diff options
| -rw-r--r-- | include/osmocom/core/msgb.h | 3 | ||||
| -rw-r--r-- | src/msgb.c | 91 |
2 files changed, 94 insertions, 0 deletions
diff --git a/include/osmocom/core/msgb.h b/include/osmocom/core/msgb.h index 644a6391..9ffc64ef 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> @@ -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 |