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Avoid queueing into circbuffer when the channel is about to close

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This commit is contained in:
Matt Johnston 2015-11-19 23:52:52 +08:00
parent 87373be960
commit 90c3a74b2a
1 changed files with 42 additions and 46 deletions
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88
common-channel.c
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@ -42,7 +42,7 @@ static void send_msg_channel_open_failure(unsigned int remotechan, int reason,
static void send_msg_channel_open_confirmation(struct Channel* channel,
unsigned int recvwindow,
unsigned int recvmaxpacket);
static void writechannel(struct Channel* channel, int fd, circbuffer *cbuf,
static int writechannel(struct Channel* channel, int fd, circbuffer *cbuf,
const unsigned char *moredata, unsigned int *morelen);
static void send_msg_channel_window_adjust(struct Channel *channel,
unsigned int incr);
@ -100,15 +100,6 @@ void chancleanup() {
TRACE(("leave chancleanup"))
}
static void
chan_initwritebuf(struct Channel *channel)
{
dropbear_assert(channel->writebuf->size == 0 && channel->recvwindow == 0);
cbuf_free(channel->writebuf);
channel->writebuf = cbuf_new(opts.recv_window);
channel->recvwindow = opts.recv_window;
}
/* Create a new channel entry, send a reply confirm or failure */
/* If remotechan, transwindow and transmaxpacket are not know (for a new
* outgoing connection, with them to be filled on confirmation), they should
@ -167,8 +158,8 @@ static struct Channel* newchannel(unsigned int remotechan,
newchan->await_open = 0;
newchan->flushing = 0;
newchan->writebuf = cbuf_new(0); /* resized later by chan_initwritebuf */
newchan->recvwindow = 0;
newchan->writebuf = cbuf_new(opts.recv_window);
newchan->recvwindow = opts.recv_window;
newchan->extrabuf = NULL; /* The user code can set it up */
newchan->recvdonelen = 0;
@ -379,7 +370,6 @@ void channel_connect_done(int result, int sock, void* user_data, const char* UNU
{
channel->readfd = channel->writefd = sock;
channel->conn_pending = NULL;
chan_initwritebuf(channel);
send_msg_channel_open_confirmation(channel, channel->recvwindow,
channel->recvmaxpacket);
TRACE(("leave channel_connect_done: success"))
@ -436,7 +426,7 @@ static void send_msg_channel_eof(struct Channel *channel) {
}
#ifndef HAVE_WRITEV
static void writechannel_fallback(struct Channel* channel, int fd, circbuffer *cbuf,
static int writechannel_fallback(struct Channel* channel, int fd, circbuffer *cbuf,
const unsigned char *UNUSED(moredata), unsigned int *morelen) {
unsigned char *circ_p1, *circ_p2;
@ -455,23 +445,24 @@ static void writechannel_fallback(struct Channel* channel, int fd, circbuffer *c
if (errno != EINTR && errno != EAGAIN) {
TRACE(("channel IO write error fd %d %s", fd, strerror(errno)))
close_chan_fd(channel, fd, SHUT_WR);
return DROPBEAR_FAILURE;
}
} else {
cbuf_incrread(cbuf, written);
channel->recvdonelen += written;
}
cbuf_incrread(cbuf, written);
channel->recvdonelen += written;
return DROPBEAR_SUCCESS;
}
#endif /* !HAVE_WRITEV */
#ifdef HAVE_WRITEV
static void writechannel_writev(struct Channel* channel, int fd, circbuffer *cbuf,
static int writechannel_writev(struct Channel* channel, int fd, circbuffer *cbuf,
const unsigned char *moredata, unsigned int *morelen) {
struct iovec iov[3];
unsigned char *circ_p1, *circ_p2;
unsigned int circ_len1, circ_len2;
int io_count = 0;
int cbuf_written;
ssize_t written;
cbuf_readptrs(cbuf, &circ_p1, &circ_len1, &circ_p2, &circ_len2);
@ -503,7 +494,7 @@ static void writechannel_writev(struct Channel* channel, int fd, circbuffer *cbu
From common_recv_msg_channel_data() then channelio().
The second call may not have any data to write, so we just return. */
TRACE(("leave writechannel, no data"))
return;
return DROPBEAR_SUCCESS;
}
if (morelen) {
@ -517,29 +508,32 @@ static void writechannel_writev(struct Channel* channel, int fd, circbuffer *cbu
if (errno != EINTR && errno != EAGAIN) {
TRACE(("channel IO write error fd %d %s", fd, strerror(errno)))
close_chan_fd(channel, fd, SHUT_WR);
return DROPBEAR_FAILURE;
}
} else {
int cbuf_written = MIN(circ_len1+circ_len2, (unsigned int)written);
cbuf_incrread(cbuf, cbuf_written);
if (morelen) {
*morelen = written - cbuf_written;
}
channel->recvdonelen += written;
}
}
cbuf_written = MIN(circ_len1+circ_len2, (unsigned int)written);
cbuf_incrread(cbuf, cbuf_written);
if (morelen) {
*morelen = written - cbuf_written;
}
channel->recvdonelen += written;
return DROPBEAR_SUCCESS;
}
#endif /* HAVE_WRITEV */
/* Called to write data out to the local side of the channel.
Writes the circular buffer contents and also the "moredata" buffer
if not null. Will ignore EAGAIN */
static void writechannel(struct Channel* channel, int fd, circbuffer *cbuf,
if not null. Will ignore EAGAIN.
Returns DROPBEAR_FAILURE if writing to fd had an error and the channel is being closed, DROPBEAR_SUCCESS otherwise */
static int writechannel(struct Channel* channel, int fd, circbuffer *cbuf,
const unsigned char *moredata, unsigned int *morelen) {
int ret = DROPBEAR_SUCCESS;
TRACE(("enter writechannel fd %d", fd))
#ifdef HAVE_WRITEV
writechannel_writev(channel, fd, cbuf, moredata, morelen);
ret = writechannel_writev(channel, fd, cbuf, moredata, morelen);
#else
writechannel_fallback(channel, fd, cbuf, moredata, morelen);
ret = writechannel_fallback(channel, fd, cbuf, moredata, morelen);
#endif
/* Window adjust handling */
@ -555,6 +549,7 @@ static void writechannel(struct Channel* channel, int fd, circbuffer *cbuf,
channel->recvwindow <= cbuf_getavail(channel->extrabuf));
TRACE(("leave writechannel"))
return ret;
}
@ -829,6 +824,7 @@ void common_recv_msg_channel_data(struct Channel *channel, int fd,
unsigned int buflen;
unsigned int len;
unsigned int consumed;
int res;
TRACE(("enter recv_msg_channel_data"))
@ -861,7 +857,7 @@ void common_recv_msg_channel_data(struct Channel *channel, int fd,
/* Attempt to write the data immediately without having to put it in the circular buffer */
consumed = datalen;
writechannel(channel, fd, cbuf, buf_getptr(ses.payload, datalen), &consumed);
res = writechannel(channel, fd, cbuf, buf_getptr(ses.payload, datalen), &consumed);
datalen -= consumed;
buf_incrpos(ses.payload, consumed);
@ -869,17 +865,20 @@ void common_recv_msg_channel_data(struct Channel *channel, int fd,
/* We may have to run throught twice, if the buffer wraps around. Can't
* just "leave it for next time" like with writechannel, since this
* is payload data */
len = datalen;
while (len > 0) {
buflen = cbuf_writelen(cbuf);
buflen = MIN(buflen, len);
* is payload data.
* If the writechannel() failed then remaining data is discarded */
if (res == DROPBEAR_SUCCESS) {
len = datalen;
while (len > 0) {
buflen = cbuf_writelen(cbuf);
buflen = MIN(buflen, len);
memcpy(cbuf_writeptr(cbuf, buflen),
buf_getptr(ses.payload, buflen), buflen);
cbuf_incrwrite(cbuf, buflen);
buf_incrpos(ses.payload, buflen);
len -= buflen;
memcpy(cbuf_writeptr(cbuf, buflen),
buf_getptr(ses.payload, buflen), buflen);
cbuf_incrwrite(cbuf, buflen);
buf_incrpos(ses.payload, buflen);
len -= buflen;
}
}
TRACE(("leave recv_msg_channel_data"))
@ -993,8 +992,6 @@ void recv_msg_channel_open() {
channel->prio = DROPBEAR_CHANNEL_PRIO_BULK;
}
chan_initwritebuf(channel);
/* success */
send_msg_channel_open_confirmation(channel, channel->recvwindow,
channel->recvmaxpacket);
@ -1137,7 +1134,6 @@ int send_msg_channel_open_init(int fd, const struct ChanType *type) {
/* Outbound opened channels don't make use of in-progress connections,
* we can set it up straight away */
chan_initwritebuf(chan);
/* set fd non-blocking */
setnonblocking(fd);