| Message ID | 20230814133253.4150-2-maxim.uvarov@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | net/lwip: add lwip library for the network stack | expand |
On Mon, Aug 14, 2023 at 07:32:40PM +0600, Maxim Uvarov wrote: > Add initial documentation of lwIP network IP stack integration > to the U-Boot (net_lwip.rst). > > Signed-off-by: Maxim Uvarov <maxim.uvarov@linaro.org> > Reviewed-by: Simon Glass <sjg@chromium.org> > --- > doc/develop/index.rst | 1 + > doc/develop/net_lwip.rst | 64 ++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 65 insertions(+) > create mode 100644 doc/develop/net_lwip.rst > > diff --git a/doc/develop/index.rst b/doc/develop/index.rst > index 5b230d0321..4764990f25 100644 > --- a/doc/develop/index.rst > +++ b/doc/develop/index.rst > @@ -48,6 +48,7 @@ Implementation > spl > falcon > uefi/index > + net_lwip > vbe > version > > diff --git a/doc/develop/net_lwip.rst b/doc/develop/net_lwip.rst > new file mode 100644 > index 0000000000..bdd2c921b3 > --- /dev/null > +++ b/doc/develop/net_lwip.rst > @@ -0,0 +1,64 @@ > +.. SPDX-License-Identifier: GPL-2.0+ > + > +LWIP IP stack intergation for U-Boot > +==================================== > + > +Intro > +----- > + > +LWIP is a library implementing network protocols, which is commonly used > +on embedded devices. > + > +https://savannah.nongnu.org/projects/lwip/ > + > +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: LwIP is very customizable You can skip the 'I' here, it's not a personal project. Something along the lines of 'the second variant was chosen ...' would work > + with defines for features, memory size, types of allocation, some internal > + types and platform specific code. It turned out easier 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). > +For now only raw API is supported. > + > +In raw IP mode a callback function for RX path is registered and will be called > +when packet is passed to the IP stack and is ready for the application. > + > +Example is unmodified working ping example from lwip sources which registered One example is the unmodified etc > +the callback: > + > +.. code-block:: c > + > + 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) > + > +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. 'That way we can leave the driver code unmodified and consume packets once they are ready' Thanks /Ilias > -- > 2.30.2 >
diff --git a/doc/develop/index.rst b/doc/develop/index.rst index 5b230d0321..4764990f25 100644 --- a/doc/develop/index.rst +++ b/doc/develop/index.rst @@ -48,6 +48,7 @@ Implementation spl falcon uefi/index + net_lwip vbe version diff --git a/doc/develop/net_lwip.rst b/doc/develop/net_lwip.rst new file mode 100644 index 0000000000..bdd2c921b3 --- /dev/null +++ b/doc/develop/net_lwip.rst @@ -0,0 +1,64 @@ +.. SPDX-License-Identifier: GPL-2.0+ + +LWIP IP stack intergation for U-Boot +==================================== + +Intro +----- + +LWIP is a library implementing network protocols, which is commonly used +on embedded devices. + +https://savannah.nongnu.org/projects/lwip/ + +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: LwIP is very customizable + with defines for features, memory size, types of allocation, some internal + types and platform specific code. It turned out easier 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). +For now only raw API is supported. + +In raw IP mode a callback function for RX path is registered and will be called +when packet is passed to the IP stack and is ready for the application. + +Example is unmodified working ping example from lwip sources which registered +the callback: + +.. code-block:: c + + 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) + +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.