/* * net/dccp/feat.c * * An implementation of the DCCP protocol * Andrea Bittau <a.bittau@cs.ucl.ac.uk> * * 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. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * 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) 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 */ /* * 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 }, { 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 }, }; #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; } /* 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; } 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; } 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; } /** * __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; 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; } /** * 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 }; /* * 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; } /** * 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) { 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; } static int dccp_feat_update(struct sock *sk, u8 type, u8 feat, u8 val) { dccp_feat_debug(type, feat, val); switch (feat) { case DCCPF_CCID: return dccp_feat_update_ccid(sk, type, val); default: dccp_pr_debug("UNIMPLEMENTED: %s(%d, ...)\n", dccp_feat_typename(type), feat); break; } return 0; } static int dccp_feat_reconcile(struct sock *sk, struct dccp_opt_pend *opt, u8 *rpref, u8 rlen) { struct dccp_sock *dp = dccp_sk(sk); u8 *spref, slen, *res = NULL; int i, j, rc, agree = 1; BUG_ON(rpref == NULL); /* 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 */ 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)); opt->dccpop_sc->dccpoc_val = rpref; opt->dccpop_sc->dccpoc_len = rlen; /* 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; } dccp_pr_debug("Will confirm %d\n", *rpref); /* 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"); } return agree ? 0 : DCCP_FEAT_SP_NOAGREE; /* used for mandatory opts */ } static int dccp_feat_sp(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len) { struct dccp_minisock *dmsk = dccp_msk(sk); struct dccp_opt_pend *opt; int rc = 1; u8 t; /* * 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; /* 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; /* find the winner from the two preference lists */ rc = dccp_feat_reconcile(sk, opt, val, len); break; } /* 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; } static int dccp_feat_nn(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len) { 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; } opt->dccpop_type = DCCPO_CONFIRM_R; /* NN can only confirm R */ opt->dccpop_feat = feature; opt->dccpop_val = copy; opt->dccpop_len = len; /* change feature */ rc = dccp_feat_update(sk, type, feature, *val); if (rc) { kfree(opt->dccpop_val); kfree(opt); return rc; } dccp_feat_debug(type, feature, *copy); list_add_tail(&opt->dccpop_node, &dmsk->dccpms_conf); return 0; } static void dccp_feat_empty_confirm(struct dccp_minisock *dmsk, u8 type, u8 feature) { /* 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); list_add_tail(&opt->dccpop_node, &dmsk->dccpms_conf); } 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); if (!yes) { struct dccp_opt_pend *opt; list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) { if (opt->dccpop_conf) { yes = 1; break; } } } if (!yes) return; /* 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); } 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); 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 (rc != DCCP_FEAT_SP_NOAGREE) dccp_feat_empty_confirm(dccp_msk(sk), type, feature); } /* generate the confirm [if required] */ dccp_feat_flush_confirm(sk); return rc; } EXPORT_SYMBOL_GPL(dccp_feat_change_recv); int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len) { u8 t; struct dccp_opt_pend *opt; struct dccp_minisock *dmsk = dccp_msk(sk); 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 */ 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; } /* 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 */ opt->dccpop_conf = 1; /* We got a confirmation---change the option */ dccp_feat_update(sk, opt->dccpop_type, opt->dccpop_feat, *val); /* XXX check the return value of dccp_feat_update */ break; } if (!opt->dccpop_conf) all_confirmed = 0; } if (!found) dccp_pr_debug("%s(%d, ...) never requested\n", dccp_feat_typename(type), feature); return 0; } EXPORT_SYMBOL_GPL(dccp_feat_confirm_recv); void dccp_feat_clean(struct dccp_minisock *dmsk) { 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); if (opt->dccpop_sc != NULL) { BUG_ON(opt->dccpop_sc->dccpoc_val == NULL); kfree(opt->dccpop_sc->dccpoc_val); kfree(opt->dccpop_sc); } 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); } 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". */ int dccp_feat_clone(struct sock *oldsk, struct sock *newsk) { struct dccp_minisock *olddmsk = dccp_msk(oldsk); struct dccp_minisock *newdmsk = dccp_msk(newsk); struct dccp_opt_pend *opt; int rc = 0; INIT_LIST_HEAD(&newdmsk->dccpms_pending); INIT_LIST_HEAD(&newdmsk->dccpms_conf); 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); if (val == NULL) goto out_clean; newopt = kmemdup(opt, sizeof(*newopt), GFP_ATOMIC); if (newopt == NULL) { kfree(val); goto out_clean; } /* insert the option */ newopt->dccpop_val = val; list_add_tail(&newopt->dccpop_node, &newdmsk->dccpms_pending); /* 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 */ /* reset state for a new socket */ opt->dccpop_conf = 0; } /* XXX not doing anything about the conf queue */ out: 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) { struct dccp_sock *dp = dccp_sk(sk); struct dccp_minisock *dmsk = dccp_msk(sk); int rc; INIT_LIST_HEAD(&dmsk->dccpms_pending); /* XXX no longer used */ INIT_LIST_HEAD(&dmsk->dccpms_conf); /* XXX no longer used */ /* CCID L */ rc = __feat_register_sp(&dp->dccps_featneg, DCCPF_CCID, 1, 0, &dmsk->dccpms_tx_ccid, 1); if (rc) goto out; /* CCID R */ rc = __feat_register_sp(&dp->dccps_featneg, DCCPF_CCID, 0, 0, &dmsk->dccpms_rx_ccid, 1); if (rc) goto out; /* Ack ratio */ 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); #ifdef CONFIG_IP_DCCP_DEBUG const char *dccp_feat_typename(const u8 type) { switch(type) { case DCCPO_CHANGE_L: return("ChangeL"); case DCCPO_CONFIRM_L: return("ConfirmL"); case DCCPO_CHANGE_R: return("ChangeR"); case DCCPO_CONFIRM_R: return("ConfirmR"); /* the following case must not appear in feature negotation */ default: dccp_pr_debug("unknown type %d [BUG!]\n", type); } return NULL; } EXPORT_SYMBOL_GPL(dccp_feat_typename); const char *dccp_feat_name(const u8 feat) { static const char *feature_names[] = { [DCCPF_RESERVED] = "Reserved", [DCCPF_CCID] = "CCID", [DCCPF_SHORT_SEQNOS] = "Allow Short Seqnos", [DCCPF_SEQUENCE_WINDOW] = "Sequence Window", [DCCPF_ECN_INCAPABLE] = "ECN Incapable", [DCCPF_ACK_RATIO] = "Ack Ratio", [DCCPF_SEND_ACK_VECTOR] = "Send ACK Vector", [DCCPF_SEND_NDP_COUNT] = "Send NDP Count", [DCCPF_MIN_CSUM_COVER] = "Min. Csum Coverage", [DCCPF_DATA_CHECKSUM] = "Send Data Checksum", }; 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"; return feature_names[feat]; } EXPORT_SYMBOL_GPL(dccp_feat_name); #endif /* CONFIG_IP_DCCP_DEBUG */