[PATCH v3 4/5] gso: add GRE GSO support

[Jiayu Hu <jiayu.hu@intel.com>]

From: Mark Kavanagh <mark.b.kavanagh@intel.com>

This patch adds GSO support for GRE-tunneled packets. Supported GRE
packets must contain an outer IPv4 header, and inner TCP/IPv4 headers.
They may also contain a single VLAN tag. GRE GSO assumes that all input
packets have correct checksums and doesn't update checksums for output
packets. Additionally, it doesn't process IP fragmented packets.

As with VxLAN GSO, GRE GSO uses a two-segment MBUF to organize each
output packet, which requires multi-segment mbuf support in the TX
functions of the NIC driver. Also, if a packet is GSOed, GRE GSO reduces
its MBUF refcnt by 1. As a result, when all of its GSOed segments are
freed, the packet is freed automatically.

Signed-off-by: Mark Kavanagh <mark.b.kavanagh@intel.com>
Signed-off-by: Jiayu Hu <jiayu.hu@intel.com>
---
 lib/librte_gso/gso_common.c | 22 ++++++++++++++++++++++
 lib/librte_gso/gso_common.h | 19 +++++++++++++++++++
 lib/librte_gso/rte_gso.c    |  3 ++-
 3 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/lib/librte_gso/gso_common.c b/lib/librte_gso/gso_common.c
index c6779d0..bd56924 100644
--- a/lib/librte_gso/gso_common.c
+++ b/lib/librte_gso/gso_common.c
@@ -37,6 +37,7 @@
 #include <rte_memcpy.h>
 #include <rte_mempool.h>
 #include <rte_ether.h>
+#include <rte_gre.h>
 #include <rte_ip.h>
 #include <rte_tcp.h>
 #include <rte_udp.h>
@@ -237,12 +238,33 @@ update_ipv4_vxlan_tcp4_header(struct rte_mbuf *pkt, uint8_t ipid_delta,
 	update_inner_tcp4_header(pkt, ipid_delta, segs, nb_segs);
 }
 
+static inline void
+update_ipv4_gre_tcp4_header(struct rte_mbuf *pkt, uint8_t ipid_delta,
+		struct rte_mbuf **segs, uint16_t nb_segs)
+{
+	struct ipv4_hdr *ipv4_hdr;
+	uint16_t i, id;
+
+	ipv4_hdr = (struct ipv4_hdr *)(rte_pktmbuf_mtod(pkt, char *) +
+			pkt->outer_l2_len);
+	id = rte_be_to_cpu_16(ipv4_hdr->packet_id);
+	for (i = 0; i < nb_segs; i++) {
+		update_outer_ipv4_header(segs[i], id);
+		id += ipid_delta;
+	}
+
+	/* Update inner TCP/IPv4 headers */
+	update_inner_tcp4_header(pkt, ipid_delta, segs, nb_segs);
+}
+
 void
 gso_update_pkt_headers(struct rte_mbuf *pkt, uint8_t ipid_delta,
 		struct rte_mbuf **segs, uint16_t nb_segs)
 {
 	if (is_ipv4_vxlan_ipv4_tcp(pkt->packet_type))
 		update_ipv4_vxlan_tcp4_header(pkt, ipid_delta, segs, nb_segs);
+	else if (is_ipv4_gre_ipv4_tcp(pkt->packet_type))
+		update_ipv4_gre_tcp4_header(pkt, ipid_delta, segs, nb_segs);
 	else if (is_ipv4_tcp(pkt->packet_type))
 		update_inner_tcp4_header(pkt, ipid_delta, segs, nb_segs);
 }
diff --git a/lib/librte_gso/gso_common.h b/lib/librte_gso/gso_common.h
index 2377a1d..f6d3238 100644
--- a/lib/librte_gso/gso_common.h
+++ b/lib/librte_gso/gso_common.h
@@ -89,6 +89,25 @@ static inline uint8_t is_ipv4_vxlan_ipv4_tcp(uint32_t ptype)
 	}
 }
 
+#define ETHER_GRE_TCP (RTE_PTYPE_L2_ETHER | RTE_PTYPE_TUNNEL_GRE | \
+		RTE_PTYPE_INNER_L4_TCP)
+#define ETHER_VLAN_GRE_TCP (RTE_PTYPE_L2_ETHER_VLAN | RTE_PTYPE_TUNNEL_GRE | \
+		RTE_PTYPE_INNER_L4_TCP)
+static inline uint8_t is_ipv4_gre_ipv4_tcp(uint32_t ptype)
+{
+	uint32_t type;
+
+	type = ptype & (~(RTE_PTYPE_L3_MASK | RTE_PTYPE_INNER_L3_MASK));
+	switch (type) {
+	case ETHER_GRE_TCP:
+	case ETHER_VLAN_GRE_TCP:
+		return (RTE_ETH_IS_IPV4_HDR(ptype) > 0) ?
+			IS_INNER_IPV4_HDR(ptype & RTE_PTYPE_INNER_L3_MASK) : 0;
+	default:
+		return 0;
+	}
+}
+
 /**
  * Internal function which updates relevant packet headers, following
  * segmentation. This is required to update, for example, the IPv4
diff --git a/lib/librte_gso/rte_gso.c b/lib/librte_gso/rte_gso.c
index 226c75a..e0925ae 100644
--- a/lib/librte_gso/rte_gso.c
+++ b/lib/librte_gso/rte_gso.c
@@ -67,7 +67,8 @@ rte_gso_segment(struct rte_mbuf *pkt,
 	gso_size = gso_ctx.gso_size;
 	ipid_delta = gso_ctx.ipid_flag == RTE_GSO_IPID_INCREASE;
 
-	if (is_ipv4_vxlan_ipv4_tcp(pkt->packet_type)) {
+	if (is_ipv4_vxlan_ipv4_tcp(pkt->packet_type) ||
+			is_ipv4_gre_ipv4_tcp(pkt->packet_type)) {
 		ret = gso_tunnel_tcp4_segment(pkt, gso_size, ipid_delta,
 				direct_pool, indirect_pool,
 				pkts_out, nb_pkts_out);
-- 
2.7.4