[PATCH 3/6] msgb: Add msgb_test_invariant function

This adds a function that verifies whether a mgsb is consistent. Sponsored-by: On-Waves ehf --- include/osmocom/core/msgb.h | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) diff --git a/include/osmocom/core/msgb.h b/include/osmocom/core/msgb.h index 21e363a..2bf4ac5 100644 --- a/include/osmocom/core/msgb.h +++ b/include/osmocom/core/msgb.h @@ -77,6 +77,7 @@ extern const char *msgb_hexdump(const struct msgb *msg); extern int msgb_resize_area(struct msgb *msg, uint8_t *area, size_t old_size, size_t new_size); extern struct msgb *msgb_copy(const struct msgb *msg, const char *name); +static int msgb_test_invariant(const struct msgb *msg) __attribute__((pure)); #ifdef MSGB_DEBUG #include <osmocom/core/panic.h> @@ -412,6 +413,45 @@ static inline struct msgb *msgb_alloc_headroom(int size, int headroom, return msg; } +/*! \brief Check a message buffer for consistency + * \param[in] msg message buffer + * \returns 0 (false) if inconsistent, != 0 (true) otherwise + */ +static inline int msgb_test_invariant(const struct msgb *msg) +{ + const unsigned char *lbound; + if (!msg || !msg->data || !msg->tail || + (msg->data + msg->len != msg->tail) || + (msg->data < msg->head) || + (msg->tail > msg->head + msg->data_len)) + return 0; + + lbound = msg->head; + + if (msg->l1h) { + if (msg->l1h < lbound) + return 0; + lbound = msg->l1h; + } + if (msg->l2h) { + if (msg->l2h < lbound) + return 0; + lbound = msg->l2h; + } + if (msg->l3h) { + if (msg->l3h < lbound) + return 0; + lbound = msg->l3h; + } + if (msg->l4h) { + if (msg->l4h < lbound) + return 0; + lbound = msg->l4h; + } + + return lbound <= msg->head + msg->data_len; +} + /* non inline functions to ease binding */ uint8_t *msgb_data(const struct msgb *msg); -- 1.9.1