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Document Next Protocol Negotiation APIs

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Add callback function prototypes, fix description

Reviewed-by: Kurt Roeckx <kurt@openssl.org>
Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3084)
This commit is contained in:
Rich Salz 2017-04-19 12:38:27 -04:00
parent 93d0298665
commit 87b81496fe
1 changed files with 60 additions and 5 deletions
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65
doc/man3/SSL_CTX_set_alpn_select_cb.pod
View file

@ -3,8 +3,9 @@
=head1 NAME
SSL_CTX_set_alpn_protos, SSL_set_alpn_protos, SSL_CTX_set_alpn_select_cb,
SSL_select_next_proto, SSL_get0_alpn_selected - handle application layer
protocol negotiation (ALPN)
SSL_CTX_set_next_proto_select_cb, SSL_CTX_set_next_protos_advertised_cb,
SSL_select_next_proto, SSL_get0_alpn_selected, SSL_get0_next_proto_negotiated
- handle application layer protocol negotiation (ALPN)
=head1 SYNOPSIS
@ -21,13 +22,30 @@ protocol negotiation (ALPN)
const unsigned char *in,
unsigned int inlen,
void *arg), void *arg);
void SSL_get0_alpn_selected(const SSL *ssl, const unsigned char **data,
unsigned int *len);
void SSL_CTX_set_next_protos_advertised_cb(SSL_CTX *ctx,
int (*cb)(SSL *ssl,
const unsigned char **out,
unsigned int *outlen,
void *arg),
void *arg);
void SSL_CTX_set_next_proto_select_cb(SSL_CTX *ctx,
int (*cb)(SSL *s,
unsigned char **out,
unsigned char *outlen,
const unsigned char *in,
unsigned int inlen,
void *arg),
void *arg);
int SSL_select_next_proto(unsigned char **out, unsigned char *outlen,
const unsigned char *server,
unsigned int server_len,
const unsigned char *client,
unsigned int client_len)
void SSL_get0_alpn_selected(const SSL *ssl, const unsigned char **data,
unsigned int *len);
void SSL_get0_next_proto_negotiated(const SSL *s, const unsigned char **data,
unsigned *len);
=head1 DESCRIPTION
@ -59,10 +77,40 @@ B<client>, so it should be copied immediately. If no match is found, the first
item in B<client>, B<client_len> is returned in B<out>, B<outlen>. This
function can also be used in the NPN callback.
SSL_CTX_set_next_proto_select_cb() sets a callback B<cb> that is called when a
client needs to select a protocol from the server's provided list, and a
user-defined pointer argument B<arg> which will be passed to this callback.
For the callback itself, B<out>
must be set to point to the selected protocol (which may be within B<in>).
The length of the protocol name must be written into B<outlen>. The
server's advertised protocols are provided in B<in> and B<inlen>. The
callback can assume that B<in> is syntactically valid. The client must
select a protocol. It is fatal to the connection if this callback returns
a value other than B<SSL_TLSEXT_ERR_OK>. The B<arg> parameter is the pointer
set via SSL_CTX_set_next_proto_select_cb().
SSL_CTX_set_next_protos_advertised_cb() sets a callback B<cb> that is called
when a TLS server needs a list of supported protocols for Next Protocol
Negotiation. The returned list must be in protocol-list format, described
below. The list is
returned by setting B<out> to point to it and B<outlen> to its length. This
memory will not be modified, but the B<SSL> does keep a
reference to it. The callback should return B<SSL_TLSEXT_ERR_OK> if it
wishes to advertise. Otherwise, no such extension will be included in the
ServerHello.
SSL_get0_alpn_selected() returns a pointer to the selected protocol in B<data>
with length B<len>. It is not NUL-terminated. B<data> is set to NULL and B<len>
is set to 0 if no protocol has been selected. B<data> must not be freed.
SSL_get0_next_proto_negotiated() sets B<data> and B<len> to point to the
client's requested protocol for this connection. If the client did not
request any protocol or NPN is not enabled, then B<data> is set to NULL and
B<len> to 0. Note that
the client can request any protocol it chooses. The value returned from
this function need not be a member of the list of supported protocols
provided by the callback.
=head1 NOTES
The protocol-lists must be in wire-format, which is defined as a vector of
@ -125,6 +173,13 @@ this connection.
=back
The callback set using SSL_CTX_set_next_proto_select_cb() should return
B<SSL_TLSEXT_ERR_OK> if successful. Any other value is fatal to the connection.
The callback set using SSL_CTX_set_next_protos_advertised_cb() should return
B<SSL_TLSEXT_ERR_OK> if it wishes to advertise. Otherwise, no such extension
will be included in the ServerHello.
=head1 SEE ALSO
L<ssl(7)>, L<SSL_CTX_set_tlsext_servername_callback(3)>,
@ -132,7 +187,7 @@ L<SSL_CTX_set_tlsext_servername_arg(3)>
=head1 COPYRIGHT
Copyright 2016 The OpenSSL Project Authors. All Rights Reserved.
Copyright 2016-2017 The OpenSSL Project Authors. All Rights Reserved.
Licensed under the OpenSSL license (the "License"). You may not use
this file except in compliance with the License. You can obtain a copy