MEDIUM: ssl: Add ssl_bc_alpn and ssl_bc_npn sample fetches.

Add 2 new sample fetches, ssl_bc_alpn and ssl_bc_npn, that provides the
ALPN and the NPN for an outgoing connection.

doc/configuration.txt

@@ -14956,6 +14956,17 @@ ssl_bc_alg_keysize : integer
   Returns the symmetric cipher key size supported in bits when the outgoing
   connection was made over an SSL/TLS transport layer.
 
+ssl_bc_alpn : string
+  This extracts the Application Layer Protocol Negotiation field from an
+  outgoing connection made via a TLS transport layer.
+  The result is a string containing the protocol name negociated with the
+  server. The SSL library must have been built with support for TLS
+  extensions enabled (check haproxy -vv). Note that the TLS ALPN extension is
+  not advertised unless the "alpn" keyword on the "server" line specifies a
+  protocol list. Also, nothing forces the server to pick a protocol from this
+  list, any other one may be requested. The TLS ALPN extension is meant to
+  replace the TLS NPN extension. See also "ssl_bc_npn".
+
 ssl_bc_cipher : string
   Returns the name of the used cipher when the outgoing connection was made
   over an SSL/TLS transport layer.
@@ -14965,6 +14976,16 @@ ssl_bc_is_resumed : boolean
   layer and the newly created SSL session was resumed using a cached
   session or a TLS ticket.
 
+ssl_bc_npn : string
+  This extracts the Next Protocol Negotiation field from an outgoing connection
+  made via a TLS transport layer. The result is a string containing the
+  protocol name negociated with the server . The SSL library must have been
+  built with support for TLS extensions enabled (check haproxy -vv). Note that
+  the TLS NPN extension is not advertised unless the "npn" keyword on the
+  "server" line specifies a protocol list. Also, nothing forces the server to
+  pick a protocol from this list, any other one may be used. Please note that
+  the TLS NPN extension was replaced with ALPN.
+
 ssl_bc_protocol : string
   Returns the name of the used protocol when the outgoing connection was made
   over an SSL/TLS transport layer.

src/ssl_sock.c

@@ -6875,7 +6875,8 @@ smp_fetch_ssl_fc_npn(const struct arg *args, struct sample *smp, const char *kw,
 	smp->flags = SMP_F_CONST;
 	smp->data.type = SMP_T_STR;
 
-	conn = objt_conn(smp->sess->origin);
+	conn = (kw[4] != 'b' ) ? objt_conn(smp->sess->origin) :
+	    smp->strm ? cs_conn(objt_cs(smp->strm->si[1].end)) : NULL;
 	if (!conn || !conn->xprt_ctx || conn->xprt != &ssl_sock)
 		return 0;
 
@@ -6900,7 +6901,9 @@ smp_fetch_ssl_fc_alpn(const struct arg *args, struct sample *smp, const char *kw
 	smp->flags = SMP_F_CONST;
 	smp->data.type = SMP_T_STR;
 
-	conn = objt_conn(smp->sess->origin);
+	conn = (kw[4] != 'b' ) ? objt_conn(smp->sess->origin) :
+	    smp->strm ? cs_conn(objt_cs(smp->strm->si[1].end)) : NULL;
+
 	if (!conn || !conn->xprt_ctx || conn->xprt != &ssl_sock)
 		return 0;
 
@@ -8931,7 +8934,13 @@ static struct cli_kw_list cli_kws = {{ },{
 static struct sample_fetch_kw_list sample_fetch_keywords = {ILH, {
 	{ "ssl_bc",                 smp_fetch_ssl_fc,             0,                   NULL,    SMP_T_BOOL, SMP_USE_L5SRV },
 	{ "ssl_bc_alg_keysize",     smp_fetch_ssl_fc_alg_keysize, 0,                   NULL,    SMP_T_SINT, SMP_USE_L5SRV },
+#ifdef TLSEXT_TYPE_application_layer_protocol_negotiation
+	{ "ssl_fc_alpn",            smp_fetch_ssl_fc_alpn,        0,                   NULL,    SMP_T_STR,  SMP_USE_L5SRV },
+#endif
 	{ "ssl_bc_cipher",          smp_fetch_ssl_fc_cipher,      0,                   NULL,    SMP_T_STR,  SMP_USE_L5SRV },
+#if defined(OPENSSL_NPN_NEGOTIATED) && !defined(OPENSSL_NO_NEXTPROTONEG)
+	{ "ssl_bc_npn",             smp_fetch_ssl_fc_npn,         0,                   NULL,    SMP_T_STR,  SMP_USE_L5SRV },
+#endif
 	{ "ssl_bc_is_resumed",      smp_fetch_ssl_fc_is_resumed,  0,                   NULL,    SMP_T_BOOL, SMP_USE_L5SRV },
 	{ "ssl_bc_protocol",        smp_fetch_ssl_fc_protocol,    0,                   NULL,    SMP_T_STR,  SMP_USE_L5SRV },
 	{ "ssl_bc_unique_id",       smp_fetch_ssl_fc_unique_id,   0,                   NULL,    SMP_T_BIN,  SMP_USE_L5SRV },