netsfhdr
struct netsfhdr *hdr;
hdr = (struct netsfhdr *)((u8 *)th + sizeof(*th));
hdr = (struct netsfhdr *)((u8 *)uh + sizeof(*uh));
sizeof(struct netsfhdr))
struct netsfhdr *shdr;
shdr = (struct netsfhdr *)((u8 *)thdr + sizeof(*thdr));
shdr = (struct netsfhdr *)((u8 *)uhdr + sizeof(*uhdr));
struct netsfhdr *shdr;