net/dsa/tag.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * DSA tagging protocol handling
   4  *
   5  * Copyright (c) 2008-2009 Marvell Semiconductor
   6  * Copyright (c) 2013 Florian Fainelli <florian@openwrt.org>
   7  * Copyright (c) 2016 Andrew Lunn <andrew@lunn.ch>
   8  */
   9
  10 #include <linux/netdevice.h>
  11 #include <linux/ptp_classify.h>
  12 #include <linux/skbuff.h>
  13 #include <net/dsa.h>
  14 #include <net/dst_metadata.h>
  15
  16 #include "slave.h"
  17 #include "tag.h"
  18
  19 static LIST_HEAD(dsa_tag_drivers_list);
  20 static DEFINE_MUTEX(dsa_tag_drivers_lock);
  21
  22 /* Determine if we should defer delivery of skb until we have a rx timestamp.
  23  *
  24  * Called from dsa_switch_rcv. For now, this will only work if tagging is
  25  * enabled on the switch. Normally the MAC driver would retrieve the hardware
  26  * timestamp when it reads the packet out of the hardware. However in a DSA
  27  * switch, the DSA driver owning the interface to which the packet is
  28  * delivered is never notified unless we do so here.
  29  */
  30 static bool dsa_skb_defer_rx_timestamp(struct dsa_slave_priv *p,
  31                                        struct sk_buff *skb)
  32 {
  33         struct dsa_switch *ds = p->dp->ds;
  34         unsigned int type;
  35
  36         if (!ds->ops->port_rxtstamp)
  37                 return false;
  38
  39         if (skb_headroom(skb) < ETH_HLEN)
  40                 return false;
  41
  42         __skb_push(skb, ETH_HLEN);
  43
  44         type = ptp_classify_raw(skb);
  45
  46         __skb_pull(skb, ETH_HLEN);
  47
  48         if (type == PTP_CLASS_NONE)
  49                 return false;
  50
  51         return ds->ops->port_rxtstamp(ds, p->dp->index, skb, type);
  52 }
  53
  54 static int dsa_switch_rcv(struct sk_buff *skb, struct net_device *dev,
  55                           struct packet_type *pt, struct net_device *unused)
  56 {
  57         struct metadata_dst *md_dst = skb_metadata_dst(skb);
  58         struct dsa_port *cpu_dp = dev->dsa_ptr;
  59         struct sk_buff *nskb = NULL;
  60         struct dsa_slave_priv *p;
  61
  62         if (unlikely(!cpu_dp)) {
  63                 kfree_skb(skb);
  64                 return 0;
  65         }
  66
  67         skb = skb_unshare(skb, GFP_ATOMIC);
  68         if (!skb)
  69                 return 0;
  70
  71         if (md_dst && md_dst->type == METADATA_HW_PORT_MUX) {
  72                 unsigned int port = md_dst->u.port_info.port_id;
  73
  74                 skb_dst_drop(skb);
  75                 if (!skb_has_extensions(skb))
  76                         skb->slow_gro = 0;
  77
  78                 skb->dev = dsa_master_find_slave(dev, 0, port);
  79                 if (likely(skb->dev)) {
  80                         dsa_default_offload_fwd_mark(skb);
  81                         nskb = skb;
  82                 }
  83         } else {
  84                 nskb = cpu_dp->rcv(skb, dev);
  85         }
  86
  87         if (!nskb) {
  88                 kfree_skb(skb);
  89                 return 0;
  90         }
  91
  92         skb = nskb;
  93         skb_push(skb, ETH_HLEN);
  94         skb->pkt_type = PACKET_HOST;
  95         skb->protocol = eth_type_trans(skb, skb->dev);
  96
  97         if (unlikely(!dsa_slave_dev_check(skb->dev))) {
  98                 /* Packet is to be injected directly on an upper
  99                  * device, e.g. a team/bond, so skip all DSA-port
 100                  * specific actions.
 101                  */
 102                 netif_rx(skb);
 103                 return 0;
 104         }
 105
 106         p = netdev_priv(skb->dev);
 107
 108         if (unlikely(cpu_dp->ds->untag_bridge_pvid)) {
 109                 nskb = dsa_untag_bridge_pvid(skb);
 110                 if (!nskb) {
 111                         kfree_skb(skb);
 112                         return 0;
 113                 }
 114                 skb = nskb;
 115         }
 116
 117         dev_sw_netstats_rx_add(skb->dev, skb->len + ETH_HLEN);
 118
 119         if (dsa_skb_defer_rx_timestamp(p, skb))
 120                 return 0;
 121
 122         gro_cells_receive(&p->gcells, skb);
 123
 124         return 0;
 125 }
 126
 127 struct packet_type dsa_pack_type __read_mostly = {
 128         .type   = cpu_to_be16(ETH_P_XDSA),
 129         .func   = dsa_switch_rcv,
 130 };
 131
 132 static void dsa_tag_driver_register(struct dsa_tag_driver *dsa_tag_driver,
 133                                     struct module *owner)
 134 {
 135         dsa_tag_driver->owner = owner;
 136
 137         mutex_lock(&dsa_tag_drivers_lock);
 138         list_add_tail(&dsa_tag_driver->list, &dsa_tag_drivers_list);
 139         mutex_unlock(&dsa_tag_drivers_lock);
 140 }
 141
 142 void dsa_tag_drivers_register(struct dsa_tag_driver *dsa_tag_driver_array[],
 143                               unsigned int count, struct module *owner)
 144 {
 145         unsigned int i;
 146
 147         for (i = 0; i < count; i++)
 148                 dsa_tag_driver_register(dsa_tag_driver_array[i], owner);
 149 }
 150
 151 static void dsa_tag_driver_unregister(struct dsa_tag_driver *dsa_tag_driver)
 152 {
 153         mutex_lock(&dsa_tag_drivers_lock);
 154         list_del(&dsa_tag_driver->list);
 155         mutex_unlock(&dsa_tag_drivers_lock);
 156 }
 157 EXPORT_SYMBOL_GPL(dsa_tag_drivers_register);
 158
 159 void dsa_tag_drivers_unregister(struct dsa_tag_driver *dsa_tag_driver_array[],
 160                                 unsigned int count)
 161 {
 162         unsigned int i;
 163
 164         for (i = 0; i < count; i++)
 165                 dsa_tag_driver_unregister(dsa_tag_driver_array[i]);
 166 }
 167 EXPORT_SYMBOL_GPL(dsa_tag_drivers_unregister);
 168
 169 const char *dsa_tag_protocol_to_str(const struct dsa_device_ops *ops)
 170 {
 171         return ops->name;
 172 };
 173
 174 /* Function takes a reference on the module owning the tagger,
 175  * so dsa_tag_driver_put must be called afterwards.
 176  */
 177 const struct dsa_device_ops *dsa_tag_driver_get_by_name(const char *name)
 178 {
 179         const struct dsa_device_ops *ops = ERR_PTR(-ENOPROTOOPT);
 180         struct dsa_tag_driver *dsa_tag_driver;
 181
 182         request_module("%s%s", DSA_TAG_DRIVER_ALIAS, name);
 183
 184         mutex_lock(&dsa_tag_drivers_lock);
 185         list_for_each_entry(dsa_tag_driver, &dsa_tag_drivers_list, list) {
 186                 const struct dsa_device_ops *tmp = dsa_tag_driver->ops;
 187
 188                 if (strcmp(name, tmp->name))
 189                         continue;
 190
 191                 if (!try_module_get(dsa_tag_driver->owner))
 192                         break;
 193
 194                 ops = tmp;
 195                 break;
 196         }
 197         mutex_unlock(&dsa_tag_drivers_lock);
 198
 199         return ops;
 200 }
 201
 202 const struct dsa_device_ops *dsa_tag_driver_get_by_id(int tag_protocol)
 203 {
 204         struct dsa_tag_driver *dsa_tag_driver;
 205         const struct dsa_device_ops *ops;
 206         bool found = false;
 207
 208         request_module("%sid-%d", DSA_TAG_DRIVER_ALIAS, tag_protocol);
 209
 210         mutex_lock(&dsa_tag_drivers_lock);
 211         list_for_each_entry(dsa_tag_driver, &dsa_tag_drivers_list, list) {
 212                 ops = dsa_tag_driver->ops;
 213                 if (ops->proto == tag_protocol) {
 214                         found = true;
 215                         break;
 216                 }
 217         }
 218
 219         if (found) {
 220                 if (!try_module_get(dsa_tag_driver->owner))
 221                         ops = ERR_PTR(-ENOPROTOOPT);
 222         } else {
 223                 ops = ERR_PTR(-ENOPROTOOPT);
 224         }
 225
 226         mutex_unlock(&dsa_tag_drivers_lock);
 227
 228         return ops;
 229 }
 230
 231 void dsa_tag_driver_put(const struct dsa_device_ops *ops)
 232 {
 233         struct dsa_tag_driver *dsa_tag_driver;
 234
 235         mutex_lock(&dsa_tag_drivers_lock);
 236         list_for_each_entry(dsa_tag_driver, &dsa_tag_drivers_list, list) {
 237                 if (dsa_tag_driver->ops == ops) {
 238                         module_put(dsa_tag_driver->owner);
 239                         break;
 240                 }
 241         }
 242         mutex_unlock(&dsa_tag_drivers_lock);
 243 }