Re: [lwip-devel] [PATCHv6 07/14] net/lwip: implement ping cmd

[Simon Glass]

Hi Maxim,

On Fri, 18 Aug 2023 at 03:27, Maxim Uvarov <maxim.uvarov@linaro.org> wrote:
>
>
>
> On Fri, 18 Aug 2023 at 09:10, Simon Glass <sjg@google.com> wrote:
>>
>> Hi Maxim,
>>
>> On Wed, 16 Aug 2023 at 14:15, Maxim Uvarov <maxim.uvarov@linaro.org> wrote:
>> >
>> >
>> >
>> > On Wed, 16 Aug 2023 at 20:39, Simon Glass <sjg@google.com> wrote:
>> >>
>> >> Hi Maxim,
>> >>
>> >> On Wed, 16 Aug 2023 at 03:09, Maxim Uvarov <maxim.uvarov@linaro.org> 
>> >> wrote:
>> >> >
>> >> > On Wed, 16 Aug 2023 at 14:42, Ilias Apalodimas 
>> >> > <ilias.apalodimas@linaro.org>
>> >> > wrote:
>> >> >
>> >> > > On Mon, Aug 14, 2023 at 07:32:46PM +0600, Maxim Uvarov wrote:
>> >> > > >  * can return immediately if previous request was cached or it might
>> >> > > require
>> >> > > > @@ -38,3 +39,28 @@ int ulwip_dhcp(void);
>> >> > > >  *         !0 if error
>> >> > > >  */
>> >> > > >  int ulwip_wget(ulong addr, char *url);
>> >> > > > +
>> >> > > > +/**
>> >> > > > + * ulwip_tftp() - load file with tftp
>> >> > > > + *
>> >> > > > + * Load file with tftp to specific address
>> >> > > > + *
>> >> > > > + * @param addr - address to store downloaded file
>> >> > > > + * @param filename - file name on remote tftp server to download
>> >> > >
>> >> > > Please fix function comments properly
>> >> > >
>> >> > > > + *
>> >> > > > + *
>> >> > > > + * @return 0 if success, !0 if error
>> >> > > > + */
>> >> > > > +int ulwip_tftp(ulong addr, const char *filename);
>> >> > > > +
>> >> > > > +/*
>> >> > > > +* This function creates the ping for  address provided in 
>> >> > > > parameters.
>> >> > > > +* After this function you need to invoke the polling
>> >> > > > +* loop to process network communication.
>> >> > > > +*
>> >> > > > +*
>> >> > > > +* @ping_addr  start address to download result
>> >> > > > +* Return: 0 for success
>> >> > > > +*         !0 if error
>> >> > > > +*/
>> >> > > > +int ulwip_ping(char *ping_addr);
>> >> > > > diff --git a/net/lwip/Makefile b/net/lwip/Makefile
>> >> > > > index 4c6df94807..8b3e843426 100644
>> >> > > > --- a/net/lwip/Makefile
>> >> > > > +++ b/net/lwip/Makefile
>> >> > > > @@ -67,5 +67,6 @@ obj-$(CONFIG_NET) += port/sys-arch.o
>> >> > > >
>> >> > > >  obj-$(CONFIG_CMD_DHCP) += apps/dhcp/lwip-dhcp.o
>> >> > > >  obj-$(CONFIG_CMD_DNS) += apps/dns/lwip-dns.o
>> >> > > > +obj-$(CONFIG_CMD_PING) += apps/ping/
>> >> > > >  obj-$(CONFIG_CMD_TFTPBOOT) += apps/tftp/
>> >> > > >  obj-$(CONFIG_CMD_WGET) += apps/http/
>> >> > > > diff --git a/net/lwip/apps/ping/Makefile 
>> >> > > > b/net/lwip/apps/ping/Makefile
>> >> > > > new file mode 100644
>> >> > > > index 0000000000..dc63feb7b5
>> >> > > > --- /dev/null
>> >> > > > +++ b/net/lwip/apps/ping/Makefile
>> >> > > > @@ -0,0 +1,11 @@
>> >> > > > +ccflags-y += -I$(srctree)/net/lwip/port/include
>> >> > > > +ccflags-y += -I$(srctree)/net/lwip/lwip-external/src/include
>> >> > > -I$(srctree)/net/lwip
>> >> > > > +ccflags-y += -I$(obj)
>> >> > > > +
>> >> > > > +.PHONY: $(obj)/ping.c
>> >> > > > +$(obj)/ping.o: $(obj)/ping.c
>> >> > > > +$(obj)/ping.c:
>> >> > > > +     cp $(srctree)/net/lwip/lwip-external/contrib/apps/ping/ping.c
>> >> > > $(obj)/ping.c
>> >> > > > +
>> >> > > > +obj-$(CONFIG_CMD_PING) += ping.o
>> >> > > > +obj-$(CONFIG_CMD_PING) += lwip_ping.o
>> >> > > > diff --git a/net/lwip/apps/ping/lwip_ping.c
>> >> > > b/net/lwip/apps/ping/lwip_ping.c
>> >> > > > new file mode 100644
>> >> > > > index 0000000000..611fcaf591
>> >> > > > --- /dev/null
>> >> > > > +++ b/net/lwip/apps/ping/lwip_ping.c
>> >> > > > @@ -0,0 +1,37 @@
>> >> > > > +// SPDX-License-Identifier: GPL-2.0
>> >> > > > +
>> >> > > > +/*
>> >> > > > + * (C) Copyright 2023 Linaro Ltd. <maxim.uvarov@linaro.org>
>> >> > > > + */
>> >> > > > +
>> >> > > > +#include "lwip/opt.h"
>> >> > > > +#include "lwip/ip_addr.h"
>> >> > > > +#include "ping.h"
>> >> > > > +#include "lwip_ping.h"
>> >> > > > +
>> >> > > > +static ip_addr_t ip_target;
>> >> > > > +
>> >> > > > +static int ulwip_ping_tmo(void)
>> >> > > > +{
>> >> > > > +
>> >> > > > +     log_err("ping failed; host %s is not alive\n",
>> >> > > ipaddr_ntoa(&ip_target));
>> >> > > > +     return 1;
>> >> > > > +}
>> >> > > > +
>> >> > > > +int ulwip_ping(char *ping_addr)
>> >> > > > +{
>> >> > > > +     int err;
>> >> > > > +
>> >> > > > +     err = ipaddr_aton(ping_addr, &ip_target);
>> >> > > > +     if (!err) {
>> >> > > > +             log_err("wrong ping addr string \"%s\" \n", 
>> >> > > > ping_addr);
>> >> > >
>> >> > > Invalid ip address is enough
>> >> > >
>> >> > > > +             return -1;
>> >> > > > +     }
>> >> > > > +
>> >> > > > +     ulwip_set_tmo(ulwip_ping_tmo);
>> >> > > > +
>> >> > > > +     ping_init(&ip_target);
>> >> > > > +     ping_send_now();
>> >> > > > +
>> >> > > > +     return 0;
>> >> > > > +}
>> >> > > > diff --git a/net/lwip/apps/ping/lwip_ping.h
>> >> > > b/net/lwip/apps/ping/lwip_ping.h
>> >> > > > new file mode 100644
>> >> > > > index 0000000000..0374f07d9e
>> >> > > > --- /dev/null
>> >> > > > +++ b/net/lwip/apps/ping/lwip_ping.h
>> >> > > > @@ -0,0 +1,15 @@
>> >> > > > +/* SPDX-License-Identifier: GPL-2.0+ */
>> >> > > > +
>> >> > > > +/*
>> >> > > > + * (C) Copyright 2023 Linaro Ltd. <maxim.uvarov@linaro.org>
>> >> > > > + */
>> >> > > > +
>> >> > > > +#ifndef LWIP_PING_H
>> >> > > > +#define LWIP_PING_H
>> >> > > > +
>> >> > > > +#include <lwip/ip_addr.h>
>> >> > > > +
>> >> > > > +void ping_raw_init(void);
>> >> > > > +void ping_send_now(void);
>> >> > > > +
>> >> > > > +#endif /* LWIP_PING_H */
>> >> > > > diff --git a/net/lwip/apps/ping/ping.h b/net/lwip/apps/ping/ping.h
>> >> > > > new file mode 100644
>> >> > > > index 0000000000..006a18c658
>> >> > > > --- /dev/null
>> >> > > > +++ b/net/lwip/apps/ping/ping.h
>> >> > > > @@ -0,0 +1,19 @@
>> >> > > > +/* SPDX-License-Identifier: GPL-2.0 */
>> >> > > > +
>> >> > > > +#include <net/ulwip.h>
>> >> > > > +#include "lwip/ip_addr.h"
>> >> > > > +
>> >> > > > +#define LWIP_DEBUG 1 /* ping_time is under ifdef*/
>> >> > > > +#define PING_RESULT(cond) { \
>> >> > > > +     if (cond == 1) { \
>> >> > > > +             printf("host %s a alive\n", ipaddr_ntoa(addr)); \
>> >> > > > +             printf(" %"U32_F" ms\n", (sys_now() - ping_time)); \
>> >> > > > +             ulwip_exit(0); \
>> >> > > > +     } else { \
>> >> > > > +             printf("ping failed; host %s in not alive\n",\
>> >> > > > +                    ipaddr_ntoa(addr)); \
>> >> > > > +             ulwip_exit(-1); \
>> >> > > > +     } \
>> >> > > > +     } while (0);
>> >> > >
>> >> > > On the previous patch you are defining a function to do something 
>> >> > > similar
>> >> > > (httpc_result()).  We need to be consistent on this.  Can we define a
>> >> > > common function for all failures?  Certianly don't define a macro 
>> >> > > here and
>> >> > > a function elsewhere
>> >> > >
>> >> >
>> >> > Ilias, there I reuse lwip example ping.c. It has PING_RESULT which can 
>> >> > be
>> >> > redefined by the application.
>> >> > This is a way to not modify this original ping.c example code.
>> >> > The common part of this function and httpc_result() is ulwip_exit(err) 
>> >> > with
>> >> > some additional print (print is differ).
>> >>
>> >> I'll reply on this patch, although it is a general comment.
>> >>
>> >> I would like to see if we can use the cyclic feature to allow network
>> >> operations to happen in the background. This would involve splitting
>> >> each operation into:
>> >>
>> >> - setup start and kick off, e.g. ping_sttart()
>> >> - checking what needs doing, e.g. ping_poll()
>> >> - finish and clean-up, e.g. ping_finish()
>> >>
>> >> So something like:
>> >>
>> >> ping -B 1.2.3.4
>> >>
>> >> (-B is background)
>> >>
>> >> That would fire off the packet but immediately return with a prompt.
>> >> When the pings are received they would show on the console, with a new
>> >> prompt displayed. The same for tftp -B...it would start the transfer
>> >> but allow other commands to be sent while it is in progress.
>> >>
>> >> Part of the reason for this is that when booting there are a lot of
>> >> operations which take a long time and nothing happens until everything
>> >> is done. For example, with standard boot, mmc devices can be shown
>> >> right away, but USB and network ones take a lot longer, so having OS's
>> >> on those devices appear later on the slower devices is desirable for
>> >> the user.
>> >>
>> >> Is this something that lwip can support? It is one reason why I have
>> >> advocating putting the state in a struct instead of having a lot of
>> >> separate vars.
>> >>
>> >> Regards,
>> >> Simon
>> >
>> >
>> > This functionality can be added. I do not see any restrictions 
>> > implementing that.
>> > Added I mean to U-Boot. lwip will definitely work with it.
>> >
>> > There is no specific poll() for application. Application just do init() 
>> > and request
>> > the needed packets (port, type etc, like sockets) and then common lwip 
>> > poll()
>> > function is called.
>> >
>> > To implement background we need to periodically call eth_rx() and 
>> > ulwip_poll() to feed lwip
>> > stack with rx packets when we are in the cmd shell. I see in some places 
>> > we call schedule()
>> > to reprogram wdt, if we call rx polling loop in the similar way the app 
>> > will work in the background.
>> >
>> > We might also want to support 2 applications at the same time. Like a 
>> > telnet server
>> > and ping. Multiply applications also work with lwip.
>> >
>> > Even parallel download can save some time:
>> > wget -B http://url1/zImage
>> > wget -B http//url2/dtb
>> > (-B = background)
>> >
>> > But I'm thinking if we can implement background  in a more generic way in 
>> > U-Boot cmd. Things like
>> > mount UBI fs, or download from SPI flash is slow. Or probably we can also 
>> > do some loading while
>> > verifying the zImage checksum.
>>
>> Yes, perhaps we can keep a record of the command that is running, with a 
>> little bit of state there. But does the stack support two wgets at once?
>>
>> Regards,
>> Simon
>
>
> Yes, it's a complete stack and it supports multiple networking applications.

Really what I meant was whether it can support several operations at
once, based on how you have integrated it into U-Boot, but I suspect
the answer is yes.

Regards,
Simon