From 171c3b151118a2fe0fc1e2a9d1b5a1570cfe82d2 Mon Sep 17 00:00:00 2001 From: Richard Sanger Date: Wed, 12 May 2021 13:31:22 +1200 Subject: [PATCH] net: packetmmap: fix only tx timestamp on request The packetmmap tx ring should only return timestamps if requested via setsockopt PACKET_TIMESTAMP, as documented. This allows compatibility with non-timestamp aware user-space code which checks tp_status == TP_STATUS_AVAILABLE; not expecting additional timestamp flags to be set in tp_status. Fixes: b9c32fb27170 ("packet: if hw/sw ts enabled in rx/tx ring, report which ts we got") Cc: Daniel Borkmann Cc: Willem de Bruijn Signed-off-by: Richard Sanger Signed-off-by: David S. Miller --- net/packet/af_packet.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index ba96db1880ea..ae906eb4b269 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -422,7 +422,8 @@ static __u32 tpacket_get_timestamp(struct sk_buff *skb, struct timespec64 *ts, ktime_to_timespec64_cond(shhwtstamps->hwtstamp, ts)) return TP_STATUS_TS_RAW_HARDWARE; - if (ktime_to_timespec64_cond(skb->tstamp, ts)) + if ((flags & SOF_TIMESTAMPING_SOFTWARE) && + ktime_to_timespec64_cond(skb->tstamp, ts)) return TP_STATUS_TS_SOFTWARE; return 0; @@ -2340,7 +2341,12 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev, skb_copy_bits(skb, 0, h.raw + macoff, snaplen); - if (!(ts_status = tpacket_get_timestamp(skb, &ts, po->tp_tstamp))) + /* Always timestamp; prefer an existing software timestamp taken + * closer to the time of capture. + */ + ts_status = tpacket_get_timestamp(skb, &ts, + po->tp_tstamp | SOF_TIMESTAMPING_SOFTWARE); + if (!ts_status) ktime_get_real_ts64(&ts); status |= ts_status;