diff options
Diffstat (limited to 'util.c')
| -rw-r--r-- | util.c | 80 |
1 files changed, 0 insertions, 80 deletions
@@ -77,86 +77,6 @@ logfn(debug, LOG_DEBUG) #endif /** - * sum_16b() - Calculate sum of 16-bit words - * @buf: Input buffer - * @len: Buffer length - * - * Return: 32-bit sum of 16-bit words -*/ -uint32_t sum_16b(void *buf, size_t len) -{ - uint32_t sum = 0; - uint16_t *p = buf; - size_t len1 = len / 2; - size_t off; - - for (off = 0; off < len1; off++, p++) - sum += *p; - - if (len % 2) - sum += *p & 0xff; - - return sum; -} - -/** - * csum_fold() - Fold long sum for IP and TCP checksum - * @sum: Original long sum - * - * Return: 16-bit folded sum - */ -uint16_t csum_fold(uint32_t sum) -{ - while (sum >> 16) - sum = (sum & 0xffff) + (sum >> 16); - - return sum; -} - -/** - * csum_ip4() - Calculate IPv4 checksum - * @buf: Packet buffer, L3 headers - * @len: Total L3 packet length - * - * Return: 16-bit IPv4-style checksum - */ -uint16_t csum_ip4(void *buf, size_t len) -{ - return ~csum_fold(sum_16b(buf, len)); -} - -/** - * csum_tcp4() - Calculate TCP checksum for IPv4 and set in place - * @iph: Packet buffer, IP header - */ -void csum_tcp4(struct iphdr *iph) -{ - struct tcphdr *th = (struct tcphdr *)((char *)iph + iph->ihl * 4); - uint16_t tlen = ntohs(iph->tot_len) - iph->ihl * 4, *p = (uint16_t *)th; - uint32_t sum = 0; - - sum += (iph->saddr >> 16) & 0xffff; - sum += iph->saddr & 0xffff; - sum += (iph->daddr >> 16) & 0xffff; - sum += iph->daddr & 0xffff; - - sum += htons(IPPROTO_TCP); - sum += htons(tlen); - - th->check = 0; - while (tlen > 1) { - sum += *p++; - tlen -= 2; - } - - if (tlen > 0) { - sum += *p & htons(0xff00); - } - - th->check = (uint16_t)~csum_fold(sum); -} - -/** * ipv6_l4hdr() - Find pointer to L4 header in IPv6 packet and extract protocol * @ip6h: IPv6 header * @proto: Filled with L4 protocol number |