mirror of https://gitee.com/openkylin/linux.git
dccp: Processing Confirm options
Analogous to the previous patch, this adds code to interpret incoming Confirm feature-negotiation options. Both functions operate on the feature-negotiation list of either the request_sock (server) or the dccp_sock (client). Thanks to Wei Yongjun for pointing out that it is overly restrictive to check the entire list of confirmed SP values. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
This commit is contained in:
Gerrit Renker
parent
5a146b97d5
commit
d2150b7bff
100
net/dccp/feat.c
100
net/dccp/feat.c
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@ -99,6 +99,13 @@ static int dccp_feat_default_value(u8 feat_num)
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return idx < 0 ? : dccp_feat_table[idx].default_value;
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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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@ -1093,7 +1100,6 @@ int dccp_feat_change_recv(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len)
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}
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EXPORT_SYMBOL_GPL(dccp_feat_change_recv);
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#endif /* (later) */
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int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature,
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u8 *val, u8 len)
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@ -1148,6 +1154,7 @@ int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature,
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}
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EXPORT_SYMBOL_GPL(dccp_feat_confirm_recv);
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#endif /* (later) */
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void dccp_feat_clean(struct dccp_minisock *dmsk)
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{
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@ -1343,6 +1350,93 @@ static u8 dccp_feat_change_recv(struct list_head *fn, u8 is_mandatory, u8 opt,
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: DCCP_RESET_CODE_OPTION_ERROR;
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}
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/**
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* dccp_feat_confirm_recv - Process received Confirm options
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* @fn: feature-negotiation list to update
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* @is_mandatory: whether @opt was preceded by a Mandatory option
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* @opt: %DCCPO_CONFIRM_L or %DCCPO_CONFIRM_R
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* @feat: one of %dccp_feature_numbers
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* @val: NN value or SP value/preference list
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* @len: length of @val in bytes
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* @server: whether this node is server (1) or client (0)
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*/
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static u8 dccp_feat_confirm_recv(struct list_head *fn, u8 is_mandatory, u8 opt,
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u8 feat, u8 *val, u8 len, const bool server)
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{
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u8 *plist, plen, type = dccp_feat_type(feat);
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const bool local = (opt == DCCPO_CONFIRM_R);
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struct dccp_feat_entry *entry = dccp_feat_list_lookup(fn, feat, local);
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if (entry == NULL) { /* nothing queued: ignore or handle error */
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if (is_mandatory && type == FEAT_UNKNOWN)
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return DCCP_RESET_CODE_MANDATORY_ERROR;
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if (!local && type == FEAT_NN) /* 6.3.2 */
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goto confirmation_failed;
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return 0;
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}
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if (entry->state != FEAT_CHANGING) /* 6.6.2 */
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return 0;
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if (len == 0) {
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if (dccp_feat_must_be_understood(feat)) /* 6.6.7 */
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goto confirmation_failed;
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/*
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* Empty Confirm during connection setup: this means reverting
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* to the `old' value, which in this case is the default. Since
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* we handle default values automatically when no other values
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* have been set, we revert to the old value by removing this
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* entry from the list.
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*/
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dccp_feat_list_pop(entry);
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return 0;
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}
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if (type == FEAT_NN) {
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if (len > sizeof(entry->val.nn))
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goto confirmation_failed;
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if (entry->val.nn == dccp_decode_value_var(val, len))
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goto confirmation_succeeded;
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DCCP_WARN("Bogus Confirm for non-existing value\n");
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goto confirmation_failed;
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}
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/*
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* Parsing SP Confirms: the first element of @val is the preferred
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* SP value which the peer confirms, the remainder depends on @len.
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* Note that only the confirmed value need to be a valid SP value.
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*/
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if (!dccp_feat_is_valid_sp_val(feat, *val))
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goto confirmation_failed;
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if (len == 1) { /* peer didn't supply a preference list */
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plist = val;
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plen = len;
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} else { /* preferred value + preference list */
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plist = val + 1;
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plen = len - 1;
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}
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/* Check whether the peer got the reconciliation right (6.6.8) */
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if (dccp_feat_reconcile(&entry->val, plist, plen, server, 0) != *val) {
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DCCP_WARN("Confirm selected the wrong value %u\n", *val);
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return DCCP_RESET_CODE_OPTION_ERROR;
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}
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entry->val.sp.vec[0] = *val;
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confirmation_succeeded:
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entry->state = FEAT_STABLE;
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return 0;
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confirmation_failed:
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DCCP_WARN("Confirmation failed\n");
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return is_mandatory ? DCCP_RESET_CODE_MANDATORY_ERROR
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: DCCP_RESET_CODE_OPTION_ERROR;
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}
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/**
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* dccp_feat_parse_options - Process Feature-Negotiation Options
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* @sk: for general use and used by the client during connection setup
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@ -1373,6 +1467,10 @@ int dccp_feat_parse_options(struct sock *sk, struct dccp_request_sock *dreq,
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case DCCPO_CHANGE_R:
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return dccp_feat_change_recv(fn, mandatory, opt, feat,
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val, len, server);
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case DCCPO_CONFIRM_R:
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case DCCPO_CONFIRM_L:
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return dccp_feat_confirm_recv(fn, mandatory, opt, feat,
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val, len, server);
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}
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}
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return 0; /* ignore FN options in all other states */
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@ -117,8 +117,6 @@ extern int dccp_feat_register_sp(struct sock *sk, u8 feat, u8 is_local,
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extern int dccp_feat_register_nn(struct sock *sk, u8 feat, u64 val);
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extern int dccp_feat_parse_options(struct sock *, struct dccp_request_sock *,
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u8 mand, u8 opt, u8 feat, u8 *val, u8 len);
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extern int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature,
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u8 *val, u8 len);
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extern void dccp_feat_clean(struct dccp_minisock *dmsk);
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extern int dccp_feat_clone(struct sock *oldsk, struct sock *newsk);
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extern int dccp_feat_clone_list(struct list_head const *, struct list_head *);
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@ -134,26 +134,14 @@ int dccp_parse_options(struct sock *sk, struct dccp_request_sock *dreq,
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dccp_pr_debug("%s opt: NDP count=%llu\n", dccp_role(sk),
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(unsigned long long)opt_recv->dccpor_ndp);
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break;
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case DCCPO_CHANGE_L:
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case DCCPO_CHANGE_R:
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if (pkt_type == DCCP_PKT_DATA)
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case DCCPO_CHANGE_L ... DCCPO_CONFIRM_R:
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if (pkt_type == DCCP_PKT_DATA) /* RFC 4340, 6 */
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break;
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rc = dccp_feat_parse_options(sk, dreq, mandatory, opt,
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*value, value + 1, len - 1);
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if (rc)
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goto out_featneg_failed;
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break;
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case DCCPO_CONFIRM_L:
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/* fall through */
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case DCCPO_CONFIRM_R:
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if (pkt_type == DCCP_PKT_DATA)
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break;
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if (len < 2) /* FIXME this disallows empty confirm */
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goto out_invalid_option;
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if (dccp_feat_confirm_recv(sk, opt, *value,
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value + 1, len - 1))
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goto out_invalid_option;
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break;
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case DCCPO_ACK_VECTOR_0:
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case DCCPO_ACK_VECTOR_1:
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if (dccp_packet_without_ack(skb)) /* RFC 4340, 11.4 */
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