add config to change tun name (#375)

Author: GIC-de

code/bngblaster/src/bbl_config.c

@@ -4117,7 +4117,7 @@ json_parse_config(json_t *root)
 
         const char *schema[] = {
             "io-mode", "io-slots", "io-burst", "qdisc-bypass",
-            "tx-interval", "rx-interval", "tx-threads",
+            "tx-interval", "rx-interval", "tx-threads", "tun-name",
             "rx-threads", "capture-include-streams", "mac-modifier",
             "lag", "network", "access", "a10nsp", "links", "a10nsp-dynamic"
         };
@@ -4190,6 +4190,13 @@ json_parse_config(json_t *root)
         if(value) {
             g_ctx->config.a10nsp_dynamic = json_boolean_value(value);
         }
+        if(json_unpack(section, "{s:s}", "tun-name", &s) == 0) {
+            if(strlen(s) > 10) {
+                fprintf(stderr, "JSON config error: Invalid value for interfaces->tun-name (string length > 10)\n");
+                return false;
+            }
+            g_ctx->config.tun_name = strdup(s);
+        }
         /* LAG Configuration Section */
         sub = json_object_get(section, "lag");
         if(json_is_array(sub)) {
@@ -4668,6 +4675,7 @@ bbl_config_init_defaults()
     g_ctx->config.io_burst = 256;
     g_ctx->config.io_max_stream_len = 9000;
     g_ctx->config.qdisc_bypass = true;
+    g_ctx->config.tun_name = "bbl";
     g_ctx->config.sessions = 1;
     g_ctx->config.sessions_max_outstanding = 800;
     g_ctx->config.sessions_start_period_ns = 2500000; /* 400/s */

code/bngblaster/src/bbl_ctx.h

@@ -161,6 +161,7 @@ typedef struct bbl_ctx_
         uint8_t tx_threads;
         uint8_t rx_threads;
 
+        char *tun_name;
         char *json_report_filename;
         bool json_report_sessions; /* Include sessions */
         bool json_report_streams; /* Include streams */

code/bngblaster/src/bbl_tun.c

@@ -217,7 +217,7 @@ bbl_tun_session_init(bbl_session_s *session)
     char dev[IFNAMSIZ];
     if(!session->access_config->tun) return true;
 
-    snprintf(dev, sizeof(dev), "bbl%d", session->session_id);
+    snprintf(dev, sizeof(dev), "%s%d", g_ctx->config.tun_name, session->session_id);
     session->tun_dev = strdup(dev);
     session->tun_fd = bbl_tun_add(session->tun_dev, IFF_TUN|IFF_NO_PI);
 

docsrc/sources/configuration/interfaces.rst

@@ -46,4 +46,7 @@
 |                                   | | allows to run multiple BNG Blaster instances with disjoint session |
 |                                   | | MAC addresses.                                                     |
 |                                   | | Default: 0                                                         |
-+-----------------------------------+----------------------------------------------------------------------+
++-----------------------------------+----------------------------------------------------------------------+
+| **tun-name**                      | | TUN interface name prefix (`<tun-name><session-id>`).              |
+|                                   | | Default: bbl (bbl1, bbl2, ...)                                     |
++-----------------------------------+----------------------------------------------------------------------+

schemas/bngblaster-config.json

@@ -72,6 +72,10 @@
                     "minimum": 0,
                     "maximum": 255
                 },
+                "tun-name": {
+                    "type": "string",
+                    "description": "TUN interface name prefix"
+                },
                 "links": {
                     "oneOf": [
                         {