Several fixes to rt_setgate(), that fix problems with route changing:
- Rearrange code so that in a case of failure the affected
route is not changed. Otherwise, a bogus rtentry will be
left and later rt_check() can recurse on its lock. [1]
- Remove comment about protocol cloning.
- Fix two places where rtentry mutex was recursed on, because
accessed via two different pointers, that were actually pointing
to the same rtentry in some cases. [1]
- Return EADDRINUSE instead of bogus EDQUOT, in case when gateway
uses the same route. [2]
Reported & tested by: ps, Andrej Zverev <az inec.ru> [1]
PR: kern/64090 [2]
Approved by: re (scottl)
eea24f1858