diff options
Diffstat (limited to 'net/dccp/feat.c')
| -rw-r--r-- | net/dccp/feat.c | 1458 |
1 files changed, 1027 insertions, 431 deletions
diff --git a/net/dccp/feat.c b/net/dccp/feat.c index 933a0ecf8d4..30f9fb76b92 100644 --- a/net/dccp/feat.c +++ b/net/dccp/feat.c @@ -1,11 +1,17 @@ /* * 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 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 * ----------- + * 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. @@ -15,597 +21,1185 @@ * 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) - -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); - 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; -} - -EXPORT_SYMBOL_GPL(dccp_feat_change); - -static int dccp_feat_update_ccid(struct sock *sk, u8 type, u8 new_ccid_nr) +/* + * 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 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; + struct ccid *new_ccid = ccid_new(ccid, sk, rx, gfp_any()); - /* 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_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_feat_update(struct sock *sk, u8 type, u8 feat, u8 val) +static int dccp_hdlr_ack_ratio(struct sock *sk, u64 ratio, bool rx) { - dccp_feat_debug(type, feat, val); + if (rx) + dccp_sk(sk)->dccps_r_ack_ratio = ratio; + else + dccp_sk(sk)->dccps_l_ack_ratio = ratio; + return 0; +} - 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; +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_feat_reconcile(struct sock *sk, struct dccp_opt_pend *opt, - u8 *rpref, u8 rlen) +static int dccp_hdlr_ndp(struct sock *sk, u64 enable, bool rx) { - struct dccp_sock *dp = dccp_sk(sk); - u8 *spref, slen, *res = NULL; - int i, j, rc, agree = 1; + if (!rx) + dccp_sk(sk)->dccps_send_ndp_count = (enable > 0); + return 0; +} - BUG_ON(rpref == NULL); +/* + * 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); - /* 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; + 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); } - /* - * Now we have server preference list in spref and client preference in - * rpref - */ - BUG_ON(spref == NULL); - BUG_ON(rpref == NULL); + return 0; +} - /* FIXME sanity check vals */ +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; - /* 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; + /* + * 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; +} - /* 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; +static u8 dccp_feat_type(u8 feat_num) +{ + int idx = dccp_feat_index(feat_num); - default: - DCCP_BUG("Fell through, feat=%d", opt->dccpop_feat); - /* XXX implement res */ - return -EFAULT; - } + if (idx < 0) + return FEAT_UNKNOWN; + return dccp_feat_table[idx].reconciliation; +} - dccp_pr_debug("Don't agree... reconfirming %d\n", *res); - agree = 0; /* this is used for mandatory options... */ - } +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); - /* need to put result and our preference list */ - rlen = 1 + opt->dccpop_len; - rpref = kmalloc(rlen, GFP_ATOMIC); - if (rpref == NULL) - return -ENOMEM; + return idx < 0 ? 0 : dccp_feat_table[idx].default_value; +} - *rpref = *res; - memcpy(&rpref[1], opt->dccpop_val, opt->dccpop_len); +static int __dccp_feat_activate(struct sock *sk, const int idx, + const bool is_local, dccp_feat_val const *fval) +{ + bool rx; + u64 val; - /* 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; + 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 { - /* 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"); + val = fval->nn; } - memset(opt->dccpop_sc, 0, sizeof(*opt->dccpop_sc)); - opt->dccpop_sc->dccpoc_val = rpref; - opt->dccpop_sc->dccpoc_len = rlen; + /* Location is RX if this is a local-RX or remote-TX feature */ + rx = (is_local == (dccp_feat_table[idx].rxtx == FEAT_AT_RX)); - /* 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; - } + return dccp_feat_table[idx].activation_hdlr(sk, val, rx); +} - dccp_pr_debug("Will confirm %d\n", *rpref); +/* 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; +} - /* 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"); +/* 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; +} - return agree ? 0 : DCCP_FEAT_SP_NOAGREE; /* used for mandatory opts */ +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 int dccp_feat_sp(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len) +static struct dccp_feat_entry * + dccp_feat_clone_entry(struct dccp_feat_entry const *original) { - struct dccp_minisock *dmsk = dccp_msk(sk); - struct dccp_opt_pend *opt; - int rc = 1; - u8 t; + struct dccp_feat_entry *new; + u8 type = dccp_feat_type(original->feat_num); - /* - * 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; + if (type == FEAT_UNKNOWN) + return NULL; - /* 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; + new = kmemdup(original, sizeof(struct dccp_feat_entry), gfp_any()); + if (new == NULL) + return NULL; - /* find the winner from the two preference lists */ - rc = dccp_feat_reconcile(sk, opt, val, len); - break; + 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; +} - /* 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); +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); + } +} - return rc; +/* + * 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; } -static int dccp_feat_nn(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len) +/** + * 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_opt_pend *opt; - struct dccp_minisock *dmsk = dccp_msk(sk); - u8 *copy; - int rc; + 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; + } - /* 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; + 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; +} - /* XXX sanity check opt val */ +/** + * 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); - /* copy option so we can confirm it */ - opt = kzalloc(sizeof(*opt), GFP_ATOMIC); - if (opt == NULL) + if (new == NULL) return -ENOMEM; - copy = kmemdup(val, len, GFP_ATOMIC); - if (copy == NULL) { - kfree(opt); - 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; - opt->dccpop_type = DCCPO_CONFIRM_R; /* NN can only confirm R */ - opt->dccpop_feat = feature; - opt->dccpop_val = copy; - opt->dccpop_len = len; + return 0; +} - /* change feature */ - rc = dccp_feat_update(sk, type, feature, *val); - if (rc) { - kfree(opt->dccpop_val); - kfree(opt); - return rc; - } +/** + * 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); - dccp_feat_debug(type, feature, *copy); + if (new == NULL) + return DCCP_RESET_CODE_TOO_BUSY; - list_add_tail(&opt->dccpop_node, &dmsk->dccpms_conf); + 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 void dccp_feat_empty_confirm(struct dccp_minisock *dmsk, - u8 type, u8 feature) +static int dccp_push_empty_confirm(struct list_head *fn_list, u8 feat, u8 local) { - /* XXX check if other confirms for that are queued and recycle slot */ - struct dccp_opt_pend *opt = kzalloc(sizeof(*opt), GFP_ATOMIC); + return dccp_feat_push_confirm(fn_list, feat, local, NULL); +} - if (opt == NULL) { - /* XXX what do we do? Ignoring should be fine. It's a change - * after all =P - */ - return; - } +static inline void dccp_feat_list_pop(struct dccp_feat_entry *entry) +{ + list_del(&entry->node); + dccp_feat_entry_destructor(entry); +} - 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; +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); } - opt->dccpop_feat = feature; - opt->dccpop_val = NULL; - opt->dccpop_len = 0; + return 0; + +cloning_failed: + dccp_feat_list_purge(to); + return -ENOMEM; +} - /* change feature */ - dccp_pr_debug("Empty %s(%d)\n", dccp_feat_typename(type), feature); +/** + * 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; +} - list_add_tail(&opt->dccpop_node, &dmsk->dccpms_conf); +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 */ } -static void dccp_feat_flush_confirm(struct sock *sk) +/* 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) { - 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); + 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 */ +} - if (!yes) { - struct dccp_opt_pend *opt; +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; +} - list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) { - if (opt->dccpop_conf) { - yes = 1; - break; +/** + * 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; +} - if (!yes) - return; +/** + * __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 }; - /* 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); + 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); } -int dccp_feat_change_recv(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len) +/** + * __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) { - int rc; + dccp_feat_val fval; - dccp_feat_debug(type, feature, *val); + if (dccp_feat_type(feat) != FEAT_SP || + !dccp_feat_sp_list_ok(feat, sp_val, sp_len)) + return -EINVAL; - /* 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; + /* Avoid negotiating alien CCIDs by only advertising supported ones */ + if (feat == DCCPF_CCID && !ccid_support_check(sp_val, sp_len)) + return -EOPNOTSUPP; - /* deal with NN features */ - case DCCPF_ACK_RATIO: - rc = dccp_feat_nn(sk, type, feature, val, len); - break; + if (dccp_feat_clone_sp_val(&fval, sp_val, sp_len)) + return -ENOMEM; - /* XXX implement other features */ - default: - dccp_pr_debug("UNIMPLEMENTED: not handling %s(%d, ...)\n", - dccp_feat_typename(type), feature); - rc = -EFAULT; - break; - } + return dccp_feat_push_change(fn, feat, is_local, mandatory, &fval); +} - /* 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 +/** + * 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. */ - if (rc != DCCP_FEAT_SP_NOAGREE) - dccp_feat_empty_confirm(dccp_msk(sk), type, feature); + { /* 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; } +} - /* generate the confirm [if required] */ - dccp_feat_flush_confirm(sk); - +/** + * 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; } -EXPORT_SYMBOL_GPL(dccp_feat_change_recv); +/** + * 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 }; -int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature, - u8 *val, u8 len) + /* + * 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) { - u8 t; - struct dccp_opt_pend *opt; - struct dccp_minisock *dmsk = dccp_msk(sk); - int found = 0; - int all_confirmed = 1; + struct list_head *fn = &dreq->dreq_featneg; + struct dccp_feat_entry *entry; + u8 is_local, ccid; - dccp_feat_debug(type, feature, *val); + for (is_ |