laforge has submitted this change. ( https://gerrit.osmocom.org/c/osmo-msc/+/28113 ) Change subject: sms_queue: Annotate each function with some comment ...................................................................... sms_queue: Annotate each function with some comment It makes the code much more readable if there's at least a one-liner documenting each function (and struct member). Change-Id: I6d239369cabdf1703eba7f3606b46b95cbbb1ea7 --- M src/libmsc/sms_queue.c 1 file changed, 47 insertions(+), 29 deletions(-) Approvals: Jenkins Builder: Verified laforge: Looks good to me, approved; Verified pespin: Looks good to me, but someone else must approve fixeria: Looks good to me, but someone else must approve diff --git a/src/libmsc/sms_queue.c b/src/libmsc/sms_queue.c index 6098a53..63d9631 100644 --- a/src/libmsc/sms_queue.c +++ b/src/libmsc/sms_queue.c @@ -43,35 +43,39 @@ #include <osmocom/vty/vty.h> -/* - * One pending SMS that we wait for. - */ +/* One in-RAM record of a "pending SMS". This is not the SMS itself, but merely + * a pointer to the database record. It holds a reference on the vlr_subscriber + * and some counters. While this object exists in RAM, we are regularly attempting + * to deliver the related SMS. */ struct gsm_sms_pending { - struct llist_head entry; + struct llist_head entry; /* gsm_sms_queue.pending_sms */ - struct vlr_subscr *vsub; - struct msc_a *msc_a; - unsigned long long sms_id; - int failed_attempts; - int resend; + struct vlr_subscr *vsub; /* destination subscriber for this SMS */ + struct msc_a *msc_a; /* MSC_A associated with this SMS */ + unsigned long long sms_id; /* unique ID (in SQL database) of this SMS */ + int failed_attempts; /* count of failed deliver attempts so far */ + int resend; /* should we try re-sending it (now) ? */ }; +/* (global) state of the SMS queue. */ struct gsm_sms_queue { - struct osmo_timer_list resend_pending; - struct osmo_timer_list push_queue; + struct osmo_timer_list resend_pending; /* timer triggering sms_resend_pending() */ + struct osmo_timer_list push_queue; /* timer triggering sms_submit_pending() */ struct gsm_network *network; - int max_fail; - int max_pending; - int pending; + int max_fail; /* maximum number of delivery failures */ + int max_pending; /* maximum number of gsm_sms_pending in RAM */ + int pending; /* current number of gsm_sms_pending in RAM */ - struct llist_head pending_sms; + struct llist_head pending_sms; /* list of gsm_sms_pending */ + /* last MSISDN for which we read SMS from the database and created gsm_sms_pending records */ char last_msisdn[GSM23003_MSISDN_MAX_DIGITS+1]; }; static int sms_subscr_cb(unsigned int, unsigned int, void *, void *); static int sms_sms_cb(unsigned int, unsigned int, void *, void *); +/* look-up a 'gsm_sms_pending' for the given sms_id; return NULL if none */ static struct gsm_sms_pending *sms_find_pending(struct gsm_sms_queue *smsq, unsigned long long sms_id) { @@ -85,11 +89,13 @@ return NULL; } +/* do we currently have a gsm_sms_pending object for the given SMS id? */ int sms_queue_sms_is_pending(struct gsm_sms_queue *smsq, unsigned long long sms_id) { return sms_find_pending(smsq, sms_id) != NULL; } +/* find the first pending SMS (in RAM) for the given subscriber */ static struct gsm_sms_pending *sms_subscriber_find_pending( struct gsm_sms_queue *smsq, struct vlr_subscr *vsub) @@ -104,12 +110,14 @@ return NULL; } +/* do we have any pending SMS (in RAM) for the given subscriber? */ static int sms_subscriber_is_pending(struct gsm_sms_queue *smsq, struct vlr_subscr *vsub) { return sms_subscriber_find_pending(smsq, vsub) != NULL; } +/* allocate a new gsm_sms_pending record and fill it with information from 'sms' */ static struct gsm_sms_pending *sms_pending_from(struct gsm_sms_queue *smsq, struct gsm_sms *sms) { @@ -125,6 +133,7 @@ return pending; } +/* release a gsm_sms_pending object */ static void sms_pending_free(struct gsm_sms_pending *pending) { vlr_subscr_put(pending->vsub, VSUB_USE_SMS_PENDING); @@ -132,6 +141,8 @@ talloc_free(pending); } +/* this sets the 'resend' flag of the gsm_sms_pending and schedules + * the timer for re-sending */ static void sms_pending_resend(struct gsm_sms_pending *pending) { struct gsm_network *net = pending->vsub->vlr->user_ctx; @@ -148,6 +159,8 @@ osmo_timer_schedule(&smsq->resend_pending, 1, 0); } +/* call-back when a pending SMS has failed; try another re-send if number of + * attempts is < smsq->max_fail */ static void sms_pending_failed(struct gsm_sms_pending *pending, int paging_error) { struct gsm_network *net = pending->vsub->vlr->user_ctx; @@ -165,10 +178,10 @@ smsq->pending -= 1; } -/* - * Resend all SMS that are scheduled for a resend. This is done to - * avoid an immediate failure. - */ +/* Resend all SMS that are scheduled for a resend. This is done to + * avoid an immediate failure. This iterates over all the (in RAM) + * pending_sms records, checks for resend == true, reads them from the + * DB and attempts to send them via gsm411_send_sms() */ static void sms_resend_pending(void *_data) { struct gsm_sms_pending *pending, *tmp; @@ -244,10 +257,10 @@ return NULL; } -/** - * I will submit up to max_pending - pending SMS to the - * subsystem. - */ +/* read up to 'max_pending' pending SMS from the database and add them to the in-memory + * sms_queue; trigger the first delivery attempt. 'submit' in this context means + * "read from the database and add to the in-memory gsm_sms_queue" and is not to be + * confused with the SMS SUBMIT operation a MS performs when sending a MO-SMS. */ static void sms_submit_pending(void *_data) { struct gsm_sms_queue *smsq = _data; @@ -309,6 +322,7 @@ continue; } + /* allocate a new gsm_sms_pending object in RAM */ pending = sms_pending_from(smsq, sms); if (!pending) { LOGP(DLSMS, LOGL_ERROR, @@ -326,9 +340,10 @@ LOGP(DLSMS, LOGL_DEBUG, "SMSqueue added %d messages in %d rounds\n", attempted, rounds); } -/** - * Send the next SMS or trigger the queue - */ +/* obtain the next pending SMS for given subscriber from database, + * create gsm_sms_pending object and attempt first delivery. If there + * are no SMS pending for the given subscriber, call sms_submit_pending() + * to read more SMS (for any subscriber) into the in-RAM pending queue */ static void sms_send_next(struct vlr_subscr *vsub) { struct gsm_network *net = vsub->vlr->user_ctx; @@ -366,9 +381,7 @@ sms_submit_pending(net->sms_queue); } -/* - * Kick off the queue again. - */ +/* Trigger a call to sms_submit_pending() in one second */ int sms_queue_trigger(struct gsm_sms_queue *smsq) { LOGP(DLSMS, LOGL_DEBUG, "Triggering SMS queue\n"); @@ -379,6 +392,8 @@ return 0; } +/* initialize the sms_queue subsystem and read the first batch of SMS from + * the database for delivery */ int sms_queue_start(struct gsm_network *network, int max_pending) { struct gsm_sms_queue *sms = talloc_zero(network, struct gsm_sms_queue); @@ -403,6 +418,7 @@ return 0; } +/* call-back: Given subscriber is now ready for short messages. */ static int sub_ready_for_sm(struct gsm_network *net, struct vlr_subscr *vsub) { struct gsm_sms *sms; @@ -440,6 +456,7 @@ return 0; } +/* call-back for SS_SUBSCR signals */ static int sms_subscr_cb(unsigned int subsys, unsigned int signal, void *handler_data, void *signal_data) { @@ -452,6 +469,7 @@ return sub_ready_for_sm(handler_data, vsub); } +/* call-back for SS_SMS signals */ static int sms_sms_cb(unsigned int subsys, unsigned int signal, void *handler_data, void *signal_data) { -- To view, visit https://gerrit.osmocom.org/c/osmo-msc/+/28113 To unsubscribe, or for help writing mail filters, visit https://gerrit.osmocom.org/settings Gerrit-Project: osmo-msc Gerrit-Branch: master Gerrit-Change-Id: I6d239369cabdf1703eba7f3606b46b95cbbb1ea7 Gerrit-Change-Number: 28113 Gerrit-PatchSet: 3 Gerrit-Owner: laforge &lt;laforge(a)osmocom.org&gt; Gerrit-Reviewer: Jenkins Builder Gerrit-Reviewer: fixeria &lt;vyanitskiy(a)sysmocom.de&gt; Gerrit-Reviewer: laforge &lt;laforge(a)osmocom.org&gt; Gerrit-Reviewer: pespin &lt;pespin(a)sysmocom.de&gt; Gerrit-MessageType: merged