msgb: msgb_get() is supposed to get bytes from END, msgb_pull() from HEAD
msgb_get() has been wrong all the time, despite the documentation being
correct. If you've used the broken msgb_get() before, you have to
change your code now, sorry.
diff --git a/include/osmocom/core/msgb.h b/include/osmocom/core/msgb.h
index 5457a07..36c7c0f 100644
--- a/include/osmocom/core/msgb.h
+++ b/include/osmocom/core/msgb.h
@@ -72,6 +72,7 @@
extern void msgb_enqueue(struct llist_head *queue, struct msgb *msg);
extern struct msgb *msgb_dequeue(struct llist_head *queue);
extern void msgb_reset(struct msgb *m);
+uint16_t msgb_length(const struct msgb *msg);
#ifdef MSGB_DEBUG
#include <osmocom/core/panic.h>
@@ -226,8 +227,11 @@
*/
static inline unsigned char *msgb_get(struct msgb *msgb, unsigned int len)
{
- unsigned char *tmp = msgb->data;
- msgb->data += len;
+ unsigned char *tmp = msgb->data - len;
+ if (msgb_length(msgb) < len)
+ MSGB_ABORT(msgb, "msgb too small to get %u (len %u)\n",
+ len, msgb_length(msgb));
+ msgb->tail -= len;
msgb->len -= len;
return tmp;
}
@@ -295,6 +299,34 @@
return msgb->data += len;
}
+/*! \brief remove uint8 from front of message
+ * \param[in] msgb message buffer
+ * \returns 8bit value taken from end of msgb
+ */
+static inline uint8_t msgb_pull_u8(struct msgb *msgb)
+{
+ uint8_t *space = msgb_pull(msgb, 1);
+ return space[0];
+}
+/*! \brief remove uint16 from front of message
+ * \param[in] msgb message buffer
+ * \returns 16bit value taken from end of msgb
+ */
+static inline uint16_t msgb_pull_u16(struct msgb *msgb)
+{
+ uint8_t *space = msgb_pull(msgb, 2);
+ return space[0] << 8 | space[1];
+}
+/*! \brief remove uint32 from front of message
+ * \param[in] msgb message buffer
+ * \returns 32bit value taken from end of msgb
+ */
+static inline uint32_t msgb_pull_u32(struct msgb *msgb)
+{
+ uint8_t *space = msgb_pull(msgb, 4);
+ return space[0] << 24 | space[1] << 16 | space[2] << 8 | space[3];
+}
+
/*! \brief Increase headroom of empty msgb, reducing the tailroom
* \param[in] msg message buffer
* \param[in] len amount of extra octets to be reserved as headroom
@@ -362,7 +394,6 @@
/* non inline functions to ease binding */
uint8_t *msgb_data(const struct msgb *msg);
-uint16_t msgb_length(const struct msgb *msg);
void msgb_set_talloc_ctx(void *ctx);
/*! @} */