mac802154: Handle association requests from peers

Coordinators may have to handle association requests from peers which
want to join the PAN. The logic involves:
- Acknowledging the request (done by hardware)
- If requested, a random short address that is free on this PAN should
  be chosen for the device.
- Sending an association response with the short address allocated for
  the peer and expecting it to be ack'ed.

If anything fails during this procedure, the peer is considered not
associated.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Stefan Schmidt <stefan@datenfreihafen.org>
Acked-by: Alexander Aring <aahringo@redhat.com>
Link: https://lore.kernel.org/linux-wpan/20230927181214.129346-8-miquel.raynal@bootlin.com

diff --git a/include/net/cfg802154.h b/include/net/cfg802154.h
index 9b036ab20079add6daa6db90dd4847961de6e877..c844ae63bc0407eeef3602806f5a15bbccac4c76 100644 (file)
--- a/include/net/cfg802154.h
+++ b/include/net/cfg802154.h
@@ -583,4 +583,11 @@ struct ieee802154_pan_device *
 cfg802154_device_is_child(struct wpan_dev *wpan_dev,
                          struct ieee802154_addr *target);
 
+/**
+ * cfg802154_get_free_short_addr - Get a free address among the known devices
+ * @wpan_dev: the wpan device
+ * @return: a random short address expectedly unused on our PAN
+ */
+__le16 cfg802154_get_free_short_addr(struct wpan_dev *wpan_dev);
+
 #endif /* __NET_CFG802154_H */

diff --git a/include/net/ieee802154_netdev.h b/include/net/ieee802154_netdev.h
index 16194356cfe76f98e5e80da2fa50093f51bafa1b..4de858f9929e3d48833bf0582d73e60ebb5dc23f 100644 (file)
--- a/include/net/ieee802154_netdev.h
+++ b/include/net/ieee802154_netdev.h
@@ -211,6 +211,12 @@ struct ieee802154_association_req_frame {
        struct ieee802154_assoc_req_pl assoc_req_pl;
 };
 
+struct ieee802154_association_resp_frame {
+       struct ieee802154_hdr mhr;
+       struct ieee802154_mac_cmd_pl mac_pl;
+       struct ieee802154_assoc_resp_pl assoc_resp_pl;
+};
+
 struct ieee802154_disassociation_notif_frame {
        struct ieee802154_hdr mhr;
        struct ieee802154_mac_cmd_pl mac_pl;

diff --git a/net/ieee802154/core.c b/net/ieee802154/core.c
index a08d75dd56ad641ac7f8ee7e54ddd0ee12f21c1a..1670a71327a7c5baaa45c89d7ecb77773a50743b 100644 (file)
--- a/net/ieee802154/core.c
+++ b/net/ieee802154/core.c
@@ -200,11 +200,18 @@ EXPORT_SYMBOL(wpan_phy_free);
 
 static void cfg802154_free_peer_structures(struct wpan_dev *wpan_dev)
 {
+       struct ieee802154_pan_device *child, *tmp;
+
        mutex_lock(&wpan_dev->association_lock);
 
        kfree(wpan_dev->parent);
        wpan_dev->parent = NULL;
 
+       list_for_each_entry_safe(child, tmp, &wpan_dev->children, node) {
+               list_del(&child->node);
+               kfree(child);
+       }
+
        mutex_unlock(&wpan_dev->association_lock);
 }
 

diff --git a/net/ieee802154/pan.c b/net/ieee802154/pan.c
index 43b8d2df2186a8fdbb63b7c7bfa5fe29128902e2..545461069197d0bdcf461fb83663b6368432c43b 100644 (file)
--- a/net/ieee802154/pan.c
+++ b/net/ieee802154/pan.c
@@ -63,3 +63,33 @@ cfg802154_device_is_child(struct wpan_dev *wpan_dev,
        return NULL;
 }
 EXPORT_SYMBOL_GPL(cfg802154_device_is_child);
+
+__le16 cfg802154_get_free_short_addr(struct wpan_dev *wpan_dev)
+{
+       struct ieee802154_pan_device *child;
+       __le16 addr;
+
+       lockdep_assert_held(&wpan_dev->association_lock);
+
+       do {
+               get_random_bytes(&addr, 2);
+               if (addr == cpu_to_le16(IEEE802154_ADDR_SHORT_BROADCAST) ||
+                   addr == cpu_to_le16(IEEE802154_ADDR_SHORT_UNSPEC))
+                       continue;
+
+               if (wpan_dev->short_addr == addr)
+                       continue;
+
+               if (wpan_dev->parent && wpan_dev->parent->short_addr == addr)
+                       continue;
+
+               list_for_each_entry(child, &wpan_dev->children, node)
+                       if (child->short_addr == addr)
+                               continue;
+
+               break;
+       } while (1);
+
+       return addr;
+}
+EXPORT_SYMBOL_GPL(cfg802154_get_free_short_addr);

diff --git a/net/mac802154/ieee802154_i.h b/net/mac802154/ieee802154_i.h
index 92252f86c69c087faa1d775c3cf0ed2b24d8c077..432bfa87249ee95abd90f990d2c90b367240c7c3 100644 (file)
--- a/net/mac802154/ieee802154_i.h
+++ b/net/mac802154/ieee802154_i.h
@@ -318,6 +318,8 @@ static inline bool mac802154_is_associating(struct ieee802154_local *local)
 int mac802154_send_disassociation_notif(struct ieee802154_sub_if_data *sdata,
                                        struct ieee802154_pan_device *target,
                                        u8 reason);
+int mac802154_process_association_req(struct ieee802154_sub_if_data *sdata,
+                                     struct sk_buff *skb);
 
 /* interface handling */
 int ieee802154_iface_init(void);

diff --git a/net/mac802154/rx.c b/net/mac802154/rx.c
index d0e08613a36bffcd972f83d5738cd1735db77889..96040b63a4fc55e014d2882dc5893bb2e9a8b736 100644 (file)
--- a/net/mac802154/rx.c
+++ b/net/mac802154/rx.c
@@ -102,6 +102,14 @@ void mac802154_rx_mac_cmd_worker(struct work_struct *work)
                mac802154_process_association_resp(mac_pkt->sdata, mac_pkt->skb);
                break;
 
+       case IEEE802154_CMD_ASSOCIATION_REQ:
+               dev_dbg(&mac_pkt->sdata->dev->dev, "processing ASSOC REQ\n");
+               if (mac_pkt->sdata->wpan_dev.iftype != NL802154_IFTYPE_COORD)
+                       break;
+
+               mac802154_process_association_req(mac_pkt->sdata, mac_pkt->skb);
+               break;
+
        default:
                break;
        }

diff --git a/net/mac802154/scan.c b/net/mac802154/scan.c
index e2f2e1235ec6e533161a0f662d63d5301af30174..d5f66c204bc5ed2277eaaca7922fe1e40d337d93 100644 (file)
--- a/net/mac802154/scan.c
+++ b/net/mac802154/scan.c
@@ -697,3 +697,145 @@ int mac802154_send_disassociation_notif(struct ieee802154_sub_if_data *sdata,
        dev_dbg(&sdata->dev->dev, "DISASSOC ACK received from %8phC\n", &teaddr);
        return 0;
 }
+
+static int
+mac802154_send_association_resp_locked(struct ieee802154_sub_if_data *sdata,
+                                      struct ieee802154_pan_device *target,
+                                      struct ieee802154_assoc_resp_pl *assoc_resp_pl)
+{
+       u64 teaddr = swab64((__force u64)target->extended_addr);
+       struct ieee802154_association_resp_frame frame = {};
+       struct ieee802154_local *local = sdata->local;
+       struct wpan_dev *wpan_dev = &sdata->wpan_dev;
+       struct sk_buff *skb;
+       int ret;
+
+       frame.mhr.fc.type = IEEE802154_FC_TYPE_MAC_CMD;
+       frame.mhr.fc.security_enabled = 0;
+       frame.mhr.fc.frame_pending = 0;
+       frame.mhr.fc.ack_request = 1; /* We always expect an ack here */
+       frame.mhr.fc.intra_pan = 1;
+       frame.mhr.fc.dest_addr_mode = IEEE802154_EXTENDED_ADDRESSING;
+       frame.mhr.fc.version = IEEE802154_2003_STD;
+       frame.mhr.fc.source_addr_mode = IEEE802154_EXTENDED_ADDRESSING;
+       frame.mhr.source.mode = IEEE802154_ADDR_LONG;
+       frame.mhr.source.extended_addr = wpan_dev->extended_addr;
+       frame.mhr.dest.mode = IEEE802154_ADDR_LONG;
+       frame.mhr.dest.pan_id = wpan_dev->pan_id;
+       frame.mhr.dest.extended_addr = target->extended_addr;
+       frame.mhr.seq = atomic_inc_return(&wpan_dev->dsn) & 0xFF;
+       frame.mac_pl.cmd_id = IEEE802154_CMD_ASSOCIATION_RESP;
+
+       skb = alloc_skb(IEEE802154_MAC_CMD_SKB_SZ + sizeof(*assoc_resp_pl),
+                       GFP_KERNEL);
+       if (!skb)
+               return -ENOBUFS;
+
+       skb->dev = sdata->dev;
+
+       ret = ieee802154_mac_cmd_push(skb, &frame, assoc_resp_pl,
+                                     sizeof(*assoc_resp_pl));
+       if (ret) {
+               kfree_skb(skb);
+               return ret;
+       }
+
+       ret = ieee802154_mlme_tx_locked(local, sdata, skb);
+       if (ret) {
+               dev_warn(&sdata->dev->dev,
+                        "No ASSOC RESP ACK received from %8phC\n", &teaddr);
+               if (ret > 0)
+                       ret = (ret == IEEE802154_NO_ACK) ? -EREMOTEIO : -EIO;
+               return ret;
+       }
+
+       return 0;
+}
+
+int mac802154_process_association_req(struct ieee802154_sub_if_data *sdata,
+                                     struct sk_buff *skb)
+{
+       struct wpan_dev *wpan_dev = &sdata->wpan_dev;
+       struct ieee802154_addr *src = &mac_cb(skb)->source;
+       struct ieee802154_addr *dest = &mac_cb(skb)->dest;
+       struct ieee802154_assoc_resp_pl assoc_resp_pl = {};
+       struct ieee802154_assoc_req_pl assoc_req_pl;
+       struct ieee802154_pan_device *child, *exchild;
+       struct ieee802154_addr tmp = {};
+       u64 ceaddr;
+       int ret;
+
+       if (skb->len != sizeof(assoc_req_pl))
+               return -EINVAL;
+
+       if (unlikely(src->mode != IEEE802154_EXTENDED_ADDRESSING))
+               return -EINVAL;
+
+       if (unlikely(dest->pan_id != wpan_dev->pan_id))
+               return -ENODEV;
+
+       if (dest->mode == IEEE802154_EXTENDED_ADDRESSING &&
+           unlikely(dest->extended_addr != wpan_dev->extended_addr))
+               return -ENODEV;
+       else if (dest->mode == IEEE802154_SHORT_ADDRESSING &&
+                unlikely(dest->short_addr != wpan_dev->short_addr))
+               return -ENODEV;
+
+       mutex_lock(&wpan_dev->association_lock);
+
+       memcpy(&assoc_req_pl, skb->data, sizeof(assoc_req_pl));
+       if (assoc_req_pl.assoc_type) {
+               dev_err(&skb->dev->dev, "Fast associations not supported yet\n");
+               ret = -EOPNOTSUPP;
+               goto unlock;
+       }
+
+       child = kzalloc(sizeof(*child), GFP_KERNEL);
+       if (!child) {
+               ret = -ENOMEM;
+               goto unlock;
+       }
+
+       child->extended_addr = src->extended_addr;
+       child->mode = IEEE802154_EXTENDED_ADDRESSING;
+       ceaddr = swab64((__force u64)child->extended_addr);
+
+       assoc_resp_pl.status = IEEE802154_ASSOCIATION_SUCCESSFUL;
+       if (assoc_req_pl.alloc_addr) {
+               assoc_resp_pl.short_addr = cfg802154_get_free_short_addr(wpan_dev);
+               child->mode = IEEE802154_SHORT_ADDRESSING;
+       } else {
+               assoc_resp_pl.short_addr = cpu_to_le16(IEEE802154_ADDR_SHORT_UNSPEC);
+       }
+       child->short_addr = assoc_resp_pl.short_addr;
+       dev_dbg(&sdata->dev->dev,
+               "Accepting ASSOC REQ from child %8phC, providing short address 0x%04x\n",
+               &ceaddr, le16_to_cpu(child->short_addr));
+
+       ret = mac802154_send_association_resp_locked(sdata, child, &assoc_resp_pl);
+       if (ret) {
+               kfree(child);
+               goto unlock;
+       }
+
+       dev_dbg(&sdata->dev->dev,
+               "Successful association with new child %8phC\n", &ceaddr);
+
+       /* Ensure this child is not already associated (might happen due to
+        * retransmissions), in this case drop the ex structure.
+        */
+       tmp.mode = child->mode;
+       tmp.extended_addr = child->extended_addr;
+       exchild = cfg802154_device_is_child(wpan_dev, &tmp);
+       if (exchild) {
+               dev_dbg(&sdata->dev->dev,
+                       "Child %8phC was already known\n", &ceaddr);
+               list_del(&exchild->node);
+       }
+
+       list_add(&child->node, &wpan_dev->children);
+
+unlock:
+       mutex_unlock(&wpan_dev->association_lock);
+       return ret;
+}