Re: [DNG] an alternative to poettering's ifplugd
Hi Didier, On 19/3/19 12:39, Didier Kryn wrote: Le 19/03/2019 à 09:56, aitor_czr a écrit : Hi Nick, On 19/3/19 9:21, Dr. Nikolaus Klepp wrote: ... for i in /sys/class/net/eth*; do ... Thanks for your script! Interesting to know... With a short look, i seems to read the value content in the /sys/class/eth0/carrier file, set to "0" or "1". Just a reminder that using symbolic links in /sys isn't robust, as expained in https://www.kernel.org/doc/html/v4.16/admin-guide/sysfs-rules.html Here are two citations from this link. 1st citation: /It is agreed upon by the kernel developers that the Linux kernel does not provide a stable internal API. Therefore, there are aspects of the sysfs interface that may not be stable across kernel releases./ /To minimize the risk of breaking users of sysfs, which are in most cases low-level userspace applications, with a new kernel release, the users of sysfs must follow some rules to use an as-abstract-as-possible way to access this filesystem. The current udev and HAL programs already implement this and users are encouraged to plug, if possible, into the abstractions these programs provide instead of accessing sysfs directly./ I think we all agree to not follow this recommendation of linking to libudev. 2nd citation: /There is no such thing like class-, bus-, physical devices, interfaces, and such that you can rely on in userspace. Everything is just simply a “device”. Class-, bus-, physical, ... types are just kernel implementation details which should not be expected by applications that look for devices in sysfs./ There is at least one thing stable: the property of each devices are represented by files in a subdirectory in the tree below /sys/devices and this subdirectory is named after the device name, eg /sys/devices/pci:00/:00:19.0/net/eth0 Therefore, the only robust method I have found to programatically discover the device properties is to visit systematically all directories below /sys/devices until I find the proper subdirectory. My 1 cent. Didier Thanks a lot for the info !! Aitor. ___ Dng mailing list Dng@lists.dyne.org https://mailinglists.dyne.org/cgi-bin/mailman/listinfo/dng
Re: [DNG] an alternative to poettering's ifplugd
Le 19/03/2019 à 09:56, aitor_czr a écrit : Hi Nick, On 19/3/19 9:21, Dr. Nikolaus Klepp wrote: ... for i in /sys/class/net/eth*; do ... Thanks for your script! Interesting to know... With a short look, i seems to read the value content in the /sys/class/eth0/carrier file, set to "0" or "1". Just a reminder that using symbolic links in /sys isn't robust, as expained in https://www.kernel.org/doc/html/v4.16/admin-guide/sysfs-rules.html Here are two citations from this link. 1st citation: /It is agreed upon by the kernel developers that the Linux kernel does not provide a stable internal API. Therefore, there are aspects of the sysfs interface that may not be stable across kernel releases./ /To minimize the risk of breaking users of sysfs, which are in most cases low-level userspace applications, with a new kernel release, the users of sysfs must follow some rules to use an as-abstract-as-possible way to access this filesystem. The current udev and HAL programs already implement this and users are encouraged to plug, if possible, into the abstractions these programs provide instead of accessing sysfs directly./ I think we all agree to not follow this recommendation of linking to libudev. 2nd citation: /There is no such thing like class-, bus-, physical devices, interfaces, and such that you can rely on in userspace. Everything is just simply a “device”. Class-, bus-, physical, ... types are just kernel implementation details which should not be expected by applications that look for devices in sysfs./ There is at least one thing stable: the property of each devices are represented by files in a subdirectory in the tree below /sys/devices and this subdirectory is named after the device name, eg /sys/devices/pci:00/:00:19.0/net/eth0 Therefore, the only robust method I have found to programatically discover the device properties is to visit systematically all directories below /sys/devices until I find the proper subdirectory. My 1 cent. Didier ___ Dng mailing list Dng@lists.dyne.org https://mailinglists.dyne.org/cgi-bin/mailman/listinfo/dng
Re: [DNG] an alternative to poettering's ifplugd
Hi, On 19/3/19 9:21, Dr. Nikolaus Klepp wrote: You might call me ignorant, but with bash this can be done a bit simpler (this is from my solution to the detect-if-kable-present-while-booting-problem):-) The best solution might be to run the connection attempt on a secondary plane without interrupting the boot process... Aitor. ___ Dng mailing list Dng@lists.dyne.org https://mailinglists.dyne.org/cgi-bin/mailman/listinfo/dng
Re: [DNG] an alternative to poettering's ifplugd
Hi Aitor!
Anno domini 2019 Tue, 19 Mar 09:56:07 +0100
aitor_czr scripsit:
> Hi Nick,
>
> On 19/3/19 9:21, Dr. Nikolaus Klepp wrote:
> > You might call me ignorant, but with bash this can be done a bit simpler
> > (this is from my solution to the
> > detect-if-kable-present-while-booting-problem):-)
> >
> > #!/bin/bash
> >
> > while sleep 1; do
> > for i in /sys/class/net/eth*; do
> > VAR=$(basename $i)
> > VAL=$(sed -n 's/0/UN/p' $i/carrier)PLUGGED
> > if [ "${!VAR}" != "$VAL" ]; then
> > echo $VAR $VAL
> > declare $VAR=$VAL
> > fi
> > done
> > done
> >
> >
> > Nik
> Thanks for your script! Interesting to know... With a short look, i
> seems to read the value content in the /sys/class/eth0/carrier file, set
> to "0" or "1".
> I was thinking about this possibility a couple of days ago, but i'm not
> pretty sure if its value also depends on the status of the network
> hotpluggable device. I'm testing it...
Interestingly the "carrier"-column in /proc/net/dev does not correspond to the
cable beeing plugged in or not, it's always "0" on my computer.
Nik
> On the other hand, here you are the code used in the ethtool-lite.c file
> of the netcfg udeb package used by debian-installer, doing something
> similar (in the case of the FreeBSD kernel
> it uses a raw socket instead):
>
> int len = strlen(SYSCLASSNET) + strlen(iface) + strlen("/carrier") + 1;
> char* filename = malloc(len);
> snprintf(filename, len, SYSCLASSNET "%s/carrier", iface);
> FILE* fp = fopen(filename, "r");
> free(filename);
>
> char result[2];
> if (fgets(result, sizeof(result), fp) == NULL) {
> fclose(fp);
> if (errno == EINVAL) {
> di_info("ethtool-lite: %s is down", iface);
> return DISCONNECTED;
> }
> di_error("ethtool-lite: getting carrier failed: %s",
> strerror(errno));
> return UNKNOWN;
> }
> fclose(fp);
>
> switch (result[0]) {
> case '1':
> di_info("ethtool-lite: %s: carrier up", iface);
> return CONNECTED;
> case '0':
> di_info("ethtool-lite: %s: carrier down", iface);
> return DISCONNECTED;
> }
> di_info("ethtool-lite: %s: could not determine carrier state; got
> \"%s\"",
> iface, result);
> return UNKNOWN;
>
> Cheers,
>
> Aitor.
--
Please do not email me anything that you are not comfortable also sharing with
the NSA, CIA ...
___
Dng mailing list
Dng@lists.dyne.org
https://mailinglists.dyne.org/cgi-bin/mailman/listinfo/dng
Re: [DNG] an alternative to poettering's ifplugd
On 19/3/19 9:56, aitor_czr wrote:
Hi Nick,
On 19/3/19 9:21, Dr. Nikolaus Klepp wrote:
You might call me ignorant, but with bash this can be done a bit simpler (this
is from my solution to the detect-if-kable-present-while-booting-problem):-)
#!/bin/bash
while sleep 1; do
for i in /sys/class/net/eth*; do
VAR=$(basename $i)
VAL=$(sed -n 's/0/UN/p' $i/carrier)PLUGGED
if [ "${!VAR}" != "$VAL" ]; then
echo $VAR $VAL
declare $VAR=$VAL
fi
done
done
Nik
Thanks for your script! Interesting to know... With a short look, i
seems to read the value content in the /sys/class/eth0/carrier file,
set to "0" or "1".
I was thinking about this possibility a couple of days ago, but i'm
not pretty sure if its value also depends on the status of the network
hotpluggable device. I'm testing it...
On the other hand, here you are the code used in the ethtool-lite.c
file of the netcfg udeb package used by debian-installer, doing
something similar (in the case of the FreeBSD kernel
it uses a raw socket instead):
int len = strlen(SYSCLASSNET) + strlen(iface) + strlen("/carrier")
+ 1;
char* filename = malloc(len);
snprintf(filename, len, SYSCLASSNET "%s/carrier", iface);
FILE* fp = fopen(filename, "r");
free(filename);
char result[2];
if (fgets(result, sizeof(result), fp) == NULL) {
fclose(fp);
if (errno == EINVAL) {
di_info("ethtool-lite: %s is down", iface);
return DISCONNECTED;
}
di_error("ethtool-lite: getting carrier failed: %s",
strerror(errno));
return UNKNOWN;
}
fclose(fp);
switch (result[0]) {
case '1':
di_info("ethtool-lite: %s: carrier up", iface);
return CONNECTED;
case '0':
di_info("ethtool-lite: %s: carrier down", iface);
return DISCONNECTED;
}
di_info("ethtool-lite: %s: could not determine carrier state; got
\"%s\"",
iface, result);
return UNKNOWN;
Cheers,
#if defined(__linux__)
/* The above code */
#elif defined(__FreeBSD_kernel__)
int fd = socket(AF_INET, SOCK_DGRAM, 0);
if (fd < 0)
{
di_warning("ethtool-lite: could not open control socket\n");
return UNKNOWN;
}
___
Dng mailing list
Dng@lists.dyne.org
https://mailinglists.dyne.org/cgi-bin/mailman/listinfo/dng
Re: [DNG] an alternative to poettering's ifplugd
Hi Nick,
On 19/3/19 9:21, Dr. Nikolaus Klepp wrote:
You might call me ignorant, but with bash this can be done a bit simpler (this
is from my solution to the detect-if-kable-present-while-booting-problem):-)
#!/bin/bash
while sleep 1; do
for i in /sys/class/net/eth*; do
VAR=$(basename $i)
VAL=$(sed -n 's/0/UN/p' $i/carrier)PLUGGED
if [ "${!VAR}" != "$VAL" ]; then
echo $VAR $VAL
declare $VAR=$VAL
fi
done
done
Nik
Thanks for your script! Interesting to know... With a short look, i
seems to read the value content in the /sys/class/eth0/carrier file, set
to "0" or "1".
I was thinking about this possibility a couple of days ago, but i'm not
pretty sure if its value also depends on the status of the network
hotpluggable device. I'm testing it...
On the other hand, here you are the code used in the ethtool-lite.c file
of the netcfg udeb package used by debian-installer, doing something
similar (in the case of the FreeBSD kernel
it uses a raw socket instead):
int len = strlen(SYSCLASSNET) + strlen(iface) + strlen("/carrier") + 1;
char* filename = malloc(len);
snprintf(filename, len, SYSCLASSNET "%s/carrier", iface);
FILE* fp = fopen(filename, "r");
free(filename);
char result[2];
if (fgets(result, sizeof(result), fp) == NULL) {
fclose(fp);
if (errno == EINVAL) {
di_info("ethtool-lite: %s is down", iface);
return DISCONNECTED;
}
di_error("ethtool-lite: getting carrier failed: %s",
strerror(errno));
return UNKNOWN;
}
fclose(fp);
switch (result[0]) {
case '1':
di_info("ethtool-lite: %s: carrier up", iface);
return CONNECTED;
case '0':
di_info("ethtool-lite: %s: carrier down", iface);
return DISCONNECTED;
}
di_info("ethtool-lite: %s: could not determine carrier state; got
\"%s\"",
iface, result);
return UNKNOWN;
Cheers,
Aitor.
___
Dng mailing list
Dng@lists.dyne.org
https://mailinglists.dyne.org/cgi-bin/mailman/listinfo/dng
Re: [DNG] an alternative to poettering's ifplugd
Hi!
Anno domini 2019 Mon, 18 Mar 18:37:37 +0100
aitor_czr scripsit:
> Hi all,
>
> On 17/3/19 13:45, aitor_czr wrote:
> >
> > I'm also working on an alternative to poettering's ifplugd for the
> > automatically wired connect option of simple-netaid.
> >
> > Aitor.
> >
> Here you are the code:
>
> gnuinos.org/examples/netproc/main.c
>
> Install the libiw-dev and ethtool packages, and build the file:
>
> gcc main.c -liw -o main
>
> and run it in the command line:
>
> $ ./main
>
> The output will be:
>
> The wire is PLUGGED/UNPLUGGED
>
> The unplug event is detected inmediatly, but the unplug event takes a
> few seconds. It's working for me.
>
> I need testers.
>
> Thanks in advance :)
>
> Aitor.
>
>
>
>
You might call me ignorant, but with bash this can be done a bit simpler (this
is from my solution to the detect-if-kable-present-while-booting-problem) :-)
#!/bin/bash
while sleep 1; do
for i in /sys/class/net/eth*; do
VAR=$(basename $i)
VAL=$(sed -n 's/0/UN/p' $i/carrier)PLUGGED
if [ "${!VAR}" != "$VAL" ]; then
echo $VAR $VAL
declare $VAR=$VAL
fi
done
done
Nik
--
Please do not email me anything that you are not comfortable also sharing with
the NSA, CIA ...
___
Dng mailing list
Dng@lists.dyne.org
https://mailinglists.dyne.org/cgi-bin/mailman/listinfo/dng
Re: [DNG] an alternative to poettering's ifplugd
Hi, On 18/3/19 18:37, aitor_czr wrote: Hi all, On 17/3/19 13:45, aitor_czr wrote: I'm also working on an alternative to poettering's ifplugd for the automatically wired connect option of simple-netaid. Aitor. Here you are the code: gnuinos.org/examples/netproc/main.c Install the libiw-dev and ethtool packages, and build the file: gcc main.c -liw -o main and run it in the command line: $ ./main The output will be: The wire is PLUGGED/UNPLUGGED The unplug event is detected inmediatly, but the unplug event takes a few seconds. It's working for me. I need testers. Thanks in advance :) Aitor. The ethtool dependency is superfluous, i removed the header and updated the sources in the link: http://www.gnuinos.org/examples/netproc/ Cheers, Aitor. ___ Dng mailing list Dng@lists.dyne.org https://mailinglists.dyne.org/cgi-bin/mailman/listinfo/dng
Re: [DNG] an alternative to poettering's ifplugd
Hi all, On 17/3/19 13:45, aitor_czr wrote: I'm also working on an alternative to poettering's ifplugd for the automatically wired connect option of simple-netaid. Aitor. Here you are the code: gnuinos.org/examples/netproc/main.c Install the libiw-dev and ethtool packages, and build the file: gcc main.c -liw -o main and run it in the command line: $ ./main The output will be: The wire is PLUGGED/UNPLUGGED The unplug event is detected inmediatly, but the unplug event takes a few seconds. It's working for me. I need testers. Thanks in advance :) Aitor. ___ Dng mailing list Dng@lists.dyne.org https://mailinglists.dyne.org/cgi-bin/mailman/listinfo/dng
