--- a/cli-agentfwd.c	Tue Jan 23 23:27:40 2018 +0800
+++ b/cli-agentfwd.c	Sat Feb 17 19:29:51 2018 +0800
@@ -108,7 +108,7 @@
    data        Any data, depending on packet type.  Encoding as in the ssh packet
                protocol.
 */
-static buffer * agent_request(unsigned char type, buffer *data) {
+static buffer * agent_request(unsigned char type, const buffer *data) {
 
 	buffer * payload = NULL;
 	buffer * inbuf = NULL;
@@ -230,7 +230,7 @@
 	}
 }
 
-void cli_setup_agent(struct Channel *channel) {
+void cli_setup_agent(const struct Channel *channel) {
 	if (!getenv("SSH_AUTH_SOCK")) {
 		return;
 	}
@@ -254,7 +254,7 @@
 }
 
 void agent_buf_sign(buffer *sigblob, sign_key *key, 
-		buffer *data_buf) {
+		const buffer *data_buf) {
 	buffer *request_data = NULL;
 	buffer *response = NULL;
 	unsigned int siglen;