/* Helper to create ABORT with a NO_USER_DATA error. */ struct sctp_chunk *sctp_make_abort_no_data( const struct sctp_association *asoc, const struct sctp_chunk *chunk, __u32 tsn) { struct sctp_chunk *retval; __be32 payload; retval = sctp_make_abort(asoc, chunk, sizeof(sctp_errhdr_t) + sizeof(tsn)); if (!retval) goto no_mem; /* Put the tsn back into network byte order. */ payload = htonl(tsn); sctp_init_cause(retval, SCTP_ERROR_NO_DATA, sizeof(payload)); sctp_addto_chunk(retval, sizeof(payload), (const void *)&payload); /* RFC 2960 6.4 Multi-homed SCTP Endpoints * * An endpoint SHOULD transmit reply chunks (e.g., SACK, * HEARTBEAT ACK, * etc.) to the same destination transport * address from which it * received the DATA or control chunk * to which it is replying. * * [ABORT back to where the offender came from.] */ if (chunk) retval->transport = chunk->transport; no_mem: return retval; }
/* * Appendix A: Explicit Congestion Notification: * CWR: * * RFC 2481 details a specific bit for a sender to send in the header of * its next outbound TCP segment to indicate to its peer that it has * reduced its congestion window. This is termed the CWR bit. For * SCTP the same indication is made by including the CWR chunk. * This chunk contains one data element, i.e. the TSN number that * was sent in the ECNE chunk. This element represents the lowest * TSN number in the datagram that was originally marked with the * CE bit. * * 0 1 2 3 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Chunk Type=13 | Flags=00000000| Chunk Length = 8 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Lowest TSN Number | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * * Note: The CWR is considered a Control chunk. */ struct sctp_chunk *sctp_make_cwr(const struct sctp_association *asoc, const __u32 lowest_tsn, const struct sctp_chunk *chunk) { struct sctp_chunk *retval; sctp_cwrhdr_t cwr; cwr.lowest_tsn = htonl(lowest_tsn); retval = sctp_make_control(asoc, SCTP_CID_ECN_CWR, 0, sizeof(sctp_cwrhdr_t)); if (!retval) goto nodata; retval->subh.ecn_cwr_hdr = sctp_addto_chunk(retval, sizeof(cwr), &cwr); /* RFC 2960 6.4 Multi-homed SCTP Endpoints * * An endpoint SHOULD transmit reply chunks (e.g., SACK, * HEARTBEAT ACK, * etc.) to the same destination transport * address from which it * received the DATA or control chunk * to which it is replying. * * [Report a reduced congestion window back to where the ECNE * came from.] */ if (chunk) retval->transport = chunk->transport; nodata: return retval; }
/* Make a DATA chunk for the given association from the provided * parameters. However, do not populate the data payload. */ struct sctp_chunk *sctp_make_datafrag_empty(struct sctp_association *asoc, const struct sctp_sndrcvinfo *sinfo, int data_len, __u8 flags, __u16 ssn) { struct sctp_chunk *retval; struct sctp_datahdr dp; int chunk_len; /* We assign the TSN as LATE as possible, not here when * creating the chunk. */ dp.tsn = 0; dp.stream = htons(sinfo->sinfo_stream); dp.ppid = sinfo->sinfo_ppid; /* Set the flags for an unordered send. */ if (sinfo->sinfo_flags & SCTP_UNORDERED) { flags |= SCTP_DATA_UNORDERED; dp.ssn = 0; } else dp.ssn = htons(ssn); chunk_len = sizeof(dp) + data_len; retval = sctp_make_data(asoc, flags, chunk_len); if (!retval) goto nodata; retval->subh.data_hdr = sctp_addto_chunk(retval, sizeof(dp), &dp); memcpy(&retval->sinfo, sinfo, sizeof(struct sctp_sndrcvinfo)); nodata: return retval; }
/* 3.3.11 Cookie Echo (COOKIE ECHO) (10): * * This chunk is used only during the initialization of an association. * It is sent by the initiator of an association to its peer to complete * the initialization process. This chunk MUST precede any DATA chunk * sent within the association, but MAY be bundled with one or more DATA * chunks in the same packet. * * 0 1 2 3 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Type = 10 |Chunk Flags | Length | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * / Cookie / * \ \ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * * Chunk Flags: 8 bit * * Set to zero on transmit and ignored on receipt. * * Length: 16 bits (unsigned integer) * * Set to the size of the chunk in bytes, including the 4 bytes of * the chunk header and the size of the Cookie. * * Cookie: variable size * * This field must contain the exact cookie received in the * State Cookie parameter from the previous INIT ACK. * * An implementation SHOULD make the cookie as small as possible * to insure interoperability. */ struct sctp_chunk *sctp_make_cookie_echo(const struct sctp_association *asoc, const struct sctp_chunk *chunk) { struct sctp_chunk *retval; void *cookie; int cookie_len; cookie = asoc->peer.cookie; cookie_len = asoc->peer.cookie_len; /* Build a cookie echo chunk. */ retval = sctp_make_control(asoc, SCTP_CID_COOKIE_ECHO, 0, cookie_len); if (!retval) goto nodata; retval->subh.cookie_hdr = sctp_addto_chunk(retval, cookie_len, cookie); /* RFC 2960 6.4 Multi-homed SCTP Endpoints * * An endpoint SHOULD transmit reply chunks (e.g., SACK, * HEARTBEAT ACK, * etc.) to the same destination transport * address from which it * received the DATA or control chunk * to which it is replying. * * [COOKIE ECHO back to where the INIT ACK came from.] */ if (chunk) retval->transport = chunk->transport; nodata: return retval; }
/* A helper to initialize an op error inside a * provided chunk, as most cause codes will be embedded inside an * abort chunk. */ void sctp_init_cause(struct sctp_chunk *chunk, __be16 cause_code, size_t paylen) { sctp_errhdr_t err; __u16 len; /* Cause code constants are now defined in network order. */ err.cause = cause_code; len = sizeof(sctp_errhdr_t) + paylen; err.length = htons(len); chunk->subh.err_hdr = sctp_addto_chunk(chunk, sizeof(sctp_errhdr_t), &err); }
/* Make an ECNE chunk. This is a congestion experienced report. */ struct sctp_chunk *sctp_make_ecne(const struct sctp_association *asoc, const __u32 lowest_tsn) { struct sctp_chunk *retval; sctp_ecnehdr_t ecne; ecne.lowest_tsn = htonl(lowest_tsn); retval = sctp_make_control(asoc, SCTP_CID_ECN_ECNE, 0, sizeof(sctp_ecnehdr_t)); if (!retval) goto nodata; retval->subh.ecne_hdr = sctp_addto_chunk(retval, sizeof(ecne), &ecne); nodata: return retval; }
/* Make a SHUTDOWN chunk. */ struct sctp_chunk *sctp_make_shutdown(const struct sctp_association *asoc, const struct sctp_chunk *chunk) { struct sctp_chunk *retval; sctp_shutdownhdr_t shut; __u32 ctsn; ctsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map); shut.cum_tsn_ack = htonl(ctsn); retval = sctp_make_control(asoc, SCTP_CID_SHUTDOWN, 0, sizeof(sctp_shutdownhdr_t)); if (!retval) goto nodata; retval->subh.shutdown_hdr = sctp_addto_chunk(retval, sizeof(shut), &shut); if (chunk) retval->transport = chunk->transport; nodata: return retval; }
/* * Respond to a normal INIT chunk. * We are the side that is being asked for an association. * * Section: 5.1 Normal Establishment of an Association, B * B) "Z" shall respond immediately with an INIT ACK chunk. The * destination IP address of the INIT ACK MUST be set to the source * IP address of the INIT to which this INIT ACK is responding. In * the response, besides filling in other parameters, "Z" must set the * Verification Tag field to Tag_A, and also provide its own * Verification Tag (Tag_Z) in the Initiate Tag field. * * Verification Tag: Must be 0. * * Inputs * (endpoint, asoc, chunk) * * Outputs * (asoc, reply_msg, msg_up, timers, counters) * * The return value is the disposition of the chunk. */ sctp_disposition_t sctp_sf_do_5_1B_init(struct net *net, const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { struct sctp_chunk *chunk = arg; struct sctp_chunk *repl; struct sctp_association *new_asoc; struct sctp_chunk *err_chunk; struct sctp_packet *packet; sctp_unrecognized_param_t *unk_param; int len; /* 6.10 Bundling * An endpoint MUST NOT bundle INIT, INIT ACK or * SHUTDOWN COMPLETE with any other chunks. * * IG Section 2.11.2 * Furthermore, we require that the receiver of an INIT chunk MUST * enforce these rules by silently discarding an arriving packet * with an INIT chunk that is bundled with other chunks. */ if (!chunk->singleton) return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); /* If the packet is an OOTB packet which is temporarily on the * control endpoint, respond with an ABORT. */ if (ep == sctp_sk(net->sctp.ctl_sock)->ep) { SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); } /* 3.1 A packet containing an INIT chunk MUST have a zero Verification * Tag. */ if (chunk->sctp_hdr->vtag != 0) return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); /* Make sure that the INIT chunk has a valid length. * Normally, this would cause an ABORT with a Protocol Violation * error, but since we don't have an association, we'll * just discard the packet. */ if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t))) return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); /* If the INIT is coming toward a closing socket, we'll send back * and ABORT. Essentially, this catches the race of INIT being * backloged to the socket at the same time as the user isses close(). * Since the socket and all its associations are going away, we * can treat this OOTB */ if (sctp_sstate(ep->base.sk, CLOSING)) return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); /* Verify the INIT chunk before processing it. */ err_chunk = NULL; if (!sctp_verify_init(net, asoc, chunk->chunk_hdr->type, (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, &err_chunk)) { /* This chunk contains fatal error. It is to be discarded. * Send an ABORT, with causes if there is any. */ if (err_chunk) { packet = sctp_abort_pkt_new(net, ep, asoc, arg, (__u8 *)(err_chunk->chunk_hdr) + sizeof(sctp_chunkhdr_t), ntohs(err_chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t)); 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 = (sctp_inithdr_t *)chunk->skb->data; /* Tag the variable length parameters. */ chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); if (!new_asoc) goto nomem; 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), (sctp_init_chunk_t *)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(sctp_chunkhdr_t); 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 = (sctp_unrecognized_param_t *) ((__u8 *)(err_chunk->chunk_hdr) + sizeof(sctp_chunkhdr_t)); /* 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)); /* * Note: After sending out INIT ACK with the State Cookie parameter, * "Z" MUST NOT allocate any resources, nor keep any states for the * new association. Otherwise, "Z" will be vulnerable to resource * attacks. */ sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); return SCTP_DISPOSITION_DELETE_TCB; nomem_init: sctp_association_free(new_asoc); nomem: if (err_chunk) sctp_chunk_free(err_chunk); return SCTP_DISPOSITION_NOMEM; }
/* Create a selective ackowledgement (SACK) for the given * association. This reports on which TSN's we've seen to date, * including duplicates and gaps. */ struct sctp_chunk *sctp_make_sack(const struct sctp_association *asoc) { struct sctp_chunk *retval; struct sctp_sackhdr sack; int len; __u32 ctsn; __u16 num_gabs, num_dup_tsns; struct sctp_association *aptr = (struct sctp_association *)asoc; struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map; struct sctp_gap_ack_block gabs[SCTP_MAX_GABS]; struct sctp_transport *trans; memset(gabs, 0, sizeof(gabs)); ctsn = sctp_tsnmap_get_ctsn(map); pr_debug("%s: sackCTSNAck sent:0x%x\n", __func__, ctsn); /* How much room is needed in the chunk? */ num_gabs = sctp_tsnmap_num_gabs(map, gabs); num_dup_tsns = sctp_tsnmap_num_dups(map); /* Initialize the SACK header. */ sack.cum_tsn_ack = htonl(ctsn); sack.a_rwnd = htonl(asoc->a_rwnd); sack.num_gap_ack_blocks = htons(num_gabs); sack.num_dup_tsns = htons(num_dup_tsns); len = sizeof(sack) + sizeof(struct sctp_gap_ack_block) * num_gabs + sizeof(__u32) * num_dup_tsns; /* Create the chunk. */ retval = sctp_make_control(asoc, SCTP_CID_SACK, 0, len); if (!retval) goto nodata; /* RFC 2960 6.4 Multi-homed SCTP Endpoints * * An endpoint SHOULD transmit reply chunks (e.g., SACK, * HEARTBEAT ACK, etc.) to the same destination transport * address from which it received the DATA or control chunk to * which it is replying. This rule should also be followed if * the endpoint is bundling DATA chunks together with the * reply chunk. * * However, when acknowledging multiple DATA chunks received * in packets from different source addresses in a single * SACK, the SACK chunk may be transmitted to one of the * destination transport addresses from which the DATA or * control chunks being acknowledged were received. * * [BUG: We do not implement the following paragraph. * Perhaps we should remember the last transport we used for a * SACK and avoid that (if possible) if we have seen any * duplicates. --piggy] * * When a receiver of a duplicate DATA chunk sends a SACK to a * multi- homed endpoint it MAY be beneficial to vary the * destination address and not use the source address of the * DATA chunk. The reason being that receiving a duplicate * from a multi-homed endpoint might indicate that the return * path (as specified in the source address of the DATA chunk) * for the SACK is broken. * * [Send to the address from which we last received a DATA chunk.] */ retval->transport = asoc->peer.last_data_from; retval->subh.sack_hdr = sctp_addto_chunk(retval, sizeof(sack), &sack); /* Add the gap ack block information. */ if (num_gabs) sctp_addto_chunk(retval, sizeof(__u32) * num_gabs, gabs); /* Add the duplicate TSN information. */ if (num_dup_tsns) { aptr->stats.idupchunks += num_dup_tsns; sctp_addto_chunk(retval, sizeof(__u32) * num_dup_tsns, sctp_tsnmap_get_dups(map)); } /* Once we have a sack generated, check to see what our sack * generation is, if its 0, reset the transports to 0, and reset * the association generation to 1 * * The idea is that zero is never used as a valid generation for the * association so no transport will match after a wrap event like this, * Until the next sack */ if (++aptr->peer.sack_generation == 0) { list_for_each_entry(trans, &asoc->peer.transport_addr_list, transports) trans->sack_generation = 0; aptr->peer.sack_generation = 1; } nodata: return retval; }
struct sctp_chunk *sctp_make_init_ack(const struct sctp_association *asoc, const struct sctp_chunk *chunk, gfp_t gfp, int unkparam_len) { sctp_inithdr_t initack; struct sctp_chunk *retval; union sctp_params addrs; struct sctp_sock *sp; int addrs_len; sctp_cookie_param_t *cookie; int cookie_len; size_t chunksize; sctp_adaptation_ind_param_t aiparam; sctp_supported_ext_param_t ext_param; int num_ext = 0; __u8 extensions[3]; sctp_paramhdr_t *auth_chunks = NULL, *auth_hmacs = NULL, *auth_random = NULL; retval = NULL; /* Note: there may be no addresses to embed. */ addrs = sctp_bind_addrs_to_raw(&asoc->base.bind_addr, &addrs_len, gfp); initack.init_tag = htonl(asoc->c.my_vtag); initack.a_rwnd = htonl(asoc->rwnd); initack.num_outbound_streams = htons(asoc->c.sinit_num_ostreams); initack.num_inbound_streams = htons(asoc->c.sinit_max_instreams); initack.initial_tsn = htonl(asoc->c.initial_tsn); /* FIXME: We really ought to build the cookie right * into the packet instead of allocating more fresh memory. */ cookie = sctp_pack_cookie(asoc->ep, asoc, chunk, &cookie_len, addrs.v, addrs_len); if (!cookie) goto nomem_cookie; /* Calculate the total size of allocation, include the reserved * space for reporting unknown parameters if it is specified. */ sp = sctp_sk(asoc->base.sk); chunksize = sizeof(initack) + addrs_len + cookie_len + unkparam_len; /* Tell peer that we'll do ECN only if peer advertised such cap. */ if (asoc->peer.ecn_capable) chunksize += sizeof(ecap_param); if (asoc->peer.prsctp_capable) chunksize += sizeof(prsctp_param); if (asoc->peer.asconf_capable) { extensions[num_ext] = SCTP_CID_ASCONF; extensions[num_ext+1] = SCTP_CID_ASCONF_ACK; num_ext += 2; } if (sp->adaptation_ind) chunksize += sizeof(aiparam); if (asoc->peer.auth_capable) { auth_random = (sctp_paramhdr_t *)asoc->c.auth_random; chunksize += ntohs(auth_random->length); auth_hmacs = (sctp_paramhdr_t *)asoc->c.auth_hmacs; if (auth_hmacs->length) chunksize += WORD_ROUND(ntohs(auth_hmacs->length)); else auth_hmacs = NULL; auth_chunks = (sctp_paramhdr_t *)asoc->c.auth_chunks; if (auth_chunks->length) chunksize += WORD_ROUND(ntohs(auth_chunks->length)); else auth_chunks = NULL; extensions[num_ext] = SCTP_CID_AUTH; num_ext += 1; } if (num_ext) chunksize += WORD_ROUND(sizeof(sctp_supported_ext_param_t) + num_ext); /* Now allocate and fill out the chunk. */ retval = sctp_make_control(asoc, SCTP_CID_INIT_ACK, 0, chunksize); if (!retval) goto nomem_chunk; /* RFC 2960 6.4 Multi-homed SCTP Endpoints * * An endpoint SHOULD transmit reply chunks (e.g., SACK, * HEARTBEAT ACK, * etc.) to the same destination transport * address from which it received the DATA or control chunk * to which it is replying. * * [INIT ACK back to where the INIT came from.] */ retval->transport = chunk->transport; retval->subh.init_hdr = sctp_addto_chunk(retval, sizeof(initack), &initack); retval->param_hdr.v = sctp_addto_chunk(retval, addrs_len, addrs.v); sctp_addto_chunk(retval, cookie_len, cookie); if (asoc->peer.ecn_capable) sctp_addto_chunk(retval, sizeof(ecap_param), &ecap_param); if (num_ext) { ext_param.param_hdr.type = SCTP_PARAM_SUPPORTED_EXT; ext_param.param_hdr.length = htons(sizeof(sctp_supported_ext_param_t) + num_ext); sctp_addto_chunk(retval, sizeof(sctp_supported_ext_param_t), &ext_param); sctp_addto_param(retval, num_ext, extensions); } if (asoc->peer.prsctp_capable) sctp_addto_chunk(retval, sizeof(prsctp_param), &prsctp_param); if (sp->adaptation_ind) { aiparam.param_hdr.type = SCTP_PARAM_ADAPTATION_LAYER_IND; aiparam.param_hdr.length = htons(sizeof(aiparam)); aiparam.adaptation_ind = htonl(sp->adaptation_ind); sctp_addto_chunk(retval, sizeof(aiparam), &aiparam); } if (asoc->peer.auth_capable) { sctp_addto_chunk(retval, ntohs(auth_random->length), auth_random); if (auth_hmacs) sctp_addto_chunk(retval, ntohs(auth_hmacs->length), auth_hmacs); if (auth_chunks) sctp_addto_chunk(retval, ntohs(auth_chunks->length), auth_chunks); } /* We need to remove the const qualifier at this point. */ retval->asoc = (struct sctp_association *) asoc; nomem_chunk: kfree(cookie); nomem_cookie: kfree(addrs.v); return retval; }
/* 3.3.2 Initiation (INIT) (1) * * This chunk is used to initiate a SCTP association between two * endpoints. The format of the INIT chunk is shown below: * * 0 1 2 3 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Type = 1 | Chunk Flags | Chunk Length | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Initiate Tag | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Advertised Receiver Window Credit (a_rwnd) | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Number of Outbound Streams | Number of Inbound Streams | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Initial TSN | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * \ \ * / Optional/Variable-Length Parameters / * \ \ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * * * The INIT chunk contains the following parameters. Unless otherwise * noted, each parameter MUST only be included once in the INIT chunk. * * Fixed Parameters Status * ---------------------------------------------- * Initiate Tag Mandatory * Advertised Receiver Window Credit Mandatory * Number of Outbound Streams Mandatory * Number of Inbound Streams Mandatory * Initial TSN Mandatory * * Variable Parameters Status Type Value * ------------------------------------------------------------- * IPv4 Address (Note 1) Optional 5 * IPv6 Address (Note 1) Optional 6 * Cookie Preservative Optional 9 * Reserved for ECN Capable (Note 2) Optional 32768 (0x8000) * Host Name Address (Note 3) Optional 11 * Supported Address Types (Note 4) Optional 12 */ struct sctp_chunk *sctp_make_init(const struct sctp_association *asoc, const struct sctp_bind_addr *bp, gfp_t gfp, int vparam_len) { struct net *net = sock_net(asoc->base.sk); struct sctp_endpoint *ep = asoc->ep; sctp_inithdr_t init; union sctp_params addrs; size_t chunksize; struct sctp_chunk *retval = NULL; int num_types, addrs_len = 0; struct sctp_sock *sp; sctp_supported_addrs_param_t sat; __be16 types[2]; sctp_adaptation_ind_param_t aiparam; sctp_supported_ext_param_t ext_param; int num_ext = 0; __u8 extensions[3]; sctp_paramhdr_t *auth_chunks = NULL, *auth_hmacs = NULL; /* RFC 2960 3.3.2 Initiation (INIT) (1) * * Note 1: The INIT chunks can contain multiple addresses that * can be IPv4 and/or IPv6 in any combination. */ retval = NULL; /* Convert the provided bind address list to raw format. */ addrs = sctp_bind_addrs_to_raw(bp, &addrs_len, gfp); init.init_tag = htonl(asoc->c.my_vtag); init.a_rwnd = htonl(asoc->rwnd); init.num_outbound_streams = htons(asoc->c.sinit_num_ostreams); init.num_inbound_streams = htons(asoc->c.sinit_max_instreams); init.initial_tsn = htonl(asoc->c.initial_tsn); /* How many address types are needed? */ sp = sctp_sk(asoc->base.sk); num_types = sp->pf->supported_addrs(sp, types); chunksize = sizeof(init) + addrs_len; chunksize += WORD_ROUND(SCTP_SAT_LEN(num_types)); chunksize += sizeof(ecap_param); if (net->sctp.prsctp_enable) chunksize += sizeof(prsctp_param); /* ADDIP: Section 4.2.7: * An implementation supporting this extension [ADDIP] MUST list * the ASCONF,the ASCONF-ACK, and the AUTH chunks in its INIT and * INIT-ACK parameters. */ if (net->sctp.addip_enable) { extensions[num_ext] = SCTP_CID_ASCONF; extensions[num_ext+1] = SCTP_CID_ASCONF_ACK; num_ext += 2; } if (sp->adaptation_ind) chunksize += sizeof(aiparam); chunksize += vparam_len; /* Account for AUTH related parameters */ if (ep->auth_enable) { /* Add random parameter length*/ chunksize += sizeof(asoc->c.auth_random); /* Add HMACS parameter length if any were defined */ auth_hmacs = (sctp_paramhdr_t *)asoc->c.auth_hmacs; if (auth_hmacs->length) chunksize += WORD_ROUND(ntohs(auth_hmacs->length)); else auth_hmacs = NULL; /* Add CHUNKS parameter length */ auth_chunks = (sctp_paramhdr_t *)asoc->c.auth_chunks; if (auth_chunks->length) chunksize += WORD_ROUND(ntohs(auth_chunks->length)); else auth_chunks = NULL; extensions[num_ext] = SCTP_CID_AUTH; num_ext += 1; } /* If we have any extensions to report, account for that */ if (num_ext) chunksize += WORD_ROUND(sizeof(sctp_supported_ext_param_t) + num_ext); /* RFC 2960 3.3.2 Initiation (INIT) (1) * * Note 3: An INIT chunk MUST NOT contain more than one Host * Name address parameter. Moreover, the sender of the INIT * MUST NOT combine any other address types with the Host Name * address in the INIT. The receiver of INIT MUST ignore any * other address types if the Host Name address parameter is * present in the received INIT chunk. * * PLEASE DO NOT FIXME [This version does not support Host Name.] */ retval = sctp_make_control(asoc, SCTP_CID_INIT, 0, chunksize); if (!retval) goto nodata; retval->subh.init_hdr = sctp_addto_chunk(retval, sizeof(init), &init); retval->param_hdr.v = sctp_addto_chunk(retval, addrs_len, addrs.v); /* RFC 2960 3.3.2 Initiation (INIT) (1) * * Note 4: This parameter, when present, specifies all the * address types the sending endpoint can support. The absence * of this parameter indicates that the sending endpoint can * support any address type. */ sat.param_hdr.type = SCTP_PARAM_SUPPORTED_ADDRESS_TYPES; sat.param_hdr.length = htons(SCTP_SAT_LEN(num_types)); sctp_addto_chunk(retval, sizeof(sat), &sat); sctp_addto_chunk(retval, num_types * sizeof(__u16), &types); sctp_addto_chunk(retval, sizeof(ecap_param), &ecap_param); /* Add the supported extensions parameter. Be nice and add this * fist before addiding the parameters for the extensions themselves */ if (num_ext) { ext_param.param_hdr.type = SCTP_PARAM_SUPPORTED_EXT; ext_param.param_hdr.length = htons(sizeof(sctp_supported_ext_param_t) + num_ext); sctp_addto_chunk(retval, sizeof(sctp_supported_ext_param_t), &ext_param); sctp_addto_param(retval, num_ext, extensions); } if (net->sctp.prsctp_enable) sctp_addto_chunk(retval, sizeof(prsctp_param), &prsctp_param); if (sp->adaptation_ind) { aiparam.param_hdr.type = SCTP_PARAM_ADAPTATION_LAYER_IND; aiparam.param_hdr.length = htons(sizeof(aiparam)); aiparam.adaptation_ind = htonl(sp->adaptation_ind); sctp_addto_chunk(retval, sizeof(aiparam), &aiparam); } /* Add SCTP-AUTH chunks to the parameter list */ if (ep->auth_enable) { sctp_addto_chunk(retval, sizeof(asoc->c.auth_random), asoc->c.auth_random); if (auth_hmacs) sctp_addto_chunk(retval, ntohs(auth_hmacs->length), auth_hmacs); if (auth_chunks) sctp_addto_chunk(retval, ntohs(auth_chunks->length), auth_chunks); } nodata: kfree(addrs.v); return retval; }