On Sun, Jun 26, 2016 at 6:13 PM, 严海双 <yanhaishu...@cmss.chinamobile.com> wrote: > >> On Jun 26, 2016, at 8:35 PM, zhuyj <zyjzyj2...@gmail.com> wrote: >> >> + if (geneve->remote.sa.sa_family == AF_INET) >> + max_mtu -= sizeof(struct iphdr); >> + else >> + max_mtu -= sizeof(struct ipv6hdr); >> >> Sorry, if sa_family is not AF_NET, it is AF_INET6? >> >> There is a lot of macros in include/linux/socket.h. >> >> Zhu Yanjun >> > > There are only two enumerations AF_INET and AF_INET6 have been assigned in > geneve_newlink:
There's actually a third possibility: AF_UNSPEC, which is the default if neither remote type is specified. This is used by lightweight tunnels and should be able to work with either IPv4/v6. For the purposes of the MTU calculation this means that the IPv4 header size should be used to avoid disallowing potentially valid configurations.
