From Wang Weidong <wangweidong1@xxxxxxxxxx>
On 2013/12/7 20:43, Daniel Borkmann wrote:
On 12/07/2013 08:17 AM, Wang Weidong wrote:
rto_min should be smaller than rto_max while rto_max should be larger
than rto_min. Add two proc_handler for the checking. Add the check in
sctp_setsockopt_rtoinfo.
Suggested-by: Vlad Yasevich <vyasevich@xxxxxxxxx>
Signed-off-by: Wang Weidong <wangweidong1@xxxxxxxxxx>
---
Thanks Wang, also for your second patch.
Second one looks good to me, thanks for the cleanup!
I was wondering where 86400000 comes from? Looking through the git
history didn't give much clues and the RFC4960 neither. Clearly,
section 15 of RFC4960 *recommends* as initial values ...
RTO.Initial - 3 seconds
RTO.Min - 1 second
RTO.Max - 60 seconds
... which we have as constants in [1] and are assigned to globals
initially in [2,3] with those recommended values. That's all good.
But still [not *directly* related to your patch though], where does
86400000 come from? I expect that's for the max SCTP heartbeat
interval or max cookie lifetime?
Sorry, I don't know 86400000 come form as well.
Hence, timer_max is used in multiple contexts for timers here,
which seems a bit confusing. If it really makes sense to have such
a huge RTO max though, then it at least needs a comment explaining
so. ;)
Wang, just a minor nitpick, I would much rather name them those
defines like ...
SCTP_RTO_MIN_LIMIT
SCTP_RTO_MAX_LIMIT
... just so that we have recommended and upper limit constants with
a more clear naming as obviously SCTP_ONE doesn't make much sense.
[1] include/net/sctp/constants.h +269
[2] include/net/netns/sctp.h +39
[3] net/sctp/protocol.c +1169
More below ...
include/net/sctp/constants.h | 3 ++
net/sctp/socket.c | 5 +++
net/sctp/sysctl.c | 73 ++++++++++++++++++++++++++++++++++++++++----
3 files changed, 75 insertions(+), 6 deletions(-)
diff --git a/include/net/sctp/constants.h b/include/net/sctp/constants.h
index 2f0a565..d276978 100644
--- a/include/net/sctp/constants.h
+++ b/include/net/sctp/constants.h
@@ -279,6 +279,9 @@ enum { SCTP_MAX_GABS = 16 };
#define SCTP_RTO_ALPHA 3 /* 1/8 when converted to right shifts. */
#define SCTP_RTO_BETA 2 /* 1/4 when converted to right shifts. */
+#define SCTP_ONE 1 /* 1 ms */
+#define SCTP_TIMER_MAX 86400000 /* ms in one day */
+
/* Maximum number of new data packets that can be sent in a burst. */
#define SCTP_DEFAULT_MAX_BURST 4
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 72046b9..13411ad 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -2818,6 +2818,11 @@ static int sctp_setsockopt_rtoinfo(struct sock *sk, char __user *optval, unsigne
if (copy_from_user(&rtoinfo, optval, optlen))
return -EFAULT;
+ if (rtoinfo.srto_min < SCTP_ONE ||
+ rtoinfo.srto_max > SCTP_TIMER_MAX ||
+ rtoinfo.srto_max < rtoinfo.srto_min)
+ return -EINVAL;
+
asoc = sctp_id2assoc(sk, rtoinfo.srto_assoc_id);
/* Set the values to the specific association */
diff --git a/net/sctp/sysctl.c b/net/sctp/sysctl.c
index 6b36561..33c56c6 100644
--- a/net/sctp/sysctl.c
+++ b/net/sctp/sysctl.c
@@ -40,8 +40,8 @@
#include <linux/sysctl.h>
static int zero = 0;
-static int one = 1;
-static int timer_max = 86400000; /* ms in one day */
+static int one = SCTP_ONE;
+static int timer_max = SCTP_TIMER_MAX;
So here, I'd do something like this ...
static int one = 1; (leaving this as is)
static int timer_max = 86400000; /* Max 1 day for HB interval, cookie life-time*/
static int rto_timer_min = SCTP_RTO_MIN_LIMIT;
static int rto_timer_max = SCTP_RTO_MAX_LIMIT;
... so that we have sack_timer_{min,max} and rto_timer_{min,max}.
Opinions, thoughts?
Agree. Your Opinions is very good.
Thanks a lot, you help me so much. I think I should wait for the
explanation of the 86400000, then send the v6.
Regards.
Wang
static int int_max = INT_MAX;
static int sack_timer_min = 1;
static int sack_timer_max = 500;
@@ -61,6 +61,13 @@ static int proc_sctp_do_hmac_alg(struct ctl_table *ctl,
void __user *buffer, size_t *lenp,
loff_t *ppos);
+static int proc_sctp_do_rto_min(struct ctl_table *ctl, int write,
+ void __user *buffer, size_t *lenp,
+ loff_t *ppos);
+static int proc_sctp_do_rto_max(struct ctl_table *ctl, int write,
+ void __user *buffer, size_t *lenp,
+ loff_t *ppos);
+
static struct ctl_table sctp_table[] = {
{
.procname = "sctp_mem",
@@ -102,17 +109,17 @@ static struct ctl_table sctp_net_table[] = {
.data = &init_net.sctp.rto_min,
.maxlen = sizeof(unsigned int),
.mode = 0644,
- .proc_handler = proc_dointvec_minmax,
+ .proc_handler = proc_sctp_do_rto_min,
.extra1 = &one,
- .extra2 = &timer_max
+ .extra2 = &init_net.sctp.rto_max
},
{
.procname = "rto_max",
.data = &init_net.sctp.rto_max,
.maxlen = sizeof(unsigned int),
.mode = 0644,
- .proc_handler = proc_dointvec_minmax,
- .extra1 = &one,
+ .proc_handler = proc_sctp_do_rto_max,
+ .extra1 = &init_net.sctp.rto_min,
.extra2 = &timer_max
},
{
@@ -342,6 +349,60 @@ static int proc_sctp_do_hmac_alg(struct ctl_table *ctl,
return ret;
}
+static int proc_sctp_do_rto_min(struct ctl_table *ctl, int write,
+ void __user*buffer, size_t *lenp,
+ loff_t *ppos)
+{
+ struct net *net = current->nsproxy->net_ns;
+ int new_value;
+ struct ctl_table tbl;
+ unsigned int min = *(unsigned int *) ctl->extra1;
+ unsigned int max = *(unsigned int *) ctl->extra2;
+ int ret;
+
+ memset(&tbl, 0, sizeof(struct ctl_table));
+ tbl.maxlen = sizeof(unsigned int);
+
+ if (write)
+ tbl.data = &new_value;
+ else
+ tbl.data = &net->sctp.rto_min;
+ ret = proc_dointvec(&tbl, write, buffer, lenp, ppos);
+ if (write) {
+ if (ret || new_value > max || new_value < min)
+ return -EINVAL;
+ net->sctp.rto_min = new_value;
+ }
+ return ret;
+}
+
+static int proc_sctp_do_rto_max(struct ctl_table *ctl, int write,
+ void __user*buffer, size_t *lenp,
+ loff_t *ppos)
+{
+ struct net *net = current->nsproxy->net_ns;
+ int new_value;
+ struct ctl_table tbl;
+ unsigned int min = *(unsigned int *) ctl->extra1;
+ unsigned int max = *(unsigned int *) ctl->extra2;
+ int ret;
+
+ memset(&tbl, 0, sizeof(struct ctl_table));
+ tbl.maxlen = sizeof(unsigned int);
+
+ if (write)
+ tbl.data = &new_value;
+ else
+ tbl.data = &net->sctp.rto_max;
+ ret = proc_dointvec(&tbl, write, buffer, lenp, ppos);
+ if (write) {
+ if (ret || new_value > max || new_value < min)
+ return -EINVAL;
+ net->sctp.rto_max = new_value;
+ }
+ return ret;
+}
+
int sctp_sysctl_net_register(struct net *net)
{
struct ctl_table *table;
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