From ae2705b80d4177d050950af687708c7138bb6b6e Mon Sep 17 00:00:00 2001
From: Didier Pallard <didier.pallard@6wind.com>
Date: Wed, 28 Mar 2018 17:43:47 +0200
Subject: [PATCH] net/vmxnet3: guess MSS if not provided in LRO mode

Not so old variants of vmxnet3 do not provide MSS value along with
LRO packet. When this case happens, try to guess MSS value with
information at hand.

Signed-off-by: Didier Pallard <didier.pallard@6wind.com>
Acked-by: Yong Wang <yongwang@vmware.com>
---
 drivers/net/vmxnet3/Makefile         |  1 +
 drivers/net/vmxnet3/vmxnet3_ethdev.c |  2 +
 drivers/net/vmxnet3/vmxnet3_ethdev.h |  1 +
 drivers/net/vmxnet3/vmxnet3_rxtx.c   | 59 ++++++++++++++++++++++++++++
 4 files changed, 63 insertions(+)

diff --git a/drivers/net/vmxnet3/Makefile b/drivers/net/vmxnet3/Makefile
index 9118501405..f1141da674 100644
--- a/drivers/net/vmxnet3/Makefile
+++ b/drivers/net/vmxnet3/Makefile
@@ -8,6 +8,7 @@ include $(RTE_SDK)/mk/rte.vars.mk
 #
 LIB = librte_pmd_vmxnet3_uio.a
 
+CFLAGS += -DALLOW_EXPERIMENTAL_API
 CFLAGS += -O3
 CFLAGS += $(WERROR_FLAGS)
 
diff --git a/drivers/net/vmxnet3/vmxnet3_ethdev.c b/drivers/net/vmxnet3/vmxnet3_ethdev.c
index 19f0325a5e..b5fb39e864 100644
--- a/drivers/net/vmxnet3/vmxnet3_ethdev.c
+++ b/drivers/net/vmxnet3/vmxnet3_ethdev.c
@@ -570,6 +570,8 @@ vmxnet3_setup_driver_shared(struct rte_eth_dev *dev)
 	uint32_t i;
 	int ret;
 
+	hw->mtu = mtu;
+
 	shared->magic = VMXNET3_REV1_MAGIC;
 	devRead->misc.driverInfo.version = VMXNET3_DRIVER_VERSION_NUM;
 
diff --git a/drivers/net/vmxnet3/vmxnet3_ethdev.h b/drivers/net/vmxnet3/vmxnet3_ethdev.h
index b2a8cf35b0..d3f2b35292 100644
--- a/drivers/net/vmxnet3/vmxnet3_ethdev.h
+++ b/drivers/net/vmxnet3/vmxnet3_ethdev.h
@@ -87,6 +87,7 @@ struct vmxnet3_hw {
 
 	uint64_t              queueDescPA;
 	uint16_t              queue_desc_len;
+	uint16_t              mtu;
 
 	VMXNET3_RSSConf       *rss_conf;
 	uint64_t              rss_confPA;
diff --git a/drivers/net/vmxnet3/vmxnet3_rxtx.c b/drivers/net/vmxnet3/vmxnet3_rxtx.c
index 5693c51428..02840fe033 100644
--- a/drivers/net/vmxnet3/vmxnet3_rxtx.c
+++ b/drivers/net/vmxnet3/vmxnet3_rxtx.c
@@ -646,6 +646,59 @@ vmxnet3_post_rx_bufs(vmxnet3_rx_queue_t *rxq, uint8_t ring_id)
 		return i;
 }
 
+/* MSS not provided by vmxnet3, guess one with available information */
+static uint16_t
+vmxnet3_guess_mss(struct vmxnet3_hw *hw, const Vmxnet3_RxCompDesc *rcd,
+		struct rte_mbuf *rxm)
+{
+	uint32_t hlen, slen;
+	struct ipv4_hdr *ipv4_hdr;
+	struct ipv6_hdr *ipv6_hdr;
+	struct tcp_hdr *tcp_hdr;
+	char *ptr;
+
+	RTE_ASSERT(rcd->tcp);
+
+	ptr = rte_pktmbuf_mtod(rxm, char *);
+	slen = rte_pktmbuf_data_len(rxm);
+	hlen = sizeof(struct ether_hdr);
+
+	if (rcd->v4) {
+		if (unlikely(slen < hlen + sizeof(struct ipv4_hdr)))
+			return hw->mtu - sizeof(struct ipv4_hdr)
+					- sizeof(struct tcp_hdr);
+
+		ipv4_hdr = (struct ipv4_hdr *)(ptr + hlen);
+		hlen += (ipv4_hdr->version_ihl & IPV4_HDR_IHL_MASK) *
+				IPV4_IHL_MULTIPLIER;
+	} else if (rcd->v6) {
+		if (unlikely(slen < hlen + sizeof(struct ipv6_hdr)))
+			return hw->mtu - sizeof(struct ipv6_hdr) -
+					sizeof(struct tcp_hdr);
+
+		ipv6_hdr = (struct ipv6_hdr *)(ptr + hlen);
+		hlen += sizeof(struct ipv6_hdr);
+		if (unlikely(ipv6_hdr->proto != IPPROTO_TCP)) {
+			int frag;
+
+			rte_net_skip_ip6_ext(ipv6_hdr->proto, rxm,
+					&hlen, &frag);
+		}
+	}
+
+	if (unlikely(slen < hlen + sizeof(struct tcp_hdr)))
+		return hw->mtu - hlen - sizeof(struct tcp_hdr) +
+				sizeof(struct ether_hdr);
+
+	tcp_hdr = (struct tcp_hdr *)(ptr + hlen);
+	hlen += (tcp_hdr->data_off & 0xf0) >> 2;
+
+	if (rxm->udata64 > 1)
+		return (rte_pktmbuf_pkt_len(rxm) - hlen +
+				rxm->udata64 - 1) / rxm->udata64;
+	else
+		return hw->mtu - hlen + sizeof(struct ether_hdr);
+}
 
 /* Receive side checksum and other offloads */
 static inline void
@@ -667,6 +720,7 @@ vmxnet3_rx_offload(struct vmxnet3_hw *hw, const Vmxnet3_RxCompDesc *rcd,
 					(const Vmxnet3_RxCompDescExt *)rcd;
 
 			rxm->tso_segsz = rcde->mss;
+			rxm->udata64 = rcde->segCnt;
 			ol_flags |= PKT_RX_LRO;
 		}
 	} else { /* Offloads set in eop */
@@ -730,6 +784,11 @@ vmxnet3_rx_offload(struct vmxnet3_hw *hw, const Vmxnet3_RxCompDesc *rcd,
 			} else {
 				packet_type |= RTE_PTYPE_UNKNOWN;
 			}
+
+			/* Old variants of vmxnet3 do not provide MSS */
+			if ((ol_flags & PKT_RX_LRO) && rxm->tso_segsz == 0)
+				rxm->tso_segsz = vmxnet3_guess_mss(hw,
+						rcd, rxm);
 		}
 	}