openssl/doc/crypto/BIO_ADDR.pod
Richard Levitte 28a0841bf5 Refactoring BIO: add wrappers around sockaddr et al
Because different platforms have different levels of support for IPv6,
different kinds of sockaddr variants, and some have getaddrinfo et al
while others don't, we could end up with a mess if ifdefs, duplicate
code and other maintainance nightmares.

Instead, we're introducing wrappers around the common form for socket
communication:
BIO_ADDR, closely related to struct sockaddr and some of its variants.
BIO_ADDRINFO, closely related to struct addrinfo.

With that comes support routines, both convenient creators and
accessors, plus a few utility functions:

BIO_parse_hostserv, takes a string of the form host:service and
splits it into host and service.  It checks for * in both parts, and
converts any [ipv6-address] syntax to ust the IPv6 address.

BIO_lookup, looks up information on a host.

All routines handle IPv4 (AF_INET) and IPv6 (AF_INET6) addresses, and
there is support for local sockets (AF_UNIX) as well.

Reviewed-by: Kurt Roeckx <kurt@openssl.org>
2016-02-03 19:37:07 +01:00

109 lines
4.3 KiB
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=pod
=head1 NAME
BIO_ADDR, BIO_ADDR_new, BIO_ADDR_free, BIO_ADDR_rawmake,
BIO_ADDR_family, BIO_ADDR_rawaddress, BIO_ADDR_rawport,
BIO_ADDR_hostname_string, BIO_ADDR_service_string,
BIO_ADDR_path_string - BIO_ADDR routines
=head1 SYNOPSIS
#include <sys/types.h>
#include <openssl/bio.h>
typedef union bio_addr_st BIO_ADDR;
BIO_ADDR *BIO_ADDR_new(void);
void BIO_ADDR_free(BIO_ADDR *);
int BIO_ADDR_rawmake(BIO_ADDR *ap, int family,
const void *where, size_t wherelen, unsigned short port);
int BIO_ADDR_family(const BIO_ADDR *ap);
int BIO_ADDR_rawaddress(const BIO_ADDR *ap, void *p, size_t *l);
unsigned short BIO_ADDR_rawport(const BIO_ADDR *ap);
char *BIO_ADDR_hostname_string(const BIO_ADDR *ap, int numeric);
char *BIO_ADDR_service_string(const BIO_ADDR *ap, int numeric);
char *BIO_ADDR_path_string(const BIO_ADDR *ap);
=head1 DESCRIPTION
The B<BIO_ADDR> type is a wrapper around all types of socket
addresses that OpenSSL deals with, currently transparently
supporting AF_INET, AF_INET6 and AF_UNIX according to what's
available on the platform at hand.
BIO_ADDR_new() creates a new unfilled B<BIO_ADDR>, to be used
with routines that will fill it with information, such as
BIO_accept_ex().
BIO_ADDR_free() frees a B<BIO_ADDR> created with BIO_ADDR_new().
BIO_ADDR_rawmake() takes a protocol B<family>, an byte array of
size B<wherelen> with an address in network byte order pointed at
by B<where> and a port number in network byte order in B<port> (except
for the B<AF_UNIX> protocol family, where B<port> is meaningless and
therefore ignored) and populates the given B<BIO_ADDR> with them.
In case this creates a B<AF_UNIX> B<BIO_ADDR>, B<wherelen> is expected
to be the length of the path string (not including the terminating
NUL, such as the result of a call to strlen()).
I<Read on about the addresses in L</RAW ADDRESSES> below>.
BIO_ADDR_family() returns the protocol family of the given
B<BIO_ADDR>. The possible non-error results are one of the
constants AF_INET, AF_INET6 and AF_UNIX.
BIO_ADDR_rawaddress() will write the raw address of the given
B<BIO_ADDR> in the area pointed at by B<p> if B<p> is non-NULL,
and will set B<*l> to be the amount of bytes the raw address
takes up if B<l> is non-NULL.
A technique to only find out the size of the address is a call
with B<p> set to B<NULL>. The raw address will be in network byte
order, most significant byte first.
In case this is a B<AF_UNIX> B<BIO_ADDR>, B<l> gets the length of the
path string (not including the terminating NUL, such as the result of
a call to strlen()).
I<Read on about the addresses in L</RAW ADDRESSES> below>.
BIO_ADDR_rawport() returns the raw port of the given B<BIO_ADDR>.
The raw port will be in network byte order.
BIO_ADDR_hostname_string() returns a character string with the
hostname of the given B<BIO_ADDR>. If B<numeric> is 1, the string
will contain the numerical form of the address. This only works for
B<BIO_ADDR> of the protocol families AF_INET and AF_INET6. The
returned string has been allocated on the heap and must be freed
with OPENSSL_free().
BIO_ADDR_service_string() returns a character string with the
service name of the port of the given B<BIO_ADDR>. If B<numeric>
is 1, the string will contain the port number. This only works
for B<BIO_ADDR> of the protocol families AF_INET and AF_INET6. The
returned string has been allocated on the heap and must be freed
with OPENSSL_free().
BIO_ADDR_path_string() returns a character string with the path
of the given B<BIO_ADDR>. This only works for B<BIO_ADDR> of the
protocol family AF_UNIX. The returned string has been allocated
on the heap and must be freed with OPENSSL_free().
=head1 RAW ADDRESSES
Both BIO_ADDR_rawmake() and BIO_ADDR_rawaddress() take a pointer to a
network byte order address of a specific site. Internally, those are
treated as a pointer to B<struct in_addr> (for B<AF_INET>), B<struct
in6_addr> (for B<AF_INET6>) or B<char *> (for B<AF_UNIX>), all
depending on the protocol family the address is for.
=head1 RETURN VALUES
The string producing functions BIO_ADDR_hostname_string(),
BIO_ADDR_service_string() and BIO_ADDR_path_string() will
return B<NULL> on error and leave an error indication on the
OpenSSL error stack.
All other functions described here return 0 or B<NULL> when the
information they should return isn't available.
=head1 SEE ALSO
L<BIO_connect(3)>, L<BIO_s_connect(3)>