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openssl/ssl/quic/quic_txp.c
Matt Caswell e57bf6b3bf Keep track of connection credit as we add stream data 
If a single packet contains data from multiple streams we need to keep track
of the cummulative connection level credit consumed across all of the
streams. Once the connection level credit has been consumed we must stop
adding stream data.

Fixes #22706

Reviewed-by: Hugo Landau <hlandau@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/22718)
2023-11-15 09:08:16 +01:00

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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_txp.h"
#include "internal/quic_fifd.h"
#include "internal/quic_stream_map.h"
#include "internal/quic_error.h"
#include "internal/common.h"
#include <openssl/err.h>
#define MIN_CRYPTO_HDR_SIZE 3
#define MIN_FRAME_SIZE_HANDSHAKE_DONE 1
#define MIN_FRAME_SIZE_MAX_DATA 2
#define MIN_FRAME_SIZE_ACK 5
#define MIN_FRAME_SIZE_CRYPTO (MIN_CRYPTO_HDR_SIZE + 1)
#define MIN_FRAME_SIZE_STREAM 3 /* minimum useful size (for non-FIN) */
#define MIN_FRAME_SIZE_MAX_STREAMS_BIDI 2
#define MIN_FRAME_SIZE_MAX_STREAMS_UNI 2
/*
* Packet Archetypes
* =================
*/
/* Generate normal packets containing most frame types, subject to EL. */
#define TX_PACKETISER_ARCHETYPE_NORMAL 0
/*
* A probe packet is different in that:
* - It bypasses CC, but *is* counted as in flight for purposes of CC;
* - It must be ACK-eliciting.
*/
#define TX_PACKETISER_ARCHETYPE_PROBE 1
/*
* An ACK-only packet is different in that:
* - It bypasses CC, and is considered a 'non-inflight' packet;
* - It may not contain anything other than an ACK frame, not even padding.
*/
#define TX_PACKETISER_ARCHETYPE_ACK_ONLY 2
#define TX_PACKETISER_ARCHETYPE_NUM 3
struct ossl_quic_tx_packetiser_st {
OSSL_QUIC_TX_PACKETISER_ARGS args;
/*
* Opaque initial token blob provided by caller. TXP frees using the
* callback when it is no longer needed.
*/
const unsigned char *initial_token;
size_t initial_token_len;
ossl_quic_initial_token_free_fn *initial_token_free_cb;
void *initial_token_free_cb_arg;
/* Subcomponents of the TXP that we own. */
QUIC_FIFD fifd; /* QUIC Frame-in-Flight Dispatcher */
/* Internal state. */
uint64_t next_pn[QUIC_PN_SPACE_NUM]; /* Next PN to use in given PN space. */
OSSL_TIME last_tx_time; /* Last time a packet was generated, or 0. */
/* Internal state - frame (re)generation flags. */
unsigned int want_handshake_done : 1;
unsigned int want_max_data : 1;
unsigned int want_max_streams_bidi : 1;
unsigned int want_max_streams_uni : 1;
/* Internal state - frame (re)generation flags - per PN space. */
unsigned int want_ack : QUIC_PN_SPACE_NUM;
unsigned int force_ack_eliciting : QUIC_PN_SPACE_NUM;
/*
* Internal state - connection close terminal state.
* Once this is set, it is not unset unlike other want_ flags - we keep
* sending it in every packet.
*/
unsigned int want_conn_close : 1;
/* Has the handshake been completed? */
unsigned int handshake_complete : 1;
OSSL_QUIC_FRAME_CONN_CLOSE conn_close_frame;
/*
* Counts of the number of bytes received and sent while in the closing
* state.
*/
uint64_t closing_bytes_recv;
uint64_t closing_bytes_xmit;
/* Internal state - packet assembly. */
struct txp_el {
unsigned char *scratch; /* scratch buffer for packet assembly */
size_t scratch_len; /* number of bytes allocated for scratch */
OSSL_QTX_IOVEC *iovec; /* scratch iovec array for use with QTX */
size_t alloc_iovec; /* size of iovec array */
} el[QUIC_ENC_LEVEL_NUM];
/* Message callback related arguments */
ossl_msg_cb msg_callback;
void *msg_callback_arg;
SSL *msg_callback_ssl;
/* Callbacks. */
void (*ack_tx_cb)(const OSSL_QUIC_FRAME_ACK *ack,
uint32_t pn_space,
void *arg);
void *ack_tx_cb_arg;
};
/*
* The TX helper records state used while generating frames into packets. It
* enables serialization into the packet to be done "transactionally" where
* serialization of a frame can be rolled back if it fails midway (e.g. if it
* does not fit).
*/
struct tx_helper {
OSSL_QUIC_TX_PACKETISER *txp;
/*
* The Maximum Packet Payload Length in bytes. This is the amount of
* space we have to generate frames into.
*/
size_t max_ppl;
/*
* Number of bytes we have generated so far.
*/
size_t bytes_appended;
/*
* Number of scratch bytes in txp->scratch we have used so far. Some iovecs
* will reference this scratch buffer. When we need to use more of it (e.g.
* when we need to put frame headers somewhere), we append to the scratch
* buffer, resizing if necessary, and increase this accordingly.
*/
size_t scratch_bytes;
/*
* Bytes reserved in the MaxPPL budget. We keep this number of bytes spare
* until reserve_allowed is set to 1. Currently this is always at most 1, as
* a PING frame takes up one byte and this mechanism is only used to ensure
* we can encode a PING frame if we have been asked to ensure a packet is
* ACK-eliciting and we are unusure if we are going to add any other
* ACK-eliciting frames before we reach our MaxPPL budget.
*/
size_t reserve;
/*
* Number of iovecs we have currently appended. This is the number of
* entries valid in txp->iovec.
*/
size_t num_iovec;
/* The EL this TX helper is being used for. */
uint32_t enc_level;
/*
* Whether we are allowed to make use of the reserve bytes in our MaxPPL
* budget. This is used to ensure we have room to append a PING frame later
* if we need to. Once we know we will not need to append a PING frame, this
* is set to 1.
*/
unsigned int reserve_allowed : 1;
/*
* Set to 1 if we have appended a STREAM frame with an implicit length. If
* this happens we should never append another frame after that frame as it
* cannot be validly encoded. This is just a safety check.
*/
unsigned int done_implicit : 1;
struct {
/*
* The fields in this structure are valid if active is set, which means
* that a serialization transaction is currently in progress.
*/
unsigned char *data;
WPACKET wpkt;
unsigned int active : 1;
} txn;
};
static void tx_helper_rollback(struct tx_helper *h);
static int txp_el_ensure_iovec(struct txp_el *el, size_t num);
/* Initialises the TX helper. */
static int tx_helper_init(struct tx_helper *h, OSSL_QUIC_TX_PACKETISER *txp,
uint32_t enc_level, size_t max_ppl, size_t reserve)
{
if (reserve > max_ppl)
return 0;
h->txp = txp;
h->enc_level = enc_level;
h->max_ppl = max_ppl;
h->reserve = reserve;
h->num_iovec = 0;
h->bytes_appended = 0;
h->scratch_bytes = 0;
h->reserve_allowed = 0;
h->done_implicit = 0;
h->txn.data = NULL;
h->txn.active = 0;
if (max_ppl > h->txp->el[enc_level].scratch_len) {
unsigned char *scratch;
scratch = OPENSSL_realloc(h->txp->el[enc_level].scratch, max_ppl);
if (scratch == NULL)
return 0;
h->txp->el[enc_level].scratch = scratch;
h->txp->el[enc_level].scratch_len = max_ppl;
}
return 1;
}
static void tx_helper_cleanup(struct tx_helper *h)
{
if (h->txn.active)
tx_helper_rollback(h);
h->txp = NULL;
}
static void tx_helper_unrestrict(struct tx_helper *h)
{
h->reserve_allowed = 1;
}
/*
* Append an extent of memory to the iovec list. The memory must remain
* allocated until we finish generating the packet and call the QTX.
*
* In general, the buffers passed to this function will be from one of two
* ranges:
*
* - Application data contained in stream buffers managed elsewhere
* in the QUIC stack; or
*
* - Control frame data appended into txp->scratch using tx_helper_begin and
* tx_helper_commit.
*
*/
static int tx_helper_append_iovec(struct tx_helper *h,
const unsigned char *buf,
size_t buf_len)
{
struct txp_el *el = &h->txp->el[h->enc_level];
if (buf_len == 0)
return 1;
if (!ossl_assert(!h->done_implicit))
return 0;
if (!txp_el_ensure_iovec(el, h->num_iovec + 1))
return 0;
el->iovec[h->num_iovec].buf = buf;
el->iovec[h->num_iovec].buf_len = buf_len;
++h->num_iovec;
h->bytes_appended += buf_len;
return 1;
}
/*
* How many more bytes of space do we have left in our plaintext packet payload?
*/
static size_t tx_helper_get_space_left(struct tx_helper *h)
{
return h->max_ppl
- (h->reserve_allowed ? 0 : h->reserve) - h->bytes_appended;
}
/*
* Begin a control frame serialization transaction. This allows the
* serialization of the control frame to be backed out if it turns out it won't
* fit. Write the control frame to the returned WPACKET. Ensure you always
* call tx_helper_rollback or tx_helper_commit (or tx_helper_cleanup). Returns
* NULL on failure.
*/
static WPACKET *tx_helper_begin(struct tx_helper *h)
{
size_t space_left, len;
unsigned char *data;
struct txp_el *el = &h->txp->el[h->enc_level];
if (!ossl_assert(!h->txn.active))
return NULL;
if (!ossl_assert(!h->done_implicit))
return NULL;
data = (unsigned char *)el->scratch + h->scratch_bytes;
len = el->scratch_len - h->scratch_bytes;
space_left = tx_helper_get_space_left(h);
if (!ossl_assert(space_left <= len))
return NULL;
if (!WPACKET_init_static_len(&h->txn.wpkt, data, len, 0))
return NULL;
if (!WPACKET_set_max_size(&h->txn.wpkt, space_left)) {
WPACKET_cleanup(&h->txn.wpkt);
return NULL;
}
h->txn.data = data;
h->txn.active = 1;
return &h->txn.wpkt;
}
static void tx_helper_end(struct tx_helper *h, int success)
{
if (success)
WPACKET_finish(&h->txn.wpkt);
else
WPACKET_cleanup(&h->txn.wpkt);
h->txn.active = 0;
h->txn.data = NULL;
}
/* Abort a control frame serialization transaction. */
static void tx_helper_rollback(struct tx_helper *h)
{
if (!h->txn.active)
return;
tx_helper_end(h, 0);
}
/* Commit a control frame. */
static int tx_helper_commit(struct tx_helper *h)
{
size_t l = 0;
if (!h->txn.active)
return 0;
if (!WPACKET_get_total_written(&h->txn.wpkt, &l)) {
tx_helper_end(h, 0);
return 0;
}
if (!tx_helper_append_iovec(h, h->txn.data, l)) {
tx_helper_end(h, 0);
return 0;
}
if (h->txp->msg_callback != NULL && l > 0) {
uint64_t ftype;
int ctype = SSL3_RT_QUIC_FRAME_FULL;
PACKET pkt;
if (!PACKET_buf_init(&pkt, h->txn.data, l)
|| !ossl_quic_wire_peek_frame_header(&pkt, &ftype, NULL)) {
tx_helper_end(h, 0);
return 0;
}
if (ftype == OSSL_QUIC_FRAME_TYPE_PADDING)
ctype = SSL3_RT_QUIC_FRAME_PADDING;
else if (OSSL_QUIC_FRAME_TYPE_IS_STREAM(ftype)
|| ftype == OSSL_QUIC_FRAME_TYPE_CRYPTO)
ctype = SSL3_RT_QUIC_FRAME_HEADER;
h->txp->msg_callback(1, OSSL_QUIC1_VERSION, ctype, h->txn.data, l,
h->txp->msg_callback_ssl,
h->txp->msg_callback_arg);
}
h->scratch_bytes += l;
tx_helper_end(h, 1);
return 1;
}
struct archetype_data {
unsigned int allow_ack : 1;
unsigned int allow_ping : 1;
unsigned int allow_crypto : 1;
unsigned int allow_handshake_done : 1;
unsigned int allow_path_challenge : 1;
unsigned int allow_path_response : 1;
unsigned int allow_new_conn_id : 1;
unsigned int allow_retire_conn_id : 1;
unsigned int allow_stream_rel : 1;
unsigned int allow_conn_fc : 1;
unsigned int allow_conn_close : 1;
unsigned int allow_cfq_other : 1;
unsigned int allow_new_token : 1;
unsigned int allow_force_ack_eliciting : 1;
unsigned int allow_padding : 1;
unsigned int require_ack_eliciting : 1;
unsigned int bypass_cc : 1;
};
struct txp_pkt_geom {
size_t cmpl, cmppl, hwm, pkt_overhead;
uint32_t archetype;
struct archetype_data adata;
};
struct txp_pkt {
struct tx_helper h;
int h_valid;
QUIC_TXPIM_PKT *tpkt;
QUIC_STREAM *stream_head;
QUIC_PKT_HDR phdr;
struct txp_pkt_geom geom;
int force_pad;
};
static QUIC_SSTREAM *get_sstream_by_id(uint64_t stream_id, uint32_t pn_space,
void *arg);
static void on_regen_notify(uint64_t frame_type, uint64_t stream_id,
QUIC_TXPIM_PKT *pkt, void *arg);
static void on_confirm_notify(uint64_t frame_type, uint64_t stream_id,
QUIC_TXPIM_PKT *pkt, void *arg);
static void on_sstream_updated(uint64_t stream_id, void *arg);
static int sstream_is_pending(QUIC_SSTREAM *sstream);
static int txp_should_try_staging(OSSL_QUIC_TX_PACKETISER *txp,
uint32_t enc_level,
uint32_t archetype,
uint64_t cc_limit,
uint32_t *conn_close_enc_level);
static size_t txp_determine_pn_len(OSSL_QUIC_TX_PACKETISER *txp);
static int txp_determine_ppl_from_pl(OSSL_QUIC_TX_PACKETISER *txp,
size_t pl,
uint32_t enc_level,
size_t hdr_len,
size_t *r);
static size_t txp_get_mdpl(OSSL_QUIC_TX_PACKETISER *txp);
static int txp_generate_for_el(OSSL_QUIC_TX_PACKETISER *txp,
struct txp_pkt *pkt,
int chosen_for_conn_close);
static int txp_pkt_init(struct txp_pkt *pkt, OSSL_QUIC_TX_PACKETISER *txp,
uint32_t enc_level, uint32_t archetype,
size_t running_total);
static void txp_pkt_cleanup(struct txp_pkt *pkt, OSSL_QUIC_TX_PACKETISER *txp);
static int txp_pkt_postgen_update_pkt_overhead(struct txp_pkt *pkt,
OSSL_QUIC_TX_PACKETISER *txp);
static int txp_pkt_append_padding(struct txp_pkt *pkt,
OSSL_QUIC_TX_PACKETISER *txp, size_t num_bytes);
static int txp_pkt_commit(OSSL_QUIC_TX_PACKETISER *txp, struct txp_pkt *pkt,
uint32_t archetype, int *txpim_pkt_reffed);
static uint32_t txp_determine_archetype(OSSL_QUIC_TX_PACKETISER *txp,
uint64_t cc_limit);
OSSL_QUIC_TX_PACKETISER *ossl_quic_tx_packetiser_new(const OSSL_QUIC_TX_PACKETISER_ARGS *args)
{
OSSL_QUIC_TX_PACKETISER *txp;
if (args == NULL
|| args->qtx == NULL
|| args->txpim == NULL
|| args->cfq == NULL
|| args->ackm == NULL
|| args->qsm == NULL
|| args->conn_txfc == NULL
|| args->conn_rxfc == NULL
|| args->max_streams_bidi_rxfc == NULL
|| args->max_streams_uni_rxfc == NULL) {
ERR_raise(ERR_LIB_SSL, ERR_R_PASSED_NULL_PARAMETER);
return NULL;
}
txp = OPENSSL_zalloc(sizeof(*txp));
if (txp == NULL)
return NULL;
txp->args = *args;
txp->last_tx_time = ossl_time_zero();
if (!ossl_quic_fifd_init(&txp->fifd,
txp->args.cfq, txp->args.ackm, txp->args.txpim,
get_sstream_by_id, txp,
on_regen_notify, txp,
on_confirm_notify, txp,
on_sstream_updated, txp)) {
OPENSSL_free(txp);
return NULL;
}
return txp;
}
void ossl_quic_tx_packetiser_free(OSSL_QUIC_TX_PACKETISER *txp)
{
uint32_t enc_level;
if (txp == NULL)
return;
ossl_quic_tx_packetiser_set_initial_token(txp, NULL, 0, NULL, NULL);
ossl_quic_fifd_cleanup(&txp->fifd);
OPENSSL_free(txp->conn_close_frame.reason);
for (enc_level = QUIC_ENC_LEVEL_INITIAL;
enc_level < QUIC_ENC_LEVEL_NUM;
++enc_level) {
OPENSSL_free(txp->el[enc_level].iovec);
OPENSSL_free(txp->el[enc_level].scratch);
}
OPENSSL_free(txp);
}
/*
* Determine if an Initial packet token length is reasonable based on the
* current MDPL, returning 1 if it is OK.
*
* The real PMTU to the peer could differ from our (pessimistic) understanding
* of the PMTU, therefore it is possible we could receive an Initial token from
* a server in a Retry packet which is bigger than the MDPL. In this case it is
* impossible for us ever to make forward progress and we need to error out
* and fail the connection attempt.
*
* The specific boundary condition is complex: for example, after the size of
* the Initial token, there are the Initial packet header overheads and then
* encryption/AEAD tag overheads. After that, the minimum room for frame data in
* order to guarantee forward progress must be guaranteed. For example, a crypto
* stream needs to always be able to serialize at least one byte in a CRYPTO
* frame in order to make forward progress. Because the offset field of a CRYPTO
* frame uses a variable-length integer, the number of bytes needed to ensure
* this also varies.
*
* Rather than trying to get this boundary condition check actually right,
* require a reasonable amount of slack to avoid pathological behaviours. (After
* all, transmitting a CRYPTO stream one byte at a time is probably not
* desirable anyway.)
*
* We choose 160 bytes as the required margin, which is double the rough
* estimation of the minimum we would require to guarantee forward progress
* under worst case packet overheads.
*/
#define TXP_REQUIRED_TOKEN_MARGIN 160
static int txp_check_token_len(size_t token_len, size_t mdpl)
{
if (token_len == 0)
return 1;
if (token_len >= mdpl)
return 0;
if (TXP_REQUIRED_TOKEN_MARGIN >= mdpl)
/* (should not be possible because MDPL must be at least 1200) */
return 0;
if (token_len > mdpl - TXP_REQUIRED_TOKEN_MARGIN)
return 0;
return 1;
}
int ossl_quic_tx_packetiser_set_initial_token(OSSL_QUIC_TX_PACKETISER *txp,
const unsigned char *token,
size_t token_len,
ossl_quic_initial_token_free_fn *free_cb,
void *free_cb_arg)
{
if (!txp_check_token_len(token_len, txp_get_mdpl(txp)))
return 0;
if (txp->initial_token != NULL && txp->initial_token_free_cb != NULL)
txp->initial_token_free_cb(txp->initial_token, txp->initial_token_len,
txp->initial_token_free_cb_arg);
txp->initial_token = token;
txp->initial_token_len = token_len;
txp->initial_token_free_cb = free_cb;
txp->initial_token_free_cb_arg = free_cb_arg;
return 1;
}
int ossl_quic_tx_packetiser_set_cur_dcid(OSSL_QUIC_TX_PACKETISER *txp,
const QUIC_CONN_ID *dcid)
{
if (dcid == NULL) {
ERR_raise(ERR_LIB_SSL, ERR_R_PASSED_NULL_PARAMETER);
return 0;
}
txp->args.cur_dcid = *dcid;
return 1;
}
int ossl_quic_tx_packetiser_set_cur_scid(OSSL_QUIC_TX_PACKETISER *txp,
const QUIC_CONN_ID *scid)
{
if (scid == NULL) {
ERR_raise(ERR_LIB_SSL, ERR_R_PASSED_NULL_PARAMETER);
return 0;
}
txp->args.cur_scid = *scid;
return 1;
}
/* Change the destination L4 address the TXP uses to send datagrams. */
int ossl_quic_tx_packetiser_set_peer(OSSL_QUIC_TX_PACKETISER *txp,
const BIO_ADDR *peer)
{
if (peer == NULL) {
BIO_ADDR_clear(&txp->args.peer);
return 1;
}
txp->args.peer = *peer;
return 1;
}
void ossl_quic_tx_packetiser_set_ack_tx_cb(OSSL_QUIC_TX_PACKETISER *txp,
void (*cb)(const OSSL_QUIC_FRAME_ACK *ack,
uint32_t pn_space,
void *arg),
void *cb_arg)
{
txp->ack_tx_cb = cb;
txp->ack_tx_cb_arg = cb_arg;
}
int ossl_quic_tx_packetiser_discard_enc_level(OSSL_QUIC_TX_PACKETISER *txp,
uint32_t enc_level)
{
if (enc_level >= QUIC_ENC_LEVEL_NUM) {
ERR_raise(ERR_LIB_SSL, ERR_R_PASSED_INVALID_ARGUMENT);
return 0;
}
if (enc_level != QUIC_ENC_LEVEL_0RTT)
txp->args.crypto[ossl_quic_enc_level_to_pn_space(enc_level)] = NULL;
return 1;
}
void ossl_quic_tx_packetiser_notify_handshake_complete(OSSL_QUIC_TX_PACKETISER *txp)
{
txp->handshake_complete = 1;
}
void ossl_quic_tx_packetiser_schedule_handshake_done(OSSL_QUIC_TX_PACKETISER *txp)
{
txp->want_handshake_done = 1;
}
void ossl_quic_tx_packetiser_schedule_ack_eliciting(OSSL_QUIC_TX_PACKETISER *txp,
uint32_t pn_space)
{
txp->force_ack_eliciting |= (1UL << pn_space);
}
void ossl_quic_tx_packetiser_schedule_ack(OSSL_QUIC_TX_PACKETISER *txp,
uint32_t pn_space)
{
txp->want_ack |= (1UL << pn_space);
}
#define TXP_ERR_INTERNAL 0 /* Internal (e.g. alloc) error */
#define TXP_ERR_SUCCESS 1 /* Success */
#define TXP_ERR_SPACE 2 /* Not enough room for another packet */
#define TXP_ERR_INPUT 3 /* Invalid/malformed input */
/*
* Generates a datagram by polling the various ELs to determine if they want to
* generate any frames, and generating a datagram which coalesces packets for
* any ELs which do.
*/
int ossl_quic_tx_packetiser_generate(OSSL_QUIC_TX_PACKETISER *txp,
QUIC_TXP_STATUS *status)
{
/*
* Called to generate one or more datagrams, each containing one or more
* packets.
*
* There are some tricky things to note here:
*
* - The TXP is only concerned with generating encrypted packets;
* other packets use a different path.
*
* - Any datagram containing an Initial packet must have a payload length
* (DPL) of at least 1200 bytes. This padding need not necessarily be
* found in the Initial packet.
*
* - It is desirable to be able to coalesce an Initial packet
* with a Handshake packet. Since, before generating the Handshake
* packet, we do not know how long it will be, we cannot know the
* correct amount of padding to ensure a DPL of at least 1200 bytes.
* Thus this padding must added to the Handshake packet (or whatever
* packet is the last in the datagram).
*
* - However, at the time that we generate the Initial packet,
* we do not actually know for sure that we will be followed
* in the datagram by another packet. For example, suppose we have
* some queued data (e.g. crypto stream data for the HANDSHAKE EL)
* it looks like we will want to send on the HANDSHAKE EL.
* We could assume padding will be placed in the Handshake packet
* subsequently and avoid adding any padding to the Initial packet
* (which would leave no room for the Handshake packet in the
* datagram).
*
* However, this is not actually a safe assumption. Suppose that we
* are using a link with a MDPL of 1200 bytes, the minimum allowed by
* QUIC. Suppose that the Initial packet consumes 1195 bytes in total.
* Since it is not possible to fit a Handshake packet in just 5 bytes,
* upon trying to add a Handshake packet after generating the Initial
* packet, we will discover we have no room to fit it! This is not a
* problem in itself as another datagram can be sent subsequently, but
* it is a problem because we were counting to use that packet to hold
* the essential padding. But if we have already finished encrypting
* the Initial packet, we cannot go and add padding to it anymore.
* This leaves us stuck.
*
* Because of this, we have to plan multiple packets simultaneously, such
* that we can start generating a Handshake (or 0-RTT or 1-RTT, or so on)
* packet while still having the option to go back and add padding to the
* Initial packet if it turns out to be needed.
*
* Trying to predict ahead of time (e.g. during Initial packet generation)
* whether we will successfully generate a subsequent packet is fraught with
* error as it relies on a large number of variables:
*
* - Do we have room to fit a packet header? (Consider that due to
* variable-length integer encoding this is highly variable and can even
* depend on payload length due to a variable-length Length field.)
*
* - Can we fit even a single one of the frames we want to put in this
* packet in the packet? (Each frame type has a bespoke encoding. While
* our encodings of some frame types are adaptive based on the available
* room - e.g. STREAM frames - ultimately all frame types have some
* absolute minimum number of bytes to be successfully encoded. For
* example, if after an Initial packet there is enough room to encode
* only one byte of frame data, it is quite likely we can't send any of
* the frames we wanted to send.) While this is not strictly a problem
* because we could just fill the packet with padding frames, this is a
* pointless packet and is wasteful.
*
* Thus we adopt a multi-phase architecture:
*
* 1. Archetype Selection: Determine desired packet archetype.
*
* 2. Packet Staging: Generation of packet information and packet payload
* data (frame data) into staging areas.
*
* 3. Packet Adjustment: Adjustment of staged packets, adding padding to
* the staged packets if needed.
*
* 4. Commit: The packets are sent to the QTX and recorded as having been
* sent to the FIFM.
*
*/
int res = 0, rc;
uint32_t archetype, enc_level;
uint32_t conn_close_enc_level = QUIC_ENC_LEVEL_NUM;
struct txp_pkt pkt[QUIC_ENC_LEVEL_NUM];
size_t pkts_done = 0;
uint64_t cc_limit = txp->args.cc_method->get_tx_allowance(txp->args.cc_data);
int need_padding = 0, txpim_pkt_reffed;
for (enc_level = QUIC_ENC_LEVEL_INITIAL;
enc_level < QUIC_ENC_LEVEL_NUM;
++enc_level)
pkt[enc_level].h_valid = 0;
memset(status, 0, sizeof(*status));
/*
* Should not be needed, but a sanity check in case anyone else has been
* using the QTX.
*/
ossl_qtx_finish_dgram(txp->args.qtx);
/* 1. Archetype Selection */
archetype = txp_determine_archetype(txp, cc_limit);
/* 2. Packet Staging */
for (enc_level = QUIC_ENC_LEVEL_INITIAL;
enc_level < QUIC_ENC_LEVEL_NUM;
++enc_level) {
size_t running_total = (enc_level > QUIC_ENC_LEVEL_INITIAL)
? pkt[enc_level - 1].geom.hwm : 0;
pkt[enc_level].geom.hwm = running_total;
if (!txp_should_try_staging(txp, enc_level, archetype, cc_limit,
&conn_close_enc_level))
continue;
if (!txp_pkt_init(&pkt[enc_level], txp, enc_level, archetype,
running_total))
/*
* If this fails this is not a fatal error - it means the geometry
* planning determined there was not enough space for another
* packet. So just proceed with what we've already planned for.
*/
break;
rc = txp_generate_for_el(txp, &pkt[enc_level],
conn_close_enc_level == enc_level);
if (rc != TXP_ERR_SUCCESS)
goto out;
if (pkt[enc_level].force_pad)
/*
* txp_generate_for_el emitted a frame which forces packet padding.
*/
need_padding = 1;
pkt[enc_level].geom.hwm = running_total
+ pkt[enc_level].h.bytes_appended
+ pkt[enc_level].geom.pkt_overhead;
}
/* 3. Packet Adjustment */
if (pkt[QUIC_ENC_LEVEL_INITIAL].h_valid
&& pkt[QUIC_ENC_LEVEL_INITIAL].h.bytes_appended > 0)
/*
* We have an Initial packet in this datagram, so we need to make sure
* the total size of the datagram is adequate.
*/
need_padding = 1;
if (need_padding) {
size_t total_dgram_size = 0;
const size_t min_dpl = QUIC_MIN_INITIAL_DGRAM_LEN;
uint32_t pad_el = QUIC_ENC_LEVEL_NUM;
for (enc_level = QUIC_ENC_LEVEL_INITIAL;
enc_level < QUIC_ENC_LEVEL_NUM;
++enc_level)
if (pkt[enc_level].h_valid && pkt[enc_level].h.bytes_appended > 0) {
if (pad_el == QUIC_ENC_LEVEL_NUM
/*
* We might not be able to add padding, for example if we
* are using the ACK_ONLY archetype.
*/
&& pkt[enc_level].geom.adata.allow_padding
&& !pkt[enc_level].h.done_implicit)
pad_el = enc_level;
txp_pkt_postgen_update_pkt_overhead(&pkt[enc_level], txp);
total_dgram_size += pkt[enc_level].geom.pkt_overhead
+ pkt[enc_level].h.bytes_appended;
}
if (pad_el != QUIC_ENC_LEVEL_NUM && total_dgram_size < min_dpl) {
size_t deficit = min_dpl - total_dgram_size;
if (!txp_pkt_append_padding(&pkt[pad_el], txp, deficit))
goto out;
total_dgram_size += deficit;
/*
* Padding frames make a packet ineligible for being a non-inflight
* packet.
*/
pkt[pad_el].tpkt->ackm_pkt.is_inflight = 1;
}
/*
* If we have failed to make a datagram of adequate size, for example
* because we have a padding requirement but are using the ACK_ONLY
* archetype (because we are CC limited), which precludes us from
* sending padding, give up on generating the datagram - there is
* nothing we can do.
*/
if (total_dgram_size < min_dpl) {
res = 1;
goto out;
}
}
/* 4. Commit */
for (enc_level = QUIC_ENC_LEVEL_INITIAL;
enc_level < QUIC_ENC_LEVEL_NUM;
++enc_level) {
if (!pkt[enc_level].h_valid)
/* Did not attempt to generate a packet for this EL. */
continue;
if (pkt[enc_level].h.bytes_appended == 0)
/* Nothing was generated for this EL, so skip. */
continue;
rc = txp_pkt_commit(txp, &pkt[enc_level], archetype,
&txpim_pkt_reffed);
if (rc) {
status->sent_ack_eliciting
= status->sent_ack_eliciting
|| pkt[enc_level].tpkt->ackm_pkt.is_ack_eliciting;
if (enc_level == QUIC_ENC_LEVEL_HANDSHAKE)
status->sent_handshake
= (pkt[enc_level].h_valid
&& pkt[enc_level].h.bytes_appended > 0);
}
if (txpim_pkt_reffed)
pkt[enc_level].tpkt = NULL; /* don't free */
if (!rc)
goto out;
++pkts_done;
}
/* Flush & Cleanup */
res = 1;
out:
ossl_qtx_finish_dgram(txp->args.qtx);
for (enc_level = QUIC_ENC_LEVEL_INITIAL;
enc_level < QUIC_ENC_LEVEL_NUM;
++enc_level)
txp_pkt_cleanup(&pkt[enc_level], txp);
status->sent_pkt = pkts_done;
return res;
}
static const struct archetype_data archetypes[QUIC_ENC_LEVEL_NUM][TX_PACKETISER_ARCHETYPE_NUM] = {
/* EL 0(INITIAL) */
{
/* EL 0(INITIAL) - Archetype 0(NORMAL) */
{
/*allow_ack =*/ 1,
/*allow_ping =*/ 1,
/*allow_crypto =*/ 1,
/*allow_handshake_done =*/ 0,
/*allow_path_challenge =*/ 0,
/*allow_path_response =*/ 0,
/*allow_new_conn_id =*/ 0,
/*allow_retire_conn_id =*/ 0,
/*allow_stream_rel =*/ 0,
/*allow_conn_fc =*/ 0,
/*allow_conn_close =*/ 1,
/*allow_cfq_other =*/ 0,
/*allow_new_token =*/ 0,
/*allow_force_ack_eliciting =*/ 1,
/*allow_padding =*/ 1,
/*require_ack_eliciting =*/ 0,
/*bypass_cc =*/ 0,
},
/* EL 0(INITIAL) - Archetype 1(PROBE) */
{
/*allow_ack =*/ 1,
/*allow_ping =*/ 1,
/*allow_crypto =*/ 1,
/*allow_handshake_done =*/ 0,
/*allow_path_challenge =*/ 0,
/*allow_path_response =*/ 0,
/*allow_new_conn_id =*/ 0,
/*allow_retire_conn_id =*/ 0,
/*allow_stream_rel =*/ 0,
/*allow_conn_fc =*/ 0,
/*allow_conn_close =*/ 1,
/*allow_cfq_other =*/ 0,
/*allow_new_token =*/ 0,
/*allow_force_ack_eliciting =*/ 1,
/*allow_padding =*/ 1,
/*require_ack_eliciting =*/ 1,
/*bypass_cc =*/ 1,
},
/* EL 0(INITIAL) - Archetype 2(ACK_ONLY) */
{
/*allow_ack =*/ 1,
/*allow_ping =*/ 0,
/*allow_crypto =*/ 0,
/*allow_handshake_done =*/ 0,
/*allow_path_challenge =*/ 0,
/*allow_path_response =*/ 0,
/*allow_new_conn_id =*/ 0,
/*allow_retire_conn_id =*/ 0,
/*allow_stream_rel =*/ 0,
/*allow_conn_fc =*/ 0,
/*allow_conn_close =*/ 0,
/*allow_cfq_other =*/ 0,
/*allow_new_token =*/ 0,
/*allow_force_ack_eliciting =*/ 1,
/*allow_padding =*/ 0,
/*require_ack_eliciting =*/ 0,
/*bypass_cc =*/ 1,
},
},
/* EL 1(HANDSHAKE) */
{
/* EL 1(HANDSHAKE) - Archetype 0(NORMAL) */
{
/*allow_ack =*/ 1,
/*allow_ping =*/ 1,
/*allow_crypto =*/ 1,
/*allow_handshake_done =*/ 0,
/*allow_path_challenge =*/ 0,
/*allow_path_response =*/ 0,
/*allow_new_conn_id =*/ 0,
/*allow_retire_conn_id =*/ 0,
/*allow_stream_rel =*/ 0,
/*allow_conn_fc =*/ 0,
/*allow_conn_close =*/ 1,
/*allow_cfq_other =*/ 0,
/*allow_new_token =*/ 0,
/*allow_force_ack_eliciting =*/ 1,
/*allow_padding =*/ 1,
/*require_ack_eliciting =*/ 0,
/*bypass_cc =*/ 0,
},
/* EL 1(HANDSHAKE) - Archetype 1(PROBE) */
{
/*allow_ack =*/ 1,
/*allow_ping =*/ 1,
/*allow_crypto =*/ 1,
/*allow_handshake_done =*/ 0,
/*allow_path_challenge =*/ 0,
/*allow_path_response =*/ 0,
/*allow_new_conn_id =*/ 0,
/*allow_retire_conn_id =*/ 0,
/*allow_stream_rel =*/ 0,
/*allow_conn_fc =*/ 0,
/*allow_conn_close =*/ 1,
/*allow_cfq_other =*/ 0,
/*allow_new_token =*/ 0,
/*allow_force_ack_eliciting =*/ 1,
/*allow_padding =*/ 1,
/*require_ack_eliciting =*/ 1,
/*bypass_cc =*/ 1,
},
/* EL 1(HANDSHAKE) - Archetype 2(ACK_ONLY) */
{
/*allow_ack =*/ 1,
/*allow_ping =*/ 0,
/*allow_crypto =*/ 0,
/*allow_handshake_done =*/ 0,
/*allow_path_challenge =*/ 0,
/*allow_path_response =*/ 0,
/*allow_new_conn_id =*/ 0,
/*allow_retire_conn_id =*/ 0,
/*allow_stream_rel =*/ 0,
/*allow_conn_fc =*/ 0,
/*allow_conn_close =*/ 0,
/*allow_cfq_other =*/ 0,
/*allow_new_token =*/ 0,
/*allow_force_ack_eliciting =*/ 1,
/*allow_padding =*/ 0,
/*require_ack_eliciting =*/ 0,
/*bypass_cc =*/ 1,
},
},
/* EL 2(0RTT) */
{
/* EL 2(0RTT) - Archetype 0(NORMAL) */
{
/*allow_ack =*/ 0,
/*allow_ping =*/ 1,
/*allow_crypto =*/ 0,
/*allow_handshake_done =*/ 0,
/*allow_path_challenge =*/ 0,
/*allow_path_response =*/ 0,
/*allow_new_conn_id =*/ 1,
/*allow_retire_conn_id =*/ 1,
/*allow_stream_rel =*/ 1,
/*allow_conn_fc =*/ 1,
/*allow_conn_close =*/ 1,
/*allow_cfq_other =*/ 0,
/*allow_new_token =*/ 0,
/*allow_force_ack_eliciting =*/ 0,
/*allow_padding =*/ 1,
/*require_ack_eliciting =*/ 0,
/*bypass_cc =*/ 0,
},
/* EL 2(0RTT) - Archetype 1(PROBE) */
{
/*allow_ack =*/ 0,
/*allow_ping =*/ 1,
/*allow_crypto =*/ 0,
/*allow_handshake_done =*/ 0,
/*allow_path_challenge =*/ 0,
/*allow_path_response =*/ 0,
/*allow_new_conn_id =*/ 1,
/*allow_retire_conn_id =*/ 1,
/*allow_stream_rel =*/ 1,
/*allow_conn_fc =*/ 1,
/*allow_conn_close =*/ 1,
/*allow_cfq_other =*/ 0,
/*allow_new_token =*/ 0,
/*allow_force_ack_eliciting =*/ 0,
/*allow_padding =*/ 1,
/*require_ack_eliciting =*/ 1,
/*bypass_cc =*/ 1,
},
/* EL 2(0RTT) - Archetype 2(ACK_ONLY) */
{
/*allow_ack =*/ 0,
/*allow_ping =*/ 0,
/*allow_crypto =*/ 0,
/*allow_handshake_done =*/ 0,
/*allow_path_challenge =*/ 0,
/*allow_path_response =*/ 0,
/*allow_new_conn_id =*/ 0,
/*allow_retire_conn_id =*/ 0,
/*allow_stream_rel =*/ 0,
/*allow_conn_fc =*/ 0,
/*allow_conn_close =*/ 0,
/*allow_cfq_other =*/ 0,
/*allow_new_token =*/ 0,
/*allow_force_ack_eliciting =*/ 0,
/*allow_padding =*/ 0,
/*require_ack_eliciting =*/ 0,
/*bypass_cc =*/ 1,
},
},
/* EL 3(1RTT) */
{
/* EL 3(1RTT) - Archetype 0(NORMAL) */
{
/*allow_ack =*/ 1,
/*allow_ping =*/ 1,
/*allow_crypto =*/ 1,
/*allow_handshake_done =*/ 1,
/*allow_path_challenge =*/ 0,
/*allow_path_response =*/ 1,
/*allow_new_conn_id =*/ 1,
/*allow_retire_conn_id =*/ 1,
/*allow_stream_rel =*/ 1,
/*allow_conn_fc =*/ 1,
/*allow_conn_close =*/ 1,
/*allow_cfq_other =*/ 1,
/*allow_new_token =*/ 1,
/*allow_force_ack_eliciting =*/ 1,
/*allow_padding =*/ 1,
/*require_ack_eliciting =*/ 0,
/*bypass_cc =*/ 0,
},
/* EL 3(1RTT) - Archetype 1(PROBE) */
{
/*allow_ack =*/ 1,
/*allow_ping =*/ 1,
/*allow_crypto =*/ 1,
/*allow_handshake_done =*/ 1,
/*allow_path_challenge =*/ 0,
/*allow_path_response =*/ 1,
/*allow_new_conn_id =*/ 1,
/*allow_retire_conn_id =*/ 1,
/*allow_stream_rel =*/ 1,
/*allow_conn_fc =*/ 1,
/*allow_conn_close =*/ 1,
/*allow_cfq_other =*/ 1,
/*allow_new_token =*/ 1,
/*allow_force_ack_eliciting =*/ 1,
/*allow_padding =*/ 1,
/*require_ack_eliciting =*/ 1,
/*bypass_cc =*/ 1,
},
/* EL 3(1RTT) - Archetype 2(ACK_ONLY) */
{
/*allow_ack =*/ 1,
/*allow_ping =*/ 0,
/*allow_crypto =*/ 0,
/*allow_handshake_done =*/ 0,
/*allow_path_challenge =*/ 0,
/*allow_path_response =*/ 0,
/*allow_new_conn_id =*/ 0,
/*allow_retire_conn_id =*/ 0,
/*allow_stream_rel =*/ 0,
/*allow_conn_fc =*/ 0,
/*allow_conn_close =*/ 0,
/*allow_cfq_other =*/ 0,
/*allow_new_token =*/ 0,
/*allow_force_ack_eliciting =*/ 1,
/*allow_padding =*/ 0,
/*require_ack_eliciting =*/ 0,
/*bypass_cc =*/ 1,
}
}
};
static int txp_get_archetype_data(uint32_t enc_level,
uint32_t archetype,
struct archetype_data *a)
{
if (enc_level >= QUIC_ENC_LEVEL_NUM
|| archetype >= TX_PACKETISER_ARCHETYPE_NUM)
return 0;
/* No need to avoid copying this as it should not exceed one int in size. */
*a = archetypes[enc_level][archetype];
return 1;
}
static int txp_determine_geometry(OSSL_QUIC_TX_PACKETISER *txp,
uint32_t archetype,
uint32_t enc_level,
size_t running_total,
QUIC_PKT_HDR *phdr,
struct txp_pkt_geom *geom)
{
size_t mdpl, cmpl, hdr_len;
/* Get information about packet archetype. */
if (!txp_get_archetype_data(enc_level, archetype, &geom->adata))
return 0;
/* Assemble packet header. */
phdr->type = ossl_quic_enc_level_to_pkt_type(enc_level);
phdr->spin_bit = 0;
phdr->pn_len = txp_determine_pn_len(txp);
phdr->partial = 0;
phdr->fixed = 1;
phdr->reserved = 0;
phdr->version = QUIC_VERSION_1;
phdr->dst_conn_id = txp->args.cur_dcid;
phdr->src_conn_id = txp->args.cur_scid;
/*
* We need to know the length of the payload to get an accurate header
* length for non-1RTT packets, because the Length field found in
* Initial/Handshake/0-RTT packets uses a variable-length encoding. However,
* we don't have a good idea of the length of our payload, because the
* length of the payload depends on the room in the datagram after fitting
* the header, which depends on the size of the header.
*
* In general, it does not matter if a packet is slightly shorter (because
* e.g. we predicted use of a 2-byte length field, but ended up only needing
* a 1-byte length field). However this does matter for Initial packets
* which must be at least 1200 bytes, which is also the assumed default MTU;
* therefore in many cases Initial packets will be padded to 1200 bytes,
* which means if we overestimated the header size, we will be short by a
* few bytes and the server will ignore the packet for being too short. In
* this case, however, such packets always *will* be padded to meet 1200
* bytes, which requires a 2-byte length field, so we don't actually need to
* worry about this. Thus we estimate the header length assuming a 2-byte
* length field here, which should in practice work well in all cases.
*/
phdr->len = OSSL_QUIC_VLINT_2B_MAX - phdr->pn_len;
if (enc_level == QUIC_ENC_LEVEL_INITIAL) {
phdr->token = txp->initial_token;
phdr->token_len = txp->initial_token_len;
} else {
phdr->token = NULL;
phdr->token_len = 0;
}
hdr_len = ossl_quic_wire_get_encoded_pkt_hdr_len(phdr->dst_conn_id.id_len,
phdr);
if (hdr_len == 0)
return 0;
/* MDPL: Maximum datagram payload length. */
mdpl = txp_get_mdpl(txp);
/*
* CMPL: Maximum encoded packet size we can put into this datagram given any
* previous packets coalesced into it.
*/
if (running_total > mdpl)
/* Should not be possible, but if it happens: */
cmpl = 0;
else
cmpl = mdpl - running_total;
/* CMPPL: Maximum amount we can put into the current packet payload */
if (!txp_determine_ppl_from_pl(txp, cmpl, enc_level, hdr_len, &geom->cmppl))
return 0;
geom->cmpl = cmpl;
geom->pkt_overhead = cmpl - geom->cmppl;
geom->archetype = archetype;
return 1;
}
static uint32_t txp_determine_archetype(OSSL_QUIC_TX_PACKETISER *txp,
uint64_t cc_limit)
{
OSSL_ACKM_PROBE_INFO *probe_info
= ossl_ackm_get0_probe_request(txp->args.ackm);
uint32_t pn_space;
/*
* If ACKM has requested probe generation (e.g. due to PTO), we generate a
* Probe-archetype packet. Actually, we determine archetype on a
* per-datagram basis, so if any EL wants a probe, do a pass in which
* we try and generate a probe (if needed) for all ELs.
*/
if (probe_info->anti_deadlock_initial > 0
|| probe_info->anti_deadlock_handshake > 0)
return TX_PACKETISER_ARCHETYPE_PROBE;
for (pn_space = QUIC_PN_SPACE_INITIAL;
pn_space < QUIC_PN_SPACE_NUM;
++pn_space)
if (probe_info->pto[pn_space] > 0)
return TX_PACKETISER_ARCHETYPE_PROBE;
/*
* If we are out of CC budget, we cannot send a normal packet,
* but we can do an ACK-only packet (potentially, if we
* want to send an ACK).
*/
if (cc_limit == 0)
return TX_PACKETISER_ARCHETYPE_ACK_ONLY;
/* All other packets. */
return TX_PACKETISER_ARCHETYPE_NORMAL;
}
static int txp_should_try_staging(OSSL_QUIC_TX_PACKETISER *txp,
uint32_t enc_level,
uint32_t archetype,
uint64_t cc_limit,
uint32_t *conn_close_enc_level)
{
struct archetype_data a;
uint32_t pn_space = ossl_quic_enc_level_to_pn_space(enc_level);
QUIC_CFQ_ITEM *cfq_item;
if (!ossl_qtx_is_enc_level_provisioned(txp->args.qtx, enc_level))
return 0;
if (!txp_get_archetype_data(enc_level, archetype, &a))
return 0;
if (!a.bypass_cc && cc_limit == 0)
/* CC not allowing us to send. */
return 0;
/*
* We can produce CONNECTION_CLOSE frames on any EL in principle, which
* means we need to choose which EL we would prefer to use. After a
* connection is fully established we have only one provisioned EL and this
* is a non-issue. Where multiple ELs are provisioned, it is possible the
* peer does not have the keys for the EL yet, which suggests in general it
* is preferable to use the lowest EL which is still provisioned.
*
* However (RFC 9000 s. 10.2.3 & 12.5) we are also required to not send
* application CONNECTION_CLOSE frames in non-1-RTT ELs, so as to not
* potentially leak application data on a connection which has yet to be
* authenticated. Thus when we have an application CONNECTION_CLOSE frame
* queued and need to send it on a non-1-RTT EL, we have to convert it
* into a transport CONNECTION_CLOSE frame which contains no application
* data. Since this loses information, it suggests we should use the 1-RTT
* EL to avoid this if possible, even if a lower EL is also available.
*
* At the same time, just because we have the 1-RTT EL provisioned locally
* does not necessarily mean the peer does, for example if a handshake
* CRYPTO frame has been lost. It is fairly important that CONNECTION_CLOSE
* is signalled in a way we know our peer can decrypt, as we stop processing
* connection retransmission logic for real after connection close and
* simply 'blindly' retransmit the same CONNECTION_CLOSE frame.
*
* This is not a major concern for clients, since if a client has a 1-RTT EL
* provisioned the server is guaranteed to also have a 1-RTT EL provisioned.
*
* TODO(QUIC SERVER): Revisit this when server support is added.
*/
if (*conn_close_enc_level > enc_level
&& *conn_close_enc_level != QUIC_ENC_LEVEL_1RTT)
*conn_close_enc_level = enc_level;
/* Do we need to send a PTO probe? */
if (a.allow_force_ack_eliciting) {
OSSL_ACKM_PROBE_INFO *probe_info
= ossl_ackm_get0_probe_request(txp->args.ackm);
if ((enc_level == QUIC_ENC_LEVEL_INITIAL
&& probe_info->anti_deadlock_initial > 0)
|| (enc_level == QUIC_ENC_LEVEL_HANDSHAKE
&& probe_info->anti_deadlock_handshake > 0)
|| probe_info->pto[pn_space] > 0)
return 1;
}
/* Does the crypto stream for this EL want to produce anything? */
if (a.allow_crypto && sstream_is_pending(txp->args.crypto[pn_space]))
return 1;
/* Does the ACKM for this PN space want to produce anything? */
if (a.allow_ack && (ossl_ackm_is_ack_desired(txp->args.ackm, pn_space)
|| (txp->want_ack & (1UL << pn_space)) != 0))
return 1;
/* Do we need to force emission of an ACK-eliciting packet? */
if (a.allow_force_ack_eliciting
&& (txp->force_ack_eliciting & (1UL << pn_space)) != 0)
return 1;
/* Does the connection-level RXFC want to produce a frame? */
if (a.allow_conn_fc && (txp->want_max_data
|| ossl_quic_rxfc_has_cwm_changed(txp->args.conn_rxfc, 0)))
return 1;
/* Do we want to produce a MAX_STREAMS frame? */
if (a.allow_conn_fc
&& (txp->want_max_streams_bidi
|| ossl_quic_rxfc_has_cwm_changed(txp->args.max_streams_bidi_rxfc,
0)
|| txp->want_max_streams_uni
|| ossl_quic_rxfc_has_cwm_changed(txp->args.max_streams_uni_rxfc,
0)))
return 1;
/* Do we want to produce a HANDSHAKE_DONE frame? */
if (a.allow_handshake_done && txp->want_handshake_done)
return 1;
/* Do we want to produce a CONNECTION_CLOSE frame? */
if (a.allow_conn_close && txp->want_conn_close &&
*conn_close_enc_level == enc_level)
/*
* This is a bit of a special case since CONNECTION_CLOSE can appear in
* most packet types, and when we decide we want to send it this status
* isn't tied to a specific EL. So if we want to send it, we send it
* only on the lowest non-dropped EL.
*/
return 1;
/* Does the CFQ have any frames queued for this PN space? */
if (enc_level != QUIC_ENC_LEVEL_0RTT)
for (cfq_item = ossl_quic_cfq_get_priority_head(txp->args.cfq, pn_space);
cfq_item != NULL;
cfq_item = ossl_quic_cfq_item_get_priority_next(cfq_item, pn_space)) {
uint64_t frame_type = ossl_quic_cfq_item_get_frame_type(cfq_item);
switch (frame_type) {
case OSSL_QUIC_FRAME_TYPE_NEW_CONN_ID:
if (a.allow_new_conn_id)
return 1;
break;
case OSSL_QUIC_FRAME_TYPE_RETIRE_CONN_ID:
if (a.allow_retire_conn_id)
return 1;
break;
case OSSL_QUIC_FRAME_TYPE_NEW_TOKEN:
if (a.allow_new_token)
return 1;
break;
case OSSL_QUIC_FRAME_TYPE_PATH_RESPONSE:
if (a.allow_path_response)
return 1;
break;
default:
if (a.allow_cfq_other)
return 1;
break;
}
}
if (a.allow_stream_rel && txp->handshake_complete) {
QUIC_STREAM_ITER it;
/* If there are any active streams, 0/1-RTT wants to produce a packet.
* Whether a stream is on the active list is required to be precise
* (i.e., a stream is never on the active list if we cannot produce a
* frame for it), and all stream-related frames are governed by
* a.allow_stream_rel (i.e., if we can send one type of stream-related
* frame, we can send any of them), so we don't need to inspect
* individual streams on the active list, just confirm that the active
* list is non-empty.
*/
ossl_quic_stream_iter_init(&it, txp->args.qsm, 0);
if (it.stream != NULL)
return 1;
}
return 0;
}
static int sstream_is_pending(QUIC_SSTREAM *sstream)
{
OSSL_QUIC_FRAME_STREAM hdr;
OSSL_QTX_IOVEC iov[2];
size_t num_iov = OSSL_NELEM(iov);
return ossl_quic_sstream_get_stream_frame(sstream, 0, &hdr, iov, &num_iov);
}
/* Determine how many bytes we should use for the encoded PN. */
static size_t txp_determine_pn_len(OSSL_QUIC_TX_PACKETISER *txp)
{
return 4; /* TODO(QUIC FUTURE) */
}
/* Determine plaintext packet payload length from payload length. */
static int txp_determine_ppl_from_pl(OSSL_QUIC_TX_PACKETISER *txp,
size_t pl,
uint32_t enc_level,
size_t hdr_len,
size_t *r)
{
if (pl < hdr_len)
return 0;
pl -= hdr_len;
if (!ossl_qtx_calculate_plaintext_payload_len(txp->args.qtx, enc_level,
pl, &pl))
return 0;
*r = pl;
return 1;
}
static size_t txp_get_mdpl(OSSL_QUIC_TX_PACKETISER *txp)
{
return ossl_qtx_get_mdpl(txp->args.qtx);
}
static QUIC_SSTREAM *get_sstream_by_id(uint64_t stream_id, uint32_t pn_space,
void *arg)
{
OSSL_QUIC_TX_PACKETISER *txp = arg;
QUIC_STREAM *s;
if (stream_id == UINT64_MAX)
return txp->args.crypto[pn_space];
s = ossl_quic_stream_map_get_by_id(txp->args.qsm, stream_id);
if (s == NULL)
return NULL;
return s->sstream;
}
static void on_regen_notify(uint64_t frame_type, uint64_t stream_id,
QUIC_TXPIM_PKT *pkt, void *arg)
{
OSSL_QUIC_TX_PACKETISER *txp = arg;
switch (frame_type) {
case OSSL_QUIC_FRAME_TYPE_HANDSHAKE_DONE:
txp->want_handshake_done = 1;
break;
case OSSL_QUIC_FRAME_TYPE_MAX_DATA:
txp->want_max_data = 1;
break;
case OSSL_QUIC_FRAME_TYPE_MAX_STREAMS_BIDI:
txp->want_max_streams_bidi = 1;
break;
case OSSL_QUIC_FRAME_TYPE_MAX_STREAMS_UNI:
txp->want_max_streams_uni = 1;
break;
case OSSL_QUIC_FRAME_TYPE_ACK_WITH_ECN:
txp->want_ack |= (1UL << pkt->ackm_pkt.pkt_space);
break;
case OSSL_QUIC_FRAME_TYPE_MAX_STREAM_DATA:
{
QUIC_STREAM *s
= ossl_quic_stream_map_get_by_id(txp->args.qsm, stream_id);
if (s == NULL)
return;
s->want_max_stream_data = 1;
ossl_quic_stream_map_update_state(txp->args.qsm, s);
}
break;
case OSSL_QUIC_FRAME_TYPE_STOP_SENDING:
{
QUIC_STREAM *s
= ossl_quic_stream_map_get_by_id(txp->args.qsm, stream_id);
if (s == NULL)
return;
ossl_quic_stream_map_schedule_stop_sending(txp->args.qsm, s);
}
break;
case OSSL_QUIC_FRAME_TYPE_RESET_STREAM:
{
QUIC_STREAM *s
= ossl_quic_stream_map_get_by_id(txp->args.qsm, stream_id);
if (s == NULL)
return;
s->want_reset_stream = 1;
ossl_quic_stream_map_update_state(txp->args.qsm, s);
}
break;
default:
assert(0);
break;
}
}
static int txp_pkt_init(struct txp_pkt *pkt, OSSL_QUIC_TX_PACKETISER *txp,
uint32_t enc_level, uint32_t archetype,
size_t running_total)
{
if (!txp_determine_geometry(txp, archetype, enc_level,
running_total, &pkt->phdr, &pkt->geom))
return 0;
/*
* Initialise TX helper. If we must be ACK eliciting, reserve 1 byte for
* PING.
*/
if (!tx_helper_init(&pkt->h, txp, enc_level,
pkt->geom.cmppl,
pkt->geom.adata.require_ack_eliciting ? 1 : 0))
return 0;
pkt->h_valid = 1;
pkt->tpkt = NULL;
pkt->stream_head = NULL;
pkt->force_pad = 0;
return 1;
}
static void txp_pkt_cleanup(struct txp_pkt *pkt, OSSL_QUIC_TX_PACKETISER *txp)
{
if (!pkt->h_valid)
return;
tx_helper_cleanup(&pkt->h);
pkt->h_valid = 0;
if (pkt->tpkt != NULL) {
ossl_quic_txpim_pkt_release(txp->args.txpim, pkt->tpkt);
pkt->tpkt = NULL;
}
}
static int txp_pkt_postgen_update_pkt_overhead(struct txp_pkt *pkt,
OSSL_QUIC_TX_PACKETISER *txp)
{
/*
* After we have staged and generated our packets, but before we commit
* them, it is possible for the estimated packet overhead (packet header +
* AEAD tag size) to shrink slightly because we generated a short packet
* whose which can be represented in fewer bytes as a variable-length
* integer than we were (pessimistically) budgeting for. We need to account
* for this to ensure that we get our padding calculation exactly right.
*
* Update pkt_overhead to be accurate now that we know how much data is
* going in a packet.
*/
size_t hdr_len, ciphertext_len;
if (pkt->h.enc_level == QUIC_ENC_LEVEL_INITIAL)
/*
* Don't update overheads for the INITIAL EL - we have not finished
* appending padding to it and would potentially miscalculate the
* correct padding if we now update the pkt_overhead field to switch to
* e.g. a 1-byte length field in the packet header. Since we are padding
* to QUIC_MIN_INITIAL_DGRAM_LEN which requires a 2-byte length field,
* this is guaranteed to be moot anyway. See comment in
* txp_determine_geometry for more information.
*/
return 1;
if (!ossl_qtx_calculate_ciphertext_payload_len(txp->args.qtx, pkt->h.enc_level,
pkt->h.bytes_appended,
&ciphertext_len))
return 0;
pkt->phdr.len = ciphertext_len;
hdr_len = ossl_quic_wire_get_encoded_pkt_hdr_len(pkt->phdr.dst_conn_id.id_len,
&pkt->phdr);
pkt->geom.pkt_overhead = hdr_len + ciphertext_len - pkt->h.bytes_appended;
return 1;
}
static void on_confirm_notify(uint64_t frame_type, uint64_t stream_id,
QUIC_TXPIM_PKT *pkt, void *arg)
{
OSSL_QUIC_TX_PACKETISER *txp = arg;
switch (frame_type) {
case OSSL_QUIC_FRAME_TYPE_STOP_SENDING:
{
QUIC_STREAM *s
= ossl_quic_stream_map_get_by_id(txp->args.qsm, stream_id);
if (s == NULL)
return;
s->acked_stop_sending = 1;
ossl_quic_stream_map_update_state(txp->args.qsm, s);
}
break;
case OSSL_QUIC_FRAME_TYPE_RESET_STREAM:
{
QUIC_STREAM *s
= ossl_quic_stream_map_get_by_id(txp->args.qsm, stream_id);
if (s == NULL)
return;
/*
* We must already be in RESET_SENT or RESET_RECVD if we are
* here, so we don't need to check state here.
*/
ossl_quic_stream_map_notify_reset_stream_acked(txp->args.qsm, s);
ossl_quic_stream_map_update_state(txp->args.qsm, s);
}
break;
default:
assert(0);
break;
}
}
static int txp_pkt_append_padding(struct txp_pkt *pkt,
OSSL_QUIC_TX_PACKETISER *txp, size_t num_bytes)
{
WPACKET *wpkt;
if (num_bytes == 0)
return 1;
if (!ossl_assert(pkt->h_valid))
return 0;
if (!ossl_assert(pkt->tpkt != NULL))
return 0;
wpkt = tx_helper_begin(&pkt->h);
if (wpkt == NULL)
return 0;
if (!ossl_quic_wire_encode_padding(wpkt, num_bytes)) {
tx_helper_rollback(&pkt->h);
return 0;
}
if (!tx_helper_commit(&pkt->h))
return 0;
pkt->tpkt->ackm_pkt.num_bytes += num_bytes;
/* Cannot be non-inflight if we have a PADDING frame */
pkt->tpkt->ackm_pkt.is_inflight = 1;
return 1;
}
static void on_sstream_updated(uint64_t stream_id, void *arg)
{
OSSL_QUIC_TX_PACKETISER *txp = arg;
QUIC_STREAM *s;
s = ossl_quic_stream_map_get_by_id(txp->args.qsm, stream_id);
if (s == NULL)
return;
ossl_quic_stream_map_update_state(txp->args.qsm, s);
}
/*
* Returns 1 if we can send that many bytes in closing state, 0 otherwise.
* Also maintains the bytes sent state if it returns a success.
*/
static int try_commit_conn_close(OSSL_QUIC_TX_PACKETISER *txp, size_t n)
{
int res;
/* We can always send the first connection close frame */
if (txp->closing_bytes_recv == 0)
return 1;
/*
* RFC 9000 s. 10.2.1 Closing Connection State:
* To avoid being used for an amplification attack, such
* endpoints MUST limit the cumulative size of packets it sends
* to three times the cumulative size of the packets that are
* received and attributed to the connection.
* and:
* An endpoint in the closing state MUST either discard packets
* received from an unvalidated address or limit the cumulative
* size of packets it sends to an unvalidated address to three
* times the size of packets it receives from that address.
*/
res = txp->closing_bytes_xmit + n <= txp->closing_bytes_recv * 3;
/*
* Attribute the bytes to the connection, if we are allowed to send them
* and this isn't the first closing frame.
*/
if (res && txp->closing_bytes_recv != 0)
txp->closing_bytes_xmit += n;
return res;
}
void ossl_quic_tx_packetiser_record_received_closing_bytes(
OSSL_QUIC_TX_PACKETISER *txp, size_t n)
{
txp->closing_bytes_recv += n;
}
static int txp_generate_pre_token(OSSL_QUIC_TX_PACKETISER *txp,
struct txp_pkt *pkt,
int chosen_for_conn_close,
int *can_be_non_inflight)
{
const uint32_t enc_level = pkt->h.enc_level;
const uint32_t pn_space = ossl_quic_enc_level_to_pn_space(enc_level);
const struct archetype_data *a = &pkt->geom.adata;
QUIC_TXPIM_PKT *tpkt = pkt->tpkt;
struct tx_helper *h = &pkt->h;
const OSSL_QUIC_FRAME_ACK *ack;
OSSL_QUIC_FRAME_ACK ack2;
tpkt->ackm_pkt.largest_acked = QUIC_PN_INVALID;
/* ACK Frames (Regenerate) */
if (a->allow_ack
&& tx_helper_get_space_left(h) >= MIN_FRAME_SIZE_ACK
&& (((txp->want_ack & (1UL << pn_space)) != 0)
|| ossl_ackm_is_ack_desired(txp->args.ackm, pn_space))
&& (ack = ossl_ackm_get_ack_frame(txp->args.ackm, pn_space)) != NULL) {
WPACKET *wpkt = tx_helper_begin(h);
if (wpkt == NULL)
return 0;
/* We do not currently support ECN */
ack2 = *ack;
ack2.ecn_present = 0;
if (ossl_quic_wire_encode_frame_ack(wpkt,
txp->args.ack_delay_exponent,
&ack2)) {
if (!tx_helper_commit(h))
return 0;
tpkt->had_ack_frame = 1;
if (ack->num_ack_ranges > 0)
tpkt->ackm_pkt.largest_acked = ack->ack_ranges[0].end;
if (txp->ack_tx_cb != NULL)
txp->ack_tx_cb(&ack2, pn_space, txp->ack_tx_cb_arg);
} else {
tx_helper_rollback(h);
}
}
/* CONNECTION_CLOSE Frames (Regenerate) */
if (a->allow_conn_close && txp->want_conn_close && chosen_for_conn_close) {
WPACKET *wpkt = tx_helper_begin(h);
OSSL_QUIC_FRAME_CONN_CLOSE f, *pf = &txp->conn_close_frame;
size_t l;
if (wpkt == NULL)
return 0;
/*
* Application CONNECTION_CLOSE frames may only be sent in the
* Application PN space, as otherwise they may be sent before a
* connection is authenticated and leak application data. Therefore, if
* we need to send a CONNECTION_CLOSE frame in another PN space and were
* given an application CONNECTION_CLOSE frame, convert it into a
* transport CONNECTION_CLOSE frame, removing any sensitive application
* data.
*
* RFC 9000 s. 10.2.3: "A CONNECTION_CLOSE of type 0x1d MUST be replaced
* by a CONNECTION_CLOSE of type 0x1c when sending the frame in Initial
* or Handshake packets. Otherwise, information about the application
* state might be revealed. Endpoints MUST clear the value of the Reason
* Phrase field and SHOULD use the APPLICATION_ERROR code when
* converting to a CONNECTION_CLOSE of type 0x1c."
*/
if (pn_space != QUIC_PN_SPACE_APP && pf->is_app) {
pf = &f;
pf->is_app = 0;
pf->frame_type = 0;
pf->error_code = QUIC_ERR_APPLICATION_ERROR;
pf->reason = NULL;
pf->reason_len = 0;
}
if (ossl_quic_wire_encode_frame_conn_close(wpkt, pf)
&& WPACKET_get_total_written(wpkt, &l)
&& try_commit_conn_close(txp, l)) {
if (!tx_helper_commit(h))
return 0;
tpkt->had_conn_close = 1;
*can_be_non_inflight = 0;
} else {
tx_helper_rollback(h);
}
}
return 1;
}
static int try_len(size_t space_left, size_t orig_len,
size_t base_hdr_len, size_t lenbytes,
uint64_t maxn, size_t *hdr_len, size_t *payload_len)
{
size_t n;
size_t maxn_ = maxn > SIZE_MAX ? SIZE_MAX : (size_t)maxn;
*hdr_len = base_hdr_len + lenbytes;
if (orig_len == 0 && space_left >= *hdr_len) {
*payload_len = 0;
return 1;
}
n = orig_len;
if (n > maxn_)
n = maxn_;
if (n + *hdr_len > space_left)
n = (space_left >= *hdr_len) ? space_left - *hdr_len : 0;
*payload_len = n;
return n > 0;
}
static int determine_len(size_t space_left, size_t orig_len,
size_t base_hdr_len,
uint64_t *hlen, uint64_t *len)
{
int ok = 0;
size_t chosen_payload_len = 0;
size_t chosen_hdr_len = 0;
size_t payload_len[4], hdr_len[4];
int i, valid[4] = {0};
valid[0] = try_len(space_left, orig_len, base_hdr_len,
1, OSSL_QUIC_VLINT_1B_MAX,
&hdr_len[0], &payload_len[0]);
valid[1] = try_len(space_left, orig_len, base_hdr_len,
2, OSSL_QUIC_VLINT_2B_MAX,
&hdr_len[1], &payload_len[1]);
valid[2] = try_len(space_left, orig_len, base_hdr_len,
4, OSSL_QUIC_VLINT_4B_MAX,
&hdr_len[2], &payload_len[2]);
valid[3] = try_len(space_left, orig_len, base_hdr_len,
8, OSSL_QUIC_VLINT_8B_MAX,
&hdr_len[3], &payload_len[3]);
for (i = OSSL_NELEM(valid) - 1; i >= 0; --i)
if (valid[i] && payload_len[i] >= chosen_payload_len) {
chosen_payload_len = payload_len[i];
chosen_hdr_len = hdr_len[i];
ok = 1;
}
*hlen = chosen_hdr_len;
*len = chosen_payload_len;
return ok;
}
/*
* Given a CRYPTO frame header with accurate chdr->len and a budget
* (space_left), try to find the optimal value of chdr->len to fill as much of
* the budget as possible. This is slightly hairy because larger values of
* chdr->len cause larger encoded sizes of the length field of the frame, which
* in turn mean less space available for payload data. We check all possible
* encodings and choose the optimal encoding.
*/
static int determine_crypto_len(struct tx_helper *h,
OSSL_QUIC_FRAME_CRYPTO *chdr,
size_t space_left,
uint64_t *hlen,
uint64_t *len)
{
size_t orig_len;
size_t base_hdr_len; /* CRYPTO header length without length field */
if (chdr->len > SIZE_MAX)
return 0;
orig_len = (size_t)chdr->len;
chdr->len = 0;
base_hdr_len = ossl_quic_wire_get_encoded_frame_len_crypto_hdr(chdr);
chdr->len = orig_len;
if (base_hdr_len == 0)
return 0;
--base_hdr_len;
return determine_len(space_left, orig_len, base_hdr_len, hlen, len);
}
static int determine_stream_len(struct tx_helper *h,
OSSL_QUIC_FRAME_STREAM *shdr,
size_t space_left,
uint64_t *hlen,
uint64_t *len)
{
size_t orig_len;
size_t base_hdr_len; /* STREAM header length without length field */
if (shdr->len > SIZE_MAX)
return 0;
orig_len = (size_t)shdr->len;
shdr->len = 0;
base_hdr_len = ossl_quic_wire_get_encoded_frame_len_stream_hdr(shdr);
shdr->len = orig_len;
if (base_hdr_len == 0)
return 0;
if (shdr->has_explicit_len)
--base_hdr_len;
return determine_len(space_left, orig_len, base_hdr_len, hlen, len);
}
static int txp_generate_crypto_frames(OSSL_QUIC_TX_PACKETISER *txp,
struct txp_pkt *pkt,
int *have_ack_eliciting)
{
const uint32_t enc_level = pkt->h.enc_level;
const uint32_t pn_space = ossl_quic_enc_level_to_pn_space(enc_level);
QUIC_TXPIM_PKT *tpkt = pkt->tpkt;
struct tx_helper *h = &pkt->h;
size_t num_stream_iovec;
OSSL_QUIC_FRAME_STREAM shdr = {0};
OSSL_QUIC_FRAME_CRYPTO chdr = {0};
OSSL_QTX_IOVEC iov[2];
uint64_t hdr_bytes;
WPACKET *wpkt;
QUIC_TXPIM_CHUNK chunk = {0};
size_t i, space_left;
for (i = 0;; ++i) {
space_left = tx_helper_get_space_left(h);
if (space_left < MIN_FRAME_SIZE_CRYPTO)
return 1; /* no point trying */
/* Do we have any CRYPTO data waiting? */
num_stream_iovec = OSSL_NELEM(iov);
if (!ossl_quic_sstream_get_stream_frame(txp->args.crypto[pn_space],
i, &shdr, iov,
&num_stream_iovec))
return 1; /* nothing to do */
/* Convert STREAM frame header to CRYPTO frame header */
chdr.offset = shdr.offset;
chdr.len = shdr.len;
if (chdr.len == 0)
return 1; /* nothing to do */
/* Find best fit (header length, payload length) combination. */
if (!determine_crypto_len(h, &chdr, space_left, &hdr_bytes,
&chdr.len))
return 1; /* can't fit anything */
/*
* Truncate IOVs to match our chosen length.
*
* The length cannot be more than SIZE_MAX because this length comes
* from our send stream buffer.
*/
ossl_quic_sstream_adjust_iov((size_t)chdr.len, iov, num_stream_iovec);
/*
* Ensure we have enough iovecs allocated (1 for the header, up to 2 for
* the stream data.)
*/
if (!txp_el_ensure_iovec(&txp->el[enc_level], h->num_iovec + 3))
return 0; /* alloc error */
/* Encode the header. */
wpkt = tx_helper_begin(h);
if (wpkt == NULL)
return 0; /* alloc error */
if (!ossl_quic_wire_encode_frame_crypto_hdr(wpkt, &chdr)) {
tx_helper_rollback(h);
return 1; /* can't fit */
}
if (!tx_helper_commit(h))
return 0; /* alloc error */
/* Add payload iovecs to the helper (infallible). */
for (i = 0; i < num_stream_iovec; ++i)
tx_helper_append_iovec(h, iov[i].buf, iov[i].buf_len);
*have_ack_eliciting = 1;
tx_helper_unrestrict(h); /* no longer need PING */
/* Log chunk to TXPIM. */
chunk.stream_id = UINT64_MAX; /* crypto stream */
chunk.start = chdr.offset;
chunk.end = chdr.offset + chdr.len - 1;
chunk.has_fin = 0; /* Crypto stream never ends */
if (!ossl_quic_txpim_pkt_append_chunk(tpkt, &chunk))
return 0; /* alloc error */
}
}
struct chunk_info {
OSSL_QUIC_FRAME_STREAM shdr;
uint64_t orig_len;
OSSL_QTX_IOVEC iov[2];
size_t num_stream_iovec;
int valid;
};
static int txp_plan_stream_chunk(OSSL_QUIC_TX_PACKETISER *txp,
struct tx_helper *h,
QUIC_SSTREAM *sstream,
QUIC_TXFC *stream_txfc,
size_t skip,
struct chunk_info *chunk,
uint64_t consumed)
{
uint64_t fc_credit, fc_swm, fc_limit;
chunk->num_stream_iovec = OSSL_NELEM(chunk->iov);
chunk->valid = ossl_quic_sstream_get_stream_frame(sstream, skip,
&chunk->shdr,
chunk->iov,
&chunk->num_stream_iovec);
if (!chunk->valid)
return 1;
if (!ossl_assert(chunk->shdr.len > 0 || chunk->shdr.is_fin))
/* Should only have 0-length chunk if FIN */
return 0;
chunk->orig_len = chunk->shdr.len;
/* Clamp according to connection and stream-level TXFC. */
fc_credit = ossl_quic_txfc_get_credit(stream_txfc, consumed);
fc_swm = ossl_quic_txfc_get_swm(stream_txfc);
fc_limit = fc_swm + fc_credit;
if (chunk->shdr.len > 0 && chunk->shdr.offset + chunk->shdr.len > fc_limit) {
chunk->shdr.len = (fc_limit <= chunk->shdr.offset)
? 0 : fc_limit - chunk->shdr.offset;
chunk->shdr.is_fin = 0;
}
if (chunk->shdr.len == 0 && !chunk->shdr.is_fin) {
/*
* Nothing to do due to TXFC. Since SSTREAM returns chunks in ascending
* order of offset we don't need to check any later chunks, so stop
* iterating here.
*/
chunk->valid = 0;
return 1;
}
return 1;
}
/*
* Returns 0 on fatal error (e.g. allocation failure), 1 on success.
* *packet_full is set to 1 if there is no longer enough room for another STREAM
* frame.
*/
static int txp_generate_stream_frames(OSSL_QUIC_TX_PACKETISER *txp,
struct txp_pkt *pkt,
uint64_t id,
QUIC_SSTREAM *sstream,
QUIC_TXFC *stream_txfc,
QUIC_STREAM *next_stream,
int *have_ack_eliciting,
int *packet_full,
uint64_t *new_credit_consumed,
uint64_t conn_consumed)
{
int rc = 0;
struct chunk_info chunks[2] = {0};
const uint32_t enc_level = pkt->h.enc_level;
QUIC_TXPIM_PKT *tpkt = pkt->tpkt;
struct tx_helper *h = &pkt->h;
OSSL_QUIC_FRAME_STREAM *shdr;
WPACKET *wpkt;
QUIC_TXPIM_CHUNK chunk;
size_t i, j, space_left;
int can_fill_payload, use_explicit_len;
int could_have_following_chunk;
uint64_t orig_len;
uint64_t hdr_len_implicit, payload_len_implicit;
uint64_t hdr_len_explicit, payload_len_explicit;
uint64_t fc_swm, fc_new_hwm;
fc_swm = ossl_quic_txfc_get_swm(stream_txfc);
fc_new_hwm = fc_swm;
/*
* Load the first two chunks if any offered by the send stream. We retrieve
* the next chunk in advance so we can determine if we need to send any more
* chunks from the same stream after this one, which is needed when
* determining when we can use an implicit length in a STREAM frame.
*/
for (i = 0; i < 2; ++i) {
if (!txp_plan_stream_chunk(txp, h, sstream, stream_txfc, i, &chunks[i],
conn_consumed))
goto err;
if (i == 0 && !chunks[i].valid) {
/* No chunks, nothing to do. */
rc = 1;
goto err;
}
}
for (i = 0;; ++i) {
space_left = tx_helper_get_space_left(h);
if (!chunks[i % 2].valid) {
/* Out of chunks; we're done. */
rc = 1;
goto err;
}
if (space_left < MIN_FRAME_SIZE_STREAM) {
*packet_full = 1;
rc = 1;
goto err;
}
if (!ossl_assert(!h->done_implicit))
/*
* Logic below should have ensured we didn't append an
* implicit-length unless we filled the packet or didn't have
* another stream to handle, so this should not be possible.
*/
goto err;
shdr = &chunks[i % 2].shdr;
orig_len = chunks[i % 2].orig_len;
if (i > 0)
/* Load next chunk for lookahead. */
if (!txp_plan_stream_chunk(txp, h, sstream, stream_txfc, i + 1,
&chunks[(i + 1) % 2], conn_consumed))
goto err;
/*
* Find best fit (header length, payload length) combination for if we
* use an implicit length.
*/
shdr->has_explicit_len = 0;
hdr_len_implicit = payload_len_implicit = 0;
if (!determine_stream_len(h, shdr, space_left,
&hdr_len_implicit, &payload_len_implicit)) {
*packet_full = 1;
rc = 1;
goto err; /* can't fit anything */
}
/*
* If there is a next stream, we don't use the implicit length so we can
* add more STREAM frames after this one, unless there is enough data
* for this STREAM frame to fill the packet.
*/
can_fill_payload = (hdr_len_implicit + payload_len_implicit
>= space_left);
/*
* Is there is a stream after this one, or another chunk pending
* transmission in this stream?
*/
could_have_following_chunk
= (next_stream != NULL || chunks[(i + 1) % 2].valid);
/* Choose between explicit or implicit length representations. */
use_explicit_len = !((can_fill_payload || !could_have_following_chunk)
&& !pkt->force_pad);
if (use_explicit_len) {
/*
* Find best fit (header length, payload length) combination for if
* we use an explicit length.
*/
shdr->has_explicit_len = 1;
hdr_len_explicit = payload_len_explicit = 0;
if (!determine_stream_len(h, shdr, space_left,
&hdr_len_explicit, &payload_len_explicit)) {
*packet_full = 1;
rc = 1;
goto err; /* can't fit anything */
}
shdr->len = payload_len_explicit;
} else {
*packet_full = 1;
shdr->has_explicit_len = 0;
shdr->len = payload_len_implicit;
}
/* If this is a FIN, don't keep filling the packet with more FINs. */
if (shdr->is_fin)
chunks[(i + 1) % 2].valid = 0;
/*
* We are now committed to our length (shdr->len can't change).
* If we truncated the chunk, clear the FIN bit.
*/
if (shdr->len < orig_len)
shdr->is_fin = 0;
/* Truncate IOVs to match our chosen length. */
ossl_quic_sstream_adjust_iov((size_t)shdr->len, chunks[i % 2].iov,
chunks[i % 2].num_stream_iovec);
/*
* Ensure we have enough iovecs allocated (1 for the header, up to 2 for
* the stream data.)
*/
if (!txp_el_ensure_iovec(&txp->el[enc_level], h->num_iovec + 3))
goto err; /* alloc error */
/* Encode the header. */
wpkt = tx_helper_begin(h);
if (wpkt == NULL)
goto err; /* alloc error */
shdr->stream_id = id;
if (!ossl_assert(ossl_quic_wire_encode_frame_stream_hdr(wpkt, shdr))) {
/* (Should not be possible.) */
tx_helper_rollback(h);
*packet_full = 1;
rc = 1;
goto err; /* can't fit */
}
if (!tx_helper_commit(h))
goto err; /* alloc error */
/* Add payload iovecs to the helper (infallible). */
for (j = 0; j < chunks[i % 2].num_stream_iovec; ++j)
tx_helper_append_iovec(h, chunks[i % 2].iov[j].buf,
chunks[i % 2].iov[j].buf_len);
*have_ack_eliciting = 1;
tx_helper_unrestrict(h); /* no longer need PING */
if (!shdr->has_explicit_len)
h->done_implicit = 1;
/* Log new TXFC credit which was consumed. */
if (shdr->len > 0 && shdr->offset + shdr->len > fc_new_hwm)
fc_new_hwm = shdr->offset + shdr->len;
/* Log chunk to TXPIM. */
chunk.stream_id = shdr->stream_id;
chunk.start = shdr->offset;
chunk.end = shdr->offset + shdr->len - 1;
chunk.has_fin = shdr->is_fin;
chunk.has_stop_sending = 0;
chunk.has_reset_stream = 0;
if (!ossl_quic_txpim_pkt_append_chunk(tpkt, &chunk))
goto err; /* alloc error */
if (shdr->len < orig_len) {
/*
* If we did not serialize all of this chunk we definitely do not
* want to try the next chunk
*/
rc = 1;
goto err;
}
}
err:
*new_credit_consumed = fc_new_hwm - fc_swm;
return rc;
}
static void txp_enlink_tmp(QUIC_STREAM **tmp_head, QUIC_STREAM *stream)
{
stream->txp_next = *tmp_head;
*tmp_head = stream;
}
static int txp_generate_stream_related(OSSL_QUIC_TX_PACKETISER *txp,
struct txp_pkt *pkt,
int *have_ack_eliciting,
QUIC_STREAM **tmp_head)
{
QUIC_STREAM_ITER it;
WPACKET *wpkt;
uint64_t cwm;
QUIC_STREAM *stream, *snext;
struct tx_helper *h = &pkt->h;
uint64_t conn_consumed = 0;
for (ossl_quic_stream_iter_init(&it, txp->args.qsm, 1);
it.stream != NULL;) {
stream = it.stream;
ossl_quic_stream_iter_next(&it);
snext = it.stream;
stream->txp_sent_fc = 0;
stream->txp_sent_stop_sending = 0;
stream->txp_sent_reset_stream = 0;
stream->txp_blocked = 0;
stream->txp_txfc_new_credit_consumed = 0;
/* Stream Abort Frames (STOP_SENDING, RESET_STREAM) */
if (stream->want_stop_sending) {
OSSL_QUIC_FRAME_STOP_SENDING f;
wpkt = tx_helper_begin(h);
if (wpkt == NULL)
return 0; /* alloc error */
f.stream_id = stream->id;
f.app_error_code = stream->stop_sending_aec;
if (!ossl_quic_wire_encode_frame_stop_sending(wpkt, &f)) {
tx_helper_rollback(h); /* can't fit */
txp_enlink_tmp(tmp_head, stream);
break;
}
if (!tx_helper_commit(h))
return 0; /* alloc error */
*have_ack_eliciting = 1;
tx_helper_unrestrict(h); /* no longer need PING */
stream->txp_sent_stop_sending = 1;
}
if (stream->want_reset_stream) {
OSSL_QUIC_FRAME_RESET_STREAM f;
if (!ossl_assert(stream->send_state == QUIC_SSTREAM_STATE_RESET_SENT))
return 0;
wpkt = tx_helper_begin(h);
if (wpkt == NULL)
return 0; /* alloc error */
f.stream_id = stream->id;
f.app_error_code = stream->reset_stream_aec;
if (!ossl_quic_stream_send_get_final_size(stream, &f.final_size))
return 0; /* should not be possible */
if (!ossl_quic_wire_encode_frame_reset_stream(wpkt, &f)) {
tx_helper_rollback(h); /* can't fit */
txp_enlink_tmp(tmp_head, stream);
break;
}
if (!tx_helper_commit(h))
return 0; /* alloc error */
*have_ack_eliciting = 1;
tx_helper_unrestrict(h); /* no longer need PING */
stream->txp_sent_reset_stream = 1;
/*
* The final size of the stream as indicated by RESET_STREAM is used
* to ensure a consistent view of flow control state by both
* parties; if we happen to send a RESET_STREAM that consumes more
* flow control credit, make sure we account for that.
*/
if (!ossl_assert(f.final_size <= ossl_quic_txfc_get_swm(&stream->txfc)))
return 0;
stream->txp_txfc_new_credit_consumed
= f.final_size - ossl_quic_txfc_get_swm(&stream->txfc);
}
/*
* Stream Flow Control Frames (MAX_STREAM_DATA)
*
* RFC 9000 s. 13.3: "An endpoint SHOULD stop sending MAX_STREAM_DATA
* frames when the receiving part of the stream enters a "Size Known" or
* "Reset Recvd" state." -- In practice, RECV is the only state
* in which it makes sense to generate more MAX_STREAM_DATA frames.
*/
if (stream->recv_state == QUIC_RSTREAM_STATE_RECV
&& (stream->want_max_stream_data
|| ossl_quic_rxfc_has_cwm_changed(&stream->rxfc, 0))) {
wpkt = tx_helper_begin(h);
if (wpkt == NULL)
return 0; /* alloc error */
cwm = ossl_quic_rxfc_get_cwm(&stream->rxfc);
if (!ossl_quic_wire_encode_frame_max_stream_data(wpkt, stream->id,
cwm)) {
tx_helper_rollback(h); /* can't fit */
txp_enlink_tmp(tmp_head, stream);
break;
}
if (!tx_helper_commit(h))
return 0; /* alloc error */
*have_ack_eliciting = 1;
tx_helper_unrestrict(h); /* no longer need PING */
stream->txp_sent_fc = 1;
}
/*
* Stream Data Frames (STREAM)
*
* RFC 9000 s. 3.3: A sender MUST NOT send a STREAM [...] frame for a
* stream in the "Reset Sent" state [or any terminal state]. We don't
* send any more STREAM frames if we are sending, have sent, or are
* planning to send, RESET_STREAM. The other terminal state is Data
* Recvd, but txp_generate_stream_frames() is guaranteed to generate
* nothing in this case.
*/
if (ossl_quic_stream_has_send_buffer(stream)
&& !ossl_quic_stream_send_is_reset(stream)) {
int packet_full = 0;
if (!ossl_assert(!stream->want_reset_stream))
return 0;
if (!txp_generate_stream_frames(txp, pkt,
stream->id, stream->sstream,
&stream->txfc,
snext,
have_ack_eliciting,
&packet_full,
&stream->txp_txfc_new_credit_consumed,
conn_consumed)) {
/* Fatal error (allocation, etc.) */
txp_enlink_tmp(tmp_head, stream);
return 0;
}
conn_consumed += stream->txp_txfc_new_credit_consumed;
if (packet_full) {
txp_enlink_tmp(tmp_head, stream);
break;
}
}
txp_enlink_tmp(tmp_head, stream);
}
return 1;
}
static int txp_generate_for_el(OSSL_QUIC_TX_PACKETISER *txp,
struct txp_pkt *pkt,
int chosen_for_conn_close)
{
int rc = TXP_ERR_SUCCESS;
const uint32_t enc_level = pkt->h.enc_level;
const uint32_t pn_space = ossl_quic_enc_level_to_pn_space(enc_level);
int have_ack_eliciting = 0, done_pre_token = 0;
const struct archetype_data a = pkt->geom.adata;
/*
* Cleared if we encode any non-ACK-eliciting frame type which rules out the
* packet being a non-inflight frame. This means any non-ACK ACK-eliciting
* frame, even PADDING frames. ACK eliciting frames always cause a packet to
* become ineligible for non-inflight treatment so it is not necessary to
* clear this in cases where have_ack_eliciting is set, as it is ignored in
* that case.
*/
int can_be_non_inflight = 1;
QUIC_CFQ_ITEM *cfq_item;
QUIC_TXPIM_PKT *tpkt = NULL;
struct tx_helper *h = &pkt->h;
/* Maximum PN reached? */
if (!ossl_quic_pn_valid(txp->next_pn[pn_space]))
goto fatal_err;
if (!ossl_assert(pkt->tpkt == NULL))
goto fatal_err;
if ((pkt->tpkt = tpkt = ossl_quic_txpim_pkt_alloc(txp->args.txpim)) == NULL)
goto fatal_err;
/*
* Frame Serialization
* ===================
*
* We now serialize frames into the packet in descending order of priority.
*/
/* HANDSHAKE_DONE (Regenerate) */
if (a.allow_handshake_done && txp->want_handshake_done
&& tx_helper_get_space_left(h) >= MIN_FRAME_SIZE_HANDSHAKE_DONE) {
WPACKET *wpkt = tx_helper_begin(h);
if (wpkt == NULL)
goto fatal_err;
if (ossl_quic_wire_encode_frame_handshake_done(wpkt)) {
tpkt->had_handshake_done_frame = 1;
have_ack_eliciting = 1;
if (!tx_helper_commit(h))
goto fatal_err;
tx_helper_unrestrict(h); /* no longer need PING */
} else {
tx_helper_rollback(h);
}
}
/* MAX_DATA (Regenerate) */
if (a.allow_conn_fc
&& (txp->want_max_data
|| ossl_quic_rxfc_has_cwm_changed(txp->args.conn_rxfc, 0))
&& tx_helper_get_space_left(h) >= MIN_FRAME_SIZE_MAX_DATA) {
WPACKET *wpkt = tx_helper_begin(h);
uint64_t cwm = ossl_quic_rxfc_get_cwm(txp->args.conn_rxfc);
if (wpkt == NULL)
goto fatal_err;
if (ossl_quic_wire_encode_frame_max_data(wpkt, cwm)) {
tpkt->had_max_data_frame = 1;
have_ack_eliciting = 1;
if (!tx_helper_commit(h))
goto fatal_err;
tx_helper_unrestrict(h); /* no longer need PING */
} else {
tx_helper_rollback(h);
}
}
/* MAX_STREAMS_BIDI (Regenerate) */
if (a.allow_conn_fc
&& (txp->want_max_streams_bidi
|| ossl_quic_rxfc_has_cwm_changed(txp->args.max_streams_bidi_rxfc, 0))
&& tx_helper_get_space_left(h) >= MIN_FRAME_SIZE_MAX_STREAMS_BIDI) {
WPACKET *wpkt = tx_helper_begin(h);
uint64_t max_streams
= ossl_quic_rxfc_get_cwm(txp->args.max_streams_bidi_rxfc);
if (wpkt == NULL)
goto fatal_err;
if (ossl_quic_wire_encode_frame_max_streams(wpkt, /*is_uni=*/0,
max_streams)) {
tpkt->had_max_streams_bidi_frame = 1;
have_ack_eliciting = 1;
if (!tx_helper_commit(h))
goto fatal_err;
tx_helper_unrestrict(h); /* no longer need PING */
} else {
tx_helper_rollback(h);
}
}
/* MAX_STREAMS_UNI (Regenerate) */
if (a.allow_conn_fc
&& (txp->want_max_streams_uni
|| ossl_quic_rxfc_has_cwm_changed(txp->args.max_streams_uni_rxfc, 0))
&& tx_helper_get_space_left(h) >= MIN_FRAME_SIZE_MAX_STREAMS_UNI) {
WPACKET *wpkt = tx_helper_begin(h);
uint64_t max_streams
= ossl_quic_rxfc_get_cwm(txp->args.max_streams_uni_rxfc);
if (wpkt == NULL)
goto fatal_err;
if (ossl_quic_wire_encode_frame_max_streams(wpkt, /*is_uni=*/1,
max_streams)) {
tpkt->had_max_streams_uni_frame = 1;
have_ack_eliciting = 1;
if (!tx_helper_commit(h))
goto fatal_err;
tx_helper_unrestrict(h); /* no longer need PING */
} else {
tx_helper_rollback(h);
}
}
/* GCR Frames */
for (cfq_item = ossl_quic_cfq_get_priority_head(txp->args.cfq, pn_space);
cfq_item != NULL;
cfq_item = ossl_quic_cfq_item_get_priority_next(cfq_item, pn_space)) {
uint64_t frame_type = ossl_quic_cfq_item_get_frame_type(cfq_item);
const unsigned char *encoded = ossl_quic_cfq_item_get_encoded(cfq_item);
size_t encoded_len = ossl_quic_cfq_item_get_encoded_len(cfq_item);
switch (frame_type) {
case OSSL_QUIC_FRAME_TYPE_NEW_CONN_ID:
if (!a.allow_new_conn_id)
continue;
break;
case OSSL_QUIC_FRAME_TYPE_RETIRE_CONN_ID:
if (!a.allow_retire_conn_id)
continue;
break;
case OSSL_QUIC_FRAME_TYPE_NEW_TOKEN:
if (!a.allow_new_token)
continue;
/*
* NEW_TOKEN frames are handled via GCR, but some
* Regenerate-strategy frames should come before them (namely
* ACK, CONNECTION_CLOSE, PATH_CHALLENGE and PATH_RESPONSE). If
* we find a NEW_TOKEN frame, do these now. If there are no
* NEW_TOKEN frames in the GCR queue we will handle these below.
*/
if (!done_pre_token)
if (txp_generate_pre_token(txp, pkt,
chosen_for_conn_close,
&can_be_non_inflight))
done_pre_token = 1;
break;
case OSSL_QUIC_FRAME_TYPE_PATH_RESPONSE:
if (!a.allow_path_response)
continue;
/*
* RFC 9000 s. 8.2.2: An endpoint MUST expand datagrams that
* contain a PATH_RESPONSE frame to at least the smallest
* allowed maximum datagram size of 1200 bytes.
*/
pkt->force_pad = 1;
break;
default:
if (!a.allow_cfq_other)
continue;
break;
}
/*
* If the frame is too big, don't try to schedule any more GCR frames in
* this packet rather than sending subsequent ones out of order.
*/
if (encoded_len > tx_helper_get_space_left(h))
break;
if (!tx_helper_append_iovec(h, encoded, encoded_len))
goto fatal_err;
ossl_quic_txpim_pkt_add_cfq_item(tpkt, cfq_item);
if (ossl_quic_frame_type_is_ack_eliciting(frame_type)) {
have_ack_eliciting = 1;
tx_helper_unrestrict(h); /* no longer need PING */
}
}
/*
* If we didn't generate ACK, CONNECTION_CLOSE, PATH_CHALLENGE or
* PATH_RESPONSE (as desired) before, do so now.
*/
if (!done_pre_token)
if (txp_generate_pre_token(txp, pkt,
chosen_for_conn_close,
&can_be_non_inflight))
done_pre_token = 1;
/* CRYPTO Frames */
if (a.allow_crypto)
if (!txp_generate_crypto_frames(txp, pkt, &have_ack_eliciting))
goto fatal_err;
/* Stream-specific frames */
if (a.allow_stream_rel && txp->handshake_complete)
if (!txp_generate_stream_related(txp, pkt,
&have_ack_eliciting,
&pkt->stream_head))
goto fatal_err;
/* PING */
tx_helper_unrestrict(h);
if ((a.require_ack_eliciting
|| (txp->force_ack_eliciting & (1UL << pn_space)) != 0)
&& !have_ack_eliciting && a.allow_ping) {
WPACKET *wpkt;
wpkt = tx_helper_begin(h);
if (wpkt == NULL)
goto fatal_err;
if (!ossl_quic_wire_encode_frame_ping(wpkt)
|| !tx_helper_commit(h))
/*
* We treat a request to be ACK-eliciting as a requirement, so this
* is an error.
*/
goto fatal_err;
have_ack_eliciting = 1;
}
/* PADDING is added by ossl_quic_tx_packetiser_generate(). */
/*
* ACKM Data
* =========
*/
if (have_ack_eliciting)
can_be_non_inflight = 0;
/* ACKM Data */
tpkt->ackm_pkt.num_bytes = h->bytes_appended + pkt->geom.pkt_overhead;
tpkt->ackm_pkt.pkt_num = txp->next_pn[pn_space];
/* largest_acked is set in txp_generate_pre_token */
tpkt->ackm_pkt.pkt_space = pn_space;
tpkt->ackm_pkt.is_inflight = !can_be_non_inflight;
tpkt->ackm_pkt.is_ack_eliciting = have_ack_eliciting;
tpkt->ackm_pkt.is_pto_probe = 0;
tpkt->ackm_pkt.is_mtu_probe = 0;
tpkt->ackm_pkt.time = txp->args.now(txp->args.now_arg);
/* Done. */
return rc;
fatal_err:
/*
* Handler for fatal errors, i.e. errors causing us to abort the entire
* packet rather than just one frame. Examples of such errors include
* allocation errors.
*/
if (tpkt != NULL) {
ossl_quic_txpim_pkt_release(txp->args.txpim, tpkt);
pkt->tpkt = NULL;
}
return TXP_ERR_INTERNAL;
}
/*
* Commits and queues a packet for transmission. There is no backing out after
* this.
*
* This:
*
* - Sends the packet to the QTX for encryption and transmission;
*
* - Records the packet as having been transmitted in FIFM. ACKM is informed,
* etc. and the TXPIM record is filed.
*
* - Informs various subsystems of frames that were sent and clears frame
* wanted flags so that we do not generate the same frames again.
*
* Assumptions:
*
* - pkt is a txp_pkt for the correct EL;
*
* - pkt->tpkt is valid;
*
* - pkt->tpkt->ackm_pkt has been fully filled in;
*
* - Stream chunk records have been appended to pkt->tpkt for STREAM and
* CRYPTO frames, but not for RESET_STREAM or STOP_SENDING frames;
*
* - The chosen stream list for the packet can be fully walked from
* pkt->stream_head using stream->txp_next;
*
* - pkt->has_ack_eliciting is set correctly.
*
*/
static int txp_pkt_commit(OSSL_QUIC_TX_PACKETISER *txp,
struct txp_pkt *pkt,
uint32_t archetype,
int *txpim_pkt_reffed)
{
int rc = 1;
uint32_t enc_level = pkt->h.enc_level;
uint32_t pn_space = ossl_quic_enc_level_to_pn_space(enc_level);
QUIC_TXPIM_PKT *tpkt = pkt->tpkt;
QUIC_STREAM *stream;
OSSL_QTX_PKT txpkt;
struct archetype_data a;
*txpim_pkt_reffed = 0;
/* Cannot send a packet with an empty payload. */
if (pkt->h.bytes_appended == 0)
return 0;
if (!txp_get_archetype_data(enc_level, archetype, &a))
return 0;
/* Packet Information for QTX */
txpkt.hdr = &pkt->phdr;
txpkt.iovec = txp->el[enc_level].iovec;
txpkt.num_iovec = pkt->h.num_iovec;
txpkt.local = NULL;
txpkt.peer = BIO_ADDR_family(&txp->args.peer) == AF_UNSPEC
? NULL : &txp->args.peer;
txpkt.pn = txp->next_pn[pn_space];
txpkt.flags = OSSL_QTX_PKT_FLAG_COALESCE; /* always try to coalesce */
/* Generate TXPIM chunks representing STOP_SENDING and RESET_STREAM frames. */
for (stream = pkt->stream_head; stream != NULL; stream = stream->txp_next)
if (stream->txp_sent_stop_sending || stream->txp_sent_reset_stream) {
/* Log STOP_SENDING/RESET_STREAM chunk to TXPIM. */
QUIC_TXPIM_CHUNK chunk;
chunk.stream_id = stream->id;
chunk.start = UINT64_MAX;
chunk.end = 0;
chunk.has_fin = 0;
chunk.has_stop_sending = stream->txp_sent_stop_sending;
chunk.has_reset_stream = stream->txp_sent_reset_stream;
if (!ossl_quic_txpim_pkt_append_chunk(tpkt, &chunk))
return 0; /* alloc error */
}
/* Dispatch to FIFD. */
if (!ossl_quic_fifd_pkt_commit(&txp->fifd, tpkt))
return 0;
/*
* Transmission and Post-Packet Generation Bookkeeping
* ===================================================
*
* No backing out anymore - at this point the ACKM has recorded the packet
* as having been sent, so we need to increment our next PN counter, or
* the ACKM will complain when we try to record a duplicate packet with
* the same PN later. At this point actually sending the packet may still
* fail. In this unlikely event it will simply be handled as though it
* were a lost packet.
*/
++txp->next_pn[pn_space];
*txpim_pkt_reffed = 1;
/* Send the packet. */
if (!ossl_qtx_write_pkt(txp->args.qtx, &txpkt))
return 0;
/*
* Record FC and stream abort frames as sent; deactivate streams which no
* longer have anything to do.
*/
for (stream = pkt->stream_head; stream != NULL; stream = stream->txp_next) {
if (stream->txp_sent_fc) {
stream->want_max_stream_data = 0;
ossl_quic_rxfc_has_cwm_changed(&stream->rxfc, 1);
}
if (stream->txp_sent_stop_sending)
stream->want_stop_sending = 0;
if (stream->txp_sent_reset_stream)
stream->want_reset_stream = 0;
if (stream->txp_txfc_new_credit_consumed > 0) {
if (!ossl_assert(ossl_quic_txfc_consume_credit(&stream->txfc,
stream->txp_txfc_new_credit_consumed)))
/*
* Should not be possible, but we should continue with our
* bookkeeping as we have already committed the packet to the
* FIFD. Just change the value we return.
*/
rc = 0;
stream->txp_txfc_new_credit_consumed = 0;
}
/*
* If we no longer need to generate any flow control (MAX_STREAM_DATA),
* STOP_SENDING or RESET_STREAM frames, nor any STREAM frames (because
* the stream is drained of data or TXFC-blocked), we can mark the
* stream as inactive.
*/
ossl_quic_stream_map_update_state(txp->args.qsm, stream);
if (ossl_quic_stream_has_send_buffer(stream)
&& !ossl_quic_sstream_has_pending(stream->sstream)
&& ossl_quic_sstream_get_final_size(stream->sstream, NULL))
/*
* Transition to DATA_SENT if stream has a final size and we have
* sent all data.
*/
ossl_quic_stream_map_notify_all_data_sent(txp->args.qsm, stream);
}
/* We have now sent the packet, so update state accordingly. */
if (tpkt->ackm_pkt.is_ack_eliciting)
txp->force_ack_eliciting &= ~(1UL << pn_space);
if (tpkt->had_handshake_done_frame)
txp->want_handshake_done = 0;
if (tpkt->had_max_data_frame) {
txp->want_max_data = 0;
ossl_quic_rxfc_has_cwm_changed(txp->args.conn_rxfc, 1);
}
if (tpkt->had_max_streams_bidi_frame) {
txp->want_max_streams_bidi = 0;
ossl_quic_rxfc_has_cwm_changed(txp->args.max_streams_bidi_rxfc, 1);
}
if (tpkt->had_max_streams_uni_frame) {
txp->want_max_streams_uni = 0;
ossl_quic_rxfc_has_cwm_changed(txp->args.max_streams_uni_rxfc, 1);
}
if (tpkt->had_ack_frame)
txp->want_ack &= ~(1UL << pn_space);
if (tpkt->had_conn_close)
txp->want_conn_close = 0;
/*
* Decrement probe request counts if we have sent a packet that meets
* the requirement of a probe, namely being ACK-eliciting.
*/
if (tpkt->ackm_pkt.is_ack_eliciting) {
OSSL_ACKM_PROBE_INFO *probe_info
= ossl_ackm_get0_probe_request(txp->args.ackm);
if (enc_level == QUIC_ENC_LEVEL_INITIAL
&& probe_info->anti_deadlock_initial > 0)
--probe_info->anti_deadlock_initial;
if (enc_level == QUIC_ENC_LEVEL_HANDSHAKE
&& probe_info->anti_deadlock_handshake > 0)
--probe_info->anti_deadlock_handshake;
if (a.allow_force_ack_eliciting /* (i.e., not for 0-RTT) */
&& probe_info->pto[pn_space] > 0)
--probe_info->pto[pn_space];
}
return rc;
}
/* Ensure the iovec array is at least num elements long. */
static int txp_el_ensure_iovec(struct txp_el *el, size_t num)
{
OSSL_QTX_IOVEC *iovec;
if (el->alloc_iovec >= num)
return 1;
num = el->alloc_iovec != 0 ? el->alloc_iovec * 2 : 8;
iovec = OPENSSL_realloc(el->iovec, sizeof(OSSL_QTX_IOVEC) * num);
if (iovec == NULL)
return 0;
el->iovec = iovec;
el->alloc_iovec = num;
return 1;
}
int ossl_quic_tx_packetiser_schedule_conn_close(OSSL_QUIC_TX_PACKETISER *txp,
const OSSL_QUIC_FRAME_CONN_CLOSE *f)
{
char *reason = NULL;
size_t reason_len = f->reason_len;
size_t max_reason_len = txp_get_mdpl(txp) / 2;
if (txp->want_conn_close)
return 0;
/*
* Arbitrarily limit the length of the reason length string to half of the
* MDPL.
*/
if (reason_len > max_reason_len)
reason_len = max_reason_len;
if (reason_len > 0) {
reason = OPENSSL_memdup(f->reason, reason_len);
if (reason == NULL)
return 0;
}
txp->conn_close_frame = *f;
txp->conn_close_frame.reason = reason;
txp->conn_close_frame.reason_len = reason_len;
txp->want_conn_close = 1;
return 1;
}
void ossl_quic_tx_packetiser_set_msg_callback(OSSL_QUIC_TX_PACKETISER *txp,
ossl_msg_cb msg_callback,
SSL *msg_callback_ssl)
{
txp->msg_callback = msg_callback;
txp->msg_callback_ssl = msg_callback_ssl;
}
void ossl_quic_tx_packetiser_set_msg_callback_arg(OSSL_QUIC_TX_PACKETISER *txp,
void *msg_callback_arg)
{
txp->msg_callback_arg = msg_callback_arg;
}
QUIC_PN ossl_quic_tx_packetiser_get_next_pn(OSSL_QUIC_TX_PACKETISER *txp,
uint32_t pn_space)
{
if (pn_space >= QUIC_PN_SPACE_NUM)
return UINT64_MAX;
return txp->next_pn[pn_space];
}
OSSL_TIME ossl_quic_tx_packetiser_get_deadline(OSSL_QUIC_TX_PACKETISER *txp)
{
/*
* TXP-specific deadline computations which rely on TXP innards. This is in
* turn relied on by the QUIC_CHANNEL code to determine the channel event
* handling deadline.
*/
OSSL_TIME deadline = ossl_time_infinite();
uint32_t enc_level, pn_space;
/*
* ACK generation is not CC-gated - packets containing only ACKs are allowed
* to bypass CC. We want to generate ACK frames even if we are currently
* restricted by CC so the peer knows we have received data. The generate
* call will take care of selecting the correct packet archetype.
*/
for (enc_level = QUIC_ENC_LEVEL_INITIAL;
enc_level < QUIC_ENC_LEVEL_NUM;
++enc_level)
if (ossl_qtx_is_enc_level_provisioned(txp->args.qtx, enc_level)) {
pn_space = ossl_quic_enc_level_to_pn_space(enc_level);
deadline = ossl_time_min(deadline,
ossl_ackm_get_ack_deadline(txp->args.ackm, pn_space));
}
/* When will CC let us send more? */
if (txp->args.cc_method->get_tx_allowance(txp->args.cc_data) == 0)
deadline = ossl_time_min(deadline,
txp->args.cc_method->get_wakeup_deadline(txp->args.cc_data));
return deadline;
}
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