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af_iucv: Modify iucv msg target class using control msghdr

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Allow 'classification' of socket data that is sent or received over
an af_iucv socket. For classification of data, the target class of an
(native) iucv message is used.

This patch provides the cmsg interface for iucv_sock_recvmsg() and
iucv_sock_sendmsg().  Applications can use the msg_control field of
struct msghdr to set or get the target class as a
"socket control message" (SCM/CMSG).

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Ursula Braun <ursula.braun@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Hendrik Brueckner 2009-04-21 23:26:24 +00:00 committed by David S. Miller
parent b8942e3b6c
commit 44b1e6b5f9
2 changed files with 78 additions and 4 deletions
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3
include/net/iucv/af_iucv.h
View File

@ -79,6 +79,9 @@ struct iucv_sock {
/* iucv socket options (SOL_IUCV) */
#define SO_IPRMDATA_MSG 0x0080 /* send/recv IPRM_DATA msgs */
/* iucv related control messages (scm) */
#define SCM_IUCV_TRGCLS 0x0001 /* target class control message */
struct iucv_sock_list {
struct hlist_head head;
rwlock_t lock;

79
net/iucv/af_iucv.c
View File

@ -45,6 +45,15 @@ static struct proto iucv_proto = {
static const u8 iprm_shutdown[8] =
{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01};
#define TRGCLS_SIZE (sizeof(((struct iucv_message *)0)->class))
/* macros to set/get socket control buffer at correct offset */
#define CB_TAG(skb) ((skb)->cb) /* iucv message tag */
#define CB_TAG_LEN (sizeof(((struct iucv_message *) 0)->tag))
#define CB_TRGCLS(skb) ((skb)->cb + CB_TAG_LEN) /* iucv msg target class */
#define CB_TRGCLS_LEN (TRGCLS_SIZE)
static void iucv_sock_kill(struct sock *sk);
static void iucv_sock_close(struct sock *sk);
@ -698,6 +707,8 @@ static int iucv_sock_sendmsg(struct kiocb *iocb, struct socket *sock,
struct iucv_sock *iucv = iucv_sk(sk);
struct sk_buff *skb;
struct iucv_message txmsg;
struct cmsghdr *cmsg;
int cmsg_done;
char user_id[9];
char appl_id[9];
int err;
@ -717,6 +728,48 @@ static int iucv_sock_sendmsg(struct kiocb *iocb, struct socket *sock,
}
if (sk->sk_state == IUCV_CONNECTED) {
/* initialize defaults */
cmsg_done = 0; /* check for duplicate headers */
txmsg.class = 0;
/* iterate over control messages */
for (cmsg = CMSG_FIRSTHDR(msg); cmsg;
cmsg = CMSG_NXTHDR(msg, cmsg)) {
if (!CMSG_OK(msg, cmsg)) {
err = -EINVAL;
goto out;
}
if (cmsg->cmsg_level != SOL_IUCV)
continue;
if (cmsg->cmsg_type & cmsg_done) {
err = -EINVAL;
goto out;
}
cmsg_done |= cmsg->cmsg_type;
switch (cmsg->cmsg_type) {
case SCM_IUCV_TRGCLS:
if (cmsg->cmsg_len != CMSG_LEN(TRGCLS_SIZE)) {
err = -EINVAL;
goto out;
}
/* set iucv message target class */
memcpy(&txmsg.class,
(void *) CMSG_DATA(cmsg), TRGCLS_SIZE);
break;
default:
err = -EINVAL;
goto out;
break;
}
}
if (!(skb = sock_alloc_send_skb(sk, len,
msg->msg_flags & MSG_DONTWAIT,
&err)))
@ -727,10 +780,9 @@ static int iucv_sock_sendmsg(struct kiocb *iocb, struct socket *sock,
goto fail;
}
txmsg.class = 0;
memcpy(&txmsg.class, skb->data, skb->len >= 4 ? 4 : skb->len);
/* increment and save iucv message tag for msg_completion cbk */
txmsg.tag = iucv->send_tag++;
memcpy(skb->cb, &txmsg.tag, 4);
memcpy(CB_TAG(skb), &txmsg.tag, CB_TAG_LEN);
skb_queue_tail(&iucv->send_skb_q, skb);
if (((iucv->path->flags & IUCV_IPRMDATA) & iucv->flags)
@ -801,6 +853,10 @@ static int iucv_fragment_skb(struct sock *sk, struct sk_buff *skb, int len)
if (!nskb)
return -ENOMEM;
/* copy target class to control buffer of new skb */
memcpy(CB_TRGCLS(nskb), CB_TRGCLS(skb), CB_TRGCLS_LEN);
/* copy data fragment */
memcpy(nskb->data, skb->data + copied, size);
copied += size;
dataleft -= size;
@ -824,6 +880,10 @@ static void iucv_process_message(struct sock *sk, struct sk_buff *skb,
len = iucv_msg_length(msg);
/* store msg target class in the second 4 bytes of skb ctrl buffer */
/* Note: the first 4 bytes are reserved for msg tag */
memcpy(CB_TRGCLS(skb), &msg->class, CB_TRGCLS_LEN);
/* check for special IPRM messages (e.g. iucv_sock_shutdown) */
if ((msg->flags & IUCV_IPRMDATA) && len > 7) {
if (memcmp(msg->rmmsg, iprm_shutdown, 8) == 0) {
@ -915,6 +975,17 @@ static int iucv_sock_recvmsg(struct kiocb *iocb, struct socket *sock,
len -= copied;
/* create control message to store iucv msg target class:
* get the trgcls from the control buffer of the skb due to
* fragmentation of original iucv message. */
err = put_cmsg(msg, SOL_IUCV, SCM_IUCV_TRGCLS,
CB_TRGCLS_LEN, CB_TRGCLS(skb));
if (err) {
if (!(flags & MSG_PEEK))
skb_queue_head(&sk->sk_receive_queue, skb);
return err;
}
/* Mark read part of skb as used */
if (!(flags & MSG_PEEK)) {
skb_pull(skb, copied);
@ -1316,7 +1387,7 @@ static void iucv_callback_txdone(struct iucv_path *path,
spin_lock_irqsave(&list->lock, flags);
while (list_skb != (struct sk_buff *)list) {
if (!memcmp(&msg->tag, list_skb->cb, 4)) {
if (!memcmp(&msg->tag, CB_TAG(list_skb), CB_TAG_LEN)) {
this = list_skb;
break;
}