/*      $NetBSD: pcap-bt-linux.c,v 1.8 2024/09/02 15:33:37 christos Exp $       */

/*
* Copyright (c) 2006 Paolo Abeni (Italy)
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* Bluetooth sniffing API implementation for Linux platform
* By Paolo Abeni <[email protected]>
*
*/
#include <sys/cdefs.h>
__RCSID("$NetBSD: pcap-bt-linux.c,v 1.8 2024/09/02 15:33:37 christos Exp $");

#include <config.h>

#include "pcap-int.h"
#include "pcap-bt-linux.h"
#include "pcap/bluetooth.h"
#include "diag-control.h"

#include <errno.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <arpa/inet.h>

#include <bluetooth/bluetooth.h>
#include <bluetooth/hci.h>

#define BT_IFACE "bluetooth"
#define BT_CTRL_SIZE 128

/* forward declaration */
static int bt_activate(pcap_t *);
static int bt_read_linux(pcap_t *, int , pcap_handler , u_char *);
static int bt_inject_linux(pcap_t *, const void *, int);
static int bt_setdirection_linux(pcap_t *, pcap_direction_t);
static int bt_stats_linux(pcap_t *, struct pcap_stat *);

/*
* Private data for capturing on Linux Bluetooth devices.
*/
struct pcap_bt {
       int dev_id;             /* device ID of device we're bound to */
};

int
bt_findalldevs(pcap_if_list_t *devlistp, char *err_str)
{
       struct hci_dev_list_req *dev_list;
       struct hci_dev_req *dev_req;
       int sock;
       unsigned i;
       int ret = 0;

       sock  = socket(AF_BLUETOOTH, SOCK_RAW, BTPROTO_HCI);
       if (sock < 0)
       {
               /* if bluetooth is not supported this is not fatal*/
               if (errno == EAFNOSUPPORT)
                       return 0;
               pcapint_fmt_errmsg_for_errno(err_str, PCAP_ERRBUF_SIZE,
                   errno, "Can't open raw Bluetooth socket");
               return PCAP_ERROR;
       }

       dev_list = malloc(HCI_MAX_DEV * sizeof(*dev_req) + sizeof(*dev_list));
       if (!dev_list)
       {
               snprintf(err_str, PCAP_ERRBUF_SIZE, "Can't allocate %zu bytes for Bluetooth device list",
                       HCI_MAX_DEV * sizeof(*dev_req) + sizeof(*dev_list));
               ret = PCAP_ERROR;
               goto done;
       }

       /*
        * Zero the complete header, which is larger than dev_num because of tail
        * padding, to silence Valgrind, which overshoots validating that dev_num
        * has been set.
        * https://github.com/the-tcpdump-group/libpcap/issues/1083
        * https://bugs.kde.org/show_bug.cgi?id=448464
        */
       memset(dev_list, 0, sizeof(*dev_list));
       dev_list->dev_num = HCI_MAX_DEV;

       if (ioctl(sock, HCIGETDEVLIST, (void *) dev_list) < 0)
       {
               pcapint_fmt_errmsg_for_errno(err_str, PCAP_ERRBUF_SIZE,
                   errno, "Can't get Bluetooth device list via ioctl");
               ret = PCAP_ERROR;
               goto free;
       }

       dev_req = dev_list->dev_req;
       for (i = 0; i < dev_list->dev_num; i++, dev_req++) {
               char dev_name[20], dev_descr[40];

               snprintf(dev_name, sizeof(dev_name), BT_IFACE"%u", dev_req->dev_id);
               snprintf(dev_descr, sizeof(dev_descr), "Bluetooth adapter number %u", i);

               /*
                * Bluetooth is a wireless technology.
                * XXX - if there's the notion of associating with a
                * network, and we can determine whether the interface
                * is associated with a network, check that and set
                * the status to PCAP_IF_CONNECTION_STATUS_CONNECTED
                * or PCAP_IF_CONNECTION_STATUS_DISCONNECTED.
                */
               if (pcapint_add_dev(devlistp, dev_name, PCAP_IF_WIRELESS, dev_descr, err_str)  == NULL)
               {
                       ret = PCAP_ERROR;
                       break;
               }
       }

free:
       free(dev_list);

done:
       close(sock);
       return ret;
}

pcap_t *
bt_create(const char *device, char *ebuf, int *is_ours)
{
       const char *cp;
       char *cpend;
       long devnum;
       pcap_t *p;

       /* Does this look like a Bluetooth device? */
       cp = strrchr(device, '/');
       if (cp == NULL)
               cp = device;
       /* Does it begin with BT_IFACE? */
       if (strncmp(cp, BT_IFACE, sizeof BT_IFACE - 1) != 0) {
               /* Nope, doesn't begin with BT_IFACE */
               *is_ours = 0;
               return NULL;
       }
       /* Yes - is BT_IFACE followed by a number? */
       cp += sizeof BT_IFACE - 1;
       devnum = strtol(cp, &cpend, 10);
       if (cpend == cp || *cpend != '\0') {
               /* Not followed by a number. */
               *is_ours = 0;
               return NULL;
       }
       if (devnum < 0) {
               /* Followed by a non-valid number. */
               *is_ours = 0;
               return NULL;
       }

       /* OK, it's probably ours. */
       *is_ours = 1;

       p = PCAP_CREATE_COMMON(ebuf, struct pcap_bt);
       if (p == NULL)
               return (NULL);

       p->activate_op = bt_activate;
       return (p);
}

static int
bt_activate(pcap_t* handle)
{
       struct pcap_bt *handlep = handle->priv;
       struct sockaddr_hci addr;
       int opt;
       int             dev_id;
       struct hci_filter       flt;
       int err = PCAP_ERROR;

       /* get bt interface id */
       if (sscanf(handle->opt.device, BT_IFACE"%d", &dev_id) != 1)
       {
               snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
                       "Can't get Bluetooth device index from %s",
                        handle->opt.device);
               return PCAP_ERROR;
       }

       /*
        * Turn a negative snapshot value (invalid), a snapshot value of
        * 0 (unspecified), or a value bigger than the normal maximum
        * value, into the maximum allowed value.
        *
        * If some application really *needs* a bigger snapshot
        * length, we should just increase MAXIMUM_SNAPLEN.
        */
       if (handle->snapshot <= 0 || handle->snapshot > MAXIMUM_SNAPLEN)
               handle->snapshot = MAXIMUM_SNAPLEN;

       /* Initialize some components of the pcap structure. */
       handle->bufsize = BT_CTRL_SIZE+sizeof(pcap_bluetooth_h4_header)+handle->snapshot;
       handle->linktype = DLT_BLUETOOTH_HCI_H4_WITH_PHDR;

       handle->read_op = bt_read_linux;
       handle->inject_op = bt_inject_linux;
       handle->setfilter_op = pcapint_install_bpf_program; /* no kernel filtering */
       handle->setdirection_op = bt_setdirection_linux;
       handle->set_datalink_op = NULL; /* can't change data link type */
       handle->getnonblock_op = pcapint_getnonblock_fd;
       handle->setnonblock_op = pcapint_setnonblock_fd;
       handle->stats_op = bt_stats_linux;
       handlep->dev_id = dev_id;

       /* Create HCI socket */
       handle->fd = socket(AF_BLUETOOTH, SOCK_RAW, BTPROTO_HCI);
       if (handle->fd < 0) {
               pcapint_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
                   errno, "Can't create raw socket");
               return PCAP_ERROR;
       }

       handle->buffer = malloc(handle->bufsize);
       if (!handle->buffer) {
               pcapint_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
                   errno, "Can't allocate dump buffer");
               goto close_fail;
       }

       opt = 1;
       if (setsockopt(handle->fd, SOL_HCI, HCI_DATA_DIR, &opt, sizeof(opt)) < 0) {
               pcapint_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
                   errno, "Can't enable data direction info");
               goto close_fail;
       }

       opt = 1;
       if (setsockopt(handle->fd, SOL_HCI, HCI_TIME_STAMP, &opt, sizeof(opt)) < 0) {
               pcapint_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
                   errno, "Can't enable time stamp");
               goto close_fail;
       }

       /* Setup filter, do not call hci function to avoid dependence on
        * external libs        */
       memset(&flt, 0, sizeof(flt));
       memset((void *) &flt.type_mask, 0xff, sizeof(flt.type_mask));
       memset((void *) &flt.event_mask, 0xff, sizeof(flt.event_mask));
       if (setsockopt(handle->fd, SOL_HCI, HCI_FILTER, &flt, sizeof(flt)) < 0) {
               pcapint_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
                   errno, "Can't set filter");
               goto close_fail;
       }


       /* Bind socket to the HCI device */
       addr.hci_family = AF_BLUETOOTH;
       addr.hci_dev = handlep->dev_id;
#ifdef HAVE_STRUCT_SOCKADDR_HCI_HCI_CHANNEL
       addr.hci_channel = HCI_CHANNEL_RAW;
#endif
       if (bind(handle->fd, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
               pcapint_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
                   errno, "Can't attach to device %d", handlep->dev_id);
               goto close_fail;
       }

       if (handle->opt.rfmon) {
               /*
                * Monitor mode doesn't apply to Bluetooth devices.
                */
               err = PCAP_ERROR_RFMON_NOTSUP;
               goto close_fail;
       }

       if (handle->opt.buffer_size != 0) {
               /*
                * Set the socket buffer size to the specified value.
                */
               if (setsockopt(handle->fd, SOL_SOCKET, SO_RCVBUF,
                   &handle->opt.buffer_size,
                   sizeof(handle->opt.buffer_size)) == -1) {
                       pcapint_fmt_errmsg_for_errno(handle->errbuf,
                           errno, PCAP_ERRBUF_SIZE, "SO_RCVBUF");
                       goto close_fail;
               }
       }

       handle->selectable_fd = handle->fd;
       return 0;

close_fail:
       pcapint_cleanup_live_common(handle);
       return err;
}

static int
bt_read_linux(pcap_t *handle, int max_packets _U_, pcap_handler callback, u_char *user)
{
       struct cmsghdr *cmsg;
       struct msghdr msg;
       struct iovec  iv;
       ssize_t ret;
       struct pcap_pkthdr pkth;
       pcap_bluetooth_h4_header* bthdr;
       u_char *pktd;
       int in = 0;

       pktd = (u_char *)handle->buffer + BT_CTRL_SIZE;
       bthdr = (pcap_bluetooth_h4_header*)(void *)pktd;
       iv.iov_base = pktd + sizeof(pcap_bluetooth_h4_header);
       iv.iov_len  = handle->snapshot;

       memset(&msg, 0, sizeof(msg));
       msg.msg_iov = &iv;
       msg.msg_iovlen = 1;
       msg.msg_control = handle->buffer;
       msg.msg_controllen = BT_CTRL_SIZE;

       /* ignore interrupt system call error */
       do {
               if (handle->break_loop)
               {
                       handle->break_loop = 0;
                       return PCAP_ERROR_BREAK;
               }
               ret = recvmsg(handle->fd, &msg, 0);
       } while ((ret == -1) && (errno == EINTR));

       if (ret < 0) {
               if (errno == EAGAIN || errno == EWOULDBLOCK) {
                       /* Nonblocking mode, no data */
                       return 0;
               }
               pcapint_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
                   errno, "Can't receive packet");
               return PCAP_ERROR;
       }

       pkth.caplen = (bpf_u_int32)ret;

       /* get direction and timestamp*/
       cmsg = CMSG_FIRSTHDR(&msg);
       while (cmsg) {
               switch (cmsg->cmsg_type) {
                       case HCI_CMSG_DIR:
                               memcpy(&in, CMSG_DATA(cmsg), sizeof in);
                               break;
                       case HCI_CMSG_TSTAMP:
                               memcpy(&pkth.ts, CMSG_DATA(cmsg),
                                       sizeof pkth.ts);
                               break;
               }
               // for musl libc CMSG_NXTHDR()
DIAG_OFF_SIGN_COMPARE
               cmsg = CMSG_NXTHDR(&msg, cmsg);
DIAG_ON_SIGN_COMPARE
       }
       switch (handle->direction) {

       case PCAP_D_IN:
               if (!in)
                       return 0;
               break;

       case PCAP_D_OUT:
               if (in)
                       return 0;
               break;

       default:
               break;
       }

       bthdr->direction = htonl(in != 0);
       pkth.caplen+=sizeof(pcap_bluetooth_h4_header);
       pkth.len = pkth.caplen;
       if (handle->fcode.bf_insns == NULL ||
           pcapint_filter(handle->fcode.bf_insns, pktd, pkth.len, pkth.caplen)) {
               callback(user, &pkth, pktd);
               return 1;
       }
       return 0;       /* didn't pass filter */
}

static int
bt_inject_linux(pcap_t *handle, const void *buf _U_, int size _U_)
{
       snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
           "Packet injection is not supported on Bluetooth devices");
       return (-1);
}


static int
bt_stats_linux(pcap_t *handle, struct pcap_stat *stats)
{
       struct pcap_bt *handlep = handle->priv;
       int ret;
       struct hci_dev_info dev_info;
       struct hci_dev_stats * s = &dev_info.stat;
       dev_info.dev_id = handlep->dev_id;

       /* ignore eintr */
       do {
               ret = ioctl(handle->fd, HCIGETDEVINFO, (void *)&dev_info);
       } while ((ret == -1) && (errno == EINTR));

       if (ret < 0) {
               pcapint_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
                   errno, "Can't get stats via ioctl");
               return (-1);

       }

       /* we receive both rx and tx frames, so cumulate all stats */
       stats->ps_recv = s->evt_rx + s->acl_rx + s->sco_rx + s->cmd_tx +
               s->acl_tx +s->sco_tx;
       stats->ps_drop = s->err_rx + s->err_tx;
       stats->ps_ifdrop = 0;
       return 0;
}

static int
bt_setdirection_linux(pcap_t *p, pcap_direction_t d)
{
       /*
        * It's guaranteed, at this point, that d is a valid
        * direction value.
        */
       p->direction = d;
       return 0;
}

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