From: Nathan Holstein <nathan@xxxxxxxxxxxxxxxxxxx>
When negotiating the configuration of an L2CAP socket, the remote may reject
the initial configuration that was sent. This patch adds allows selecting
differing configuration values.
Signed-off-by: Nathan Holstein <nathan@xxxxxxxxxxxxxxxxxxx>
---
net/bluetooth/l2cap.c | 106 ++++++++++++++++++++++++++++++++++++++++++++----
1 files changed, 97 insertions(+), 9 deletions(-)
diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c
index 228f7f0..b7c2e94 100644
--- a/net/bluetooth/l2cap.c
+++ b/net/bluetooth/l2cap.c
@@ -2012,6 +2012,70 @@ static int l2cap_parse_conf_req(struct sock *sk, void *data)
return ptr - data;
}
+static inline int l2cap_parse_conf_rsp(struct sock *sk, void *rsp, int len, void *_req, u16 *result)
+{
+ struct l2cap_pinfo *pi = l2cap_pi(sk);
+ struct l2cap_conf_req *req = _req;
+ void *ptr = req->data;
+ int type, hint, olen;
+ unsigned long val;
+ struct l2cap_conf_rfc rfc;
+
+ BT_DBG("sk %p, rsp %p, len %d, req %p", sk, rsp, len, _req);
+
+ while (len >= L2CAP_CONF_OPT_SIZE) {
+ len -= l2cap_get_conf_opt(&rsp, &type, &olen, &val);
+
+ hint = type & L2CAP_CONF_HINT;
+ type &= 0x7f;
+
+ switch (type) {
+ case L2CAP_CONF_MTU:
+ if (val < L2CAP_DEFAULT_MIN_MTU)
+ {
+ *result = L2CAP_CONF_UNACCEPT;
+ pi->omtu = L2CAP_DEFAULT_MIN_MTU;
+ }
+ else
+ pi->omtu = val;
+ l2cap_add_conf_opt(&ptr, L2CAP_CONF_MTU, 2, pi->omtu);
+ break;
+
+ case L2CAP_CONF_FLUSH_TO:
+ pi->flush_to = val;
+ l2cap_add_conf_opt(&ptr, L2CAP_CONF_FLUSH_TO, 2,
+ pi->flush_to);
+ break;
+
+ case L2CAP_CONF_QOS:
+ break;
+
+ case L2CAP_CONF_RFC:
+ /* Currently, the code does not support negotiating to
+ * use a different mode than was initially created. This
+ * can be used for switching between ERTM/Streaming, and
+ * will be useful for implementing MCAP/HDP on top of
+ * eL2CAP. */
+ *result = L2CAP_CONF_UNACCEPT;
+ if (pi->mode == L2CAP_MODE_BASIC)
+ pi->fcs = 0;
+ l2cap_add_conf_opt(&ptr, L2CAP_CONF_RFC,
+ sizeof(rfc), (unsigned long) &rfc);
+ break;
+
+ case L2CAP_CONF_FCS:
+ pi->fcs = val;
+ l2cap_add_conf_opt(&ptr, L2CAP_CONF_FCS, 1, pi->fcs);
+ }
+ }
+
+ req->dcid = cpu_to_le16(pi->dcid);
+ req->flags = cpu_to_le16(0x0000);
+
+ BT_DBG("ptr %p, req->data %p", ptr, req->data);
+ return ptr - _req;
+}
+
static int l2cap_build_conf_rsp(struct sock *sk, void *data, u16 result, u16 flags)
{
struct l2cap_conf_rsp *rsp = data;
@@ -2233,6 +2297,15 @@ static inline int l2cap_config_req(struct l2cap_conn *conn, struct l2cap_cmd_hdr
if (sk->sk_state == BT_DISCONN)
goto unlock;
+ /* Reject if connected and in eL2CAP mode. */
+ if (sk->sk_state == BT_CONNECTED && l2cap_pi(sk)->mode != L2CAP_MODE_BASIC)
+ {
+ l2cap_send_cmd(conn, cmd->ident, L2CAP_CONF_RSP,
+ l2cap_build_conf_rsp(sk, rsp,
+ L2CAP_CONF_REJECT, flags), rsp);
+ goto unlock;
+ }
+
/* Reject if config buffer is too small. */
len = cmd_len - sizeof(*req);
if (l2cap_pi(sk)->conf_len + len > sizeof(l2cap_pi(sk)->conf_req)) {
@@ -2301,21 +2374,36 @@ static inline int l2cap_config_rsp(struct l2cap_conn *conn, struct l2cap_cmd_hdr
if (!sk)
return 0;
+ /* Reject if connected and in eL2CAP mode. */
+ if (sk->sk_state == BT_CONNECTED && l2cap_pi(sk)->mode != L2CAP_MODE_BASIC)
+ {
+ l2cap_send_cmd(conn, cmd->ident, L2CAP_CONF_RSP,
+ l2cap_build_conf_rsp(sk, rsp,
+ L2CAP_CONF_REJECT, flags), rsp);
+ goto done;
+ }
+
switch (result) {
case L2CAP_CONF_SUCCESS:
break;
case L2CAP_CONF_UNACCEPT:
if (++l2cap_pi(sk)->conf_retry < L2CAP_CONF_MAX_RETRIES) {
- char req[128];
- /* It does not make sense to adjust L2CAP parameters
- * that are currently defined in the spec. We simply
- * resend config request that we sent earlier. It is
- * stupid, but it helps qualification testing which
- * expects at least some response from us. */
- l2cap_send_cmd(conn, l2cap_get_ident(conn), L2CAP_CONF_REQ,
- l2cap_build_conf_req(sk, req), req);
- goto done;
+ int len = cmd->len - sizeof(*rsp);
+ char req[64];
+
+ /* throw out any old conf requests we stored */
+ result = L2CAP_CONF_SUCCESS;
+ len = l2cap_parse_conf_rsp(sk, rsp->data, len, req,
+ &result);
+
+ BT_DBG("len %d", len);
+ l2cap_send_cmd(conn, l2cap_get_ident(conn),
+ L2CAP_CONF_REQ, len, req);
+ if (result == L2CAP_CONF_SUCCESS)
+ break;
+ else
+ goto done;
}
default:
--
1.6.0.6
--
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