From 806c84ac8e8f60eaec22772b627f85eb5ac13544 Mon Sep 17 00:00:00 2001
From: Gioacchino Mazzurco <gio@polymathes.cc>
Date: Mon, 6 May 2024 13:53:48 +0200
Subject: [PATCH 1/3] Implement APuP Access Point Micro Peering

Access Point Micro Peering is a simpler and hopefully more useful successor to
Ad Hoc, Wireless Distribution System, 802.11s mesh mode, Multi-AP and EasyMesh.
When enabled almost plain APs communicate between them via 4-address mode,
like in WDS but all of them are AP, so they can eventually communicate also with
plain stations and more AP nodes in sight, without more trickery.
APuP has low hardware requirements, just AP mode support + 4-address mode, and
no more unnecessary complications, like hardcoded bridging or routing algorithm
in WiFi stack.
For each AP in sight an interface is created, and then it can be used as
convenient in each case, bridging, routing etc.
Those interfaces could be simply bridged in a trivial topology (which happens
automatically if wds_bridge is not an empty string), or feeded to a
routing daemon.

Signed-off-by: Gioacchino Mazzurco <gio@polymathes.cc>
Reviewed-by: Hauke Mehrtens <hauke@hauke-m.de>
Reviewed-by: Moritz Warning <moritzwarning@web.de>
Hotfix-by: Sebastian Gottschall https://github.com/mirror/dd-wrt/commit/0c3001a69e8d8300569e416de856c96e903ad130
---
 hostapd/Makefile             |   5 ++
 hostapd/config_file.c        |   9 +++
 src/ap/ap_config.h           |  29 +++++++
 src/ap/ap_drv_ops.c          |  28 ++++++-
 src/ap/ap_drv_ops.h          |   3 +
 src/ap/apup.c                | 152 +++++++++++++++++++++++++++++++++++
 src/ap/apup.h                |  24 ++++++
 src/ap/ieee802_11.c          |  14 +++-
 src/ap/ieee802_11.h          |   2 +
 src/drivers/driver.h         |   2 +-
 src/drivers/driver_nl80211.c |  14 +---
 11 files changed, 265 insertions(+), 17 deletions(-)
 create mode 100644 src/ap/apup.c
 create mode 100644 src/ap/apup.h

--- a/hostapd/Makefile
+++ b/hostapd/Makefile
@@ -1429,6 +1429,11 @@ ifdef CONFIG_NO_TKIP
 CFLAGS += -DCONFIG_NO_TKIP
 endif
 
+ifdef CONFIG_APUP
+CFLAGS += -DCONFIG_APUP
+OBJS += ../src/ap/apup.o
+endif
+
 $(DESTDIR)$(BINDIR)/%: %
 	install -D $(<) $(@)
 
--- a/hostapd/config_file.c
+++ b/hostapd/config_file.c
@@ -4976,6 +4976,15 @@ static int hostapd_config_fill(struct ho
 		bss->mld_indicate_disabled = atoi(pos);
 #endif /* CONFIG_TESTING_OPTIONS */
 #endif /* CONFIG_IEEE80211BE */
+#ifdef CONFIG_APUP
+	} else if (os_strcmp(buf, "apup") == 0) {
+		bss->apup = !!atoi(pos);
+		if (bss->apup)
+			bss->wds_sta = 1;
+	} else if (os_strcmp(buf, "apup_peer_ifname_prefix") == 0) {
+		os_strlcpy(bss->apup_peer_ifname_prefix,
+		           pos, sizeof(bss->apup_peer_ifname_prefix));
+#endif // def CONFIG_APUP
 	} else {
 		wpa_printf(MSG_ERROR,
 			   "Line %d: unknown configuration item '%s'",
--- a/src/ap/ap_config.h
+++ b/src/ap/ap_config.h
@@ -984,6 +984,35 @@ struct hostapd_bss_config {
 	int mbssid_index;
 
 	bool spp_amsdu;
+
+#ifdef CONFIG_APUP
+	/**
+	 * Access Point Micro Peering
+	 * A simpler and more useful successor to Ad Hoc,
+	 * Wireless Distribution System, 802.11s mesh mode, Multi-AP and EasyMesh.
+	 *
+	 * Almost plain APs communicate between them via 4-address mode, like in WDS
+	 * but all of them are AP, so they can eventually communicate also with
+	 * plain stations and more AP nodes in sight.
+	 * Low hardware requirements, just AP mode support + 4-address mode, and no
+	 * more unnecessary complications, like hardcoded bridging or routing
+	 * algorithm in WiFi stack.
+	 * For each AP in sight an interface is created, and then it can be used as
+	 * convenient in each case, bridging, routing etc.
+	 */
+	bool apup;
+
+	/**
+	 * In 4-address mode each peer AP in sight is associated to its own
+	 * interface so we have more flexibility in "user-space".
+	 * Those interfaces could be simply bridged in a trivial topology (which
+	 * happens automatically if wds_bridge is not an empty string), or feeded to
+	 * a routing daemon.
+	 *
+	 * If not defined interface names are generated following the WDS convention.
+	 */
+	char apup_peer_ifname_prefix[IFNAMSIZ + 1];
+#endif /* CONFIG_APUP */
 };
 
 /**
--- a/src/ap/ap_drv_ops.c
+++ b/src/ap/ap_drv_ops.c
@@ -385,13 +385,39 @@ int hostapd_set_wds_sta(struct hostapd_d
 			const u8 *addr, int aid, int val)
 {
 	const char *bridge = NULL;
+	char ifName[IFNAMSIZ + 1];
+
+	int mRet = 0;
 
 	if (hapd->driver == NULL || hapd->driver->set_wds_sta == NULL)
 		return -1;
+
+#ifdef CONFIG_APUP
+	if (hapd->conf->apup && hapd->conf->apup_peer_ifname_prefix[0]) {
+		mRet = os_snprintf(
+		            ifName, sizeof(ifName), "%s%d",
+		            hapd->conf->apup_peer_ifname_prefix, aid);
+	}
+	else
+#endif // def CONFIG_APUP
+		mRet = os_snprintf(
+		            ifName, sizeof(ifName), "%s.sta%d",
+		            hapd->conf->iface, aid);
+
+	if (mRet >= (int) sizeof(ifName))
+		wpa_printf(MSG_WARNING,
+		           "nl80211: WDS interface name was truncated");
+	else if (mRet < 0)
+		return mRet;
+
+	// Pass back to the caller the resulting interface name
+	if (ifname_wds)
+		os_strlcpy(ifname_wds, ifName, IFNAMSIZ + 1);
+
 	if (hapd->conf->wds_bridge[0])
 		bridge = hapd->conf->wds_bridge;
 	return hapd->driver->set_wds_sta(hapd->drv_priv, addr, aid, val,
-					 bridge, ifname_wds);
+					 bridge, ifName);
 }
 
 
--- a/src/ap/ap_drv_ops.h
+++ b/src/ap/ap_drv_ops.h
@@ -35,6 +35,9 @@ int hostapd_set_drv_ieee8021x(struct hos
 			      int enabled);
 int hostapd_vlan_if_add(struct hostapd_data *hapd, const char *ifname);
 int hostapd_vlan_if_remove(struct hostapd_data *hapd, const char *ifname);
+
+/** @param val as per nl80211 driver implementation, 1 means add 0 means remove
+ */
 int hostapd_set_wds_sta(struct hostapd_data *hapd, char *ifname_wds,
 			const u8 *addr, int aid, int val);
 int hostapd_sta_add(struct hostapd_data *hapd,
--- /dev/null
+++ b/src/ap/apup.c
@@ -0,0 +1,169 @@
+/*
+ * hostapd / APuP Access Point Micro Peering
+ *
+ * Copyright (C) 2023-2024  Gioacchino Mazzurco <gio@polymathes.cc>
+ *
+ * This software may be distributed under the terms of the BSD license.
+ * See README for more details.
+ */
+
+/* Be extremely careful altering include order, move just one in the wrong place
+ * and you will start getting a bunch of error of undefined bool, size_t etc. */
+
+#include "utils/includes.h"
+#include "utils/common.h"
+#include "utils/os.h"
+
+#include "apup.h"
+
+#include "drivers/driver.h"
+#include "wpa_auth.h"
+#include "ap_mlme.h"
+#include "ieee802_11.h"
+#include "ap_drv_ops.h"
+#include "sta_info.h"
+
+#ifdef UBUS_SUPPORT
+#	include "ubus.h"
+#endif
+
+#ifdef UCODE_SUPPORT
+#	include "ucode.h"
+#endif
+
+void apup_process_beacon(struct hostapd_data *hapd,
+              const struct ieee80211_mgmt *mgmt, size_t len,
+              const struct ieee802_11_elems *elems )
+{
+	if (!os_memcmp(hapd->own_addr, mgmt->bssid, ETH_ALEN))
+	{
+		wpa_printf(MSG_WARNING,
+		           "apup_process_beacon(...) own beacon elems.ssid %.*s",
+		           (int) elems->ssid_len, elems->ssid);
+		return;
+	}
+
+	if (elems->ssid_len != hapd->conf->ssid.ssid_len ||
+	        os_memcmp(elems->ssid, hapd->conf->ssid.ssid, elems->ssid_len))
+		return;
+
+	struct sta_info* sta_ret = ap_get_sta(hapd, mgmt->bssid);
+	if (sta_ret)
+		return;
+
+	sta_ret = ap_sta_add(hapd, mgmt->bssid);
+
+	/* TODO: this has been added just to making compiler happy after breaking
+	 * changes introduced in 11a607d12 and 7855b6d60 to support
+	 * IEEE80211BE Multi Link Operation. Look at these commits with more time and
+	 * understand what could be a proper implementation in this context too
+	 */
+	const u8 *mld_link_addr = NULL;
+	bool mld_link_sta = false;
+	u16 eml_cap = 0;
+
+	/* First add the station without more information */
+	int aRet = hostapd_sta_add(
+	            hapd, mgmt->bssid, sta_ret->aid, 0,
+	            NULL, 0, 0, NULL, NULL, NULL, 0, NULL, 0, NULL,
+	            sta_ret->flags, 0, 0, 0,
+	            0, // 0 add, 1 set
+	            mld_link_addr, mld_link_sta, eml_cap);
+
+	sta_ret->flags |= WLAN_STA_AUTH;
+	wpa_auth_sm_event(sta_ret->wpa_sm, WPA_AUTH);
+
+	/* TODO: Investigate if supporting WPA or other encryption method is
+	 * possible */
+	sta_ret->auth_alg = WLAN_AUTH_OPEN;
+	mlme_authenticate_indication(hapd, sta_ret);
+
+	sta_ret->capability = le_to_host16(mgmt->u.beacon.capab_info);
+
+	if (sta_ret->capability & WLAN_CAPABILITY_SHORT_PREAMBLE)
+		sta_ret->flags |= WLAN_STA_SHORT_PREAMBLE;
+	else
+		sta_ret->flags &= ~WLAN_STA_SHORT_PREAMBLE;
+
+	hostapd_copy_supp_rates(hapd, sta_ret, elems);
+
+	/* Whithout this flag copy_sta_[v]ht_capab will disable [V]HT
+	 * capabilities even if available */
+	if (elems->ht_capabilities || elems->vht_capabilities)
+		sta_ret->flags |= WLAN_STA_WMM;
+
+	copy_sta_ht_capab(hapd, sta_ret, elems->ht_capabilities);
+#ifdef CONFIG_IEEE80211AC
+	copy_sta_vht_capab(hapd, sta_ret, elems->vht_capabilities);
+	copy_sta_vht_oper(hapd, sta_ret, elems->vht_operation);
+	copy_sta_vendor_vht(hapd, sta_ret, elems->vendor_vht, elems->vendor_vht_len);
+#endif // def CONFIG_IEEE80211AC
+#ifdef CONFIG_IEEE80211AX
+	copy_sta_he_capab(hapd, sta_ret, IEEE80211_MODE_AP,
+	                  elems->he_capabilities, elems->he_capabilities_len);
+	copy_sta_he_6ghz_capab(hapd, sta_ret,  elems->he_6ghz_band_cap);
+#endif // def CONFIG_IEEE80211AX
+#ifdef CONFIG_IEEE80211BE
+	copy_sta_eht_capab(hapd, sta_ret,
+	                   IEEE80211_MODE_AP, // TODO: Make sure is the right value
+	                   elems->he_capabilities, elems->he_capabilities_len,
+	                   elems->eht_capabilities, elems->eht_capabilities_len);
+#endif //def CONFIG_IEEE80211BE
+
+	update_ht_state(hapd, sta_ret);
+
+	if (hostapd_get_aid(hapd, sta_ret) < 0)
+	{
+		wpa_printf(MSG_INFO, "apup_process_beacon(...) No room for more AIDs");
+		return;
+	}
+
+	sta_ret->flags |= WLAN_STA_ASSOC_REQ_OK;
+
+	/* Make sure that the previously registered inactivity timer will not
+	 * remove the STA immediately. */
+	sta_ret->timeout_next = STA_NULLFUNC;
+
+	sta_ret->flags |= WLAN_STA_AUTH | WLAN_STA_ASSOC;
+
+	/* Then set the paramethers */
+	int sRet = hostapd_sta_add(
+	            hapd, mgmt->bssid, sta_ret->aid,
+	            sta_ret->capability,
+	            sta_ret->supported_rates, sta_ret->supported_rates_len,
+	            0, // u16 listen_interval TODO ?
+	            sta_ret->ht_capabilities,
+	            sta_ret->vht_capabilities,
+	            sta_ret->he_capab, sta_ret->he_capab_len,
+	            sta_ret->eht_capab, sta_ret->eht_capab_len,
+	            sta_ret->he_6ghz_capab,
+	            sta_ret->flags,
+	            0, // u8 qosinfo
+	            sta_ret->vht_opmode,
+	            0, // int supp_p2p_ps
+	            1, // 0 add, 1 set
+	            mld_link_addr, mld_link_sta, eml_cap);
+
+	ap_sta_set_authorized(hapd, sta_ret, 1);
+	hostapd_set_sta_flags(hapd, sta_ret);
+
+	char mIfname[IFNAMSIZ + 1];
+	os_memset(mIfname, 0, IFNAMSIZ + 1);
+
+	// last param 1 means add 0 means remove
+	int mRet = hostapd_set_wds_sta(
+	            hapd, mIfname, mgmt->bssid, sta_ret->aid, 1);
+
+	wpa_printf(MSG_INFO,
+	           "apup_process_beacon(...) Added APuP peer at %s with flags: %d,"
+	           " capabilities %d",
+	           mIfname, sta_ret->flags, sta_ret->capability);
+
+#ifdef UBUS_SUPPORT
+	hostapd_ubus_notify_apup_newpeer(hapd, mgmt->bssid, mIfname);
+#endif
+
+#ifdef UCODE_SUPPORT
+	hostapd_ucode_apup_newpeer(hapd, mIfname);
+#endif
+}
--- /dev/null
+++ b/src/ap/apup.h
@@ -0,0 +1,24 @@
+/*
+ * hostapd / APuP Access Point Micro Peering
+ *
+ * Copyright (C) 2023-2024  Gioacchino Mazzurco <gio@polymathes.cc>
+ *
+ * This software may be distributed under the terms of the BSD license.
+ * See README for more details.
+ */
+
+/* Be extremely careful altering include order, move just one in the wrong place
+ * and you will start getting a bunch of error of undefined bool, size_t etc. */
+
+#include "utils/includes.h"
+#include "utils/common.h"
+
+#include "hostapd.h"
+#include "common/ieee802_11_defs.h"
+
+/** When beacons from other Access Point are received, if the SSID is matching
+ * add them as APuP peers (aka WDS STA to our own AP) the same happens on the
+ * peer when receiving our beacons */
+void apup_process_beacon(struct hostapd_data *hapd,
+              const struct ieee80211_mgmt *mgmt, size_t len,
+              const struct ieee802_11_elems *elems );
--- a/src/ap/ieee802_11.c
+++ b/src/ap/ieee802_11.c
@@ -60,6 +60,9 @@
 #include "nan_usd_ap.h"
 #include "pasn/pasn_common.h"
 
+#ifdef CONFIG_APUP
+#	include "apup.h"
+#endif // def CONFIG_APUP
 
 #ifdef CONFIG_FILS
 static struct wpabuf *
@@ -3880,8 +3883,8 @@ static u16 check_multi_ap(struct hostapd
 }
 
 
-static u16 copy_supp_rates(struct hostapd_data *hapd, struct sta_info *sta,
-			   struct ieee802_11_elems *elems)
+u16 hostapd_copy_supp_rates(struct hostapd_data *hapd, struct sta_info *sta,
+			   const struct ieee802_11_elems *elems)
 {
 	/* Supported rates not used in IEEE 802.11ad/DMG */
 	if (hapd->iface->current_mode &&
@@ -4326,7 +4329,7 @@ static int __check_assoc_ies(struct host
 			       elems->ext_capab_len);
 	if (resp != WLAN_STATUS_SUCCESS)
 		return resp;
-	resp = copy_supp_rates(hapd, sta, elems);
+	resp = hostapd_copy_supp_rates(hapd, sta, elems);
 	if (resp != WLAN_STATUS_SUCCESS)
 		return resp;
 
@@ -6422,6 +6425,11 @@ static void handle_beacon(struct hostapd
 				      0);
 
 	ap_list_process_beacon(hapd->iface, mgmt, &elems, fi);
+
+#ifdef CONFIG_APUP
+	if (hapd->conf->apup)
+		apup_process_beacon(hapd, mgmt, len, &elems);
+#endif // def CONFIG_APUP
 }
 
 
--- a/src/ap/ieee802_11.h
+++ b/src/ap/ieee802_11.h
@@ -145,6 +145,8 @@ int hostapd_process_ml_assoc_req_addr(st
 				      const u8 *basic_mle, size_t basic_mle_len,
 				      u8 *mld_addr);
 int hostapd_get_aid(struct hostapd_data *hapd, struct sta_info *sta);
+u16 hostapd_copy_supp_rates(struct hostapd_data *hapd, struct sta_info *sta,
+		      const struct ieee802_11_elems *elems);
 u16 copy_sta_ht_capab(struct hostapd_data *hapd, struct sta_info *sta,
 		      const u8 *ht_capab);
 u16 copy_sta_vendor_vht(struct hostapd_data *hapd, struct sta_info *sta,
--- a/src/drivers/driver.h
+++ b/src/drivers/driver.h
@@ -4192,7 +4192,7 @@ struct wpa_driver_ops {
 	 * Returns: 0 on success, -1 on failure
 	 */
 	int (*set_wds_sta)(void *priv, const u8 *addr, int aid, int val,
-			   const char *bridge_ifname, char *ifname_wds);
+			   const char *bridge_ifname, const char *ifname_wds);
 
 	/**
 	 * send_action - Transmit an Action frame
--- a/src/drivers/driver_nl80211.c
+++ b/src/drivers/driver_nl80211.c
@@ -8706,25 +8706,15 @@ static int have_ifidx(struct wpa_driver_
 
 
 static int i802_set_wds_sta(void *priv, const u8 *addr, int aid, int val,
-			    const char *bridge_ifname, char *ifname_wds)
+			    const char *bridge_ifname, const char *ifname_wds)
 {
 	struct i802_bss *bss = priv;
 	struct wpa_driver_nl80211_data *drv = bss->drv;
-	char name[IFNAMSIZ + 1];
+	const char *name = ifname_wds; // Kept to reduce changes to the minimum
 	union wpa_event_data event;
 	bool add_br = false;
 	int ret;
 
-	ret = os_snprintf(name, sizeof(name), "%s.sta%d", bss->ifname, aid);
-	if (ret >= (int) sizeof(name))
-		wpa_printf(MSG_WARNING,
-			   "nl80211: WDS interface name was truncated");
-	else if (ret < 0)
-		return ret;
-
-	if (ifname_wds)
-		os_strlcpy(ifname_wds, name, IFNAMSIZ + 1);
-
 	wpa_printf(MSG_DEBUG, "nl80211: Set WDS STA addr=" MACSTR
 		   " aid=%d val=%d name=%s", MAC2STR(addr), aid, val, name);
 	if (val) {
