These functions originate from openbsc/src/gprs but are generic
msgb helper functions.
msgb_copy: This function allocates a new msgb, copies the data
buffer of msg, and adjusts the pointers (incl. l1h-l4h)
accordingly.
msgb_resize_area:
This resizes a sub area of the msgb data and adjusts the
pointers (incl. l1h-l4h) accordingly.
Sponsored-by: On-Waves ehf
---
include/osmocom/core/msgb.h | 3 ++
src/msgb.c | 91 +++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 94 insertions(+)
diff --git a/include/osmocom/core/msgb.h b/include/osmocom/core/msgb.h
index 644a639..9ffc64e 100644
--- a/include/osmocom/core/msgb.h
+++ b/include/osmocom/core/msgb.h
@@ -74,6 +74,9 @@ extern struct msgb *msgb_dequeue(struct llist_head *queue);
extern void msgb_reset(struct msgb *m);
uint16_t msgb_length(const struct msgb *msg);
extern const char *msgb_hexdump(const struct msgb *msg);
+extern int msgb_resize_area(struct msgb *msg, uint8_t *area,
+ int old_size, int new_size);
+extern struct msgb *msgb_copy(const struct msgb *msg, const char *name);
#ifdef MSGB_DEBUG
#include <osmocom/core/panic.h>
diff --git a/src/msgb.c b/src/msgb.c
index b2fe1d2..3132644 100644
--- a/src/msgb.c
+++ b/src/msgb.c
@@ -153,6 +153,97 @@ void msgb_set_talloc_ctx(void *ctx)
tall_msgb_ctx = ctx;
}
+/*! \brief Copy an msgb.
+ *
+ * This function allocates a new msgb, copies the data buffer of msg,
+ * and adjusts the pointers (incl l1h-l4h) accordingly. The cb part
+ * is not copied.
+ * \param[in] msg The old msgb object
+ * \param[in] name Human-readable name to be associated with msgb
+ */
+struct msgb *msgb_copy(const struct msgb *msg, const char *name)
+{
+ struct msgb *new_msg;
+
+ new_msg = msgb_alloc(msg->data_len, name);
+ if (!new_msg)
+ return NULL;
+
+ /* copy data */
+ memcpy(new_msg->_data, msg->_data, new_msg->data_len);
+
+ /* copy header */
+ new_msg->len = msg->len;
+ new_msg->data += msg->data - msg->_data;
+ new_msg->head += msg->head - msg->_data;
+ new_msg->tail += msg->tail - msg->_data;
+
+ if (msg->l1h)
+ new_msg->l1h = new_msg->_data + (msg->l1h - msg->_data);
+ if (msg->l2h)
+ new_msg->l2h = new_msg->_data + (msg->l2h - msg->_data);
+ if (msg->l3h)
+ new_msg->l3h = new_msg->_data + (msg->l3h - msg->_data);
+ if (msg->l4h)
+ new_msg->l4h = new_msg->_data + (msg->l4h - msg->_data);
+
+ return new_msg;
+}
+
+/*! \brief Resize an area within an msgb
+ *
+ * This resizes a sub area of the msgb data and adjusts the pointers (incl
+ * l1h-l4h) accordingly. The cb part is not updated. If the area is extended,
+ * the contents of the extension is undefined. The complete sub area must be a
+ * part of [data,tail].
+ *
+ * \param[inout] msg The msgb object
+ * \param[in] area A pointer to the sub-area
+ * \param[in] old_size The old size of the sub-area
+ * \param[in] new_size The new size of the sub-area
+ * \returns 0 on success, -1 if there is not enough space to extend the area
+ */
+int msgb_resize_area(struct msgb *msg, uint8_t *area,
+ int old_size, int new_size)
+{
+ int rc;
+ uint8_t *post_start = area + old_size;
+ int pre_len = area - msg->data;
+ int post_len = msg->len - old_size - pre_len;
+ int delta_size = new_size - old_size;
+
+ if (old_size < 0 || new_size < 0)
+ MSGB_ABORT(msg, "Negative sizes are not allowed\n");
+ if (area < msg->data || post_start > msg->tail)
+ MSGB_ABORT(msg, "Sub area is not fully contained in the msg
data\n");
+
+ if (delta_size == 0)
+ return 0;
+
+ if (delta_size > 0) {
+ rc = msgb_trim(msg, msg->len + delta_size);
+ if (rc < 0)
+ return rc;
+ }
+
+ memmove(area + new_size, area + old_size, post_len);
+
+ if (msg->l1h >= post_start)
+ msg->l1h += delta_size;
+ if (msg->l2h >= post_start)
+ msg->l2h += delta_size;
+ if (msg->l3h >= post_start)
+ msg->l3h += delta_size;
+ if (msg->l4h >= post_start)
+ msg->l4h += delta_size;
+
+ if (delta_size < 0)
+ msgb_trim(msg, msg->len + delta_size);
+
+ return 0;
+}
+
+
/*! \brief Return a (static) buffer containing a hexdump of the msg
* \param[in] msg message buffer
* \returns a pointer to a static char array
--
1.9.1
