在 2017/7/12 12:55, Ben Pfaff 写道:
> On Tue, Jul 04, 2017 at 08:52:57AM +0800, Haifeng Lin wrote:
>> The ifa_netmask is null when failed to call ioctl
>> in getifaddrs
>>
>> Signed-off-by: Haifeng Lin <[email protected]>
> Thanks for figuring this out.
>
> What does it mean if ifa_netmask is null? Does it mean that the address
> should be ignored entirely? The manpage for getifaddrs doesn't say.
> And what about for IPv4 addresses?
The glibc code shows that the ifa_netmask maybe NULL：
...
if (__ioctl (fd, SIOCGIFNETMASK, ifr) < 0)
storage[i].ia.ifa_netmask = NULL;
else
{
storage[i].ia.ifa_netmask = &storage[i].netmask;
storage[i].netmask = ifr->ifr_netmask;
}
...
> Maybe the right fix would be this:
>
> diff --git a/lib/netdev.c b/lib/netdev.c
> index 26e87a2ee2ec..68003a829f27 100644
> --- a/lib/netdev.c
> +++ b/lib/netdev.c
> @@ -1967,7 +1967,8 @@ netdev_get_addrs(const char dev[], struct in6_addr
> **paddr,
> for (ifa = if_addr_list; ifa; ifa = ifa->ifa_next) {
> int family;
>
> - if (strncmp(ifa->ifa_name, dev, IFNAMSIZ) || ifa->ifa_addr == NULL) {
> + if (strncmp(ifa->ifa_name, dev, IFNAMSIZ)
> + || !ifa->ifa_addr || !ifa->ifa_netmask) {
> continue;
> }
>
> What do you think?
I think we should check ifa_name too because we don't know what would happen in
glibc
and we should guarantee that ovs-vswitchd not crash.
diff --git a/lib/netdev.c b/lib/netdev.c index a7840a8..12041f9 100644 ---
a/lib/netdev.c +++ b/lib/netdev.c @@ -1942,7 +1942,7 @@ netdev_get_addrs(const
char dev[], struct in6_addr **paddr, } for (ifa = if_addr_list; ifa; ifa =
ifa->ifa_next) { - if (ifa->ifa_addr != NULL) { + if (ifa->ifa_addr &&
ifa->ifa_name) { int family; family = ifa->ifa_addr->sa_family; @@ -1963,7
+1963,8 @@ netdev_get_addrs(const char dev[], struct in6_addr **paddr, for (ifa
= if_addr_list; ifa; ifa = ifa->ifa_next) { int family; - if
(strncmp(ifa->ifa_name, dev, IFNAMSIZ) || ifa->ifa_addr == NULL) { + if
(!ifa->ifa_name || !ifa->ifa_addr || !ifa->ifa_netmask + ||
strncmp(ifa->ifa_name, dev, IFNAMSIZ)) { continue; }
> Thanks,
>
> Ben.
>
> .
>
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