1578 lines
47 KiB
C
1578 lines
47 KiB
C
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// 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 <gerrit@erg.abdn.ac.uk>
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* Rewrote from scratch, some bits from earlier code by
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* Copyright (c) 2005 Andrea Bittau <a.bittau@cs.ucl.ac.uk>
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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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/* 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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* 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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if (new_ccid == NULL)
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return -ENOMEM;
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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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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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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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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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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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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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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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* 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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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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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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* 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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* 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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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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return idx < 0 ? 0 : dccp_feat_table[idx].default_value;
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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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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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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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#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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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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#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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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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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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/* 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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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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return dccp_feat_table[idx].activation_hdlr(sk, val, rx);
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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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||
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/* Test for "Req'd" feature (RFC 4340, 6.4) */
|
||
|
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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||
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/* 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;
|
||
|
}
|
||
|
|
||
|
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;
|
||
|
}
|