From 44b1e6b5f9a93cc2ba024e09cf137d5f1b5f8426 Mon Sep 17 00:00:00 2001 From: Hendrik Brueckner Date: Tue, 21 Apr 2009 23:26:24 +0000 Subject: [PATCH] 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 Signed-off-by: Ursula Braun Signed-off-by: David S. Miller --- include/net/iucv/af_iucv.h | 3 ++ net/iucv/af_iucv.c | 79 ++++++++++++++++++++++++++++++++++++-- 2 files changed, 78 insertions(+), 4 deletions(-) diff --git a/include/net/iucv/af_iucv.h b/include/net/iucv/af_iucv.h index 78a72764aef..b57739e49dc 100644 --- a/include/net/iucv/af_iucv.h +++ b/include/net/iucv/af_iucv.h @@ -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; diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c index 5fc077ee583..47c5c8d3703 100644 --- a/net/iucv/af_iucv.c +++ b/net/iucv/af_iucv.c @@ -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; }