Since packets with invalid cmsg parameters can be rejected by kernel there
is a need to allow applications to access information on available policies
and their respective cmsg parameters at runtime. This patch simplifies
maintaining compatibility between userspace applications and DCCP code.
Signed-off-by: Tomasz Grobelny <tomasz@xxxxxxxxxxxxxxxxxxxxxxx>
---
include/linux/dccp.h | 5 +++
net/dccp/dccp.h | 4 +++
net/dccp/proto.c | 2 +
net/dccp/qpolicy.c | 67 +++++++++++++++++++++++++++++++++++++++++++------
4 files changed, 69 insertions(+), 9 deletions(-)
diff --git a/include/linux/dccp.h b/include/linux/dccp.h
index 5c27e27..950ecd5 100644
--- a/include/linux/dccp.h
+++ b/include/linux/dccp.h
@@ -226,6 +226,11 @@ enum dccp_packet_dequeueing_policy {
#define DCCP_SOCKOPT_CCID_RX_INFO 128
#define DCCP_SOCKOPT_CCID_TX_INFO 192
+#define DCCP_SOCKOPT_QPOLICY_MIN 256
+#define DCCP_SOCKOPT_QPOLICY_AVAILABLE 256
+#define DCCP_SOCKOPT_QPOLICY_PARAMS 257
+#define DCCP_SOCKOPT_QPOLICY_MAX 512
+
/* maximum number of services provided on the same listening port */
#define DCCP_SERVICE_LIST_MAX_LEN 32
/* maximum number of CCID preferences that can be registered at one time */
diff --git a/net/dccp/dccp.h b/net/dccp/dccp.h
index c6e1a9c..1610807 100644
--- a/net/dccp/dccp.h
+++ b/net/dccp/dccp.h
@@ -223,6 +223,10 @@ extern bool dccp_qpolicy_full(struct sock *sk);
extern void dccp_qpolicy_drop(struct sock *sk, struct sk_buff *skb);
extern struct sk_buff *dccp_qpolicy_top(struct sock *sk);
extern struct sk_buff *dccp_qpolicy_pop(struct sock *sk);
+extern int dccp_qpolicy_getsockopt(struct sock *sk, int len,
+ int optname,
+ char __user *optval,
+ int __user *optlen);
/*
* TX Packet Output and TX Timers
diff --git a/net/dccp/proto.c b/net/dccp/proto.c
index bdc4126..c9596ff 100644
--- a/net/dccp/proto.c
+++ b/net/dccp/proto.c
@@ -669,6 +669,8 @@ static int do_dccp_getsockopt(struct sock *sk, int level, int optname,
case 192 ... 255:
return ccid_hc_tx_getsockopt(dp->dccps_hc_tx_ccid, sk, optname,
len, (u32 __user *)optval, optlen);
+ case DCCP_SOCKOPT_QPOLICY_MIN ... DCCP_SOCKOPT_QPOLICY_MAX:
+ return dccp_qpolicy_getsockopt(sk, len, optname, optval, optlen);
default:
return -ENOPROTOOPT;
}
diff --git a/net/dccp/qpolicy.c b/net/dccp/qpolicy.c
index 4270c7f..ba4f6a1 100644
--- a/net/dccp/qpolicy.c
+++ b/net/dccp/qpolicy.c
@@ -9,6 +9,7 @@
* modify it under the terms of the GNU General Public License v2
* as published by the Free Software Foundation.
*/
+#include <linux/dccp.h>
#include <asm/unaligned.h>
#include "dccp.h"
@@ -64,6 +65,28 @@ static bool qpolicy_prio_full(struct sock *sk)
return false;
}
+static int put_table(u32 *table, int psize, int len,
+ char __user *optval, int __user *optlen)
+{
+ if (len < psize)
+ return -EINVAL;
+ if (put_user(psize, optlen) || copy_to_user(optval, table, psize))
+ return -EFAULT;
+ return 0;
+}
+
+static int prio_params[] = {
+ DCCP_SCM_PRIORITY,
+};
+
+static int qpolicy_prio_getsockopt(struct sock *sk, int len, int optname,
+ char __user *optval, int __user *optlen)
+{
+ if (optname != DCCP_SOCKOPT_QPOLICY_PARAMS)
+ return -ENOPROTOOPT;
+ return put_table(prio_params, sizeof(prio_params), len, optval, optlen);
+}
+
/**
* struct dccp_qpolicy_operations - TX Packet Dequeueing Interface
* @push: add a new @skb with possibly a struct dccp_packet_info
@@ -71,20 +94,24 @@ static bool qpolicy_prio_full(struct sock *sk)
* @top: peeks at whatever the queueing policy defines as its top
*/
static struct dccp_qpolicy_operations {
- void (*push) (struct sock *sk, struct sk_buff *skb);
- bool (*full) (struct sock *sk);
- struct sk_buff* (*top) (struct sock *sk);
+ void (*push) (struct sock *sk, struct sk_buff *skb);
+ bool (*full) (struct sock *sk);
+ struct sk_buff* (*top) (struct sock *sk);
+ int (*getsockopt)(struct sock *sk, int len, int optname,
+ char __user *optval, int __user *optlen);
} qpol_table[DCCPQ_POLICY_MAX] = {
[DCCPQ_POLICY_SIMPLE] = {
- .push = qpolicy_simple_push,
- .full = qpolicy_simple_full,
- .top = qpolicy_simple_top,
+ .push = qpolicy_simple_push,
+ .full = qpolicy_simple_full,
+ .top = qpolicy_simple_top,
+ .getsockopt = NULL,
},
[DCCPQ_POLICY_PRIO] = {
- .push = qpolicy_simple_push,
- .full = qpolicy_prio_full,
- .top = qpolicy_prio_best_skb,
+ .push = qpolicy_simple_push,
+ .full = qpolicy_prio_full,
+ .top = qpolicy_prio_best_skb,
+ .getsockopt = qpolicy_prio_getsockopt,
},
};
@@ -125,3 +152,25 @@ struct sk_buff *dccp_qpolicy_pop(struct sock *sk)
skb_unlink(skb, &sk->sk_write_queue);
return skb;
}
+
+static int qpolicy_numbers[] = {
+ DCCPQ_POLICY_SIMPLE,
+ DCCPQ_POLICY_PRIO,
+};
+
+int dccp_qpolicy_getsockopt(struct sock *sk, int len, int optname,
+ char __user *optval, int __user *optlen)
+{
+ switch (optname) {
+ case DCCP_SOCKOPT_QPOLICY_AVAILABLE:
+ return put_table(qpolicy_numbers, sizeof(qpolicy_numbers),
+ len, optval, optlen);
+ default:
+ if ( qpol_table[dccp_sk(sk)->dccps_qpolicy].getsockopt != NULL)
+ return qpol_table[dccp_sk(sk)->dccps_qpolicy].getsockopt
+ (sk, len, optname, optval, optlen);
+ else
+ return -ENOPROTOOPT;
+ }
+ return 0;
+}
--
1.5.4.5
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