Hi Maxim, On Thu, Jun 29, 2023 at 06:34:29PM +0600, Maxim Uvarov wrote: > Just add inital README.lwip doc.
We'll need a more accurate description for this. The first paragraph of the documentation you are adding would do > > Signed-off-by: Maxim Uvarov <maxim.uva...@linaro.org> > --- > doc/README.lwip | 90 +++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 90 insertions(+) > create mode 100644 doc/README.lwip > > diff --git a/doc/README.lwip b/doc/README.lwip > new file mode 100644 > index 0000000000..16f41049ab > --- /dev/null > +++ b/doc/README.lwip > @@ -0,0 +1,90 @@ > + RFC LWIP IP stack intergation for U-boot > + ---------------------------------------- > + > +Reliable and bug free IP stack is usually an issue when you are trying to > write it I am not sure about the bug free part :). Just move this entire paragraph as part of the commit message and remove the 'RFC' parts. > +from scratch. It looks like not, but when addinging new features it will be > chelledging. > +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 license: > +lwIP is licensed under a BSD-style license: > http://lwip.wikia.com/wiki/License. > + > +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 > + > +U-boot implementation details: > + > +1. In general we can build lwIP as .a library and link it against u-boot or > compile it in > +the U-boot tree in the same way as other U-boot files. There are few reasons > why I selected > +the second variant: iwIP is very customizable with defines for features, > memory size, types of > +allocation, some internal types and platform specific code. And it was more > easy to enable/disable > + debug which is also done with defines, and is needed periodically. > + > +2. lwIP has 2 APIs - raw mode and sequential (as lwIP names it, or socket > API as we name it in Linux). > + This RFC implements only raw API as the proof of work. > + > +Raw IP means that the call back function for RX path is registered and will > be called when packet > +data passes the IP stack and is ready for the application. > + > +This RFC has an unmodified working ping example from lwip sources which > registeres this callback. > + ping_pcb = raw_new(IP_PROTO_ICMP); > + raw_recv(ping_pcb, ping_recv, NULL); <- ping_recv is app callback. > + raw_bind(ping_pcb, IP_ADDR_ANY) > + > +Socket API also gives nice advantages due it will be easy to port linux > socket applications to u-boot. > +I.e. lwIP sockets compatible with the linux ones. But that will require RX > thread running in the background. > +So that means we need some kind of scheduler, locking and threading support > or find some other solution. > + > +3. Input and output > + > +RX packet path is injected to U-boot eth_rx() polling loop and TX patch is > in eth_send() accordingly. > +So we do not touch any drivers code and just eat packets when they are ready. > + > +4. Testing > + > +Unmodified ping example can be used. I did ping from qemu/u-boot tap device > on the host: > + > +=> lwip init > +=> lwip ping 192.168.1.2 > +ping: recv 3 ms > +tcpdump on the host: > +5:09:10.925951 ARP, Request who-has 192.168.1.200 tell 192.168.1.200, length > 28 15:09:12.114643 IP6 fe80::38e2:41ff:fec3:8bda > ip6-allrouters: ICMP6, > router solicitation, length 16 15:09:20.370725 ARP, Request who-has > 192.168.1.2 tell 192.168.1.200, length 28 15:09:20.370740 ARP, Reply > 192.168.1.2 is-at 3a:e2:41:c3:8b:da (oui Unknown), length 28 15:09:20.372789 > IP 192.168.1.200 > 192.168.1.2: ICMP echo request, id 44975, seq 1, length 40 > 15:09:20.372810 IP 192.168.1.2 > 192.168.1.200: ICMP echo reply, id 44975, > seq 1, length 40 15:09:25.426636 ARP, Request who-has 192.168.1.200 tell > 192.168.1.2, length 28 15:09:25.426870 ARP, Reply 192.168.1.200 is-at > f6:11:01:02:03:04 (oui Unknown), length 28 > + > + > +5. Wget example > + > +Http server has 192.168.1.2 IP address. (I did not port DNS resolving yet, > +but it's also exist in lwip.) So example just downloads some file with http > +protocol: > + > +Net: eth0: virtio-net#30 > +Hit any key to stop autoboot: 0 > +=> lwip init > +Starting lwIP, local interface IP is 192.168.1.200 > +Initialized LWIP stack > +=> lwip wget http://192.168.1.2/ > +downloading http://192.168.1.2/ to addr 0x40200000 Does wget with lwip work with dns as well? > +downloaded chunk size 294, to addr 0x40200000 > +downloaded chunk size 318, to addr 0x40200126 > +=> md 0x40200000 0x40 > +40200000: 4f44213c 50595443 74682045 0a3e6c6d <!DOCTYPE html>. > +40200010: 6d74683c 3c0a3e6c 64616568 743c0a3e <html>.<head>.<t > +40200020: 656c7469 6c65573e 656d6f63 206f7420 itle>Welcome to > +40200030: 6e69676e 2f3c2178 6c746974 3c0a3e65 nginx!</title>.< > +40200040: 6c797473 200a3e65 62202020 2079646f style>. body > +40200050: 20200a7b 20202020 69772020 3a687464 {. width: > +40200060: 65353320 200a3b6d 20202020 6d202020 35em;. m > +40200070: 69677261 30203a6e 74756120 200a3b6f argin: 0 auto;. > +40200080: 20202020 66202020 2d746e6f 696d6166 font-fami > +40200090: 203a796c 6f686154 202c616d 64726556 ly: Tahoma, Verd > +402000a0: 2c616e61 69724120 202c6c61 736e6173 ana, Arial, sans > +402000b0: 7265732d 0a3b6669 20202020 2f3c0a7d -serif;. }.</ > +402000c0: 6c797473 3c0a3e65 6165682f 3c0a3e64 style>.</head>.< > +402000d0: 79646f62 683c0a3e 65573e31 6d6f636c body>.<h1>Welcom > +402000e0: 6f742065 69676e20 3c21786e 3e31682f e to nginx!</h1> > +402000f0: 3e703c0a 79206649 7320756f 74206565 .<p>If you see t > -- > 2.30.2 > Thanks /Ilias
