From: Hendrik Brueckner <brueckner@xxxxxxxxxxxxxxxxxx>
This patch provides the socket type SOCK_SEQPACKET in addition to
SOCK_STREAM.
AF_IUCV sockets of type SOCK_SEQPACKET supports an 1:1 mapping of
socket read or write operations to complete IUCV messages.
Socket data or IUCV message data is not fragmented as this is the
case for SOCK_STREAM sockets.
The intention is to help application developers who write
applications or device drivers using native IUCV interfaces
(Linux kernel or z/VM IUCV interfaces).
Signed-off-by: Hendrik Brueckner <brueckner@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Ursula Braun <ursula.braun@xxxxxxxxxx>
---
net/iucv/af_iucv.c | 73 ++++++++++++++++++++++++++++++++++++++++-------------
1 file changed, 56 insertions(+), 17 deletions(-)
Index: net-2.6-uschi/net/iucv/af_iucv.c
===================================================================
--- net-2.6-uschi.orig/net/iucv/af_iucv.c
+++ net-2.6-uschi/net/iucv/af_iucv.c
@@ -292,11 +292,22 @@ static int iucv_sock_create(struct net *
{
struct sock *sk;
- if (sock->type != SOCK_STREAM)
- return -ESOCKTNOSUPPORT;
+ if (protocol && protocol != PF_IUCV)
+ return -EPROTONOSUPPORT;
sock->state = SS_UNCONNECTED;
- sock->ops = &iucv_sock_ops;
+
+ switch (sock->type) {
+ case SOCK_STREAM:
+ sock->ops = &iucv_sock_ops;
+ break;
+ case SOCK_SEQPACKET:
+ /* currently, proto ops can handle both sk types */
+ sock->ops = &iucv_sock_ops;
+ break;
+ default:
+ return -ESOCKTNOSUPPORT;
+ }
sk = iucv_sock_alloc(sock, protocol, GFP_KERNEL);
if (!sk)
@@ -507,11 +518,9 @@ static int iucv_sock_connect(struct sock
if (sk->sk_state != IUCV_OPEN && sk->sk_state != IUCV_BOUND)
return -EBADFD;
- if (sk->sk_type != SOCK_STREAM)
+ if (sk->sk_type != SOCK_STREAM && sk->sk_type != SOCK_SEQPACKET)
return -EINVAL;
- iucv = iucv_sk(sk);
-
if (sk->sk_state == IUCV_OPEN) {
err = iucv_sock_autobind(sk);
if (unlikely(err))
@@ -588,7 +597,10 @@ static int iucv_sock_listen(struct socke
lock_sock(sk);
err = -EINVAL;
- if (sk->sk_state != IUCV_BOUND || sock->type != SOCK_STREAM)
+ if (sk->sk_state != IUCV_BOUND)
+ goto done;
+
+ if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
goto done;
sk->sk_max_ack_backlog = backlog;
@@ -723,6 +735,10 @@ static int iucv_sock_sendmsg(struct kioc
if (msg->msg_flags & MSG_OOB)
return -EOPNOTSUPP;
+ /* SOCK_SEQPACKET: we do not support segmented records */
+ if (sk->sk_type == SOCK_SEQPACKET && !(msg->msg_flags & MSG_EOR))
+ return -EOPNOTSUPP;
+
lock_sock(sk);
if (sk->sk_shutdown & SEND_SHUTDOWN) {
@@ -773,6 +789,10 @@ static int iucv_sock_sendmsg(struct kioc
}
}
+ /* allocate one skb for each iucv message:
+ * this is fine for SOCK_SEQPACKET (unless we want to support
+ * segmented records using the MSG_EOR flag), but
+ * for SOCK_STREAM we might want to improve it in future */
if (!(skb = sock_alloc_send_skb(sk, len,
msg->msg_flags & MSG_DONTWAIT,
&err)))
@@ -900,7 +920,11 @@ static void iucv_process_message(struct
kfree_skb(skb);
return;
}
- if (skb->truesize >= sk->sk_rcvbuf / 4) {
+ /* we need to fragment iucv messages for SOCK_STREAM only;
+ * for SOCK_SEQPACKET, it is only relevant if we support
+ * record segmentation using MSG_EOR (see also recvmsg()) */
+ if (sk->sk_type == SOCK_STREAM &&
+ skb->truesize >= sk->sk_rcvbuf / 4) {
rc = iucv_fragment_skb(sk, skb, len);
kfree_skb(skb);
skb = NULL;
@@ -944,7 +968,8 @@ static int iucv_sock_recvmsg(struct kioc
int noblock = flags & MSG_DONTWAIT;
struct sock *sk = sock->sk;
struct iucv_sock *iucv = iucv_sk(sk);
- int target, copied = 0;
+ int target;
+ unsigned int copied, rlen;
struct sk_buff *skb, *rskb, *cskb;
int err = 0;
@@ -968,7 +993,8 @@ static int iucv_sock_recvmsg(struct kioc
return err;
}
- copied = min_t(unsigned int, skb->len, len);
+ rlen = skb->len; /* real length of skb */
+ copied = min_t(unsigned int, rlen, len);
cskb = skb;
if (memcpy_toiovec(msg->msg_iov, cskb->data, copied)) {
@@ -978,7 +1004,13 @@ static int iucv_sock_recvmsg(struct kioc
goto done;
}
- len -= copied;
+ /* SOCK_SEQPACKET: set MSG_TRUNC if recv buf size is too small */
+ if (sk->sk_type == SOCK_SEQPACKET) {
+ if (copied < rlen)
+ msg->msg_flags |= MSG_TRUNC;
+ /* each iucv message contains a complete record */
+ msg->msg_flags |= MSG_EOR;
+ }
/* create control message to store iucv msg target class:
* get the trgcls from the control buffer of the skb due to
@@ -993,11 +1025,14 @@ static int iucv_sock_recvmsg(struct kioc
/* Mark read part of skb as used */
if (!(flags & MSG_PEEK)) {
- skb_pull(skb, copied);
- if (skb->len) {
- skb_queue_head(&sk->sk_receive_queue, skb);
- goto done;
+ /* SOCK_STREAM: re-queue skb if it contains unreceived data */
+ if (sk->sk_type == SOCK_STREAM) {
+ skb_pull(skb, copied);
+ if (skb->len) {
+ skb_queue_head(&sk->sk_receive_queue, skb);
+ goto done;
+ }
}
kfree_skb(skb);
@@ -1022,7 +1057,11 @@ static int iucv_sock_recvmsg(struct kioc
}
done:
- return err ? : copied;
+ /* SOCK_SEQPACKET: return real length if MSG_TRUNC is set */
+ if (sk->sk_type == SOCK_SEQPACKET && (flags & MSG_TRUNC))
+ copied = rlen;
+
+ return copied;
}
static inline unsigned int iucv_accept_poll(struct sock *parent)
@@ -1287,7 +1326,7 @@ static int iucv_callback_connreq(struct
}
/* Create the new socket */
- nsk = iucv_sock_alloc(NULL, SOCK_STREAM, GFP_ATOMIC);
+ nsk = iucv_sock_alloc(NULL, sk->sk_type, GFP_ATOMIC);
if (!nsk) {
err = iucv_path_sever(path, user_data);
iucv_path_free(path);
--
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