| /* SPDX-License-Identifier: LGPL-2.1-or-later */ |
| |
| #include <errno.h> |
| #include <linux/filter.h> |
| #include <linux/netlink.h> |
| #include <linux/sockios.h> |
| #include <sys/ioctl.h> |
| #include <unistd.h> |
| |
| #include "sd-device.h" |
| #include "sd-event.h" |
| |
| #include "MurmurHash2.h" |
| #include "alloc-util.h" |
| #include "device-monitor-private.h" |
| #include "device-private.h" |
| #include "device-util.h" |
| #include "errno-util.h" |
| #include "fd-util.h" |
| #include "format-util.h" |
| #include "hashmap.h" |
| #include "io-util.h" |
| #include "missing_socket.h" |
| #include "mountpoint-util.h" |
| #include "set.h" |
| #include "socket-util.h" |
| #include "string-util.h" |
| #include "strv.h" |
| |
| struct sd_device_monitor { |
| unsigned n_ref; |
| |
| int sock; |
| union sockaddr_union snl; |
| union sockaddr_union snl_trusted_sender; |
| bool bound; |
| |
| Hashmap *subsystem_filter; |
| Set *tag_filter; |
| Hashmap *match_sysattr_filter; |
| Hashmap *nomatch_sysattr_filter; |
| Set *match_parent_filter; |
| Set *nomatch_parent_filter; |
| bool filter_uptodate; |
| |
| sd_event *event; |
| sd_event_source *event_source; |
| sd_device_monitor_handler_t callback; |
| void *userdata; |
| }; |
| |
| #define UDEV_MONITOR_MAGIC 0xfeedcafe |
| |
| typedef struct monitor_netlink_header { |
| /* "libudev" prefix to distinguish libudev and kernel messages */ |
| char prefix[8]; |
| /* Magic to protect against daemon <-> Library message format mismatch |
| * Used in the kernel from socket filter rules; needs to be stored in network order */ |
| unsigned magic; |
| /* Total length of header structure known to the sender */ |
| unsigned header_size; |
| /* Properties string buffer */ |
| unsigned properties_off; |
| unsigned properties_len; |
| /* Hashes of primary device properties strings, to let libudev subscribers |
| * use in-kernel socket filters; values need to be stored in network order */ |
| unsigned filter_subsystem_hash; |
| unsigned filter_devtype_hash; |
| unsigned filter_tag_bloom_hi; |
| unsigned filter_tag_bloom_lo; |
| } monitor_netlink_header; |
| |
| static int monitor_set_nl_address(sd_device_monitor *m) { |
| union sockaddr_union snl; |
| socklen_t addrlen; |
| |
| assert(m); |
| |
| /* Get the address the kernel has assigned us. |
| * It is usually, but not necessarily the pid. */ |
| addrlen = sizeof(struct sockaddr_nl); |
| if (getsockname(m->sock, &snl.sa, &addrlen) < 0) |
| return -errno; |
| |
| m->snl.nl.nl_pid = snl.nl.nl_pid; |
| return 0; |
| } |
| |
| int device_monitor_allow_unicast_sender(sd_device_monitor *m, sd_device_monitor *sender) { |
| assert(m); |
| assert(sender); |
| |
| m->snl_trusted_sender.nl.nl_pid = sender->snl.nl.nl_pid; |
| return 0; |
| } |
| |
| _public_ int sd_device_monitor_set_receive_buffer_size(sd_device_monitor *m, size_t size) { |
| assert_return(m, -EINVAL); |
| |
| return fd_set_rcvbuf(m->sock, size, false); |
| } |
| |
| int device_monitor_disconnect(sd_device_monitor *m) { |
| assert(m); |
| |
| m->sock = safe_close(m->sock); |
| return 0; |
| } |
| |
| int device_monitor_get_fd(sd_device_monitor *m) { |
| assert(m); |
| |
| return m->sock; |
| } |
| |
| int device_monitor_new_full(sd_device_monitor **ret, MonitorNetlinkGroup group, int fd) { |
| _cleanup_(sd_device_monitor_unrefp) sd_device_monitor *m = NULL; |
| _cleanup_close_ int sock = -1; |
| int r; |
| |
| assert(group >= 0 && group < _MONITOR_NETLINK_GROUP_MAX); |
| assert_return(ret, -EINVAL); |
| |
| if (group == MONITOR_GROUP_UDEV && |
| access("/run/udev/control", F_OK) < 0 && |
| dev_is_devtmpfs() <= 0) { |
| |
| /* |
| * We do not support subscribing to uevents if no instance of |
| * udev is running. Uevents would otherwise broadcast the |
| * processing data of the host into containers, which is not |
| * desired. |
| * |
| * Containers will currently not get any udev uevents, until |
| * a supporting infrastructure is available. |
| * |
| * We do not set a netlink multicast group here, so the socket |
| * will not receive any messages. |
| */ |
| |
| log_debug("sd-device-monitor: The udev service seems not to be active, disabling the monitor"); |
| group = MONITOR_GROUP_NONE; |
| } |
| |
| if (fd < 0) { |
| sock = socket(PF_NETLINK, SOCK_RAW|SOCK_CLOEXEC|SOCK_NONBLOCK, NETLINK_KOBJECT_UEVENT); |
| if (sock < 0) |
| return log_debug_errno(errno, "sd-device-monitor: Failed to create socket: %m"); |
| } |
| |
| m = new(sd_device_monitor, 1); |
| if (!m) |
| return -ENOMEM; |
| |
| *m = (sd_device_monitor) { |
| .n_ref = 1, |
| .sock = fd >= 0 ? fd : TAKE_FD(sock), |
| .bound = fd >= 0, |
| .snl.nl.nl_family = AF_NETLINK, |
| .snl.nl.nl_groups = group, |
| }; |
| |
| if (fd >= 0) { |
| r = monitor_set_nl_address(m); |
| if (r < 0) { |
| log_debug_errno(r, "sd-device-monitor: Failed to set netlink address: %m"); |
| goto fail; |
| } |
| } |
| |
| if (DEBUG_LOGGING) { |
| _cleanup_close_ int netns = -1; |
| |
| /* So here's the thing: only AF_NETLINK sockets from the main network namespace will get |
| * hardware events. Let's check if ours is from there, and if not generate a debug message, |
| * since we cannot possibly work correctly otherwise. This is just a safety check to make |
| * things easier to debug. */ |
| |
| netns = ioctl(m->sock, SIOCGSKNS); |
| if (netns < 0) |
| log_debug_errno(errno, "sd-device-monitor: Unable to get network namespace of udev netlink socket, unable to determine if we are in host netns, ignoring: %m"); |
| else { |
| struct stat a, b; |
| |
| if (fstat(netns, &a) < 0) { |
| r = log_debug_errno(errno, "sd-device-monitor: Failed to stat netns of udev netlink socket: %m"); |
| goto fail; |
| } |
| |
| if (stat("/proc/1/ns/net", &b) < 0) { |
| if (ERRNO_IS_PRIVILEGE(errno)) |
| /* If we can't access PID1's netns info due to permissions, it's fine, this is a |
| * safety check only after all. */ |
| log_debug_errno(errno, "sd-device-monitor: No permission to stat PID1's netns, unable to determine if we are in host netns, ignoring: %m"); |
| else |
| log_debug_errno(errno, "sd-device-monitor: Failed to stat PID1's netns, ignoring: %m"); |
| |
| } else if (a.st_dev != b.st_dev || a.st_ino != b.st_ino) |
| log_debug("sd-device-monitor: Netlink socket we listen on is not from host netns, we won't see device events."); |
| } |
| } |
| |
| *ret = TAKE_PTR(m); |
| return 0; |
| |
| fail: |
| /* Let's unset the socket fd in the monitor object before we destroy it so that the fd passed in is |
| * not closed on failure. */ |
| if (fd >= 0) |
| m->sock = -1; |
| |
| return r; |
| } |
| |
| _public_ int sd_device_monitor_new(sd_device_monitor **ret) { |
| return device_monitor_new_full(ret, MONITOR_GROUP_UDEV, -1); |
| } |
| |
| _public_ int sd_device_monitor_stop(sd_device_monitor *m) { |
| assert_return(m, -EINVAL); |
| |
| m->event_source = sd_event_source_unref(m->event_source); |
| (void) device_monitor_disconnect(m); |
| |
| return 0; |
| } |
| |
| static int device_monitor_event_handler(sd_event_source *s, int fd, uint32_t revents, void *userdata) { |
| _cleanup_(sd_device_unrefp) sd_device *device = NULL; |
| sd_device_monitor *m = userdata; |
| |
| assert(m); |
| |
| if (device_monitor_receive_device(m, &device) <= 0) |
| return 0; |
| |
| if (m->callback) |
| return m->callback(m, device, m->userdata); |
| |
| return 0; |
| } |
| |
| _public_ int sd_device_monitor_start(sd_device_monitor *m, sd_device_monitor_handler_t callback, void *userdata) { |
| int r; |
| |
| assert_return(m, -EINVAL); |
| |
| if (!m->event) { |
| r = sd_device_monitor_attach_event(m, NULL); |
| if (r < 0) |
| return r; |
| } |
| |
| r = device_monitor_enable_receiving(m); |
| if (r < 0) |
| return r; |
| |
| m->callback = callback; |
| m->userdata = userdata; |
| |
| r = sd_event_add_io(m->event, &m->event_source, m->sock, EPOLLIN, device_monitor_event_handler, m); |
| if (r < 0) |
| return r; |
| |
| (void) sd_event_source_set_description(m->event_source, "sd-device-monitor"); |
| |
| return 0; |
| } |
| |
| _public_ int sd_device_monitor_detach_event(sd_device_monitor *m) { |
| assert_return(m, -EINVAL); |
| |
| (void) sd_device_monitor_stop(m); |
| m->event = sd_event_unref(m->event); |
| |
| return 0; |
| } |
| |
| _public_ int sd_device_monitor_attach_event(sd_device_monitor *m, sd_event *event) { |
| int r; |
| |
| assert_return(m, -EINVAL); |
| assert_return(!m->event, -EBUSY); |
| |
| if (event) |
| m->event = sd_event_ref(event); |
| else { |
| r = sd_event_default(&m->event); |
| if (r < 0) |
| return r; |
| } |
| |
| return 0; |
| } |
| |
| _public_ sd_event *sd_device_monitor_get_event(sd_device_monitor *m) { |
| assert_return(m, NULL); |
| |
| return m->event; |
| } |
| |
| _public_ sd_event_source *sd_device_monitor_get_event_source(sd_device_monitor *m) { |
| assert_return(m, NULL); |
| |
| return m->event_source; |
| } |
| |
| int device_monitor_enable_receiving(sd_device_monitor *m) { |
| int r; |
| |
| assert(m); |
| |
| r = sd_device_monitor_filter_update(m); |
| if (r < 0) |
| return log_debug_errno(r, "sd-device-monitor: Failed to update filter: %m"); |
| |
| if (!m->bound) { |
| /* enable receiving of sender credentials */ |
| r = setsockopt_int(m->sock, SOL_SOCKET, SO_PASSCRED, true); |
| if (r < 0) |
| return log_debug_errno(r, "sd-device-monitor: Failed to set socket option SO_PASSCRED: %m"); |
| |
| if (bind(m->sock, &m->snl.sa, sizeof(struct sockaddr_nl)) < 0) |
| return log_debug_errno(errno, "sd-device-monitor: Failed to bind monitoring socket: %m"); |
| |
| m->bound = true; |
| |
| r = monitor_set_nl_address(m); |
| if (r < 0) |
| return log_debug_errno(r, "sd-device-monitor: Failed to set address: %m"); |
| } |
| |
| return 0; |
| } |
| |
| static sd_device_monitor *device_monitor_free(sd_device_monitor *m) { |
| assert(m); |
| |
| (void) sd_device_monitor_detach_event(m); |
| |
| hashmap_free(m->subsystem_filter); |
| set_free(m->tag_filter); |
| hashmap_free(m->match_sysattr_filter); |
| hashmap_free(m->nomatch_sysattr_filter); |
| set_free(m->match_parent_filter); |
| set_free(m->nomatch_parent_filter); |
| |
| return mfree(m); |
| } |
| |
| DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_device_monitor, sd_device_monitor, device_monitor_free); |
| |
| static int check_subsystem_filter(sd_device_monitor *m, sd_device *device) { |
| const char *s, *subsystem, *d, *devtype = NULL; |
| int r; |
| |
| assert(m); |
| assert(device); |
| |
| if (hashmap_isempty(m->subsystem_filter)) |
| return true; |
| |
| r = sd_device_get_subsystem(device, &subsystem); |
| if (r < 0) |
| return r; |
| |
| r = sd_device_get_devtype(device, &devtype); |
| if (r < 0 && r != -ENOENT) |
| return r; |
| |
| HASHMAP_FOREACH_KEY(d, s, m->subsystem_filter) { |
| if (!streq(s, subsystem)) |
| continue; |
| |
| if (!d || streq_ptr(d, devtype)) |
| return true; |
| } |
| |
| return false; |
| } |
| |
| static bool check_tag_filter(sd_device_monitor *m, sd_device *device) { |
| const char *tag; |
| |
| assert(m); |
| assert(device); |
| |
| if (set_isempty(m->tag_filter)) |
| return true; |
| |
| SET_FOREACH(tag, m->tag_filter) |
| if (sd_device_has_tag(device, tag) > 0) |
| return true; |
| |
| return false; |
| } |
| |
| static int passes_filter(sd_device_monitor *m, sd_device *device) { |
| int r; |
| |
| assert(m); |
| assert(device); |
| |
| r = check_subsystem_filter(m, device); |
| if (r <= 0) |
| return r; |
| |
| if (!check_tag_filter(m, device)) |
| return false; |
| |
| if (!device_match_sysattr(device, m->match_sysattr_filter, m->nomatch_sysattr_filter)) |
| return false; |
| |
| return device_match_parent(device, m->match_parent_filter, m->nomatch_parent_filter); |
| } |
| |
| int device_monitor_receive_device(sd_device_monitor *m, sd_device **ret) { |
| _cleanup_(sd_device_unrefp) sd_device *device = NULL; |
| union { |
| monitor_netlink_header nlh; |
| char raw[8192]; |
| } buf; |
| struct iovec iov = { |
| .iov_base = &buf, |
| .iov_len = sizeof(buf) |
| }; |
| CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct ucred))) control; |
| union sockaddr_union snl; |
| struct msghdr smsg = { |
| .msg_iov = &iov, |
| .msg_iovlen = 1, |
| .msg_control = &control, |
| .msg_controllen = sizeof(control), |
| .msg_name = &snl, |
| .msg_namelen = sizeof(snl), |
| }; |
| struct cmsghdr *cmsg; |
| struct ucred *cred; |
| ssize_t buflen, bufpos; |
| bool is_initialized = false; |
| int r; |
| |
| assert(m); |
| assert(ret); |
| |
| buflen = recvmsg(m->sock, &smsg, 0); |
| if (buflen < 0) { |
| if (errno != EINTR) |
| log_debug_errno(errno, "sd-device-monitor: Failed to receive message: %m"); |
| return -errno; |
| } |
| |
| if (buflen < 32 || (smsg.msg_flags & MSG_TRUNC)) |
| return log_debug_errno(SYNTHETIC_ERRNO(EINVAL), |
| "sd-device-monitor: Invalid message length."); |
| |
| if (snl.nl.nl_groups == MONITOR_GROUP_NONE) { |
| /* unicast message, check if we trust the sender */ |
| if (m->snl_trusted_sender.nl.nl_pid == 0 || |
| snl.nl.nl_pid != m->snl_trusted_sender.nl.nl_pid) |
| return log_debug_errno(SYNTHETIC_ERRNO(EAGAIN), |
| "sd-device-monitor: Unicast netlink message ignored."); |
| |
| } else if (snl.nl.nl_groups == MONITOR_GROUP_KERNEL) { |
| if (snl.nl.nl_pid > 0) |
| return log_debug_errno(SYNTHETIC_ERRNO(EAGAIN), |
| "sd-device-monitor: Multicast kernel netlink message from PID %"PRIu32" ignored.", snl.nl.nl_pid); |
| } |
| |
| cmsg = CMSG_FIRSTHDR(&smsg); |
| if (!cmsg || cmsg->cmsg_type != SCM_CREDENTIALS) |
| return log_debug_errno(SYNTHETIC_ERRNO(EAGAIN), |
| "sd-device-monitor: No sender credentials received, message ignored."); |
| |
| cred = (struct ucred*) CMSG_DATA(cmsg); |
| if (cred->uid != 0) |
| return log_debug_errno(SYNTHETIC_ERRNO(EAGAIN), |
| "sd-device-monitor: Sender uid="UID_FMT", message ignored.", cred->uid); |
| |
| if (streq(buf.raw, "libudev")) { |
| /* udev message needs proper version magic */ |
| if (buf.nlh.magic != htobe32(UDEV_MONITOR_MAGIC)) |
| return log_debug_errno(SYNTHETIC_ERRNO(EAGAIN), |
| "sd-device-monitor: Invalid message signature (%x != %x)", |
| buf.nlh.magic, htobe32(UDEV_MONITOR_MAGIC)); |
| |
| if (buf.nlh.properties_off+32 > (size_t) buflen) |
| return log_debug_errno(SYNTHETIC_ERRNO(EAGAIN), |
| "sd-device-monitor: Invalid message length (%u > %zd)", |
| buf.nlh.properties_off+32, buflen); |
| |
| bufpos = buf.nlh.properties_off; |
| |
| /* devices received from udev are always initialized */ |
| is_initialized = true; |
| |
| } else { |
| /* kernel message with header */ |
| bufpos = strlen(buf.raw) + 1; |
| if ((size_t) bufpos < sizeof("a@/d") || bufpos >= buflen) |
| return log_debug_errno(SYNTHETIC_ERRNO(EAGAIN), |
| "sd-device-monitor: Invalid message length"); |
| |
| /* check message header */ |
| if (!strstr(buf.raw, "@/")) |
| return log_debug_errno(SYNTHETIC_ERRNO(EAGAIN), |
| "sd-device-monitor: Invalid message header"); |
| } |
| |
| r = device_new_from_nulstr(&device, (uint8_t*) &buf.raw[bufpos], buflen - bufpos); |
| if (r < 0) |
| return log_debug_errno(r, "sd-device-monitor: Failed to create device from received message: %m"); |
| |
| if (is_initialized) |
| device_set_is_initialized(device); |
| |
| /* Skip device, if it does not pass the current filter */ |
| r = passes_filter(m, device); |
| if (r < 0) |
| return log_device_debug_errno(device, r, "sd-device-monitor: Failed to check received device passing filter: %m"); |
| if (r == 0) |
| log_device_debug(device, "sd-device-monitor: Received device does not pass filter, ignoring"); |
| else |
| *ret = TAKE_PTR(device); |
| |
| return r; |
| } |
| |
| static uint32_t string_hash32(const char *str) { |
| return MurmurHash2(str, strlen(str), 0); |
| } |
| |
| /* Get a bunch of bit numbers out of the hash, and set the bits in our bit field */ |
| static uint64_t string_bloom64(const char *str) { |
| uint64_t bits = 0; |
| uint32_t hash = string_hash32(str); |
| |
| bits |= UINT64_C(1) << (hash & 63); |
| bits |= UINT64_C(1) << ((hash >> 6) & 63); |
| bits |= UINT64_C(1) << ((hash >> 12) & 63); |
| bits |= UINT64_C(1) << ((hash >> 18) & 63); |
| return bits; |
| } |
| |
| int device_monitor_send_device( |
| sd_device_monitor *m, |
| sd_device_monitor *destination, |
| sd_device *device) { |
| |
| monitor_netlink_header nlh = { |
| .prefix = "libudev", |
| .magic = htobe32(UDEV_MONITOR_MAGIC), |
| .header_size = sizeof nlh, |
| }; |
| struct iovec iov[2] = { |
| { .iov_base = &nlh, .iov_len = sizeof nlh }, |
| }; |
| struct msghdr smsg = { |
| .msg_iov = iov, |
| .msg_iovlen = 2, |
| }; |
| /* default destination for sending */ |
| union sockaddr_union default_destination = { |
| .nl.nl_family = AF_NETLINK, |
| .nl.nl_groups = MONITOR_GROUP_UDEV, |
| }; |
| uint64_t tag_bloom_bits; |
| const char *buf, *val; |
| ssize_t count; |
| size_t blen; |
| int r; |
| |
| assert(m); |
| assert(device); |
| |
| r = device_get_properties_nulstr(device, (const uint8_t **) &buf, &blen); |
| if (r < 0) |
| return log_device_debug_errno(device, r, "sd-device-monitor: Failed to get device properties: %m"); |
| if (blen < 32) |
| log_device_debug_errno(device, SYNTHETIC_ERRNO(EINVAL), |
| "sd-device-monitor: Length of device property nulstr is too small to contain valid device information"); |
| |
| /* fill in versioned header */ |
| r = sd_device_get_subsystem(device, &val); |
| if (r < 0) |
| return log_device_debug_errno(device, r, "sd-device-monitor: Failed to get device subsystem: %m"); |
| nlh.filter_subsystem_hash = htobe32(string_hash32(val)); |
| |
| if (sd_device_get_devtype(device, &val) >= 0) |
| nlh.filter_devtype_hash = htobe32(string_hash32(val)); |
| |
| /* add tag bloom filter */ |
| tag_bloom_bits = 0; |
| FOREACH_DEVICE_TAG(device, val) |
| tag_bloom_bits |= string_bloom64(val); |
| |
| if (tag_bloom_bits > 0) { |
| nlh.filter_tag_bloom_hi = htobe32(tag_bloom_bits >> 32); |
| nlh.filter_tag_bloom_lo = htobe32(tag_bloom_bits & 0xffffffff); |
| } |
| |
| /* add properties list */ |
| nlh.properties_off = iov[0].iov_len; |
| nlh.properties_len = blen; |
| iov[1] = IOVEC_MAKE((char*) buf, blen); |
| |
| /* |
| * Use custom address for target, or the default one. |
| * |
| * If we send to a multicast group, we will get |
| * ECONNREFUSED, which is expected. |
| */ |
| smsg.msg_name = destination ? &destination->snl : &default_destination; |
| smsg.msg_namelen = sizeof(struct sockaddr_nl); |
| count = sendmsg(m->sock, &smsg, 0); |
| if (count < 0) { |
| if (!destination && errno == ECONNREFUSED) { |
| log_device_debug(device, "sd-device-monitor: Passed to netlink monitor"); |
| return 0; |
| } else |
| return log_device_debug_errno(device, errno, "sd-device-monitor: Failed to send device to netlink monitor: %m"); |
| } |
| |
| log_device_debug(device, "sd-device-monitor: Passed %zi byte to netlink monitor", count); |
| return count; |
| } |
| |
| static void bpf_stmt(struct sock_filter *ins, unsigned *i, |
| unsigned short code, unsigned data) { |
| ins[(*i)++] = (struct sock_filter) { |
| .code = code, |
| .k = data, |
| }; |
| } |
| |
| static void bpf_jmp(struct sock_filter *ins, unsigned *i, |
| unsigned short code, unsigned data, |
| unsigned short jt, unsigned short jf) { |
| ins[(*i)++] = (struct sock_filter) { |
| .code = code, |
| .jt = jt, |
| .jf = jf, |
| .k = data, |
| }; |
| } |
| |
| _public_ int sd_device_monitor_filter_update(sd_device_monitor *m) { |
| struct sock_filter ins[512] = {}; |
| struct sock_fprog filter; |
| const char *subsystem, *devtype, *tag; |
| unsigned i = 0; |
| |
| assert_return(m, -EINVAL); |
| |
| if (m->filter_uptodate) |
| return 0; |
| |
| if (m->snl.nl.nl_groups == MONITOR_GROUP_KERNEL || |
| (hashmap_isempty(m->subsystem_filter) && |
| set_isempty(m->tag_filter))) { |
| m->filter_uptodate = true; |
| return 0; |
| } |
| |
| /* load magic in A */ |
| bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(monitor_netlink_header, magic)); |
| /* jump if magic matches */ |
| bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, UDEV_MONITOR_MAGIC, 1, 0); |
| /* wrong magic, pass packet */ |
| bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff); |
| |
| if (!set_isempty(m->tag_filter)) { |
| int tag_matches = set_size(m->tag_filter); |
| |
| /* add all tags matches */ |
| SET_FOREACH(tag, m->tag_filter) { |
| uint64_t tag_bloom_bits = string_bloom64(tag); |
| uint32_t tag_bloom_hi = tag_bloom_bits >> 32; |
| uint32_t tag_bloom_lo = tag_bloom_bits & 0xffffffff; |
| |
| /* load device bloom bits in A */ |
| bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(monitor_netlink_header, filter_tag_bloom_hi)); |
| /* clear bits (tag bits & bloom bits) */ |
| bpf_stmt(ins, &i, BPF_ALU|BPF_AND|BPF_K, tag_bloom_hi); |
| /* jump to next tag if it does not match */ |
| bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, tag_bloom_hi, 0, 3); |
| |
| /* load device bloom bits in A */ |
| bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(monitor_netlink_header, filter_tag_bloom_lo)); |
| /* clear bits (tag bits & bloom bits) */ |
| bpf_stmt(ins, &i, BPF_ALU|BPF_AND|BPF_K, tag_bloom_lo); |
| /* jump behind end of tag match block if tag matches */ |
| tag_matches--; |
| bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, tag_bloom_lo, 1 + (tag_matches * 6), 0); |
| } |
| |
| /* nothing matched, drop packet */ |
| bpf_stmt(ins, &i, BPF_RET|BPF_K, 0); |
| } |
| |
| /* add all subsystem matches */ |
| if (!hashmap_isempty(m->subsystem_filter)) { |
| HASHMAP_FOREACH_KEY(devtype, subsystem, m->subsystem_filter) { |
| uint32_t hash = string_hash32(subsystem); |
| |
| /* load device subsystem value in A */ |
| bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(monitor_netlink_header, filter_subsystem_hash)); |
| if (!devtype) { |
| /* jump if subsystem does not match */ |
| bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 1); |
| } else { |
| /* jump if subsystem does not match */ |
| bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 3); |
| /* load device devtype value in A */ |
| bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(monitor_netlink_header, filter_devtype_hash)); |
| /* jump if value does not match */ |
| hash = string_hash32(devtype); |
| bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 1); |
| } |
| |
| /* matched, pass packet */ |
| bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff); |
| |
| if (i+1 >= ELEMENTSOF(ins)) |
| return -E2BIG; |
| } |
| |
| /* nothing matched, drop packet */ |
| bpf_stmt(ins, &i, BPF_RET|BPF_K, 0); |
| } |
| |
| /* matched, pass packet */ |
| bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff); |
| |
| /* install filter */ |
| filter = (struct sock_fprog) { |
| .len = i, |
| .filter = ins, |
| }; |
| if (setsockopt(m->sock, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter)) < 0) |
| return -errno; |
| |
| m->filter_uptodate = true; |
| return 0; |
| } |
| |
| _public_ int sd_device_monitor_filter_add_match_subsystem_devtype(sd_device_monitor *m, const char *subsystem, const char *devtype) { |
| int r; |
| |
| assert_return(m, -EINVAL); |
| assert_return(subsystem, -EINVAL); |
| |
| /* Do not use string_has_ops_free_free or hashmap_put_strdup() here, as this may be called |
| * multiple times with the same subsystem but different devtypes. */ |
| r = hashmap_put_strdup_full(&m->subsystem_filter, &trivial_hash_ops_free_free, subsystem, devtype); |
| if (r <= 0) |
| return r; |
| |
| m->filter_uptodate = false; |
| return r; |
| } |
| |
| _public_ int sd_device_monitor_filter_add_match_tag(sd_device_monitor *m, const char *tag) { |
| int r; |
| |
| assert_return(m, -EINVAL); |
| assert_return(tag, -EINVAL); |
| |
| r = set_put_strdup(&m->tag_filter, tag); |
| if (r <= 0) |
| return r; |
| |
| m->filter_uptodate = false; |
| return r; |
| } |
| |
| _public_ int sd_device_monitor_filter_add_match_sysattr(sd_device_monitor *m, const char *sysattr, const char *value, int match) { |
| Hashmap **hashmap; |
| |
| assert_return(m, -EINVAL); |
| assert_return(sysattr, -EINVAL); |
| |
| if (match) |
| hashmap = &m->match_sysattr_filter; |
| else |
| hashmap = &m->nomatch_sysattr_filter; |
| |
| /* TODO: unset m->filter_uptodate on success when we support this filter on BPF. */ |
| return hashmap_put_strdup_full(hashmap, &trivial_hash_ops_free_free, sysattr, value); |
| } |
| |
| _public_ int sd_device_monitor_filter_add_match_parent(sd_device_monitor *m, sd_device *device, int match) { |
| const char *syspath; |
| Set **set; |
| int r; |
| |
| assert_return(m, -EINVAL); |
| assert_return(device, -EINVAL); |
| |
| r = sd_device_get_syspath(device, &syspath); |
| if (r < 0) |
| return r; |
| |
| if (match) |
| set = &m->match_parent_filter; |
| else |
| set = &m->nomatch_parent_filter; |
| |
| /* TODO: unset m->filter_uptodate on success when we support this filter on BPF. */ |
| return set_put_strdup(set, syspath); |
| } |
| |
| _public_ int sd_device_monitor_filter_remove(sd_device_monitor *m) { |
| static const struct sock_fprog filter = { 0, NULL }; |
| |
| assert_return(m, -EINVAL); |
| |
| m->subsystem_filter = hashmap_free(m->subsystem_filter); |
| m->tag_filter = set_free(m->tag_filter); |
| m->match_sysattr_filter = hashmap_free(m->match_sysattr_filter); |
| m->nomatch_sysattr_filter = hashmap_free(m->nomatch_sysattr_filter); |
| m->match_parent_filter = set_free(m->match_parent_filter); |
| m->nomatch_parent_filter = set_free(m->nomatch_parent_filter); |
| |
| if (setsockopt(m->sock, SOL_SOCKET, SO_DETACH_FILTER, &filter, sizeof(filter)) < 0) |
| return -errno; |
| |
| m->filter_uptodate = true; |
| return 0; |
| } |
