From: Gerrit Renker <gerrit@xxxxxxxxxxxxxx>
This adds option-parsing code to processing of Acks in the listening state
on request_socks on the server, serving two purposes
(i) resolves a FIXME (removed);
(ii) paves the way for feature-negotiation during connection-setup.
There is an intended subtlety here with regard to dccp_check_req:
Parsing options happens only after testing whether the received packet is
a retransmitted Request. Otherwise, if the Request contained (a possibly
large number of) feature-negotiation options, recomputing state would have to
happen each time a retransmitted Request arrives, which opens the door to an
easy DoS attack. Since in a genuine retransmission the options should not be
different from the original, reusing the already computed state seems better.
The other point is - if there are timestamp options on the Request, they will
not be answered; which means that in the presence of retransmission (likely
due to loss and/or other problems), the use of Request/Response RTT sampling
is suspended, so that startup problems here do not propagate.
Signed-off-by: Gerrit Renker <gerrit@xxxxxxxxxxxxxx>
Signed-off-by: Ian McDonald <ian.mcdonald@xxxxxxxxxxx>
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
net/dccp/minisocks.c | 12 ++++++------
1 files changed, 6 insertions(+), 6 deletions(-)
diff --git a/net/dccp/minisocks.c b/net/dccp/minisocks.c
index 831b76e..b1d5da6 100644
--- a/net/dccp/minisocks.c
+++ b/net/dccp/minisocks.c
@@ -200,10 +200,10 @@ struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb,
struct request_sock **prev)
{
struct sock *child = NULL;
+ struct dccp_request_sock *dreq = dccp_rsk(req);
/* Check for retransmitted REQUEST */
if (dccp_hdr(skb)->dccph_type == DCCP_PKT_REQUEST) {
- struct dccp_request_sock *dreq = dccp_rsk(req);
if (after48(DCCP_SKB_CB(skb)->dccpd_seq, dreq->dreq_isr)) {
dccp_pr_debug("Retransmitted REQUEST\n");
@@ -227,22 +227,22 @@ struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb,
goto drop;
/* Invalid ACK */
- if (DCCP_SKB_CB(skb)->dccpd_ack_seq != dccp_rsk(req)->dreq_iss) {
+ if (DCCP_SKB_CB(skb)->dccpd_ack_seq != dreq->dreq_iss) {
dccp_pr_debug("Invalid ACK number: ack_seq=%llu, "
"dreq_iss=%llu\n",
(unsigned long long)
DCCP_SKB_CB(skb)->dccpd_ack_seq,
- (unsigned long long)
- dccp_rsk(req)->dreq_iss);
+ (unsigned long long) dreq->dreq_iss);
goto drop;
}
+ if (dccp_parse_options(sk, dreq, skb))
+ goto drop;
+
child = inet_csk(sk)->icsk_af_ops->syn_recv_sock(sk, skb, req, NULL);
if (child == NULL)
goto listen_overflow;
- /* FIXME: deal with options */
-
inet_csk_reqsk_queue_unlink(sk, req, prev);
inet_csk_reqsk_queue_removed(sk, req);
inet_csk_reqsk_queue_add(sk, req, child);
--
1.5.3.4
-
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