From patchwork Fri Jan 12 14:04:27 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Quentin Deslandes X-Patchwork-Id: 13518517 X-Patchwork-Delegate: dsahern@gmail.com Received: from 2.mo547.mail-out.ovh.net (2.mo547.mail-out.ovh.net [46.105.35.152]) (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 3735564AAA for ; Fri, 12 Jan 2024 14:15:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=none (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 [10.108.9.49]) by mo547.mail-out.ovh.net (Postfix) with ESMTPS id C68CC20CED; 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 1/3] ss: add support for BPF socket-local storage Date: Fri, 12 Jan 2024 15:04:27 +0100 Message-ID: <20240112140429.183344-2-qde@naccy.de> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240112140429.183344-1-qde@naccy.de> References: <20240112140429.183344-1-qde@naccy.de> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ClientProxiedBy: CAS13.indiv4.local (172.16.1.13) To DAG10EX1.indiv4.local (172.16.2.91) X-Ovh-Tracer-Id: 5038402083939086076 X-VR-SPAMSTATE: OK X-VR-SPAMSCORE: -100 X-VR-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrgedvkedrvdeihedgheekucetufdoteggodetrfdotffvucfrrhhofhhilhgvmecuqfggjfdpvefjgfevmfevgfenuceurghilhhouhhtmecuhedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmnecujfgurhephffvvefufffkofgjfhgggfgtihesthekredtredttdenucfhrhhomhepsfhuvghnthhinhcuffgvshhlrghnuggvshcuoehquggvsehnrggttgihrdguvgeqnecuggftrfgrthhtvghrnhepfeduvedtffduleeuudetteffueeijeevfeetieefgfeugfeugeelhfehhfevfeevnecuffhomhgrihhnpehnrhgpmhgrphhsrdhiugenucfkphepuddvjedrtddrtddruddpudeftddrleefrdehvddrheegnecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehinhgvthepuddvjedrtddrtddruddpmhgrihhlfhhrohhmpeeoqhguvgesnhgrtggthidruggvqedpnhgspghrtghpthhtohepuddprhgtphhtthhopehnvghtuggvvhesvhhgvghrrdhkvghrnhgvlhdrohhrghdpughsrghhvghrnhesghhmrghilhdrtghomhdpmhgrrhhtihhnrdhlrghusehkvghrnhgvlhdrohhrghdpkhgvrhhnvghlqdhtvggrmhesmhgvthgrrdgtohhmpdfovfetjfhoshhtpehmohehgeejpdhmohguvgepshhmthhpohhuth While sock_diag is able to return BPF socket-local storage in response to INET_DIAG_REQ_SK_BPF_STORAGES requests, ss doesn't request it. This change introduces the --bpf-maps and --bpf-map-id= options to request BPF socket-local storage for all SK_STORAGE maps, or only specific ones. The bigger part of this change will check the requested map IDs and ensure they are valid. A new column has been added named "Socket storage" to print a list of map ID a given socket has data defined for. This column is disabled unless --bpf-maps or --bpf-map-id= is used. When --bpf-maps is used, ss will send an empty INET_DIAG_REQ_SK_BPF_STORAGES request, in return the kernel will send all the BPF socket-local storage entries for a given socket. When --bpf-map-id=ID is used, a file descriptor to the requested maps is open to 1) ensure the map doesn't disappear before the data is printed, and 2) ensure the map type is BPF_MAP_TYPE_SK_STORAGE. Signed-off-by: Quentin Deslandes Co-authored-by: Martin KaFai Lau Acked-by: Martin KaFai Lau --- misc/ss.c | 257 +++++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 254 insertions(+), 3 deletions(-) -- 2.43.0 diff --git a/misc/ss.c b/misc/ss.c index 900fefa4..f38e4744 100644 --- a/misc/ss.c +++ b/misc/ss.c @@ -51,6 +51,11 @@ #include #include +#ifdef HAVE_LIBBPF +#include +#include +#endif + #if HAVE_RPC #include #include @@ -101,6 +106,7 @@ enum col_id { COL_RADDR, COL_RSERV, COL_PROC, + COL_SKSTOR, COL_EXT, COL_MAX }; @@ -130,6 +136,7 @@ static struct column columns[] = { { ALIGN_RIGHT, "Peer Address:", " ", 0, 0, 0 }, { ALIGN_LEFT, "Port", "", 0, 0, 0 }, { ALIGN_LEFT, "Process", "", 0, 0, 0 }, + { ALIGN_LEFT, "Socket storage", "", 1, 0, 0 }, { ALIGN_LEFT, "", "", 0, 0, 0 }, }; @@ -3378,6 +3385,194 @@ static void parse_diag_msg(struct nlmsghdr *nlh, struct sockstat *s) memcpy(s->remote.data, r->id.idiag_dst, s->local.bytelen); } +#ifdef HAVE_LIBBPF + +#define MAX_NR_BPF_MAP_ID_OPTS 32 + +struct btf; + +static struct bpf_map_opts { + unsigned int nr_maps; + struct bpf_sk_storage_map_info { + unsigned int id; + int fd; + } maps[MAX_NR_BPF_MAP_ID_OPTS]; + bool show_all; +} bpf_map_opts; + +static void bpf_map_opts_mixed_error(void) +{ + fprintf(stderr, + "ss: --bpf-maps and --bpf-map-id cannot be used together\n"); +} + +static int bpf_map_opts_load_info(unsigned int map_id) +{ + struct bpf_map_info info = {}; + uint32_t len = sizeof(info); + int fd; + int r; + + if (bpf_map_opts.nr_maps == MAX_NR_BPF_MAP_ID_OPTS) { + fprintf(stderr, "ss: too many (> %u) BPF socket-local storage maps found, skipping map ID %u\n", + MAX_NR_BPF_MAP_ID_OPTS, map_id); + return 0; + } + + fd = bpf_map_get_fd_by_id(map_id); + if (fd == -1) { + if (errno == -ENOENT) + return 0; + + fprintf(stderr, "ss: cannot get fd for BPF map ID %u%s\n", + map_id, errno == EPERM ? + ": missing root permissions, CAP_BPF, or CAP_SYS_ADMIN" : ""); + return -1; + } + + r = bpf_obj_get_info_by_fd(fd, &info, &len); + if (r) { + fprintf(stderr, "ss: failed to get info for BPF map ID %u\n", + map_id); + close(fd); + return -1; + } + + if (info.type != BPF_MAP_TYPE_SK_STORAGE) { + fprintf(stderr, "ss: BPF map with ID %s has type '%s', expecting 'sk_storage'\n", + optarg, libbpf_bpf_map_type_str(info.type)); + close(fd); + return -1; + } + + bpf_map_opts.maps[bpf_map_opts.nr_maps].id = map_id; + bpf_map_opts.maps[bpf_map_opts.nr_maps++].fd = fd; + + return 0; +} + +static struct bpf_sk_storage_map_info *bpf_map_opts_get_info( + unsigned int map_id) +{ + unsigned int i; + int r; + + for (i = 0; i < bpf_map_opts.nr_maps; ++i) { + if (bpf_map_opts.maps[i].id == map_id) + return &bpf_map_opts.maps[i]; + } + + r = bpf_map_opts_load_info(map_id); + if (r) + return NULL; + + return &bpf_map_opts.maps[bpf_map_opts.nr_maps - 1]; +} + +static int bpf_map_opts_add_id(const char *optarg) +{ + size_t optarg_len; + unsigned long id; + char *end; + + if (bpf_map_opts.show_all) { + bpf_map_opts_mixed_error(); + return -1; + } + + optarg_len = strlen(optarg); + id = strtoul(optarg, &end, 0); + if (end != optarg + optarg_len || id == 0 || id >= UINT32_MAX) { + fprintf(stderr, "ss: invalid BPF map ID %s\n", optarg); + return -1; + } + + // Force lazy loading of the map's data. + if (!bpf_map_opts_get_info(id)) + return -ENOENT; + + return 0; +} + +static void bpf_map_opts_destroy(void) +{ + int i; + + for (i = 0; i < bpf_map_opts.nr_maps; ++i) + close(bpf_map_opts.maps[i].fd); +} + +static struct rtattr *bpf_map_opts_alloc_rta(void) +{ + struct rtattr *stgs_rta, *fd_rta; + size_t total_size; + unsigned int i; + void *buf; + + /* If bpf_map_opts.show_all == true, then bpf_map_opts.nr_maps == 0. We + * will send an empty message to the kernel, which will return all the + * socket-local data attached to a socket, no matter their map ID. */ + total_size = RTA_LENGTH(RTA_LENGTH(sizeof(int)) * bpf_map_opts.nr_maps); + buf = malloc(total_size); + if (!buf) + return NULL; + + stgs_rta = buf; + stgs_rta->rta_type = INET_DIAG_REQ_SK_BPF_STORAGES | NLA_F_NESTED; + stgs_rta->rta_len = total_size; + + buf = RTA_DATA(stgs_rta); + for (i = 0; i < bpf_map_opts.nr_maps; i++) { + int *fd; + + fd_rta = buf; + fd_rta->rta_type = SK_DIAG_BPF_STORAGE_REQ_MAP_FD; + fd_rta->rta_len = RTA_LENGTH(sizeof(int)); + + fd = RTA_DATA(fd_rta); + *fd = bpf_map_opts.maps[i].fd; + + buf += fd_rta->rta_len; + } + + return stgs_rta; +} + +static void show_sk_bpf_storages(struct rtattr *bpf_stgs) +{ + struct rtattr *tb[SK_DIAG_BPF_STORAGE_MAX + 1], *bpf_stg; + unsigned int rem; + + for (bpf_stg = RTA_DATA(bpf_stgs), rem = RTA_PAYLOAD(bpf_stgs); + RTA_OK(bpf_stg, rem); bpf_stg = RTA_NEXT(bpf_stg, rem)) { + + if ((bpf_stg->rta_type & NLA_TYPE_MASK) != SK_DIAG_BPF_STORAGE) + continue; + + parse_rtattr_nested(tb, SK_DIAG_BPF_STORAGE_MAX, + (struct rtattr *)bpf_stg); + + if (tb[SK_DIAG_BPF_STORAGE_MAP_ID]) { + out("map_id:%u ", + rta_getattr_u32(tb[SK_DIAG_BPF_STORAGE_MAP_ID])); + } + } +} + +static bool bpf_map_opts_is_enabled(void) +{ + return bpf_map_opts.nr_maps || bpf_map_opts.show_all; +} + +#else + +static bool bpf_map_opts_is_enabled(void) +{ + return false; +} + +#endif + static int inet_show_sock(struct nlmsghdr *nlh, struct sockstat *s) { @@ -3385,8 +3580,9 @@ static int inet_show_sock(struct nlmsghdr *nlh, struct inet_diag_msg *r = NLMSG_DATA(nlh); unsigned char v6only = 0; - parse_rtattr(tb, INET_DIAG_MAX, (struct rtattr *)(r+1), - nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*r))); + parse_rtattr_flags(tb, INET_DIAG_MAX, (struct rtattr *)(r+1), + nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*r)), + NLA_F_NESTED); if (tb[INET_DIAG_PROTOCOL]) s->type = rta_getattr_u8(tb[INET_DIAG_PROTOCOL]); @@ -3483,6 +3679,13 @@ static int inet_show_sock(struct nlmsghdr *nlh, } sctp_ino = s->ino; +#ifdef HAVE_LIBBPF + if (tb[INET_DIAG_SK_BPF_STORAGES]) { + field_set(COL_SKSTOR); + show_sk_bpf_storages(tb[INET_DIAG_SK_BPF_STORAGES]); + } +#endif + return 0; } @@ -3564,13 +3767,14 @@ static int sockdiag_send(int family, int fd, int protocol, struct filter *f) { struct sockaddr_nl nladdr = { .nl_family = AF_NETLINK }; DIAG_REQUEST(req, struct inet_diag_req_v2 r); + struct rtattr *bpf_stgs_rta = NULL; char *bc = NULL; int bclen; __u32 proto; struct msghdr msg; struct rtattr rta_bc; struct rtattr rta_proto; - struct iovec iov[5]; + struct iovec iov[6]; int iovlen = 1; if (family == PF_UNSPEC) @@ -3623,6 +3827,19 @@ static int sockdiag_send(int family, int fd, int protocol, struct filter *f) iovlen += 2; } +#ifdef HAVE_LIBBPF + if (bpf_map_opts_is_enabled()) { + bpf_stgs_rta = bpf_map_opts_alloc_rta(); + if (!bpf_stgs_rta) { + fprintf(stderr, "ss: cannot alloc request for --bpf-map\n"); + return -1; + } + + iov[iovlen++] = (struct iovec){ bpf_stgs_rta, bpf_stgs_rta->rta_len }; + req.nlh.nlmsg_len += bpf_stgs_rta->rta_len; + } +#endif + msg = (struct msghdr) { .msg_name = (void *)&nladdr, .msg_namelen = sizeof(nladdr), @@ -3631,10 +3848,13 @@ static int sockdiag_send(int family, int fd, int protocol, struct filter *f) }; if (sendmsg(fd, &msg, 0) < 0) { + free(bpf_stgs_rta); close(fd); return -1; } + free(bpf_stgs_rta); + return 0; } @@ -5355,6 +5575,10 @@ static void _usage(FILE *dest) " --tos show tos and priority information\n" " --cgroup show cgroup information\n" " -b, --bpf show bpf filter socket information\n" +#ifdef HAVE_LIBBPF +" --bpf-maps show all BPF socket-local storage maps\n" +" --bpf-map-id=MAP-ID show a BPF socket-local storage map\n" +#endif " -E, --events continually display sockets as they are destroyed\n" " -Z, --context display task SELinux security contexts\n" " -z, --contexts display task and socket SELinux security contexts\n" @@ -5480,6 +5704,9 @@ wrong_state: #define OPT_INET_SOCKOPT 262 +#define OPT_BPF_MAPS 263 +#define OPT_BPF_MAP_ID 264 + static const struct option long_opts[] = { { "numeric", 0, 0, 'n' }, { "resolve", 0, 0, 'r' }, @@ -5525,6 +5752,10 @@ static const struct option long_opts[] = { { "mptcp", 0, 0, 'M' }, { "oneline", 0, 0, 'O' }, { "inet-sockopt", 0, 0, OPT_INET_SOCKOPT }, +#ifdef HAVE_LIBBPF + { "bpf-maps", 0, 0, OPT_BPF_MAPS}, + { "bpf-map-id", 1, 0, OPT_BPF_MAP_ID}, +#endif { 0 } }; @@ -5730,6 +5961,19 @@ int main(int argc, char *argv[]) case OPT_INET_SOCKOPT: show_inet_sockopt = 1; break; +#ifdef HAVE_LIBBPF + case OPT_BPF_MAPS: + if (bpf_map_opts.nr_maps) { + bpf_map_opts_mixed_error(); + return -1; + } + bpf_map_opts.show_all = true; + break; + case OPT_BPF_MAP_ID: + if (bpf_map_opts_add_id(optarg)) + exit(1); + break; +#endif case 'h': help(); case '?': @@ -5828,6 +6072,9 @@ int main(int argc, char *argv[]) if (!(current_filter.states & (current_filter.states - 1))) columns[COL_STATE].disabled = 1; + if (bpf_map_opts_is_enabled()) + columns[COL_SKSTOR].disabled = 0; + if (show_header) print_header(); @@ -5864,6 +6111,10 @@ int main(int argc, char *argv[]) if (show_processes || show_threads || show_proc_ctx || show_sock_ctx) user_ent_destroy(); +#ifdef HAVE_LIBBPF + bpf_map_opts_destroy(); +#endif + render(); return 0;