net: buf: Add locking or sealing or typing mechanism

Once a `type_id` has been set, all actions made through the API (R.I.P code that casts buf->data) will fail. This is meant to add typing information to net_buf's as they go through the layers of networking stacks. My understanding is that the actual net stack uses packets which are typed better than net bufs. Maybe that's what we should do instead. Signed-off-by: Jonathan Rico <jonathan.rico@nordicsemi.no>
jori-nordic · Aug 1, 2024 · 2071914 · 2071914
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diff --git a/include/zephyr/net/buf.h b/include/zephyr/net/buf.h
@@ -1022,6 +1022,9 @@ struct net_buf {
 	/** Size of user data on this buffer */
 	uint8_t user_data_size;
 
+	/** Now with more magic */
+	uintptr_t type_id;
+
 	/** Union for convenience access to the net_buf_simple members, also
 	 * preserving the old API.
 	 */
@@ -1623,6 +1626,7 @@ static inline void net_buf_reserve(struct net_buf *buf, size_t reserve)
  */
 static inline void *net_buf_add(struct net_buf *buf, size_t len)
 {
+	__ASSERT_NO_MSG(buf->type_id == 0);
 	return net_buf_simple_add(&buf->b, len);
 }
 
@@ -1641,6 +1645,7 @@ static inline void *net_buf_add(struct net_buf *buf, size_t len)
 static inline void *net_buf_add_mem(struct net_buf *buf, const void *mem,
 				    size_t len)
 {
+	__ASSERT_NO_MSG(buf->type_id == 0);
 	return net_buf_simple_add_mem(&buf->b, mem, len);
 }
 
@@ -1657,6 +1662,7 @@ static inline void *net_buf_add_mem(struct net_buf *buf, const void *mem,
  */
 static inline uint8_t *net_buf_add_u8(struct net_buf *buf, uint8_t val)
 {
+	__ASSERT_NO_MSG(buf->type_id == 0);
 	return net_buf_simple_add_u8(&buf->b, val);
 }
 
@@ -1852,6 +1858,7 @@ static inline void net_buf_add_be64(struct net_buf *buf, uint64_t val)
  */
 static inline void *net_buf_remove_mem(struct net_buf *buf, size_t len)
 {
+	__ASSERT_NO_MSG(buf->type_id == 0);
 	return net_buf_simple_remove_mem(&buf->b, len);
 }
 
@@ -1867,6 +1874,7 @@ static inline void *net_buf_remove_mem(struct net_buf *buf, size_t len)
  */
 static inline uint8_t net_buf_remove_u8(struct net_buf *buf)
 {
+	__ASSERT_NO_MSG(buf->type_id == 0);
 	return net_buf_simple_remove_u8(&buf->b);
 }
 
@@ -1882,6 +1890,7 @@ static inline uint8_t net_buf_remove_u8(struct net_buf *buf)
  */
 static inline uint16_t net_buf_remove_le16(struct net_buf *buf)
 {
+	__ASSERT_NO_MSG(buf->type_id == 0);
 	return net_buf_simple_remove_le16(&buf->b);
 }
 
@@ -1897,6 +1906,7 @@ static inline uint16_t net_buf_remove_le16(struct net_buf *buf)
  */
 static inline uint16_t net_buf_remove_be16(struct net_buf *buf)
 {
+	__ASSERT_NO_MSG(buf->type_id == 0);
 	return net_buf_simple_remove_be16(&buf->b);
 }
 
@@ -1912,6 +1922,7 @@ static inline uint16_t net_buf_remove_be16(struct net_buf *buf)
  */
 static inline uint32_t net_buf_remove_be24(struct net_buf *buf)
 {
+	__ASSERT_NO_MSG(buf->type_id == 0);
 	return net_buf_simple_remove_be24(&buf->b);
 }
 
@@ -1927,6 +1938,7 @@ static inline uint32_t net_buf_remove_be24(struct net_buf *buf)
  */
 static inline uint32_t net_buf_remove_le24(struct net_buf *buf)
 {
+	__ASSERT_NO_MSG(buf->type_id == 0);
 	return net_buf_simple_remove_le24(&buf->b);
 }
 
@@ -1942,6 +1954,7 @@ static inline uint32_t net_buf_remove_le24(struct net_buf *buf)
  */
 static inline uint32_t net_buf_remove_le32(struct net_buf *buf)
 {
+	__ASSERT_NO_MSG(buf->type_id == 0);
 	return net_buf_simple_remove_le32(&buf->b);
 }
 
@@ -1957,6 +1970,7 @@ static inline uint32_t net_buf_remove_le32(struct net_buf *buf)
  */
 static inline uint32_t net_buf_remove_be32(struct net_buf *buf)
 {
+	__ASSERT_NO_MSG(buf->type_id == 0);
 	return net_buf_simple_remove_be32(&buf->b);
 }
 
@@ -1972,6 +1986,7 @@ static inline uint32_t net_buf_remove_be32(struct net_buf *buf)
  */
 static inline uint64_t net_buf_remove_le40(struct net_buf *buf)
 {
+	__ASSERT_NO_MSG(buf->type_id == 0);
 	return net_buf_simple_remove_le40(&buf->b);
 }
 
@@ -1987,6 +2002,7 @@ static inline uint64_t net_buf_remove_le40(struct net_buf *buf)
  */
 static inline uint64_t net_buf_remove_be40(struct net_buf *buf)
 {
+	__ASSERT_NO_MSG(buf->type_id == 0);
 	return net_buf_simple_remove_be40(&buf->b);
 }
 
@@ -2002,6 +2018,7 @@ static inline uint64_t net_buf_remove_be40(struct net_buf *buf)
  */
 static inline uint64_t net_buf_remove_le48(struct net_buf *buf)
 {
+	__ASSERT_NO_MSG(buf->type_id == 0);
 	return net_buf_simple_remove_le48(&buf->b);
 }
 
@@ -2017,6 +2034,7 @@ static inline uint64_t net_buf_remove_le48(struct net_buf *buf)
  */
 static inline uint64_t net_buf_remove_be48(struct net_buf *buf)
 {
+	__ASSERT_NO_MSG(buf->type_id == 0);
 	return net_buf_simple_remove_be48(&buf->b);
 }
 
@@ -2032,6 +2050,7 @@ static inline uint64_t net_buf_remove_be48(struct net_buf *buf)
  */
 static inline uint64_t net_buf_remove_le64(struct net_buf *buf)
 {
+	__ASSERT_NO_MSG(buf->type_id == 0);
 	return net_buf_simple_remove_le64(&buf->b);
 }
 
@@ -2047,6 +2066,7 @@ static inline uint64_t net_buf_remove_le64(struct net_buf *buf)
  */
 static inline uint64_t net_buf_remove_be64(struct net_buf *buf)
 {
+	__ASSERT_NO_MSG(buf->type_id == 0);
 	return net_buf_simple_remove_be64(&buf->b);
 }
 
@@ -2063,6 +2083,7 @@ static inline uint64_t net_buf_remove_be64(struct net_buf *buf)
  */
 static inline void *net_buf_push(struct net_buf *buf, size_t len)
 {
+	__ASSERT_NO_MSG(buf->type_id == 0);
 	return net_buf_simple_push(&buf->b, len);
 }
 
@@ -2081,6 +2102,7 @@ static inline void *net_buf_push(struct net_buf *buf, size_t len)
 static inline void *net_buf_push_mem(struct net_buf *buf, const void *mem,
 				     size_t len)
 {
+	__ASSERT_NO_MSG(buf->type_id == 0);
 	return net_buf_simple_push_mem(&buf->b, mem, len);
 }
 
@@ -2278,6 +2300,7 @@ static inline void net_buf_push_be64(struct net_buf *buf, uint64_t val)
  */
 static inline void *net_buf_pull(struct net_buf *buf, size_t len)
 {
+	__ASSERT_NO_MSG(buf->type_id == 0);
 	return net_buf_simple_pull(&buf->b, len);
 }
 
@@ -2294,6 +2317,7 @@ static inline void *net_buf_pull(struct net_buf *buf, size_t len)
  */
 static inline void *net_buf_pull_mem(struct net_buf *buf, size_t len)
 {
+	__ASSERT_NO_MSG(buf->type_id == 0);
 	return net_buf_simple_pull_mem(&buf->b, len);
 }
 
@@ -2309,6 +2333,7 @@ static inline void *net_buf_pull_mem(struct net_buf *buf, size_t len)
  */
 static inline uint8_t net_buf_pull_u8(struct net_buf *buf)
 {
+	__ASSERT_NO_MSG(buf->type_id == 0);
 	return net_buf_simple_pull_u8(&buf->b);
 }
 
@@ -2324,6 +2349,7 @@ static inline uint8_t net_buf_pull_u8(struct net_buf *buf)
  */
 static inline uint16_t net_buf_pull_le16(struct net_buf *buf)
 {
+	__ASSERT_NO_MSG(buf->type_id == 0);
 	return net_buf_simple_pull_le16(&buf->b);
 }
 
@@ -2339,6 +2365,7 @@ static inline uint16_t net_buf_pull_le16(struct net_buf *buf)
  */
 static inline uint16_t net_buf_pull_be16(struct net_buf *buf)
 {
+	__ASSERT_NO_MSG(buf->type_id == 0);
 	return net_buf_simple_pull_be16(&buf->b);
 }
 
@@ -2354,6 +2381,7 @@ static inline uint16_t net_buf_pull_be16(struct net_buf *buf)
  */
 static inline uint32_t net_buf_pull_le24(struct net_buf *buf)
 {
+	__ASSERT_NO_MSG(buf->type_id == 0);
 	return net_buf_simple_pull_le24(&buf->b);
 }
 
@@ -2369,6 +2397,7 @@ static inline uint32_t net_buf_pull_le24(struct net_buf *buf)
  */
 static inline uint32_t net_buf_pull_be24(struct net_buf *buf)
 {
+	__ASSERT_NO_MSG(buf->type_id == 0);
 	return net_buf_simple_pull_be24(&buf->b);
 }
 
@@ -2384,6 +2413,7 @@ static inline uint32_t net_buf_pull_be24(struct net_buf *buf)
  */
 static inline uint32_t net_buf_pull_le32(struct net_buf *buf)
 {
+	__ASSERT_NO_MSG(buf->type_id == 0);
 	return net_buf_simple_pull_le32(&buf->b);
 }
 
@@ -2399,6 +2429,7 @@ static inline uint32_t net_buf_pull_le32(struct net_buf *buf)
  */
 static inline uint32_t net_buf_pull_be32(struct net_buf *buf)
 {
+	__ASSERT_NO_MSG(buf->type_id == 0);
 	return net_buf_simple_pull_be32(&buf->b);
 }
 
@@ -2414,6 +2445,7 @@ static inline uint32_t net_buf_pull_be32(struct net_buf *buf)
  */
 static inline uint64_t net_buf_pull_le40(struct net_buf *buf)
 {
+	__ASSERT_NO_MSG(buf->type_id == 0);
 	return net_buf_simple_pull_le40(&buf->b);
 }
 
@@ -2429,6 +2461,7 @@ static inline uint64_t net_buf_pull_le40(struct net_buf *buf)
  */
 static inline uint64_t net_buf_pull_be40(struct net_buf *buf)
 {
+	__ASSERT_NO_MSG(buf->type_id == 0);
 	return net_buf_simple_pull_be40(&buf->b);
 }
 

diff --git a/subsys/net/buf.c b/subsys/net/buf.c
@@ -338,6 +338,7 @@ struct net_buf *net_buf_alloc_len(struct net_buf_pool *pool, size_t size,
 	buf->flags = 0U;
 	buf->frags = NULL;
 	buf->size  = size;
+	buf->type_id = 0;
 	net_buf_reset(buf);
 
 #if defined(CONFIG_NET_BUF_POOL_USAGE)