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1577 lines
47 KiB
1577 lines
47 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* net/dccp/feat.c |
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* |
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* Feature negotiation for the DCCP protocol (RFC 4340, section 6) |
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* |
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* Copyright (c) 2008 Gerrit Renker <[email protected]> |
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* Rewrote from scratch, some bits from earlier code by |
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* Copyright (c) 2005 Andrea Bittau <[email protected]> |
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* |
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* ASSUMPTIONS |
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* ----------- |
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* o Feature negotiation is coordinated with connection setup (as in TCP), wild |
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* changes of parameters of an established connection are not supported. |
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* o Changing non-negotiable (NN) values is supported in state OPEN/PARTOPEN. |
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* o All currently known SP features have 1-byte quantities. If in the future |
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* extensions of RFCs 4340..42 define features with item lengths larger than |
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* one byte, a feature-specific extension of the code will be required. |
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*/ |
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#include <linux/module.h> |
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#include <linux/slab.h> |
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#include "ccid.h" |
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#include "feat.h" |
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|
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/* feature-specific sysctls - initialised to the defaults from RFC 4340, 6.4 */ |
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unsigned long sysctl_dccp_sequence_window __read_mostly = 100; |
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int sysctl_dccp_rx_ccid __read_mostly = 2, |
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sysctl_dccp_tx_ccid __read_mostly = 2; |
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|
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/* |
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* Feature activation handlers. |
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* |
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* These all use an u64 argument, to provide enough room for NN/SP features. At |
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* this stage the negotiated values have been checked to be within their range. |
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*/ |
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static int dccp_hdlr_ccid(struct sock *sk, u64 ccid, bool rx) |
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{ |
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struct dccp_sock *dp = dccp_sk(sk); |
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struct ccid *new_ccid = ccid_new(ccid, sk, rx); |
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|
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if (new_ccid == NULL) |
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return -ENOMEM; |
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|
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if (rx) { |
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ccid_hc_rx_delete(dp->dccps_hc_rx_ccid, sk); |
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dp->dccps_hc_rx_ccid = new_ccid; |
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} else { |
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ccid_hc_tx_delete(dp->dccps_hc_tx_ccid, sk); |
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dp->dccps_hc_tx_ccid = new_ccid; |
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} |
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return 0; |
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} |
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|
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static int dccp_hdlr_seq_win(struct sock *sk, u64 seq_win, bool rx) |
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{ |
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struct dccp_sock *dp = dccp_sk(sk); |
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|
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if (rx) { |
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dp->dccps_r_seq_win = seq_win; |
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/* propagate changes to update SWL/SWH */ |
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dccp_update_gsr(sk, dp->dccps_gsr); |
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} else { |
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dp->dccps_l_seq_win = seq_win; |
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/* propagate changes to update AWL */ |
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dccp_update_gss(sk, dp->dccps_gss); |
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} |
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return 0; |
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} |
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|
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static int dccp_hdlr_ack_ratio(struct sock *sk, u64 ratio, bool rx) |
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{ |
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if (rx) |
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dccp_sk(sk)->dccps_r_ack_ratio = ratio; |
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else |
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dccp_sk(sk)->dccps_l_ack_ratio = ratio; |
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return 0; |
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} |
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|
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static int dccp_hdlr_ackvec(struct sock *sk, u64 enable, bool rx) |
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{ |
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struct dccp_sock *dp = dccp_sk(sk); |
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|
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if (rx) { |
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if (enable && dp->dccps_hc_rx_ackvec == NULL) { |
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dp->dccps_hc_rx_ackvec = dccp_ackvec_alloc(gfp_any()); |
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if (dp->dccps_hc_rx_ackvec == NULL) |
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return -ENOMEM; |
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} else if (!enable) { |
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dccp_ackvec_free(dp->dccps_hc_rx_ackvec); |
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dp->dccps_hc_rx_ackvec = NULL; |
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} |
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} |
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return 0; |
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} |
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|
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static int dccp_hdlr_ndp(struct sock *sk, u64 enable, bool rx) |
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{ |
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if (!rx) |
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dccp_sk(sk)->dccps_send_ndp_count = (enable > 0); |
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return 0; |
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} |
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|
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/* |
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* Minimum Checksum Coverage is located at the RX side (9.2.1). This means that |
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* `rx' holds when the sending peer informs about his partial coverage via a |
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* ChangeR() option. In the other case, we are the sender and the receiver |
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* announces its coverage via ChangeL() options. The policy here is to honour |
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* such communication by enabling the corresponding partial coverage - but only |
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* if it has not been set manually before; the warning here means that all |
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* packets will be dropped. |
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*/ |
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static int dccp_hdlr_min_cscov(struct sock *sk, u64 cscov, bool rx) |
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{ |
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struct dccp_sock *dp = dccp_sk(sk); |
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|
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if (rx) |
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dp->dccps_pcrlen = cscov; |
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else { |
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if (dp->dccps_pcslen == 0) |
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dp->dccps_pcslen = cscov; |
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else if (cscov > dp->dccps_pcslen) |
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DCCP_WARN("CsCov %u too small, peer requires >= %u\n", |
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dp->dccps_pcslen, (u8)cscov); |
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} |
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return 0; |
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} |
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|
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static const struct { |
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u8 feat_num; /* DCCPF_xxx */ |
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enum dccp_feat_type rxtx; /* RX or TX */ |
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enum dccp_feat_type reconciliation; /* SP or NN */ |
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u8 default_value; /* as in 6.4 */ |
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int (*activation_hdlr)(struct sock *sk, u64 val, bool rx); |
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/* |
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* Lookup table for location and type of features (from RFC 4340/4342) |
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* +--------------------------+----+-----+----+----+---------+-----------+ |
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* | Feature | Location | Reconc. | Initial | Section | |
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* | | RX | TX | SP | NN | Value | Reference | |
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* +--------------------------+----+-----+----+----+---------+-----------+ |
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* | DCCPF_CCID | | X | X | | 2 | 10 | |
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* | DCCPF_SHORT_SEQNOS | | X | X | | 0 | 7.6.1 | |
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* | DCCPF_SEQUENCE_WINDOW | | X | | X | 100 | 7.5.2 | |
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* | DCCPF_ECN_INCAPABLE | X | | X | | 0 | 12.1 | |
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* | DCCPF_ACK_RATIO | | X | | X | 2 | 11.3 | |
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* | DCCPF_SEND_ACK_VECTOR | X | | X | | 0 | 11.5 | |
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* | DCCPF_SEND_NDP_COUNT | | X | X | | 0 | 7.7.2 | |
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* | DCCPF_MIN_CSUM_COVER | X | | X | | 0 | 9.2.1 | |
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* | DCCPF_DATA_CHECKSUM | X | | X | | 0 | 9.3.1 | |
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* | DCCPF_SEND_LEV_RATE | X | | X | | 0 | 4342/8.4 | |
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* +--------------------------+----+-----+----+----+---------+-----------+ |
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*/ |
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} dccp_feat_table[] = { |
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{ DCCPF_CCID, FEAT_AT_TX, FEAT_SP, 2, dccp_hdlr_ccid }, |
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{ DCCPF_SHORT_SEQNOS, FEAT_AT_TX, FEAT_SP, 0, NULL }, |
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{ DCCPF_SEQUENCE_WINDOW, FEAT_AT_TX, FEAT_NN, 100, dccp_hdlr_seq_win }, |
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{ DCCPF_ECN_INCAPABLE, FEAT_AT_RX, FEAT_SP, 0, NULL }, |
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{ DCCPF_ACK_RATIO, FEAT_AT_TX, FEAT_NN, 2, dccp_hdlr_ack_ratio}, |
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{ DCCPF_SEND_ACK_VECTOR, FEAT_AT_RX, FEAT_SP, 0, dccp_hdlr_ackvec }, |
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{ DCCPF_SEND_NDP_COUNT, FEAT_AT_TX, FEAT_SP, 0, dccp_hdlr_ndp }, |
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{ DCCPF_MIN_CSUM_COVER, FEAT_AT_RX, FEAT_SP, 0, dccp_hdlr_min_cscov}, |
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{ DCCPF_DATA_CHECKSUM, FEAT_AT_RX, FEAT_SP, 0, NULL }, |
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{ DCCPF_SEND_LEV_RATE, FEAT_AT_RX, FEAT_SP, 0, NULL }, |
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}; |
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#define DCCP_FEAT_SUPPORTED_MAX ARRAY_SIZE(dccp_feat_table) |
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|
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/** |
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* dccp_feat_index - Hash function to map feature number into array position |
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* @feat_num: feature to hash, one of %dccp_feature_numbers |
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* |
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* Returns consecutive array index or -1 if the feature is not understood. |
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*/ |
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static int dccp_feat_index(u8 feat_num) |
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{ |
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/* The first 9 entries are occupied by the types from RFC 4340, 6.4 */ |
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if (feat_num > DCCPF_RESERVED && feat_num <= DCCPF_DATA_CHECKSUM) |
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return feat_num - 1; |
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|
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/* |
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* Other features: add cases for new feature types here after adding |
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* them to the above table. |
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*/ |
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switch (feat_num) { |
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case DCCPF_SEND_LEV_RATE: |
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return DCCP_FEAT_SUPPORTED_MAX - 1; |
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} |
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return -1; |
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} |
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static u8 dccp_feat_type(u8 feat_num) |
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{ |
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int idx = dccp_feat_index(feat_num); |
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|
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if (idx < 0) |
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return FEAT_UNKNOWN; |
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return dccp_feat_table[idx].reconciliation; |
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} |
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static int dccp_feat_default_value(u8 feat_num) |
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{ |
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int idx = dccp_feat_index(feat_num); |
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/* |
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* There are no default values for unknown features, so encountering a |
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* negative index here indicates a serious problem somewhere else. |
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*/ |
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DCCP_BUG_ON(idx < 0); |
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|
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return idx < 0 ? 0 : dccp_feat_table[idx].default_value; |
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} |
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|
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/* |
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* Debugging and verbose-printing section |
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*/ |
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static const char *dccp_feat_fname(const u8 feat) |
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{ |
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static const char *const feature_names[] = { |
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[DCCPF_RESERVED] = "Reserved", |
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[DCCPF_CCID] = "CCID", |
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[DCCPF_SHORT_SEQNOS] = "Allow Short Seqnos", |
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[DCCPF_SEQUENCE_WINDOW] = "Sequence Window", |
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[DCCPF_ECN_INCAPABLE] = "ECN Incapable", |
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[DCCPF_ACK_RATIO] = "Ack Ratio", |
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[DCCPF_SEND_ACK_VECTOR] = "Send ACK Vector", |
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[DCCPF_SEND_NDP_COUNT] = "Send NDP Count", |
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[DCCPF_MIN_CSUM_COVER] = "Min. Csum Coverage", |
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[DCCPF_DATA_CHECKSUM] = "Send Data Checksum", |
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}; |
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if (feat > DCCPF_DATA_CHECKSUM && feat < DCCPF_MIN_CCID_SPECIFIC) |
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return feature_names[DCCPF_RESERVED]; |
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|
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if (feat == DCCPF_SEND_LEV_RATE) |
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return "Send Loss Event Rate"; |
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if (feat >= DCCPF_MIN_CCID_SPECIFIC) |
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return "CCID-specific"; |
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|
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return feature_names[feat]; |
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} |
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static const char *const dccp_feat_sname[] = { |
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"DEFAULT", "INITIALISING", "CHANGING", "UNSTABLE", "STABLE", |
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}; |
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|
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#ifdef CONFIG_IP_DCCP_DEBUG |
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static const char *dccp_feat_oname(const u8 opt) |
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{ |
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switch (opt) { |
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case DCCPO_CHANGE_L: return "Change_L"; |
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case DCCPO_CONFIRM_L: return "Confirm_L"; |
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case DCCPO_CHANGE_R: return "Change_R"; |
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case DCCPO_CONFIRM_R: return "Confirm_R"; |
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} |
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return NULL; |
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} |
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static void dccp_feat_printval(u8 feat_num, dccp_feat_val const *val) |
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{ |
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u8 i, type = dccp_feat_type(feat_num); |
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if (val == NULL || (type == FEAT_SP && val->sp.vec == NULL)) |
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dccp_pr_debug_cat("(NULL)"); |
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else if (type == FEAT_SP) |
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for (i = 0; i < val->sp.len; i++) |
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dccp_pr_debug_cat("%s%u", i ? " " : "", val->sp.vec[i]); |
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else if (type == FEAT_NN) |
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dccp_pr_debug_cat("%llu", (unsigned long long)val->nn); |
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else |
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dccp_pr_debug_cat("unknown type %u", type); |
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} |
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static void dccp_feat_printvals(u8 feat_num, u8 *list, u8 len) |
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{ |
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u8 type = dccp_feat_type(feat_num); |
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dccp_feat_val fval = { .sp.vec = list, .sp.len = len }; |
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|
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if (type == FEAT_NN) |
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fval.nn = dccp_decode_value_var(list, len); |
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dccp_feat_printval(feat_num, &fval); |
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} |
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static void dccp_feat_print_entry(struct dccp_feat_entry const *entry) |
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{ |
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dccp_debug(" * %s %s = ", entry->is_local ? "local" : "remote", |
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dccp_feat_fname(entry->feat_num)); |
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dccp_feat_printval(entry->feat_num, &entry->val); |
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dccp_pr_debug_cat(", state=%s %s\n", dccp_feat_sname[entry->state], |
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entry->needs_confirm ? "(Confirm pending)" : ""); |
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} |
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#define dccp_feat_print_opt(opt, feat, val, len, mandatory) do { \ |
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dccp_pr_debug("%s(%s, ", dccp_feat_oname(opt), dccp_feat_fname(feat));\ |
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dccp_feat_printvals(feat, val, len); \ |
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dccp_pr_debug_cat(") %s\n", mandatory ? "!" : ""); } while (0) |
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|
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#define dccp_feat_print_fnlist(fn_list) { \ |
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const struct dccp_feat_entry *___entry; \ |
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\ |
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dccp_pr_debug("List Dump:\n"); \ |
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list_for_each_entry(___entry, fn_list, node) \ |
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dccp_feat_print_entry(___entry); \ |
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} |
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#else /* ! CONFIG_IP_DCCP_DEBUG */ |
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#define dccp_feat_print_opt(opt, feat, val, len, mandatory) |
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#define dccp_feat_print_fnlist(fn_list) |
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#endif |
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static int __dccp_feat_activate(struct sock *sk, const int idx, |
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const bool is_local, dccp_feat_val const *fval) |
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{ |
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bool rx; |
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u64 val; |
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|
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if (idx < 0 || idx >= DCCP_FEAT_SUPPORTED_MAX) |
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return -1; |
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if (dccp_feat_table[idx].activation_hdlr == NULL) |
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return 0; |
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|
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if (fval == NULL) { |
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val = dccp_feat_table[idx].default_value; |
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} else if (dccp_feat_table[idx].reconciliation == FEAT_SP) { |
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if (fval->sp.vec == NULL) { |
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/* |
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* This can happen when an empty Confirm is sent |
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* for an SP (i.e. known) feature. In this case |
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* we would be using the default anyway. |
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*/ |
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DCCP_CRIT("Feature #%d undefined: using default", idx); |
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val = dccp_feat_table[idx].default_value; |
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} else { |
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val = fval->sp.vec[0]; |
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} |
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} else { |
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val = fval->nn; |
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} |
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|
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/* Location is RX if this is a local-RX or remote-TX feature */ |
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rx = (is_local == (dccp_feat_table[idx].rxtx == FEAT_AT_RX)); |
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|
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dccp_debug(" -> activating %s %s, %sval=%llu\n", rx ? "RX" : "TX", |
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dccp_feat_fname(dccp_feat_table[idx].feat_num), |
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fval ? "" : "default ", (unsigned long long)val); |
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|
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return dccp_feat_table[idx].activation_hdlr(sk, val, rx); |
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} |
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|
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/** |
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* dccp_feat_activate - Activate feature value on socket |
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* @sk: fully connected DCCP socket (after handshake is complete) |
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* @feat_num: feature to activate, one of %dccp_feature_numbers |
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* @local: whether local (1) or remote (0) @feat_num is meant |
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* @fval: the value (SP or NN) to activate, or NULL to use the default value |
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* |
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* For general use this function is preferable over __dccp_feat_activate(). |
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*/ |
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static int dccp_feat_activate(struct sock *sk, u8 feat_num, bool local, |
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dccp_feat_val const *fval) |
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{ |
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return __dccp_feat_activate(sk, dccp_feat_index(feat_num), local, fval); |
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} |
|
|
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/* Test for "Req'd" feature (RFC 4340, 6.4) */ |
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static inline int dccp_feat_must_be_understood(u8 feat_num) |
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{ |
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return feat_num == DCCPF_CCID || feat_num == DCCPF_SHORT_SEQNOS || |
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feat_num == DCCPF_SEQUENCE_WINDOW; |
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} |
|
|
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/* copy constructor, fval must not already contain allocated memory */ |
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static int dccp_feat_clone_sp_val(dccp_feat_val *fval, u8 const *val, u8 len) |
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{ |
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fval->sp.len = len; |
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if (fval->sp.len > 0) { |
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fval->sp.vec = kmemdup(val, len, gfp_any()); |
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if (fval->sp.vec == NULL) { |
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fval->sp.len = 0; |
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return -ENOMEM; |
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} |
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} |
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return 0; |
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} |
|
|
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static void dccp_feat_val_destructor(u8 feat_num, dccp_feat_val *val) |
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{ |
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if (unlikely(val == NULL)) |
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return; |
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if (dccp_feat_type(feat_num) == FEAT_SP) |
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kfree(val->sp.vec); |
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memset(val, 0, sizeof(*val)); |
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} |
|
|
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static struct dccp_feat_entry * |
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dccp_feat_clone_entry(struct dccp_feat_entry const *original) |
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{ |
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struct dccp_feat_entry *new; |
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u8 type = dccp_feat_type(original->feat_num); |
|
|
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if (type == FEAT_UNKNOWN) |
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return NULL; |
|
|
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new = kmemdup(original, sizeof(struct dccp_feat_entry), gfp_any()); |
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if (new == NULL) |
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return NULL; |
|
|
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if (type == FEAT_SP && dccp_feat_clone_sp_val(&new->val, |
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original->val.sp.vec, |
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original->val.sp.len)) { |
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kfree(new); |
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return NULL; |
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} |
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return new; |
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} |
|
|
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static void dccp_feat_entry_destructor(struct dccp_feat_entry *entry) |
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{ |
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if (entry != NULL) { |
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dccp_feat_val_destructor(entry->feat_num, &entry->val); |
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kfree(entry); |
|
} |
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} |
|
|
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/* |
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* List management functions |
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* |
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* Feature negotiation lists rely on and maintain the following invariants: |
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* - each feat_num in the list is known, i.e. we know its type and default value |
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* - each feat_num/is_local combination is unique (old entries are overwritten) |
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* - SP values are always freshly allocated |
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* - list is sorted in increasing order of feature number (faster lookup) |
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*/ |
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static struct dccp_feat_entry *dccp_feat_list_lookup(struct list_head *fn_list, |
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u8 feat_num, bool is_local) |
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{ |
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struct dccp_feat_entry *entry; |
|
|
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list_for_each_entry(entry, fn_list, node) { |
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if (entry->feat_num == feat_num && entry->is_local == is_local) |
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return entry; |
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else if (entry->feat_num > feat_num) |
|
break; |
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} |
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return NULL; |
|
} |
|
|
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/** |
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* dccp_feat_entry_new - Central list update routine (called by all others) |
|
* @head: list to add to |
|
* @feat: feature number |
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* @local: whether the local (1) or remote feature with number @feat is meant |
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* |
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* This is the only constructor and serves to ensure the above invariants. |
|
*/ |
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static struct dccp_feat_entry * |
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dccp_feat_entry_new(struct list_head *head, u8 feat, bool local) |
|
{ |
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struct dccp_feat_entry *entry; |
|
|
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list_for_each_entry(entry, head, node) |
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if (entry->feat_num == feat && entry->is_local == local) { |
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dccp_feat_val_destructor(entry->feat_num, &entry->val); |
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return entry; |
|
} else if (entry->feat_num > feat) { |
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head = &entry->node; |
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break; |
|
} |
|
|
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entry = kmalloc(sizeof(*entry), gfp_any()); |
|
if (entry != NULL) { |
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entry->feat_num = feat; |
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entry->is_local = local; |
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list_add_tail(&entry->node, head); |
|
} |
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return entry; |
|
} |
|
|
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/** |
|
* 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; |
|
} |
|
|
|
return dccp_feat_push_confirm(fn, feat, local, &fval); |
|
|
|
} else if (entry->state == FEAT_UNSTABLE) { /* 6.6.2 */ |
|
return 0; |
|
} |
|
|
|
if (dccp_feat_reconcile(&entry->val, val, len, server, true)) { |
|
entry->empty_confirm = 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; |
|
}
|
|
|