Provide more robust (inline) functions to replace n2s, n2l, etc. These
functions do the same thing as the previous macros, but also keep track
of the amount of data remaining and return an error if we try to read more
data than we've got.

Reviewed-by: Tim Hudson <tjh@openssl.org>

Reviewed-by: Rich Salz <rsalz@openssl.org>

Reviewed-by: Richard Levitte <levitte@openssl.org>

Reviewed-by: Rich Salz <rsalz@openssl.org>

Reviewed-by: Rich Salz <rsalz@openssl.org>

Reviewed-by: Richard Levitte

Reviewed-by: Richard Levitte <levitte@openssl.org>

Reviewed-by: Rich Salz <rsalz@openssl.org>

Commit e481f9b9 removed OPENSSL_NO_TLSEXT from the code.

Previously if OPENSSL_NO_TLSEXT *was not* defined then the server random was
filled during getting of the ClientHello. If it *was* defined then the
server random would be filled in ssl3_send_server_hello(). Unfortunately in
commit e481f9b9

 the OPENSSL_NO_TLSEXT guards were removed but *both*
server random fillings were left in. This could cause problems for session
ticket callbacks.

Reviewed-by: Stephen Henson <steve@openssl.org>

From a CloudFlare patch.

Reviewed-by: Dr. Stephen Henson <steve@openssl.org>

Thanks folks:
        348 Benjamin Kaduk
        317 Christian Brueffer
        254 Erik Tews
        253 Erik Tews
        219 Carl Mehner
        155 (ghost)
        95 mancha
        51 DominikNeubauer

Reviewed-by: Dr. Stephen Henson <steve@openssl.org>

Reviewed-by: Matt Caswell <matt@openssl.org>

Reviewed-by: Matt Caswell <matt@openssl.org>

Reviewed-by: Matt Caswell <matt@openssl.org>

Reviewed-by: Matt Caswell <matt@openssl.org>

Reviewed-by: Matt Caswell <matt@openssl.org>

Reviewed-by: Matt Caswell <matt@openssl.org>

Reviewed-by: Matt Caswell <matt@openssl.org>

Reviewed-by: Matt Caswell <matt@openssl.org>

Reviewed-by: Matt Caswell <matt@openssl.org>

Reviewed-by: Matt Caswell <matt@openssl.org>

Reviewed-by: Matt Caswell <matt@openssl.org>

Reviewed-by: Matt Caswell <matt@openssl.org>

Note: some of the RFC4279 ciphersuites were originally part of PR#2464.

Reviewed-by: Matt Caswell <matt@openssl.org>

Reviewed-by: Matt Caswell <matt@openssl.org>

Reviewed-by: Matt Caswell <matt@openssl.org>

Move PSK premaster secret algorithm to ssl_generate_master secret so
existing key exchange code can be used and modified slightly to add
the PSK wrapping structure.

Reviewed-by: Matt Caswell <matt@openssl.org>

Add support for RSAPSK, DHEPSK and ECDHEPSK server side.

Update various checks to ensure certificate and server key exchange messages
are only sent when required.

Update message handling. PSK server key exchange parsing now include an
identity hint prefix for all PSK server key exchange messages. PSK
client key exchange message expects PSK identity and requests key for
all PSK key exchange ciphersuites.

Update flags for RSA, DH and ECDH so they are also used in PSK.

Reviewed-by: Matt Caswell <matt@openssl.org>

Add support for RSAPSK, DHEPSK and ECDHEPSK client side.

Update various checks to ensure certificate and server key exchange messages
are only expected when required.

Update message handling. PSK server key exchange parsing now expects an
identity hint prefix for all PSK server key exchange messages. PSK
client key exchange message requests PSK identity and key for all PSK
key exchange ciphersuites and includes identity in message.

Update flags for RSA, DH and ECDH so they are also used in PSK.

Reviewed-by: Matt Caswell <matt@openssl.org>

For SHA384 PRF PSK ciphersuites we have to switch to default PRF for
TLS < 1.2

Reviewed-by: Matt Caswell <matt@openssl.org>

Reviewed-by: Matt Caswell <matt@openssl.org>

Reviewed-by: Matt Caswell <matt@openssl.org>

Reviewed-by: Matt Caswell <matt@openssl.org>

Reviewed-by: Matt Caswell <matt@openssl.org>

Reviewed-by: Matt Caswell <matt@openssl.org>

Reviewed-by: Matt Caswell <matt@openssl.org>

Reviewed-by: Matt Caswell <matt@openssl.org>

Reviewed-by: Matt Caswell <matt@openssl.org>

Reviewed-by: Matt Caswell <matt@openssl.org>

The DTLS code is supposed to drop packets if we try to write them out but
the underlying BIO write buffers are full. ssl3_write_pending() contains
an incorrect test for DTLS that controls this. The test only checks for
DTLS1 so DTLS1.2 does not correctly clear the internal OpenSSL buffer which
can later cause an assert to be hit. This commit changes the test to cover
all DTLS versions.

RT#3967

Reviewed-by: Tim Hudson <tjh@openssl.org>