fping not working on Synology DiskStation.

[bolemo]

Tried from Entware, and compiling myself.

It installs, I can change permissions for setuid, but only fping -h returns something. Anything else returns nothing (and return code 4), even fping -v

root@Mnemosyne:~# ls -l /usr/local/sbin/fping 
-rwsr-xr-x 1 root root 115240 Sep  3 18:19 /usr/local/sbin/fping
root@Mnemosyne:~# file /usr/local/sbin/fping 
/usr/local/sbin/fping: setuid ELF 32-bit LSB executable, ARM, EABI5 version 1 (SYSV), dynamically linked, interpreter /opt/lib/ld-linux.so.3, for GNU/Linux 2.6.32, with debug_info, not stripped
root@Mnemosyne:~# fping -v
root@Mnemosyne:~# echo $?
4
root@Mnemosyne:~# uname -a
Linux Mnemosyne 3.2.40 #25426 SMP Wed Jul 8 03:10:10 CST 2020 armv7l GNU/Linux synology_comcerto2k_ds414j

[Kiskae]

I've run into this issue while running a newer version of the debian docker container. After looking at the system calls it appears to be caused by the absence of the /etc/protocols file causing the getprotobyname library call to fail.

While the code does include a message for this problem the error happens before the options are parsed and verbose_flag can be set, so the message never gets printed to stderr.

Considering crash_and_burn only happens in during an error it might be a good idea to remove the verbose_flag condition and always print the error. @schweikert

[georg-nielsen]

Hi, Don't know if you have already solved this issue but I ran into the same and the solution was following when building fping from source. Disable IPv6 and enable IPv4: ./configure --disable-ipv6 --enable-ipv4 --prefix=/opt and then make and make install

Best regards, Georg.

[schweikert]

We should implement a better failure mode when this happens, i.e. output an error when getprotobyname fails. Anybody willing to create a pull request?

[shaferandrew]

I was experiencing this issue on an ASUSTOR AS6604 NAS with fping 5.0-1 installed via entware.

I fixed it by copying the /etc/protocols file from an Ubuntu 21.10 machine to the NAS /etc/protocols file. The Ubuntu file was significantly longer and had more entries, specifically for IPv6 protocols.

fping responded correctly after that.

[auerswal]

Hi,

from a cursory glance at the code I think moving verbose_flag = 1; from line 496 to line 465 in fping.c might suffice to make the error message visible. E.g., see the following completely untested (not even compile tested) patch:

diff --git a/src/fping.c b/src/fping.c
index af16061..054c665 100644
--- a/src/fping.c
+++ b/src/fping.c
@@ -463,6 +463,9 @@ int main(int argc, char** argv)
         usage(0);
     }
 
+    /* enable error messages during socket creation */
+    verbose_flag = 1;
+
     socket4 = open_ping_socket_ipv4(&socktype4);
 #ifdef __linux__
     /* We only treat SOCK_DGRAM differently on Linux, where the IPv4 header
@@ -493,7 +496,6 @@ int main(int argc, char** argv)
 
     optparse_init(&optparse_state, argv);
     ident4 = ident6 = htons(getpid() & 0xFFFF);
-    verbose_flag = 1;
     backoff_flag = 1;
     opterr = 1;