Package: network-manager Version: 0.9.4.0-1 Severity: wishlist Tags: upstream ipv6
When the RDNSS info in a RA expires, N-M flaps the link and causes loss of connectivity for *both* IPv4 and IPv6 (IPv6 only would be bad enough). >From /var/log/daemon.log: Apr 14 20:41:50 apu NetworkManager[1364]: <debug> [1334428910.668907] [nm-ip6-manager.c:277] rdnss_expired(): (wlan0): IPv6 RDNSS information expired Apr 14 20:41:50 apu NetworkManager[1364]: <debug> [1334428910.668996] [nm-ip6-manager.c:312] set_rdnss_timeout(): (wlan0): removing expired RA-provided nameserver 2001:db8:2001::2:53 Apr 14 20:41:50 apu NetworkManager[1364]: <debug> [1334428910.938763] [nm-system.c:1168] nm_sy stem_iface_flush_routes(): (wlan0): flushing routes ifindex 3 family UNSPEC (0) Apr 14 20:41:51 apu NetworkManager[1364]: <debug> [1334428911.86512] [nm-netlink-utils.c:360] dump_route(): route idx 1 family INET6 (10) addr 0:0:4100::2f6f:7267/0 Apr 14 20:41:51 apu NetworkManager[1364]: <debug> [1334428911.86580] [nm-netlink-utils.c:360] dump_route(): route idx 1 family INET6 (10) addr ::1/128 Apr 14 20:41:51 apu NetworkManager[1364]: <debug> [1334428911.86613] [nm-netlink-utils.c:360] dump_route(): route idx 1 family INET6 (10) addr 0:0:5100::/0 Apr 14 20:41:51 apu NetworkManager[1364]: <debug> [1334428911.87811] [nm-system.c:196] sync_addresses(): (wlan0): syncing addresses (family 0) Apr 14 20:41:51 apu NetworkManager[1364]: <debug> [1334428911.87916] [nm-system.c:249] sync_addresses(): (wlan0): removing address '192.168.1.138/24' Apr 14 20:41:51 apu wpa_supplicant[1384]: CTRL-EVENT-DISCONNECTED bssid=00:00:00:00:00:00 reason=3 Apr 14 20:41:54 apu wpa_supplicant[1384]: Trying to authenticate with 00:18:f8:f2:08:ac (SSID='boork-boork' freq=2462 MHz) Apr 14 20:41:54 apu wpa_supplicant[1384]: Trying to associate with 00:18:f8:f2:08:ac (SSID='bo ork-boork' freq=2462 MHz) Apr 14 20:41:54 apu wpa_supplicant[1384]: Associated with 00:18:f8:f2:08:ac Apr 14 20:41:54 apu wpa_supplicant[1384]: WPA: Key negotiation completed with 00:18:f8:f2:08:ac [PTK=CCMP GTK=CCMP] Apr 14 20:41:54 apu wpa_supplicant[1384]: CTRL-EVENT-CONNECTED - Connection to 00:18:f8:f2:08:ac completed (reauth) [id=0 id_str=] End of /var/log/daemon.log I would like to propose a change in the behaviour whenever a RDNSS entry expires to circumvent this unneccesary link flap. The change can be done two ways, which both can be implemented at the same time. Alternative 1: In the RDNSS RFC (6106) in the description of the RDNSS option (section 5.1) and specifically the Lifetime field it written: "Hosts MAY send a Router Solicitation to ensure the RDNSS information is fresh before the interval expires.". I think this is a very polite way to handle expiring RDNSS entries. Alternative 2: When experimenting setting different lifetimes on the RDNSS entry, I noticed that when changing it from non-nero to zero (0) the RDNSS entry where removed from /etc/resolv.conf but the link didn't flap. I'm suggesting to change the behaviour of an expired lifetime to mimic the one when changed to zero. This change is inline with the procedure in RFC6106 (section 6.2): Step (b): "If the RDNSS address already exists in the DNS Server List and the RDNSS option's Lifetime field is set to zero, delete the corresponding RDNSS entry from both the DNS Server List and the Resolver Repository..." and "The handling of expired RDNSSes is as follows: Whenever an entry expires in the DNS Server List, the expired entry is deleted from the DNS Server List, and also the RDNSS address corresponding to the entry is deleted from the Resolver Repository." Background: I've tried to diagnose link flaps on my wireless home network some time now. There havn't been any issues with the connectivity on other platforms (Android, iPhone, Win7) or when disabling IPv6 (ignore in N-M). After enabling debugging og N-M, done wireshark traces, and seen the expiring RDNSS entries I've concluded this is (most likely) is caused by lost RA's. On some occurances the received RA's have been almost 1000s apart. As I did follow the recomendation in the RFC and set the lifetime value just between MaxRtrAdvInterval and 2*MaxRtrAdvInterval, 900s that is, I now know why the RDNSS expired. As a workaround, I've set the lifetime to 1200s and haven't had a single link flap since. Nevertheless, if the procedure is changed in N-M those problems would most likely been circumvented. In a wireless environment a RA can easily be lost and that shouldn't result in a link flap causing lost connectivity for both IPv4 and IPv6. -- System Information: Debian Release: wheezy/sid APT prefers testing APT policy: (600, 'testing'), (400, 'unstable') Architecture: amd64 (x86_64) Kernel: Linux 3.2.0-2-amd64 (SMP w/4 CPU cores) Locale: LANG=en_US.utf8, LC_CTYPE=en_US.utf8 (charmap=UTF-8) Shell: /bin/sh linked to /bin/dash Versions of packages network-manager depends on: ii adduser 3.113+nmu1 ii dbus 1.5.12-1 ii dpkg 1.16.2 ii isc-dhcp-client 4.2.2.dfsg.1-4 ii libc6 2.13-27 ii libdbus-1-3 1.5.12-1 ii libdbus-glib-1-2 0.98-1 ii libgcrypt11 1.5.0-3 ii libglib2.0-0 2.30.2-6 ii libgnutls26 2.12.18-1 ii libgudev-1.0-0 175-3.1 ii libnl-3-200 3.2.7-2 ii libnl-genl-3-200 3.2.7-2 ii libnl-route-3-200 3.2.7-2 ii libnm-glib4 0.9.4.0-1 ii libnm-util2 0.9.4.0-1 ii libpolkit-gobject-1-0 0.104-2 ii libuuid1 2.20.1-4 ii lsb-base 4.1+Debian0 ii udev 175-3.1 ii wpasupplicant 0.7.3-6 Versions of packages network-manager recommends: ii crda 1.1.2-1 ii dnsmasq-base 2.60-2 ii iptables 1.4.12.2-1 ii modemmanager 0.5.2.0-1 ii policykit-1 0.104-2 ii ppp 2.4.5-5 Versions of packages network-manager suggests: ii avahi-autoipd 0.6.31-1 -- Configuration Files: /etc/NetworkManager/NetworkManager.conf changed: [main] plugins=ifupdown,keyfile [ifupdown] managed=true [logging] level=debug domains=IP6 -- no debconf information -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". 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