diff options
Diffstat (limited to 'net/dccp/feat.c')
| -rw-r--r-- | net/dccp/feat.c | 100 |
1 files changed, 99 insertions, 1 deletions
diff --git a/net/dccp/feat.c b/net/dccp/feat.c index 283c7fb8c7d..bc00c038e4a 100644 --- a/net/dccp/feat.c +++ b/net/dccp/feat.c @@ -104,6 +104,13 @@ static int dccp_feat_default_value(u8 feat_num) return idx < 0 ? 0 : dccp_feat_table[idx].default_value; } +/* Test for "Req'd" feature (RFC 4340, 6.4) */ +static inline int dccp_feat_must_be_understood(u8 feat_num) +{ + return feat_num == DCCPF_CCID || feat_num == DCCPF_SHORT_SEQNOS || + feat_num == DCCPF_SEQUENCE_WINDOW; +} + /* copy constructor, fval must not already contain allocated memory */ static int dccp_feat_clone_sp_val(dccp_feat_val *fval, u8 const *val, u8 len) { @@ -1099,7 +1106,6 @@ int dccp_feat_change_recv(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len) } EXPORT_SYMBOL_GPL(dccp_feat_change_recv); -#endif /* (later) */ int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len) @@ -1154,6 +1160,7 @@ int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature, } EXPORT_SYMBOL_GPL(dccp_feat_confirm_recv); +#endif /* (later) */ void dccp_feat_clean(struct dccp_minisock *dmsk) { @@ -1350,6 +1357,93 @@ not_valid_or_not_known: } /** + * 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); + + 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_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 @@ -1379,6 +1473,10 @@ int dccp_feat_parse_options(struct sock *sk, struct dccp_request_sock *dreq, 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); } } return 0; /* ignore FN options in all other states */ |