// SPDX-License-Identifier: GPL-2.0-only /* * Copyright (c) 2008, 2009 open80211s Ltd. * Copyright (C) 2019 Intel Corporation * Author: Luis Carlos Cobo */ #include #include #include #include "wme.h" #include "mesh.h" #define TEST_FRAME_LEN 8192 #define MAX_METRIC 0xffffffff #define ARITH_SHIFT 8 #define LINK_FAIL_THRESH 95 #define MAX_PREQ_QUEUE_LEN 64 static void mesh_queue_preq(struct mesh_path *, u8); static inline u32 u32_field_get(const u8 *preq_elem, int offset, bool ae) { if (ae) offset += 6; return get_unaligned_le32(preq_elem + offset); } static inline u16 u16_field_get(const u8 *preq_elem, int offset, bool ae) { if (ae) offset += 6; return get_unaligned_le16(preq_elem + offset); } /* HWMP IE processing macros */ #define AE_F (1<<6) #define AE_F_SET(x) (*x & AE_F) #define PREQ_IE_FLAGS(x) (*(x)) #define PREQ_IE_HOPCOUNT(x) (*(x + 1)) #define PREQ_IE_TTL(x) (*(x + 2)) #define PREQ_IE_PREQ_ID(x) u32_field_get(x, 3, 0) #define PREQ_IE_ORIG_ADDR(x) (x + 7) #define PREQ_IE_ORIG_SN(x) u32_field_get(x, 13, 0) #define PREQ_IE_LIFETIME(x) u32_field_get(x, 17, AE_F_SET(x)) #define PREQ_IE_METRIC(x) u32_field_get(x, 21, AE_F_SET(x)) #define PREQ_IE_TARGET_F(x) (*(AE_F_SET(x) ? x + 32 : x + 26)) #define PREQ_IE_TARGET_ADDR(x) (AE_F_SET(x) ? x + 33 : x + 27) #define PREQ_IE_TARGET_SN(x) u32_field_get(x, 33, AE_F_SET(x)) #define PREP_IE_FLAGS(x) PREQ_IE_FLAGS(x) #define PREP_IE_HOPCOUNT(x) PREQ_IE_HOPCOUNT(x) #define PREP_IE_TTL(x) PREQ_IE_TTL(x) #define PREP_IE_ORIG_ADDR(x) (AE_F_SET(x) ? x + 27 : x + 21) #define PREP_IE_ORIG_SN(x) u32_field_get(x, 27, AE_F_SET(x)) #define PREP_IE_LIFETIME(x) u32_field_get(x, 13, AE_F_SET(x)) #define PREP_IE_METRIC(x) u32_field_get(x, 17, AE_F_SET(x)) #define PREP_IE_TARGET_ADDR(x) (x + 3) #define PREP_IE_TARGET_SN(x) u32_field_get(x, 9, 0) #define PERR_IE_TTL(x) (*(x)) #define PERR_IE_TARGET_FLAGS(x) (*(x + 2)) #define PERR_IE_TARGET_ADDR(x) (x + 3) #define PERR_IE_TARGET_SN(x) u32_field_get(x, 9, 0) #define PERR_IE_TARGET_RCODE(x) u16_field_get(x, 13, 0) #define MSEC_TO_TU(x) (x*1000/1024) #define SN_GT(x, y) ((s32)(y - x) < 0) #define SN_LT(x, y) ((s32)(x - y) < 0) #define MAX_SANE_SN_DELTA 32 static inline u32 SN_DELTA(u32 x, u32 y) { return x >= y ? x - y : y - x; } #define net_traversal_jiffies(s) \ msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPnetDiameterTraversalTime) #define default_lifetime(s) \ MSEC_TO_TU(s->u.mesh.mshcfg.dot11MeshHWMPactivePathTimeout) #define min_preq_int_jiff(s) \ (msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPpreqMinInterval)) #define max_preq_retries(s) (s->u.mesh.mshcfg.dot11MeshHWMPmaxPREQretries) #define disc_timeout_jiff(s) \ msecs_to_jiffies(sdata->u.mesh.mshcfg.min_discovery_timeout) #define root_path_confirmation_jiffies(s) \ msecs_to_jiffies(sdata->u.mesh.mshcfg.dot11MeshHWMPconfirmationInterval) enum mpath_frame_type { MPATH_PREQ = 0, MPATH_PREP, MPATH_PERR, MPATH_RANN }; static const u8 broadcast_addr[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff}; static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags, const u8 *orig_addr, u32 orig_sn, u8 target_flags, const u8 *target, u32 target_sn, const u8 *da, u8 hop_count, u8 ttl, u32 lifetime, u32 metric, u32 preq_id, struct ieee80211_sub_if_data *sdata) { struct ieee80211_local *local = sdata->local; struct sk_buff *skb; struct ieee80211_mgmt *mgmt; u8 *pos, ie_len; int hdr_len = offsetofend(struct ieee80211_mgmt, u.action.u.mesh_action); skb = dev_alloc_skb(local->tx_headroom + hdr_len + 2 + 37); /* max HWMP IE */ if (!skb) return -1; skb_reserve(skb, local->tx_headroom); mgmt = skb_put_zero(skb, hdr_len); mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT | IEEE80211_STYPE_ACTION); memcpy(mgmt->da, da, ETH_ALEN); memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN); /* BSSID == SA */ memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN); mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION; mgmt->u.action.u.mesh_action.action_code = WLAN_MESH_ACTION_HWMP_PATH_SELECTION; switch (action) { case MPATH_PREQ: mhwmp_dbg(sdata, "sending PREQ to %pM\n", target); ie_len = 37; pos = skb_put(skb, 2 + ie_len); *pos++ = WLAN_EID_PREQ; break; case MPATH_PREP: mhwmp_dbg(sdata, "sending PREP to %pM\n", orig_addr); ie_len = 31; pos = skb_put(skb, 2 + ie_len); *pos++ = WLAN_EID_PREP; break; case MPATH_RANN: mhwmp_dbg(sdata, "sending RANN from %pM\n", orig_addr); ie_len = sizeof(struct ieee80211_rann_ie); pos = skb_put(skb, 2 + ie_len); *pos++ = WLAN_EID_RANN; break; default: kfree_skb(skb); return -ENOTSUPP; } *pos++ = ie_len; *pos++ = flags; *pos++ = hop_count; *pos++ = ttl; if (action == MPATH_PREP) { memcpy(pos, target, ETH_ALEN); pos += ETH_ALEN; put_unaligned_le32(target_sn, pos); pos += 4; } else { if (action == MPATH_PREQ) { put_unaligned_le32(preq_id, pos); pos += 4; } memcpy(pos, orig_addr, ETH_ALEN); pos += ETH_ALEN; put_unaligned_le32(orig_sn, pos); pos += 4; } put_unaligned_le32(lifetime, pos); /* interval for RANN */ pos += 4; put_unaligned_le32(metric, pos); pos += 4; if (action == MPATH_PREQ) { *pos++ = 1; /* destination count */ *pos++ = target_flags; memcpy(pos, target, ETH_ALEN); pos += ETH_ALEN; put_unaligned_le32(target_sn, pos); pos += 4; } else if (action == MPATH_PREP) { memcpy(pos, orig_addr, ETH_ALEN); pos += ETH_ALEN; put_unaligned_le32(orig_sn, pos); pos += 4; } ieee80211_tx_skb(sdata, skb); return 0; } /* Headroom is not adjusted. Caller should ensure that skb has sufficient * headroom in case the frame is encrypted. */ static void prepare_frame_for_deferred_tx(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb) { struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; skb_reset_mac_header(skb); skb_reset_network_header(skb); skb_reset_transport_header(skb); /* Send all internal mgmt frames on VO. Accordingly set TID to 7. */ skb_set_queue_mapping(skb, IEEE80211_AC_VO); skb->priority = 7; info->control.vif = &sdata->vif; info->control.flags |= IEEE80211_TX_INTCFL_NEED_TXPROCESSING; ieee80211_set_qos_hdr(sdata, skb); ieee80211_mps_set_frame_flags(sdata, NULL, hdr); } /** * mesh_path_error_tx - Sends a PERR mesh management frame * * @ttl: allowed remaining hops * @target: broken destination * @target_sn: SN of the broken destination * @target_rcode: reason code for this PERR * @ra: node this frame is addressed to * @sdata: local mesh subif * * Note: This function may be called with driver locks taken that the driver * also acquires in the TX path. To avoid a deadlock we don't transmit the * frame directly but add it to the pending queue instead. */ int mesh_path_error_tx(struct ieee80211_sub_if_data *sdata, u8 ttl, const u8 *target, u32 target_sn, u16 target_rcode, const u8 *ra) { struct ieee80211_local *local = sdata->local; struct sk_buff *skb; struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh; struct ieee80211_mgmt *mgmt; u8 *pos, ie_len; int hdr_len = offsetofend(struct ieee80211_mgmt, u.action.u.mesh_action); if (time_before(jiffies, ifmsh->next_perr)) return -EAGAIN; skb = dev_alloc_skb(local->tx_headroom + sdata->encrypt_headroom + IEEE80211_ENCRYPT_TAILROOM + hdr_len + 2 + 15 /* PERR IE */); if (!skb) return -1; skb_reserve(skb, local->tx_headroom + sdata->encrypt_headroom); mgmt = skb_put_zero(skb, hdr_len); mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT | IEEE80211_STYPE_ACTION); memcpy(mgmt->da, ra, ETH_ALEN); memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN); /* BSSID == SA */ memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN); mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION; mgmt->u.action.u.mesh_action.action_code = WLAN_MESH_ACTION_HWMP_PATH_SELECTION; ie_len = 15; pos = skb_put(skb, 2 + ie_len); *pos++ = WLAN_EID_PERR; *pos++ = ie_len; /* ttl */ *pos++ = ttl; /* number of destinations */ *pos++ = 1; /* Flags field has AE bit only as defined in * sec 8.4.2.117 IEEE802.11-2012 */ *pos = 0; pos++; memcpy(pos, target, ETH_ALEN); pos += ETH_ALEN; put_unaligned_le32(target_sn, pos); pos += 4; put_unaligned_le16(target_rcode, pos); /* see note in function header */ prepare_frame_for_deferred_tx(sdata, skb); ifmsh->next_perr = TU_TO_EXP_TIME( ifmsh->mshcfg.dot11MeshHWMPperrMinInterval); ieee80211_add_pending_skb(local, skb); return 0; } void ieee80211s_update_metric(struct ieee80211_local *local, struct sta_info *sta, struct ieee80211_tx_status *st) { struct ieee80211_tx_info *txinfo = st->info; int failed; struct rate_info rinfo; failed = !(txinfo->flags & IEEE80211_TX_STAT_ACK); /* moving average, scaled to 100. * feed failure as 100 and success as 0 */ ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, failed * 100); if (ewma_mesh_fail_avg_read(&sta->mesh->fail_avg) > LINK_FAIL_THRESH) mesh_plink_broken(sta); sta_set_rate_info_tx(sta, &sta->tx_stats.last_rate, &rinfo); ewma_mesh_tx_rate_avg_add(&sta->mesh->tx_rate_avg, cfg80211_calculate_bitrate(&rinfo)); } u32 airtime_link_metric_get(struct ieee80211_local *local, struct sta_info *sta) { /* This should be adjusted for each device */ int device_constant = 1 << ARITH_SHIFT; int test_frame_len = TEST_FRAME_LEN << ARITH_SHIFT; int s_unit = 1 << ARITH_SHIFT; int rate, err; u32 tx_time, estimated_retx; u64 result; unsigned long fail_avg = ewma_mesh_fail_avg_read(&sta->mesh->fail_avg); if (sta->mesh->plink_state != NL80211_PLINK_ESTAB) return MAX_METRIC; /* Try to get rate based on HW/SW RC algorithm. * Rate is returned in units of Kbps, correct this * to comply with airtime calculation units * Round up in case we get rate < 100Kbps */ rate = DIV_ROUND_UP(sta_get_expected_throughput(sta), 100); if (rate) { err = 0; } else { if (fail_avg > LINK_FAIL_THRESH) return MAX_METRIC; rate = ewma_mesh_tx_rate_avg_read(&sta->mesh->tx_rate_avg); if (WARN_ON(!rate)) return MAX_METRIC; err = (fail_avg << ARITH_SHIFT) / 100; } /* bitrate is in units of 100 Kbps, while we need rate in units of * 1Mbps. This will be corrected on tx_time computation. */ tx_time = (device_constant + 10 * test_frame_len / rate); estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err)); result = ((u64)tx_time * estimated_retx) >> (2 * ARITH_SHIFT); return (u32)result; } /** * hwmp_route_info_get - Update routing info to originator and transmitter * * @sdata: local mesh subif * @mgmt: mesh management frame * @hwmp_ie: hwmp information element (PREP or PREQ) * @action: type of hwmp ie * * This function updates the path routing information to the originator and the * transmitter of a HWMP PREQ or PREP frame. * * Returns: metric to frame originator or 0 if the frame should not be further * processed * * Notes: this function is the only place (besides user-provided info) where * path routing information is updated. */ static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata, struct ieee80211_mgmt *mgmt, const u8 *hwmp_ie, enum mpath_frame_type action) { struct ieee80211_local *local = sdata->local; struct mesh_path *mpath; struct sta_info *sta; bool fresh_info; const u8 *orig_addr, *ta; u32 orig_sn, orig_metric; unsigned long orig_lifetime, exp_time; u32 last_hop_metric, new_metric; bool process = true; u8 hopcount; rcu_read_lock(); sta = sta_info_get(sdata, mgmt->sa); if (!sta) { rcu_read_unlock(); return 0; } last_hop_metric = airtime_link_metric_get(local, sta); /* Update and check originator routing info */ fresh_info = true; switch (action) { case MPATH_PREQ: orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie); orig_sn = PREQ_IE_ORIG_SN(hwmp_ie); orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie); orig_metric = PREQ_IE_METRIC(hwmp_ie); hopcount = PREQ_IE_HOPCOUNT(hwmp_ie) + 1; break; case MPATH_PREP: /* Originator here refers to the MP that was the target in the * Path Request. We divert from the nomenclature in the draft * so that we can easily use a single function to gather path * information from both PREQ and PREP frames. */ orig_addr = PREP_IE_TARGET_ADDR(hwmp_ie); orig_sn = PREP_IE_TARGET_SN(hwmp_ie); orig_lifetime = PREP_IE_LIFETIME(hwmp_ie); orig_metric = PREP_IE_METRIC(hwmp_ie); hopcount = PREP_IE_HOPCOUNT(hwmp_ie) + 1; break; default: rcu_read_unlock(); return 0; } new_metric = orig_metric + last_hop_metric; if (new_metric < orig_metric) new_metric = MAX_METRIC; exp_time = TU_TO_EXP_TIME(orig_lifetime); if (ether_addr_equal(orig_addr, sdata->vif.addr)) { /* This MP is the originator, we are not interested in this * frame, except for updating transmitter's path info. */ process = false; fresh_info = false; } else { mpath = mesh_path_lookup(sdata, orig_addr); if (mpath) { spin_lock_bh(&mpath->state_lock); if (mpath->flags & MESH_PATH_FIXED) fresh_info = false; else if ((mpath->flags & MESH_PATH_ACTIVE) && (mpath->flags & MESH_PATH_SN_VALID)) { if (SN_GT(mpath->sn, orig_sn) || (mpath->sn == orig_sn && (rcu_access_pointer(mpath->next_hop) != sta ? mult_frac(new_metric, 10, 9) : new_metric) >= mpath->metric)) { process = false; fresh_info = false; } } else if (!(mpath->flags & MESH_PATH_ACTIVE)) { bool have_sn, newer_sn, bounced; have_sn = mpath->flags & MESH_PATH_SN_VALID; newer_sn = have_sn && SN_GT(orig_sn, mpath->sn); bounced = have_sn && (SN_DELTA(orig_sn, mpath->sn) > MAX_SANE_SN_DELTA); if (!have_sn || newer_sn) { /* if SN is newer than what we had * then we can take it */; } else if (bounced) { /* if SN is way different than what * we had then assume the other side * rebooted or restarted */; } else { process = false; fresh_info = false; } } } else { mpath = mesh_path_add(sdata, orig_addr); if (IS_ERR(mpath)) { rcu_read_unlock(); return 0; } spin_lock_bh(&mpath->state_lock); } if (fresh_info) { if (rcu_access_pointer(mpath->next_hop) != sta) mpath->path_change_count++; mesh_path_assign_nexthop(mpath, sta); mpath->flags |= MESH_PATH_SN_VALID; mpath->metric = new_metric; mpath->sn = orig_sn; mpath->exp_time = time_after(mpath->exp_time, exp_time) ? mpath->exp_time : exp_time; mpath->hop_count = hopcount; mesh_path_activate(mpath); spin_unlock_bh(&mpath->state_lock); ewma_mesh_fail_avg_init(&sta->mesh->fail_avg); /* init it at a low value - 0 start is tricky */ ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, 1); mesh_path_tx_pending(mpath); /* draft says preq_id should be saved to, but there does * not seem to be any use for it, skipping by now */ } else spin_unlock_bh(&mpath->state_lock); } /* Update and check transmitter routing info */ ta = mgmt->sa; if (ether_addr_equal(orig_addr, ta)) fresh_info = false; else { fresh_info = true; mpath = mesh_path_lookup(sdata, ta); if (mpath) { spin_lock_bh(&mpath->state_lock); if ((mpath->flags & MESH_PATH_FIXED) || ((mpath->flags & MESH_PATH_ACTIVE) && ((rcu_access_pointer(mpath->next_hop) != sta ? mult_frac(last_hop_metric, 10, 9) : last_hop_metric) > mpath->metric))) fresh_info = false; } else { mpath = mesh_path_add(sdata, ta); if (IS_ERR(mpath)) { rcu_read_unlock(); return 0; } spin_lock_bh(&mpath->state_lock); } if (fresh_info) { if (rcu_access_pointer(mpath->next_hop) != sta) mpath->path_change_count++; mesh_path_assign_nexthop(mpath, sta); mpath->metric = last_hop_metric; mpath->exp_time = time_after(mpath->exp_time, exp_time) ? mpath->exp_time : exp_time; mpath->hop_count = 1; mesh_path_activate(mpath); spin_unlock_bh(&mpath->state_lock); ewma_mesh_fail_avg_init(&sta->mesh->fail_avg); /* init it at a low value - 0 start is tricky */ ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, 1); mesh_path_tx_pending(mpath); } else spin_unlock_bh(&mpath->state_lock); } rcu_read_unlock(); return process ? new_metric : 0; } static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata, struct ieee80211_mgmt *mgmt, const u8 *preq_elem, u32 orig_metric) { struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh; struct mesh_path *mpath = NULL; const u8 *target_addr, *orig_addr; const u8 *da; u8 target_flags, ttl, flags; u32 orig_sn, target_sn, lifetime, target_metric = 0; bool reply = false; bool forward = true; bool root_is_gate; /* Update target SN, if present */ target_addr = PREQ_IE_TARGET_ADDR(preq_elem); orig_addr = PREQ_IE_ORIG_ADDR(preq_elem); target_sn = PREQ_IE_TARGET_SN(preq_elem); orig_sn = PREQ_IE_ORIG_SN(preq_elem); target_flags = PREQ_IE_TARGET_F(preq_elem); /* Proactive PREQ gate announcements */ flags = PREQ_IE_FLAGS(preq_elem); root_is_gate = !!(flags & RANN_FLAG_IS_GATE); mhwmp_dbg(sdata, "received PREQ from %pM\n", orig_addr); if (ether_addr_equal(target_addr, sdata->vif.addr)) { mhwmp_dbg(sdata, "PREQ is for us\n"); forward = false; reply = true; target_metric = 0; if (SN_GT(target_sn, ifmsh->sn)) ifmsh->sn = target_sn; if (time_after(jiffies, ifmsh->last_sn_update + net_traversal_jiffies(sdata)) || time_before(jiffies, ifmsh->last_sn_update)) { ++ifmsh->sn; ifmsh->last_sn_update = jiffies; } target_sn = ifmsh->sn; } else if (is_broadcast_ether_addr(target_addr) && (target_flags & IEEE80211_PREQ_TO_FLAG)) { rcu_read_lock(); mpath = mesh_path_lookup(sdata, orig_addr); if (mpath) { if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) { reply = true; target_addr = sdata->vif.addr; target_sn = ++ifmsh->sn; target_metric = 0; ifmsh->last_sn_update = jiffies; } if (root_is_gate) mesh_path_add_gate(mpath); } rcu_read_unlock(); } else { rcu_read_lock(); mpath = mesh_path_lookup(sdata, target_addr); if (mpath) { if ((!(mpath->flags & MESH_PATH_SN_VALID)) || SN_LT(mpath->sn, target_sn)) { mpath->sn = target_sn; mpath->flags |= MESH_PATH_SN_VALID; } else if ((!(target_flags & IEEE80211_PREQ_TO_FLAG)) && (mpath->flags & MESH_PATH_ACTIVE)) { reply = true; target_metric = mpath->metric; target_sn = mpath->sn; /* Case E2 of sec 13.10.9.3 IEEE 802.11-2012*/ target_flags |= IEEE80211_PREQ_TO_FLAG; } } rcu_read_unlock(); } if (reply) { lifetime = PREQ_IE_LIFETIME(preq_elem); ttl = ifmsh->mshcfg.element_ttl; if (ttl != 0) { mhwmp_dbg(sdata, "replying to the PREQ\n"); mesh_path_sel_frame_tx(MPATH_PREP, 0, orig_addr, orig_sn, 0, target_addr, target_sn, mgmt->sa, 0, ttl, lifetime, target_metric, 0, sdata); } else { ifmsh->mshstats.dropped_frames_ttl++; } } if (forward && ifmsh->mshcfg.dot11MeshForwarding) { u32 preq_id; u8 hopcount; ttl = PREQ_IE_TTL(preq_elem); lifetime = PREQ_IE_LIFETIME(preq_elem); if (ttl <= 1) { ifmsh->mshstats.dropped_frames_ttl++; return; } mhwmp_dbg(sdata, "forwarding the PREQ from %pM\n", orig_addr); --ttl; preq_id = PREQ_IE_PREQ_ID(preq_elem); hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1; da = (mpath && mpath->is_root) ? mpath->rann_snd_addr : broadcast_addr; if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) { target_addr = PREQ_IE_TARGET_ADDR(preq_elem); target_sn = PREQ_IE_TARGET_SN(preq_elem); } mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr, orig_sn, target_flags, target_addr, target_sn, da, hopcount, ttl, lifetime, orig_metric, preq_id, sdata); if (!is_multicast_ether_addr(da)) ifmsh->mshstats.fwded_unicast++; else ifmsh->mshstats.fwded_mcast++; ifmsh->mshstats.fwded_frames++; } } static inline struct sta_info * next_hop_deref_protected(struct mesh_path *mpath) { return rcu_dereference_protected(mpath->next_hop, lockdep_is_held(&mpath->state_lock)); } static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata, struct ieee80211_mgmt *mgmt, const u8 *prep_elem, u32 metric) { struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh; struct mesh_path *mpath; const u8 *target_addr, *orig_addr; u8 ttl, hopcount, flags; u8 next_hop[ETH_ALEN]; u32 target_sn, orig_sn, lifetime; mhwmp_dbg(sdata, "received PREP from %pM\n", PREP_IE_TARGET_ADDR(prep_elem)); orig_addr = PREP_IE_ORIG_ADDR(prep_elem); if (ether_addr_equal(orig_addr, sdata->vif.addr)) /* destination, no forwarding required */ return; if (!ifmsh->mshcfg.dot11MeshForwarding) return; ttl = PREP_IE_TTL(prep_elem); if (ttl <= 1) { sdata->u.mesh.mshstats.dropped_frames_ttl++; return; } rcu_read_lock(); mpath = mesh_path_lookup(sdata, orig_addr); if (mpath) spin_lock_bh(&mpath->state_lock); else goto fail; if (!(mpath->flags & MESH_PATH_ACTIVE)) { spin_unlock_bh(&mpath->state_lock); goto fail; } memcpy(next_hop, next_hop_deref_protected(mpath)->sta.addr, ETH_ALEN); spin_unlock_bh(&mpath->state_lock); --ttl; flags = PREP_IE_FLAGS(prep_elem); lifetime = PREP_IE_LIFETIME(prep_elem); hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1; target_addr = PREP_IE_TARGET_ADDR(prep_elem); target_sn = PREP_IE_TARGET_SN(prep_elem); orig_sn = PREP_IE_ORIG_SN(prep_elem); mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr, orig_sn, 0, target_addr, target_sn, next_hop, hopcount, ttl, lifetime, metric, 0, sdata); rcu_read_unlock(); sdata->u.mesh.mshstats.fwded_unicast++; sdata->u.mesh.mshstats.fwded_frames++; return; fail: rcu_read_unlock(); sdata->u.mesh.mshstats.dropped_frames_no_route++; } static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata, struct ieee80211_mgmt *mgmt, const u8 *perr_elem) { struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh; struct mesh_path *mpath; u8 ttl; const u8 *ta, *target_addr; u32 target_sn; u16 target_rcode; ta = mgmt->sa; ttl = PERR_IE_TTL(perr_elem); if (ttl <= 1) { ifmsh->mshstats.dropped_frames_ttl++; return; } ttl--; target_addr = PERR_IE_TARGET_ADDR(perr_elem); target_sn = PERR_IE_TARGET_SN(perr_elem); target_rcode = PERR_IE_TARGET_RCODE(perr_elem); rcu_read_lock(); mpath = mesh_path_lookup(sdata, target_addr); if (mpath) { struct sta_info *sta; spin_lock_bh(&mpath->state_lock); sta = next_hop_deref_protected(mpath); if (mpath->flags & MESH_PATH_ACTIVE && ether_addr_equal(ta, sta->sta.addr) && !(mpath->flags & MESH_PATH_FIXED) && (!(mpath->flags & MESH_PATH_SN_VALID) || SN_GT(target_sn, mpath->sn) || target_sn == 0)) { mpath->flags &= ~MESH_PATH_ACTIVE; if (target_sn != 0) mpath->sn = target_sn; else mpath->sn += 1; spin_unlock_bh(&mpath->state_lock); if (!ifmsh->mshcfg.dot11MeshForwarding) goto endperr; mesh_path_error_tx(sdata, ttl, target_addr, target_sn, target_rcode, broadcast_addr); } else spin_unlock_bh(&mpath->state_lock); } endperr: rcu_read_unlock(); } static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata, struct ieee80211_mgmt *mgmt, const struct ieee80211_rann_ie *rann) { struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh; struct ieee80211_local *local = sdata->local; struct sta_info *sta; struct mesh_path *mpath; u8 ttl, flags, hopcount; const u8 *orig_addr; u32 orig_sn, new_metric, orig_metric, last_hop_metric, interval; bool root_is_gate; ttl = rann->rann_ttl; flags = rann->rann_flags; root_is_gate = !!(flags & RANN_FLAG_IS_GATE); orig_addr = rann->rann_addr; orig_sn = le32_to_cpu(rann->rann_seq); interval = le32_to_cpu(rann->rann_interval); hopcount = rann->rann_hopcount; hopcount++; orig_metric = le32_to_cpu(rann->rann_metric); /* Ignore our own RANNs */ if (ether_addr_equal(orig_addr, sdata->vif.addr)) return; mhwmp_dbg(sdata, "received RANN from %pM via neighbour %pM (is_gate=%d)\n", orig_addr, mgmt->sa, root_is_gate); rcu_read_lock(); sta = sta_info_get(sdata, mgmt->sa); if (!sta) { rcu_read_unlock(); return; } last_hop_metric = airtime_link_metric_get(local, sta); new_metric = orig_metric + last_hop_metric; if (new_metric < orig_metric) new_metric = MAX_METRIC; mpath = mesh_path_lookup(sdata, orig_addr); if (!mpath) { mpath = mesh_path_add(sdata, orig_addr); if (IS_ERR(mpath)) { rcu_read_unlock(); sdata->u.mesh.mshstats.dropped_frames_no_route++; return; } } if (!(SN_LT(mpath->sn, orig_sn)) && !(mpath->sn == orig_sn && new_metric < mpath->rann_metric)) { rcu_read_unlock(); return; } if ((!(mpath->flags & (MESH_PATH_ACTIVE | MESH_PATH_RESOLVING)) || (time_after(jiffies, mpath->last_preq_to_root + root_path_confirmation_jiffies(sdata)) || time_before(jiffies, mpath->last_preq_to_root))) && !(mpath->flags & MESH_PATH_FIXED) && (ttl != 0)) { mhwmp_dbg(sdata, "time to refresh root mpath %pM\n", orig_addr); mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH); mpath->last_preq_to_root = jiffies; } mpath->sn = orig_sn; mpath->rann_metric = new_metric; mpath->is_root = true; /* Recording RANNs sender address to send individually * addressed PREQs destined for root mesh STA */ memcpy(mpath->rann_snd_addr, mgmt->sa, ETH_ALEN); if (root_is_gate) mesh_path_add_gate(mpath); if (ttl <= 1) { ifmsh->mshstats.dropped_frames_ttl++; rcu_read_unlock(); return; } ttl--; if (ifmsh->mshcfg.dot11MeshForwarding) { mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr, orig_sn, 0, NULL, 0, broadcast_addr, hopcount, ttl, interval, new_metric, 0, sdata); } rcu_read_unlock(); } void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata, struct ieee80211_mgmt *mgmt, size_t len) { struct ieee802_11_elems elems; size_t baselen; u32 path_metric; struct sta_info *sta; /* need action_code */ if (len < IEEE80211_MIN_ACTION_SIZE + 1) return; rcu_read_lock(); sta = sta_info_get(sdata, mgmt->sa); if (!sta || sta->mesh->plink_state != NL80211_PLINK_ESTAB) { rcu_read_unlock(); return; } rcu_read_unlock(); baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt; ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable, len - baselen, false, &elems, mgmt->bssid, NULL); if (elems.preq) { if (elems.preq_len != 37) /* Right now we support just 1 destination and no AE */ return; path_metric = hwmp_route_info_get(sdata, mgmt, elems.preq, MPATH_PREQ); if (path_metric) hwmp_preq_frame_process(sdata, mgmt, elems.preq, path_metric); } if (elems.prep) { if (elems.prep_len != 31) /* Right now we support no AE */ return; path_metric = hwmp_route_info_get(sdata, mgmt, elems.prep, MPATH_PREP); if (path_metric) hwmp_prep_frame_process(sdata, mgmt, elems.prep, path_metric); } if (elems.perr) { if (elems.perr_len != 15) /* Right now we support only one destination per PERR */ return; hwmp_perr_frame_process(sdata, mgmt, elems.perr); } if (elems.rann) hwmp_rann_frame_process(sdata, mgmt, elems.rann); } /** * mesh_queue_preq - queue a PREQ to a given destination * * @mpath: mesh path to discover * @flags: special attributes of the PREQ to be sent * * Locking: the function must be called from within a rcu read lock block. * */ static void mesh_queue_preq(struct mesh_path *mpath, u8 flags) { struct ieee80211_sub_if_data *sdata = mpath->sdata; struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh; struct mesh_preq_queue *preq_node; preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC); if (!preq_node) { mhwmp_dbg(sdata, "could not allocate PREQ node\n"); return; } spin_lock_bh(&ifmsh->mesh_preq_queue_lock); if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) { spin_unlock_bh(&ifmsh->mesh_preq_queue_lock); kfree(preq_node); if (printk_ratelimit()) mhwmp_dbg(sdata, "PREQ node queue full\n"); return; } spin_lock(&mpath->state_lock); if (mpath->flags & MESH_PATH_REQ_QUEUED) { spin_unlock(&mpath->state_lock); spin_unlock_bh(&ifmsh->mesh_preq_queue_lock); kfree(preq_node); return; } memcpy(preq_node->dst, mpath->dst, ETH_ALEN); preq_node->flags = flags; mpath->flags |= MESH_PATH_REQ_QUEUED; spin_unlock(&mpath->state_lock); list_add_tail(&preq_node->list, &ifmsh->preq_queue.list); ++ifmsh->preq_queue_len; spin_unlock_bh(&ifmsh->mesh_preq_queue_lock); if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata))) ieee80211_queue_work(&sdata->local->hw, &sdata->work); else if (time_before(jiffies, ifmsh->last_preq)) { /* avoid long wait if did not send preqs for a long time * and jiffies wrapped around */ ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1; ieee80211_queue_work(&sdata->local->hw, &sdata->work); } else mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq + min_preq_int_jiff(sdata)); } /** * mesh_path_start_discovery - launch a path discovery from the PREQ queue * * @sdata: local mesh subif */ void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata) { struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh; struct mesh_preq_queue *preq_node; struct mesh_path *mpath; u8 ttl, target_flags = 0; const u8 *da; u32 lifetime; spin_lock_bh(&ifmsh->mesh_preq_queue_lock); if (!ifmsh->preq_queue_len || time_before(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata))) { spin_unlock_bh(&ifmsh->mesh_preq_queue_lock); return; } preq_node = list_first_entry(&ifmsh->preq_queue.list, struct mesh_preq_queue, list); list_del(&preq_node->list); --ifmsh->preq_queue_len; spin_unlock_bh(&ifmsh->mesh_preq_queue_lock); rcu_read_lock(); mpath = mesh_path_lookup(sdata, preq_node->dst); if (!mpath) goto enddiscovery; spin_lock_bh(&mpath->state_lock); if (mpath->flags & (MESH_PATH_DELETED | MESH_PATH_FIXED)) { spin_unlock_bh(&mpath->state_lock); goto enddiscovery; } mpath->flags &= ~MESH_PATH_REQ_QUEUED; if (preq_node->flags & PREQ_Q_F_START) { if (mpath->flags & MESH_PATH_RESOLVING) { spin_unlock_bh(&mpath->state_lock); goto enddiscovery; } else { mpath->flags &= ~MESH_PATH_RESOLVED; mpath->flags |= MESH_PATH_RESOLVING; mpath->discovery_retries = 0; mpath->discovery_timeout = disc_timeout_jiff(sdata); } } else if (!(mpath->flags & MESH_PATH_RESOLVING) || mpath->flags & MESH_PATH_RESOLVED) { mpath->flags &= ~MESH_PATH_RESOLVING; spin_unlock_bh(&mpath->state_lock); goto enddiscovery; } ifmsh->last_preq = jiffies; if (time_after(jiffies, ifmsh->last_sn_update + net_traversal_jiffies(sdata)) || time_before(jiffies, ifmsh->last_sn_update)) { ++ifmsh->sn; sdata->u.mesh.last_sn_update = jiffies; } lifetime = default_lifetime(sdata); ttl = sdata->u.mesh.mshcfg.element_ttl; if (ttl == 0) { sdata->u.mesh.mshstats.dropped_frames_ttl++; spin_unlock_bh(&mpath->state_lock); goto enddiscovery; } if (preq_node->flags & PREQ_Q_F_REFRESH) target_flags |= IEEE80211_PREQ_TO_FLAG; else target_flags &= ~IEEE80211_PREQ_TO_FLAG; spin_unlock_bh(&mpath->state_lock); da = (mpath->is_root) ? mpath->rann_snd_addr : broadcast_addr; mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->vif.addr, ifmsh->sn, target_flags, mpath->dst, mpath->sn, da, 0, ttl, lifetime, 0, ifmsh->preq_id++, sdata); spin_lock_bh(&mpath->state_lock); if (!(mpath->flags & MESH_PATH_DELETED)) mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout); spin_unlock_bh(&mpath->state_lock); enddiscovery: rcu_read_unlock(); kfree(preq_node); } /** * mesh_nexthop_resolve - lookup next hop; conditionally start path discovery * * @skb: 802.11 frame to be sent * @sdata: network subif the frame will be sent through * * Lookup next hop for given skb and start path discovery if no * forwarding information is found. * * Returns: 0 if the next hop was found and -ENOENT if the frame was queued. * skb is freeed here if no mpath could be allocated. */ int mesh_nexthop_resolve(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb) { struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); struct mesh_path *mpath; struct sk_buff *skb_to_free = NULL; u8 *target_addr = hdr->addr3; /* Nulls are only sent to peers for PS and should be pre-addressed */ if (ieee80211_is_qos_nullfunc(hdr->frame_control)) return 0; /* Allow injected packets to bypass mesh routing */ if (info->control.flags & IEEE80211_TX_CTRL_SKIP_MPATH_LOOKUP) return 0; if (!mesh_nexthop_lookup(sdata, skb)) return 0; /* no nexthop found, start resolving */ mpath = mesh_path_lookup(sdata, target_addr); if (!mpath) { mpath = mesh_path_add(sdata, target_addr); if (IS_ERR(mpath)) { mesh_path_discard_frame(sdata, skb); return PTR_ERR(mpath); } } if (!(mpath->flags & MESH_PATH_RESOLVING) && mesh_path_sel_is_hwmp(sdata)) mesh_queue_preq(mpath, PREQ_Q_F_START); if (skb_queue_len(&mpath->frame_queue) >= MESH_FRAME_QUEUE_LEN) skb_to_free = skb_dequeue(&mpath->frame_queue); info->control.flags |= IEEE80211_TX_INTCFL_NEED_TXPROCESSING; ieee80211_set_qos_hdr(sdata, skb); skb_queue_tail(&mpath->frame_queue, skb); if (skb_to_free) mesh_path_discard_frame(sdata, skb_to_free); return -ENOENT; } /** * mesh_nexthop_lookup_nolearn - try to set next hop without path discovery * @skb: 802.11 frame to be sent * @sdata: network subif the frame will be sent through * * Check if the meshDA (addr3) of a unicast frame is a direct neighbor. * And if so, set the RA (addr1) to it to transmit to this node directly, * avoiding PREQ/PREP path discovery. * * Returns: 0 if the next hop was found and -ENOENT otherwise. */ static int mesh_nexthop_lookup_nolearn(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb) { struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data; struct sta_info *sta; if (is_multicast_ether_addr(hdr->addr1)) return -ENOENT; rcu_read_lock(); sta = sta_info_get(sdata, hdr->addr3); if (!sta || sta->mesh->plink_state != NL80211_PLINK_ESTAB) { rcu_read_unlock(); return -ENOENT; } rcu_read_unlock(); memcpy(hdr->addr1, hdr->addr3, ETH_ALEN); memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN); return 0; } /** * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame. Calling * this function is considered "using" the associated mpath, so preempt a path * refresh if this mpath expires soon. * * @skb: 802.11 frame to be sent * @sdata: network subif the frame will be sent through * * Returns: 0 if the next hop was found. Nonzero otherwise. */ int mesh_nexthop_lookup(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb) { struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh; struct mesh_path *mpath; struct sta_info *next_hop; struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; u8 *target_addr = hdr->addr3; if (ifmsh->mshcfg.dot11MeshNolearn && !mesh_nexthop_lookup_nolearn(sdata, skb)) return 0; mpath = mesh_path_lookup(sdata, target_addr); if (!mpath || !(mpath->flags & MESH_PATH_ACTIVE)) return -ENOENT; if (time_after(jiffies, mpath->exp_time - msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) && ether_addr_equal(sdata->vif.addr, hdr->addr4) && !(mpath->flags & MESH_PATH_RESOLVING) && !(mpath->flags & MESH_PATH_FIXED)) mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH); next_hop = rcu_dereference(mpath->next_hop); if (next_hop) { memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN); memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN); ieee80211_mps_set_frame_flags(sdata, next_hop, hdr); return 0; } return -ENOENT; } void mesh_path_timer(struct timer_list *t) { struct mesh_path *mpath = from_timer(mpath, t, timer); struct ieee80211_sub_if_data *sdata = mpath->sdata; int ret; if (sdata->local->quiescing) return; spin_lock_bh(&mpath->state_lock); if (mpath->flags & MESH_PATH_RESOLVED || (!(mpath->flags & MESH_PATH_RESOLVING))) { mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED); spin_unlock_bh(&mpath->state_lock); } else if (mpath->discovery_retries < max_preq_retries(sdata)) { ++mpath->discovery_retries; mpath->discovery_timeout *= 2; mpath->flags &= ~MESH_PATH_REQ_QUEUED; spin_unlock_bh(&mpath->state_lock); mesh_queue_preq(mpath, 0); } else { mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED | MESH_PATH_REQ_QUEUED); mpath->exp_time = jiffies; spin_unlock_bh(&mpath->state_lock); if (!mpath->is_gate && mesh_gate_num(sdata) > 0) { ret = mesh_path_send_to_gates(mpath); if (ret) mhwmp_dbg(sdata, "no gate was reachable\n"); } else mesh_path_flush_pending(mpath); } } void mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata) { struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh; u32 interval = ifmsh->mshcfg.dot11MeshHWMPRannInterval; u8 flags, target_flags = 0; flags = (ifmsh->mshcfg.dot11MeshGateAnnouncementProtocol) ? RANN_FLAG_IS_GATE : 0; switch (ifmsh->mshcfg.dot11MeshHWMPRootMode) { case IEEE80211_PROACTIVE_RANN: mesh_path_sel_frame_tx(MPATH_RANN, flags, sdata->vif.addr, ++ifmsh->sn, 0, NULL, 0, broadcast_addr, 0, ifmsh->mshcfg.element_ttl, interval, 0, 0, sdata); break; case IEEE80211_PROACTIVE_PREQ_WITH_PREP: flags |= IEEE80211_PREQ_PROACTIVE_PREP_FLAG; fallthrough; case IEEE80211_PROACTIVE_PREQ_NO_PREP: interval = ifmsh->mshcfg.dot11MeshHWMPactivePathToRootTimeout; target_flags |= IEEE80211_PREQ_TO_FLAG | IEEE80211_PREQ_USN_FLAG; mesh_path_sel_frame_tx(MPATH_PREQ, flags, sdata->vif.addr, ++ifmsh->sn, target_flags, (u8 *) broadcast_addr, 0, broadcast_addr, 0, ifmsh->mshcfg.element_ttl, interval, 0, ifmsh->preq_id++, sdata); break; default: mhwmp_dbg(sdata, "Proactive mechanism not supported\n"); return; } }