/* SCTP kernel reference Implementation * Copyright (c) 1999-2000 Cisco, Inc. * Copyright (c) 1999-2001 Motorola, Inc. * Copyright (c) 2001-2002 Intel Corp. * Copyright (c) 2001-2002 International Business Machines Corp. * * This file is part of the SCTP kernel reference Implementation * * This file includes part of the implementation of the add-IP extension, * based on <draft-ietf-tsvwg-addip-sctp-02.txt> June 29, 2001, * for the SCTP kernel reference Implementation. * * These functions work with the state functions in sctp_sm_statefuns.c * to implement the state operations. These functions implement the * steps which require modifying existing data structures. * * The SCTP reference implementation is free software; * you can redistribute it and/or modify it under the terms of * the GNU General Public License as published by * the Free Software Foundation; either version 2, or (at your option) * any later version. * * The SCTP reference implementation is distributed in the hope that it * will be useful, but WITHOUT ANY WARRANTY; without even the implied * ************************ * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. * See the GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with GNU CC; see the file COPYING. If not, write to * the Free Software Foundation, 59 Temple Place - Suite 330, * Boston, MA 02111-1307, USA. * * Please send any bug reports or fixes you make to the * email address(es): * lksctp developers <lksctp-developers@lists.sourceforge.net> * * Or submit a bug report through the following website: * http://www.sf.net/projects/lksctp * * Written or modified by: * La Monte H.P. Yarroll <piggy@acm.org> * Karl Knutson <karl@athena.chicago.il.us> * C. Robin <chris@hundredacre.ac.uk> * Jon Grimm <jgrimm@us.ibm.com> * Xingang Guo <xingang.guo@intel.com> * Dajiang Zhang <dajiang.zhang@nokia.com> * Sridhar Samudrala <sri@us.ibm.com> * Daisy Chang <daisyc@us.ibm.com> * Ardelle Fan <ardelle.fan@intel.com> * * Any bugs reported given to us we will try to fix... any fixes shared will * be incorporated into the next SCTP release. */ #include <linux/types.h> #include <linux/kernel.h> #include <linux/ip.h> #include <linux/ipv6.h> #include <linux/net.h> #include <linux/inet.h> #include <net/sock.h> #include <linux/skbuff.h> #include <linux/random.h> /* for get_random_bytes */ #include <net/sctp/sctp.h> #include <net/sctp/sm.h> /* 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. */ static const sctp_supported_addrs_param_t sat_param = { { SCTP_PARAM_SUPPORTED_ADDRESS_TYPES, __constant_htons(SCTP_SAT_LEN), } }; /* gcc 3.2 doesn't allow initialization of zero-length arrays. So the above * structure is split and the address types array is initialized using a * fixed length array. */ static const __u16 sat_addr_types[2] = { SCTP_PARAM_IPV4_ADDRESS, SCTP_V6(SCTP_PARAM_IPV6_ADDRESS,) }; /* RFC 2960 3.3.2 Initiation (INIT) (1) * * Note 2: The ECN capable field is reserved for future use of * Explicit Congestion Notification. */ static const sctp_ecn_capable_param_t ecap_param = { { SCTP_PARAM_ECN_CAPABLE, __constant_htons(sizeof(sctp_ecn_capable_param_t)), } }; /* A helper to initilize to initilize an op error inside a * provided chunk, as most cause codes will be embedded inside an * abort chunk. */ void sctp_init_cause(sctp_chunk_t *chunk, __u16 cause_code, const void *payload, size_t paylen) { sctp_errhdr_t err; int padlen; __u16 len; /* Cause code constants are now defined in network order. */ err.cause = cause_code; len = sizeof(sctp_errhdr_t) + paylen; padlen = len % 4; err.length = htons(len); len += padlen; sctp_addto_chunk(chunk, sizeof(sctp_errhdr_t), &err); chunk->subh.err_hdr = sctp_addto_chunk(chunk, paylen, payload); } /* 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 */ sctp_chunk_t *sctp_make_init(const sctp_association_t *asoc, const sctp_bind_addr_t *bp, int priority, int vparam_len) { sctp_inithdr_t init; union sctp_params addrs; size_t chunksize; sctp_chunk_t *retval = NULL; int addrs_len = 0; /* 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; addrs.v = NULL; /* Convert the provided bind address list to raw format */ addrs = sctp_bind_addrs_to_raw(bp, &addrs_len, priority); if (!addrs.v) goto nodata; 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); chunksize = sizeof(init) + addrs_len + SCTP_SAT_LEN; chunksize += sizeof(ecap_param); chunksize += vparam_len; /* 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_chunk(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); sctp_addto_chunk(retval, sizeof(sctp_paramhdr_t), &sat_param); sctp_addto_chunk(retval, sizeof(sat_addr_types), sat_addr_types); sctp_addto_chunk(retval, sizeof(ecap_param), &ecap_param); nodata: if (addrs.v) kfree(addrs.v); return retval; } sctp_chunk_t *sctp_make_init_ack(const sctp_association_t *asoc, const sctp_chunk_t *chunk, int priority, int unkparam_len) { sctp_inithdr_t initack; sctp_chunk_t *retval; union sctp_params addrs; int addrs_len; sctp_cookie_param_t *cookie; int cookie_len; size_t chunksize; retval = NULL; addrs = sctp_bind_addrs_to_raw(&asoc->base.bind_addr, &addrs_len, priority); if (!addrs.v) goto nomem_rawaddr; 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. */ 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); /* Now allocate and fill out the chunk. */ retval = sctp_make_chunk(asoc, SCTP_CID_INIT_ACK, 0, chunksize); if (!retval) goto nomem_chunk; /* Per the advice in RFC 2960 6.4, send this reply to * the source of the INIT packet. */ 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); /* We need to remove the const qualifier at this point. */ retval->asoc = (sctp_association_t *) asoc; /* 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.] */ if (chunk) retval->transport = chunk->transport; nomem_chunk: kfree(cookie); nomem_cookie: kfree(addrs.v); nomem_rawaddr: 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. */ sctp_chunk_t *sctp_make_cookie_echo(const sctp_association_t *asoc, const sctp_chunk_t *chunk) { sctp_chunk_t *retval; void *cookie; int cookie_len; cookie = asoc->peer.cookie; cookie_len = asoc->peer.cookie_len; /* Build a cookie echo chunk. */ retval = sctp_make_chunk(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; } /* 3.3.12 Cookie Acknowledgement (COOKIE ACK) (11): * * This chunk is used only during the initialization of an * association. It is used to acknowledge the receipt of a COOKIE * ECHO chunk. This chunk MUST precede any DATA or SACK chunk sent * within the association, but MAY be bundled with one or more DATA * chunks or SACK chunk in the same SCTP 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 = 11 |Chunk Flags | Length = 4 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * * Chunk Flags: 8 bits * * Set to zero on transmit and ignored on receipt. */ sctp_chunk_t *sctp_make_cookie_ack(const sctp_association_t *asoc, const sctp_chunk_t *chunk) { sctp_chunk_t *retval; retval = sctp_make_chunk(asoc, SCTP_CID_COOKIE_ACK, 0, 0); /* 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 ACK back to where the COOKIE ECHO came from.] */ if (retval && chunk) retval->transport = chunk->transport; 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. */ sctp_chunk_t *sctp_make_cwr(const sctp_association_t *asoc, const __u32 lowest_tsn, const sctp_chunk_t *chunk) { sctp_chunk_t *retval; sctp_cwrhdr_t cwr; cwr.lowest_tsn = htonl(lowest_tsn); retval = sctp_make_chunk(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 an ECNE chunk. This is a congestion experienced report. */ sctp_chunk_t *sctp_make_ecne(const sctp_association_t *asoc, const __u32 lowest_tsn) { sctp_chunk_t *retval; sctp_ecnehdr_t ecne; ecne.lowest_tsn = htonl(lowest_tsn); retval = sctp_make_chunk(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 DATA chunk for the given association from the provided * parameters. However, do not populate the data payload. */ sctp_chunk_t *sctp_make_datafrag_empty(sctp_association_t *asoc, const struct sctp_sndrcvinfo *sinfo, int data_len, __u8 flags, __u16 ssn) { sctp_chunk_t *retval; sctp_datahdr_t dp; int chunk_len; /* We assign the TSN as LATE as possible, not here when * creating the chunk. */ dp.tsn= 1000000; /* This marker is a debugging aid. */ dp.stream = htons(sinfo->sinfo_stream); dp.ppid = htonl(sinfo->sinfo_ppid); dp.ssn = htons(ssn); /* Set the flags for an unordered send. */ if (sinfo->sinfo_flags & MSG_UNORDERED) flags |= SCTP_DATA_UNORDERED; chunk_len = sizeof(dp) + data_len; retval = sctp_make_chunk(asoc, SCTP_CID_DATA, 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; } /* Make a DATA chunk for the given association. Populate the data * payload. */ sctp_chunk_t *sctp_make_datafrag(sctp_association_t *asoc, const struct sctp_sndrcvinfo *sinfo, int data_len, const __u8 *data, __u8 flags, __u16 ssn) { sctp_chunk_t *retval; retval = sctp_make_datafrag_empty(asoc, sinfo, data_len, flags, ssn); if (retval) sctp_addto_chunk(retval, data_len, data); return retval; } /* Make a DATA chunk for the given association to ride on stream id * 'stream', with a payload id of 'payload', and a body of 'data'. */ sctp_chunk_t *sctp_make_data(sctp_association_t *asoc, const struct sctp_sndrcvinfo *sinfo, int data_len, const __u8 *data) { sctp_chunk_t *retval = NULL; retval = sctp_make_data_empty(asoc, sinfo, data_len); if (retval) sctp_addto_chunk(retval, data_len, data); return retval; } /* Make a DATA chunk for the given association to ride on stream id * 'stream', with a payload id of 'payload', and a body big enough to * hold 'data_len' octets of data. We use this version when we need * to build the message AFTER allocating memory. */ sctp_chunk_t *sctp_make_data_empty(sctp_association_t *asoc, const struct sctp_sndrcvinfo *sinfo, int data_len) { __u8 flags = SCTP_DATA_NOT_FRAG; return sctp_make_datafrag_empty(asoc, sinfo, data_len, flags, 0); } /* Create a selective ackowledgement (SACK) for the given * association. This reports on which TSN's we've seen to date, * including duplicates and gaps. */ sctp_chunk_t *sctp_make_sack(const sctp_association_t *asoc) { sctp_chunk_t *retval; sctp_sackhdr_t sack; sctp_gap_ack_block_t gab; int length; __u32 ctsn; struct sctp_tsnmap_iter iter; __u16 num_gabs, num_dup_tsns; struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map; ctsn = sctp_tsnmap_get_ctsn(map); SCTP_DEBUG_PRINTK("sackCTSNAck sent is 0x%x.\n", ctsn); /* Count the number of Gap Ack Blocks. */ sctp_tsnmap_iter_init(map, &iter); for (num_gabs = 0; sctp_tsnmap_next_gap_ack(map, &iter, &gab.start, &gab.end); num_gabs++) { /* Do nothing. */ } num_dup_tsns = sctp_tsnmap_num_dups(map); /* Initialize the SACK header. */ sack.cum_tsn_ack = htonl(ctsn); sack.a_rwnd = htonl(asoc->rwnd); sack.num_gap_ack_blocks = htons(num_gabs); sack.num_dup_tsns = htons(num_dup_tsns); length = sizeof(sack) + sizeof(sctp_gap_ack_block_t) * num_gabs + sizeof(__u32) * num_dup_tsns; /* Create the chunk. */ retval = sctp_make_chunk(asoc, SCTP_CID_SACK, 0, length); 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); /* Put the Gap Ack Blocks into the chunk. */ sctp_tsnmap_iter_init(map, &iter); while(sctp_tsnmap_next_gap_ack(map, &iter, &gab.start, &gab.end)) { gab.start = htons(gab.start); gab.end = htons(gab.end); sctp_addto_chunk(retval, sizeof(sctp_gap_ack_block_t), &gab); } /* Register the duplicates. */ sctp_addto_chunk(retval, sizeof(__u32) * num_dup_tsns, sctp_tsnmap_get_dups(map)); nodata: return retval; } /* Make a SHUTDOWN chunk. */ sctp_chunk_t *sctp_make_shutdown(const sctp_association_t *asoc) { sctp_chunk_t *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_chunk(asoc, SCTP_CID_SHUTDOWN, 0, sizeof(sctp_shutdownhdr_t)); if (!retval) goto nodata; retval->subh.shutdown_hdr = sctp_addto_chunk(retval, sizeof(shut), &shut); nodata: return retval; } sctp_chunk_t *sctp_make_shutdown_ack(const sctp_association_t *asoc, const sctp_chunk_t *chunk) { sctp_chunk_t *retval; retval = sctp_make_chunk(asoc, SCTP_CID_SHUTDOWN_ACK, 0, 0); /* 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. * * [ACK back to where the SHUTDOWN came from.] */ if (retval && chunk) retval->transport = chunk->transport; return retval; } sctp_chunk_t *sctp_make_shutdown_complete(const sctp_association_t *asoc, const sctp_chunk_t *chunk) { sctp_chunk_t *retval; __u8 flags = 0; /* Maybe set the T-bit if we have no association. */ flags |= asoc ? 0 : SCTP_CHUNK_FLAG_T; retval = sctp_make_chunk(asoc, SCTP_CID_SHUTDOWN_COMPLETE, flags, 0); /* 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 SHUTDOWN COMPLETE back to where the SHUTDOWN ACK * came from.] */ if (retval && chunk) retval->transport = chunk->transport; return retval; } /* Create an ABORT. Note that we set the T bit if we have no * association. */ sctp_chunk_t *sctp_make_abort(const sctp_association_t *asoc, const sctp_chunk_t *chunk, const size_t hint) { sctp_chunk_t *retval; __u8 flags = 0; /* Maybe set the T-bit if we have no association. */ flags |= asoc ? 0 : SCTP_CHUNK_FLAG_T; retval = sctp_make_chunk(asoc, SCTP_CID_ABORT, flags, hint); /* 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 (retval && chunk) retval->transport = chunk->transport; return retval; } /* Helper to create ABORT with a NO_USER_DATA error. */ sctp_chunk_t *sctp_make_abort_no_data(const sctp_association_t *asoc, const sctp_chunk_t *chunk, __u32 tsn) { sctp_chunk_t *retval; __u32 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, (const void *)&payload, sizeof(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; } /* Helper to create ABORT with a SCTP_ERROR_USER_ABORT error. */ sctp_chunk_t *sctp_make_abort_user(const sctp_association_t *asoc, const sctp_chunk_t *chunk, const struct msghdr *msg) { sctp_chunk_t *retval; void *payload = NULL, *payoff; size_t paylen; struct iovec *iov = msg->msg_iov; int iovlen = msg->msg_iovlen; paylen = get_user_iov_size(iov, iovlen); retval = sctp_make_abort(asoc, chunk, sizeof(sctp_errhdr_t) + paylen); if (!retval) goto err_chunk; if (paylen) { /* Put the msg_iov together into payload. */ payload = kmalloc(paylen, GFP_ATOMIC); if (!payload) goto err_payload; payoff = payload; for (; iovlen > 0; --iovlen) { if (copy_from_user(payoff, iov->iov_base, iov->iov_len)) goto err_copy; payoff += iov->iov_len; iov++; } } sctp_init_cause(retval, SCTP_ERROR_USER_ABORT, payload, paylen); if (paylen) kfree(payload); return retval; err_copy: kfree(payload); err_payload: sctp_free_chunk(retval); retval = NULL; err_chunk: return retval; } /* Make a HEARTBEAT chunk. */ sctp_chunk_t *sctp_make_heartbeat(const sctp_association_t *asoc, const struct sctp_transport *transport, const void *payload, const size_t paylen) { sctp_chunk_t *retval = sctp_make_chunk(asoc, SCTP_CID_HEARTBEAT, 0, paylen); if (!retval) goto nodata; /* Cast away the 'const', as this is just telling the chunk * what transport it belongs to. */ retval->transport = (struct sctp_transport *) transport; retval->subh.hbs_hdr = sctp_addto_chunk(retval, paylen, payload); nodata: return retval; } sctp_chunk_t *sctp_make_heartbeat_ack(const sctp_association_t *asoc, const sctp_chunk_t *chunk, const void *payload, const size_t paylen) { sctp_chunk_t *retval = sctp_make_chunk(asoc, SCTP_CID_HEARTBEAT_ACK, 0, paylen); if (!retval) goto nodata; retval->subh.hbs_hdr = sctp_addto_chunk(retval, paylen, 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. * * [HBACK back to where the HEARTBEAT came from.] */ if (chunk) retval->transport = chunk->transport; nodata: return retval; } /* Create an Operation Error chunk with the specified space reserved. * This routine can be used for containing multiple causes in the chunk. */ sctp_chunk_t *sctp_make_op_error_space(const sctp_association_t *asoc, const sctp_chunk_t *chunk, size_t size) { sctp_chunk_t *retval; retval = sctp_make_chunk(asoc, SCTP_CID_ERROR, 0, sizeof(sctp_errhdr_t) + size); 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. * */ if (chunk) retval->transport = chunk->transport; nodata: return retval; } /* Create an Operation Error chunk. */ sctp_chunk_t *sctp_make_op_error(const sctp_association_t *asoc, const sctp_chunk_t *chunk, __u16 cause_code, const void *payload, size_t paylen) { sctp_chunk_t *retval = sctp_make_op_error_space(asoc, chunk, paylen); if (!retval) goto nodata; sctp_init_cause(retval, cause_code, payload, paylen); nodata: return retval; } /******************************************************************** * 2nd Level Abstractions ********************************************************************/ /* Turn an skb into a chunk. * FIXME: Eventually move the structure directly inside the skb->cb[]. */ sctp_chunk_t *sctp_chunkify(struct sk_buff *skb, const sctp_association_t *asoc, struct sock *sk) { sctp_chunk_t *retval = t_new(sctp_chunk_t, GFP_ATOMIC); if (!retval) goto nodata; memset(retval, 0, sizeof(sctp_chunk_t)); if (!sk) { SCTP_DEBUG_PRINTK("chunkifying skb %p w/o an sk\n", skb); } retval->skb = skb; retval->asoc = (sctp_association_t *) asoc; retval->num_times_sent = 0; retval->has_tsn = 0; retval->has_ssn = 0; retval->rtt_in_progress = 0; retval->sent_at = jiffies; retval->singleton = 1; retval->end_of_packet = 0; retval->ecn_ce_done = 0; retval->pdiscard = 0; /* sctpimpguide-05.txt Section 2.8.2 * M1) Each time a new DATA chunk is transmitted * set the 'TSN.Missing.Report' count for that TSN to 0. The * 'TSN.Missing.Report' count will be used to determine missing chunks * and when to fast retransmit. */ retval->tsn_missing_report = 0; retval->tsn_gap_acked = 0; retval->fast_retransmit = 0; /* Polish the bead hole. */ INIT_LIST_HEAD(&retval->transmitted_list); INIT_LIST_HEAD(&retval->frag_list); SCTP_DBG_OBJCNT_INC(chunk); nodata: return retval; } /* Set chunk->source and dest based on the IP header in chunk->skb. */ void sctp_init_addrs(sctp_chunk_t *chunk, union sctp_addr *src, union sctp_addr *dest) { memcpy(&chunk->source, src, sizeof(union sctp_addr)); memcpy(&chunk->dest, dest, sizeof(union sctp_addr)); } /* Extract the source address from a chunk. */ const union sctp_addr *sctp_source(const sctp_chunk_t *chunk) { /* If we have a known transport, use that. */ if (chunk->transport) { return &chunk->transport->ipaddr; } else { /* Otherwise, extract it from the IP header. */ return &chunk->source; } } /* Create a new chunk, setting the type and flags headers from the * arguments, reserving enough space for a 'paylen' byte payload. */ sctp_chunk_t *sctp_make_chunk(const sctp_association_t *asoc, __u8 type, __u8 flags, int paylen) { sctp_chunk_t *retval; sctp_chunkhdr_t *chunk_hdr; struct sk_buff *skb; struct sock *sk; skb = dev_alloc_skb(WORD_ROUND(sizeof(sctp_chunkhdr_t) + paylen)); if (!skb) goto nodata; /* Make room for the chunk header. */ chunk_hdr = (sctp_chunkhdr_t *)skb_put(skb, sizeof(sctp_chunkhdr_t)); skb_pull(skb, sizeof(sctp_chunkhdr_t)); chunk_hdr->type = type; chunk_hdr->flags = flags; chunk_hdr->length = htons(sizeof(sctp_chunkhdr_t)); /* Move the data pointer back up to the start of the chunk. */ skb_push(skb, sizeof(sctp_chunkhdr_t)); sk = asoc ? asoc->base.sk : NULL; retval = sctp_chunkify(skb, asoc, sk); if (!retval) { dev_kfree_skb(skb); goto nodata; } retval->chunk_hdr = chunk_hdr; retval->chunk_end = ((__u8 *)chunk_hdr) + sizeof(sctp_chunkhdr_t); /* Set the skb to the belonging sock for accounting. */ skb->sk = sk; return retval; nodata: return NULL; } /* Release the memory occupied by a chunk. */ void sctp_free_chunk(sctp_chunk_t *chunk) { /* Make sure that we are not on any list. */ skb_unlink((struct sk_buff *) chunk); list_del(&chunk->transmitted_list); /* Free the chunk skb data and the SCTP_chunk stub itself. */ dev_kfree_skb(chunk->skb); kfree(chunk); SCTP_DBG_OBJCNT_DEC(chunk); } /* Append bytes to the end of a chunk. Will panic if chunk is not big * enough. */ void *sctp_addto_chunk(sctp_chunk_t *chunk, int len, const void *data) { void *target; void *padding; int chunklen = ntohs(chunk->chunk_hdr->length); int padlen = chunklen % 4; padding = skb_put(chunk->skb, padlen); target = skb_put(chunk->skb, len); memset(padding, 0, padlen); memcpy(target, data, len); /* Adjust the chunk length field. */ chunk->chunk_hdr->length = htons(chunklen + padlen + len); chunk->chunk_end = chunk->skb->tail; return target; } /* Append bytes from user space to the end of a chunk. Will panic if * chunk is not big enough. * Returns a kernel err value. */ static int sctp_user_addto_chunk(sctp_chunk_t *chunk, int off, int len, struct iovec *data) { __u8 *target; int err = 0; /* Make room in chunk for data. */ target = skb_put(chunk->skb, len); /* Copy data (whole iovec) into chunk */ if ((err = memcpy_fromiovecend(target, data, off, len))) goto out; /* Adjust the chunk length field. */ chunk->chunk_hdr->length = htons(ntohs(chunk->chunk_hdr->length) + len); chunk->chunk_end = chunk->skb->tail; out: return err; } /* A data chunk can have a maximum payload of (2^16 - 20). Break * down any such message into smaller chunks. Opportunistically, fragment * the chunks down to the current MTU constraints. We may get refragmented * later if the PMTU changes, but it is _much better_ to fragment immediately * with a reasonable guess than always doing our fragmentation on the * soft-interrupt. */ int sctp_datachunks_from_user(sctp_association_t *asoc, const struct sctp_sndrcvinfo *sinfo, struct msghdr *msg, int msg_len, struct sk_buff_head *chunks) { int max, whole, i, offset, over, err; int len, first_len; sctp_chunk_t *chunk; __u8 frag; /* What is a reasonable fragmentation point right now? */ max = asoc->pmtu; if (max < SCTP_MIN_PMTU) max = SCTP_MIN_PMTU; max -= SCTP_IP_OVERHEAD; /* Make sure not beyond maximum chunk size. */ if (max > SCTP_MAX_CHUNK_LEN) max = SCTP_MAX_CHUNK_LEN; /* Subtract out the overhead of a data chunk header. */ max -= sizeof(struct sctp_data_chunk); whole = 0; first_len = max; /* Encourage Cookie-ECHO bundling. */ if (asoc->state < SCTP_STATE_ESTABLISHED) { whole = msg_len / (max - SCTP_ARBITRARY_COOKIE_ECHO_LEN); /* Account for the DATA to be bundled with the COOKIE-ECHO. */ if (whole) { first_len = max - SCTP_ARBITRARY_COOKIE_ECHO_LEN; msg_len -= first_len; whole = 1; } } /* How many full sized? How many bytes leftover? */ whole += msg_len / max; over = msg_len % max; offset = 0; if (whole && over) SCTP_INC_STATS_USER(SctpFragUsrMsgs); /* Create chunks for all the full sized DATA chunks. */ for (i=0, len=first_len; i < whole; i++) { frag = SCTP_DATA_MIDDLE_FRAG; if (0 == i) frag |= SCTP_DATA_FIRST_FRAG; if ((i == (whole - 1)) && !over) frag |= SCTP_DATA_LAST_FRAG; chunk = sctp_make_datafrag_empty(asoc, sinfo, len, frag, 0); if (!chunk) goto nomem; err = sctp_user_addto_chunk(chunk, offset, len, msg->msg_iov); if (err < 0) goto errout; offset += len; /* Put the chunk->skb back into the form expected by send. */ __skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr - (__u8 *)chunk->skb->data); __skb_queue_tail(chunks, (struct sk_buff *)chunk); /* The first chunk, the first chunk was likely short * to allow bundling, so reset to full size. */ if (0 == i) len = max; } /* .. now the leftover bytes. */ if (over) { if (!whole) frag = SCTP_DATA_NOT_FRAG; else frag = SCTP_DATA_LAST_FRAG; chunk = sctp_make_datafrag_empty(asoc, sinfo, over, frag, 0); if (!chunk) goto nomem; err = sctp_user_addto_chunk(chunk, offset, over, msg->msg_iov); /* Put the chunk->skb back into the form expected by send. */ __skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr - (__u8 *)chunk->skb->data); if (err < 0) goto errout; __skb_queue_tail(chunks, (struct sk_buff *)chunk); } err = 0; goto out; nomem: err = -ENOMEM; errout: while ((chunk = (sctp_chunk_t *)__skb_dequeue(chunks))) sctp_free_chunk(chunk); out: return err; } /* Helper function to assign a TSN if needed. This assumes that both * the data_hdr and association have already been assigned. */ void sctp_chunk_assign_ssn(sctp_chunk_t *chunk) { __u16 ssn; __u16 sid; if (chunk->has_ssn) return; /* This is the last possible instant to assign a SSN. */ if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) { ssn = 0; } else { sid = htons(chunk->subh.data_hdr->stream); if (chunk->chunk_hdr->flags & SCTP_DATA_LAST_FRAG) ssn = sctp_ssn_next(&chunk->asoc->ssnmap->out, sid); else ssn = sctp_ssn_peek(&chunk->asoc->ssnmap->out, sid); ssn = htons(ssn); } chunk->subh.data_hdr->ssn = ssn; chunk->has_ssn = 1; } /* Helper function to assign a TSN if needed. This assumes that both * the data_hdr and association have already been assigned. */ void sctp_chunk_assign_tsn(sctp_chunk_t *chunk) { if (!chunk->has_tsn) { /* This is the last possible instant to * assign a TSN. */ chunk->subh.data_hdr->tsn = htonl(__sctp_association_get_next_tsn(chunk->asoc)); chunk->has_tsn = 1; } } /* Create a CLOSED association to use with an incoming packet. */ sctp_association_t *sctp_make_temp_asoc(const sctp_endpoint_t *ep, sctp_chunk_t *chunk, int priority) { sctp_association_t *asoc; sctp_scope_t scope; /* Create the bare association. */ scope = sctp_scope(sctp_source(chunk)); asoc = sctp_association_new(ep, ep->base.sk, scope, priority); if (!asoc) goto nodata; /* Create an entry for the source address of the packet. */ switch (chunk->skb->nh.iph->version) { case 4: asoc->c.peer_addr.v4.sin_family = AF_INET; asoc->c.peer_addr.v4.sin_port = ntohs(chunk->sctp_hdr->source); asoc->c.peer_addr.v4.sin_addr.s_addr = chunk->skb->nh.iph->saddr; break; case 6: asoc->c.peer_addr.v6.sin6_family = AF_INET6; asoc->c.peer_addr.v6.sin6_port = ntohs(chunk->sctp_hdr->source); asoc->c.peer_addr.v6.sin6_flowinfo = 0; /* BUG BUG BUG */ asoc->c.peer_addr.v6.sin6_addr = chunk->skb->nh.ipv6h->saddr; asoc->c.peer_addr.v6.sin6_scope_id = 0; /* BUG BUG BUG */ break; default: /* Yikes! I never heard of this kind of address. */ goto fail; }; nodata: return asoc; fail: sctp_association_free(asoc); return NULL; } /* Build a cookie representing asoc. * This INCLUDES the param header needed to put the cookie in the INIT ACK. */ sctp_cookie_param_t *sctp_pack_cookie(const sctp_endpoint_t *ep, const sctp_association_t *asoc, const sctp_chunk_t *init_chunk, int *cookie_len, const __u8 *raw_addrs, int addrs_len) { sctp_cookie_param_t *retval; sctp_signed_cookie_t *cookie; int headersize, bodysize; headersize = sizeof(sctp_paramhdr_t) + SCTP_SECRET_SIZE; bodysize = sizeof(sctp_cookie_t) + ntohs(init_chunk->chunk_hdr->length) + addrs_len; /* Pad out the cookie to a multiple to make the signature * functions simpler to write. */ if (bodysize % SCTP_COOKIE_MULTIPLE) bodysize += SCTP_COOKIE_MULTIPLE - (bodysize % SCTP_COOKIE_MULTIPLE); *cookie_len = headersize + bodysize; retval = (sctp_cookie_param_t *) kmalloc(*cookie_len, GFP_ATOMIC); if (!retval) { *cookie_len = 0; goto nodata; } /* Clear this memory since we are sending this data structure * out on the network. */ memset(retval, 0x00, *cookie_len); cookie = (sctp_signed_cookie_t *) retval->body; /* Set up the parameter header. */ retval->p.type = SCTP_PARAM_STATE_COOKIE; retval->p.length = htons(*cookie_len); /* Copy the cookie part of the association itself. */ cookie->c = asoc->c; /* Save the raw address list length in the cookie. */ cookie->c.raw_addr_list_len = addrs_len; /* Set an expiration time for the cookie. */ do_gettimeofday(&cookie->c.expiration); tv_add(&asoc->cookie_life, &cookie->c.expiration); /* Copy the peer's init packet. */ memcpy(&cookie->c.peer_init[0], init_chunk->chunk_hdr, ntohs(init_chunk->chunk_hdr->length)); /* Copy the raw local address list of the association. */ memcpy((__u8 *)&cookie->c.peer_init[0] + ntohs(init_chunk->chunk_hdr->length), raw_addrs, addrs_len); /* Sign the message. */ sctp_hash_digest(ep->secret_key[ep->current_key], SCTP_SECRET_SIZE, (__u8 *) &cookie->c, bodysize, cookie->signature); nodata: return retval; } /* Unpack the cookie from COOKIE ECHO chunk, recreating the association. */ sctp_association_t *sctp_unpack_cookie(const sctp_endpoint_t *ep, const sctp_association_t *asoc, sctp_chunk_t *chunk, int priority, int *error, sctp_chunk_t **err_chk_p) { sctp_association_t *retval = NULL; sctp_signed_cookie_t *cookie; sctp_cookie_t *bear_cookie; int headersize, bodysize; int fixed_size; __u8 digest_buf[SCTP_SIGNATURE_SIZE]; int secret; sctp_scope_t scope; headersize = sizeof(sctp_chunkhdr_t) + SCTP_SECRET_SIZE; bodysize = ntohs(chunk->chunk_hdr->length) - headersize; fixed_size = headersize + sizeof(sctp_cookie_t); /* Verify that the chunk looks like it even has a cookie. * There must be enough room for our cookie and our peer's * INIT chunk. */ if (ntohs(chunk->chunk_hdr->length) < (fixed_size + sizeof(sctp_chunkhdr_t))) goto malformed; /* Verify that the cookie has been padded out. */ if (bodysize % SCTP_COOKIE_MULTIPLE) goto malformed; /* Process the cookie. */ cookie = chunk->subh.cookie_hdr; bear_cookie = &cookie->c; /* Check the signature. */ secret = ep->current_key; sctp_hash_digest(ep->secret_key[secret], SCTP_SECRET_SIZE, (__u8 *) bear_cookie, bodysize, digest_buf); if (memcmp(digest_buf, cookie->signature, SCTP_SIGNATURE_SIZE)) { /* Try the previous key. */ secret = ep->last_key; sctp_hash_digest(ep->secret_key[secret], SCTP_SECRET_SIZE, (__u8 *) bear_cookie, bodysize, digest_buf); if (memcmp(digest_buf, cookie->signature, SCTP_SIGNATURE_SIZE)) { /* Yikes! Still bad signature! */ *error = -SCTP_IERROR_BAD_SIG; goto fail; } } /* Check to see if the cookie is stale. If there is already * an association, there is no need to check cookie's expiration * for init collision case of lost COOKIE ACK. */ if (!asoc && tv_lt(bear_cookie->expiration, chunk->skb->stamp)) { __u16 len; /* * Section 3.3.10.3 Stale Cookie Error (3) * * Cause of error * --------------- * Stale Cookie Error: Indicates the receipt of a valid State * Cookie that has expired. */ len = ntohs(chunk->chunk_hdr->length); *err_chk_p = sctp_make_op_error_space(asoc, chunk, len); if (*err_chk_p) { suseconds_t usecs = (chunk->skb->stamp.tv_sec - bear_cookie->expiration.tv_sec) * 1000000L + chunk->skb->stamp.tv_usec - bear_cookie->expiration.tv_usec; usecs = htonl(usecs); sctp_init_cause(*err_chk_p, SCTP_ERROR_STALE_COOKIE, &usecs, sizeof(usecs)); *error = -SCTP_IERROR_STALE_COOKIE; } else *error = -SCTP_IERROR_NOMEM; goto fail; } /* Make a new base association. */ scope = sctp_scope(sctp_source(chunk)); retval = sctp_association_new(ep, ep->base.sk, scope, priority); if (!retval) { *error = -SCTP_IERROR_NOMEM; goto fail; } /* Set up our peer's port number. */ retval->peer.port = ntohs(chunk->sctp_hdr->source); /* Populate the association from the cookie. */ retval->c = *bear_cookie; if (sctp_assoc_set_bind_addr_from_cookie(retval, bear_cookie, GFP_ATOMIC) < 0) { *error = -SCTP_IERROR_NOMEM; goto fail; } retval->next_tsn = retval->c.initial_tsn; retval->ctsn_ack_point = retval->next_tsn - 1; /* The INIT stuff will be done by the side effects. */ return retval; fail: if (retval) sctp_association_free(retval); return NULL; malformed: /* Yikes! The packet is either corrupt or deliberately * malformed. */ *error = -SCTP_IERROR_MALFORMED; goto fail; } /******************************************************************** * 3rd Level Abstractions ********************************************************************/ /* * Report a missing mandatory parameter. */ struct __sctp_missing { __u32 num_missing; __u16 type; } __attribute__((packed));; static int sctp_process_missing_param(const sctp_association_t *asoc, sctp_param_t paramtype, sctp_chunk_t *chunk, sctp_chunk_t **err_chk_p) { struct __sctp_missing report; __u16 len; len = WORD_ROUND(sizeof(report)); /* Make an ERROR chunk, preparing enough room for * returning multiple unknown parameters. */ if (!*err_chk_p) *err_chk_p = sctp_make_op_error_space(asoc, chunk, len); if (*err_chk_p) { report.num_missing = htonl(1); report.type = paramtype; sctp_init_cause(*err_chk_p, SCTP_ERROR_INV_PARAM, &report, sizeof(report)); } /* Stop processing this chunk. */ return 0; } /* Report an Invalid Mandatory Parameter. */ static int sctp_process_inv_mandatory(const sctp_association_t *asoc, sctp_chunk_t *chunk, sctp_chunk_t **err_chk_p) { /* Invalid Mandatory Parameter Error has no payload. */ if (!*err_chk_p) *err_chk_p = sctp_make_op_error_space(asoc, chunk, 0); if (*err_chk_p) sctp_init_cause(*err_chk_p, SCTP_ERROR_INV_PARAM, NULL, 0); /* Stop processing this chunk. */ return 0; } /* Do not attempt to handle the HOST_NAME parm. However, do * send back an indicator to the peer. */ static int sctp_process_hn_param(const sctp_association_t *asoc, union sctp_params param, sctp_chunk_t *chunk, sctp_chunk_t **err_chk_p) { __u16 len = ntohs(param.p->length); /* Make an ERROR chunk. */ if (!*err_chk_p) *err_chk_p = sctp_make_op_error_space(asoc, chunk, len); if (*err_chk_p) sctp_init_cause(*err_chk_p, SCTP_ERROR_DNS_FAILED, param.v, len); /* Stop processing this chunk. */ return 0; } /* RFC 3.2.1 & the Implementers Guide 2.2. * * The Parameter Types are encoded such that the * highest-order two bits specify the action that must be * taken if the processing endpoint does not recognize the * Parameter Type. * * 00 - Stop processing this SCTP chunk and discard it, * do not process any further chunks within it. * * 01 - Stop processing this SCTP chunk and discard it, * do not process any further chunks within it, and report * the unrecognized parameter in an 'Unrecognized * Parameter Type' (in either an ERROR or in the INIT ACK). * * 10 - Skip this parameter and continue processing. * * 11 - Skip this parameter and continue processing but * report the unrecognized parameter in an * 'Unrecognized Parameter Type' (in either an ERROR or in * the INIT ACK). * * Return value: * 0 - discard the chunk * 1 - continue with the chunk */ static int sctp_process_unk_param(const sctp_association_t *asoc, union sctp_params param, sctp_chunk_t *chunk, sctp_chunk_t **err_chk_p) { int retval = 1; switch (param.p->type & SCTP_PARAM_ACTION_MASK) { case SCTP_PARAM_ACTION_DISCARD: retval = 0; break; case SCTP_PARAM_ACTION_DISCARD_ERR: retval = 0; /* Make an ERROR chunk, preparing enough room for * returning multiple unknown parameters. */ if (NULL == *err_chk_p) *err_chk_p = sctp_make_op_error_space(asoc, chunk, ntohs(chunk->chunk_hdr->length)); if (*err_chk_p) sctp_init_cause(*err_chk_p, SCTP_ERROR_UNKNOWN_PARAM, param.v, WORD_ROUND(ntohs(param.p->length))); break; case SCTP_PARAM_ACTION_SKIP: break; case SCTP_PARAM_ACTION_SKIP_ERR: /* Make an ERROR chunk, preparing enough room for * returning multiple unknown parameters. */ if (NULL == *err_chk_p) *err_chk_p = sctp_make_op_error_space(asoc, chunk, ntohs(chunk->chunk_hdr->length)); if (*err_chk_p) { sctp_init_cause(*err_chk_p, SCTP_ERROR_UNKNOWN_PARAM, param.v, WORD_ROUND(ntohs(param.p->length))); } else { /* If there is no memory for generating the ERROR * report as specified, an ABORT will be triggered * to the peer and the association won't be * established. */ retval = 0; } break; default: break; } return retval; } /* Find unrecognized parameters in the chunk. * Return values: * 0 - discard the chunk * 1 - continue with the chunk */ static int sctp_verify_param(const sctp_association_t *asoc, union sctp_params param, sctp_cid_t cid, sctp_chunk_t *chunk, sctp_chunk_t **err_chunk) { int retval = 1; /* FIXME - This routine is not looking at each parameter per the * chunk type, i.e., unrecognized parameters should be further * identified based on the chunk id. */ switch (param.p->type) { case SCTP_PARAM_IPV4_ADDRESS: case SCTP_PARAM_IPV6_ADDRESS: case SCTP_PARAM_COOKIE_PRESERVATIVE: case SCTP_PARAM_SUPPORTED_ADDRESS_TYPES: case SCTP_PARAM_STATE_COOKIE: case SCTP_PARAM_HEARTBEAT_INFO: case SCTP_PARAM_UNRECOGNIZED_PARAMETERS: case SCTP_PARAM_ECN_CAPABLE: break; case SCTP_PARAM_HOST_NAME_ADDRESS: /* Tell the peer, we won't support this param. */ return sctp_process_hn_param(asoc, param, chunk, err_chunk); default: SCTP_DEBUG_PRINTK("Unrecognized param: %d for chunk %d.\n", ntohs(param.p->type), cid); return sctp_process_unk_param(asoc, param, chunk, err_chunk); break; } return retval; } /* Verify the INIT packet before we process it. */ int sctp_verify_init(const sctp_association_t *asoc, sctp_cid_t cid, sctp_init_chunk_t *peer_init, sctp_chunk_t *chunk, sctp_chunk_t **err_chk_p) { union sctp_params param; int has_cookie = 0; /* Verify stream values are non-zero. */ if ((0 == peer_init->init_hdr.num_outbound_streams) || (0 == peer_init->init_hdr.num_inbound_streams)) { sctp_process_inv_mandatory(asoc, chunk, err_chk_p); return 0; } /* Check for missing mandatory parameters. */ sctp_walk_params(param, peer_init, init_hdr.params) { if (SCTP_PARAM_STATE_COOKIE == param.p->type) has_cookie = 1; } /* for (loop through all parameters) */ /* The only missing mandatory param possible today is * the state cookie for an INIT-ACK chunk. */ if ((SCTP_CID_INIT_ACK == cid) && !has_cookie) { sctp_process_missing_param(asoc, SCTP_PARAM_STATE_COOKIE, chunk, err_chk_p); return 0; } /* Find unrecognized parameters. */ sctp_walk_params(param, peer_init, init_hdr.params) { if (!sctp_verify_param(asoc, param, cid, chunk, err_chk_p)) return 0; } /* for (loop through all parameters) */ return 1; } /* Unpack the parameters in an INIT packet into an association. * Returns 0 on failure, else success. * FIXME: This is an association method. */ int sctp_process_init(sctp_association_t *asoc, sctp_cid_t cid, const union sctp_addr *peer_addr, sctp_init_chunk_t *peer_init, int priority) { union sctp_params param; struct sctp_transport *transport; struct list_head *pos, *temp; char *cookie; /* We must include the address that the INIT packet came from. * This is the only address that matters for an INIT packet. * When processing a COOKIE ECHO, we retrieve the from address * of the INIT from the cookie. */ /* This implementation defaults to making the first transport * added as the primary transport. The source address seems to * be a a better choice than any of the embedded addresses. */ if (peer_addr) if(!sctp_assoc_add_peer(asoc, peer_addr, priority)) goto nomem; /* Process the initialization parameters. */ sctp_walk_params(param, peer_init, init_hdr.params) { if (!sctp_process_param(asoc, param, peer_addr, priority)) goto clean_up; } /* The fixed INIT headers are always in network byte * order. */ asoc->peer.i.init_tag = ntohl(peer_init->init_hdr.init_tag); asoc->peer.i.a_rwnd = ntohl(peer_init->init_hdr.a_rwnd); asoc->peer.i.num_outbound_streams = ntohs(peer_init->init_hdr.num_outbound_streams); asoc->peer.i.num_inbound_streams = ntohs(peer_init->init_hdr.num_inbound_streams); asoc->peer.i.initial_tsn = ntohl(peer_init->init_hdr.initial_tsn); /* Apply the upper bounds for output streams based on peer's * number of inbound streams. */ if (asoc->c.sinit_num_ostreams > ntohs(peer_init->init_hdr.num_inbound_streams)) { asoc->c.sinit_num_ostreams = ntohs(peer_init->init_hdr.num_inbound_streams); } if (asoc->c.sinit_max_instreams > ntohs(peer_init->init_hdr.num_outbound_streams)) { asoc->c.sinit_max_instreams = ntohs(peer_init->init_hdr.num_outbound_streams); } /* Copy Initiation tag from INIT to VT_peer in cookie. */ asoc->c.peer_vtag = asoc->peer.i.init_tag; /* Peer Rwnd : Current calculated value of the peer's rwnd. */ asoc->peer.rwnd = asoc->peer.i.a_rwnd; /* Copy cookie in case we need to resend COOKIE-ECHO. */ cookie = asoc->peer.cookie; if (cookie) { asoc->peer.cookie = kmalloc(asoc->peer.cookie_len, priority); if (!asoc->peer.cookie) goto clean_up; memcpy(asoc->peer.cookie, cookie, asoc->peer.cookie_len); } /* RFC 2960 7.2.1 The initial value of ssthresh MAY be arbitrarily * high (for example, implementations MAY use the size of the receiver * advertised window). */ list_for_each(pos, &asoc->peer.transport_addr_list) { transport = list_entry(pos, struct sctp_transport, transports); transport->ssthresh = asoc->peer.i.a_rwnd; } /* Set up the TSN tracking pieces. */ sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_SIZE, asoc->peer.i.initial_tsn); /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number * * The stream sequence number in all the streams shall start * from 0 when the association is established. Also, when the * stream sequence number reaches the value 65535 the next * stream sequence number shall be set to 0. */ /* Allocate storage for the negotiated streams. */ asoc->ssnmap = sctp_ssnmap_new(asoc->peer.i.num_outbound_streams, asoc->c.sinit_num_ostreams, priority); if (!asoc->ssnmap) goto nomem_ssnmap; /* ADDIP Section 4.1 ASCONF Chunk Procedures * * When an endpoint has an ASCONF signaled change to be sent to the * remote endpoint it should do the following: * ... * A2) A serial number should be assigned to the Chunk. The serial * number should be a monotonically increasing number. All serial * numbers are defined to be initialized at the start of the * association to the same value as the Initial TSN. */ asoc->peer.addip_serial = asoc->peer.i.initial_tsn - 1; return 1; nomem_ssnmap: clean_up: /* Release the transport structures. */ list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) { transport = list_entry(pos, struct sctp_transport, transports); list_del(pos); sctp_transport_free(transport); } nomem: return 0; } /* Update asoc with the option described in param. * * RFC2960 3.3.2.1 Optional/Variable Length Parameters in INIT * * asoc is the association to update. * param is the variable length parameter to use for update. * cid tells us if this is an INIT, INIT ACK or COOKIE ECHO. * If the current packet is an INIT we want to minimize the amount of * work we do. In particular, we should not build transport * structures for the addresses. */ int sctp_process_param(sctp_association_t *asoc, union sctp_params param, const union sctp_addr *peer_addr, int priority) { union sctp_addr addr; int i; __u16 sat; int retval = 1; sctp_scope_t scope; time_t stale; /* We maintain all INIT parameters in network byte order all the * time. This allows us to not worry about whether the parameters * came from a fresh INIT, and INIT ACK, or were stored in a cookie. */ switch (param.p->type) { case SCTP_PARAM_IPV6_ADDRESS: if( PF_INET6 != asoc->base.sk->family) break; /* Fall through. */ case SCTP_PARAM_IPV4_ADDRESS: sctp_param2sockaddr(&addr, param.addr, asoc->peer.port); scope = sctp_scope(peer_addr); if (sctp_in_scope(&addr, scope)) if (!sctp_assoc_add_peer(asoc, &addr, priority)) return 0; break; case SCTP_PARAM_COOKIE_PRESERVATIVE: if (!sctp_proto.cookie_preserve_enable) break; stale = ntohl(param.life->lifespan_increment); /* Suggested Cookie Life span increment's unit is msec, * (1/1000sec). */ asoc->cookie_life.tv_sec += stale / 1000; asoc->cookie_life.tv_usec += (stale % 1000) * 1000; break; case SCTP_PARAM_HOST_NAME_ADDRESS: SCTP_DEBUG_PRINTK("unimplemented SCTP_HOST_NAME_ADDRESS\n"); break; case SCTP_PARAM_SUPPORTED_ADDRESS_TYPES: /* Turn off the default values first so we'll know which * ones are really set by the peer. */ asoc->peer.ipv4_address = 0; asoc->peer.ipv6_address = 0; /* Cycle through address types; avoid divide by 0. */ sat = ntohs(param.p->length) - sizeof(sctp_paramhdr_t); if (sat) sat /= sizeof(__u16); for (i = 0; i < sat; ++i) { switch (param.sat->types[i]) { case SCTP_PARAM_IPV4_ADDRESS: asoc->peer.ipv4_address = 1; break; case SCTP_PARAM_IPV6_ADDRESS: asoc->peer.ipv6_address = 1; break; case SCTP_PARAM_HOST_NAME_ADDRESS: asoc->peer.hostname_address = 1; break; default: /* Just ignore anything else. */ break; }; } break; case SCTP_PARAM_STATE_COOKIE: asoc->peer.cookie_len = ntohs(param.p->length) - sizeof(sctp_paramhdr_t); asoc->peer.cookie = param.cookie->body; break; case SCTP_PARAM_HEARTBEAT_INFO: /* Would be odd to receive, but it causes no problems. */ break; case SCTP_PARAM_UNRECOGNIZED_PARAMETERS: /* Rejected during verify stage. */ break; case SCTP_PARAM_ECN_CAPABLE: asoc->peer.ecn_capable = 1; break; default: /* Any unrecognized parameters should have been caught * and handled by sctp_verify_param() which should be * called prior to this routine. Simply log the error * here. */ SCTP_DEBUG_PRINTK("Ignoring param: %d for association %p.\n", ntohs(param.p->type), asoc); break; }; return retval; } /* Select a new verification tag. */ __u32 sctp_generate_tag(const sctp_endpoint_t *ep) { /* I believe that this random number generator complies with RFC1750. * A tag of 0 is reserved for special cases (e.g. INIT). */ __u32 x; do { get_random_bytes(&x, sizeof(__u32)); } while (x == 0); return x; } /* Select an initial TSN to send during startup. */ __u32 sctp_generate_tsn(const sctp_endpoint_t *ep) { __u32 retval; get_random_bytes(&retval, sizeof(__u32)); return retval; } /******************************************************************** * 4th Level Abstractions ********************************************************************/ /* Convert from an SCTP IP parameter to a union sctp_addr. */ void sctp_param2sockaddr(union sctp_addr *addr, sctp_addr_param_t *param, __u16 port) { switch(param->v4.param_hdr.type) { case SCTP_PARAM_IPV4_ADDRESS: addr->v4.sin_family = AF_INET; addr->v4.sin_port = port; addr->v4.sin_addr.s_addr = param->v4.addr.s_addr; break; case SCTP_PARAM_IPV6_ADDRESS: addr->v6.sin6_family = AF_INET6; addr->v6.sin6_port = port; addr->v6.sin6_flowinfo = 0; /* BUG */ addr->v6.sin6_addr = param->v6.addr; addr->v6.sin6_scope_id = 0; /* BUG */ break; default: SCTP_DEBUG_PRINTK("Illegal address type %d\n", ntohs(param->v4.param_hdr.type)); break; }; } /* Convert an IP address in an SCTP param into a sockaddr_in. */ /* Returns true if a valid conversion was possible. */ int sctp_addr2sockaddr(union sctp_params p, union sctp_addr *sa) { switch (p.p->type) { case SCTP_PARAM_IPV4_ADDRESS: sa->v4.sin_addr = *((struct in_addr *)&p.v4->addr); sa->v4.sin_family = AF_INET; break; case SCTP_PARAM_IPV6_ADDRESS: *((struct in6_addr *)&sa->v4.sin_addr) = p.v6->addr; sa->v4.sin_family = AF_INET6; break; default: return 0; }; return 1; } /* Convert a sockaddr_in to an IP address in an SCTP param. * Returns len if a valid conversion was possible. */ int sockaddr2sctp_addr(const union sctp_addr *sa, sctp_addr_param_t *p) { int len = 0; switch (sa->v4.sin_family) { case AF_INET: p->v4.param_hdr.type = SCTP_PARAM_IPV4_ADDRESS; p->v4.param_hdr.length = ntohs(sizeof(sctp_ipv4addr_param_t)); len = sizeof(sctp_ipv4addr_param_t); p->v4.addr.s_addr = sa->v4.sin_addr.s_addr; break; case AF_INET6: p->v6.param_hdr.type = SCTP_PARAM_IPV6_ADDRESS; p->v6.param_hdr.length = ntohs(sizeof(sctp_ipv6addr_param_t)); len = sizeof(sctp_ipv6addr_param_t); p->v6.addr = *(&sa->v6.sin6_addr); break; default: printk(KERN_WARNING "sockaddr2sctp_addr: Illegal family %d.\n", sa->v4.sin_family); return 0; }; return len; }