Add csum_icmp6() helper for calculating ICMPv6 checksums

At least two places in passt calculate ICMPv6 checksums, ndp() and
tap_ip_send().  Add a helper to handle this calculation in both places.
For future flexibility, the new helper takes parameters for the fields in
the IPv6 pseudo-header, so an IPv6 header or pseudo-header doesn't need to
be explicitly constructed.  It also allows the ICMPv6 header and payload to
be in separate buffers, although we don't use this yet.

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 5418406..d7daabf 100644
--- a/checksum.h
+++ b/checksum.h
@@ -6,9 +6,14 @@
 #ifndef CHECKSUM_H
 #define CHECKSUM_H
 
+struct icmp6hdr;
+
 uint32_t sum_16b(const void *buf, size_t len);
 uint16_t csum_fold(uint32_t sum);
 uint16_t csum_unaligned(const void *buf, size_t len, uint32_t init);
+void csum_icmp6(struct icmp6hdr *icmp6hr,
+		const struct in6_addr *saddr, const struct in6_addr *daddr,
+		const void *payload, size_t len);
 void csum_tcp4(struct iphdr *iph);
 uint16_t csum(const void *buf, size_t len, uint32_t init);