From d4e54f22ff4550b27f0c2953191f65a69bdb814c Mon Sep 17 00:00:00 2001 From: Thomas Haller Date: Fri, 4 Apr 2014 16:14:46 +0200 Subject: [PATCH 1/1] platform: workaround older kernels that don't accept extended address flags via netlink Extended address flags are represented by the additional netlink attribute IFA_FLAGS. Older kernels don't know this flag and refuse the messages RTM_NEWADDR and RTMDEL_ADDR when it contains unknown attributes. See net/core/rtnetlink.c, rtnetlink_rcv_msg(). This was fixed by kernel commit 661d2967b3f1b34eeaa7e212e7b9bbe8ee072b59. libnl was fixed in commit 5206c050504f8676a24854519b9c351470fb7cc6 only to send the additional netlink attribute, when there are actually flags that make this necessary. This commit changes nm-platform to strip the flags to &= 0xFF, if we detect that the kernel does not understand extended address flags. https://bugzilla.redhat.com/show_bug.cgi?id=1063885 Signed-off-by: Thomas Haller (cherry picked from commit dac51747ab5853b00557d7d97d4b2eae05968c03) --- src/platform/nm-linux-platform.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/src/platform/nm-linux-platform.c b/src/platform/nm-linux-platform.c index b5e3618..dacdc16 100644 --- a/src/platform/nm-linux-platform.c +++ b/src/platform/nm-linux-platform.c @@ -2405,8 +2405,19 @@ build_rtnl_addr (int family, rtnl_addr_set_valid_lifetime (rtnladdr, lifetime); rtnl_addr_set_preferred_lifetime (rtnladdr, preferred); } - if (flags) + if (flags) { + if ((flags & ~0xFF) && !check_support_kernel_extended_ifa_flags (nm_platform_get ())) { + /* Older kernels don't accept unknown netlink attributes. + * + * With commit libnl commit 5206c050504f8676a24854519b9c351470fb7cc6, libnl will only set + * the extended address flags attribute IFA_FLAGS when necessary (> 8 bit). But it's up to + * us not to shove those extended flags on to older kernels. + * + * Just silently clear them. The kernel should ignore those unknown flags anyway. */ + flags &= 0xFF; + } rtnl_addr_set_flags (rtnladdr, flags); + } return (struct nl_object *) rtnladdr; } -- 1.9.0