// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2013-2018, 2021, The Linux Foundation. All rights reserved.
*
* RMNET Data MAP protocol
*/
#include <linux/netdevice.h>
#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"
#include "rmnet_vnd.h"
#define RMNET_MAP_DEAGGR_SPACING 64
#define RMNET_MAP_DEAGGR_HEADROOM (RMNET_MAP_DEAGGR_SPACING / 2)
static __sum16 *rmnet_map_get_csum_field(unsigned char protocol,
const void *txporthdr)
{
if (protocol == IPPROTO_TCP)
return &((struct tcphdr *)txporthdr)->check;
if (protocol == IPPROTO_UDP)
return &((struct udphdr *)txporthdr)->check;
return NULL;
}
static int
rmnet_map_ipv4_dl_csum_trailer(struct sk_buff *skb,
struct rmnet_map_dl_csum_trailer *csum_trailer,
struct rmnet_priv *priv)
{
struct iphdr *ip4h = (struct iphdr *)skb->data;
void *txporthdr = skb->data + ip4h->ihl * 4;
__sum16 *csum_field, pseudo_csum;
__sum16 ip_payload_csum;
/* Computing the checksum over just the IPv4 header--including its
* checksum field--should yield 0. If it doesn't, the IP header
* is bad, so return an error and let the IP layer drop it.
*/
if (ip_fast_csum(ip4h, ip4h->ihl)) {
priv->stats.csum_ip4_header_bad++;
return -EINVAL;
}
/* We don't support checksum offload on IPv4 fragments */
if (ip_is_fragment(ip4h)) {
priv->stats.csum_fragmented_pkt++;
return -EOPNOTSUPP;
}
/* Checksum offload is only supported for UDP and TCP protocols */
csum_field = rmnet_map_get_csum_field(ip4h->protocol, txporthdr);
if (!csum_field) {
priv->stats.csum_err_invalid_transport++;
return -EPROTONOSUPPORT;
}
/* RFC 768: UDP checksum is optional for IPv4, and is 0 if unused */
if (!*csum_field && ip4h->protocol == IPPROTO_UDP) {
priv->stats.csum_skipped++;
return 0;
}
/* The checksum value in the trailer is computed over the entire
* IP packet, including the IP header and payload. To derive the
* transport checksum from this, we first subract the contribution
* of the IP header from the trailer checksum. We then add the
* checksum computed over the pseudo header.
*
* We verified above that the IP header contributes zero to the
* trailer checksum. Therefore the checksum in the trailer is
* just the checksum computed over the IP payload.
* If the IP payload arrives intact, adding the pseudo header
* checksum to the IP payload checksum will yield 0xffff (negative
* zero). This means the trailer checksum and the pseudo checksum
* are additive inverses of each other. Put another way, the
* message passes the checksum test if the trailer checksum value
* is the negated pseudo header checksum.
*
* Knowing this, we don't even need to examine the transport
* header checksum value; it is already accounted for in the
* checksum value found in the trailer.
*/
ip_payload_csum = csum_trailer->csum_value;
pseudo_csum = csum_tcpudp_magic(ip4h->saddr, ip4h->daddr,
ntohs(ip4h->tot_len) - ip4h->ihl * 4,
ip4h->protocol, 0);
/* The cast is required to ensure only the low 16 bits are examined */
if (ip_payload_csum != (__sum16)~pseudo_csum) {
priv->stats.csum_validation_failed++;
return -EINVAL;
}
priv->stats.csum_ok++;
return 0;
}
#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,
struct rmnet_priv *priv)
{
struct ipv6hdr *ip6h = (struct ipv6hdr *)skb->data;
void *txporthdr = skb->data + sizeof(*ip6h);
__sum16 *csum_field, pseudo_csum;
__sum16 ip6_payload_csum;
__be16 ip_header_csum;
/* Checksum offload is only supported for UDP and TCP protocols;
* the packet cannot include any IPv6 extension headers
*/
csum_field = rmnet_map_get_csum_field(ip6h->nexthdr, txporthdr);
if (!csum_field) {
priv->stats.csum_err_invalid_transport++;
return -EPROTONOSUPPORT;
}
/* The checksum value in the trailer is computed over the entire
* IP packet, including the IP header and payload. To derive the
* transport checksum from this, we first subract the contribution
* of the IP header from the trailer checksum. We then add the
* checksum computed over the pseudo header.
*/
ip_header_csum = (__force __be16)ip_fast_csum(ip6h, sizeof(*ip6h) / 4);
ip6_payload_csum = csum16_sub(csum_trailer->csum_value, ip_header_csum);
pseudo_csum = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
ntohs(ip6h->payload_len),
ip6h->nexthdr, 0);
/* It's sufficient to compare the IP payload checksum with the
* negated pseudo checksum to determine whether the packet
* checksum was good. (See further explanation in comments
* in rmnet_map_ipv4_dl_csum_trailer()).
*
* The cast is required to ensure only the low 16 bits are
* examined.
*/
if (ip6_payload_csum != (__sum16)~pseudo_csum) {
priv->stats.csum_validation_failed++;
return -EINVAL;
}
priv->stats.csum_ok++;
return 0;
}
#else
static int
rmnet_map_ipv6_dl_csum_trailer(struct sk_buff *skb,
struct rmnet_map_dl_csum_trailer *csum_trailer,
struct rmnet_priv *priv)
{
return 0;
}
#endif
static void rmnet_map_complement_ipv4_txporthdr_csum_field(struct iphdr *ip4h)
{
void *txphdr;
u16 *csum;
txphdr = (void *)ip4h + 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(struct iphdr *iphdr,
struct rmnet_map_ul_csum_header *ul_header,
struct sk_buff *skb)
{
u16 val;
val = MAP_CSUM_UL_ENABLED_FLAG;
if (iphdr->protocol == IPPROTO_UDP)
val |= MAP_CSUM_UL_UDP_FLAG;
val |= skb->csum_offset & MAP_CSUM_UL_OFFSET_MASK;
ul_header->csum_start_offset = htons(skb_network_header_len(skb));
ul_header->csum_info = htons(val);
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(struct ipv6hdr *ip6h)
{
void *txphdr;
u16 *csum;
txphdr = ip6h + 1;
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(struct ipv6hdr *ipv6hdr,
struct rmnet_map_ul_csum_header *ul_header,
struct sk_buff *skb)
{
u16 val;
val = MAP_CSUM_UL_ENABLED_FLAG;
if (ipv6hdr->nexthdr == IPPROTO_UDP)
val |= MAP_CSUM_UL_UDP_FLAG;
val |= skb->csum_offset & MAP_CSUM_UL_OFFSET_MASK;
ul_header->csum_start_offset = htons(skb_network_header_len(skb));
ul_header->csum_info = htons(val);
skb->ip_summed = CHECKSUM_NONE;
rmnet_map_complement_ipv6_txporthdr_csum_field(ipv6hdr);
}
#else
static void
rmnet_map_ipv6_ul_csum_header(void *ip6hdr,
struct rmnet_map_ul_csum_header *ul_header,
struct sk_buff *skb)
{
}
#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;
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 = 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 (IS_ENABLED(CONFIG_IPV6) &&
skb->protocol == htons(ETH_P_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;
}
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,
struct rmnet_port *port,
int pad)
{
struct rmnet_map_header *map_header;
u32 padding, map_datalen;
map_datalen = skb->len - hdrlen;
map_header = (struct rmnet_map_header *)
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;
}
BUILD_BUG_ON(MAP_PAD_LEN_MASK < 3);
padding = ALIGN(map_datalen, 4) - map_datalen;
if (padding == 0)
goto done;
if (skb_tailroom(skb) < padding)
return NULL;
skb_put_zero(skb, padding);
done:
map_header->pkt_len = htons(map_datalen + padding);
/* This is a data packet, so the CMD bit is 0 */
map_header->flags = padding & MAP_PAD_LEN_MASK;
return map_header;
}
/* Deaggregates a single packet
* A whole new buffer is allocated for each portion of an aggregated frame.
* Caller should keep calling deaggregate() on the source skb until 0 is
* 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 rmnet_port *port)
{
struct rmnet_map_v5_csum_header *next_hdr = NULL;
struct rmnet_map_header *maph;
void *data = skb->data;
struct sk_buff *skbn;
u8 nexthdr_type;
u32 packet_len;
if (skb->len == 0)
return NULL;
maph = (struct rmnet_map_header *)skb->data;
packet_len = ntohs(maph->pkt_len) + sizeof(*maph);
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;
/* Some hardware can send us empty frames. Catch them */
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;
skb_reserve(skbn, RMNET_MAP_DEAGGR_HEADROOM);
skb_put(skbn, packet_len);
memcpy(skbn->data, skb->data, packet_len);
skb_pull(skb, packet_len);
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_priv *priv = netdev_priv(skb->dev);
struct rmnet_map_dl_csum_trailer *csum_trailer;
if (unlikely(!(skb->dev->features & NETIF_F_RXCSUM))) {
priv->stats.csum_sw++;
return -EOPNOTSUPP;
}
csum_trailer = (struct rmnet_map_dl_csum_trailer *)(skb->data + len);
if (!(csum_trailer->flags & MAP_CSUM_DL_VALID_FLAG)) {
priv->stats.csum_valid_unset++;
return -EINVAL;
}
if (skb->protocol == htons(ETH_P_IP))
return rmnet_map_ipv4_dl_csum_trailer(skb, csum_trailer, priv);
if (IS_ENABLED(CONFIG_IPV6) && skb->protocol == htons(ETH_P_IPV6))
return rmnet_map_ipv6_dl_csum_trailer(skb, csum_trailer, priv);
priv->stats.csum_err_invalid_ip_version++;
return -EPROTONOSUPPORT;
}
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;
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)
goto sw_csum;
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);
priv->stats.csum_hw++;
return;
}
if (IS_ENABLED(CONFIG_IPV6) && skb->protocol == htons(ETH_P_IPV6)) {
rmnet_map_ipv6_ul_csum_header(iphdr, ul_header, skb);
priv->stats.csum_hw++;
return;
}
priv->stats.csum_err_invalid_ip_version++;
sw_csum:
memset(ul_header, 0, sizeof(*ul_header));
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)
{
struct rmnet_priv *priv = netdev_priv(skb->dev);
struct rmnet_map_v5_csum_header *next_hdr;
u8 nexthdr_type;
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)
return -EINVAL;
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));
return 0;
}
#define RMNET_AGG_BYPASS_TIME_NSEC 10000000L
static void reset_aggr_params(struct rmnet_port *port)
{
port->skbagg_head = NULL;
port->agg_count = 0;
port->agg_state = 0;
memset(&port->agg_time, 0, sizeof(struct timespec64));
}
static void rmnet_send_skb(struct rmnet_port *port, struct sk_buff *skb)
{
if (skb_needs_linearize(skb, port->dev->features)) {
if (unlikely(__skb_linearize(skb))) {
struct rmnet_priv *priv;
priv = netdev_priv(port->rmnet_dev);
this_cpu_inc(priv->pcpu_stats->stats.tx_drops);
dev_kfree_skb_any(skb);
return;
}
}
dev_queue_xmit(skb);
}
static void rmnet_map_flush_tx_packet_work(struct work_struct *work)
{
struct sk_buff *skb = NULL;
struct rmnet_port *port;
port = container_of(work, struct rmnet_port, agg_wq);
spin_lock_bh(&port->agg_lock);
if (likely(port->agg_state == -EINPROGRESS)) {
/* Buffer may have already been shipped out */
if (likely(port->skbagg_head)) {
skb = port->skbagg_head;
reset_aggr_params(port);
}
port->agg_state = 0;
}
spin_unlock_bh(&port->agg_lock);
if (skb)
rmnet_send_skb(port, skb);
}
static enum hrtimer_restart rmnet_map_flush_tx_packet_queue(struct hrtimer *t)
{
struct rmnet_port *port;
port = container_of(t, struct rmnet_port, hrtimer);
schedule_work(&port->agg_wq);
return HRTIMER_NORESTART;
}
unsigned int rmnet_map_tx_aggregate(struct sk_buff *skb, struct rmnet_port *port,
struct net_device *orig_dev)
{
struct timespec64 diff, last;
unsigned int len = skb->len;
struct sk_buff *agg_skb;
int size;
spin_lock_bh(&port->agg_lock);
memcpy(&last, &port->agg_last, sizeof(struct timespec64));
ktime_get_real_ts64(&port->agg_last);
if (!port->skbagg_head) {
/* Check to see if we should agg first. If the traffic is very
* sparse, don't aggregate.
*/
new_packet:
diff = timespec64_sub(port->agg_last, last);
size = port->egress_agg_params.bytes - skb->len;
if (size < 0) {
/* dropped */
spin_unlock_bh(&port->agg_lock);
return 0;
}
if (diff.tv_sec > 0 || diff.tv_nsec > RMNET_AGG_BYPASS_TIME_NSEC ||
size == 0)
goto no_aggr;
port->skbagg_head = skb_copy_expand(skb, 0, size, GFP_ATOMIC);
if (!port->skbagg_head)
goto no_aggr;
dev_kfree_skb_any(skb);
port->skbagg_head->protocol = htons(ETH_P_MAP);
port->agg_count = 1;
ktime_get_real_ts64(&port->agg_time);
skb_frag_list_init(port->skbagg_head);
goto schedule;
}
diff = timespec64_sub(port->agg_last, port->agg_time);
size = port->egress_agg_params.bytes - port->skbagg_head->len;
if (skb->len > size) {
agg_skb = port->skbagg_head;
reset_aggr_params(port);
spin_unlock_bh(&port->agg_lock);
hrtimer_cancel(&port->hrtimer);
rmnet_send_skb(port, agg_skb);
spin_lock_bh(&port->agg_lock);
goto new_packet;
}
if (skb_has_frag_list(port->skbagg_head))
port->skbagg_tail->next = skb;
else
skb_shinfo(port->skbagg_head)->frag_list = skb;
port->skbagg_head->len += skb->len;
port->skbagg_head->data_len += skb->len;
port->skbagg_head->truesize += skb->truesize;
port->skbagg_tail = skb;
port->agg_count++;
if (diff.tv_sec > 0 || diff.tv_nsec > port->egress_agg_params.time_nsec ||
port->agg_count >= port->egress_agg_params.count ||
port->skbagg_head->len == port->egress_agg_params.bytes) {
agg_skb = port->skbagg_head;
reset_aggr_params(port);
spin_unlock_bh(&port->agg_lock);
hrtimer_cancel(&port->hrtimer);
rmnet_send_skb(port, agg_skb);
return len;
}
schedule:
if (!hrtimer_active(&port->hrtimer) && port->agg_state != -EINPROGRESS) {
port->agg_state = -EINPROGRESS;
hrtimer_start(&port->hrtimer,
ns_to_ktime(port->egress_agg_params.time_nsec),
HRTIMER_MODE_REL);
}
spin_unlock_bh(&port->agg_lock);
return len;
no_aggr:
spin_unlock_bh(&port->agg_lock);
skb->protocol = htons(ETH_P_MAP);
dev_queue_xmit(skb);
return len;
}
void rmnet_map_update_ul_agg_config(struct rmnet_port *port, u32 size,
u32 count, u32 time)
{
spin_lock_bh(&port->agg_lock);
port->egress_agg_params.bytes = size;
WRITE_ONCE(port->egress_agg_params.count, count);
port->egress_agg_params.time_nsec = time * NSEC_PER_USEC;
spin_unlock_bh(&port->agg_lock);
}
void rmnet_map_tx_aggregate_init(struct rmnet_port *port)
{
hrtimer_init(&port->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
port->hrtimer.function = rmnet_map_flush_tx_packet_queue;
spin_lock_init(&port->agg_lock);
rmnet_map_update_ul_agg_config(port, 4096, 1, 800);
INIT_WORK(&port->agg_wq, rmnet_map_flush_tx_packet_work);
}
void rmnet_map_tx_aggregate_exit(struct rmnet_port *port)
{
hrtimer_cancel(&port->hrtimer);
cancel_work_sync(&port->agg_wq);
spin_lock_bh(&port->agg_lock);
if (port->agg_state == -EINPROGRESS) {
if (port->skbagg_head) {
dev_kfree_skb_any(port->skbagg_head);
reset_aggr_params(port);
}
port->agg_state = 0;
}
spin_unlock_bh(&port->agg_lock);
}
Codebase Browser
linux