On Wed, 27 May 2020 22:41:27 +0800
guohongzhi <guohongz...@huawei.com> wrote:
> + /* For Udp, if the computed checksum is zero,
> + * it is transmitted as all ones.RFC768
> + */
> + if (cksum == 0 && ipv4_hdr->next_proto_id == IPPROTO_UDP)
> cksum = 0xffff;
>
The comment should be reformatted to be clearer.
Maybe:
/*
* Per RFC768:
* If the computed checksum is zero,it is transmitted as all ones
* (the equivalent in one's complement arithmetic).
*/
There is no special case required here, it is true for TCP as well.
In TCP it appears 0 is allowed but not generally used. Most implementations
use common checksum for both TCP and UDP
