Merge pull request #1126 from tperard/fix-network-auto-detection

Fix network interface auto detection

include/modules/network.hpp

@@ -72,6 +72,7 @@ class Network : public ALabel {
   int32_t     signal_strength_dbm_;
   uint8_t     signal_strength_;
   uint32_t    frequency_;
+  uint32_t    route_priority;
 
   util::SleeperThread thread_;
   util::SleeperThread thread_timer_;

src/modules/network.cpp

@@ -1,6 +1,7 @@
 #include "modules/network.hpp"
 #include <spdlog/spdlog.h>
 #include <sys/eventfd.h>
+#include <linux/if.h>
 #include <fstream>
 #include <cassert>
 #include <optional>
@@ -400,6 +401,7 @@ bool waybar::modules::Network::checkInterface(std::string name) {
 
 void waybar::modules::Network::clearIface() {
   ifid_ = -1;
+  ifname_.clear();
   essid_.clear();
   ipaddr_.clear();
   netmask_.clear();
@@ -431,6 +433,20 @@ int waybar::modules::Network::handleEvents(struct nl_msg *msg, void *data) {
       return NL_OK;
     }
 
+    // Check if the interface goes "down" and if we want to detect the
+    // external interface.
+    if (net->ifid_ != -1 && !(ifi->ifi_flags & IFF_UP)
+        && !net->config_["interface"].isString()) {
+      // The current interface is now down, all the routes associated with
+      // it have been deleted, so start looking for a new default route.
+      spdlog::debug("network: if{} down", net->ifid_);
+      net->clearIface();
+      net->dp.emit();
+      net->want_route_dump_ = true;
+      net->askForStateDump();
+      return NL_OK;
+    }
+
     for (; RTA_OK(ifla, attrlen); ifla = RTA_NEXT(ifla, attrlen)) {
       switch (ifla->rta_type) {
       case IFLA_IFNAME:
@@ -572,11 +588,7 @@ int waybar::modules::Network::handleEvents(struct nl_msg *msg, void *data) {
     bool           has_gateway = false;
     bool           has_destination = false;
     int            temp_idx = -1;
-
+    uint32_t       priority = 0;
-    /* If we found the correct answer, skip parsing the attributes. */
-    if (!is_del_event && net->ifid_ != -1) {
-      return NL_OK;
-    }
 
     /* Find the message(s) concerting the main routing table, each message
      * corresponds to a single routing table entry.
@@ -620,18 +632,26 @@ int waybar::modules::Network::handleEvents(struct nl_msg *msg, void *data) {
         /* The output interface index. */
         temp_idx = *static_cast<int *>(RTA_DATA(attr));
         break;
+      case RTA_PRIORITY:
+        priority = *(uint32_t*)RTA_DATA(attr);
+        break;
       default:
         break;
       }
+    }
 
-      /* If this is the default route, and we know the interface index,
+    // Check if we have a default route.
-       * we can stop parsing this message.
-       */
     if (has_gateway && !has_destination && temp_idx != -1) {
-        if (!is_del_event) {
+      // Check if this is the first default route we see, or if this new
+      // route have a higher priority.
+      if (!is_del_event && ((net->ifid_ == -1) || (priority < net->route_priority))) {
+        // Clear if's state for the case were there is a higher priority
+        // route on a different interface.
+        net->clearIface();
         net->ifid_ = temp_idx;
+        net->route_priority = priority;
 
-          spdlog::debug("network: new default route via if{}", temp_idx);
+        spdlog::debug("network: new default route via if{} metric {}", temp_idx, priority);
 
         /* Ask ifname associated with temp_idx as well as carrier status */
         struct ifinfomsg ifinfo_hdr = {
@@ -653,11 +673,11 @@ int waybar::modules::Network::handleEvents(struct nl_msg *msg, void *data) {
         net->want_addr_dump_ = true;
         net->askForStateDump();
         net->thread_timer_.wake_up();
-        } else if (is_del_event && temp_idx == net->ifid_) {
+      } else if (is_del_event && temp_idx == net->ifid_
-          spdlog::debug("network: default route deleted {}/if{}",
+                 && net->route_priority == priority) {
-                        net->ifname_, temp_idx);
+        spdlog::debug("network: default route deleted {}/if{} metric {}",
+                      net->ifname_, temp_idx, priority);
 
-          net->ifname_.clear();
         net->clearIface();
         net->dp.emit();
         /* Ask for a dump of all routes in case another one is already
@@ -667,7 +687,6 @@ int waybar::modules::Network::handleEvents(struct nl_msg *msg, void *data) {
         net->askForStateDump();
       }
     }
-    }
     break;
   }
   }