Bug 22185
| Summary: | Identical IP addresses on two broadcast interfaces | ||
|---|---|---|---|
| Product: | Base System | Reporter: | Yar Tikhiy <yar> |
| Component: | kern | Assignee: | freebsd-bugs (Nobody) <bugs> |
| Status: | Closed FIXED | ||
| Severity: | Affects Only Me | ||
| Priority: | Normal | ||
| Version: | 4.1-STABLE | ||
| Hardware: | Any | ||
| OS: | Any | ||
<<On Sat, 21 Oct 2000 17:59:52 +0400 (MSD), yar@comp.chem.msu.su said: > Maybe, the code should try to add the link layer route first, > and assign the address to the interface only if adding > the route succeeded? This can't be done, because in order to add the route, the ifaddr must already be present. The trouble is that sometimes this error does not indicate a problem (even though it usually does). I think the right thing is probably to compare the new (A1, M1) against all the existing ifaddrs and fail the request if any (A2, M2) is present such that M1 == M2 and (A1 & M1) == (A2 & M2). There may be other conditions which should fail as well. -GAWollman -- Garrett A. Wollman | O Siem / We are all family / O Siem / We're all the same wollman@lcs.mit.edu | O Siem / The fires of freedom Opinions not those of| Dance in the burning flame MIT, LCS, CRS, or NSA| - Susan Aglukark and Chad Irschick State Changed From-To: open->closed fixed, see bin/21292 [src/sys/netinet/in.c 1.44.2.8] |
It's possible to add two absolutely identical IP addresses to two different broadcast interfaces. I guess it would be possible to add different addresses from the same network, too. The problem arises from in_control()/in_ifinit() leaving the address installed even if adding the link-layer route fails. Fix: Maybe, the code should try to add the link layer route first, and assign the address to the interface only if adding the route succeeded? How-To-Repeat: yar# ifconfig fxp0 10.1.1.1 yar# ifconfig fxp1 10.1.1.1 ifconfig: ioctl (SIOCAIFADDR): File exists yar# ifconfig fxp0 fxp0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500 inet 10.1.1.1 netmask 0xff000000 broadcast 10.255.255.255 ether 00:d0:b7:60:63:da media: autoselect (100baseTX) status: active supported media: autoselect 100baseTX <full-duplex> 100baseTX 10baseT/UT P <full-duplex> 10baseT/UTP yar# ifconfig fxp1 fxp1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500 inet 10.1.1.1 netmask 0xff000000 broadcast 10.255.255.255 ether 00:a0:c9:66:67:4d media: autoselect (100baseTX) status: active supported media: autoselect 100baseTX <full-duplex> 100baseTX 10baseT/UT P <full-duplex> 10baseT/UTP