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[LLC]: Fix the accept path

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Borrowing the structure of TCP/IP for this. On the receive of new connections I
was bh_lock_socking the _new_ sock, not the listening one, duh, now it survives
the ssh connections storm I've been using to test this specific bug.

Also fixes send side skb sock accounting.

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
This commit is contained in:
Arnaldo Carvalho de Melo 2005-09-22 07:57:21 -03:00
parent 2928c19e10
commit d389424e00
7 changed files with 133 additions and 94 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
include/net/llc_sap.h
View File

@ -19,7 +19,8 @@ struct sock;
extern void llc_sap_rtn_pdu(struct llc_sap *sap, struct sk_buff *skb);
extern void llc_save_primitive(struct sock *sk, struct sk_buff* skb,
unsigned char prim);
extern struct sk_buff *llc_alloc_frame(struct net_device *dev);
extern struct sk_buff *llc_alloc_frame(struct sock *sk,
struct net_device *dev);
extern void llc_build_and_send_test_pkt(struct llc_sap *sap,
struct sk_buff *skb,

64
net/llc/llc_c_ac.c
View File

@ -60,24 +60,10 @@ int llc_conn_ac_clear_remote_busy(struct sock *sk, struct sk_buff *skb)
int llc_conn_ac_conn_ind(struct sock *sk, struct sk_buff *skb)
{
int rc = -ENOTCONN;
u8 dsap;
struct llc_sap *sap;
struct llc_conn_state_ev *ev = llc_conn_ev(skb);
llc_pdu_decode_dsap(skb, &dsap);
sap = llc_sap_find(dsap);
if (sap) {
struct llc_conn_state_ev *ev = llc_conn_ev(skb);
struct llc_sock *llc = llc_sk(sk);
llc_pdu_decode_sa(skb, llc->daddr.mac);
llc_pdu_decode_da(skb, llc->laddr.mac);
llc->dev = skb->dev;
ev->ind_prim = LLC_CONN_PRIM;
rc = 0;
llc_sap_put(sap);
}
return rc;
ev->ind_prim = LLC_CONN_PRIM;
return 0;
}
int llc_conn_ac_conn_confirm(struct sock *sk, struct sk_buff *skb)
@ -213,7 +199,7 @@ int llc_conn_ac_send_disc_cmd_p_set_x(struct sock *sk, struct sk_buff *skb)
{
int rc = -ENOBUFS;
struct llc_sock *llc = llc_sk(sk);
struct sk_buff *nskb = llc_alloc_frame(llc->dev);
struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev);
if (nskb) {
struct llc_sap *sap = llc->sap;
@ -238,7 +224,7 @@ int llc_conn_ac_send_dm_rsp_f_set_p(struct sock *sk, struct sk_buff *skb)
{
int rc = -ENOBUFS;
struct llc_sock *llc = llc_sk(sk);
struct sk_buff *nskb = llc_alloc_frame(llc->dev);
struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev);
if (nskb) {
struct llc_sap *sap = llc->sap;
@ -264,7 +250,7 @@ int llc_conn_ac_send_dm_rsp_f_set_1(struct sock *sk, struct sk_buff *skb)
{
int rc = -ENOBUFS;
struct llc_sock *llc = llc_sk(sk);
struct sk_buff *nskb = llc_alloc_frame(llc->dev);
struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev);
if (nskb) {
struct llc_sap *sap = llc->sap;
@ -297,7 +283,7 @@ int llc_conn_ac_send_frmr_rsp_f_set_x(struct sock *sk, struct sk_buff *skb)
llc_pdu_decode_pf_bit(skb, &f_bit);
else
f_bit = 0;
nskb = llc_alloc_frame(llc->dev);
nskb = llc_alloc_frame(sk, llc->dev);
if (nskb) {
struct llc_sap *sap = llc->sap;
@ -321,7 +307,7 @@ int llc_conn_ac_resend_frmr_rsp_f_set_0(struct sock *sk, struct sk_buff *skb)
{
int rc = -ENOBUFS;
struct llc_sock *llc = llc_sk(sk);
struct sk_buff *nskb = llc_alloc_frame(llc->dev);
struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev);
if (nskb) {
struct llc_sap *sap = llc->sap;
@ -351,7 +337,7 @@ int llc_conn_ac_resend_frmr_rsp_f_set_p(struct sock *sk, struct sk_buff *skb)
struct llc_sock *llc = llc_sk(sk);
llc_pdu_decode_pf_bit(skb, &f_bit);
nskb = llc_alloc_frame(llc->dev);
nskb = llc_alloc_frame(sk, llc->dev);
if (nskb) {
struct llc_sap *sap = llc->sap;
struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
@ -439,7 +425,7 @@ int llc_conn_ac_resend_i_xxx_x_set_0_or_send_rr(struct sock *sk,
struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
int rc = -ENOBUFS;
struct llc_sock *llc = llc_sk(sk);
struct sk_buff *nskb = llc_alloc_frame(llc->dev);
struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev);
if (nskb) {
struct llc_sap *sap = llc->sap;
@ -474,7 +460,7 @@ int llc_conn_ac_send_rej_cmd_p_set_1(struct sock *sk, struct sk_buff *skb)
{
int rc = -ENOBUFS;
struct llc_sock *llc = llc_sk(sk);
struct sk_buff *nskb = llc_alloc_frame(llc->dev);
struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev);
if (nskb) {
struct llc_sap *sap = llc->sap;
@ -498,7 +484,7 @@ int llc_conn_ac_send_rej_rsp_f_set_1(struct sock *sk, struct sk_buff *skb)
{
int rc = -ENOBUFS;
struct llc_sock *llc = llc_sk(sk);
struct sk_buff *nskb = llc_alloc_frame(llc->dev);
struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev);
if (nskb) {
struct llc_sap *sap = llc->sap;
@ -522,7 +508,7 @@ int llc_conn_ac_send_rej_xxx_x_set_0(struct sock *sk, struct sk_buff *skb)
{
int rc = -ENOBUFS;
struct llc_sock *llc = llc_sk(sk);
struct sk_buff *nskb = llc_alloc_frame(llc->dev);
struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev);
if (nskb) {
struct llc_sap *sap = llc->sap;
@ -546,7 +532,7 @@ int llc_conn_ac_send_rnr_cmd_p_set_1(struct sock *sk, struct sk_buff *skb)
{
int rc = -ENOBUFS;
struct llc_sock *llc = llc_sk(sk);
struct sk_buff *nskb = llc_alloc_frame(llc->dev);
struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev);
if (nskb) {
struct llc_sap *sap = llc->sap;
@ -570,7 +556,7 @@ int llc_conn_ac_send_rnr_rsp_f_set_1(struct sock *sk, struct sk_buff *skb)
{
int rc = -ENOBUFS;
struct llc_sock *llc = llc_sk(sk);
struct sk_buff *nskb = llc_alloc_frame(llc->dev);
struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev);
if (nskb) {
struct llc_sap *sap = llc->sap;
@ -594,7 +580,7 @@ int llc_conn_ac_send_rnr_xxx_x_set_0(struct sock *sk, struct sk_buff *skb)
{
int rc = -ENOBUFS;
struct llc_sock *llc = llc_sk(sk);
struct sk_buff *nskb = llc_alloc_frame(llc->dev);
struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev);
if (nskb) {
struct llc_sap *sap = llc->sap;
@ -630,7 +616,7 @@ int llc_conn_ac_opt_send_rnr_xxx_x_set_0(struct sock *sk, struct sk_buff *skb)
{
int rc = -ENOBUFS;
struct llc_sock *llc = llc_sk(sk);
struct sk_buff *nskb = llc_alloc_frame(llc->dev);
struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev);
if (nskb) {
struct llc_sap *sap = llc->sap;
@ -654,7 +640,7 @@ int llc_conn_ac_send_rr_cmd_p_set_1(struct sock *sk, struct sk_buff *skb)
{
int rc = -ENOBUFS;
struct llc_sock *llc = llc_sk(sk);
struct sk_buff *nskb = llc_alloc_frame(llc->dev);
struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev);
if (nskb) {
struct llc_sap *sap = llc->sap;
@ -678,7 +664,7 @@ int llc_conn_ac_send_rr_rsp_f_set_1(struct sock *sk, struct sk_buff *skb)
{
int rc = -ENOBUFS;
struct llc_sock *llc = llc_sk(sk);
struct sk_buff *nskb = llc_alloc_frame(llc->dev);
struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev);
if (nskb) {
struct llc_sap *sap = llc->sap;
@ -703,7 +689,7 @@ int llc_conn_ac_send_ack_rsp_f_set_1(struct sock *sk, struct sk_buff *skb)
{
int rc = -ENOBUFS;
struct llc_sock *llc = llc_sk(sk);
struct sk_buff *nskb = llc_alloc_frame(llc->dev);
struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev);
if (nskb) {
struct llc_sap *sap = llc->sap;
@ -727,7 +713,7 @@ int llc_conn_ac_send_rr_xxx_x_set_0(struct sock *sk, struct sk_buff *skb)
{
int rc = -ENOBUFS;
struct llc_sock *llc = llc_sk(sk);
struct sk_buff *nskb = llc_alloc_frame(llc->dev);
struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev);
if (nskb) {
struct llc_sap *sap = llc->sap;
@ -751,7 +737,7 @@ int llc_conn_ac_send_ack_xxx_x_set_0(struct sock *sk, struct sk_buff *skb)
{
int rc = -ENOBUFS;
struct llc_sock *llc = llc_sk(sk);
struct sk_buff *nskb = llc_alloc_frame(llc->dev);
struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev);
if (nskb) {
struct llc_sap *sap = llc->sap;
@ -785,7 +771,7 @@ int llc_conn_ac_send_sabme_cmd_p_set_x(struct sock *sk, struct sk_buff *skb)
{
int rc = -ENOBUFS;
struct llc_sock *llc = llc_sk(sk);
struct sk_buff *nskb = llc_alloc_frame(llc->dev);
struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev);
if (nskb) {
struct llc_sap *sap = llc->sap;
@ -814,7 +800,7 @@ int llc_conn_ac_send_ua_rsp_f_set_p(struct sock *sk, struct sk_buff *skb)
u8 f_bit;
int rc = -ENOBUFS;
struct llc_sock *llc = llc_sk(sk);
struct sk_buff *nskb = llc_alloc_frame(llc->dev);
struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev);
llc_pdu_decode_pf_bit(skb, &f_bit);
if (nskb) {
@ -970,7 +956,7 @@ static int llc_conn_ac_send_rr_rsp_f_set_ackpf(struct sock *sk,
{
int rc = -ENOBUFS;
struct llc_sock *llc = llc_sk(sk);
struct sk_buff *nskb = llc_alloc_frame(llc->dev);
struct sk_buff *nskb = llc_alloc_frame(sk, llc->dev);
if (nskb) {
struct llc_sap *sap = llc->sap;

144
net/llc/llc_conn.c
View File

@ -58,7 +58,7 @@ int sysctl_llc2_busy_timeout = LLC2_BUSY_TIME * HZ;
int llc_conn_state_process(struct sock *sk, struct sk_buff *skb)
{
int rc;
struct llc_sock *llc = llc_sk(sk);
struct llc_sock *llc = llc_sk(skb->sk);
struct llc_conn_state_ev *ev = llc_conn_ev(skb);
/*
@ -68,7 +68,10 @@ int llc_conn_state_process(struct sock *sk, struct sk_buff *skb)
*/
skb_get(skb);
ev->ind_prim = ev->cfm_prim = 0;
rc = llc_conn_service(sk, skb); /* sending event to state machine */
/*
* Send event to state machine
*/
rc = llc_conn_service(skb->sk, skb);
if (unlikely(rc != 0)) {
printk(KERN_ERR "%s: llc_conn_service failed\n", __FUNCTION__);
goto out_kfree_skb;
@ -100,18 +103,14 @@ int llc_conn_state_process(struct sock *sk, struct sk_buff *skb)
kfree_skb(skb);
}
break;
case LLC_CONN_PRIM: {
struct sock *parent = skb->sk;
skb_orphan(skb);
case LLC_CONN_PRIM:
/*
* Set the skb->sk to the new struct sock, so that at accept
* type the upper layer can get the newly created struct sock.
* Can't be sock_queue_rcv_skb, because we have to leave the
* skb->sk pointing to the newly created struct sock in
* llc_conn_handler. -acme
*/
skb->sk = sk;
skb_queue_tail(&parent->sk_receive_queue, skb);
sk->sk_state_change(parent);
}
skb_queue_tail(&sk->sk_receive_queue, skb);
sk->sk_state_change(sk);
break;
case LLC_DISC_PRIM:
sock_hold(sk);
@ -475,7 +474,7 @@ static int llc_exec_conn_trans_actions(struct sock *sk,
}
/**
* llc_lookup_established - Finds connection for the remote/local sap/mac
* __llc_lookup_established - Finds connection for the remote/local sap/mac
* @sap: SAP
* @daddr: address of remote LLC (MAC + SAP)
* @laddr: address of local LLC (MAC + SAP)
@ -483,14 +482,16 @@ static int llc_exec_conn_trans_actions(struct sock *sk,
* Search connection list of the SAP and finds connection using the remote
* mac, remote sap, local mac, and local sap. Returns pointer for
* connection found, %NULL otherwise.
* Caller has to make sure local_bh is disabled.
*/
struct sock *llc_lookup_established(struct llc_sap *sap, struct llc_addr *daddr,
struct llc_addr *laddr)
static struct sock *__llc_lookup_established(struct llc_sap *sap,
struct llc_addr *daddr,
struct llc_addr *laddr)
{
struct sock *rc;
struct hlist_node *node;
read_lock_bh(&sap->sk_list.lock);
read_lock(&sap->sk_list.lock);
sk_for_each(rc, node, &sap->sk_list.list) {
struct llc_sock *llc = llc_sk(rc);
@ -504,10 +505,22 @@ struct sock *llc_lookup_established(struct llc_sap *sap, struct llc_addr *daddr,
}
rc = NULL;
found:
read_unlock_bh(&sap->sk_list.lock);
read_unlock(&sap->sk_list.lock);
return rc;
}
struct sock *llc_lookup_established(struct llc_sap *sap,
struct llc_addr *daddr,
struct llc_addr *laddr)
{
struct sock *sk;
local_bh_disable();
sk = __llc_lookup_established(sap, daddr, laddr);
local_bh_enable();
return sk;
}
/**
* llc_lookup_listener - Finds listener for local MAC + SAP
* @sap: SAP
@ -516,6 +529,7 @@ found:
* Search connection list of the SAP and finds connection listening on
* local mac, and local sap. Returns pointer for parent socket found,
* %NULL otherwise.
* Caller has to make sure local_bh is disabled.
*/
static struct sock *llc_lookup_listener(struct llc_sap *sap,
struct llc_addr *laddr)
@ -523,7 +537,7 @@ static struct sock *llc_lookup_listener(struct llc_sap *sap,
struct sock *rc;
struct hlist_node *node;
read_lock_bh(&sap->sk_list.lock);
read_lock(&sap->sk_list.lock);
sk_for_each(rc, node, &sap->sk_list.list) {
struct llc_sock *llc = llc_sk(rc);
@ -537,10 +551,19 @@ static struct sock *llc_lookup_listener(struct llc_sap *sap,
}
rc = NULL;
found:
read_unlock_bh(&sap->sk_list.lock);
read_unlock(&sap->sk_list.lock);
return rc;
}
static struct sock *__llc_lookup(struct llc_sap *sap,
struct llc_addr *daddr,
struct llc_addr *laddr)
{
struct sock *sk = __llc_lookup_established(sap, daddr, laddr);
return sk ? : llc_lookup_listener(sap, laddr);
}
/**
* llc_data_accept_state - designates if in this state data can be sent.
* @state: state of connection.
@ -666,15 +689,34 @@ void llc_sap_remove_socket(struct llc_sap *sap, struct sock *sk)
static int llc_conn_rcv(struct sock* sk, struct sk_buff *skb)
{
struct llc_conn_state_ev *ev = llc_conn_ev(skb);
struct llc_sock *llc = llc_sk(sk);
if (!llc->dev)
llc->dev = skb->dev;
ev->type = LLC_CONN_EV_TYPE_PDU;
ev->reason = 0;
return llc_conn_state_process(sk, skb);
}
static struct sock *llc_create_incoming_sock(struct sock *sk,
struct net_device *dev,
struct llc_addr *saddr,
struct llc_addr *daddr)
{
struct sock *newsk = llc_sk_alloc(sk->sk_family, GFP_ATOMIC,
sk->sk_prot);
struct llc_sock *newllc, *llc = llc_sk(sk);
if (!newsk)
goto out;
newllc = llc_sk(newsk);
memcpy(&newllc->laddr, daddr, sizeof(newllc->laddr));
memcpy(&newllc->daddr, saddr, sizeof(newllc->daddr));
newllc->dev = dev;
dev_hold(dev);
llc_sap_add_socket(llc->sap, newsk);
llc_sap_hold(llc->sap);
out:
return newsk;
}
void llc_conn_handler(struct llc_sap *sap, struct sk_buff *skb)
{
struct llc_addr saddr, daddr;
@ -685,34 +727,35 @@ void llc_conn_handler(struct llc_sap *sap, struct sk_buff *skb)
llc_pdu_decode_da(skb, daddr.mac);
llc_pdu_decode_dsap(skb, &daddr.lsap);
sk = llc_lookup_established(sap, &saddr, &daddr);
if (!sk) {
/*
* Didn't find an active connection; verify if there
* is a listening socket for this llc addr
*/
struct llc_sock *llc;
struct sock *parent = llc_lookup_listener(sap, &daddr);
sk = __llc_lookup(sap, &saddr, &daddr);
if (!sk)
goto drop;
if (!parent) {
dprintk("llc_lookup_listener failed!\n");
goto drop;
}
sk = llc_sk_alloc(parent->sk_family, GFP_ATOMIC, parent->sk_prot);
if (!sk) {
sock_put(parent);
goto drop;
}
llc = llc_sk(sk);
memcpy(&llc->laddr, &daddr, sizeof(llc->laddr));
memcpy(&llc->daddr, &saddr, sizeof(llc->daddr));
llc_sap_add_socket(sap, sk);
sock_hold(sk);
skb_set_owner_r(skb, parent);
sock_put(parent);
}
bh_lock_sock(sk);
/*
* This has to be done here and not at the upper layer ->accept
* method because of the way the PROCOM state machine works:
* it needs to set several state variables (see, for instance,
* llc_adm_actions_2 in net/llc/llc_c_st.c) and send a packet to
* the originator of the new connection, and this state has to be
* in the newly created struct sock private area. -acme
*/
if (unlikely(sk->sk_state == TCP_LISTEN)) {
struct sock *newsk = llc_create_incoming_sock(sk, skb->dev,
&saddr, &daddr);
if (!newsk)
goto drop_unlock;
skb_set_owner_r(skb, newsk);
} else {
/*
* Can't be skb_set_owner_r, this will be done at the
* llc_conn_state_process function, later on, when we will use
* skb_queue_rcv_skb to send it to upper layers, this is
* another trick required to cope with how the PROCOM state
* machine works. -acme
*/
skb->sk = sk;
}
if (!sock_owned_by_user(sk))
llc_conn_rcv(sk, skb);
else {
@ -720,11 +763,16 @@ void llc_conn_handler(struct llc_sap *sap, struct sk_buff *skb)
llc_set_backlog_type(skb, LLC_PACKET);
sk_add_backlog(sk, skb);
}
out:
bh_unlock_sock(sk);
sock_put(sk);
return;
drop:
kfree_skb(skb);
return;
drop_unlock:
kfree_skb(skb);
goto out;
}
#undef LLC_REFCNT_DEBUG

2
net/llc/llc_if.c
View File

@ -107,6 +107,7 @@ int llc_establish_connection(struct sock *sk, u8 *lmac, u8 *dmac, u8 dsap)
ev->type = LLC_CONN_EV_TYPE_PRIM;
ev->prim = LLC_CONN_PRIM;
ev->prim_type = LLC_PRIM_TYPE_REQ;
skb_set_owner_w(skb, sk);
rc = llc_conn_state_process(sk, skb);
}
out_put:
@ -141,6 +142,7 @@ int llc_send_disc(struct sock *sk)
skb = alloc_skb(0, GFP_ATOMIC);
if (!skb)
goto out;
skb_set_owner_w(skb, sk);
sk->sk_state = TCP_CLOSING;
ev = llc_conn_ev(skb);
ev->type = LLC_CONN_EV_TYPE_PRIM;

4
net/llc/llc_s_ac.c
View File

@ -103,7 +103,7 @@ int llc_sap_action_send_xid_r(struct llc_sap *sap, struct sk_buff *skb)
llc_pdu_decode_sa(skb, mac_da);
llc_pdu_decode_da(skb, mac_sa);
llc_pdu_decode_ssap(skb, &dsap);
nskb = llc_alloc_frame(skb->dev);
nskb = llc_alloc_frame(NULL, skb->dev);
if (!nskb)
goto out;
llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, sap->laddr.lsap, dsap,
@ -148,7 +148,7 @@ int llc_sap_action_send_test_r(struct llc_sap *sap, struct sk_buff *skb)
llc_pdu_decode_sa(skb, mac_da);
llc_pdu_decode_da(skb, mac_sa);
llc_pdu_decode_ssap(skb, &dsap);
nskb = llc_alloc_frame(skb->dev);
nskb = llc_alloc_frame(NULL, skb->dev);
if (!nskb)
goto out;
llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, sap->laddr.lsap, dsap,

4
net/llc/llc_sap.c
View File

@ -31,7 +31,7 @@
* Allocates an sk_buff for frame and initializes sk_buff fields.
* Returns allocated skb or %NULL when out of memory.
*/
struct sk_buff *llc_alloc_frame(struct net_device *dev)
struct sk_buff *llc_alloc_frame(struct sock *sk, struct net_device *dev)
{
struct sk_buff *skb = alloc_skb(128, GFP_ATOMIC);
@ -41,6 +41,8 @@ struct sk_buff *llc_alloc_frame(struct net_device *dev)
skb->protocol = htons(ETH_P_802_2);
skb->dev = dev;
skb->mac.raw = skb->head;
if (sk != NULL)
skb_set_owner_w(skb, sk);
}
return skb;
}

6
net/llc/llc_station.c
View File

@ -254,7 +254,7 @@ static int llc_station_ac_inc_xid_r_cnt_by_1(struct sk_buff *skb)
static int llc_station_ac_send_null_dsap_xid_c(struct sk_buff *skb)
{
int rc = 1;
struct sk_buff *nskb = llc_alloc_frame(skb->dev);
struct sk_buff *nskb = llc_alloc_frame(NULL, skb->dev);
if (!nskb)
goto out;
@ -275,7 +275,7 @@ static int llc_station_ac_send_xid_r(struct sk_buff *skb)
{
u8 mac_da[ETH_ALEN], dsap;
int rc = 1;
struct sk_buff* nskb = llc_alloc_frame(skb->dev);
struct sk_buff* nskb = llc_alloc_frame(NULL, skb->dev);
if (!nskb)
goto out;
@ -299,7 +299,7 @@ static int llc_station_ac_send_test_r(struct sk_buff *skb)
{
u8 mac_da[ETH_ALEN], dsap;
int rc = 1;
struct sk_buff *nskb = llc_alloc_frame(skb->dev);
struct sk_buff *nskb = llc_alloc_frame(NULL, skb->dev);
if (!nskb)
goto out;