4  * SPDX-License-Identifier: Apache-2.0
52  *  If an entire payload (e.g., IPv6) datagram fits within a single 802.15.4
54  *  a fragmentation header.  If the datagram does not fit within a single
61  *  Functionality is comprised of link-local IPv6 addresses and stateless
62  *  IPv6 address autoconfiguration, Neighbor Discovery, and header compression
64  *  LE's link-layer fragmentation support.
70  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
72  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
76  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
78  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
80  *  +-+-+-+-+-+-+-+-+
100 	uint8_t pos = frag->len;  in set_up_frag_hdr()
105 		frag->data[pos] = NET_6LO_DISPATCH_FRAG1;  in set_up_frag_hdr()
108 		frag->data[pos] = NET_6LO_DISPATCH_FRAGN;  in set_up_frag_hdr()
111 	set_datagram_size(frag->data + pos, size);  in set_up_frag_hdr()
114 	set_datagram_tag(frag->data + pos, datagram_tag);  in set_up_frag_hdr()
118 		frag->data[pos] = offset;  in set_up_frag_hdr()
124 	uint8_t capacity = frag->size - frag->len;  in calc_payload_capacity()
132 	uint8_t remainder = ctx->buf->len - (ctx->pos - ctx->buf->data);  in copy_data()
135 	memcpy(frame_buf->data + frame_buf->len, ctx->pos, move);  in copy_data()
143 	uint8_t remainder = (ctx->buf->len - (ctx->pos - ctx->buf->data));  in update_fragment_ctx()
147 		ctx->buf = ctx->buf->frags;  in update_fragment_ctx()
148 		if (ctx->buf) {  in update_fragment_ctx()
149 			ctx->pos = ctx->buf->data;  in update_fragment_ctx()
152 		ctx->pos += moved;  in update_fragment_ctx()
157  *  ch  : compressed (IPv6) header(s)
158  *  fh  : fragment header (dispatch + size + tag + [offset])
159  *  p   : payload (first fragment holds IPv6 hdr as payload)
173  *  Space in every fragment is because fragment payload should be multiple
185 	set_up_frag_hdr(frame_buf, ctx->pkt_size, ctx->offset);  in ieee802154_6lo_fragment()
188 	ctx->processed += capacity;  in ieee802154_6lo_fragment()
190 	bool is_first_frag = !ctx->offset;  in ieee802154_6lo_fragment()
195 			capacity -= ctx->hdr_diff;  in ieee802154_6lo_fragment()
197 			/* Adding IPv6 dispatch header */  in ieee802154_6lo_fragment()
202 	while (capacity && ctx->buf) {  in ieee802154_6lo_fragment()
206 		capacity -= moved;  in ieee802154_6lo_fragment()
209 	ctx->offset = ctx->processed >> 3;  in ieee802154_6lo_fragment()
211 	return ctx->buf;  in ieee802154_6lo_fragment()
236 		NET_ERR("Could not get IPv6 header");  in update_protocol_header_lengths()
241 	ipv6->len = htons(size - NET_IPV6H_LEN);  in update_protocol_header_lengths()
245 	if (ipv6->nexthdr == IPPROTO_UDP) {  in update_protocol_header_lengths()
251 			udp->len = htons(size - NET_IPV6H_LEN);  in update_protocol_header_lengths()
254 			NET_ERR("Could not get UDP header");  in update_protocol_header_lengths()
289 	if (fcache->pkt) {  in reass_timeout()
290 		net_pkt_unref(fcache->pkt);  in reass_timeout()
293 	fcache->pkt = NULL;  in reass_timeout()
294 	fcache->size = 0U;  in reass_timeout()
295 	fcache->tag = 0U;  in reass_timeout()
296 	fcache->used = false;  in reass_timeout()
347 	if (get_datagram_type(frag->data) == NET_6LO_DISPATCH_FRAG1) {  in fragment_append()
351 		frag->frags = pkt->buffer;  in fragment_append()
352 		pkt->buffer = frag;  in fragment_append()
365 	frag = pkt->buffer;  in fragment_cached_pkt_len()
369 		if (get_datagram_type(frag->data) == NET_6LO_DISPATCH_FRAG1) {  in fragment_cached_pkt_len()
373 		len += frag->len - frag_hdr_len;  in fragment_cached_pkt_len()
375 		frag = frag->frags;  in fragment_cached_pkt_len()
378 	/* 6lo assumes that fragment header has been removed,  in fragment_cached_pkt_len()
381 	data = pkt->buffer->data;  in fragment_cached_pkt_len()
382 	pkt->buffer->data += NET_6LO_FRAG1_HDR_LEN;  in fragment_cached_pkt_len()
386 	pkt->buffer->data = data;  in fragment_cached_pkt_len()
397 	if (get_datagram_type(frag->data) == NET_6LO_DISPATCH_FRAG1) {  in fragment_offset()
401 	return ((uint16_t)frag->data[NET_FRAG_OFFSET_POS] << 3);  in fragment_offset()
409 	current = pkt->buffer;  in fragment_move_back()
414 				prev->frags = frag;  in fragment_move_back()
417 			frag->frags = current;  in fragment_move_back()
422 		current = current->frags;  in fragment_move_back()
430 	frag = pkt->buffer;  in fragment_remove_headers()
434 		if (get_datagram_type(frag->data) == NET_6LO_DISPATCH_FRAG1) {  in fragment_remove_headers()
438 		memmove(frag->data, frag->data + frag_hdr_len, frag->len - frag_hdr_len);  in fragment_remove_headers()
439 		frag->len -= frag_hdr_len;  in fragment_remove_headers()
441 		frag = frag->frags;  in fragment_remove_headers()
450 	current = pkt->buffer;  in fragment_reconstruct_packet()
453 		next = current->frags;  in fragment_reconstruct_packet()
470 	return (get_datagram_type(pkt->buffer->data) == NET_6LO_DISPATCH_FRAG1);  in fragment_packet_valid()
476  *  Remove the fragmentation header and uncompress IPv6 and related headers.
490 	frag = pkt->buffer;  in fragment_add_to_cache()
491 	type = get_datagram_type(frag->data);  in fragment_add_to_cache()
493 	if ((type == NET_6LO_DISPATCH_FRAG1 && frag->len < NET_6LO_FRAG1_HDR_LEN) ||  in fragment_add_to_cache()
494 	    (type == NET_6LO_DISPATCH_FRAGN && frag->len < NET_6LO_FRAGN_HDR_LEN)) {  in fragment_add_to_cache()
495 		NET_ERR("Fragment too short (%u): fragment dropped", frag->len);  in fragment_add_to_cache()
500 	size = get_datagram_size(frag->data);  in fragment_add_to_cache()
503 	tag = get_datagram_tag(frag->data + NET_6LO_FRAG_DATAGRAM_SIZE_LEN);  in fragment_add_to_cache()
508 	pkt->buffer = NULL;  in fragment_add_to_cache()
517 			pkt->buffer = frag;  in fragment_add_to_cache()
524 	fragment_append(fcache->pkt, frag);  in fragment_add_to_cache()
526 	if (fragment_cached_pkt_len(fcache->pkt) == fcache->size) {  in fragment_add_to_cache()
527 		/* All fragments received - reassemble packet. */  in fragment_add_to_cache()
531 			pkt->buffer = fcache->pkt->buffer;  in fragment_add_to_cache()
532 			fcache->pkt->buffer = NULL;  in fragment_add_to_cache()
534 			/* In case pkt == fcache->pkt, we don't want  in fragment_add_to_cache()
537 			fcache->pkt = NULL;  in fragment_add_to_cache()
550 			NET_ERR("Invalid 6LoWPAN header: packet dropped");  in fragment_add_to_cache()
575 	if (!pkt || !pkt->buffer) {  in ieee802154_6lo_reassemble()
576 		NET_WARN("Empty payload: packet dropped");  in ieee802154_6lo_reassemble()
580 	if (get_datagram_type(pkt->buffer->data) >= NET_6LO_DISPATCH_FRAG1) {  in ieee802154_6lo_reassemble()
583 		NET_DBG("No frag dispatch (%02x)", pkt->buffer->data[0]);  in ieee802154_6lo_reassemble()
589 		NET_ERR("Invalid header: packet dropped");  in ieee802154_6lo_reassemble()