Provide a temporary variable of the wanted type to store
the header if the memory in the iovec array is not contiguous.
Signed-off-by: Laurent Vivier
---
iov.c | 53 ++++++++++++++++++++++++++++++++++++++++++++---------
iov.h | 35 +++++++++++++++++++++--------------
tcp_buf.c | 2 +-
3 files changed, 66 insertions(+), 24 deletions(-)
diff --git a/iov.c b/iov.c
index 9a91eb63026a..d20fbb854933 100644
--- a/iov.c
+++ b/iov.c
@@ -109,7 +109,7 @@ size_t iov_from_buf(const struct iovec *iov, size_t iov_cnt,
*
* Return: the number of bytes successfully copied.
*/
-/* cppcheck-suppress unusedFunction */
+/* cppcheck-suppress [staticFunction] */
size_t iov_to_buf(const struct iovec *iov, size_t iov_cnt,
size_t offset, void *buf, size_t bytes)
{
@@ -127,6 +127,7 @@ size_t iov_to_buf(const struct iovec *iov, size_t iov_cnt,
/* copying data */
for (copied = 0; copied < bytes && i < iov_cnt; i++) {
size_t len = MIN(iov[i].iov_len - offset, bytes - copied);
+ ASSERT(iov[i].iov_base);
memcpy((char *)buf + copied, (char *)iov[i].iov_base + offset,
len);
copied += len;
@@ -208,7 +209,7 @@ bool iov_drop_header(struct iov_tail *tail, size_t len)
}
/**
- * iov_peek_header_() - Get pointer to a header from an IOV tail
+ * iov_check_header() - Check if a header can be accessed
* @tail: IOV tail to get header from
* @len: Length of header to get, in bytes
* @align: Required alignment of header, in bytes
@@ -219,8 +220,7 @@ bool iov_drop_header(struct iov_tail *tail, size_t len)
* overruns the IO vector, is not contiguous or doesn't have the
* requested alignment.
*/
-/* cppcheck-suppress [staticFunction,unmatchedSuppression] */
-void *iov_peek_header_(struct iov_tail *tail, size_t len, size_t align)
+static void *iov_check_header(struct iov_tail *tail, size_t len, size_t align)
{
char *p;
@@ -240,27 +240,62 @@ void *iov_peek_header_(struct iov_tail *tail, size_t len, size_t align)
return p;
}
+/**
+ * iov_peek_header_() - Get pointer to a header from an IOV tail
+ * @tail: IOV tail to get header from
+ * @v: Temporary memory to use if the memory in @tail
+ * is discontinuous
+ * @len: Length of header to get, in bytes
+ * @align: Required alignment of header, in bytes
+ *
+ * @tail may be pruned, but will represent the same bytes as before.
+ *
+ * Return: pointer to the first @len logical bytes of the tail, or to
+ * a copy if that overruns the IO vector, is not contiguous or
+ * doesn't have the requested alignment. NULL if that overruns the
+ * IO vector.
+ */
+/* cppcheck-suppress [staticFunction,unmatchedSuppression] */
+void *iov_peek_header_(struct iov_tail *tail, void *v, size_t len, size_t align)
+{
+ char *p = iov_check_header(tail, len, align);
+ size_t l;
+
+ if (p)
+ return p;
+
+ l = iov_to_buf(tail->iov, tail->cnt, tail->off, v, len);
+ if (l != len)
+ return NULL;
+
+ return v;
+}
+
/**
* iov_remove_header_() - Remove a header from an IOV tail
* @tail: IOV tail to remove header from (modified)
+ * @v: Temporary memory to use if the memory in @tail
+ * is discontinuous
* @len: Length of header to remove, in bytes
* @align: Required alignment of header, in bytes
*
* On success, @tail is updated so that it longer includes the bytes of the
* returned header.
*
- * Return: pointer to the first @len logical bytes of the tail, NULL if that
- * overruns the IO vector, is not contiguous or doesn't have the
- * requested alignment.
+ * Return: pointer to the first @len logical bytes of the tail, or to
+ * a copy if that overruns the IO vector, is not contiguous or
+ * doesn't have the requested alignment. NULL if that overruns the
+ * IO vector.
*/
-void *iov_remove_header_(struct iov_tail *tail, size_t len, size_t align)
+void *iov_remove_header_(struct iov_tail *tail, void *v, size_t len, size_t align)
{
- char *p = iov_peek_header_(tail, len, align);
+ char *p = iov_peek_header_(tail, v, len, align);
if (!p)
return NULL;
tail->off = tail->off + len;
+
return p;
}
diff --git a/iov.h b/iov.h
index c94fabe1eb43..1821b40b1cb5 100644
--- a/iov.h
+++ b/iov.h
@@ -73,38 +73,45 @@ struct iov_tail {
bool iov_tail_prune(struct iov_tail *tail);
size_t iov_tail_size(struct iov_tail *tail);
bool iov_drop_header(struct iov_tail *tail, size_t len);
-void *iov_peek_header_(struct iov_tail *tail, size_t len, size_t align);
-void *iov_remove_header_(struct iov_tail *tail, size_t len, size_t align);
+void *iov_peek_header_(struct iov_tail *tail, void *v, size_t len, size_t align);
+void *iov_remove_header_(struct iov_tail *tail, void *v, size_t len, size_t align);
ssize_t iov_tail_clone(struct iovec *dst_iov, size_t dst_iov_cnt,
struct iov_tail *tail);
/**
* IOV_PEEK_HEADER() - Get typed pointer to a header from an IOV tail
* @tail_: IOV tail to get header from
- * @type_: Data type of the header
+ * @var_: Temporary buffer of the type of the header to use if
+ * the memory in the iovec array is not contiguous.
*
* @tail_ may be pruned, but will represent the same bytes as before.
*
- * Return: pointer of type (@type_ *) located at the start of @tail_, NULL if
- * we can't get a contiguous and aligned pointer.
+ * Return: pointer of type (@type_ *) located at the start of @tail_
+ * or to @var_ if iovec memory is not contiguous, NULL if
+ * that overruns the iovec.
*/
-#define IOV_PEEK_HEADER(tail_, type_) \
- ((type_ *)(iov_peek_header_((tail_), \
- sizeof(type_), __alignof__(type_))))
+
+#define IOV_PEEK_HEADER(tail_, var_) \
+ ((__typeof__(var_) *)(iov_peek_header_((tail_), &(var_), \
+ sizeof(var_), \
+ __alignof__(var_))))
/**
* IOV_REMOVE_HEADER() - Remove and return typed header from an IOV tail
* @tail_: IOV tail to remove header from (modified)
- * @type_: Data type of the header to remove
+ * @var_: Temporary buffer of the type of the header to use if
+ * the memory in the iovec array is not contiguous.
*
* On success, @tail_ is updated so that it longer includes the bytes of the
* returned header.
*
- * Return: pointer of type (@type_ *) located at the old start of @tail_, NULL
- * if we can't get a contiguous and aligned pointer.
+ * Return: pointer of type (@type_ *) located at the start of @tail_
+ * or to @var_ if iovec memory is not contiguous, NULL if
+ * that overruns the iovec.
*/
-#define IOV_REMOVE_HEADER(tail_, type_) \
- ((type_ *)(iov_remove_header_((tail_), \
- sizeof(type_), __alignof__(type_))))
+
+#define IOV_REMOVE_HEADER(tail_, var_) \
+ ((__typeof__(var_) *)(iov_remove_header_((tail_), &(var_), \
+ sizeof(var_), __alignof__(var_))))
#endif /* IOVEC_H */
diff --git a/tcp_buf.c b/tcp_buf.c
index d1fca676c9a7..bc898de86919 100644
--- a/tcp_buf.c
+++ b/tcp_buf.c
@@ -160,7 +160,7 @@ static void tcp_l2_buf_fill_headers(const struct tcp_tap_conn *conn,
uint32_t seq, bool no_tcp_csum)
{
struct iov_tail tail = IOV_TAIL(&iov[TCP_IOV_PAYLOAD], 1, 0);
- struct tcphdr *th = IOV_REMOVE_HEADER(&tail, struct tcphdr);
+ struct tcphdr th_storage, *th = IOV_REMOVE_HEADER(&tail, th_storage);
struct tap_hdr *taph = iov[TCP_IOV_TAP].iov_base;
const struct flowside *tapside = TAPFLOW(conn);
const struct in_addr *a4 = inany_v4(&tapside->oaddr);
--
2.49.0