Index: head/lib/libc/net/getaddrinfo.3
===================================================================
--- head/lib/libc/net/getaddrinfo.3	(revision 343966)
+++ head/lib/libc/net/getaddrinfo.3	(revision 343967)
@@ -1,520 +1,520 @@
 .\"	$KAME: getaddrinfo.3,v 1.36 2005/01/05 03:23:05 itojun Exp $
 .\"	$OpenBSD: getaddrinfo.3,v 1.35 2004/12/21 03:40:31 jaredy Exp $
 .\"
 .\" Copyright (C) 2004  Internet Systems Consortium, Inc. ("ISC")
 .\" Copyright (C) 2000, 2001  Internet Software Consortium.
 .\"
 .\" Permission to use, copy, modify, and distribute this software for any
 .\" purpose with or without fee is hereby granted, provided that the above
 .\" copyright notice and this permission notice appear in all copies.
 .\"
 .\" THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
 .\" REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 .\" AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
 .\" INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
 .\" LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
 .\" OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 .\" PERFORMANCE OF THIS SOFTWARE.
 .\"
 .\" $FreeBSD$
 .\"
-.Dd September 13, 2017
+.Dd February 10, 2019
 .Dt GETADDRINFO 3
 .Os
 .Sh NAME
 .Nm getaddrinfo ,
 .Nm freeaddrinfo
 .Nd socket address structure to host and service name
 .Sh SYNOPSIS
 .In sys/types.h
 .In sys/socket.h
 .In netdb.h
 .Ft int
 .Fo getaddrinfo
 .Fa "const char *hostname" "const char *servname"
 .Fa "const struct addrinfo *hints" "struct addrinfo **res"
 .Fc
 .Ft void
 .Fn freeaddrinfo "struct addrinfo *ai"
 .Sh DESCRIPTION
 The
 .Fn getaddrinfo
 function is used to get a list of
 addresses and port numbers for host
 .Fa hostname
 and service
 .Fa servname .
 It is a replacement for and provides more flexibility than the
 .Xr gethostbyname 3
 and
 .Xr getservbyname 3
 functions.
 .Pp
 The
 .Fa hostname
 and
 .Fa servname
 arguments are either pointers to NUL-terminated strings or the null pointer.
 An acceptable value for
 .Fa hostname
 is either a valid host name or a numeric host address string consisting
 of a dotted decimal IPv4 address,
 an IPv6 address,
 or a UNIX-domain address.
 The
 .Fa servname
 is either a decimal port number or a service name listed in
 .Xr services 5 .
 At least one of
 .Fa hostname
 and
 .Fa servname
 must be non-null.
 .Pp
 .Fa hints
 is an optional pointer to a
 .Li struct addrinfo ,
 as defined by
 .Aq Pa netdb.h :
 .Bd -literal
 struct addrinfo {
-	int ai_flags;		/* input flags */
-	int ai_family;		/* address family for socket */
-	int ai_socktype;	/* socket type */
-	int ai_protocol;	/* protocol for socket */
-	socklen_t ai_addrlen;	/* length of socket-address */
-	struct sockaddr *ai_addr; /* socket-address for socket */
-	char *ai_canonname;	/* canonical name for service location */
-	struct addrinfo *ai_next; /* pointer to next in list */
+        int     ai_flags;       /* AI_PASSIVE, AI_CANONNAME, .. */
+        int     ai_family;      /* AF_xxx */
+        int     ai_socktype;    /* SOCK_xxx */
+        int     ai_protocol;    /* 0 or IPPROTO_xxx for IPv4 and IPv6 */
+        socklen_t ai_addrlen;   /* length of ai_addr */
+        char    *ai_canonname;  /* canonical name for hostname */
+        struct  sockaddr *ai_addr;      /* binary address */
+        struct  addrinfo *ai_next;      /* next structure in linked list */
 };
 .Ed
 .Pp
 This structure can be used to provide hints concerning the type of socket
 that the caller supports or wishes to use.
 The caller can supply the following structure elements in
 .Fa hints :
 .Bl -tag -width "ai_socktypeXX"
 .It Fa ai_family
 The address family that should be used.
 When
 .Fa ai_family
 is set to
 .Dv AF_UNSPEC ,
 it means the caller will accept any address family supported by the
 operating system.
 .It Fa ai_socktype
 Denotes the type of socket that is wanted:
 .Dv SOCK_STREAM ,
 .Dv SOCK_DGRAM ,
 .Dv SOCK_SEQPACKET ,
 or
 .Dv SOCK_RAW .
 When
 .Fa ai_socktype
 is zero the caller will accept any socket type.
 .It Fa ai_protocol
 Indicates which transport protocol is desired,
 .Dv IPPROTO_UDP ,
 .Dv IPPROTO_TCP ,
 .Dv IPPROTO_SCTP ,
 or
 .Dv IPPROTO_UDPLITE .
 If
 .Fa ai_protocol
 is zero the caller will accept any protocol.
 .It Fa ai_flags
 The
 .Fa ai_flags
 field to which the
 .Fa hints
 parameter points shall be set to zero
 or be the bitwise-inclusive OR of one or more of the values
 .Dv AI_ADDRCONFIG ,
 .Dv AI_ALL ,
 .Dv AI_CANONNAME ,
 .Dv AI_NUMERICHOST ,
 .Dv AI_NUMERICSERV ,
 .Dv AI_PASSIVE
 and
 .Dv AI_V4MAPPED .
 For a UNIX-domain address,
 .Fa ai_flags
 is ignored.
 .Bl -tag -width "AI_CANONNAMEXX"
 .It Dv AI_ADDRCONFIG
 If the
 .Dv AI_ADDRCONFIG
 bit is set, IPv4 addresses shall be returned only if
 an IPv4 address is configured on the local system,
 and IPv6 addresses shall be returned only if
 an IPv6 address is configured on the local system.
 .It Dv AI_ALL
 If the
 .Dv AI_ALL
 flag is used with the
 .Dv AI_V4MAPPED
 flag, then
 .Fn getaddrinfo
 shall return all matching IPv6 and IPv4 addresses.
 .Pp
 For example, when using the DNS, queries are made for both AAAA records and A records, and
 .Fn getaddrinfo
 returns the combined results of both queries.
 Any IPv4 addresses found are returned as IPv4-mapped IPv6 addresses.
 .Pp
 The
 .Dv AI_ALL
 flag without the
 .Dv AI_V4MAPPED
 flag is ignored.
 .It Dv AI_CANONNAME
 If the
 .Dv AI_CANONNAME
 bit is set, a successful call to
 .Fn getaddrinfo
 will return a NUL-terminated string containing the canonical name
 of the specified hostname in the
 .Fa ai_canonname
 element of the first
 .Li addrinfo
 structure returned.
 .It Dv AI_NUMERICHOST
 If the
 .Dv AI_NUMERICHOST
 bit is set, it indicates that
 .Fa hostname
 should be treated as a numeric string defining an IPv4 or IPv6 address
 and no name resolution should be attempted.
 .It Dv AI_NUMERICSERV
 If the
 .Dv AI_NUMERICSERV
 bit is set,
 then a non-null
 .Fa servname
 string supplied shall be a numeric port string.
 Otherwise, an
 .Dv EAI_NONAME
 error shall be returned.
 This bit shall prevent any type of name resolution service
 (for example, NIS+) from being invoked.
 .It Dv AI_PASSIVE
 If the
 .Dv AI_PASSIVE
 bit is set it indicates that the returned socket address structure
 is intended for use in a call to
 .Xr bind 2 .
 In this case, if the
 .Fa hostname
 argument is the null pointer, then the IP address portion of the
 socket address structure will be set to
 .Dv INADDR_ANY
 for an IPv4 address or
 .Dv IN6ADDR_ANY_INIT
 for an IPv6 address.
 .Pp
 If the
 .Dv AI_PASSIVE
 bit is not set, the returned socket address structure will be ready
 for use in a call to
 .Xr connect 2
 for a connection-oriented protocol or
 .Xr connect 2 ,
 .Xr sendto 2 ,
 or
 .Xr sendmsg 2
 if a connectionless protocol was chosen.
 The
 .Tn IP
 address portion of the socket address structure will be set to the
 loopback address if
 .Fa hostname
 is the null pointer and
 .Dv AI_PASSIVE
 is not set.
 .It Dv AI_V4MAPPED
 If the
 .Dv AI_V4MAPPED
 flag is specified along with an ai_family of
 .Dv AF_INET6 ,
 then
 .Fn getaddrinfo
 shall return IPv4-mapped IPv6 addresses on finding no matching IPv6 addresses (
 .Fa ai_addrlen
 shall be 16).
 .Pp
 For example, when using the DNS, if no AAAA records are found then a query is made for A records and any found are returned as IPv4-mapped IPv6 addresses.
 .Pp
 The
 .Dv AI_V4MAPPED
 flag shall be ignored unless
 .Fa ai_family
 equals
 .Dv AF_INET6 .
 .El
 .El
 .Pp
 All other elements of the
 .Li addrinfo
 structure passed via
 .Fa hints
 must be zero or the null pointer.
 .Pp
 If
 .Fa hints
 is the null pointer,
 .Fn getaddrinfo
 behaves as if the caller provided a
 .Li struct addrinfo
 with
 .Fa ai_family
 set to
 .Dv AF_UNSPEC
 and all other elements set to zero or
 .Dv NULL .
 .Pp
 After a successful call to
 .Fn getaddrinfo ,
 .Fa *res
 is a pointer to a linked list of one or more
 .Li addrinfo
 structures.
 The list can be traversed by following the
 .Fa ai_next
 pointer in each
 .Li addrinfo
 structure until a null pointer is encountered.
 Each returned
 .Li addrinfo
 structure contains three members that are suitable for a call to
 .Xr socket 2 :
 .Fa ai_family ,
 .Fa ai_socktype ,
 and
 .Fa ai_protocol .
 For each
 .Li addrinfo
 structure in the list, the
 .Fa ai_addr
 member points to a filled-in socket address structure of length
 .Fa ai_addrlen .
 .Pp
 This implementation of
 .Fn getaddrinfo
 allows numeric IPv6 address notation with scope identifier,
 as documented in chapter 11 of RFC 4007.
 By appending the percent character and scope identifier to addresses,
 one can fill the
 .Li sin6_scope_id
 field for addresses.
 This would make management of scoped addresses easier
 and allows cut-and-paste input of scoped addresses.
 .Pp
 At this moment the code supports only link-local addresses with the format.
 The scope identifier is hardcoded to the name of the hardware interface
 associated
 with the link
 .Po
 such as
 .Li ne0
 .Pc .
 An example is
 .Dq Li fe80::1%ne0 ,
 which means
 .Do
 .Li fe80::1
 on the link associated with the
 .Li ne0
 interface
 .Dc .
 .Pp
 The current implementation assumes a one-to-one relationship between
 the interface and link, which is not necessarily true from the specification.
 .Pp
 All of the information returned by
 .Fn getaddrinfo
 is dynamically allocated: the
 .Li addrinfo
 structures themselves as well as the socket address structures and
 the canonical host name strings included in the
 .Li addrinfo
 structures.
 .Pp
 Memory allocated for the dynamically allocated structures created by
 a successful call to
 .Fn getaddrinfo
 is released by the
 .Fn freeaddrinfo
 function.
 The
 .Fa ai
 pointer should be a
 .Li addrinfo
 structure created by a call to
 .Fn getaddrinfo .
 .Sh IMPLEMENTATION NOTES
 The behavior of
 .Li freeadrinfo(NULL)
 is left unspecified by both
 .St -susv4
 and
 .Dv "RFC 3493" .
 The current implementation ignores a
 .Dv NULL
 argument for compatibility with programs that rely on the implementation
 details of other operating systems.
 .Sh RETURN VALUES
 .Fn getaddrinfo
 returns zero on success or one of the error codes listed in
 .Xr gai_strerror 3
 if an error occurs.
 .Sh EXAMPLES
 The following code tries to connect to
 .Dq Li www.kame.net
 service
 .Dq Li http
 via a stream socket.
 It loops through all the addresses available, regardless of address family.
 If the destination resolves to an IPv4 address, it will use an
 .Dv AF_INET
 socket.
 Similarly, if it resolves to IPv6, an
 .Dv AF_INET6
 socket is used.
 Observe that there is no hardcoded reference to a particular address family.
 The code works even if
 .Fn getaddrinfo
 returns addresses that are not IPv4/v6.
 .Bd -literal -offset indent
 struct addrinfo hints, *res, *res0;
 int error;
 int s;
 const char *cause = NULL;
 
 memset(&hints, 0, sizeof(hints));
 hints.ai_family = AF_UNSPEC;
 hints.ai_socktype = SOCK_STREAM;
 error = getaddrinfo("www.kame.net", "http", &hints, &res0);
 if (error) {
 	errx(1, "%s", gai_strerror(error));
 	/* NOTREACHED */
 }
 s = -1;
 for (res = res0; res; res = res->ai_next) {
 	s = socket(res->ai_family, res->ai_socktype,
 	    res->ai_protocol);
 	if (s < 0) {
 		cause = "socket";
 		continue;
 	}
 
 	if (connect(s, res->ai_addr, res->ai_addrlen) < 0) {
 		cause = "connect";
 		close(s);
 		s = -1;
 		continue;
 	}
 
 	break;	/* okay we got one */
 }
 if (s < 0) {
 	err(1, "%s", cause);
 	/* NOTREACHED */
 }
 freeaddrinfo(res0);
 .Ed
 .Pp
 The following example tries to open a wildcard listening socket onto service
 .Dq Li http ,
 for all the address families available.
 .Bd -literal -offset indent
 struct addrinfo hints, *res, *res0;
 int error;
 int s[MAXSOCK];
 int nsock;
 const char *cause = NULL;
 
 memset(&hints, 0, sizeof(hints));
 hints.ai_family = AF_UNSPEC;
 hints.ai_socktype = SOCK_STREAM;
 hints.ai_flags = AI_PASSIVE;
 error = getaddrinfo(NULL, "http", &hints, &res0);
 if (error) {
 	errx(1, "%s", gai_strerror(error));
 	/* NOTREACHED */
 }
 nsock = 0;
 for (res = res0; res && nsock < MAXSOCK; res = res->ai_next) {
 	s[nsock] = socket(res->ai_family, res->ai_socktype,
 	    res->ai_protocol);
 	if (s[nsock] < 0) {
 		cause = "socket";
 		continue;
 	}
 
 	if (bind(s[nsock], res->ai_addr, res->ai_addrlen) < 0) {
 		cause = "bind";
 		close(s[nsock]);
 		continue;
 	}
 	(void) listen(s[nsock], 5);
 
 	nsock++;
 }
 if (nsock == 0) {
 	err(1, "%s", cause);
 	/* NOTREACHED */
 }
 freeaddrinfo(res0);
 .Ed
 .Sh SEE ALSO
 .Xr bind 2 ,
 .Xr connect 2 ,
 .Xr send 2 ,
 .Xr socket 2 ,
 .Xr gai_strerror 3 ,
 .Xr gethostbyname 3 ,
 .Xr getnameinfo 3 ,
 .Xr getservbyname 3 ,
 .Xr resolver 3 ,
 .Xr inet 4 ,
 .Xr inet6 4 ,
 .Xr unix 4 ,
 .Xr hosts 5 ,
 .Xr resolv.conf 5 ,
 .Xr services 5 ,
 .Xr hostname 7 ,
 .Xr named 8
 .Rs
 .%A R. Gilligan
 .%A S. Thomson
 .%A J. Bound
 .%A J. McCann
 .%A W. Stevens
 .%T Basic Socket Interface Extensions for IPv6
 .%R RFC 3493
 .%D February 2003
 .Re
 .Rs
 .%A S. Deering
 .%A B. Haberman
 .%A T. Jinmei
 .%A E. Nordmark
 .%A B. Zill
 .%T "IPv6 Scoped Address Architecture"
 .%R RFC 4007
 .%D March 2005
 .Re
 .Rs
 .%A Craig Metz
 .%T Protocol Independence Using the Sockets API
 .%B "Proceedings of the freenix track: 2000 USENIX annual technical conference"
 .%D June 2000
 .Re
 .Sh STANDARDS
 The
 .Fn getaddrinfo
 function is defined by the
 .St -p1003.1-2004
 specification and documented in
 .Dv "RFC 3493" ,
 .Dq Basic Socket Interface Extensions for IPv6 .