| /* |
| * CAIF Interface registration. |
| * Copyright (C) ST-Ericsson AB 2010 |
| * Author: Sjur Brendeland/sjur.brandeland@stericsson.com |
| * License terms: GNU General Public License (GPL) version 2 |
| * |
| * Borrowed heavily from file: pn_dev.c. Thanks to Remi Denis-Courmont |
| * and Sakari Ailus <sakari.ailus@nokia.com> |
| */ |
| |
| #define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__ |
| |
| #include <linux/kernel.h> |
| #include <linux/if_arp.h> |
| #include <linux/net.h> |
| #include <linux/netdevice.h> |
| #include <linux/mutex.h> |
| #include <linux/module.h> |
| #include <linux/spinlock.h> |
| #include <net/netns/generic.h> |
| #include <net/net_namespace.h> |
| #include <net/pkt_sched.h> |
| #include <net/caif/caif_device.h> |
| #include <net/caif/caif_layer.h> |
| #include <net/caif/cfpkt.h> |
| #include <net/caif/cfcnfg.h> |
| #include <net/caif/cfserl.h> |
| |
| MODULE_LICENSE("GPL"); |
| |
| /* Used for local tracking of the CAIF net devices */ |
| struct caif_device_entry { |
| struct cflayer layer; |
| struct list_head list; |
| struct net_device *netdev; |
| int __percpu *pcpu_refcnt; |
| spinlock_t flow_lock; |
| struct sk_buff *xoff_skb; |
| void (*xoff_skb_dtor)(struct sk_buff *skb); |
| bool xoff; |
| }; |
| |
| struct caif_device_entry_list { |
| struct list_head list; |
| /* Protects simulanous deletes in list */ |
| struct mutex lock; |
| }; |
| |
| struct caif_net { |
| struct cfcnfg *cfg; |
| struct caif_device_entry_list caifdevs; |
| }; |
| |
| static int caif_net_id; |
| static int q_high = 50; /* Percent */ |
| |
| struct cfcnfg *get_cfcnfg(struct net *net) |
| { |
| struct caif_net *caifn; |
| caifn = net_generic(net, caif_net_id); |
| return caifn->cfg; |
| } |
| EXPORT_SYMBOL(get_cfcnfg); |
| |
| static struct caif_device_entry_list *caif_device_list(struct net *net) |
| { |
| struct caif_net *caifn; |
| caifn = net_generic(net, caif_net_id); |
| return &caifn->caifdevs; |
| } |
| |
| static void caifd_put(struct caif_device_entry *e) |
| { |
| this_cpu_dec(*e->pcpu_refcnt); |
| } |
| |
| static void caifd_hold(struct caif_device_entry *e) |
| { |
| this_cpu_inc(*e->pcpu_refcnt); |
| } |
| |
| static int caifd_refcnt_read(struct caif_device_entry *e) |
| { |
| int i, refcnt = 0; |
| for_each_possible_cpu(i) |
| refcnt += *per_cpu_ptr(e->pcpu_refcnt, i); |
| return refcnt; |
| } |
| |
| /* Allocate new CAIF device. */ |
| static struct caif_device_entry *caif_device_alloc(struct net_device *dev) |
| { |
| struct caif_device_entry *caifd; |
| |
| caifd = kzalloc(sizeof(*caifd), GFP_KERNEL); |
| if (!caifd) |
| return NULL; |
| caifd->pcpu_refcnt = alloc_percpu(int); |
| if (!caifd->pcpu_refcnt) { |
| kfree(caifd); |
| return NULL; |
| } |
| caifd->netdev = dev; |
| dev_hold(dev); |
| return caifd; |
| } |
| |
| static struct caif_device_entry *caif_get(struct net_device *dev) |
| { |
| struct caif_device_entry_list *caifdevs = |
| caif_device_list(dev_net(dev)); |
| struct caif_device_entry *caifd; |
| |
| list_for_each_entry_rcu(caifd, &caifdevs->list, list) { |
| if (caifd->netdev == dev) |
| return caifd; |
| } |
| return NULL; |
| } |
| |
| void caif_flow_cb(struct sk_buff *skb) |
| { |
| struct caif_device_entry *caifd; |
| void (*dtor)(struct sk_buff *skb) = NULL; |
| bool send_xoff; |
| |
| WARN_ON(skb->dev == NULL); |
| |
| rcu_read_lock(); |
| caifd = caif_get(skb->dev); |
| caifd_hold(caifd); |
| rcu_read_unlock(); |
| |
| spin_lock_bh(&caifd->flow_lock); |
| send_xoff = caifd->xoff; |
| caifd->xoff = 0; |
| dtor = caifd->xoff_skb_dtor; |
| |
| if (WARN_ON(caifd->xoff_skb != skb)) |
| skb = NULL; |
| |
| caifd->xoff_skb = NULL; |
| caifd->xoff_skb_dtor = NULL; |
| |
| spin_unlock_bh(&caifd->flow_lock); |
| |
| if (dtor && skb) |
| dtor(skb); |
| |
| if (send_xoff) |
| caifd->layer.up-> |
| ctrlcmd(caifd->layer.up, |
| _CAIF_CTRLCMD_PHYIF_FLOW_ON_IND, |
| caifd->layer.id); |
| caifd_put(caifd); |
| } |
| |
| static int transmit(struct cflayer *layer, struct cfpkt *pkt) |
| { |
| int err, high = 0, qlen = 0; |
| struct caif_device_entry *caifd = |
| container_of(layer, struct caif_device_entry, layer); |
| struct sk_buff *skb; |
| struct netdev_queue *txq; |
| |
| rcu_read_lock_bh(); |
| |
| skb = cfpkt_tonative(pkt); |
| skb->dev = caifd->netdev; |
| skb_reset_network_header(skb); |
| skb->protocol = htons(ETH_P_CAIF); |
| |
| /* Check if we need to handle xoff */ |
| if (likely(caifd->netdev->tx_queue_len == 0)) |
| goto noxoff; |
| |
| if (unlikely(caifd->xoff)) |
| goto noxoff; |
| |
| if (likely(!netif_queue_stopped(caifd->netdev))) { |
| /* If we run with a TX queue, check if the queue is too long*/ |
| txq = netdev_get_tx_queue(skb->dev, 0); |
| qlen = qdisc_qlen(rcu_dereference_bh(txq->qdisc)); |
| |
| if (likely(qlen == 0)) |
| goto noxoff; |
| |
| high = (caifd->netdev->tx_queue_len * q_high) / 100; |
| if (likely(qlen < high)) |
| goto noxoff; |
| } |
| |
| /* Hold lock while accessing xoff */ |
| spin_lock_bh(&caifd->flow_lock); |
| if (caifd->xoff) { |
| spin_unlock_bh(&caifd->flow_lock); |
| goto noxoff; |
| } |
| |
| /* |
| * Handle flow off, we do this by temporary hi-jacking this |
| * skb's destructor function, and replace it with our own |
| * flow-on callback. The callback will set flow-on and call |
| * the original destructor. |
| */ |
| |
| pr_debug("queue has stopped(%d) or is full (%d > %d)\n", |
| netif_queue_stopped(caifd->netdev), |
| qlen, high); |
| caifd->xoff = 1; |
| caifd->xoff_skb = skb; |
| caifd->xoff_skb_dtor = skb->destructor; |
| skb->destructor = caif_flow_cb; |
| spin_unlock_bh(&caifd->flow_lock); |
| |
| caifd->layer.up->ctrlcmd(caifd->layer.up, |
| _CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND, |
| caifd->layer.id); |
| noxoff: |
| rcu_read_unlock_bh(); |
| |
| err = dev_queue_xmit(skb); |
| if (err > 0) |
| err = -EIO; |
| |
| return err; |
| } |
| |
| /* |
| * Stuff received packets into the CAIF stack. |
| * On error, returns non-zero and releases the skb. |
| */ |
| static int receive(struct sk_buff *skb, struct net_device *dev, |
| struct packet_type *pkttype, struct net_device *orig_dev) |
| { |
| struct cfpkt *pkt; |
| struct caif_device_entry *caifd; |
| int err; |
| |
| pkt = cfpkt_fromnative(CAIF_DIR_IN, skb); |
| |
| rcu_read_lock(); |
| caifd = caif_get(dev); |
| |
| if (!caifd || !caifd->layer.up || !caifd->layer.up->receive || |
| !netif_oper_up(caifd->netdev)) { |
| rcu_read_unlock(); |
| kfree_skb(skb); |
| return NET_RX_DROP; |
| } |
| |
| /* Hold reference to netdevice while using CAIF stack */ |
| caifd_hold(caifd); |
| rcu_read_unlock(); |
| |
| err = caifd->layer.up->receive(caifd->layer.up, pkt); |
| |
| /* For -EILSEQ the packet is not freed so so it now */ |
| if (err == -EILSEQ) |
| cfpkt_destroy(pkt); |
| |
| /* Release reference to stack upwards */ |
| caifd_put(caifd); |
| |
| if (err != 0) |
| err = NET_RX_DROP; |
| return err; |
| } |
| |
| static struct packet_type caif_packet_type __read_mostly = { |
| .type = cpu_to_be16(ETH_P_CAIF), |
| .func = receive, |
| }; |
| |
| static void dev_flowctrl(struct net_device *dev, int on) |
| { |
| struct caif_device_entry *caifd; |
| |
| rcu_read_lock(); |
| |
| caifd = caif_get(dev); |
| if (!caifd || !caifd->layer.up || !caifd->layer.up->ctrlcmd) { |
| rcu_read_unlock(); |
| return; |
| } |
| |
| caifd_hold(caifd); |
| rcu_read_unlock(); |
| |
| caifd->layer.up->ctrlcmd(caifd->layer.up, |
| on ? |
| _CAIF_CTRLCMD_PHYIF_FLOW_ON_IND : |
| _CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND, |
| caifd->layer.id); |
| caifd_put(caifd); |
| } |
| |
| void caif_enroll_dev(struct net_device *dev, struct caif_dev_common *caifdev, |
| struct cflayer *link_support, int head_room, |
| struct cflayer **layer, int (**rcv_func)( |
| struct sk_buff *, struct net_device *, |
| struct packet_type *, struct net_device *)) |
| { |
| struct caif_device_entry *caifd; |
| enum cfcnfg_phy_preference pref; |
| struct cfcnfg *cfg = get_cfcnfg(dev_net(dev)); |
| struct caif_device_entry_list *caifdevs; |
| |
| caifdevs = caif_device_list(dev_net(dev)); |
| caifd = caif_device_alloc(dev); |
| if (!caifd) |
| return; |
| *layer = &caifd->layer; |
| spin_lock_init(&caifd->flow_lock); |
| |
| switch (caifdev->link_select) { |
| case CAIF_LINK_HIGH_BANDW: |
| pref = CFPHYPREF_HIGH_BW; |
| break; |
| case CAIF_LINK_LOW_LATENCY: |
| pref = CFPHYPREF_LOW_LAT; |
| break; |
| default: |
| pref = CFPHYPREF_HIGH_BW; |
| break; |
| } |
| mutex_lock(&caifdevs->lock); |
| list_add_rcu(&caifd->list, &caifdevs->list); |
| |
| strncpy(caifd->layer.name, dev->name, |
| sizeof(caifd->layer.name) - 1); |
| caifd->layer.name[sizeof(caifd->layer.name) - 1] = 0; |
| caifd->layer.transmit = transmit; |
| cfcnfg_add_phy_layer(cfg, |
| dev, |
| &caifd->layer, |
| pref, |
| link_support, |
| caifdev->use_fcs, |
| head_room); |
| mutex_unlock(&caifdevs->lock); |
| if (rcv_func) |
| *rcv_func = receive; |
| } |
| EXPORT_SYMBOL(caif_enroll_dev); |
| |
| /* notify Caif of device events */ |
| static int caif_device_notify(struct notifier_block *me, unsigned long what, |
| void *arg) |
| { |
| struct net_device *dev = arg; |
| struct caif_device_entry *caifd = NULL; |
| struct caif_dev_common *caifdev; |
| struct cfcnfg *cfg; |
| struct cflayer *layer, *link_support; |
| int head_room = 0; |
| struct caif_device_entry_list *caifdevs; |
| |
| cfg = get_cfcnfg(dev_net(dev)); |
| caifdevs = caif_device_list(dev_net(dev)); |
| |
| caifd = caif_get(dev); |
| if (caifd == NULL && dev->type != ARPHRD_CAIF) |
| return 0; |
| |
| switch (what) { |
| case NETDEV_REGISTER: |
| if (caifd != NULL) |
| break; |
| |
| caifdev = netdev_priv(dev); |
| |
| link_support = NULL; |
| if (caifdev->use_frag) { |
| head_room = 1; |
| link_support = cfserl_create(dev->ifindex, |
| caifdev->use_stx); |
| if (!link_support) { |
| pr_warn("Out of memory\n"); |
| break; |
| } |
| } |
| caif_enroll_dev(dev, caifdev, link_support, head_room, |
| &layer, NULL); |
| caifdev->flowctrl = dev_flowctrl; |
| break; |
| |
| case NETDEV_UP: |
| rcu_read_lock(); |
| |
| caifd = caif_get(dev); |
| if (caifd == NULL) { |
| rcu_read_unlock(); |
| break; |
| } |
| |
| caifd->xoff = 0; |
| cfcnfg_set_phy_state(cfg, &caifd->layer, true); |
| rcu_read_unlock(); |
| |
| break; |
| |
| case NETDEV_DOWN: |
| rcu_read_lock(); |
| |
| caifd = caif_get(dev); |
| if (!caifd || !caifd->layer.up || !caifd->layer.up->ctrlcmd) { |
| rcu_read_unlock(); |
| return -EINVAL; |
| } |
| |
| cfcnfg_set_phy_state(cfg, &caifd->layer, false); |
| caifd_hold(caifd); |
| rcu_read_unlock(); |
| |
| caifd->layer.up->ctrlcmd(caifd->layer.up, |
| _CAIF_CTRLCMD_PHYIF_DOWN_IND, |
| caifd->layer.id); |
| |
| spin_lock_bh(&caifd->flow_lock); |
| |
| /* |
| * Replace our xoff-destructor with original destructor. |
| * We trust that skb->destructor *always* is called before |
| * the skb reference is invalid. The hijacked SKB destructor |
| * takes the flow_lock so manipulating the skb->destructor here |
| * should be safe. |
| */ |
| if (caifd->xoff_skb_dtor != NULL && caifd->xoff_skb != NULL) |
| caifd->xoff_skb->destructor = caifd->xoff_skb_dtor; |
| |
| caifd->xoff = 0; |
| caifd->xoff_skb_dtor = NULL; |
| caifd->xoff_skb = NULL; |
| |
| spin_unlock_bh(&caifd->flow_lock); |
| caifd_put(caifd); |
| break; |
| |
| case NETDEV_UNREGISTER: |
| mutex_lock(&caifdevs->lock); |
| |
| caifd = caif_get(dev); |
| if (caifd == NULL) { |
| mutex_unlock(&caifdevs->lock); |
| break; |
| } |
| list_del_rcu(&caifd->list); |
| |
| /* |
| * NETDEV_UNREGISTER is called repeatedly until all reference |
| * counts for the net-device are released. If references to |
| * caifd is taken, simply ignore NETDEV_UNREGISTER and wait for |
| * the next call to NETDEV_UNREGISTER. |
| * |
| * If any packets are in flight down the CAIF Stack, |
| * cfcnfg_del_phy_layer will return nonzero. |
| * If no packets are in flight, the CAIF Stack associated |
| * with the net-device un-registering is freed. |
| */ |
| |
| if (caifd_refcnt_read(caifd) != 0 || |
| cfcnfg_del_phy_layer(cfg, &caifd->layer) != 0) { |
| |
| pr_info("Wait for device inuse\n"); |
| /* Enrole device if CAIF Stack is still in use */ |
| list_add_rcu(&caifd->list, &caifdevs->list); |
| mutex_unlock(&caifdevs->lock); |
| break; |
| } |
| |
| synchronize_rcu(); |
| dev_put(caifd->netdev); |
| free_percpu(caifd->pcpu_refcnt); |
| kfree(caifd); |
| |
| mutex_unlock(&caifdevs->lock); |
| break; |
| } |
| return 0; |
| } |
| |
| static struct notifier_block caif_device_notifier = { |
| .notifier_call = caif_device_notify, |
| .priority = 0, |
| }; |
| |
| /* Per-namespace Caif devices handling */ |
| static int caif_init_net(struct net *net) |
| { |
| struct caif_net *caifn = net_generic(net, caif_net_id); |
| INIT_LIST_HEAD(&caifn->caifdevs.list); |
| mutex_init(&caifn->caifdevs.lock); |
| |
| caifn->cfg = cfcnfg_create(); |
| if (!caifn->cfg) |
| return -ENOMEM; |
| |
| return 0; |
| } |
| |
| static void caif_exit_net(struct net *net) |
| { |
| struct caif_device_entry *caifd, *tmp; |
| struct caif_device_entry_list *caifdevs = |
| caif_device_list(net); |
| struct cfcnfg *cfg = get_cfcnfg(net); |
| |
| rtnl_lock(); |
| mutex_lock(&caifdevs->lock); |
| |
| list_for_each_entry_safe(caifd, tmp, &caifdevs->list, list) { |
| int i = 0; |
| list_del_rcu(&caifd->list); |
| cfcnfg_set_phy_state(cfg, &caifd->layer, false); |
| |
| while (i < 10 && |
| (caifd_refcnt_read(caifd) != 0 || |
| cfcnfg_del_phy_layer(cfg, &caifd->layer) != 0)) { |
| |
| pr_info("Wait for device inuse\n"); |
| msleep(250); |
| i++; |
| } |
| synchronize_rcu(); |
| dev_put(caifd->netdev); |
| free_percpu(caifd->pcpu_refcnt); |
| kfree(caifd); |
| } |
| cfcnfg_remove(cfg); |
| |
| mutex_unlock(&caifdevs->lock); |
| rtnl_unlock(); |
| } |
| |
| static struct pernet_operations caif_net_ops = { |
| .init = caif_init_net, |
| .exit = caif_exit_net, |
| .id = &caif_net_id, |
| .size = sizeof(struct caif_net), |
| }; |
| |
| /* Initialize Caif devices list */ |
| static int __init caif_device_init(void) |
| { |
| int result; |
| |
| result = register_pernet_subsys(&caif_net_ops); |
| |
| if (result) |
| return result; |
| |
| register_netdevice_notifier(&caif_device_notifier); |
| dev_add_pack(&caif_packet_type); |
| |
| return result; |
| } |
| |
| static void __exit caif_device_exit(void) |
| { |
| unregister_pernet_subsys(&caif_net_ops); |
| unregister_netdevice_notifier(&caif_device_notifier); |
| dev_remove_pack(&caif_packet_type); |
| } |
| |
| module_init(caif_device_init); |
| module_exit(caif_device_exit); |