[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: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/sctp.h b/include/linux/sctp.h
index d70df61..f4d717b 100644 (file)
--- a/include/linux/sctp.h
+++ b/include/linux/sctp.h
@@ -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.

diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index 67c91d0..b4812a2 100644 (file)
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -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.

diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index d84e575..71cc204 100644 (file)
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -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;