checksum: introduce functions to compute the header part checksum for TCP/UDP

The TCP and UDP checksums are computed using the data in the TCP/UDP
payload but also some informations in the IP header (protocol,
length, source and destination addresses).

We add two functions, proto_ipv4_header_psum() and
proto_ipv6_header_psum(), to compute the checksum of the IP
header part.

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Message-ID: <20240303135114.1023026-8-lvivier@redhat.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/checksum.h b/checksum.h
index 996f456..0f39676 100644
--- a/checksum.h
+++ b/checksum.h
@@ -15,10 +15,15 @@ uint16_t csum_fold(uint32_t sum);
 uint16_t csum_unaligned(const void *buf, size_t len, uint32_t init);
 uint16_t csum_ip4_header(uint16_t tot_len, uint8_t protocol,
 			 struct in_addr saddr, struct in_addr daddr);
+uint32_t proto_ipv4_header_psum(uint16_t tot_len, uint8_t protocol,
+				struct in_addr saddr, struct in_addr daddr);
 void csum_udp4(struct udphdr *udp4hr,
 	       struct in_addr saddr, struct in_addr daddr,
 	       const void *payload, size_t len);
 void csum_icmp4(struct icmphdr *icmp4hr, const void *payload, size_t len);
+uint32_t proto_ipv6_header_psum(uint16_t payload_len, uint8_t protocol,
+				const struct in6_addr *saddr,
+				const struct in6_addr *daddr);
 void csum_udp6(struct udphdr *udp6hr,
 	       const struct in6_addr *saddr, const struct in6_addr *daddr,
 	       const void *payload, size_t len);