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[SCTP]: Implement the Supported Extensions Parameter
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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: Vlad Yasevich <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
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Vlad Yasevich authored and David S. Miller committed Oct 10, 2007
1 parent 76c72d4 commit 131a47e
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Showing 3 changed files with 99 additions and 2 deletions.
9 changes: 9 additions & 0 deletions include/linux/sctp.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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),

Expand Down Expand Up @@ -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.
Expand Down
1 change: 1 addition & 0 deletions include/net/sctp/structs.h
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Original file line number Diff line number Diff line change
Expand Up @@ -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.
Expand Down
91 changes: 89 additions & 2 deletions net/sctp/sm_make_chunk.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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)
*
Expand All @@ -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
Expand Down Expand Up @@ -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;
Expand All @@ -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;

Expand Down Expand Up @@ -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. */
Expand All @@ -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);

Expand Down Expand Up @@ -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
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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;
Expand Down

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