16 	int sum, oddbyte;  in compute_ip_checksum()  local
19 	sum = 0;  in compute_ip_checksum()
21 		sum += *ptr++;  in compute_ip_checksum()
28 		sum += oddbyte;  in compute_ip_checksum()
30 	sum = (sum >> 16) + (sum & 0xffff);  in compute_ip_checksum()
31 	sum += (sum >> 16);  in compute_ip_checksum()
32 	sum = ~sum & 0xffff;  in compute_ip_checksum()
34 	return sum;  in compute_ip_checksum()
37 unsigned add_ip_checksums(unsigned offset, unsigned sum, unsigned new)  in add_ip_checksums()  argument
41 	sum = ~sum & 0xffff;  in add_ip_checksums()
45 		 * byte-swap the sum if it came from an odd offset; since the  in add_ip_checksums()
50 	checksum = sum + new;  in add_ip_checksums()