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diff --git a/man7/ipv6.7 b/man7/ipv6.7 new file mode 100644 index 0000000..e6f9d54 --- /dev/null +++ b/man7/ipv6.7 @@ -0,0 +1,416 @@ +.\" SPDX-License-Identifier: Linux-man-pages-1-para +.\" +.\" This man page is Copyright (C) 2000 Andi Kleen <ak@muc.de>. +.\" +.\" $Id: ipv6.7,v 1.3 2000/12/20 18:10:31 ak Exp $ +.\" +.\" The following socket options are undocumented +.\" All of the following are from: +.\" commit 333fad5364d6b457c8d837f7d05802d2aaf8a961 +.\" Author: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> +.\" Support several new sockopt / ancillary data in Advanced API (RFC3542). +.\" IPV6_2292PKTINFO (2.6.14) +.\" Formerly IPV6_PKTINFO +.\" IPV6_2292HOPOPTS (2.6.14) +.\" Formerly IPV6_HOPOPTS, which is documented +.\" IPV6_2292DSTOPTS (2.6.14) +.\" Formerly IPV6_DSTOPTS, which is documented +.\" IPV6_2292RTHDR (2.6.14) +.\" Formerly IPV6_RTHDR, which is documented +.\" IPV6_2292PKTOPTIONS (2.6.14) +.\" Formerly IPV6_PKTOPTIONS +.\" IPV6_2292HOPLIMIT (2.6.14) +.\" Formerly IPV6_HOPLIMIT, which is documented +.\" +.\" IPV6_RECVHOPLIMIT (2.6.14) +.\" IPV6_RECVHOPOPTS (2.6.14) +.\" IPV6_RTHDRDSTOPTS (2.6.14) +.\" IPV6_RECVRTHDR (2.6.14) +.\" IPV6_RECVDSTOPTS (2.6.14) +.\" +.\" IPV6_RECVPATHMTU (Linux 2.6.35, flag value added in Linux 2.6.14) +.\" commit 793b14731686595a741d9f47726ad8b9a235385a +.\" Author: Brian Haley <brian.haley@hp.com> +.\" IPV6_PATHMTU (Linux 2.6.35, flag value added in Linux 2.6.14) +.\" commit 793b14731686595a741d9f47726ad8b9a235385a +.\" Author: Brian Haley <brian.haley@hp.com> +.\" IPV6_DONTFRAG (Linux 2.6.35, flag value added in Linux 2.6.14) +.\" commit 793b14731686595a741d9f47726ad8b9a235385a +.\" Author: Brian Haley <brian.haley@hp.com> +.\" commit 4b340ae20d0e2366792abe70f46629e576adaf5e +.\" Author: Brian Haley <brian.haley@hp.com> +.\" +.\" IPV6_RECVTCLASS (Linux 2.6.14) +.\" commit 41a1f8ea4fbfcdc4232f023732584aae2220de31 +.\" Author: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> +.\" Based on patch from David L Stevens <dlstevens@us.ibm.com> +.\" +.\" IPV6_CHECKSUM (Linux 2.2) +.\" IPV6_NEXTHOP (Linux 2.2) +.\" IPV6_JOIN_ANYCAST (Linux 2.4.21 / Linux 2.6) +.\" IPV6_LEAVE_ANYCAST (Linux 2.4.21 / Linux 2.6) +.\" IPV6_FLOWLABEL_MGR (Linux 2.2.7 / Linux 2.4) +.\" IPV6_FLOWINFO_SEND (Linux 2.2.7 / Linux 2.4) +.\" IPV6_IPSEC_POLICY (Linux 2.6) +.\" IPV6_XFRM_POLICY (Linux 2.6) +.\" IPV6_TCLASS (Linux 2.6) +.\" +.\" IPV6_ADDR_PREFERENCES (Linux 2.6.26) +.\" commit 7cbca67c073263c179f605bdbbdc565ab29d801d +.\" Author: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> +.\" IPV6_MINHOPCOUNT (Linux 2.6.35) +.\" commit e802af9cabb011f09b9c19a82faef3dd315f27eb +.\" Author: Stephen Hemminger <shemminger@vyatta.com> +.\" IPV6_ORIGDSTADDR (Linux 2.6.37) +.\" Actually a CMSG rather than a sockopt? +.\" In header file, we have IPV6_RECVORIGDSTADDR == IPV6_ORIGDSTADDR +.\" commit 6c46862280c5f55eda7750391bc65cd7e08c7535 +.\" Author: Balazs Scheidler <bazsi@balabit.hu> +.\" IPV6_RECVORIGDSTADDR (Linux 2.6.37) +.\" commit 6c46862280c5f55eda7750391bc65cd7e08c7535 +.\" Author: Balazs Scheidler <bazsi@balabit.hu> +.\" Support for IPV6_RECVORIGDSTADDR sockopt for UDP sockets +.\" were contributed by Harry Mason. +.\" IPV6_TRANSPARENT (Linux 2.6.37) +.\" commit 6c46862280c5f55eda7750391bc65cd7e08c7535 +.\" Author: Balazs Scheidler <bazsi@balabit.hu> +.\" IPV6_UNICAST_IF (Linux 3.4) +.\" commit c4062dfc425e94290ac427a98d6b4721dd2bc91f +.\" Author: Erich E. Hoover <ehoover@mines.edu> +.\" +.TH ipv6 7 2023-07-30 "Linux man-pages 6.05.01" +.SH NAME +ipv6 \- Linux IPv6 protocol implementation +.SH SYNOPSIS +.nf +.B #include <sys/socket.h> +.B #include <netinet/in.h> +.PP +.IB tcp6_socket " = socket(AF_INET6, SOCK_STREAM, 0);" +.IB raw6_socket " = socket(AF_INET6, SOCK_RAW, " protocol ");" +.IB udp6_socket " = socket(AF_INET6, SOCK_DGRAM, " protocol ");" +.fi +.SH DESCRIPTION +Linux 2.2 optionally implements the Internet Protocol, version 6. +This man page contains a description of the IPv6 basic API as +implemented by the Linux kernel and glibc 2.1. +The interface +is based on the BSD sockets interface; see +.BR socket (7). +.PP +The IPv6 API aims to be mostly compatible with the +IPv4 API (see +.BR ip (7)). +Only differences are described in this man page. +.PP +To bind an +.B AF_INET6 +socket to any process, the local address should be copied from the +.I in6addr_any +variable which has +.I in6_addr +type. +In static initializations, +.B IN6ADDR_ANY_INIT +may also be used, which expands to a constant expression. +Both of them are in network byte order. +.PP +The IPv6 loopback address (::1) is available in the global +.I in6addr_loopback +variable. +For initializations, +.B IN6ADDR_LOOPBACK_INIT +should be used. +.PP +IPv4 connections can be handled with the v6 API by using the +v4-mapped-on-v6 address type; +thus a program needs to support only this API type to +support both protocols. +This is handled transparently by the address +handling functions in the C library. +.PP +IPv4 and IPv6 share the local port space. +When you get an IPv4 connection +or packet to an IPv6 socket, +its source address will be mapped to v6. +.SS Address format +.in +4n +.EX +struct sockaddr_in6 { + sa_family_t sin6_family; /* AF_INET6 */ + in_port_t sin6_port; /* port number */ + uint32_t sin6_flowinfo; /* IPv6 flow information */ + struct in6_addr sin6_addr; /* IPv6 address */ + uint32_t sin6_scope_id; /* Scope ID (new in Linux 2.4) */ +}; +\& +struct in6_addr { + unsigned char s6_addr[16]; /* IPv6 address */ +}; +.EE +.in +.PP +.I sin6_family +is always set to +.BR AF_INET6 ; +.I sin6_port +is the protocol port (see +.I sin_port +in +.BR ip (7)); +.I sin6_flowinfo +is the IPv6 flow identifier; +.I sin6_addr +is the 128-bit IPv6 address. +.I sin6_scope_id +is an ID depending on the scope of the address. +It is new in Linux 2.4. +Linux supports it only for link-local addresses, in that case +.I sin6_scope_id +contains the interface index (see +.BR netdevice (7)) +.PP +IPv6 supports several address types: unicast to address a single +host, multicast to address a group of hosts, +anycast to address the nearest member of a group of hosts +(not implemented in Linux), IPv4-on-IPv6 to +address an IPv4 host, and other reserved address types. +.PP +The address notation for IPv6 is a group of 8 4-digit hexadecimal +numbers, separated with a \[aq]:\[aq]. +\&"::" stands for a string of 0 bits. +Special addresses are ::1 for loopback and ::FFFF:<IPv4 address> +for IPv4-mapped-on-IPv6. +.PP +The port space of IPv6 is shared with IPv4. +.SS Socket options +IPv6 supports some protocol-specific socket options that can be set with +.BR setsockopt (2) +and read with +.BR getsockopt (2). +The socket option level for IPv6 is +.BR IPPROTO_IPV6 . +A boolean integer flag is zero when it is false, otherwise true. +.TP +.B IPV6_ADDRFORM +Turn an +.B AF_INET6 +socket into a socket of a different address family. +Only +.B AF_INET +is currently supported for that. +It is allowed only for IPv6 sockets +that are connected and bound to a v4-mapped-on-v6 address. +The argument is a pointer to an integer containing +.BR AF_INET . +This is useful to pass v4-mapped sockets as file descriptors to +programs that don't know how to deal with the IPv6 API. +.TP +.B IPV6_ADD_MEMBERSHIP, IPV6_DROP_MEMBERSHIP +Control membership in multicast groups. +Argument is a pointer to a +.IR "struct ipv6_mreq" . +.TP +.B IPV6_MTU +.BR getsockopt (): +Retrieve the current known path MTU of the current socket. +Valid only when the socket has been connected. +Returns an integer. +.IP +.BR setsockopt (): +Set the MTU to be used for the socket. +The MTU is limited by the device +MTU or the path MTU when path MTU discovery is enabled. +Argument is a pointer to integer. +.TP +.B IPV6_MTU_DISCOVER +Control path-MTU discovery on the socket. +See +.B IP_MTU_DISCOVER +in +.BR ip (7) +for details. +.TP +.B IPV6_MULTICAST_HOPS +Set the multicast hop limit for the socket. +Argument is a pointer to an +integer. +\-1 in the value means use the route default, otherwise it should be +between 0 and 255. +.TP +.B IPV6_MULTICAST_IF +Set the device for outgoing multicast packets on the socket. +This is allowed only for +.B SOCK_DGRAM +and +.B SOCK_RAW +socket. +The argument is a pointer to an interface index (see +.BR netdevice (7)) +in an integer. +.TP +.B IPV6_MULTICAST_LOOP +Control whether the socket sees multicast packets that it has send itself. +Argument is a pointer to boolean. +.TP +.BR IPV6_RECVPKTINFO " (since Linux 2.6.14)" +Set delivery of the +.B IPV6_PKTINFO +control message on incoming datagrams. +Such control messages contain a +.IR "struct in6_pktinfo" , +as per RFC 3542. +Allowed only for +.B SOCK_DGRAM +or +.B SOCK_RAW +sockets. +Argument is a pointer to a boolean value in an integer. +.TP +.B \%IPV6_RTHDR, \%IPV6_AUTHHDR, \%IPV6_DSTOPTS, \%IPV6_HOPOPTS, \ +\%IPV6_FLOWINFO, \%IPV6_HOPLIMIT +Set delivery of control messages for incoming datagrams containing +extension headers from the received packet. +.B IPV6_RTHDR +delivers the routing header, +.B IPV6_AUTHHDR +delivers the authentication header, +.B IPV6_DSTOPTS +delivers the destination options, +.B IPV6_HOPOPTS +delivers the hop options, +.B IPV6_FLOWINFO +delivers an integer containing the flow ID, +.B IPV6_HOPLIMIT +delivers an integer containing the hop count of the packet. +The control messages have the same type as the socket option. +All these header options can also be set for outgoing packets +by putting the appropriate control message into the control buffer of +.BR sendmsg (2). +Allowed only for +.B SOCK_DGRAM +or +.B SOCK_RAW +sockets. +Argument is a pointer to a boolean value. +.TP +.B IPV6_RECVERR +Control receiving of asynchronous error options. +See +.B IP_RECVERR +in +.BR ip (7) +for details. +Argument is a pointer to boolean. +.TP +.B IPV6_ROUTER_ALERT +Pass forwarded packets containing a router alert hop-by-hop option to +this socket. +Allowed only for +.B SOCK_RAW +sockets. +The tapped packets are not forwarded by the kernel, it is the +user's responsibility to send them out again. +Argument is a pointer to an integer. +A positive integer indicates a router alert option value to intercept. +Packets carrying a router alert option with a value field containing +this integer will be delivered to the socket. +A negative integer disables delivery of packets with router alert options +to this socket. +.TP +.B IPV6_UNICAST_HOPS +Set the unicast hop limit for the socket. +Argument is a pointer to an integer. +\-1 in the value means use the route default, +otherwise it should be between 0 and 255. +.TP +.BR IPV6_V6ONLY " (since Linux 2.4.21 and 2.6)" +.\" See RFC 3493 +If this flag is set to true (nonzero), then the socket is restricted +to sending and receiving IPv6 packets only. +In this case, an IPv4 and an IPv6 application can bind +to a single port at the same time. +.IP +If this flag is set to false (zero), +then the socket can be used to send and receive packets +to and from an IPv6 address or an IPv4-mapped IPv6 address. +.IP +The argument is a pointer to a boolean value in an integer. +.IP +The default value for this flag is defined by the contents of the file +.IR /proc/sys/net/ipv6/bindv6only . +The default value for that file is 0 (false). +.\" FLOWLABEL_MGR, FLOWINFO_SEND +.SH ERRORS +.TP +.B ENODEV +The user tried to +.BR bind (2) +to a link-local IPv6 address, but the +.I sin6_scope_id +in the supplied +.I sockaddr_in6 +structure is not a valid +interface index. +.SH VERSIONS +Linux 2.4 will break binary compatibility for the +.I sockaddr_in6 +for 64-bit +hosts by changing the alignment of +.I in6_addr +and adding an additional +.I sin6_scope_id +field. +The kernel interfaces stay compatible, but a program including +.I sockaddr_in6 +or +.I in6_addr +into other structures may not be. +This is not +a problem for 32-bit hosts like i386. +.PP +The +.I sin6_flowinfo +field is new in Linux 2.4. +It is transparently passed/read by the kernel +when the passed address length contains it. +Some programs that pass a longer address buffer and then +check the outgoing address length may break. +.SH NOTES +The +.I sockaddr_in6 +structure is bigger than the generic +.IR sockaddr . +Programs that assume that all address types can be stored safely in a +.I struct sockaddr +need to be changed to use +.I struct sockaddr_storage +for that instead. +.PP +.BR SOL_IP , +.BR SOL_IPV6 , +.BR SOL_ICMPV6 , +and other +.B SOL_* +socket options are nonportable variants of +.BR IPPROTO_* . +See also +.BR ip (7). +.SH BUGS +The IPv6 extended API as in RFC\ 2292 is currently only partly +implemented; +although the 2.2 kernel has near complete support for receiving options, +the macros for generating IPv6 options are missing in glibc 2.1. +.PP +IPSec support for EH and AH headers is missing. +.PP +Flow label management is not complete and not documented here. +.PP +This man page is not complete. +.SH SEE ALSO +.BR cmsg (3), +.BR ip (7) +.PP +RFC\ 2553: IPv6 BASIC API; +Linux tries to be compliant to this. +RFC\ 2460: IPv6 specification. |