Adding support to allow mesh HWMP to measure link metrics on unexercised
direct mesh path by sending some data frames to other mesh points which
are not currently selected as a primary traffic path but only 1 hop away.
The absence of the primary path to the chosen node makes it necessary to
apply some form of marking on a chosen packet stream so that the packets
can be properly steered to the selected node for testing, and not by the
regular mesh path lookup.

Signed-off-by: Rajkumar Manoharan <rmano...@codeaurora.org>
---
 include/net/cfg80211.h       |  6 +++++
 include/uapi/linux/nl80211.h | 16 +++++++++++++
 net/wireless/nl80211.c       | 54 ++++++++++++++++++++++++++++++++++++++++++++
 net/wireless/rdev-ops.h      | 13 +++++++++++
 net/wireless/trace.h         | 19 ++++++++++++++++
 5 files changed, 108 insertions(+)

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index e0c41eb1c860..24ee3fc3e1f5 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -3379,6 +3379,9 @@ struct cfg80211_pmsr_request {
  *     Statistics should be cumulative, currently no way to reset is provided.
  * @start_pmsr: start peer measurement (e.g. FTM)
  * @abort_pmsr: abort peer measurement
+ *
+ * @probe_mesh_link: Probe direct Mesh peer's link quality by sending data 
frame
+ *     and overrule HWMP path selection algorithm.
  */
 struct cfg80211_ops {
        int     (*suspend)(struct wiphy *wiphy, struct cfg80211_wowlan *wow);
@@ -3693,6 +3696,9 @@ struct cfg80211_ops {
                              struct cfg80211_pmsr_request *request);
        void    (*abort_pmsr)(struct wiphy *wiphy, struct wireless_dev *wdev,
                              struct cfg80211_pmsr_request *request);
+
+       int     (*probe_mesh_link)(struct wiphy *wiphy, struct net_device *dev,
+                                  const u8 *buf, size_t len);
 };
 
 /*
diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index 31ae5c7f10e3..e9184381cbdf 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -1065,6 +1065,21 @@
  *     indicated by %NL80211_ATTR_WIPHY_FREQ and other attributes
  *     determining the width and type.
  *
+ * @NL80211_CMD_PROBE_MESH_LINK: The requirement for mesh link metric
+ *     refreshing, is that from one mesh point we be able to send some data
+ *     frames to other mesh points which are not currently selected as a
+ *     primary traffic path, but which are only 1 hop away. The absence of
+ *     the primary path to the chosen node makes it necessary to apply some
+ *     form of marking on a chosen packet stream so that the packets can be
+ *     properly steered to the selected node for testing, and not by the
+ *     regular mesh path lookup. Further, the packets must be of type data
+ *     so that the rate control (often embedded in firmware) is used for
+ *     rate selection.
+ *
+ *     Here attribute %NL80211_ATTR_MAC is used to specify connected mesh
+ *     peer MAC address and %NL80211_ATTR_FRAME is used to specify the frame
+ *     content. The frame is ethernet data.
+ *
  * @NL80211_CMD_MAX: highest used command number
  * @__NL80211_CMD_AFTER_LAST: internal use
  */
@@ -1284,6 +1299,7 @@ enum nl80211_commands {
        NL80211_CMD_PEER_MEASUREMENT_COMPLETE,
 
        NL80211_CMD_NOTIFY_RADAR,
+       NL80211_CMD_PROBE_MESH_LINK,
 
        /* add new commands above here */
 
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index d91a408db113..c138bc817af8 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -13205,6 +13205,52 @@ static int nl80211_get_ftm_responder_stats(struct 
sk_buff *skb,
        return -ENOBUFS;
 }
 
+static int nl80211_probe_mesh_link(struct sk_buff *skb, struct genl_info *info)
+{
+       struct cfg80211_registered_device *rdev = info->user_ptr[0];
+       struct net_device *dev = info->user_ptr[1];
+       struct wireless_dev *wdev = dev->ieee80211_ptr;
+       struct station_info sinfo = {};
+       const u8 *buf;
+       size_t len;
+       u8 *dest;
+       int err;
+
+       if (!rdev->ops->probe_mesh_link || !rdev->ops->get_station)
+               return -EOPNOTSUPP;
+
+       if (!info->attrs[NL80211_ATTR_MAC] ||
+           !info->attrs[NL80211_ATTR_FRAME]) {
+               GENL_SET_ERR_MSG(info, "Frame or MAC missing");
+               return -EINVAL;
+       }
+
+       wdev_lock(wdev);
+       if (wdev->iftype != NL80211_IFTYPE_MESH_POINT) {
+               wdev_unlock(wdev);
+               err = -EOPNOTSUPP;
+               return err;
+       }
+       wdev_unlock(wdev);
+
+       dest = nla_data(info->attrs[NL80211_ATTR_MAC]);
+       buf = nla_data(info->attrs[NL80211_ATTR_FRAME]);
+       len = nla_len(info->attrs[NL80211_ATTR_FRAME]);
+
+       if (len < sizeof(struct ethhdr))
+               return -EINVAL;
+
+       if (!ether_addr_equal(buf, dest) || is_multicast_ether_addr(buf) ||
+           !ether_addr_equal(buf + ETH_ALEN, dev->dev_addr))
+               return -EINVAL;
+
+       err = rdev_get_station(rdev, dev, dest, &sinfo);
+       if (err)
+               return err;
+
+       return rdev_probe_mesh_link(rdev, dev, dest, buf, len);
+}
+
 #define NL80211_FLAG_NEED_WIPHY                0x01
 #define NL80211_FLAG_NEED_NETDEV       0x02
 #define NL80211_FLAG_NEED_RTNL         0x04
@@ -14139,6 +14185,14 @@ static void nl80211_post_doit(const struct genl_ops 
*ops, struct sk_buff *skb,
                .internal_flags = NL80211_FLAG_NEED_NETDEV_UP |
                                  NL80211_FLAG_NEED_RTNL,
        },
+       {
+               .cmd = NL80211_CMD_PROBE_MESH_LINK,
+               .doit = nl80211_probe_mesh_link,
+               .policy = nl80211_policy,
+               .flags = GENL_UNS_ADMIN_PERM,
+               .internal_flags = NL80211_FLAG_NEED_NETDEV_UP |
+                                 NL80211_FLAG_NEED_RTNL,
+       },
 };
 
 static struct genl_family nl80211_fam __ro_after_init = {
diff --git a/net/wireless/rdev-ops.h b/net/wireless/rdev-ops.h
index 5cb48d135fab..ec1b4800872f 100644
--- a/net/wireless/rdev-ops.h
+++ b/net/wireless/rdev-ops.h
@@ -1272,4 +1272,17 @@ static inline int rdev_del_pmk(struct 
cfg80211_registered_device *rdev,
        trace_rdev_return_void(&rdev->wiphy);
 }
 
+static inline int
+rdev_probe_mesh_link(struct cfg80211_registered_device *rdev,
+                    struct net_device *dev, const u8 *dest,
+                    const void *buf, size_t len)
+{
+       int ret;
+
+       trace_rdev_probe_mesh_link(&rdev->wiphy, dev, dest, buf, len);
+       ret = rdev->ops->probe_mesh_link(&rdev->wiphy, dev, buf, len);
+       trace_rdev_return_int(&rdev->wiphy, ret);
+       return ret;
+}
+
 #endif /* __CFG80211_RDEV_OPS */
diff --git a/net/wireless/trace.h b/net/wireless/trace.h
index 44b2ce1bb13a..274a844c7ea9 100644
--- a/net/wireless/trace.h
+++ b/net/wireless/trace.h
@@ -3362,6 +3362,25 @@
                  WIPHY_PR_ARG, WDEV_PR_ARG,
                  (unsigned long long)__entry->cookie)
 );
+
+TRACE_EVENT(rdev_probe_mesh_link,
+       TP_PROTO(struct wiphy *wiphy, struct net_device *netdev,
+                const u8 *dest, const u8 *buf, size_t len),
+       TP_ARGS(wiphy, netdev, dest, buf, len),
+       TP_STRUCT__entry(
+               WIPHY_ENTRY
+               NETDEV_ENTRY
+               MAC_ENTRY(dest)
+       ),
+       TP_fast_assign(
+               WIPHY_ASSIGN;
+               NETDEV_ASSIGN;
+               MAC_ASSIGN(dest, dest);
+       ),
+       TP_printk(WIPHY_PR_FMT ", " NETDEV_PR_FMT ", " MAC_PR_FMT,
+                 WIPHY_PR_ARG, NETDEV_PR_ARG, MAC_PR_ARG(dest))
+);
+
 #endif /* !__RDEV_OPS_TRACE || TRACE_HEADER_MULTI_READ */
 
 #undef TRACE_INCLUDE_PATH
-- 
1.9.1

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