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// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2013-2018, 2021, The Linux Foundation. All rights reserved.
*
* RMNET Data ingress/egress handler
*/
#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"
#include "rmnet_map.h"
#include "rmnet_handlers.h"
#define RMNET_IP_VERSION_4 0x40
#define RMNET_IP_VERSION_6 0x60
/* Helper Functions */
static void rmnet_set_skb_proto(struct sk_buff *skb)
{
switch (skb->data[0] & 0xF0) {
case RMNET_IP_VERSION_4:
skb->protocol = htons(ETH_P_IP);
break;
case RMNET_IP_VERSION_6:
skb->protocol = htons(ETH_P_IPV6);
break;
default:
skb->protocol = htons(ETH_P_MAP);
break;
}
}
/* Generic handler */
static void
rmnet_deliver_skb(struct sk_buff *skb)
{
struct rmnet_priv *priv = netdev_priv(skb->dev);
skb_reset_transport_header(skb);
skb_reset_network_header(skb);
rmnet_vnd_rx_fixup(skb, skb->dev);
skb->pkt_type = PACKET_HOST;
skb_set_mac_header(skb, 0);
gro_cells_receive(&priv->gro_cells, skb);
}
/* MAP handler */
static void
__rmnet_map_ingress_handler(struct sk_buff *skb,
struct rmnet_port *port)
{
struct rmnet_map_header *map_header = (void *)skb->data;
struct rmnet_endpoint *ep;
u16 len, pad;
u8 mux_id;
if (map_header->flags & MAP_CMD_FLAG) {
/* Packet contains a MAP command (not data) */
if (port->data_format & RMNET_FLAGS_INGRESS_MAP_COMMANDS)
return rmnet_map_command(skb, port);
goto free_skb;
}
mux_id = map_header->mux_id;
pad = map_header->flags & MAP_PAD_LEN_MASK;
len = ntohs(map_header->pkt_len) - pad;
if (mux_id >= RMNET_MAX_LOGICAL_EP)
goto free_skb;
ep = rmnet_get_endpoint(port, mux_id);
if (!ep)
goto free_skb;
skb->dev = ep->egress_dev;
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 {
/* Subtract MAP header */
skb_pull(skb, sizeof(*map_header));
rmnet_set_skb_proto(skb);
if (port->data_format & RMNET_FLAGS_INGRESS_MAP_CKSUMV4 &&
!rmnet_map_checksum_downlink_packet(skb, len + pad))
skb->ip_summed = CHECKSUM_UNNECESSARY;
}
skb_trim(skb, len);
rmnet_deliver_skb(skb);
return;
free_skb:
kfree_skb(skb);
}
static void
rmnet_map_ingress_handler(struct sk_buff *skb,
struct rmnet_port *port)
{
struct sk_buff *skbn;
if (skb->dev->type == ARPHRD_ETHER) {
if (pskb_expand_head(skb, ETH_HLEN, 0, GFP_ATOMIC)) {
kfree_skb(skb);
return;
}
skb_push(skb, ETH_HLEN);
}
if (port->data_format & RMNET_FLAGS_INGRESS_DEAGGREGATION) {
while ((skbn = rmnet_map_deaggregate(skb, port)) != NULL)
__rmnet_map_ingress_handler(skbn, port);
consume_skb(skb);
} else {
__rmnet_map_ingress_handler(skb, port);
}
}
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, csum_type = 0;
struct rmnet_map_header *map_header;
additional_header_len = 0;
required_headroom = sizeof(struct rmnet_map_header);
if (port->data_format & RMNET_FLAGS_EGRESS_MAP_CKSUMV4) {
additional_header_len = sizeof(struct rmnet_map_ul_csum_header);
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_cow_head(skb, required_headroom) < 0)
return -ENOMEM;
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,
port, 0);
if (!map_header)
return -ENOMEM;
map_header->mux_id = mux_id;
skb->protocol = htons(ETH_P_MAP);
return 0;
}
static void
rmnet_bridge_handler(struct sk_buff *skb, struct net_device *bridge_dev)
{
if (skb_mac_header_was_set(skb))
skb_push(skb, skb->mac_len);
if (bridge_dev) {
skb->dev = bridge_dev;
dev_queue_xmit(skb);
}
}
/* Ingress / Egress Entry Points */
/* Processes packet as per ingress data format for receiving device. Logical
* endpoint is determined from packet inspection. Packet is then sent to the
* egress device listed in the logical endpoint configuration.
*/
rx_handler_result_t rmnet_rx_handler(struct sk_buff **pskb)
{
struct sk_buff *skb = *pskb;
struct rmnet_port *port;
struct net_device *dev;
if (!skb)
goto done;
if (skb_linearize(skb)) {
kfree_skb(skb);
goto done;
}
if (skb->pkt_type == PACKET_LOOPBACK)
return RX_HANDLER_PASS;
dev = skb->dev;
port = rmnet_get_port_rcu(dev);
if (unlikely(!port)) {
dev_core_stats_rx_nohandler_inc(skb->dev);
kfree_skb(skb);
goto done;
}
switch (port->rmnet_mode) {
case RMNET_EPMODE_VND:
rmnet_map_ingress_handler(skb, port);
break;
case RMNET_EPMODE_BRIDGE:
rmnet_bridge_handler(skb, port->bridge_ep);
break;
}
done:
return RX_HANDLER_CONSUMED;
}
/* Modifies packet as per logical endpoint configuration and egress data format
* for egress device configured in logical endpoint. Packet is then transmitted
* on the egress device.
*/
void rmnet_egress_handler(struct sk_buff *skb)
{
struct net_device *orig_dev;
struct rmnet_port *port;
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;
mux_id = priv->mux_id;
port = rmnet_get_port_rcu(skb->dev);
if (!port)
goto drop;
if (rmnet_map_egress_handler(skb, port, mux_id, orig_dev))
goto drop;
rmnet_vnd_tx_fixup(skb, orig_dev);
dev_queue_xmit(skb);
return;
drop:
this_cpu_inc(priv->pcpu_stats->stats.tx_drops);
kfree_skb(skb);
}
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