+
+
+/*
+ * Process the ALPN extension in a ClientHello.
+ * al: a pointer to the alert value to send in the event of a failure.
+ * returns 1 on success, 0 on error.
+ */
+static int tls_ext_final_alpn(SSL *s, unsigned int context, int sent, int *al)
+{
+ const unsigned char *selected = NULL;
+ unsigned char selected_len = 0;
+
+ if (!s->server)
+ return 1;
+
+ if (s->ctx->alpn_select_cb != NULL && s->s3->alpn_proposed != NULL) {
+ int r = s->ctx->alpn_select_cb(s, &selected, &selected_len,
+ s->s3->alpn_proposed,
+ (unsigned int)s->s3->alpn_proposed_len,
+ s->ctx->alpn_select_cb_arg);
+
+ if (r == SSL_TLSEXT_ERR_OK) {
+ OPENSSL_free(s->s3->alpn_selected);
+ s->s3->alpn_selected = OPENSSL_memdup(selected, selected_len);
+ if (s->s3->alpn_selected == NULL) {
+ *al = SSL_AD_INTERNAL_ERROR;
+ return 0;
+ }
+ s->s3->alpn_selected_len = selected_len;
+#ifndef OPENSSL_NO_NEXTPROTONEG
+ /* ALPN takes precedence over NPN. */
+ s->s3->next_proto_neg_seen = 0;
+#endif
+ } else {
+ *al = SSL_AD_NO_APPLICATION_PROTOCOL;
+ return 0;
+ }
+ }
+
+ return 1;
+}
+