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/* 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_new.c
* \brief Code to construct a dispatch_t from a dispatch_cfg_t.
**/
#define DISPATCH_NEW_PRIVATE
#define DISPATCH_PRIVATE
#include "orconfig.h"
#include "lib/dispatch/dispatch.h"
#include "lib/dispatch/dispatch_st.h"
#include "lib/dispatch/dispatch_cfg.h"
#include "lib/dispatch/dispatch_cfg_st.h"
#include "lib/cc/ctassert.h"
#include "lib/intmath/cmp.h"
#include "lib/malloc/malloc.h"
#include "lib/log/util_bug.h"
#include <string.h>
/** Given a smartlist full of (possibly NULL) pointers to uint16_t values,
* return the largest value, or dflt if the list is empty. */
STATIC int
max_in_u16_sl(const smartlist_t *sl, int dflt)
{
uint16_t *maxptr = NULL;
SMARTLIST_FOREACH_BEGIN(sl, uint16_t *, u) {
if (!maxptr)
maxptr = u;
else if (u && *u > *maxptr)
maxptr = u;
} SMARTLIST_FOREACH_END(u);
return maxptr ? *maxptr : dflt;
}
/* The above function is only safe to call if we are sure that channel_id_t
* and msg_type_id_t are really uint16_t. They should be so defined in
* msgtypes.h, but let's be extra cautious.
*/
CTASSERT(sizeof(uint16_t) == sizeof(msg_type_id_t));
CTASSERT(sizeof(uint16_t) == sizeof(channel_id_t));
/** Helper: Format an unformattable message auxiliary data item: just return a
* copy of the string <>. */
static char *
type_fmt_nop(msg_aux_data_t arg)
{
(void)arg;
return tor_strdup("<>");
}
/** Helper: Free an unfreeable message auxiliary data item: do nothing. */
static void
type_free_nop(msg_aux_data_t arg)
{
(void)arg;
}
/** Type functions to use when no type functions are provided. */
static dispatch_typefns_t nop_typefns = {
.free_fn = type_free_nop,
.fmt_fn = type_fmt_nop
};
/**
* Alert function to use when none is configured: do nothing.
**/
static void
alert_fn_nop(dispatch_t *d, channel_id_t ch, void *arg)
{
(void)d;
(void)ch;
(void)arg;
}
/**
* Given a list of recvfn_t, create and return a new dtbl_entry_t mapping
* to each of those functions.
**/
static dtbl_entry_t *
dtbl_entry_from_lst(smartlist_t *receivers)
{
if (!receivers)
return NULL;
size_t n_recv = smartlist_len(receivers);
dtbl_entry_t *ent;
ent = tor_malloc_zero(offsetof(dtbl_entry_t, rcv) +
sizeof(dispatch_rcv_t) * n_recv);
ent->n_fns = n_recv;
SMARTLIST_FOREACH_BEGIN(receivers, const dispatch_rcv_t *, rcv) {
memcpy(&ent->rcv[rcv_sl_idx], rcv, sizeof(*rcv));
if (rcv->enabled) {
++ent->n_enabled;
}
} SMARTLIST_FOREACH_END(rcv);
return ent;
}
/** Create and return a new dispatcher from a given dispatch_cfg_t. */
dispatch_t *
dispatch_new(const dispatch_cfg_t *cfg)
{
dispatch_t *d = tor_malloc_zero(sizeof(dispatch_t));
/* Any message that has a type or a receiver counts towards our messages */
const size_t n_msgs = MAX(smartlist_len(cfg->type_by_msg),
smartlist_len(cfg->recv_by_msg)) + 1;
/* Any channel that any message has counts towards the number of channels. */
const size_t n_chans = (size_t)
MAX(1, max_in_u16_sl(cfg->chan_by_msg,0)) + 1;
/* Any type that a message has, or that has functions, counts towards
* the number of types. */
const size_t n_types = (size_t) MAX(max_in_u16_sl(cfg->type_by_msg,0),
smartlist_len(cfg->fns_by_type)) + 1;
d->n_msgs = n_msgs;
d->n_queues = n_chans;
d->n_types = n_types;
/* Initialize the array of type-functions. */
d->typefns = tor_calloc(n_types, sizeof(dispatch_typefns_t));
for (size_t i = 0; i < n_types; ++i) {
/* Default to no-op for everything... */
memcpy(&d->typefns[i], &nop_typefns, sizeof(dispatch_typefns_t));
}
SMARTLIST_FOREACH_BEGIN(cfg->fns_by_type, dispatch_typefns_t *, fns) {
/* Set the functions if they are provided. */
if (fns) {
if (fns->free_fn)
d->typefns[fns_sl_idx].free_fn = fns->free_fn;
if (fns->fmt_fn)
d->typefns[fns_sl_idx].fmt_fn = fns->fmt_fn;
}
} SMARTLIST_FOREACH_END(fns);
/* Initialize the message queues: one for each channel. */
d->queues = tor_calloc(d->n_queues, sizeof(dqueue_t));
for (size_t i = 0; i < d->n_queues; ++i) {
TOR_SIMPLEQ_INIT(&d->queues[i].queue);
d->queues[i].alert_fn = alert_fn_nop;
}
/* Build the dispatch tables mapping message IDs to receivers. */
d->table = tor_calloc(d->n_msgs, sizeof(dtbl_entry_t *));
SMARTLIST_FOREACH_BEGIN(cfg->recv_by_msg, smartlist_t *, rcv) {
d->table[rcv_sl_idx] = dtbl_entry_from_lst(rcv);
} SMARTLIST_FOREACH_END(rcv);
/* Fill in the empty entries in the dispatch tables:
* types and channels for each message. */
SMARTLIST_FOREACH_BEGIN(cfg->type_by_msg, msg_type_id_t *, type) {
if (d->table[type_sl_idx])
d->table[type_sl_idx]->type = *type;
} SMARTLIST_FOREACH_END(type);
SMARTLIST_FOREACH_BEGIN(cfg->chan_by_msg, channel_id_t *, chan) {
if (d->table[chan_sl_idx])
d->table[chan_sl_idx]->channel = *chan;
} SMARTLIST_FOREACH_END(chan);
return d;
}
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