question about freebsd sctp sctp_asconf_iterator_stcb function.

[黄登辉]

Hi

     I have a little about the following code section of
sctp_asconf_iterator_stcb function.

         if (type == SCTP_ADD_IP_ADDRESS) {
            /* prevent this address from being used as a source */
            sctp_add_local_addr_restricted(stcb, ifa);
        } else if (type == SCTP_DEL_IP_ADDRESS) {
            struct sctp_nets *net;

            TAILQ_FOREACH(net, &stcb->asoc.nets, sctp_next) {
                sctp_rtentry_t *rt;

                /* delete this address if cached */
                if (net->ro._s_addr == ifa) {
                    sctp_free_ifa(net->ro._s_addr);
                    net->ro._s_addr = NULL;
                    net->src_addr_selected = 0;
                    rt = net->ro.ro_rt;
                    if (rt) {
                        RTFREE(rt);
                        net->ro.ro_rt = NULL;
                    }
                    /*
                     * Now we deleted our src address,
                     * should we not also now reset the
                     * cwnd/rto to start as if its a new
                     * address?
                     */
                    stcb->asoc.cc_functions.sctp_set_initial_cc_param(stcb,
net);
                    net->RTO = 0;

                }
            }
        } else if (type == SCTP_SET_PRIM_ADDR) {
            if ((stcb->sctp_ep->sctp_flags & SCTP_PCB_FLAGS_BOUNDALL) == 0)
{
                /* must validate the ifa is in the ep */
                if (sctp_is_addr_in_ep(stcb->sctp_ep, ifa) == 0) {
                    continue;
                }
            } else {
                /* Need to check scopes for this guy */
                if (sctp_is_address_in_scope(ifa,
                    stcb->asoc.ipv4_addr_legal,
                    stcb->asoc.ipv6_addr_legal,
                    stcb->asoc.loopback_scope,
                    stcb->asoc.ipv4_local_scope,
                    stcb->asoc.local_scope,
                    stcb->asoc.site_scope, 0) == 0) {
                    continue;
                }
            }
        }
        /* queue an asconf for this address add/delete */
        if (sctp_is_feature_on(inp, SCTP_PCB_FLAGS_DO_ASCONF) &&
            stcb->asoc.peer_supports_asconf) {
            /* queue an asconf for this addr */
            status = sctp_asconf_queue_add(stcb, ifa, type);
            /*
             * if queued ok, and in the open state, update the
             * count of queued params.  If in the non-open
             * state, these get sent when the assoc goes open.
             */
            if (SCTP_GET_STATE(&stcb->asoc) == SCTP_STATE_OPEN) {
                if (status >= 0) {
                    num_queued++;
                }
            }
        }


should change like this:

        if (sctp_is_feature_on(inp, SCTP_PCB_FLAGS_DO_ASCONF) &&
            stcb->asoc.peer_supports_asconf) {
            if (type == SCTP_ADD_IP_ADDRESS) {
                /* prevent this address from being used as a source */
                sctp_add_local_addr_restricted(stcb, ifa);
            } else if (type == SCTP_DEL_IP_ADDRESS) {
                struct sctp_nets *net;

                TAILQ_FOREACH(net, &stcb->asoc.nets, sctp_next) {
                    sctp_rtentry_t *rt;

                    /* delete this address if cached */
                    if (net->ro._s_addr == ifa) {
                        sctp_free_ifa(net->ro._s_addr);
                        net->ro._s_addr = NULL;
                        net->src_addr_selected = 0;
                        rt = net->ro.ro_rt;
                        if (rt) {
                            RTFREE(rt);
                            net->ro.ro_rt = NULL;
                        }
                        /*
                         * Now we deleted our src address,
                         * should we not also now reset the
                         * cwnd/rto to start as if its a new
                         * address?
                         */

stcb->asoc.cc_functions.sctp_set_initial_cc_param(stcb, net);
                        net->RTO = 0;

                    }
                }
            } else if (type == SCTP_SET_PRIM_ADDR) {
                if ((stcb->sctp_ep->sctp_flags & SCTP_PCB_FLAGS_BOUNDALL) ==
0) {
                    /* must validate the ifa is in the ep */
                    if (sctp_is_addr_in_ep(stcb->sctp_ep, ifa) == 0) {
                        continue;
                    }
                } else {
                    /* Need to check scopes for this guy */
                    if (sctp_is_address_in_scope(ifa,
                        stcb->asoc.ipv4_addr_legal,
                        stcb->asoc.ipv6_addr_legal,
                        stcb->asoc.loopback_scope,
                        stcb->asoc.ipv4_local_scope,
                        stcb->asoc.local_scope,
                        stcb->asoc.site_scope, 0) == 0) {
                        continue;
                    }
                }
            }
            /* queue an asconf for this address add/delete */

                /* queue an asconf for this addr */
                status = sctp_asconf_queue_add(stcb, ifa, type);
                /*
                 * if queued ok, and in the open state, update the
                 * count of queued params.  If in the non-open
                 * state, these get sent when the assoc goes open.
                 */
                if (SCTP_GET_STATE(&stcb->asoc) == SCTP_STATE_OPEN) {
                    if (status >= 0) {
                        num_queued++;
                    }
                }
        }


because  i think put some address into restricted address list is used to
dynamic address configuration.
So first we need to make sure this feature SCTP_PCB_FLAGS_DO_ASCONF is on
and peer endpoint also support this feature.
If i am wrong, experts please give some comments.