On Thu, 11 May 2023 at 09:52, Tom Rini trini@konsulko.com wrote:
On Fri, May 05, 2023 at 10:25:24AM +0000, Maxim Uvarov wrote:
Greetings,
This RFC patchset is an attempt to try to use an already existing IP
network stack inside U-boot.
U-Boot recently got basic TCP/IP support, implementing wget, but in
order to get a full IP stack
with new features (e.g ipv6), it would be preferable to use an
established embedded ip library,
instead of rewriting the code from scratch.
For this experiment LWIP network stack was selected: https://savannah.nongnu.org/git/?group=lwip
LWIP main features include:
- Protocols: IP, IPv6, ICMP, ND, MLD, UDP, TCP, IGMP, ARP, PPPoS, PPPoE
- DHCP client, DNS client (incl. mDNS hostname resolver), AutoIP/APIPA
(Zeroconf),
SNMP agent (v1, v2c, v3, private MIB support & MIB compiler)
- APIs: specialized APIs for enhanced performance, optional
Berkeley-alike socket API
- Extended features: IP forwarding over multiple network interfaces, TCP
congestion control,
RTT estimation and fast recovery/fast retransmit
- Addon applications: HTTP(S) server, SNTP client, SMTP(S) client, ping,
NetBIOS nameserver,
mDNS responder, MQTT client, TFTP server.
This RFC work is a demo to enable lwIP (lightweight IP) which is a
widely used open-source
TCP/IP stack designed for embedded systems for U-boot. That will allow
using already
written network applications for microcontrollers.
lwIP is licensed under a BSD-style license:
http://lwip.wikia.com/wiki/License.
Which should be compatible with u-boot.
In the current RFC I tried to use minimal changes to better see how LWIP
code can be embedded into
U-boot. Patches implement ping and wget commands work. Both commands are
currently copy pasting and
reusing lwIP examples. Whether we want to add the final application in
U-Boot or lwIP is up to
discussion, but the current approach was the easiest one for an RFC.
I'm honestly not sure this is the most useful way of doing an RFC. The long term goal would be that we replace our existing net/ with lwIP, yes? So what I'd see as more valuable is what it looks like to limit yourself to either sandbox or some QEMU target, disable the current network stack, and instead use lwIP to support just cmd/net.c so that the scope of the conversion is visible. Then the size comparison you do should be between platform + net + cmd/net.c (and the rest of networking turned off) and platform + lwip + cmd/net.c converted.
-- Tom
Is there any acceptance criteria for size? If we say that additing lwip will add about 48kb and removing current code will also release some kbs. How size is critical here or it's just numbers good to know?
BR, Maxim.