Added SNI ( https://en.wikipedia.org/wiki/Server_Name_Indication ) support.

Author: Slavey Karadzhov

ssl/ssl.h

@@ -352,6 +352,16 @@ EXP_FUNC int STDCALL ssl_handshake_status(const SSL *ssl);
  */
 EXP_FUNC int STDCALL ssl_get_config(int offset);
 
+/**
+ * @brief Sets the hostname to be used for SNI
+ * @see https://en.wikipedia.org/wiki/Server_Name_Indication
+ * @param char* hostname
+ * @return success from the operation
+ * - 1 on success
+ * - 0 on failure
+ */
+EXP_FUNC int STDCALL ssl_set_hostname(const SSL *ssl, const char* host_name);
+
 /**
  * @brief Display why the handshake failed.
  *

ssl/tls1.c

@@ -1849,6 +1849,19 @@ EXP_FUNC int STDCALL ssl_get_config(int offset)
     }
 }
 
+/**
+ * Sets the SNI hostname
+ */
+EXP_FUNC int STDCALL ssl_set_hostname(const SSL *ssl, const char* host_name) {
+	if(host_name == NULL || strlen(host_name) == 0 || strlen(host_name) > 255 ) {
+		return 0;
+	}
+
+	strncpy((char*)&ssl->host_name, host_name, strlen(host_name));
+
+	return 1;
+}
+
 #ifdef CONFIG_SSL_CERT_VERIFICATION
 /**
  * Authenticate a received certificate.

ssl/tls1.h

@@ -198,6 +198,7 @@ struct _SSL
     uint8_t read_sequence[8];       /* 64 bit sequence number */
     uint8_t write_sequence[8];      /* 64 bit sequence number */
     uint8_t hmac_header[SSL_RECORD_SIZE];    /* rx hmac */
+    const char host_name[255]; /* Needed for the SNI support */
 };
 
 typedef struct _SSL SSL;

ssl/tls1_clnt.c

@@ -220,6 +220,26 @@ static int send_client_hello(SSL *ssl)
 
     buf[offset++] = 1;              /* no compression */
     buf[offset++] = 0;
+
+    if (ssl->host_name[0] != 0) {
+         unsigned int host_len = strnlen((char*) ssl->host_name, 255);
+
+         buf[offset++] = 0;
+         buf[offset++] = host_len+9;     /* extensions length */
+
+         buf[offset++] = 0;
+         buf[offset++] = 0;              /* server_name(0) (65535) */
+         buf[offset++] = 0;
+         buf[offset++] = host_len+5;     /* server_name length */
+         buf[offset++] = 0;
+         buf[offset++] = host_len+3;     /* server_list length */
+         buf[offset++] = 0;              /* host_name(0) (255) */
+         buf[offset++] = 0;
+         buf[offset++] = host_len;       /* host_name length */
+         strncpy((char*) &buf[offset], ssl->host_name, host_len);
+         offset += host_len;
+    }
+
     buf[3] = offset - 4;            /* handshake size */
 
     return send_packet(ssl, PT_HANDSHAKE_PROTOCOL, NULL, offset);