nl80211/mac80211: define and allow configuring mesh element TTL

The TTL in path selection information elements is different from
the mesh ttl used in mesh data frames.  Version 7.03 of the 11s
draft calls this ttl 'Element TTL'.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

9 files changed, 27 insertions, 7 deletions

diff --git a/include/linux/nl80211.h b/include/linux/nl80211.h
index 5cfa579df476..9e541452d805 100644
--- a/include/linux/nl80211.h
+++ b/include/linux/nl80211.h
@@ -1547,6 +1547,9 @@ enum nl80211_mntr_flags {
  * @NL80211_MESHCONF_TTL: specifies the value of TTL field set at a source mesh
  * point.
  *
+ * @NL80211_MESHCONF_ELEMENT_TTL: specifies the value of TTL field set at a
+ * source mesh point for path selection elements.
+ *
  * @NL80211_MESHCONF_AUTO_OPEN_PLINKS: whether we should automatically
  * open peer links when we detect compatible mesh peers.
  *
@@ -1593,6 +1596,7 @@ enum nl80211_meshconf_params {
         NL80211_MESHCONF_HWMP_PREQ_MIN_INTERVAL,
         NL80211_MESHCONF_HWMP_NET_DIAM_TRVS_TIME,
         NL80211_MESHCONF_HWMP_ROOTMODE,
+        NL80211_MESHCONF_ELEMENT_TTL,
 
         /* keep last */
         __NL80211_MESHCONF_ATTR_AFTER_LAST,
diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 6b2af7aeddd3..93a4b2068334 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -624,6 +624,8 @@ struct mesh_config {
         u16 dot11MeshMaxPeerLinks;
         u8  dot11MeshMaxRetries;
         u8  dot11MeshTTL;
+        /* ttl used in path selection information elements */
+        u8  element_ttl;
         bool auto_open_plinks;
         /* HWMP parameters */
         u8  dot11MeshHWMPmaxPREQretries;
diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index db134b500caa..ce6936890c26 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -1024,6 +1024,8 @@ static int ieee80211_set_mesh_params(struct wiphy *wiphy,
                 conf->dot11MeshMaxRetries = nconf->dot11MeshMaxRetries;
         if (_chg_mesh_attr(NL80211_MESHCONF_TTL, mask))
                 conf->dot11MeshTTL = nconf->dot11MeshTTL;
+        if (_chg_mesh_attr(NL80211_MESHCONF_ELEMENT_TTL, mask))
+                conf->dot11MeshTTL = nconf->element_ttl;
         if (_chg_mesh_attr(NL80211_MESHCONF_AUTO_OPEN_PLINKS, mask))
                 conf->auto_open_plinks = nconf->auto_open_plinks;
         if (_chg_mesh_attr(NL80211_MESHCONF_HWMP_MAX_PREQ_RETRIES, mask))
diff --git a/net/mac80211/debugfs_netdev.c b/net/mac80211/debugfs_netdev.c
index cbdf36d7841c..2dabdf7680d0 100644
--- a/net/mac80211/debugfs_netdev.c
+++ b/net/mac80211/debugfs_netdev.c
@@ -251,6 +251,7 @@ IEEE80211_IF_FILE(dot11MeshConfirmTimeout,
 IEEE80211_IF_FILE(dot11MeshHoldingTimeout,
                 u.mesh.mshcfg.dot11MeshHoldingTimeout, DEC);
 IEEE80211_IF_FILE(dot11MeshTTL, u.mesh.mshcfg.dot11MeshTTL, DEC);
+IEEE80211_IF_FILE(element_ttl, u.mesh.mshcfg.element_ttl, DEC);
 IEEE80211_IF_FILE(auto_open_plinks, u.mesh.mshcfg.auto_open_plinks, DEC);
 IEEE80211_IF_FILE(dot11MeshMaxPeerLinks,
                 u.mesh.mshcfg.dot11MeshMaxPeerLinks, DEC);
@@ -355,6 +356,7 @@ static void add_mesh_config(struct ieee80211_sub_if_data *sdata)
         MESHPARAMS_ADD(dot11MeshConfirmTimeout);
         MESHPARAMS_ADD(dot11MeshHoldingTimeout);
         MESHPARAMS_ADD(dot11MeshTTL);
+        MESHPARAMS_ADD(element_ttl);
         MESHPARAMS_ADD(auto_open_plinks);
         MESHPARAMS_ADD(dot11MeshMaxPeerLinks);
         MESHPARAMS_ADD(dot11MeshHWMPactivePathTimeout);
diff --git a/net/mac80211/mesh.c b/net/mac80211/mesh.c
index c8a4f19ed13b..78a36c79bdcc 100644
--- a/net/mac80211/mesh.c
+++ b/net/mac80211/mesh.c
@@ -668,6 +668,7 @@ void ieee80211_mesh_init_sdata(struct ieee80211_sub_if_data *sdata)
         ifmsh->mshcfg.dot11MeshHoldingTimeout = MESH_HOLD_T;
         ifmsh->mshcfg.dot11MeshMaxRetries = MESH_MAX_RETR;
         ifmsh->mshcfg.dot11MeshTTL = MESH_TTL;
+        ifmsh->mshcfg.element_ttl = MESH_DEFAULT_ELEMENT_TTL;
         ifmsh->mshcfg.auto_open_plinks = true;
         ifmsh->mshcfg.dot11MeshMaxPeerLinks =
                 MESH_MAX_ESTAB_PLINKS;
diff --git a/net/mac80211/mesh.h b/net/mac80211/mesh.h
index 58e741128968..182942eeac4d 100644
--- a/net/mac80211/mesh.h
+++ b/net/mac80211/mesh.h
@@ -216,6 +216,8 @@ struct mesh_rmc {
 #define PERR_RCODE_NO_ROUTE     12
 #define PERR_RCODE_DEST_UNREACH 13
 
+#define MESH_DEFAULT_ELEMENT_TTL 31
+
 /* Public interfaces */
 /* Various */
 int ieee80211_fill_mesh_addresses(struct ieee80211_hdr *hdr, __le16 *fc,
diff --git a/net/mac80211/mesh_hwmp.c b/net/mac80211/mesh_hwmp.c
index 829e08a657d0..5bf64d7112b3 100644
--- a/net/mac80211/mesh_hwmp.c
+++ b/net/mac80211/mesh_hwmp.c
@@ -232,7 +232,7 @@ int mesh_path_error_tx(u8 ttl, u8 *target, __le32 target_sn,
         *pos++ = WLAN_EID_PERR;
         *pos++ = ie_len;
         /* ttl */
-        *pos++ = MESH_TTL;
+        *pos++ = ttl;
         /* number of destinations */
         *pos++ = 1;
         /*
@@ -522,7 +522,7 @@ static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
 
         if (reply) {
                 lifetime = PREQ_IE_LIFETIME(preq_elem);
-                ttl = ifmsh->mshcfg.dot11MeshTTL;
+                ttl = ifmsh->mshcfg.element_ttl;
                 if (ttl != 0) {
                         mhwmp_dbg("replying to the PREQ\n");
                         mesh_path_sel_frame_tx(MPATH_PREP, 0, target_addr,
@@ -877,7 +877,7 @@ void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
                 sdata->u.mesh.last_sn_update = jiffies;
         }
         lifetime = default_lifetime(sdata);
-        ttl = sdata->u.mesh.mshcfg.dot11MeshTTL;
+        ttl = sdata->u.mesh.mshcfg.element_ttl;
         if (ttl == 0) {
                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
                 spin_unlock_bh(&mpath->state_lock);
@@ -1013,5 +1013,6 @@ mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata)
         mesh_path_sel_frame_tx(MPATH_RANN, 0, sdata->vif.addr,
                                cpu_to_le32(++ifmsh->sn),
                                0, NULL, 0, broadcast_addr,
-                               0, MESH_TTL, 0, 0, 0, sdata);
+                               0, sdata->u.mesh.mshcfg.element_ttl,
+                               0, 0, 0, sdata);
 }
diff --git a/net/mac80211/mesh_pathtbl.c b/net/mac80211/mesh_pathtbl.c
index 349e466cf08b..8d65b47d9837 100644
--- a/net/mac80211/mesh_pathtbl.c
+++ b/net/mac80211/mesh_pathtbl.c
@@ -467,8 +467,8 @@ void mesh_plink_broken(struct sta_info *sta)
                         mpath->flags &= ~MESH_PATH_ACTIVE;
                         ++mpath->sn;
                         spin_unlock_bh(&mpath->state_lock);
-                        mesh_path_error_tx(MESH_TTL, mpath->dst,
-                                        cpu_to_le32(mpath->sn),
+                        mesh_path_error_tx(sdata->u.mesh.mshcfg.element_ttl,
+                                        mpath->dst, cpu_to_le32(mpath->sn),
                                         cpu_to_le16(PERR_RCODE_DEST_UNREACH),
                                         bcast, sdata);
                 } else
@@ -614,7 +614,8 @@ void mesh_path_discard_frame(struct sk_buff *skb,
                 mpath = mesh_path_lookup(da, sdata);
                 if (mpath)
                         sn = ++mpath->sn;
-                mesh_path_error_tx(MESH_TTL, skb->data, cpu_to_le32(sn),
+                mesh_path_error_tx(sdata->u.mesh.mshcfg.element_ttl, skb->data,
+                                   cpu_to_le32(sn),
                                    cpu_to_le16(PERR_RCODE_NO_ROUTE), ra, sdata);
         }
 
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 960be4e650f0..0b90cab5da2f 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -2582,6 +2582,8 @@ static int nl80211_get_mesh_params(struct sk_buff *skb,
                         cur_params.dot11MeshMaxRetries);
         NLA_PUT_U8(msg, NL80211_MESHCONF_TTL,
                         cur_params.dot11MeshTTL);
+        NLA_PUT_U8(msg, NL80211_MESHCONF_ELEMENT_TTL,
+                        cur_params.element_ttl);
         NLA_PUT_U8(msg, NL80211_MESHCONF_AUTO_OPEN_PLINKS,
                         cur_params.auto_open_plinks);
         NLA_PUT_U8(msg, NL80211_MESHCONF_HWMP_MAX_PREQ_RETRIES,
@@ -2623,6 +2625,7 @@ static const struct nla_policy nl80211_meshconf_params_policy[NL80211_MESHCONF_A
         [NL80211_MESHCONF_MAX_PEER_LINKS] = { .type = NLA_U16 },
         [NL80211_MESHCONF_MAX_RETRIES] = { .type = NLA_U8 },
         [NL80211_MESHCONF_TTL] = { .type = NLA_U8 },
+        [NL80211_MESHCONF_ELEMENT_TTL] = { .type = NLA_U8 },
         [NL80211_MESHCONF_AUTO_OPEN_PLINKS] = { .type = NLA_U8 },
 
         [NL80211_MESHCONF_HWMP_MAX_PREQ_RETRIES] = { .type = NLA_U8 },
@@ -2670,6 +2673,8 @@ static int nl80211_set_mesh_params(struct sk_buff *skb, struct genl_info *info)
                         mask, NL80211_MESHCONF_MAX_RETRIES, nla_get_u8);
         FILL_IN_MESH_PARAM_IF_SET(tb, cfg, dot11MeshTTL,
                         mask, NL80211_MESHCONF_TTL, nla_get_u8);
+        FILL_IN_MESH_PARAM_IF_SET(tb, cfg, element_ttl,
+                        mask, NL80211_MESHCONF_ELEMENT_TTL, nla_get_u8);
         FILL_IN_MESH_PARAM_IF_SET(tb, cfg, auto_open_plinks,
                         mask, NL80211_MESHCONF_AUTO_OPEN_PLINKS, nla_get_u8);
         FILL_IN_MESH_PARAM_IF_SET(tb, cfg, dot11MeshHWMPmaxPREQretries,