/*
* net/dccp/feat.c
*
- * An implementation of the DCCP protocol
- * Andrea Bittau <a.bittau@cs.ucl.ac.uk>
+ * Feature negotiation for the DCCP protocol (RFC 4340, section 6)
+ *
+ * Copyright (c) 2008 The University of Aberdeen, Scotland, UK
+ * Copyright (c) 2008 Gerrit Renker <gerrit@erg.abdn.ac.uk>
+ * Rewrote from scratch, some bits from earlier code by
+ * Copyright (c) 2005 Andrea Bittau <a.bittau@cs.ucl.ac.uk>
+ *
*
* ASSUMPTIONS
* -----------
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
-
#include <linux/module.h>
-
#include "ccid.h"
#include "feat.h"
-#define DCCP_FEAT_SP_NOAGREE (-123)
+/*
+ * Feature activation handlers.
+ *
+ * These all use an u64 argument, to provide enough room for NN/SP features. At
+ * this stage the negotiated values have been checked to be within their range.
+ */
+static int dccp_hdlr_ccid(struct sock *sk, u64 ccid, bool rx)
+{
+ struct dccp_sock *dp = dccp_sk(sk);
+ struct ccid *new_ccid = ccid_new(ccid, sk, rx, gfp_any());
+
+ if (new_ccid == NULL)
+ return -ENOMEM;
+
+ if (rx) {
+ ccid_hc_rx_delete(dp->dccps_hc_rx_ccid, sk);
+ dp->dccps_hc_rx_ccid = new_ccid;
+ } else {
+ ccid_hc_tx_delete(dp->dccps_hc_tx_ccid, sk);
+ dp->dccps_hc_tx_ccid = new_ccid;
+ }
+ return 0;
+}
+
+static int dccp_hdlr_seq_win(struct sock *sk, u64 seq_win, bool rx)
+{
+ struct dccp_sock *dp = dccp_sk(sk);
+
+ if (rx) {
+ dp->dccps_r_seq_win = seq_win;
+ /* propagate changes to update SWL/SWH */
+ dccp_update_gsr(sk, dp->dccps_gsr);
+ } else {
+ dp->dccps_l_seq_win = seq_win;
+ /* propagate changes to update AWL */
+ dccp_update_gss(sk, dp->dccps_gss);
+ }
+ return 0;
+}
+
+static int dccp_hdlr_ack_ratio(struct sock *sk, u64 ratio, bool rx)
+{
+ if (rx)
+ dccp_sk(sk)->dccps_r_ack_ratio = ratio;
+ else
+ dccp_sk(sk)->dccps_l_ack_ratio = ratio;
+ return 0;
+}
+
+static int dccp_hdlr_ackvec(struct sock *sk, u64 enable, bool rx)
+{
+ struct dccp_sock *dp = dccp_sk(sk);
+
+ if (rx) {
+ if (enable && dp->dccps_hc_rx_ackvec == NULL) {
+ dp->dccps_hc_rx_ackvec = dccp_ackvec_alloc(gfp_any());
+ if (dp->dccps_hc_rx_ackvec == NULL)
+ return -ENOMEM;
+ } else if (!enable) {
+ dccp_ackvec_free(dp->dccps_hc_rx_ackvec);
+ dp->dccps_hc_rx_ackvec = NULL;
+ }
+ }
+ return 0;
+}
+
+static int dccp_hdlr_ndp(struct sock *sk, u64 enable, bool rx)
+{
+ if (!rx)
+ dccp_sk(sk)->dccps_send_ndp_count = (enable > 0);
+ return 0;
+}
+
+/*
+ * Minimum Checksum Coverage is located at the RX side (9.2.1). This means that
+ * `rx' holds when the sending peer informs about his partial coverage via a
+ * ChangeR() option. In the other case, we are the sender and the receiver
+ * announces its coverage via ChangeL() options. The policy here is to honour
+ * such communication by enabling the corresponding partial coverage - but only
+ * if it has not been set manually before; the warning here means that all
+ * packets will be dropped.
+ */
+static int dccp_hdlr_min_cscov(struct sock *sk, u64 cscov, bool rx)
+{
+ struct dccp_sock *dp = dccp_sk(sk);
+
+ if (rx)
+ dp->dccps_pcrlen = cscov;
+ else {
+ if (dp->dccps_pcslen == 0)
+ dp->dccps_pcslen = cscov;
+ else if (cscov > dp->dccps_pcslen)
+ DCCP_WARN("CsCov %u too small, peer requires >= %u\n",
+ dp->dccps_pcslen, (u8)cscov);
+ }
+ return 0;
+}
static const struct {
u8 feat_num; /* DCCPF_xxx */
enum dccp_feat_type rxtx; /* RX or TX */
enum dccp_feat_type reconciliation; /* SP or NN */
u8 default_value; /* as in 6.4 */
+ int (*activation_hdlr)(struct sock *sk, u64 val, bool rx);
/*
* Lookup table for location and type of features (from RFC 4340/4342)
* +--------------------------+----+-----+----+----+---------+-----------+
* +--------------------------+----+-----+----+----+---------+-----------+
*/
} dccp_feat_table[] = {
- { DCCPF_CCID, FEAT_AT_TX, FEAT_SP, 2 },
- { DCCPF_SHORT_SEQNOS, FEAT_AT_TX, FEAT_SP, 0 },
- { DCCPF_SEQUENCE_WINDOW, FEAT_AT_TX, FEAT_NN, 100 },
- { DCCPF_ECN_INCAPABLE, FEAT_AT_RX, FEAT_SP, 0 },
- { DCCPF_ACK_RATIO, FEAT_AT_TX, FEAT_NN, 2 },
- { DCCPF_SEND_ACK_VECTOR, FEAT_AT_RX, FEAT_SP, 0 },
- { DCCPF_SEND_NDP_COUNT, FEAT_AT_TX, FEAT_SP, 0 },
- { DCCPF_MIN_CSUM_COVER, FEAT_AT_RX, FEAT_SP, 0 },
- { DCCPF_DATA_CHECKSUM, FEAT_AT_RX, FEAT_SP, 0 },
- { DCCPF_SEND_LEV_RATE, FEAT_AT_RX, FEAT_SP, 0 },
+ { DCCPF_CCID, FEAT_AT_TX, FEAT_SP, 2, dccp_hdlr_ccid },
+ { DCCPF_SHORT_SEQNOS, FEAT_AT_TX, FEAT_SP, 0, NULL },
+ { DCCPF_SEQUENCE_WINDOW, FEAT_AT_TX, FEAT_NN, 100, dccp_hdlr_seq_win },
+ { DCCPF_ECN_INCAPABLE, FEAT_AT_RX, FEAT_SP, 0, NULL },
+ { DCCPF_ACK_RATIO, FEAT_AT_TX, FEAT_NN, 2, dccp_hdlr_ack_ratio},
+ { DCCPF_SEND_ACK_VECTOR, FEAT_AT_RX, FEAT_SP, 0, dccp_hdlr_ackvec },
+ { DCCPF_SEND_NDP_COUNT, FEAT_AT_TX, FEAT_SP, 0, dccp_hdlr_ndp },
+ { DCCPF_MIN_CSUM_COVER, FEAT_AT_RX, FEAT_SP, 0, dccp_hdlr_min_cscov},
+ { DCCPF_DATA_CHECKSUM, FEAT_AT_RX, FEAT_SP, 0, NULL },
+ { DCCPF_SEND_LEV_RATE, FEAT_AT_RX, FEAT_SP, 0, NULL },
};
#define DCCP_FEAT_SUPPORTED_MAX ARRAY_SIZE(dccp_feat_table)
return idx < 0 ? : dccp_feat_table[idx].default_value;
}
+static int __dccp_feat_activate(struct sock *sk, const int idx,
+ const bool is_local, dccp_feat_val const *fval)
+{
+ bool rx;
+ u64 val;
+
+ if (idx < 0 || idx >= DCCP_FEAT_SUPPORTED_MAX)
+ return -1;
+ if (dccp_feat_table[idx].activation_hdlr == NULL)
+ return 0;
+
+ if (fval == NULL) {
+ val = dccp_feat_table[idx].default_value;
+ } else if (dccp_feat_table[idx].reconciliation == FEAT_SP) {
+ if (fval->sp.vec == NULL) {
+ /*
+ * This can happen when an empty Confirm is sent
+ * for an SP (i.e. known) feature. In this case
+ * we would be using the default anyway.
+ */
+ DCCP_CRIT("Feature #%d undefined: using default", idx);
+ val = dccp_feat_table[idx].default_value;
+ } else {
+ val = fval->sp.vec[0];
+ }
+ } else {
+ val = fval->nn;
+ }
+
+ /* Location is RX if this is a local-RX or remote-TX feature */
+ rx = (is_local == (dccp_feat_table[idx].rxtx == FEAT_AT_RX));
+
+ return dccp_feat_table[idx].activation_hdlr(sk, val, rx);
+}
+
+/* Test for "Req'd" feature (RFC 4340, 6.4) */
+static inline int dccp_feat_must_be_understood(u8 feat_num)
+{
+ return feat_num == DCCPF_CCID || feat_num == DCCPF_SHORT_SEQNOS ||
+ feat_num == DCCPF_SEQUENCE_WINDOW;
+}
+
/* copy constructor, fval must not already contain allocated memory */
static int dccp_feat_clone_sp_val(dccp_feat_val *fval, u8 const *val, u8 len)
{
return -ENOMEM;
}
+/**
+ * dccp_feat_valid_nn_length - Enforce length constraints on NN options
+ * Length is between 0 and %DCCP_OPTVAL_MAXLEN. Used for outgoing packets only,
+ * incoming options are accepted as long as their values are valid.
+ */
+static u8 dccp_feat_valid_nn_length(u8 feat_num)
+{
+ if (feat_num == DCCPF_ACK_RATIO) /* RFC 4340, 11.3 and 6.6.8 */
+ return 2;
+ if (feat_num == DCCPF_SEQUENCE_WINDOW) /* RFC 4340, 7.5.2 and 6.5 */
+ return 6;
+ return 0;
+}
+
static u8 dccp_feat_is_valid_nn_val(u8 feat_num, u64 val)
{
switch (feat_num) {
}
/**
+ * dccp_feat_insert_opts - Generate FN options from current list state
+ * @skb: next sk_buff to be sent to the peer
+ * @dp: for client during handshake and general negotiation
+ * @dreq: used by the server only (all Changes/Confirms in LISTEN/RESPOND)
+ */
+int dccp_feat_insert_opts(struct dccp_sock *dp, struct dccp_request_sock *dreq,
+ struct sk_buff *skb)
+{
+ struct list_head *fn = dreq ? &dreq->dreq_featneg : &dp->dccps_featneg;
+ struct dccp_feat_entry *pos, *next;
+ u8 opt, type, len, *ptr, nn_in_nbo[DCCP_OPTVAL_MAXLEN];
+ bool rpt;
+
+ /* put entries into @skb in the order they appear in the list */
+ list_for_each_entry_safe_reverse(pos, next, fn, node) {
+ opt = dccp_feat_genopt(pos);
+ type = dccp_feat_type(pos->feat_num);
+ rpt = false;
+
+ if (pos->empty_confirm) {
+ len = 0;
+ ptr = NULL;
+ } else {
+ if (type == FEAT_SP) {
+ len = pos->val.sp.len;
+ ptr = pos->val.sp.vec;
+ rpt = pos->needs_confirm;
+ } else if (type == FEAT_NN) {
+ len = dccp_feat_valid_nn_length(pos->feat_num);
+ ptr = nn_in_nbo;
+ dccp_encode_value_var(pos->val.nn, ptr, len);
+ } else {
+ DCCP_BUG("unknown feature %u", pos->feat_num);
+ return -1;
+ }
+ }
+
+ if (dccp_insert_fn_opt(skb, opt, pos->feat_num, ptr, len, rpt))
+ return -1;
+ if (pos->needs_mandatory && dccp_insert_option_mandatory(skb))
+ return -1;
+ /*
+ * Enter CHANGING after transmitting the Change option (6.6.2).
+ */
+ if (pos->state == FEAT_INITIALISING)
+ pos->state = FEAT_CHANGING;
+ }
+ return 0;
+}
+
+/**
* __feat_register_nn - Register new NN value on socket
* @fn: feature-negotiation list to register with
* @feat: an NN feature from %dccp_feature_numbers
!dccp_feat_sp_list_ok(feat, sp_val, sp_len))
return -EINVAL;
+ /* Avoid negotiating alien CCIDs by only advertising supported ones */
+ if (feat == DCCPF_CCID && !ccid_support_check(sp_val, sp_len))
+ return -EOPNOTSUPP;
+
if (dccp_feat_clone_sp_val(&fval, sp_val, sp_len))
return -ENOMEM;
return dccp_feat_push_change(fn, feat, is_local, mandatory, &fval);
}
-int dccp_feat_change(struct dccp_minisock *dmsk, u8 type, u8 feature,
- u8 *val, u8 len, gfp_t gfp)
-{
- struct dccp_opt_pend *opt;
-
- dccp_feat_debug(type, feature, *val);
-
- if (len > 3) {
- DCCP_WARN("invalid length %d\n", len);
+/**
+ * dccp_feat_register_sp - Register requests to change SP feature values
+ * @sk: client or listening socket
+ * @feat: one of %dccp_feature_numbers
+ * @is_local: whether the local (1) or remote (0) @feat is meant
+ * @list: array of preferred values, in descending order of preference
+ * @len: length of @list in bytes
+ */
+int dccp_feat_register_sp(struct sock *sk, u8 feat, u8 is_local,
+ u8 const *list, u8 len)
+{ /* any changes must be registered before establishing the connection */
+ if (sk->sk_state != DCCP_CLOSED)
+ return -EISCONN;
+ if (dccp_feat_type(feat) != FEAT_SP)
return -EINVAL;
- }
- /* XXX add further sanity checks */
-
- /* check if that feature is already being negotiated */
- list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
- /* ok we found a negotiation for this option already */
- if (opt->dccpop_feat == feature && opt->dccpop_type == type) {
- dccp_pr_debug("Replacing old\n");
- /* replace */
- BUG_ON(opt->dccpop_val == NULL);
- kfree(opt->dccpop_val);
- opt->dccpop_val = val;
- opt->dccpop_len = len;
- opt->dccpop_conf = 0;
- return 0;
- }
- }
-
- /* negotiation for a new feature */
- opt = kmalloc(sizeof(*opt), gfp);
- if (opt == NULL)
- return -ENOMEM;
-
- opt->dccpop_type = type;
- opt->dccpop_feat = feature;
- opt->dccpop_len = len;
- opt->dccpop_val = val;
- opt->dccpop_conf = 0;
- opt->dccpop_sc = NULL;
-
- BUG_ON(opt->dccpop_val == NULL);
-
- list_add_tail(&opt->dccpop_node, &dmsk->dccpms_pending);
- return 0;
+ return __feat_register_sp(&dccp_sk(sk)->dccps_featneg, feat, is_local,
+ 0, list, len);
}
-EXPORT_SYMBOL_GPL(dccp_feat_change);
-
-static int dccp_feat_update_ccid(struct sock *sk, u8 type, u8 new_ccid_nr)
+/* Analogous to dccp_feat_register_sp(), but for non-negotiable values */
+int dccp_feat_register_nn(struct sock *sk, u8 feat, u64 val)
{
- struct dccp_sock *dp = dccp_sk(sk);
- struct dccp_minisock *dmsk = dccp_msk(sk);
- /* figure out if we are changing our CCID or the peer's */
- const int rx = type == DCCPO_CHANGE_R;
- const u8 ccid_nr = rx ? dmsk->dccpms_rx_ccid : dmsk->dccpms_tx_ccid;
- struct ccid *new_ccid;
-
- /* Check if nothing is being changed. */
- if (ccid_nr == new_ccid_nr)
- return 0;
-
- new_ccid = ccid_new(new_ccid_nr, sk, rx, GFP_ATOMIC);
- if (new_ccid == NULL)
- return -ENOMEM;
-
- if (rx) {
- ccid_hc_rx_delete(dp->dccps_hc_rx_ccid, sk);
- dp->dccps_hc_rx_ccid = new_ccid;
- dmsk->dccpms_rx_ccid = new_ccid_nr;
- } else {
- ccid_hc_tx_delete(dp->dccps_hc_tx_ccid, sk);
- dp->dccps_hc_tx_ccid = new_ccid;
- dmsk->dccpms_tx_ccid = new_ccid_nr;
- }
-
- return 0;
+ /* any changes must be registered before establishing the connection */
+ if (sk->sk_state != DCCP_CLOSED)
+ return -EISCONN;
+ if (dccp_feat_type(feat) != FEAT_NN)
+ return -EINVAL;
+ return __feat_register_nn(&dccp_sk(sk)->dccps_featneg, feat, 0, val);
}
-static int dccp_feat_update(struct sock *sk, u8 type, u8 feat, u8 val)
+/*
+ * Tracking features whose value depend on the choice of CCID
+ *
+ * This is designed with an extension in mind so that a list walk could be done
+ * before activating any features. However, the existing framework was found to
+ * work satisfactorily up until now, the automatic verification is left open.
+ * When adding new CCIDs, add a corresponding dependency table here.
+ */
+static const struct ccid_dependency *dccp_feat_ccid_deps(u8 ccid, bool is_local)
{
- dccp_feat_debug(type, feat, val);
-
- switch (feat) {
- case DCCPF_CCID:
- return dccp_feat_update_ccid(sk, type, val);
+ static const struct ccid_dependency ccid2_dependencies[2][2] = {
+ /*
+ * CCID2 mandates Ack Vectors (RFC 4341, 4.): as CCID is a TX
+ * feature and Send Ack Vector is an RX feature, `is_local'
+ * needs to be reversed.
+ */
+ { /* Dependencies of the receiver-side (remote) CCID2 */
+ {
+ .dependent_feat = DCCPF_SEND_ACK_VECTOR,
+ .is_local = true,
+ .is_mandatory = true,
+ .val = 1
+ },
+ { 0, 0, 0, 0 }
+ },
+ { /* Dependencies of the sender-side (local) CCID2 */
+ {
+ .dependent_feat = DCCPF_SEND_ACK_VECTOR,
+ .is_local = false,
+ .is_mandatory = true,
+ .val = 1
+ },
+ { 0, 0, 0, 0 }
+ }
+ };
+ static const struct ccid_dependency ccid3_dependencies[2][5] = {
+ { /*
+ * Dependencies of the receiver-side CCID3
+ */
+ { /* locally disable Ack Vectors */
+ .dependent_feat = DCCPF_SEND_ACK_VECTOR,
+ .is_local = true,
+ .is_mandatory = false,
+ .val = 0
+ },
+ { /* see below why Send Loss Event Rate is on */
+ .dependent_feat = DCCPF_SEND_LEV_RATE,
+ .is_local = true,
+ .is_mandatory = true,
+ .val = 1
+ },
+ { /* NDP Count is needed as per RFC 4342, 6.1.1 */
+ .dependent_feat = DCCPF_SEND_NDP_COUNT,
+ .is_local = false,
+ .is_mandatory = true,
+ .val = 1
+ },
+ { 0, 0, 0, 0 },
+ },
+ { /*
+ * CCID3 at the TX side: we request that the HC-receiver
+ * will not send Ack Vectors (they will be ignored, so
+ * Mandatory is not set); we enable Send Loss Event Rate
+ * (Mandatory since the implementation does not support
+ * the Loss Intervals option of RFC 4342, 8.6).
+ * The last two options are for peer's information only.
+ */
+ {
+ .dependent_feat = DCCPF_SEND_ACK_VECTOR,
+ .is_local = false,
+ .is_mandatory = false,
+ .val = 0
+ },
+ {
+ .dependent_feat = DCCPF_SEND_LEV_RATE,
+ .is_local = false,
+ .is_mandatory = true,
+ .val = 1
+ },
+ { /* this CCID does not support Ack Ratio */
+ .dependent_feat = DCCPF_ACK_RATIO,
+ .is_local = true,
+ .is_mandatory = false,
+ .val = 0
+ },
+ { /* tell receiver we are sending NDP counts */
+ .dependent_feat = DCCPF_SEND_NDP_COUNT,
+ .is_local = true,
+ .is_mandatory = false,
+ .val = 1
+ },
+ { 0, 0, 0, 0 }
+ }
+ };
+ switch (ccid) {
+ case DCCPC_CCID2:
+ return ccid2_dependencies[is_local];
+ case DCCPC_CCID3:
+ return ccid3_dependencies[is_local];
default:
- dccp_pr_debug("UNIMPLEMENTED: %s(%d, ...)\n",
- dccp_feat_typename(type), feat);
- break;
+ return NULL;
}
- return 0;
}
-static int dccp_feat_reconcile(struct sock *sk, struct dccp_opt_pend *opt,
- u8 *rpref, u8 rlen)
+/**
+ * dccp_feat_propagate_ccid - Resolve dependencies of features on choice of CCID
+ * @fn: feature-negotiation list to update
+ * @id: CCID number to track
+ * @is_local: whether TX CCID (1) or RX CCID (0) is meant
+ * This function needs to be called after registering all other features.
+ */
+static int dccp_feat_propagate_ccid(struct list_head *fn, u8 id, bool is_local)
{
- struct dccp_sock *dp = dccp_sk(sk);
- u8 *spref, slen, *res = NULL;
- int i, j, rc, agree = 1;
+ const struct ccid_dependency *table = dccp_feat_ccid_deps(id, is_local);
+ int i, rc = (table == NULL);
+
+ for (i = 0; rc == 0 && table[i].dependent_feat != DCCPF_RESERVED; i++)
+ if (dccp_feat_type(table[i].dependent_feat) == FEAT_SP)
+ rc = __feat_register_sp(fn, table[i].dependent_feat,
+ table[i].is_local,
+ table[i].is_mandatory,
+ &table[i].val, 1);
+ else
+ rc = __feat_register_nn(fn, table[i].dependent_feat,
+ table[i].is_mandatory,
+ table[i].val);
+ return rc;
+}
- BUG_ON(rpref == NULL);
+/**
+ * dccp_feat_finalise_settings - Finalise settings before starting negotiation
+ * @dp: client or listening socket (settings will be inherited)
+ * This is called after all registrations (socket initialisation, sysctls, and
+ * sockopt calls), and before sending the first packet containing Change options
+ * (ie. client-Request or server-Response), to ensure internal consistency.
+ */
+int dccp_feat_finalise_settings(struct dccp_sock *dp)
+{
+ struct list_head *fn = &dp->dccps_featneg;
+ struct dccp_feat_entry *entry;
+ int i = 2, ccids[2] = { -1, -1 };
- /* check if we are the black sheep */
- if (dp->dccps_role == DCCP_ROLE_CLIENT) {
- spref = rpref;
- slen = rlen;
- rpref = opt->dccpop_val;
- rlen = opt->dccpop_len;
- } else {
- spref = opt->dccpop_val;
- slen = opt->dccpop_len;
- }
/*
- * Now we have server preference list in spref and client preference in
- * rpref
+ * Propagating CCIDs:
+ * 1) not useful to propagate CCID settings if this host advertises more
+ * than one CCID: the choice of CCID may still change - if this is
+ * the client, or if this is the server and the client sends
+ * singleton CCID values.
+ * 2) since is that propagate_ccid changes the list, we defer changing
+ * the sorted list until after the traversal.
*/
- BUG_ON(spref == NULL);
- BUG_ON(rpref == NULL);
-
- /* FIXME sanity check vals */
-
- /* Are values in any order? XXX Lame "algorithm" here */
- for (i = 0; i < slen; i++) {
- for (j = 0; j < rlen; j++) {
- if (spref[i] == rpref[j]) {
- res = &spref[i];
- break;
- }
- }
- if (res)
- break;
- }
-
- /* we didn't agree on anything */
- if (res == NULL) {
- /* confirm previous value */
- switch (opt->dccpop_feat) {
- case DCCPF_CCID:
- /* XXX did i get this right? =P */
- if (opt->dccpop_type == DCCPO_CHANGE_L)
- res = &dccp_msk(sk)->dccpms_tx_ccid;
- else
- res = &dccp_msk(sk)->dccpms_rx_ccid;
- break;
-
- default:
- DCCP_BUG("Fell through, feat=%d", opt->dccpop_feat);
- /* XXX implement res */
- return -EFAULT;
- }
-
- dccp_pr_debug("Don't agree... reconfirming %d\n", *res);
- agree = 0; /* this is used for mandatory options... */
- }
-
- /* need to put result and our preference list */
- rlen = 1 + opt->dccpop_len;
- rpref = kmalloc(rlen, GFP_ATOMIC);
- if (rpref == NULL)
- return -ENOMEM;
-
- *rpref = *res;
- memcpy(&rpref[1], opt->dccpop_val, opt->dccpop_len);
-
- /* put it in the "confirm queue" */
- if (opt->dccpop_sc == NULL) {
- opt->dccpop_sc = kmalloc(sizeof(*opt->dccpop_sc), GFP_ATOMIC);
- if (opt->dccpop_sc == NULL) {
- kfree(rpref);
- return -ENOMEM;
- }
- } else {
- /* recycle the confirm slot */
- BUG_ON(opt->dccpop_sc->dccpoc_val == NULL);
- kfree(opt->dccpop_sc->dccpoc_val);
- dccp_pr_debug("recycling confirm slot\n");
- }
- memset(opt->dccpop_sc, 0, sizeof(*opt->dccpop_sc));
+ list_for_each_entry(entry, fn, node)
+ if (entry->feat_num == DCCPF_CCID && entry->val.sp.len == 1)
+ ccids[entry->is_local] = entry->val.sp.vec[0];
+ while (i--)
+ if (ccids[i] > 0 && dccp_feat_propagate_ccid(fn, ccids[i], i))
+ return -1;
+ return 0;
+}
- opt->dccpop_sc->dccpoc_val = rpref;
- opt->dccpop_sc->dccpoc_len = rlen;
+/**
+ * dccp_feat_server_ccid_dependencies - Resolve CCID-dependent features
+ * It is the server which resolves the dependencies once the CCID has been
+ * fully negotiated. If no CCID has been negotiated, it uses the default CCID.
+ */
+int dccp_feat_server_ccid_dependencies(struct dccp_request_sock *dreq)
+{
+ struct list_head *fn = &dreq->dreq_featneg;
+ struct dccp_feat_entry *entry;
+ u8 is_local, ccid;
- /* update the option on our side [we are about to send the confirm] */
- rc = dccp_feat_update(sk, opt->dccpop_type, opt->dccpop_feat, *res);
- if (rc) {
- kfree(opt->dccpop_sc->dccpoc_val);
- kfree(opt->dccpop_sc);
- opt->dccpop_sc = NULL;
- return rc;
- }
+ for (is_local = 0; is_local <= 1; is_local++) {
+ entry = dccp_feat_list_lookup(fn, DCCPF_CCID, is_local);
- dccp_pr_debug("Will confirm %d\n", *rpref);
+ if (entry != NULL && !entry->empty_confirm)
+ ccid = entry->val.sp.vec[0];
+ else
+ ccid = dccp_feat_default_value(DCCPF_CCID);
- /* say we want to change to X but we just got a confirm X, suppress our
- * change
- */
- if (!opt->dccpop_conf) {
- if (*opt->dccpop_val == *res)
- opt->dccpop_conf = 1;
- dccp_pr_debug("won't ask for change of same feature\n");
+ if (dccp_feat_propagate_ccid(fn, ccid, is_local))
+ return -1;
}
-
- return agree ? 0 : DCCP_FEAT_SP_NOAGREE; /* used for mandatory opts */
+ return 0;
}
-static int dccp_feat_sp(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len)
+/* Select the first entry in @servlist that also occurs in @clilist (6.3.1) */
+static int dccp_feat_preflist_match(u8 *servlist, u8 slen, u8 *clilist, u8 clen)
{
- struct dccp_minisock *dmsk = dccp_msk(sk);
- struct dccp_opt_pend *opt;
- int rc = 1;
- u8 t;
+ u8 c, s;
- /*
- * We received a CHANGE. We gotta match it against our own preference
- * list. If we got a CHANGE_R it means it's a change for us, so we need
- * to compare our CHANGE_L list.
- */
- if (type == DCCPO_CHANGE_L)
- t = DCCPO_CHANGE_R;
- else
- t = DCCPO_CHANGE_L;
+ for (s = 0; s < slen; s++)
+ for (c = 0; c < clen; c++)
+ if (servlist[s] == clilist[c])
+ return servlist[s];
+ return -1;
+}
- /* find our preference list for this feature */
- list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
- if (opt->dccpop_type != t || opt->dccpop_feat != feature)
- continue;
+/**
+ * dccp_feat_prefer - Move preferred entry to the start of array
+ * Reorder the @array_len elements in @array so that @preferred_value comes
+ * first. Returns >0 to indicate that @preferred_value does occur in @array.
+ */
+static u8 dccp_feat_prefer(u8 preferred_value, u8 *array, u8 array_len)
+{
+ u8 i, does_occur = 0;
- /* find the winner from the two preference lists */
- rc = dccp_feat_reconcile(sk, opt, val, len);
- break;
+ if (array != NULL) {
+ for (i = 0; i < array_len; i++)
+ if (array[i] == preferred_value) {
+ array[i] = array[0];
+ does_occur++;
+ }
+ if (does_occur)
+ array[0] = preferred_value;
}
-
- /* We didn't deal with the change. This can happen if we have no
- * preference list for the feature. In fact, it just shouldn't
- * happen---if we understand a feature, we should have a preference list
- * with at least the default value.
- */
- BUG_ON(rc == 1);
-
- return rc;
+ return does_occur;
}
-static int dccp_feat_nn(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len)
+/**
+ * dccp_feat_reconcile - Reconcile SP preference lists
+ * @fval: SP list to reconcile into
+ * @arr: received SP preference list
+ * @len: length of @arr in bytes
+ * @is_server: whether this side is the server (and @fv is the server's list)
+ * @reorder: whether to reorder the list in @fv after reconciling with @arr
+ * When successful, > 0 is returned and the reconciled list is in @fval.
+ * A value of 0 means that negotiation failed (no shared entry).
+ */
+static int dccp_feat_reconcile(dccp_feat_val *fv, u8 *arr, u8 len,
+ bool is_server, bool reorder)
{
- struct dccp_opt_pend *opt;
- struct dccp_minisock *dmsk = dccp_msk(sk);
- u8 *copy;
int rc;
- /* NN features must be Change L (sec. 6.3.2) */
- if (type != DCCPO_CHANGE_L) {
- dccp_pr_debug("received %s for NN feature %d\n",
- dccp_feat_typename(type), feature);
- return -EFAULT;
- }
-
- /* XXX sanity check opt val */
-
- /* copy option so we can confirm it */
- opt = kzalloc(sizeof(*opt), GFP_ATOMIC);
- if (opt == NULL)
- return -ENOMEM;
-
- copy = kmemdup(val, len, GFP_ATOMIC);
- if (copy == NULL) {
- kfree(opt);
- return -ENOMEM;
+ if (!fv->sp.vec || !arr) {
+ DCCP_CRIT("NULL feature value or array");
+ return 0;
}
- opt->dccpop_type = DCCPO_CONFIRM_R; /* NN can only confirm R */
- opt->dccpop_feat = feature;
- opt->dccpop_val = copy;
- opt->dccpop_len = len;
+ if (is_server)
+ rc = dccp_feat_preflist_match(fv->sp.vec, fv->sp.len, arr, len);
+ else
+ rc = dccp_feat_preflist_match(arr, len, fv->sp.vec, fv->sp.len);
- /* change feature */
- rc = dccp_feat_update(sk, type, feature, *val);
- if (rc) {
- kfree(opt->dccpop_val);
- kfree(opt);
+ if (!reorder)
return rc;
- }
-
- dccp_feat_debug(type, feature, *copy);
-
- list_add_tail(&opt->dccpop_node, &dmsk->dccpms_conf);
+ if (rc < 0)
+ return 0;
- return 0;
+ /*
+ * Reorder list: used for activating features and in dccp_insert_fn_opt.
+ */
+ return dccp_feat_prefer(rc, fv->sp.vec, fv->sp.len);
}
-static void dccp_feat_empty_confirm(struct dccp_minisock *dmsk,
- u8 type, u8 feature)
+/**
+ * dccp_feat_change_recv - Process incoming ChangeL/R options
+ * @fn: feature-negotiation list to update
+ * @is_mandatory: whether the Change was preceded by a Mandatory option
+ * @opt: %DCCPO_CHANGE_L or %DCCPO_CHANGE_R
+ * @feat: one of %dccp_feature_numbers
+ * @val: NN value or SP value/preference list
+ * @len: length of @val in bytes
+ * @server: whether this node is the server (1) or the client (0)
+ */
+static u8 dccp_feat_change_recv(struct list_head *fn, u8 is_mandatory, u8 opt,
+ u8 feat, u8 *val, u8 len, const bool server)
{
- /* XXX check if other confirms for that are queued and recycle slot */
- struct dccp_opt_pend *opt = kzalloc(sizeof(*opt), GFP_ATOMIC);
-
- if (opt == NULL) {
- /* XXX what do we do? Ignoring should be fine. It's a change
- * after all =P
- */
- return;
- }
-
- switch (type) {
- case DCCPO_CHANGE_L:
- opt->dccpop_type = DCCPO_CONFIRM_R;
- break;
- case DCCPO_CHANGE_R:
- opt->dccpop_type = DCCPO_CONFIRM_L;
- break;
- default:
- DCCP_WARN("invalid type %d\n", type);
- kfree(opt);
- return;
- }
- opt->dccpop_feat = feature;
- opt->dccpop_val = NULL;
- opt->dccpop_len = 0;
-
- /* change feature */
- dccp_pr_debug("Empty %s(%d)\n", dccp_feat_typename(type), feature);
+ u8 defval, type = dccp_feat_type(feat);
+ const bool local = (opt == DCCPO_CHANGE_R);
+ struct dccp_feat_entry *entry;
+ dccp_feat_val fval;
- list_add_tail(&opt->dccpop_node, &dmsk->dccpms_conf);
-}
+ if (len == 0 || type == FEAT_UNKNOWN) /* 6.1 and 6.6.8 */
+ goto unknown_feature_or_value;
-static void dccp_feat_flush_confirm(struct sock *sk)
-{
- struct dccp_minisock *dmsk = dccp_msk(sk);
- /* Check if there is anything to confirm in the first place */
- int yes = !list_empty(&dmsk->dccpms_conf);
+ /*
+ * Negotiation of NN features: Change R is invalid, so there is no
+ * simultaneous negotiation; hence we do not look up in the list.
+ */
+ if (type == FEAT_NN) {
+ if (local || len > sizeof(fval.nn))
+ goto unknown_feature_or_value;
- if (!yes) {
- struct dccp_opt_pend *opt;
+ /* 6.3.2: "The feature remote MUST accept any valid value..." */
+ fval.nn = dccp_decode_value_var(val, len);
+ if (!dccp_feat_is_valid_nn_val(feat, fval.nn))
+ goto unknown_feature_or_value;
- list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
- if (opt->dccpop_conf) {
- yes = 1;
- break;
- }
- }
+ return dccp_feat_push_confirm(fn, feat, local, &fval);
}
- if (!yes)
- return;
+ /*
+ * Unidirectional/simultaneous negotiation of SP features (6.3.1)
+ */
+ entry = dccp_feat_list_lookup(fn, feat, local);
+ if (entry == NULL) {
+ /*
+ * No particular preferences have been registered. We deal with
+ * this situation by assuming that all valid values are equally
+ * acceptable, and apply the following checks:
+ * - if the peer's list is a singleton, we accept a valid value;
+ * - if we are the server, we first try to see if the peer (the
+ * client) advertises the default value. If yes, we use it,
+ * otherwise we accept the preferred value;
+ * - else if we are the client, we use the first list element.
+ */
+ if (dccp_feat_clone_sp_val(&fval, val, 1))
+ return DCCP_RESET_CODE_TOO_BUSY;
+
+ if (len > 1 && server) {
+ defval = dccp_feat_default_value(feat);
+ if (dccp_feat_preflist_match(&defval, 1, val, len) > -1)
+ fval.sp.vec[0] = defval;
+ } else if (!dccp_feat_is_valid_sp_val(feat, fval.sp.vec[0])) {
+ kfree(fval.sp.vec);
+ goto unknown_feature_or_value;
+ }
- /* OK there is something to confirm... */
- /* XXX check if packet is in flight? Send delayed ack?? */
- if (sk->sk_state == DCCP_OPEN)
- dccp_send_ack(sk);
-}
+ /* Treat unsupported CCIDs like invalid values */
+ if (feat == DCCPF_CCID && !ccid_support_check(fval.sp.vec, 1)) {
+ kfree(fval.sp.vec);
+ goto not_valid_or_not_known;
+ }
-int dccp_feat_change_recv(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len)
-{
- int rc;
+ return dccp_feat_push_confirm(fn, feat, local, &fval);
- /* Ignore Change requests other than during connection setup */
- if (sk->sk_state != DCCP_LISTEN && sk->sk_state != DCCP_REQUESTING)
+ } else if (entry->state == FEAT_UNSTABLE) { /* 6.6.2 */
return 0;
- dccp_feat_debug(type, feature, *val);
-
- /* figure out if it's SP or NN feature */
- switch (feature) {
- /* deal with SP features */
- case DCCPF_CCID:
- rc = dccp_feat_sp(sk, type, feature, val, len);
- break;
-
- /* deal with NN features */
- case DCCPF_ACK_RATIO:
- rc = dccp_feat_nn(sk, type, feature, val, len);
- break;
-
- /* XXX implement other features */
- default:
- dccp_pr_debug("UNIMPLEMENTED: not handling %s(%d, ...)\n",
- dccp_feat_typename(type), feature);
- rc = -EFAULT;
- break;
}
- /* check if there were problems changing features */
- if (rc) {
- /* If we don't agree on SP, we sent a confirm for old value.
- * However we propagate rc to caller in case option was
- * mandatory
+ if (dccp_feat_reconcile(&entry->val, val, len, server, true)) {
+ entry->empty_confirm = 0;
+ } else if (is_mandatory) {
+ return DCCP_RESET_CODE_MANDATORY_ERROR;
+ } else if (entry->state == FEAT_INITIALISING) {
+ /*
+ * Failed simultaneous negotiation (server only): try to `save'
+ * the connection by checking whether entry contains the default
+ * value for @feat. If yes, send an empty Confirm to signal that
+ * the received Change was not understood - which implies using
+ * the default value.
+ * If this also fails, we use Reset as the last resort.
*/
- if (rc != DCCP_FEAT_SP_NOAGREE)
- dccp_feat_empty_confirm(dccp_msk(sk), type, feature);
+ WARN_ON(!server);
+ defval = dccp_feat_default_value(feat);
+ if (!dccp_feat_reconcile(&entry->val, &defval, 1, server, true))
+ return DCCP_RESET_CODE_OPTION_ERROR;
+ entry->empty_confirm = 1;
}
+ entry->needs_confirm = 1;
+ entry->needs_mandatory = 0;
+ entry->state = FEAT_STABLE;
+ return 0;
- /* generate the confirm [if required] */
- dccp_feat_flush_confirm(sk);
+unknown_feature_or_value:
+ if (!is_mandatory)
+ return dccp_push_empty_confirm(fn, feat, local);
- return rc;
+not_valid_or_not_known:
+ return is_mandatory ? DCCP_RESET_CODE_MANDATORY_ERROR
+ : DCCP_RESET_CODE_OPTION_ERROR;
}
-EXPORT_SYMBOL_GPL(dccp_feat_change_recv);
-
-int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature,
- u8 *val, u8 len)
+/**
+ * dccp_feat_confirm_recv - Process received Confirm options
+ * @fn: feature-negotiation list to update
+ * @is_mandatory: whether @opt was preceded by a Mandatory option
+ * @opt: %DCCPO_CONFIRM_L or %DCCPO_CONFIRM_R
+ * @feat: one of %dccp_feature_numbers
+ * @val: NN value or SP value/preference list
+ * @len: length of @val in bytes
+ * @server: whether this node is server (1) or client (0)
+ */
+static u8 dccp_feat_confirm_recv(struct list_head *fn, u8 is_mandatory, u8 opt,
+ u8 feat, u8 *val, u8 len, const bool server)
{
- u8 t;
- struct dccp_opt_pend *opt;
- struct dccp_minisock *dmsk = dccp_msk(sk);
- int found = 0;
- int all_confirmed = 1;
+ u8 *plist, plen, type = dccp_feat_type(feat);
+ const bool local = (opt == DCCPO_CONFIRM_R);
+ struct dccp_feat_entry *entry = dccp_feat_list_lookup(fn, feat, local);
+
+ if (entry == NULL) { /* nothing queued: ignore or handle error */
+ if (is_mandatory && type == FEAT_UNKNOWN)
+ return DCCP_RESET_CODE_MANDATORY_ERROR;
- /* Ignore Confirm options other than during connection setup */
- if (sk->sk_state != DCCP_LISTEN && sk->sk_state != DCCP_REQUESTING)
+ if (!local && type == FEAT_NN) /* 6.3.2 */
+ goto confirmation_failed;
return 0;
- dccp_feat_debug(type, feature, *val);
+ }
- /* locate our change request */
- switch (type) {
- case DCCPO_CONFIRM_L: t = DCCPO_CHANGE_R; break;
- case DCCPO_CONFIRM_R: t = DCCPO_CHANGE_L; break;
- default: DCCP_WARN("invalid type %d\n", type);
- return 1;
+ if (entry->state != FEAT_CHANGING) /* 6.6.2 */
+ return 0;
+ if (len == 0) {
+ if (dccp_feat_must_be_understood(feat)) /* 6.6.7 */
+ goto confirmation_failed;
+ /*
+ * Empty Confirm during connection setup: this means reverting
+ * to the `old' value, which in this case is the default. Since
+ * we handle default values automatically when no other values
+ * have been set, we revert to the old value by removing this
+ * entry from the list.
+ */
+ dccp_feat_list_pop(entry);
+ return 0;
}
- /* XXX sanity check feature value */
-
- list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
- if (!opt->dccpop_conf && opt->dccpop_type == t &&
- opt->dccpop_feat == feature) {
- found = 1;
- dccp_pr_debug("feature %d found\n", opt->dccpop_feat);
- /* XXX do sanity check */
+ if (type == FEAT_NN) {
+ if (len > sizeof(entry->val.nn))
+ goto confirmation_failed;
- opt->dccpop_conf = 1;
+ if (entry->val.nn == dccp_decode_value_var(val, len))
+ goto confirmation_succeeded;
- /* We got a confirmation---change the option */
- dccp_feat_update(sk, opt->dccpop_type,
- opt->dccpop_feat, *val);
+ DCCP_WARN("Bogus Confirm for non-existing value\n");
+ goto confirmation_failed;
+ }
- /* XXX check the return value of dccp_feat_update */
- break;
- }
+ /*
+ * Parsing SP Confirms: the first element of @val is the preferred
+ * SP value which the peer confirms, the remainder depends on @len.
+ * Note that only the confirmed value need to be a valid SP value.
+ */
+ if (!dccp_feat_is_valid_sp_val(feat, *val))
+ goto confirmation_failed;
+
+ if (len == 1) { /* peer didn't supply a preference list */
+ plist = val;
+ plen = len;
+ } else { /* preferred value + preference list */
+ plist = val + 1;
+ plen = len - 1;
+ }
- if (!opt->dccpop_conf)
- all_confirmed = 0;
+ /* Check whether the peer got the reconciliation right (6.6.8) */
+ if (dccp_feat_reconcile(&entry->val, plist, plen, server, 0) != *val) {
+ DCCP_WARN("Confirm selected the wrong value %u\n", *val);
+ return DCCP_RESET_CODE_OPTION_ERROR;
}
+ entry->val.sp.vec[0] = *val;
- if (!found)
- dccp_pr_debug("%s(%d, ...) never requested\n",
- dccp_feat_typename(type), feature);
+confirmation_succeeded:
+ entry->state = FEAT_STABLE;
return 0;
-}
-EXPORT_SYMBOL_GPL(dccp_feat_confirm_recv);
+confirmation_failed:
+ DCCP_WARN("Confirmation failed\n");
+ return is_mandatory ? DCCP_RESET_CODE_MANDATORY_ERROR
+ : DCCP_RESET_CODE_OPTION_ERROR;
+}
-void dccp_feat_clean(struct dccp_minisock *dmsk)
+/**
+ * dccp_feat_parse_options - Process Feature-Negotiation Options
+ * @sk: for general use and used by the client during connection setup
+ * @dreq: used by the server during connection setup
+ * @mandatory: whether @opt was preceded by a Mandatory option
+ * @opt: %DCCPO_CHANGE_L | %DCCPO_CHANGE_R | %DCCPO_CONFIRM_L | %DCCPO_CONFIRM_R
+ * @feat: one of %dccp_feature_numbers
+ * @val: value contents of @opt
+ * @len: length of @val in bytes
+ * Returns 0 on success, a Reset code for ending the connection otherwise.
+ */
+int dccp_feat_parse_options(struct sock *sk, struct dccp_request_sock *dreq,
+ u8 mandatory, u8 opt, u8 feat, u8 *val, u8 len)
{
- struct dccp_opt_pend *opt, *next;
-
- list_for_each_entry_safe(opt, next, &dmsk->dccpms_pending,
- dccpop_node) {
- BUG_ON(opt->dccpop_val == NULL);
- kfree(opt->dccpop_val);
+ struct dccp_sock *dp = dccp_sk(sk);
+ struct list_head *fn = dreq ? &dreq->dreq_featneg : &dp->dccps_featneg;
+ bool server = false;
- if (opt->dccpop_sc != NULL) {
- BUG_ON(opt->dccpop_sc->dccpoc_val == NULL);
- kfree(opt->dccpop_sc->dccpoc_val);
- kfree(opt->dccpop_sc);
+ switch (sk->sk_state) {
+ /*
+ * Negotiation during connection setup
+ */
+ case DCCP_LISTEN:
+ server = true; /* fall through */
+ case DCCP_REQUESTING:
+ switch (opt) {
+ case DCCPO_CHANGE_L:
+ case DCCPO_CHANGE_R:
+ return dccp_feat_change_recv(fn, mandatory, opt, feat,
+ val, len, server);
+ case DCCPO_CONFIRM_R:
+ case DCCPO_CONFIRM_L:
+ return dccp_feat_confirm_recv(fn, mandatory, opt, feat,
+ val, len, server);
}
-
- kfree(opt);
- }
- INIT_LIST_HEAD(&dmsk->dccpms_pending);
-
- list_for_each_entry_safe(opt, next, &dmsk->dccpms_conf, dccpop_node) {
- BUG_ON(opt == NULL);
- if (opt->dccpop_val != NULL)
- kfree(opt->dccpop_val);
- kfree(opt);
}
- INIT_LIST_HEAD(&dmsk->dccpms_conf);
+ return 0; /* ignore FN options in all other states */
}
-EXPORT_SYMBOL_GPL(dccp_feat_clean);
-
-/* this is to be called only when a listening sock creates its child. It is
- * assumed by the function---the confirm is not duplicated, but rather it is
- * "passed on".
+/**
+ * dccp_feat_init - Seed feature negotiation with host-specific defaults
+ * This initialises global defaults, depending on the value of the sysctls.
+ * These can later be overridden by registering changes via setsockopt calls.
+ * The last link in the chain is finalise_settings, to make sure that between
+ * here and the start of actual feature negotiation no inconsistencies enter.
+ *
+ * All features not appearing below use either defaults or are otherwise
+ * later adjusted through dccp_feat_finalise_settings().
*/
-int dccp_feat_clone(struct sock *oldsk, struct sock *newsk)
+int dccp_feat_init(struct sock *sk)
{
- struct dccp_minisock *olddmsk = dccp_msk(oldsk);
- struct dccp_minisock *newdmsk = dccp_msk(newsk);
- struct dccp_opt_pend *opt;
- int rc = 0;
+ struct list_head *fn = &dccp_sk(sk)->dccps_featneg;
+ u8 on = 1, off = 0;
+ int rc;
+ struct {
+ u8 *val;
+ u8 len;
+ } tx, rx;
+
+ /* Non-negotiable (NN) features */
+ rc = __feat_register_nn(fn, DCCPF_SEQUENCE_WINDOW, 0,
+ sysctl_dccp_feat_sequence_window);
+ if (rc)
+ return rc;
- INIT_LIST_HEAD(&newdmsk->dccpms_pending);
- INIT_LIST_HEAD(&newdmsk->dccpms_conf);
+ /* Server-priority (SP) features */
- list_for_each_entry(opt, &olddmsk->dccpms_pending, dccpop_node) {
- struct dccp_opt_pend *newopt;
- /* copy the value of the option */
- u8 *val = kmemdup(opt->dccpop_val, opt->dccpop_len, GFP_ATOMIC);
+ /* Advertise that short seqnos are not supported (7.6.1) */
+ rc = __feat_register_sp(fn, DCCPF_SHORT_SEQNOS, true, true, &off, 1);
+ if (rc)
+ return rc;
- if (val == NULL)
- goto out_clean;
+ /* RFC 4340 12.1: "If a DCCP is not ECN capable, ..." */
+ rc = __feat_register_sp(fn, DCCPF_ECN_INCAPABLE, true, true, &on, 1);
+ if (rc)
+ return rc;
- newopt = kmemdup(opt, sizeof(*newopt), GFP_ATOMIC);
- if (newopt == NULL) {
- kfree(val);
- goto out_clean;
- }
+ /*
+ * We advertise the available list of CCIDs and reorder according to
+ * preferences, to avoid failure resulting from negotiating different
+ * singleton values (which always leads to failure).
+ * These settings can still (later) be overridden via sockopts.
+ */
+ if (ccid_get_builtin_ccids(&tx.val, &tx.len) ||
+ ccid_get_builtin_ccids(&rx.val, &rx.len))
+ return -ENOBUFS;
- /* insert the option */
- newopt->dccpop_val = val;
- list_add_tail(&newopt->dccpop_node, &newdmsk->dccpms_pending);
+ /* Pre-load all CCID modules that are going to be advertised */
+ rc = -EUNATCH;
+ if (ccid_request_modules(tx.val, tx.len))
+ goto free_ccid_lists;
- /* XXX what happens with backlogs and multiple connections at
- * once...
- */
- /* the master socket no longer needs to worry about confirms */
- opt->dccpop_sc = NULL; /* it's not a memleak---new socket has it */
+ if (!dccp_feat_prefer(sysctl_dccp_feat_tx_ccid, tx.val, tx.len) ||
+ !dccp_feat_prefer(sysctl_dccp_feat_rx_ccid, rx.val, rx.len))
+ goto free_ccid_lists;
- /* reset state for a new socket */
- opt->dccpop_conf = 0;
- }
+ rc = __feat_register_sp(fn, DCCPF_CCID, true, false, tx.val, tx.len);
+ if (rc)
+ goto free_ccid_lists;
- /* XXX not doing anything about the conf queue */
+ rc = __feat_register_sp(fn, DCCPF_CCID, false, false, rx.val, rx.len);
-out:
+free_ccid_lists:
+ kfree(tx.val);
+ kfree(rx.val);
return rc;
-
-out_clean:
- dccp_feat_clean(newdmsk);
- rc = -ENOMEM;
- goto out;
}
-EXPORT_SYMBOL_GPL(dccp_feat_clone);
-
-int dccp_feat_init(struct sock *sk)
+int dccp_feat_activate_values(struct sock *sk, struct list_head *fn_list)
{
struct dccp_sock *dp = dccp_sk(sk);
- struct dccp_minisock *dmsk = dccp_msk(sk);
- int rc;
+ struct dccp_feat_entry *cur, *next;
+ int idx;
+ dccp_feat_val *fvals[DCCP_FEAT_SUPPORTED_MAX][2] = {
+ [0 ... DCCP_FEAT_SUPPORTED_MAX-1] = { NULL, NULL }
+ };
- INIT_LIST_HEAD(&dmsk->dccpms_pending); /* XXX no longer used */
- INIT_LIST_HEAD(&dmsk->dccpms_conf); /* XXX no longer used */
+ list_for_each_entry(cur, fn_list, node) {
+ /*
+ * An empty Confirm means that either an unknown feature type
+ * or an invalid value was present. In the first case there is
+ * nothing to activate, in the other the default value is used.
+ */
+ if (cur->empty_confirm)
+ continue;
- /* CCID L */
- rc = __feat_register_sp(&dp->dccps_featneg, DCCPF_CCID, 1, 0,
- &dmsk->dccpms_tx_ccid, 1);
- if (rc)
- goto out;
+ idx = dccp_feat_index(cur->feat_num);
+ if (idx < 0) {
+ DCCP_BUG("Unknown feature %u", cur->feat_num);
+ goto activation_failed;
+ }
+ if (cur->state != FEAT_STABLE) {
+ DCCP_CRIT("Negotiation of %s %u failed in state %u",
+ cur->is_local ? "local" : "remote",
+ cur->feat_num, cur->state);
+ goto activation_failed;
+ }
+ fvals[idx][cur->is_local] = &cur->val;
+ }
- /* CCID R */
- rc = __feat_register_sp(&dp->dccps_featneg, DCCPF_CCID, 0, 0,
- &dmsk->dccpms_rx_ccid, 1);
- if (rc)
- goto out;
+ /*
+ * Activate in decreasing order of index, so that the CCIDs are always
+ * activated as the last feature. This avoids the case where a CCID
+ * relies on the initialisation of one or more features that it depends
+ * on (e.g. Send NDP Count, Send Ack Vector, and Ack Ratio features).
+ */
+ for (idx = DCCP_FEAT_SUPPORTED_MAX; --idx >= 0;)
+ if (__dccp_feat_activate(sk, idx, 0, fvals[idx][0]) ||
+ __dccp_feat_activate(sk, idx, 1, fvals[idx][1])) {
+ DCCP_CRIT("Could not activate %d", idx);
+ goto activation_failed;
+ }
- /* Ack ratio */
- rc = __feat_register_nn(&dp->dccps_featneg, DCCPF_ACK_RATIO, 0,
- dmsk->dccpms_ack_ratio);
-out:
- return rc;
-}
+ /* Clean up Change options which have been confirmed already */
+ list_for_each_entry_safe(cur, next, fn_list, node)
+ if (!cur->needs_confirm)
+ dccp_feat_list_pop(cur);
+
+ dccp_pr_debug("Activation OK\n");
+ return 0;
-EXPORT_SYMBOL_GPL(dccp_feat_init);
+activation_failed:
+ /*
+ * We clean up everything that may have been allocated, since
+ * it is difficult to track at which stage negotiation failed.
+ * This is ok, since all allocation functions below are robust
+ * against NULL arguments.
+ */
+ ccid_hc_rx_delete(dp->dccps_hc_rx_ccid, sk);
+ ccid_hc_tx_delete(dp->dccps_hc_tx_ccid, sk);
+ dp->dccps_hc_rx_ccid = dp->dccps_hc_tx_ccid = NULL;
+ dccp_ackvec_free(dp->dccps_hc_rx_ackvec);
+ dp->dccps_hc_rx_ackvec = NULL;
+ return -1;
+}
#ifdef CONFIG_IP_DCCP_DEBUG
const char *dccp_feat_typename(const u8 type)
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff