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/*
* Copyright 2022-2023 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the Apache License 2.0 (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#include "internal/quic_demux.h"
#include "internal/quic_wire_pkt.h"
#include "internal/common.h"
#include <openssl/lhash.h>
#include <openssl/err.h>
#define URXE_DEMUX_STATE_FREE 0 /* on urx_free list */
#define URXE_DEMUX_STATE_PENDING 1 /* on urx_pending list */
#define URXE_DEMUX_STATE_ISSUED 2 /* on neither list */
#define DEMUX_MAX_MSGS_PER_CALL 32
#define DEMUX_DEFAULT_MTU 1500
struct quic_demux_st {
/* The underlying transport BIO with datagram semantics. */
BIO *net_bio;
/*
* QUIC short packets do not contain the length of the connection ID field,
* therefore it must be known contextually. The demuxer requires connection
* IDs of the same length to be used for all incoming packets.
*/
size_t short_conn_id_len;
/*
* Our current understanding of the upper bound on an incoming datagram size
* in bytes.
*/
size_t mtu;
/* The datagram_id to use for the next datagram we receive. */
uint64_t next_datagram_id;
/* Time retrieval callback. */
OSSL_TIME (*now)(void *arg);
void *now_arg;
/* The default packet handler, if any. */
ossl_quic_demux_cb_fn *default_cb;
void *default_cb_arg;
/*
* List of URXEs which are not currently in use (i.e., not filled with
* unconsumed data). These are moved to the pending list as they are filled.
*/
QUIC_URXE_LIST urx_free;
/*
* List of URXEs which are filled with received encrypted data. These are
* removed from this list as we invoke the callbacks for each of them. They
* are then not on any list managed by us; we forget about them until our
* user calls ossl_quic_demux_release_urxe to return the URXE to us, at
* which point we add it to the free list.
*/
QUIC_URXE_LIST urx_pending;
/* Whether to use local address support. */
char use_local_addr;
};
QUIC_DEMUX *ossl_quic_demux_new(BIO *net_bio,
size_t short_conn_id_len,
OSSL_TIME (*now)(void *arg),
void *now_arg)
{
QUIC_DEMUX *demux;
demux = OPENSSL_zalloc(sizeof(QUIC_DEMUX));
if (demux == NULL)
return NULL;
demux->net_bio = net_bio;
demux->short_conn_id_len = short_conn_id_len;
/* We update this if possible when we get a BIO. */
demux->mtu = DEMUX_DEFAULT_MTU;
demux->now = now;
demux->now_arg = now_arg;
if (net_bio != NULL
&& BIO_dgram_get_local_addr_cap(net_bio)
&& BIO_dgram_set_local_addr_enable(net_bio, 1))
demux->use_local_addr = 1;
return demux;
}
static void demux_free_urxl(QUIC_URXE_LIST *l)
{
QUIC_URXE *e, *enext;
for (e = ossl_list_urxe_head(l); e != NULL; e = enext) {
enext = ossl_list_urxe_next(e);
ossl_list_urxe_remove(l, e);
OPENSSL_free(e);
}
}
void ossl_quic_demux_free(QUIC_DEMUX *demux)
{
if (demux == NULL)
return;
/* Free all URXEs we are holding. */
demux_free_urxl(&demux->urx_free);
demux_free_urxl(&demux->urx_pending);
OPENSSL_free(demux);
}
void ossl_quic_demux_set_bio(QUIC_DEMUX *demux, BIO *net_bio)
{
unsigned int mtu;
demux->net_bio = net_bio;
if (net_bio != NULL) {
/*
* Try to determine our MTU if possible. The BIO is not required to
* support this, in which case we remain at the last known MTU, or our
* initial default.
*/
mtu = BIO_dgram_get_mtu(net_bio);
if (mtu >= QUIC_MIN_INITIAL_DGRAM_LEN)
ossl_quic_demux_set_mtu(demux, mtu); /* best effort */
}
}
int ossl_quic_demux_set_mtu(QUIC_DEMUX *demux, unsigned int mtu)
{
if (mtu < QUIC_MIN_INITIAL_DGRAM_LEN)
return 0;
demux->mtu = mtu;
return 1;
}
void ossl_quic_demux_set_default_handler(QUIC_DEMUX *demux,
ossl_quic_demux_cb_fn *cb,
void *cb_arg)
{
demux->default_cb = cb;
demux->default_cb_arg = cb_arg;
}
static QUIC_URXE *demux_alloc_urxe(size_t alloc_len)
{
QUIC_URXE *e;
if (alloc_len >= SIZE_MAX - sizeof(QUIC_URXE))
return NULL;
e = OPENSSL_malloc(sizeof(QUIC_URXE) + alloc_len);
if (e == NULL)
return NULL;
ossl_list_urxe_init_elem(e);
e->alloc_len = alloc_len;
e->data_len = 0;
return e;
}
static QUIC_URXE *demux_resize_urxe(QUIC_DEMUX *demux, QUIC_URXE *e,
size_t new_alloc_len)
{
QUIC_URXE *e2, *prev;
if (!ossl_assert(e->demux_state == URXE_DEMUX_STATE_FREE))
/* Never attempt to resize a URXE which is not on the free list. */
return NULL;
prev = ossl_list_urxe_prev(e);
ossl_list_urxe_remove(&demux->urx_free, e);
e2 = OPENSSL_realloc(e, sizeof(QUIC_URXE) + new_alloc_len);
if (e2 == NULL) {
/* Failed to resize, abort. */
if (prev == NULL)
ossl_list_urxe_insert_head(&demux->urx_free, e);
else
ossl_list_urxe_insert_after(&demux->urx_free, prev, e);
return NULL;
}
if (prev == NULL)
ossl_list_urxe_insert_head(&demux->urx_free, e2);
else
ossl_list_urxe_insert_after(&demux->urx_free, prev, e2);
e2->alloc_len = new_alloc_len;
return e2;
}
static QUIC_URXE *demux_reserve_urxe(QUIC_DEMUX *demux, QUIC_URXE *e,
size_t alloc_len)
{
return e->alloc_len < alloc_len ? demux_resize_urxe(demux, e, alloc_len) : e;
}
static int demux_ensure_free_urxe(QUIC_DEMUX *demux, size_t min_num_free)
{
QUIC_URXE *e;
while (ossl_list_urxe_num(&demux->urx_free) < min_num_free) {
e = demux_alloc_urxe(demux->mtu);
if (e == NULL)
return 0;
ossl_list_urxe_insert_tail(&demux->urx_free, e);
e->demux_state = URXE_DEMUX_STATE_FREE;
}
return 1;
}
/*
* Receive datagrams from network, placing them into URXEs.
*
* Returns 1 on success or 0 on failure.
*
* Precondition: at least one URXE is free
* Precondition: there are no pending URXEs
*/
static int demux_recv(QUIC_DEMUX *demux)
{
BIO_MSG msg[DEMUX_MAX_MSGS_PER_CALL];
size_t rd, i;
QUIC_URXE *urxe = ossl_list_urxe_head(&demux->urx_free), *unext;
OSSL_TIME now;
/* This should never be called when we have any pending URXE. */
assert(ossl_list_urxe_head(&demux->urx_pending) == NULL);
assert(urxe->demux_state == URXE_DEMUX_STATE_FREE);
if (demux->net_bio == NULL)
/*
* If no BIO is plugged in, treat this as no datagram being available.
*/
return QUIC_DEMUX_PUMP_RES_TRANSIENT_FAIL;
/*
* Opportunistically receive as many messages as possible in a single
* syscall, determined by how many free URXEs are available.
*/
for (i = 0; i < (ossl_ssize_t)OSSL_NELEM(msg);
++i, urxe = ossl_list_urxe_next(urxe)) {
if (urxe == NULL) {
/* We need at least one URXE to receive into. */
if (!ossl_assert(i > 0))
return QUIC_DEMUX_PUMP_RES_PERMANENT_FAIL;
break;
}
/* Ensure the URXE is big enough. */
urxe = demux_reserve_urxe(demux, urxe, demux->mtu);
if (urxe == NULL)
/* Allocation error, fail. */
return QUIC_DEMUX_PUMP_RES_PERMANENT_FAIL;
/* Ensure we zero any fields added to BIO_MSG at a later date. */
memset(&msg[i], 0, sizeof(BIO_MSG));
msg[i].data = ossl_quic_urxe_data(urxe);
msg[i].data_len = urxe->alloc_len;
msg[i].peer = &urxe->peer;
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