When the netlink socket of a port (used for receiving link up/down
events) had an error (e.g. ENOBUFS due to the kernel sending too many
messages), ptp4l switched the port to the faulty state, but it kept
getting POLLERR on the socket and logged "port 1: unexpected socket
error" in an infinite loop.
Unlike the PTP event and general sockets, the netlink sockets cannot be
closed in the faulty state as they are needed to receive the link up event.
Instead, receive and clear the error on all descriptors getting POLLERR
with getsockopt(SO_ERROR). Include the error in the log message together
with the descriptor index to make it easier to debug issues like this in
future.
Signed-off-by: Miroslav Lichvar <mlich...@redhat.com>
---
clock.c | 6 ++++--
sk.c | 14 ++++++++++++++
sk.h | 7 +++++++
3 files changed, 25 insertions(+), 2 deletions(-)
diff --git a/clock.c b/clock.c
index 75d7c40..fe08d48 100644
--- a/clock.c
+++ b/clock.c
@@ -1790,8 +1790,10 @@ int clock_poll(struct clock *c)
if (cur[i].revents & (POLLIN|POLLPRI|POLLERR)) {
prior_state = port_state(p);
if (cur[i].revents & POLLERR) {
- pr_err("%s: unexpected socket error",
- port_log_name(p));
+ int error = sk_get_error(cur[i].fd);
+ pr_err("%s: error on fda[%d]: %s",
+ port_log_name(p), i,
+ strerror(error));
event = EV_FAULT_DETECTED;
} else {
event = port_event(p, i);
diff --git a/sk.c b/sk.c
index 2e4ef2c..6a9e5b8 100644
--- a/sk.c
+++ b/sk.c
@@ -491,6 +491,20 @@ int sk_receive(int fd, void *buf, int buflen,
return cnt < 0 ? -errno : cnt;
}
+int sk_get_error(int fd)
+{
+ socklen_t len;
+ int error;
+
+ len = sizeof (error);
+ if (getsockopt(fd, SOL_SOCKET, SO_ERROR, &error, &len) < 0) {
+ pr_err("getsockopt SO_ERROR failed: %m");
+ return -1;
+ }
+
+ return error;
+}
+
int sk_set_priority(int fd, int family, uint8_t dscp)
{
int level, optname, tos;
diff --git a/sk.h b/sk.h
index df105d6..76062d0 100644
--- a/sk.h
+++ b/sk.h
@@ -130,6 +130,13 @@ int sk_interface_addr(const char *name, int family, struct
address *addr);
int sk_receive(int fd, void *buf, int buflen,
struct address *addr, struct hw_timestamp *hwts, int flags);
+/**
+ * Get and clear a pending socket error.
+ * @param fd An open socket.
+ * @return The error.
+ */
+int sk_get_error(int fd);
+
/**
* Set DSCP value for socket.
* @param fd An open socket.
--
2.40.0
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