MFp4 bz_ipv6_fast:

  Introduce a (for now copied stripped down) in6_cksum_pseudo()
  function.  We should be able to use this from in6_cksum() but
  we should also ponder possible MD specific improvements.
  It takes an extra csum argument to allow for easy checks as
  will be done by the upper layer protocol input paths.

  Sponsored by:	The FreeBSD Foundation
  Sponsored by:	iXsystems

Reviewed by:	gnn (as part of the whole)
MFC After:	3 days

1 files changed, 60 insertions, 0 deletions

diff --git a/sys/netinet6/in6_cksum.c b/sys/netinet6/in6_cksum.c
index 034848b..da8a2e6 100644
--- a/sys/netinet6/in6_cksum.c
+++ b/sys/netinet6/in6_cksum.c
@@ -80,6 +80,66 @@ __FBSDID("$FreeBSD$");
 #define ADDCARRY(x)  (x > 65535 ? x -= 65535 : x)
 #define REDUCE {l_util.l = sum; sum = l_util.s[0] + l_util.s[1]; (void)ADDCARRY(sum);}
 
+static int
+_in6_cksum_pseudo(struct ip6_hdr *ip6, uint32_t len, uint8_t nxt, uint16_t csum)
+{
+	int sum;
+	uint16_t scope, *w;
+	union {
+		u_int16_t phs[4];
+		struct {
+			u_int32_t	ph_len;
+			u_int8_t	ph_zero[3];
+			u_int8_t	ph_nxt;
+		} __packed ph;
+	} uph;
+
+	sum = csum;
+
+	/*
+	 * First create IP6 pseudo header and calculate a summary.
+	 */
+	uph.ph.ph_len = htonl(len);
+	uph.ph.ph_zero[0] = uph.ph.ph_zero[1] = uph.ph.ph_zero[2] = 0;
+	uph.ph.ph_nxt = nxt;
+
+	/* Payload length and upper layer identifier. */
+	sum += uph.phs[0];  sum += uph.phs[1];
+	sum += uph.phs[2];  sum += uph.phs[3];
+
+	/* IPv6 source address. */
+	scope = in6_getscope(&ip6->ip6_src);
+	w = (u_int16_t *)&ip6->ip6_src;
+	sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
+	sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
+	if (scope != 0)
+		sum -= scope;
+
+	/* IPv6 destination address. */
+	scope = in6_getscope(&ip6->ip6_dst);
+	w = (u_int16_t *)&ip6->ip6_dst;
+	sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
+	sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
+	if (scope != 0)
+		sum -= scope;
+
+	return (sum);
+}
+
+int
+in6_cksum_pseudo(struct ip6_hdr *ip6, uint32_t len, uint8_t nxt, uint16_t csum)
+{
+	int sum;
+	union {
+		u_int16_t s[2];
+		u_int32_t l;
+	} l_util;
+
+	sum = _in6_cksum_pseudo(ip6, len, nxt, csum);
+	REDUCE;
+	return (sum);
+}
+
 /*
  * m MUST contain a contiguous IP6 header.
  * off is an offset where TCP/UDP/ICMP6 header starts.