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      1 /******************************************************************************
      2  *
      3  *  Copyright (C) 2009-2012 Broadcom Corporation
      4  *
      5  *  Licensed under the Apache License, Version 2.0 (the "License");
      6  *  you may not use this file except in compliance with the License.
      7  *  You may obtain a copy of the License at:
      8  *
      9  *  http://www.apache.org/licenses/LICENSE-2.0
     10  *
     11  *  Unless required by applicable law or agreed to in writing, software
     12  *  distributed under the License is distributed on an "AS IS" BASIS,
     13  *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     14  *  See the License for the specific language governing permissions and
     15  *  limitations under the License.
     16  *
     17  ******************************************************************************/
     18 
     19 /************************************************************************************
     20  *
     21  *  Filename:      btif_pan.c
     22  *
     23  *  Description:   PAN Profile Bluetooth Interface
     24  *
     25  *
     26  ***********************************************************************************/
     27 
     28 #define LOG_TAG "bt_btif_pan"
     29 
     30 #include <assert.h>
     31 #include <ctype.h>
     32 #include <errno.h>
     33 #include <fcntl.h>
     34 #include <linux/if_ether.h>
     35 #include <linux/if_tun.h>
     36 #include <linux/sockios.h>
     37 #include <net/if.h>
     38 #include <netdb.h>
     39 #include <netinet/in.h>
     40 #include <signal.h>
     41 #include <stdio.h>
     42 #include <string.h>
     43 #include <string.h>
     44 #include <sys/ioctl.h>
     45 #include <sys/poll.h>
     46 #include <sys/prctl.h>
     47 #include <sys/select.h>
     48 #include <sys/socket.h>
     49 #include <sys/wait.h>
     50 #include <unistd.h>
     51 
     52 #include <hardware/bluetooth.h>
     53 #include <hardware/bt_pan.h>
     54 
     55 #include "bta_api.h"
     56 #include "bta_pan_api.h"
     57 #include "btcore/include/bdaddr.h"
     58 #include "btif_common.h"
     59 #include "btif_pan_internal.h"
     60 #include "btif_sock_thread.h"
     61 #include "btif_sock_util.h"
     62 #include "btif_util.h"
     63 #include "btm_api.h"
     64 #include "device/include/controller.h"
     65 #include "bt_common.h"
     66 #include "osi/include/log.h"
     67 #include "osi/include/osi.h"
     68 
     69 #define FORWARD_IGNORE        1
     70 #define FORWARD_SUCCESS       0
     71 #define FORWARD_FAILURE     (-1)
     72 #define FORWARD_CONGEST     (-2)
     73 //#define PANU_DISABLED TRUE
     74 
     75 #if (PAN_NAP_DISABLED == TRUE) && (PANU_DISABLED == TRUE)
     76 #define BTPAN_LOCAL_ROLE BTPAN_ROLE_NONE
     77 #elif PAN_NAP_DISABLED == TRUE
     78 #define BTPAN_LOCAL_ROLE BTPAN_ROLE_PANU
     79 #elif PANU_DISABLED == TRUE
     80 #define BTPAN_LOCAL_ROLE BTPAN_ROLE_PANNAP
     81 #else
     82 #define BTPAN_LOCAL_ROLE (BTPAN_ROLE_PANU | BTPAN_ROLE_PANNAP)
     83 #endif
     84 
     85 #define asrt(s) if (!(s)) BTIF_TRACE_ERROR("btif_pan: ## %s assert %s failed at line:%d ##",__FUNCTION__, #s, __LINE__)
     86 
     87 #define MIN(x, y) (((x) < (y)) ? (x) : (y))
     88 
     89 btpan_cb_t btpan_cb;
     90 
     91 static bool jni_initialized;
     92 static bool stack_initialized;
     93 
     94 static bt_status_t btpan_jni_init(const btpan_callbacks_t* callbacks);
     95 static void btpan_jni_cleanup();
     96 static bt_status_t btpan_connect(const bt_bdaddr_t *bd_addr, int local_role, int remote_role);
     97 static bt_status_t btpan_disconnect(const bt_bdaddr_t *bd_addr);
     98 static bt_status_t btpan_enable(int local_role);
     99 static int btpan_get_local_role(void);
    100 
    101 static void btpan_tap_fd_signaled(int fd, int type, int flags, uint32_t user_id);
    102 static void btpan_cleanup_conn(btpan_conn_t* conn);
    103 static void bta_pan_callback(tBTA_PAN_EVT event, tBTA_PAN *p_data);
    104 static void btu_exec_tap_fd_read(void *p_param);
    105 
    106 static btpan_interface_t pan_if = {
    107     sizeof(pan_if),
    108     btpan_jni_init,
    109     btpan_enable,
    110     btpan_get_local_role,
    111     btpan_connect,
    112     btpan_disconnect,
    113     btpan_jni_cleanup
    114 };
    115 
    116 btpan_interface_t *btif_pan_get_interface()
    117 {
    118     return &pan_if;
    119 }
    120 
    121 /*******************************************************************************
    122  **
    123  ** Function        btif_pan_init
    124  **
    125  ** Description     initializes the pan interface
    126  **
    127  ** Returns         bt_status_t
    128  **
    129  *******************************************************************************/
    130 void btif_pan_init()
    131 {
    132     BTIF_TRACE_DEBUG("jni_initialized = %d, btpan_cb.enabled:%d", jni_initialized, btpan_cb.enabled);
    133     stack_initialized = true;
    134 
    135     if (jni_initialized && !btpan_cb.enabled)
    136     {
    137         BTIF_TRACE_DEBUG("Enabling PAN....");
    138         memset(&btpan_cb, 0, sizeof(btpan_cb));
    139         btpan_cb.tap_fd = INVALID_FD;
    140         btpan_cb.flow = 1;
    141         for (int i = 0; i < MAX_PAN_CONNS; i++)
    142             btpan_cleanup_conn(&btpan_cb.conns[i]);
    143         BTA_PanEnable(bta_pan_callback);
    144         btpan_cb.enabled = 1;
    145         btpan_enable(BTPAN_LOCAL_ROLE);
    146     }
    147 }
    148 
    149 static void pan_disable()
    150 {
    151     if (btpan_cb.enabled)
    152     {
    153         btpan_cb.enabled = 0;
    154         BTA_PanDisable();
    155         if (btpan_cb.tap_fd != INVALID_FD)
    156         {
    157             btpan_tap_close(btpan_cb.tap_fd);
    158             btpan_cb.tap_fd = INVALID_FD;
    159         }
    160     }
    161 }
    162 
    163 void btif_pan_cleanup()
    164 {
    165     if (!stack_initialized)
    166         return;
    167 
    168     // Bluetooth is shuting down, invalidate all BTA PAN handles
    169     for (int i = 0; i < MAX_PAN_CONNS; i++)
    170         btpan_cleanup_conn(&btpan_cb.conns[i]);
    171 
    172     pan_disable();
    173     stack_initialized = false;
    174 }
    175 
    176 static btpan_callbacks_t callback;
    177 static bt_status_t btpan_jni_init(const btpan_callbacks_t* callbacks)
    178 {
    179     BTIF_TRACE_DEBUG("stack_initialized = %d, btpan_cb.enabled:%d", stack_initialized, btpan_cb.enabled);
    180     callback = *callbacks;
    181     jni_initialized = TRUE;
    182     if (stack_initialized && !btpan_cb.enabled)
    183         btif_pan_init();
    184     return BT_STATUS_SUCCESS;
    185 }
    186 
    187 static void btpan_jni_cleanup()
    188 {
    189     pan_disable();
    190     jni_initialized = false;
    191 }
    192 
    193 static inline int bta_role_to_btpan(int bta_pan_role)
    194 {
    195     int btpan_role = 0;
    196     BTIF_TRACE_DEBUG("bta_pan_role:0x%x", bta_pan_role);
    197     if (bta_pan_role & PAN_ROLE_NAP_SERVER)
    198         btpan_role |= BTPAN_ROLE_PANNAP;
    199     if (bta_pan_role & PAN_ROLE_CLIENT)
    200         btpan_role |= BTPAN_ROLE_PANU;
    201     return btpan_role;
    202 }
    203 
    204 static inline int btpan_role_to_bta(int btpan_role)
    205 {
    206     int bta_pan_role = PAN_ROLE_INACTIVE;
    207     BTIF_TRACE_DEBUG("btpan_role:0x%x", btpan_role);
    208     if (btpan_role & BTPAN_ROLE_PANNAP)
    209         bta_pan_role |= PAN_ROLE_NAP_SERVER;
    210     if (btpan_role & BTPAN_ROLE_PANU)
    211         bta_pan_role |= PAN_ROLE_CLIENT;
    212     return bta_pan_role;
    213 }
    214 
    215 static volatile int btpan_dev_local_role;
    216 #if BTA_PAN_INCLUDED == TRUE
    217 static tBTA_PAN_ROLE_INFO bta_panu_info = {PANU_SERVICE_NAME, 0, PAN_SECURITY};
    218 static tBTA_PAN_ROLE_INFO bta_pan_nap_info = {PAN_NAP_SERVICE_NAME, 1, PAN_SECURITY};
    219 #endif
    220 
    221 static bt_status_t btpan_enable(int local_role)
    222 {
    223 #if BTA_PAN_INCLUDED == TRUE
    224     BTIF_TRACE_DEBUG("%s - local_role: %d", __func__, local_role);
    225     int bta_pan_role = btpan_role_to_bta(local_role);
    226     BTA_PanSetRole(bta_pan_role, &bta_panu_info, NULL, &bta_pan_nap_info);
    227     btpan_dev_local_role = local_role;
    228     return BT_STATUS_SUCCESS;
    229 #else
    230     return BT_STATUS_FAIL;
    231 #endif
    232 }
    233 
    234 static int btpan_get_local_role()
    235 {
    236     BTIF_TRACE_DEBUG("btpan_dev_local_role:%d", btpan_dev_local_role);
    237     return btpan_dev_local_role;
    238 }
    239 
    240 static bt_status_t btpan_connect(const bt_bdaddr_t *bd_addr, int local_role, int remote_role)
    241 {
    242     BTIF_TRACE_DEBUG("local_role:%d, remote_role:%d", local_role, remote_role);
    243     int bta_local_role = btpan_role_to_bta(local_role);
    244     int bta_remote_role = btpan_role_to_bta(remote_role);
    245     btpan_new_conn(-1, bd_addr->address, bta_local_role, bta_remote_role);
    246     BTA_PanOpen((UINT8*)bd_addr->address, bta_local_role, bta_remote_role);
    247     return BT_STATUS_SUCCESS;
    248 }
    249 
    250 static void btif_in_pan_generic_evt(UINT16 event, char *p_param)
    251 {
    252     BTIF_TRACE_EVENT("%s: event=%d", __FUNCTION__, event);
    253     switch (event) {
    254         case BTIF_PAN_CB_DISCONNECTING:
    255         {
    256             bt_bdaddr_t *bd_addr = (bt_bdaddr_t*)p_param;
    257             btpan_conn_t* conn = btpan_find_conn_addr(bd_addr->address);
    258             int btpan_conn_local_role;
    259             int btpan_remote_role;
    260             asrt(conn != NULL);
    261             if (conn) {
    262                 btpan_conn_local_role = bta_role_to_btpan(conn->local_role);
    263                 btpan_remote_role = bta_role_to_btpan(conn->remote_role);
    264                 callback.connection_state_cb(BTPAN_STATE_DISCONNECTING, BT_STATUS_SUCCESS,
    265                         (const bt_bdaddr_t*)conn->peer, btpan_conn_local_role, btpan_remote_role);
    266             }
    267         } break;
    268         default:
    269         {
    270             BTIF_TRACE_WARNING("%s : Unknown event 0x%x", __FUNCTION__, event);
    271         }
    272         break;
    273     }
    274 }
    275 
    276 static bt_status_t btpan_disconnect(const bt_bdaddr_t *bd_addr)
    277 {
    278     btpan_conn_t* conn = btpan_find_conn_addr(bd_addr->address);
    279     if (conn && conn->handle >= 0)
    280     {
    281         /* Inform the application that the disconnect has been initiated successfully */
    282         btif_transfer_context(btif_in_pan_generic_evt, BTIF_PAN_CB_DISCONNECTING,
    283                               (char *)bd_addr, sizeof(bt_bdaddr_t), NULL);
    284         BTA_PanClose(conn->handle);
    285         return BT_STATUS_SUCCESS;
    286     }
    287     return BT_STATUS_FAIL;
    288 }
    289 
    290 static int pan_pth = -1;
    291 void create_tap_read_thread(int tap_fd)
    292 {
    293     if (pan_pth < 0)
    294         pan_pth = btsock_thread_create(btpan_tap_fd_signaled, NULL);
    295     if (pan_pth >= 0)
    296         btsock_thread_add_fd(pan_pth, tap_fd, 0, SOCK_THREAD_FD_RD, 0);
    297 }
    298 
    299 void destroy_tap_read_thread(void)
    300 {
    301     if (pan_pth >= 0)
    302     {
    303         btsock_thread_exit(pan_pth);
    304         pan_pth = -1;
    305     }
    306 }
    307 
    308 static int tap_if_up(const char *devname, const bt_bdaddr_t *addr)
    309 {
    310     struct ifreq ifr;
    311     int sk, err;
    312 
    313     sk = socket(AF_INET, SOCK_DGRAM, 0);
    314     if (sk < 0)
    315         return -1;
    316 
    317     //set mac addr
    318     memset(&ifr, 0, sizeof(ifr));
    319     strncpy(ifr.ifr_name, devname, IFNAMSIZ - 1);
    320     err = ioctl(sk, SIOCGIFHWADDR, &ifr);
    321     if (err < 0)
    322     {
    323         BTIF_TRACE_ERROR("Could not get network hardware for interface:%s, errno:%s", devname, strerror(errno));
    324         close(sk);
    325         return -1;
    326     }
    327 
    328     strncpy(ifr.ifr_name, devname, IFNAMSIZ - 1);
    329     memcpy(ifr.ifr_hwaddr.sa_data, addr->address, 6);
    330 
    331     /* The IEEE has specified that the most significant bit of the most significant byte is used to
    332      * determine a multicast address. If its a 1, that means multicast, 0 means unicast.
    333      * Kernel returns an error if we try to set a multicast address for the tun-tap ethernet interface.
    334      * Mask this bit to avoid any issue with auto generated address.
    335      */
    336     if (ifr.ifr_hwaddr.sa_data[0] & 0x01) {
    337         BTIF_TRACE_WARNING("Not a unicast MAC address, force multicast bit flipping");
    338         ifr.ifr_hwaddr.sa_data[0] &= ~0x01;
    339     }
    340 
    341     err = ioctl(sk, SIOCSIFHWADDR, (caddr_t)&ifr);
    342 
    343     if (err < 0) {
    344         BTIF_TRACE_ERROR("Could not set bt address for interface:%s, errno:%s", devname, strerror(errno));
    345         close(sk);
    346         return -1;
    347     }
    348 
    349     //bring it up
    350     memset(&ifr, 0, sizeof(ifr));
    351     strncpy(ifr.ifr_name, devname, IF_NAMESIZE - 1);
    352 
    353     ifr.ifr_flags |= IFF_UP;
    354     ifr.ifr_flags |= IFF_MULTICAST;
    355 
    356     err = ioctl(sk, SIOCSIFFLAGS, (caddr_t) &ifr);
    357 
    358 
    359     if (err < 0) {
    360         BTIF_TRACE_ERROR("Could not bring up network interface:%s, errno:%d", devname, errno);
    361         close(sk);
    362         return -1;
    363     }
    364     close(sk);
    365     BTIF_TRACE_DEBUG("network interface: %s is up", devname);
    366     return 0;
    367 }
    368 
    369 static int tap_if_down(const char *devname)
    370 {
    371     struct ifreq ifr;
    372     int sk;
    373 
    374     sk = socket(AF_INET, SOCK_DGRAM, 0);
    375     if (sk < 0)
    376         return -1;
    377 
    378     memset(&ifr, 0, sizeof(ifr));
    379     strncpy(ifr.ifr_name, devname, IF_NAMESIZE - 1);
    380 
    381     ifr.ifr_flags &= ~IFF_UP;
    382 
    383     ioctl(sk, SIOCSIFFLAGS, (caddr_t) &ifr);
    384 
    385     close(sk);
    386 
    387     return 0;
    388 }
    389 
    390 void btpan_set_flow_control(BOOLEAN enable) {
    391     if (btpan_cb.tap_fd == -1)
    392         return;
    393 
    394     btpan_cb.flow = enable;
    395     if (enable) {
    396         btsock_thread_add_fd(pan_pth, btpan_cb.tap_fd, 0, SOCK_THREAD_FD_RD, 0);
    397         bta_dmexecutecallback(btu_exec_tap_fd_read, INT_TO_PTR(btpan_cb.tap_fd));
    398     }
    399 }
    400 
    401 int btpan_tap_open()
    402 {
    403     struct ifreq ifr;
    404     int fd, err;
    405     const char *clonedev = "/dev/tun";
    406 
    407     /* open the clone device */
    408 
    409     if ((fd = open(clonedev, O_RDWR)) < 0)
    410     {
    411         BTIF_TRACE_DEBUG("could not open %s, err:%d", clonedev, errno);
    412         return fd;
    413     }
    414 
    415     memset(&ifr, 0, sizeof(ifr));
    416     ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
    417 
    418     strncpy(ifr.ifr_name, TAP_IF_NAME, IFNAMSIZ);
    419 
    420     /* try to create the device */
    421     if ((err = ioctl(fd, TUNSETIFF, (void *) &ifr)) < 0)
    422     {
    423         BTIF_TRACE_DEBUG("ioctl error:%d, errno:%s", err, strerror(errno));
    424         close(fd);
    425         return err;
    426     }
    427     if (tap_if_up(TAP_IF_NAME, controller_get_interface()->get_address()) == 0)
    428     {
    429         int flags = fcntl(fd, F_GETFL, 0);
    430         fcntl(fd, F_SETFL, flags | O_NONBLOCK);
    431         return fd;
    432     }
    433     BTIF_TRACE_ERROR("can not bring up tap interface:%s", TAP_IF_NAME);
    434     close(fd);
    435     return INVALID_FD;
    436 }
    437 
    438 int btpan_tap_send(int tap_fd, const BD_ADDR src, const BD_ADDR dst, UINT16 proto, const char* buf,
    439                     UINT16 len, BOOLEAN ext, BOOLEAN forward)
    440 {
    441     UNUSED(ext);
    442     UNUSED(forward);
    443     if (tap_fd != INVALID_FD)
    444     {
    445         tETH_HDR eth_hdr;
    446         memcpy(&eth_hdr.h_dest, dst, ETH_ADDR_LEN);
    447         memcpy(&eth_hdr.h_src, src, ETH_ADDR_LEN);
    448         eth_hdr.h_proto = htons(proto);
    449         char packet[TAP_MAX_PKT_WRITE_LEN + sizeof(tETH_HDR)];
    450         memcpy(packet, &eth_hdr, sizeof(tETH_HDR));
    451         if (len > TAP_MAX_PKT_WRITE_LEN)
    452         {
    453             LOG_ERROR(LOG_TAG, "btpan_tap_send eth packet size:%d is exceeded limit!", len);
    454             return -1;
    455         }
    456         memcpy(packet + sizeof(tETH_HDR), buf, len);
    457 
    458         /* Send data to network interface */
    459         ssize_t ret;
    460         OSI_NO_INTR(ret = write(tap_fd, packet, len + sizeof(tETH_HDR)));
    461         BTIF_TRACE_DEBUG("ret:%d", ret);
    462         return (int)ret;
    463     }
    464     return -1;
    465 
    466 }
    467 
    468 int btpan_tap_close(int fd)
    469 {
    470     if (tap_if_down(TAP_IF_NAME) == 0)
    471         close(fd);
    472     if (pan_pth >= 0)
    473         btsock_thread_wakeup(pan_pth);
    474     return 0;
    475 }
    476 
    477 btpan_conn_t * btpan_find_conn_handle(UINT16 handle)
    478 {
    479     for (int i = 0; i < MAX_PAN_CONNS; i++)
    480     {
    481         if (btpan_cb.conns[i].handle == handle)
    482             return &btpan_cb.conns[i];
    483     }
    484     return NULL;
    485 }
    486 
    487 btpan_conn_t* btpan_find_conn_addr(const BD_ADDR addr)
    488 {
    489     for (int i = 0; i < MAX_PAN_CONNS; i++)
    490     {
    491         if (memcmp(btpan_cb.conns[i].peer, addr, sizeof(BD_ADDR)) == 0)
    492             return &btpan_cb.conns[i];
    493     }
    494     return NULL;
    495 }
    496 
    497 static void btpan_open_conn(btpan_conn_t* conn, tBTA_PAN *p_data)
    498 {
    499     BTIF_TRACE_API("btpan_open_conn: local_role:%d, peer_role: %d,  handle:%d, conn: %p",
    500             p_data->open.local_role, p_data->open.peer_role, p_data->open.handle, conn);
    501 
    502     if (conn == NULL)
    503         conn = btpan_new_conn(p_data->open.handle, p_data->open.bd_addr, p_data->open.local_role,
    504                 p_data->open.peer_role);
    505     if (conn)
    506     {
    507         BTIF_TRACE_DEBUG("btpan_open_conn:tap_fd:%d, open_count:%d, "
    508                 "conn->handle:%d should = handle:%d, local_role:%d, remote_role:%d",
    509                 btpan_cb.tap_fd, btpan_cb.open_count, conn->handle, p_data->open.handle,
    510                 conn->local_role, conn->remote_role);
    511 
    512         btpan_cb.open_count++;
    513         conn->handle = p_data->open.handle;
    514         if (btpan_cb.tap_fd < 0)
    515         {
    516             btpan_cb.tap_fd = btpan_tap_open();
    517             if(btpan_cb.tap_fd >= 0)
    518                 create_tap_read_thread(btpan_cb.tap_fd);
    519         }
    520 
    521         if (btpan_cb.tap_fd >= 0)
    522         {
    523             btpan_cb.flow = 1;
    524             conn->state = PAN_STATE_OPEN;
    525         }
    526     }
    527 }
    528 
    529 static void btpan_close_conn(btpan_conn_t* conn)
    530 {
    531     BTIF_TRACE_API("btpan_close_conn: %p",conn);
    532 
    533     if (conn && conn->state == PAN_STATE_OPEN)
    534     {
    535         BTIF_TRACE_DEBUG("btpan_close_conn: PAN_STATE_OPEN");
    536 
    537         conn->state = PAN_STATE_CLOSE;
    538         btpan_cb.open_count--;
    539 
    540         if (btpan_cb.open_count == 0)
    541         {
    542             destroy_tap_read_thread();
    543             if (btpan_cb.tap_fd != INVALID_FD)
    544             {
    545                 btpan_tap_close(btpan_cb.tap_fd);
    546                 btpan_cb.tap_fd = INVALID_FD;
    547             }
    548         }
    549     }
    550 }
    551 
    552 
    553 static void btpan_cleanup_conn(btpan_conn_t* conn)
    554 {
    555     if (conn)
    556     {
    557         conn->handle = -1;
    558         conn->state = -1;
    559         memset(&conn->peer, 0, sizeof(conn->peer));
    560         memset(&conn->eth_addr, 0, sizeof(conn->eth_addr));
    561         conn->local_role = conn->remote_role = 0;
    562     }
    563 }
    564 
    565 btpan_conn_t* btpan_new_conn(int handle, const BD_ADDR addr, int local_role, int remote_role)
    566 {
    567     for (int i = 0; i < MAX_PAN_CONNS; i++)
    568     {
    569         BTIF_TRACE_DEBUG("conns[%d]:%d", i, btpan_cb.conns[i].handle);
    570         if (btpan_cb.conns[i].handle == -1)
    571         {
    572             BTIF_TRACE_DEBUG("handle:%d, local_role:%d, remote_role:%d", handle, local_role, remote_role);
    573 
    574             btpan_cb.conns[i].handle = handle;
    575             bdcpy(btpan_cb.conns[i].peer, addr);
    576             btpan_cb.conns[i].local_role = local_role;
    577             btpan_cb.conns[i].remote_role = remote_role;
    578             return &btpan_cb.conns[i];
    579         }
    580     }
    581     BTIF_TRACE_DEBUG("MAX_PAN_CONNS:%d exceeded, return NULL as failed", MAX_PAN_CONNS);
    582     return NULL;
    583 }
    584 
    585 void btpan_close_handle(btpan_conn_t *p)
    586 {
    587     BTIF_TRACE_DEBUG("btpan_close_handle : close handle %d", p->handle);
    588     p->handle = -1;
    589     p->local_role = -1;
    590     p->remote_role = -1;
    591     memset(&p->peer, 0, 6);
    592 }
    593 
    594 static inline bool should_forward(tETH_HDR* hdr)
    595 {
    596     uint16_t proto = ntohs(hdr->h_proto);
    597     if (proto == ETH_P_IP || proto == ETH_P_ARP || proto == ETH_P_IPV6)
    598         return true;
    599     BTIF_TRACE_DEBUG("unknown proto:%x", proto);
    600     return false;
    601 }
    602 
    603 static int forward_bnep(tETH_HDR* eth_hdr, BT_HDR *hdr) {
    604     int broadcast = eth_hdr->h_dest[0] & 1;
    605 
    606     // Find the right connection to send this frame over.
    607     for (int i = 0; i < MAX_PAN_CONNS; i++)
    608     {
    609         UINT16 handle = btpan_cb.conns[i].handle;
    610         if (handle != (UINT16)-1 &&
    611                 (broadcast || memcmp(btpan_cb.conns[i].eth_addr, eth_hdr->h_dest, sizeof(BD_ADDR)) == 0
    612                  || memcmp(btpan_cb.conns[i].peer, eth_hdr->h_dest, sizeof(BD_ADDR)) == 0)) {
    613             int result = PAN_WriteBuf(handle, eth_hdr->h_dest, eth_hdr->h_src, ntohs(eth_hdr->h_proto), hdr, 0);
    614             switch (result) {
    615                 case PAN_Q_SIZE_EXCEEDED:
    616                     return FORWARD_CONGEST;
    617                 case PAN_SUCCESS:
    618                     return FORWARD_SUCCESS;
    619                 default:
    620                     return FORWARD_FAILURE;
    621             }
    622         }
    623     }
    624     osi_free(hdr);
    625     return FORWARD_IGNORE;
    626 }
    627 
    628 static void bta_pan_callback_transfer(UINT16 event, char *p_param)
    629 {
    630     tBTA_PAN *p_data = (tBTA_PAN *)p_param;
    631 
    632     switch(event)
    633     {
    634         case BTA_PAN_ENABLE_EVT:
    635             BTIF_TRACE_DEBUG("BTA_PAN_ENABLE_EVT");
    636             break;
    637         case BTA_PAN_SET_ROLE_EVT:
    638             {
    639                 int btpan_role = bta_role_to_btpan(p_data->set_role.role);
    640                 bt_status_t status = p_data->set_role.status == BTA_PAN_SUCCESS ? BT_STATUS_SUCCESS : BT_STATUS_FAIL;
    641                 btpan_control_state_t state = btpan_role == 0 ? BTPAN_STATE_DISABLED : BTPAN_STATE_ENABLED;
    642                 callback.control_state_cb(state, btpan_role, status, TAP_IF_NAME);
    643                 break;
    644             }
    645         case BTA_PAN_OPENING_EVT:
    646             {
    647                 btpan_conn_t* conn;
    648                 bdstr_t bds;
    649                 bdaddr_to_string((bt_bdaddr_t *)p_data->opening.bd_addr, bds, sizeof(bds));
    650                 BTIF_TRACE_DEBUG("BTA_PAN_OPENING_EVT handle %d, addr: %s", p_data->opening.handle, bds);
    651                 conn = btpan_find_conn_addr(p_data->opening.bd_addr);
    652 
    653                 asrt(conn != NULL);
    654                 if (conn)
    655                 {
    656                     conn->handle = p_data->opening.handle;
    657                     int btpan_conn_local_role = bta_role_to_btpan(conn->local_role);
    658                     int btpan_remote_role = bta_role_to_btpan(conn->remote_role);
    659                     callback.connection_state_cb(BTPAN_STATE_CONNECTING, BT_STATUS_SUCCESS,
    660                             (const bt_bdaddr_t*)p_data->opening.bd_addr, btpan_conn_local_role, btpan_remote_role);
    661                 }
    662                 else
    663                     BTIF_TRACE_ERROR("connection not found");
    664                 break;
    665             }
    666         case BTA_PAN_OPEN_EVT:
    667             {
    668                 btpan_connection_state_t state;
    669                 bt_status_t status;
    670                 btpan_conn_t *conn = btpan_find_conn_handle(p_data->open.handle);
    671 
    672                 LOG_VERBOSE(LOG_TAG, "%s pan connection open status: %d", __func__, p_data->open.status);
    673                 if (p_data->open.status == BTA_PAN_SUCCESS)
    674                 {
    675                     state = BTPAN_STATE_CONNECTED;
    676                     status = BT_STATUS_SUCCESS;
    677                     btpan_open_conn(conn, p_data);
    678                 }
    679                 else
    680                 {
    681                     state = BTPAN_STATE_DISCONNECTED;
    682                     status = BT_STATUS_FAIL;
    683                     btpan_cleanup_conn(conn);
    684                 }
    685                 /* debug("BTA_PAN_OPEN_EVT handle:%d, conn:%p",  p_data->open.handle, conn); */
    686                 /* debug("conn bta local_role:%d, bta remote role:%d", conn->local_role, conn->remote_role); */
    687                 int btpan_conn_local_role = bta_role_to_btpan(p_data->open.local_role);
    688                 int btpan_remote_role = bta_role_to_btpan(p_data->open.peer_role);
    689                 callback.connection_state_cb(state, status, (const bt_bdaddr_t*)p_data->open.bd_addr,
    690                         btpan_conn_local_role, btpan_remote_role);
    691                 break;
    692             }
    693         case BTA_PAN_CLOSE_EVT:
    694             {
    695                 LOG_INFO(LOG_TAG, "%s: event = BTA_PAN_CLOSE_EVT handle %d", __FUNCTION__, p_data->close.handle);
    696                 btpan_conn_t* conn = btpan_find_conn_handle(p_data->close.handle);
    697                 btpan_close_conn(conn);
    698 
    699                 if (conn && conn->handle >= 0)
    700                 {
    701                     int btpan_conn_local_role = bta_role_to_btpan(conn->local_role);
    702                     int btpan_remote_role = bta_role_to_btpan(conn->remote_role);
    703                     callback.connection_state_cb(BTPAN_STATE_DISCONNECTED, 0, (const bt_bdaddr_t*)conn->peer,
    704                             btpan_conn_local_role, btpan_remote_role);
    705                     btpan_cleanup_conn(conn);
    706                 }
    707                 else
    708                     BTIF_TRACE_ERROR("pan handle not found (%d)", p_data->close.handle);
    709                 break;
    710             }
    711         default:
    712             BTIF_TRACE_WARNING("Unknown pan event %d", event);
    713             break;
    714     }
    715 }
    716 
    717 static void bta_pan_callback(tBTA_PAN_EVT event, tBTA_PAN *p_data)
    718 {
    719     btif_transfer_context(bta_pan_callback_transfer, event, (char*)p_data, sizeof(tBTA_PAN), NULL);
    720 }
    721 
    722 #define IS_EXCEPTION(e) ((e) & (POLLHUP | POLLRDHUP | POLLERR | POLLNVAL))
    723 static void btu_exec_tap_fd_read(void *p_param) {
    724     struct pollfd ufd;
    725     int fd = PTR_TO_INT(p_param);
    726 
    727     if (fd == INVALID_FD || fd != btpan_cb.tap_fd)
    728         return;
    729 
    730     // Don't occupy BTU context too long, avoid buffer overruns and
    731     // give other profiles a chance to run by limiting the amount of memory
    732     // PAN can use.
    733     for (int i = 0; i < PAN_BUF_MAX && btif_is_enabled() && btpan_cb.flow; i++) {
    734         BT_HDR *buffer = (BT_HDR *)osi_malloc(PAN_BUF_SIZE);
    735         buffer->offset = PAN_MINIMUM_OFFSET;
    736         buffer->len = PAN_BUF_SIZE - sizeof(BT_HDR) - buffer->offset;
    737 
    738         UINT8 *packet = (UINT8 *)buffer + sizeof(BT_HDR) + buffer->offset;
    739 
    740         // If we don't have an undelivered packet left over, pull one from the TAP driver.
    741         // We save it in the congest_packet right away in case we can't deliver it in this
    742         // attempt.
    743         if (!btpan_cb.congest_packet_size) {
    744             ssize_t ret;
    745             OSI_NO_INTR(ret = read(fd, btpan_cb.congest_packet,
    746                                    sizeof(btpan_cb.congest_packet)));
    747             switch (ret) {
    748                 case -1:
    749                     BTIF_TRACE_ERROR("%s unable to read from driver: %s", __func__, strerror(errno));
    750                     osi_free(buffer);
    751                     //add fd back to monitor thread to try it again later
    752                     btsock_thread_add_fd(pan_pth, fd, 0, SOCK_THREAD_FD_RD, 0);
    753                     return;
    754                 case 0:
    755                     BTIF_TRACE_WARNING("%s end of file reached.", __func__);
    756                     osi_free(buffer);
    757                     //add fd back to monitor thread to process the exception
    758                     btsock_thread_add_fd(pan_pth, fd, 0, SOCK_THREAD_FD_RD, 0);
    759                     return;
    760                 default:
    761                     btpan_cb.congest_packet_size = ret;
    762                     break;
    763             }
    764         }
    765 
    766         memcpy(packet, btpan_cb.congest_packet, MIN(btpan_cb.congest_packet_size, buffer->len));
    767         buffer->len = MIN(btpan_cb.congest_packet_size, buffer->len);
    768 
    769         if (buffer->len > sizeof(tETH_HDR) && should_forward((tETH_HDR *)packet)) {
    770             // Extract the ethernet header from the buffer since the PAN_WriteBuf inside
    771             // forward_bnep can't handle two pointers that point inside the same GKI buffer.
    772             tETH_HDR hdr;
    773             memcpy(&hdr, packet, sizeof(tETH_HDR));
    774 
    775             // Skip the ethernet header.
    776             buffer->len -= sizeof(tETH_HDR);
    777             buffer->offset += sizeof(tETH_HDR);
    778             if (forward_bnep(&hdr, buffer) != FORWARD_CONGEST)
    779                 btpan_cb.congest_packet_size = 0;
    780         } else {
    781             BTIF_TRACE_WARNING("%s dropping packet of length %d", __func__, buffer->len);
    782             btpan_cb.congest_packet_size = 0;
    783             osi_free(buffer);
    784         }
    785 
    786         // Bail out of the loop if reading from the TAP fd would block.
    787         ufd.fd = fd;
    788         ufd.events = POLLIN;
    789         ufd.revents = 0;
    790 
    791         int ret;
    792         OSI_NO_INTR(ret = poll(&ufd, 1, 0));
    793         if (ret <= 0 || IS_EXCEPTION(ufd.revents))
    794             break;
    795     }
    796 
    797     if (btpan_cb.flow) {
    798         //add fd back to monitor thread when the flow is on
    799         btsock_thread_add_fd(pan_pth, fd, 0, SOCK_THREAD_FD_RD, 0);
    800     }
    801 }
    802 
    803 static void btif_pan_close_all_conns() {
    804     if (!stack_initialized)
    805         return;
    806 
    807     for (int i = 0; i < MAX_PAN_CONNS; ++i)
    808     {
    809         if (btpan_cb.conns[i].handle != -1)
    810             BTA_PanClose(btpan_cb.conns[i].handle);
    811     }
    812 }
    813 
    814 static void btpan_tap_fd_signaled(int fd, int type, int flags, uint32_t user_id) {
    815     assert(btpan_cb.tap_fd == INVALID_FD || btpan_cb.tap_fd == fd);
    816 
    817     if (btpan_cb.tap_fd != fd) {
    818         BTIF_TRACE_WARNING("%s Signaled on mismatched fds exp:%d act:%d\n",
    819                 __func__, btpan_cb.tap_fd, fd);
    820         return;
    821     }
    822 
    823     if (flags & SOCK_THREAD_FD_EXCEPTION) {
    824         btpan_cb.tap_fd = INVALID_FD;
    825         btpan_tap_close(fd);
    826         btif_pan_close_all_conns();
    827     } else if (flags & SOCK_THREAD_FD_RD)
    828         bta_dmexecutecallback(btu_exec_tap_fd_read, INT_TO_PTR(fd));
    829 }
    830