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authorXin Long <lucien.xin@gmail.com>2018-06-28 15:31:00 +0800
committerDavid S. Miller <davem@davemloft.net>2018-06-29 22:20:55 +0900
commitb0e9a2fe3ff971950833bc0ffc383babd9443bc4 (patch)
tree05d1ad617d3fc18a8030eddaf6dadc1f8aa9a5f1 /net/sctp
parent23c94d63a7e395c5706f7d9edde1ff839b050c5f (diff)
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sctp: add support for SCTP_REUSE_PORT sockopt
This feature is actually already supported by sk->sk_reuse which can be set by socket level opt SO_REUSEADDR. But it's not working exactly as RFC6458 demands in section 8.1.27, like: - This option only supports one-to-one style SCTP sockets - This socket option must not be used after calling bind() or sctp_bindx(). Besides, SCTP_REUSE_PORT sockopt should be provided for user's programs. Otherwise, the programs with SCTP_REUSE_PORT from other systems will not work in linux. To separate it from the socket level version, this patch adds 'reuse' in sctp_sock and it works pretty much as sk->sk_reuse, but with some extra setup limitations that are needed when it is being enabled. "It should be noted that the behavior of the socket-level socket option to reuse ports and/or addresses for SCTP sockets is unspecified", so it leaves SO_REUSEADDR as is for the compatibility. Note that the name SCTP_REUSE_PORT is somewhat confusing, as its functionality is nearly identical to SO_REUSEADDR, but with some extra restrictions. Here it uses 'reuse' in sctp_sock instead of 'reuseport'. As for sk->sk_reuseport support for SCTP, it will be added in another patch. Thanks to Neil to make this clear. v1->v2: - add sctp_sk->reuse to separate it from the socket level version. v2->v3: - improve changelog according to Marcelo's suggestion. Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sctp')
-rw-r--r--net/sctp/socket.c62
1 files changed, 55 insertions, 7 deletions
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 0e91e83eea5a..bf11f9cacb63 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -4170,6 +4170,28 @@ out:
return retval;
}
+static int sctp_setsockopt_reuse_port(struct sock *sk, char __user *optval,
+ unsigned int optlen)
+{
+ int val;
+
+ if (!sctp_style(sk, TCP))
+ return -EOPNOTSUPP;
+
+ if (sctp_sk(sk)->ep->base.bind_addr.port)
+ return -EFAULT;
+
+ if (optlen < sizeof(int))
+ return -EINVAL;
+
+ if (get_user(val, (int __user *)optval))
+ return -EFAULT;
+
+ sctp_sk(sk)->reuse = !!val;
+
+ return 0;
+}
+
/* API 6.2 setsockopt(), getsockopt()
*
* Applications use setsockopt() and getsockopt() to set or retrieve
@@ -4364,6 +4386,9 @@ static int sctp_setsockopt(struct sock *sk, int level, int optname,
retval = sctp_setsockopt_interleaving_supported(sk, optval,
optlen);
break;
+ case SCTP_REUSE_PORT:
+ retval = sctp_setsockopt_reuse_port(sk, optval, optlen);
+ break;
default:
retval = -ENOPROTOOPT;
break;
@@ -7197,6 +7222,26 @@ out:
return retval;
}
+static int sctp_getsockopt_reuse_port(struct sock *sk, int len,
+ char __user *optval,
+ int __user *optlen)
+{
+ int val;
+
+ if (len < sizeof(int))
+ return -EINVAL;
+
+ len = sizeof(int);
+ val = sctp_sk(sk)->reuse;
+ if (put_user(len, optlen))
+ return -EFAULT;
+
+ if (copy_to_user(optval, &val, len))
+ return -EFAULT;
+
+ return 0;
+}
+
static int sctp_getsockopt(struct sock *sk, int level, int optname,
char __user *optval, int __user *optlen)
{
@@ -7392,6 +7437,9 @@ static int sctp_getsockopt(struct sock *sk, int level, int optname,
retval = sctp_getsockopt_interleaving_supported(sk, len, optval,
optlen);
break;
+ case SCTP_REUSE_PORT:
+ retval = sctp_getsockopt_reuse_port(sk, len, optval, optlen);
+ break;
default:
retval = -ENOPROTOOPT;
break;
@@ -7429,6 +7477,7 @@ static struct sctp_bind_bucket *sctp_bucket_create(
static long sctp_get_port_local(struct sock *sk, union sctp_addr *addr)
{
+ bool reuse = (sk->sk_reuse || sctp_sk(sk)->reuse);
struct sctp_bind_hashbucket *head; /* hash list */
struct sctp_bind_bucket *pp;
unsigned short snum;
@@ -7501,13 +7550,11 @@ pp_found:
* used by other socket (pp->owner not empty); that other
* socket is going to be sk2.
*/
- int reuse = sk->sk_reuse;
struct sock *sk2;
pr_debug("%s: found a possible match\n", __func__);
- if (pp->fastreuse && sk->sk_reuse &&
- sk->sk_state != SCTP_SS_LISTENING)
+ if (pp->fastreuse && reuse && sk->sk_state != SCTP_SS_LISTENING)
goto success;
/* Run through the list of sockets bound to the port
@@ -7525,7 +7572,7 @@ pp_found:
ep2 = sctp_sk(sk2)->ep;
if (sk == sk2 ||
- (reuse && sk2->sk_reuse &&
+ (reuse && (sk2->sk_reuse || sctp_sk(sk2)->reuse) &&
sk2->sk_state != SCTP_SS_LISTENING))
continue;
@@ -7549,12 +7596,12 @@ pp_not_found:
* SO_REUSEADDR on this socket -sk-).
*/
if (hlist_empty(&pp->owner)) {
- if (sk->sk_reuse && sk->sk_state != SCTP_SS_LISTENING)
+ if (reuse && sk->sk_state != SCTP_SS_LISTENING)
pp->fastreuse = 1;
else
pp->fastreuse = 0;
} else if (pp->fastreuse &&
- (!sk->sk_reuse || sk->sk_state == SCTP_SS_LISTENING))
+ (!reuse || sk->sk_state == SCTP_SS_LISTENING))
pp->fastreuse = 0;
/* We are set, so fill up all the data in the hash table
@@ -7685,7 +7732,7 @@ int sctp_inet_listen(struct socket *sock, int backlog)
err = 0;
sctp_unhash_endpoint(ep);
sk->sk_state = SCTP_SS_CLOSED;
- if (sk->sk_reuse)
+ if (sk->sk_reuse || sctp_sk(sk)->reuse)
sctp_sk(sk)->bind_hash->fastreuse = 1;
goto out;
}
@@ -8550,6 +8597,7 @@ void sctp_copy_sock(struct sock *newsk, struct sock *sk,
newsk->sk_no_check_tx = sk->sk_no_check_tx;
newsk->sk_no_check_rx = sk->sk_no_check_rx;
newsk->sk_reuse = sk->sk_reuse;
+ sctp_sk(newsk)->reuse = sp->reuse;
newsk->sk_shutdown = sk->sk_shutdown;
newsk->sk_destruct = sctp_destruct_sock;