From f3378d78b5d0bc06ce577390d250d05225f9c875 Mon Sep 17 00:00:00 2001
From: jan <jan@openbsd.org>
Date: Thu, 1 Jun 2023 09:05:33 +0000
Subject: [PATCH] Enable forwarding of ix(4) LRO Pakets via TSO

Also fix ip6_forwarding of TSO packets with tcp_if_output_tso().

With a lot of testing from Hrvoje Popovski
and a lot of tweaks from bluhm@

ok bluhm@
---
 sys/dev/pci/if_ix.c        | 44 +++++++++++++++++++++++++++++++-------
 sys/netinet6/ip6_forward.c | 13 ++++++++---
 2 files changed, 46 insertions(+), 11 deletions(-)

diff --git a/sys/dev/pci/if_ix.c b/sys/dev/pci/if_ix.c
index 98815b51d62..b250ee48df8 100644
--- a/sys/dev/pci/if_ix.c
+++ b/sys/dev/pci/if_ix.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_ix.c,v 1.196 2023/05/23 09:16:16 jan Exp $	*/
+/*	$OpenBSD: if_ix.c,v 1.197 2023/06/01 09:05:33 jan Exp $	*/
 
 /******************************************************************************
 
@@ -3245,6 +3245,8 @@ ixgbe_rxeof(struct rx_ring *rxr)
 			sendmp = NULL;
 			mp->m_next = nxbuf->buf;
 		} else { /* Sending this frame? */
+			uint16_t pkts;
+
 			ixgbe_rx_checksum(staterr, sendmp);
 
 			if (hashtype != IXGBE_RXDADV_RSSTYPE_NONE) {
@@ -3252,19 +3254,45 @@ ixgbe_rxeof(struct rx_ring *rxr)
 				SET(sendmp->m_pkthdr.csum_flags, M_FLOWID);
 			}
 
-			if (sendmp->m_pkthdr.ph_mss == 1)
-				sendmp->m_pkthdr.ph_mss = 0;
+			pkts = sendmp->m_pkthdr.ph_mss;
+			sendmp->m_pkthdr.ph_mss = 0;
 
-			if (sendmp->m_pkthdr.ph_mss > 0) {
+			if (pkts > 1) {
 				struct ether_extracted ext;
-				uint16_t pkts = sendmp->m_pkthdr.ph_mss;
+				uint32_t hdrlen, paylen;
 
+				/* Calculate header size. */
 				ether_extract_headers(sendmp, &ext);
-				if (ext.tcp)
+				hdrlen = sizeof(*ext.eh);
+				if (ext.ip4)
+					hdrlen += ext.ip4->ip_hl << 2;
+				if (ext.ip6)
+					hdrlen += sizeof(*ext.ip6);
+				if (ext.tcp) {
+					hdrlen += ext.tcp->th_off << 2;
 					tcpstat_inc(tcps_inhwlro);
-				else
+					tcpstat_add(tcps_inpktlro, pkts);
+				} else {
 					tcpstat_inc(tcps_inbadlro);
-				tcpstat_add(tcps_inpktlro, pkts);
+				}
+
+				/*
+				 * If we gonna forward this packet, we have to
+				 * mark it as TSO, set a correct mss,
+				 * and recalculate the TCP checksum.
+				 */
+				paylen = sendmp->m_pkthdr.len - hdrlen;
+				if (ext.tcp && paylen >= pkts) {
+					SET(sendmp->m_pkthdr.csum_flags,
+					    M_TCP_TSO);
+					sendmp->m_pkthdr.ph_mss = paylen / pkts;
+				}
+				if (ext.tcp &&
+				    ISSET(sendmp->m_pkthdr.csum_flags,
+				    M_TCP_CSUM_IN_OK)) {
+					SET(sendmp->m_pkthdr.csum_flags,
+					    M_TCP_CSUM_OUT);
+				}
 			}
 
 			ml_enqueue(&ml, sendmp);
diff --git a/sys/netinet6/ip6_forward.c b/sys/netinet6/ip6_forward.c
index 56c6dd93b49..85a7e913406 100644
--- a/sys/netinet6/ip6_forward.c
+++ b/sys/netinet6/ip6_forward.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ip6_forward.c,v 1.109 2023/04/05 13:56:31 kn Exp $	*/
+/*	$OpenBSD: ip6_forward.c,v 1.110 2023/06/01 09:05:33 jan Exp $	*/
 /*	$KAME: ip6_forward.c,v 1.75 2001/06/29 12:42:13 jinmei Exp $	*/
 
 /*
@@ -63,8 +63,10 @@
 #include <netinet/ip_ah.h>
 #include <netinet/ip_esp.h>
 #include <netinet/udp.h>
-#include <netinet/tcp.h>
 #endif
+#include <netinet/tcp.h>
+#include <netinet/tcp_timer.h>
+#include <netinet/tcp_var.h>
 
 /*
  * Forward a packet.  If some error occurs return the sender
@@ -316,7 +318,11 @@ reroute:
 		goto reroute;
 	}
 #endif
-	in6_proto_cksum_out(m, ifp);
+
+	error = tcp_if_output_tso(ifp, &m, sin6tosa(sin6), rt, IFCAP_TSOv6,
+	    ifp->if_mtu);
+	if (error || m == NULL)
+		goto freecopy;
 
 	/* Check the size after pf_test to give pf a chance to refragment. */
 	if (m->m_pkthdr.len > ifp->if_mtu) {
@@ -327,6 +333,7 @@ reroute:
 		goto out;
 	}
 
+	in6_proto_cksum_out(m, ifp);
 	error = ifp->if_output(ifp, m, sin6tosa(sin6), rt);
 	if (error) {
 		ip6stat_inc(ip6s_cantforward);
-- 
2.20.1