From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-179.mta1.migadu.com (out-179.mta1.migadu.com [95.215.58.179]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 60E831A3A9C for ; Mon, 2 Sep 2024 19:41:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.179 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725306062; cv=none; b=Grk/E7IASikC0T2+K1lIBqEVsulLomwe32Qxf+Z3JyYp4+jprJgAF/t5anAbKrasC3iY6Nn+7IrgjpNoCP/teFvGQfNw9BW/wMtTvuyUwtUjt2lhYcGqgaEZ4V3MatX8yv/OS4nfvY1xU13lZMfA+QuKUJVLHNa+0aMjgKd/hOs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725306062; c=relaxed/simple; bh=+rdbypgY3jruO8sE9yBRH6AGrE22Yb3NCyy217HIEW8=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=hvZbQ4UWMfyZ7Fhu06cGiVL4qPMi/rWgUjI4+vZT45yNkfxGnNJJ+BNO6aWbPLvZbi/eZiZPYsfvUzOmzKKLpz4UEEQNolhcWBuLkX9/r4KLb0yUmJgnJWKB6IPZ/tSj7TgS4B9wAG1OT8wHxtHnicqtVJ9u5XVqRBlH5Qq2+wI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=UiTZZRHs; arc=none smtp.client-ip=95.215.58.179 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="UiTZZRHs" Message-ID: <0d79442d-438b-4960-8daf-2f178a210e64@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1725306058; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=dzlbDAITDcuk5laa7erkI5zpP+0Kg4IbsqcaefXueeg=; b=UiTZZRHsuSc8MRAEUmv9Wg+WBbofEbxwc4D7FWoj3EYkH7/dho4Ue1Rk99211ovpiSY7Rg 60z2LtQABr8O55H1sufxuPyERI5Lfv/Gzg7nBMUr1hFdtQbGIJeCrrLGeyvaAqb0o7g9DY aGmj3cIFhPIUvvcKtOlqZZpI7KSzifE= Date: Mon, 2 Sep 2024 20:40:51 +0100 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH net-next v2 1/2] net_tstamp: add SCM_TS_OPT_ID to provide OPT_ID in control message To: Willem de Bruijn Cc: Willem de Bruijn , Jakub Kicinski , Paolo Abeni , David Ahern , netdev@vger.kernel.org, Jason Xing References: <20240902130937.457115-1-vadfed@meta.com> <66d5def0ca56_66cf629420@willemb.c.googlers.com.notmuch> Content-Language: en-US X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Vadim Fedorenko In-Reply-To: <66d5def0ca56_66cf629420@willemb.c.googlers.com.notmuch> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT On 02/09/2024 16:51, Willem de Bruijn wrote: > Jason Xing wrote: >> On Mon, Sep 2, 2024 at 9:09 PM Vadim Fedorenko wrote: >>> >>> SOF_TIMESTAMPING_OPT_ID socket option flag gives a way to correlate TX >>> timestamps and packets sent via socket. Unfortunately, there is no way >>> to reliably predict socket timestamp ID value in case of error returned >>> by sendmsg. For UDP sockets it's impossible because of lockless >>> nature of UDP transmit, several threads may send packets in parallel. In >>> case of RAW sockets MSG_MORE option makes things complicated. More >>> details are in the conversation [1]. >>> This patch adds new control message type to give user-space >>> software an opportunity to control the mapping between packets and >>> values by providing ID with each sendmsg. This works fine for UDP >>> sockets only, and explicit check is added to control message parser. >>> >>> [1] https://lore.kernel.org/netdev/CALCETrU0jB+kg0mhV6A8mrHfTE1D1pr1SD_B9Eaa9aDPfgHdtA@mail.gmail.com/ >>> >>> Signed-off-by: Vadim Fedorenko >>> --- >>> Documentation/networking/timestamping.rst | 14 ++++++++++++++ >>> arch/alpha/include/uapi/asm/socket.h | 4 +++- >>> arch/mips/include/uapi/asm/socket.h | 2 ++ >>> arch/parisc/include/uapi/asm/socket.h | 2 ++ >>> arch/sparc/include/uapi/asm/socket.h | 2 ++ >>> include/net/inet_sock.h | 4 +++- >>> include/net/sock.h | 1 + >>> include/uapi/asm-generic/socket.h | 2 ++ >>> include/uapi/linux/net_tstamp.h | 3 ++- >>> net/core/sock.c | 12 ++++++++++++ >>> net/ethtool/common.c | 1 + >>> net/ipv4/ip_output.c | 16 ++++++++++++---- >>> net/ipv6/ip6_output.c | 16 ++++++++++++---- >>> 13 files changed, 68 insertions(+), 11 deletions(-) >>> >>> diff --git a/Documentation/networking/timestamping.rst b/Documentation/networking/timestamping.rst >>> index 5e93cd71f99f..93b0901e4e8e 100644 >>> --- a/Documentation/networking/timestamping.rst >>> +++ b/Documentation/networking/timestamping.rst >>> @@ -193,6 +193,20 @@ SOF_TIMESTAMPING_OPT_ID: >>> among all possibly concurrently outstanding timestamp requests for >>> that socket. >>> >>> + With this option enabled user-space application can provide custom >>> + ID for each message sent via UDP socket with control message with >>> + type set to SCM_TS_OPT_ID:: >>> + >>> + struct msghdr *msg; >>> + ... >>> + cmsg = CMSG_FIRSTHDR(msg); >>> + cmsg->cmsg_level = SOL_SOCKET; >>> + cmsg->cmsg_type = SO_TIMESTAMPING; >>> + cmsg->cmsg_len = CMSG_LEN(sizeof(__u32)); >>> + *((__u32 *) CMSG_DATA(cmsg)) = opt_id; >>> + err = sendmsg(fd, msg, 0); >>> + >>> + >>> SOF_TIMESTAMPING_OPT_ID_TCP: >>> Pass this modifier along with SOF_TIMESTAMPING_OPT_ID for new TCP >>> timestamping applications. SOF_TIMESTAMPING_OPT_ID defines how the >>> diff --git a/arch/alpha/include/uapi/asm/socket.h b/arch/alpha/include/uapi/asm/socket.h >>> index e94f621903fe..0698e6662cdf 100644 >>> --- a/arch/alpha/include/uapi/asm/socket.h >>> +++ b/arch/alpha/include/uapi/asm/socket.h >>> @@ -10,7 +10,7 @@ >>> * Note: we only bother about making the SOL_SOCKET options >>> * same as OSF/1, as that's all that "normal" programs are >>> * likely to set. We don't necessarily want to be binary >>> - * compatible with _everything_. >>> + * compatible with _everything_. >>> */ >>> #define SOL_SOCKET 0xffff >>> >>> @@ -140,6 +140,8 @@ >>> #define SO_PASSPIDFD 76 >>> #define SO_PEERPIDFD 77 >>> >>> +#define SCM_TS_OPT_ID 78 >>> + >>> #if !defined(__KERNEL__) >>> >>> #if __BITS_PER_LONG == 64 >>> diff --git a/arch/mips/include/uapi/asm/socket.h b/arch/mips/include/uapi/asm/socket.h >>> index 60ebaed28a4c..bb3dc8feb205 100644 >>> --- a/arch/mips/include/uapi/asm/socket.h >>> +++ b/arch/mips/include/uapi/asm/socket.h >>> @@ -151,6 +151,8 @@ >>> #define SO_PASSPIDFD 76 >>> #define SO_PEERPIDFD 77 >>> >>> +#define SCM_TS_OPT_ID 78 >>> + >>> #if !defined(__KERNEL__) >>> >>> #if __BITS_PER_LONG == 64 >>> diff --git a/arch/parisc/include/uapi/asm/socket.h b/arch/parisc/include/uapi/asm/socket.h >>> index be264c2b1a11..c3ab3b3289eb 100644 >>> --- a/arch/parisc/include/uapi/asm/socket.h >>> +++ b/arch/parisc/include/uapi/asm/socket.h >>> @@ -132,6 +132,8 @@ >>> #define SO_PASSPIDFD 0x404A >>> #define SO_PEERPIDFD 0x404B >>> >>> +#define SCM_TS_OPT_ID 0x404C >>> + >>> #if !defined(__KERNEL__) >>> >>> #if __BITS_PER_LONG == 64 >>> diff --git a/arch/sparc/include/uapi/asm/socket.h b/arch/sparc/include/uapi/asm/socket.h >>> index 682da3714686..9b40f0a57fbc 100644 >>> --- a/arch/sparc/include/uapi/asm/socket.h >>> +++ b/arch/sparc/include/uapi/asm/socket.h >>> @@ -133,6 +133,8 @@ >>> #define SO_PASSPIDFD 0x0055 >>> #define SO_PEERPIDFD 0x0056 >>> >>> +#define SCM_TS_OPT_ID 0x0057 >>> + >>> #if !defined(__KERNEL__) >>> >>> >>> diff --git a/include/net/inet_sock.h b/include/net/inet_sock.h >>> index 394c3b66065e..2161d50cf0fd 100644 >>> --- a/include/net/inet_sock.h >>> +++ b/include/net/inet_sock.h >>> @@ -174,6 +174,7 @@ struct inet_cork { >>> __s16 tos; >>> char priority; >>> __u16 gso_size; >>> + u32 ts_opt_id; >>> u64 transmit_time; >>> u32 mark; >>> }; >>> @@ -241,7 +242,8 @@ struct inet_sock { >>> struct inet_cork_full cork; >>> }; >>> >>> -#define IPCORK_OPT 1 /* ip-options has been held in ipcork.opt */ >>> +#define IPCORK_OPT 1 /* ip-options has been held in ipcork.opt */ >>> +#define IPCORK_TS_OPT_ID 2 /* timestmap opt id has been provided in cmsg */ >>> >>> enum { >>> INET_FLAGS_PKTINFO = 0, >>> diff --git a/include/net/sock.h b/include/net/sock.h >>> index f51d61fab059..73e21dad5660 100644 >>> --- a/include/net/sock.h >>> +++ b/include/net/sock.h >>> @@ -1794,6 +1794,7 @@ struct sockcm_cookie { >>> u64 transmit_time; >>> u32 mark; >>> u32 tsflags; >>> + u32 ts_opt_id; >>> }; >>> >>> static inline void sockcm_init(struct sockcm_cookie *sockc, >>> diff --git a/include/uapi/asm-generic/socket.h b/include/uapi/asm-generic/socket.h >>> index 8ce8a39a1e5f..db3df3e74b01 100644 >>> --- a/include/uapi/asm-generic/socket.h >>> +++ b/include/uapi/asm-generic/socket.h >>> @@ -135,6 +135,8 @@ >>> #define SO_PASSPIDFD 76 >>> #define SO_PEERPIDFD 77 >>> >>> +#define SCM_TS_OPT_ID 78 >>> + >>> #if !defined(__KERNEL__) >>> >>> #if __BITS_PER_LONG == 64 || (defined(__x86_64__) && defined(__ILP32__)) >>> diff --git a/include/uapi/linux/net_tstamp.h b/include/uapi/linux/net_tstamp.h >>> index a2c66b3d7f0f..e2f145e3f3a1 100644 >>> --- a/include/uapi/linux/net_tstamp.h >>> +++ b/include/uapi/linux/net_tstamp.h >>> @@ -32,8 +32,9 @@ enum { >>> SOF_TIMESTAMPING_OPT_TX_SWHW = (1<<14), >>> SOF_TIMESTAMPING_BIND_PHC = (1 << 15), >>> SOF_TIMESTAMPING_OPT_ID_TCP = (1 << 16), >>> + SOF_TIMESTAMPING_OPT_ID_CMSG = (1 << 17), >> >> I'm not sure if the new flag needs to be documented as well? After >> this patch, people may search the key word in the documentation file >> and then find nothing. >> >> If we have this flag here, normally it means we can pass it through >> setsockopt, so is it expected? If it's an exception, I reckon that we >> can forbid passing/setting this option in sock_set_timestamping() and >> document this rule? > > Good point, thanks. > > It must definitely not be part of SOF_TIMESTAMPING_MASK. My bad for > suggesting without giving it much thought. > > The bit is kernel-internal. No need to even mention it in user-facing > documentation. But anyone reading net_tstamp.h might wonder what it > does. > > It should not even be in a UAPI header, but in an internal one. > Probably include/net/sock.h, near SK_FLAGS_TIMESTAMP. > > Maybe we can reserve bit 31 in u32 sk_tsflags. And if we ever have > to double that flag size, it can move up to 63, as it is not UAPI in > any way. This is a workaround to having a separate flags field in > sockcm_cookie. > > And have a BUILD_BUG_ON if SOF_TIMESTAMPING_LAST reaches this reserved > region. Yeah, I was also thinking of it not being UAPI, that's why I tried to avoid it in my RFC using 0 as a reserved value. Do you think SK_FLAGS_CMSG_TS_OPT_ID is good naming for it? Thanks, Vadim