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Commit 131a47e3 authored by Vlad Yasevich's avatar Vlad Yasevich Committed by David S. Miller
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[SCTP]: Implement the Supported Extensions Parameter 



SCTP Supported Extenions parameter is specified in Section 4.2.7
of the ADD-IP draft (soon to be RFC).  The parameter is
encoded as:

      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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |     Parameter Type = 0x8008   |      Parameter Length         |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | CHUNK TYPE 1  |  CHUNK TYPE 2 |  CHUNK TYPE 3 |  CHUNK TYPE 4 |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                             ....                              |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | CHUNK TYPE N  |      PAD      |      PAD      |      PAD      |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

It contains a list of chunks that a particular SCTP extension
uses.  Current extensions supported are Partial Reliability
(FWD-TSN) and ADD-IP (ASCONF and ASCONF-ACK).

When implementing new extensions (AUTH, PKT-DROP, etc..), new
chunks need to be added to this parameter.  Parameter processing
would be modified to negotiate support for these new features.

Signed-off-by: default avatarVlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 76c72d4f

include/linux/sctp.h

+9 −0
Original line number Diff line number Diff line
@@ -180,6 +180,9 @@ typedef enum { 
	SCTP_PARAM_SUPPORTED_ADDRESS_TYPES	= __constant_htons(12),

	SCTP_PARAM_ECN_CAPABLE			= __constant_htons(0x8000),



	/* Add-IP: Supported Extensions, Section 4.2 */

	SCTP_PARAM_SUPPORTED_EXT	= __constant_htons(0x8008),



	/* PR-SCTP Sec 3.1 */

	SCTP_PARAM_FWD_TSN_SUPPORT	= __constant_htons(0xc000),
@@ -296,6 +299,12 @@ typedef struct sctp_adaptation_ind_param { 
	__be32 adaptation_ind;

} __attribute__((packed)) sctp_adaptation_ind_param_t;



/* ADDIP Section 4.2.7 Supported Extensions Parameter */

typedef struct sctp_supported_ext_param {

	struct sctp_paramhdr param_hdr;

	__u8 chunks[0];

} __attribute__((packed)) sctp_supported_ext_param_t;



/* RFC 2960.  Section 3.3.3 Initiation Acknowledgement (INIT ACK) (2):

 *   The INIT ACK chunk is used to acknowledge the initiation of an SCTP

 *   association.

include/net/sctp/structs.h

+1 −0
Original line number Diff line number Diff line
@@ -440,6 +440,7 @@ union sctp_params { 
	struct sctp_ipv6addr_param *v6;

	union sctp_addr_param *addr;

	struct sctp_adaptation_ind_param *aind;

	struct sctp_supported_ext_param *ext;

};



/* RFC 2960.  Section 3.3.5 Heartbeat.

net/sctp/sm_make_chunk.c

+89 −2
Original line number Diff line number Diff line
@@ -179,6 +179,9 @@ struct sctp_chunk *sctp_make_init(const struct sctp_association *asoc, 
	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];



	/* RFC 2960 3.3.2 Initiation (INIT) (1)

	 *
@@ -202,11 +205,31 @@ struct sctp_chunk *sctp_make_init(const struct sctp_association *asoc, 


	chunksize = sizeof(init) + addrs_len + SCTP_SAT_LEN(num_types);

	chunksize += sizeof(ecap_param);

	if (sctp_prsctp_enable)

	if (sctp_prsctp_enable) {

		chunksize += sizeof(prsctp_param);

		extensions[num_ext] = SCTP_CID_FWD_TSN;

		num_ext += 1;

	}

	/* 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.

	 *  XXX: We don't support AUTH just yet, so don't list it.  AUTH

	 *  support should add it.

	 */

	if (sctp_addip_enable) {

		extensions[num_ext] = SCTP_CID_ASCONF;

		extensions[num_ext+1] = SCTP_CID_ASCONF_ACK;

		num_ext += 2;

	}



	chunksize += sizeof(aiparam);

	chunksize += vparam_len;



	/* If we have any extensions to report, account for that */

	if (num_ext)

		chunksize += 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
@@ -241,12 +264,27 @@ struct sctp_chunk *sctp_make_init(const struct sctp_association *asoc, 
	sctp_addto_chunk(retval, num_types * sizeof(__u16), &types);



	sctp_addto_chunk(retval, sizeof(ecap_param), &ecap_param);



	/* Add the supported extensions paramter.  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_chunk(retval, num_ext, extensions);

	}



	if (sctp_prsctp_enable)

		sctp_addto_chunk(retval, sizeof(prsctp_param), &prsctp_param);



	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);



nodata:

	kfree(addrs.v);

	return retval;
@@ -264,6 +302,9 @@ struct sctp_chunk *sctp_make_init_ack(const struct sctp_association *asoc, 
	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];



	retval = NULL;
@@ -294,9 +335,19 @@ struct sctp_chunk *sctp_make_init_ack(const struct sctp_association *asoc, 
		chunksize += sizeof(ecap_param);



	/* Tell peer that we'll do PR-SCTP only if peer advertised.  */

	if (asoc->peer.prsctp_capable)

	if (asoc->peer.prsctp_capable) {

		chunksize += sizeof(prsctp_param);

		extensions[num_ext] = SCTP_CID_FWD_TSN;

		num_ext += 1;

	}



	if (sctp_addip_enable) {

		extensions[num_ext] = SCTP_CID_ASCONF;

		extensions[num_ext+1] = SCTP_CID_ASCONF_ACK;

		num_ext += 2;

	}



	chunksize += sizeof(ext_param) + num_ext;

	chunksize += sizeof(aiparam);



	/* Now allocate and fill out the chunk.  */
@@ -314,6 +365,14 @@ struct sctp_chunk *sctp_make_init_ack(const struct sctp_association *asoc, 
	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_chunk(retval, num_ext, extensions);

	}

	if (asoc->peer.prsctp_capable)

		sctp_addto_chunk(retval, sizeof(prsctp_param), &prsctp_param);
@@ -1664,6 +1723,28 @@ static int sctp_process_hn_param(const struct sctp_association *asoc, 
	return 0;

}



static void sctp_process_ext_param(struct sctp_association *asoc,

				    union sctp_params param)

{

	__u16 num_ext = ntohs(param.p->length) - sizeof(sctp_paramhdr_t);

	int i;



	for (i = 0; i < num_ext; i++) {

		switch (param.ext->chunks[i]) {

		    case SCTP_CID_FWD_TSN:

			    if (sctp_prsctp_enable &&

				!asoc->peer.prsctp_capable)

				    asoc->peer.prsctp_capable = 1;

			    break;

		    case SCTP_CID_ASCONF:

		    case SCTP_CID_ASCONF_ACK:

			    /* don't need to do anything for ASCONF */

		    default:

			    break;

		}

	}

}



/* RFC 3.2.1 & the Implementers Guide 2.2.

 *

 * The Parameter Types are encoded such that the
@@ -1780,11 +1861,13 @@ static int sctp_verify_param(const struct sctp_association *asoc, 
	case SCTP_PARAM_UNRECOGNIZED_PARAMETERS:

	case SCTP_PARAM_ECN_CAPABLE:

	case SCTP_PARAM_ADAPTATION_LAYER_IND:

	case SCTP_PARAM_SUPPORTED_EXT:

		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);



	case SCTP_PARAM_FWD_TSN_SUPPORT:

		if (sctp_prsctp_enable)

			break;
@@ -2129,6 +2212,10 @@ static int sctp_process_param(struct sctp_association *asoc, 
		asoc->peer.adaptation_ind = param.aind->adaptation_ind;

		break;



	case SCTP_PARAM_SUPPORTED_EXT:

		sctp_process_ext_param(asoc, param);

		break;



	case SCTP_PARAM_FWD_TSN_SUPPORT:

		if (sctp_prsctp_enable) {

			asoc->peer.prsctp_capable = 1;