tree ab0db7113a633e70b2980f4c2dc7018e5099a0c1
parent 5cce936e622e96f47b28d3ee5156398b71d8f6a1
author Hanno Becker <hanno.becker@arm.com> 1561546035 +0100
committer Hanno Becker <hanno.becker@arm.com> 1562581073 +0100

Adapt ClientHello writing to case of single hardcoded ciphersuite

This commit modifies the ClientHello writing routine ssl_write_client_hello
in ssl_cli.c to switch between
(a) listing all runtime configured ciphersuites
    (in case MBEDTLS_SSL_SINGLE_CIPHERSUITE is not defined)
(b) listing just the single hardcoded ciphersuite
    (in case MBEDTLS_SSL_SINGLE_CIPHERSUITE is defined)

The approach taken is to introduce a pair of helper macros

  MBEDTLS_SSL_BEGIN_FOR_EACH_CIPHERSUITE( ssl, ver, info )
  MBEDTLS_SSL_END_FOR_EACH_CIPHERSUITE

which when delimiting a block of code lead to that block of
code being run once for each ciphersuite that's enabled in the
context `ssl` and version `ver`, referenced through the (fresh)
`info` variable. Internally, this is implemented either through
a plain `for` loop traversing the runtime configured ciphersuite
list (if MBEDTLS_SSL_SINGLE_CIPHERSUITE is disabled) or by just
hardcoding `info` to the single enabled ciphersuite (if
MBEDTLS_SSL_SINGLE_CIPHERSUITE is enabled).

These helper macros will prove useful whereever previous code
traversed the runtime configured ciphersuite list, but adaptations
of those occasions outside ClientHello writing are left for later
commits.