On Tue, Dec 20, 2016 at 2:12 PM, Dave Jones <da...@codemonkey.org.uk> wrote: > fd = socket(AF_INET6, SOCK_RAW, 7); > > setsockopt(fd, SOL_IPV6, IPV6_CHECKSUM, &zero, 4); > setsockopt(fd, SOL_IPV6, IPV6_DSTOPTS, &buf, LEN); >
Interesting, you set the checksum offset to be 0, but the packet size is actually 49, transport header is located at offset 48, so apparently the packet doesn't have room for a 16bit checksum after network header. Your original patch seems reasonable to me, unless there is some check in __ip6_append_data() which is supposed to catch this, but CHECKSUM is specific to raw socket only.
