diff options
author | Mark Michelson <mmichelson@digium.com> | 2016-10-17 14:18:57 -0500 |
---|---|---|
committer | Mark Michelson <mmichelson@digium.com> | 2016-10-20 12:50:02 -0500 |
commit | eff97808fb95e4f9de13c90990f8ef5435352f31 (patch) | |
tree | bc9a5b59bc9346a38a895d9f50a1e9898cb1caac /main | |
parent | 546ec4b038ac3d750c5138d7fbb8e3ce93f482df (diff) |
ARI: Detect duplicate channel IDs
ARI and AMI allow for an explicit channel ID to be specified
when originating channels. Unfortunately, there is nothing in
place to prevent someone from using the same ID for multiple
channels. Further complicating things, adding ID validation to channel
allocation makes it impossible for ARI to discern why channel allocation
failed, resulting in a vague error code being returned.
The fix for this is to institute a new method for channel errors to be
discerned. The method mirrors errno, in that when an error occurs, the
caller can consult the channel errno value to determine what the error
was. This initial iteration of the feature only introduces "unknown" and
"channel ID exists" errors. However, it's possible to add more errors as
needed.
ARI uses this feature to determine why channel allocation failed and can
return a 409 error during origination to show that a channel with the
given ID already exists.
ASTERISK-26421
Change-Id: Ibba7ae68842dab6df0c2e9c45559208bc89d3d06
Diffstat (limited to 'main')
-rw-r--r-- | main/channel.c | 53 | ||||
-rw-r--r-- | main/channel_internal_api.c | 23 |
2 files changed, 71 insertions, 5 deletions
diff --git a/main/channel.c b/main/channel.c index c6cb925b8..278104cc9 100644 --- a/main/channel.c +++ b/main/channel.c @@ -767,6 +767,27 @@ static const struct ast_channel_tech null_tech = { static void ast_channel_destructor(void *obj); static void ast_dummy_channel_destructor(void *obj); +static int ast_channel_by_uniqueid_cb(void *obj, void *arg, void *data, int flags); + +static int does_id_conflict(const char *uniqueid) +{ + struct ast_channel *conflict; + int length = 0; + + if (ast_strlen_zero(uniqueid)) { + return 0; + } + + conflict = ast_channel_callback(ast_channel_by_uniqueid_cb, (char *) uniqueid, &length, OBJ_NOLOCK); + if (conflict) { + ast_log(LOG_ERROR, "Channel Unique ID '%s' already in use by channel %s(%p)\n", + uniqueid, ast_channel_name(conflict), conflict); + ast_channel_unref(conflict); + return 1; + } + + return 0; +} /*! \brief Create a new channel structure */ static struct ast_channel * attribute_malloc __attribute__((format(printf, 15, 0))) @@ -940,16 +961,33 @@ __ast_channel_alloc_ap(int needqueue, int state, const char *cid_num, const char ast_channel_tech_set(tmp, &null_tech); } - ast_channel_internal_finalize(tmp); - - ast_atomic_fetchadd_int(&chancount, +1); - /* You might scream "locking inversion" at seeing this but it is actually perfectly fine. * Since the channel was just created nothing can know about it yet or even acquire it. */ ast_channel_lock(tmp); - ao2_link(channels, tmp); + ao2_lock(channels); + + if (assignedids && (does_id_conflict(assignedids->uniqueid) || does_id_conflict(assignedids->uniqueid2))) { + ast_channel_internal_errno_set(AST_CHANNEL_ERROR_ID_EXISTS); + ao2_unlock(channels); + /* This is a bit unorthodox, but we can't just call ast_channel_stage_snapshot_done() + * because that will result in attempting to publish the channel snapshot. That causes + * badness in some places, such as CDRs. So we need to manually clear the flag on the + * channel that says that a snapshot is being cleared. + */ + ast_clear_flag(ast_channel_flags(tmp), AST_FLAG_SNAPSHOT_STAGE); + ast_channel_unlock(tmp); + return ast_channel_unref(tmp); + } + + ast_channel_internal_finalize(tmp); + + ast_atomic_fetchadd_int(&chancount, +1); + + ao2_link_flags(channels, tmp, OBJ_NOLOCK); + + ao2_unlock(channels); if (endpoint) { ast_endpoint_add_channel(endpoint, tmp); @@ -10842,3 +10880,8 @@ int ast_channel_feature_hooks_replace(struct ast_channel *chan, struct ast_bridg { return channel_feature_hooks_set_full(chan, features, 1); } + +enum ast_channel_error ast_channel_errno(void) +{ + return ast_channel_internal_errno(); +} diff --git a/main/channel_internal_api.c b/main/channel_internal_api.c index 51d49c29f..90f59d64a 100644 --- a/main/channel_internal_api.c +++ b/main/channel_internal_api.c @@ -1484,6 +1484,7 @@ static int pvt_cause_cmp_fn(void *obj, void *vstr, int flags) struct ast_channel *__ast_channel_internal_alloc(void (*destructor)(void *obj), const struct ast_assigned_ids *assignedids, const struct ast_channel *requestor, const char *file, int line, const char *function) { struct ast_channel *tmp; + #if defined(REF_DEBUG) tmp = __ao2_alloc_debug(sizeof(*tmp), destructor, AO2_ALLOC_OPT_LOCK_MUTEX, "", file, line, function, 1); @@ -1675,3 +1676,25 @@ int ast_channel_internal_setup_topics(struct ast_channel *chan) return 0; } + +AST_THREADSTORAGE(channel_errno); + +void ast_channel_internal_errno_set(enum ast_channel_error error) +{ + enum ast_channel_error *error_code = ast_threadstorage_get(&channel_errno, sizeof(*error_code)); + if (!error_code) { + return; + } + + *error_code = error; +} + +enum ast_channel_error ast_channel_internal_errno(void) +{ + enum ast_channel_error *error_code = ast_threadstorage_get(&channel_errno, sizeof(*error_code)); + if (!error_code) { + return AST_CHANNEL_ERROR_UNKNOWN; + } + + return *error_code; +} |