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Diffstat (limited to 'net/tipc/msg.c')
-rw-r--r--net/tipc/msg.c102
1 files changed, 102 insertions, 0 deletions
diff --git a/net/tipc/msg.c b/net/tipc/msg.c
index e02afc96edd7..4093b4c94d26 100644
--- a/net/tipc/msg.c
+++ b/net/tipc/msg.c
@@ -144,6 +144,108 @@ out_free:
return 0;
}
+
+/**
+ * tipc_msg_build2 - create buffer chain containing specified header and data
+ * @mhdr: Message header, to be prepended to data
+ * @iov: User data
+ * @offset: Posision in iov to start copying from
+ * @dsz: Total length of user data
+ * @pktmax: Max packet size that can be used
+ * @chain: Buffer or chain of buffers to be returned to caller
+ * Returns message data size or errno: -ENOMEM, -EFAULT
+ */
+int tipc_msg_build2(struct tipc_msg *mhdr, struct iovec const *iov,
+ int offset, int dsz, int pktmax , struct sk_buff **chain)
+{
+ int mhsz = msg_hdr_sz(mhdr);
+ int msz = mhsz + dsz;
+ int pktno = 1;
+ int pktsz;
+ int pktrem = pktmax;
+ int drem = dsz;
+ struct tipc_msg pkthdr;
+ struct sk_buff *buf, *prev;
+ char *pktpos;
+ int rc;
+
+ msg_set_size(mhdr, msz);
+
+ /* No fragmentation needed? */
+ if (likely(msz <= pktmax)) {
+ buf = tipc_buf_acquire(msz);
+ *chain = buf;
+ if (unlikely(!buf))
+ return -ENOMEM;
+ skb_copy_to_linear_data(buf, mhdr, mhsz);
+ pktpos = buf->data + mhsz;
+ if (!dsz || !memcpy_fromiovecend(pktpos, iov, offset, dsz))
+ return dsz;
+ rc = -EFAULT;
+ goto error;
+ }
+
+ /* Prepare reusable fragment header */
+ tipc_msg_init(&pkthdr, MSG_FRAGMENTER, FIRST_FRAGMENT,
+ INT_H_SIZE, msg_destnode(mhdr));
+ msg_set_size(&pkthdr, pktmax);
+ msg_set_fragm_no(&pkthdr, pktno);
+
+ /* Prepare first fragment */
+ *chain = buf = tipc_buf_acquire(pktmax);
+ if (!buf)
+ return -ENOMEM;
+ pktpos = buf->data;
+ skb_copy_to_linear_data(buf, &pkthdr, INT_H_SIZE);
+ pktpos += INT_H_SIZE;
+ pktrem -= INT_H_SIZE;
+ skb_copy_to_linear_data_offset(buf, INT_H_SIZE, mhdr, mhsz);
+ pktpos += mhsz;
+ pktrem -= mhsz;
+
+ do {
+ if (drem < pktrem)
+ pktrem = drem;
+
+ if (memcpy_fromiovecend(pktpos, iov, offset, pktrem)) {
+ rc = -EFAULT;
+ goto error;
+ }
+ drem -= pktrem;
+ offset += pktrem;
+
+ if (!drem)
+ break;
+
+ /* Prepare new fragment: */
+ if (drem < (pktmax - INT_H_SIZE))
+ pktsz = drem + INT_H_SIZE;
+ else
+ pktsz = pktmax;
+ prev = buf;
+ buf = tipc_buf_acquire(pktsz);
+ if (!buf) {
+ rc = -ENOMEM;
+ goto error;
+ }
+ prev->next = buf;
+ msg_set_type(&pkthdr, FRAGMENT);
+ msg_set_size(&pkthdr, pktsz);
+ msg_set_fragm_no(&pkthdr, ++pktno);
+ skb_copy_to_linear_data(buf, &pkthdr, INT_H_SIZE);
+ pktpos = buf->data + INT_H_SIZE;
+ pktrem = pktsz - INT_H_SIZE;
+
+ } while (1);
+
+ msg_set_type(buf_msg(buf), LAST_FRAGMENT);
+ return dsz;
+error:
+ kfree_skb_list(*chain);
+ *chain = NULL;
+ return rc;
+}
+
/**
* tipc_msg_bundle(): Append contents of a buffer to tail of an existing one
* @bbuf: the existing buffer ("bundle")