libmbim-glib,net-port-manager: refactor netlink implementation to new files

In preparation for wwan support.

5 files changed, 441 insertions, 312 deletions

diff --git a/docs/reference/libmbim-glib/meson.build b/docs/reference/libmbim-glib/meson.build
index 3dcc67e..29c6adc 100644
--- a/docs/reference/libmbim-glib/meson.build
+++ b/docs/reference/libmbim-glib/meson.build
@@ -12,6 +12,7 @@ src_dirs = [
 
 private_headers = [
   'mbim-helpers.h',
+  'mbim-helpers-netlink.h',
   'mbim-message-private.h',
   'mbim-net-port-manager.h',
 ]
diff --git a/src/libmbim-glib/mbim-helpers-netlink.c b/src/libmbim-glib/mbim-helpers-netlink.c
new file mode 100644
index 0000000..9a14086
--- /dev/null
+++ b/src/libmbim-glib/mbim-helpers-netlink.c
@@ -0,0 +1,298 @@
+/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * libmbim-glib -- GLib/GIO based library to control MBIM devices
+ *
+ * Copyright (C) 2022 Daniele Palmas <dnlplm@gmail.com>
+ *
+ * Based on previous work:
+ *   Copyright (C) 2020-2021 Eric Caruso <ejcaruso@chromium.org>
+ *   Copyright (C) 2020-2021 Andrew Lassalle <andrewlassalle@chromium.org>
+ *   Copyright (C) 2021 Aleksander Morgado <aleksander@aleksander.es>
+ */
+
+#include <linux/if_link.h>
+#include <linux/netlink.h>
+#include <linux/rtnetlink.h>
+#include <sys/socket.h>
+
+#include "mbim-helpers-netlink.h"
+
+/*****************************************************************************/
+/*
+ * Netlink message construction functions
+ */
+
+NetlinkHeader *
+mbim_helpers_netlink_get_message_header (NetlinkMessage *msg)
+{
+    return (NetlinkHeader *) (msg->data);
+}
+
+guint
+mbim_helpers_netlink_get_pos_of_next_attr (NetlinkMessage *msg)
+{
+    return NLMSG_ALIGN (msg->len);
+}
+
+static void
+append_netlink_attribute (NetlinkMessage *msg,
+                          gushort         type,
+                          gconstpointer   value,
+                          gushort         len)
+{
+    guint          attr_len;
+    guint          old_len;
+    guint          next_attr_rel_pos;
+    char          *next_attr_abs_pos;
+    struct rtattr  new_attr;
+
+    /* Expand the buffer to hold the new attribute */
+    attr_len = RTA_ALIGN (RTA_LENGTH (len));
+    old_len = msg->len;
+    next_attr_rel_pos = mbim_helpers_netlink_get_pos_of_next_attr (msg);
+
+    g_byte_array_set_size (msg, next_attr_rel_pos + attr_len);
+    /* fill new bytes with zero, since some padding is added between attributes. */
+    memset ((char *) msg->data + old_len, 0, msg->len - old_len);
+
+    new_attr.rta_type = type;
+    new_attr.rta_len = RTA_LENGTH (len);
+    next_attr_abs_pos = (char *) msg->data + next_attr_rel_pos;
+    memcpy (next_attr_abs_pos, &new_attr, sizeof (struct rtattr));
+
+    if (value)
+        memcpy (RTA_DATA (next_attr_abs_pos), value, len);
+
+    /* Update the total netlink message length */
+    mbim_helpers_netlink_get_message_header (msg)->msghdr.nlmsg_len = msg->len;
+}
+
+void
+mbim_helpers_netlink_append_attribute_nested (NetlinkMessage *msg,
+                                              gushort         type)
+{
+    append_netlink_attribute (msg, type, NULL, 0);
+}
+
+void
+mbim_helpers_netlink_append_attribute_string (NetlinkMessage *msg,
+                                              gushort         type,
+                                              const gchar    *value)
+{
+    append_netlink_attribute (msg, type, value, strlen (value));
+}
+
+void
+mbim_helpers_netlink_append_attribute_uint16 (NetlinkMessage *msg,
+                                              gushort         type,
+                                              guint16         value)
+{
+    append_netlink_attribute (msg, type, &value, sizeof (value));
+}
+
+void
+mbim_helpers_netlink_append_attribute_uint32 (NetlinkMessage *msg,
+                                              gushort         type,
+                                              guint32         value)
+{
+    append_netlink_attribute (msg, type, &value, sizeof (value));
+}
+
+NetlinkMessage *
+mbim_helpers_netlink_message_new (guint16 type,
+                                  guint16 extra_flags)
+{
+    NetlinkMessage *msg;
+    NetlinkHeader  *hdr;
+
+    int size = sizeof (NetlinkHeader);
+
+    msg = g_byte_array_new ();
+    g_byte_array_set_size (msg, size);
+    memset ((char *) msg->data, 0, size);
+
+    hdr = mbim_helpers_netlink_get_message_header (msg);
+    hdr->msghdr.nlmsg_len = msg->len;
+    hdr->msghdr.nlmsg_type = type;
+    hdr->msghdr.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK | extra_flags;
+    hdr->ifreq.ifi_family = AF_UNSPEC;
+    return msg;
+}
+
+void
+mbim_helpers_netlink_message_free (NetlinkMessage *msg)
+{
+    g_byte_array_unref (msg);
+}
+
+/*****************************************************************************/
+/*
+ * Transaction management functions
+ */
+
+static gboolean
+transaction_timed_out (NetlinkTransaction *tr,
+                       GHashTable         *transactions)
+{
+    GTask   *task;
+    guint32  sequence_id;
+
+    task = g_steal_pointer (&tr->completion_task);
+    sequence_id = tr->sequence_id;
+
+    g_hash_table_remove (transactions,
+                         GUINT_TO_POINTER (tr->sequence_id));
+
+    g_task_return_new_error (task,
+                             G_IO_ERROR,
+                             G_IO_ERROR_TIMED_OUT,
+                             "Netlink message with sequence ID %u timed out",
+                             sequence_id);
+
+    g_object_unref (task);
+    return G_SOURCE_REMOVE;
+}
+
+void
+mbim_helpers_netlink_transaction_complete_with_error (NetlinkTransaction *tr,
+                                                      GHashTable         *transactions,
+                                                      GError             *error)
+{
+    GTask *task;
+
+    task = g_steal_pointer (&tr->completion_task);
+
+    g_hash_table_remove (transactions,
+                         GUINT_TO_POINTER (tr->sequence_id));
+
+    g_task_return_error (task, error);
+    g_object_unref (task);
+}
+
+void
+mbim_helpers_netlink_transaction_complete (NetlinkTransaction *tr,
+                                           GHashTable         *transactions,
+                                           gint                saved_errno)
+{
+    GTask   *task;
+    guint32  sequence_id;
+
+    task = g_steal_pointer (&tr->completion_task);
+    sequence_id = tr->sequence_id;
+
+    g_hash_table_remove (transactions,
+                         GUINT_TO_POINTER (tr->sequence_id));
+
+    if (!saved_errno) {
+        g_task_return_boolean (task, TRUE);
+    } else {
+        g_task_return_new_error (task,
+                                 G_IO_ERROR,
+                                 g_io_error_from_errno (saved_errno),
+                                 "Netlink message with transaction %u failed: %s",
+                                 sequence_id,
+                                 g_strerror (saved_errno));
+    }
+
+    g_object_unref (task);
+}
+
+void
+mbim_helpers_netlink_transaction_free (NetlinkTransaction *tr)
+{
+    g_assert (tr->completion_task == NULL);
+    g_source_destroy (tr->timeout_source);
+    g_source_unref (tr->timeout_source);
+    g_slice_free (NetlinkTransaction, tr);
+}
+
+NetlinkTransaction *
+mbim_helpers_netlink_transaction_new (guint          *sequence_id,
+                                      GHashTable     *transactions,
+                                      NetlinkMessage *msg,
+                                      guint           timeout,
+                                      GTask          *task)
+{
+    NetlinkTransaction *tr;
+
+    tr = g_slice_new0 (NetlinkTransaction);
+    tr->sequence_id = ++(*sequence_id);
+    mbim_helpers_netlink_get_message_header (msg)->msghdr.nlmsg_seq = tr->sequence_id;
+    if (timeout) {
+        tr->timeout_source = g_timeout_source_new_seconds (timeout);
+        g_source_set_callback (tr->timeout_source,
+                               (GSourceFunc) transaction_timed_out,
+                               tr,
+                               NULL);
+        g_source_attach (tr->timeout_source,
+                         g_main_context_get_thread_default ());
+    }
+    tr->completion_task = g_object_ref (task);
+
+    g_hash_table_insert (transactions,
+                         GUINT_TO_POINTER (tr->sequence_id),
+                         tr);
+    return tr;
+}
+
+/*****************************************************************************/
+
+static gboolean
+netlink_message_cb (GSocket      *socket,
+                    GIOCondition  condition,
+                    GHashTable   *transactions)
+{
+    GError          *error = NULL;
+    gchar            buf[512];
+    int              bytes_received;
+    unsigned int     buffer_len;
+    struct nlmsghdr *hdr;
+
+    if (condition & G_IO_HUP || condition & G_IO_ERR) {
+        g_warning ("[netlink] socket connection closed.");
+        return G_SOURCE_REMOVE;
+    }
+
+    bytes_received = g_socket_receive (socket, buf, sizeof (buf), NULL, &error);
+
+    if (bytes_received < 0) {
+        g_warning ("[netlink] socket i/o failure: %s", error->message);
+        g_error_free (error);
+        return G_SOURCE_REMOVE;
+    }
+
+    buffer_len = (unsigned int ) bytes_received;
+    for (hdr = (struct nlmsghdr *) buf; NLMSG_OK (hdr, buffer_len);
+         NLMSG_NEXT (hdr, buffer_len)) {
+        NetlinkTransaction *tr;
+        struct nlmsgerr    *err;
+
+        if (hdr->nlmsg_type != NLMSG_ERROR)
+            continue;
+
+        tr = g_hash_table_lookup (transactions,
+                                  GUINT_TO_POINTER (hdr->nlmsg_seq));
+        if (!tr)
+            continue;
+
+        err = NLMSG_DATA (buf);
+        mbim_helpers_netlink_transaction_complete (tr, transactions, err->error);
+    }
+    return G_SOURCE_CONTINUE;
+}
+
+void
+mbim_helpers_netlink_set_callback (GSource    **source,
+                                   GSocket     *socket,
+                                   GHashTable  *transactions)
+{
+    *source = g_socket_create_source (socket,
+                                      G_IO_IN | G_IO_ERR | G_IO_HUP,
+                                      NULL);
+    g_source_set_callback (*source,
+                           (GSourceFunc) netlink_message_cb,
+                           transactions,
+                           NULL);
+    g_source_attach (*source, g_main_context_get_thread_default ());
+}
diff --git a/src/libmbim-glib/mbim-helpers-netlink.h b/src/libmbim-glib/mbim-helpers-netlink.h
new file mode 100644
index 0000000..3c73b32
--- /dev/null
+++ b/src/libmbim-glib/mbim-helpers-netlink.h
@@ -0,0 +1,98 @@
+/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * libmbim-glib -- GLib/GIO based library to control MBIM devices
+ *
+ * Copyright (C) 2022 Daniele Palmas <dnlplm@gmail.com>
+ *
+ * Based on previous work:
+ *   Copyright (C) 2020-2021 Eric Caruso <ejcaruso@chromium.org>
+ *   Copyright (C) 2020-2021 Andrew Lassalle <andrewlassalle@chromium.org>
+ *   Copyright (C) 2021 Aleksander Morgado <aleksander@aleksander.es>
+ */
+
+#ifndef _LIBMBIM_GLIB_MBIM_HELPERS_NETLINK_H_
+#define _LIBMBIM_GLIB_MBIM_HELPERS_NETLINK_H_
+
+#if !defined (LIBMBIM_GLIB_COMPILATION)
+#error "This is a private header!!"
+#endif
+
+#include <glib.h>
+#include <gio/gio.h>
+
+G_BEGIN_DECLS
+
+typedef GByteArray NetlinkMessage;
+
+typedef struct {
+    struct nlmsghdr  msghdr;
+    struct ifinfomsg ifreq;
+} NetlinkHeader;
+
+G_GNUC_INTERNAL
+NetlinkHeader *mbim_helpers_netlink_get_message_header (NetlinkMessage *msg);
+
+G_GNUC_INTERNAL
+guint mbim_helpers_netlink_get_pos_of_next_attr (NetlinkMessage *msg);
+
+G_GNUC_INTERNAL
+void mbim_helpers_netlink_append_attribute_nested (NetlinkMessage *msg,
+                                                   gushort         type);
+
+G_GNUC_INTERNAL
+void mbim_helpers_netlink_append_attribute_string (NetlinkMessage *msg,
+                                                   gushort         type,
+                                                   const gchar    *value);
+
+G_GNUC_INTERNAL
+void mbim_helpers_netlink_append_attribute_uint16 (NetlinkMessage *msg,
+                                                   gushort         type,
+                                                   guint16         value);
+
+G_GNUC_INTERNAL
+void mbim_helpers_netlink_append_attribute_uint32 (NetlinkMessage *msg,
+                                                   gushort         type,
+                                                   guint32         value);
+
+G_GNUC_INTERNAL
+NetlinkMessage *mbim_helpers_netlink_message_new (guint16 type,
+                                                  guint16 extra_flags);
+
+G_GNUC_INTERNAL
+void mbim_helpers_netlink_message_free (NetlinkMessage *msg);
+
+typedef struct {
+    guint32  sequence_id;
+    GSource *timeout_source;
+    GTask   *completion_task;
+} NetlinkTransaction;
+
+G_GNUC_INTERNAL
+void mbim_helpers_netlink_transaction_complete_with_error (NetlinkTransaction *tr,
+                                                           GHashTable         *transactions,
+                                                           GError             *error);
+
+G_GNUC_INTERNAL
+void mbim_helpers_netlink_transaction_complete (NetlinkTransaction *tr,
+                                                GHashTable         *transactions,
+                                                gint                saved_errno);
+
+G_GNUC_INTERNAL
+void mbim_helpers_netlink_transaction_free (NetlinkTransaction *tr);
+
+G_GNUC_INTERNAL
+NetlinkTransaction *mbim_helpers_netlink_transaction_new (guint          *sequence_id,
+                                                          GHashTable     *transactions,
+                                                          NetlinkMessage *msg,
+                                                          guint           timeout,
+                                                          GTask          *task);
+
+G_GNUC_INTERNAL
+void mbim_helpers_netlink_set_callback (GSource    **source,
+                                        GSocket     *socket,
+                                        GHashTable  *transactions);
+
+G_END_DECLS
+
+#endif /* _LIBMBIM_GLIB_MBIM_HELPERS_NETLINK_H_ */
diff --git a/src/libmbim-glib/mbim-net-port-manager.c b/src/libmbim-glib/mbim-net-port-manager.c
index 032ed3f..5958660 100644
--- a/src/libmbim-glib/mbim-net-port-manager.c
+++ b/src/libmbim-glib/mbim-net-port-manager.c
@@ -23,6 +23,7 @@
 #include "mbim-helpers.h"
 #include "mbim-error-types.h"
 #include "mbim-net-port-manager.h"
+#include "mbim-helpers-netlink.h"
 
 G_DEFINE_TYPE (MbimNetPortManager, mbim_net_port_manager, G_TYPE_OBJECT)
 
@@ -55,232 +56,6 @@ session_id_to_ifname (const gchar *ifname_prefix,
 }
 
 /*****************************************************************************/
-/*
- * Netlink message construction functions
- */
-
-typedef GByteArray NetlinkMessage;
-
-typedef struct {
-    struct nlmsghdr  msghdr;
-    struct ifinfomsg ifreq;
-} NetlinkHeader;
-
-static NetlinkHeader *
-netlink_message_header (NetlinkMessage *msg)
-{
-    return (NetlinkHeader *) (msg->data);
-}
-
-static guint
-get_pos_of_next_attr (NetlinkMessage *msg)
-{
-    return NLMSG_ALIGN (msg->len);
-}
-
-static void
-append_netlink_attribute (NetlinkMessage *msg,
-                          gushort         type,
-                          gconstpointer   value,
-                          gushort         len)
-{
-    guint          attr_len;
-    guint          old_len;
-    guint          next_attr_rel_pos;
-    char          *next_attr_abs_pos;
-    struct rtattr  new_attr;
-
-    /* Expand the buffer to hold the new attribute */
-    attr_len = RTA_ALIGN (RTA_LENGTH (len));
-    old_len = msg->len;
-    next_attr_rel_pos = get_pos_of_next_attr (msg);
-
-    g_byte_array_set_size (msg, next_attr_rel_pos + attr_len);
-    /* fill new bytes with zero, since some padding is added between attributes. */
-    memset ((char *) msg->data + old_len, 0, msg->len - old_len);
-
-    new_attr.rta_type = type;
-    new_attr.rta_len = RTA_LENGTH (len);
-    next_attr_abs_pos = (char *) msg->data + next_attr_rel_pos;
-    memcpy (next_attr_abs_pos, &new_attr, sizeof (struct rtattr));
-
-    if (value)
-        memcpy (RTA_DATA (next_attr_abs_pos), value, len);
-
-    /* Update the total netlink message length */
-    netlink_message_header (msg)->msghdr.nlmsg_len = msg->len;
-}
-
-static void
-append_netlink_attribute_nested (NetlinkMessage *msg,
-                                 gushort         type)
-{
-    append_netlink_attribute (msg, type, NULL, 0);
-}
-
-static void
-append_netlink_attribute_string (NetlinkMessage *msg,
-                                 gushort         type,
-                                 const gchar    *value)
-{
-    append_netlink_attribute (msg, type, value, strlen (value));
-}
-
-static void
-append_netlink_attribute_uint16 (NetlinkMessage *msg,
-                                 gushort         type,
-                                 guint16         value)
-{
-    append_netlink_attribute (msg, type, &value, sizeof (value));
-}
-
-static void
-append_netlink_attribute_uint32 (NetlinkMessage *msg,
-                                 gushort         type,
-                                 guint32         value)
-{
-    append_netlink_attribute (msg, type, &value, sizeof (value));
-}
-
-static NetlinkMessage *
-netlink_message_new (guint16 type,
-                     guint16 extra_flags)
-{
-    NetlinkMessage *msg;
-    NetlinkHeader  *hdr;
-
-    int size = sizeof (NetlinkHeader);
-
-    msg = g_byte_array_new ();
-    g_byte_array_set_size (msg, size);
-    memset ((char *) msg->data, 0, size);
-
-    hdr = netlink_message_header (msg);
-    hdr->msghdr.nlmsg_len = msg->len;
-    hdr->msghdr.nlmsg_type = type;
-    hdr->msghdr.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK | extra_flags;
-    hdr->ifreq.ifi_family = AF_UNSPEC;
-    return msg;
-}
-
-static void
-netlink_message_free (NetlinkMessage *msg)
-{
-    g_byte_array_unref (msg);
-}
-
-/*****************************************************************************/
-
-typedef struct {
-    MbimNetPortManager *manager;
-    guint32             sequence_id;
-    GSource            *timeout_source;
-    GTask              *completion_task;
-} Transaction;
-
-static gboolean
-transaction_timed_out (Transaction *tr)
-{
-    GTask *task;
-    guint32 sequence_id;
-
-    task = g_steal_pointer (&tr->completion_task);
-    sequence_id = tr->sequence_id;
-
-    g_hash_table_remove (tr->manager->priv->transactions,
-                         GUINT_TO_POINTER (tr->sequence_id));
-
-    g_task_return_new_error (task,
-                             G_IO_ERROR,
-                             G_IO_ERROR_TIMED_OUT,
-                             "Netlink message with sequence ID %u timed out",
-                             sequence_id);
-
-    g_object_unref (task);
-    return G_SOURCE_REMOVE;
-}
-
-static void
-transaction_complete_with_error (Transaction *tr,
-                                 GError      *error)
-{
-    GTask *task;
-
-    task = g_steal_pointer (&tr->completion_task);
-
-    g_hash_table_remove (tr->manager->priv->transactions,
-                         GUINT_TO_POINTER (tr->sequence_id));
-
-    g_task_return_error (task, error);
-    g_object_unref (task);
-}
-
-static void
-transaction_complete (Transaction *tr,
-                      gint         saved_errno)
-{
-    GTask *task;
-    guint32 sequence_id;
-
-    task = g_steal_pointer (&tr->completion_task);
-    sequence_id = tr->sequence_id;
-
-    g_hash_table_remove (tr->manager->priv->transactions,
-                         GUINT_TO_POINTER (tr->sequence_id));
-
-    if (!saved_errno) {
-        g_task_return_boolean (task, TRUE);
-    } else {
-        g_task_return_new_error (task,
-                                 G_IO_ERROR,
-                                 g_io_error_from_errno (saved_errno),
-                                 "Netlink message with transaction %u failed: %s",
-                                 sequence_id,
-                                 g_strerror (saved_errno));
-    }
-
-    g_object_unref (task);
-}
-
-static void
-transaction_free (Transaction *tr)
-{
-    g_assert (tr->completion_task == NULL);
-    g_source_destroy (tr->timeout_source);
-    g_source_unref (tr->timeout_source);
-    g_slice_free (Transaction, tr);
-}
-
-static Transaction *
-transaction_new (MbimNetPortManager *manager,
-                 NetlinkMessage         *msg,
-                 guint                   timeout,
-                 GTask                  *task)
-{
-    Transaction *tr;
-
-    tr = g_slice_new0 (Transaction);
-    tr->manager = manager;
-    tr->sequence_id = ++manager->priv->current_sequence_id;
-    netlink_message_header (msg)->msghdr.nlmsg_seq = tr->sequence_id;
-    if (timeout) {
-        tr->timeout_source = g_timeout_source_new_seconds (timeout);
-        g_source_set_callback (tr->timeout_source,
-                               (GSourceFunc) transaction_timed_out,
-                               tr,
-                               NULL);
-        g_source_attach (tr->timeout_source,
-                         g_main_context_get_thread_default ());
-    }
-    tr->completion_task = g_object_ref (task);
-
-    g_hash_table_insert (manager->priv->transactions,
-                         GUINT_TO_POINTER (tr->sequence_id),
-                         tr);
-    return tr;
-}
-
-/*****************************************************************************/
 
 static guint
 session_id_to_vlan_id (guint session_id)
@@ -302,19 +77,19 @@ netlink_message_new_link (guint  vlan_id,
     guint           linkinfo_pos, datainfo_pos;
     struct rtattr   info;
 
-    msg = netlink_message_new (RTM_NEWLINK, NLM_F_CREATE | NLM_F_EXCL);
-    append_netlink_attribute_uint32 (msg, IFLA_LINK, base_if_index);
-    append_netlink_attribute_string (msg, IFLA_IFNAME, ifname);
+    msg = mbim_helpers_netlink_message_new (RTM_NEWLINK, NLM_F_CREATE | NLM_F_EXCL);
+    mbim_helpers_netlink_append_attribute_uint32 (msg, IFLA_LINK, base_if_index);
+    mbim_helpers_netlink_append_attribute_string (msg, IFLA_IFNAME, ifname);
 
     /* Store the position of the next attribute to adjust its length later. */
-    linkinfo_pos = get_pos_of_next_attr (msg);
-    append_netlink_attribute_nested (msg, IFLA_LINKINFO);
-    append_netlink_attribute_string (msg, IFLA_INFO_KIND, VLAN_DATA_TYPE);
+    linkinfo_pos = mbim_helpers_netlink_get_pos_of_next_attr (msg);
+    mbim_helpers_netlink_append_attribute_nested (msg, IFLA_LINKINFO);
+    mbim_helpers_netlink_append_attribute_string (msg, IFLA_INFO_KIND, VLAN_DATA_TYPE);
 
     /* Store the position of the next attribute to adjust its length later. */
-    datainfo_pos = get_pos_of_next_attr (msg);
-    append_netlink_attribute_nested (msg, IFLA_INFO_DATA);
-    append_netlink_attribute_uint16 (msg, IFLA_VLAN_ID, vlan_id);
+    datainfo_pos = mbim_helpers_netlink_get_pos_of_next_attr (msg);
+    mbim_helpers_netlink_append_attribute_nested (msg, IFLA_INFO_DATA);
+    mbim_helpers_netlink_append_attribute_uint16 (msg, IFLA_VLAN_ID, vlan_id);
 
     /* Use memcpy to preserve byte alignment */
     memcpy (&info, (char *) msg->data + datainfo_pos, sizeof (struct rtattr));
@@ -335,8 +110,8 @@ netlink_message_del_link (guint ifindex)
 
     g_assert (ifindex != 0);
 
-    msg = netlink_message_new (RTM_DELLINK, 0);
-    netlink_message_header (msg)->ifreq.ifi_index = ifindex;
+    msg = mbim_helpers_netlink_message_new (RTM_DELLINK, 0);
+    mbim_helpers_netlink_get_message_header (msg)->ifreq.ifi_index = ifindex;
 
     return msg;
 }
@@ -344,52 +119,6 @@ netlink_message_del_link (guint ifindex)
 /*****************************************************************************/
 
 static gboolean
-netlink_message_cb (GSocket                *socket,
-                    GIOCondition            condition,
-                    MbimNetPortManager *self)
-{
-    GError          *error = NULL;
-    gchar            buf[512];
-    int              bytes_received;
-    unsigned int     buffer_len;
-    struct nlmsghdr *hdr;
-
-    if (condition & G_IO_HUP || condition & G_IO_ERR) {
-        g_warning ("[netlink] socket connection closed.");
-        return G_SOURCE_REMOVE;
-    }
-
-    bytes_received = g_socket_receive (socket, buf, sizeof (buf), NULL, &error);
-
-    if (bytes_received < 0) {
-        g_warning ("[netlink] socket i/o failure: %s", error->message);
-        g_error_free (error);
-        return G_SOURCE_REMOVE;
-    }
-
-    buffer_len = (unsigned int ) bytes_received;
-    for (hdr = (struct nlmsghdr *) buf; NLMSG_OK (hdr, buffer_len);
-         NLMSG_NEXT (hdr, buffer_len)) {
-        Transaction     *tr;
-        struct nlmsgerr *err;
-
-        if (hdr->nlmsg_type != NLMSG_ERROR)
-            continue;
-
-        tr = g_hash_table_lookup (self->priv->transactions,
-                                  GUINT_TO_POINTER (hdr->nlmsg_seq));
-        if (!tr)
-            continue;
-
-        err = NLMSG_DATA (buf);
-        transaction_complete (tr, err->error);
-    }
-    return G_SOURCE_CONTINUE;
-}
-
-/*****************************************************************************/
-
-static gboolean
 get_first_free_session_id (MbimNetPortManager *self,
                            const gchar        *ifname_prefix,
                            guint              *session_id)
@@ -457,13 +186,13 @@ mbim_net_port_manager_add_link (MbimNetPortManager  *self,
                                 GAsyncReadyCallback  callback,
                                 gpointer             user_data)
 {
-    NetlinkMessage *msg;
-    Transaction    *tr;
-    GTask          *task;
-    GError         *error = NULL;
-    gssize          bytes_sent;
-    guint           base_if_index;
-    AddLinkContext *ctx;
+    NetlinkMessage     *msg;
+    NetlinkTransaction *tr;
+    GTask              *task;
+    GError             *error = NULL;
+    gssize              bytes_sent;
+    guint               base_if_index;
+    AddLinkContext     *ctx;
 
     task = g_task_new (self, cancellable, callback, user_data);
 
@@ -507,17 +236,21 @@ mbim_net_port_manager_add_link (MbimNetPortManager  *self,
     msg = netlink_message_new_link (ctx->vlan_id, ctx->ifname, base_if_index);
 
     /* The task ownership is transferred to the transaction. */
-    tr = transaction_new (self, msg, timeout, task);
+    tr = mbim_helpers_netlink_transaction_new (&self->priv->current_sequence_id,
+                                               self->priv->transactions,
+                                               msg,
+                                               timeout,
+                                               task);
 
     bytes_sent = g_socket_send (self->priv->socket,
                                 (const gchar *) msg->data,
                                 msg->len,
                                 cancellable,
                                 &error);
-    netlink_message_free (msg);
+    mbim_helpers_netlink_message_free (msg);
 
     if (bytes_sent < 0)
-        transaction_complete_with_error (tr, error);
+        mbim_helpers_netlink_transaction_complete_with_error (tr, self->priv->transactions, error);
 
     g_object_unref (task);
 }
@@ -538,12 +271,12 @@ mbim_net_port_manager_del_link (MbimNetPortManager  *self,
                                 GAsyncReadyCallback  callback,
                                 gpointer             user_data)
 {
-    guint           ifindex;
-    NetlinkMessage *msg;
-    Transaction    *tr;
-    GTask          *task;
-    GError         *error = NULL;
-    gssize          bytes_sent;
+    guint               ifindex;
+    NetlinkMessage     *msg;
+    NetlinkTransaction *tr;
+    GTask              *task;
+    GError             *error = NULL;
+    gssize              bytes_sent;
 
     task = g_task_new (self, cancellable, callback, user_data);
 
@@ -558,17 +291,21 @@ mbim_net_port_manager_del_link (MbimNetPortManager  *self,
 
     msg = netlink_message_del_link (ifindex);
     /* The task ownership is transferred to the transaction. */
-    tr = transaction_new (self, msg, timeout, task);
+    tr = mbim_helpers_netlink_transaction_new (&self->priv->current_sequence_id,
+                                               self->priv->transactions,
+                                               msg,
+                                               timeout,
+                                               task);
 
     bytes_sent = g_socket_send (self->priv->socket,
                                 (const gchar *) msg->data,
                                 msg->len,
                                 cancellable,
                                 &error);
-    netlink_message_free (msg);
+    mbim_helpers_netlink_message_free (msg);
 
     if (bytes_sent < 0)
-        transaction_complete_with_error (tr, error);
+        mbim_helpers_netlink_transaction_complete_with_error (tr, self->priv->transactions, error);
 
     g_object_unref (task);
 }
@@ -710,21 +447,15 @@ mbim_net_port_manager_new (const gchar  *iface,
     self = g_object_new (MBIM_TYPE_NET_PORT_MANAGER, NULL);
     self->priv->iface = g_strdup (iface);
     self->priv->socket = gsocket;
-    self->priv->source = g_socket_create_source (self->priv->socket,
-                                                 G_IO_IN | G_IO_ERR | G_IO_HUP,
-                                                 NULL);
-    g_source_set_callback (self->priv->source,
-                           (GSourceFunc) netlink_message_cb,
-                           self,
-                           NULL);
-    g_source_attach (self->priv->source, g_main_context_get_thread_default ());
-
     self->priv->current_sequence_id = 0;
     self->priv->transactions =
         g_hash_table_new_full (g_direct_hash,
                                g_direct_equal,
                                NULL,
-                               (GDestroyNotify) transaction_free);
+                               (GDestroyNotify) mbim_helpers_netlink_transaction_free);
+    mbim_helpers_netlink_set_callback (&self->priv->source,
+                                       self->priv->socket,
+                                       self->priv->transactions);
 
     return self;
 }
diff --git a/src/libmbim-glib/meson.build b/src/libmbim-glib/meson.build
index dee6368..a182866 100644
--- a/src/libmbim-glib/meson.build
+++ b/src/libmbim-glib/meson.build
@@ -39,6 +39,7 @@ sources = files(
   'mbim-compat.c',
   'mbim-device.c',
   'mbim-helpers.c',
+  'mbim-helpers-netlink.c',
   'mbim-message.c',
   'mbim-net-port-manager.c',
   'mbim-proxy.c',