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>
added IPV6_RECVHOPLIMIT support so that fd of SOCK_RAW ICMPV6 can obtain ttl
information, some network related tools use this feature.
Signed-off-by: zhanghongyu <zhanghongyu@xiaomi.com>
The third-party library we are porting will send and receive ICMPV6 messages
(router_advert / router_solicit / neighbor_advert / neighbor_solicit etc.)
from the user mode itself, so we added the SOCK_RAW related implementation
for ICMPV6.
Signed-off-by: zhanghongyu <zhanghongyu@xiaomi.com>
SOCK_CTRL is added to provide special control over network drivers
and daemons. Currently, SOCK_DGRAM and SOCK_STREAM perform this control,
but these use socket resources. In the case of usersocket in particular,
this is a waste of the device's limited socket resources.
SOCK_CTRL is added to provide special control over network drivers
and daemons. Currently, SOCK_DGRAM and SOCK_STREAM perform this control,
but these use socket resources. In the case of usersocket in particular,
this is a waste of the device's limited socket resources.
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>
When trying to use iperf2, we found it comsumes all the IOB when sending UDP packets, then devif_poll has no IOB to send the packet out, so speed drops to 0 and never recovers.
Signed-off-by: Zhe Weng <wengzhe@xiaomi.com>
Fix icmpv6_reply logic broken by commit 48311cc61f and 391b501639.
- 48311cc61f "Fix unaligned memory access when creating ICMP Port Unreachable messages"
- It removed `htonl` function outside `data`, then the byte order may be wrong, so add `htons` back.
- 391b501639 "net: extract l3 header build code into new functions"
- It mis-removed the `memmove`, and the icmpv6 has no payload copied after this commit.
Signed-off-by: Zhe Weng <wengzhe@xiaomi.com>
The `datalen` indicates the whole len of original packet, which will become the payload inside icmpv6 packet.
Using `datalen = (ipv4->len[0] << 8) + ipv4->len[1]` in icmp_reply is correct, because it includes IPv4 header, but when coming to IPv6, the `len` does not include the header, so we need to add it back.
Signed-off-by: Zhe Weng <wengzhe@xiaomi.com>
since it is impossible to track producer and consumer
correctly if TCP/IP stack pass IOB directly to netdev
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
Net poll teardown is not protected by net lock, if the conn is released
before teardown, the assertion failure will be triggered during free dev
callback, this patch will add the net lock around net poll teardown to
fix race condition
nuttx/libs/libc/assert/lib_assert.c:36
nuttx/net/devif/devif_callback.c:85
nuttx/net/tcp/tcp_netpoll.c:405
nuttx/fs/vfs/fs_poll.c:244
nuttx/fs/vfs/fs_poll.c:500
Signed-off-by: chao.an <anchao@xiaomi.com>
