diff --git a/cstp.c b/cstp.c
index d1483f5c..877b8021 100644
--- a/cstp.c
+++ b/cstp.c
@@ -219,9 +219,9 @@ static int start_cstp_connection(struct openconnect_info *vpninfo)
 	buf_append(buf, sizeof(buf), "\r\nX-DTLS-CipherSuite: %s\r\n\r\n",
 			       vpninfo->dtls_ciphers ? : DEFAULT_CIPHER_LIST);
 
-	openconnect_SSL_write(vpninfo, buf, strlen(buf));
+	vpninfo->ssl_write(vpninfo, buf, strlen(buf));
 
-	if ((i = openconnect_SSL_gets(vpninfo, buf, 65536)) < 0) {
+	if ((i = vpninfo->ssl_gets(vpninfo, buf, 65536)) < 0) {
 		if (i == -EINTR)
 			return i;
 		vpn_progress(vpninfo, PRG_ERR,
@@ -245,7 +245,7 @@ static int start_cstp_connection(struct openconnect_info *vpninfo)
 		if (!strncmp(buf, "HTTP/1.1 503 ", 13)) {
 			/* "Service Unavailable. Why? */
 			const char *reason = "<unknown>";
-			while ((i = openconnect_SSL_gets(vpninfo, buf, sizeof(buf)))) {
+			while ((i = vpninfo->ssl_gets(vpninfo, buf, sizeof(buf)))) {
 				if (!strncmp(buf, "X-Reason: ", 10)) {
 					reason = buf + 10;
 					break;
@@ -270,7 +270,7 @@ static int start_cstp_connection(struct openconnect_info *vpninfo)
 	vpninfo->deflate = 0;
 	mtu = 0;
 
-	while ((i = openconnect_SSL_gets(vpninfo, buf, sizeof(buf)))) {
+	while ((i = vpninfo->ssl_gets(vpninfo, buf, sizeof(buf)))) {
 		struct oc_vpn_option *new_option;
 		char *colon;
 
diff --git a/gnutls.c b/gnutls.c
index e5369a59..ffd84bbc 100644
--- a/gnutls.c
+++ b/gnutls.c
@@ -56,7 +56,7 @@ static P11KitPin *pin_callback(const char *pin_source, P11KitUri *pin_uri,
 #include "openconnect-internal.h"
 
 /* Helper functions for reading/writing lines over SSL. */
-int openconnect_SSL_write(struct openconnect_info *vpninfo, char *buf, size_t len)
+static int openconnect_gnutls_write(struct openconnect_info *vpninfo, char *buf, size_t len)
 {
 	size_t orig_len = len;
 
@@ -92,7 +92,7 @@ int openconnect_SSL_write(struct openconnect_info *vpninfo, char *buf, size_t le
 	return orig_len;
 }
 
-int openconnect_SSL_read(struct openconnect_info *vpninfo, char *buf, size_t len)
+static int openconnect_gnutls_read(struct openconnect_info *vpninfo, char *buf, size_t len)
 {
 	int done;
 
@@ -134,7 +134,7 @@ int openconnect_SSL_read(struct openconnect_info *vpninfo, char *buf, size_t len
 	return done;
 }
 
-int openconnect_SSL_gets(struct openconnect_info *vpninfo, char *buf, size_t len)
+static int openconnect_gnutls_gets(struct openconnect_info *vpninfo, char *buf, size_t len)
 {
 	int i = 0;
 	int ret;
@@ -1975,6 +1975,9 @@ int openconnect_open_https(struct openconnect_info *vpninfo)
 
 	vpninfo->ssl_fd = ssl_sock;
 
+	vpninfo->ssl_read = openconnect_gnutls_read;
+	vpninfo->ssl_write = openconnect_gnutls_write;
+	vpninfo->ssl_gets = openconnect_gnutls_gets;
 
 	return 0;
 }
diff --git a/http.c b/http.c
index 486c7e47..ba77c806 100644
--- a/http.c
+++ b/http.c
@@ -188,7 +188,7 @@ static int process_http_response(struct openconnect_info *vpninfo, int *result,
 	int i;
 
  cont:
-	if (openconnect_SSL_gets(vpninfo, buf, sizeof(buf)) < 0) {
+	if (vpninfo->ssl_gets(vpninfo, buf, sizeof(buf)) < 0) {
 		vpn_progress(vpninfo, PRG_ERR,
 			     _("Error fetching HTTPS response\n"));
 		openconnect_close_https(vpninfo, 0);
@@ -209,7 +209,7 @@ static int process_http_response(struct openconnect_info *vpninfo, int *result,
 		     _("Got HTTP response: %s\n"), buf);
 
 	/* Eat headers... */
-	while ((i = openconnect_SSL_gets(vpninfo, buf, sizeof(buf)))) {
+	while ((i = vpninfo->ssl_gets(vpninfo, buf, sizeof(buf)))) {
 		char *colon;
 
 		if (i < 0) {
@@ -328,7 +328,7 @@ static int process_http_response(struct openconnect_info *vpninfo, int *result,
 		if (!body)
 			return -ENOMEM;
 		while (done < bodylen) {
-			i = openconnect_SSL_read(vpninfo, body + done, bodylen - done);
+			i = vpninfo->ssl_read(vpninfo, body + done, bodylen - done);
 			if (i < 0) {
 				vpn_progress(vpninfo, PRG_ERR,
 					     _("Error reading HTTP response body\n"));
@@ -340,7 +340,7 @@ static int process_http_response(struct openconnect_info *vpninfo, int *result,
 		}
 	} else if (bodylen == BODY_CHUNKED) {
 		/* ... else, chunked */
-		while ((i = openconnect_SSL_gets(vpninfo, buf, sizeof(buf)))) {
+		while ((i = vpninfo->ssl_gets(vpninfo, buf, sizeof(buf)))) {
 			int chunklen, lastchunk = 0;
 
 			if (i < 0) {
@@ -357,7 +357,7 @@ static int process_http_response(struct openconnect_info *vpninfo, int *result,
 			if (!body)
 				return -ENOMEM;
 			while (chunklen) {
-				i = openconnect_SSL_read(vpninfo, body + done, chunklen);
+				i = vpninfo->ssl_read(vpninfo, body + done, chunklen);
 				if (i < 0) {
 					vpn_progress(vpninfo, PRG_ERR,
 						     _("Error reading HTTP response body\n"));
@@ -368,7 +368,7 @@ static int process_http_response(struct openconnect_info *vpninfo, int *result,
 				done += i;
 			}
 		skip:
-			if ((i = openconnect_SSL_gets(vpninfo, buf, sizeof(buf)))) {
+			if ((i = vpninfo->ssl_gets(vpninfo, buf, sizeof(buf)))) {
 				if (i < 0) {
 					vpn_progress(vpninfo, PRG_ERR,
 						     _("Error fetching HTTP response body\n"));
@@ -397,7 +397,7 @@ static int process_http_response(struct openconnect_info *vpninfo, int *result,
 			realloc_inplace(body, done + 16384);
 			if (!body)
 				return -ENOMEM;
-			i = openconnect_SSL_read(vpninfo, body + done, 16384);
+			i = vpninfo->ssl_read(vpninfo, body + done, 16384);
 			if (i > 0) {
 				/* Got more data */
 				done += i;
@@ -495,7 +495,7 @@ static int fetch_config(struct openconnect_info *vpninfo)
 	if (buf_error(buf))
 		return buf_free(buf);
 
-	if (openconnect_SSL_write(vpninfo, buf->data, buf->pos) != buf->pos) {
+	if (vpninfo->ssl_write(vpninfo, buf->data, buf->pos) != buf->pos) {
 		vpn_progress(vpninfo, PRG_ERR,
 			     _("Failed to send GET request for new config\n"));
 		buf_free(buf);
@@ -954,7 +954,7 @@ static int do_https_request(struct openconnect_info *vpninfo, const char *method
 	if (vpninfo->dump_http_traffic)
 		dump_buf(vpninfo, '>', buf->data);
 
-	result = openconnect_SSL_write(vpninfo, buf->data, buf->pos);
+	result = vpninfo->ssl_write(vpninfo, buf->data, buf->pos);
 	if (rq_retry && result < 0) {
 		openconnect_close_https(vpninfo, 0);
 		goto retry;
diff --git a/openconnect-internal.h b/openconnect-internal.h
index 15cfe19b..799a1f16 100644
--- a/openconnect-internal.h
+++ b/openconnect-internal.h
@@ -334,6 +334,10 @@ struct openconnect_info {
 	openconnect_process_auth_form_vfn process_auth_form;
 	openconnect_progress_vfn progress;
 	openconnect_protect_socket_vfn protect_socket;
+
+	int (*ssl_read)(struct openconnect_info *vpninfo, char *buf, size_t len);
+	int (*ssl_gets)(struct openconnect_info *vpninfo, char *buf, size_t len);
+	int (*ssl_write)(struct openconnect_info *vpninfo, char *buf, size_t len);
 };
 
 #ifdef _WIN32
@@ -498,9 +502,6 @@ int is_cancel_pending(struct openconnect_info *vpninfo, fd_set *fds);
 void poll_cmd_fd(struct openconnect_info *vpninfo, int timeout);
 
 /* {gnutls,openssl}.c */
-int openconnect_SSL_gets(struct openconnect_info *vpninfo, char *buf, size_t len);
-int openconnect_SSL_write(struct openconnect_info *vpninfo, char *buf, size_t len);
-int openconnect_SSL_read(struct openconnect_info *vpninfo, char *buf, size_t len);
 int openconnect_open_https(struct openconnect_info *vpninfo);
 void openconnect_close_https(struct openconnect_info *vpninfo, int final);
 int cstp_handshake(struct openconnect_info *vpninfo, unsigned init);
diff --git a/openssl.c b/openssl.c
index ecd56a06..871eef68 100644
--- a/openssl.c
+++ b/openssl.c
@@ -78,7 +78,7 @@ int openconnect_random(void *bytes, int len)
 /* Helper functions for reading/writing lines over SSL.
    We could use cURL for the HTTP stuff, but it's overkill */
 
-int openconnect_SSL_write(struct openconnect_info *vpninfo, char *buf, size_t len)
+static int openconnect_openssl_write(struct openconnect_info *vpninfo, char *buf, size_t len)
 {
 	size_t orig_len = len;
 
@@ -115,7 +115,7 @@ int openconnect_SSL_write(struct openconnect_info *vpninfo, char *buf, size_t le
 	return orig_len;
 }
 
-int openconnect_SSL_read(struct openconnect_info *vpninfo, char *buf, size_t len)
+static int openconnect_openssl_read(struct openconnect_info *vpninfo, char *buf, size_t len)
 {
 	int done;
 
@@ -146,7 +146,7 @@ int openconnect_SSL_read(struct openconnect_info *vpninfo, char *buf, size_t len
 	return done;
 }
 
-int openconnect_SSL_gets(struct openconnect_info *vpninfo, char *buf, size_t len)
+static int openconnect_openssl_gets(struct openconnect_info *vpninfo, char *buf, size_t len)
 {
 	int i = 0;
 	int ret;
@@ -1413,6 +1413,10 @@ int openconnect_open_https(struct openconnect_info *vpninfo)
 	vpninfo->ssl_fd = ssl_sock;
 	vpninfo->https_ssl = https_ssl;
 
+	vpninfo->ssl_read = openconnect_openssl_read;
+	vpninfo->ssl_write = openconnect_openssl_write;
+	vpninfo->ssl_gets = openconnect_openssl_gets;
+
 	/* Stash this now, because it might not be available later if the
 	   server has disconnected. */
 	vpninfo->peer_cert = SSL_get_peer_certificate(vpninfo->https_ssl);
diff --git a/ssl.c b/ssl.c
index cfd057b9..3d15fcbc 100644
--- a/ssl.c
+++ b/ssl.c
@@ -317,7 +317,7 @@ int  __attribute__ ((format (printf, 2, 3)))
 	va_start(args, fmt);
 	vsnprintf(buf, 1023, fmt, args);
 	va_end(args);
-	return openconnect_SSL_write(vpninfo, buf, strlen(buf));
+	return vpninfo->ssl_write(vpninfo, buf, strlen(buf));
 
 }