Daniel was tracking down what appeared to be a networking problem….
- server reported 113 (No route to host)
- However, an strace did not reveal the networking stack ever returning that.
- On the other side, IP packets were actually received.
- When confronted with mysteries like this, I get suspicious – mainly of (fellow) programmers.
- I suggested a grep through the source code, which revealed return -EHOSTUNREACH;
- Mystery solved, which allowed us to find what was actually going on.
Lessons:
- Don’t just believe or presume the supposed origin of an error.
- Programmers often take shortcuts that cause grief later. I fully appreciate how the above code came about, but I still think it was wrong. Mapping a “similar” situation onto an existing …