network: Add net_buffer::buffer_flags field.

Does not actually break ABI since net_buffer had 3 bytes of padding
remaining unused.

Add the first two constants for this field: L3/L4_CHECKSUM_VALID.
These will indicate when the checksum of the packet is known to be
valid (good/correct).

Change-Id: I155b3ea51d1093e229677cb788a007560ddbd428
Reviewed-on: https://review.haiku-os.org/c/haiku/+/7916
Reviewed-by: waddlesplash <[email protected]>

headers/private/net/net_buffer.h

@@ -16,6 +16,12 @@
 #define NET_BUFFER_MODULE_NAME "network/stack/buffer/v1"
 
 
+enum net_buffer_flags {
+	NET_BUFFER_L3_CHECKSUM_VALID = (1 << 0),
+	NET_BUFFER_L4_CHECKSUM_VALID = (1 << 1),
+};
+
+
 typedef struct net_buffer {
 	struct list_link		link;
 
@@ -35,6 +41,7 @@ typedef struct net_buffer {
 	uint32					msg_flags;
 	uint32					size;
 	uint8					protocol;
+	uint16					buffer_flags;
 } net_buffer;
 
 struct ancillary_data_container;

src/add-ons/kernel/network/stack/net_buffer.cpp

@@ -609,9 +609,10 @@ dump_buffer(net_buffer* _buffer)
 {
 	net_buffer_private* buffer = (net_buffer_private*)_buffer;
 
-	dprintf("buffer %p, size %" B_PRIu32 ", msg_flags %" B_PRIx32 ", stored header "
-		"%" B_PRIuSIZE ", interface address %p\n", buffer, buffer->size,
-		buffer->msg_flags, buffer->stored_header_length, buffer->interface_address);
+	dprintf("buffer %p, size %" B_PRIu32 ", msg_flags %" B_PRIx32 ", buffer_flags %" B_PRIx16
+		", stored header %" B_PRIuSIZE ", interface address %p\n", buffer, buffer->size,
+		buffer->msg_flags, buffer->buffer_flags, buffer->stored_header_length,
+		buffer->interface_address);
 
 	dump_address("source", buffer->source, buffer->interface_address);
 	dump_address("destination", buffer->destination, buffer->interface_address);
@@ -1074,6 +1075,7 @@ copy_metadata(net_buffer* destination, const net_buffer* source)
 		min_c(source->destination->sa_len, sizeof(sockaddr_storage)));
 
 	destination->msg_flags = source->msg_flags;
+	destination->buffer_flags = source->buffer_flags;
 	destination->interface_address = source->interface_address;
 	if (destination->interface_address != NULL)
 		((InterfaceAddress*)destination->interface_address)->AcquireReference();
@@ -1127,6 +1129,7 @@ create_buffer(size_t headerSpace)
 	buffer->interface_address = NULL;
 	buffer->offset = 0;
 	buffer->msg_flags = 0;
+	buffer->buffer_flags = 0;
 	buffer->size = 0;
 
 	CHECK_BUFFER(buffer);