ieee802154: Advertize coordinators discovery

Let's introduce the basics for advertizing discovered PANs and
coordinators, which is:
- A new "scan" netlink message group.
- A couple of netlink command/attribute.
- The main netlink helper to send a netlink message with all the
  necessary information to forward the main information to the user.

Two netlink attributes are proactively added to support future UWB
complex channels, but are not actually used yet.

Co-developed-by: David Girault <david.girault@qorvo.com>
Signed-off-by: David Girault <david.girault@qorvo.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Alexander Aring <aahringo@redhat.com>
Link: https://lore.kernel.org/r/20221129135535.532513-2-miquel.raynal@bootlin.com
Signed-off-by: Stefan Schmidt <stefan@datenfreihafen.org>

2 files changed, 105 insertions, 0 deletions

diff --git a/net/ieee802154/nl802154.c b/net/ieee802154/nl802154.c
index 38c4f3cb010e..80dc73182785 100644
--- a/net/ieee802154/nl802154.c
+++ b/net/ieee802154/nl802154.c
@@ -26,10 +26,12 @@ static struct genl_family nl802154_fam;
 /* multicast groups */
 enum nl802154_multicast_groups {
 	NL802154_MCGRP_CONFIG,
+	NL802154_MCGRP_SCAN,
 };
 
 static const struct genl_multicast_group nl802154_mcgrps[] = {
 	[NL802154_MCGRP_CONFIG] = { .name = "config", },
+	[NL802154_MCGRP_SCAN] = { .name = "scan", },
 };
 
 /* returns ERR_PTR values */
@@ -216,6 +218,9 @@ static const struct nla_policy nl802154_policy[NL802154_ATTR_MAX+1] = {
 
 	[NL802154_ATTR_PID] = { .type = NLA_U32 },
 	[NL802154_ATTR_NETNS_FD] = { .type = NLA_U32 },
+
+	[NL802154_ATTR_COORDINATOR] = { .type = NLA_NESTED },
+
 #ifdef CONFIG_IEEE802154_NL802154_EXPERIMENTAL
 	[NL802154_ATTR_SEC_ENABLED] = { .type = NLA_U8, },
 	[NL802154_ATTR_SEC_OUT_LEVEL] = { .type = NLA_U32, },
@@ -1281,6 +1286,104 @@ static int nl802154_wpan_phy_netns(struct sk_buff *skb, struct genl_info *info)
 	return err;
 }
 
+static int nl802154_prep_scan_event_msg(struct sk_buff *msg,
+					struct cfg802154_registered_device *rdev,
+					struct wpan_dev *wpan_dev,
+					u32 portid, u32 seq, int flags, u8 cmd,
+					struct ieee802154_coord_desc *desc)
+{
+	struct nlattr *nla;
+	void *hdr;
+
+	hdr = nl802154hdr_put(msg, portid, seq, flags, cmd);
+	if (!hdr)
+		return -ENOBUFS;
+
+	if (nla_put_u32(msg, NL802154_ATTR_WPAN_PHY, rdev->wpan_phy_idx))
+		goto nla_put_failure;
+
+	if (wpan_dev->netdev &&
+	    nla_put_u32(msg, NL802154_ATTR_IFINDEX, wpan_dev->netdev->ifindex))
+		goto nla_put_failure;
+
+	if (nla_put_u64_64bit(msg, NL802154_ATTR_WPAN_DEV,
+			      wpan_dev_id(wpan_dev), NL802154_ATTR_PAD))
+		goto nla_put_failure;
+
+	nla = nla_nest_start_noflag(msg, NL802154_ATTR_COORDINATOR);
+	if (!nla)
+		goto nla_put_failure;
+
+	if (nla_put(msg, NL802154_COORD_PANID, IEEE802154_PAN_ID_LEN,
+		    &desc->addr.pan_id))
+		goto nla_put_failure;
+
+	if (desc->addr.mode == IEEE802154_ADDR_SHORT) {
+		if (nla_put(msg, NL802154_COORD_ADDR,
+			    IEEE802154_SHORT_ADDR_LEN,
+			    &desc->addr.short_addr))
+			goto nla_put_failure;
+	} else {
+		if (nla_put(msg, NL802154_COORD_ADDR,
+			    IEEE802154_EXTENDED_ADDR_LEN,
+			    &desc->addr.extended_addr))
+			goto nla_put_failure;
+	}
+
+	if (nla_put_u8(msg, NL802154_COORD_CHANNEL, desc->channel))
+		goto nla_put_failure;
+
+	if (nla_put_u8(msg, NL802154_COORD_PAGE, desc->page))
+		goto nla_put_failure;
+
+	if (nla_put_u16(msg, NL802154_COORD_SUPERFRAME_SPEC,
+			desc->superframe_spec))
+		goto nla_put_failure;
+
+	if (nla_put_u8(msg, NL802154_COORD_LINK_QUALITY, desc->link_quality))
+		goto nla_put_failure;
+
+	if (desc->gts_permit && nla_put_flag(msg, NL802154_COORD_GTS_PERMIT))
+		goto nla_put_failure;
+
+	/* TODO: NL802154_COORD_PAYLOAD_DATA if any */
+
+	nla_nest_end(msg, nla);
+
+	genlmsg_end(msg, hdr);
+
+	return 0;
+
+ nla_put_failure:
+	genlmsg_cancel(msg, hdr);
+
+	return -EMSGSIZE;
+}
+
+int nl802154_scan_event(struct wpan_phy *wpan_phy, struct wpan_dev *wpan_dev,
+			struct ieee802154_coord_desc *desc)
+{
+	struct cfg802154_registered_device *rdev = wpan_phy_to_rdev(wpan_phy);
+	struct sk_buff *msg;
+	int ret;
+
+	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
+	if (!msg)
+		return -ENOMEM;
+
+	ret = nl802154_prep_scan_event_msg(msg, rdev, wpan_dev, 0, 0, 0,
+					   NL802154_CMD_SCAN_EVENT,
+					   desc);
+	if (ret < 0) {
+		nlmsg_free(msg);
+		return ret;
+	}
+
+	return genlmsg_multicast_netns(&nl802154_fam, wpan_phy_net(wpan_phy),
+				       msg, 0, NL802154_MCGRP_SCAN, GFP_ATOMIC);
+}
+EXPORT_SYMBOL_GPL(nl802154_scan_event);
+
 #ifdef CONFIG_IEEE802154_NL802154_EXPERIMENTAL
 static const struct nla_policy nl802154_dev_addr_policy[NL802154_DEV_ADDR_ATTR_MAX + 1] = {
 	[NL802154_DEV_ADDR_ATTR_PAN_ID] = { .type = NLA_U16 },
diff --git a/net/ieee802154/nl802154.h b/net/ieee802154/nl802154.h
index 8c4b6d08954c..89b805500032 100644
--- a/net/ieee802154/nl802154.h
+++ b/net/ieee802154/nl802154.h
@@ -4,5 +4,7 @@
 
 int nl802154_init(void);
 void nl802154_exit(void);
+int nl802154_scan_event(struct wpan_phy *wpan_phy, struct wpan_dev *wpan_dev,
+			struct ieee802154_coord_desc *desc);
 
 #endif /* __IEEE802154_NL802154_H */