From: Ido Schimmel <ido...@mellanox.com>

Timestamps are currently communicated to user space as 'struct
timespec', which is not considered y2038 safe since it uses a 32-bit
signed value for seconds.

Fix this while the API is still not part of any official kernel release
by using 64-bit nanoseconds timestamps instead.

Fixes: ca30707dee2b ("drop_monitor: Add packet alert mode")
Fixes: 5e58109b1ea4 ("drop_monitor: Add support for packet alert mode for 
hardware drops")
Signed-off-by: Ido Schimmel <ido...@mellanox.com>
---
Arnd, I have followed your recommendation to use 64-bit nanoseconds
timestamps. I would appreciate it if you could review this change.

Thanks!
---
 include/uapi/linux/net_dropmon.h |  2 +-
 net/core/drop_monitor.c          | 14 ++++++--------
 2 files changed, 7 insertions(+), 9 deletions(-)

diff --git a/include/uapi/linux/net_dropmon.h b/include/uapi/linux/net_dropmon.h
index 75a35dccb675..8bf79a9eb234 100644
--- a/include/uapi/linux/net_dropmon.h
+++ b/include/uapi/linux/net_dropmon.h
@@ -75,7 +75,7 @@ enum net_dm_attr {
        NET_DM_ATTR_PC,                         /* u64 */
        NET_DM_ATTR_SYMBOL,                     /* string */
        NET_DM_ATTR_IN_PORT,                    /* nested */
-       NET_DM_ATTR_TIMESTAMP,                  /* struct timespec */
+       NET_DM_ATTR_TIMESTAMP,                  /* u64 */
        NET_DM_ATTR_PROTO,                      /* u16 */
        NET_DM_ATTR_PAYLOAD,                    /* binary */
        NET_DM_ATTR_PAD,
diff --git a/net/core/drop_monitor.c b/net/core/drop_monitor.c
index bfc024024aa3..cc60cc22e2db 100644
--- a/net/core/drop_monitor.c
+++ b/net/core/drop_monitor.c
@@ -552,7 +552,7 @@ static size_t net_dm_packet_report_size(size_t payload_len)
               /* NET_DM_ATTR_IN_PORT */
               net_dm_in_port_size() +
               /* NET_DM_ATTR_TIMESTAMP */
-              nla_total_size(sizeof(struct timespec)) +
+              nla_total_size(sizeof(u64)) +
               /* NET_DM_ATTR_ORIG_LEN */
               nla_total_size(sizeof(u32)) +
               /* NET_DM_ATTR_PROTO */
@@ -592,7 +592,6 @@ static int net_dm_packet_report_fill(struct sk_buff *msg, 
struct sk_buff *skb,
        u64 pc = (u64)(uintptr_t) NET_DM_SKB_CB(skb)->pc;
        char buf[NET_DM_MAX_SYMBOL_LEN];
        struct nlattr *attr;
-       struct timespec ts;
        void *hdr;
        int rc;
 
@@ -615,8 +614,8 @@ static int net_dm_packet_report_fill(struct sk_buff *msg, 
struct sk_buff *skb,
        if (rc)
                goto nla_put_failure;
 
-       if (ktime_to_timespec_cond(skb->tstamp, &ts) &&
-           nla_put(msg, NET_DM_ATTR_TIMESTAMP, sizeof(ts), &ts))
+       if (nla_put_u64_64bit(msg, NET_DM_ATTR_TIMESTAMP,
+                             ktime_to_ns(skb->tstamp), NET_DM_ATTR_PAD))
                goto nla_put_failure;
 
        if (nla_put_u32(msg, NET_DM_ATTR_ORIG_LEN, skb->len))
@@ -716,7 +715,7 @@ net_dm_hw_packet_report_size(size_t payload_len,
               /* NET_DM_ATTR_IN_PORT */
               net_dm_in_port_size() +
               /* NET_DM_ATTR_TIMESTAMP */
-              nla_total_size(sizeof(struct timespec)) +
+              nla_total_size(sizeof(u64)) +
               /* NET_DM_ATTR_ORIG_LEN */
               nla_total_size(sizeof(u32)) +
               /* NET_DM_ATTR_PROTO */
@@ -730,7 +729,6 @@ static int net_dm_hw_packet_report_fill(struct sk_buff *msg,
 {
        struct net_dm_hw_metadata *hw_metadata;
        struct nlattr *attr;
-       struct timespec ts;
        void *hdr;
 
        hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
@@ -761,8 +759,8 @@ static int net_dm_hw_packet_report_fill(struct sk_buff *msg,
                        goto nla_put_failure;
        }
 
-       if (ktime_to_timespec_cond(skb->tstamp, &ts) &&
-           nla_put(msg, NET_DM_ATTR_TIMESTAMP, sizeof(ts), &ts))
+       if (nla_put_u64_64bit(msg, NET_DM_ATTR_TIMESTAMP,
+                             ktime_to_ns(skb->tstamp), NET_DM_ATTR_PAD))
                goto nla_put_failure;
 
        if (nla_put_u32(msg, NET_DM_ATTR_ORIG_LEN, skb->len))
-- 
2.21.0

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