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 <[email protected]>
Signed-off-by: John W. Linville <[email protected]>

Author: Javier Cardona

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,

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;

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))

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);

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;

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,

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);
 }

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);
 	}
 

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,