packet: Add packet_data()

packet_data() gets the data range from a packet descriptor from a
given pool.

It uses iov_tail to return the packet memory.

packet_data() will be renamed to replace packet_get() later.

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

2 files changed, 47 insertions, 0 deletions

diff --git a/packet.c b/packet.c
index 98ded4e..82adc9f 100644
--- a/packet.c
+++ b/packet.c
@@ -191,6 +191,48 @@ void *packet_get_do(const struct pool *p, const size_t idx,
 }
 
 /**
+ * packet_data_do() - Get data range from packet descriptor from given pool
+ * @p:		Packet pool
+ * @idx:	Index of packet descriptor in pool
+ * @data:	IOV tail to store the address of the data (output)
+ * @func:	For tracing: name of calling function, NULL means no trace()
+ * @line:	For tracing: caller line of function call
+ *
+ * Return: false if packet index is invalid, true otherwise.
+ * 	   If something wrong with @data, don't return at all (assert).
+ */
+/* cppcheck-suppress unusedFunction */
+bool packet_data_do(const struct pool *p, size_t idx,
+		    struct iov_tail *data,
+		    const char *func, int line)
+{
+	size_t i;
+
+	ASSERT_WITH_MSG(p->count <= p->size,
+			"Corrupted pool count: %zu, size: %zu, %s:%i",
+			p->count, p->size, func, line);
+
+	if (idx >= p->count) {
+		debug("packet %zu from pool size: %zu, count: %zu, "
+		      "%s:%i", idx, p->size, p->count, func, line);
+		return false;
+	}
+
+	data->cnt = 1;
+	data->off = 0;
+	data->iov = &p->pkt[idx];
+
+	for (i = 0; i < data->cnt; i++) {
+		ASSERT_WITH_MSG(!packet_check_range(p, data->iov[i].iov_base,
+						    data->iov[i].iov_len,
+						    func, line),
+				"Corrupt packet pool, %s:%i", func, line);
+	}
+
+	return true;
+}
+
+/**
  * pool_flush() - Flush a packet pool
  * @p:		Pointer to packet pool
  */
diff --git a/packet.h b/packet.h
index af40b39..062afb9 100644
--- a/packet.h
+++ b/packet.h
@@ -39,6 +39,9 @@ void *packet_get_try_do(const struct pool *p, const size_t idx,
 void *packet_get_do(const struct pool *p, const size_t idx,
 		    size_t offset, size_t len, size_t *left,
 		    const char *func, int line);
+bool packet_data_do(const struct pool *p, const size_t idx,
+		    struct iov_tail *data,
+		    const char *func, int line);
 bool pool_full(const struct pool *p);
 void pool_flush(struct pool *p);
 
@@ -49,6 +52,8 @@ void pool_flush(struct pool *p);
 	packet_get_try_do(p, idx, offset, len, left, __func__, __LINE__)
 #define packet_get(p, idx, offset, len, left)				\
 	packet_get_do(p, idx, offset, len, left, __func__, __LINE__)
+#define packet_data(p, idx, data)					\
+	packet_data_do(p, idx, data, __func__, __LINE__)
 
 #define PACKET_POOL_DECL(_name, _size, _buf)				\
 struct _name ## _t {							\