If `ipfw fwd' loops an mbuf back to ip_input from ip_output and the

mbuf is marked for delayed checksums, then additionally mark the
packet as having it's checksums computed.  This allows us to bypass
computing/checking the checksum entirely, which isn't really needeed
as the packet has never hit the wire.

Reviewed by:		green

1 files changed, 7 insertions, 6 deletions

diff --git a/sys/netinet/ip_output.c b/sys/netinet/ip_output.c
index b44765f..9a983a1 100644
--- a/sys/netinet/ip_output.c
+++ b/sys/netinet/ip_output.c
@@ -574,14 +574,15 @@ sendit:
 				ip_fw_fwd_addr = dst;
 				if (m->m_pkthdr.rcvif == NULL)
 					m->m_pkthdr.rcvif = ifunit("lo0");
+				if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
+					m->m_pkthdr.csum_flags |=
+					    CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
+					m0->m_pkthdr.csum_data = 0xffff;
+				}
+				m->m_pkthdr.csum_flags |=
+				    CSUM_IP_CHECKED | CSUM_IP_VALID;
 				ip->ip_len = htons((u_short)ip->ip_len);
 				ip->ip_off = htons((u_short)ip->ip_off);
-				ip->ip_sum = 0;
-				if (ip->ip_vhl == IP_VHL_BORING) {
-					ip->ip_sum = in_cksum_hdr(ip);
-				} else {
-					ip->ip_sum = in_cksum(m, hlen);
-				}
 				ip_input(m);
 				goto done;
 			}