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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/*
* DTLS Protocol
*/
#include "ssl.h"
#include "sslimpl.h"
#include "sslproto.h"
#include "dtls13con.h"
#ifndef PR_ARRAY_SIZE
#define PR_ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))
#endif
static SECStatus dtls_StartRetransmitTimer(sslSocket *ss);
static void dtls_RetransmitTimerExpiredCb(sslSocket *ss);
static SECStatus dtls_SendSavedWriteData(sslSocket *ss);
static void dtls_FinishedTimerCb(sslSocket *ss);
static void dtls_CancelAllTimers(sslSocket *ss);
/* -28 adjusts for the IP/UDP header */
static const PRUint16 COMMON_MTU_VALUES[] = {
1500 - 28, /* Ethernet MTU */
1280 - 28, /* IPv6 minimum MTU */
576 - 28, /* Common assumption */
256 - 28 /* We're in serious trouble now */
};
#define DTLS_COOKIE_BYTES 32
/* Maximum DTLS expansion = header + IV + max CBC padding +
* maximum MAC. */
#define DTLS_MAX_EXPANSION (DTLS_RECORD_HEADER_LENGTH + 16 + 16 + 32)
/* List copied from ssl3con.c:cipherSuites */
static const ssl3CipherSuite nonDTLSSuites[] = {
TLS_ECDHE_ECDSA_WITH_RC4_128_SHA,
TLS_ECDHE_RSA_WITH_RC4_128_SHA,
TLS_DHE_DSS_WITH_RC4_128_SHA,
TLS_ECDH_RSA_WITH_RC4_128_SHA,
TLS_ECDH_ECDSA_WITH_RC4_128_SHA,
TLS_RSA_WITH_RC4_128_MD5,
TLS_RSA_WITH_RC4_128_SHA,
0 /* End of list marker */
};
/* Map back and forth between TLS and DTLS versions in wire format.
* Mapping table is:
*
* TLS DTLS
* 1.1 (0302) 1.0 (feff)
* 1.2 (0303) 1.2 (fefd)
* 1.3 (0304) 1.3 (0304)
*/
SSL3ProtocolVersion
dtls_TLSVersionToDTLSVersion(SSL3ProtocolVersion tlsv)
{
if (tlsv == SSL_LIBRARY_VERSION_TLS_1_1) {
return SSL_LIBRARY_VERSION_DTLS_1_0_WIRE;
}
if (tlsv == SSL_LIBRARY_VERSION_TLS_1_2) {
return SSL_LIBRARY_VERSION_DTLS_1_2_WIRE;
}
if (tlsv == SSL_LIBRARY_VERSION_TLS_1_3) {
return SSL_LIBRARY_VERSION_DTLS_1_3_WIRE;
}
/* Anything else is an error, so return
* the invalid version 0xffff. */
return 0xffff;
}
/* Map known DTLS versions to known TLS versions.
* - Invalid versions (< 1.0) return a version of 0
* - Versions > known return a version one higher than we know of
* to accomodate a theoretically newer version */
SSL3ProtocolVersion
dtls_DTLSVersionToTLSVersion(SSL3ProtocolVersion dtlsv)
{
if (MSB(dtlsv) == 0xff) {
return 0;
}
if (dtlsv == SSL_LIBRARY_VERSION_DTLS_1_0_WIRE) {
return SSL_LIBRARY_VERSION_TLS_1_1;
}
/* Handle the skipped version of DTLS 1.1 by returning
* an error. */
if (dtlsv == ((~0x0101) & 0xffff)) {
return 0;
}
if (dtlsv == SSL_LIBRARY_VERSION_DTLS_1_2_WIRE) {
return SSL_LIBRARY_VERSION_TLS_1_2;
}
if (dtlsv == SSL_LIBRARY_VERSION_DTLS_1_3_WIRE) {
return SSL_LIBRARY_VERSION_TLS_1_3;
}
/* Return a fictional higher version than we know of */
return SSL_LIBRARY_VERSION_MAX_SUPPORTED + 1;
}
/* On this socket, Disable non-DTLS cipher suites in the argument's list */
SECStatus
ssl3_DisableNonDTLSSuites(sslSocket *ss)
{
const ssl3CipherSuite *suite;
for (suite = nonDTLSSuites; *suite; ++suite) {
PORT_CheckSuccess(ssl3_CipherPrefSet(ss, *suite, PR_FALSE));
}
return SECSuccess;
}
/* Allocate a DTLSQueuedMessage.
*
* Called from dtls_QueueMessage()
*/
static DTLSQueuedMessage *
dtls_AllocQueuedMessage(ssl3CipherSpec *cwSpec, SSLContentType ct,
const unsigned char *data, PRUint32 len)
{
DTLSQueuedMessage *msg;
msg = PORT_ZNew(DTLSQueuedMessage);
if (!msg)
return NULL;
msg->data = PORT_Alloc(len);
if (!msg->data) {
PORT_Free(msg);
return NULL;
}
PORT_Memcpy(msg->data, data, len);
msg->len = len;
msg->cwSpec = cwSpec;
msg->type = ct;
/* Safe if we are < 1.3, since the refct is
* already very high. */
ssl_CipherSpecAddRef(cwSpec);
return msg;
}
/*
* Free a handshake message
*
* Called from dtls_FreeHandshakeMessages()
*/
void
dtls_FreeHandshakeMessage(DTLSQueuedMessage *msg)
{
if (!msg)
return;
/* Safe if we are < 1.3, since the refct is
* already very high. */
ssl_CipherSpecRelease(msg->cwSpec);
PORT_ZFree(msg->data, msg->len);
PORT_Free(msg);
}
/*
* Free a list of handshake messages
*
* Called from:
* dtls_HandleHandshake()
* ssl3_DestroySSL3Info()
*/
void
dtls_FreeHandshakeMessages(PRCList *list)
{
PRCList *cur_p;
while (!PR_CLIST_IS_EMPTY(list)) {
cur_p = PR_LIST_TAIL(list);
PR_REMOVE_LINK(cur_p);
dtls_FreeHandshakeMessage((DTLSQueuedMessage *)cur_p);
}
}
/* Called by dtls_HandleHandshake() and dtls_MaybeRetransmitHandshake() if a
* handshake message retransmission is detected. */
static SECStatus
dtls_RetransmitDetected(sslSocket *ss)
{
dtlsTimer *timer = ss->ssl3.hs.rtTimer;
SECStatus rv = SECSuccess;
PORT_Assert(ss->opt.noLocks || ssl_HaveRecvBufLock(ss));
PORT_Assert(ss->opt.noLocks || ssl_HaveSSL3HandshakeLock(ss));
if (timer->cb == dtls_RetransmitTimerExpiredCb) {
/* Check to see if we retransmitted recently. If so,
* suppress the triggered retransmit. This avoids
* retransmit wars after packet loss.
* This is not in RFC 5346 but it should be.
*/
if ((PR_IntervalNow() - timer->started) >
(timer->timeout / 4)) {
SSL_TRC(30,
("%d: SSL3[%d]: Shortcutting retransmit timer",
SSL_GETPID(), ss->fd));
/* Cancel the timer and call the CB,
* which re-arms the timer */
dtls_CancelTimer(ss, ss->ssl3.hs.rtTimer);
dtls_RetransmitTimerExpiredCb(ss);
} else {
SSL_TRC(30,
("%d: SSL3[%d]: Ignoring retransmission: "
"last retransmission %dms ago, suppressed for %dms",
SSL_GETPID(), ss->fd,
PR_IntervalNow() - timer->started,
timer->timeout / 4));
}
} else if (timer->cb == dtls_FinishedTimerCb) {
SSL_TRC(30, ("%d: SSL3[%d]: Retransmit detected in holddown",
SSL_GETPID(), ss->fd));
/* Retransmit the messages and re-arm the timer
* Note that we are not backing off the timer here.
* The spec isn't clear and my reasoning is that this
* may be a re-ordered packet rather than slowness,
* so let's be aggressive. */
dtls_CancelTimer(ss, ss->ssl3.hs.rtTimer);
rv = dtls_TransmitMessageFlight(ss);
if (rv == SECSuccess) {
rv = dtls_StartHolddownTimer(ss);
}
} else {
PORT_Assert(timer->cb == NULL);
/* ... and ignore it. */
}
return rv;
}
static SECStatus
dtls_HandleHandshakeMessage(sslSocket *ss, PRUint8 *data, PRBool last)
{
ss->ssl3.hs.recvdHighWater = -1;
return ssl3_HandleHandshakeMessage(ss, data, ss->ssl3.hs.msg_len,
last);
}
/* Called only from ssl3_HandleRecord, for each (deciphered) DTLS record.
* origBuf is the decrypted ssl record content and is expected to contain
* complete handshake records
* Caller must hold the handshake and RecvBuf locks.
*
* Note that this code uses msg_len for two purposes:
*
* (1) To pass the length to ssl3_HandleHandshakeMessage()
* (2) To carry the length of a message currently being reassembled
*
* However, unlike ssl3_HandleHandshake(), it is not used to carry
* the state of reassembly (i.e., whether one is in progress). That
* is carried in recvdHighWater and recvdFragments.
*/
#define OFFSET_BYTE(o) (o / 8)
#define OFFSET_MASK(o) (1 << (o % 8))
SECStatus
dtls_HandleHandshake(sslSocket *ss, DTLSEpoch epoch, sslSequenceNumber seqNum,
sslBuffer *origBuf)
{
sslBuffer buf = *origBuf;
SECStatus rv = SECSuccess;
PRBool discarded = PR_FALSE;
ss->ssl3.hs.endOfFlight = PR_FALSE;
PORT_Assert(ss->opt.noLocks || ssl_HaveRecvBufLock(ss));
PORT_Assert(ss->opt.noLocks || ssl_HaveSSL3HandshakeLock(ss));
while (buf.len > 0) {
PRUint8 type;
PRUint32 message_length;
PRUint16 message_seq;
PRUint32 fragment_offset;
PRUint32 fragment_length;
PRUint32 offset;
if (buf.len < 12) {
PORT_SetError(SSL_ERROR_RX_MALFORMED_HANDSHAKE);
rv = SECFailure;
goto loser;
}
/* Parse the header */
type = buf.buf[0];
message_length = (buf.buf[1] << 16) | (buf.buf[2] << 8) | buf.buf[3];
message_seq = (buf.buf[4] << 8) | buf.buf[5];
fragment_offset = (buf.buf[6] << 16) | (buf.buf[7] << 8) | buf.buf[8];
fragment_length = (buf.buf[9] << 16) | (buf.buf[10] << 8) | buf.buf[11];
#define MAX_HANDSHAKE_MSG_LEN 0x1ffff /* 128k - 1 */
if (message_length > MAX_HANDSHAKE_MSG_LEN) {
(void)ssl3_DecodeError(ss);
PORT_SetError(SSL_ERROR_RX_MALFORMED_HANDSHAKE);
rv = SECFailure;
goto loser;
}
#undef MAX_HANDSHAKE_MSG_LEN
buf.buf += 12;
buf.len -= 12;
/* This fragment must be complete */
if (buf.len < fragment_length) {
PORT_SetError(SSL_ERROR_RX_MALFORMED_HANDSHAKE);
rv = SECFailure;
goto loser;
}
/* Sanity check the packet contents */
if ((fragment_length + fragment_offset) > message_length) {
PORT_SetError(SSL_ERROR_RX_MALFORMED_HANDSHAKE);
rv = SECFailure;
goto loser;
}
/* If we're a server and we receive what appears to be a retried
* ClientHello, and we are expecting a ClientHello, move the receive
* sequence number forward. This allows for a retried ClientHello if we
* send a stateless HelloRetryRequest. */
if (message_seq > ss->ssl3.hs.recvMessageSeq &&
message_seq == 1 &&
fragment_offset == 0 &&
ss->ssl3.hs.ws == wait_client_hello &&
(SSLHandshakeType)type == ssl_hs_client_hello) {
SSL_TRC(5, ("%d: DTLS[%d]: Received apparent 2nd ClientHello",
SSL_GETPID(), ss->fd));
ss->ssl3.hs.recvMessageSeq = 1;
ss->ssl3.hs.helloRetry = PR_TRUE;
}
/* There are three ways we could not be ready for this packet.
*
* 1. It's a partial next message.
* 2. It's a partial or complete message beyond the next
* 3. It's a message we've already seen
*
* If it's the complete next message we accept it right away.
* This is the common case for short messages
*/
if ((message_seq == ss->ssl3.hs.recvMessageSeq) &&
(fragment_offset == 0) &&
(fragment_length == message_length)) {
/* Complete next message. Process immediately */
ss->ssl3.hs.msg_type = (SSLHandshakeType)type;
ss->ssl3.hs.msg_len = message_length;
rv = dtls_HandleHandshakeMessage(ss, buf.buf,
buf.len == fragment_length);
if (rv == SECFailure) {
goto loser;
}
} else {
if (message_seq < ss->ssl3.hs.recvMessageSeq) {
/* Case 3: we do an immediate retransmit if we're
* in a waiting state. */
rv = dtls_RetransmitDetected(ss);
goto loser;
} else if (message_seq > ss->ssl3.hs.recvMessageSeq) {
/* Case 2
*
* Ignore this message. This means we don't handle out of
* order complete messages that well, but we're still
* compliant and this probably does not happen often
*
* XXX OK for now. Maybe do something smarter at some point?
*/
SSL_TRC(10, ("%d: SSL3[%d]: dtls_HandleHandshake, discarding handshake message",
SSL_GETPID(), ss->fd));
discarded = PR_TRUE;
} else {
PRInt32 end = fragment_offset + fragment_length;
/* Case 1
*
* Buffer the fragment for reassembly
*/
/* Make room for the message */
if (ss->ssl3.hs.recvdHighWater == -1) {
PRUint32 map_length = OFFSET_BYTE(message_length) + 1;
rv = sslBuffer_Grow(&ss->ssl3.hs.msg_body, message_length);
if (rv != SECSuccess)
goto loser;
/* Make room for the fragment map */
rv = sslBuffer_Grow(&ss->ssl3.hs.recvdFragments,
map_length);
if (rv != SECSuccess)
goto loser;
/* Reset the reassembly map */
ss->ssl3.hs.recvdHighWater = 0;
PORT_Memset(ss->ssl3.hs.recvdFragments.buf, 0,
ss->ssl3.hs.recvdFragments.space);
ss->ssl3.hs.msg_type = (SSLHandshakeType)type;
ss->ssl3.hs.msg_len = message_length;
}
/* If we have a message length mismatch, abandon the reassembly
* in progress and hope that the next retransmit will give us
* something sane
*/
if (message_length != ss->ssl3.hs.msg_len) {
ss->ssl3.hs.recvdHighWater = -1;
PORT_SetError(SSL_ERROR_RX_MALFORMED_HANDSHAKE);
rv = SECFailure;
goto loser;
}
/* Now copy this fragment into the buffer. */
if (end > ss->ssl3.hs.recvdHighWater) {
PORT_Memcpy(ss->ssl3.hs.msg_body.buf + fragment_offset,
buf.buf, fragment_length);
}
/* This logic is a bit tricky. We have two values for
* reassembly state:
*
* - recvdHighWater contains the highest contiguous number of
* bytes received
* - recvdFragments contains a bitmask of packets received
* above recvdHighWater
*
* This avoids having to fill in the bitmask in the common
* case of adjacent fragments received in sequence
*/
if (fragment_offset <= (unsigned int)ss->ssl3.hs.recvdHighWater) {
/* Either this is the adjacent fragment or an overlapping
* fragment */
if (end > ss->ssl3.hs.recvdHighWater) {
ss->ssl3.hs.recvdHighWater = end;
}
} else {
for (offset = fragment_offset; offset < end; offset++) {
ss->ssl3.hs.recvdFragments.buf[OFFSET_BYTE(offset)] |=
OFFSET_MASK(offset);
}
}
/* Now figure out the new high water mark if appropriate */
for (offset = ss->ssl3.hs.recvdHighWater;
offset < ss->ssl3.hs.msg_len; offset++) {
/* Note that this loop is not efficient, since it counts
* bit by bit. If we have a lot of out-of-order packets,
* we should optimize this */
if (ss->ssl3.hs.recvdFragments.buf[OFFSET_BYTE(offset)] &
OFFSET_MASK(offset)) {
ss->ssl3.hs.recvdHighWater++;
} else {
break;
}
}
/* If we have all the bytes, then we are good to go */
if (ss->ssl3.hs.recvdHighWater == ss->ssl3.hs.msg_len) {
rv = dtls_HandleHandshakeMessage(ss, ss->ssl3.hs.msg_body.buf,
buf.len == fragment_length);
if (rv == SECFailure) {
goto loser;
}
}
}
}
buf.buf += fragment_length;
buf.len -= fragment_length;
}
// This should never happen, but belt and suspenders.
if (rv != SECSuccess) {
PORT_Assert(0);
goto loser;
}
/* If we processed all the fragments in this message, then mark it as remembered.
* TODO(ekr@rtfm.com): Store out of order messages for DTLS 1.3 so ACKs work
* better. Bug 1392620.*/
if (!discarded && tls13_MaybeTls13(ss)) {
rv = dtls13_RememberFragment(ss, &ss->ssl3.hs.dtlsRcvdHandshake,
0, 0, 0, epoch, seqNum);
}
if (rv != SECSuccess) {
goto loser;
}
rv = dtls13_SetupAcks(ss);
loser:
origBuf->len = 0; /* So ssl3_GatherAppDataRecord will keep looping. */
return rv;
}
/* Enqueue a message (either handshake or CCS)
*
* Called from:
* dtls_StageHandshakeMessage()
* ssl3_SendChangeCipherSpecs()
*/
SECStatus
dtls_QueueMessage(sslSocket *ss, SSLContentType ct,
const PRUint8 *pIn, PRInt32 nIn)
{
SECStatus rv = SECSuccess;
DTLSQueuedMessage *msg = NULL;
ssl3CipherSpec *spec;
PORT_Assert(ss->opt.noLocks || ssl_HaveSSL3HandshakeLock(ss));
PORT_Assert(ss->opt.noLocks || ssl_HaveXmitBufLock(ss));
spec = ss->ssl3.cwSpec;
msg = dtls_AllocQueuedMessage(spec, ct, pIn, nIn);
if (!msg) {
PORT_SetError(SEC_ERROR_NO_MEMORY);
rv = SECFailure;
} else {
PR_APPEND_LINK(&msg->link, &ss->ssl3.hs.lastMessageFlight);
}
return rv;
}
/* Add DTLS handshake message to the pending queue
* Empty the sendBuf buffer.
* Always set sendBuf.len to 0, even when returning SECFailure.
*
* Called from:
* ssl3_AppendHandshakeHeader()
* dtls_FlushHandshake()
*/
SECStatus
dtls_StageHandshakeMessage(sslSocket *ss)
{
SECStatus rv = SECSuccess;
PORT_Assert(ss->opt.noLocks || ssl_HaveSSL3HandshakeLock(ss));
PORT_Assert(ss->opt.noLocks || ssl_HaveXmitBufLock(ss));
/* This function is sometimes called when no data is actually to
* be staged, so just return SECSuccess. */
if (!ss->sec.ci.sendBuf.buf || !ss->sec.ci.sendBuf.len)
return rv;
rv = dtls_QueueMessage(ss, ssl_ct_handshake,
ss->sec.ci.sendBuf.buf, ss->sec.ci.sendBuf.len);
/* Whether we succeeded or failed, toss the old handshake data. */
ss->sec.ci.sendBuf.len = 0;
return rv;
}
/* Enqueue the handshake message in sendBuf (if any) and then
* transmit the resulting flight of handshake messages.
*
* Called from:
* ssl3_FlushHandshake()
*/
SECStatus
dtls_FlushHandshakeMessages(sslSocket *ss, PRInt32 flags)
{
SECStatus rv = SECSuccess;
PORT_Assert(ss->opt.noLocks || ssl_HaveSSL3HandshakeLock(ss));
PORT_Assert(ss->opt.noLocks || ssl_HaveXmitBufLock(ss));
rv = dtls_StageHandshakeMessage(ss);
if (rv != SECSuccess)
return rv;
if (!(flags & ssl_SEND_FLAG_FORCE_INTO_BUFFER)) {
rv = dtls_TransmitMessageFlight(ss);
if (rv != SECSuccess) {
return rv;
}
if (!(flags & ssl_SEND_FLAG_NO_RETRANSMIT)) {
rv = dtls_StartRetransmitTimer(ss);
} else {
PORT_Assert(ss->version < SSL_LIBRARY_VERSION_TLS_1_3);
}
}
return rv;
}
/* The callback for when the retransmit timer expires
*
* Called from:
* dtls_CheckTimer()
* dtls_HandleHandshake()
*/
static void
dtls_RetransmitTimerExpiredCb(sslSocket *ss)
{
SECStatus rv;
dtlsTimer *timer = ss->ssl3.hs.rtTimer;
ss->ssl3.hs.rtRetries++;
if (!(ss->ssl3.hs.rtRetries % 3)) {
/* If one of the messages was potentially greater than > MTU,
* then downgrade. Do this every time we have retransmitted a
* message twice, per RFC 6347 Sec. 4.1.1 */
dtls_SetMTU(ss, ss->ssl3.hs.maxMessageSent - 1);
}
rv = dtls_TransmitMessageFlight(ss);
if (rv == SECSuccess) {
/* Re-arm the timer */
timer->timeout *= 2;
if (timer->timeout > DTLS_RETRANSMIT_MAX_MS) {
timer->timeout = DTLS_RETRANSMIT_MAX_MS;
}
timer->started = PR_IntervalNow();
timer->cb = dtls_RetransmitTimerExpiredCb;
SSL_TRC(30,
("%d: SSL3[%d]: Retransmit #%d, next in %d",
SSL_GETPID(), ss->fd,
ss->ssl3.hs.rtRetries, timer->timeout));
}
/* else: OK for now. In future maybe signal the stack that we couldn't
* transmit. For now, let the read handle any real network errors */
}
#define DTLS_HS_HDR_LEN 12
#define DTLS_MIN_FRAGMENT (DTLS_HS_HDR_LEN + 1 + DTLS_MAX_EXPANSION)
/* Encrypt and encode a handshake message fragment. Flush the data out to the
* network if there is insufficient space for any fragment. */
static SECStatus
dtls_SendFragment(sslSocket *ss, DTLSQueuedMessage *msg, PRUint8 *data,
unsigned int len)
{
PRInt32 sent;
SECStatus rv;
PRINT_BUF(40, (ss, "dtls_SendFragment", data, len));
sent = ssl3_SendRecord(ss, msg->cwSpec, msg->type, data, len,
ssl_SEND_FLAG_FORCE_INTO_BUFFER);
if (sent != len) {
if (sent != -1) {
PORT_SetError(SEC_ERROR_LIBRARY_FAILURE);
}
return SECFailure;
}
/* If another fragment won't fit, flush. */
if (ss->ssl3.mtu < ss->pendingBuf.len + DTLS_MIN_FRAGMENT) {
SSL_TRC(20, ("%d: DTLS[%d]: dtls_SendFragment: flush",
SSL_GETPID(), ss->fd));
rv = dtls_SendSavedWriteData(ss);
if (rv != SECSuccess) {
return SECFailure;
}
}
return SECSuccess;
}
/* Fragment a handshake message into multiple records and send them. */
static SECStatus
dtls_FragmentHandshake(sslSocket *ss, DTLSQueuedMessage *msg)
{
PRBool fragmentWritten = PR_FALSE;
PRUint16 msgSeq;
PRUint8 *fragment;
PRUint32 fragmentOffset = 0;
PRUint32 fragmentLen;
const PRUint8 *content = msg->data + DTLS_HS_HDR_LEN;
PRUint32 contentLen = msg->len - DTLS_HS_HDR_LEN;
SECStatus rv;
/* The headers consume 12 bytes so the smallest possible message (i.e., an
* empty one) is 12 bytes. */
PORT_Assert(msg->len >= DTLS_HS_HDR_LEN);
/* DTLS only supports fragmenting handshaking messages. */
PORT_Assert(msg->type == ssl_ct_handshake);
msgSeq = (msg->data[4] << 8) | msg->data[5];
/* do {} while() so that empty messages are sent at least once. */
do {
PRUint8 buf[DTLS_MAX_MTU]; /* >= than largest plausible MTU */
PRBool hasUnackedRange;
PRUint32 end;
hasUnackedRange = dtls_NextUnackedRange(ss, msgSeq,
fragmentOffset, contentLen,
&fragmentOffset, &end);
if (!hasUnackedRange) {
SSL_TRC(20, ("%d: SSL3[%d]: FragmentHandshake %d: all acknowledged",
SSL_GETPID(), ss->fd, msgSeq));
break;
}
SSL_TRC(20, ("%d: SSL3[%d]: FragmentHandshake %d: unacked=%u-%u",
SSL_GETPID(), ss->fd, msgSeq, fragmentOffset, end));
/* Cut down to the data we have available. */
PORT_Assert(fragmentOffset <= contentLen);
PORT_Assert(fragmentOffset <= end);
PORT_Assert(end <= contentLen);
fragmentLen = PR_MIN(end, contentLen) - fragmentOffset;
/* Limit further by the record size limit. Account for the header. */
fragmentLen = PR_MIN(fragmentLen,
msg->cwSpec->recordSizeLimit - DTLS_HS_HDR_LEN);
/* Reduce to the space remaining in the MTU. */
fragmentLen = PR_MIN(fragmentLen,
ss->ssl3.mtu - /* MTU estimate. */
ss->pendingBuf.len - /* Less any unsent records. */
DTLS_MAX_EXPANSION - /* Allow for expansion. */
DTLS_HS_HDR_LEN); /* And the handshake header. */
PORT_Assert(fragmentLen > 0 || fragmentOffset == 0);
/* Make totally sure that we will fit in the buffer. This should be
* impossible; DTLS_MAX_MTU should always be more than ss->ssl3.mtu. */
if (fragmentLen >= (DTLS_MAX_MTU - DTLS_HS_HDR_LEN)) {
PORT_Assert(0);
PORT_SetError(SEC_ERROR_LIBRARY_FAILURE);
return SECFailure;
}
if (fragmentLen == contentLen) {
fragment = msg->data;
} else {
sslBuffer tmp = SSL_BUFFER_FIXED(buf, sizeof(buf));
/* Construct an appropriate-sized fragment */
/* Type, length, sequence */
rv = sslBuffer_Append(&tmp, msg->data, 6);
if (rv != SECSuccess) {
return SECFailure;
}
/* Offset. */
rv = sslBuffer_AppendNumber(&tmp, fragmentOffset, 3);
if (rv != SECSuccess) {
return SECFailure;
}
/* Length. */
rv = sslBuffer_AppendNumber(&tmp, fragmentLen, 3);
if (rv != SECSuccess) {
return SECFailure;
}
/* Data. */
rv = sslBuffer_Append(&tmp, content + fragmentOffset, fragmentLen);
if (rv != SECSuccess) {
return SECFailure;
}
fragment = SSL_BUFFER_BASE(&tmp);
}
/* Record that we are sending first, because encrypting
* increments the sequence number. */
rv = dtls13_RememberFragment(ss, &ss->ssl3.hs.dtlsSentHandshake,
msgSeq, fragmentOffset, fragmentLen,
msg->cwSpec->epoch,
msg->cwSpec->nextSeqNum);
if (rv != SECSuccess) {
return SECFailure;
}
rv = dtls_SendFragment(ss, msg, fragment,
fragmentLen + DTLS_HS_HDR_LEN);
if (rv != SECSuccess) {
return SECFailure;
}
fragmentWritten = PR_TRUE;
fragmentOffset += fragmentLen;
} while (fragmentOffset < contentLen);
if (!fragmentWritten) {
/* Nothing was written if we got here, so the whole message must have
* been acknowledged. Discard it. */
SSL_TRC(10, ("%d: SSL3[%d]: FragmentHandshake %d: removed",
SSL_GETPID(), ss->fd, msgSeq));
PR_REMOVE_LINK(&msg->link);
dtls_FreeHandshakeMessage(msg);
}
return SECSuccess;
}
/* Transmit a flight of handshake messages, stuffing them
* into as few records as seems reasonable.
*
* TODO: Space separate UDP packets out a little.
*
* Called from:
* dtls_FlushHandshake()
* dtls_RetransmitTimerExpiredCb()
*/
SECStatus
dtls_TransmitMessageFlight(sslSocket *ss)
{
SECStatus rv = SECSuccess;
PRCList *msg_p;
SSL_TRC(10, ("%d: SSL3[%d]: dtls_TransmitMessageFlight",
SSL_GETPID(), ss->fd));
ssl_GetXmitBufLock(ss);
ssl_GetSpecReadLock(ss);
/* DTLS does not buffer its handshake messages in ss->pendingBuf, but rather
* in the lastMessageFlight structure. This is just a sanity check that some
* programming error hasn't inadvertantly stuffed something in
* ss->pendingBuf. This function uses ss->pendingBuf temporarily and it
* needs to be empty to start.
*/
PORT_Assert(!ss->pendingBuf.len);
for (msg_p = PR_LIST_HEAD(&ss->ssl3.hs.lastMessageFlight);
msg_p != &ss->ssl3.hs.lastMessageFlight;) {
DTLSQueuedMessage *msg = (DTLSQueuedMessage *)msg_p;
/* Move the pointer forward so that the functions below are free to
* remove messages from the list. */
msg_p = PR_NEXT_LINK(msg_p);
/* Note: This function fragments messages so that each record is close
* to full. This produces fewer records, but it means that messages can
* be quite fragmented. Adding an extra flush here would push new
* messages into new records and reduce fragmentation. */
if (msg->type == ssl_ct_handshake) {
rv = dtls_FragmentHandshake(ss, msg);
} else {
PORT_Assert(!tls13_MaybeTls13(ss));
rv = dtls_SendFragment(ss, msg, msg->data, msg->len);
}
if (rv != SECSuccess) {
break;
}
}
/* Finally, flush any data that wasn't flushed already. */
if (rv == SECSuccess) {
rv = dtls_SendSavedWriteData(ss);
}
/* Give up the locks */
ssl_ReleaseSpecReadLock(ss);
ssl_ReleaseXmitBufLock(ss);
return rv;
}
/* Flush the data in the pendingBuf and update the max message sent
* so we can adjust the MTU estimate if we need to.
* Wrapper for ssl_SendSavedWriteData.
*
* Called from dtls_TransmitMessageFlight()
*/
static SECStatus
dtls_SendSavedWriteData(sslSocket *ss)
{
PRInt32 sent;
sent = ssl_SendSavedWriteData(ss);
if (sent < 0)
return SECFailure;
/* We should always have complete writes b/c datagram sockets
* don't really block */
if (ss->pendingBuf.len > 0) {
ssl_MapLowLevelError(SSL_ERROR_SOCKET_WRITE_FAILURE);
return SECFailure;
}
/* Update the largest message sent so we can adjust the MTU
* estimate if necessary */
if (sent > ss->ssl3.hs.maxMessageSent)
ss->ssl3.hs.maxMessageSent = sent;
return SECSuccess;
}
void
dtls_InitTimers(sslSocket *ss)
{
unsigned int i;
dtlsTimer **timers[PR_ARRAY_SIZE(ss->ssl3.hs.timers)] = {
&ss->ssl3.hs.rtTimer,
&ss->ssl3.hs.ackTimer,
&ss->ssl3.hs.hdTimer
};
static const char *timerLabels[] = {
"retransmit", "ack", "holddown"
};
PORT_Assert(PR_ARRAY_SIZE(timers) == PR_ARRAY_SIZE(timerLabels));
for (i = 0; i < PR_ARRAY_SIZE(ss->ssl3.hs.timers); ++i) {
*timers[i] = &ss->ssl3.hs.timers[i];
ss->ssl3.hs.timers[i].label = timerLabels[i];
}
}
SECStatus
dtls_StartTimer(sslSocket *ss, dtlsTimer *timer, PRUint32 time, DTLSTimerCb cb)
{
PORT_Assert(timer->cb == NULL);
SSL_TRC(10, ("%d: SSL3[%d]: %s dtls_StartTimer %s timeout=%d",
SSL_GETPID(), ss->fd, SSL_ROLE(ss), timer->label, time));
timer->started = PR_IntervalNow();
timer->timeout = time;
timer->cb = cb;
return SECSuccess;
}
SECStatus
dtls_RestartTimer(sslSocket *ss, dtlsTimer *timer)
{
timer->started = PR_IntervalNow();
return SECSuccess;
}
PRBool
dtls_TimerActive(sslSocket *ss, dtlsTimer *timer)
{
return timer->cb != NULL;
}
/* Start a timer for retransmission. */
static SECStatus
dtls_StartRetransmitTimer(sslSocket *ss)
{
ss->ssl3.hs.rtRetries = 0;
return dtls_StartTimer(ss, ss->ssl3.hs.rtTimer,
DTLS_RETRANSMIT_INITIAL_MS,
dtls_RetransmitTimerExpiredCb);
}
/* Start a timer for holding an old cipher spec. */
SECStatus
dtls_StartHolddownTimer(sslSocket *ss)
{
ss->ssl3.hs.rtRetries = 0;
return dtls_StartTimer(ss, ss->ssl3.hs.rtTimer,
DTLS_RETRANSMIT_FINISHED_MS,
dtls_FinishedTimerCb);
}
/* Cancel a pending timer
*
* Called from:
* dtls_HandleHandshake()
* dtls_CheckTimer()
*/
void
dtls_CancelTimer(sslSocket *ss, dtlsTimer *timer)
{
SSL_TRC(30, ("%d: SSL3[%d]: %s dtls_CancelTimer %s",
SSL_GETPID(), ss->fd, SSL_ROLE(ss),
timer->label));
PORT_Assert(ss->opt.noLocks || ssl_HaveRecvBufLock(ss));
timer->cb = NULL;
}
static void
dtls_CancelAllTimers(sslSocket *ss)
{
unsigned int i;
for (i = 0; i < PR_ARRAY_SIZE(ss->ssl3.hs.timers); ++i) {
dtls_CancelTimer(ss, &ss->ssl3.hs.timers[i]);
}
}
/* Check the pending timer and fire the callback if it expired
*
* Called from ssl3_GatherCompleteHandshake()
*/
void
dtls_CheckTimer(sslSocket *ss)
{
unsigned int i;
SSL_TRC(30, ("%d: SSL3[%d]: dtls_CheckTimer (%s)",
SSL_GETPID(), ss->fd, ss->sec.isServer ? "server" : "client"));
ssl_GetSSL3HandshakeLock(ss);
for (i = 0; i < PR_ARRAY_SIZE(ss->ssl3.hs.timers); ++i) {
dtlsTimer *timer = &ss->ssl3.hs.timers[i];
if (!timer->cb) {
continue;
}
if ((PR_IntervalNow() - timer->started) >=
PR_MillisecondsToInterval(timer->timeout)) {
/* Timer has expired */
DTLSTimerCb cb = timer->cb;
SSL_TRC(10, ("%d: SSL3[%d]: %s firing timer %s",
SSL_GETPID(), ss->fd, SSL_ROLE(ss),
timer->label));
/* Cancel the timer so that we can call the CB safely */
dtls_CancelTimer(ss, timer);
/* Now call the CB */
cb(ss);
}
}
ssl_ReleaseSSL3HandshakeLock(ss);
}
/* The callback to fire when the holddown timer for the Finished
* message expires and we can delete it
*
* Called from dtls_CheckTimer()
*/
static void
dtls_FinishedTimerCb(sslSocket *ss)
{
dtls_FreeHandshakeMessages(&ss->ssl3.hs.lastMessageFlight);
}
/* Cancel the Finished hold-down timer and destroy the
* pending cipher spec. Note that this means that
* successive rehandshakes will fail if the Finished is
* lost.
*
* XXX OK for now. Figure out how to handle the combination
* of Finished lost and rehandshake
*/
void
dtls_RehandshakeCleanup(sslSocket *ss)
{
/* Skip this if we are handling a second ClientHello. */
if (ss->ssl3.hs.helloRetry) {
return;
}
PORT_Assert((ss->version < SSL_LIBRARY_VERSION_TLS_1_3));
dtls_CancelAllTimers(ss);
dtls_FreeHandshakeMessages(&ss->ssl3.hs.lastMessageFlight);
ss->ssl3.hs.sendMessageSeq = 0;
ss->ssl3.hs.recvMessageSeq = 0;
}
/* Set the MTU to the next step less than or equal to the
* advertised value. Also used to downgrade the MTU by
* doing dtls_SetMTU(ss, biggest packet set).
*
* Passing 0 means set this to the largest MTU known
* (effectively resetting the PMTU backoff value).
*
* Called by:
* ssl3_InitState()
* dtls_RetransmitTimerExpiredCb()
*/
void
dtls_SetMTU(sslSocket *ss, PRUint16 advertised)
{
int i;
if (advertised == 0) {
ss->ssl3.mtu = COMMON_MTU_VALUES[0];
SSL_TRC(30, ("Resetting MTU to %d", ss->ssl3.mtu));
return;
}
for (i = 0; i < PR_ARRAY_SIZE(COMMON_MTU_VALUES); i++) {
if (COMMON_MTU_VALUES[i] <= advertised) {
ss->ssl3.mtu = COMMON_MTU_VALUES[i];
SSL_TRC(30, ("Resetting MTU to %d", ss->ssl3.mtu));
return;
}
}
/* Fallback */
ss->ssl3.mtu = COMMON_MTU_VALUES[PR_ARRAY_SIZE(COMMON_MTU_VALUES) - 1];
SSL_TRC(30, ("Resetting MTU to %d", ss->ssl3.mtu));
}
/* Called from ssl3_HandleHandshakeMessage() when it has deciphered a
* DTLS hello_verify_request
* Caller must hold Handshake and RecvBuf locks.
*/
SECStatus
dtls_HandleHelloVerifyRequest(sslSocket *ss, PRUint8 *b, PRUint32 length)
{
int errCode = SSL_ERROR_RX_MALFORMED_HELLO_VERIFY_REQUEST;
SECStatus rv;
SSL3ProtocolVersion temp;
SSL3AlertDescription desc = illegal_parameter;
SSL_TRC(3, ("%d: SSL3[%d]: handle hello_verify_request handshake",
SSL_GETPID(), ss->fd));
PORT_Assert(ss->opt.noLocks || ssl_HaveRecvBufLock(ss));
PORT_Assert(ss->opt.noLocks || ssl_HaveSSL3HandshakeLock(ss));
if (ss->ssl3.hs.ws != wait_server_hello) {
errCode = SSL_ERROR_RX_UNEXPECTED_HELLO_VERIFY_REQUEST;
desc = unexpected_message;
goto alert_loser;
}
dtls_ReceivedFirstMessageInFlight(ss);
/* The version.
*
* RFC 4347 required that you verify that the server versions
* match (Section 4.2.1) in the HelloVerifyRequest and the
* ServerHello.
*
* RFC 6347 suggests (SHOULD) that servers always use 1.0 in
* HelloVerifyRequest and allows the versions not to match,
* especially when 1.2 is being negotiated.
*
* Therefore we do not do anything to enforce a match, just
* read and check that this value is sane.
*/
rv = ssl_ClientReadVersion(ss, &b, &length, &temp);
if (rv != SECSuccess) {
goto loser; /* alert has been sent */
}
/* Read the cookie.
* IMPORTANT: The value of ss->ssl3.hs.cookie is only valid while the
* HelloVerifyRequest message remains valid. */
rv = ssl3_ConsumeHandshakeVariable(ss, &ss->ssl3.hs.cookie, 1, &b, &length);
if (rv != SECSuccess) {
goto loser; /* alert has been sent */
}
if (ss->ssl3.hs.cookie.len > DTLS_COOKIE_BYTES) {
desc = decode_error;
goto alert_loser; /* malformed. */
}
ssl_GetXmitBufLock(ss); /*******************************/
/* Now re-send the client hello */
rv = ssl3_SendClientHello(ss, client_hello_retransmit);
ssl_ReleaseXmitBufLock(ss); /*******************************/
if (rv == SECSuccess)
return rv;
alert_loser:
(void)SSL3_SendAlert(ss, alert_fatal, desc);
loser:
ssl_MapLowLevelError(errCode);
return SECFailure;
}
/* Initialize the DTLS anti-replay window
*
* Called from:
* ssl3_SetupPendingCipherSpec()
* ssl3_InitCipherSpec()
*/
void
dtls_InitRecvdRecords(DTLSRecvdRecords *records)
{
PORT_Memset(records->data, 0, sizeof(records->data));
records->left = 0;
records->right = DTLS_RECVD_RECORDS_WINDOW - 1;
}
/*
* Has this DTLS record been received? Return values are:
* -1 -- out of range to the left
* 0 -- not received yet
* 1 -- replay
*
* Called from: ssl3_HandleRecord()
*/
int
dtls_RecordGetRecvd(const DTLSRecvdRecords *records, sslSequenceNumber seq)
{
PRUint64 offset;
/* Out of range to the left */
if (seq < records->left) {
return -1;
}
/* Out of range to the right; since we advance the window on
* receipt, that means that this packet has not been received
* yet */
if (seq > records->right)
return 0;
offset = seq % DTLS_RECVD_RECORDS_WINDOW;
return !!(records->data[offset / 8] & (1 << (offset % 8)));
}
/* Update the DTLS anti-replay window
*
* Called from ssl3_HandleRecord()
*/
void
dtls_RecordSetRecvd(DTLSRecvdRecords *records, sslSequenceNumber seq)
{
PRUint64 offset;
if (seq < records->left)
return;
if (seq > records->right) {
sslSequenceNumber new_left;
sslSequenceNumber new_right;
sslSequenceNumber right;
/* Slide to the right; this is the tricky part
*
* 1. new_top is set to have room for seq, on the
* next byte boundary by setting the right 8
* bits of seq
* 2. new_left is set to compensate.
* 3. Zero all bits between top and new_top. Since
* this is a ring, this zeroes everything as-yet
* unseen. Because we always operate on byte
* boundaries, we can zero one byte at a time
*/
new_right = seq | 0x07;
new_left = (new_right - DTLS_RECVD_RECORDS_WINDOW) + 1;
if (new_right > records->right + DTLS_RECVD_RECORDS_WINDOW) {
PORT_Memset(records->data, 0, sizeof(records->data));
} else {
for (right = records->right + 8; right <= new_right; right += 8) {
offset = right % DTLS_RECVD_RECORDS_WINDOW;
records->data[offset / 8] = 0;
}
}
records->right = new_right;
records->left = new_left;
}
offset = seq % DTLS_RECVD_RECORDS_WINDOW;
records->data[offset / 8] |= (1 << (offset % 8));
}
SECStatus
DTLS_GetHandshakeTimeout(PRFileDesc *socket, PRIntervalTime *timeout)
{
sslSocket *ss = NULL;
PRBool found = PR_FALSE;
PRIntervalTime now = PR_IntervalNow();
PRIntervalTime to;
unsigned int i;
*timeout = PR_INTERVAL_NO_TIMEOUT;
ss = ssl_FindSocket(socket);
if (!ss) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
return SECFailure;
}
if (!IS_DTLS(ss)) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
return SECFailure;
}
for (i = 0; i < PR_ARRAY_SIZE(ss->ssl3.hs.timers); ++i) {
PRIntervalTime elapsed;
PRIntervalTime desired;
dtlsTimer *timer = &ss->ssl3.hs.timers[i];
if (!timer->cb) {
continue;
}
found = PR_TRUE;
elapsed = now - timer->started;
desired = PR_MillisecondsToInterval(timer->timeout);
if (elapsed > desired) {
/* Timer expired */
*timeout = PR_INTERVAL_NO_WAIT;
return SECSuccess;
} else {
to = desired - elapsed;
}
if (*timeout > to) {
*timeout = to;
}
}
if (!found) {
PORT_SetError(SSL_ERROR_NO_TIMERS_FOUND);
return SECFailure;
}
return SECSuccess;
}
PRBool
dtls_IsLongHeader(SSL3ProtocolVersion version, PRUint8 firstOctet)
{
#ifndef UNSAFE_FUZZER_MODE
return version < SSL_LIBRARY_VERSION_TLS_1_3 ||
firstOctet == ssl_ct_handshake ||
firstOctet == ssl_ct_ack ||
firstOctet == ssl_ct_alert;
#else
return PR_TRUE;
#endif
}
PRBool
dtls_IsDtls13Ciphertext(SSL3ProtocolVersion version, PRUint8 firstOctet)
{
// Allow no version in case we haven't negotiated one yet.
return (version == 0 || version >= SSL_LIBRARY_VERSION_TLS_1_3) &&
(firstOctet & 0xe0) == 0x20;
}
DTLSEpoch
dtls_ReadEpoch(const ssl3CipherSpec *crSpec, const PRUint8 *hdr)
{
DTLSEpoch epoch;
DTLSEpoch maxEpoch;
DTLSEpoch partial;
if (dtls_IsLongHeader(crSpec->version, hdr[0])) {
return ((DTLSEpoch)hdr[3] << 8) | hdr[4];
}
/* A lot of how we recover the epoch here will depend on how we plan to
* manage KeyUpdate. In the case that we decide to install a new read spec
* as a KeyUpdate is handled, crSpec will always be the highest epoch we can
* possibly receive. That makes this easier to manage.
*/
if (dtls_IsDtls13Ciphertext(crSpec->version, hdr[0])) {
/* TODO(ekr@rtfm.com: do something with the two-bit epoch. */
/* Use crSpec->epoch, or crSpec->epoch - 1 if the last bit differs. */
return crSpec->epoch - ((hdr[0] ^ crSpec->epoch) & 0x3);
}
/* dtls_GatherData should ensure that this works. */
PORT_Assert(hdr[0] == ssl_ct_application_data);
/* This uses the same method as is used to recover the sequence number in
* dtls_ReadSequenceNumber, except that the maximum value is set to the
* current epoch. */
partial = hdr[1] >> 6;
maxEpoch = PR_MAX(crSpec->epoch, 3);
epoch = (maxEpoch & 0xfffc) | partial;
if (partial > (maxEpoch & 0x03)) {
epoch -= 4;
}
return epoch;
}
static sslSequenceNumber
dtls_ReadSequenceNumber(const ssl3CipherSpec *spec, const PRUint8 *hdr)
{
sslSequenceNumber cap;
sslSequenceNumber partial;
sslSequenceNumber seqNum;
sslSequenceNumber mask;
if (dtls_IsLongHeader(spec->version, hdr[0])) {
static const unsigned int seqNumOffset = 5; /* type, version, epoch */
static const unsigned int seqNumLength = 6;
sslReader r = SSL_READER(hdr + seqNumOffset, seqNumLength);
(void)sslRead_ReadNumber(&r, seqNumLength, &seqNum);
return seqNum;
}
/* Only the least significant bits of the sequence number is available here.
* This recovers the value based on the next expected sequence number.
*
* This works by determining the maximum possible sequence number, which is
* half the range of possible values above the expected next value (the
* expected next value is in |spec->seqNum|). Then, the last part of the
* sequence number is replaced. If that causes the value to exceed the
* maximum, subtract an entire range.
*/
if (hdr[0] & 0x08) {
cap = spec->nextSeqNum + (1ULL << 15);
partial = (((sslSequenceNumber)hdr[1]) << 8) |
(sslSequenceNumber)hdr[2];
mask = (1ULL << 16) - 1;
} else {
cap = spec->nextSeqNum + (1ULL << 7);
partial = (sslSequenceNumber)hdr[1];
mask = (1ULL << 8) - 1;
}
seqNum = (cap & ~mask) | partial;
/* The second check prevents the value from underflowing if we get a large
* gap at the start of a connection, where this subtraction would cause the
* sequence number to wrap to near UINT64_MAX. */
if ((partial > (cap & mask)) && (seqNum > mask)) {
seqNum -= mask + 1;
}
return seqNum;
}
/*
* DTLS relevance checks:
* Note that this code currently ignores all out-of-epoch packets,
* which means we lose some in the case of rehandshake +
* loss/reordering. Since DTLS is explicitly unreliable, this
* seems like a good tradeoff for implementation effort and is
* consistent with the guidance of RFC 6347 Sections 4.1 and 4.2.4.1.
*
* If the packet is not relevant, this function returns PR_FALSE. If the packet
* is relevant, this function returns PR_TRUE and sets |*seqNumOut| to the
* packet sequence number (removing the epoch).
*/
PRBool
dtls_IsRelevant(sslSocket *ss, const ssl3CipherSpec *spec,
const SSL3Ciphertext *cText,
sslSequenceNumber *seqNumOut)
{
sslSequenceNumber seqNum = dtls_ReadSequenceNumber(spec, cText->hdr);
if (dtls_RecordGetRecvd(&spec->recvdRecords, seqNum) != 0) {
SSL_TRC(10, ("%d: SSL3[%d]: dtls_IsRelevant, rejecting "
"potentially replayed packet",
SSL_GETPID(), ss->fd));
return PR_FALSE;
}
*seqNumOut = seqNum;
return PR_TRUE;
}
void
dtls_ReceivedFirstMessageInFlight(sslSocket *ss)
{
if (!IS_DTLS(ss))
return;
/* At this point we are advancing our state machine, so we can free our last
* flight of messages. */
if (ss->ssl3.hs.ws != idle_handshake ||
ss->version >= SSL_LIBRARY_VERSION_TLS_1_3) {
/* We need to keep our last flight around in DTLS 1.2 and below,
* so we can retransmit it in response to other people's
* retransmits. */
dtls_FreeHandshakeMessages(&ss->ssl3.hs.lastMessageFlight);
/* Reset the timer to the initial value if the retry counter
* is 0, per RFC 6347, Sec. 4.2.4.1 */
dtls_CancelTimer(ss, ss->ssl3.hs.rtTimer);
if (ss->ssl3.hs.rtRetries == 0) {
ss->ssl3.hs.rtTimer->timeout = DTLS_RETRANSMIT_INITIAL_MS;
}
}
/* Empty the ACK queue (TLS 1.3 only). */
ssl_ClearPRCList(&ss->ssl3.hs.dtlsRcvdHandshake, NULL);
}