net/sctp/sm_statefuns.c

Source file repositories/reference/linux-study-clean/net/sctp/sm_statefuns.c

File Facts

System
Linux kernel
Corpus path
net/sctp/sm_statefuns.c
Extension
.c
Size
214335 bytes
Lines
6691
Domain
Networking Core
Bucket
Sockets, Protocols, Packet Path, And Network Policy
Inferred role
Networking Core: implementation source
Status
source implementation candidate

Why This File Exists

Networking stack implementation surface: socket APIs, protocol dispatch, packet flow, routing, filtering, and network namespaces.

Dependency Surface

Detected Declarations

Annotated Snippet

if (err_chunk) {
			packet = sctp_abort_pkt_new(net, ep, asoc, arg,
					(__u8 *)(err_chunk->chunk_hdr) +
					sizeof(struct sctp_chunkhdr),
					ntohs(err_chunk->chunk_hdr->length) -
					sizeof(struct sctp_chunkhdr));

			sctp_chunk_free(err_chunk);

			if (packet) {
				sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
						SCTP_PACKET(packet));
				SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
				return SCTP_DISPOSITION_CONSUME;
			} else {
				return SCTP_DISPOSITION_NOMEM;
			}
		} else {
			return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg,
						    commands);
		}
	}

	/* Grab the INIT header.  */
	chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data;

	/* Tag the variable length parameters.  */
	chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr));

	new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC);
	if (!new_asoc)
		goto nomem;

	/* Update socket peer label if first association. */
	if (security_sctp_assoc_request(new_asoc, chunk->skb)) {
		sctp_association_free(new_asoc);
		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
	}

	if (sctp_assoc_set_bind_addr_from_ep(new_asoc,
					     sctp_scope(sctp_source(chunk)),
					     GFP_ATOMIC) < 0)
		goto nomem_init;

	/* The call, sctp_process_init(), can fail on memory allocation.  */
	if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk),
			       (struct sctp_init_chunk *)chunk->chunk_hdr,
			       GFP_ATOMIC))
		goto nomem_init;

	/* B) "Z" shall respond immediately with an INIT ACK chunk.  */

	/* If there are errors need to be reported for unknown parameters,
	 * make sure to reserve enough room in the INIT ACK for them.
	 */
	len = 0;
	if (err_chunk)
		len = ntohs(err_chunk->chunk_hdr->length) -
		      sizeof(struct sctp_chunkhdr);

	repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len);
	if (!repl)
		goto nomem_init;

	/* If there are errors need to be reported for unknown parameters,
	 * include them in the outgoing INIT ACK as "Unrecognized parameter"
	 * parameter.
	 */
	if (err_chunk) {
		/* Get the "Unrecognized parameter" parameter(s) out of the
		 * ERROR chunk generated by sctp_verify_init(). Since the
		 * error cause code for "unknown parameter" and the
		 * "Unrecognized parameter" type is the same, we can
		 * construct the parameters in INIT ACK by copying the
		 * ERROR causes over.
		 */
		unk_param = (struct sctp_unrecognized_param *)
			    ((__u8 *)(err_chunk->chunk_hdr) +
			    sizeof(struct sctp_chunkhdr));
		/* Replace the cause code with the "Unrecognized parameter"
		 * parameter type.
		 */
		sctp_addto_chunk(repl, len, unk_param);
		sctp_chunk_free(err_chunk);
	}

	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));

	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));

Annotation

Implementation Notes