[DCCP]: Twice the wrong reset code in receiving connection-Requests
This fixes two bugs in processing of connection-Requests in
v{4,6}_conn_request:
1. Due to using the variable `reset_code', the Reset code generated
internally by dccp_parse_options() is overwritten with the
initialised value ("Too Busy") of reset_code, which is not what is
intended.
2. When receiving a connection-Request on a multicast or broadcast
address, no Reset should be generated, to avoid storms of such
packets. Instead of jumping to the `drop' label, the
v{4,6}_conn_request functions now return 0. Below is why in my
understanding this is correct:
When the conn_request function returns < 0, then the caller,
dccp_rcv_state_process(), returns 1. In all instances where
dccp_rcv_state_process is called (dccp_v4_do_rcv, dccp_v6_do_rcv,
and dccp_child_process), a return value of != 0 from
dccp_rcv_state_process() means that a Reset is generated.
If on the other hand the conn_request function returns 0, the
packet is discarded and no Reset is generated.
Note: There may be a related problem when sending the Response, due to
the following.
if (dccp_v6_send_response(sk, req, NULL))
goto drop_and_free;
/* ... */
drop_and_free:
return -1;
In this case, if send_response fails due to transmission errors, the
next thing that is generated is a Reset with a code "Too Busy". I
haven't been able to conjure up such a condition, but it might be good
to change the behaviour here also (not done by this patch).
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c
index 2312b9f..44f6e17 100644
--- a/net/dccp/ipv4.c
+++ b/net/dccp/ipv4.c
@@ -568,17 +568,14 @@
struct dccp_request_sock *dreq;
const __be32 service = dccp_hdr_request(skb)->dccph_req_service;
struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
- __u8 reset_code = DCCP_RESET_CODE_TOO_BUSY;
/* Never answer to DCCP_PKT_REQUESTs send to broadcast or multicast */
if (((struct rtable *)skb->dst)->rt_flags &
- (RTCF_BROADCAST | RTCF_MULTICAST)) {
- reset_code = DCCP_RESET_CODE_NO_CONNECTION;
- goto drop;
- }
+ (RTCF_BROADCAST | RTCF_MULTICAST))
+ return 0; /* discard, don't send a reset here */
if (dccp_bad_service_code(sk, service)) {
- reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE;
+ dcb->dccpd_reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE;
goto drop;
}
/*
@@ -586,6 +583,7 @@
* limitations, they conserve resources and peer is
* evidently real one.
*/
+ dcb->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
if (inet_csk_reqsk_queue_is_full(sk))
goto drop;
@@ -638,7 +636,6 @@
reqsk_free(req);
drop:
DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
- dcb->dccpd_reset_code = reset_code;
return -1;
}