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l2cap.c
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l2cap.c
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/* l2cap.c - L2CAP handling */
/*
* Copyright (c) 2015-2016 Intel Corporation
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <zephyr.h>
#include <string.h>
#include <errno.h>
#include <atomic.h>
#include <misc/byteorder.h>
#include <misc/util.h>
#include <bluetooth/hci.h>
#include <bluetooth/bluetooth.h>
#include <bluetooth/conn.h>
#include <bluetooth/hci_driver.h>
#define BT_DBG_ENABLED IS_ENABLED(CONFIG_BT_DEBUG_L2CAP)
#define LOG_MODULE_NAME bt_l2cap
#include "common/log.h"
#include "hci_core.h"
#include "conn_internal.h"
#include "l2cap_internal.h"
#define LE_CHAN_RTX(_w) CONTAINER_OF(_w, struct bt_l2cap_le_chan, chan.rtx_work)
#define L2CAP_LE_MIN_MTU 23
#if defined(CONFIG_BT_HCI_ACL_FLOW_CONTROL)
#define L2CAP_LE_MAX_CREDITS (CONFIG_BT_ACL_RX_COUNT - 1)
#else
#define L2CAP_LE_MAX_CREDITS (CONFIG_BT_RX_BUF_COUNT - 1)
#endif
#define L2CAP_LE_CID_DYN_START 0x0040
#define L2CAP_LE_CID_DYN_END 0x007f
#define L2CAP_LE_CID_IS_DYN(_cid) \
(_cid >= L2CAP_LE_CID_DYN_START && _cid <= L2CAP_LE_CID_DYN_END)
#define L2CAP_LE_PSM_FIXED_START 0x0001
#define L2CAP_LE_PSM_FIXED_END 0x007f
#define L2CAP_LE_PSM_DYN_START 0x0080
#define L2CAP_LE_PSM_DYN_END 0x00ff
#define L2CAP_CONN_TIMEOUT K_SECONDS(40)
#define L2CAP_DISC_TIMEOUT K_SECONDS(2)
/* Linker-defined symbols bound to the bt_l2cap_fixed_chan structs */
extern const struct bt_l2cap_fixed_chan _bt_channels_start[];
extern const struct bt_l2cap_fixed_chan _bt_channels_end[];
#if defined(CONFIG_BT_L2CAP_DYNAMIC_CHANNEL)
/* Size of MTU is based on the maximum amount of data the buffer can hold
* excluding ACL and driver headers.
*/
#define L2CAP_MAX_LE_MPS BT_L2CAP_RX_MTU
/* For now use MPS - SDU length to disable segmentation */
#define L2CAP_MAX_LE_MTU (L2CAP_MAX_LE_MPS - 2)
#define l2cap_lookup_ident(conn, ident) __l2cap_lookup_ident(conn, ident, false)
#define l2cap_remove_ident(conn, ident) __l2cap_lookup_ident(conn, ident, true)
static sys_slist_t servers;
#endif /* CONFIG_BT_L2CAP_DYNAMIC_CHANNEL */
/* L2CAP signalling channel specific context */
struct bt_l2cap {
/* The channel this context is associated with */
struct bt_l2cap_le_chan chan;
};
static struct bt_l2cap bt_l2cap_pool[CONFIG_BT_MAX_CONN];
static u8_t get_ident(void)
{
static u8_t ident;
ident++;
/* handle integer overflow (0 is not valid) */
if (!ident) {
ident++;
}
return ident;
}
#if defined(CONFIG_BT_L2CAP_DYNAMIC_CHANNEL)
static struct bt_l2cap_le_chan *l2cap_chan_alloc_cid(struct bt_conn *conn,
struct bt_l2cap_chan *chan)
{
struct bt_l2cap_le_chan *ch = BT_L2CAP_LE_CHAN(chan);
u16_t cid;
/*
* No action needed if there's already a CID allocated, e.g. in
* the case of a fixed channel.
*/
if (ch && ch->rx.cid > 0) {
return ch;
}
for (cid = L2CAP_LE_CID_DYN_START; cid <= L2CAP_LE_CID_DYN_END; cid++) {
if (ch && !bt_l2cap_le_lookup_rx_cid(conn, cid)) {
ch->rx.cid = cid;
return ch;
}
}
return NULL;
}
static struct bt_l2cap_le_chan *
__l2cap_lookup_ident(struct bt_conn *conn, u16_t ident, bool remove)
{
struct bt_l2cap_chan *chan;
sys_snode_t *prev = NULL;
SYS_SLIST_FOR_EACH_CONTAINER(&conn->channels, chan, node) {
if (chan->ident == ident) {
if (remove) {
sys_slist_remove(&conn->channels, prev,
&chan->node);
}
return BT_L2CAP_LE_CHAN(chan);
}
prev = &chan->node;
}
return NULL;
}
#endif /* CONFIG_BT_L2CAP_DYNAMIC_CHANNEL */
void bt_l2cap_chan_remove(struct bt_conn *conn, struct bt_l2cap_chan *ch)
{
struct bt_l2cap_chan *chan;
sys_snode_t *prev = NULL;
SYS_SLIST_FOR_EACH_CONTAINER(&conn->channels, chan, node) {
if (chan == ch) {
sys_slist_remove(&conn->channels, prev, &chan->node);
return;
}
prev = &chan->node;
}
}
const char *bt_l2cap_chan_state_str(bt_l2cap_chan_state_t state)
{
switch (state) {
case BT_L2CAP_DISCONNECTED:
return "disconnected";
case BT_L2CAP_CONNECT:
return "connect";
case BT_L2CAP_CONFIG:
return "config";
case BT_L2CAP_CONNECTED:
return "connected";
case BT_L2CAP_DISCONNECT:
return "disconnect";
default:
return "unknown";
}
}
#if defined(CONFIG_BT_L2CAP_DYNAMIC_CHANNEL)
#if defined(CONFIG_BT_DEBUG_L2CAP)
void bt_l2cap_chan_set_state_debug(struct bt_l2cap_chan *chan,
bt_l2cap_chan_state_t state,
const char *func, int line)
{
BT_DBG("chan %p psm 0x%04x %s -> %s", chan, chan->psm,
bt_l2cap_chan_state_str(chan->state),
bt_l2cap_chan_state_str(state));
/* check transitions validness */
switch (state) {
case BT_L2CAP_DISCONNECTED:
/* regardless of old state always allows this state */
break;
case BT_L2CAP_CONNECT:
if (chan->state != BT_L2CAP_DISCONNECTED) {
BT_WARN("%s()%d: invalid transition", func, line);
}
break;
case BT_L2CAP_CONFIG:
if (chan->state != BT_L2CAP_CONNECT) {
BT_WARN("%s()%d: invalid transition", func, line);
}
break;
case BT_L2CAP_CONNECTED:
if (chan->state != BT_L2CAP_CONFIG &&
chan->state != BT_L2CAP_CONNECT) {
BT_WARN("%s()%d: invalid transition", func, line);
}
break;
case BT_L2CAP_DISCONNECT:
if (chan->state != BT_L2CAP_CONFIG &&
chan->state != BT_L2CAP_CONNECTED) {
BT_WARN("%s()%d: invalid transition", func, line);
}
break;
default:
BT_ERR("%s()%d: unknown (%u) state was set", func, line, state);
return;
}
chan->state = state;
}
#else
void bt_l2cap_chan_set_state(struct bt_l2cap_chan *chan,
bt_l2cap_chan_state_t state)
{
chan->state = state;
}
#endif /* CONFIG_BT_DEBUG_L2CAP */
#endif /* CONFIG_BT_L2CAP_DYNAMIC_CHANNEL */
void bt_l2cap_chan_del(struct bt_l2cap_chan *chan)
{
BT_DBG("conn %p chan %p", chan->conn, chan);
if (!chan->conn) {
goto destroy;
}
if (chan->ops->disconnected) {
chan->ops->disconnected(chan);
}
chan->conn = NULL;
destroy:
#if defined(CONFIG_BT_L2CAP_DYNAMIC_CHANNEL)
/* Reset internal members of common channel */
bt_l2cap_chan_set_state(chan, BT_L2CAP_DISCONNECTED);
chan->psm = 0U;
#endif
if (chan->destroy) {
chan->destroy(chan);
}
}
static void l2cap_rtx_timeout(struct k_work *work)
{
struct bt_l2cap_le_chan *chan = LE_CHAN_RTX(work);
BT_ERR("chan %p timeout", chan);
bt_l2cap_chan_remove(chan->chan.conn, &chan->chan);
bt_l2cap_chan_del(&chan->chan);
}
void bt_l2cap_chan_add(struct bt_conn *conn, struct bt_l2cap_chan *chan,
bt_l2cap_chan_destroy_t destroy)
{
/* Attach channel to the connection */
sys_slist_append(&conn->channels, &chan->node);
chan->conn = conn;
chan->destroy = destroy;
BT_DBG("conn %p chan %p", conn, chan);
}
static bool l2cap_chan_add(struct bt_conn *conn, struct bt_l2cap_chan *chan,
bt_l2cap_chan_destroy_t destroy)
{
struct bt_l2cap_le_chan *ch;
#if defined(CONFIG_BT_L2CAP_DYNAMIC_CHANNEL)
ch = l2cap_chan_alloc_cid(conn, chan);
#else
ch = BT_L2CAP_LE_CHAN(chan);
#endif
if (!ch) {
BT_ERR("Unable to allocate L2CAP CID");
return false;
}
k_delayed_work_init(&chan->rtx_work, l2cap_rtx_timeout);
bt_l2cap_chan_add(conn, chan, destroy);
if (IS_ENABLED(CONFIG_BT_L2CAP_DYNAMIC_CHANNEL) &&
L2CAP_LE_CID_IS_DYN(ch->rx.cid)) {
bt_l2cap_chan_set_state(chan, BT_L2CAP_CONNECT);
}
return true;
}
void bt_l2cap_connected(struct bt_conn *conn)
{
const struct bt_l2cap_fixed_chan *fchan;
struct bt_l2cap_chan *chan;
if (IS_ENABLED(CONFIG_BT_BREDR) &&
conn->type == BT_CONN_TYPE_BR) {
bt_l2cap_br_connected(conn);
return;
}
for (fchan = _bt_channels_start; fchan < _bt_channels_end; fchan++) {
struct bt_l2cap_le_chan *ch;
if (fchan->accept(conn, &chan) < 0) {
continue;
}
ch = BT_L2CAP_LE_CHAN(chan);
/* Fill up remaining fixed channel context attached in
* fchan->accept()
*/
ch->rx.cid = fchan->cid;
ch->tx.cid = fchan->cid;
if (!l2cap_chan_add(conn, chan, NULL)) {
return;
}
if (chan->ops->connected) {
chan->ops->connected(chan);
}
}
}
void bt_l2cap_disconnected(struct bt_conn *conn)
{
struct bt_l2cap_chan *chan, *next;
SYS_SLIST_FOR_EACH_CONTAINER_SAFE(&conn->channels, chan, next, node) {
bt_l2cap_chan_del(chan);
}
}
static struct net_buf *l2cap_create_le_sig_pdu(struct net_buf *buf,
u8_t code, u8_t ident,
u16_t len)
{
struct bt_l2cap_sig_hdr *hdr;
buf = bt_l2cap_create_pdu(NULL, 0);
hdr = net_buf_add(buf, sizeof(*hdr));
hdr->code = code;
hdr->ident = ident;
hdr->len = sys_cpu_to_le16(len);
return buf;
}
#if defined(CONFIG_BT_L2CAP_DYNAMIC_CHANNEL)
static void l2cap_chan_send_req(struct bt_l2cap_le_chan *chan,
struct net_buf *buf, s32_t timeout)
{
/* BLUETOOTH SPECIFICATION Version 4.2 [Vol 3, Part A] page 126:
*
* The value of this timer is implementation-dependent but the minimum
* initial value is 1 second and the maximum initial value is 60
* seconds. One RTX timer shall exist for each outstanding signaling
* request, including each Echo Request. The timer disappears on the
* final expiration, when the response is received, or the physical
* link is lost.
*/
if (timeout) {
k_delayed_work_submit(&chan->chan.rtx_work, timeout);
} else {
k_delayed_work_cancel(&chan->chan.rtx_work);
}
bt_l2cap_send(chan->chan.conn, BT_L2CAP_CID_LE_SIG, buf);
}
static int l2cap_le_conn_req(struct bt_l2cap_le_chan *ch)
{
struct net_buf *buf;
struct bt_l2cap_le_conn_req *req;
ch->chan.ident = get_ident();
buf = l2cap_create_le_sig_pdu(NULL, BT_L2CAP_LE_CONN_REQ,
ch->chan.ident, sizeof(*req));
req = net_buf_add(buf, sizeof(*req));
req->psm = sys_cpu_to_le16(ch->chan.psm);
req->scid = sys_cpu_to_le16(ch->rx.cid);
req->mtu = sys_cpu_to_le16(ch->rx.mtu);
req->mps = sys_cpu_to_le16(ch->rx.mps);
req->credits = sys_cpu_to_le16(ch->rx.init_credits);
l2cap_chan_send_req(ch, buf, L2CAP_CONN_TIMEOUT);
return 0;
}
static void l2cap_le_encrypt_change(struct bt_l2cap_chan *chan, u8_t status)
{
/* Skip channels already connected or with a pending request */
if (chan->state != BT_L2CAP_CONNECT || chan->ident) {
return;
}
if (status) {
bt_l2cap_chan_remove(chan->conn, chan);
bt_l2cap_chan_del(chan);
return;
}
/* Retry to connect */
l2cap_le_conn_req(BT_L2CAP_LE_CHAN(chan));
}
#endif /* CONFIG_BT_L2CAP_DYNAMIC_CHANNEL */
void bt_l2cap_encrypt_change(struct bt_conn *conn, u8_t hci_status)
{
struct bt_l2cap_chan *chan;
if (IS_ENABLED(CONFIG_BT_BREDR) &&
conn->type == BT_CONN_TYPE_BR) {
l2cap_br_encrypt_change(conn, hci_status);
return;
}
SYS_SLIST_FOR_EACH_CONTAINER(&conn->channels, chan, node) {
#if defined(CONFIG_BT_L2CAP_DYNAMIC_CHANNEL)
l2cap_le_encrypt_change(chan, hci_status);
#endif
if (chan->ops->encrypt_change) {
chan->ops->encrypt_change(chan, hci_status);
}
}
}
struct net_buf *bt_l2cap_create_pdu(struct net_buf_pool *pool, size_t reserve)
{
return bt_conn_create_pdu(pool, sizeof(struct bt_l2cap_hdr) + reserve);
}
void bt_l2cap_send_cb(struct bt_conn *conn, u16_t cid, struct net_buf *buf,
bt_conn_tx_cb_t cb, void *user_data)
{
struct bt_l2cap_hdr *hdr;
BT_DBG("conn %p cid %u len %zu", conn, cid, net_buf_frags_len(buf));
hdr = net_buf_push(buf, sizeof(*hdr));
hdr->len = sys_cpu_to_le16(buf->len - sizeof(*hdr));
hdr->cid = sys_cpu_to_le16(cid);
bt_conn_send_cb(conn, buf, cb, user_data);
}
static void l2cap_send_reject(struct bt_conn *conn, u8_t ident,
u16_t reason, void *data, u8_t data_len)
{
struct bt_l2cap_cmd_reject *rej;
struct net_buf *buf;
buf = l2cap_create_le_sig_pdu(NULL, BT_L2CAP_CMD_REJECT, ident,
sizeof(*rej) + data_len);
rej = net_buf_add(buf, sizeof(*rej));
rej->reason = sys_cpu_to_le16(reason);
if (data) {
net_buf_add_mem(buf, data, data_len);
}
bt_l2cap_send(conn, BT_L2CAP_CID_LE_SIG, buf);
}
static void le_conn_param_rsp(struct bt_l2cap *l2cap, struct net_buf *buf)
{
struct bt_l2cap_conn_param_rsp *rsp = (void *)buf->data;
if (buf->len < sizeof(*rsp)) {
BT_ERR("Too small LE conn param rsp");
return;
}
BT_DBG("LE conn param rsp result %u", sys_le16_to_cpu(rsp->result));
}
#if defined(CONFIG_BT_CENTRAL)
static void le_conn_param_update_req(struct bt_l2cap *l2cap, u8_t ident,
struct net_buf *buf)
{
struct bt_conn *conn = l2cap->chan.chan.conn;
struct bt_le_conn_param param;
struct bt_l2cap_conn_param_rsp *rsp;
struct bt_l2cap_conn_param_req *req = (void *)buf->data;
bool accepted;
if (buf->len < sizeof(*req)) {
BT_ERR("Too small LE conn update param req");
return;
}
if (conn->role != BT_HCI_ROLE_MASTER) {
l2cap_send_reject(conn, ident, BT_L2CAP_REJ_NOT_UNDERSTOOD,
NULL, 0);
return;
}
param.interval_min = sys_le16_to_cpu(req->min_interval);
param.interval_max = sys_le16_to_cpu(req->max_interval);
param.latency = sys_le16_to_cpu(req->latency);
param.timeout = sys_le16_to_cpu(req->timeout);
BT_DBG("min 0x%04x max 0x%04x latency: 0x%04x timeout: 0x%04x",
param.interval_min, param.interval_max, param.latency,
param.timeout);
buf = l2cap_create_le_sig_pdu(buf, BT_L2CAP_CONN_PARAM_RSP, ident,
sizeof(*rsp));
accepted = le_param_req(conn, ¶m);
rsp = net_buf_add(buf, sizeof(*rsp));
if (accepted) {
rsp->result = sys_cpu_to_le16(BT_L2CAP_CONN_PARAM_ACCEPTED);
} else {
rsp->result = sys_cpu_to_le16(BT_L2CAP_CONN_PARAM_REJECTED);
}
bt_l2cap_send(conn, BT_L2CAP_CID_LE_SIG, buf);
if (accepted) {
bt_conn_le_conn_update(conn, ¶m);
}
}
#endif /* CONFIG_BT_CENTRAL */
struct bt_l2cap_chan *bt_l2cap_le_lookup_tx_cid(struct bt_conn *conn,
u16_t cid)
{
struct bt_l2cap_chan *chan;
SYS_SLIST_FOR_EACH_CONTAINER(&conn->channels, chan, node) {
if (BT_L2CAP_LE_CHAN(chan)->tx.cid == cid) {
return chan;
}
}
return NULL;
}
struct bt_l2cap_chan *bt_l2cap_le_lookup_rx_cid(struct bt_conn *conn,
u16_t cid)
{
struct bt_l2cap_chan *chan;
SYS_SLIST_FOR_EACH_CONTAINER(&conn->channels, chan, node) {
if (BT_L2CAP_LE_CHAN(chan)->rx.cid == cid) {
return chan;
}
}
return NULL;
}
#if defined(CONFIG_BT_L2CAP_DYNAMIC_CHANNEL)
static struct bt_l2cap_server *l2cap_server_lookup_psm(u16_t psm)
{
struct bt_l2cap_server *server;
SYS_SLIST_FOR_EACH_CONTAINER(&servers, server, node) {
if (server->psm == psm) {
return server;
}
}
return NULL;
}
int bt_l2cap_server_register(struct bt_l2cap_server *server)
{
if (!server->accept) {
return -EINVAL;
}
if (server->psm) {
if (server->psm < L2CAP_LE_PSM_FIXED_START ||
server->psm > L2CAP_LE_PSM_DYN_END) {
return -EINVAL;
}
/* Check if given PSM is already in use */
if (l2cap_server_lookup_psm(server->psm)) {
BT_DBG("PSM already registered");
return -EADDRINUSE;
}
} else {
u16_t psm;
for (psm = L2CAP_LE_PSM_DYN_START;
psm <= L2CAP_LE_PSM_DYN_END; psm++) {
if (!l2cap_server_lookup_psm(psm)) {
break;
}
}
if (psm > L2CAP_LE_PSM_DYN_END) {
BT_WARN("No free dynamic PSMs available");
return -EADDRNOTAVAIL;
}
BT_DBG("Allocated PSM 0x%04x for new server", psm);
server->psm = psm;
}
if (server->sec_level > BT_SECURITY_FIPS) {
return -EINVAL;
} else if (server->sec_level < BT_SECURITY_LOW) {
/* Level 0 is only applicable for BR/EDR */
server->sec_level = BT_SECURITY_LOW;
}
BT_DBG("PSM 0x%04x", server->psm);
sys_slist_append(&servers, &server->node);
return 0;
}
static void l2cap_chan_rx_init(struct bt_l2cap_le_chan *chan)
{
BT_DBG("chan %p", chan);
/* Use existing MTU if defined */
if (!chan->rx.mtu) {
chan->rx.mtu = L2CAP_MAX_LE_MTU;
}
/* Use existing credits if defined */
if (!chan->rx.init_credits) {
if (chan->chan.ops->alloc_buf) {
/* Auto tune credits to receive a full packet */
chan->rx.init_credits = (chan->rx.mtu +
(L2CAP_MAX_LE_MPS - 1)) /
L2CAP_MAX_LE_MPS;
} else {
chan->rx.init_credits = L2CAP_LE_MAX_CREDITS;
}
}
/* MPS shall not be bigger than MTU + 2 as the remaining bytes cannot
* be used.
*/
chan->rx.mps = MIN(chan->rx.mtu + 2, L2CAP_MAX_LE_MPS);
k_sem_init(&chan->rx.credits, 0, UINT_MAX);
if (BT_DBG_ENABLED &&
chan->rx.init_credits * chan->rx.mps < chan->rx.mtu + 2) {
BT_WARN("Not enough credits for a full packet");
}
}
static void l2cap_chan_tx_init(struct bt_l2cap_le_chan *chan)
{
BT_DBG("chan %p", chan);
(void)memset(&chan->tx, 0, sizeof(chan->tx));
k_sem_init(&chan->tx.credits, 0, UINT_MAX);
k_fifo_init(&chan->tx_queue);
}
static void l2cap_chan_tx_give_credits(struct bt_l2cap_le_chan *chan,
u16_t credits)
{
BT_DBG("chan %p credits %u", chan, credits);
while (credits--) {
k_sem_give(&chan->tx.credits);
}
}
static void l2cap_chan_rx_give_credits(struct bt_l2cap_le_chan *chan,
u16_t credits)
{
BT_DBG("chan %p credits %u", chan, credits);
while (credits--) {
k_sem_give(&chan->rx.credits);
}
}
static void l2cap_chan_destroy(struct bt_l2cap_chan *chan)
{
struct bt_l2cap_le_chan *ch = BT_L2CAP_LE_CHAN(chan);
struct net_buf *buf;
BT_DBG("chan %p cid 0x%04x", ch, ch->rx.cid);
/* Cancel ongoing work */
k_delayed_work_cancel(&chan->rtx_work);
/* Remove buffers on the TX queue */
while ((buf = net_buf_get(&ch->tx_queue, K_NO_WAIT))) {
net_buf_unref(buf);
}
/* Destroy segmented SDU if it exists */
if (ch->_sdu) {
net_buf_unref(ch->_sdu);
ch->_sdu = NULL;
ch->_sdu_len = 0U;
}
}
static u16_t le_err_to_result(int err)
{
switch (err) {
case -ENOMEM:
return BT_L2CAP_LE_ERR_NO_RESOURCES;
case -EACCES:
return BT_L2CAP_LE_ERR_AUTHORIZATION;
case -EPERM:
return BT_L2CAP_LE_ERR_KEY_SIZE;
case -ENOTSUP:
/* This handle the cases where a fixed channel is registered but
* for some reason (e.g. controller not suporting a feature)
* cannot be used.
*/
return BT_L2CAP_LE_ERR_PSM_NOT_SUPP;
default:
return BT_L2CAP_LE_ERR_UNACCEPT_PARAMS;
}
}
static void le_conn_req(struct bt_l2cap *l2cap, u8_t ident,
struct net_buf *buf)
{
struct bt_conn *conn = l2cap->chan.chan.conn;
struct bt_l2cap_chan *chan;
struct bt_l2cap_server *server;
struct bt_l2cap_le_conn_req *req = (void *)buf->data;
struct bt_l2cap_le_conn_rsp *rsp;
u16_t psm, scid, mtu, mps, credits;
int err;
if (buf->len < sizeof(*req)) {
BT_ERR("Too small LE conn req packet size");
return;
}
psm = sys_le16_to_cpu(req->psm);
scid = sys_le16_to_cpu(req->scid);
mtu = sys_le16_to_cpu(req->mtu);
mps = sys_le16_to_cpu(req->mps);
credits = sys_le16_to_cpu(req->credits);
BT_DBG("psm 0x%02x scid 0x%04x mtu %u mps %u credits %u", psm, scid,
mtu, mps, credits);
if (mtu < L2CAP_LE_MIN_MTU || mps < L2CAP_LE_MIN_MTU) {
BT_ERR("Invalid LE-Conn Req params");
return;
}
buf = l2cap_create_le_sig_pdu(buf, BT_L2CAP_LE_CONN_RSP, ident,
sizeof(*rsp));
rsp = net_buf_add(buf, sizeof(*rsp));
(void)memset(rsp, 0, sizeof(*rsp));
/* Check if there is a server registered */
server = l2cap_server_lookup_psm(psm);
if (!server) {
rsp->result = sys_cpu_to_le16(BT_L2CAP_LE_ERR_PSM_NOT_SUPP);
goto rsp;
}
/* Check if connection has minimum required security level */
if (conn->sec_level < server->sec_level) {
rsp->result = sys_cpu_to_le16(BT_L2CAP_LE_ERR_AUTHENTICATION);
goto rsp;
}
if (!L2CAP_LE_CID_IS_DYN(scid)) {
rsp->result = sys_cpu_to_le16(BT_L2CAP_LE_ERR_INVALID_SCID);
goto rsp;
}
chan = bt_l2cap_le_lookup_tx_cid(conn, scid);
if (chan) {
rsp->result = sys_cpu_to_le16(BT_L2CAP_LE_ERR_SCID_IN_USE);
goto rsp;
}
/* Request server to accept the new connection and allocate the
* channel.
*/
err = server->accept(conn, &chan);
if (err < 0) {
rsp->result = sys_cpu_to_le16(le_err_to_result(err));
goto rsp;
}
chan->required_sec_level = server->sec_level;
if (l2cap_chan_add(conn, chan, l2cap_chan_destroy)) {
struct bt_l2cap_le_chan *ch = BT_L2CAP_LE_CHAN(chan);
/* Init TX parameters */
l2cap_chan_tx_init(ch);
ch->tx.cid = scid;
ch->tx.mps = mps;
ch->tx.mtu = mtu;
ch->tx.init_credits = credits;
l2cap_chan_tx_give_credits(ch, credits);
/* Init RX parameters */
l2cap_chan_rx_init(ch);
l2cap_chan_rx_give_credits(ch, ch->rx.init_credits);
/* Set channel PSM */
chan->psm = server->psm;
/* Update state */
bt_l2cap_chan_set_state(chan, BT_L2CAP_CONNECTED);
if (chan->ops->connected) {
chan->ops->connected(chan);
}
/* Prepare response protocol data */
rsp->dcid = sys_cpu_to_le16(ch->rx.cid);
rsp->mps = sys_cpu_to_le16(ch->rx.mps);
rsp->mtu = sys_cpu_to_le16(ch->rx.mtu);
rsp->credits = sys_cpu_to_le16(ch->rx.init_credits);
rsp->result = BT_L2CAP_LE_SUCCESS;
} else {
rsp->result = sys_cpu_to_le16(BT_L2CAP_LE_ERR_NO_RESOURCES);
}
rsp:
bt_l2cap_send(conn, BT_L2CAP_CID_LE_SIG, buf);
}
static struct bt_l2cap_le_chan *l2cap_remove_tx_cid(struct bt_conn *conn,
u16_t cid)
{
struct bt_l2cap_chan *chan;
sys_snode_t *prev = NULL;
/* Protect fixed channels against accidental removal */
if (!L2CAP_LE_CID_IS_DYN(cid)) {
return NULL;
}
SYS_SLIST_FOR_EACH_CONTAINER(&conn->channels, chan, node) {
if (BT_L2CAP_LE_CHAN(chan)->rx.cid == cid) {
sys_slist_remove(&conn->channels, prev, &chan->node);
return BT_L2CAP_LE_CHAN(chan);
}
prev = &chan->node;
}
return NULL;
}
static void le_disconn_req(struct bt_l2cap *l2cap, u8_t ident,
struct net_buf *buf)
{
struct bt_conn *conn = l2cap->chan.chan.conn;
struct bt_l2cap_le_chan *chan;
struct bt_l2cap_disconn_req *req = (void *)buf->data;
struct bt_l2cap_disconn_rsp *rsp;
u16_t scid;
if (buf->len < sizeof(*req)) {
BT_ERR("Too small LE conn req packet size");
return;
}
scid = sys_le16_to_cpu(req->scid);
BT_DBG("scid 0x%04x dcid 0x%04x", scid, sys_le16_to_cpu(req->dcid));
chan = l2cap_remove_tx_cid(conn, scid);
if (!chan) {
struct bt_l2cap_cmd_reject_cid_data data;
data.scid = req->scid;
data.dcid = req->dcid;
l2cap_send_reject(conn, ident, BT_L2CAP_REJ_INVALID_CID, &data,
sizeof(data));
return;
}
buf = l2cap_create_le_sig_pdu(buf, BT_L2CAP_DISCONN_RSP, ident,
sizeof(*rsp));
rsp = net_buf_add(buf, sizeof(*rsp));
rsp->dcid = sys_cpu_to_le16(chan->rx.cid);
rsp->scid = sys_cpu_to_le16(chan->tx.cid);
bt_l2cap_chan_del(&chan->chan);
bt_l2cap_send(conn, BT_L2CAP_CID_LE_SIG, buf);
}
static int l2cap_change_security(struct bt_l2cap_le_chan *chan, u16_t err)
{
switch (err) {
case BT_L2CAP_LE_ERR_ENCRYPTION:
if (chan->chan.required_sec_level >= BT_SECURITY_MEDIUM) {
return -EALREADY;
}
chan->chan.required_sec_level = BT_SECURITY_MEDIUM;
break;
case BT_L2CAP_LE_ERR_AUTHENTICATION:
if (chan->chan.required_sec_level < BT_SECURITY_MEDIUM) {
chan->chan.required_sec_level = BT_SECURITY_MEDIUM;
} else if (chan->chan.required_sec_level < BT_SECURITY_HIGH) {
chan->chan.required_sec_level = BT_SECURITY_HIGH;
} else if (chan->chan.required_sec_level < BT_SECURITY_FIPS) {
chan->chan.required_sec_level = BT_SECURITY_FIPS;
} else {
return -EALREADY;
}
break;
default:
return -EINVAL;
}
return bt_conn_security(chan->chan.conn, chan->chan.required_sec_level);
}
static void le_conn_rsp(struct bt_l2cap *l2cap, u8_t ident,
struct net_buf *buf)
{
struct bt_conn *conn = l2cap->chan.chan.conn;
struct bt_l2cap_le_chan *chan;
struct bt_l2cap_le_conn_rsp *rsp = (void *)buf->data;
u16_t dcid, mtu, mps, credits, result;
if (buf->len < sizeof(*rsp)) {
BT_ERR("Too small LE conn rsp packet size");
return;
}
dcid = sys_le16_to_cpu(rsp->dcid);
mtu = sys_le16_to_cpu(rsp->mtu);
mps = sys_le16_to_cpu(rsp->mps);
credits = sys_le16_to_cpu(rsp->credits);
result = sys_le16_to_cpu(rsp->result);
BT_DBG("dcid 0x%04x mtu %u mps %u credits %u result 0x%04x", dcid,
mtu, mps, credits, result);
/* Keep the channel in case of security errors */
if (result == BT_L2CAP_LE_SUCCESS ||
result == BT_L2CAP_LE_ERR_AUTHENTICATION ||
result == BT_L2CAP_LE_ERR_ENCRYPTION) {
chan = l2cap_lookup_ident(conn, ident);
} else {
chan = l2cap_remove_ident(conn, ident);
}
if (!chan) {
BT_ERR("Cannot find channel for ident %u", ident);
return;
}
/* Cancel RTX work */
k_delayed_work_cancel(&chan->chan.rtx_work);
/* Reset ident since it got a response */
chan->chan.ident = 0U;
switch (result) {
case BT_L2CAP_LE_SUCCESS:
chan->tx.cid = dcid;
chan->tx.mtu = mtu;
chan->tx.mps = mps;
/* Update state */
bt_l2cap_chan_set_state(&chan->chan, BT_L2CAP_CONNECTED);
if (chan->chan.ops->connected) {
chan->chan.ops->connected(&chan->chan);
}
/* Give credits */
l2cap_chan_tx_give_credits(chan, credits);
l2cap_chan_rx_give_credits(chan, chan->rx.init_credits);