RepoMirrors
/
haproxy
mirror of http://git.haproxy.org/git/haproxy.git/
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity
haproxy/src/quic_tx.c

2349 lines
73 KiB
C
Raw Blame History

/*
* QUIC protocol implementation. Lower layer with internal features implemented
* here such as QUIC encryption, idle timeout, acknowledgement and
* retransmission.
*
* Copyright 2020 HAProxy Technologies, Frederic Lecaille <flecaille@haproxy.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
*/
#include <haproxy/quic_tx.h>
#include <haproxy/pool.h>
#include <haproxy/trace.h>
#include <haproxy/quic_cid.h>
#include <haproxy/quic_conn.h>
#include <haproxy/quic_retransmit.h>
#include <haproxy/quic_retry.h>
#include <haproxy/quic_sock.h>
#include <haproxy/quic_tls.h>
#include <haproxy/quic_trace.h>
#include <haproxy/ssl_sock-t.h>
DECLARE_POOL(pool_head_quic_tx_packet, "quic_tx_packet", sizeof(struct quic_tx_packet));
DECLARE_POOL(pool_head_quic_cc_buf, "quic_cc_buf", QUIC_MAX_CC_BUFSIZE);
static struct quic_tx_packet *qc_build_pkt(unsigned char **pos, const unsigned char *buf_end,
struct quic_enc_level *qel, struct quic_tls_ctx *ctx,
struct list *frms, struct quic_conn *qc,
const struct quic_version *ver, size_t dglen, int pkt_type,
int must_ack, int padding, int probe, int cc, int *err);
static void quic_packet_encrypt(unsigned char *payload, size_t payload_len,
unsigned char *aad, size_t aad_len, uint64_t pn,
struct quic_tls_ctx *tls_ctx, struct quic_conn *qc,
int *fail)
{
unsigned char iv[QUIC_TLS_IV_LEN];
unsigned char *tx_iv = tls_ctx->tx.iv;
size_t tx_iv_sz = tls_ctx->tx.ivlen;
struct enc_debug_info edi;
TRACE_ENTER(QUIC_EV_CONN_ENCPKT, qc);
*fail = 0;
quic_aead_iv_build(iv, sizeof iv, tx_iv, tx_iv_sz, pn);
if (!quic_tls_encrypt(payload, payload_len, aad, aad_len,
tls_ctx->tx.ctx, tls_ctx->tx.aead, iv)) {
TRACE_ERROR("QUIC packet encryption failed", QUIC_EV_CONN_ENCPKT, qc);
*fail = 1;
enc_debug_info_init(&edi, payload, payload_len, aad, aad_len, pn);
}
TRACE_LEAVE(QUIC_EV_CONN_ENCPKT, qc);
}
/* Free <pkt> TX packet and its attached frames.
* This is the responsibility of the caller to remove this packet of
* any data structure it was possibly attached to.
*/
static inline void free_quic_tx_packet(struct quic_conn *qc,
struct quic_tx_packet *pkt)
{
struct quic_frame *frm, *frmbak;
TRACE_ENTER(QUIC_EV_CONN_TXPKT, qc);
if (!pkt)
goto leave;
list_for_each_entry_safe(frm, frmbak, &pkt->frms, list)
qc_frm_free(qc, &frm);
pool_free(pool_head_quic_tx_packet, pkt);
leave:
TRACE_LEAVE(QUIC_EV_CONN_TXPKT, qc);
}
/* Allocate Tx buffer from <qc> quic-conn if needed.
*
* Returns allocated buffer or NULL on error.
*/
struct buffer *qc_txb_alloc(struct quic_conn *qc)
{
struct buffer *buf = &qc->tx.buf;
if (!b_alloc(buf))
return NULL;
return buf;
}
/* Free Tx buffer from <qc> if it is empty. */
void qc_txb_release(struct quic_conn *qc)
{
struct buffer *buf = &qc->tx.buf;
/* For the moment sending function is responsible to purge the buffer
* entirely. It may change in the future but this requires to be able
* to reuse old data.
* For the moment we do not care to leave data in the buffer for
* a connection which is supposed to be killed asap.
*/
BUG_ON_HOT(buf && b_data(buf));
if (!b_data(buf)) {
b_free(buf);
offer_buffers(NULL, 1);
}
}
/* Return the TX buffer dedicated to the "connection close" datagram to be built
* if an immediate close is required after having allocated it or directly
* allocate a TX buffer if an immediate close is not required.
*/
struct buffer *qc_get_txb(struct quic_conn *qc)
{
struct buffer *buf;
if (qc->flags & QUIC_FL_CONN_IMMEDIATE_CLOSE) {
TRACE_PROTO("Immediate close required", QUIC_EV_CONN_PHPKTS, qc);
buf = &qc->tx.cc_buf;
if (b_is_null(buf)) {
qc->tx.cc_buf_area = pool_alloc(pool_head_quic_cc_buf);
if (!qc->tx.cc_buf_area)
goto err;
}
/* In every case, initialize ->tx.cc_buf */
qc->tx.cc_buf = b_make(qc->tx.cc_buf_area, QUIC_MAX_CC_BUFSIZE, 0, 0);
}
else {
buf = qc_txb_alloc(qc);
if (!buf)
goto err;
}
return buf;
err:
return NULL;
}
/* Commit a datagram payload written into <buf> of length <length>. <first_pkt>
* must contains the address of the first packet stored in the payload.
*
* Caller is responsible that there is enough space in the buffer.
*/
static void qc_txb_store(struct buffer *buf, uint16_t length,
struct quic_tx_packet *first_pkt)
{
const size_t hdlen = sizeof(uint16_t) + sizeof(void *);
BUG_ON_HOT(b_contig_space(buf) < hdlen); /* this must not happen */
write_u16(b_tail(buf), length);
write_ptr(b_tail(buf) + sizeof(length), first_pkt);
b_add(buf, hdlen + length);
}
/* Returns 1 if a packet may be built for <qc> from <qel> encryption level
* with <frms> as ack-eliciting frame list to send, 0 if not.
* <cc> must equal to 1 if an immediate close was asked, 0 if not.
* <probe> must equalt to 1 if a probing packet is required, 0 if not.
* Also set <*must_ack> to inform the caller if an acknowledgement should be sent.
*/
static int qc_may_build_pkt(struct quic_conn *qc, struct list *frms,
struct quic_enc_level *qel, int cc, int probe,
int *must_ack)
{
int force_ack = qel == qc->iel || qel == qc->hel;
int nb_aepkts_since_last_ack = qel->pktns->rx.nb_aepkts_since_last_ack;
/* An acknowledgement must be sent if this has been forced by the caller,
* typically during the handshake when the packets must be acknowledged as
* soon as possible. This is also the case when the ack delay timer has been
* triggered, or at least every QUIC_MAX_RX_AEPKTS_SINCE_LAST_ACK packets.
*/
*must_ack = (qc->flags & QUIC_FL_CONN_ACK_TIMER_FIRED) ||
((qel->pktns->flags & QUIC_FL_PKTNS_ACK_REQUIRED) &&
(force_ack || nb_aepkts_since_last_ack >= QUIC_MAX_RX_AEPKTS_SINCE_LAST_ACK));
TRACE_PRINTF(TRACE_LEVEL_DEVELOPER, QUIC_EV_CONN_PHPKTS, qc, 0, 0, 0,
"has_sec=%d cc=%d probe=%d must_ack=%d frms=%d prep_in_fligh=%llu cwnd=%llu",
quic_tls_has_tx_sec(qel), cc, probe, *must_ack, LIST_ISEMPTY(frms),
(ullong)qc->path->prep_in_flight, (ullong)qc->path->cwnd);
/* Do not build any more packet if the TX secrets are not available or
* if there is nothing to send, i.e. if no CONNECTION_CLOSE or ACK are required
* and if there is no more packets to send upon PTO expiration
* and if there is no more ack-eliciting frames to send or in flight
* congestion control limit is reached for prepared data
*/
if (!quic_tls_has_tx_sec(qel) ||
(!cc && !probe && !*must_ack &&
(LIST_ISEMPTY(frms) || qc->path->prep_in_flight >= qc->path->cwnd))) {
return 0;
}
return 1;
}
/* Prepare as much as possible QUIC packets for sending from prebuilt frames
* <frms>. Each packet is stored in a distinct datagram written to <buf>.
*
* Each datagram is prepended by a two fields header : the datagram length and
* the address of the packet contained in the datagram.
*
* Returns the number of bytes prepared in packets if succeeded (may be 0), or
* -1 if something wrong happened.
*/
static int qc_prep_app_pkts(struct quic_conn *qc, struct buffer *buf,
struct list *frms)
{
int ret = -1, cc;
struct quic_enc_level *qel;
unsigned char *end, *pos;
struct quic_tx_packet *pkt;
size_t total;
TRACE_ENTER(QUIC_EV_CONN_PHPKTS, qc);
qel = qc->ael;
total = 0;
pos = (unsigned char *)b_tail(buf);
cc = qc->flags & QUIC_FL_CONN_IMMEDIATE_CLOSE;
/* Each datagram is prepended with its length followed by the address
* of the first packet in the datagram (QUIC_DGRAM_HEADLEN).
*/
while ((!cc && b_contig_space(buf) >= (int)qc->path->mtu + QUIC_DGRAM_HEADLEN) ||
(cc && b_contig_space(buf) >= QUIC_MIN_CC_PKTSIZE + QUIC_DGRAM_HEADLEN)) {
int err, probe, must_ack;
TRACE_PROTO("TX prep app pkts", QUIC_EV_CONN_PHPKTS, qc, qel, frms);
probe = 0;
/* We do not probe if an immediate close was asked */
if (!cc)
probe = qel->pktns->tx.pto_probe;
if (!qc_may_build_pkt(qc, frms, qel, cc, probe, &must_ack))
break;
/* Leave room for the datagram header */
pos += QUIC_DGRAM_HEADLEN;
if (cc) {
end = pos + QUIC_MIN_CC_PKTSIZE;
}
else if (!quic_peer_validated_addr(qc) && qc_is_listener(qc)) {
end = pos + QUIC_MIN(qc->path->mtu, quic_may_send_bytes(qc));
}
else {
end = pos + qc->path->mtu;
}
pkt = qc_build_pkt(&pos, end, qel, &qel->tls_ctx, frms, qc, NULL, 0,
QUIC_PACKET_TYPE_SHORT, must_ack, 0, probe, cc, &err);
switch (err) {
case -3:
qc_purge_txbuf(qc, buf);
goto leave;
case -2:
// trace already emitted by function above
goto leave;
case -1:
/* As we provide qc_build_pkt() with an enough big buffer to fulfill an
* MTU, we are here because of the congestion control window. There is
* no need to try to reuse this buffer.
*/
TRACE_PROTO("could not prepare anymore packet", QUIC_EV_CONN_PHPKTS, qc, qel);
goto out;
default:
break;
}
/* This is to please to GCC. We cannot have (err >= 0 && !pkt) */
BUG_ON(!pkt);
if (qc->flags & QUIC_FL_CONN_RETRANS_OLD_DATA)
pkt->flags |= QUIC_FL_TX_PACKET_PROBE_WITH_OLD_DATA;
total += pkt->len;
/* Write datagram header. */
qc_txb_store(buf, pkt->len, pkt);
/* Build only one datagram when an immediate close is required. */
if (cc)
break;
}
out:
if (total && cc) {
BUG_ON(buf != &qc->tx.cc_buf);
qc->tx.cc_dgram_len = total;
}
ret = total;
leave:
TRACE_LEAVE(QUIC_EV_CONN_PHPKTS, qc);
return ret;
}
/* Free all frames in <l> list. In addition also remove all these frames
* from the original ones if they are the results of duplications.
*/
static inline void qc_free_frm_list(struct quic_conn *qc, struct list *l)
{
struct quic_frame *frm, *frmbak;
TRACE_ENTER(QUIC_EV_CONN_TXPKT, qc);
list_for_each_entry_safe(frm, frmbak, l, list) {
LIST_DEL_INIT(&frm->ref);
qc_frm_free(qc, &frm);
}
TRACE_LEAVE(QUIC_EV_CONN_TXPKT, qc);
}
/* Free <pkt> TX packet and all the packets coalesced to it. */
static inline void qc_free_tx_coalesced_pkts(struct quic_conn *qc,
struct quic_tx_packet *p)
{
struct quic_tx_packet *pkt, *nxt_pkt;
TRACE_ENTER(QUIC_EV_CONN_TXPKT, qc);
for (pkt = p; pkt; pkt = nxt_pkt) {
qc_free_frm_list(qc, &pkt->frms);
nxt_pkt = pkt->next;
pool_free(pool_head_quic_tx_packet, pkt);
}
TRACE_LEAVE(QUIC_EV_CONN_TXPKT, qc);
}
/* Purge <buf> TX buffer from its prepare packets. */
static void qc_purge_tx_buf(struct quic_conn *qc, struct buffer *buf)
{
while (b_contig_data(buf, 0)) {
uint16_t dglen;
struct quic_tx_packet *pkt;
size_t headlen = sizeof dglen + sizeof pkt;
dglen = read_u16(b_head(buf));
pkt = read_ptr(b_head(buf) + sizeof dglen);
qc_free_tx_coalesced_pkts(qc, pkt);
b_del(buf, dglen + headlen);
}
BUG_ON(b_data(buf));
}
/* Send datagrams stored in <buf>.
*
* This function returns 1 for success. On error, there is several behavior
* depending on underlying sendto() error :
* - for an unrecoverable error, 0 is returned and connection is killed.
* - a transient error is handled differently if connection has its owned
* socket. If this is the case, 0 is returned and socket is subscribed on the
* poller. The other case is assimilated to a success case with 1 returned.
* Remaining data are purged from the buffer and will eventually be detected
* as lost which gives the opportunity to retry sending.
*/
int qc_send_ppkts(struct buffer *buf, struct ssl_sock_ctx *ctx)
{
int ret = 0;
struct quic_conn *qc;
char skip_sendto = 0;
qc = ctx->qc;
TRACE_ENTER(QUIC_EV_CONN_SPPKTS, qc);
while (b_contig_data(buf, 0)) {
unsigned char *pos;
struct buffer tmpbuf = { };
struct quic_tx_packet *first_pkt, *pkt, *next_pkt;
uint16_t dglen;
size_t headlen = sizeof dglen + sizeof first_pkt;
unsigned int time_sent;
pos = (unsigned char *)b_head(buf);
dglen = read_u16(pos);
BUG_ON_HOT(!dglen); /* this should not happen */
pos += sizeof dglen;
first_pkt = read_ptr(pos);
pos += sizeof first_pkt;
tmpbuf.area = (char *)pos;
tmpbuf.size = tmpbuf.data = dglen;
TRACE_PROTO("TX dgram", QUIC_EV_CONN_SPPKTS, qc);
/* If sendto is on error just skip the call to it for the rest
* of the loop but continue to purge the buffer. Data will be
* transmitted when QUIC packets are detected as lost on our
* side.
*
* TODO use fd-monitoring to detect when send operation can be
* retry. This should improve the bandwidth without relying on
* retransmission timer. However, it requires a major rework on
* quic-conn fd management.
*/
if (!skip_sendto) {
int ret = qc_snd_buf(qc, &tmpbuf, tmpbuf.data, 0);
if (ret < 0) {
TRACE_ERROR("sendto fatal error", QUIC_EV_CONN_SPPKTS, qc, first_pkt);
qc_kill_conn(qc);
qc_free_tx_coalesced_pkts(qc, first_pkt);
b_del(buf, dglen + headlen);
qc_purge_tx_buf(qc, buf);
goto leave;
}
else if (!ret) {
/* Connection owned socket : poller will wake us up when transient error is cleared. */
if (qc_test_fd(qc)) {
TRACE_ERROR("sendto error, subscribe to poller", QUIC_EV_CONN_SPPKTS, qc);
goto leave;
}
/* No connection owned-socket : rely on retransmission to retry sending. */
skip_sendto = 1;
TRACE_ERROR("sendto error, simulate sending for the rest of data", QUIC_EV_CONN_SPPKTS, qc);
}
}
b_del(buf, dglen + headlen);
qc->bytes.tx += tmpbuf.data;
time_sent = now_ms;
for (pkt = first_pkt; pkt; pkt = next_pkt) {
/* RFC 9000 14.1 Initial datagram size
* a server MUST expand the payload of all UDP datagrams carrying ack-eliciting
* Initial packets to at least the smallest allowed maximum datagram size of
* 1200 bytes.
*/
qc->cntrs.sent_pkt++;
BUG_ON_HOT(pkt->type == QUIC_PACKET_TYPE_INITIAL &&
(pkt->flags & QUIC_FL_TX_PACKET_ACK_ELICITING) &&
dglen < QUIC_INITIAL_PACKET_MINLEN);
pkt->time_sent = time_sent;
if (pkt->flags & QUIC_FL_TX_PACKET_ACK_ELICITING) {
pkt->pktns->tx.time_of_last_eliciting = time_sent;
qc->path->ifae_pkts++;
if (qc->flags & QUIC_FL_CONN_IDLE_TIMER_RESTARTED_AFTER_READ)
qc_idle_timer_rearm(qc, 0, 0);
}
if (!(qc->flags & QUIC_FL_CONN_CLOSING) &&
(pkt->flags & QUIC_FL_TX_PACKET_CC)) {
qc->flags |= QUIC_FL_CONN_CLOSING;
qc_detach_th_ctx_list(qc, 1);
/* RFC 9000 10.2. Immediate Close:
* The closing and draining connection states exist to ensure
* that connections close cleanly and that delayed or reordered
* packets are properly discarded. These states SHOULD persist
* for at least three times the current PTO interval...
*
* Rearm the idle timeout only one time when entering closing
* state.
*/
qc_idle_timer_do_rearm(qc, 0);
if (qc->timer_task) {
task_destroy(qc->timer_task);
qc->timer_task = NULL;
}
}
qc->path->in_flight += pkt->in_flight_len;
pkt->pktns->tx.in_flight += pkt->in_flight_len;
if (pkt->in_flight_len)
qc_set_timer(qc);
TRACE_PROTO("TX pkt", QUIC_EV_CONN_SPPKTS, qc, pkt);
next_pkt = pkt->next;
quic_tx_packet_refinc(pkt);
eb64_insert(&pkt->pktns->tx.pkts, &pkt->pn_node);
}
}
ret = 1;
leave:
TRACE_LEAVE(QUIC_EV_CONN_SPPKTS, qc);
return ret;
}
/* Flush txbuf for <qc> connection. This must be called prior to a packet
* preparation when txbuf contains older data. A send will be conducted for
* these data.
*
* Returns 1 on success : buffer is empty and can be use for packet
* preparation. On error 0 is returned.
*/
int qc_purge_txbuf(struct quic_conn *qc, struct buffer *buf)
{
TRACE_ENTER(QUIC_EV_CONN_TXPKT, qc);
/* This operation can only be conducted if txbuf is not empty. This
* case only happens for connection with their owned socket due to an
* older transient sendto() error.
*/
BUG_ON(!qc_test_fd(qc));
if (b_data(buf) && !qc_send_ppkts(buf, qc->xprt_ctx)) {
if (qc->flags & QUIC_FL_CONN_TO_KILL)
qc_txb_release(qc);
TRACE_DEVEL("leaving in error", QUIC_EV_CONN_TXPKT, qc);
return 0;
}
TRACE_LEAVE(QUIC_EV_CONN_TXPKT, qc);
return 1;
}
/* Try to send application frames from list <frms> on connection <qc>.
*
* Use qc_send_app_probing wrapper when probing with old data.
*
* Returns 1 on success. Some data might not have been sent due to congestion,
* in this case they are left in <frms> input list. The caller may subscribe on
* quic-conn to retry later.
*
* Returns 0 on critical error.
* TODO review and classify more distinctly transient from definitive errors to
* allow callers to properly handle it.
*/
int qc_send_app_pkts(struct quic_conn *qc, struct list *frms)
{
int status = 0, ret;
struct buffer *buf;
TRACE_ENTER(QUIC_EV_CONN_TXPKT, qc);
buf = qc_get_txb(qc);
if (!buf) {
TRACE_ERROR("could not get a buffer", QUIC_EV_CONN_TXPKT, qc);
goto err;
}
if (b_data(buf) && !qc_purge_txbuf(qc, buf))
goto err;
/* Prepare and send packets until we could not further prepare packets. */
do {
/* Currently buf cannot be non-empty at this stage. Even if a
* previous sendto() has failed it is emptied to simulate
* packet emission and rely on QUIC lost detection to try to
* emit it.
*/
BUG_ON_HOT(b_data(buf));
b_reset(buf);
ret = qc_prep_app_pkts(qc, buf, frms);
if (b_data(buf) && !qc_send_ppkts(buf, qc->xprt_ctx)) {
if (qc->flags & QUIC_FL_CONN_TO_KILL)
qc_txb_release(qc);
goto err;
}
} while (ret > 0);
qc_txb_release(qc);
if (ret < 0)
goto err;
status = 1;
TRACE_LEAVE(QUIC_EV_CONN_TXPKT, qc);
return status;
err:
TRACE_DEVEL("leaving in error", QUIC_EV_CONN_TXPKT, qc);
return 0;
}
/* Try to send application frames from list <frms> on connection <qc>. Use this
* function when probing is required.
*
* Returns the result from qc_send_app_pkts function.
*/
static forceinline int qc_send_app_probing(struct quic_conn *qc,
struct list *frms)
{
int ret;
TRACE_ENTER(QUIC_EV_CONN_TXPKT, qc);
TRACE_PROTO("preparing old data (probing)", QUIC_EV_CONN_FRMLIST, qc, frms);
qc->flags |= QUIC_FL_CONN_RETRANS_OLD_DATA;
ret = qc_send_app_pkts(qc, frms);
qc->flags &= ~QUIC_FL_CONN_RETRANS_OLD_DATA;
TRACE_LEAVE(QUIC_EV_CONN_TXPKT, qc);
return ret;
}
/* Try to send application frames from list <frms> on connection <qc>. This
* function is provided for MUX upper layer usage only.
*
* Returns the result from qc_send_app_pkts function.
*/
int qc_send_mux(struct quic_conn *qc, struct list *frms)
{
int ret;
TRACE_ENTER(QUIC_EV_CONN_TXPKT, qc);
BUG_ON(qc->mux_state != QC_MUX_READY); /* Only MUX can uses this function so it must be ready. */
if (qc->conn->flags & CO_FL_SOCK_WR_SH) {
qc->conn->flags |= CO_FL_ERROR | CO_FL_SOCK_RD_SH;
TRACE_DEVEL("connection on error", QUIC_EV_CONN_TXPKT, qc);
return 0;
}
/* Try to send post handshake frames first unless on 0-RTT. */
if ((qc->flags & QUIC_FL_CONN_NEED_POST_HANDSHAKE_FRMS) &&
qc->state >= QUIC_HS_ST_COMPLETE) {
quic_build_post_handshake_frames(qc);
qc_send_app_pkts(qc, &qc->ael->pktns->tx.frms);
}
TRACE_STATE("preparing data (from MUX)", QUIC_EV_CONN_TXPKT, qc);
qc->flags |= QUIC_FL_CONN_TX_MUX_CONTEXT;
ret = qc_send_app_pkts(qc, frms);
qc->flags &= ~QUIC_FL_CONN_TX_MUX_CONTEXT;
TRACE_LEAVE(QUIC_EV_CONN_TXPKT, qc);
return ret;
}
/* Return the encryption level following the one which contains <el> list head
* depending on <retrans> TX mode (retranmission or not).
*/
static inline struct quic_enc_level *qc_list_next_qel(struct list *el, int retrans)
{
return !retrans ? LIST_NEXT(el, struct quic_enc_level *, list) :
LIST_NEXT(el, struct quic_enc_level *, retrans);
}
/* Return the encryption level following <qel> depending on <retrans> TX mode
* (retranmission or not).
*/
static inline struct quic_enc_level *qc_next_qel(struct quic_enc_level *qel, int retrans)
{
struct list *el = !retrans ? &qel->list : &qel->retrans;
return qc_list_next_qel(el, retrans);
}
/* Return 1 if <qel> is at the head of its list, 0 if not. */
static inline int qc_qel_is_head(struct quic_enc_level *qel, struct list *l,
int retrans)
{
return !retrans ? &qel->list == l : &qel->retrans == l;
}
/* Select <*tls_ctx>, <*frms> and <*ver> for the encryption level <qel> of <qc> QUIC
* connection, depending on its state, especially the negotiated version and if
* retransmissions are required. If this the case <qels> is the list of encryption
* levels to used, or NULL if no retransmissions are required.
* Never fails.
*/
static inline void qc_select_tls_frms_ver(struct quic_conn *qc,
struct quic_enc_level *qel,
struct quic_tls_ctx **tls_ctx,
struct list **frms,
const struct quic_version **ver,
struct list *qels)
{
if (qc->negotiated_version) {
*ver = qc->negotiated_version;
if (qel == qc->iel)
*tls_ctx = qc->nictx;
else
*tls_ctx = &qel->tls_ctx;
}
else {
*ver = qc->original_version;
*tls_ctx = &qel->tls_ctx;
}
if (!qels)
*frms = &qel->pktns->tx.frms;
else
*frms = qel->retrans_frms;
}
/* Prepare as much as possible QUIC datagrams/packets for sending from <qels>
* list of encryption levels. Several packets can be coalesced into a single
* datagram. The result is written into <buf>. Note that if <qels> is NULL,
* the encryption levels which will be used are those currently allocated
* and attached to the connection.
*
* Each datagram is prepended by a two fields header : the datagram length and
* the address of first packet in the datagram.
*
* Returns the number of bytes prepared in datragrams/packets if succeeded
* (may be 0), or -1 if something wrong happened.
*/
int qc_prep_hpkts(struct quic_conn *qc, struct buffer *buf, struct list *qels)
{
int ret, cc, retrans, padding;
struct quic_tx_packet *first_pkt, *prv_pkt;
unsigned char *end, *pos;
uint16_t dglen;
size_t total;
struct list *qel_list;
struct quic_enc_level *qel;
TRACE_ENTER(QUIC_EV_CONN_IO_CB, qc);
/* Currently qc_prep_pkts() does not handle buffer wrapping so the
* caller must ensure that buf is reset.
*/
BUG_ON_HOT(buf->head || buf->data);
ret = -1;
cc = qc->flags & QUIC_FL_CONN_IMMEDIATE_CLOSE;
retrans = !!qels;
padding = 0;
first_pkt = prv_pkt = NULL;
end = pos = (unsigned char *)b_head(buf);
dglen = 0;
total = 0;
qel_list = qels ? qels : &qc->qel_list;
qel = qc_list_next_qel(qel_list, retrans);
while (!qc_qel_is_head(qel, qel_list, retrans)) {
struct quic_tls_ctx *tls_ctx;
const struct quic_version *ver;
struct list *frms, *next_frms;
struct quic_enc_level *next_qel;
if (qel == qc->eel) {
/* Next encryption level */
qel = qc_next_qel(qel, retrans);
continue;
}
qc_select_tls_frms_ver(qc, qel, &tls_ctx, &frms, &ver, qels);
next_qel = qc_next_qel(qel, retrans);
next_frms = qc_qel_is_head(next_qel, qel_list, retrans) ? NULL :
!qels ? &next_qel->pktns->tx.frms : next_qel->retrans_frms;
/* Build as much as datagrams at <qel> encryption level.
* Each datagram is prepended with its length followed by the address
* of the first packet in the datagram (QUIC_DGRAM_HEADLEN).
*/
while ((!cc && b_contig_space(buf) >= (int)qc->path->mtu + QUIC_DGRAM_HEADLEN) ||
(cc && b_contig_space(buf) >= QUIC_MIN_CC_PKTSIZE + QUIC_DGRAM_HEADLEN) || prv_pkt) {
int err, probe, must_ack;
enum quic_pkt_type pkt_type;
struct quic_tx_packet *cur_pkt;
TRACE_PROTO("TX prep pkts", QUIC_EV_CONN_PHPKTS, qc, qel);
probe = 0;
/* We do not probe if an immediate close was asked */
if (!cc)
probe = qel->pktns->tx.pto_probe;
if (!qc_may_build_pkt(qc, frms, qel, cc, probe, &must_ack)) {
if (prv_pkt && qc_qel_is_head(next_qel, qel_list, retrans)) {
qc_txb_store(buf, dglen, first_pkt);
/* Build only one datagram when an immediate close is required. */
if (cc)
goto out;
}
TRACE_DEVEL("next encryption level", QUIC_EV_CONN_PHPKTS, qc);
break;
}
if (!prv_pkt) {
/* Leave room for the datagram header */
pos += QUIC_DGRAM_HEADLEN;
if (cc) {
end = pos + QUIC_MIN_CC_PKTSIZE;
}
else if (!quic_peer_validated_addr(qc) && qc_is_listener(qc)) {
end = pos + QUIC_MIN(qc->path->mtu, quic_may_send_bytes(qc));
}
else {
end = pos + qc->path->mtu;
}
}
/* RFC 9000 14.1 Initial datagram size
* a server MUST expand the payload of all UDP datagrams carrying ack-eliciting
* Initial packets to at least the smallest allowed maximum datagram size of
* 1200 bytes.
*
* Ensure that no ack-eliciting packets are sent into too small datagrams
*/
if (qel == qc->iel && !LIST_ISEMPTY(frms)) {
if (end - pos < QUIC_INITIAL_PACKET_MINLEN) {
TRACE_PROTO("No more enough room to build an Initial packet",
QUIC_EV_CONN_PHPKTS, qc);
break;
}
/* Pad this Initial packet if there is no ack-eliciting frames to send from
* the next packet number space.
*/
if (!next_frms || LIST_ISEMPTY(next_frms))
padding = 1;
}
pkt_type = quic_enc_level_pkt_type(qc, qel);
cur_pkt = qc_build_pkt(&pos, end, qel, tls_ctx, frms,
qc, ver, dglen, pkt_type,
must_ack, padding, probe, cc, &err);
switch (err) {
case -3:
if (first_pkt)
qc_txb_store(buf, dglen, first_pkt);
qc_purge_tx_buf(qc, buf);
goto leave;
case -2:
// trace already emitted by function above
goto leave;
case -1:
/* If there was already a correct packet present, set the
* current datagram as prepared into <cbuf>.
*/
if (prv_pkt)
qc_txb_store(buf, dglen, first_pkt);
TRACE_PROTO("could not prepare anymore packet", QUIC_EV_CONN_PHPKTS, qc, qel);
goto out;
default:
break;
}
/* This is to please to GCC. We cannot have (err >= 0 && !cur_pkt) */
BUG_ON(!cur_pkt);
total += cur_pkt->len;
dglen += cur_pkt->len;
if (qc->flags & QUIC_FL_CONN_RETRANS_OLD_DATA)
cur_pkt->flags |= QUIC_FL_TX_PACKET_PROBE_WITH_OLD_DATA;
/* keep trace of the first packet in the datagram */
if (!first_pkt)
first_pkt = cur_pkt;
/* Attach the current one to the previous one and vice versa */
if (prv_pkt) {
prv_pkt->next = cur_pkt;
cur_pkt->prev = prv_pkt;
cur_pkt->flags |= QUIC_FL_TX_PACKET_COALESCED;
}
/* If there is no more packet to build for this encryption level,
* select the next one <next_qel>, if any, to coalesce a packet in
* the same datagram, except if <qel> is the Application data
* encryption level which cannot be selected to do that.
*/
if (LIST_ISEMPTY(frms) && qel != qc->ael &&
!qc_qel_is_head(next_qel, qel_list, retrans)) {
if (qel == qc->iel &&
(!qc_is_listener(qc) ||
cur_pkt->flags & QUIC_FL_TX_PACKET_ACK_ELICITING))
padding = 1;
prv_pkt = cur_pkt;
break;
}
else {
qc_txb_store(buf, dglen, first_pkt);
/* Build only one datagram when an immediate close is required. */
if (cc)
goto out;
first_pkt = NULL;
dglen = 0;
padding = 0;
prv_pkt = NULL;
}
}
/* Next encryption level */
qel = next_qel;
}
out:
if (cc && total) {
BUG_ON(buf != &qc->tx.cc_buf);
BUG_ON(dglen != total);
qc->tx.cc_dgram_len = dglen;
}
ret = total;
leave:
TRACE_LEAVE(QUIC_EV_CONN_PHPKTS, qc);
return ret;
}
/* Sends handshake packets from up to two encryption levels <tel> and <next_te>
* with <tel_frms> and <next_tel_frms> as frame list respectively for <qc>
* QUIC connection. <old_data> is used as boolean to send data already sent but
* not already acknowledged (in flight).
* Returns 1 if succeeded, 0 if not.
*/
int qc_send_hdshk_pkts(struct quic_conn *qc, int old_data,
struct quic_enc_level *qel1, struct quic_enc_level *qel2)
{
int ret, status = 0;
struct buffer *buf = qc_get_txb(qc);
struct list qels = LIST_HEAD_INIT(qels);
TRACE_ENTER(QUIC_EV_CONN_TXPKT, qc);
if (!buf) {
TRACE_ERROR("buffer allocation failed", QUIC_EV_CONN_TXPKT, qc);
goto leave;
}
if (b_data(buf) && !qc_purge_txbuf(qc, buf)) {
TRACE_ERROR("Could not purge TX buffer", QUIC_EV_CONN_TXPKT, qc);
goto out;
}
/* Currently buf cannot be non-empty at this stage. Even if a previous
* sendto() has failed it is emptied to simulate packet emission and
* rely on QUIC lost detection to try to emit it.
*/
BUG_ON_HOT(b_data(buf));
b_reset(buf);
if (old_data) {
TRACE_STATE("old data for probing asked", QUIC_EV_CONN_TXPKT, qc);
qc->flags |= QUIC_FL_CONN_RETRANS_OLD_DATA;
}
if (qel1) {
BUG_ON(LIST_INLIST(&qel1->retrans));
LIST_APPEND(&qels, &qel1->retrans);
}
if (qel2) {
BUG_ON(LIST_INLIST(&qel2->retrans));
LIST_APPEND(&qels, &qel2->retrans);
}
ret = qc_prep_hpkts(qc, buf, &qels);
if (ret == -1) {
qc_txb_release(qc);
TRACE_ERROR("Could not build some packets", QUIC_EV_CONN_TXPKT, qc);
goto out;
}
if (ret && !qc_send_ppkts(buf, qc->xprt_ctx)) {
if (qc->flags & QUIC_FL_CONN_TO_KILL)
qc_txb_release(qc);
TRACE_ERROR("Could not send some packets", QUIC_EV_CONN_TXPKT, qc);
goto out;
}
qc_txb_release(qc);
status = 1;
out:
if (qel1) {
LIST_DEL_INIT(&qel1->retrans);
qel1->retrans_frms = NULL;
}
if (qel2) {
LIST_DEL_INIT(&qel2->retrans);
qel2->retrans_frms = NULL;
}
TRACE_STATE("no more need old data for probing", QUIC_EV_CONN_TXPKT, qc);
qc->flags &= ~QUIC_FL_CONN_RETRANS_OLD_DATA;
leave:
TRACE_LEAVE(QUIC_EV_CONN_TXPKT, qc);
return status;
}
/* Retransmit up to two datagrams depending on packet number space.
* Return 0 when failed, 0 if not.
*/
int qc_dgrams_retransmit(struct quic_conn *qc)
{
int ret = 0;
int sret;
struct quic_pktns *ipktns = qc->ipktns;
struct quic_pktns *hpktns = qc->hpktns;
struct quic_pktns *apktns = qc->apktns;
TRACE_ENTER(QUIC_EV_CONN_TXPKT, qc);
/* Note that if the Initial packet number space is not discarded,
* this is also the case for the Handshake packet number space.
*/
if (ipktns && (ipktns->flags & QUIC_FL_PKTNS_PROBE_NEEDED)) {
int i;
for (i = 0; i < QUIC_MAX_NB_PTO_DGRAMS; i++) {
struct list ifrms = LIST_HEAD_INIT(ifrms);
struct list hfrms = LIST_HEAD_INIT(hfrms);
struct list qels = LIST_HEAD_INIT(qels);
qc_prep_hdshk_fast_retrans(qc, &ifrms, &hfrms);
TRACE_DEVEL("Avail. ack eliciting frames", QUIC_EV_CONN_FRMLIST, qc, &ifrms);
TRACE_DEVEL("Avail. ack eliciting frames", QUIC_EV_CONN_FRMLIST, qc, &hfrms);
if (!LIST_ISEMPTY(&ifrms)) {
ipktns->tx.pto_probe = 1;
if (!LIST_ISEMPTY(&hfrms))
hpktns->tx.pto_probe = 1;
qc->iel->retrans_frms = &ifrms;
if (qc->hel)
qc->hel->retrans_frms = &hfrms;
sret = qc_send_hdshk_pkts(qc, 1, qc->iel, qc->hel);
qc_free_frm_list(qc, &ifrms);
qc_free_frm_list(qc, &hfrms);
if (!sret)
goto leave;
}
else {
/* We are in the case where the anti-amplification limit will be
* reached after having sent this datagram or some handshake frames
* could not be allocated. There is no need to send more than one
* datagram.
*/
ipktns->tx.pto_probe = 1;
qc->iel->retrans_frms = &ifrms;
sret = qc_send_hdshk_pkts(qc, 0, qc->iel, NULL);
qc_free_frm_list(qc, &ifrms);
qc_free_frm_list(qc, &hfrms);
if (!sret)
goto leave;
break;
}
}
TRACE_STATE("no more need to probe Initial packet number space",
QUIC_EV_CONN_TXPKT, qc);
ipktns->flags &= ~QUIC_FL_PKTNS_PROBE_NEEDED;
if (hpktns)
hpktns->flags &= ~QUIC_FL_PKTNS_PROBE_NEEDED;
}
else {
int i;
if (hpktns && (hpktns->flags & QUIC_FL_PKTNS_PROBE_NEEDED)) {
hpktns->tx.pto_probe = 0;
for (i = 0; i < QUIC_MAX_NB_PTO_DGRAMS; i++) {
struct list frms1 = LIST_HEAD_INIT(frms1);
qc_prep_fast_retrans(qc, hpktns, &frms1, NULL);
TRACE_DEVEL("Avail. ack eliciting frames", QUIC_EV_CONN_FRMLIST, qc, &frms1);
if (!LIST_ISEMPTY(&frms1)) {
hpktns->tx.pto_probe = 1;
qc->hel->retrans_frms = &frms1;
sret = qc_send_hdshk_pkts(qc, 1, qc->hel, NULL);
qc_free_frm_list(qc, &frms1);
if (!sret)
goto leave;
}
}
TRACE_STATE("no more need to probe Handshake packet number space",
QUIC_EV_CONN_TXPKT, qc);
hpktns->flags &= ~QUIC_FL_PKTNS_PROBE_NEEDED;
}
else if (apktns && (apktns->flags & QUIC_FL_PKTNS_PROBE_NEEDED)) {
struct list frms2 = LIST_HEAD_INIT(frms2);
struct list frms1 = LIST_HEAD_INIT(frms1);
apktns->tx.pto_probe = 0;
qc_prep_fast_retrans(qc, apktns, &frms1, &frms2);
TRACE_PROTO("Avail. ack eliciting frames", QUIC_EV_CONN_FRMLIST, qc, &frms1);
TRACE_PROTO("Avail. ack eliciting frames", QUIC_EV_CONN_FRMLIST, qc, &frms2);
if (!LIST_ISEMPTY(&frms1)) {
apktns->tx.pto_probe = 1;
sret = qc_send_app_probing(qc, &frms1);
qc_free_frm_list(qc, &frms1);
if (!sret) {
qc_free_frm_list(qc, &frms2);
goto leave;
}
}
if (!LIST_ISEMPTY(&frms2)) {
apktns->tx.pto_probe = 1;
sret = qc_send_app_probing(qc, &frms2);
qc_free_frm_list(qc, &frms2);
if (!sret)
goto leave;
}
TRACE_STATE("no more need to probe 01RTT packet number space",
QUIC_EV_CONN_TXPKT, qc);
apktns->flags &= ~QUIC_FL_PKTNS_PROBE_NEEDED;
}
}
ret = 1;
leave:
TRACE_LEAVE(QUIC_EV_CONN_TXPKT, qc);
return ret;
}
/*
* Send a Version Negotiation packet on response to <pkt> on socket <fd> to
* address <addr>.
* Implementation of RFC9000 6. Version Negotiation
*
* TODO implement a rate-limiting sending of Version Negotiation packets
*
* Returns 0 on success else non-zero
*/
int send_version_negotiation(int fd, struct sockaddr_storage *addr,
struct quic_rx_packet *pkt)
{
char buf[256];
int ret = 0, i = 0, j;
uint32_t version;
const socklen_t addrlen = get_addr_len(addr);
TRACE_ENTER(QUIC_EV_CONN_TXPKT);
/*
* header form
* long header, fixed bit to 0 for Version Negotiation
*/
/* TODO: RAND_bytes() should be replaced? */
if (RAND_bytes((unsigned char *)buf, 1) != 1) {
TRACE_ERROR("RAND_bytes() error", QUIC_EV_CONN_TXPKT);
goto out;
}
buf[i++] |= '\x80';
/* null version for Version Negotiation */
buf[i++] = '\x00';
buf[i++] = '\x00';
buf[i++] = '\x00';
buf[i++] = '\x00';
/* source connection id */
buf[i++] = pkt->scid.len;
memcpy(&buf[i], pkt->scid.data, pkt->scid.len);
i += pkt->scid.len;
/* destination connection id */
buf[i++] = pkt->dcid.len;
memcpy(&buf[i], pkt->dcid.data, pkt->dcid.len);
i += pkt->dcid.len;
/* supported version */
for (j = 0; j < quic_versions_nb; j++) {
version = htonl(quic_versions[j].num);
memcpy(&buf[i], &version, sizeof(version));
i += sizeof(version);
}
if (sendto(fd, buf, i, 0, (struct sockaddr *)addr, addrlen) < 0)
goto out;
ret = 1;
out:
TRACE_LEAVE(QUIC_EV_CONN_TXPKT);
return !ret;
}
/* Send a stateless reset packet depending on <pkt> RX packet information
* from <fd> UDP socket to <dst>
* Return 1 if succeeded, 0 if not.
*/
int send_stateless_reset(struct listener *l, struct sockaddr_storage *dstaddr,
struct quic_rx_packet *rxpkt)
{
int ret = 0, pktlen, rndlen;
unsigned char pkt[64];
const socklen_t addrlen = get_addr_len(dstaddr);
struct proxy *prx;
struct quic_counters *prx_counters;
TRACE_ENTER(QUIC_EV_STATELESS_RST);
prx = l->bind_conf->frontend;
prx_counters = EXTRA_COUNTERS_GET(prx->extra_counters_fe, &quic_stats_module);
/* 10.3 Stateless Reset (https://www.rfc-editor.org/rfc/rfc9000.html#section-10.3)
* The resulting minimum size of 21 bytes does not guarantee that a Stateless
* Reset is difficult to distinguish from other packets if the recipient requires
* the use of a connection ID. To achieve that end, the endpoint SHOULD ensure
* that all packets it sends are at least 22 bytes longer than the minimum
* connection ID length that it requests the peer to include in its packets,
* adding PADDING frames as necessary. This ensures that any Stateless Reset
* sent by the peer is indistinguishable from a valid packet sent to the endpoint.
* An endpoint that sends a Stateless Reset in response to a packet that is
* 43 bytes or shorter SHOULD send a Stateless Reset that is one byte shorter
* than the packet it responds to.
*/
/* Note that we build at most a 42 bytes QUIC packet to mimic a short packet */
pktlen = rxpkt->len <= 43 ? rxpkt->len - 1 : 0;
pktlen = QUIC_MAX(QUIC_STATELESS_RESET_PACKET_MINLEN, pktlen);
rndlen = pktlen - QUIC_STATELESS_RESET_TOKEN_LEN;
/* Put a header of random bytes */
/* TODO: RAND_bytes() should be replaced */
if (RAND_bytes(pkt, rndlen) != 1) {
TRACE_ERROR("RAND_bytes() failed", QUIC_EV_STATELESS_RST);
goto leave;
}
/* Clear the most significant bit, and set the second one */
*pkt = (*pkt & ~0x80) | 0x40;
if (!quic_stateless_reset_token_cpy(pkt + rndlen, QUIC_STATELESS_RESET_TOKEN_LEN,
rxpkt->dcid.data, rxpkt->dcid.len))
goto leave;
if (sendto(l->rx.fd, pkt, pktlen, 0, (struct sockaddr *)dstaddr, addrlen) < 0)
goto leave;
ret = 1;
HA_ATOMIC_INC(&prx_counters->stateless_reset_sent);
TRACE_PROTO("stateless reset sent", QUIC_EV_STATELESS_RST, NULL, &rxpkt->dcid);
leave:
TRACE_LEAVE(QUIC_EV_STATELESS_RST);
return ret;
}
/* Return the long packet type matching with <qv> version and <type> */
static inline int quic_pkt_type(int type, uint32_t version)
{
if (version != QUIC_PROTOCOL_VERSION_2)
return type;
switch (type) {
case QUIC_PACKET_TYPE_INITIAL:
return 1;
case QUIC_PACKET_TYPE_0RTT:
return 2;
case QUIC_PACKET_TYPE_HANDSHAKE:
return 3;
case QUIC_PACKET_TYPE_RETRY:
return 0;
}
return -1;
}
/* Generate a Retry packet and send it on <fd> socket to <addr> in response to
* the Initial <pkt> packet.
*
* Returns 0 on success else non-zero.
*/
int send_retry(int fd, struct sockaddr_storage *addr,
struct quic_rx_packet *pkt, const struct quic_version *qv)
{
int ret = 0;
unsigned char buf[128];
int i = 0, token_len;
const socklen_t addrlen = get_addr_len(addr);
struct quic_cid scid;
TRACE_ENTER(QUIC_EV_CONN_TXPKT);
/* long header(1) | fixed bit(1) | packet type QUIC_PACKET_TYPE_RETRY(2) | unused random bits(4)*/
buf[i++] = (QUIC_PACKET_LONG_HEADER_BIT | QUIC_PACKET_FIXED_BIT) |
(quic_pkt_type(QUIC_PACKET_TYPE_RETRY, qv->num) << QUIC_PACKET_TYPE_SHIFT) |
statistical_prng_range(16);
/* version */
write_n32(&buf[i], qv->num);
i += sizeof(uint32_t);
/* Use the SCID from <pkt> for Retry DCID. */
buf[i++] = pkt->scid.len;
memcpy(&buf[i], pkt->scid.data, pkt->scid.len);
i += pkt->scid.len;
/* Generate a new CID to be used as SCID for the Retry packet. */
scid.len = QUIC_HAP_CID_LEN;
/* TODO: RAND_bytes() should be replaced */
if (RAND_bytes(scid.data, scid.len) != 1) {
TRACE_ERROR("RAND_bytes() failed", QUIC_EV_CONN_TXPKT);
goto out;
}
buf[i++] = scid.len;
memcpy(&buf[i], scid.data, scid.len);
i += scid.len;
/* token */
if (!(token_len = quic_generate_retry_token(&buf[i], sizeof(buf) - i, qv->num,
&pkt->dcid, &pkt->scid, addr))) {
TRACE_ERROR("quic_generate_retry_token() failed", QUIC_EV_CONN_TXPKT);
goto out;
}
i += token_len;
/* token integrity tag */
if ((sizeof(buf) - i < QUIC_TLS_TAG_LEN) ||
!quic_tls_generate_retry_integrity_tag(pkt->dcid.data,
pkt->dcid.len, buf, i, qv)) {
TRACE_ERROR("quic_tls_generate_retry_integrity_tag() failed", QUIC_EV_CONN_TXPKT);
goto out;
}
i += QUIC_TLS_TAG_LEN;
if (sendto(fd, buf, i, 0, (struct sockaddr *)addr, addrlen) < 0) {
TRACE_ERROR("quic_tls_generate_retry_integrity_tag() failed", QUIC_EV_CONN_TXPKT);
goto out;
}
ret = 1;
out:
TRACE_LEAVE(QUIC_EV_CONN_TXPKT);
return !ret;
}
/* Write a 32-bits integer to a buffer with <buf> as address.
* Make <buf> point to the data after this 32-buts value if succeeded.
* Note that these 32-bits integers are networkg bytes ordered.
* Returns 0 if failed (not enough room in the buffer), 1 if succeeded.
*/
static inline int quic_write_uint32(unsigned char **buf,
const unsigned char *end, uint32_t val)
{
if (end - *buf < sizeof val)
return 0;
*(uint32_t *)*buf = htonl(val);
*buf += sizeof val;
return 1;
}
/* Return the maximum number of bytes we must use to completely fill a
* buffer with <sz> as size for a data field of bytes prefixed by its QUIC
* variable-length (may be 0).
* Also put in <*len_sz> the size of this QUIC variable-length.
* So after returning from this function we have : <*len_sz> + <ret> <= <sz>
* (<*len_sz> = { max(i), i + ret <= <sz> }) .
*/
static inline size_t max_available_room(size_t sz, size_t *len_sz)
{
size_t sz_sz, ret;
size_t diff;
sz_sz = quic_int_getsize(sz);
if (sz <= sz_sz)
return 0;
ret = sz - sz_sz;
*len_sz = quic_int_getsize(ret);
/* Difference between the two sizes. Note that <sz_sz> >= <*len_sz>. */
diff = sz_sz - *len_sz;
if (unlikely(diff > 0)) {
/* Let's try to take into an account remaining bytes.
*
* <----------------> <sz_sz>
* <--------------><--------> +----> <max_int>
* <ret> <len_sz> |
* +---------------------------+-----------....
* <--------------------------------> <sz>
*/
size_t max_int = quic_max_int(*len_sz);
if (max_int + *len_sz <= sz)
ret = max_int;
else
ret = sz - diff;
}
return ret;
}
/* This function computes the maximum data we can put into a buffer with <sz> as
* size prefixed with a variable-length field "Length" whose value is the
* remaining data length, already filled of <ilen> bytes which must be taken
* into an account by "Length" field, and finally followed by the data we want
* to put in this buffer prefixed again by a variable-length field.
* <sz> is the size of the buffer to fill.
* <ilen> the number of bytes already put after the "Length" field.
* <dlen> the number of bytes we want to at most put in the buffer.
* Also set <*dlen_sz> to the size of the data variable-length we want to put in
* the buffer. This is typically this function which must be used to fill as
* much as possible a QUIC packet made of only one CRYPTO or STREAM frames.
* Returns this computed size if there is enough room in the buffer, 0 if not.
*/
static inline size_t max_stream_data_size(size_t sz, size_t ilen, size_t dlen)
{
size_t ret, len_sz, dlen_sz;
/*
* The length of variable-length QUIC integers are powers of two.
* Look for the first 3length" field value <len_sz> which match our need.
* As we must put <ilen> bytes in our buffer, the minimum value for
* <len_sz> is the number of bytes required to encode <ilen>.
*/
for (len_sz = quic_int_getsize(ilen);
len_sz <= QUIC_VARINT_MAX_SIZE;
len_sz <<= 1) {
if (sz < len_sz + ilen)
return 0;
ret = max_available_room(sz - len_sz - ilen, &dlen_sz);
if (!ret)
return 0;
/* Check that <*len_sz> matches <ret> value */
if (len_sz + ilen + dlen_sz + ret <= quic_max_int(len_sz))
return ret < dlen ? ret : dlen;
}
return 0;
}
/* Return the length in bytes of <pn> packet number depending on
* <largest_acked_pn> the largest ackownledged packet number.
*/
static inline size_t quic_packet_number_length(int64_t pn,
int64_t largest_acked_pn)
{
int64_t max_nack_pkts;
/* About packet number encoding, the RFC says:
* The sender MUST use a packet number size able to represent more than
* twice as large a range than the difference between the largest
* acknowledged packet and packet number being sent.
*/
max_nack_pkts = 2 * (pn - largest_acked_pn) + 1;
if (max_nack_pkts > 0xffffff)
return 4;
if (max_nack_pkts > 0xffff)
return 3;
if (max_nack_pkts > 0xff)
return 2;
return 1;
}
/* Encode <pn> packet number with <pn_len> as length in byte into a buffer with
* <buf> as current copy address and <end> as pointer to one past the end of
* this buffer. This is the responsibility of the caller to check there is
* enough room in the buffer to copy <pn_len> bytes.
* Never fails.
*/
static inline int quic_packet_number_encode(unsigned char **buf,
const unsigned char *end,
uint64_t pn, size_t pn_len)
{
if (end - *buf < pn_len)
return 0;
/* Encode the packet number. */
switch (pn_len) {
case 1:
**buf = pn;
break;
case 2:
write_n16(*buf, pn);
break;
case 3:
(*buf)[0] = pn >> 16;
(*buf)[1] = pn >> 8;
(*buf)[2] = pn;
break;
case 4:
write_n32(*buf, pn);
break;
}
*buf += pn_len;
return 1;
}
/* This function builds into a buffer at <pos> position a QUIC long packet header,
* <end> being one byte past the end of this buffer.
* Return 1 if enough room to build this header, 0 if not.
*/
static int quic_build_packet_long_header(unsigned char **pos, const unsigned char *end,
int type, size_t pn_len,
struct quic_conn *qc, const struct quic_version *ver)
{
int ret = 0;
TRACE_ENTER(QUIC_EV_CONN_LPKT, qc);
if (end - *pos < sizeof ver->num + qc->dcid.len + qc->scid.len + 3) {
TRACE_DEVEL("not enough room", QUIC_EV_CONN_LPKT, qc);
goto leave;
}
type = quic_pkt_type(type, ver->num);
/* #0 byte flags */
*(*pos)++ = QUIC_PACKET_FIXED_BIT | QUIC_PACKET_LONG_HEADER_BIT |
(type << QUIC_PACKET_TYPE_SHIFT) | (pn_len - 1);
/* Version */
quic_write_uint32(pos, end, ver->num);
*(*pos)++ = qc->dcid.len;
/* Destination connection ID */
if (qc->dcid.len) {
memcpy(*pos, qc->dcid.data, qc->dcid.len);
*pos += qc->dcid.len;
}
/* Source connection ID */
*(*pos)++ = qc->scid.len;
if (qc->scid.len) {
memcpy(*pos, qc->scid.data, qc->scid.len);
*pos += qc->scid.len;
}
ret = 1;
leave:
TRACE_LEAVE(QUIC_EV_CONN_LPKT, qc);
return ret;
}
/* This function builds into a buffer at <pos> position a QUIC short packet header,
* <end> being one byte past the end of this buffer.
* Return 1 if enough room to build this header, 0 if not.
*/
static int quic_build_packet_short_header(unsigned char **pos, const unsigned char *end,
size_t pn_len, struct quic_conn *qc,
unsigned char tls_flags)
{
int ret = 0;
unsigned char spin_bit =
(qc->flags & QUIC_FL_CONN_SPIN_BIT) ? QUIC_PACKET_SPIN_BIT : 0;
TRACE_ENTER(QUIC_EV_CONN_TXPKT, qc);
if (end - *pos < 1 + qc->dcid.len) {
TRACE_DEVEL("not enough room", QUIC_EV_CONN_LPKT, qc);
goto leave;
}
/* #0 byte flags */
*(*pos)++ = QUIC_PACKET_FIXED_BIT | spin_bit |
((tls_flags & QUIC_FL_TLS_KP_BIT_SET) ? QUIC_PACKET_KEY_PHASE_BIT : 0) | (pn_len - 1);
/* Destination connection ID */
if (qc->dcid.len) {
memcpy(*pos, qc->dcid.data, qc->dcid.len);
*pos += qc->dcid.len;
}
ret = 1;
leave:
TRACE_LEAVE(QUIC_EV_CONN_TXPKT, qc);
return ret;
}
/* Apply QUIC header protection to the packet with <pos> as first byte address,
* <pn> as address of the Packet number field, <pnlen> being this field length
* with <aead> as AEAD cipher and <key> as secret key.
*
* TODO no error is expected as encryption is done in place but encryption
* manual is unclear. <fail> will be set to true if an error is detected.
*/
void quic_apply_header_protection(struct quic_conn *qc, unsigned char *pos,
unsigned char *pn, size_t pnlen,
struct quic_tls_ctx *tls_ctx, int *fail)
{
int i;
/* We need an IV of at least 5 bytes: one byte for bytes #0
* and at most 4 bytes for the packet number
*/
unsigned char mask[5] = {0};
EVP_CIPHER_CTX *aes_ctx = tls_ctx->tx.hp_ctx;
TRACE_ENTER(QUIC_EV_CONN_TXPKT, qc);
*fail = 0;
if (!quic_tls_aes_encrypt(mask, pn + QUIC_PACKET_PN_MAXLEN, sizeof mask, aes_ctx)) {
TRACE_ERROR("could not apply header protection", QUIC_EV_CONN_TXPKT, qc);
*fail = 1;
goto out;
}
*pos ^= mask[0] & (*pos & QUIC_PACKET_LONG_HEADER_BIT ? 0xf : 0x1f);
for (i = 0; i < pnlen; i++)
pn[i] ^= mask[i + 1];
out:
TRACE_LEAVE(QUIC_EV_CONN_TXPKT, qc);
}
/* Prepare into <outlist> as most as possible ack-eliciting frame from their
* <inlist> prebuilt frames for <qel> encryption level to be encoded in a buffer
* with <room> as available room, and <*len> the packet Length field initialized
* with the number of bytes already present in this buffer which must be taken
* into an account for the Length packet field value. <headlen> is the number of
* bytes already present in this packet before building frames.
*
* Update consequently <*len> to reflect the size of these frames built
* by this function. Also attach these frames to <l> frame list.
* Return 1 if at least one ack-eleciting frame could be built, 0 if not.
*/
static int qc_build_frms(struct list *outlist, struct list *inlist,
size_t room, size_t *len, size_t headlen,
struct quic_enc_level *qel,
struct quic_conn *qc)
{
int ret;
struct quic_frame *cf, *cfbak;
TRACE_ENTER(QUIC_EV_CONN_BCFRMS, qc);
ret = 0;
if (*len > room)
goto leave;
/* If we are not probing we must take into an account the congestion
* control window.
*/
if (!qel->pktns->tx.pto_probe) {
size_t remain = quic_cc_path_prep_data(qc->path);
if (headlen > remain)
goto leave;
room = QUIC_MIN(room, remain - headlen);
}
TRACE_PROTO("TX frms build (headlen)",
QUIC_EV_CONN_BCFRMS, qc, &headlen);
/* NOTE: switch/case block inside a loop, a successful status must be
* returned by this function only if at least one frame could be built
* in the switch/case block.
*/
list_for_each_entry_safe(cf, cfbak, inlist, list) {
/* header length, data length, frame length. */
size_t hlen, dlen, dlen_sz, avail_room, flen;
if (!room)
break;
switch (cf->type) {
case QUIC_FT_CRYPTO:
TRACE_DEVEL(" New CRYPTO frame build (room, len)",
QUIC_EV_CONN_BCFRMS, qc, &room, len);
/* Compute the length of this CRYPTO frame header */
hlen = 1 + quic_int_getsize(cf->crypto.offset);
/* Compute the data length of this CRyPTO frame. */
dlen = max_stream_data_size(room, *len + hlen, cf->crypto.len);
TRACE_DEVEL(" CRYPTO data length (hlen, crypto.len, dlen)",
QUIC_EV_CONN_BCFRMS, qc, &hlen, &cf->crypto.len, &dlen);
if (!dlen)
continue;
/* CRYPTO frame length. */
flen = hlen + quic_int_getsize(dlen) + dlen;
TRACE_DEVEL(" CRYPTO frame length (flen)",
QUIC_EV_CONN_BCFRMS, qc, &flen);
/* Add the CRYPTO data length and its encoded length to the packet
* length and the length of this length.
*/
*len += flen;
room -= flen;
if (dlen == cf->crypto.len) {
/* <cf> CRYPTO data have been consumed. */
LIST_DEL_INIT(&cf->list);
LIST_APPEND(outlist, &cf->list);
}
else {
struct quic_frame *new_cf;
new_cf = qc_frm_alloc(QUIC_FT_CRYPTO);
if (!new_cf) {
TRACE_ERROR("No memory for new crypto frame", QUIC_EV_CONN_BCFRMS, qc);
continue;
}
new_cf->crypto.len = dlen;
new_cf->crypto.offset = cf->crypto.offset;
new_cf->crypto.qel = qel;
TRACE_DEVEL("split frame", QUIC_EV_CONN_PRSAFRM, qc, new_cf);
if (cf->origin) {
TRACE_DEVEL("duplicated frame", QUIC_EV_CONN_PRSAFRM, qc);
/* This <cf> frame was duplicated */
LIST_APPEND(&cf->origin->reflist, &new_cf->ref);
new_cf->origin = cf->origin;
/* Detach the remaining CRYPTO frame from its original frame */
LIST_DEL_INIT(&cf->ref);
cf->origin = NULL;
}
LIST_APPEND(outlist, &new_cf->list);
/* Consume <dlen> bytes of the current frame. */
cf->crypto.len -= dlen;
cf->crypto.offset += dlen;
}
break;
case QUIC_FT_STREAM_8 ... QUIC_FT_STREAM_F:
if (cf->stream.dup) {
struct eb64_node *node = NULL;
struct qc_stream_desc *stream_desc = NULL;
struct qf_stream *strm_frm = &cf->stream;
/* As this frame has been already lost, ensure the stream is always
* available or the range of this frame is not consumed before
* resending it.
*/
node = eb64_lookup(&qc->streams_by_id, strm_frm->id);
if (!node) {
TRACE_DEVEL("released stream", QUIC_EV_CONN_PRSAFRM, qc, cf);
qc_frm_free(qc, &cf);
continue;
}
stream_desc = eb64_entry(node, struct qc_stream_desc, by_id);
if (strm_frm->offset.key + strm_frm->len <= stream_desc->ack_offset) {
TRACE_DEVEL("ignored frame frame in already acked range",
QUIC_EV_CONN_PRSAFRM, qc, cf);
qc_frm_free(qc, &cf);
continue;
}
else if (strm_frm->offset.key < stream_desc->ack_offset) {
uint64_t diff = stream_desc->ack_offset - strm_frm->offset.key;
qc_stream_frm_mv_fwd(cf, diff);
TRACE_DEVEL("updated partially acked frame",
QUIC_EV_CONN_PRSAFRM, qc, cf);
}
}
/* Note that these frames are accepted in short packets only without
* "Length" packet field. Here, <*len> is used only to compute the
* sum of the lengths of the already built frames for this packet.
*
* Compute the length of this STREAM frame "header" made a all the field
* excepting the variable ones. Note that +1 is for the type of this frame.
*/
hlen = 1 + quic_int_getsize(cf->stream.id) +
((cf->type & QUIC_STREAM_FRAME_TYPE_OFF_BIT) ? quic_int_getsize(cf->stream.offset.key) : 0);
/* Compute the data length of this STREAM frame. */
avail_room = room - hlen - *len;
if ((ssize_t)avail_room <= 0)
continue;
TRACE_DEVEL(" New STREAM frame build (room, len)",
QUIC_EV_CONN_BCFRMS, qc, &room, len);
/* hlen contains STREAM id and offset. Ensure there is
* enough room for length field.
*/
if (cf->type & QUIC_STREAM_FRAME_TYPE_LEN_BIT) {
dlen = QUIC_MIN((uint64_t)max_available_room(avail_room, &dlen_sz),
cf->stream.len);
dlen_sz = quic_int_getsize(dlen);
flen = hlen + dlen_sz + dlen;
}
else {
dlen = QUIC_MIN((uint64_t)avail_room, cf->stream.len);
flen = hlen + dlen;
}
if (cf->stream.len && !dlen) {
/* Only a small gap is left on buffer, not
* enough to encode the STREAM data length.
*/
continue;
}
TRACE_DEVEL(" STREAM data length (hlen, stream.len, dlen)",
QUIC_EV_CONN_BCFRMS, qc, &hlen, &cf->stream.len, &dlen);
TRACE_DEVEL(" STREAM frame length (flen)",
QUIC_EV_CONN_BCFRMS, qc, &flen);
/* Add the STREAM data length and its encoded length to the packet
* length and the length of this length.
*/
*len += flen;
room -= flen;
if (dlen == cf->stream.len) {
/* <cf> STREAM data have been consumed. */
LIST_DEL_INIT(&cf->list);
LIST_APPEND(outlist, &cf->list);
/* Do not notify MUX on retransmission. */
if (qc->flags & QUIC_FL_CONN_TX_MUX_CONTEXT) {
qcc_streams_sent_done(cf->stream.stream->ctx,
cf->stream.len,
cf->stream.offset.key);
}
}
else {
struct quic_frame *new_cf;
struct buffer cf_buf;
new_cf = qc_frm_alloc(cf->type);
if (!new_cf) {
TRACE_ERROR("No memory for new STREAM frame", QUIC_EV_CONN_BCFRMS, qc);
continue;
}
new_cf->stream.stream = cf->stream.stream;
new_cf->stream.buf = cf->stream.buf;
new_cf->stream.id = cf->stream.id;
new_cf->stream.offset = cf->stream.offset;
new_cf->stream.len = dlen;
new_cf->type |= QUIC_STREAM_FRAME_TYPE_LEN_BIT;
/* FIN bit reset */
new_cf->type &= ~QUIC_STREAM_FRAME_TYPE_FIN_BIT;
new_cf->stream.data = cf->stream.data;
new_cf->stream.dup = cf->stream.dup;
TRACE_DEVEL("split frame", QUIC_EV_CONN_PRSAFRM, qc, new_cf);
if (cf->origin) {
TRACE_DEVEL("duplicated frame", QUIC_EV_CONN_PRSAFRM, qc);
/* This <cf> frame was duplicated */
LIST_APPEND(&cf->origin->reflist, &new_cf->ref);
new_cf->origin = cf->origin;
/* Detach this STREAM frame from its origin */
LIST_DEL_INIT(&cf->ref);
cf->origin = NULL;
}
LIST_APPEND(outlist, &new_cf->list);
cf->type |= QUIC_STREAM_FRAME_TYPE_OFF_BIT;
/* Consume <dlen> bytes of the current frame. */
cf_buf = b_make(b_orig(cf->stream.buf),
b_size(cf->stream.buf),
(char *)cf->stream.data - b_orig(cf->stream.buf), 0);
cf->stream.len -= dlen;
cf->stream.offset.key += dlen;
cf->stream.data = (unsigned char *)b_peek(&cf_buf, dlen);
/* Do not notify MUX on retransmission. */
if (qc->flags & QUIC_FL_CONN_TX_MUX_CONTEXT) {
qcc_streams_sent_done(new_cf->stream.stream->ctx,
new_cf->stream.len,
new_cf->stream.offset.key);
}
}
/* TODO the MUX is notified about the frame sending via
* previous qcc_streams_sent_done call. However, the
* sending can fail later, for example if the sendto
* system call returns an error. As the MUX has been
* notified, the transport layer is responsible to
* bufferize and resent the announced data later.
*/
break;
default:
flen = qc_frm_len(cf);
BUG_ON(!flen);
if (flen > room)
continue;
*len += flen;
room -= flen;
LIST_DEL_INIT(&cf->list);
LIST_APPEND(outlist, &cf->list);
break;
}
/* Successful status as soon as a frame could be built */
ret = 1;
}
leave:
TRACE_LEAVE(QUIC_EV_CONN_BCFRMS, qc);
return ret;
}
/* Generate a CONNECTION_CLOSE frame for <qc> on <qel> encryption level. <out>
* is used as return parameter and should be zero'ed by the caller.
*/
static void qc_build_cc_frm(struct quic_conn *qc, struct quic_enc_level *qel,
struct quic_frame *out)
{
/* TODO improve CONNECTION_CLOSE on Initial/Handshake encryption levels
*
* A CONNECTION_CLOSE frame should be sent in several packets with
* different encryption levels depending on the client context. This is
* to ensure that the client can decrypt it. See RFC 9000 10.2.3 for
* more details on how to implement it.
*/
TRACE_ENTER(QUIC_EV_CONN_BFRM, qc);
if (qc->err.app) {
if (unlikely(qel == qc->iel || qel == qc->hel)) {
/* RFC 9000 10.2.3. Immediate Close during the Handshake
*
* Sending a CONNECTION_CLOSE of type 0x1d in an Initial or Handshake
* packet could expose application state or be used to alter application
* state. 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.
*/
out->type = QUIC_FT_CONNECTION_CLOSE;
out->connection_close.error_code = QC_ERR_APPLICATION_ERROR;
out->connection_close.reason_phrase_len = 0;
}
else {
out->type = QUIC_FT_CONNECTION_CLOSE_APP;
out->connection_close_app.error_code = qc->err.code;
out->connection_close_app.reason_phrase_len = 0;
}
}
else {
out->type = QUIC_FT_CONNECTION_CLOSE;
out->connection_close.error_code = qc->err.code;
out->connection_close.reason_phrase_len = 0;
}
TRACE_LEAVE(QUIC_EV_CONN_BFRM, qc);
}
/* Returns the <ack_delay> field value in microsecond to be set in an ACK frame
* depending on the time the packet with a new largest packet number was received.
*/
static inline uint64_t quic_compute_ack_delay_us(unsigned int time_received,
struct quic_conn *conn)
{
return ((now_ms - time_received) * 1000) >> conn->tx.params.ack_delay_exponent;
}
/* This function builds a clear packet from <pkt> information (its type)
* into a buffer with <pos> as position pointer and <qel> as QUIC TLS encryption
* level for <conn> QUIC connection and <qel> as QUIC TLS encryption level,
* filling the buffer with as much frames as possible from <frms> list of
* prebuilt frames.
* The trailing QUIC_TLS_TAG_LEN bytes of this packet are not built. But they are
* reserved so that to ensure there is enough room to build this AEAD TAG after
* having returned from this function.
* This function also updates the value of <buf_pn> pointer to point to the packet
* number field in this packet. <pn_len> will also have the packet number
* length as value.
*
* Return 1 if succeeded (enough room to buile this packet), O if not.
*/
static int qc_do_build_pkt(unsigned char *pos, const unsigned char *end,
size_t dglen, struct quic_tx_packet *pkt,
int64_t pn, size_t *pn_len, unsigned char **buf_pn,
int must_ack, int padding, int cc, int probe,
struct quic_enc_level *qel, struct quic_conn *qc,
const struct quic_version *ver, struct list *frms)
{
unsigned char *beg, *payload;
size_t len, len_sz, len_frms, padding_len;
struct quic_frame frm;
struct quic_frame ack_frm;
struct quic_frame cc_frm;
size_t ack_frm_len, head_len;
int64_t rx_largest_acked_pn;
int add_ping_frm;
struct list frm_list = LIST_HEAD_INIT(frm_list);
struct quic_frame *cf;
int ret = 0;
TRACE_ENTER(QUIC_EV_CONN_TXPKT, qc);
/* Length field value with CRYPTO frames if present. */
len_frms = 0;
beg = pos;
/* When not probing, and no immediate close is required, reduce the size of this
* buffer to respect the congestion controller window.
* This size will be limited if we have ack-eliciting frames to send from <frms>.
*/
if (!probe && !LIST_ISEMPTY(frms) && !cc) {
size_t path_room;
path_room = quic_cc_path_prep_data(qc->path);
if (end - beg > path_room)
end = beg + path_room;
}
/* Ensure there is enough room for the TLS encryption tag and a zero token
* length field if any.
*/
if (end - pos < QUIC_TLS_TAG_LEN +
(pkt->type == QUIC_PACKET_TYPE_INITIAL ? 1 : 0))
goto no_room;
end -= QUIC_TLS_TAG_LEN;
rx_largest_acked_pn = qel->pktns->rx.largest_acked_pn;
/* packet number length */
*pn_len = quic_packet_number_length(pn, rx_largest_acked_pn);
/* Build the header */
if ((pkt->type == QUIC_PACKET_TYPE_SHORT &&
!quic_build_packet_short_header(&pos, end, *pn_len, qc, qel->tls_ctx.flags)) ||
(pkt->type != QUIC_PACKET_TYPE_SHORT &&
!quic_build_packet_long_header(&pos, end, pkt->type, *pn_len, qc, ver)))
goto no_room;
/* Encode the token length (0) for an Initial packet. */
if (pkt->type == QUIC_PACKET_TYPE_INITIAL) {
if (end <= pos)
goto no_room;
*pos++ = 0;
}
head_len = pos - beg;
/* Build an ACK frame if required. */
ack_frm_len = 0;
/* Do not ack and probe at the same time. */
if ((must_ack || (qel->pktns->flags & QUIC_FL_PKTNS_ACK_REQUIRED)) && !qel->pktns->tx.pto_probe) {
struct quic_arngs *arngs = &qel->pktns->rx.arngs;
BUG_ON(eb_is_empty(&qel->pktns->rx.arngs.root));
ack_frm.type = QUIC_FT_ACK;
ack_frm.tx_ack.arngs = arngs;
if (qel->pktns->flags & QUIC_FL_PKTNS_NEW_LARGEST_PN) {
qel->pktns->tx.ack_delay =
quic_compute_ack_delay_us(qel->pktns->rx.largest_time_received, qc);
qel->pktns->flags &= ~QUIC_FL_PKTNS_NEW_LARGEST_PN;
}
ack_frm.tx_ack.ack_delay = qel->pktns->tx.ack_delay;
/* XXX BE CAREFUL XXX : here we reserved at least one byte for the
* smallest frame (PING) and <*pn_len> more for the packet number. Note
* that from here, we do not know if we will have to send a PING frame.
* This will be decided after having computed the ack-eliciting frames
* to be added to this packet.
*/
if (end - pos <= 1 + *pn_len)
goto no_room;
ack_frm_len = qc_frm_len(&ack_frm);
if (ack_frm_len > end - 1 - *pn_len - pos)
goto no_room;
}
/* Length field value without the ack-eliciting frames. */
len = ack_frm_len + *pn_len;
len_frms = 0;
if (!cc && !LIST_ISEMPTY(frms)) {
ssize_t room = end - pos;
TRACE_PROTO("Avail. ack eliciting frames", QUIC_EV_CONN_FRMLIST, qc, frms);
/* Initialize the length of the frames built below to <len>.
* If any frame could be successfully built by qc_build_frms(),
* we will have len_frms > len.
*/
len_frms = len;
if (!qc_build_frms(&frm_list, frms,
end - pos, &len_frms, pos - beg, qel, qc)) {
TRACE_PROTO("Not enough room", QUIC_EV_CONN_TXPKT,
qc, NULL, NULL, &room);
if (padding) {
len_frms = 0;
goto comp_pkt_len;
}
if (!ack_frm_len && !qel->pktns->tx.pto_probe)
goto no_room;
}
}
comp_pkt_len:
/* Length (of the remaining data). Must not fail because, the buffer size
* has been checked above. Note that we have reserved QUIC_TLS_TAG_LEN bytes
* for the encryption tag. It must be taken into an account for the length
* of this packet.
*/
if (len_frms)
len = len_frms + QUIC_TLS_TAG_LEN;
else
len += QUIC_TLS_TAG_LEN;
/* CONNECTION_CLOSE frame */
if (cc) {
qc_build_cc_frm(qc, qel, &cc_frm);
len += qc_frm_len(&cc_frm);
}
add_ping_frm = 0;
padding_len = 0;
len_sz = quic_int_getsize(len);
/* Add this packet size to <dglen> */
dglen += head_len + len_sz + len;
/* Note that <padding> is true only when building an Handshake packet
* coalesced to an Initial packet.
*/
if (padding && dglen < QUIC_INITIAL_PACKET_MINLEN) {
/* This is a maximum padding size */
padding_len = QUIC_INITIAL_PACKET_MINLEN - dglen;
/* The length field value is of this packet is <len> + <padding_len>
* the size of which may be greater than the initial computed size
* <len_sz>. So, let's deduce the difference between these to packet
* sizes from <padding_len>.
*/
padding_len -= quic_int_getsize(len + padding_len) - len_sz;
len += padding_len;
}
else if (len_frms && len_frms < QUIC_PACKET_PN_MAXLEN) {
len += padding_len = QUIC_PACKET_PN_MAXLEN - len_frms;
}
else if (LIST_ISEMPTY(&frm_list)) {
if (qel->pktns->tx.pto_probe) {
/* If we cannot send a frame, we send a PING frame. */
add_ping_frm = 1;
len += 1;
dglen += 1;
/* Note that only we are in the case where this Initial packet
* is not coalesced to an Handshake packet. We must directly
* pad the datragram.
*/
if (pkt->type == QUIC_PACKET_TYPE_INITIAL) {
if (dglen < QUIC_INITIAL_PACKET_MINLEN) {
padding_len = QUIC_INITIAL_PACKET_MINLEN - dglen;
padding_len -= quic_int_getsize(len + padding_len) - len_sz;
len += padding_len;
}
}
else {
/* Note that +1 is for the PING frame */
if (*pn_len + 1 < QUIC_PACKET_PN_MAXLEN)
len += padding_len = QUIC_PACKET_PN_MAXLEN - *pn_len - 1;
}
}
else {
/* If there is no frame at all to follow, add at least a PADDING frame. */
if (!ack_frm_len && !cc)
len += padding_len = QUIC_PACKET_PN_MAXLEN - *pn_len;
}
}
if (pkt->type != QUIC_PACKET_TYPE_SHORT && !quic_enc_int(&pos, end, len))
goto no_room;
/* Packet number field address. */
*buf_pn = pos;
/* Packet number encoding. */
if (!quic_packet_number_encode(&pos, end, pn, *pn_len))
goto no_room;
/* payload building (ack-eliciting or not frames) */
payload = pos;
if (ack_frm_len) {
if (!qc_build_frm(&pos, end, &ack_frm, pkt, qc))
goto no_room;
pkt->largest_acked_pn = quic_pktns_get_largest_acked_pn(qel->pktns);
pkt->flags |= QUIC_FL_TX_PACKET_ACK;
}
/* Ack-eliciting frames */
if (!LIST_ISEMPTY(&frm_list)) {
struct quic_frame *tmp_cf;
list_for_each_entry_safe(cf, tmp_cf, &frm_list, list) {
if (!qc_build_frm(&pos, end, cf, pkt, qc)) {
ssize_t room = end - pos;
TRACE_PROTO("Not enough room", QUIC_EV_CONN_TXPKT,
qc, NULL, NULL, &room);
/* Note that <cf> was added from <frms> to <frm_list> list by
* qc_build_frms().
*/
LIST_DEL_INIT(&cf->list);
LIST_INSERT(frms, &cf->list);
continue;
}
quic_tx_packet_refinc(pkt);
cf->pkt = pkt;
}
}
/* Build a PING frame if needed. */
if (add_ping_frm) {
frm.type = QUIC_FT_PING;
if (!qc_build_frm(&pos, end, &frm, pkt, qc))
goto no_room;
}
/* Build a CONNECTION_CLOSE frame if needed. */
if (cc) {
if (!qc_build_frm(&pos, end, &cc_frm, pkt, qc))
goto no_room;
pkt->flags |= QUIC_FL_TX_PACKET_CC;
}
/* Build a PADDING frame if needed. */
if (padding_len) {
frm.type = QUIC_FT_PADDING;
frm.padding.len = padding_len;
if (!qc_build_frm(&pos, end, &frm, pkt, qc))
goto no_room;
}
if (pos == payload) {
/* No payload was built because of congestion control */
TRACE_PROTO("limited by congestion control", QUIC_EV_CONN_TXPKT, qc);
goto no_room;
}
/* If this packet is ack-eliciting and we are probing let's
* decrement the PTO probe counter.
*/
if ((pkt->flags & QUIC_FL_TX_PACKET_ACK_ELICITING) &&
qel->pktns->tx.pto_probe)
qel->pktns->tx.pto_probe--;
pkt->len = pos - beg;
LIST_SPLICE(&pkt->frms, &frm_list);
ret = 1;
TRACE_PROTO("Packet ack-eliciting frames", QUIC_EV_CONN_TXPKT, qc, pkt);
leave:
TRACE_LEAVE(QUIC_EV_CONN_TXPKT, qc);
return ret;
no_room:
/* Replace the pre-built frames which could not be add to this packet */
LIST_SPLICE(frms, &frm_list);
TRACE_PROTO("Remaining ack-eliciting frames", QUIC_EV_CONN_FRMLIST, qc, frms);
goto leave;
}
static inline void quic_tx_packet_init(struct quic_tx_packet *pkt, int type)
{
pkt->type = type;
pkt->len = 0;
pkt->in_flight_len = 0;
pkt->pn_node.key = (uint64_t)-1;
LIST_INIT(&pkt->frms);
pkt->time_sent = TICK_ETERNITY;
pkt->next = NULL;
pkt->prev = NULL;
pkt->largest_acked_pn = -1;
pkt->flags = 0;
pkt->refcnt = 0;
}
/* Build a packet into a buffer at <pos> position, <end> pointing to one byte past
* the end of this buffer, with <pkt_type> as packet type for <qc> QUIC connection
* at <qel> encryption level with <frms> list of prebuilt frames.
*
* Return -3 if the packet could not be allocated, -2 if could not be encrypted for
* any reason, -1 if there was not enough room to build a packet.
* XXX NOTE XXX
* If you provide provide qc_build_pkt() with a big enough buffer to build a packet as big as
* possible (to fill an MTU), the unique reason why this function may fail is the congestion
* control window limitation.
*/
static struct quic_tx_packet *qc_build_pkt(unsigned char **pos,
const unsigned char *end,
struct quic_enc_level *qel,
struct quic_tls_ctx *tls_ctx, struct list *frms,
struct quic_conn *qc, const struct quic_version *ver,
size_t dglen, int pkt_type, int must_ack,
int padding, int probe, int cc, int *err)
{
struct quic_tx_packet *ret_pkt = NULL;
/* The pointer to the packet number field. */
unsigned char *buf_pn;
unsigned char *first_byte, *last_byte, *payload;
int64_t pn;
size_t pn_len, payload_len, aad_len;
struct quic_tx_packet *pkt;
int encrypt_failure = 0;
TRACE_ENTER(QUIC_EV_CONN_TXPKT, qc);
TRACE_PROTO("TX pkt build", QUIC_EV_CONN_TXPKT, qc, NULL, qel);
*err = 0;
pkt = pool_alloc(pool_head_quic_tx_packet);
if (!pkt) {
TRACE_DEVEL("Not enough memory for a new packet", QUIC_EV_CONN_TXPKT, qc);
*err = -3;
goto err;
}
quic_tx_packet_init(pkt, pkt_type);
first_byte = *pos;
pn_len = 0;
buf_pn = NULL;
pn = qel->pktns->tx.next_pn + 1;
if (!qc_do_build_pkt(*pos, end, dglen, pkt, pn, &pn_len, &buf_pn,
must_ack, padding, cc, probe, qel, qc, ver, frms)) {
// trace already emitted by function above
*err = -1;
goto err;
}
last_byte = first_byte + pkt->len;
payload = buf_pn + pn_len;
payload_len = last_byte - payload;
aad_len = payload - first_byte;
quic_packet_encrypt(payload, payload_len, first_byte, aad_len, pn, tls_ctx, qc, &encrypt_failure);
if (encrypt_failure) {
/* TODO Unrecoverable failure, unencrypted data should be returned to the caller. */
WARN_ON("quic_packet_encrypt failure");
*err = -2;
goto err;
}
last_byte += QUIC_TLS_TAG_LEN;
pkt->len += QUIC_TLS_TAG_LEN;
quic_apply_header_protection(qc, first_byte, buf_pn, pn_len, tls_ctx, &encrypt_failure);
if (encrypt_failure) {
/* TODO Unrecoverable failure, unencrypted data should be returned to the caller. */
WARN_ON("quic_apply_header_protection failure");
*err = -2;
goto err;
}
/* Consume a packet number */
qel->pktns->tx.next_pn++;
qc->bytes.prep += pkt->len;
if (qc->bytes.prep >= 3 * qc->bytes.rx && !quic_peer_validated_addr(qc)) {
qc->flags |= QUIC_FL_CONN_ANTI_AMPLIFICATION_REACHED;
TRACE_PROTO("anti-amplification limit reached", QUIC_EV_CONN_TXPKT, qc);
}
/* Now that a correct packet is built, let us consume <*pos> buffer. */
*pos = last_byte;
/* Attach the built packet to its tree. */
pkt->pn_node.key = pn;
/* Set the packet in fligth length for in flight packet only. */
if (pkt->flags & QUIC_FL_TX_PACKET_IN_FLIGHT) {
pkt->in_flight_len = pkt->len;
qc->path->prep_in_flight += pkt->len;
}
/* Always reset this flag */
qc->flags &= ~QUIC_FL_CONN_IMMEDIATE_CLOSE;
if (pkt->flags & QUIC_FL_TX_PACKET_ACK) {
qel->pktns->flags &= ~QUIC_FL_PKTNS_ACK_REQUIRED;
qel->pktns->rx.nb_aepkts_since_last_ack = 0;
qc->flags &= ~QUIC_FL_CONN_ACK_TIMER_FIRED;
if (tick_isset(qc->ack_expire)) {
qc->ack_expire = TICK_ETERNITY;
qc->idle_timer_task->expire = qc->idle_expire;
task_queue(qc->idle_timer_task);
TRACE_PROTO("ack timer cancelled", QUIC_EV_CONN_IDLE_TIMER, qc);
}
}
pkt->pktns = qel->pktns;
ret_pkt = pkt;
leave:
TRACE_PROTO("TX pkt built", QUIC_EV_CONN_TXPKT, qc, ret_pkt);
TRACE_LEAVE(QUIC_EV_CONN_TXPKT, qc);
return ret_pkt;
err:
/* TODO: what about the frames which have been built
* for this packet.
*/
free_quic_tx_packet(qc, pkt);
goto leave;
}
/*
* Local variables:
* c-indent-level: 8
* c-basic-offset: 8
* End:
*/
Reference in New Issue View Git Blame Copy Permalink