af_iucv: Modify iucv msg target class using control msghdr
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
David S. Miller
parent
b8942e3b6c
commit
44b1e6b5f9
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@ -79,6 +79,9 @@ struct iucv_sock {
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/* iucv socket options (SOL_IUCV) */
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#define SO_IPRMDATA_MSG 0x0080 /* send/recv IPRM_DATA msgs */
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/* iucv related control messages (scm) */
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#define SCM_IUCV_TRGCLS 0x0001 /* target class control message */
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struct iucv_sock_list {
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struct hlist_head head;
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rwlock_t lock;
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@ -45,6 +45,15 @@ static struct proto iucv_proto = {
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static const u8 iprm_shutdown[8] =
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{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01};
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#define TRGCLS_SIZE (sizeof(((struct iucv_message *)0)->class))
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/* macros to set/get socket control buffer at correct offset */
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#define CB_TAG(skb) ((skb)->cb) /* iucv message tag */
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#define CB_TAG_LEN (sizeof(((struct iucv_message *) 0)->tag))
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#define CB_TRGCLS(skb) ((skb)->cb + CB_TAG_LEN) /* iucv msg target class */
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#define CB_TRGCLS_LEN (TRGCLS_SIZE)
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static void iucv_sock_kill(struct sock *sk);
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static void iucv_sock_close(struct sock *sk);
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@ -698,6 +707,8 @@ static int iucv_sock_sendmsg(struct kiocb *iocb, struct socket *sock,
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struct iucv_sock *iucv = iucv_sk(sk);
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struct sk_buff *skb;
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struct iucv_message txmsg;
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struct cmsghdr *cmsg;
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int cmsg_done;
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char user_id[9];
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char appl_id[9];
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int err;
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@ -717,6 +728,48 @@ static int iucv_sock_sendmsg(struct kiocb *iocb, struct socket *sock,
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}
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if (sk->sk_state == IUCV_CONNECTED) {
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/* initialize defaults */
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cmsg_done = 0; /* check for duplicate headers */
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txmsg.class = 0;
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/* iterate over control messages */
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for (cmsg = CMSG_FIRSTHDR(msg); cmsg;
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cmsg = CMSG_NXTHDR(msg, cmsg)) {
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if (!CMSG_OK(msg, cmsg)) {
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err = -EINVAL;
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goto out;
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}
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if (cmsg->cmsg_level != SOL_IUCV)
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continue;
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if (cmsg->cmsg_type & cmsg_done) {
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err = -EINVAL;
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goto out;
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}
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cmsg_done |= cmsg->cmsg_type;
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switch (cmsg->cmsg_type) {
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case SCM_IUCV_TRGCLS:
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if (cmsg->cmsg_len != CMSG_LEN(TRGCLS_SIZE)) {
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err = -EINVAL;
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goto out;
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}
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/* set iucv message target class */
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memcpy(&txmsg.class,
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(void *) CMSG_DATA(cmsg), TRGCLS_SIZE);
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break;
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default:
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err = -EINVAL;
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goto out;
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break;
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}
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}
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if (!(skb = sock_alloc_send_skb(sk, len,
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msg->msg_flags & MSG_DONTWAIT,
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&err)))
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@ -727,10 +780,9 @@ static int iucv_sock_sendmsg(struct kiocb *iocb, struct socket *sock,
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goto fail;
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}
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txmsg.class = 0;
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memcpy(&txmsg.class, skb->data, skb->len >= 4 ? 4 : skb->len);
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/* increment and save iucv message tag for msg_completion cbk */
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txmsg.tag = iucv->send_tag++;
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memcpy(skb->cb, &txmsg.tag, 4);
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memcpy(CB_TAG(skb), &txmsg.tag, CB_TAG_LEN);
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skb_queue_tail(&iucv->send_skb_q, skb);
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if (((iucv->path->flags & IUCV_IPRMDATA) & iucv->flags)
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@ -801,6 +853,10 @@ static int iucv_fragment_skb(struct sock *sk, struct sk_buff *skb, int len)
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if (!nskb)
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return -ENOMEM;
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/* copy target class to control buffer of new skb */
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memcpy(CB_TRGCLS(nskb), CB_TRGCLS(skb), CB_TRGCLS_LEN);
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/* copy data fragment */
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memcpy(nskb->data, skb->data + copied, size);
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copied += size;
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dataleft -= size;
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@ -824,6 +880,10 @@ static void iucv_process_message(struct sock *sk, struct sk_buff *skb,
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len = iucv_msg_length(msg);
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/* store msg target class in the second 4 bytes of skb ctrl buffer */
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/* Note: the first 4 bytes are reserved for msg tag */
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memcpy(CB_TRGCLS(skb), &msg->class, CB_TRGCLS_LEN);
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/* check for special IPRM messages (e.g. iucv_sock_shutdown) */
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if ((msg->flags & IUCV_IPRMDATA) && len > 7) {
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if (memcmp(msg->rmmsg, iprm_shutdown, 8) == 0) {
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@ -915,6 +975,17 @@ static int iucv_sock_recvmsg(struct kiocb *iocb, struct socket *sock,
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len -= copied;
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/* create control message to store iucv msg target class:
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* get the trgcls from the control buffer of the skb due to
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* fragmentation of original iucv message. */
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err = put_cmsg(msg, SOL_IUCV, SCM_IUCV_TRGCLS,
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CB_TRGCLS_LEN, CB_TRGCLS(skb));
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if (err) {
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if (!(flags & MSG_PEEK))
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skb_queue_head(&sk->sk_receive_queue, skb);
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return err;
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}
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/* Mark read part of skb as used */
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if (!(flags & MSG_PEEK)) {
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skb_pull(skb, copied);
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@ -1316,7 +1387,7 @@ static void iucv_callback_txdone(struct iucv_path *path,
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spin_lock_irqsave(&list->lock, flags);
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while (list_skb != (struct sk_buff *)list) {
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if (!memcmp(&msg->tag, list_skb->cb, 4)) {
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if (!memcmp(&msg->tag, CB_TAG(list_skb), CB_TAG_LEN)) {
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this = list_skb;
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break;
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}
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