[PATCH net-next v7 0/3] net: qualcomm: rmnet: Enable Mapv5

This series introduces the MAPv5 packet format.

   Patch 0 documents the MAPv4/v5.
   Patch 1 introduces the MAPv5 and the Inline checksum offload for RX/Ingress.
   Patch 2 introduces the MAPv5 and the Inline checksum offload for TX/Egress.

   A new checksum header format is used as part of MAPv5.For RX checksum offload,
   the checksum is verified by the HW and the validity is marked in the checksum
   header of MAPv5. For TX, the required metadata is filled up so hardware can
   compute the checksum.

   v1->v2:
   - Fixed the compilation errors, warnings reported by kernel test robot.
   - Checksum header definition is expanded to support big, little endian
           formats as mentioned by Jakub.

   v2->v3:
   - Fixed compilation errors reported by kernel bot for big endian flavor.

   v3->v4:
   - Made changes to use masks instead of C bit-fields as suggested by Jakub/Alex.

   v4->v5:
   - Corrected checkpatch errors and warnings reported by patchwork.

   v5->v6:
   - Corrected the bug identified by Alex and incorporated all his comments.

   v6->v7:
   - Removed duplicate inclusion of linux/bitfield.h in rmnet_map_data.c

Sharath Chandra Vurukala (3):
  docs: networking: Add documentation for MAPv5
  net: ethernet: rmnet: Support for ingress MAPv5 checksum offload
  net: ethernet: rmnet: Add support for MAPv5 egress packets

 .../device_drivers/cellular/qualcomm/rmnet.rst     | 126 +++++++++++++++--
 drivers/net/ethernet/qualcomm/rmnet/rmnet_config.h |   4 +-
 .../net/ethernet/qualcomm/rmnet/rmnet_handlers.c   |  34 +++--
 drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h    |  11 +-
 .../net/ethernet/qualcomm/rmnet/rmnet_map_data.c   | 151 +++++++++++++++++++--
 drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c    |   3 +-
 include/linux/if_rmnet.h                           |  26 +++-
 include/uapi/linux/if_link.h                       |   2 +
 8 files changed, 320 insertions(+), 37 deletions(-)

-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

Adding support for processing of MAPv5 downlink packets.
It involves parsing the Mapv5 packet and checking the csum header
to know whether the hardware has validated the checksum and is
valid or not.

Based on the checksum valid bit the corresponding stats are
incremented and skb->ip_summed is marked either CHECKSUM_UNNECESSARY
or left as CHEKSUM_NONE to let network stack revalidate the checksum
and update the respective snmp stats.

Current MAPV1 header has been modified, the reserved field in the
Mapv1 header is now used for next header indication.

Signed-off-by: Sharath Chandra Vurukala <redacted>
---
 .../net/ethernet/qualcomm/rmnet/rmnet_handlers.c   | 17 ++++---
 drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h    |  3 +-
 .../net/ethernet/qualcomm/rmnet/rmnet_map_data.c   | 59 +++++++++++++++++++++-
 include/linux/if_rmnet.h                           | 26 +++++++++-
 include/uapi/linux/if_link.h                       |  1 +
 5 files changed, 96 insertions(+), 10 deletions(-)

diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c
index 0be5ac7..706a225 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-2.0-only
-/* Copyright (c) 2013-2018, The Linux Foundation. All rights reserved.
+/* Copyright (c) 2013-2018, 2021, The Linux Foundation. All rights reserved.
  *
  * RMNET Data ingress/egress handler
  */

@@ -82,11 +82,16 @@ __rmnet_map_ingress_handler(struct sk_buff *skb,
 
 	skb->dev = ep->egress_dev;
 
-	/* Subtract MAP header */
-	skb_pull(skb, sizeof(struct rmnet_map_header));
-	rmnet_set_skb_proto(skb);
-
-	if (port->data_format & RMNET_FLAGS_INGRESS_MAP_CKSUMV4) {
+	if ((port->data_format & RMNET_FLAGS_INGRESS_MAP_CKSUMV5) &&
+	    (map_header->flags & MAP_NEXT_HEADER_FLAG)) {
+		if (rmnet_map_process_next_hdr_packet(skb, len))
+			goto free_skb;
+		skb_pull(skb, sizeof(*map_header));
+		rmnet_set_skb_proto(skb);
+	} else if (port->data_format & RMNET_FLAGS_INGRESS_MAP_CKSUMV4) {
+		/* Subtract MAP header */
+		skb_pull(skb, sizeof(*map_header));
+		rmnet_set_skb_proto(skb);
 		if (!rmnet_map_checksum_downlink_packet(skb, len + pad))
 			skb->ip_summed = CHECKSUM_UNNECESSARY;
 	}

diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h
index 2aea153..1a399bf 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h

@@ -1,5 +1,5 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
-/* Copyright (c) 2013-2018, The Linux Foundation. All rights reserved.
+/* Copyright (c) 2013-2018, 2021, The Linux Foundation. All rights reserved.
  */
 
 #ifndef _RMNET_MAP_H_

@@ -48,5 +48,6 @@ void rmnet_map_command(struct sk_buff *skb, struct rmnet_port *port);
 int rmnet_map_checksum_downlink_packet(struct sk_buff *skb, u16 len);
 void rmnet_map_checksum_uplink_packet(struct sk_buff *skb,
 				      struct net_device *orig_dev);
+int rmnet_map_process_next_hdr_packet(struct sk_buff *skb, u16 len);
 
 #endif /* _RMNET_MAP_H_ */

diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
index 0ac2ff8..2280703 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-2.0-only
-/* Copyright (c) 2013-2018, The Linux Foundation. All rights reserved.
+/* Copyright (c) 2013-2018, 2021, The Linux Foundation. All rights reserved.
  *
  * RMNET Data MAP protocol
  */

@@ -8,6 +8,7 @@
 #include <linux/ip.h>
 #include <linux/ipv6.h>
 #include <net/ip6_checksum.h>
+#include <linux/bitfield.h>
 #include "rmnet_config.h"
 #include "rmnet_map.h"
 #include "rmnet_private.h"

@@ -300,8 +301,11 @@ struct rmnet_map_header *rmnet_map_add_map_header(struct sk_buff *skb,
 struct sk_buff *rmnet_map_deaggregate(struct sk_buff *skb,
 				      struct rmnet_port *port)
 {
+	struct rmnet_map_v5_csum_header *next_hdr = NULL;
+	void *data = skb->data;
 	struct rmnet_map_header *maph;
 	struct sk_buff *skbn;
+	u8 nexthdr_type;
 	u32 packet_len;
 
 	if (skb->len == 0)

@@ -310,8 +314,18 @@ struct sk_buff *rmnet_map_deaggregate(struct sk_buff *skb,
 	maph = (struct rmnet_map_header *)skb->data;
 	packet_len = ntohs(maph->pkt_len) + sizeof(*maph);
 
-	if (port->data_format & RMNET_FLAGS_INGRESS_MAP_CKSUMV4)
+	if (port->data_format & RMNET_FLAGS_INGRESS_MAP_CKSUMV4) {
 		packet_len += sizeof(struct rmnet_map_dl_csum_trailer);
+	} else if (port->data_format & RMNET_FLAGS_INGRESS_MAP_CKSUMV5) {
+		if (!(maph->flags & MAP_CMD_FLAG)) {
+			packet_len += sizeof(*next_hdr);
+			if (maph->flags & MAP_NEXT_HEADER_FLAG)
+				next_hdr = (data + sizeof(*maph));
+			else
+				/* Mapv5 data pkt without csum hdr is invalid */
+				return NULL;
+		}
+	}
 
 	if (((int)skb->len - (int)packet_len) < 0)
 		return NULL;

@@ -320,6 +334,13 @@ struct sk_buff *rmnet_map_deaggregate(struct sk_buff *skb,
 	if (!maph->pkt_len)
 		return NULL;
 
+	if (next_hdr) {
+		nexthdr_type = u8_get_bits(next_hdr->header_info,
+					   MAPV5_HDRINFO_HDR_TYPE_FMASK);
+		if (nexthdr_type != RMNET_MAP_HEADER_TYPE_CSUM_OFFLOAD)
+			return NULL;
+	}
+
 	skbn = alloc_skb(packet_len + RMNET_MAP_DEAGGR_SPACING, GFP_ATOMIC);
 	if (!skbn)
 		return NULL;

@@ -414,3 +435,37 @@ void rmnet_map_checksum_uplink_packet(struct sk_buff *skb,
 
 	priv->stats.csum_sw++;
 }
+
+/* Process a MAPv5 packet header */
+int rmnet_map_process_next_hdr_packet(struct sk_buff *skb,
+				      u16 len)
+{
+	struct rmnet_priv *priv = netdev_priv(skb->dev);
+	struct rmnet_map_v5_csum_header *next_hdr;
+	u8 nexthdr_type;
+	int rc = 0;
+
+	next_hdr = (struct rmnet_map_v5_csum_header *)(skb->data +
+			sizeof(struct rmnet_map_header));
+
+	nexthdr_type = u8_get_bits(next_hdr->header_info,
+				   MAPV5_HDRINFO_HDR_TYPE_FMASK);
+
+	if (nexthdr_type == RMNET_MAP_HEADER_TYPE_CSUM_OFFLOAD) {
+		if (unlikely(!(skb->dev->features & NETIF_F_RXCSUM))) {
+			priv->stats.csum_sw++;
+		} else if (next_hdr->csum_info & MAPV5_CSUMINFO_VALID_FLAG) {
+			priv->stats.csum_ok++;
+			skb->ip_summed = CHECKSUM_UNNECESSARY;
+		} else {
+			priv->stats.csum_valid_unset++;
+		}
+
+		/* Pull csum v5 header */
+		skb_pull(skb, sizeof(*next_hdr));
+	} else {
+		return -EINVAL;
+	}
+
+	return rc;
+}

diff --git a/include/linux/if_rmnet.h b/include/linux/if_rmnet.h
index 4efb537..8502ccc 100644
--- a/include/linux/if_rmnet.h
+++ b/include/linux/if_rmnet.h

@@ -1,5 +1,5 @@
 /* SPDX-License-Identifier: GPL-2.0-only
- * Copyright (c) 2013-2019, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2013-2019, 2021 The Linux Foundation. All rights reserved.
  */
 
 #ifndef _LINUX_IF_RMNET_H_

@@ -14,8 +14,10 @@ struct rmnet_map_header {
 /* rmnet_map_header flags field:
  *  PAD_LEN:	number of pad bytes following packet data
  *  CMD:	1 = packet contains a MAP command; 0 = packet contains data
+ *  NEXT_HEADER	1 = packet contains V5 CSUM header 0 = no V5 CSUM header
  */
 #define MAP_PAD_LEN_MASK		GENMASK(5, 0)
+#define MAP_NEXT_HEADER_FLAG		BIT(6)
 #define MAP_CMD_FLAG			BIT(7)
 
 struct rmnet_map_dl_csum_trailer {

@@ -45,4 +47,26 @@ struct rmnet_map_ul_csum_header {
 #define MAP_CSUM_UL_UDP_FLAG		BIT(14)
 #define MAP_CSUM_UL_ENABLED_FLAG	BIT(15)
 
+/* MAP CSUM headers */
+struct rmnet_map_v5_csum_header {
+	u8 header_info;
+	u8 csum_info;
+	__be16 reserved;
+} __aligned(1);
+
+/* v5 header_info field
+ * NEXT_HEADER:  Represents whether there is any other header
+ * HEADER TYPE: represents the type of this header
+ *
+ * csum_info field
+ * CSUM_VALID_OR_REQ:
+ * 1 = for UL, checksum computation is requested.
+ * 1 = for DL, validated the checksum and has found it valid
+ */
+
+#define MAPV5_HDRINFO_NXT_HDR_FLAG	BIT(0)
+#define MAPV5_HDRINFO_HDR_TYPE_FMASK	GENMASK(7, 1)
+#define MAPV5_CSUMINFO_VALID_FLAG	BIT(7)
+
+#define RMNET_MAP_HEADER_TYPE_CSUM_OFFLOAD 2
 #endif /* !(_LINUX_IF_RMNET_H_) */

diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index 91c8dda..21529b3 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h

@@ -1235,6 +1235,7 @@ enum {
 #define RMNET_FLAGS_INGRESS_MAP_COMMANDS          (1U << 1)
 #define RMNET_FLAGS_INGRESS_MAP_CKSUMV4           (1U << 2)
 #define RMNET_FLAGS_EGRESS_MAP_CKSUMV4            (1U << 3)
+#define RMNET_FLAGS_INGRESS_MAP_CKSUMV5           (1U << 4)
 
 enum {
 	IFLA_RMNET_UNSPEC,

-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

Adding support for MAPv5 egress packets.

This involves adding the MAPv5 header and setting the csum_valid_required
in the checksum header to request HW compute the checksum.

Corresponding stats are incremented based on whether the checksum is
computed in software or HW.

New stat has been added which represents the count of packets whose
checksum is calculated by the HW.

Signed-off-by: Sharath Chandra Vurukala <redacted>
---
 drivers/net/ethernet/qualcomm/rmnet/rmnet_config.h |  4 +-
 .../net/ethernet/qualcomm/rmnet/rmnet_handlers.c   | 17 ++--
 drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h    |  8 +-
 .../net/ethernet/qualcomm/rmnet/rmnet_map_data.c   | 92 ++++++++++++++++++++--
 drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c    |  3 +-
 include/uapi/linux/if_link.h                       |  1 +
 6 files changed, 110 insertions(+), 15 deletions(-)

diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.h b/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.h
index 8d8d469..8e64ca9 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.h
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.h

@@ -1,5 +1,6 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
-/* Copyright (c) 2013-2014, 2016-2018 The Linux Foundation. All rights reserved.
+/* Copyright (c) 2013-2014, 2016-2018, 2021 The Linux Foundation.
+ * All rights reserved.
  *
  * RMNET Data configuration engine
  */

@@ -56,6 +57,7 @@ struct rmnet_priv_stats {
 	u64 csum_fragmented_pkt;
 	u64 csum_skipped;
 	u64 csum_sw;
+	u64 csum_hw;
 };
 
 struct rmnet_priv {

diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c
index 706a225..03b3321 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c

@@ -133,7 +133,7 @@ static int rmnet_map_egress_handler(struct sk_buff *skb,
 				    struct rmnet_port *port, u8 mux_id,
 				    struct net_device *orig_dev)
 {
-	int required_headroom, additional_header_len;
+	int required_headroom, additional_header_len, csum_type = 0;
 	struct rmnet_map_header *map_header;
 
 	additional_header_len = 0;

@@ -141,18 +141,25 @@ static int rmnet_map_egress_handler(struct sk_buff *skb,
 
 	if (port->data_format & RMNET_FLAGS_EGRESS_MAP_CKSUMV4) {
 		additional_header_len = sizeof(struct rmnet_map_ul_csum_header);
-		required_headroom += additional_header_len;
+		csum_type = RMNET_FLAGS_EGRESS_MAP_CKSUMV4;
+	} else if (port->data_format & RMNET_FLAGS_EGRESS_MAP_CKSUMV5) {
+		additional_header_len = sizeof(struct rmnet_map_v5_csum_header);
+		csum_type = RMNET_FLAGS_EGRESS_MAP_CKSUMV5;
 	}
 
+	required_headroom += additional_header_len;
+
 	if (skb_headroom(skb) < required_headroom) {
 		if (pskb_expand_head(skb, required_headroom, 0, GFP_ATOMIC))
 			return -ENOMEM;
 	}
 
-	if (port->data_format & RMNET_FLAGS_EGRESS_MAP_CKSUMV4)
-		rmnet_map_checksum_uplink_packet(skb, orig_dev);
+	if (csum_type)
+		rmnet_map_checksum_uplink_packet(skb, port, orig_dev,
+						 csum_type);
 
-	map_header = rmnet_map_add_map_header(skb, additional_header_len, 0);
+	map_header = rmnet_map_add_map_header(skb, additional_header_len,
+					      port, 0);
 	if (!map_header)
 		return -ENOMEM;
 

diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h
index 1a399bf..e5a0b38 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h

@@ -43,11 +43,15 @@ enum rmnet_map_commands {
 struct sk_buff *rmnet_map_deaggregate(struct sk_buff *skb,
 				      struct rmnet_port *port);
 struct rmnet_map_header *rmnet_map_add_map_header(struct sk_buff *skb,
-						  int hdrlen, int pad);
+						  int hdrlen,
+						  struct rmnet_port *port,
+						  int pad);
 void rmnet_map_command(struct sk_buff *skb, struct rmnet_port *port);
 int rmnet_map_checksum_downlink_packet(struct sk_buff *skb, u16 len);
 void rmnet_map_checksum_uplink_packet(struct sk_buff *skb,
-				      struct net_device *orig_dev);
+				      struct rmnet_port *port,
+				      struct net_device *orig_dev,
+				      int csum_type);
 int rmnet_map_process_next_hdr_packet(struct sk_buff *skb, u16 len);
 
 #endif /* _RMNET_MAP_H_ */

diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
index 2280703..a375a46 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c

@@ -251,12 +251,69 @@ rmnet_map_ipv6_ul_csum_header(void *ip6hdr,
 }
 #endif
 
+static void rmnet_map_v5_checksum_uplink_packet(struct sk_buff *skb,
+						struct rmnet_port *port,
+						struct net_device *orig_dev)
+{
+	struct rmnet_priv *priv = netdev_priv(orig_dev);
+	struct rmnet_map_v5_csum_header *ul_header;
+
+	if (!(port->data_format & RMNET_FLAGS_EGRESS_MAP_CKSUMV5))
+		return;
+
+	ul_header = skb_push(skb, sizeof(*ul_header));
+	memset(ul_header, 0, sizeof(*ul_header));
+	ul_header->header_info = u8_encode_bits(RMNET_MAP_HEADER_TYPE_CSUM_OFFLOAD,
+						MAPV5_HDRINFO_HDR_TYPE_FMASK);
+
+	if (skb->ip_summed == CHECKSUM_PARTIAL) {
+		void *iph = (char *)ul_header + sizeof(*ul_header);
+		__sum16 *check;
+		void *trans;
+		u8 proto;
+
+		if (skb->protocol == htons(ETH_P_IP)) {
+			u16 ip_len = ((struct iphdr *)iph)->ihl * 4;
+
+			proto = ((struct iphdr *)iph)->protocol;
+			trans = iph + ip_len;
+		} else if (skb->protocol == htons(ETH_P_IPV6)) {
+#if IS_ENABLED(CONFIG_IPV6)
+			u16 ip_len = sizeof(struct ipv6hdr);
+
+			proto = ((struct ipv6hdr *)iph)->nexthdr;
+			trans = iph + ip_len;
+#else
+			priv->stats.csum_err_invalid_ip_version++;
+			goto sw_csum;
+#endif /* CONFIG_IPV6 */
+		} else {
+			priv->stats.csum_err_invalid_ip_version++;
+			goto sw_csum;
+		}
+
+		check = rmnet_map_get_csum_field(proto, trans);
+		if (check) {
+			skb->ip_summed = CHECKSUM_NONE;
+			/* Ask for checksum offloading */
+			ul_header->csum_info |= MAPV5_CSUMINFO_VALID_FLAG;
+			priv->stats.csum_hw++;
+			return;
+		}
+	}
+
+sw_csum:
+	priv->stats.csum_sw++;
+}
+
 /* Adds MAP header to front of skb->data
  * Padding is calculated and set appropriately in MAP header. Mux ID is
  * initialized to 0.
  */
 struct rmnet_map_header *rmnet_map_add_map_header(struct sk_buff *skb,
-						  int hdrlen, int pad)
+						  int hdrlen,
+						  struct rmnet_port *port,
+						  int pad)
 {
 	struct rmnet_map_header *map_header;
 	u32 padding, map_datalen;

@@ -267,6 +324,10 @@ struct rmnet_map_header *rmnet_map_add_map_header(struct sk_buff *skb,
 			skb_push(skb, sizeof(struct rmnet_map_header));
 	memset(map_header, 0, sizeof(struct rmnet_map_header));
 
+	/* Set next_hdr bit for csum offload packets */
+	if (port->data_format & RMNET_FLAGS_EGRESS_MAP_CKSUMV5)
+		map_header->flags |= MAP_NEXT_HEADER_FLAG;
+
 	if (pad == RMNET_MAP_NO_PAD_BYTES) {
 		map_header->pkt_len = htons(map_datalen);
 		return map_header;

@@ -393,11 +454,8 @@ int rmnet_map_checksum_downlink_packet(struct sk_buff *skb, u16 len)
 	return 0;
 }
 
-/* Generates UL checksum meta info header for IPv4 and IPv6 over TCP and UDP
- * packets that are supported for UL checksum offload.
- */
-void rmnet_map_checksum_uplink_packet(struct sk_buff *skb,
-				      struct net_device *orig_dev)
+static void rmnet_map_v4_checksum_uplink_packet(struct sk_buff *skb,
+						struct net_device *orig_dev)
 {
 	struct rmnet_priv *priv = netdev_priv(orig_dev);
 	struct rmnet_map_ul_csum_header *ul_header;

@@ -416,10 +474,12 @@ void rmnet_map_checksum_uplink_packet(struct sk_buff *skb,
 
 		if (skb->protocol == htons(ETH_P_IP)) {
 			rmnet_map_ipv4_ul_csum_header(iphdr, ul_header, skb);
+			priv->stats.csum_hw++;
 			return;
 		} else if (skb->protocol == htons(ETH_P_IPV6)) {
 #if IS_ENABLED(CONFIG_IPV6)
 			rmnet_map_ipv6_ul_csum_header(iphdr, ul_header, skb);
+			priv->stats.csum_hw++;
 			return;
 #else
 			priv->stats.csum_err_invalid_ip_version++;

@@ -436,6 +496,26 @@ void rmnet_map_checksum_uplink_packet(struct sk_buff *skb,
 	priv->stats.csum_sw++;
 }
 
+/* Generates UL checksum meta info header for IPv4 and IPv6 over TCP and UDP
+ * packets that are supported for UL checksum offload.
+ */
+void rmnet_map_checksum_uplink_packet(struct sk_buff *skb,
+				      struct rmnet_port *port,
+				      struct net_device *orig_dev,
+				      int csum_type)
+{
+	switch (csum_type) {
+	case RMNET_FLAGS_EGRESS_MAP_CKSUMV4:
+		rmnet_map_v4_checksum_uplink_packet(skb, orig_dev);
+		break;
+	case RMNET_FLAGS_EGRESS_MAP_CKSUMV5:
+		rmnet_map_v5_checksum_uplink_packet(skb, port, orig_dev);
+		break;
+	default:
+		break;
+	}
+}
+
 /* Process a MAPv5 packet header */
 int rmnet_map_process_next_hdr_packet(struct sk_buff *skb,
 				      u16 len)

diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c
index 41fbd2c..bc6d6ac 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c

@@ -174,6 +174,7 @@ static const char rmnet_gstrings_stats[][ETH_GSTRING_LEN] = {
 	"Checksum skipped on ip fragment",
 	"Checksum skipped",
 	"Checksum computed in software",
+	"Checksum computed in hardware",
 };
 
 static void rmnet_get_strings(struct net_device *dev, u32 stringset, u8 *buf)

@@ -354,4 +355,4 @@ int rmnet_vnd_update_dev_mtu(struct rmnet_port *port,
 	}
 
 	return 0;
-}

\ No newline at end of file
+}

diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index 21529b3..1691f3a 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h

@@ -1236,6 +1236,7 @@ enum {
 #define RMNET_FLAGS_INGRESS_MAP_CKSUMV4           (1U << 2)
 #define RMNET_FLAGS_EGRESS_MAP_CKSUMV4            (1U << 3)
 #define RMNET_FLAGS_INGRESS_MAP_CKSUMV5           (1U << 4)
+#define RMNET_FLAGS_EGRESS_MAP_CKSUMV5            (1U << 5)
 
 enum {
 	IFLA_RMNET_UNSPEC,

-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

Adding documentation explaining the new MAPv4/v5 packet formats
and the corresponding checksum offload headers.

Signed-off-by: Sharath Chandra Vurukala <redacted>
---
 .../device_drivers/cellular/qualcomm/rmnet.rst     | 126 +++++++++++++++++++--
 1 file changed, 114 insertions(+), 12 deletions(-)

diff --git a/Documentation/networking/device_drivers/cellular/qualcomm/rmnet.rst b/Documentation/networking/device_drivers/cellular/qualcomm/rmnet.rst
index 70643b5..4118384 100644
--- a/Documentation/networking/device_drivers/cellular/qualcomm/rmnet.rst
+++ b/Documentation/networking/device_drivers/cellular/qualcomm/rmnet.rst

@@ -27,34 +27,136 @@ these MAP frames and send them to appropriate PDN's.
 2. Packet format
 ================
 
-a. MAP packet (data / control)
+a. MAP packet v1 (data / control)
 
-MAP header has the same endianness of the IP packet.
+MAP header fields are in big endian format.
 
 Packet format::
 
-  Bit             0             1           2-7      8 - 15           16 - 31
+  Bit             0             1           2-7      8-15           16-31
   Function   Command / Data   Reserved     Pad   Multiplexer ID    Payload length
-  Bit            32 - x
-  Function     Raw  Bytes
+
+  Bit            32-x
+  Function      Raw bytes
 
 Command (1)/ Data (0) bit value is to indicate if the packet is a MAP command
-or data packet. Control packet is used for transport level flow control. Data
+or data packet. Command packet is used for transport level flow control. Data
 packets are standard IP packets.
 
-Reserved bits are usually zeroed out and to be ignored by receiver.
+Reserved bits must be zero when sent and ignored when received.
 
-Padding is number of bytes to be added for 4 byte alignment if required by
-hardware.
+Padding is the number of bytes to be appended to the payload to
+ensure 4 byte alignment.
 
 Multiplexer ID is to indicate the PDN on which data has to be sent.
 
 Payload length includes the padding length but does not include MAP header
 length.
 
-b. MAP packet (command specific)::
+b. Map packet v4 (data / control)
+
+MAP header fields are in big endian format.
+
+Packet format::
+
+  Bit             0             1           2-7      8-15           16-31
+  Function   Command / Data   Reserved     Pad   Multiplexer ID    Payload length
+
+  Bit            32-(x-33)      (x-32)-x
+  Function      Raw bytes      Checksum offload header
+
+Command (1)/ Data (0) bit value is to indicate if the packet is a MAP command
+or data packet. Command packet is used for transport level flow control. Data
+packets are standard IP packets.
+
+Reserved bits must be zero when sent and ignored when received.
+
+Padding is the number of bytes to be appended to the payload to
+ensure 4 byte alignment.
+
+Multiplexer ID is to indicate the PDN on which data has to be sent.
+
+Payload length includes the padding length but does not include MAP header
+length.
+
+Checksum offload header, has the information about the checksum processing done
+by the hardware.Checksum offload header fields are in big endian format.
+
+Packet format::
+
+  Bit             0-14        15              16-31
+  Function      Reserved   Valid     Checksum start offset
+
+  Bit                31-47                    48-64
+  Function      Checksum length           Checksum value
+
+Reserved bits must be zero when sent and ignored when received.
+
+Valid bit indicates whether the partial checksum is calculated and is valid.
+Set to 1, if its is valid. Set to 0 otherwise.
+
+Padding is the number of bytes to be appended to the payload to
+ensure 4 byte alignment.
+
+Checksum start offset, Indicates the offset in bytes from the beginning of the
+IP header, from which modem computed checksum.
+
+Checksum length is the Length in bytes starting from CKSUM_START_OFFSET,
+over which checksum is computed.
+
+Checksum value, indicates the checksum computed.
+
+c. MAP packet v5 (data / control)
+
+MAP header fields are in big endian format.
+
+Packet format::
+
+  Bit             0             1         2-7      8-15           16-31
+  Function   Command / Data  Next header  Pad   Multiplexer ID   Payload length
+
+  Bit            32-x
+  Function      Raw bytes
+
+Command (1)/ Data (0) bit value is to indicate if the packet is a MAP command
+or data packet. Command packet is used for transport level flow control. Data
+packets are standard IP packets.
+
+Next header is used to indicate the presence of another header, currently is
+limited to checksum header.
+
+Padding is the number of bytes to be appended to the payload to
+ensure 4 byte alignment.
+
+Multiplexer ID is to indicate the PDN on which data has to be sent.
+
+Payload length includes the padding length but does not include MAP header
+length.
+
+d. Checksum offload header v5
+
+Checksum offload header fields are in big endian format.
+
+  Bit            0 - 6          7               8-15              16-31
+  Function     Header Type    Next Header     Checksum Valid    Reserved
+
+Header Type is to indicate the type of header, this usually is set to CHECKSUM
+
+Header types
+= ==========================================
+0 Reserved
+1 Reserved
+2 checksum header
+
+Checksum Valid is to indicate whether the header checksum is valid. Value of 1
+implies that checksum is calculated on this packet and is valid, value of 0
+indicates that the calculated packet checksum is invalid.
+
+Reserved bits must be zero when sent and ignored when received.
+
+e. MAP packet v1/v5 (command specific)::
 
-    Bit             0             1           2-7      8 - 15           16 - 31
+    Bit             0             1         2-7      8 - 15           16 - 31
     Function   Command         Reserved     Pad   Multiplexer ID    Payload length
     Bit          32 - 39        40 - 45    46 - 47       48 - 63
     Function   Command name    Reserved   Command Type   Reserved

@@ -74,7 +176,7 @@ Command types
 3 is for error during processing of commands
 = ==========================================
 
-c. Aggregation
+f. Aggregation
 
 Aggregation is multiple MAP packets (can be data or command) delivered to
 rmnet in a single linear skb. rmnet will process the individual

-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

On 2021-05-27 02:48, Sharath Chandra Vurukala wrote:

This series introduces the MAPv5 packet format.

   Patch 0 documents the MAPv4/v5.
   Patch 1 introduces the MAPv5 and the Inline checksum offload for
RX/Ingress.
   Patch 2 introduces the MAPv5 and the Inline checksum offload for
TX/Egress.

   A new checksum header format is used as part of MAPv5.For RX 
checksum
offload,
   the checksum is verified by the HW and the validity is marked in the
checksum
   header of MAPv5. For TX, the required metadata is filled up so 
hardware
can
   compute the checksum.

   v1->v2:
   - Fixed the compilation errors, warnings reported by kernel test 
robot.
   - Checksum header definition is expanded to support big, little 
endian
           formats as mentioned by Jakub.

   v2->v3:
   - Fixed compilation errors reported by kernel bot for big endian
flavor.

   v3->v4:
   - Made changes to use masks instead of C bit-fields as suggested by
Jakub/Alex.

   v4->v5:
   - Corrected checkpatch errors and warnings reported by patchwork.

   v5->v6:
   - Corrected the bug identified by Alex and incorporated all his
comments.

   v6->v7:
   - Removed duplicate inclusion of linux/bitfield.h in 
rmnet_map_data.c

Sharath Chandra Vurukala (3):
  docs: networking: Add documentation for MAPv5
  net: ethernet: rmnet: Support for ingress MAPv5 checksum offload
  net: ethernet: rmnet: Add support for MAPv5 egress packets

 .../device_drivers/cellular/qualcomm/rmnet.rst     | 126
+++++++++++++++--
 drivers/net/ethernet/qualcomm/rmnet/rmnet_config.h |   4 +-
 .../net/ethernet/qualcomm/rmnet/rmnet_handlers.c   |  34 +++--
 drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h    |  11 +-
 .../net/ethernet/qualcomm/rmnet/rmnet_map_data.c   | 151
+++++++++++++++++++--
 drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c    |   3 +-
 include/linux/if_rmnet.h                           |  26 +++-
 include/uapi/linux/if_link.h                       |   2 +
 8 files changed, 320 insertions(+), 37 deletions(-)

For the series-

Reviewed-by: Subash Abhinov Kasiviswanathan <redacted>

On Thu, 27 May 2021 14:18:41 +0530 Sharath Chandra Vurukala wrote:

Adding support for processing of MAPv5 downlink packets.
It involves parsing the Mapv5 packet and checking the csum header
to know whether the hardware has validated the checksum and is
valid or not.

Based on the checksum valid bit the corresponding stats are
incremented and skb->ip_summed is marked either CHECKSUM_UNNECESSARY
or left as CHEKSUM_NONE to let network stack revalidate the checksum
and update the respective snmp stats.

Current MAPV1 header has been modified, the reserved field in the
Mapv1 header is now used for next header indication.

Signed-off-by: Sharath Chandra Vurukala <redacted>

Please maintain reverse xmas tree ordering

brackets unnecessary

rc is not meaningfully used

+	next_hdr = (struct rmnet_map_v5_csum_header *)(skb->data +
+			sizeof(struct rmnet_map_header));
+
+	nexthdr_type = u8_get_bits(next_hdr->header_info,
+				   MAPV5_HDRINFO_HDR_TYPE_FMASK);
+
+	if (nexthdr_type == RMNET_MAP_HEADER_TYPE_CSUM_OFFLOAD) {
+		if (unlikely(!(skb->dev->features & NETIF_F_RXCSUM))) {
+			priv->stats.csum_sw++;
+		} else if (next_hdr->csum_info & MAPV5_CSUMINFO_VALID_FLAG) {
+			priv->stats.csum_ok++;
+			skb->ip_summed = CHECKSUM_UNNECESSARY;
+		} else {
+			priv->stats.csum_valid_unset++;
+		}
+
+		/* Pull csum v5 header */
+		skb_pull(skb, sizeof(*next_hdr));
+	} else {
+		return -EINVAL;

flip condition, return early

Colon missing?

__aligned() seems rather pointless here but ok.

+/* v5 header_info field
+ * NEXT_HEADER:  Represents whether there is any other header

double space

+ * HEADER TYPE: represents the type of this header

On previous line you used _ for a space, and started from capital
letter. Please be consistent.

+ *
+ * csum_info field
+ * CSUM_VALID_OR_REQ:
+ * 1 = for UL, checksum computation is requested.
+ * 1 = for DL, validated the checksum and has found it valid
+ */
+
+#define MAPV5_HDRINFO_NXT_HDR_FLAG	BIT(0)
+#define MAPV5_HDRINFO_HDR_TYPE_FMASK	GENMASK(7, 1)
+#define MAPV5_CSUMINFO_VALID_FLAG	BIT(7)
+
+#define RMNET_MAP_HEADER_TYPE_CSUM_OFFLOAD 2
 #endif /* !(_LINUX_IF_RMNET_H_) */

On Thu, 27 May 2021 14:18:42 +0530 Sharath Chandra Vurukala wrote:

Adding support for MAPv5 egress packets.

This involves adding the MAPv5 header and setting the csum_valid_required
in the checksum header to request HW compute the checksum.

Corresponding stats are incremented based on whether the checksum is
computed in software or HW.

New stat has been added which represents the count of packets whose
checksum is calculated by the HW.

Signed-off-by: Sharath Chandra Vurukala <redacted>

+static void rmnet_map_v5_checksum_uplink_packet(struct sk_buff *skb,
+						struct rmnet_port *port,
+						struct net_device *orig_dev)
+{
+	struct rmnet_priv *priv = netdev_priv(orig_dev);
+	struct rmnet_map_v5_csum_header *ul_header;
+
+	if (!(port->data_format & RMNET_FLAGS_EGRESS_MAP_CKSUMV5))
+		return;

how can we get here if this condition is not met? Looks like defensive
programming.

+	ul_header = skb_push(skb, sizeof(*ul_header));

Are you making sure you can modify head? I only see a check if there is
enough headroom but not if head is writable (skb_cow_head()).

+	memset(ul_header, 0, sizeof(*ul_header));
+	ul_header->header_info = u8_encode_bits(RMNET_MAP_HEADER_TYPE_CSUM_OFFLOAD,
+						MAPV5_HDRINFO_HDR_TYPE_FMASK);

Is prepending the header required even when packet doesn't need
checksuming?

+	if (skb->ip_summed == CHECKSUM_PARTIAL) {
+		void *iph = (char *)ul_header + sizeof(*ul_header);

ip_hdr(skb)

+		__sum16 *check;
+		void *trans;
+		u8 proto;
+
+		if (skb->protocol == htons(ETH_P_IP)) {
+			u16 ip_len = ((struct iphdr *)iph)->ihl * 4;
+
+			proto = ((struct iphdr *)iph)->protocol;
+			trans = iph + ip_len;
+		} else if (skb->protocol == htons(ETH_P_IPV6)) {
+#if IS_ENABLED(CONFIG_IPV6)
+			u16 ip_len = sizeof(struct ipv6hdr);
+
+			proto = ((struct ipv6hdr *)iph)->nexthdr;
+			trans = iph + ip_len;
+#else
+			priv->stats.csum_err_invalid_ip_version++;
+			goto sw_csum;
+#endif /* CONFIG_IPV6 */
+		} else {
+			priv->stats.csum_err_invalid_ip_version++;
+			goto sw_csum;
+		}
+
+		check = rmnet_map_get_csum_field(proto, trans);
+		if (check) {
+			skb->ip_summed = CHECKSUM_NONE;
+			/* Ask for checksum offloading */
+			ul_header->csum_info |= MAPV5_CSUMINFO_VALID_FLAG;
+			priv->stats.csum_hw++;
+			return;

Please try to keep the success path unindented.

+		}
+	}
+
+sw_csum:
+	priv->stats.csum_sw++;
+}

On 5/28/21 5:58 PM, Jakub Kicinski wrote:

On Thu, 27 May 2021 14:18:41 +0530 Sharath Chandra Vurukala wrote:

quoted

Adding support for processing of MAPv5 downlink packets.
It involves parsing the Mapv5 packet and checking the csum header
to know whether the hardware has validated the checksum and is
valid or not.

Nice review Jakub.  I will wait for version 8 and will review that.

					-Alex

quoted

Based on the checksum valid bit the corresponding stats are
incremented and skb->ip_summed is marked either CHECKSUM_UNNECESSARY
or left as CHEKSUM_NONE to let network stack revalidate the checksum
and update the respective snmp stats.

Current MAPV1 header has been modified, the reserved field in the
Mapv1 header is now used for next header indication.

Signed-off-by: Sharath Chandra Vurukala <redacted>

quoted

@@ -300,8 +301,11 @@ struct rmnet_map_header *rmnet_map_add_map_header(struct sk_buff *skb,
 struct sk_buff *rmnet_map_deaggregate(struct sk_buff *skb,
 				      struct rmnet_port *port)
 {
+	struct rmnet_map_v5_csum_header *next_hdr = NULL;
+	void *data = skb->data;
 	struct rmnet_map_header *maph;

Please maintain reverse xmas tree ordering

quoted

 	struct sk_buff *skbn;
+	u8 nexthdr_type;
 	u32 packet_len;
 
 	if (skb->len == 0)

@@ -310,8 +314,18 @@ struct sk_buff *rmnet_map_deaggregate(struct sk_buff *skb,
 	maph = (struct rmnet_map_header *)skb->data;
 	packet_len = ntohs(maph->pkt_len) + sizeof(*maph);
 
-	if (port->data_format & RMNET_FLAGS_INGRESS_MAP_CKSUMV4)
+	if (port->data_format & RMNET_FLAGS_INGRESS_MAP_CKSUMV4) {
 		packet_len += sizeof(struct rmnet_map_dl_csum_trailer);
+	} else if (port->data_format & RMNET_FLAGS_INGRESS_MAP_CKSUMV5) {
+		if (!(maph->flags & MAP_CMD_FLAG)) {
+			packet_len += sizeof(*next_hdr);
+			if (maph->flags & MAP_NEXT_HEADER_FLAG)
+				next_hdr = (data + sizeof(*maph));

brackets unnecessary

quoted

+			else
+				/* Mapv5 data pkt without csum hdr is invalid */
+				return NULL;
+		}
+	}
 
 	if (((int)skb->len - (int)packet_len) < 0)
 		return NULL;

@@ -320,6 +334,13 @@ struct sk_buff *rmnet_map_deaggregate(struct sk_buff *skb,
 	if (!maph->pkt_len)
 		return NULL;
 
+	if (next_hdr) {
+		nexthdr_type = u8_get_bits(next_hdr->header_info,
+					   MAPV5_HDRINFO_HDR_TYPE_FMASK);
+		if (nexthdr_type != RMNET_MAP_HEADER_TYPE_CSUM_OFFLOAD)
+			return NULL;
+	}
+
 	skbn = alloc_skb(packet_len + RMNET_MAP_DEAGGR_SPACING, GFP_ATOMIC);
 	if (!skbn)
 		return NULL;

@@ -414,3 +435,37 @@ void rmnet_map_checksum_uplink_packet(struct sk_buff *skb,
 
 	priv->stats.csum_sw++;
 }
+
+/* Process a MAPv5 packet header */
+int rmnet_map_process_next_hdr_packet(struct sk_buff *skb,
+				      u16 len)
+{
+	struct rmnet_priv *priv = netdev_priv(skb->dev);
+	struct rmnet_map_v5_csum_header *next_hdr;
+	u8 nexthdr_type;
+	int rc = 0;

rc is not meaningfully used

quoted

+	next_hdr = (struct rmnet_map_v5_csum_header *)(skb->data +
+			sizeof(struct rmnet_map_header));
+
+	nexthdr_type = u8_get_bits(next_hdr->header_info,
+				   MAPV5_HDRINFO_HDR_TYPE_FMASK);
+
+	if (nexthdr_type == RMNET_MAP_HEADER_TYPE_CSUM_OFFLOAD) {
+		if (unlikely(!(skb->dev->features & NETIF_F_RXCSUM))) {
+			priv->stats.csum_sw++;
+		} else if (next_hdr->csum_info & MAPV5_CSUMINFO_VALID_FLAG) {
+			priv->stats.csum_ok++;
+			skb->ip_summed = CHECKSUM_UNNECESSARY;
+		} else {
+			priv->stats.csum_valid_unset++;
+		}
+
+		/* Pull csum v5 header */
+		skb_pull(skb, sizeof(*next_hdr));
+	} else {
+		return -EINVAL;

flip condition, return early

quoted

+	}
+
+	return rc;
+}

diff --git a/include/linux/if_rmnet.h b/include/linux/if_rmnet.h
index 4efb537..8502ccc 100644
--- a/include/linux/if_rmnet.h
+++ b/include/linux/if_rmnet.h

@@ -1,5 +1,5 @@
 /* SPDX-License-Identifier: GPL-2.0-only
- * Copyright (c) 2013-2019, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2013-2019, 2021 The Linux Foundation. All rights reserved.
  */
 
 #ifndef _LINUX_IF_RMNET_H_

@@ -14,8 +14,10 @@ struct rmnet_map_header {
 /* rmnet_map_header flags field:
  *  PAD_LEN:	number of pad bytes following packet data
  *  CMD:	1 = packet contains a MAP command; 0 = packet contains data
+ *  NEXT_HEADER	1 = packet contains V5 CSUM header 0 = no V5 CSUM header

Colon missing?

quoted

  */
 #define MAP_PAD_LEN_MASK		GENMASK(5, 0)
+#define MAP_NEXT_HEADER_FLAG		BIT(6)
 #define MAP_CMD_FLAG			BIT(7)
 
 struct rmnet_map_dl_csum_trailer {

@@ -45,4 +47,26 @@ struct rmnet_map_ul_csum_header {
 #define MAP_CSUM_UL_UDP_FLAG		BIT(14)
 #define MAP_CSUM_UL_ENABLED_FLAG	BIT(15)
 
+/* MAP CSUM headers */
+struct rmnet_map_v5_csum_header {
+	u8 header_info;
+	u8 csum_info;
+	__be16 reserved;
+} __aligned(1);

__aligned() seems rather pointless here but ok.

quoted

+/* v5 header_info field
+ * NEXT_HEADER:  Represents whether there is any other header

double space

quoted

+ * HEADER TYPE: represents the type of this header

On previous line you used _ for a space, and started from capital
letter. Please be consistent.

quoted

+ *
+ * csum_info field
+ * CSUM_VALID_OR_REQ:
+ * 1 = for UL, checksum computation is requested.
+ * 1 = for DL, validated the checksum and has found it valid
+ */
+
+#define MAPV5_HDRINFO_NXT_HDR_FLAG	BIT(0)
+#define MAPV5_HDRINFO_HDR_TYPE_FMASK	GENMASK(7, 1)
+#define MAPV5_CSUMINFO_VALID_FLAG	BIT(7)
+
+#define RMNET_MAP_HEADER_TYPE_CSUM_OFFLOAD 2
 #endif /* !(_LINUX_IF_RMNET_H_) */

On 2021-05-29 04:28, Jakub Kicinski wrote:

On Thu, 27 May 2021 14:18:41 +0530 Sharath Chandra Vurukala wrote:

quoted

Adding support for processing of MAPv5 downlink packets.
It involves parsing the Mapv5 packet and checking the csum header
to know whether the hardware has validated the checksum and is
valid or not.

Based on the checksum valid bit the corresponding stats are
incremented and skb->ip_summed is marked either CHECKSUM_UNNECESSARY
or left as CHEKSUM_NONE to let network stack revalidate the checksum
and update the respective snmp stats.

Current MAPV1 header has been modified, the reserved field in the
Mapv1 header is now used for next header indication.

Signed-off-by: Sharath Chandra Vurukala <redacted>

quoted

@@ -300,8 +301,11 @@ struct rmnet_map_header 

*rmnet_map_add_map_header(struct sk_buff *skb,
 struct sk_buff *rmnet_map_deaggregate(struct sk_buff *skb,
 				      struct rmnet_port *port)
 {
+	struct rmnet_map_v5_csum_header *next_hdr = NULL;
+	void *data = skb->data;
 	struct rmnet_map_header *maph;

Please maintain reverse xmas tree ordering

Thanks Jakub for the review, I will address all the comments that you 
gave in the next subsequent patch.

quoted

 	struct sk_buff *skbn;
+	u8 nexthdr_type;
 	u32 packet_len;

 	if (skb->len == 0)

@@ -310,8 +314,18 @@ struct sk_buff *rmnet_map_deaggregate(struct 

sk_buff *skb,
 	maph = (struct rmnet_map_header *)skb->data;
 	packet_len = ntohs(maph->pkt_len) + sizeof(*maph);

-	if (port->data_format & RMNET_FLAGS_INGRESS_MAP_CKSUMV4)
+	if (port->data_format & RMNET_FLAGS_INGRESS_MAP_CKSUMV4) {
 		packet_len += sizeof(struct rmnet_map_dl_csum_trailer);
+	} else if (port->data_format & RMNET_FLAGS_INGRESS_MAP_CKSUMV5) {
+		if (!(maph->flags & MAP_CMD_FLAG)) {
+			packet_len += sizeof(*next_hdr);
+			if (maph->flags & MAP_NEXT_HEADER_FLAG)
+				next_hdr = (data + sizeof(*maph));

brackets unnecessary

Will take care in next patch.

quoted

+			else
+				/* Mapv5 data pkt without csum hdr is invalid */
+				return NULL;
+		}
+	}

 	if (((int)skb->len - (int)packet_len) < 0)
 		return NULL;

@@ -320,6 +334,13 @@ struct sk_buff *rmnet_map_deaggregate(struct 

sk_buff *skb,
 	if (!maph->pkt_len)
 		return NULL;

+	if (next_hdr) {
+		nexthdr_type = u8_get_bits(next_hdr->header_info,
+					   MAPV5_HDRINFO_HDR_TYPE_FMASK);
+		if (nexthdr_type != RMNET_MAP_HEADER_TYPE_CSUM_OFFLOAD)
+			return NULL;
+	}
+
 	skbn = alloc_skb(packet_len + RMNET_MAP_DEAGGR_SPACING, GFP_ATOMIC);
 	if (!skbn)
 		return NULL;

@@ -414,3 +435,37 @@ void rmnet_map_checksum_uplink_packet(struct 

sk_buff *skb,

 	priv->stats.csum_sw++;
 }
+
+/* Process a MAPv5 packet header */
+int rmnet_map_process_next_hdr_packet(struct sk_buff *skb,
+				      u16 len)
+{
+	struct rmnet_priv *priv = netdev_priv(skb->dev);
+	struct rmnet_map_v5_csum_header *next_hdr;
+	u8 nexthdr_type;
+	int rc = 0;

rc is not meaningfully used

quoted

+	next_hdr = (struct rmnet_map_v5_csum_header *)(skb->data +
+			sizeof(struct rmnet_map_header));
+
+	nexthdr_type = u8_get_bits(next_hdr->header_info,
+				   MAPV5_HDRINFO_HDR_TYPE_FMASK);
+
+	if (nexthdr_type == RMNET_MAP_HEADER_TYPE_CSUM_OFFLOAD) {
+		if (unlikely(!(skb->dev->features & NETIF_F_RXCSUM))) {
+			priv->stats.csum_sw++;
+		} else if (next_hdr->csum_info & MAPV5_CSUMINFO_VALID_FLAG) {
+			priv->stats.csum_ok++;
+			skb->ip_summed = CHECKSUM_UNNECESSARY;
+		} else {
+			priv->stats.csum_valid_unset++;
+		}
+
+		/* Pull csum v5 header */
+		skb_pull(skb, sizeof(*next_hdr));
+	} else {
+		return -EINVAL;

flip condition, return early

Sure will take care in next patch.

quoted

+	}
+
+	return rc;
+}

diff --git a/include/linux/if_rmnet.h b/include/linux/if_rmnet.h
index 4efb537..8502ccc 100644
--- a/include/linux/if_rmnet.h
+++ b/include/linux/if_rmnet.h

@@ -1,5 +1,5 @@
 /* SPDX-License-Identifier: GPL-2.0-only
- * Copyright (c) 2013-2019, The Linux Foundation. All rights 

reserved.
+ * Copyright (c) 2013-2019, 2021 The Linux Foundation. All rights 
reserved.
  */

 #ifndef _LINUX_IF_RMNET_H_

@@ -14,8 +14,10 @@ struct rmnet_map_header {
 /* rmnet_map_header flags field:
  *  PAD_LEN:	number of pad bytes following packet data
  *  CMD:	1 = packet contains a MAP command; 0 = packet contains data
+ *  NEXT_HEADER	1 = packet contains V5 CSUM header 0 = no V5 CSUM 

header

Colon missing?

quoted

  */
 #define MAP_PAD_LEN_MASK		GENMASK(5, 0)
+#define MAP_NEXT_HEADER_FLAG		BIT(6)
 #define MAP_CMD_FLAG			BIT(7)

 struct rmnet_map_dl_csum_trailer {

@@ -45,4 +47,26 @@ struct rmnet_map_ul_csum_header {
 #define MAP_CSUM_UL_UDP_FLAG		BIT(14)
 #define MAP_CSUM_UL_ENABLED_FLAG	BIT(15)

+/* MAP CSUM headers */
+struct rmnet_map_v5_csum_header {
+	u8 header_info;
+	u8 csum_info;
+	__be16 reserved;
+} __aligned(1);

__aligned() seems rather pointless here but ok.

quoted

+/* v5 header_info field
+ * NEXT_HEADER:  Represents whether there is any other header

double space

quoted

+ * HEADER TYPE: represents the type of this header

On previous line you used _ for a space, and started from capital
letter. Please be consistent.

Sure, will take care in next patch.

quoted

+ *
+ * csum_info field
+ * CSUM_VALID_OR_REQ:
+ * 1 = for UL, checksum computation is requested.
+ * 1 = for DL, validated the checksum and has found it valid
+ */
+
+#define MAPV5_HDRINFO_NXT_HDR_FLAG	BIT(0)
+#define MAPV5_HDRINFO_HDR_TYPE_FMASK	GENMASK(7, 1)
+#define MAPV5_CSUMINFO_VALID_FLAG	BIT(7)
+
+#define RMNET_MAP_HEADER_TYPE_CSUM_OFFLOAD 2
 #endif /* !(_LINUX_IF_RMNET_H_) */

On 2021-05-29 04:41, Jakub Kicinski wrote:

On Thu, 27 May 2021 14:18:42 +0530 Sharath Chandra Vurukala wrote:

quoted

Adding support for MAPv5 egress packets.

This involves adding the MAPv5 header and setting the 
csum_valid_required
in the checksum header to request HW compute the checksum.

Corresponding stats are incremented based on whether the checksum is
computed in software or HW.

New stat has been added which represents the count of packets whose
checksum is calculated by the HW.

Signed-off-by: Sharath Chandra Vurukala <redacted>

quoted

+static void rmnet_map_v5_checksum_uplink_packet(struct sk_buff *skb,
+						struct rmnet_port *port,
+						struct net_device *orig_dev)
+{
+	struct rmnet_priv *priv = netdev_priv(orig_dev);
+	struct rmnet_map_v5_csum_header *ul_header;
+
+	if (!(port->data_format & RMNET_FLAGS_EGRESS_MAP_CKSUMV5))
+		return;

how can we get here if this condition is not met? Looks like defensive
programming.

Yes we get here only for the MAPv5 case, as you think this is just a 
defensive code.
will remove this in next patch.

quoted

+	ul_header = skb_push(skb, sizeof(*ul_header));

Are you making sure you can modify head? I only see a check if there is
enough headroom but not if head is writable (skb_cow_head()).

TSkb_cow_head() changes will be done in the rmnet_map_egress_handler() 
in the next patch.

quoted

+	memset(ul_header, 0, sizeof(*ul_header));
+	ul_header->header_info = 
u8_encode_bits(RMNET_MAP_HEADER_TYPE_CSUM_OFFLOAD,
+						MAPV5_HDRINFO_HDR_TYPE_FMASK);

Is prepending the header required even when packet doesn't need
checksuming?

quoted

+	if (skb->ip_summed == CHECKSUM_PARTIAL) {
+		void *iph = (char *)ul_header + sizeof(*ul_header);

ip_hdr(skb)

quoted

+		__sum16 *check;
+		void *trans;
+		u8 proto;
+
+		if (skb->protocol == htons(ETH_P_IP)) {
+			u16 ip_len = ((struct iphdr *)iph)->ihl * 4;
+
+			proto = ((struct iphdr *)iph)->protocol;
+			trans = iph + ip_len;
+		} else if (skb->protocol == htons(ETH_P_IPV6)) {
+#if IS_ENABLED(CONFIG_IPV6)
+			u16 ip_len = sizeof(struct ipv6hdr);
+
+			proto = ((struct ipv6hdr *)iph)->nexthdr;
+			trans = iph + ip_len;
+#else
+			priv->stats.csum_err_invalid_ip_version++;
+			goto sw_csum;
+#endif /* CONFIG_IPV6 */
+		} else {
+			priv->stats.csum_err_invalid_ip_version++;
+			goto sw_csum;
+		}
+
+		check = rmnet_map_get_csum_field(proto, trans);
+		if (check) {
+			skb->ip_summed = CHECKSUM_NONE;
+			/* Ask for checksum offloading */
+			ul_header->csum_info |= MAPV5_CSUMINFO_VALID_FLAG;
+			priv->stats.csum_hw++;
+			return;

Please try to keep the success path unindented.

Sure will take care of these comments in next patch.

quoted

+		}
+	}
+
+sw_csum:
+	priv->stats.csum_sw++;
+}