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Diffstat (limited to 'checksum.c')
-rw-r--r--checksum.c67
1 files changed, 52 insertions, 15 deletions
diff --git a/checksum.c b/checksum.c
index 1ac7975..f8a7b53 100644
--- a/checksum.c
+++ b/checksum.c
@@ -138,6 +138,29 @@ uint16_t csum_ip4_header(uint16_t tot_len, uint8_t protocol,
}
/**
+ * proto_ipv4_header_psum() - Calculates the partial checksum of an
+ * IPv4 header for UDP or TCP
+ * @tot_len: IPv4 Payload length (host order)
+ * @proto: Protocol number (host order)
+ * @saddr: Source address (network order)
+ * @daddr: Destination address (network order)
+ * Returns: Partial checksum of the IPv4 header
+ */
+uint32_t proto_ipv4_header_psum(uint16_t tot_len, uint8_t protocol,
+ struct in_addr saddr, struct in_addr daddr)
+{
+ uint32_t psum = htons(protocol);
+
+ psum += (saddr.s_addr >> 16) & 0xffff;
+ psum += saddr.s_addr & 0xffff;
+ psum += (daddr.s_addr >> 16) & 0xffff;
+ psum += daddr.s_addr & 0xffff;
+ psum += htons(tot_len);
+
+ return psum;
+}
+
+/**
* csum_udp4() - Calculate and set checksum for a UDP over IPv4 packet
* @udp4hr: UDP header, initialised apart from checksum
* @saddr: IPv4 source address
@@ -153,14 +176,10 @@ void csum_udp4(struct udphdr *udp4hr,
udp4hr->check = 0;
if (UDP4_REAL_CHECKSUMS) {
- /* UNTESTED: if we did want real UDPv4 checksums, this
- * is roughly what we'd need */
- uint32_t psum = csum_fold(saddr.s_addr)
- + csum_fold(daddr.s_addr)
- + htons(len + sizeof(*udp4hr))
- + htons(IPPROTO_UDP);
- /* Add in partial checksum for the UDP header alone */
- psum += sum_16b(udp4hr, sizeof(*udp4hr));
+ uint16_t tot_len = len + sizeof(struct udphdr);
+ uint32_t psum = proto_ipv4_header_psum(tot_len, IPPROTO_UDP,
+ saddr, daddr);
+ psum = csum_unfolded(udp4hr, sizeof(struct udphdr), psum);
udp4hr->check = csum(payload, len, psum);
}
}
@@ -184,6 +203,27 @@ void csum_icmp4(struct icmphdr *icmp4hr, const void *payload, size_t len)
}
/**
+ * proto_ipv6_header_psum() - Calculates the partial checksum of an
+ * IPv6 header for UDP or TCP
+ * @payload_len: IPv6 payload length (host order)
+ * @proto: Protocol number (host order)
+ * @saddr: Source address (network order)
+ * @daddr: Destination address (network order)
+ * Returns: Partial checksum of the IPv6 header
+ */
+uint32_t proto_ipv6_header_psum(uint16_t payload_len, uint8_t protocol,
+ const struct in6_addr *saddr,
+ const struct in6_addr *daddr)
+{
+ uint32_t sum = htons(protocol) + htons(payload_len);
+
+ sum += sum_16b(saddr, sizeof(*saddr));
+ sum += sum_16b(daddr, sizeof(*daddr));
+
+ return sum;
+}
+
+/**
* csum_udp6() - Calculate and set checksum for a UDP over IPv6 packet
* @udp6hr: UDP header, initialised apart from checksum
* @payload: UDP packet payload
@@ -193,14 +233,11 @@ void csum_udp6(struct udphdr *udp6hr,
const struct in6_addr *saddr, const struct in6_addr *daddr,
const void *payload, size_t len)
{
- /* Partial checksum for the pseudo-IPv6 header */
- uint32_t psum = sum_16b(saddr, sizeof(*saddr)) +
- sum_16b(daddr, sizeof(*daddr)) +
- htons(len + sizeof(*udp6hr)) + htons(IPPROTO_UDP);
-
+ uint32_t psum = proto_ipv6_header_psum(len + sizeof(struct udphdr),
+ IPPROTO_UDP, saddr, daddr);
udp6hr->check = 0;
- /* Add in partial checksum for the UDP header alone */
- psum += sum_16b(udp6hr, sizeof(*udp6hr));
+
+ psum = csum_unfolded(udp6hr, sizeof(struct udphdr), psum);
udp6hr->check = csum(payload, len, psum);
}