[PATCH net-next 00/10] net: qualcomm: rmnet: Enable csum offloads

[PATCH net-next 00/10] net: qualcomm: rmnet: Enable csum offloads

[Subash Abhinov Kasiviswanathan]

This series introduces the MAPv4 packet format for checksum
offload plus some other minor changes.

Patches 1-3 are cleanups.

Patch 4 renames the ingress format to data format so that all data
formats can be configured using this going forward.

Patch 5 uses the pacing helper to improve TCP transmit performance.

Patch 6-9 defines the the MAPv4 for checksum offload for RX and TX.
A new header and trailer format are used as part of MAPv4.
For RX checksum offload, only the 1's complement of the IP payload
portion is computed by hardware. The meta data from RX header is
used to verify the checksum field in the packet. Note that the
IP packet and its field itself is not modified by hardware.
This gives metadata to help with the RX checksum. For TX, the
required metadata is filled up so hardware can compute the
checksum.

Patch 10 enables GSO on rmnet devices

Subash Abhinov Kasiviswanathan (10):
  net: qualcomm: rmnet: Remove redundant check when stamping map header
  net: qualcomm: rmnet: Remove invalid condition while stamping mux id
  net: qualcomm: rmnet: Remove unused function declaration
  net: qualcomm: rmnet: Rename ingress data format to data format
  net: qualcomm: rmnet: Set pacing rate
  net: qualcomm: rmnet: Define the MAPv4 packet formats
  net: qualcomm: rmnet: Add support for RX checksum offload
  net: qualcomm: rmnet: Handle command packets with checksum trailer
  net: qualcomm: rmnet: Add support for TX checksum offload
  net: qualcomm: rmnet: Add support for GSO

 drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c |  10 +-
 drivers/net/ethernet/qualcomm/rmnet/rmnet_config.h |   2 +-
 .../net/ethernet/qualcomm/rmnet/rmnet_handlers.c   |  36 ++-
 drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h    |  23 +-
 .../ethernet/qualcomm/rmnet/rmnet_map_command.c    |  17 +-
 .../net/ethernet/qualcomm/rmnet/rmnet_map_data.c   | 298 ++++++++++++++++++++-
 .../net/ethernet/qualcomm/rmnet/rmnet_private.h    |   2 +
 drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c    |   4 +
 8 files changed, 367 insertions(+), 25 deletions(-)

-- 
1.9.1

[PATCH net-next 01/10] net: qualcomm: rmnet: Remove redundant check when stamping map header

[Subash Abhinov Kasiviswanathan]

We already check the headroom once in rmnet_map_egress_handler(),
so this is not needed.

Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
---
 drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
index 86b8c75..978ce26 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
@@ -32,9 +32,6 @@ struct rmnet_map_header *rmnet_map_add_map_header(struct sk_buff *skb,
 	u32 padding, map_datalen;
 	u8 *padbytes;
 
-	if (skb_headroom(skb) < sizeof(struct rmnet_map_header))
-		return NULL;
-
 	map_datalen = skb->len - hdrlen;
 	map_header = (struct rmnet_map_header *)
 			skb_push(skb, sizeof(struct rmnet_map_header));
-- 
1.9.1

[PATCH net-next 02/10] net: qualcomm: rmnet: Remove invalid condition while stamping mux id

[Subash Abhinov Kasiviswanathan]

rmnet devices cannot have a mux id of 255. This is validated when
assigning the mux id to the rmnet devices. As a result, checking for
mux id 255 does not apply in egress path.

Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
---
 drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c
index 0553932..b2d317e3 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c
@@ -143,10 +143,7 @@ static int rmnet_map_egress_handler(struct sk_buff *skb,
 	if (!map_header)
 		goto fail;
 
-	if (mux_id == 0xff)
-		map_header->mux_id = 0;
-	else
-		map_header->mux_id = mux_id;
+	map_header->mux_id = mux_id;
 
 	skb->protocol = htons(ETH_P_MAP);
 
-- 
1.9.1

[PATCH net-next 03/10] net: qualcomm: rmnet: Remove unused function declaration

[Subash Abhinov Kasiviswanathan]

rmnet_map_demultiplex() is only declared but not defined anywhere,
so remove it.

Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
---
 drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h
index 4df359d..ef0eff2 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h
@@ -67,7 +67,6 @@ struct rmnet_map_header {
 #define RMNET_MAP_NO_PAD_BYTES        0
 #define RMNET_MAP_ADD_PAD_BYTES       1
 
-u8 rmnet_map_demultiplex(struct sk_buff *skb);
 struct sk_buff *rmnet_map_deaggregate(struct sk_buff *skb);
 struct rmnet_map_header *rmnet_map_add_map_header(struct sk_buff *skb,
 						  int hdrlen, int pad);
-- 
1.9.1

[PATCH net-next 04/10] net: qualcomm: rmnet: Rename ingress data format to data format

[Subash Abhinov Kasiviswanathan]

This is done so that we can use this field for both ingress and
egress flags.

Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
---
 drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c   | 10 +++++-----
 drivers/net/ethernet/qualcomm/rmnet/rmnet_config.h   |  2 +-
 drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c |  5 ++---
 3 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c
index cedacdd..7e7704d 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c
@@ -143,7 +143,7 @@ static int rmnet_newlink(struct net *src_net, struct net_device *dev,
 			 struct nlattr *tb[], struct nlattr *data[],
 			 struct netlink_ext_ack *extack)
 {
-	int ingress_format = RMNET_INGRESS_FORMAT_DEAGGREGATION;
+	u32 data_format = RMNET_INGRESS_FORMAT_DEAGGREGATION;
 	struct net_device *real_dev;
 	int mode = RMNET_EPMODE_VND;
 	struct rmnet_endpoint *ep;
@@ -185,11 +185,11 @@ static int rmnet_newlink(struct net *src_net, struct net_device *dev,
 		struct ifla_vlan_flags *flags;
 
 		flags = nla_data(data[IFLA_VLAN_FLAGS]);
-		ingress_format = flags->flags & flags->mask;
+		data_format = flags->flags & flags->mask;
 	}
 
-	netdev_dbg(dev, "data format [ingress 0x%08X]\n", ingress_format);
-	port->ingress_data_format = ingress_format;
+	netdev_dbg(dev, "data format [0x%08X]\n", data_format);
+	port->data_format = data_format;
 
 	return 0;
 
@@ -353,7 +353,7 @@ static int rmnet_changelink(struct net_device *dev, struct nlattr *tb[],
 		struct ifla_vlan_flags *flags;
 
 		flags = nla_data(data[IFLA_VLAN_FLAGS]);
-		port->ingress_data_format = flags->flags & flags->mask;
+		port->data_format = flags->flags & flags->mask;
 	}
 
 	return 0;
diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.h b/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.h
index 2ea9fe3..00e4634 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.h
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.h
@@ -32,7 +32,7 @@ struct rmnet_endpoint {
  */
 struct rmnet_port {
 	struct net_device *dev;
-	u32 ingress_data_format;
+	u32 data_format;
 	u8 nr_rmnet_devs;
 	u8 rmnet_mode;
 	struct hlist_head muxed_ep[RMNET_MAX_LOGICAL_EP];
diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c
index b2d317e3..8e1f43a 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c
@@ -69,8 +69,7 @@ static void rmnet_set_skb_proto(struct sk_buff *skb)
 	u16 len;
 
 	if (RMNET_MAP_GET_CD_BIT(skb)) {
-		if (port->ingress_data_format
-		    & RMNET_INGRESS_FORMAT_MAP_COMMANDS)
+		if (port->data_format & RMNET_INGRESS_FORMAT_MAP_COMMANDS)
 			return rmnet_map_command(skb, port);
 
 		goto free_skb;
@@ -114,7 +113,7 @@ static void rmnet_set_skb_proto(struct sk_buff *skb)
 		skb_push(skb, ETH_HLEN);
 	}
 
-	if (port->ingress_data_format & RMNET_INGRESS_FORMAT_DEAGGREGATION) {
+	if (port->data_format & RMNET_INGRESS_FORMAT_DEAGGREGATION) {
 		while ((skbn = rmnet_map_deaggregate(skb)) != NULL)
 			__rmnet_map_ingress_handler(skbn, port);
 
-- 
1.9.1

[PATCH net-next 05/10] net: qualcomm: rmnet: Set pacing rate

[Subash Abhinov Kasiviswanathan]

With a default pacing rate of 10, the uplink data rate for a single
TCP stream is around 10Mbps. Setting it to 8 increases it to 146Mbps
which is the maximum supported transmit rate.

Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
---
 drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c
index 8e1f43a..8f8c4f2 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c
@@ -16,6 +16,7 @@
 #include <linux/netdevice.h>
 #include <linux/netdev_features.h>
 #include <linux/if_arp.h>
+#include <net/sock.h>
 #include "rmnet_private.h"
 #include "rmnet_config.h"
 #include "rmnet_vnd.h"
@@ -204,6 +205,8 @@ void rmnet_egress_handler(struct sk_buff *skb)
 	struct rmnet_priv *priv;
 	u8 mux_id;
 
+	sk_pacing_shift_update(skb->sk, 8);
+
 	orig_dev = skb->dev;
 	priv = netdev_priv(orig_dev);
 	skb->dev = priv->real_dev;
-- 
1.9.1

[PATCH net-next 06/10] net: qualcomm: rmnet: Define the MAPv4 packet formats

[Subash Abhinov Kasiviswanathan]

The MAPv4 packet format adds support for RX / TX checksum offload.
For a bi-directional UDP stream at a rate of 570 / 146 Mbps, roughly
10% CPU cycles are saved.

For receive path, there is a checksum trailer appended to the end of
the MAP packet. The valid field indicates if hardware has computed
the checksum. csum_start_offset indicates the offset from the start
of the IP header from which hardware has computed checksum.
csum_length is the number of bytes over which the checksum was
computed and the resulting value is csum_value.

In the transmit path, a header is appended between the end of the MAP
header and the start of the IP packet. csum_start_offset is the offset
in bytes from which hardware will compute the checksum if the
csum_enabled bit is set. udp_ip4_ind indicates if the checksum
value of 0 is valid or not. csum_insert_offset is the offset from the
csum_start_offset where hardware will insert the computed checksum.

The use of this additional packet format for checksum offload is
explained in subsequent patches.

Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
---
 drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h     | 16 ++++++++++++++++
 drivers/net/ethernet/qualcomm/rmnet/rmnet_private.h |  2 ++
 2 files changed, 18 insertions(+)

diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h
index ef0eff2..01d876c 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h
@@ -47,6 +47,22 @@ struct rmnet_map_header {
 	u16 pkt_len;
 }  __aligned(1);
 
+struct rmnet_map_dl_csum_trailer {
+	u8  reserved1;
+	u8  valid:1;
+	u8  reserved2:7;
+	u16 csum_start_offset;
+	u16 csum_length;
+	u16 csum_value;
+} __aligned(1);
+
+struct rmnet_map_ul_csum_header {
+	u16 csum_start_offset;
+	u16 csum_insert_offset:14;
+	u16 udp_ip4_ind:1;
+	u16 csum_enabled:1;
+} __aligned(1);
+
 #define RMNET_MAP_GET_MUX_ID(Y) (((struct rmnet_map_header *) \
 				 (Y)->data)->mux_id)
 #define RMNET_MAP_GET_CD_BIT(Y) (((struct rmnet_map_header *) \
diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_private.h b/drivers/net/ethernet/qualcomm/rmnet/rmnet_private.h
index d214280..de0143e 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_private.h
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_private.h
@@ -21,6 +21,8 @@
 /* Constants */
 #define RMNET_INGRESS_FORMAT_DEAGGREGATION      BIT(0)
 #define RMNET_INGRESS_FORMAT_MAP_COMMANDS       BIT(1)
+#define RMNET_INGRESS_FORMAT_MAP_CKSUMV4        BIT(2)
+#define RMNET_EGRESS_FORMAT_MAP_CKSUMV4         BIT(3)
 
 /* Replace skb->dev to a virtual rmnet device and pass up the stack */
 #define RMNET_EPMODE_VND (1)
-- 
1.9.1

[PATCH net-next 07/10] net: qualcomm: rmnet: Add support for RX checksum offload

[Subash Abhinov Kasiviswanathan]

When using the MAPv4 packet format, receive checksum offload can be
enabled in hardware. The checksum computation over pseudo header is
not offloaded but the rest of the checksum computation over
the payload is offloaded. This applies only for TCP / UDP packets
which are not fragmented.

rmnet validates the TCP/UDP checksum for the packet using the checksum
from the checksum trailer added to the packet by hardware. The
validation performed is as following -

1. Perform 1's complement over the checksum value from the trailer
2. Compute 1's complement checksum over IPv4 / IPv6 header and
   subtracts it from the value from step 1
3. Computes 1's complement checksum over IPv4 / IPv6 pseudo header and
   adds it to the value from step 2
4. Subtracts the checksum value from the TCP / UDP header from the
   value from step 3.
5. Compares the value from step 4 to the checksum value from the
   TCP / UDP header.
6. If the comparison in step 5 succeeds, CHECKSUM_UNNECESSARY is set
   and the packet is passed on to network stack. If there is a
   failure, then the packet is passed on as such without modifying
   the ip_summed field.

The checksum field is also checked for UDP checksum 0 as per RFC 768
and for unexpected TCP checksum of 0.

If checksum offload is disabled when using MAPv4 packet format in
receive path, the packet is queued as is to network stack without
the validations above.

Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
---
 .../net/ethernet/qualcomm/rmnet/rmnet_handlers.c   |  15 +-
 drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h    |   4 +-
 .../net/ethernet/qualcomm/rmnet/rmnet_map_data.c   | 177 ++++++++++++++++++++-
 drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c    |   2 +
 4 files changed, 192 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c
index 8f8c4f2..3409458 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c
@@ -66,8 +66,8 @@ static void rmnet_set_skb_proto(struct sk_buff *skb)
 			    struct rmnet_port *port)
 {
 	struct rmnet_endpoint *ep;
+	u16 len, pad;
 	u8 mux_id;
-	u16 len;
 
 	if (RMNET_MAP_GET_CD_BIT(skb)) {
 		if (port->data_format & RMNET_INGRESS_FORMAT_MAP_COMMANDS)
@@ -77,7 +77,8 @@ static void rmnet_set_skb_proto(struct sk_buff *skb)
 	}
 
 	mux_id = RMNET_MAP_GET_MUX_ID(skb);
-	len = RMNET_MAP_GET_LENGTH(skb) - RMNET_MAP_GET_PAD(skb);
+	pad = RMNET_MAP_GET_PAD(skb);
+	len = RMNET_MAP_GET_LENGTH(skb) - pad;
 
 	if (mux_id >= RMNET_MAX_LOGICAL_EP)
 		goto free_skb;
@@ -90,8 +91,14 @@ static void rmnet_set_skb_proto(struct sk_buff *skb)
 
 	/* Subtract MAP header */
 	skb_pull(skb, sizeof(struct rmnet_map_header));
-	skb_trim(skb, len);
 	rmnet_set_skb_proto(skb);
+
+	if (port->data_format & RMNET_INGRESS_FORMAT_MAP_CKSUMV4) {
+		if (!rmnet_map_checksum_downlink_packet(skb, len + pad))
+			skb->ip_summed = CHECKSUM_UNNECESSARY;
+	}
+
+	skb_trim(skb, len);
 	rmnet_deliver_skb(skb);
 	return;
 
@@ -115,7 +122,7 @@ static void rmnet_set_skb_proto(struct sk_buff *skb)
 	}
 
 	if (port->data_format & RMNET_INGRESS_FORMAT_DEAGGREGATION) {
-		while ((skbn = rmnet_map_deaggregate(skb)) != NULL)
+		while ((skbn = rmnet_map_deaggregate(skb, port)) != NULL)
 			__rmnet_map_ingress_handler(skbn, port);
 
 		consume_skb(skb);
diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h
index 01d876c..0539d99 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h
@@ -83,9 +83,11 @@ struct rmnet_map_ul_csum_header {
 #define RMNET_MAP_NO_PAD_BYTES        0
 #define RMNET_MAP_ADD_PAD_BYTES       1
 
-struct sk_buff *rmnet_map_deaggregate(struct sk_buff *skb);
+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);
 void rmnet_map_command(struct sk_buff *skb, struct rmnet_port *port);
+int rmnet_map_checksum_downlink_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 978ce26..543e423 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
@@ -14,6 +14,9 @@
  */
 
 #include <linux/netdevice.h>
+#include <linux/ip.h>
+#include <linux/ipv6.h>
+#include <net/ip6_checksum.h>
 #include "rmnet_config.h"
 #include "rmnet_map.h"
 #include "rmnet_private.h"
@@ -21,6 +24,144 @@
 #define RMNET_MAP_DEAGGR_SPACING  64
 #define RMNET_MAP_DEAGGR_HEADROOM (RMNET_MAP_DEAGGR_SPACING / 2)
 
+static u16 *rmnet_map_get_csum_field(unsigned char protocol,
+				     const void *txporthdr)
+{
+	u16 *check = 0;
+
+	switch (protocol) {
+	case IPPROTO_TCP:
+		check = &(((struct tcphdr *)txporthdr)->check);
+		break;
+
+	case IPPROTO_UDP:
+		check = &(((struct udphdr *)txporthdr)->check);
+		break;
+
+	default:
+		check = 0;
+		break;
+	}
+
+	return check;
+}
+
+static int
+rmnet_map_ipv4_dl_csum_trailer(struct sk_buff *skb,
+			       struct rmnet_map_dl_csum_trailer *csum_trailer)
+{
+	u16 ip_pseudo_payload_csum, pseudo_csum, ip_hdr_csum, *csum_field;
+	u16 csum_value, ip_payload_csum, csum_value_final;
+	struct iphdr *ip4h;
+	void *txporthdr;
+
+	ip4h = (struct iphdr *)(skb->data);
+	if ((ntohs(ip4h->frag_off) & IP_MF) ||
+	    ((ntohs(ip4h->frag_off) & IP_OFFSET) > 0))
+		return -EOPNOTSUPP;
+
+	txporthdr = skb->data + ip4h->ihl * 4;
+
+	csum_field = rmnet_map_get_csum_field(ip4h->protocol, txporthdr);
+
+	if (!csum_field)
+		return -EPROTONOSUPPORT;
+
+	/* RFC 768 - Skip IPv4 UDP packets where sender checksum field is 0 */
+	if (*csum_field == 0 && ip4h->protocol == IPPROTO_UDP)
+		return 0;
+
+	csum_value = ~ntohs(csum_trailer->csum_value);
+	ip_hdr_csum = ~ip_fast_csum(ip4h, (int)ip4h->ihl);
+	ip_payload_csum = csum16_sub(csum_value, ip_hdr_csum);
+
+	pseudo_csum = ~ntohs(csum_tcpudp_magic(ip4h->saddr, ip4h->daddr,
+			     (u16)(ntohs(ip4h->tot_len) - ip4h->ihl * 4),
+			     (u16)ip4h->protocol, 0));
+	ip_pseudo_payload_csum = csum16_add(ip_payload_csum, pseudo_csum);
+
+	csum_value_final = ~csum16_sub(ip_pseudo_payload_csum,
+				       ntohs(*csum_field));
+
+	if (unlikely(csum_value_final == 0)) {
+		switch (ip4h->protocol) {
+		case IPPROTO_UDP:
+			/* RFC 768 - DL4 1's complement rule for UDP csum 0 */
+			csum_value_final = ~csum_value_final;
+			break;
+
+		case IPPROTO_TCP:
+			/* DL4 Non-RFC compliant TCP checksum found */
+			if (*csum_field == 0xFFFF)
+				csum_value_final = ~csum_value_final;
+			break;
+		}
+	}
+
+	if (csum_value_final == ntohs(*csum_field))
+		return 0;
+	else
+		return -EINVAL;
+}
+
+#if IS_ENABLED(CONFIG_IPV6)
+static int
+rmnet_map_ipv6_dl_csum_trailer(struct sk_buff *skb,
+			       struct rmnet_map_dl_csum_trailer *csum_trailer)
+{
+	u16 ip_pseudo_payload_csum, pseudo_csum, ip6_hdr_csum, *csum_field;
+	u16 csum_value, ip6_payload_csum, csum_value_final;
+	struct ipv6hdr *ip6h;
+	void *txporthdr;
+	u32 length;
+
+	ip6h = (struct ipv6hdr *)(skb->data);
+
+	txporthdr = skb->data + sizeof(struct ipv6hdr);
+	csum_field = rmnet_map_get_csum_field(ip6h->nexthdr, txporthdr);
+
+	if (!csum_field)
+		return -EPROTONOSUPPORT;
+
+	csum_value = ~ntohs(csum_trailer->csum_value);
+	ip6_hdr_csum = ~ntohs(ip_compute_csum(ip6h,
+			      (int)(txporthdr - (void *)(skb->data))));
+	ip6_payload_csum = csum16_sub(csum_value, ip6_hdr_csum);
+
+	length = (ip6h->nexthdr == IPPROTO_UDP) ?
+		 ntohs(((struct udphdr *)txporthdr)->len) :
+		 ntohs(ip6h->payload_len);
+	pseudo_csum = ~ntohs(csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
+			     length, ip6h->nexthdr, 0));
+	ip_pseudo_payload_csum = csum16_add(ip6_payload_csum, pseudo_csum);
+
+	csum_value_final = ~csum16_sub(ip_pseudo_payload_csum,
+				       ntohs(*csum_field));
+
+	if (unlikely(csum_value_final == 0)) {
+		switch (ip6h->nexthdr) {
+		case IPPROTO_UDP:
+			/* RFC 2460 section 8.1
+			 * DL6 One's complement rule for UDP checksum 0
+			 */
+			csum_value_final = ~csum_value_final;
+			break;
+
+		case IPPROTO_TCP:
+			/* DL6 Non-RFC compliant TCP checksum found */
+			if (*csum_field == 0xFFFF)
+				csum_value_final = ~csum_value_final;
+			break;
+		}
+	}
+
+	if (csum_value_final == ntohs(*csum_field))
+		return 0;
+	else
+		return -EINVAL;
+}
+#endif
+
 /* Adds MAP header to front of skb->data
  * Padding is calculated and set appropriately in MAP header. Mux ID is
  * initialized to 0.
@@ -66,7 +207,8 @@ struct rmnet_map_header *rmnet_map_add_map_header(struct sk_buff *skb,
  * returned, indicating that there are no more packets to deaggregate. Caller
  * is responsible for freeing the original skb.
  */
-struct sk_buff *rmnet_map_deaggregate(struct sk_buff *skb)
+struct sk_buff *rmnet_map_deaggregate(struct sk_buff *skb,
+				      struct rmnet_port *port)
 {
 	struct rmnet_map_header *maph;
 	struct sk_buff *skbn;
@@ -78,6 +220,9 @@ struct sk_buff *rmnet_map_deaggregate(struct sk_buff *skb)
 	maph = (struct rmnet_map_header *)skb->data;
 	packet_len = ntohs(maph->pkt_len) + sizeof(struct rmnet_map_header);
 
+	if (port->data_format & RMNET_INGRESS_FORMAT_MAP_CKSUMV4)
+		packet_len += sizeof(struct rmnet_map_dl_csum_trailer);
+
 	if (((int)skb->len - (int)packet_len) < 0)
 		return NULL;
 
@@ -97,3 +242,33 @@ struct sk_buff *rmnet_map_deaggregate(struct sk_buff *skb)
 
 	return skbn;
 }
+
+/* Validates packet checksums. Function takes a pointer to
+ * the beginning of a buffer which contains the IP payload +
+ * padding + checksum trailer.
+ * Only IPv4 and IPv6 are supported along with TCP & UDP.
+ * Fragmented or tunneled packets are not supported.
+ */
+int rmnet_map_checksum_downlink_packet(struct sk_buff *skb, u16 len)
+{
+	struct rmnet_map_dl_csum_trailer *csum_trailer;
+
+	if (unlikely(!(skb->dev->features & NETIF_F_RXCSUM)))
+		return -EOPNOTSUPP;
+
+	csum_trailer = (struct rmnet_map_dl_csum_trailer *)(skb->data + len);
+
+	if (!ntohs(csum_trailer->valid))
+		return -EINVAL;
+
+	if (skb->protocol == htons(ETH_P_IP))
+		return rmnet_map_ipv4_dl_csum_trailer(skb, csum_trailer);
+	else if (skb->protocol == htons(ETH_P_IPV6))
+#if IS_ENABLED(CONFIG_IPV6)
+		return rmnet_map_ipv6_dl_csum_trailer(skb, csum_trailer);
+#else
+		return -EPROTONOSUPPORT;
+#endif
+
+	return 0;
+}
diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c
index 5bb29f4..879a2e0 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c
@@ -188,6 +188,8 @@ int rmnet_vnd_newlink(u8 id, struct net_device *rmnet_dev,
 	if (rmnet_get_endpoint(port, id))
 		return -EBUSY;
 
+	rmnet_dev->hw_features = NETIF_F_RXCSUM;
+
 	rc = register_netdevice(rmnet_dev);
 	if (!rc) {
 		ep->egress_dev = rmnet_dev;
-- 
1.9.1

[PATCH net-next 08/10] net: qualcomm: rmnet: Handle command packets with checksum trailer

[Subash Abhinov Kasiviswanathan]

When using the MAPv4 packet format in conjunction with MAP commands,
a dummy DL checksum trailer will be appended to the packet. Before
this packet is sent out as an ACK, the DL checksum trailer needs to be
removed.

Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
---
 drivers/net/ethernet/qualcomm/rmnet/rmnet_map_command.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_command.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_command.c
index 51e6049..6bc328f 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_command.c
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_command.c
@@ -58,11 +58,24 @@ static u8 rmnet_map_do_flow_control(struct sk_buff *skb,
 }
 
 static void rmnet_map_send_ack(struct sk_buff *skb,
-			       unsigned char type)
+			       unsigned char type,
+			       struct rmnet_port *port)
 {
 	struct rmnet_map_control_command *cmd;
 	int xmit_status;
 
+	if (port->data_format & RMNET_INGRESS_FORMAT_MAP_CKSUMV4) {
+		if (skb->len < sizeof(struct rmnet_map_header) +
+		    RMNET_MAP_GET_LENGTH(skb) +
+		    sizeof(struct rmnet_map_dl_csum_trailer)) {
+			kfree_skb(skb);
+			return;
+		}
+
+		skb_trim(skb, skb->len -
+			 sizeof(struct rmnet_map_dl_csum_trailer));
+	}
+
 	skb->protocol = htons(ETH_P_MAP);
 
 	cmd = RMNET_MAP_GET_CMD_START(skb);
@@ -100,5 +113,5 @@ void rmnet_map_command(struct sk_buff *skb, struct rmnet_port *port)
 		break;
 	}
 	if (rc == RMNET_MAP_COMMAND_ACK)
-		rmnet_map_send_ack(skb, rc);
+		rmnet_map_send_ack(skb, rc, port);
 }
-- 
1.9.1

[PATCH net-next 09/10] net: qualcomm: rmnet: Add support for TX checksum offload

[Subash Abhinov Kasiviswanathan]

TX checksum offload applies to TCP / UDP packets which are not
fragmented using the MAPv4 checksum header. The following needs to be
done to have checksum computed in hardware -

1. Set the checksum start offset and inset offset.
2. Set the csum_enabled bit
3. Compute and set 1's complement of partial checksum field in
   transport header.

If TX checksum offload is disabled, all the fields in the checksum
header are set 0 and hardware will not perform any computation.

Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
---
 .../net/ethernet/qualcomm/rmnet/rmnet_handlers.c   |   8 ++
 drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h    |   2 +
 .../net/ethernet/qualcomm/rmnet/rmnet_map_data.c   | 118 +++++++++++++++++++++
 drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c    |   1 +
 4 files changed, 129 insertions(+)

diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c
index 3409458..601edec 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c
@@ -141,11 +141,19 @@ static int rmnet_map_egress_handler(struct sk_buff *skb,
 	additional_header_len = 0;
 	required_headroom = sizeof(struct rmnet_map_header);
 
+	if (port->data_format & RMNET_EGRESS_FORMAT_MAP_CKSUMV4) {
+		additional_header_len = sizeof(struct rmnet_map_ul_csum_header);
+		required_headroom += additional_header_len;
+	}
+
 	if (skb_headroom(skb) < required_headroom) {
 		if (pskb_expand_head(skb, required_headroom, 0, GFP_KERNEL))
 			goto fail;
 	}
 
+	if (port->data_format & RMNET_EGRESS_FORMAT_MAP_CKSUMV4)
+		rmnet_map_checksum_uplink_packet(skb, orig_dev);
+
 	map_header = rmnet_map_add_map_header(skb, additional_header_len, 0);
 	if (!map_header)
 		goto fail;
diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h
index 0539d99..c635dd7 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h
@@ -89,5 +89,7 @@ struct rmnet_map_header *rmnet_map_add_map_header(struct sk_buff *skb,
 						  int hdrlen, 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);
 
 #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 543e423..56923a5 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
@@ -162,6 +162,84 @@ static u16 *rmnet_map_get_csum_field(unsigned char protocol,
 }
 #endif
 
+static void rmnet_map_complement_ipv4_txporthdr_csum_field(void *iphdr)
+{
+	struct iphdr *ip4h = (struct iphdr *)iphdr;
+	void *txphdr;
+	u16 *csum;
+
+	txphdr = iphdr + ip4h->ihl * 4;
+
+	if (ip4h->protocol == IPPROTO_TCP || ip4h->protocol == IPPROTO_UDP) {
+		csum = (u16 *)rmnet_map_get_csum_field(ip4h->protocol, txphdr);
+		*csum = ~(*csum);
+	}
+}
+
+static void
+rmnet_map_ipv4_ul_csum_header(void *iphdr,
+			      struct rmnet_map_ul_csum_header *ul_header,
+			      struct sk_buff *skb)
+{
+	struct iphdr *ip4h = (struct iphdr *)iphdr;
+	u16 *hdr = (u16 *)ul_header;
+
+	ul_header->csum_start_offset = htons((u16)(skb_transport_header(skb) -
+						   (unsigned char *)iphdr));
+	ul_header->csum_insert_offset = skb->csum_offset;
+	ul_header->csum_enabled = 1;
+	if (ip4h->protocol == IPPROTO_UDP)
+		ul_header->udp_ip4_ind = 1;
+	else
+		ul_header->udp_ip4_ind = 0;
+
+	/* Changing remaining fields to network order */
+	hdr++;
+	*hdr = htons(*hdr);
+
+	skb->ip_summed = CHECKSUM_NONE;
+
+	rmnet_map_complement_ipv4_txporthdr_csum_field(iphdr);
+}
+
+#if IS_ENABLED(CONFIG_IPV6)
+static void rmnet_map_complement_ipv6_txporthdr_csum_field(void *ip6hdr)
+{
+	struct ipv6hdr *ip6h = (struct ipv6hdr *)ip6hdr;
+	void *txphdr;
+	u16 *csum;
+
+	txphdr = ip6hdr + sizeof(struct ipv6hdr);
+
+	if (ip6h->nexthdr == IPPROTO_TCP || ip6h->nexthdr == IPPROTO_UDP) {
+		csum = (u16 *)rmnet_map_get_csum_field(ip6h->nexthdr, txphdr);
+		*csum = ~(*csum);
+	}
+}
+
+static void
+rmnet_map_ipv6_ul_csum_header(void *ip6hdr,
+			      struct rmnet_map_ul_csum_header *ul_header,
+			      struct sk_buff *skb)
+{
+	u16 *hdr = (u16 *)ul_header;
+
+	ul_header->csum_start_offset = htons((u16)(skb_transport_header(skb) -
+						   (unsigned char *)ip6hdr));
+	ul_header->csum_insert_offset = skb->csum_offset;
+	ul_header->csum_enabled = 1;
+	ul_header->udp_ip4_ind = 0;
+
+	/* Changing remaining fields to network order */
+	hdr++;
+	*hdr = htons(*hdr);
+
+	skb->ip_summed = CHECKSUM_NONE;
+
+	rmnet_map_complement_ipv6_txporthdr_csum_field(ip6hdr);
+}
+#endif
+
 /* Adds MAP header to front of skb->data
  * Padding is calculated and set appropriately in MAP header. Mux ID is
  * initialized to 0.
@@ -272,3 +350,43 @@ 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)
+{
+	struct rmnet_map_ul_csum_header *ul_header;
+	void *iphdr;
+
+	ul_header = (struct rmnet_map_ul_csum_header *)
+		    skb_push(skb, sizeof(struct rmnet_map_ul_csum_header));
+
+	if (unlikely(!(orig_dev->features &
+		     (NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM))))
+		goto sw_csum;
+
+	if (skb->ip_summed == CHECKSUM_PARTIAL) {
+		iphdr = (char *)ul_header +
+			sizeof(struct rmnet_map_ul_csum_header);
+
+		if (skb->protocol == htons(ETH_P_IP)) {
+			rmnet_map_ipv4_ul_csum_header(iphdr, ul_header, skb);
+			return;
+		} else if (skb->protocol == htons(ETH_P_IPV6)) {
+#if IS_ENABLED(CONFIG_IPV6)
+			rmnet_map_ipv6_ul_csum_header(iphdr, ul_header, skb);
+			return;
+#else
+			goto sw_csum;
+#endif
+		}
+	}
+
+sw_csum:
+	ul_header->csum_start_offset = 0;
+	ul_header->csum_insert_offset = 0;
+	ul_header->csum_enabled = 0;
+	ul_header->udp_ip4_ind = 0;
+}
diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c
index 879a2e0..f7f57ce 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c
@@ -189,6 +189,7 @@ int rmnet_vnd_newlink(u8 id, struct net_device *rmnet_dev,
 		return -EBUSY;
 
 	rmnet_dev->hw_features = NETIF_F_RXCSUM;
+	rmnet_dev->hw_features |= NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM;
 
 	rc = register_netdevice(rmnet_dev);
 	if (!rc) {
-- 
1.9.1

[PATCH net-next 10/10] net: qualcomm: rmnet: Add support for GSO

[Subash Abhinov Kasiviswanathan]

Real devices may support scatter gather(SG), so enable SG on rmnet
devices to use GSO. GSO reduces CPU cycles by 20% for a rate of
146Mpbs for a single stream TCP connection.

Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
---
 drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c
index f7f57ce..570a227 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c
@@ -190,6 +190,7 @@ int rmnet_vnd_newlink(u8 id, struct net_device *rmnet_dev,
 
 	rmnet_dev->hw_features = NETIF_F_RXCSUM;
 	rmnet_dev->hw_features |= NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM;
+	rmnet_dev->hw_features |= NETIF_F_SG;
 
 	rc = register_netdevice(rmnet_dev);
 	if (!rc) {
-- 
1.9.1

Re: [PATCH net-next 07/10] net: qualcomm: rmnet: Add support for RX checksum offload

[kbuild test robot]

Hi Subash,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on net-next/master]

url:    https://github.com/0day-ci/linux/commits/Subash-Abhinov-Kasiviswanathan/net-qualcomm-rmnet-Enable-csum-offloads/20171228-041216
reproduce:
        # apt-get install sparse
        make ARCH=x86_64 allmodconfig
        make C=1 CF=-D__CHECK_ENDIAN__


sparse warnings: (new ones prefixed by >>)


vim +30 drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c

    26	
    27	static u16 *rmnet_map_get_csum_field(unsigned char protocol,
    28					     const void *txporthdr)
    29	{
  > 30		u16 *check = 0;
    31	
    32		switch (protocol) {
    33		case IPPROTO_TCP:
  > 34			check = &(((struct tcphdr *)txporthdr)->check);
    35			break;
    36	
    37		case IPPROTO_UDP:
  > 38			check = &(((struct udphdr *)txporthdr)->check);
    39			break;
    40	
    41		default:
    42			check = 0;
    43			break;
    44		}
    45	
    46		return check;
    47	}
    48	
    49	static int
    50	rmnet_map_ipv4_dl_csum_trailer(struct sk_buff *skb,
    51				       struct rmnet_map_dl_csum_trailer *csum_trailer)
    52	{
    53		u16 ip_pseudo_payload_csum, pseudo_csum, ip_hdr_csum, *csum_field;
    54		u16 csum_value, ip_payload_csum, csum_value_final;
    55		struct iphdr *ip4h;
    56		void *txporthdr;
    57	
    58		ip4h = (struct iphdr *)(skb->data);
    59		if ((ntohs(ip4h->frag_off) & IP_MF) ||
    60		    ((ntohs(ip4h->frag_off) & IP_OFFSET) > 0))
    61			return -EOPNOTSUPP;
    62	
    63		txporthdr = skb->data + ip4h->ihl * 4;
    64	
    65		csum_field = rmnet_map_get_csum_field(ip4h->protocol, txporthdr);
    66	
    67		if (!csum_field)
    68			return -EPROTONOSUPPORT;
    69	
    70		/* RFC 768 - Skip IPv4 UDP packets where sender checksum field is 0 */
    71		if (*csum_field == 0 && ip4h->protocol == IPPROTO_UDP)
    72			return 0;
    73	
  > 74		csum_value = ~ntohs(csum_trailer->csum_value);
  > 75		ip_hdr_csum = ~ip_fast_csum(ip4h, (int)ip4h->ihl);
  > 76		ip_payload_csum = csum16_sub(csum_value, ip_hdr_csum);
    77	
  > 78		pseudo_csum = ~ntohs(csum_tcpudp_magic(ip4h->saddr, ip4h->daddr,
    79				     (u16)(ntohs(ip4h->tot_len) - ip4h->ihl * 4),
    80				     (u16)ip4h->protocol, 0));
  > 81		ip_pseudo_payload_csum = csum16_add(ip_payload_csum, pseudo_csum);
    82	
  > 83		csum_value_final = ~csum16_sub(ip_pseudo_payload_csum,
  > 84					       ntohs(*csum_field));
    85	
    86		if (unlikely(csum_value_final == 0)) {
    87			switch (ip4h->protocol) {
    88			case IPPROTO_UDP:
    89				/* RFC 768 - DL4 1's complement rule for UDP csum 0 */
    90				csum_value_final = ~csum_value_final;
    91				break;
    92	
    93			case IPPROTO_TCP:
    94				/* DL4 Non-RFC compliant TCP checksum found */
    95				if (*csum_field == 0xFFFF)
    96					csum_value_final = ~csum_value_final;
    97				break;
    98			}
    99		}
   100	
   101		if (csum_value_final == ntohs(*csum_field))
   102			return 0;
   103		else
   104			return -EINVAL;
   105	}
   106	
   107	#if IS_ENABLED(CONFIG_IPV6)
   108	static int
   109	rmnet_map_ipv6_dl_csum_trailer(struct sk_buff *skb,
   110				       struct rmnet_map_dl_csum_trailer *csum_trailer)
   111	{
   112		u16 ip_pseudo_payload_csum, pseudo_csum, ip6_hdr_csum, *csum_field;
   113		u16 csum_value, ip6_payload_csum, csum_value_final;
   114		struct ipv6hdr *ip6h;
   115		void *txporthdr;
   116		u32 length;
   117	
   118		ip6h = (struct ipv6hdr *)(skb->data);
   119	
   120		txporthdr = skb->data + sizeof(struct ipv6hdr);
   121		csum_field = rmnet_map_get_csum_field(ip6h->nexthdr, txporthdr);
   122	
   123		if (!csum_field)
   124			return -EPROTONOSUPPORT;
   125	
   126		csum_value = ~ntohs(csum_trailer->csum_value);
 > 127		ip6_hdr_csum = ~ntohs(ip_compute_csum(ip6h,
   128				      (int)(txporthdr - (void *)(skb->data))));
 > 129		ip6_payload_csum = csum16_sub(csum_value, ip6_hdr_csum);
   130	
   131		length = (ip6h->nexthdr == IPPROTO_UDP) ?
   132			 ntohs(((struct udphdr *)txporthdr)->len) :
   133			 ntohs(ip6h->payload_len);
   134		pseudo_csum = ~ntohs(csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
   135				     length, ip6h->nexthdr, 0));
   136		ip_pseudo_payload_csum = csum16_add(ip6_payload_csum, pseudo_csum);
   137	
   138		csum_value_final = ~csum16_sub(ip_pseudo_payload_csum,
   139					       ntohs(*csum_field));
   140	
   141		if (unlikely(csum_value_final == 0)) {
   142			switch (ip6h->nexthdr) {
   143			case IPPROTO_UDP:
   144				/* RFC 2460 section 8.1
   145				 * DL6 One's complement rule for UDP checksum 0
   146				 */
   147				csum_value_final = ~csum_value_final;
   148				break;
   149	
   150			case IPPROTO_TCP:
   151				/* DL6 Non-RFC compliant TCP checksum found */
   152				if (*csum_field == 0xFFFF)
   153					csum_value_final = ~csum_value_final;
   154				break;
   155			}
   156		}
   157	
   158		if (csum_value_final == ntohs(*csum_field))
   159			return 0;
   160		else
   161			return -EINVAL;
   162	}
   163	#endif
   164	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

Re: [PATCH net-next 09/10] net: qualcomm: rmnet: Add support for TX checksum offload

[kbuild test robot]

Hi Subash,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on net-next/master]

url:    https://github.com/0day-ci/linux/commits/Subash-Abhinov-Kasiviswanathan/net-qualcomm-rmnet-Enable-csum-offloads/20171228-041216
reproduce:
        # apt-get install sparse
        make ARCH=x86_64 allmodconfig
        make C=1 CF=-D__CHECK_ENDIAN__


sparse warnings: (new ones prefixed by >>)


vim +187 drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c

   106	
   107	#if IS_ENABLED(CONFIG_IPV6)
   108	static int
   109	rmnet_map_ipv6_dl_csum_trailer(struct sk_buff *skb,
   110				       struct rmnet_map_dl_csum_trailer *csum_trailer)
   111	{
   112		u16 ip_pseudo_payload_csum, pseudo_csum, ip6_hdr_csum, *csum_field;
   113		u16 csum_value, ip6_payload_csum, csum_value_final;
   114		struct ipv6hdr *ip6h;
   115		void *txporthdr;
   116		u32 length;
   117	
   118		ip6h = (struct ipv6hdr *)(skb->data);
   119	
   120		txporthdr = skb->data + sizeof(struct ipv6hdr);
   121		csum_field = rmnet_map_get_csum_field(ip6h->nexthdr, txporthdr);
   122	
   123		if (!csum_field)
   124			return -EPROTONOSUPPORT;
   125	
   126		csum_value = ~ntohs(csum_trailer->csum_value);
   127		ip6_hdr_csum = ~ntohs(ip_compute_csum(ip6h,
   128				      (int)(txporthdr - (void *)(skb->data))));
   129		ip6_payload_csum = csum16_sub(csum_value, ip6_hdr_csum);
   130	
   131		length = (ip6h->nexthdr == IPPROTO_UDP) ?
   132			 ntohs(((struct udphdr *)txporthdr)->len) :
   133			 ntohs(ip6h->payload_len);
   134		pseudo_csum = ~ntohs(csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
   135				     length, ip6h->nexthdr, 0));
   136		ip_pseudo_payload_csum = csum16_add(ip6_payload_csum, pseudo_csum);
   137	
 > 138		csum_value_final = ~csum16_sub(ip_pseudo_payload_csum,
 > 139					       ntohs(*csum_field));
   140	
   141		if (unlikely(csum_value_final == 0)) {
   142			switch (ip6h->nexthdr) {
   143			case IPPROTO_UDP:
   144				/* RFC 2460 section 8.1
   145				 * DL6 One's complement rule for UDP checksum 0
   146				 */
   147				csum_value_final = ~csum_value_final;
   148				break;
   149	
   150			case IPPROTO_TCP:
   151				/* DL6 Non-RFC compliant TCP checksum found */
   152				if (*csum_field == 0xFFFF)
   153					csum_value_final = ~csum_value_final;
   154				break;
   155			}
   156		}
   157	
   158		if (csum_value_final == ntohs(*csum_field))
   159			return 0;
   160		else
   161			return -EINVAL;
   162	}
   163	#endif
   164	
   165	static void rmnet_map_complement_ipv4_txporthdr_csum_field(void *iphdr)
   166	{
   167		struct iphdr *ip4h = (struct iphdr *)iphdr;
   168		void *txphdr;
   169		u16 *csum;
   170	
   171		txphdr = iphdr + ip4h->ihl * 4;
   172	
   173		if (ip4h->protocol == IPPROTO_TCP || ip4h->protocol == IPPROTO_UDP) {
   174			csum = (u16 *)rmnet_map_get_csum_field(ip4h->protocol, txphdr);
   175			*csum = ~(*csum);
   176		}
   177	}
   178	
   179	static void
   180	rmnet_map_ipv4_ul_csum_header(void *iphdr,
   181				      struct rmnet_map_ul_csum_header *ul_header,
   182				      struct sk_buff *skb)
   183	{
   184		struct iphdr *ip4h = (struct iphdr *)iphdr;
   185		u16 *hdr = (u16 *)ul_header;
   186	
 > 187		ul_header->csum_start_offset = htons((u16)(skb_transport_header(skb) -
   188							   (unsigned char *)iphdr));
   189		ul_header->csum_insert_offset = skb->csum_offset;
   190		ul_header->csum_enabled = 1;
   191		if (ip4h->protocol == IPPROTO_UDP)
   192			ul_header->udp_ip4_ind = 1;
   193		else
   194			ul_header->udp_ip4_ind = 0;
   195	
   196		/* Changing remaining fields to network order */
   197		hdr++;
 > 198		*hdr = htons(*hdr);
   199	
   200		skb->ip_summed = CHECKSUM_NONE;
   201	
   202		rmnet_map_complement_ipv4_txporthdr_csum_field(iphdr);
   203	}
   204	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation