[RFC PATCH 25/39] sctp: resolve numeric ranges from the current namespace

[wen . yang]

From: Wen Yang <wen.yang@xxxxxxxxx>

Read sibling SCTP limits from the current namespace on each call.

Suggested-by: Joel Granados <joel.granados@xxxxxxxxxx>
Signed-off-by: Wen Yang <wen.yang@xxxxxxxxx>
---
 net/sctp/sysctl.c | 147 +++++++++++++++++++++++-----------------------
 1 file changed, 72 insertions(+), 75 deletions(-)

diff --git a/net/sctp/sysctl.c b/net/sctp/sysctl.c
index 59c6f22337ea..ed296f568887 100644
--- a/net/sctp/sysctl.c
+++ b/net/sctp/sysctl.c
@@ -24,25 +24,6 @@
 #include <net/sctp/structs.h>
 #include <net/sctp/sctp.h>
 #include <linux/sysctl.h>
-#include <linux/limits.h>
-
-static int timer_max = 86400000; /* ms in one day */
-static int sack_timer_min = 1;
-static int sack_timer_max = 500;
-static int addr_scope_max = SCTP_SCOPE_POLICY_MAX;
-static int rwnd_scale_max = 16;
-static int rto_alpha_min = 0;
-static int rto_beta_min = 0;
-static int rto_alpha_max = 1000;
-static int rto_beta_max = 1000;
-static int pf_expose_max = SCTP_PF_EXPOSE_MAX;
-static int ps_retrans_max = SCTP_PS_RETRANS_MAX;
-static int udp_port_max = 65535;
-
-static unsigned long max_autoclose_min = 0;
-static unsigned long max_autoclose_max =
-	(MAX_SCHEDULE_TIMEOUT / HZ > UINT_MAX)
-	? UINT_MAX : MAX_SCHEDULE_TIMEOUT / HZ;
 
 static int proc_sctp_do_hmac_alg(const struct ctl_table *ctl, int write,
 				 void *buffer, size_t *lenp, loff_t *ppos);
@@ -50,6 +31,26 @@ static int proc_sctp_do_rto_min(const struct ctl_table *ctl, int write,
 				void *buffer, size_t *lenp, loff_t *ppos);
 static int proc_sctp_do_rto_max(const struct ctl_table *ctl, int write, void *buffer,
 				size_t *lenp, loff_t *ppos);
+static int proc_sctp_do_pf_retrans(const struct ctl_table *ctl, int write,
+				   void *buffer, size_t *lenp, loff_t *ppos)
+{
+	struct net *net = container_of(ctl->data, struct net, sctp.pf_retrans);
+	struct ctl_table tmp = *ctl;
+
+	tmp.max = (unsigned long)READ_ONCE(net->sctp.ps_retrans);
+	return proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
+}
+
+static int proc_sctp_do_ps_retrans(const struct ctl_table *ctl, int write,
+				   void *buffer, size_t *lenp, loff_t *ppos)
+{
+	struct net *net = container_of(ctl->data, struct net, sctp.ps_retrans);
+	struct ctl_table tmp = *ctl;
+
+	tmp.min = (unsigned long)READ_ONCE(net->sctp.pf_retrans);
+	return proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
+}
+
 static int proc_sctp_do_udp_port(const struct ctl_table *ctl, int write, void *buffer,
 				 size_t *lenp, loff_t *ppos);
 static int proc_sctp_do_alpha_beta(const struct ctl_table *ctl, int write,
@@ -65,7 +66,7 @@ static struct ctl_table sctp_table[] = {
 		.data		= &sysctl_sctp_mem,
 		.maxlen		= sizeof(sysctl_sctp_mem),
 		.mode		= 0644,
-		.proc_handler	= proc_doulongvec_minmax
+		.proc_handler	= proc_doulongvec_minmax,
 		.min		= 0,
 		.max		= ULONG_MAX,
 	},
@@ -102,8 +103,8 @@ static const struct ctl_table sctp_net_table[] = {
 		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
 		.proc_handler	= proc_sctp_do_rto_min,
-		.extra1         = SYSCTL_ONE,
-		.extra2         = &init_net.sctp.rto_max
+		.min		= 1,
+		.max		= UINT_MAX,
 	},
 	[SCTP_RTO_MAX_IDX] =  {
 		.procname	= "rto_max",
@@ -111,26 +112,26 @@ static const struct ctl_table sctp_net_table[] = {
 		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
 		.proc_handler	= proc_sctp_do_rto_max,
-		.extra1         = &init_net.sctp.rto_min,
-		.extra2         = &timer_max
+		.min		= 0,
+		.max		= 86400000,
 	},
 	[SCTP_PF_RETRANS_IDX] = {
 		.procname	= "pf_retrans",
 		.data		= &init_net.sctp.pf_retrans,
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= &init_net.sctp.ps_retrans,
+		.proc_handler	= proc_sctp_do_pf_retrans,
+		.min		= 0,
+		.max		= INT_MAX,
 	},
 	[SCTP_PS_RETRANS_IDX] = {
 		.procname	= "ps_retrans",
 		.data		= &init_net.sctp.ps_retrans,
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &init_net.sctp.pf_retrans,
-		.extra2		= &ps_retrans_max,
+		.proc_handler	= proc_sctp_do_ps_retrans,
+		.min		= (unsigned long)INT_MIN,
+		.max		= SCTP_PS_RETRANS_MAX,
 	},
 	{
 		.procname	= "rto_initial",
@@ -138,8 +139,8 @@ static const struct ctl_table sctp_net_table[] = {
 		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1         = SYSCTL_ONE,
-		.extra2         = &timer_max
+		.min		= 1,
+		.max		= 86400000
 	},
 	{
 		.procname	= "rto_alpha_exp_divisor",
@@ -147,8 +148,8 @@ static const struct ctl_table sctp_net_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_sctp_do_alpha_beta,
-		.extra1		= &rto_alpha_min,
-		.extra2		= &rto_alpha_max,
+		.min		= 0,
+		.max		= 1000,
 	},
 	{
 		.procname	= "rto_beta_exp_divisor",
@@ -156,8 +157,8 @@ static const struct ctl_table sctp_net_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_sctp_do_alpha_beta,
-		.extra1		= &rto_beta_min,
-		.extra2		= &rto_beta_max,
+		.min		= 0,
+		.max		= 1000,
 	},
 	{
 		.procname	= "max_burst",
@@ -165,8 +166,8 @@ static const struct ctl_table sctp_net_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= SYSCTL_INT_MAX,
+		.min		= 0,
+		.max		= INT_MAX,
 	},
 	{
 		.procname	= "cookie_preserve_enable",
@@ -188,8 +189,8 @@ static const struct ctl_table sctp_net_table[] = {
 		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1         = SYSCTL_ONE,
-		.extra2         = &timer_max
+		.min		= 1,
+		.max		= 86400000
 	},
 	{
 		.procname	= "sack_timeout",
@@ -197,8 +198,8 @@ static const struct ctl_table sctp_net_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1         = &sack_timer_min,
-		.extra2         = &sack_timer_max,
+		.min		= 1,
+		.max		= 500,
 	},
 	{
 		.procname	= "hb_interval",
@@ -206,8 +207,8 @@ static const struct ctl_table sctp_net_table[] = {
 		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1         = SYSCTL_ONE,
-		.extra2         = &timer_max
+		.min		= 1,
+		.max		= 86400000
 	},
 	{
 		.procname	= "association_max_retrans",
@@ -215,8 +216,8 @@ static const struct ctl_table sctp_net_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= SYSCTL_ONE,
-		.extra2		= SYSCTL_INT_MAX,
+		.min		= 1,
+		.max		= INT_MAX,
 	},
 	{
 		.procname	= "path_max_retrans",
@@ -224,8 +225,8 @@ static const struct ctl_table sctp_net_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= SYSCTL_ONE,
-		.extra2		= SYSCTL_INT_MAX,
+		.min		= 1,
+		.max		= INT_MAX,
 	},
 	{
 		.procname	= "max_init_retransmits",
@@ -233,8 +234,8 @@ static const struct ctl_table sctp_net_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= SYSCTL_ONE,
-		.extra2		= SYSCTL_INT_MAX,
+		.min		= 1,
+		.max		= INT_MAX,
 	},
 	{
 		.procname	= "sndbuf_policy",
@@ -319,8 +320,8 @@ static const struct ctl_table sctp_net_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_sctp_do_udp_port,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= &udp_port_max,
+		.min		= 0,
+		.max		= 65535,
 	},
 	{
 		.procname	= "encap_port",
@@ -328,8 +329,8 @@ static const struct ctl_table sctp_net_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= &udp_port_max,
+		.min		= 0,
+		.max		= 65535,
 	},
 	{
 		.procname	= "addr_scope_policy",
@@ -337,8 +338,8 @@ static const struct ctl_table sctp_net_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= &addr_scope_max,
+		.min		= 0,
+		.max		= SCTP_SCOPE_POLICY_MAX,
 	},
 	{
 		.procname	= "rwnd_update_shift",
@@ -346,8 +347,8 @@ static const struct ctl_table sctp_net_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= &proc_dointvec_minmax,
-		.extra1		= SYSCTL_ONE,
-		.extra2		= &rwnd_scale_max,
+		.min		= 1,
+		.max		= 16,
 	},
 	{
 		.procname	= "max_autoclose",
@@ -355,8 +356,9 @@ static const struct ctl_table sctp_net_table[] = {
 		.maxlen		= sizeof(unsigned long),
 		.mode		= 0644,
 		.proc_handler	= &proc_doulongvec_minmax,
-		.extra1		= &max_autoclose_min,
-		.extra2		= &max_autoclose_max,
+		.min		= 0,
+		.max		= (MAX_SCHEDULE_TIMEOUT / HZ > UINT_MAX)
+				  ? UINT_MAX : MAX_SCHEDULE_TIMEOUT / HZ,
 	},
 #ifdef CONFIG_NET_L3_MASTER_DEV
 	{
@@ -365,8 +367,8 @@ static const struct ctl_table sctp_net_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= SYSCTL_ONE,
+		.min		= 0,
+		.max		= 1,
 	},
 #endif
 	{
@@ -382,8 +384,8 @@ static const struct ctl_table sctp_net_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= &pf_expose_max,
+		.min		= 0,
+		.max		= SCTP_PF_EXPOSE_MAX,
 	},
 };
 
@@ -426,8 +428,8 @@ static int proc_sctp_do_rto_min(const struct ctl_table *ctl, int write,
 				void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct net *net = container_of(ctl->data, struct net, sctp.rto_min);
-	unsigned int min = *(unsigned int *) ctl->extra1;
-	unsigned int max = *(unsigned int *) ctl->extra2;
+	unsigned int min = ctl->min;
+	unsigned int max = READ_ONCE(net->sctp.rto_max);
 	struct ctl_table tbl;
 	int ret, new_value;
 
@@ -454,8 +456,8 @@ static int proc_sctp_do_rto_max(const struct ctl_table *ctl, int write,
 				void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct net *net = container_of(ctl->data, struct net, sctp.rto_max);
-	unsigned int min = *(unsigned int *) ctl->extra1;
-	unsigned int max = *(unsigned int *) ctl->extra2;
+	unsigned int min = READ_ONCE(net->sctp.rto_min);
+	unsigned int max = ctl->max;
 	struct ctl_table tbl;
 	int ret, new_value;
 
@@ -523,8 +525,8 @@ static int proc_sctp_do_udp_port(const struct ctl_table *ctl, int write,
 				 void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct net *net = container_of(ctl->data, struct net, sctp.udp_port);
-	unsigned int min = *(unsigned int *)ctl->extra1;
-	unsigned int max = *(unsigned int *)ctl->extra2;
+	unsigned int min = ctl->min;
+	unsigned int max = ctl->max;
 	struct ctl_table tbl;
 	int ret, new_value;
 
@@ -602,11 +604,6 @@ int sctp_sysctl_net_register(struct net *net)
 	for (i = 0; i < table_size; i++)
 		table[i].data += (char *)(&net->sctp) - (char *)&init_net.sctp;
 
-	table[SCTP_RTO_MIN_IDX].extra2 = &net->sctp.rto_max;
-	table[SCTP_RTO_MAX_IDX].extra1 = &net->sctp.rto_min;
-	table[SCTP_PF_RETRANS_IDX].extra2 = &net->sctp.ps_retrans;
-	table[SCTP_PS_RETRANS_IDX].extra1 = &net->sctp.pf_retrans;
-
 	net->sctp.sysctl_header = register_net_sysctl_sz(net, "net/sctp",
 							 table, table_size);
 	if (net->sctp.sysctl_header == NULL) {
-- 
2.25.1