[AF_IUCV]: Implementation of a skb backlog queue
With the inital implementation we missed to implement a skb backlog
queue . The result is that socket receive processing tossed packets.
Since AF_IUCV connections are working synchronously it leads to
connection hangs. Problems with read, close and select also occured.
Using a skb backlog queue is fixing all of these problems .
Signed-off-by: Jennifer Hunt <jenhunt@us.ibm.com>
Signed-off-by: Frank Pavlic <fpavlic@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/iucv/af_iucv.h b/include/net/iucv/af_iucv.h
index 04d1abb..f9bd11b 100644
--- a/include/net/iucv/af_iucv.h
+++ b/include/net/iucv/af_iucv.h
@@ -28,6 +28,7 @@
IUCV_LISTEN,
IUCV_SEVERED,
IUCV_DISCONN,
+ IUCV_CLOSING,
IUCV_CLOSED
};
@@ -62,6 +63,7 @@
struct sock *parent;
struct iucv_path *path;
struct sk_buff_head send_skb_q;
+ struct sk_buff_head backlog_skb_q;
unsigned int send_tag;
};
diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c
index e84c924..026704a 100644
--- a/net/iucv/af_iucv.c
+++ b/net/iucv/af_iucv.c
@@ -147,6 +147,7 @@
unsigned char user_data[16];
struct iucv_sock *iucv = iucv_sk(sk);
int err;
+ unsigned long timeo;
iucv_sock_clear_timer(sk);
lock_sock(sk);
@@ -159,6 +160,21 @@
case IUCV_CONNECTED:
case IUCV_DISCONN:
err = 0;
+
+ sk->sk_state = IUCV_CLOSING;
+ sk->sk_state_change(sk);
+
+ if(!skb_queue_empty(&iucv->send_skb_q)) {
+ if (sock_flag(sk, SOCK_LINGER) && sk->sk_lingertime)
+ timeo = sk->sk_lingertime;
+ else
+ timeo = IUCV_DISCONN_TIMEOUT;
+ err = iucv_sock_wait_state(sk, IUCV_CLOSED, 0, timeo);
+ }
+
+ sk->sk_state = IUCV_CLOSED;
+ sk->sk_state_change(sk);
+
if (iucv->path) {
low_nmcpy(user_data, iucv->src_name);
high_nmcpy(user_data, iucv->dst_name);
@@ -168,12 +184,11 @@
iucv->path = NULL;
}
- sk->sk_state = IUCV_CLOSED;
- sk->sk_state_change(sk);
sk->sk_err = ECONNRESET;
sk->sk_state_change(sk);
skb_queue_purge(&iucv->send_skb_q);
+ skb_queue_purge(&iucv->backlog_skb_q);
sock_set_flag(sk, SOCK_ZAPPED);
break;
@@ -204,6 +219,7 @@
sock_init_data(sock, sk);
INIT_LIST_HEAD(&iucv_sk(sk)->accept_q);
skb_queue_head_init(&iucv_sk(sk)->send_skb_q);
+ skb_queue_head_init(&iucv_sk(sk)->backlog_skb_q);
iucv_sk(sk)->send_tag = 0;
sk->sk_destruct = iucv_sock_destruct;
@@ -510,7 +526,7 @@
long timeo;
int err = 0;
- lock_sock(sk);
+ lock_sock_nested(sk, SINGLE_DEPTH_NESTING);
if (sk->sk_state != IUCV_LISTEN) {
err = -EBADFD;
@@ -530,7 +546,7 @@
release_sock(sk);
timeo = schedule_timeout(timeo);
- lock_sock(sk);
+ lock_sock_nested(sk, SINGLE_DEPTH_NESTING);
if (sk->sk_state != IUCV_LISTEN) {
err = -EBADFD;
@@ -606,7 +622,7 @@
if(!(skb = sock_alloc_send_skb(sk, len,
msg->msg_flags & MSG_DONTWAIT,
&err)))
- return err;
+ goto out;
if (memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len)){
err = -EFAULT;
@@ -647,10 +663,16 @@
{
int noblock = flags & MSG_DONTWAIT;
struct sock *sk = sock->sk;
+ struct iucv_sock *iucv = iucv_sk(sk);
int target, copied = 0;
- struct sk_buff *skb;
+ struct sk_buff *skb, *rskb, *cskb;
int err = 0;
+ if ((sk->sk_state == IUCV_DISCONN || sk->sk_state == IUCV_SEVERED) &&
+ skb_queue_empty(&iucv->backlog_skb_q) &&
+ skb_queue_empty(&sk->sk_receive_queue))
+ return 0;
+
if (flags & (MSG_OOB))
return -EOPNOTSUPP;
@@ -665,10 +687,12 @@
copied = min_t(unsigned int, skb->len, len);
- if (memcpy_toiovec(msg->msg_iov, skb->data, copied)) {
+ cskb = skb;
+ if (memcpy_toiovec(msg->msg_iov, cskb->data, copied)) {
skb_queue_head(&sk->sk_receive_queue, skb);
if (copied == 0)
return -EFAULT;
+ goto done;
}
len -= copied;
@@ -683,6 +707,18 @@
}
kfree_skb(skb);
+
+ /* Queue backlog skbs */
+ rskb = skb_dequeue(&iucv_sk(sk)->backlog_skb_q);
+ while(rskb) {
+ if (sock_queue_rcv_skb(sk, rskb)) {
+ skb_queue_head(&iucv_sk(sk)->backlog_skb_q,
+ rskb);
+ break;
+ } else {
+ rskb = skb_dequeue(&iucv_sk(sk)->backlog_skb_q);
+ }
+ }
} else
skb_queue_head(&sk->sk_receive_queue, skb);
@@ -732,6 +768,9 @@
if (sk->sk_state == IUCV_CLOSED)
mask |= POLLHUP;
+ if (sk->sk_state == IUCV_DISCONN || sk->sk_state == IUCV_SEVERED)
+ mask |= POLLIN;
+
if (sock_writeable(sk))
mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
else
@@ -817,13 +856,6 @@
iucv_sk(sk)->path = NULL;
}
- if (sock_flag(sk, SOCK_LINGER) && sk->sk_lingertime){
- lock_sock(sk);
- err = iucv_sock_wait_state(sk, IUCV_CLOSED, 0,
- sk->sk_lingertime);
- release_sock(sk);
- }
-
sock_orphan(sk);
iucv_sock_kill(sk);
return err;
@@ -927,18 +959,52 @@
sk->sk_state_change(sk);
}
+static int iucv_fragment_skb(struct sock *sk, struct sk_buff *skb, int len,
+ struct sk_buff_head fragmented_skb_q)
+{
+ int dataleft, size, copied = 0;
+ struct sk_buff *nskb;
+
+ dataleft = len;
+ while(dataleft) {
+ if (dataleft >= sk->sk_rcvbuf / 4)
+ size = sk->sk_rcvbuf / 4;
+ else
+ size = dataleft;
+
+ nskb = alloc_skb(size, GFP_ATOMIC | GFP_DMA);
+ if (!nskb)
+ return -ENOMEM;
+
+ memcpy(nskb->data, skb->data + copied, size);
+ copied += size;
+ dataleft -= size;
+
+ nskb->h.raw = nskb->data;
+ nskb->nh.raw = nskb->data;
+ nskb->len = size;
+
+ skb_queue_tail(fragmented_skb_q, nskb);
+ }
+
+ return 0;
+}
static void iucv_callback_rx(struct iucv_path *path, struct iucv_message *msg)
{
struct sock *sk = path->private;
- struct sk_buff *skb;
+ struct iucv_sock *iucv = iucv_sk(sk);
+ struct sk_buff *skb, *fskb;
+ struct sk_buff_head fragmented_skb_q;
int rc;
+ skb_queue_head_init(&fragmented_skb_q);
+
if (sk->sk_shutdown & RCV_SHUTDOWN)
return;
skb = alloc_skb(msg->length, GFP_ATOMIC | GFP_DMA);
if (!skb) {
- iucv_message_reject(path, msg);
+ iucv_path_sever(path, NULL);
return;
}
@@ -952,14 +1018,39 @@
kfree_skb(skb);
return;
}
-
- skb_reset_transport_header(skb);
- skb_reset_network_header(skb);
- skb->len = msg->length;
+ if (skb->truesize >= sk->sk_rcvbuf / 4) {
+ rc = iucv_fragment_skb(sk, skb, msg->length,
+ &fragmented_skb_q);
+ kfree_skb(skb);
+ skb = NULL;
+ if (rc) {
+ iucv_path_sever(path, NULL);
+ return;
+ }
+ } else {
+ skb_reset_transport_header(skb);
+ skb_reset_network_header(skb);
+ skb->len = msg->length;
+ }
+ }
+ /* Queue the fragmented skb */
+ fskb = skb_dequeue(&fragmented_skb_q);
+ while(fskb) {
+ if (!skb_queue_empty(&iucv->backlog_skb_q))
+ skb_queue_tail(&iucv->backlog_skb_q, fskb);
+ else if (sock_queue_rcv_skb(sk, fskb))
+ skb_queue_tail(&iucv_sk(sk)->backlog_skb_q, fskb);
+ fskb = skb_dequeue(&fragmented_skb_q);
}
- if (sock_queue_rcv_skb(sk, skb))
- kfree_skb(skb);
+ /* Queue the original skb if it exists (was not fragmented) */
+ if (skb) {
+ if (!skb_queue_empty(&iucv->backlog_skb_q))
+ skb_queue_tail(&iucv_sk(sk)->backlog_skb_q, skb);
+ else if (sock_queue_rcv_skb(sk, skb))
+ skb_queue_tail(&iucv_sk(sk)->backlog_skb_q, skb);
+ }
+
}
static void iucv_callback_txdone(struct iucv_path *path,
@@ -971,17 +1062,27 @@
struct sk_buff *list_skb = list->next;
unsigned long flags;
- spin_lock_irqsave(&list->lock, flags);
+ if (list_skb) {
+ spin_lock_irqsave(&list->lock, flags);
- do {
- this = list_skb;
- list_skb = list_skb->next;
- } while (memcmp(&msg->tag, this->cb, 4));
+ do {
+ this = list_skb;
+ list_skb = list_skb->next;
+ } while (memcmp(&msg->tag, this->cb, 4) && list_skb);
- spin_unlock_irqrestore(&list->lock, flags);
+ spin_unlock_irqrestore(&list->lock, flags);
- skb_unlink(this, &iucv_sk(sk)->send_skb_q);
- kfree_skb(this);
+ skb_unlink(this, &iucv_sk(sk)->send_skb_q);
+ kfree_skb(this);
+ }
+
+ if (sk->sk_state == IUCV_CLOSING){
+ if (skb_queue_empty(&iucv_sk(sk)->send_skb_q)) {
+ sk->sk_state = IUCV_CLOSED;
+ sk->sk_state_change(sk);
+ }
+ }
+
}
static void iucv_callback_connrej(struct iucv_path *path, u8 ipuser[16])