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/*
Copyright (C) 2001-2025 Free Software Foundation, Inc.
This file is part of GNU Inetutils.
GNU Inetutils is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or (at
your option) any later version.
GNU Inetutils is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see `http://www.gnu.org/licenses/'. */
/*
* Structure of an icmp header.
*/
typedef struct icmp_header icmphdr_t;
struct icmp_header
{
unsigned char icmp_type; /* type of message, see below */
unsigned char icmp_code; /* type sub code */
unsigned short icmp_cksum; /* ones complement cksum of struct */
union
{
unsigned char ih_pptr; /* ICMP_PARAMPROB */
struct in_addr ih_gwaddr; /* ICMP_REDIRECT */
struct ih_idseq
{
unsigned short icd_id;
unsigned short icd_seq;
} ih_idseq;
int ih_void;
/* ICMP_UNREACH_NEEDFRAG -- Path MTU discovery as per rfc 1191 */
struct ih_pmtu
{
unsigned short ipm_void;
unsigned short ipm_nextmtu;
} ih_pmtu;
/* ICMP_ROUTERADV -- RFC 1256 */
struct ih_rtradv
{
unsigned char irt_num_addrs; /* Number of addresses following the msg */
unsigned char irt_wpa; /* Address Entry Size (32-bit words) */
unsigned short irt_lifetime; /* Lifetime */
} ih_rtradv;
} icmp_hun;
#define icmp_pptr icmp_hun.ih_pptr
#define icmp_gwaddr icmp_hun.ih_gwaddr
#define icmp_id icmp_hun.ih_idseq.icd_id
#define icmp_seq icmp_hun.ih_idseq.icd_seq
#define icmp_void icmp_hun.ih_void
#define icmp_pmvoid icmp_hun.ih_pmtu.ipm_void
#define icmp_nextmtu icmp_hun.ih_pmtu.ipm_nextmtu
#define icmp_num_addrs icmp_hun.ih_rtradv.irt_num_addrs
#define icmp_wpa icmp_hun.ih_rtradv.irt_wpa
#define icmp_lifetime icmp_hun.ih_rtradv.irt_lifetime
union
{
struct id_ts /* ICMP_TIMESTAMP, ICMP_TIMESTAMPREPLY */
{
n_time its_otime; /* Originate timestamp */
n_time its_rtime; /* Receive timestamp */
n_time its_ttime; /* Transmit timestamp */
} id_ts;
struct id_ip /* Original IP header */
{
struct ip idi_ip;
/* options and then 64 bits of data */
} id_ip;
unsigned long id_mask; /* ICMP_ADDRESS, ICMP_ADDRESSREPLY */
char id_data[1];
} icmp_dun;
#define icmp_otime icmp_dun.id_ts.its_otime
#define icmp_rtime icmp_dun.id_ts.its_rtime
#define icmp_ttime icmp_dun.id_ts.its_ttime
#define icmp_ip icmp_dun.id_ip.idi_ip
#define icmp_mask icmp_dun.id_mask
#define icmp_data icmp_dun.id_data
};
#define ICMP_ECHOREPLY 0 /* Echo Reply */
#define ICMP_DEST_UNREACH 3 /* Destination Unreachable */
/* Codes for ICMP_DEST_UNREACH. */
#define ICMP_NET_UNREACH 0 /* Network Unreachable */
#define ICMP_HOST_UNREACH 1 /* Host Unreachable */
#define ICMP_PROT_UNREACH 2 /* Protocol Unreachable */
#define ICMP_PORT_UNREACH 3 /* Port Unreachable */
#define ICMP_FRAG_NEEDED 4 /* Fragmentation Needed/DF set */
#define ICMP_SR_FAILED 5 /* Source Route failed */
#define ICMP_NET_UNKNOWN 6
#define ICMP_HOST_UNKNOWN 7
#define ICMP_HOST_ISOLATED 8
#define ICMP_NET_ANO 9
#define ICMP_HOST_ANO 10
#define ICMP_NET_UNR_TOS 11
#define ICMP_HOST_UNR_TOS 12
#define ICMP_PKT_FILTERED 13 /* Packet filtered */
#define ICMP_PREC_VIOLATION 14 /* Precedence violation */
#define ICMP_PREC_CUTOFF 15 /* Precedence cut off */
#define NR_ICMP_UNREACH 15 /* total subcodes */
#define ICMP_SOURCE_QUENCH 4 /* Source Quench */
#define ICMP_REDIRECT 5 /* Redirect (change route) */
/* Codes for ICMP_REDIRECT. */
#define ICMP_REDIR_NET 0 /* Redirect Net */
#define ICMP_REDIR_HOST 1 /* Redirect Host */
#define ICMP_REDIR_NETTOS 2 /* Redirect Net for TOS */
#define ICMP_REDIR_HOSTTOS 3 /* Redirect Host for TOS */
#define ICMP_ECHO 8 /* Echo Request */
#define ICMP_ROUTERADV 9 /* Router Advertisement -- RFC 1256 */
#define ICMP_ROUTERDISCOVERY 10 /* Router Discovery -- RFC 1256 */
#define ICMP_TIME_EXCEEDED 11 /* Time Exceeded */
/* Codes for TIME_EXCEEDED. */
#define ICMP_EXC_TTL 0 /* TTL count exceeded */
#define ICMP_EXC_FRAGTIME 1 /* Fragment Reass time exceeded */
#define ICMP_PARAMETERPROB 12 /* Parameter Problem */
#define ICMP_TIMESTAMP 13 /* Timestamp Request */
#define ICMP_TIMESTAMPREPLY 14 /* Timestamp Reply */
#define ICMP_INFO_REQUEST 15 /* Information Request */
#define ICMP_INFO_REPLY 16 /* Information Reply */
#define ICMP_ADDRESS 17 /* Address Mask Request */
#define ICMP_ADDRESSREPLY 18 /* Address Mask Reply */
#define NR_ICMP_TYPES 18
#define MAXIPLEN 60
#define MAXICMPLEN 76
#define ICMP_MINLEN 8 /* abs minimum */
#define ICMP_TSLEN (8 + 3 * sizeof (n_time)) /* timestamp */
#define ICMP_MASKLEN 12 /* address mask */
#define ICMP_ADVLENMIN (8 + sizeof (struct ip) + 8) /* min */
#define ICMP_ADVLEN(p) (8 + ((p)->icmp_ip.ip_hl << 2) + 8)
/* N.B.: must separately check that ip_hl >= 5 */
unsigned short icmp_cksum (unsigned char *addr, int len);
int icmp_generic_encode (unsigned char *buffer, size_t bufsize, int type,
int ident, int seqno);
int icmp_generic_decode (unsigned char *buffer, size_t bufsize,
struct ip **ipp, icmphdr_t ** icmpp);
int icmp_echo_encode (unsigned char *buffer, size_t bufsize, int ident,
int seqno);
int icmp_echo_decode (unsigned char *buffer, size_t bufsize, struct ip **ip,
icmphdr_t ** icmp);
int icmp_timestamp_encode (unsigned char *buffer, size_t bufsize, int ident,
int seqno);
int icmp_address_encode (unsigned char *buffer, size_t bufsize, int ident,
int seqno);
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