ip4_header_set_len_w_chksum (ip4_header_t * ip4, u16 len)
{
ip_csum_t sum = ip4->checksum;
ip4_header_set_len_w_chksum (ip4_header_t * ip4, u16 len)
{
ip_csum_t sum = ip4->checksum;
sum = ip_csum_update (sum, old, new, ip4_header_t, length);
ip4->checksum = ip_csum_fold (sum);
sum = ip_csum_update (sum, old, new, ip4_header_t, length);
ip4->checksum = ip_csum_fold (sum);