[DCCP]: Set TX Queue Length Bounds via Sysctl
Previously the transmit queue was unbounded.
This patch:
* puts a limit on transmit queue length
and sends back EAGAIN if the buffer is full
* sets the TX queue length to a sensible default
* implements tx buffer sysctls for DCCP
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
diff --git a/net/dccp/dccp.h b/net/dccp/dccp.h
index 33d86f5..3a94625 100644
--- a/net/dccp/dccp.h
+++ b/net/dccp/dccp.h
@@ -87,6 +87,7 @@
extern int sysctl_dccp_feat_ack_ratio;
extern int sysctl_dccp_feat_send_ack_vector;
extern int sysctl_dccp_feat_send_ndp_count;
+extern int sysctl_dccp_tx_qlen;
/* is seq1 < seq2 ? */
static inline int before48(const u64 seq1, const u64 seq2)
diff --git a/net/dccp/proto.c b/net/dccp/proto.c
index 0225bda..a7f345c 100644
--- a/net/dccp/proto.c
+++ b/net/dccp/proto.c
@@ -52,6 +52,9 @@
EXPORT_SYMBOL_GPL(dccp_hashinfo);
+/* the maximum queue length for tx in packets. 0 is no limit */
+int sysctl_dccp_tx_qlen __read_mostly = 5;
+
void dccp_set_state(struct sock *sk, const int state)
{
const int oldstate = sk->sk_state;
@@ -645,6 +648,13 @@
return -EMSGSIZE;
lock_sock(sk);
+
+ if (sysctl_dccp_tx_qlen &&
+ (sk->sk_write_queue.qlen >= sysctl_dccp_tx_qlen)) {
+ rc = -EAGAIN;
+ goto out_release;
+ }
+
timeo = sock_sndtimeo(sk, noblock);
/*