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Diffstat (limited to 'net/sctp/sm_make_chunk.c')
| -rw-r--r-- | net/sctp/sm_make_chunk.c | 2766 |
1 files changed, 2766 insertions, 0 deletions
diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c new file mode 100644 index 00000000000..1db12cc18cf --- /dev/null +++ b/net/sctp/sm_make_chunk.c @@ -0,0 +1,2766 @@ +/* SCTP kernel reference Implementation + * (C) Copyright IBM Corp. 2001, 2004 + * Copyright (c) 1999-2000 Cisco, Inc. + * Copyright (c) 1999-2001 Motorola, Inc. + * Copyright (c) 2001-2002 Intel Corp. + * + * This file is part of 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> + * Kevin Gao <kevin.gao@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 <asm/scatterlist.h> +#include <linux/crypto.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> + +extern kmem_cache_t *sctp_chunk_cachep; + +SCTP_STATIC +struct sctp_chunk *sctp_make_chunk(const struct sctp_association *asoc, + __u8 type, __u8 flags, int paylen); +static sctp_cookie_param_t *sctp_pack_cookie(const struct sctp_endpoint *ep, + const struct sctp_association *asoc, + const struct sctp_chunk *init_chunk, + int *cookie_len, + const __u8 *raw_addrs, int addrs_len); +static int sctp_process_param(struct sctp_association *asoc, + union sctp_params param, + const union sctp_addr *peer_addr, + int gfp); + +/* What was the inbound interface for this chunk? */ +int sctp_chunk_iif(const struct sctp_chunk *chunk) +{ + struct sctp_af *af; + int iif = 0; + + af = sctp_get_af_specific(ipver2af(chunk->skb->nh.iph->version)); + if (af) + iif = af->skb_iif(chunk->skb); + + return iif; +} + +/* 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 struct sctp_paramhdr ecap_param = { + SCTP_PARAM_ECN_CAPABLE, + __constant_htons(sizeof(struct sctp_paramhdr)), +}; +static const struct sctp_paramhdr prsctp_param = { + SCTP_PARAM_FWD_TSN_SUPPORT, + __constant_htons(sizeof(struct sctp_paramhdr)), +}; + +/* A helper to initialize 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, __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 + */ +struct sctp_chunk *sctp_make_init(const struct sctp_association *asoc, + const struct sctp_bind_addr *bp, + int gfp, int vparam_len) +{ + 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; + __u16 types[2]; + sctp_adaption_ind_param_t aiparam; + + /* 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 + SCTP_SAT_LEN(num_types); + chunksize += sizeof(ecap_param); + if (sctp_prsctp_enable) + chunksize += sizeof(prsctp_param); + chunksize += sizeof(aiparam); + 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); + + /* 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); + if (sctp_prsctp_enable) + sctp_addto_chunk(retval, sizeof(prsctp_param), &prsctp_param); + aiparam.param_hdr.type = SCTP_PARAM_ADAPTION_LAYER_IND; + aiparam.param_hdr.length = htons(sizeof(aiparam)); + aiparam.adaption_ind = htonl(sp->adaption_ind); + sctp_addto_chunk(retval, sizeof(aiparam), &aiparam); +nodata: + if (addrs.v) + kfree(addrs.v); + return retval; +} + +struct sctp_chunk *sctp_make_init_ack(const struct sctp_association *asoc, + const struct sctp_chunk *chunk, + int gfp, int unkparam_len) +{ + sctp_inithdr_t initack; + struct sctp_chunk *retval; + union sctp_params addrs; + int addrs_len; + sctp_cookie_param_t *cookie; + int cookie_len; + size_t chunksize; + sctp_adaption_ind_param_t aiparam; + + 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. + */ + 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); + + /* Tell peer that we'll do PR-SCTP only if peer advertised. */ + if (asoc->peer.prsctp_capable) + chunksize += sizeof(prsctp_param); + + chunksize += sizeof(aiparam); + + /* 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); + if (asoc->peer.prsctp_capable) + sctp_addto_chunk(retval, sizeof(prsctp_param), &prsctp_param); + + aiparam.param_hdr.type = SCTP_PARAM_ADAPTION_LAYER_IND; + aiparam.param_hdr.length = htons(sizeof(aiparam)); + aiparam.adaption_ind = htonl(sctp_sk(asoc->base.sk)->adaption_ind); + sctp_addto_chunk(retval, sizeof(aiparam), &aiparam); + + /* We need to remove the const qualifier at this point. */ + retval->asoc = (struct sctp_association *) 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: + if (addrs.v) + kfree(addrs.v); + 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_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. + */ +struct sctp_chunk *sctp_make_cookie_ack(const struct sctp_association *asoc, + const struct sctp_chunk *chunk) +{ + struct sctp_chunk *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. + */ +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_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. */ +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_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. + */ +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 & MSG_UNORDERED) { + flags |= SCTP_DATA_UNORDERED; + dp.ssn = 0; + } else + dp.ssn = htons(ssn); + + 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; +} + +/* 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_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map; + + ctsn = sctp_tsnmap_get_ctsn(map); + SCTP_DEBUG_PRINTK("sackCTSNAck sent: 0x%x.\n", ctsn); + + /* How much room is needed in the chunk? */ + num_gabs = sctp_tsnmap_num_gabs(map); + 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_chunk(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, + sctp_tsnmap_get_gabs(map)); + + /* Add the duplicate TSN information. */ + if (num_dup_tsns) + sctp_addto_chunk(retval, sizeof(__u32) * num_dup_tsns, + sctp_tsnmap_get_dups(map)); + +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_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); + + if (chunk) + retval->transport = chunk->transport; +nodata: + return retval; +} + +struct sctp_chunk *sctp_make_shutdown_ack(const struct sctp_association *asoc, + const struct sctp_chunk *chunk) +{ + struct sctp_chunk *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; +} + +struct sctp_chunk *sctp_make_shutdown_complete( + const struct sctp_association *asoc, + const struct sctp_chunk *chunk) +{ + struct sctp_chunk *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. + */ +struct sctp_chunk *sctp_make_abort(const struct sctp_association *asoc, + const struct sctp_chunk *chunk, + const size_t hint) +{ + struct sctp_chunk *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. */ +struct sctp_chunk *sctp_make_abort_no_data( + const struct sctp_association *asoc, + const struct sctp_chunk *chunk, __u32 tsn) +{ + struct sctp_chunk *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. */ +struct sctp_chunk *sctp_make_abort_user(const struct sctp_association *asoc, + const struct sctp_chunk *chunk, + const struct msghdr *msg) +{ + struct sctp_chunk *retval; + void *payload = NULL, *payoff; + size_t paylen = 0; + struct iovec *iov = NULL; + int iovlen = 0; + + if (msg) { + iov = msg->msg_iov; + 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_chunk_free(retval); + retval = NULL; +err_chunk: + return retval; +} + +/* Make an ABORT chunk with a PROTOCOL VIOLATION cause code. */ +struct sctp_chunk *sctp_make_abort_violation( + const struct sctp_association *asoc, + const struct sctp_chunk *chunk, + const __u8 *payload, + const size_t paylen) +{ + struct sctp_chunk *retval; + struct sctp_paramhdr phdr; + + retval = sctp_make_abort(asoc, chunk, sizeof(sctp_errhdr_t) + paylen + + sizeof(sctp_chunkhdr_t)); + if (!retval) + goto end; + + sctp_init_cause(retval, SCTP_ERROR_PROTO_VIOLATION, payload, paylen); + + phdr.type = htons(chunk->chunk_hdr->type); + phdr.length = chunk->chunk_hdr->length; + sctp_addto_chunk(retval, sizeof(sctp_paramhdr_t), &phdr); + +end: + return retval; +} + +/* Make a HEARTBEAT chunk. */ +struct sctp_chunk *sctp_make_heartbeat(const struct sctp_association *asoc, + const struct sctp_transport *transport, + const void *payload, const size_t paylen) +{ + struct sctp_chunk *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; +} + +struct sctp_chunk *sctp_make_heartbeat_ack(const struct sctp_association *asoc, + const struct sctp_chunk *chunk, + const void *payload, const size_t paylen) +{ + struct sctp_chunk *retval; + + 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. + */ +static struct sctp_chunk *sctp_make_op_error_space( + const struct sctp_association *asoc, + const struct sctp_chunk *chunk, + size_t size) +{ + struct sctp_chunk *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. */ +struct sctp_chunk *sctp_make_op_error(const struct sctp_association *asoc, + const struct sctp_chunk *chunk, + __u16 cause_code, const void *payload, + size_t paylen) +{ + struct sctp_chunk *retval; + + 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[]. + */ +struct sctp_chunk *sctp_chunkify(struct sk_buff *skb, + const struct sctp_association *asoc, + struct sock *sk) +{ + struct sctp_chunk *retval; + + retval = kmem_cache_alloc(sctp_chunk_cachep, SLAB_ATOMIC); + + if (!retval) + goto nodata; + memset(retval, 0, sizeof(struct sctp_chunk)); + + if (!sk) { + SCTP_DEBUG_PRINTK("chunkifying skb %p w/o an sk\n", skb); + } + + retval->skb = skb; + retval->asoc = (struct sctp_association *)asoc; + retval->resent = 0; + retval->has_tsn = 0; + retval->has_ssn = 0; + retval->rtt_in_progress = 0; + retval->sent_at = 0; + 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; + + /* If this is a fragmented message, track all fragments + * of the message (for SEND_FAILED). + */ + retval->msg = NULL; + + /* Polish the bead hole. */ + INIT_LIST_HEAD(&retval->transmitted_list); + INIT_LIST_HEAD(&retval->frag_list); + SCTP_DBG_OBJCNT_INC(chunk); + atomic_set(&retval->refcnt, 1); + +nodata: + return retval; +} + +/* Set chunk->source and dest based on the IP header in chunk->skb. */ +void sctp_init_addrs(struct sctp_chunk *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 struct sctp_chunk *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_STATIC +struct sctp_chunk *sctp_make_chunk(const struct sctp_association *asoc, + __u8 type, __u8 flags, int paylen) +{ + struct sctp_chunk *retval; + sctp_chunkhdr_t *chunk_hdr; + struct sk_buff *skb; + struct sock *sk; + + /* No need to allocate LL here, as this is only a chunk. */ + skb = alloc_skb(WORD_ROUND(sizeof(sctp_chunkhdr_t) + paylen), + GFP_ATOMIC); + if (!skb) + goto nodata; + + /* Make room for the chunk header. */ + chunk_hdr = (sctp_chunkhdr_t *)skb_put(skb, sizeof(sctp_chunkhdr_t)); + chunk_hdr->type = type; + chunk_hdr->flags = flags; + chunk_hdr->length = htons(sizeof(sctp_chunkhdr_t)); + + sk = asoc ? asoc->base.sk : NULL; + retval = sctp_chunkify(skb, asoc, sk); + if (!retval) { + kfree_skb(skb); + goto nodata; + } + + retval->chunk_hdr = chunk_hdr; + retval->chunk_end = ((__u8 *)chunk_hdr) + sizeof(struct sctp_chunkhdr); + + /* Set the skb to the belonging sock for accounting. */ + skb->sk = sk; + + return retval; +nodata: + return NULL; +} + + +/* Release the memory occupied by a chunk. */ +static void sctp_chunk_destroy(struct sctp_chunk *chunk) |