Merge branch 'debian/master' into ubuntu/master

1 files changed, 857 insertions, 0 deletions

diff --git a/src/core/devices/bluetooth/nm-bluez5-dun.c b/src/core/devices/bluetooth/nm-bluez5-dun.c
new file mode 100644
index 00000000..e29884d8
--- /dev/null
+++ b/src/core/devices/bluetooth/nm-bluez5-dun.c
@@ -0,0 +1,857 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2014 Red Hat, Inc.
+ */
+
+#include "src/core/nm-default-daemon.h"
+
+#include <sys/socket.h>
+#include <bluetooth/sdp.h>
+#include <bluetooth/sdp_lib.h>
+#include <bluetooth/rfcomm.h>
+#include <net/ethernet.h>
+#include <sys/ioctl.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+#include "nm-bluez5-dun.h"
+#include "nm-bt-error.h"
+#include "NetworkManagerUtils.h"
+
+#define RFCOMM_FMT "/dev/rfcomm%d"
+
+/*****************************************************************************/
+
+typedef struct {
+    GCancellable *       cancellable;
+    NMBluez5DunConnectCb callback;
+    gpointer             callback_user_data;
+
+    sdp_session_t *sdp_session;
+
+    GError *rfcomm_sdp_search_error;
+
+    GSource *source;
+
+    gint64 connect_open_tty_started_at;
+
+    gulong cancelled_id;
+
+    guint8 sdp_session_try_count;
+} ConnectData;
+
+struct _NMBluez5DunContext {
+    const char *dst_str;
+
+    ConnectData *cdat;
+
+    NMBluez5DunNotifyTtyHangupCb notify_tty_hangup_cb;
+    gpointer                     notify_tty_hangup_user_data;
+
+    char *rfcomm_tty_path;
+
+    GSource *rfcomm_tty_poll_source;
+
+    int rfcomm_sock_fd;
+    int rfcomm_tty_fd;
+    int rfcomm_tty_no;
+    int rfcomm_channel;
+
+    bdaddr_t src;
+    bdaddr_t dst;
+
+    char src_str[];
+};
+
+/*****************************************************************************/
+
+#define _NMLOG_DOMAIN      LOGD_BT
+#define _NMLOG_PREFIX_NAME "bluez"
+#define _NMLOG(level, context, ...)                                       \
+    G_STMT_START                                                          \
+    {                                                                     \
+        if (nm_logging_enabled((level), (_NMLOG_DOMAIN))) {               \
+            const NMBluez5DunContext *const _context = (context);         \
+                                                                          \
+            _nm_log((level),                                              \
+                    (_NMLOG_DOMAIN),                                      \
+                    0,                                                    \
+                    NULL,                                                 \
+                    NULL,                                                 \
+                    "%s: DUN[%s] " _NM_UTILS_MACRO_FIRST(__VA_ARGS__),    \
+                    _NMLOG_PREFIX_NAME,                                   \
+                    _context->src_str _NM_UTILS_MACRO_REST(__VA_ARGS__)); \
+        }                                                                 \
+    }                                                                     \
+    G_STMT_END
+
+/*****************************************************************************/
+
+static void     _context_invoke_callback_success(NMBluez5DunContext *context);
+static void     _context_invoke_callback_fail_and_free(NMBluez5DunContext *context, GError *error);
+static void     _context_free(NMBluez5DunContext *context);
+static int      _connect_open_tty(NMBluez5DunContext *context);
+static gboolean _connect_sdp_session_start(NMBluez5DunContext *context, GError **error);
+
+/*****************************************************************************/
+
+NM_AUTO_DEFINE_FCN0(NMBluez5DunContext *, _nm_auto_free_context, _context_free);
+#define nm_auto_free_context nm_auto(_nm_auto_free_context)
+
+/*****************************************************************************/
+
+const char *
+nm_bluez5_dun_context_get_adapter(const NMBluez5DunContext *context)
+{
+    return context->src_str;
+}
+
+const char *
+nm_bluez5_dun_context_get_remote(const NMBluez5DunContext *context)
+{
+    return context->dst_str;
+}
+
+const char *
+nm_bluez5_dun_context_get_rfcomm_dev(const NMBluez5DunContext *context)
+{
+    return context->rfcomm_tty_path;
+}
+
+/*****************************************************************************/
+
+static gboolean
+_rfcomm_tty_poll_cb(int fd, GIOCondition condition, gpointer user_data)
+{
+    NMBluez5DunContext *context = user_data;
+
+    _LOGD(context,
+          "receive %s%s%s signal on rfcomm file descriptor",
+          NM_FLAGS_HAS(condition, G_IO_ERR) ? "ERR" : "",
+          NM_FLAGS_ALL(condition, G_IO_HUP | G_IO_ERR) ? "," : "",
+          NM_FLAGS_HAS(condition, G_IO_HUP) ? "HUP" : "");
+
+    nm_clear_g_source_inst(&context->rfcomm_tty_poll_source);
+    context->notify_tty_hangup_cb(context, context->notify_tty_hangup_user_data);
+    return G_SOURCE_REMOVE;
+}
+
+static gboolean
+_connect_open_tty_retry_cb(gpointer user_data)
+{
+    NMBluez5DunContext *context = user_data;
+    int                 r;
+
+    r = _connect_open_tty(context);
+    if (r >= 0)
+        return G_SOURCE_REMOVE;
+
+    if (nm_utils_get_monotonic_timestamp_nsec()
+        > context->cdat->connect_open_tty_started_at + (30 * 100 * NM_UTILS_NSEC_PER_MSEC)) {
+        gs_free_error GError *error = NULL;
+
+        nm_clear_g_source_inst(&context->cdat->source);
+        g_set_error(&error,
+                    NM_BT_ERROR,
+                    NM_BT_ERROR_DUN_CONNECT_FAILED,
+                    "give up waiting to open %s device: %s (%d)",
+                    context->rfcomm_tty_path,
+                    nm_strerror_native(r),
+                    -r);
+        _context_invoke_callback_fail_and_free(context, error);
+        return G_SOURCE_REMOVE;
+    }
+
+    return G_SOURCE_CONTINUE;
+}
+
+static int
+_connect_open_tty(NMBluez5DunContext *context)
+{
+    int fd;
+    int errsv;
+
+    fd = open(context->rfcomm_tty_path, O_RDONLY | O_NOCTTY | O_CLOEXEC);
+    if (fd < 0) {
+        errsv = NM_ERRNO_NATIVE(errno);
+
+        if (!context->cdat->source) {
+            _LOGD(context,
+                  "failed opening tty " RFCOMM_FMT ": %s (%d). Start polling...",
+                  context->rfcomm_tty_no,
+                  nm_strerror_native(errsv),
+                  errsv);
+            context->cdat->connect_open_tty_started_at = nm_utils_get_monotonic_timestamp_nsec();
+            context->cdat->source                      = nm_g_timeout_source_new(100,
+                                                            G_PRIORITY_DEFAULT,
+                                                            _connect_open_tty_retry_cb,
+                                                            context,
+                                                            NULL);
+            g_source_attach(context->cdat->source, NULL);
+        }
+        return -errsv;
+    }
+
+    context->rfcomm_tty_fd = fd;
+
+    context->rfcomm_tty_poll_source = nm_g_unix_fd_source_new(context->rfcomm_tty_fd,
+                                                              G_IO_ERR | G_IO_HUP,
+                                                              G_PRIORITY_DEFAULT,
+                                                              _rfcomm_tty_poll_cb,
+                                                              context,
+                                                              NULL);
+    g_source_attach(context->rfcomm_tty_poll_source, NULL);
+
+    _context_invoke_callback_success(context);
+    return 0;
+}
+
+static void
+_connect_create_rfcomm(NMBluez5DunContext *context)
+{
+    gs_free_error GError *error = NULL;
+    struct rfcomm_dev_req req;
+    int                   devid;
+    int                   errsv;
+    int                   r;
+
+    _LOGD(context, "connected to %s on channel %d", context->dst_str, context->rfcomm_channel);
+
+    /* Create an RFCOMM kernel device for the DUN channel */
+    memset(&req, 0, sizeof(req));
+    req.dev_id  = -1;
+    req.flags   = (1 << RFCOMM_REUSE_DLC) | (1 << RFCOMM_RELEASE_ONHUP);
+    req.channel = context->rfcomm_channel;
+    memcpy(&req.src, &context->src, ETH_ALEN);
+    memcpy(&req.dst, &context->dst, ETH_ALEN);
+    devid = ioctl(context->rfcomm_sock_fd, RFCOMMCREATEDEV, &req);
+    if (devid < 0) {
+        errsv = NM_ERRNO_NATIVE(errno);
+        if (errsv == EBADFD) {
+            /* hm. We use a non-blocking socket to connect. Above getsockopt(SOL_SOCKET,SO_ERROR) indicated
+             * success, but still now we fail with EBADFD. I think that is a bug and we should get the
+             * failure during connect().
+             *
+             * Anyway, craft a less confusing error message than
+             * "failed to create rfcomm device: File descriptor in bad state (77)". */
+            g_set_error(&error,
+                        NM_BT_ERROR,
+                        NM_BT_ERROR_DUN_CONNECT_FAILED,
+                        "unknown failure to connect to DUN device");
+        } else {
+            g_set_error(&error,
+                        NM_BT_ERROR,
+                        NM_BT_ERROR_DUN_CONNECT_FAILED,
+                        "failed to create rfcomm device: %s (%d)",
+                        nm_strerror_native(errsv),
+                        errsv);
+        }
+        _context_invoke_callback_fail_and_free(context, error);
+        return;
+    }
+
+    context->rfcomm_tty_no   = devid;
+    context->rfcomm_tty_path = g_strdup_printf(RFCOMM_FMT, devid);
+
+    r = _connect_open_tty(context);
+    if (r < 0) {
+        /* we created the rfcomm device, but cannot yet open it. That means, we are
+         * not yet fully connected. However, we notify the caller about "what we learned
+         * so far". Note that this happens synchronously.
+         *
+         * The purpose is that once we proceed synchronously, modem-manager races with
+         * the detection of the modem. We want to notify the caller first about the
+         * device name. */
+        context->cdat->callback(NULL,
+                                context->rfcomm_tty_path,
+                                NULL,
+                                context->cdat->callback_user_data);
+    }
+}
+
+static gboolean
+_connect_socket_connect_cb(int fd, GIOCondition condition, gpointer user_data)
+{
+    NMBluez5DunContext *context = user_data;
+    gs_free_error GError *error = NULL;
+    int                   errsv = 0;
+    socklen_t             slen  = sizeof(errsv);
+    int                   r;
+
+    nm_clear_g_source_inst(&context->cdat->source);
+
+    r = getsockopt(context->rfcomm_sock_fd, SOL_SOCKET, SO_ERROR, &errsv, &slen);
+
+    if (r < 0) {
+        errsv = errno;
+        g_set_error(&error,
+                    NM_BT_ERROR,
+                    NM_BT_ERROR_DUN_CONNECT_FAILED,
+                    "failed to complete connecting RFCOMM socket: %s (%d)",
+                    nm_strerror_native(errsv),
+                    errsv);
+        _context_invoke_callback_fail_and_free(context, error);
+        return G_SOURCE_REMOVE;
+    }
+
+    if (errsv != 0) {
+        g_set_error(&error,
+                    NM_BT_ERROR,
+                    NM_BT_ERROR_DUN_CONNECT_FAILED,
+                    "failed to connect RFCOMM socket: %s (%d)",
+                    nm_strerror_native(errsv),
+                    errsv);
+        _context_invoke_callback_fail_and_free(context, error);
+        return G_SOURCE_REMOVE;
+    }
+
+    _connect_create_rfcomm(context);
+    return G_SOURCE_REMOVE;
+}
+
+static void
+_connect_socket_connect(NMBluez5DunContext *context)
+{
+    gs_free_error GError *error = NULL;
+    struct sockaddr_rc    sa;
+    int                   errsv;
+
+    context->rfcomm_sock_fd =
+        socket(AF_BLUETOOTH, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK, BTPROTO_RFCOMM);
+    if (context->rfcomm_sock_fd < 0) {
+        errsv = errno;
+        g_set_error(&error,
+                    NM_BT_ERROR,
+                    NM_BT_ERROR_DUN_CONNECT_FAILED,
+                    "failed to create RFCOMM socket: %s (%d)",
+                    nm_strerror_native(errsv),
+                    errsv);
+        _context_invoke_callback_fail_and_free(context, error);
+        return;
+    }
+
+    /* Connect to the remote device */
+    memset(&sa, 0, sizeof(sa));
+    sa.rc_family  = AF_BLUETOOTH;
+    sa.rc_channel = 0;
+    memcpy(&sa.rc_bdaddr, &context->src, ETH_ALEN);
+    if (bind(context->rfcomm_sock_fd, (struct sockaddr *) &sa, sizeof(sa)) != 0) {
+        errsv = errno;
+        g_set_error(&error,
+                    NM_BT_ERROR,
+                    NM_BT_ERROR_DUN_CONNECT_FAILED,
+                    "failed to bind socket: %s (%d)",
+                    nm_strerror_native(errsv),
+                    errsv);
+        _context_invoke_callback_fail_and_free(context, error);
+        return;
+    }
+
+    memset(&sa, 0, sizeof(sa));
+    sa.rc_family  = AF_BLUETOOTH;
+    sa.rc_channel = context->rfcomm_channel;
+    memcpy(&sa.rc_bdaddr, &context->dst, ETH_ALEN);
+    if (connect(context->rfcomm_sock_fd, (struct sockaddr *) &sa, sizeof(sa)) != 0) {
+        errsv = errno;
+        if (errsv != EINPROGRESS) {
+            g_set_error(&error,
+                        NM_BT_ERROR,
+                        NM_BT_ERROR_DUN_CONNECT_FAILED,
+                        "failed to connect to remote device: %s (%d)",
+                        nm_strerror_native(errsv),
+                        errsv);
+            _context_invoke_callback_fail_and_free(context, error);
+            return;
+        }
+
+        _LOGD(context,
+              "connecting to %s on channel %d...",
+              context->dst_str,
+              context->rfcomm_channel);
+
+        context->cdat->source = nm_g_unix_fd_source_new(context->rfcomm_sock_fd,
+                                                        G_IO_OUT,
+                                                        G_PRIORITY_DEFAULT,
+                                                        _connect_socket_connect_cb,
+                                                        context,
+                                                        NULL);
+        g_source_attach(context->cdat->source, NULL);
+        return;
+    }
+
+    _connect_create_rfcomm(context);
+}
+
+static void
+_connect_sdp_search_cb(uint8_t type, uint16_t status, uint8_t *rsp, size_t size, void *user_data)
+{
+    NMBluez5DunContext *context = user_data;
+    int                 scanned;
+    int                 seqlen    = 0;
+    int                 bytesleft = size;
+    uint8_t             dataType;
+    int                 channel = -1;
+
+    if (context->cdat->rfcomm_sdp_search_error || context->rfcomm_channel >= 0)
+        return;
+
+    _LOGD(context, "SDP search finished with type=%d status=%d", status, type);
+
+    /* SDP response received */
+    if (status || type != SDP_SVC_SEARCH_ATTR_RSP) {
+        g_set_error(&context->cdat->rfcomm_sdp_search_error,
+                    NM_BT_ERROR,
+                    NM_BT_ERROR_DUN_CONNECT_FAILED,
+                    "did not get a Service Discovery response");
+        return;
+    }
+
+    scanned = sdp_extract_seqtype(rsp, bytesleft, &dataType, &seqlen);
+
+    _LOGD(context, "SDP sequence type scanned=%d length=%d", scanned, seqlen);
+
+    scanned = sdp_extract_seqtype(rsp, bytesleft, &dataType, &seqlen);
+    if (!scanned || !seqlen) {
+        /* Short read or unknown sequence type */
+        g_set_error(&context->cdat->rfcomm_sdp_search_error,
+                    NM_BT_ERROR,
+                    NM_BT_ERROR_DUN_CONNECT_FAILED,
+                    "improper Service Discovery response");
+        return;
+    }
+
+    rsp += scanned;
+    bytesleft -= scanned;
+    do {
+        sdp_record_t *rec;
+        int           recsize = 0;
+        sdp_list_t *  protos;
+
+        rec = sdp_extract_pdu(rsp, bytesleft, &recsize);
+        if (!rec)
+            break;
+
+        if (!recsize) {
+            sdp_record_free(rec);
+            break;
+        }
+
+        if (sdp_get_access_protos(rec, &protos) == 0) {
+            /* Extract the DUN channel number */
+            channel = sdp_get_proto_port(protos, RFCOMM_UUID);
+            sdp_list_free(protos, NULL);
+
+            _LOGD(context, "SDP channel=%d", channel);
+        }
+        sdp_record_free(rec);
+
+        scanned += recsize;
+        rsp += recsize;
+        bytesleft -= recsize;
+    } while (scanned < (ssize_t) size && bytesleft > 0 && channel < 0);
+
+    if (channel == -1) {
+        g_set_error(&context->cdat->rfcomm_sdp_search_error,
+                    NM_BT_ERROR,
+                    NM_BT_ERROR_DUN_CONNECT_FAILED,
+                    "did not receive rfcomm-channel");
+        return;
+    }
+
+    context->rfcomm_channel = channel;
+}
+
+static gboolean
+_connect_sdp_search_io_cb(int fd, GIOCondition condition, gpointer user_data)
+{
+    NMBluez5DunContext *context = user_data;
+    gs_free_error GError *error = NULL;
+    int                   errsv;
+
+    if (condition & (G_IO_ERR | G_IO_HUP | G_IO_NVAL)) {
+        _LOGD(context, "SDP search returned with invalid IO condition 0x%x", (guint) condition);
+        error = g_error_new(NM_BT_ERROR,
+                            NM_BT_ERROR_DUN_CONNECT_FAILED,
+                            "Service Discovery interrupted");
+        nm_clear_g_source_inst(&context->cdat->source);
+        _context_invoke_callback_fail_and_free(context, error);
+        return G_SOURCE_REMOVE;
+    }
+
+    if (sdp_process(context->cdat->sdp_session) == 0) {
+        _LOGD(context, "SDP search still not finished");
+        return G_SOURCE_CONTINUE;
+    }
+
+    nm_clear_g_source_inst(&context->cdat->source);
+
+    if (context->rfcomm_channel < 0 && !context->cdat->rfcomm_sdp_search_error) {
+        errsv = sdp_get_error(context->cdat->sdp_session);
+        _LOGD(context, "SDP search failed: %s (%d)", nm_strerror_native(errsv), errsv);
+        error = g_error_new(NM_BT_ERROR,
+                            NM_BT_ERROR_DUN_CONNECT_FAILED,
+                            "Service Discovery failed with %s (%d)",
+                            nm_strerror_native(errsv),
+                            errsv);
+        _context_invoke_callback_fail_and_free(context, error);
+        return G_SOURCE_REMOVE;
+    }
+
+    if (context->cdat->rfcomm_sdp_search_error) {
+        _LOGD(context,
+              "SDP search failed to complete: %s",
+              context->cdat->rfcomm_sdp_search_error->message);
+        _context_invoke_callback_fail_and_free(context, context->cdat->rfcomm_sdp_search_error);
+        return G_SOURCE_REMOVE;
+    }
+
+    nm_clear_pointer(&context->cdat->sdp_session, sdp_close);
+
+    _connect_socket_connect(context);
+
+    return G_SOURCE_REMOVE;
+}
+
+static gboolean
+_connect_sdp_session_start_on_idle_cb(gpointer user_data)
+{
+    NMBluez5DunContext *context = user_data;
+    gs_free_error GError *error = NULL;
+
+    nm_clear_g_source_inst(&context->cdat->source);
+
+    _LOGD(context, "retry starting sdp-session...");
+
+    if (!_connect_sdp_session_start(context, &error))
+        _context_invoke_callback_fail_and_free(context, error);
+
+    return G_SOURCE_REMOVE;
+}
+
+static gboolean
+_connect_sdp_io_cb(int fd, GIOCondition condition, gpointer user_data)
+{
+    NMBluez5DunContext *context = user_data;
+    sdp_list_t *        search;
+    sdp_list_t *        attrs;
+    uuid_t              svclass;
+    uint16_t            attr;
+    int                 errsv;
+    int                 fd_err = 0;
+    int                 r;
+    socklen_t           len     = sizeof(fd_err);
+    gs_free_error GError *error = NULL;
+
+    nm_clear_g_source_inst(&context->cdat->source);
+
+    _LOGD(context, "sdp-session ready to connect with fd=%d", fd);
+
+    if (getsockopt(fd, SOL_SOCKET, SO_ERROR, &fd_err, &len) < 0) {
+        errsv = NM_ERRNO_NATIVE(errno);
+        error = g_error_new(NM_BT_ERROR,
+                            NM_BT_ERROR_DUN_CONNECT_FAILED,
+                            "error for getsockopt on Service Discovery socket: %s (%d)",
+                            nm_strerror_native(errsv),
+                            errsv);
+        goto done;
+    }
+
+    if (fd_err != 0) {
+        errsv = nm_errno_native(fd_err);
+
+        if (NM_IN_SET(errsv, ECONNREFUSED, EHOSTDOWN)
+            && --context->cdat->sdp_session_try_count > 0) {
+            /* *sigh* */
+            _LOGD(context,
+                  "sdp-session failed with %s (%d). Retry in a bit",
+                  nm_strerror_native(errsv),
+                  errsv);
+            nm_clear_g_source_inst(&context->cdat->source);
+            context->cdat->source = nm_g_timeout_source_new(1000,
+                                                            G_PRIORITY_DEFAULT,
+                                                            _connect_sdp_session_start_on_idle_cb,
+                                                            context,
+                                                            NULL);
+            g_source_attach(context->cdat->source, NULL);
+            return G_SOURCE_REMOVE;
+        }
+
+        error = g_error_new(NM_BT_ERROR,
+                            NM_BT_ERROR_DUN_CONNECT_FAILED,
+                            "error on Service Discovery socket: %s (%d)",
+                            nm_strerror_native(errsv),
+                            errsv);
+        goto done;
+    }
+
+    if (sdp_set_notify(context->cdat->sdp_session, _connect_sdp_search_cb, context) < 0) {
+        /* Should not be reached, only can fail if we passed bad sdp_session. */
+        error = g_error_new(NM_BT_ERROR,
+                            NM_BT_ERROR_DUN_CONNECT_FAILED,
+                            "could not set Service Discovery notification");
+        goto done;
+    }
+
+    sdp_uuid16_create(&svclass, DIALUP_NET_SVCLASS_ID);
+    search = sdp_list_append(NULL, &svclass);
+    attr   = SDP_ATTR_PROTO_DESC_LIST;
+    attrs  = sdp_list_append(NULL, &attr);
+
+    r = sdp_service_search_attr_async(context->cdat->sdp_session,
+                                      search,
+                                      SDP_ATTR_REQ_INDIVIDUAL,
+                                      attrs);
+
+    sdp_list_free(attrs, NULL);
+    sdp_list_free(search, NULL);
+
+    if (r < 0) {
+        errsv = nm_errno_native(sdp_get_error(context->cdat->sdp_session));
+        error = g_error_new(NM_BT_ERROR,
+                            NM_BT_ERROR_DUN_CONNECT_FAILED,
+                            "error starting Service Discovery: %s (%d)",
+                            nm_strerror_native(errsv),
+                            errsv);
+        goto done;
+    }
+
+    /* Set callback responsible for update the internal SDP transaction */
+    context->cdat->source = nm_g_unix_fd_source_new(fd,
+                                                    G_IO_IN | G_IO_HUP | G_IO_ERR | G_IO_NVAL,
+                                                    G_PRIORITY_DEFAULT,
+                                                    _connect_sdp_search_io_cb,
+                                                    context,
+                                                    NULL);
+    g_source_attach(context->cdat->source, NULL);
+
+done:
+    if (error)
+        _context_invoke_callback_fail_and_free(context, error);
+    return G_SOURCE_REMOVE;
+}
+
+/*****************************************************************************/
+
+static void
+_connect_cancelled_cb(GCancellable *cancellable, NMBluez5DunContext *context)
+{
+    gs_free_error GError *error = NULL;
+
+    if (!g_cancellable_set_error_if_cancelled(cancellable, &error))
+        g_return_if_reached();
+
+    _context_invoke_callback_fail_and_free(context, error);
+}
+
+static gboolean
+_connect_sdp_session_start(NMBluez5DunContext *context, GError **error)
+{
+    nm_assert(context->cdat);
+
+    nm_clear_g_source_inst(&context->cdat->source);
+    nm_clear_pointer(&context->cdat->sdp_session, sdp_close);
+
+    context->cdat->sdp_session = sdp_connect(&context->src, &context->dst, SDP_NON_BLOCKING);
+    if (!context->cdat->sdp_session) {
+        int errsv = nm_errno_native(errno);
+
+        g_set_error(error,
+                    NM_BT_ERROR,
+                    NM_BT_ERROR_DUN_CONNECT_FAILED,
+                    "failed to connect to the SDP server: %s (%d)",
+                    nm_strerror_native(errsv),
+                    errsv);
+        return FALSE;
+    }
+
+    context->cdat->source = nm_g_unix_fd_source_new(sdp_get_socket(context->cdat->sdp_session),
+                                                    G_IO_OUT | G_IO_HUP | G_IO_ERR | G_IO_NVAL,
+                                                    G_PRIORITY_DEFAULT,
+                                                    _connect_sdp_io_cb,
+                                                    context,
+                                                    NULL);
+    g_source_attach(context->cdat->source, NULL);
+    return TRUE;
+}
+
+/*****************************************************************************/
+
+gboolean
+nm_bluez5_dun_connect(const char *                 adapter,
+                      const char *                 remote,
+                      GCancellable *               cancellable,
+                      NMBluez5DunConnectCb         callback,
+                      gpointer                     callback_user_data,
+                      NMBluez5DunNotifyTtyHangupCb notify_tty_hangup_cb,
+                      gpointer                     notify_tty_hangup_user_data,
+                      GError **                    error)
+{
+    nm_auto_free_context NMBluez5DunContext *context = NULL;
+    ConnectData *                            cdat;
+    gsize                                    src_l;
+    gsize                                    dst_l;
+
+    g_return_val_if_fail(adapter, FALSE);
+    g_return_val_if_fail(remote, FALSE);
+    g_return_val_if_fail(G_IS_CANCELLABLE(cancellable), FALSE);
+    g_return_val_if_fail(callback, FALSE);
+    g_return_val_if_fail(notify_tty_hangup_cb, FALSE);
+    g_return_val_if_fail(!error || !*error, FALSE);
+    nm_assert(!g_cancellable_is_cancelled(cancellable));
+
+    src_l = strlen(adapter) + 1;
+    dst_l = strlen(remote) + 1;
+
+    cdat  = g_slice_new(ConnectData);
+    *cdat = (ConnectData){
+        .callback              = callback,
+        .callback_user_data    = callback_user_data,
+        .cancellable           = g_object_ref(cancellable),
+        .sdp_session_try_count = 5,
+    };
+
+    context  = g_malloc(sizeof(NMBluez5DunContext) + src_l + dst_l);
+    *context = (NMBluez5DunContext){
+        .cdat                        = cdat,
+        .notify_tty_hangup_cb        = notify_tty_hangup_cb,
+        .notify_tty_hangup_user_data = notify_tty_hangup_user_data,
+        .rfcomm_tty_no               = -1,
+        .rfcomm_sock_fd              = -1,
+        .rfcomm_tty_fd               = -1,
+        .rfcomm_channel              = -1,
+    };
+    memcpy(&context->src_str[0], adapter, src_l);
+    context->dst_str = &context->src_str[src_l];
+    memcpy((char *) context->dst_str, remote, dst_l);
+
+    if (str2ba(adapter, &context->src) < 0) {
+        g_set_error(error, NM_BT_ERROR, NM_BT_ERROR_DUN_CONNECT_FAILED, "invalid source");
+        return FALSE;
+    }
+
+    if (str2ba(remote, &context->dst) < 0) {
+        g_set_error(error, NM_BT_ERROR, NM_BT_ERROR_DUN_CONNECT_FAILED, "invalid remote");
+        return FALSE;
+    }
+
+    context->cdat->cancelled_id = g_signal_connect(context->cdat->cancellable,
+                                                   "cancelled",
+                                                   G_CALLBACK(_connect_cancelled_cb),
+                                                   context);
+
+    if (!_connect_sdp_session_start(context, error))
+        return FALSE;
+
+    _LOGD(context, "starting channel number discovery for device %s", context->dst_str);
+
+    g_steal_pointer(&context);
+    return TRUE;
+}
+
+/*****************************************************************************/
+
+void
+nm_bluez5_dun_disconnect(NMBluez5DunContext *context)
+{
+    nm_assert(context);
+    nm_assert(!context->cdat);
+
+    _LOGD(context, "disconnecting DUN connection");
+
+    _context_free(context);
+}
+
+/*****************************************************************************/
+
+static void
+_context_cleanup_connect_data(NMBluez5DunContext *context)
+{
+    ConnectData *cdat;
+
+    cdat = g_steal_pointer(&context->cdat);
+    if (!cdat)
+        return;
+
+    nm_clear_g_signal_handler(cdat->cancellable, &cdat->cancelled_id);
+
+    nm_clear_g_source_inst(&cdat->source);
+
+    nm_clear_pointer(&cdat->sdp_session, sdp_close);
+
+    g_clear_object(&cdat->cancellable);
+
+    g_clear_error(&cdat->rfcomm_sdp_search_error);
+
+    nm_g_slice_free(cdat);
+}
+
+static void
+_context_invoke_callback(NMBluez5DunContext *context, GError *error)
+{
+    NMBluez5DunConnectCb callback;
+    gpointer             callback_user_data;
+
+    nm_assert(context);
+    nm_assert(context->cdat);
+    nm_assert(context->cdat->callback);
+    nm_assert(error || context->rfcomm_tty_path);
+
+    if (!error)
+        _LOGD(context, "connected via \"%s\"", context->rfcomm_tty_path);
+    else if (nm_utils_error_is_cancelled(error))
+        _LOGD(context, "cancelled");
+    else
+        _LOGD(context, "failed to connect: %s", error->message);
+
+    callback           = context->cdat->callback;
+    callback_user_data = context->cdat->callback_user_data;
+
+    _context_cleanup_connect_data(context);
+
+    callback(error ? NULL : context,
+             error ? NULL : context->rfcomm_tty_path,
+             error,
+             callback_user_data);
+}
+
+static void
+_context_invoke_callback_success(NMBluez5DunContext *context)
+{
+    nm_assert(context->rfcomm_tty_path);
+    _context_invoke_callback(context, NULL);
+}
+
+static void
+_context_invoke_callback_fail_and_free(NMBluez5DunContext *context, GError *error)
+{
+    nm_assert(error);
+    _context_invoke_callback(context, error);
+    _context_free(context);
+}
+
+static void
+_context_free(NMBluez5DunContext *context)
+{
+    nm_assert(context);
+
+    _context_cleanup_connect_data(context);
+
+    nm_clear_g_source_inst(&context->rfcomm_tty_poll_source);
+
+    if (context->rfcomm_sock_fd >= 0) {
+        if (context->rfcomm_tty_no >= 0) {
+            struct rfcomm_dev_req req;
+
+            memset(&req, 0, sizeof(struct rfcomm_dev_req));
+            req.dev_id             = context->rfcomm_tty_no;
+            context->rfcomm_tty_no = -1;
+            (void) ioctl(context->rfcomm_sock_fd, RFCOMMRELEASEDEV, &req);
+        }
+        nm_close(nm_steal_fd(&context->rfcomm_sock_fd));
+    }
+
+    if (context->rfcomm_tty_fd >= 0)
+        nm_close(nm_steal_fd(&context->rfcomm_tty_fd));
+    nm_clear_g_free(&context->rfcomm_tty_path);
+    g_free(context);
+}