diff options
Diffstat (limited to 'net/dccp/feat.c')
| -rw-r--r-- | net/dccp/feat.c | 1581 |
1 files changed, 0 insertions, 1581 deletions
diff --git a/net/dccp/feat.c b/net/dccp/feat.c deleted file mode 100644 index f7554dcdaaba..000000000000 --- a/net/dccp/feat.c +++ /dev/null @@ -1,1581 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0-or-later -/* - * net/dccp/feat.c - * - * 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 Changing non-negotiable (NN) values is supported in state OPEN/PARTOPEN. - * 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. - */ -#include <linux/module.h> -#include <linux/slab.h> -#include "ccid.h" -#include "feat.h" - -/* feature-specific sysctls - initialised to the defaults from RFC 4340, 6.4 */ -unsigned long sysctl_dccp_sequence_window __read_mostly = 100; -int sysctl_dccp_rx_ccid __read_mostly = 2, - sysctl_dccp_tx_ccid __read_mostly = 2; - -/* - * Feature activation handlers. - * - * These all use an u64 argument, to provide enough room for NN/SP features. At - * this stage the negotiated values have been checked to be within their range. - */ -static int dccp_hdlr_ccid(struct sock *sk, u64 ccid, bool rx) -{ - struct dccp_sock *dp = dccp_sk(sk); - struct ccid *new_ccid = ccid_new(ccid, sk, rx); - - if (new_ccid == NULL) - return -ENOMEM; - - if (rx) { - ccid_hc_rx_delete(dp->dccps_hc_rx_ccid, sk); - dp->dccps_hc_rx_ccid = new_ccid; - } else { - ccid_hc_tx_delete(dp->dccps_hc_tx_ccid, sk); - dp->dccps_hc_tx_ccid = new_ccid; - } - return 0; -} - -static int dccp_hdlr_seq_win(struct sock *sk, u64 seq_win, bool rx) -{ - struct dccp_sock *dp = dccp_sk(sk); - - if (rx) { - dp->dccps_r_seq_win = seq_win; - /* propagate changes to update SWL/SWH */ - dccp_update_gsr(sk, dp->dccps_gsr); - } else { - dp->dccps_l_seq_win = seq_win; - /* propagate changes to update AWL */ - dccp_update_gss(sk, dp->dccps_gss); - } - return 0; -} - -static int dccp_hdlr_ack_ratio(struct sock *sk, u64 ratio, bool rx) -{ - if (rx) - dccp_sk(sk)->dccps_r_ack_ratio = ratio; - else - dccp_sk(sk)->dccps_l_ack_ratio = ratio; - return 0; -} - -static int dccp_hdlr_ackvec(struct sock *sk, u64 enable, bool rx) -{ - struct dccp_sock *dp = dccp_sk(sk); - - if (rx) { - if (enable && dp->dccps_hc_rx_ackvec == NULL) { - dp->dccps_hc_rx_ackvec = dccp_ackvec_alloc(gfp_any()); - if (dp->dccps_hc_rx_ackvec == NULL) - return -ENOMEM; - } else if (!enable) { - dccp_ackvec_free(dp->dccps_hc_rx_ackvec); - dp->dccps_hc_rx_ackvec = NULL; - } - } - return 0; -} - -static int dccp_hdlr_ndp(struct sock *sk, u64 enable, bool rx) -{ - if (!rx) - dccp_sk(sk)->dccps_send_ndp_count = (enable > 0); - return 0; -} - -/* - * Minimum Checksum Coverage is located at the RX side (9.2.1). This means that - * `rx' holds when the sending peer informs about his partial coverage via a - * ChangeR() option. In the other case, we are the sender and the receiver - * announces its coverage via ChangeL() options. The policy here is to honour - * such communication by enabling the corresponding partial coverage - but only - * if it has not been set manually before; the warning here means that all - * packets will be dropped. - */ -static int dccp_hdlr_min_cscov(struct sock *sk, u64 cscov, bool rx) -{ - struct dccp_sock *dp = dccp_sk(sk); - - if (rx) - dp->dccps_pcrlen = cscov; - else { - if (dp->dccps_pcslen == 0) - dp->dccps_pcslen = cscov; - else if (cscov > dp->dccps_pcslen) - DCCP_WARN("CsCov %u too small, peer requires >= %u\n", - dp->dccps_pcslen, (u8)cscov); - } - return 0; -} - -static const struct { - u8 feat_num; /* DCCPF_xxx */ - enum dccp_feat_type rxtx; /* RX or TX */ - enum dccp_feat_type reconciliation; /* SP or NN */ - u8 default_value; /* as in 6.4 */ - int (*activation_hdlr)(struct sock *sk, u64 val, bool rx); -/* - * Lookup table for location and type of features (from RFC 4340/4342) - * +--------------------------+----+-----+----+----+---------+-----------+ - * | 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 - * @feat_num: feature to hash, one of %dccp_feature_numbers - * - * 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; -} - -/* - * Debugging and verbose-printing section - */ -static const char *dccp_feat_fname(const u8 feat) -{ - static const char *const 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]; -} - -static const char *const dccp_feat_sname[] = { - "DEFAULT", "INITIALISING", "CHANGING", "UNSTABLE", "STABLE", -}; - -#ifdef CONFIG_IP_DCCP_DEBUG -static const char *dccp_feat_oname(const u8 opt) -{ - switch (opt) { - case DCCPO_CHANGE_L: return "Change_L"; - case DCCPO_CONFIRM_L: return "Confirm_L"; - case DCCPO_CHANGE_R: return "Change_R"; - case DCCPO_CONFIRM_R: return "Confirm_R"; - } - return NULL; -} - -static void dccp_feat_printval(u8 feat_num, dccp_feat_val const *val) -{ - u8 i, type = dccp_feat_type(feat_num); - - if (val == NULL || (type == FEAT_SP && val->sp.vec == NULL)) - dccp_pr_debug_cat("(NULL)"); - else if (type == FEAT_SP) - for (i = 0; i < val->sp.len; i++) - dccp_pr_debug_cat("%s%u", i ? " " : "", val->sp.vec[i]); - else if (type == FEAT_NN) - dccp_pr_debug_cat("%llu", (unsigned long long)val->nn); - else - dccp_pr_debug_cat("unknown type %u", type); -} - -static void dccp_feat_printvals(u8 feat_num, u8 *list, u8 len) -{ - u8 type = dccp_feat_type(feat_num); - dccp_feat_val fval = { .sp.vec = list, .sp.len = len }; - - if (type == FEAT_NN) - fval.nn = dccp_decode_value_var(list, len); - dccp_feat_printval(feat_num, &fval); -} - -static void dccp_feat_print_entry(struct dccp_feat_entry const *entry) -{ - dccp_debug(" * %s %s = ", entry->is_local ? "local" : "remote", - dccp_feat_fname(entry->feat_num)); - dccp_feat_printval(entry->feat_num, &entry->val); - dccp_pr_debug_cat(", state=%s %s\n", dccp_feat_sname[entry->state], - entry->needs_confirm ? "(Confirm pending)" : ""); -} - -#define dccp_feat_print_opt(opt, feat, val, len, mandatory) do { \ - dccp_pr_debug("%s(%s, ", dccp_feat_oname(opt), dccp_feat_fname(feat));\ - dccp_feat_printvals(feat, val, len); \ - dccp_pr_debug_cat(") %s\n", mandatory ? "!" : ""); } while (0) - -#define dccp_feat_print_fnlist(fn_list) { \ - const struct dccp_feat_entry *___entry; \ - \ - dccp_pr_debug("List Dump:\n"); \ - list_for_each_entry(___entry, fn_list, node) \ - dccp_feat_print_entry(___entry); \ -} -#else /* ! CONFIG_IP_DCCP_DEBUG */ -#define dccp_feat_print_opt(opt, feat, val, len, mandatory) -#define dccp_feat_print_fnlist(fn_list) -#endif - -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)); - - dccp_debug(" -> activating %s %s, %sval=%llu\n", rx ? "RX" : "TX", - dccp_feat_fname(dccp_feat_table[idx].feat_num), - fval ? "" : "default ", (unsigned long long)val); - - return dccp_feat_table[idx].activation_hdlr(sk, val, rx); -} - -/** - * dccp_feat_activate - Activate feature value on socket - * @sk: fully connected DCCP socket (after handshake is complete) - * @feat_num: feature to activate, one of %dccp_feature_numbers - * @local: whether local (1) or remote (0) @feat_num is meant - * @fval: the value (SP or NN) to activate, or NULL to use the default value - * - * For general use this function is preferable over __dccp_feat_activate(). - */ -static int dccp_feat_activate(struct sock *sk, u8 feat_num, bool local, - dccp_feat_val const *fval) -{ - return __dccp_feat_activate(sk, dccp_feat_index(feat_num), local, fval); -} - -/* 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 -ENOMEM; - } - } - 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 - * @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 = false; - new->empty_confirm = false; - 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 = true; - new->empty_confirm = (fval == NULL); - new->val.nn = 0; /* zeroes the whole structure */ - if (!new->empty_confirm) - new->val = *fval; - new->needs_mandatory = false; - - 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 - * @feat_num: feature to return length of, one of %dccp_feature_numbers - * - * 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; - } - } - dccp_feat_print_opt(opt, pos->feat_num, ptr, len, 0); - - 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; - - if (skb->sk->sk_state == DCCP_OPEN && - (opt == DCCPO_CONFIRM_R || opt == DCCPO_CONFIRM_L)) { - /* - * Confirms don't get retransmitted (6.6.3) once the - * connection is in state OPEN - */ - dccp_feat_list_pop(pos); - } else { - /* - * Enter CHANGING after transmitting the Change - * option (6.6.2). - */ - if (pos->state == FEAT_INITIALISING) - pos->state = FEAT_CHANGING; - } - } - return 0; -} - -/** - * __feat_register_nn - Register new NN value on socket - * @fn: feature-negotiation list to register with - * @feat: an NN feature from %dccp_feature_numbers - * @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; - - if (dccp_feat_push_change(fn, feat, is_local, mandatory, &fval)) { - kfree(fval.sp.vec); - return -ENOMEM; - } - - return 0; -} - -/** - * 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); -} - -/** - * dccp_feat_nn_get - Query current/pending value of NN feature - * @sk: DCCP socket of an established connection - * @feat: NN feature number from %dccp_feature_numbers - * - * For a known NN feature, returns value currently being negotiated, or - * current (confirmed) value if no negotiation is going on. - */ -u64 dccp_feat_nn_get(struct sock *sk, u8 feat) -{ - if (dccp_feat_type(feat) == FEAT_NN) { - struct dccp_sock *dp = dccp_sk(sk); - struct dccp_feat_entry *entry; - - entry = dccp_feat_list_lookup(&dp->dccps_featneg, feat, 1); - if (entry != NULL) - return entry->val.nn; - - switch (feat) { - case DCCPF_ACK_RATIO: - return dp->dccps_l_ack_ratio; - case DCCPF_SEQUENCE_WINDOW: - return dp->dccps_l_seq_win; - } - } - DCCP_BUG("attempt to look up unsupported feature %u", feat); - return 0; -} -EXPORT_SYMBOL_GPL(dccp_feat_nn_get); - -/** - * dccp_feat_signal_nn_change - Update NN values for an established connection - * @sk: DCCP socket of an established connection - * @feat: NN feature number from %dccp_feature_numbers - * @nn_val: the new value to use - * - * This function is used to communicate NN updates out-of-band. - */ -int dccp_feat_signal_nn_change(struct sock *sk, u8 feat, u64 nn_val) -{ - struct list_head *fn = &dccp_sk(sk)->dccps_featneg; - dccp_feat_val fval = { .nn = nn_val }; - struct dccp_feat_entry *entry; - - if (sk->sk_state != DCCP_OPEN && sk->sk_state != DCCP_PARTOPEN) - return 0; - - if (dccp_feat_type(feat) != FEAT_NN || - !dccp_feat_is_valid_nn_val(feat, nn_val)) - return -EINVAL; - - if (nn_val == dccp_feat_nn_get(sk, feat)) - return 0; /* already set or negotiation under way */ - - entry = dccp_feat_list_lookup(fn, feat, 1); - if (entry != NULL) { - dccp_pr_debug("Clobbering existing NN entry %llu -> %llu\n", - (unsigned long long)entry->val.nn, - (unsigned long long)nn_val); - dccp_feat_list_pop(entry); - } - - inet_csk_schedule_ack(sk); - return dccp_feat_push_change(fn, feat, 1, 0, &fval); -} -EXPORT_SYMBOL_GPL(dccp_feat_signal_nn_change); - -/* - * 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; - dccp_feat_print_fnlist(fn); - return 0; -} - -/** - * dccp_feat_server_ccid_dependencies - Resolve CCID-dependent features - * @dreq: server socket to resolve - * - * 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; -} - -/* 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 - * @preferred_value: entry to move to start of array - * @array: array of preferred entries - * @array_len: size of the 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 - * @fv: 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); -} - -/** - * 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) -{ - 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; - - dccp_feat_print_opt(opt, feat, val, len, is_mandatory); - - /* - * 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; - - return dccp_feat_push_confirm(fn, feat, local, &fval); - } - - /* - * 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; - } - - if (dccp_feat_push_confirm(fn, feat, local, &fval)) { - kfree(fval.sp.vec); - return DCCP_RESET_CODE_TOO_BUSY; - } - - return 0; - } else if (entry->state == FEAT_UNSTABLE) { /* 6.6.2 */ - return 0; - } - - if (dccp_feat_reconcile(&entry->val, val, len, server, true)) { - entry->empty_confirm = false; - } 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 = true; - } - entry->needs_confirm = true; - entry->needs_mandatory = false; - 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; -} - -/** - * 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); - - dccp_feat_print_opt(opt, feat, val, len, is_mandatory); - - 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_handle_nn_established - Fast-path reception of NN options - * @sk: socket of an established DCCP connection - * @mandatory: whether @opt was preceded by a Mandatory option - * @opt: %DCCPO_CHANGE_L | %DCCPO_CONFIRM_R (NN only) - * @feat: NN number, one of %dccp_feature_numbers - * @val: NN value - * @len: length of @val in bytes - * - * This function combines the functionality of change_recv/confirm_recv, with - * the following differences (reset codes are the same): - * - cleanup after receiving the Confirm; - * - values are directly activated after successful parsing; - * - deliberately restricted to NN features. - * The restriction to NN features is essential since SP features can have non- - * predictable outcomes (depending on the remote configuration), and are inter- - * dependent (CCIDs for instance cause further dependencies). - */ -static u8 dccp_feat_handle_nn_established(struct sock *sk, u8 mandatory, u8 opt, - u8 feat, u8 *val, u8 len) -{ - struct list_head *fn = &dccp_sk(sk)->dccps_featneg; - const bool local = (opt == DCCPO_CONFIRM_R); - struct dccp_feat_entry *entry; - u8 type = dccp_feat_type(feat); - dccp_feat_val fval; - - dccp_feat_print_opt(opt, feat, val, len, mandatory); - - /* Ignore non-mandatory unknown and non-NN features */ - if (type == FEAT_UNKNOWN) { - if (local && !mandatory) - return 0; - goto fast_path_unknown; - } else if (type != FEAT_NN) { - return 0; - } - - /* - * We don't accept empty Confirms, since in fast-path feature - * negotiation the values are enabled immediately after sending - * the Change option. - * Empty Changes on the other hand are invalid (RFC 4340, 6.1). - */ - if (len == 0 || len > sizeof(fval.nn)) - goto fast_path_unknown; - - if (opt == DCCPO_CHANGE_L) { - fval.nn = dccp_decode_value_var(val, len); - if (!dccp_feat_is_valid_nn_val(feat, fval.nn)) - goto fast_path_unknown; - - if (dccp_feat_push_confirm(fn, feat, local, &fval) || - dccp_feat_activate(sk, feat, local, &fval)) - return DCCP_RESET_CODE_TOO_BUSY; - - /* set the `Ack Pending' flag to piggyback a Confirm */ - inet_csk_schedule_ack(sk); - - } else if (opt == DCCPO_CONFIRM_R) { - entry = dccp_feat_list_lookup(fn, feat, local); - if (entry == NULL || entry->state != FEAT_CHANGING) - return 0; - - fval.nn = dccp_decode_value_var(val, len); - /* - * Just ignore a value that doesn't match our current value. - * If the option changes twice within two RTTs, then at least - * one CONFIRM will be received for the old value after a - * new CHANGE was sent. - */ - if (fval.nn != entry->val.nn) - return 0; - - /* Only activate after receiving the Confirm option (6.6.1). */ - dccp_feat_activate(sk, feat, local, &fval); - - /* It has been confirmed - so remove the entry */ - dccp_feat_list_pop(entry); - - } else { - DCCP_WARN("Received illegal option %u\n", opt); - goto fast_path_failed; - } - return 0; - -fast_path_unknown: - if (!mandatory) - return dccp_push_empty_confirm(fn, feat, local); - -fast_path_failed: - return 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; - fallthrough; - 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); - } - break; - /* - * Support for exchanging NN options on an established connection. - */ - case DCCP_OPEN: - case DCCP_PARTOPEN: - return dccp_feat_handle_nn_established(sk, mandatory, opt, feat, - val, len); - } - return 0; /* ignore FN options in all other states */ -} - -/** - * dccp_feat_init - Seed feature negotiation with host-specific defaults - * @sk: Socket to initialize. - * - * This initialises global defaults, depending on the value of the sysctls. - * These can later be overridden by registering changes via setsockopt calls. - * The last link in the chain is finalise_settings, to make sure that between - * here and the start of actual feature negotiation no inconsistencies enter. - * - * All features not appearing below use either defaults or are otherwise - * later adjusted through dccp_feat_finalise_settings(). - */ -int dccp_feat_init(struct sock *sk) -{ - struct list_head *fn = &dccp_sk(sk)->dccps_featneg; - u8 on = 1, off = 0; - int rc; - struct { - u8 *val; - u8 len; - } tx, rx; - - /* Non-negotiable (NN) features */ - rc = __feat_register_nn(fn, DCCPF_SEQUENCE_WINDOW, 0, - sysctl_dccp_sequence_window); - if (rc) - return rc; - - /* Server-priority (SP) features */ - - /* Advertise that short seqnos are not supported (7.6.1) */ - rc = __feat_register_sp(fn, DCCPF_SHORT_SEQNOS, true, true, &off, 1); - if (rc) - return rc; - - /* RFC 4340 12.1: "If a DCCP is not ECN capable, ..." */ - rc = __feat_register_sp(fn, DCCPF_ECN_INCAPABLE, true, true, &on, 1); - if (rc) - return rc; - - /* - * We advertise the available list of CCIDs and reorder according to - * preferences, to avoid failure resulting from negotiating different - * singleton values (which always leads to failure). - * These settings can still (later) be overridden via sockopts. - */ - if (ccid_get_builtin_ccids(&tx.val, &tx.len)) - return -ENOBUFS; - if (ccid_get_builtin_ccids(&rx.val, &rx.len)) { - kfree(tx.val); - return -ENOBUFS; - } - - if (!dccp_feat_prefer(sysctl_dccp_tx_ccid, tx.val, tx.len) || - !dccp_feat_prefer(sysctl_dccp_rx_ccid, rx.val, rx.len)) - goto free_ccid_lists; - - rc = __feat_register_sp(fn, DCCPF_CCID, true, false, tx.val, tx.len); - if (rc) - goto free_ccid_lists; - - rc = __feat_register_sp(fn, DCCPF_CCID, false, false, rx.val, rx.len); - -free_ccid_lists: - kfree(tx.val); - kfree(rx.val); - return rc; -} - -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 %s failed in state %s", - cur->is_local ? "local" : "remote", - dccp_feat_fname(cur->feat_num), - dccp_feat_sname[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; -} |