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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 #include <hardware/bluetooth.h>
     28 #include <hardware/bt_pan.h>
     29 #include <assert.h>
     30 #include <signal.h>
     31 #include <ctype.h>
     32 #include <sys/select.h>
     33 #include <sys/poll.h>
     34 #include <sys/ioctl.h>
     35 #include <netinet/in.h>
     36 #include <netdb.h>
     37 #include <stdio.h>
     38 #include <errno.h>
     39 #include <fcntl.h>
     40 #include <sys/socket.h>
     41 #include <sys/wait.h>
     42 #include <net/if.h>
     43 #include <linux/sockios.h>
     44 #include <sys/prctl.h>
     45 #include <linux/if.h>
     46 #include <linux/if_tun.h>
     47 #include <linux/if_ether.h>
     48 
     49 #define LOG_TAG "BTIF_PAN"
     50 #include "btif_common.h"
     51 #include "btif_util.h"
     52 #include "btm_api.h"
     53 #include "bd.h"
     54 
     55 #include "bta_api.h"
     56 #include "bta_pan_api.h"
     57 #include "btif_sock_thread.h"
     58 #include "btif_sock_util.h"
     59 #include "btif_pan_internal.h"
     60 #include "gki.h"
     61 
     62 #define FORWARD_IGNORE        1
     63 #define FORWARD_SUCCESS       0
     64 #define FORWARD_FAILURE     (-1)
     65 #define FORWARD_CONGEST     (-2)
     66 //#define PANU_DISABLED TRUE
     67 
     68 #if (PAN_NAP_DISABLED == TRUE) && (PANU_DISABLED == TRUE)
     69 #define BTPAN_LOCAL_ROLE BTPAN_ROLE_NONE
     70 #elif PAN_NAP_DISABLED == TRUE
     71 #define BTPAN_LOCAL_ROLE BTPAN_ROLE_PANU
     72 #elif PANU_DISABLED == TRUE
     73 #define BTPAN_LOCAL_ROLE BTPAN_ROLE_PANNAP
     74 #else
     75 #define BTPAN_LOCAL_ROLE (BTPAN_ROLE_PANU | BTPAN_ROLE_PANNAP)
     76 #endif
     77 
     78 #define asrt(s) if(!(s)) BTIF_TRACE_ERROR("btif_pan: ## %s assert %s failed at line:%d ##",__FUNCTION__, #s, __LINE__)
     79 
     80 #define MIN(x, y) (((x) < (y)) ? (x) : (y))
     81 
     82 btpan_cb_t btpan_cb;
     83 
     84 BD_ADDR local_addr;
     85 static int jni_initialized, stack_initialized;
     86 static bt_status_t btpan_jni_init(const btpan_callbacks_t* callbacks);
     87 static void btpan_jni_cleanup();
     88 static bt_status_t btpan_connect(const bt_bdaddr_t *bd_addr, int local_role, int remote_role);
     89 static bt_status_t btpan_disconnect(const bt_bdaddr_t *bd_addr);
     90 static bt_status_t btpan_enable(int local_role);
     91 static int btpan_get_local_role(void);
     92 
     93 static void btpan_tap_fd_signaled(int fd, int type, int flags, uint32_t user_id);
     94 static void btpan_cleanup_conn(btpan_conn_t* conn);
     95 static void bta_pan_callback(tBTA_PAN_EVT event, tBTA_PAN *p_data);
     96 static void btu_exec_tap_fd_read(void *p_param);
     97 
     98 static btpan_interface_t pan_if = {
     99     sizeof(pan_if),
    100     btpan_jni_init,
    101     btpan_enable,
    102     btpan_get_local_role,
    103     btpan_connect,
    104     btpan_disconnect,
    105     btpan_jni_cleanup
    106 };
    107 
    108 btpan_interface_t *btif_pan_get_interface()
    109 {
    110     return &pan_if;
    111 }
    112 
    113 /*******************************************************************************
    114  **
    115  ** Function        btif_pan_init
    116  **
    117  ** Description     initializes the pan interface
    118  **
    119  ** Returns         bt_status_t
    120  **
    121  *******************************************************************************/
    122 void btif_pan_init()
    123 {
    124     BTIF_TRACE_DEBUG("jni_initialized = %d, btpan_cb.enabled:%d", jni_initialized, btpan_cb.enabled);
    125     stack_initialized = TRUE;
    126     if (jni_initialized && !btpan_cb.enabled)
    127     {
    128         BTIF_TRACE_DEBUG("Enabling PAN....");
    129         memset(&btpan_cb, 0, sizeof(btpan_cb));
    130         btpan_cb.tap_fd = -1;
    131         btpan_cb.flow = 1;
    132         int i;
    133         for(i = 0; i < MAX_PAN_CONNS; i++)
    134             btpan_cleanup_conn(&btpan_cb.conns[i]);
    135         BTA_PanEnable(bta_pan_callback);
    136         btpan_cb.enabled = 1;
    137         btpan_enable(BTPAN_LOCAL_ROLE);
    138     }
    139 }
    140 
    141 static void pan_disable()
    142 {
    143     if(btpan_cb.enabled)
    144     {
    145         btpan_cb.enabled = 0;
    146         BTA_PanDisable();
    147         if(btpan_cb.tap_fd != -1)
    148         {
    149             btpan_tap_close(btpan_cb.tap_fd);
    150             btpan_cb.tap_fd = -1;
    151         }
    152     }
    153 }
    154 
    155 void btif_pan_cleanup()
    156 {
    157     if(stack_initialized)
    158     {
    159         //bt is shuting down, invalid all bta pan handles
    160         int i;
    161         for(i = 0; i < MAX_PAN_CONNS; i++)
    162             btpan_cleanup_conn(&btpan_cb.conns[i]);
    163         pan_disable();
    164     }
    165     stack_initialized = FALSE;
    166 }
    167 
    168 static btpan_callbacks_t callback;
    169 static bt_status_t btpan_jni_init(const btpan_callbacks_t* callbacks)
    170 {
    171     BTIF_TRACE_DEBUG("stack_initialized = %d, btpan_cb.enabled:%d", stack_initialized, btpan_cb.enabled);
    172     jni_initialized = TRUE;
    173     if(stack_initialized && !btpan_cb.enabled)
    174         btif_pan_init();
    175     callback = *callbacks;
    176     return BT_STATUS_SUCCESS;
    177 }
    178 
    179 static void btpan_jni_cleanup()
    180 {
    181     pan_disable();
    182     jni_initialized = FALSE;
    183 }
    184 
    185 static inline int bta_role_to_btpan(int bta_pan_role)
    186 {
    187     int btpan_role = 0;
    188     BTIF_TRACE_DEBUG("bta_pan_role:0x%x", bta_pan_role);
    189     if(bta_pan_role & PAN_ROLE_NAP_SERVER)
    190     {
    191         btpan_role |= BTPAN_ROLE_PANNAP;
    192     }
    193     if(bta_pan_role & PAN_ROLE_CLIENT)
    194     {
    195         btpan_role |= BTPAN_ROLE_PANU;
    196     }
    197     return btpan_role;
    198 }
    199 
    200 static inline int btpan_role_to_bta(int btpan_role)
    201 {
    202     int bta_pan_role = PAN_ROLE_INACTIVE;
    203     BTIF_TRACE_DEBUG("btpan_role:0x%x", btpan_role);
    204     if(btpan_role & BTPAN_ROLE_PANNAP)
    205     {
    206         bta_pan_role |= PAN_ROLE_NAP_SERVER;
    207     }
    208     if(btpan_role & BTPAN_ROLE_PANU)
    209     {
    210         bta_pan_role |= PAN_ROLE_CLIENT;
    211     }
    212     return bta_pan_role;
    213 }
    214 
    215 static volatile int btpan_dev_local_role;
    216 static tBTA_PAN_ROLE_INFO bta_panu_info = {PANU_SERVICE_NAME, 0, PAN_SECURITY};
    217 static tBTA_PAN_ROLE_INFO bta_pan_nap_info = {PAN_NAP_SERVICE_NAME, 1, PAN_SECURITY};
    218 
    219 static bt_status_t btpan_enable(int local_role)
    220 {
    221     int bta_pan_role;
    222     BTIF_TRACE_DEBUG("local_role:%d", local_role);
    223     bta_pan_role = btpan_role_to_bta(local_role);
    224 #if BTA_PAN_INCLUDED == TRUE
    225     BTA_PanSetRole(bta_pan_role, &bta_panu_info, NULL, &bta_pan_nap_info);
    226     btpan_dev_local_role = local_role;
    227     return BT_STATUS_SUCCESS;
    228 #else
    229     return BT_STATUS_FAIL;
    230 #endif
    231 }
    232 
    233 static int btpan_get_local_role()
    234 {
    235     BTIF_TRACE_DEBUG("btpan_dev_local_role:%d", btpan_dev_local_role);
    236     return btpan_dev_local_role;
    237 }
    238 
    239 static bt_status_t btpan_connect(const bt_bdaddr_t *bd_addr, int local_role, int remote_role)
    240 {
    241     BTIF_TRACE_DEBUG("local_role:%d, remote_role:%d", local_role, remote_role);
    242     int bta_local_role = btpan_role_to_bta(local_role);
    243     int bta_remote_role = btpan_role_to_bta(remote_role);
    244     btpan_new_conn(-1, bd_addr->address, bta_local_role, bta_remote_role);
    245     BTA_PanOpen((UINT8*)bd_addr->address, bta_local_role, bta_remote_role);
    246     return BT_STATUS_SUCCESS;
    247 }
    248 
    249 static void btif_in_pan_generic_evt(UINT16 event, char *p_param)
    250 {
    251     BTIF_TRACE_EVENT("%s: event=%d", __FUNCTION__, event);
    252     switch (event) {
    253         case BTIF_PAN_CB_DISCONNECTING:
    254         {
    255             bt_bdaddr_t *bd_addr = (bt_bdaddr_t*)p_param;
    256             btpan_conn_t* conn = btpan_find_conn_addr(bd_addr->address);
    257             int btpan_conn_local_role;
    258             int btpan_remote_role;
    259             asrt(conn != NULL);
    260             if (conn) {
    261                 btpan_conn_local_role = bta_role_to_btpan(conn->local_role);
    262                 btpan_remote_role = bta_role_to_btpan(conn->remote_role);
    263                 callback.connection_state_cb(BTPAN_STATE_DISCONNECTING, BT_STATUS_SUCCESS,
    264                         (const bt_bdaddr_t*)conn->peer, btpan_conn_local_role, btpan_remote_role);
    265             }
    266         } break;
    267         default:
    268         {
    269             BTIF_TRACE_WARNING("%s : Unknown event 0x%x", __FUNCTION__, event);
    270         }
    271         break;
    272     }
    273 }
    274 
    275 static bt_status_t btpan_disconnect(const bt_bdaddr_t *bd_addr)
    276 {
    277     btpan_conn_t* conn = btpan_find_conn_addr(bd_addr->address);
    278     if(conn && conn->handle >= 0)
    279     {
    280         BTA_PanClose(conn->handle);
    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         return BT_STATUS_SUCCESS;
    285     }
    286     return BT_STATUS_FAIL;
    287 }
    288 
    289 static int pan_pth = -1;
    290 void create_tap_read_thread(int tap_fd)
    291 {
    292     if(pan_pth < 0)
    293         pan_pth = btsock_thread_create(btpan_tap_fd_signaled, NULL);
    294     if(pan_pth >= 0)
    295         btsock_thread_add_fd(pan_pth, tap_fd, 0, SOCK_THREAD_FD_RD, 0);
    296 }
    297 
    298 void destroy_tap_read_thread(void)
    299 {
    300     if(pan_pth >= 0)
    301     {
    302         btsock_thread_exit(pan_pth);
    303         pan_pth = -1;
    304     }
    305 }
    306 
    307 static int tap_if_up(const char *devname, BD_ADDR addr)
    308 {
    309     struct ifreq ifr;
    310     int sk, err;
    311 
    312     sk = socket(AF_INET, SOCK_DGRAM, 0);
    313 
    314     //set mac addr
    315     memset(&ifr, 0, sizeof(ifr));
    316     strncpy(ifr.ifr_name, devname, IFNAMSIZ - 1);
    317     err = ioctl(sk, SIOCGIFHWADDR, &ifr);
    318     if(err < 0)
    319     {
    320         BTIF_TRACE_ERROR("Could not get network hardware for interface:%s, errno:%s", devname, strerror(errno));
    321         close(sk);
    322         return -1;
    323     }
    324     /* debug("found mac address for interface:%s = %02x:%02x:%02x:%02x:%02x:%02x", devname, */
    325     /*         ifr.ifr_hwaddr.sa_data[0], ifr.ifr_hwaddr.sa_data[1], ifr.ifr_hwaddr.sa_data[2], */
    326     /*         ifr.ifr_hwaddr.sa_data[3], ifr.ifr_hwaddr.sa_data[4], ifr.ifr_hwaddr.sa_data[5]); */
    327     strncpy(ifr.ifr_name, devname, IFNAMSIZ - 1);
    328     memcpy(ifr.ifr_hwaddr.sa_data, addr, 6);
    329     /* debug("setting bt address for interface:%s = %02x:%02x:%02x:%02x:%02x:%02x", devname, */
    330     /*         ifr.ifr_hwaddr.sa_data[0], ifr.ifr_hwaddr.sa_data[1], ifr.ifr_hwaddr.sa_data[2], */
    331     /*         ifr.ifr_hwaddr.sa_data[3], ifr.ifr_hwaddr.sa_data[4], ifr.ifr_hwaddr.sa_data[5]); */
    332 
    333     /* The IEEE has specified that the most significant bit of the most significant byte is used to
    334      * determine a multicast address. If its a 1, that means multicast, 0 means unicast.
    335      * Kernel returns an error if we try to set a multicast address for the tun-tap ethernet interface.
    336      * Mask this bit to avoid any issue with auto generated address.
    337      */
    338     if (ifr.ifr_hwaddr.sa_data[0] & 0x01) {
    339         BTIF_TRACE_WARNING("Not a unicast MAC address, force multicast bit flipping");
    340         ifr.ifr_hwaddr.sa_data[0] &= ~0x01;
    341     }
    342 
    343     err = ioctl(sk, SIOCSIFHWADDR, (caddr_t)&ifr);
    344 
    345     if (err < 0) {
    346         BTIF_TRACE_ERROR("Could not set bt address for interface:%s, errno:%s", devname, strerror(errno));
    347         close(sk);
    348         return -1;
    349     }
    350 
    351     //bring it up
    352     memset(&ifr, 0, sizeof(ifr));
    353     strncpy(ifr.ifr_name, devname, IF_NAMESIZE - 1);
    354 
    355     ifr.ifr_flags |= IFF_UP;
    356     ifr.ifr_flags |= IFF_MULTICAST;
    357 
    358     err = ioctl(sk, SIOCSIFFLAGS, (caddr_t) &ifr);
    359 
    360 
    361     if (err < 0) {
    362         BTIF_TRACE_ERROR("Could not bring up network interface:%s, errno:%d", devname, errno);
    363         close(sk);
    364         return -1;
    365     }
    366     close(sk);
    367     BTIF_TRACE_DEBUG("network interface: %s is up", devname);
    368     return 0;
    369 }
    370 
    371 static int tap_if_down(const char *devname)
    372 {
    373     struct ifreq ifr;
    374     int sk, err;
    375 
    376     sk = socket(AF_INET, SOCK_DGRAM, 0);
    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     err = 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, (void *)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     //system("insmod /system/lib/modules/tun.ko");
    410     if( (fd = open(clonedev, O_RDWR)) < 0 ) {
    411 
    412         BTIF_TRACE_DEBUG("could not open %s, err:%d", clonedev, errno);
    413         return fd;
    414     }
    415 
    416     memset(&ifr, 0, sizeof(ifr));
    417     ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
    418 
    419     strncpy(ifr.ifr_name, TAP_IF_NAME, IFNAMSIZ);
    420 
    421     /* try to create the device */
    422     if( (err = ioctl(fd, TUNSETIFF, (void *) &ifr)) < 0 )//|| tap_setup_ip(TAP_IF_NAME) == FALSE)
    423     {
    424         BTIF_TRACE_DEBUG("ioctl error:%d, errno:%s", err, strerror(errno));
    425         close(fd);
    426         return err;
    427     }
    428     BTM_GetLocalDeviceAddr (local_addr);
    429     if(tap_if_up(TAP_IF_NAME, local_addr) == 0)
    430     {
    431         int flags = fcntl(fd, F_GETFL, 0);
    432         fcntl(fd, F_SETFL, flags | O_NONBLOCK);
    433         return fd;
    434     }
    435     BTIF_TRACE_ERROR("can not bring up tap interface:%s", TAP_IF_NAME);
    436     close(fd);
    437     return -1;
    438 }
    439 
    440 int btpan_tap_send(int tap_fd, const BD_ADDR src, const BD_ADDR dst, UINT16 proto, const char* buf,
    441                     UINT16 len, BOOLEAN ext, BOOLEAN forward)
    442 {
    443     UNUSED(ext);
    444     UNUSED(forward);
    445     if(tap_fd != -1)
    446     {
    447         tETH_HDR eth_hdr;
    448         //if(is_empty_eth_addr(dst))
    449         //    memcpy(&eth_hdr.h_dest, local_addr, ETH_ADDR_LEN);
    450         //else
    451         memcpy(&eth_hdr.h_dest, dst, ETH_ADDR_LEN);
    452         memcpy(&eth_hdr.h_src, src, ETH_ADDR_LEN);
    453         eth_hdr.h_proto = htons(proto);
    454         char packet[2000];
    455         memcpy(packet, &eth_hdr, sizeof(tETH_HDR));
    456         if(len > 2000)
    457         {
    458             ALOGE("btpan_tap_send eth packet size:%d is exceeded limit!", len);
    459             return -1;
    460         }
    461         memcpy(packet + sizeof(tETH_HDR), buf, len);
    462 
    463         /* Send data to network interface */
    464         //btnet_send(btpan_cb.conn[i].sock.sock, &buffer, (len + sizeof(tETH_HDR)));
    465         //dump_bin("packet to network", packet, len + sizeof(tETH_HDR));
    466         int ret = write(tap_fd, packet, len + sizeof(tETH_HDR));
    467         BTIF_TRACE_DEBUG("ret:%d", ret);
    468         return ret;
    469     }
    470     return -1;
    471 
    472 }
    473 
    474 int btpan_tap_close(int fd)
    475 {
    476     tap_if_down(TAP_IF_NAME);
    477     close(fd);
    478     if(pan_pth >= 0)
    479         btsock_thread_wakeup(pan_pth);
    480     return 0;
    481 }
    482 
    483 btpan_conn_t * btpan_find_conn_handle(UINT16 handle)
    484 {
    485     int i;
    486     for(i = 0; i < MAX_PAN_CONNS; i++)
    487         if(btpan_cb.conns[i].handle == handle)
    488             return &btpan_cb.conns[i];
    489     return NULL;
    490 }
    491 
    492 btpan_conn_t* btpan_find_conn_addr(const BD_ADDR addr)
    493 {
    494     int i;
    495     for(i = 0; i < MAX_PAN_CONNS; i++)
    496         if(memcmp(btpan_cb.conns[i].peer, addr, sizeof(BD_ADDR)) == 0)
    497             return &btpan_cb.conns[i];
    498     return NULL;
    499 }
    500 
    501 static void btpan_cleanup_conn(btpan_conn_t* conn)
    502 {
    503     if(conn)
    504     {
    505         conn->handle = -1;
    506         conn->state = -1;
    507         memset(&conn->peer, 0, sizeof(conn->peer));
    508         memset(&conn->eth_addr, 0, sizeof(conn->eth_addr));
    509         conn->local_role = conn->remote_role = 0;
    510     }
    511 }
    512 
    513 btpan_conn_t* btpan_new_conn(int handle, const BD_ADDR addr, int local_role, int remote_role )
    514 {
    515     int i;
    516     for(i = 0; i < MAX_PAN_CONNS; i++)
    517     {
    518         BTIF_TRACE_DEBUG("conns[%d]:%d", i, btpan_cb.conns[i].handle);
    519         if(btpan_cb.conns[i].handle == -1)
    520         {
    521             BTIF_TRACE_DEBUG("handle:%d, local_role:%d, remote_role:%d", handle, local_role, remote_role);
    522 
    523             btpan_cb.conns[i].handle = handle;
    524             bdcpy(btpan_cb.conns[i].peer, addr);
    525             btpan_cb.conns[i].local_role = local_role;
    526             btpan_cb.conns[i].remote_role = remote_role;
    527             return &btpan_cb.conns[i];
    528         }
    529     }
    530     BTIF_TRACE_DEBUG("MAX_PAN_CONNS:%d exceeded, return NULL as failed", MAX_PAN_CONNS);
    531     return NULL;
    532 }
    533 
    534 void btpan_close_handle(btpan_conn_t *p)
    535 {
    536     BTIF_TRACE_DEBUG("btpan_close_handle : close handle %d", p->handle);
    537     p->handle = -1;
    538     p->local_role = -1;
    539     p->remote_role = -1;
    540     memset(&p->peer, 0, 6);
    541 }
    542 
    543 static inline bool should_forward(tETH_HDR* hdr)
    544 {
    545     uint16_t proto = ntohs(hdr->h_proto);
    546     if(proto == ETH_P_IP || proto == ETH_P_ARP || proto == ETH_P_IPV6)
    547         return true;
    548     BTIF_TRACE_DEBUG("unknown proto:%x", proto);
    549     return false;
    550 }
    551 
    552 static int forward_bnep(tETH_HDR* eth_hdr, BT_HDR *hdr) {
    553     int broadcast = eth_hdr->h_dest[0] & 1;
    554     int i;
    555 
    556     // Find the right connection to send this frame over.
    557     for (i = 0; i < MAX_PAN_CONNS; i++) {
    558         UINT16 handle = btpan_cb.conns[i].handle;
    559         if (handle != (UINT16)-1 &&
    560                 (broadcast || memcmp(btpan_cb.conns[i].eth_addr, eth_hdr->h_dest, sizeof(BD_ADDR)) == 0
    561                  || memcmp(btpan_cb.conns[i].peer, eth_hdr->h_dest, sizeof(BD_ADDR)) == 0)) {
    562             int result = PAN_WriteBuf(handle, eth_hdr->h_dest, eth_hdr->h_src, ntohs(eth_hdr->h_proto), hdr, 0);
    563             switch (result) {
    564                 case PAN_Q_SIZE_EXCEEDED:
    565                     return FORWARD_CONGEST;
    566                 case PAN_SUCCESS:
    567                     return FORWARD_SUCCESS;
    568                 default:
    569                     return FORWARD_FAILURE;
    570             }
    571         }
    572     }
    573     GKI_freebuf(hdr);
    574     return FORWARD_IGNORE;
    575 }
    576 
    577 static void bta_pan_callback_transfer(UINT16 event, char *p_param)
    578 {
    579     tBTA_PAN *p_data = (tBTA_PAN *)p_param;
    580     switch(event)
    581     {
    582         case BTA_PAN_ENABLE_EVT:
    583             BTIF_TRACE_DEBUG("BTA_PAN_ENABLE_EVT");
    584             break;
    585         case BTA_PAN_SET_ROLE_EVT:
    586             {
    587                 int btpan_role = bta_role_to_btpan(p_data->set_role.role);
    588                 bt_status_t status = p_data->set_role.status == BTA_PAN_SUCCESS ? BT_STATUS_SUCCESS : BT_STATUS_FAIL;
    589                 btpan_control_state_t state = btpan_role == 0 ? BTPAN_STATE_DISABLED : BTPAN_STATE_ENABLED;
    590                 callback.control_state_cb(state, btpan_role, status, TAP_IF_NAME);
    591                 break;
    592             }
    593         case BTA_PAN_OPENING_EVT:
    594             {
    595                 btpan_conn_t* conn;
    596                 bdstr_t bds;
    597                 bd2str((bt_bdaddr_t*)p_data->opening.bd_addr, &bds);
    598                 BTIF_TRACE_DEBUG("BTA_PAN_OPENING_EVT handle %d, addr: %s", p_data->opening.handle, bds);
    599                 conn = btpan_find_conn_addr(p_data->opening.bd_addr);
    600 
    601                 asrt(conn != NULL);
    602                 if (conn)
    603                 {
    604                     conn->handle = p_data->opening.handle;
    605                     int btpan_conn_local_role = bta_role_to_btpan(conn->local_role);
    606                     int btpan_remote_role = bta_role_to_btpan(conn->remote_role);
    607                     callback.connection_state_cb(BTPAN_STATE_CONNECTING, BT_STATUS_SUCCESS,
    608                             (const bt_bdaddr_t*)p_data->opening.bd_addr, btpan_conn_local_role, btpan_remote_role);
    609                 }
    610                 else
    611                     BTIF_TRACE_ERROR("connection not found");
    612                 break;
    613             }
    614         case BTA_PAN_OPEN_EVT:
    615             {
    616                 /* debug("BTA_PAN_OPEN_EVT, open status:%d, bd_addr = [%02X:%02X:%02X:%02X:%02X:%02X]", */
    617                 /*         p_data->open.status, */
    618                 /*         p_data->open.bd_addr[0], p_data->open.bd_addr[1], p_data->open.bd_addr[2], */
    619                 /*         p_data->open.bd_addr[3], p_data->open.bd_addr[4], p_data->open.bd_addr[5]); */
    620                 btpan_connection_state_t state;
    621                 bt_status_t status;
    622                 btpan_conn_t *conn = btpan_find_conn_handle(p_data->open.handle);
    623 
    624                 ALOGV("%s pan connection open status: %d", __func__, p_data->open.status);
    625                 if(p_data->open.status == BTA_PAN_SUCCESS)
    626                 {
    627                     state = BTPAN_STATE_CONNECTED;
    628                     status = BT_STATUS_SUCCESS;
    629                 }
    630                 else
    631                 {
    632                     state = BTPAN_STATE_DISCONNECTED;
    633                     status = BT_STATUS_FAIL;
    634                     btpan_cleanup_conn(conn);
    635                 }
    636                 /* debug("BTA_PAN_OPEN_EVT handle:%d, conn:%p",  p_data->open.handle, conn); */
    637                 /* debug("conn bta local_role:%d, bta remote role:%d", conn->local_role, conn->remote_role); */
    638                 int btpan_conn_local_role = bta_role_to_btpan(p_data->open.local_role);
    639                 /* debug("bta local_role:%d, bta remote role:%d", p_data->open.local_role, p_data->open.peer_role); */
    640                 int btpan_remote_role = bta_role_to_btpan(p_data->open.peer_role);
    641                 callback.connection_state_cb(state, status, (const bt_bdaddr_t*)p_data->open.bd_addr,
    642                         btpan_conn_local_role, btpan_remote_role);
    643                 break;
    644             }
    645         case BTA_PAN_CLOSE_EVT:
    646             {
    647                 btpan_conn_t* conn = btpan_find_conn_handle(p_data->close.handle);
    648 
    649                 ALOGI("%s: event = BTA_PAN_CLOSE_EVT handle %d", __FUNCTION__, p_data->close.handle);
    650 
    651                 if(conn && conn->handle >= 0)
    652                 {
    653                     /* debug("BTA_PAN_CLOSE_EVT, conn local_role:%d, remote_role:%d", conn->local_role, conn->remote_role); */
    654                     int btpan_conn_local_role = bta_role_to_btpan(conn->local_role);
    655                     int btpan_remote_role = bta_role_to_btpan(conn->remote_role);
    656                     callback.connection_state_cb(BTPAN_STATE_DISCONNECTED, 0, (const bt_bdaddr_t*)conn->peer,
    657                             btpan_conn_local_role, btpan_remote_role);
    658                     btpan_cleanup_conn(conn);
    659                 }
    660                 else
    661                     BTIF_TRACE_ERROR("pan handle not found (%d)", p_data->close.handle);
    662                 break;
    663             }
    664         default:
    665             BTIF_TRACE_WARNING("Unknown pan event %d", event);
    666             break;
    667     }
    668 }
    669 
    670 static void bta_pan_callback(tBTA_PAN_EVT event, tBTA_PAN *p_data)
    671 {
    672     btif_transfer_context(bta_pan_callback_transfer, event, (char*)p_data, sizeof(tBTA_PAN), NULL);
    673 }
    674 
    675 #define IS_EXCEPTION(e) ((e) & (POLLHUP | POLLRDHUP | POLLERR | POLLNVAL))
    676 static void btu_exec_tap_fd_read(void *p_param) {
    677     struct pollfd ufd;
    678     int fd = (int)p_param;
    679 
    680     if (fd == -1 || fd != btpan_cb.tap_fd)
    681         return;
    682 
    683     // Don't occupy BTU context too long, avoid GKI buffer overruns and
    684     // give other profiles a chance to run by limiting the amount of memory
    685     // PAN can use from the shared pool buffer.
    686     for(int i = 0; i < PAN_POOL_MAX && btif_is_enabled() && btpan_cb.flow; i++) {
    687         BT_HDR *buffer = (BT_HDR *)GKI_getpoolbuf(PAN_POOL_ID);
    688         if (!buffer) {
    689             BTIF_TRACE_WARNING("%s unable to allocate buffer for packet.", __func__);
    690             break;
    691         }
    692         buffer->offset = PAN_MINIMUM_OFFSET;
    693         buffer->len = GKI_get_buf_size(buffer) - sizeof(BT_HDR) - buffer->offset;
    694 
    695         UINT8 *packet = (UINT8 *)buffer + sizeof(BT_HDR) + buffer->offset;
    696 
    697         // If we don't have an undelivered packet left over, pull one from the TAP driver.
    698         // We save it in the congest_packet right away in case we can't deliver it in this
    699         // attempt.
    700         if (!btpan_cb.congest_packet_size) {
    701             ssize_t ret = read(fd, btpan_cb.congest_packet, sizeof(btpan_cb.congest_packet));
    702             switch (ret) {
    703                 case -1:
    704                     BTIF_TRACE_ERROR("%s unable to read from driver: %s", __func__, strerror(errno));
    705                     GKI_freebuf(buffer);
    706                     //add fd back to monitor thread to try it again later
    707                     btsock_thread_add_fd(pan_pth, fd, 0, SOCK_THREAD_FD_RD, 0);
    708                     return;
    709                 case 0:
    710                     BTIF_TRACE_WARNING("%s end of file reached.", __func__);
    711                     GKI_freebuf(buffer);
    712                     //add fd back to monitor thread to process the exception
    713                     btsock_thread_add_fd(pan_pth, fd, 0, SOCK_THREAD_FD_RD, 0);
    714                     return;
    715                 default:
    716                     btpan_cb.congest_packet_size = ret;
    717                     break;
    718             }
    719         }
    720 
    721         memcpy(packet, btpan_cb.congest_packet, MIN(btpan_cb.congest_packet_size, buffer->len));
    722         buffer->len = MIN(btpan_cb.congest_packet_size, buffer->len);
    723 
    724         if (buffer->len > sizeof(tETH_HDR) && should_forward((tETH_HDR *)packet)) {
    725             // Extract the ethernet header from the buffer since the PAN_WriteBuf inside
    726             // forward_bnep can't handle two pointers that point inside the same GKI buffer.
    727             tETH_HDR hdr;
    728             memcpy(&hdr, packet, sizeof(tETH_HDR));
    729 
    730             // Skip the ethernet header.
    731             buffer->len -= sizeof(tETH_HDR);
    732             buffer->offset += sizeof(tETH_HDR);
    733             if (forward_bnep(&hdr, buffer) != FORWARD_CONGEST)
    734                 btpan_cb.congest_packet_size = 0;
    735         } else {
    736             BTIF_TRACE_WARNING("%s dropping packet of length %d", __func__, buffer->len);
    737             btpan_cb.congest_packet_size = 0;
    738             GKI_freebuf(buffer);
    739         }
    740 
    741         // Bail out of the loop if reading from the TAP fd would block.
    742         ufd.fd = fd;
    743         ufd.events = POLLIN;
    744         ufd.revents = 0;
    745         if(poll(&ufd, 1, 0) <= 0 || IS_EXCEPTION(ufd.revents))
    746             break;
    747     }
    748     //add fd back to monitor thread
    749     btsock_thread_add_fd(pan_pth, fd, 0, SOCK_THREAD_FD_RD, 0);
    750 }
    751 
    752 static void btif_pan_close_all_conns() {
    753     int i;
    754     if (!stack_initialized)
    755         return;
    756 
    757     for (i = 0; i < MAX_PAN_CONNS; ++i)
    758         if (btpan_cb.conns[i].handle != -1)
    759             BTA_PanClose(btpan_cb.conns[i].handle);
    760 }
    761 
    762 static void btpan_tap_fd_signaled(int fd, int type, int flags, uint32_t user_id) {
    763     assert(btpan_cb.tap_fd == fd);
    764 
    765     if (btpan_cb.tap_fd != fd)
    766         return;
    767 
    768     if(flags & SOCK_THREAD_FD_EXCEPTION) {
    769         btpan_cb.tap_fd = -1;
    770         btpan_tap_close(fd);
    771         btif_pan_close_all_conns();
    772     } else if(flags & SOCK_THREAD_FD_RD)
    773         bta_dmexecutecallback(btu_exec_tap_fd_read, (void *)fd);
    774 }
    775