Clean up compression type handling

This makes it slightly easier to add new compression types.

[dwmw2: Split out from "Added support for LZ4" patch and tweaked a little.]

Signed-off-by: Nikos Mavrogiannopoulos <nmav@gnutls.org>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

cstp.c

@@ -150,6 +150,23 @@ void cstp_free_splits(struct openconnect_info *vpninfo)
 # define DEFAULT_CIPHER_LIST "AES256-SHA:AES128-SHA:DES-CBC3-SHA:DES-CBC-SHA"
 #endif
 
+static void append_compr_types(struct oc_text_buf *buf, const char *proto, int avail)
+{
+	if (avail) {
+		char sep = ' ';
+		buf_append(buf, "X-%s-Accept-Encoding:", proto);
+		if (avail & COMPR_LZS) {
+			buf_append(buf, "%clzs", sep);
+			sep = ',';
+		}
+		if (avail & COMPR_DEFLATE) {
+			buf_append(buf, "%cdeflate", sep);
+			sep = ',';
+		}
+		buf_append(buf, "\r\n");
+	}
+}
+
 static int start_cstp_connection(struct openconnect_info *vpninfo)
 {
 	struct oc_text_buf *reqbuf;
@@ -188,19 +205,9 @@ static int start_cstp_connection(struct openconnect_info *vpninfo)
 	buf_append(reqbuf, "Cookie: webvpn=%s\r\n", vpninfo->cookie);
 	buf_append(reqbuf, "X-CSTP-Version: 1\r\n");
 	buf_append(reqbuf, "X-CSTP-Hostname: %s\r\n", vpninfo->localname);
-	if (vpninfo->req_compr) {
-		char sep = ' ';
-		buf_append(reqbuf, "X-CSTP-Accept-Encoding:");
-		if (vpninfo->req_compr & COMPR_LZS) {
-			buf_append(reqbuf, "%clzs", sep);
-			sep = ',';
-		}
-		if (vpninfo->req_compr & COMPR_DEFLATE) {
-			buf_append(reqbuf, "%cdeflate", sep);
-			sep = ',';
-		}
-		buf_append(reqbuf, "\r\n");
-	}
+
+	append_compr_types(reqbuf, "CSTP", vpninfo->req_compr & ~COMPR_DEFLATE);
+
 	if (base_mtu)
 		buf_append(reqbuf, "X-CSTP-Base-MTU: %d\r\n", base_mtu);
 	buf_append(reqbuf, "X-CSTP-MTU: %d\r\n", mtu);
@@ -220,8 +227,8 @@ static int start_cstp_connection(struct openconnect_info *vpninfo)
 	}
 	buf_append(reqbuf, "\r\nX-DTLS-CipherSuite: %s\r\n",
 			       vpninfo->dtls_ciphers ? : DEFAULT_CIPHER_LIST);
-	if (vpninfo->req_compr & COMPR_LZS)
-		buf_append(reqbuf, "X-DTLS-Accept-Encoding: lzs\r\n");
+
+	append_compr_types(reqbuf, "DTLS", vpninfo->req_compr);
 	buf_append(reqbuf, "\r\n");
 
 	if (buf_error(reqbuf)) {

main.c

@@ -931,6 +931,7 @@ int main(int argc, char **argv)
 {
 	struct openconnect_info *vpninfo;
 	char *urlpath = NULL;
+	const char *compr = "";
 	char *proxy = getenv("https_proxy");
 	char *vpnc_script = NULL, *ifname = NULL;
 	const struct oc_ip_info *ip_info;
@@ -1423,15 +1424,25 @@ int main(int argc, char **argv)
 		fprintf(stderr, _("Set up DTLS failed; using SSL instead\n"));
 
 	openconnect_get_ip_info(vpninfo, &ip_info, NULL, NULL);
+
+	if (vpninfo->dtls_state != DTLS_CONNECTED) {
+		if (vpninfo->cstp_compr == COMPR_DEFLATE)
+			compr = " + deflate";
+		else if (vpninfo->cstp_compr == COMPR_LZS)
+			compr = " + lzs";
+	} else {
+		if (vpninfo->dtls_compr == COMPR_DEFLATE)
+			compr = " + deflate";
+		else if (vpninfo->dtls_compr == COMPR_LZS)
+			compr = " + lzs";
+	}
 	vpn_progress(vpninfo, PRG_INFO,
-		     _("Connected %s as %s%s%s, using %s\n"), openconnect_get_ifname(vpninfo),
+		     _("Connected %s as %s%s%s, using %s%s\n"), openconnect_get_ifname(vpninfo),
 		     ip_info->addr?:"",
 		     (ip_info->netmask6 && ip_info->addr) ? " + " : "",
 		     ip_info->netmask6 ? : "",
-		     (vpninfo->dtls_state != DTLS_CONNECTED) ?
-		     (vpninfo->cstp_compr == COMPR_DEFLATE) ? "SSL + deflate" :
-		     (vpninfo->cstp_compr == COMPR_LZS) ? "SSL + lzs" : "SSL"
-		     : "DTLS");
+		     (vpninfo->dtls_state != DTLS_CONNECTED) ? "SSL"
+		     : "DTLS", compr);
 
 	if (!vpninfo->vpnc_script) {
 		vpn_progress(vpninfo, PRG_INFO,