[PATCH] gro : fix pkt length when extra bytes are padded to ethernet frame

[Kumara Parameshwaran <kumaraparamesh92@gmail.com>]

From: Kumara Parameshwaran <kumaraparamesh92@gmail.com>

When GRO packets are merged the packet length is used while
merging the adjacent packets. If the padded bytes are accounted
we would end up acking unsent TCP segments.

Signed-off-by: Kumara Parameshwaran <kumaraparamesh92@gmail.com>
v1:
	If there is padding to the ethernet frame cases where timestamp is disabled
	the packet length should be validated with the total ip length as packet length 
	is used in the GRO merging logic

---
 lib/gro/gro_tcp4.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/lib/gro/gro_tcp4.c b/lib/gro/gro_tcp4.c
index 7498c66141..ac6439bb4e 100644
--- a/lib/gro/gro_tcp4.c
+++ b/lib/gro/gro_tcp4.c
@@ -198,7 +198,7 @@ gro_tcp4_reassemble(struct rte_mbuf *pkt,
 	struct rte_tcp_hdr *tcp_hdr;
 	uint32_t sent_seq;
 	int32_t tcp_dl;
-	uint16_t ip_id, hdr_len, frag_off;
+	uint16_t ip_id, hdr_len, frag_off, ip_len;
 	uint8_t is_atomic;
 
 	struct tcp4_flow_key key;
@@ -219,6 +219,12 @@ gro_tcp4_reassemble(struct rte_mbuf *pkt,
 	tcp_hdr = (struct rte_tcp_hdr *)((char *)ipv4_hdr + pkt->l3_len);
 	hdr_len = pkt->l2_len + pkt->l3_len + pkt->l4_len;
 
+	ip_len = rte_be_to_cpu_16(ipv4_hdr->total_length);
+	/* To handle padding cases in cases like where timestamps are disabled */
+	if (unlikely(pkt->pkt_len > (uint32_t)(ip_len + pkt->l2_len))) {
+		pkt->pkt_len = ip_len + pkt->l2_len;
+	}
+
 	/*
 	 * Don't process the packet which has FIN, SYN, RST, PSH, URG, ECE
 	 * or CWR set.
-- 
2.25.1