From aad9c8c470f2a8321a99eb053630ce0e199558d6 Mon Sep 17 00:00:00 2001 From: Miroslav Lichvar Date: Fri, 19 May 2017 17:52:38 +0200 Subject: [PATCH] net: add new control message for incoming HW-timestamped packets Add SOF_TIMESTAMPING_OPT_PKTINFO option to request a new control message for incoming packets with hardware timestamps. It contains the index of the real interface which received the packet and the length of the packet at layer 2. The index is useful with bonding, bridges and other interfaces, where IP_PKTINFO doesn't allow applications to determine which PHC made the timestamp. With the L2 length (and link speed) it is possible to transpose preamble timestamps to trailer timestamps, which are used in the NTP protocol. While this information could be provided by two new socket options independently from timestamping, it doesn't look like they would be very useful. With this option any performance impact is limited to hardware timestamping. Use dev_get_by_napi_id() to get the device and its index. On kernels with disabled CONFIG_NET_RX_BUSY_POLL or drivers not using NAPI, a zero index will be returned in the control message. CC: Richard Cochran Acked-by: Willem de Bruijn Signed-off-by: Miroslav Lichvar Signed-off-by: David S. Miller --- Documentation/networking/timestamping.txt | 10 +++++++++ include/uapi/asm-generic/socket.h | 2 ++ include/uapi/linux/net_tstamp.h | 11 ++++++++- net/socket.c | 27 ++++++++++++++++++++++- 4 files changed, 48 insertions(+), 2 deletions(-) diff --git a/Documentation/networking/timestamping.txt b/Documentation/networking/timestamping.txt index 96f50694a748..ce11e3a08c0d 100644 --- a/Documentation/networking/timestamping.txt +++ b/Documentation/networking/timestamping.txt @@ -193,6 +193,16 @@ SOF_TIMESTAMPING_OPT_STATS: the transmit timestamps, such as how long a certain block of data was limited by peer's receiver window. +SOF_TIMESTAMPING_OPT_PKTINFO: + + Enable the SCM_TIMESTAMPING_PKTINFO control message for incoming + packets with hardware timestamps. The message contains struct + scm_ts_pktinfo, which supplies the index of the real interface which + received the packet and its length at layer 2. A valid (non-zero) + interface index will be returned only if CONFIG_NET_RX_BUSY_POLL is + enabled and the driver is using NAPI. The struct contains also two + other fields, but they are reserved and undefined. + New applications are encouraged to pass SOF_TIMESTAMPING_OPT_ID to disambiguate timestamps and SOF_TIMESTAMPING_OPT_TSONLY to operate regardless of the setting of sysctl net.core.tstamp_allow_data. diff --git a/include/uapi/asm-generic/socket.h b/include/uapi/asm-generic/socket.h index 2b488565599d..a5f6e819fafd 100644 --- a/include/uapi/asm-generic/socket.h +++ b/include/uapi/asm-generic/socket.h @@ -100,4 +100,6 @@ #define SO_COOKIE 57 +#define SCM_TIMESTAMPING_PKTINFO 58 + #endif /* __ASM_GENERIC_SOCKET_H */ diff --git a/include/uapi/linux/net_tstamp.h b/include/uapi/linux/net_tstamp.h index 0749fb13e517..dee74d39da94 100644 --- a/include/uapi/linux/net_tstamp.h +++ b/include/uapi/linux/net_tstamp.h @@ -9,6 +9,7 @@ #ifndef _NET_TIMESTAMPING_H #define _NET_TIMESTAMPING_H +#include #include /* for SO_TIMESTAMPING */ /* SO_TIMESTAMPING gets an integer bit field comprised of these values */ @@ -26,8 +27,9 @@ enum { SOF_TIMESTAMPING_OPT_CMSG = (1<<10), SOF_TIMESTAMPING_OPT_TSONLY = (1<<11), SOF_TIMESTAMPING_OPT_STATS = (1<<12), + SOF_TIMESTAMPING_OPT_PKTINFO = (1<<13), - SOF_TIMESTAMPING_LAST = SOF_TIMESTAMPING_OPT_STATS, + SOF_TIMESTAMPING_LAST = SOF_TIMESTAMPING_OPT_PKTINFO, SOF_TIMESTAMPING_MASK = (SOF_TIMESTAMPING_LAST - 1) | SOF_TIMESTAMPING_LAST }; @@ -130,4 +132,11 @@ enum hwtstamp_rx_filters { HWTSTAMP_FILTER_NTP_ALL, }; +/* SCM_TIMESTAMPING_PKTINFO control message */ +struct scm_ts_pktinfo { + __u32 if_index; + __u32 pkt_length; + __u32 reserved[2]; +}; + #endif /* _NET_TIMESTAMPING_H */ diff --git a/net/socket.c b/net/socket.c index c2564eb25c6b..67db7d8a3b81 100644 --- a/net/socket.c +++ b/net/socket.c @@ -662,6 +662,27 @@ static bool skb_is_err_queue(const struct sk_buff *skb) return skb->pkt_type == PACKET_OUTGOING; } +static void put_ts_pktinfo(struct msghdr *msg, struct sk_buff *skb) +{ + struct scm_ts_pktinfo ts_pktinfo; + struct net_device *orig_dev; + + if (!skb_mac_header_was_set(skb)) + return; + + memset(&ts_pktinfo, 0, sizeof(ts_pktinfo)); + + rcu_read_lock(); + orig_dev = dev_get_by_napi_id(skb_napi_id(skb)); + if (orig_dev) + ts_pktinfo.if_index = orig_dev->ifindex; + rcu_read_unlock(); + + ts_pktinfo.pkt_length = skb->len - skb_mac_offset(skb); + put_cmsg(msg, SOL_SOCKET, SCM_TIMESTAMPING_PKTINFO, + sizeof(ts_pktinfo), &ts_pktinfo); +} + /* * called from sock_recv_timestamp() if sock_flag(sk, SOCK_RCVTSTAMP) */ @@ -699,8 +720,12 @@ void __sock_recv_timestamp(struct msghdr *msg, struct sock *sk, empty = 0; if (shhwtstamps && (sk->sk_tsflags & SOF_TIMESTAMPING_RAW_HARDWARE) && - ktime_to_timespec_cond(shhwtstamps->hwtstamp, tss.ts + 2)) + ktime_to_timespec_cond(shhwtstamps->hwtstamp, tss.ts + 2)) { empty = 0; + if ((sk->sk_tsflags & SOF_TIMESTAMPING_OPT_PKTINFO) && + !skb_is_err_queue(skb)) + put_ts_pktinfo(msg, skb); + } if (!empty) { put_cmsg(msg, SOL_SOCKET, SCM_TIMESTAMPING, sizeof(tss), &tss); -- 2.20.1