From fe2aade56531991870832e2c83b8ccd9be17e221 Mon Sep 17 00:00:00 2001
From: Thomas Haller <thaller@redhat.com>
Date: Wed, 7 Jun 2023 08:51:54 +0200
Subject: [PATCH] ppp: fix plugin name for "rp-pppoe.so" with ppp 2.5

Between ppp 2.4.8 and 2.4.9, "rp-pppoe.so" was renamed to "pppoe.so" (and a
symlink created). Between 2.4.9 and 2.5.0, the symlink was dropped.

See-also: https://github.com/ppp-project/ppp/commit/b2c36e6c0e1655aea9b1b0a03a8160f42a26c884

I guess, NetworkManager always meant to use ppp's "(rp-)pppoe.so"
plugin, and never what rp-pppoe provides.

If a user actually wants to use the plugin from rp-pppoe project, then
this is going to break. But it seams, we usually intend to use the
plugin from the ppp project.

https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/issues/1312

Fixes: afe80171b24d ('ppp: move ppp code to "nm-pppd-compat.c"')
---
 src/core/ppp/nm-ppp-manager.c | 5 +++--
 src/core/ppp/nm-pppd-compat.c | 8 ++++++++
 src/core/ppp/nm-pppd-compat.h | 2 ++
 3 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/src/core/ppp/nm-ppp-manager.c b/src/core/ppp/nm-ppp-manager.c
index bb043a7e41..58364c384d 100644
--- a/src/core/ppp/nm-ppp-manager.c
+++ b/src/core/ppp/nm-ppp-manager.c
@@ -38,6 +38,7 @@
 #include "nm-pppd-plugin.h"
 #include "nm-ppp-plugin-api.h"
 #include "nm-ppp-status.h"
+#include "nm-pppd-compat.h"
 
 #define NM_PPPD_PLUGIN PPPD_PLUGIN_DIR "/nm-pppd-plugin.so"
 
@@ -843,7 +844,7 @@ create_pppd_cmd_line(NMPPPManager   *self,
         const char *pppoe_service;
 
         nm_strv_ptrarray_add_string_dup(cmd, "plugin");
-        nm_strv_ptrarray_add_string_dup(cmd, "rp-pppoe.so");
+        nm_strv_ptrarray_add_string_dup(cmd, nm_pppd_compat_get_pppoe_plugin_name());
 
         nm_strv_ptrarray_add_string_concat(cmd, "nic-", priv->parent_iface);
 
@@ -872,7 +873,7 @@ create_pppd_cmd_line(NMPPPManager   *self,
 
         } else if (!strcmp(protocol, NM_SETTING_ADSL_PROTOCOL_PPPOE)) {
             nm_strv_ptrarray_add_string_dup(cmd, "plugin");
-            nm_strv_ptrarray_add_string_dup(cmd, "rp-pppoe.so");
+            nm_strv_ptrarray_add_string_dup(cmd, nm_pppd_compat_get_pppoe_plugin_name());
             nm_strv_ptrarray_add_string_dup(cmd, priv->parent_iface);
         }
 
diff --git a/src/core/ppp/nm-pppd-compat.c b/src/core/ppp/nm-pppd-compat.c
index fd67eb3493..81b69f4663 100644
--- a/src/core/ppp/nm-pppd-compat.c
+++ b/src/core/ppp/nm-pppd-compat.c
@@ -94,6 +94,14 @@ G_STATIC_ASSERT(NM_PPPD_COMPAT_MAXSECRETLEN == MAXSECRETLEN);
 
 /*****************************************************************************/
 
+_nm_const const char *
+nm_pppd_compat_get_pppoe_plugin_name(void)
+{
+    return PPP_VERSION_2_5_OR_NEWER ? "pppoe.so" : "rp-pppoe.so";
+}
+
+/*****************************************************************************/
+
 int
 nm_pppd_compat_get_ifunit(void)
 {
diff --git a/src/core/ppp/nm-pppd-compat.h b/src/core/ppp/nm-pppd-compat.h
index 11376e360e..1edffdfa98 100644
--- a/src/core/ppp/nm-pppd-compat.h
+++ b/src/core/ppp/nm-pppd-compat.h
@@ -11,6 +11,8 @@
 
 int nm_pppd_compat_get_ifunit(void);
 
+const char *nm_pppd_compat_get_pppoe_plugin_name(void) _nm_const;
+
 const char *nm_pppd_compat_get_ifname(void);
 void        nm_pppd_compat_set_ifname(const char *ifname);