RFC 1191
When a router is unable to forward a datagram because it exceeds the
MTU of the next-hop network and its Don't Fragment bit is set, the
router is required to return an ICMP Destination Unreachable message
to the source of the datagram, with the Code indicating
"fragmentation needed and DF set". To support the Path MTU Discovery
technique specified in this memo, the router MUST include the MTU of
that next-hop network in the low-order 16 bits of the ICMP header
field that is labelled "unused" in the ICMP specification [7]. The
high-order 16 bits remain unused, and MUST be set to zero. Thus, the
message has the following format:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 3 | Code = 4 | Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| unused = 0 | Next-Hop MTU |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Internet Header + 64 bits of Original Datagram Data |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
RFC 1185
Packet Too Big Message
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Code | Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MTU |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| As much of invoking packet |
+ as will fit without the ICMPv6 packet +
| exceeding 576 octets |
IPv6 Fields:
Destination Address
Copied from the Source Address field of the invoking
packet.
ICMPv6 Fields:
Type 2
Code 0
MTU The Maximum Transmission Unit of the next-hop link.
Description
A Packet Too Big MUST be sent by a router in response to a packet
that it cannot forward because the packet is larger than the MTU of
the outgoing link. The information in this message is used as part
of the Path MTU Discovery process [RFC-1191].
Signed-off-by: wangchen <wangchen41@xiaomi.com>
Allocate the device buffer only if the protocol really need to send data.
not all protocols require the driver to prepare additional iob before
sending, especially UDP, each iob reserves l2/l3 header in advance
after prepare write buffer, net device could reuse this entry to send directly
Signed-off-by: chao an <anchao@xiaomi.com>
Previously, the devif_poll works in this flow:
devif_poll_xx -> bstop = callback -> continue if !bstop -> poll another
Now we split the polling and callback, so it should work like:
devif_poll_connections -> return true if callback need to be called
-> bstop = callback -> loop if !bstop -> poll again
Conditions:
poll_connections == 0, d_len == 0, break, return 0
poll_connections == 1, d_len == 0, break, return 1 (other stop case,
don't callback)
poll_connections == 1, d_len > 0, callback == 1, break, return 1
poll_connections == 1, d_len > 0, callback == 0, loop
Signed-off-by: Zhe Weng <wengzhe@xiaomi.com>
If ipforward consumes all the IOB, devif_poll will not poll any more. Without polling, ipforward will not release any IOB, then all the network stack may fail with no IOB available.
Signed-off-by: Zhe Weng <wengzhe@xiaomi.com>
Loopback device will consume the d_iob packet in upper layer protocol,
in order to avoid null pointer access, reprepare iob buffer before polling connections
Signed-off-by: chao an <anchao@xiaomi.com>
devif_loopback needs to be applied on l2 data, and was broken by commit below, now fix it.
| commit 8850dee746
| Author: chao an <anchao@xiaomi.com>
| Date: Sun Nov 27 03:31:07 2022 +0800
|
| net/devif: move preprocess of txpoll into common code
|
| Signed-off-by: chao an <anchao@xiaomi.com>
Signed-off-by: Zhe Weng <wengzhe@xiaomi.com>
TX poll callback in device lo(loopback) can be replaced by devif_loopback()
from devif_poll() hook, remove duplicate code to reuse this logic
Signed-off-by: chao an <anchao@xiaomi.com>
tcp_timer: eliminated false decrements of conn->timer in case of multiple network adapters.
The false timer decrements sometimes provoked TCP spurious retransmissions due to premature timeouts.
Squashed commit of the following:
Author: Gregory Nutt <gnutt@nuttx.org>
Ran nxstyle against many of the affected files. But this job was too big for today. Many of the network drivers under arch are highly non-compiant and generate many, many faults from nxstyle. Those will have to be visited again another day.
Author: Xiang Xiao <xiaoxiang@xiaomi.com>
This effects all network drivers as well as timing related portions of net/: devif_poll_tcp_timer shouldn't be skipped in the multiple card case. devif_timer will be called multiple time in one period if the multiple card exist, the elapsed time calculated for the first callback is right, but the flowing callback in the same period is wrong(very short) because the global variable g_polltimer is used in the calculation. So let's pass the delay time to devif_timer and remove g_polltimer.
net/mld: The MLD logic now compiles and is much less toxic. It still is not a proper MLD implementation: (1) It is basically a port of IGMP, tweaked to work with IPv6 and ICMPv6 MLD messages, (2) it needs a proper analysis and comparison with RFC 3810, and (3) it is completely untested. For this reason, it will remain EXPERIMENTAL for some time.
net/mld: Add some missing macros, more fixes related to IPv6 vs IPv4 types,
net/mld: More compilation cleaning. Most fixups for IPv6 vs IPv4 types.
net/mld: Hook crudely converted .c files into build system and resolve a few of the many, many compilation/design problems.
net/mld: Add support for MLD statistics.
net/mld: Hook in MLD poll and packet transmission logic.
net/mld: Change references to IPv4 definitions to IPv6 definitions; Remove mld_input() since MLD piggybacks on ICMPv6 input. Add functions to catch MLD messages dispatched by ICMPv6 input logic.
net/mld: As a starting point, copy all net/igmp/*.c files to net/mld/. and change all occurrences of igmp (or IGMP) to mld (or MLD).
net/mld: More compilation cleaning. Most fixups for IPv6 vs IPv4 types.
net/mld: Hook crudely converted .c files into build system and resolve a few of the many, many compilation/design problems.
net/mld: Add support for MLD statistics.
net/mld: Hook in MLD poll and packet transmission logic.
net/mld: Change references to IPv4 definitions to IPv6 definitions; Remove mld_input() since MLD piggybacks on ICMPv6 input. Add functions to catch MLD messages dispatched by ICMPv6 input logic.
net/mld: As a starting point, copy all net/igmp/*.c files to net/mld/. and change all occurrences of igmp (or IGMP) to mld (or MLD).
Squashed commit of the following:
sched: Rename all use of system_t to clock_t.
syscall: Rename all use of system_t to clock_t.
net: Rename all use of system_t to clock_t.
libs: Rename all use of system_t to clock_t.
fs: Rename all use of system_t to clock_t.
drivers: Rename all use of system_t to clock_t.
arch: Rename all use of system_t to clock_t.
include: Remove definition of systime_t; rename all use of system_t to clock_t.
Squashed commit of the following:
wireless/bluetooth: Some small changes that gets to a clean compile by just eliminating some incorrect implementations (still with a lot of warnings. The logic is still incomplete but now not so lethal.
wireless/bluetooth: Restructuring: Connection interfaces should internal to wireless/bluetooth. include/nuttx/wireless/bt_conn.h removed and merged with wireless/bluetooth/bt_conn.h. Several fix to get closer to bt_netdev.c compiling. Need to design some not interfaces and use some existing interfaces to send and receiv packets.
wireless/bluetooth: Some organization with some network device compile errors fixed. Still not even close to compiling.
net/bluetooth: Fix numerous compile issues; Still open design issues with regard to the interface with the Bluetooth stack.
wireless/bluetooth: Create bt_netdev.c with a crude copy of mac802154_netdev.c. Does not not even compile yet.
include/nuttx/net: Add bluetooth.h. Content is not yet correct.
net/netpackets: Add bluetooth.h. Update net/bluetooth to use new socket address definition.
net/bluetooth: Some fixes for initial build.
net/bluetooth: Add initial support for Bluetooth sockets. The initial cut is just the a clone of the IEEE 802.15.4 socket support with name changes.
net/ieee802154: Fix some typos noted when cloning to create net/bluetooth.
Squashed commit of the following:
net/icmpv6: IPPROT_ICMP6 socket logic now builds without error.
net/icmpv6: Add support for read-ahead and poll(). Initial commit is just cloned from ICMP with the appropriate name changes.
configs/: All defconfig filess that include CONFIG_NET_ICMPv6_SOCKET=y need to select CONFIG_SYSTEM_PING6=y and deselect CONFIG_DISABLE_POLL.
Update NSH documention to show that ping6 is now a built in command.
net/icmpv6: Add icmpv6_sendto.c and icmpv6_recvfrom.c. Initial versions are just clones from icmp/ with appropriate name changes.
net/icmpv6: Clone some ICMP socket logic as the beginning of support for ICMPv6 socket support.
Rename CONFIG_NET_ICMPv6_PING to CONFIG_NET_ICMPv6_SOCKET. Move prototype for icmpv6_ping from include/nuttx/net/icmpv6 to net/icmpv6/icmpv6.h
Squashed commit of the following:
net/icmp: Finishes off icmp_recvfrom().
net/icmp: Add readahead support for IPPROTO_ICMP sockets.
net/icmp: Add poll() support for IPPROTO_ICMP sockets.
net/icmp: Add a connection structure for IPPROTO_ICMP sockets.
net/icmp: Implements sendto for the IPPROTO_ICMP socket.
net/icmp: Move icmp_sendto() and icmp_recvfrom() to separate files. They are likely to be complex (when they are implemented).
net/icmp: Hook IPPROTO_ICMP sockets into network. Fix some naming collisions. Still missing basic ICMP send/receive logic.
configs: apps/system/ping current need poll() enabled.
configs: All defconfig files that use to enable low-level support must now enabled CONFIG_SYSTEM_PING.
net/icmp: Adds basic build framework to support IPPROTO_ICMP sockets.
commit 2a3ab1652a2c95bcfc8be8380fc7cbdcb6472938
Author: Gregory Nutt <gnutt@nuttx.org>
Date: Sat Aug 19 08:44:31 2017 -0600
PF_IEEE802154: Finish some missing bind() logic. Add configs/sim configuration for testing.
commit 59be4b846a6e3bfe82087a888e3fdac9c3c414e5
Author: Gregory Nutt <gnutt@nuttx.org>
Date: Fri Aug 18 19:30:04 2017 -0600
PF_IEEE802154: More renaming to decouple 6LoPAN from radios in general.
commit 69fabb1aea76e54381bdc13de28a3f1441fb42f4
Author: Gregory Nutt <gnutt@nuttx.org>
Date: Fri Aug 18 19:21:11 2017 -0600
PF_IEEE802154: Missed a few renamings.
commit ff0af1bb25567720934cc1c2a721ccd92cc35f89
Author: Gregory Nutt <gnutt@nuttx.org>
Date: Fri Aug 18 17:46:58 2017 -0600
PF_IEEE802154: A few bugfixes
commit 01c7c84afd00cf907d280d30cfaf0fb2cf90e02e
Author: Gregory Nutt <gnutt@nuttx.org>
Date: Fri Aug 18 17:01:31 2017 -0600
PF_IEEE802154: A few bugfixes
commit dcef4056d1c1488c93151135f3b7106977faa903
Author: Gregory Nutt <gnutt@nuttx.org>
Date: Fri Aug 18 16:31:05 2017 -0600
PF_IEEE802154: Bring in framework for sendto/recvfrom. Currently just a crude port of functions from net/pkt and do not provide the implemenation needed.
commit 68c5b7b6dd3ab7eb2d0c19890abb38e6561b140e
Author: Gregory Nutt <gnutt@nuttx.org>
Date: Fri Aug 18 15:18:31 2017 -0600
Trivial fix to typo in comment
commit fd0af534c089569ccdbd59f13b85453de0a653ad
Author: Gregory Nutt <gnutt@nuttx.org>
Date: Fri Aug 18 15:07:20 2017 -0600
PF_IEEE802154: Add device lookup logic; Rename some things that used to be used only by 6LoWPAN but now must be shared with PF_IEEE802154 and need more generic naming.
commit 4fc80a1659f1c699b050775cefc7f6b631b46114
Author: Gregory Nutt <gnutt@nuttx.org>
Date: Fri Aug 18 13:49:54 2017 -0600
PF_IEEE802154: Add driver poll logic.
commit d83f71992df8764faa93f9425f1a7602a758f730
Author: Gregory Nutt <gnutt@nuttx.org>
Date: Fri Aug 18 13:28:59 2017 -0600
PF_IEEE802154: Add frame input function.
commit 77561b8c4d5d7be1f8d8eb62cf1a07229afe2048
Author: Gregory Nutt <gnutt@nuttx.org>
Date: Fri Aug 18 12:46:29 2017 -0600
PF_IEEE802154: Socket type should be SOCK_DGRAM. Hook in socket interface.
commit c0f90350282e9905d7f26a1b30f04cc6d6794648
Merge: 8b518abfd0 169c55e546
Author: Gregory Nutt <gnutt@nuttx.org>
Date: Fri Aug 18 09:36:32 2017 -0600
Merge remote-tracking branch 'origin/master' into pf_ieee802154
commit 8b518abfd07d492f5148f2c5fdf65604de9822da
Author: Gregory Nutt <gnutt@nuttx.org>
Date: Fri Aug 18 09:35:39 2017 -0600
PF_IEEE802154: Add initialization and connection management logic.
commit 98b62620b3cb420041d8ad14204f9410a8aace8c
Author: Gregory Nutt <gnutt@nuttx.org>
Date: Fri Aug 18 07:52:51 2017 -0600
PF_IEEE802154: Add basic build support and socket interface framework.
