From 9eca0a47dee201a73967026985b5f0a79a46bd36 Mon Sep 17 00:00:00 2001 From: Gerrit Renker Date: Wed, 12 Nov 2008 00:48:44 -0800 Subject: dccp: Resolve dependencies of features on choice of CCID This provides a missing link in the code chain, as several features implicitly depend and/or rely on the choice of CCID. Most notably, this is the Send Ack Vector feature, but also Ack Ratio and Send Loss Event Rate (also taken care of). For Send Ack Vector, the situation is as follows: * since CCID2 mandates the use of Ack Vectors, there is no point in allowing endpoints which use CCID2 to disable Ack Vector features such a connection; * a peer with a TX CCID of CCID2 will always expect Ack Vectors, and a peer with a RX CCID of CCID2 must always send Ack Vectors (RFC 4341, sec. 4); * for all other CCIDs, the use of (Send) Ack Vector is optional and thus negotiable. However, this implies that the code negotiating the use of Ack Vectors also supports it (i.e. is able to supply and to either parse or ignore received Ack Vectors). Since this is not the case (CCID-3 has no Ack Vector support), the use of Ack Vectors is here disabled, with a comment in the source code. An analogous consideration arises for the Send Loss Event Rate feature, since the CCID-3 implementation does not support the loss interval options of RFC 4342. To make such use explicit, corresponding feature-negotiation options are inserted which signal the use of the loss event rate option, as it is used by the CCID3 code. Lastly, the values of the Ack Ratio feature are matched to the choice of CCID. The patch implements this as a function which is called after the user has made all other registrations for changing default values of features. The table is variable-length, the reserved (and hence for feature-negotiation invalid, confirmed by considering section 19.4 of RFC 4340) feature number `0' is used to mark the end of the table. Signed-off-by: Gerrit Renker Acked-by: Ian McDonald Signed-off-by: David S. Miller --- net/dccp/output.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'net/dccp/output.c') diff --git a/net/dccp/output.c b/net/dccp/output.c index 809d803d5006..92f3f6f2ef51 100644 --- a/net/dccp/output.c +++ b/net/dccp/output.c @@ -469,6 +469,10 @@ int dccp_connect(struct sock *sk) struct sk_buff *skb; struct inet_connection_sock *icsk = inet_csk(sk); + /* do not connect if feature negotiation setup fails */ + if (dccp_feat_finalise_settings(dccp_sk(sk))) + return -EPROTO; + dccp_connect_init(sk); skb = alloc_skb(sk->sk_prot->max_header, sk->sk_allocation); -- cgit v1.2.3 From 0c1168398ecbfacbb27203b281bde20ec9f78017 Mon Sep 17 00:00:00 2001 From: Gerrit Renker Date: Sun, 16 Nov 2008 22:49:52 -0800 Subject: dccp: Mechanism to resolve CCID dependencies This adds a hook to resolve features whose value depends on the choice of CCID. It is done at the server since it can only be done after the CCID values have been negotiated; i.e. the client will add its CCID preference list on the Change options sent in the Request, which will be reconciled with the local preference list of the server. The concept is documented on http://www.erg.abdn.ac.uk/users/gerrit/dccp/notes/feature_negotiation/\ implementation_notes.html#ccid_dependencies Signed-off-by: Gerrit Renker Acked-by: Ian McDonald Signed-off-by: David S. Miller --- net/dccp/dccp.h | 1 + net/dccp/feat.c | 37 +++++++++++++++++++++++++++++++++++++ net/dccp/output.c | 13 +++++++++---- 3 files changed, 47 insertions(+), 4 deletions(-) (limited to 'net/dccp/output.c') diff --git a/net/dccp/dccp.h b/net/dccp/dccp.h index 1881527bdcd7..e656dafb5d96 100644 --- a/net/dccp/dccp.h +++ b/net/dccp/dccp.h @@ -443,6 +443,7 @@ static inline int dccp_ack_pending(const struct sock *sk) } extern int dccp_feat_finalise_settings(struct dccp_sock *dp); +extern int dccp_feat_server_ccid_dependencies(struct dccp_request_sock *dreq); extern void dccp_feat_list_purge(struct list_head *fn_list); extern int dccp_insert_options(struct sock *sk, struct sk_buff *skb); diff --git a/net/dccp/feat.c b/net/dccp/feat.c index 4c4144147325..4f86a48723f6 100644 --- a/net/dccp/feat.c +++ b/net/dccp/feat.c @@ -166,6 +166,18 @@ static void dccp_feat_entry_destructor(struct dccp_feat_entry *entry) * - 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) @@ -560,6 +572,31 @@ int dccp_feat_finalise_settings(struct dccp_sock *dp) return 0; } +/** + * dccp_feat_server_ccid_dependencies - Resolve CCID-dependent features + * 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; +} + static int dccp_feat_update_ccid(struct sock *sk, u8 type, u8 new_ccid_nr) { struct dccp_sock *dp = dccp_sk(sk); diff --git a/net/dccp/output.c b/net/dccp/output.c index 92f3f6f2ef51..fea30cdc0bee 100644 --- a/net/dccp/output.c +++ b/net/dccp/output.c @@ -339,10 +339,12 @@ struct sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst, DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESPONSE; DCCP_SKB_CB(skb)->dccpd_seq = dreq->dreq_iss; - if (dccp_insert_options_rsk(dreq, skb)) { - kfree_skb(skb); - return NULL; - } + /* Resolve feature dependencies resulting from choice of CCID */ + if (dccp_feat_server_ccid_dependencies(dreq)) + goto response_failed; + + if (dccp_insert_options_rsk(dreq, skb)) + goto response_failed; /* Build and checksum header */ dh = dccp_zeroed_hdr(skb, dccp_header_size); @@ -363,6 +365,9 @@ struct sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst, inet_rsk(req)->acked = 1; DCCP_INC_STATS(DCCP_MIB_OUTSEGS); return skb; +response_failed: + kfree_skb(skb); + return NULL; } EXPORT_SYMBOL_GPL(dccp_make_response); -- cgit v1.2.3 From 61c1d052a3c7d5acba3bd535aaffa5bb5d085181 Mon Sep 17 00:00:00 2001 From: Ilpo Järvinen Date: Fri, 5 Dec 2008 22:39:49 -0800 Subject: dccp: use roundup instead of opencoding MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Signed-off-by: Ilpo Järvinen Signed-off-by: David S. Miller --- net/dccp/output.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net/dccp/output.c') diff --git a/net/dccp/output.c b/net/dccp/output.c index fea30cdc0bee..22a618af4893 100644 --- a/net/dccp/output.c +++ b/net/dccp/output.c @@ -175,7 +175,7 @@ unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu) * make it a multiple of 4 */ - cur_mps -= ((5 + 6 + 10 + 6 + 6 + 6 + 3) / 4) * 4; + cur_mps -= roundup(5 + 6 + 10 + 6 + 6 + 6, 4); /* And store cached results */ icsk->icsk_pmtu_cookie = pmtu; -- cgit v1.2.3