RFC2001: TCP Slow Start, Congestion Avoidance, Fast Retransmit,
and Fast Recovery Algorithms
...
3. Fast Retransmit
Modifications to the congestion avoidance algorithm were proposed in
1990 [3]. Before describing the change, realize that TCP may
generate an immediate acknowledgment (a duplicate ACK) when an out-
of-order segment is received (Section 4.2.2.21 of [1], with a note
that one reason for doing so was for the experimental fast-
retransmit algorithm). This duplicate ACK should not be delayed.
The purpose of this duplicate ACK is to let the other end know that a
segment was received out of order, and to tell it what sequence
number is expected.
Since TCP does not know whether a duplicate ACK is caused by a lost
segment or just a reordering of segments, it waits for a small number
of duplicate ACKs to be received. It is assumed that if there is
just a reordering of the segments, there will be only one or two
duplicate ACKs before the reordered segment is processed, which will
then generate a new ACK. If three or more duplicate ACKs are
received in a row, it is a strong indication that a segment has been
lost. TCP then performs a retransmission of what appears to be the
missing segment, without waiting for a retransmission timer to
expire.
Change-Id: Ie2cbcecab507c3d831f74390a6a85e0c5c8e0652
Signed-off-by: chao.an <anchao@xiaomi.com>
The number of available iobs is already sub in iob_navail(true) on line 114
net/tcp/tcp_recvwindow.c:
...
73 uint16_t tcp_get_recvwindow(FAR struct net_driver_s *dev)
...
114 niob_avail = iob_navail(true);
Change-Id: I230927904d8db08ed8d95d7fa18c5c5fce08aa5e
Signed-off-by: chao.an <anchao@xiaomi.com>
Add a fallback mechanism to ensure that there are still available
iobs for an free connection, Guarantees all connections will have
a minimum threshold iob to keep the connection not be hanged.
Change-Id: I59bed98d135ccd1f16264b9ccacdd1b0d91261de
Signed-off-by: chao.an <anchao@xiaomi.com>
Patch fixes following build error when
CONFIG_NET_IPv6 && !CONFIG_NET_ICMPv6 && CONFIG_NET_ETHERNET:
nuttx/staging/libnet.a(neighbor_ethernet_out.o): In function `neighbor_ethernet_out':
nuttx/net/neighbor/neighbor_ethernet_out.c:188: undefined reference to `icmpv6_solicit'
IPv6 without ICMPv6 is not very useful, but at least this patch
allows neighbor_ethernet_out() to be used with a packet socket or
with multicast address (point-to-point IPv6 links) even in that case.
Signed-off-by: Juha Niskanen <juha.niskanen@haltian.com>
The following nxstyle errors are known.
They are a part of the copyright notice.
net/igmp/igmp_poll.c:22:82: error: Long line found
net/igmp/igmp_poll.c:29:82: error: Long line found
The following nxstyle errors are known.
They are a part of the copyright notice.
net/igmp/igmp_mcastmac.c:22:82: error: Long line found
net/igmp/igmp_mcastmac.c:29:82: error: Long line found
The following nxstyle errors are intentionally left
because they are a part of the copyright notice.
net/igmp/igmp_join.c:22:82: error: Long line found
net/igmp/igmp_join.c:29:82: error: Long line found
remove the connection assertion since the instance will be invalid
if the network device has been taken down.
net/netdev/netdev_ioctl.c:
1847 void netdev_ifdown(FAR struct net_driver_s *dev)
1848 {
...
1871 /* Notify clients that the network has been taken down */
1872
1873 devif_dev_event(dev, NULL, NETDEV_DOWN);
...
1883 }
Change-Id: I492b97b5ebe035ea67bbdd7ed635cb13d085e89c
Signed-off-by: chao.an <anchao@xiaomi.com>
In the current net stack implementation, there is no mechanism
for notifying the loss of the wireless connection, if the network
is disconnected then application sends data packets through tcp,
the tcp_timer will keep retrying fetch the ack for awhile, the
connection status will not be able to be switched timely.
Change-Id: I84d1121527edafc6ee6ad56ba164838694e7e11c
Signed-off-by: chao.an <anchao@xiaomi.com>
Fixes an issue where tcp sockets with activated keepalives stalled and
were not properly closed. Poll would not indicate a POLLHUP and therefore
locks down the application.
* tcp_conn_s.tcp_conn_s & tcp_conn_s.keepintvl changed to uint32_t
According RFC1122 keepidle MUST have a default of 2 hours.
N/A
Cause of curr maybe NULL, and following logic can handle this
Change-Id: I999c051a8f2e2698400fc8793ba068073a306972
Signed-off-by: ligd <liguiding1@xiaomi.com>
1.Reduce the default size of task_group_s(~512B each task)
2.Scale better between simple and complex application
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
Change-Id: Ia872137504fddcf64d89c48d6f0593d76d582710
to save the preserved space(1KB) and also avoid the heap overhead
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
Change-Id: I694073f68e1bd63960cedeea1ddec441437be025
Found by clang-check:
tcp/tcp_timer.c:185:15: warning: Value stored to 'result' is never read
result = tcp_callback(dev, conn, TCP_TIMEDOUT);
^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
tcp/tcp_timer.c:264:23: warning: Value stored to 'result' is never read
result = tcp_callback(dev, listener, TCP_TIMEDOUT);
^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
tcp/tcp_timer.c:300:19: warning: Value stored to 'result' is never read
result = tcp_callback(dev, conn, TCP_TIMEDOUT);
^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
3 warnings generated.
Add flags argument into sendto() and recvfrom() APIs for MSG_* flags can
handling in the daemon.
However, MSG_DONTWAIT should process in usrsock, so it unnecessary to pass to
the daemon like O_NONBLOCK.
Make.dep file should be updated by .config changed after first make.
There are 2 cases affected for this problem:
1) Add source files by config symbol
2) Include header files in #ifdef directive
These 2 cases may not be included in Make.dep and this may prevent the
differential build from working correctly.
igmp/igmp_timer.c: In function ‘igmp_timeout’:
igmp/igmp_timer.c:163:11: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
163 | group = (FAR struct igmp_group_s *)arg;
| ^
igmp/igmp_timer.c: In function ‘igmp_startticks’:
igmp/igmp_timer.c:200:55: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
200 | ret = wd_start(group->wdog, ticks, igmp_timeout, 1, (uint32_t)group);
| ^
igmp/igmp_timer.c:200:38: warning: passing argument 3 of ‘wd_start’ from incompatible pointer type [-Wincompatible-pointer-types]
200 | ret = wd_start(group->wdog, ticks, igmp_timeout, 1, (uint32_t)group);
| ^~~~~~~~~~~~
| |
| void (*)(int, uint32_t, ...) {aka void (*)(int, unsigned int, ...)}
In file included from igmp/igmp_timer.c:50:
/home/xiaoxiang/mirtos/nuttx/include/nuttx/wdog.h:233:53: note: expected ‘wdentry_t’ {aka ‘void (*)(int, long unsigned int, ...)’} but argument is of type ‘void (*)(int, uint32_t, ...)’ {aka ‘void (*)(int, unsigned int, ...)’}
233 | int wd_start(WDOG_ID wdog, int32_t delay, wdentry_t wdentry, int argc, ...);
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
Change-Id: I153355f85f583f5441d97a0b1278bce167eb3fd0
