| /* |
| * Copyright (C) 2022 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #define LOG_TAG "TcUtils" |
| |
| #include "tcutils/tcutils.h" |
| |
| #include "kernelversion.h" |
| #include "scopeguard.h" |
| |
| #include <android/log.h> |
| #include <arpa/inet.h> |
| #include <cerrno> |
| #include <cstring> |
| #include <libgen.h> |
| #include <linux/if_arp.h> |
| #include <linux/if_ether.h> |
| #include <linux/netlink.h> |
| #include <linux/pkt_cls.h> |
| #include <linux/pkt_sched.h> |
| #include <linux/rtnetlink.h> |
| #include <net/if.h> |
| #include <stdarg.h> |
| #include <stdio.h> |
| #include <sys/socket.h> |
| #include <unistd.h> |
| #include <utility> |
| |
| #define BPF_FD_JUST_USE_INT |
| #include <BpfSyscallWrappers.h> |
| #undef BPF_FD_JUST_USE_INT |
| |
| // The maximum length of TCA_BPF_NAME. Sync from net/sched/cls_bpf.c. |
| #define CLS_BPF_NAME_LEN 256 |
| |
| // Classifier name. See cls_bpf_ops in net/sched/cls_bpf.c. |
| #define CLS_BPF_KIND_NAME "bpf" |
| |
| namespace android { |
| namespace { |
| |
| void logError(const char *fmt...) { |
| va_list args; |
| va_start(args, fmt); |
| __android_log_vprint(ANDROID_LOG_ERROR, LOG_TAG, fmt, args); |
| va_end(args); |
| } |
| |
| const sockaddr_nl KERNEL_NLADDR = {AF_NETLINK, 0, 0, 0}; |
| const uint16_t NETLINK_REQUEST_FLAGS = NLM_F_REQUEST | NLM_F_ACK; |
| |
| int sendAndProcessNetlinkResponse(const void *req, int len) { |
| // TODO: use unique_fd instead of ScopeGuard |
| int fd = socket(AF_NETLINK, SOCK_RAW | SOCK_CLOEXEC, NETLINK_ROUTE); |
| if (fd == -1) { |
| int error = errno; |
| logError("socket(AF_NETLINK, SOCK_RAW | SOCK_CLOEXEC, NETLINK_ROUTE): %d", |
| error); |
| return -error; |
| } |
| auto scopeGuard = base::make_scope_guard([fd] { close(fd); }); |
| |
| static constexpr int on = 1; |
| if (setsockopt(fd, SOL_NETLINK, NETLINK_CAP_ACK, &on, sizeof(on))) { |
| int error = errno; |
| logError("setsockopt(fd, SOL_NETLINK, NETLINK_CAP_ACK, 1): %d", error); |
| return -error; |
| } |
| |
| // this is needed to get valid strace netlink parsing, it allocates the pid |
| if (bind(fd, (const struct sockaddr *)&KERNEL_NLADDR, |
| sizeof(KERNEL_NLADDR))) { |
| int error = errno; |
| logError("bind(fd, {AF_NETLINK, 0, 0}: %d)", error); |
| return -error; |
| } |
| |
| // we do not want to receive messages from anyone besides the kernel |
| if (connect(fd, (const struct sockaddr *)&KERNEL_NLADDR, |
| sizeof(KERNEL_NLADDR))) { |
| int error = errno; |
| logError("connect(fd, {AF_NETLINK, 0, 0}): %d", error); |
| return -error; |
| } |
| |
| int rv = send(fd, req, len, 0); |
| |
| if (rv == -1) { |
| int error = errno; |
| logError("send(fd, req, len, 0) failed: %d", error); |
| return -error; |
| } |
| |
| if (rv != len) { |
| logError("send(fd, req, len = %d, 0) returned invalid message size %d", len, |
| rv); |
| return -EMSGSIZE; |
| } |
| |
| struct { |
| nlmsghdr h; |
| nlmsgerr e; |
| char buf[256]; |
| } resp = {}; |
| |
| rv = recv(fd, &resp, sizeof(resp), MSG_TRUNC); |
| |
| if (rv == -1) { |
| int error = errno; |
| logError("recv() failed: %d", error); |
| return -error; |
| } |
| |
| if (rv < (int)NLMSG_SPACE(sizeof(struct nlmsgerr))) { |
| logError("recv() returned short packet: %d", rv); |
| return -EBADMSG; |
| } |
| |
| if (resp.h.nlmsg_len != (unsigned)rv) { |
| logError("recv() returned invalid header length: %d != %d", |
| resp.h.nlmsg_len, rv); |
| return -EBADMSG; |
| } |
| |
| if (resp.h.nlmsg_type != NLMSG_ERROR) { |
| logError("recv() did not return NLMSG_ERROR message: %d", |
| resp.h.nlmsg_type); |
| return -ENOMSG; |
| } |
| |
| if (resp.e.error) { |
| logError("NLMSG_ERROR message return error: %d", resp.e.error); |
| } |
| return resp.e.error; // returns 0 on success |
| } |
| |
| int hardwareAddressType(const char *interface) { |
| int fd = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, 0); |
| if (fd < 0) |
| return -errno; |
| auto scopeGuard = base::make_scope_guard([fd] { close(fd); }); |
| |
| struct ifreq ifr = {}; |
| // We use strncpy() instead of strlcpy() since kernel has to be able |
| // to handle non-zero terminated junk passed in by userspace anyway, |
| // and this way too long interface names (more than IFNAMSIZ-1 = 15 |
| // characters plus terminating NULL) will not get truncated to 15 |
| // characters and zero-terminated and thus potentially erroneously |
| // match a truncated interface if one were to exist. |
| strncpy(ifr.ifr_name, interface, sizeof(ifr.ifr_name)); |
| |
| if (ioctl(fd, SIOCGIFHWADDR, &ifr, sizeof(ifr))) { |
| return -errno; |
| } |
| return ifr.ifr_hwaddr.sa_family; |
| } |
| |
| } // namespace |
| |
| int isEthernet(const char *iface, bool &isEthernet) { |
| int rv = hardwareAddressType(iface); |
| if (rv < 0) { |
| logError("Get hardware address type of interface %s failed: %s", iface, |
| strerror(-rv)); |
| return rv; |
| } |
| |
| // Backwards compatibility with pre-GKI kernels that use various custom |
| // ARPHRD_* for their cellular interface |
| switch (rv) { |
| // ARPHRD_PUREIP on at least some Mediatek Android kernels |
| // example: wembley with 4.19 kernel |
| case 520: |
| // in Linux 4.14+ rmnet support was upstreamed and ARHRD_RAWIP became 519, |
| // but it is 530 on at least some Qualcomm Android 4.9 kernels with rmnet |
| // example: Pixel 3 family |
| case 530: |
| // >5.4 kernels are GKI2.0 and thus upstream compatible, however 5.10 |
| // shipped with Android S, so (for safety) let's limit ourselves to |
| // >5.10, ie. 5.11+ as a guarantee we're on Android T+ and thus no |
| // longer need this non-upstream compatibility logic |
| static bool is_pre_5_11_kernel = !isAtLeastKernelVersion(5, 11, 0); |
| if (is_pre_5_11_kernel) |
| return false; |
| } |
| |
| switch (rv) { |
| case ARPHRD_ETHER: |
| isEthernet = true; |
| return 0; |
| case ARPHRD_NONE: |
| case ARPHRD_PPP: |
| case ARPHRD_RAWIP: |
| isEthernet = false; |
| return 0; |
| default: |
| logError("Unknown hardware address type %d on interface %s", rv, iface); |
| return -EAFNOSUPPORT; |
| } |
| } |
| |
| // ADD: nlMsgType=RTM_NEWQDISC nlMsgFlags=NLM_F_EXCL|NLM_F_CREATE |
| // REPLACE: nlMsgType=RTM_NEWQDISC nlMsgFlags=NLM_F_CREATE|NLM_F_REPLACE |
| // DEL: nlMsgType=RTM_DELQDISC nlMsgFlags=0 |
| int doTcQdiscClsact(int ifIndex, uint16_t nlMsgType, uint16_t nlMsgFlags) { |
| // This is the name of the qdisc we are attaching. |
| // Some hoop jumping to make this compile time constant with known size, |
| // so that the structure declaration is well defined at compile time. |
| #define CLSACT "clsact" |
| // sizeof() includes the terminating NULL |
| static constexpr size_t ASCIIZ_LEN_CLSACT = sizeof(CLSACT); |
| |
| const struct { |
| nlmsghdr n; |
| tcmsg t; |
| struct { |
| nlattr attr; |
| char str[NLMSG_ALIGN(ASCIIZ_LEN_CLSACT)]; |
| } kind; |
| } req = { |
| .n = |
| { |
| .nlmsg_len = sizeof(req), |
| .nlmsg_type = nlMsgType, |
| .nlmsg_flags = |
| static_cast<__u16>(NETLINK_REQUEST_FLAGS | nlMsgFlags), |
| }, |
| .t = |
| { |
| .tcm_family = AF_UNSPEC, |
| .tcm_ifindex = ifIndex, |
| .tcm_handle = TC_H_MAKE(TC_H_CLSACT, 0), |
| .tcm_parent = TC_H_CLSACT, |
| }, |
| .kind = |
| { |
| .attr = |
| { |
| .nla_len = NLA_HDRLEN + ASCIIZ_LEN_CLSACT, |
| .nla_type = TCA_KIND, |
| }, |
| .str = CLSACT, |
| }, |
| }; |
| #undef CLSACT |
| |
| return sendAndProcessNetlinkResponse(&req, sizeof(req)); |
| } |
| |
| // tc filter add dev .. in/egress prio 1 protocol ipv6/ip bpf object-pinned |
| // /sys/fs/bpf/... direct-action |
| int tcAddBpfFilter(int ifIndex, bool ingress, uint16_t prio, uint16_t proto, |
| const char *bpfProgPath) { |
| const int bpfFd = bpf::retrieveProgram(bpfProgPath); |
| if (bpfFd == -1) { |
| logError("retrieveProgram failed: %d", errno); |
| return -errno; |
| } |
| auto scopeGuard = base::make_scope_guard([bpfFd] { close(bpfFd); }); |
| |
| struct { |
| nlmsghdr n; |
| tcmsg t; |
| struct { |
| nlattr attr; |
| // The maximum classifier name length is defined in |
| // tcf_proto_ops in include/net/sch_generic.h. |
| char str[NLMSG_ALIGN(sizeof(CLS_BPF_KIND_NAME))]; |
| } kind; |
| struct { |
| nlattr attr; |
| struct { |
| nlattr attr; |
| __u32 u32; |
| } fd; |
| struct { |
| nlattr attr; |
| char str[NLMSG_ALIGN(CLS_BPF_NAME_LEN)]; |
| } name; |
| struct { |
| nlattr attr; |
| __u32 u32; |
| } flags; |
| } options; |
| } req = { |
| .n = |
| { |
| .nlmsg_len = sizeof(req), |
| .nlmsg_type = RTM_NEWTFILTER, |
| .nlmsg_flags = NETLINK_REQUEST_FLAGS | NLM_F_EXCL | NLM_F_CREATE, |
| }, |
| .t = |
| { |
| .tcm_family = AF_UNSPEC, |
| .tcm_ifindex = ifIndex, |
| .tcm_handle = TC_H_UNSPEC, |
| .tcm_parent = TC_H_MAKE(TC_H_CLSACT, ingress ? TC_H_MIN_INGRESS |
| : TC_H_MIN_EGRESS), |
| .tcm_info = |
| static_cast<__u32>((static_cast<uint16_t>(prio) << 16) | |
| htons(static_cast<uint16_t>(proto))), |
| }, |
| .kind = |
| { |
| .attr = |
| { |
| .nla_len = sizeof(req.kind), |
| .nla_type = TCA_KIND, |
| }, |
| .str = CLS_BPF_KIND_NAME, |
| }, |
| .options = |
| { |
| .attr = |
| { |
| .nla_len = sizeof(req.options), |
| .nla_type = NLA_F_NESTED | TCA_OPTIONS, |
| }, |
| .fd = |
| { |
| .attr = |
| { |
| .nla_len = sizeof(req.options.fd), |
| .nla_type = TCA_BPF_FD, |
| }, |
| .u32 = static_cast<__u32>(bpfFd), |
| }, |
| .name = |
| { |
| .attr = |
| { |
| .nla_len = sizeof(req.options.name), |
| .nla_type = TCA_BPF_NAME, |
| }, |
| // Visible via 'tc filter show', but |
| // is overwritten by strncpy below |
| .str = "placeholder", |
| }, |
| .flags = |
| { |
| .attr = |
| { |
| .nla_len = sizeof(req.options.flags), |
| .nla_type = TCA_BPF_FLAGS, |
| }, |
| .u32 = TCA_BPF_FLAG_ACT_DIRECT, |
| }, |
| }, |
| }; |
| |
| snprintf(req.options.name.str, sizeof(req.options.name.str), "%s:[*fsobj]", |
| basename(bpfProgPath)); |
| |
| int error = sendAndProcessNetlinkResponse(&req, sizeof(req)); |
| return error; |
| } |
| |
| // tc filter del dev .. in/egress prio .. protocol .. |
| int tcDeleteFilter(int ifIndex, bool ingress, uint16_t prio, uint16_t proto) { |
| const struct { |
| nlmsghdr n; |
| tcmsg t; |
| } req = { |
| .n = |
| { |
| .nlmsg_len = sizeof(req), |
| .nlmsg_type = RTM_DELTFILTER, |
| .nlmsg_flags = NETLINK_REQUEST_FLAGS, |
| }, |
| .t = |
| { |
| .tcm_family = AF_UNSPEC, |
| .tcm_ifindex = ifIndex, |
| .tcm_handle = TC_H_UNSPEC, |
| .tcm_parent = TC_H_MAKE(TC_H_CLSACT, ingress ? TC_H_MIN_INGRESS |
| : TC_H_MIN_EGRESS), |
| .tcm_info = |
| static_cast<__u32>((static_cast<uint16_t>(prio) << 16) | |
| htons(static_cast<uint16_t>(proto))), |
| }, |
| }; |
| |
| return sendAndProcessNetlinkResponse(&req, sizeof(req)); |
| } |
| |
| } // namespace android |