int
socket(
AF_INET6
, SOCK_RAW
, IPPROTO_ICMPV6
)
The
proto
parameter to the
socket(2)
call to create an ICMPv6 socket may be obtained from
getprotobyname(3).
ICMPv6 sockets are connectionless, and are normally used with the
sendto(2)
and
recvfrom(2)
calls, though the
connect(2)
call may also be used to fix the destination for future packets
(in which case
read(2)
or
recv(2)
and
write(2)
or
send(2)
system calls may be used).
Outgoing packets automatically have an IPv6 header prepended to them (based on the destination address). Incoming packets on the socket are received with the IPv6 header and any extension headers removed.
Num | Abbrev. | Description |
1 | unreach | Destination unreachable |
2 | toobig | Packet too big |
3 | timex | Time exceeded |
4 | paramprob | Invalid IPv6 header |
128 | echoreq | Echo service request |
129 | echorep | Echo service reply |
130 | groupqry | Group membership query |
130 | listqry | Multicast listener query |
131 | grouprep | Group membership report |
131 | listenrep | Multicast listener report |
132 | groupterm | Group membership termination |
132 | listendone | Multicast listerner done |
133 | routersol | Router solicitation |
134 | routeradv | Router advertisement |
135 | neighbrsol | Neighbor solicitation |
136 | neighbradv | Neighbor advertisement |
137 | redir | Shorter route exists |
138 | routrrenum | Route renumbering |
139 | fqdnreq | FQDN query |
139 | niqry | Node information query |
139 | wrureq | Who-are-you request |
140 | fqdnrep | FQDN reply |
140 | nirep | Node information reply |
140 | wrurep | Who-are-you reply |
200 | mtraceresp | mtrace response |
201 | mtrace | mtrace messages |
The following codes are defined:
Num | Abbrev. | Type | Description |
0 | noroute-unr | unreach | No route to destination |
1 | admin-unr | unreach | Administratively prohibited |
2 | beyond-unr | unreach | Beyond scope of source address |
2 | notnbr-unr | unreach | Not a neighbor (obselete) |
3 | addr-unr | unreach | Address unreachable |
4 | port-unr | unreach | Port unreachable |
0 | transit | timex | Time exceeded in transit |
1 | reassemb | timex | Time exceeded in reassembly |
0 | badhead | paramprob | Erroneous header field |
1 | nxthdr | paramprob | Unrecognized next header |
2 | redir | Unrecognized option | |
0 | redironlink | redir | Redirection to on-link node |
1 | redirrouter | redir | Redirection to better router |
struct icmp6_hdr {
uint8_t icmp6_type; /* type field */
uint8_t icmp6_code; /* code field */
uint16_t icmp6_cksum; /* checksum field */
union {
uint32_t icmp6_un_data32[1]; /* type-specific */
uint16_t icmp6_un_data16[2]; /* type-specific */
uint8_t icmp6_un_data8[4]; /* type-specific */
} icmp6_dataun;
} __packed;
#define icmp6_data32 icmp6_dataun.icmp6_un_data32
#define icmp6_data16 icmp6_dataun.icmp6_un_data16
#define icmp6_data8 icmp6_dataun.icmp6_un_data8
#define icmp6_pptr icmp6_data32[0] /* parameter prob */
#define icmp6_mtu icmp6_data32[0] /* packet too big */
#define icmp6_id icmp6_data16[0] /* echo request/reply */
#define icmp6_seq icmp6_data16[1] /* echo request/reply */
#define icmp6_maxdelay icmp6_data16[0] /* mcast group membership*/
icmp6_type
describes the type of the message.
Suitable values are defined in
<netinet/icmp6.h
>.
icmp6_code
describes the sub-type of the message and depends on
icmp6_type.
icmp6_cksum
contains the checksum for the message and is filled in by the
kernel on outgoing messages.
The other fields are used for type-specific purposes.
The structure may be used to refine the input message set according to the ICMPv6 type. By default, all messages types are allowed on newly created raw ICMPv6 sockets. The following macros may be used to refine the input set:
struct icmp6_filter *filterp
)
struct icmp6_filter *filterp
)
int type
, struct icmp6_filter *filterp
)
type
.
filterp
is modified to allow such messages.
int type
, struct icmp6_filter *filterp
)
type
.
filterp
is modified to ignore such messages.
int type
, const struct icmp6_filter *filterp
)
int type
, const struct icmp6_filter *filterp
)
The
getsockopt(2)
and
setsockopt(2)
calls may be used to obtain and install the filter on ICMPv6 sockets at
option level
IPPROTO_ICMPV6
and name
ICMPV6_FILTER
with a pointer to the
structure as the option value.