_STACK */
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#endif /* __NET_ICMP_ICMP_H */
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