Yeah, I agree. Right now, trunk pretty much uses

        #ifdef HAVE_TLS_ALPN
        blah blah
        #endif
        #ifdef HAVE_TLS_NPN
        blah2 blah2
        #endif

Instead of

        #if defined(HAVE_TLS_NPN) || defined(HAVE_TLS_ALPN)

so that "ripping out" NPN would be easier. The question is
which to use for 2.4...

> On Apr 1, 2015, at 1:59 PM, Stefan Eissing <stefan.eiss...@greenbytes.de> 
> wrote:
> 
> Well, I took the trunk version, diffed to 2.4.12 and made a patch for my 
> sandbox build (removed the non alpn/npn parts). That works for mod_h2 after 
> adding callbacks for the npn stuff. 
> 
> I have no real pref to keep npn and alpn separate or not. my thought when 
> merging these was that npn will go away rather soon as alpn is supposed to 
> replace it and is afaik the cryptographically more secure way (i think npn is 
> prone to mitm downgrade attacks). 
> 
> cheers,
>  Stefan
> 
> 
> 
>> Am 01.04.2015 um 19:28 schrieb Jim Jagielski <j...@jagunet.com>:
>> 
>> Yeah, there is some "overlap" which I'm trying to grok,
>> since trunk had NPN but not ALPN, so I tried to have the
>> ALPN stuff self-contained. But not sure if that's the best
>> way since, for example, alpn_proposefns is adjusted
>> in ssl_callback_AdvertiseNextProtos(), but that is a
>> NPN "only" function in trunk, so it uses npn_proposefns.
>> 
>> I'm thinking that in trunk we shouldn't think of
>> NPN and ALPN as "distinct".
>> 
>>> On Apr 1, 2015, at 12:47 PM, Rainer Jung <rainer.j...@kippdata.de> wrote:
>>> 
>>> Hi Stefan,
>>> 
>>>> Am 01.04.2015 um 18:22 schrieb Stefan Eissing:
>>>> Jim,
>>>> 
>>>> today I converted your commit to a path on 2.4.12 and tested it with 
>>>> mod_h2. All fine!
>>>> 
>>>> Then I got a trouble report that alpn negotiation always selected 
>>>> "http/1.1" unless SSLAlpnPreference configured something else. This is due 
>>>> to the deterministic ordering and "http/1.1." > "h2". So, I made a slight 
>>>> modification, attached below.
>>> 
>>> Maybe related but concerning NPN: There was a difference between the NPN 
>>> parts of your original Bugzilla attachment and what was already in mod_ssl 
>>> trunk and therefore was not applied. In your attachment, there was some 
>>> code for sorting in ssl_callback_AdvertiseNextProtos() which IMHO does not 
>>> exist in trunk. Is that part necessary?
>>> 
>>> A second difference: your original addition to ssl_engine_io.c had the NPN 
>>> and the ALPN parts merged in the same code block. In trunk those are now 
>>> two separate pieces coming after each other.
>>> 
>>>> --- modules/ssl/ssl_engine_kernel.c    2015-04-01 15:23:48.000000000 +0200
>>>> +++ 
>>>> ../../mod-h2/sandbox/httpd/gen/httpd-2.4.12/modules/ssl/ssl_engine_kernel.c
>>>>     2015-04-01 17:53:03.000000000 +0200
>>>> @@ -2177,7 +2152,7 @@
>>>> }
>>>> 
>>>> /*
>>>> - * Compare to ALPN protocol proposal. Result is similar to strcmp():
>>>> + * Compare two ALPN protocol proposal. Result is similar to strcmp():
>>>> * 0 gives same precedence, >0 means proto1 is prefered.
>>>> */
>>>> static int ssl_cmp_alpn_protos(modssl_ctx_t *ctx,
>>>> @@ -2254,14 +2229,8 @@
>>>>        i += plen;
>>>>    }
>>>> 
>>>> -    /* Regardless of installed hooks, the http/1.1 protocol is always
>>>> -     * supported by us. Add it to the proposals if the client also
>>>> -     * offers it. */
>>>>    proposed_protos = apr_array_make(c->pool, client_protos->nelts+1,
>>>>                                     sizeof(char *));
>>>> -    if (ssl_array_index(client_protos, alpn_http1) >= 0) {
>>>> -        APR_ARRAY_PUSH(proposed_protos, const char*) = alpn_http1;
>>>> -    }
>>>> 
>>>>    if (sslconn->alpn_proposefns != NULL) {
>>>>        /* Invoke our alpn_propos_proto hooks, giving other modules a 
>>>> chance to
>>>> @@ -2280,9 +2249,16 @@
>>>>    }
>>>> 
>>>>    if (proposed_protos->nelts <= 0) {
>>>> -        ap_log_cerror(APLOG_MARK, APLOG_ERR, 0, c, APLOGNO(02839)
>>>> -                      "none of the client alpn protocols are supported");
>>>> -        return SSL_TLSEXT_ERR_ALERT_FATAL;
>>>> +        /* Regardless of installed hooks, the http/1.1 protocol is always
>>>> +         * supported by us. Choose it if none other matches. */
>>>> +        if (ssl_array_index(client_protos, alpn_http1) < 0) {
>>>> +            ap_log_cerror(APLOG_MARK, APLOG_ERR, 0, c, APLOGNO(02839)
>>>> +                          "none of the client alpn protocols are 
>>>> supported");
>>>> +            return SSL_TLSEXT_ERR_ALERT_FATAL;
>>>> +        }
>>>> +        *out = (const unsigned char*)alpn_http1;
>>>> +        *outlen = (unsigned char)strlen(alpn_http1);
>>>> +        return SSL_TLSEXT_ERR_OK;
>>>>    }
>>>> 
>>>>    /* Now select the most preferred protocol from the proposals. */
>> 

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