Hmm
#define ipa_opposite(x) _MI(_I(x) ^ 1)
- this is correct for /31 ptp links (that are valid according to RFC 3021), but not for /30 ptp links. There should be ^ 3 ?
Yes, this is obviously wrong. Could you please try this patch? diff -u -p -r1.6 ip.c --- lib/ip.c 8 Jun 2000 12:37:21 -0000 1.6 +++ lib/ip.c 25 Aug 2008 11:19:02 -0000 @@ -153,13 +153,14 @@ int ipa_classify(ip_addr x) { DUMMY } /** * ipa_opposite - return address of point-to-point neighbor * @x: IP address of our end of the link + * @pxlen: network prefix length * * ipa_opposite() returns an address of the opposite end of a numbered * point-to-point link. * * This function is available in IPv4 version only. */ -ip_addr ipa_opposite(ip_addr x) { DUMMY } +ip_addr ipa_opposite(ip_addr x, int pxlen) { DUMMY } /** * ipa_class_mask - guess netmask according to address class diff -u -p -r1.17 ipv4.h --- lib/ipv4.h 7 Jun 2000 01:18:36 -0000 1.17 +++ lib/ipv4.h 25 Aug 2008 11:19:02 -0000 @@ -53,7 +53,7 @@ typedef u32 ip_addr; #define ipa_hton(x) x = _MI(htonl(_I(x))) #define ipa_ntoh(x) x = _MI(ntohl(_I(x))) #define ipa_classify(x) ipv4_classify(_I(x)) -#define ipa_opposite(x) _MI(_I(x) ^ 1) +#define ipa_opposite(x,len) _MI(_I(x) ^ (len == 30 ? 3 : 1)) #define ipa_class_mask(x) _MI(ipv4_class_mask(_I(x))) #define ipa_from_u32(x) _MI(x) #define ipa_to_u32(x) _I(x) diff -u -p -r1.39 netlink.c --- sysdep/linux/netlink/netlink.c 5 Jun 2004 09:58:23 -0000 1.39 +++ sysdep/linux/netlink/netlink.c 25 Aug 2008 11:19:02 -0000 @@ -377,7 +377,7 @@ nl_parse_addr(struct nlmsghdr *h) ifa.brd = ipa_or(ifa.ip, ipa_not(netmask)); #ifndef IPV6 if (i->ifa_prefixlen == BITS_PER_IP_ADDRESS - 2) - ifa.opposite = ipa_opposite(ifa.ip); + ifa.opposite = ipa_opposite(ifa.ip, i->ifa_prefixlen); if ((ifi->flags & IF_BROADCAST) && a[IFA_BROADCAST]) { memcpy(&xbrd, RTA_DATA(a[IFA_BROADCAST]), sizeof(xbrd)); diff -u -p -r1.16 krt-iface.c --- sysdep/unix/krt-iface.c 31 May 2004 13:25:00 -0000 1.16 +++ sysdep/unix/krt-iface.c 25 Aug 2008 11:19:02 -0000 @@ -140,7 +140,7 @@ scan_ifs(struct ifreq *r, int cnt) if (a.pxlen < 30) i.flags |= IF_MULTIACCESS; else - a.opposite = ipa_opposite(a.ip); + a.opposite = ipa_opposite(a.ip, a.pxlen); } else a.brd = a.opposite; Have a nice fortnight -- Martin `MJ' Mares <mj@ucw.cz> http://mj.ucw.cz/ Faculty of Math and Physics, Charles University, Prague, Czech Rep., Earth "In theory, practice and theory are the same, but in practice they are different." -- Larry McVoy