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Diffstat (limited to 'man3/inet_pton.3')
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diff --git a/man3/inet_pton.3 b/man3/inet_pton.3 new file mode 100644 index 0000000..420a642 --- /dev/null +++ b/man3/inet_pton.3 @@ -0,0 +1,224 @@ +'\" t +.\" Copyright 2000 Sam Varshavchik <mrsam@courier-mta.com> +.\" and Copyright (c) 2008 Michael Kerrisk <mtk.manpages@gmail.com> +.\" +.\" SPDX-License-Identifier: Linux-man-pages-copyleft +.\" +.\" References: RFC 2553 +.TH inet_pton 3 2023-07-20 "Linux man-pages 6.05.01" +.SH NAME +inet_pton \- convert IPv4 and IPv6 addresses from text to binary form +.SH LIBRARY +Standard C library +.RI ( libc ", " \-lc ) +.SH SYNOPSIS +.nf +.B #include <arpa/inet.h> +.PP +.BI "int inet_pton(int " af ", const char *restrict " src \ +", void *restrict " dst ); +.fi +.SH DESCRIPTION +This function converts the character string +.I src +into a network address structure in the +.I af +address family, then +copies +the network address structure to +.IR dst . +The +.I af +argument must be either +.B AF_INET +or +.BR AF_INET6 . +.I dst +is written in network byte order. +.PP +The following address families are currently supported: +.TP +.B AF_INET +.I src +points to a character string containing an IPv4 network address in +dotted-decimal format, "\fIddd.ddd.ddd.ddd\fP", where +.I ddd +is a decimal number of up to three digits in the range 0 to 255. +The address is converted to a +.I struct in_addr +and copied to +.IR dst , +which must be +.I sizeof(struct in_addr) +(4) bytes (32 bits) long. +.TP +.B AF_INET6 +.I src +points to a character string containing an IPv6 network address. +The address is converted to a +.I struct in6_addr +and copied to +.IR dst , +which must be +.I sizeof(struct in6_addr) +(16) bytes (128 bits) long. +The allowed formats for IPv6 addresses follow these rules: +.RS +.IP \[bu] 3 +The preferred format is +.IR x:x:x:x:x:x:x:x . +This form consists of eight hexadecimal numbers, +each of which expresses a 16-bit value (i.e., each +.I x +can be up to 4 hex digits). +.IP \[bu] +A series of contiguous zero values in the preferred format +can be abbreviated to +.IR :: . +Only one instance of +.I :: +can occur in an address. +For example, the loopback address +.I 0:0:0:0:0:0:0:1 +can be abbreviated as +.IR ::1 . +The wildcard address, consisting of all zeros, can be written as +.IR :: . +.IP \[bu] +An alternate format is useful for expressing IPv4-mapped IPv6 addresses. +This form is written as +.IR x:x:x:x:x:x:d.d.d.d , +where the six leading +.IR x s +are hexadecimal values that define the six most-significant +16-bit pieces of the address (i.e., 96 bits), and the +.IR d s +express a value in dotted-decimal notation that +defines the least significant 32 bits of the address. +An example of such an address is +.IR ::FFFF:204.152.189.116 . +.RE +.IP +See RFC 2373 for further details on the representation of IPv6 addresses. +.SH RETURN VALUE +.BR inet_pton () +returns 1 on success (network address was successfully converted). +0 is returned if +.I src +does not contain a character string representing a valid network +address in the specified address family. +If +.I af +does not contain a valid address family, \-1 is returned and +.I errno +is set to +.BR EAFNOSUPPORT . +.SH ATTRIBUTES +For an explanation of the terms used in this section, see +.BR attributes (7). +.TS +allbox; +lbx lb lb +l l l. +Interface Attribute Value +T{ +.na +.nh +.BR inet_pton () +T} Thread safety MT-Safe locale +.TE +.sp 1 +.SH VERSIONS +Unlike +.BR inet_aton (3) +and +.BR inet_addr (3), +.BR inet_pton () +supports IPv6 addresses. +On the other hand, +.BR inet_pton () +accepts only IPv4 addresses in dotted-decimal notation, whereas +.BR inet_aton (3) +and +.BR inet_addr (3) +allow the more general numbers-and-dots notation (hexadecimal +and octal number formats, and formats that don't require all +four bytes to be explicitly written). +For an interface that handles both IPv6 addresses, and IPv4 +addresses in numbers-and-dots notation, see +.BR getaddrinfo (3). +.SH STANDARDS +POSIX.1-2008. +.SH HISTORY +POSIX.1-2001. +.SH BUGS +.B AF_INET6 +does not recognize IPv4 addresses. +An explicit IPv4-mapped IPv6 address must be supplied in +.I src +instead. +.SH EXAMPLES +The program below demonstrates the use of +.BR inet_pton () +and +.BR inet_ntop (3). +Here are some example runs: +.PP +.in +4n +.EX +.RB "$" " ./a.out i6 0:0:0:0:0:0:0:0" +:: +.RB "$" " ./a.out i6 1:0:0:0:0:0:0:8" +1::8 +.RB "$" " ./a.out i6 0:0:0:0:0:FFFF:204.152.189.116" +::ffff:204.152.189.116 +.EE +.in +.SS Program source +\& +.\" SRC BEGIN (inet_pton.c) +.EX +#include <arpa/inet.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +\& +int +main(int argc, char *argv[]) +{ + unsigned char buf[sizeof(struct in6_addr)]; + int domain, s; + char str[INET6_ADDRSTRLEN]; +\& + if (argc != 3) { + fprintf(stderr, "Usage: %s {i4|i6|<num>} string\en", argv[0]); + exit(EXIT_FAILURE); + } +\& + domain = (strcmp(argv[1], "i4") == 0) ? AF_INET : + (strcmp(argv[1], "i6") == 0) ? AF_INET6 : atoi(argv[1]); +\& + s = inet_pton(domain, argv[2], buf); + if (s <= 0) { + if (s == 0) + fprintf(stderr, "Not in presentation format"); + else + perror("inet_pton"); + exit(EXIT_FAILURE); + } +\& + if (inet_ntop(domain, buf, str, INET6_ADDRSTRLEN) == NULL) { + perror("inet_ntop"); + exit(EXIT_FAILURE); + } +\& + printf("%s\en", str); +\& + exit(EXIT_SUCCESS); +} +.EE +.\" SRC END +.SH SEE ALSO +.BR getaddrinfo (3), +.BR inet (3), +.BR inet_ntop (3) |