+The following codes are defined:
+.Bl -column x xxxxxxxxxxxx xxxxxxxx -offset indent
+.It Sy Num Ta Sy Abbrev. Ta Sy Type Ta
+.Sy Description
+.It 0 Ta noroute-unr Ta unreach Ta "No route to destination"
+.It 1 Ta admin-unr Ta unreach Ta "Administratively prohibited"
+.It 2 Ta beyond-unr Ta unreach Ta "Beyond scope of source address"
+.It 2 Ta notnbr-unr Ta unreach Ta "Not a neighbor (obselete)"
+.It 3 Ta addr-unr Ta unreach Ta "Address unreachable"
+.It 4 Ta port-unr Ta unreach Ta "Port unreachable"
+.It 0 Ta transit Ta timex Ta "Time exceeded in transit"
+.It 1 Ta reassemb Ta timex Ta "Time exceeded in reassembly"
+.It 0 Ta badhead Ta paramprob Ta "Erroneous header field"
+.It 1 Ta nxthdr Ta paramprob Ta "Unrecognized next header"
+.It 2 Ta "" Ta redir Ta "Unrecognized option"
+.It 0 Ta redironlink Ta redir Ta "Redirection to on-link node"
+.It 1 Ta redirrouter Ta redir Ta "Redirection to better router"
+.El
+.Ss Headers
+All ICMPv6 messages are prefixed with an ICMPv6 header.
+This header corresponds to the
+.Vt icmp6_hdr
+structure and has the following definition:
+.Bd -literal -offset indent
+struct icmp6_hdr {
+ u_int8_t icmp6_type; /* type field */
+ u_int8_t icmp6_code; /* code field */
+ u_int16_t icmp6_cksum; /* checksum field */
+ union {
+ u_int32_t icmp6_un_data32[1]; /* type-specific */
+ u_int16_t icmp6_un_data16[2]; /* type-specific */
+ u_int8_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*/
+.Ed
+.Pp
+.Va icmp6_type
+describes the type of the message.
+Suitable values are defined in
+.Aq Pa netinet/icmp6.h .
+.Va icmp6_code
+describes the sub-type of the message and depends on
+.Va icmp6_type .
+.Va 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.
+.Ss Filters
+Because of the extra functionality of ICMPv6 in comparison to ICMPv4,
+a larger number of messages may be potentially received on an ICMPv6
+socket.
+Input filters may therefore be used to restrict input to a subset of the
+incoming ICMPv6 messages so only interesting messages are returned by the
+.Xr recv 2
+family of calls to an application.
projects / apple / xnu.git / blobdiff