Re: [PATCH net-next v7 2/3] net: ethernet: rmnet: Support for ingress MAPv5 checksum offload
From: sharathv
Date: Tue Jun 01 2021 - 15:06:49 EST
On 2021-05-29 04:28, Jakub Kicinski wrote:
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 <sharathv@xxxxxxxxxxxxxx>
@@ -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.
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.
+ 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
+ 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.
+ }
+
+ 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?
*/
#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.
+/* 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.
Sure, will take care in next patch.
+ *
+ * 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_) */