From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtpout5.r2.mail-out.ovh.net (smtpout5.r2.mail-out.ovh.net [54.36.141.5]) (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 4E1076D1AA for ; Fri, 12 Jan 2024 16:25:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=naccy.de Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=naccy.de Received: from ex4.mail.ovh.net (unknown [10.110.168.145]) by mo511.mail-out.ovh.net (Postfix) with ESMTPS id 5D0B32AEE0; Fri, 12 Jan 2024 14:00:12 +0000 (UTC) Received: from bf-dev-miffies.localdomain (130.93.52.54) by DAG10EX1.indiv4.local (172.16.2.91) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.35; Fri, 12 Jan 2024 15:00:11 +0100 From: Quentin Deslandes To: CC: David Ahern , Martin KaFai Lau , Quentin Deslandes , Subject: [PATCH v4 0/3] ss: pretty-printing BPF socket-local storage Date: Fri, 12 Jan 2024 15:04:26 +0100 Message-ID: <20240112140429.183344-1-qde@naccy.de> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-ClientProxiedBy: CAS13.indiv4.local (172.16.1.13) To DAG10EX1.indiv4.local (172.16.2.91) X-Ovh-Tracer-Id: 5038402083867389692 X-VR-SPAMSTATE: OK X-VR-SPAMSCORE: -100 X-VR-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrgedvkedrvdeihedgheekucetufdoteggodetrfdotffvucfrrhhofhhilhgvmecuqfggjfdpvefjgfevmfevgfenuceurghilhhouhhtmecuhedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmnecujfgurhephffvvefufffkofgggfgtihesthekredtredttdenucfhrhhomhepsfhuvghnthhinhcuffgvshhlrghnuggvshcuoehquggvsehnrggttgihrdguvgeqnecuggftrfgrthhtvghrnhepfeduteevveeluedvvedtieegleefveetjeeukeeigefgtdekudeuheduudegfeefnecukfhppeduvdejrddtrddtrddupddufedtrdelfedrhedvrdehgeenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepihhnvghtpeduvdejrddtrddtrddupdhmrghilhhfrhhomhepoehquggvsehnrggttgihrdguvgeqpdhnsggprhgtphhtthhopedupdhrtghpthhtohepnhgvthguvghvsehvghgvrhdrkhgvrhhnvghlrdhorhhgpdgushgrhhgvrhhnsehgmhgrihhlrdgtohhmpdhmrghrthhinhdrlhgruheskhgvrhhnvghlrdhorhhgpdhkvghrnhgvlhdqthgvrghmsehmvghtrgdrtghomhdpoffvtefjohhsthepmhhoheduuddpmhhouggvpehsmhhtphhouhht BPF allows programs to store socket-specific data using BPF_MAP_TYPE_SK_STORAGE maps. The data is attached to the socket itself, and Martin added INET_DIAG_REQ_SK_BPF_STORAGES, so it can be fetched using the INET_DIAG mechanism. Currently, ss doesn't request the socket-local data, this patch aims to fix this. The first patch requests the socket-local data for the requested map ID (--bpf-map-id=) or all the maps (--bpf-maps). It then prints the map_id in a dedicated column. Patch #2 uses libbpf and BTF to pretty print the map's content, like `bpftool map dump` would do. Patch #3 updates ss' man page to explain new options. While I think it makes sense for ss to provide the socket-local storage content for the sockets, it's difficult to conciliate the column-based output of ss and having readable socket-local data. Hence, the socket-local data is printed in a readable fashion over multiple lines under its socket statistics, independently of the column-based approach. Here is an example of ss' output with --bpf-maps: [...] ESTAB 340116 0 [...] map_id: 114 [ (struct my_sk_storage){ .field_hh = (char)3, (union){ .a = (int)17, .b = (int)17, }, } ] Changes from v3: * Minor refactoring to reduce number of HAVE_LIBBF usage. * Update ss' man page. * btf_dump structure created to print the socket-local data is cached in bpf_map_opts. Creation of the btf_dump structure is performed if needed, before printing the data. * If a map can't be pretty-printed, print its ID and a message instead of skipping it. * If show_all=true, send an empty message to the kernel to retrieve all the maps (as Martin suggested). Changes from v2: * bpf_map_opts_is_enabled is not inline anymore. * Add more #ifdef HAVE_LIBBPF to prevent compilation error if libbpf support is disabled. * Fix erroneous usage of args instead of _args in vout(). * Add missing btf__free() and close(fd). Changes from v1: * Remove the first patch from the series (fix) and submit it separately. * Remove double allocation of struct rtattr. * Close BPF map FDs on exit. * If bpf_map_get_fd_by_id() fails with ENOENT, print an error message and continue to the next map ID. * Fix typo in new command line option documentation. * Only use bpf_map_info.btf_value_type_id and ignore bpf_map_info.btf_vmlinux_value_type_id (unused for socket-local storage). * Use btf_dump__dump_type_data() instead of manually using BTF to pretty-print socket-local storage data. This change alone divides the size of the patch series by 2. Quentin Deslandes (3): ss: add support for BPF socket-local storage ss: pretty-print BPF socket-local storage ss: update man page to document --bpf-maps and --bpf-map-id= man/man8/ss.8 | 6 + misc/ss.c | 390 ++++++++++++++++++++++++++++++++++++++++++++++++-- 2 files changed, 387 insertions(+), 9 deletions(-) -- 2.43.0