sip: attempt reconnection anytime network is routable, not just when routability changes

this resolves an issue where the network could be routable but DNS had
failed, and CallsSipOrigin settled into the offline state with
`CALLS_ACCOUNT_STATE_REASON_CONNECTION_DNS_ERROR`. in this situation, we
now attempt a reconnection every 15s, instead of waiting for the network
to go down and back up again.

default.nix

@@ -4,7 +4,43 @@
 { pkgs ? import <nixpkgs> {} }:
 let
   inherit (pkgs) stdenv;
-in stdenv.mkDerivation {
+  buildDebug = p: p.overrideAttrs (base: {
+    dontStrip = true;
+    env = (base.env or {}) // {
+      mesonBuildType = "debugoptimized";
+      NIX_CFLAGS_COMPILE = "-ggdb -Og -fno-omit-frame-pointer";
+      # mesonBuildType = "debug";
+      # NIX_CFLAGS_COMPILE = "-g -O0 -fno-omit-frame-pointer";
+    };
+  });
+  sofia_sip' = pkgs.sofia_sip.overrideAttrs (base: {
+    # sofia_sip linphone fork (2024-08-17)
+    # it seems to have less buggy DNS (sresolv)? the DNS actually reports errors to the consumer, instead of just never returning.
+    # more specifically, `outgoing_answer_a` always calls its continuation: that's actually in libsofia-sip-ua/nta/nta.c
+    src = with pkgs; fetchFromGitLab {
+      domain = "gitlab.linphone.org";
+      owner = "BC/public/external";
+      repo = "sofia-sip";
+      rev = "b924a57e8eeb24e8b9afc5fd0fb9b51d5993fe5d";
+      hash = "sha256-1VbKV+eAJ80IMlubNl7774B7QvLv4hE8SXANDSD9sRU=";
+    };
+  });
+  # sofia_sip' = pkgs.sofia_sip.overrideAttrs (base: {
+  #   # sofia_sip tip (2024-08-17)
+  #   src = with pkgs; fetchFromGitHub {
+  #     owner = "freeswitch";
+  #     repo = "sofia-sip";
+  #     rev = "0a50b8402fa5b6190a6c91c2e04dfe44a40de02c";
+  #     hash = "sha256-cxLk0IEwpoxeuVllnZ4/6JqzCd0GVeLyulFj0EYgnek=";
+  #   };
+  # });
+  # sofia_sip' = pkgs.sofia_sip.overrideAttrs (base: {
+  #   postPatch = (base.postPatch or "") + ''
+  #     substituteInPlace libsofia-sip-ua/sresolv/sofia-resolv/sres.h \
+  #       --replace 'SRES_MAX_RETRY_COUNT = 6' 'SRES_MAX_RETRY_COUNT = 0'
+  #   '';
+  # });
+in buildDebug (stdenv.mkDerivation {
   pname = "calls";
   version = "unstable";
   src = ./.;
@@ -41,6 +77,6 @@ in stdenv.mkDerivation {
     libpeas2
     libsecret
     modemmanager
-    sofia_sip
+    (buildDebug sofia_sip')
   ];
-}
+})

plugins/provider/sip/calls-sip-origin.c

@@ -1105,6 +1105,12 @@ go_online (CallsAccount *account,
   }
 }
 
+static void
+go_online_opportunistically (CallsSipOrigin *self)
+{
+  if (self->auto_connect)
+    go_online (CALLS_ACCOUNT (self), TRUE);
+}
 
 static const char *
 get_address (CallsAccount *account)
@@ -1706,10 +1712,12 @@ calls_sip_origin_init (CallsSipOrigin *self)
 
   if (!sip_test_env || sip_test_env[0] == '\0') {
     CallsNetworkWatch *nw = calls_network_watch_get_default ();
-    if (nw)
+    if (nw) {
       g_signal_connect_swapped (calls_network_watch_get_default (), "network-changed",
                                 G_CALLBACK (recreate_sip), self);
-    else
+      g_signal_connect_swapped (calls_network_watch_get_default (), "network-routable",
+                                G_CALLBACK (go_online_opportunistically), self);
+    } else
       g_warning ("Network watch unavailable. Unable to detect network changes.");
   }
 

src/calls-network-watch.c

@@ -61,6 +61,7 @@ static GParamSpec *props[PROP_LAST_PROP];
 
 enum {
   NETWORK_CHANGED,
+  NETWORK_ROUTABLE,
   N_SIGNALS
 };
 static guint signals[N_SIGNALS];
@@ -282,10 +283,12 @@ fetch_ipv6 (CallsNetworkWatch *self)
 static gboolean
 on_watch_network (CallsNetworkWatch *self)
 {
+  gboolean has_v4 = fetch_ipv4 (self);
+  gboolean has_v6 = fetch_ipv6 (self);
   gboolean changed_v4 = FALSE;
   gboolean changed_v6 = FALSE;
 
-  changed_v4 = fetch_ipv4 (self) && g_strcmp0 (self->tmp_addr, self->ipv4) != 0;
+  changed_v4 = has_v4 && g_strcmp0 (self->tmp_addr, self->ipv4) != 0;
   if (changed_v4) {
     g_free (self->ipv4);
     self->ipv4 = g_strdup (self->tmp_addr);
@@ -293,7 +296,7 @@ on_watch_network (CallsNetworkWatch *self)
     g_object_notify_by_pspec (G_OBJECT (self), props[PROP_IPV4]);
   }
 
-  changed_v6 = fetch_ipv6 (self) && g_strcmp0 (self->tmp_addr, self->ipv6) != 0;
+  changed_v6 = has_v6 && g_strcmp0 (self->tmp_addr, self->ipv6) != 0;
   if (changed_v6) {
     g_free (self->ipv6);
     self->ipv6 = g_strdup (self->tmp_addr);
@@ -304,6 +307,9 @@ on_watch_network (CallsNetworkWatch *self)
   if (changed_v4 || changed_v6)
     g_signal_emit (self, signals[NETWORK_CHANGED], 0);
 
+  if (has_v4 || has_v6)
+    g_signal_emit (self, signals[NETWORK_ROUTABLE], 0);
+
   return G_SOURCE_CONTINUE;
 }
 
@@ -360,6 +366,13 @@ calls_network_watch_class_init (CallsNetworkWatchClass *klass)
                                            NULL, NULL, NULL,
                                            G_TYPE_NONE,
                                            0);
+  signals[NETWORK_ROUTABLE] = g_signal_new ("network-routable",
+                                           CALLS_TYPE_NETWORK_WATCH,
+                                           G_SIGNAL_RUN_LAST,
+                                           0,
+                                           NULL, NULL, NULL,
+                                           G_TYPE_NONE,
+                                           0);
 
   props[PROP_IPV4] =
     g_param_spec_string ("ipv4",