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Diffstat (limited to 'src/lib/dispatch/dispatch_core.c')
-rw-r--r-- | src/lib/dispatch/dispatch_core.c | 260 |
1 files changed, 260 insertions, 0 deletions
diff --git a/src/lib/dispatch/dispatch_core.c b/src/lib/dispatch/dispatch_core.c new file mode 100644 index 0000000000..3d51c876a7 --- /dev/null +++ b/src/lib/dispatch/dispatch_core.c @@ -0,0 +1,260 @@ +/* Copyright (c) 2001, Matej Pfajfar. + * Copyright (c) 2001-2004, Roger Dingledine. + * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson. + * Copyright (c) 2007-2020, The Tor Project, Inc. */ +/* See LICENSE for licensing information */ + +/** + * \file dispatch_core.c + * \brief Core module for sending and receiving messages. + */ + +#define DISPATCH_PRIVATE +#include "orconfig.h" + +#include "lib/dispatch/dispatch.h" +#include "lib/dispatch/dispatch_st.h" +#include "lib/dispatch/dispatch_naming.h" + +#include "lib/malloc/malloc.h" +#include "lib/log/util_bug.h" + +#include <string.h> + +/** + * Use <b>d</b> to drop all storage held for <b>msg</b>. + * + * (We need the dispatcher so we know how to free the auxiliary data.) + **/ +void +dispatch_free_msg_(const dispatch_t *d, msg_t *msg) +{ + if (!msg) + return; + + d->typefns[msg->type].free_fn(msg->aux_data__); + tor_free(msg); +} + +/** + * Format the auxiliary data held by msg. + **/ +char * +dispatch_fmt_msg_data(const dispatch_t *d, const msg_t *msg) +{ + if (!msg) + return NULL; + + return d->typefns[msg->type].fmt_fn(msg->aux_data__); +} + +/** + * Release all storage held by <b>d</b>. + **/ +void +dispatch_free_(dispatch_t *d) +{ + if (d == NULL) + return; + + size_t n_queues = d->n_queues; + for (size_t i = 0; i < n_queues; ++i) { + msg_t *m, *mtmp; + TOR_SIMPLEQ_FOREACH_SAFE(m, &d->queues[i].queue, next, mtmp) { + dispatch_free_msg(d, m); + } + } + + size_t n_msgs = d->n_msgs; + + for (size_t i = 0; i < n_msgs; ++i) { + tor_free(d->table[i]); + } + tor_free(d->table); + tor_free(d->typefns); + tor_free(d->queues); + + // This is the only time we will treat d->cfg as non-const. + //dispatch_cfg_free_((dispatch_items_t *) d->cfg); + + tor_free(d); +} + +/** + * Tell the dispatcher to call <b>fn</b> with <b>userdata</b> whenever + * <b>chan</b> becomes nonempty. Return 0 on success, -1 on error. + **/ +int +dispatch_set_alert_fn(dispatch_t *d, channel_id_t chan, + dispatch_alertfn_t fn, void *userdata) +{ + if (BUG(chan >= d->n_queues)) + return -1; + + dqueue_t *q = &d->queues[chan]; + q->alert_fn = fn; + q->alert_fn_arg = userdata; + return 0; +} + +/** + * Send a message on the appropriate channel notifying that channel if + * necessary. + * + * This function takes ownership of the auxiliary data; it can't be static or + * stack-allocated, and the caller is not allowed to use it afterwards. + * + * This function does not check the various vields of the message object for + * consistency. + **/ +int +dispatch_send(dispatch_t *d, + subsys_id_t sender, + channel_id_t channel, + message_id_t msg, + msg_type_id_t type, + msg_aux_data_t auxdata) +{ + if (!d->table[msg]) { + /* Fast path: nobody wants this data. */ + + d->typefns[type].free_fn(auxdata); + return 0; + } + + msg_t *m = tor_malloc(sizeof(msg_t)); + + m->sender = sender; + m->channel = channel; + m->msg = msg; + m->type = type; + memcpy(&m->aux_data__, &auxdata, sizeof(msg_aux_data_t)); + + return dispatch_send_msg(d, m); +} + +int +dispatch_send_msg(dispatch_t *d, msg_t *m) +{ + if (BUG(!d)) + goto err; + if (BUG(!m)) + goto err; + if (BUG(m->channel >= d->n_queues)) + goto err; + if (BUG(m->msg >= d->n_msgs)) + goto err; + + dtbl_entry_t *ent = d->table[m->msg]; + if (ent) { + if (BUG(m->type != ent->type)) + goto err; + if (BUG(m->channel != ent->channel)) + goto err; + } + + return dispatch_send_msg_unchecked(d, m); + err: + /* Probably it isn't safe to free m, since type could be wrong. */ + return -1; +} + +/** + * Send a message on the appropriate queue, notifying that queue if necessary. + * + * This function takes ownership of the message object and its auxiliary data; + * it can't be static or stack-allocated, and the caller isn't allowed to use + * it afterwards. + * + * This function does not check the various fields of the message object for + * consistency, and can crash if they are out of range. Only functions that + * have already constructed the message in a safe way, or checked it for + * correctness themselves, should call this function. + **/ +int +dispatch_send_msg_unchecked(dispatch_t *d, msg_t *m) +{ + /* Find the right queue. */ + dqueue_t *q = &d->queues[m->channel]; + bool was_empty = TOR_SIMPLEQ_EMPTY(&q->queue); + + /* Append the message. */ + TOR_SIMPLEQ_INSERT_TAIL(&q->queue, m, next); + + if (debug_logging_enabled()) { + char *arg = dispatch_fmt_msg_data(d, m); + log_debug(LD_MESG, + "Queued: %s (%s) from %s, on %s.", + get_message_id_name(m->msg), + arg, + get_subsys_id_name(m->sender), + get_channel_id_name(m->channel)); + tor_free(arg); + } + + /* If we just made the queue nonempty for the first time, call the alert + * function. */ + if (was_empty) { + q->alert_fn(d, m->channel, q->alert_fn_arg); + } + + return 0; +} + +/** + * Run all of the callbacks on <b>d</b> associated with <b>m</b>. + **/ +static void +dispatcher_run_msg_cbs(const dispatch_t *d, msg_t *m) +{ + tor_assert(m->msg <= d->n_msgs); + dtbl_entry_t *ent = d->table[m->msg]; + int n_fns = ent->n_fns; + + if (debug_logging_enabled()) { + char *arg = dispatch_fmt_msg_data(d, m); + log_debug(LD_MESG, + "Delivering: %s (%s) from %s, on %s:", + get_message_id_name(m->msg), + arg, + get_subsys_id_name(m->sender), + get_channel_id_name(m->channel)); + tor_free(arg); + } + + int i; + for (i=0; i < n_fns; ++i) { + if (ent->rcv[i].enabled) { + log_debug(LD_MESG, " Delivering to %s.", + get_subsys_id_name(ent->rcv[i].sys)); + ent->rcv[i].fn(m); + } + } +} + +/** + * Run up to <b>max_msgs</b> callbacks for messages on the channel <b>ch</b> + * on the given dispatcher. Return 0 on success or recoverable failure, + * -1 on unrecoverable error. + **/ +int +dispatch_flush(dispatch_t *d, channel_id_t ch, int max_msgs) +{ + if (BUG(ch >= d->n_queues)) + return 0; + + int n_flushed = 0; + dqueue_t *q = &d->queues[ch]; + + while (n_flushed < max_msgs) { + msg_t *m = TOR_SIMPLEQ_FIRST(&q->queue); + if (!m) + break; + TOR_SIMPLEQ_REMOVE_HEAD(&q->queue, next); + dispatcher_run_msg_cbs(d, m); + dispatch_free_msg(d, m); + ++n_flushed; + } + + return 0; +} |