Allow NPN enable on a per-SSL connection basis...

openssl/ssl/ssl_lib.c

Index: openssl/ssl/ssl_lib.c
===================================================================
--- openssl/ssl/ssl_lib.c	(revision 65717)
+++ openssl/ssl/ssl_lib.c	(working copy)
@@ -324,6 +324,9 @@
 	CRYPTO_add(&ctx->references,1,CRYPTO_LOCK_SSL_CTX);
 	s->initial_ctx=ctx;
 	s->next_proto_negotiated = NULL;
+	s->next_proto_negotiated_len = 0;
+	s->next_proto_select_cb	= ctx->next_proto_select_cb;
+	s->next_proto_select_cb_arg	= ctx->next_proto_select_cb_arg;
 #endif
 	s->verify_result=X509_V_OK;
 
@@ -2870,9 +2873,12 @@
  * The length of the protocol name must be written into |outlen|. The server's
  * advertised protocols are provided in |in| and |inlen|. The callback can
  * assume that |in| is syntactically valid.
+ * A side effect of calling this method with a non-NULL |cb| is to enable NPN
+ * for all SSLs subsequently created from this CTX. Passing a NULL |cb| resets
+ * the CTX so future connections will not use NPN.
  *
- * The client must select a protocol. It is fatal to the connection if this
- * callback returns a value other than SSL_TLSEXT_ERR_OK.
+ * When enabled, the client must select a protocol. It is fatal to the
+ * connection if this callback returns a value other than SSL_TLSEXT_ERR_OK.
  */
 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)
 	{
@@ -2880,6 +2886,19 @@
 	ctx->next_proto_select_cb_arg = arg;
 	}
 
+/* SSL_set_next_proto_select_cb is a per-connection alternative to
+ * SSL_CTX_set_next_proto_select_cb, see that function for full description of
+ * the parameters.
+ * This method may also be used to modify a CTX default, for example disable
+ * NPN by passing a NULL |cb| or modify the callback argument by passing a
+ * valid |cb| and an updated |arg|.
+ */
+void SSL_set_next_proto_select_cb(SSL *s, int (*cb) (SSL *ssl, unsigned char **out, unsigned char *outlen, const unsigned char *in, unsigned int inlen, void *arg), void *arg)
+  {
+	s->next_proto_select_cb = cb;
+	s->next_proto_select_cb_arg = arg;
+  }
+
 /* SSL_CTX_set_snap_start_orbit sets the orbit value which will be echoed back
  * to the client and enables Snap Start for this context.
  *