diff options
Diffstat (limited to 'net/dccp/feat.c')
| -rw-r--r-- | net/dccp/feat.c | 1225 |
1 files changed, 1163 insertions, 62 deletions
diff --git a/net/dccp/feat.c b/net/dccp/feat.c index 933a0ecf8d46..b127189550f1 100644 --- a/net/dccp/feat.c +++ b/net/dccp/feat.c @@ -6,6 +6,8 @@ * * ASSUMPTIONS * ----------- + * o Feature negotiation is coordinated with connection setup (as in TCP), wild + * changes of parameters of an established connection are not supported. * o All currently known SP features have 1-byte quantities. If in the future * extensions of RFCs 4340..42 define features with item lengths larger than * one byte, a feature-specific extension of the code will be required. @@ -23,53 +25,791 @@ #define DCCP_FEAT_SP_NOAGREE (-123) -int dccp_feat_change(struct dccp_minisock *dmsk, u8 type, u8 feature, - u8 *val, u8 len, gfp_t gfp) +/* + * 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_opt_pend *opt; + struct dccp_sock *dp = dccp_sk(sk); + struct ccid *new_ccid = ccid_new(ccid, sk, rx, gfp_any()); - dccp_feat_debug(type, feature, *val); + if (new_ccid == NULL) + return -ENOMEM; - if (len > 3) { - DCCP_WARN("invalid length %d\n", len); - return -EINVAL; + 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; } - /* XXX add further sanity checks */ + return 0; +} - /* 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; +static int dccp_hdlr_seq_win(struct sock *sk, u64 seq_win, bool rx) +{ + if (!rx) + dccp_msk(sk)->dccpms_sequence_window = seq_win; + 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_msk(sk)->dccpms_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) + * +--------------------------+----+-----+----+----+---------+-----------+ + * | Feature | Location | Reconc. | Initial | Section | + * | | RX | TX | SP | NN | Value | Reference | + * +--------------------------+----+-----+----+----+---------+-----------+ + * | DCCPF_CCID | | X | X | | 2 | 10 | + * | DCCPF_SHORT_SEQNOS | | X | X | | 0 | 7.6.1 | + * | DCCPF_SEQUENCE_WINDOW | | X | | X | 100 | 7.5.2 | + * | DCCPF_ECN_INCAPABLE | X | | X | | 0 | 12.1 | + * | DCCPF_ACK_RATIO | | X | | X | 2 | 11.3 | + * | DCCPF_SEND_ACK_VECTOR | X | | X | | 0 | 11.5 | + * | DCCPF_SEND_NDP_COUNT | | X | X | | 0 | 7.7.2 | + * | DCCPF_MIN_CSUM_COVER | X | | X | | 0 | 9.2.1 | + * | DCCPF_DATA_CHECKSUM | X | | X | | 0 | 9.3.1 | + * | DCCPF_SEND_LEV_RATE | X | | X | | 0 | 4342/8.4 | + * +--------------------------+----+-----+----+----+---------+-----------+ + */ +} dccp_feat_table[] = { + { 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) + +/** + * dccp_feat_index - Hash function to map feature number into array position + * Returns consecutive array index or -1 if the feature is not understood. + */ +static int dccp_feat_index(u8 feat_num) +{ + /* The first 9 entries are occupied by the types from RFC 4340, 6.4 */ + if (feat_num > DCCPF_RESERVED && feat_num <= DCCPF_DATA_CHECKSUM) + return feat_num - 1; + + /* + * Other features: add cases for new feature types here after adding + * them to the above table. + */ + switch (feat_num) { + case DCCPF_SEND_LEV_RATE: + return DCCP_FEAT_SUPPORTED_MAX - 1; + } + return -1; +} + +static u8 dccp_feat_type(u8 feat_num) +{ + int idx = dccp_feat_index(feat_num); + + if (idx < 0) + return FEAT_UNKNOWN; + return dccp_feat_table[idx].reconciliation; +} + +static int dccp_feat_default_value(u8 feat_num) +{ + int idx = dccp_feat_index(feat_num); + /* + * There are no default values for unknown features, so encountering a + * negative index here indicates a serious problem somewhere else. + */ + DCCP_BUG_ON(idx < 0); + + return idx < 0 ? 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) +{ + fval->sp.len = len; + if (fval->sp.len > 0) { + fval->sp.vec = kmemdup(val, len, gfp_any()); + if (fval->sp.vec == NULL) { + fval->sp.len = 0; + return -ENOBUFS; + } + } + return 0; +} + +static void dccp_feat_val_destructor(u8 feat_num, dccp_feat_val *val) +{ + if (unlikely(val == NULL)) + return; + if (dccp_feat_type(feat_num) == FEAT_SP) + kfree(val->sp.vec); + memset(val, 0, sizeof(*val)); +} + +static struct dccp_feat_entry * + dccp_feat_clone_entry(struct dccp_feat_entry const *original) +{ + struct dccp_feat_entry *new; + u8 type = dccp_feat_type(original->feat_num); + + if (type == FEAT_UNKNOWN) + return NULL; + + new = kmemdup(original, sizeof(struct dccp_feat_entry), gfp_any()); + if (new == NULL) + return NULL; + + if (type == FEAT_SP && dccp_feat_clone_sp_val(&new->val, + original->val.sp.vec, + original->val.sp.len)) { + kfree(new); + return NULL; + } + return new; +} + +static void dccp_feat_entry_destructor(struct dccp_feat_entry *entry) +{ + if (entry != NULL) { + dccp_feat_val_destructor(entry->feat_num, &entry->val); + kfree(entry); + } +} + +/* + * List management functions + * + * Feature negotiation lists rely on and maintain the following invariants: + * - each feat_num in the list is known, i.e. we know its type and default value + * - each feat_num/is_local combination is unique (old entries are overwritten) + * - SP values are always freshly allocated + * - list is sorted in increasing order of feature number (faster lookup) + */ +static struct dccp_feat_entry *dccp_feat_list_lookup(struct list_head *fn_list, + u8 feat_num, bool is_local) +{ + struct dccp_feat_entry *entry; + + list_for_each_entry(entry, fn_list, node) { + if (entry->feat_num == feat_num && entry->is_local == is_local) + return entry; + else if (entry->feat_num > feat_num) + break; + } + return NULL; +} + +/** + * dccp_feat_entry_new - Central list update routine (called by all others) + * @head: list to add to + * @feat: feature number + * @local: whether the local (1) or remote feature with number @feat is meant + * This is the only constructor and serves to ensure the above invariants. + */ +static struct dccp_feat_entry * + dccp_feat_entry_new(struct list_head *head, u8 feat, bool local) +{ + struct dccp_feat_entry *entry; + + list_for_each_entry(entry, head, node) + if (entry->feat_num == feat && entry->is_local == local) { + dccp_feat_val_destructor(entry->feat_num, &entry->val); + return entry; + } else if (entry->feat_num > feat) { + head = &entry->node; + break; + } + + entry = kmalloc(sizeof(*entry), gfp_any()); + if (entry != NULL) { + entry->feat_num = feat; + entry->is_local = local; + list_add_tail(&entry->node, head); + } + return entry; +} + +/** + * dccp_feat_push_change - Add/overwrite a Change option in the list + * @fn_list: feature-negotiation list to update + * @feat: one of %dccp_feature_numbers + * @local: whether local (1) or remote (0) @feat_num is meant + * @needs_mandatory: whether to use Mandatory feature negotiation options + * @fval: pointer to NN/SP value to be inserted (will be copied) + */ +static int dccp_feat_push_change(struct list_head *fn_list, u8 feat, u8 local, + u8 mandatory, dccp_feat_val *fval) +{ + struct dccp_feat_entry *new = dccp_feat_entry_new(fn_list, feat, local); + + if (new == NULL) + return -ENOMEM; + + new->feat_num = feat; + new->is_local = local; + new->state = FEAT_INITIALISING; + new->needs_confirm = 0; + new->empty_confirm = 0; + new->val = *fval; + new->needs_mandatory = mandatory; + + return 0; +} + +/** + * dccp_feat_push_confirm - Add a Confirm entry to the FN list + * @fn_list: feature-negotiation list to add to + * @feat: one of %dccp_feature_numbers + * @local: whether local (1) or remote (0) @feat_num is being confirmed + * @fval: pointer to NN/SP value to be inserted or NULL + * Returns 0 on success, a Reset code for further processing otherwise. + */ +static int dccp_feat_push_confirm(struct list_head *fn_list, u8 feat, u8 local, + dccp_feat_val *fval) +{ + struct dccp_feat_entry *new = dccp_feat_entry_new(fn_list, feat, local); + + if (new == NULL) + return DCCP_RESET_CODE_TOO_BUSY; + + new->feat_num = feat; + new->is_local = local; + new->state = FEAT_STABLE; /* transition in 6.6.2 */ + new->needs_confirm = 1; + new->empty_confirm = (fval == NULL); + new->val.nn = 0; /* zeroes the whole structure */ + if (!new->empty_confirm) + new->val = *fval; + new->needs_mandatory = 0; + + return 0; +} + +static int dccp_push_empty_confirm(struct list_head *fn_list, u8 feat, u8 local) +{ + return dccp_feat_push_confirm(fn_list, feat, local, NULL); +} + +static inline void dccp_feat_list_pop(struct dccp_feat_entry *entry) +{ + list_del(&entry->node); + dccp_feat_entry_destructor(entry); +} + +void dccp_feat_list_purge(struct list_head *fn_list) +{ + struct dccp_feat_entry *entry, *next; + + list_for_each_entry_safe(entry, next, fn_list, node) + dccp_feat_entry_destructor(entry); + INIT_LIST_HEAD(fn_list); +} +EXPORT_SYMBOL_GPL(dccp_feat_list_purge); + +/* generate @to as full clone of @from - @to must not contain any nodes */ +int dccp_feat_clone_list(struct list_head const *from, struct list_head *to) +{ + struct dccp_feat_entry *entry, *new; + + INIT_LIST_HEAD(to); + list_for_each_entry(entry, from, node) { + new = dccp_feat_clone_entry(entry); + if (new == NULL) + goto cloning_failed; + list_add_tail(&new->node, to); + } + return 0; + +cloning_failed: + dccp_feat_list_purge(to); + 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) { + case DCCPF_ACK_RATIO: + return val <= DCCPF_ACK_RATIO_MAX; + case DCCPF_SEQUENCE_WINDOW: + return val >= DCCPF_SEQ_WMIN && val <= DCCPF_SEQ_WMAX; + } + return 0; /* feature unknown - so we can't tell */ +} + +/* check that SP values are within the ranges defined in RFC 4340 */ +static u8 dccp_feat_is_valid_sp_val(u8 feat_num, u8 val) +{ + switch (feat_num) { + case DCCPF_CCID: + return val == DCCPC_CCID2 || val == DCCPC_CCID3; + /* Type-check Boolean feature values: */ + case DCCPF_SHORT_SEQNOS: + case DCCPF_ECN_INCAPABLE: + case DCCPF_SEND_ACK_VECTOR: + case DCCPF_SEND_NDP_COUNT: + case DCCPF_DATA_CHECKSUM: + case DCCPF_SEND_LEV_RATE: + return val < 2; + case DCCPF_MIN_CSUM_COVER: + return val < 16; + } + return 0; /* feature unknown */ +} + +static u8 dccp_feat_sp_list_ok(u8 feat_num, u8 const *sp_list, u8 sp_len) +{ + if (sp_list == NULL || sp_len < 1) + return 0; + while (sp_len--) + if (!dccp_feat_is_valid_sp_val(feat_num, *sp_list++)) return 0; + return 1; +} + +/** + * 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; +} - /* negotiation for a new feature */ - opt = kmalloc(sizeof(*opt), gfp); - if (opt == NULL) +/** + * __feat_register_nn - Register new NN value on socket + * @fn: feature-negotiation list to register with + * @feat: an NN feature from %dccp_feature_numbers + * @mandatory: use Mandatory option if 1 + * @nn_val: value to register (restricted to 4 bytes) + * Note that NN features are local by definition (RFC 4340, 6.3.2). + */ +static int __feat_register_nn(struct list_head *fn, u8 feat, + u8 mandatory, u64 nn_val) +{ + dccp_feat_val fval = { .nn = nn_val }; + + if (dccp_feat_type(feat) != FEAT_NN || + !dccp_feat_is_valid_nn_val(feat, nn_val)) + return -EINVAL; + + /* Don't bother with default values, they will be activated anyway. */ + if (nn_val - (u64)dccp_feat_default_value(feat) == 0) + return 0; + + return dccp_feat_push_change(fn, feat, 1, mandatory, &fval); +} + +/** + * __feat_register_sp - Register new SP value/list on socket + * @fn: feature-negotiation list to register with + * @feat: an SP feature from %dccp_feature_numbers + * @is_local: whether the local (1) or the remote (0) @feat is meant + * @mandatory: use Mandatory option if 1 + * @sp_val: SP value followed by optional preference list + * @sp_len: length of @sp_val in bytes + */ +static int __feat_register_sp(struct list_head *fn, u8 feat, u8 is_local, + u8 mandatory, u8 const *sp_val, u8 sp_len) +{ + dccp_feat_val fval; + + if (dccp_feat_type(feat) != FEAT_SP || + !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; - opt->dccpop_type = type; - opt->dccpop_feat = feature; - opt->dccpop_len = len; - opt->dccpop_val = val; - opt->dccpop_conf = 0; - opt->dccpop_sc = NULL; + return dccp_feat_push_change(fn, feat, is_local, mandatory, &fval); +} + +/** + * 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; + return __feat_register_sp(&dccp_sk(sk)->dccps_featneg, feat, is_local, + 0, list, len); +} + +/* Analogous to dccp_feat_register_sp(), but for non-negotiable values */ +int dccp_feat_register_nn(struct sock *sk, u8 feat, u64 val) +{ + /* 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); +} + +/* + * 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) +{ + 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: + return NULL; + } +} + +/** + * 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) +{ + 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(opt->dccpop_val == 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 }; - list_add_tail(&opt->dccpop_node, &dmsk->dccpms_pending); + /* + * 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. + */ + 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; } -EXPORT_SYMBOL_GPL(dccp_feat_change); +/** + * 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; + + for (is_local = 0; is_local <= 1; is_local++) { + entry = dccp_feat_list_lookup(fn, DCCPF_CCID, is_local); + + if (entry != NULL && !entry->empty_confirm) + ccid = entry->val.sp.vec[0]; + else + ccid = dccp_feat_default_value(DCCPF_CCID); + + if (dccp_feat_propagate_ccid(fn, ccid, is_local)) + return -1; + } + return 0; +} static int dccp_feat_update_ccid(struct sock *sk, u8 type, u8 new_ccid_nr) { @@ -116,6 +856,76 @@ static int dccp_feat_update(struct sock *sk, u8 type, u8 feat, u8 val) return 0; } +/* 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) +{ + u8 c, s; + + for (s = 0; s < slen; s++) + for (c = 0; c < clen; c++) + if (servlist[s] == clilist[c]) + return servlist[s]; + return -1; +} + +/** + * 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; + + 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; + } + return does_occur; +} + +/** + * 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) +{ + int rc; + + if (!fv->sp.vec || !arr) { + DCCP_CRIT("NULL feature value or array"); + return 0; + } + + 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); + + if (!reorder) + return rc; + if (rc < 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); +} + +#ifdef __this_is_the_old_framework_and_will_be_removed_later_in_a_subsequent_patch static int dccp_feat_reconcile(struct sock *sk, struct dccp_opt_pend *opt, u8 *rpref, u8 rlen) { @@ -377,18 +1187,23 @@ int dccp_feat_change_recv(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len) { int rc; + /* Ignore Change requests other than during connection setup */ + if (sk->sk_state != DCCP_LISTEN && sk->sk_state != DCCP_REQUESTING) + 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); + /* XXX Obsoleted by next patch + 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); + /* XXX Obsoleted by next patch + rc = dccp_feat_nn(sk, type, feature, val, len); */ break; /* XXX implement other features */ @@ -426,6 +1241,9 @@ int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature, int found = 0; int all_confirmed = 1; + /* Ignore Confirm options other than during connection setup */ + if (sk->sk_state != DCCP_LISTEN && sk->sk_state != DCCP_REQUESTING) + return 0; dccp_feat_debug(type, feature, *val); /* locate our change request */ @@ -460,17 +1278,6 @@ int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature, all_confirmed = 0; } - /* fix re-transmit timer */ - /* XXX gotta make sure that no option negotiation occurs during - * connection shutdown. Consider that the CLOSEREQ is sent and timer is - * on. if all options are confirmed it might kill timer which should - * remain alive until close is received. - */ - if (all_confirmed) { - dccp_pr_debug("clear feat negotiation timer %p\n", sk); - inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS); - } - if (!found) dccp_pr_debug("%s(%d, ...) never requested\n", dccp_feat_typename(type), feature); @@ -478,6 +1285,7 @@ int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature, } EXPORT_SYMBOL_GPL(dccp_feat_confirm_recv); +#endif /* (later) */ void dccp_feat_clean(struct dccp_minisock *dmsk) { @@ -564,48 +1372,339 @@ out_clean: EXPORT_SYMBOL_GPL(dccp_feat_clone); -static int __dccp_feat_init(struct dccp_minisock *dmsk, u8 type, u8 feat, - u8 *val, u8 len) +/** + * 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) { - int rc = -ENOMEM; - u8 *copy = kmemdup(val, len, GFP_KERNEL); + u8 defval, type = dccp_feat_type(feat); + const bool local = (opt == DCCPO_CHANGE_R); + struct dccp_feat_entry *entry; + dccp_feat_val fval; + + if (len == 0 || type == FEAT_UNKNOWN) /* 6.1 and 6.6.8 */ + goto unknown_feature_or_value; + + /* + * 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; + + /* 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; - if (copy != NULL) { - rc = dccp_feat_change(dmsk, type, feat, copy, len, GFP_KERNEL); - if (rc) - kfree(copy); + return dccp_feat_push_confirm(fn, feat, local, &fval); } - return rc; + + /* + * 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; + } + + /* 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; + } + + return dccp_feat_push_confirm(fn, feat, local, &fval); + + } else if (entry->state == FEAT_UNSTABLE) { /* 6.6.2 */ + return 0; + } + + 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. + */ + 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; + +unknown_feature_or_value: + if (!is_mandatory) + return dccp_push_empty_confirm(fn, feat, local); + +not_valid_or_not_known: + return is_mandatory ? DCCP_RESET_CODE_MANDATORY_ERROR + : DCCP_RESET_CODE_OPTION_ERROR; } -int dccp_feat_init(struct dccp_minisock *dmsk) +/** + * 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 *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; + + if (!local && type == FEAT_NN) /* 6.3.2 */ + goto confirmation_failed; + return 0; + } + + 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; + } + + if (type == FEAT_NN) { + if (len > sizeof(entry->val.nn)) + goto confirmation_failed; + + if (entry->val.nn == dccp_decode_value_var(val, len)) + goto confirmation_succeeded; + + DCCP_WARN("Bogus Confirm for non-existing value\n"); + goto confirmation_failed; + } + + /* + * 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; + } + + /* 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; + +confirmation_succeeded: + entry->state = FEAT_STABLE; + return 0; + +confirmation_failed: + DCCP_WARN("Confirmation failed\n"); + return is_mandatory ? DCCP_RESET_CODE_MANDATORY_ERROR + : DCCP_RESET_CODE_OPTION_ERROR; +} + +/** + * 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_sock *dp = dccp_sk(sk); + struct list_head *fn = dreq ? &dreq->dreq_featneg : &dp->dccps_featneg; + bool server = false; + + 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); + } + } + return 0; /* ignore FN options in all other states */ +} + +int dccp_feat_init(struct sock *sk) +{ + struct dccp_sock *dp = dccp_sk(sk); + struct dccp_minisock *dmsk = dccp_msk(sk); int rc; - INIT_LIST_HEAD(&dmsk->dccpms_pending); - INIT_LIST_HEAD(&dmsk->dccpms_conf); + INIT_LIST_HEAD(&dmsk->dccpms_pending); /* XXX no longer used */ + INIT_LIST_HEAD(&dmsk->dccpms_conf); /* XXX no longer used */ /* CCID L */ - rc = __dccp_feat_init(dmsk, DCCPO_CHANGE_L, DCCPF_CCID, - &dmsk->dccpms_tx_ccid, 1); + rc = __feat_register_sp(&dp->dccps_featneg, DCCPF_CCID, 1, 0, + &dmsk->dccpms_tx_ccid, 1); if (rc) goto out; /* CCID R */ - rc = __dccp_feat_init(dmsk, DCCPO_CHANGE_R, DCCPF_CCID, - &dmsk->dccpms_rx_ccid, 1); + rc = __feat_register_sp(&dp->dccps_featneg, DCCPF_CCID, 0, 0, + &dmsk->dccpms_rx_ccid, 1); if (rc) goto out; /* Ack ratio */ - rc = __dccp_feat_init(dmsk, DCCPO_CHANGE_L, DCCPF_ACK_RATIO, - &dmsk->dccpms_ack_ratio, 1); + rc = __feat_register_nn(&dp->dccps_featneg, DCCPF_ACK_RATIO, 0, + dp->dccps_l_ack_ratio); out: return rc; } EXPORT_SYMBOL_GPL(dccp_feat_init); +int dccp_feat_activate_values(struct sock *sk, struct list_head *fn_list) +{ + struct dccp_sock *dp = dccp_sk(sk); + 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 } + }; + + 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; + + 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; + } + + /* + * 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; + } + + /* 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; + +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) { @@ -639,6 +1738,8 @@ const char *dccp_feat_name(const u8 feat) if (feat > DCCPF_DATA_CHECKSUM && feat < DCCPF_MIN_CCID_SPECIFIC) return feature_names[DCCPF_RESERVED]; + if (feat == DCCPF_SEND_LEV_RATE) + return "Send Loss Event Rate"; if (feat >= DCCPF_MIN_CCID_SPECIFIC) return "CCID-specific"; |
