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authorDavid Laight <David.Laight@ACULAB.COM>2023-12-06 13:44:20 +0000
committerJakub Kicinski <kuba@kernel.org>2023-12-08 10:44:42 -0800
commitd9f28735af8781d9c8c6c406c2a102090644133d (patch)
treeaff37910520f90b4c192c41a00fbde053c2d01e8 /net/ipv4
parent36b0bdb6d330fe0546fc7f97d93e8cfa57421ad9 (diff)
Use READ/WRITE_ONCE() for IP local_port_range.
Commit 227b60f5102cd added a seqlock to ensure that the low and high port numbers were always updated together. This is overkill because the two 16bit port numbers can be held in a u32 and read/written in a single instruction. More recently 91d0b78c5177f added support for finer per-socket limits. The user-supplied value is 'high << 16 | low' but they are held separately and the socket options protected by the socket lock. Use a u32 containing 'high << 16 | low' for both the 'net' and 'sk' fields and use READ_ONCE()/WRITE_ONCE() to ensure both values are always updated together. Change (the now trival) inet_get_local_port_range() to a static inline to optimise the calling code. (In particular avoiding returning integers by reference.) Signed-off-by: David Laight <david.laight@aculab.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: David Ahern <dsahern@kernel.org> Acked-by: Mat Martineau <martineau@kernel.org> Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://lore.kernel.org/r/4e505d4198e946a8be03fb1b4c3072b0@AcuMS.aculab.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/ipv4')
-rw-r--r--net/ipv4/af_inet.c4
-rw-r--r--net/ipv4/inet_connection_sock.c29
-rw-r--r--net/ipv4/ip_sockglue.c33
-rw-r--r--net/ipv4/sysctl_net_ipv4.c18
4 files changed, 34 insertions, 50 deletions
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index fb81de10d332..fbeacf04dbf3 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -1847,9 +1847,7 @@ static __net_init int inet_init_net(struct net *net)
/*
* Set defaults for local port range
*/
- seqlock_init(&net->ipv4.ip_local_ports.lock);
- net->ipv4.ip_local_ports.range[0] = 32768;
- net->ipv4.ip_local_ports.range[1] = 60999;
+ net->ipv4.ip_local_ports.range = 60999u << 16 | 32768u;
seqlock_init(&net->ipv4.ping_group_range.lock);
/*
diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index 394a498c2823..70be0f6fe879 100644
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -117,34 +117,25 @@ bool inet_rcv_saddr_any(const struct sock *sk)
return !sk->sk_rcv_saddr;
}
-void inet_get_local_port_range(const struct net *net, int *low, int *high)
-{
- unsigned int seq;
-
- do {
- seq = read_seqbegin(&net->ipv4.ip_local_ports.lock);
-
- *low = net->ipv4.ip_local_ports.range[0];
- *high = net->ipv4.ip_local_ports.range[1];
- } while (read_seqretry(&net->ipv4.ip_local_ports.lock, seq));
-}
-EXPORT_SYMBOL(inet_get_local_port_range);
-
void inet_sk_get_local_port_range(const struct sock *sk, int *low, int *high)
{
const struct inet_sock *inet = inet_sk(sk);
const struct net *net = sock_net(sk);
int lo, hi, sk_lo, sk_hi;
+ u32 sk_range;
inet_get_local_port_range(net, &lo, &hi);
- sk_lo = inet->local_port_range.lo;
- sk_hi = inet->local_port_range.hi;
+ sk_range = READ_ONCE(inet->local_port_range);
+ if (unlikely(sk_range)) {
+ sk_lo = sk_range & 0xffff;
+ sk_hi = sk_range >> 16;
- if (unlikely(lo <= sk_lo && sk_lo <= hi))
- lo = sk_lo;
- if (unlikely(lo <= sk_hi && sk_hi <= hi))
- hi = sk_hi;
+ if (lo <= sk_lo && sk_lo <= hi)
+ lo = sk_lo;
+ if (lo <= sk_hi && sk_hi <= hi)
+ hi = sk_hi;
+ }
*low = lo;
*high = hi;
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 2efc53526a38..d7d13940774e 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -1055,6 +1055,19 @@ int do_ip_setsockopt(struct sock *sk, int level, int optname,
case IP_TOS: /* This sets both TOS and Precedence */
ip_sock_set_tos(sk, val);
return 0;
+ case IP_LOCAL_PORT_RANGE:
+ {
+ u16 lo = val;
+ u16 hi = val >> 16;
+
+ if (optlen != sizeof(u32))
+ return -EINVAL;
+ if (lo != 0 && hi != 0 && lo > hi)
+ return -EINVAL;
+
+ WRITE_ONCE(inet->local_port_range, val);
+ return 0;
+ }
}
err = 0;
@@ -1332,20 +1345,6 @@ int do_ip_setsockopt(struct sock *sk, int level, int optname,
err = xfrm_user_policy(sk, optname, optval, optlen);
break;
- case IP_LOCAL_PORT_RANGE:
- {
- const __u16 lo = val;
- const __u16 hi = val >> 16;
-
- if (optlen != sizeof(__u32))
- goto e_inval;
- if (lo != 0 && hi != 0 && lo > hi)
- goto e_inval;
-
- inet->local_port_range.lo = lo;
- inet->local_port_range.hi = hi;
- break;
- }
default:
err = -ENOPROTOOPT;
break;
@@ -1692,6 +1691,9 @@ int do_ip_getsockopt(struct sock *sk, int level, int optname,
return -EFAULT;
return 0;
}
+ case IP_LOCAL_PORT_RANGE:
+ val = READ_ONCE(inet->local_port_range);
+ goto copyval;
}
if (needs_rtnl)
@@ -1721,9 +1723,6 @@ int do_ip_getsockopt(struct sock *sk, int level, int optname,
else
err = ip_get_mcast_msfilter(sk, optval, optlen, len);
goto out;
- case IP_LOCAL_PORT_RANGE:
- val = inet->local_port_range.hi << 16 | inet->local_port_range.lo;
- break;
case IP_PROTOCOL:
val = inet_sk(sk)->inet_num;
break;
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index f63a545a7374..7e4f16a7dcc1 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -50,26 +50,22 @@ static int tcp_plb_max_cong_thresh = 256;
static int sysctl_tcp_low_latency __read_mostly;
/* Update system visible IP port range */
-static void set_local_port_range(struct net *net, int range[2])
+static void set_local_port_range(struct net *net, unsigned int low, unsigned int high)
{
- bool same_parity = !((range[0] ^ range[1]) & 1);
+ bool same_parity = !((low ^ high) & 1);
- write_seqlock_bh(&net->ipv4.ip_local_ports.lock);
if (same_parity && !net->ipv4.ip_local_ports.warned) {
net->ipv4.ip_local_ports.warned = true;
pr_err_ratelimited("ip_local_port_range: prefer different parity for start/end values.\n");
}
- net->ipv4.ip_local_ports.range[0] = range[0];
- net->ipv4.ip_local_ports.range[1] = range[1];
- write_sequnlock_bh(&net->ipv4.ip_local_ports.lock);
+ WRITE_ONCE(net->ipv4.ip_local_ports.range, high << 16 | low);
}
/* Validate changes from /proc interface. */
static int ipv4_local_port_range(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
- struct net *net =
- container_of(table->data, struct net, ipv4.ip_local_ports.range);
+ struct net *net = table->data;
int ret;
int range[2];
struct ctl_table tmp = {
@@ -93,7 +89,7 @@ static int ipv4_local_port_range(struct ctl_table *table, int write,
(range[0] < READ_ONCE(net->ipv4.sysctl_ip_prot_sock)))
ret = -EINVAL;
else
- set_local_port_range(net, range);
+ set_local_port_range(net, range[0], range[1]);
}
return ret;
@@ -733,8 +729,8 @@ static struct ctl_table ipv4_net_table[] = {
},
{
.procname = "ip_local_port_range",
- .maxlen = sizeof(init_net.ipv4.ip_local_ports.range),
- .data = &init_net.ipv4.ip_local_ports.range,
+ .maxlen = 0,
+ .data = &init_net,
.mode = 0644,
.proc_handler = ipv4_local_port_range,
},