sctp: add SCTP_PLPMTUD_PROBE_INTERVAL sockopt for sock/asoc/transport

With this socket option, users can change probe_interval for
a transport, asoc or sock after it's created.

Note that if the change is for an asoc, also apply the change
to each transport in this asoc.
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/uapi/linux/sctp.h

@@ -141,6 +141,7 @@ typedef __s32 sctp_assoc_t;
 #define SCTP_EXPOSE_POTENTIALLY_FAILED_STATE	131
 #define SCTP_EXPOSE_PF_STATE	SCTP_EXPOSE_POTENTIALLY_FAILED_STATE
 #define SCTP_REMOTE_UDP_ENCAPS_PORT	132
+#define SCTP_PLPMTUD_PROBE_INTERVAL	133
 
 /* PR-SCTP policies */
 #define SCTP_PR_SCTP_NONE	0x0000
@@ -1213,4 +1214,11 @@ enum sctp_sched_type {
 	SCTP_SS_MAX = SCTP_SS_RR
 };
 
+/* Probe Interval socket option */
+struct sctp_probeinterval {
+	sctp_assoc_t spi_assoc_id;
+	struct sockaddr_storage spi_address;
+	__u32 spi_interval;
+};
+
 #endif /* _UAPI_SCTP_H */

net/sctp/socket.c

@@ -4481,6 +4481,58 @@ static int sctp_setsockopt_encap_port(struct sock *sk,
 	return 0;
 }
 
+static int sctp_setsockopt_probe_interval(struct sock *sk,
+					  struct sctp_probeinterval *params,
+					  unsigned int optlen)
+{
+	struct sctp_association *asoc;
+	struct sctp_transport *t;
+	__u32 probe_interval;
+
+	if (optlen != sizeof(*params))
+		return -EINVAL;
+
+	probe_interval = params->spi_interval;
+	if (probe_interval && probe_interval < SCTP_PROBE_TIMER_MIN)
+		return -EINVAL;
+
+	/* If an address other than INADDR_ANY is specified, and
+	 * no transport is found, then the request is invalid.
+	 */
+	if (!sctp_is_any(sk, (union sctp_addr *)&params->spi_address)) {
+		t = sctp_addr_id2transport(sk, &params->spi_address,
+					   params->spi_assoc_id);
+		if (!t)
+			return -EINVAL;
+
+		t->probe_interval = msecs_to_jiffies(probe_interval);
+		return 0;
+	}
+
+	/* Get association, if assoc_id != SCTP_FUTURE_ASSOC and the
+	 * socket is a one to many style socket, and an association
+	 * was not found, then the id was invalid.
+	 */
+	asoc = sctp_id2assoc(sk, params->spi_assoc_id);
+	if (!asoc && params->spi_assoc_id != SCTP_FUTURE_ASSOC &&
+	    sctp_style(sk, UDP))
+		return -EINVAL;
+
+	/* If changes are for association, also apply probe_interval to
+	 * each transport.
+	 */
+	if (asoc) {
+		list_for_each_entry(t, &asoc->peer.transport_addr_list, transports)
+			t->probe_interval = msecs_to_jiffies(probe_interval);
+
+		asoc->probe_interval = msecs_to_jiffies(probe_interval);
+		return 0;
+	}
+
+	sctp_sk(sk)->probe_interval = probe_interval;
+	return 0;
+}
+
 /* API 6.2 setsockopt(), getsockopt()
  *
  * Applications use setsockopt() and getsockopt() to set or retrieve
@@ -4703,6 +4755,9 @@ static int sctp_setsockopt(struct sock *sk, int level, int optname,
 	case SCTP_REMOTE_UDP_ENCAPS_PORT:
 		retval = sctp_setsockopt_encap_port(sk, kopt, optlen);
 		break;
+	case SCTP_PLPMTUD_PROBE_INTERVAL:
+		retval = sctp_setsockopt_probe_interval(sk, kopt, optlen);
+		break;
 	default:
 		retval = -ENOPROTOOPT;
 		break;
@@ -7906,6 +7961,66 @@ static int sctp_getsockopt_encap_port(struct sock *sk, int len,
 	return 0;
 }
 
+static int sctp_getsockopt_probe_interval(struct sock *sk, int len,
+					  char __user *optval,
+					  int __user *optlen)
+{
+	struct sctp_probeinterval params;
+	struct sctp_association *asoc;
+	struct sctp_transport *t;
+	__u32 probe_interval;
+
+	if (len < sizeof(params))
+		return -EINVAL;
+
+	len = sizeof(params);
+	if (copy_from_user(&params, optval, len))
+		return -EFAULT;
+
+	/* If an address other than INADDR_ANY is specified, and
+	 * no transport is found, then the request is invalid.
+	 */
+	if (!sctp_is_any(sk, (union sctp_addr *)&params.spi_address)) {
+		t = sctp_addr_id2transport(sk, &params.spi_address,
+					   params.spi_assoc_id);
+		if (!t) {
+			pr_debug("%s: failed no transport\n", __func__);
+			return -EINVAL;
+		}
+
+		probe_interval = jiffies_to_msecs(t->probe_interval);
+		goto out;
+	}
+
+	/* Get association, if assoc_id != SCTP_FUTURE_ASSOC and the
+	 * socket is a one to many style socket, and an association
+	 * was not found, then the id was invalid.
+	 */
+	asoc = sctp_id2assoc(sk, params.spi_assoc_id);
+	if (!asoc && params.spi_assoc_id != SCTP_FUTURE_ASSOC &&
+	    sctp_style(sk, UDP)) {
+		pr_debug("%s: failed no association\n", __func__);
+		return -EINVAL;
+	}
+
+	if (asoc) {
+		probe_interval = jiffies_to_msecs(asoc->probe_interval);
+		goto out;
+	}
+
+	probe_interval = sctp_sk(sk)->probe_interval;
+
+out:
+	params.spi_interval = probe_interval;
+	if (copy_to_user(optval, &params, len))
+		return -EFAULT;
+
+	if (put_user(len, optlen))
+		return -EFAULT;
+
+	return 0;
+}
+
 static int sctp_getsockopt(struct sock *sk, int level, int optname,
 			   char __user *optval, int __user *optlen)
 {
@@ -8129,6 +8244,9 @@ static int sctp_getsockopt(struct sock *sk, int level, int optname,
 	case SCTP_REMOTE_UDP_ENCAPS_PORT:
 		retval = sctp_getsockopt_encap_port(sk, len, optval, optlen);
 		break;
+	case SCTP_PLPMTUD_PROBE_INTERVAL:
+		retval = sctp_getsockopt_probe_interval(sk, len, optval, optlen);
+		break;
 	default:
 		retval = -ENOPROTOOPT;
 		break;