diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index c9fdf6f57913..32c553556bbd 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -553,6 +553,36 @@ static inline bool cgroup_is_descendant(struct cgroup *cgrp, return cgrp->ancestor_ids[ancestor->level] == ancestor->id; } +/** + * cgroup_ancestor - find ancestor of cgroup + * @cgrp: cgroup to find ancestor of + * @ancestor_level: level of ancestor to find starting from root + * + * Find ancestor of cgroup at specified level starting from root if it exists + * and return pointer to it. Return NULL if @cgrp doesn't have ancestor at + * @ancestor_level. + * + * This function is safe to call as long as @cgrp is accessible. + */ +static inline struct cgroup *cgroup_ancestor(struct cgroup *cgrp, + int ancestor_level) +{ + struct cgroup *ptr; + + if (cgrp->level < ancestor_level) + return NULL; + + for (ptr = cgrp; + ptr && ptr->level > ancestor_level; + ptr = cgroup_parent(ptr)) + ; + + if (ptr && ptr->level == ancestor_level) + return ptr; + + return NULL; +} + /** * task_under_cgroup_hierarchy - test task's membership of cgroup ancestry * @task: the task to be tested diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 3102a2a23c31..66917a4eba27 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -2093,6 +2093,24 @@ union bpf_attr { * Return * The id is returned or 0 in case the id could not be retrieved. * + * u64 bpf_skb_ancestor_cgroup_id(struct sk_buff *skb, int ancestor_level) + * Description + * Return id of cgroup v2 that is ancestor of cgroup associated + * with the *skb* at the *ancestor_level*. The root cgroup is at + * *ancestor_level* zero and each step down the hierarchy + * increments the level. If *ancestor_level* == level of cgroup + * associated with *skb*, then return value will be same as that + * of **bpf_skb_cgroup_id**\ (). + * + * The helper is useful to implement policies based on cgroups + * that are upper in hierarchy than immediate cgroup associated + * with *skb*. + * + * The format of returned id and helper limitations are same as in + * **bpf_skb_cgroup_id**\ (). + * Return + * The id is returned or 0 in case the id could not be retrieved. + * * u64 bpf_get_current_cgroup_id(void) * Return * A 64-bit integer containing the current cgroup id based @@ -2207,7 +2225,8 @@ union bpf_attr { FN(skb_cgroup_id), \ FN(get_current_cgroup_id), \ FN(get_local_storage), \ - FN(sk_select_reuseport), + FN(sk_select_reuseport), \ + FN(skb_ancestor_cgroup_id), /* integer value in 'imm' field of BPF_CALL instruction selects which helper * function eBPF program intends to call diff --git a/net/core/filter.c b/net/core/filter.c index 22906b31d43f..15b9d2df92ca 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -3778,6 +3778,32 @@ static const struct bpf_func_proto bpf_skb_cgroup_id_proto = { .ret_type = RET_INTEGER, .arg1_type = ARG_PTR_TO_CTX, }; + +BPF_CALL_2(bpf_skb_ancestor_cgroup_id, const struct sk_buff *, skb, int, + ancestor_level) +{ + struct sock *sk = skb_to_full_sk(skb); + struct cgroup *ancestor; + struct cgroup *cgrp; + + if (!sk || !sk_fullsock(sk)) + return 0; + + cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data); + ancestor = cgroup_ancestor(cgrp, ancestor_level); + if (!ancestor) + return 0; + + return ancestor->kn->id.id; +} + +static const struct bpf_func_proto bpf_skb_ancestor_cgroup_id_proto = { + .func = bpf_skb_ancestor_cgroup_id, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_CTX, + .arg2_type = ARG_ANYTHING, +}; #endif static unsigned long bpf_xdp_copy(void *dst_buff, const void *src_buff, @@ -4966,6 +4992,8 @@ tc_cls_act_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) #ifdef CONFIG_SOCK_CGROUP_DATA case BPF_FUNC_skb_cgroup_id: return &bpf_skb_cgroup_id_proto; + case BPF_FUNC_skb_ancestor_cgroup_id: + return &bpf_skb_ancestor_cgroup_id_proto; #endif default: return bpf_base_func_proto(func_id); diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 3102a2a23c31..66917a4eba27 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -2093,6 +2093,24 @@ union bpf_attr { * Return * The id is returned or 0 in case the id could not be retrieved. * + * u64 bpf_skb_ancestor_cgroup_id(struct sk_buff *skb, int ancestor_level) + * Description + * Return id of cgroup v2 that is ancestor of cgroup associated + * with the *skb* at the *ancestor_level*. The root cgroup is at + * *ancestor_level* zero and each step down the hierarchy + * increments the level. If *ancestor_level* == level of cgroup + * associated with *skb*, then return value will be same as that + * of **bpf_skb_cgroup_id**\ (). + * + * The helper is useful to implement policies based on cgroups + * that are upper in hierarchy than immediate cgroup associated + * with *skb*. + * + * The format of returned id and helper limitations are same as in + * **bpf_skb_cgroup_id**\ (). + * Return + * The id is returned or 0 in case the id could not be retrieved. + * * u64 bpf_get_current_cgroup_id(void) * Return * A 64-bit integer containing the current cgroup id based @@ -2207,7 +2225,8 @@ union bpf_attr { FN(skb_cgroup_id), \ FN(get_current_cgroup_id), \ FN(get_local_storage), \ - FN(sk_select_reuseport), + FN(sk_select_reuseport), \ + FN(skb_ancestor_cgroup_id), /* integer value in 'imm' field of BPF_CALL instruction selects which helper * function eBPF program intends to call diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index daed162043c2..fff7fb1285fc 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -34,7 +34,8 @@ TEST_GEN_FILES = test_pkt_access.o test_xdp.o test_l4lb.o test_tcp_estats.o test test_btf_haskv.o test_btf_nokv.o test_sockmap_kern.o test_tunnel_kern.o \ test_get_stack_rawtp.o test_sockmap_kern.o test_sockhash_kern.o \ test_lwt_seg6local.o sendmsg4_prog.o sendmsg6_prog.o test_lirc_mode2_kern.o \ - get_cgroup_id_kern.o socket_cookie_prog.o test_select_reuseport_kern.o + get_cgroup_id_kern.o socket_cookie_prog.o test_select_reuseport_kern.o \ + test_skb_cgroup_id_kern.o # Order correspond to 'make run_tests' order TEST_PROGS := test_kmod.sh \ @@ -45,10 +46,11 @@ TEST_PROGS := test_kmod.sh \ test_sock_addr.sh \ test_tunnel.sh \ test_lwt_seg6local.sh \ - test_lirc_mode2.sh + test_lirc_mode2.sh \ + test_skb_cgroup_id.sh # Compile but not part of 'make run_tests' -TEST_GEN_PROGS_EXTENDED = test_libbpf_open test_sock_addr +TEST_GEN_PROGS_EXTENDED = test_libbpf_open test_sock_addr test_skb_cgroup_id_user include ../lib.mk @@ -59,6 +61,7 @@ $(TEST_GEN_PROGS): $(BPFOBJ) $(TEST_GEN_PROGS_EXTENDED): $(OUTPUT)/libbpf.a $(OUTPUT)/test_dev_cgroup: cgroup_helpers.c +$(OUTPUT)/test_skb_cgroup_id_user: cgroup_helpers.c $(OUTPUT)/test_sock: cgroup_helpers.c $(OUTPUT)/test_sock_addr: cgroup_helpers.c $(OUTPUT)/test_socket_cookie: cgroup_helpers.c diff --git a/tools/testing/selftests/bpf/bpf_helpers.h b/tools/testing/selftests/bpf/bpf_helpers.h index 5c32266c2c38..e4be7730222d 100644 --- a/tools/testing/selftests/bpf/bpf_helpers.h +++ b/tools/testing/selftests/bpf/bpf_helpers.h @@ -139,6 +139,10 @@ static unsigned long long (*bpf_get_current_cgroup_id)(void) = (void *) BPF_FUNC_get_current_cgroup_id; static void *(*bpf_get_local_storage)(void *map, unsigned long long flags) = (void *) BPF_FUNC_get_local_storage; +static unsigned long long (*bpf_skb_cgroup_id)(void *ctx) = + (void *) BPF_FUNC_skb_cgroup_id; +static unsigned long long (*bpf_skb_ancestor_cgroup_id)(void *ctx, int level) = + (void *) BPF_FUNC_skb_ancestor_cgroup_id; /* llvm builtin functions that eBPF C program may use to * emit BPF_LD_ABS and BPF_LD_IND instructions diff --git a/tools/testing/selftests/bpf/test_skb_cgroup_id.sh b/tools/testing/selftests/bpf/test_skb_cgroup_id.sh new file mode 100755 index 000000000000..42544a969abc --- /dev/null +++ b/tools/testing/selftests/bpf/test_skb_cgroup_id.sh @@ -0,0 +1,62 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 +# Copyright (c) 2018 Facebook + +set -eu + +wait_for_ip() +{ + local _i + echo -n "Wait for testing link-local IP to become available " + for _i in $(seq ${MAX_PING_TRIES}); do + echo -n "." + if ping -6 -q -c 1 -W 1 ff02::1%${TEST_IF} >/dev/null 2>&1; then + echo " OK" + return + fi + sleep 1 + done + echo 1>&2 "ERROR: Timeout waiting for test IP to become available." + exit 1 +} + +setup() +{ + # Create testing interfaces not to interfere with current environment. + ip link add dev ${TEST_IF} type veth peer name ${TEST_IF_PEER} + ip link set ${TEST_IF} up + ip link set ${TEST_IF_PEER} up + + wait_for_ip + + tc qdisc add dev ${TEST_IF} clsact + tc filter add dev ${TEST_IF} egress bpf obj ${BPF_PROG_OBJ} \ + sec ${BPF_PROG_SECTION} da + + BPF_PROG_ID=$(tc filter show dev ${TEST_IF} egress | \ + awk '/ id / {sub(/.* id /, "", $0); print($1)}') +} + +cleanup() +{ + ip link del ${TEST_IF} 2>/dev/null || : + ip link del ${TEST_IF_PEER} 2>/dev/null || : +} + +main() +{ + trap cleanup EXIT 2 3 6 15 + setup + ${PROG} ${TEST_IF} ${BPF_PROG_ID} +} + +DIR=$(dirname $0) +TEST_IF="test_cgid_1" +TEST_IF_PEER="test_cgid_2" +MAX_PING_TRIES=5 +BPF_PROG_OBJ="${DIR}/test_skb_cgroup_id_kern.o" +BPF_PROG_SECTION="cgroup_id_logger" +BPF_PROG_ID=0 +PROG="${DIR}/test_skb_cgroup_id_user" + +main diff --git a/tools/testing/selftests/bpf/test_skb_cgroup_id_kern.c b/tools/testing/selftests/bpf/test_skb_cgroup_id_kern.c new file mode 100644 index 000000000000..68cf9829f5a7 --- /dev/null +++ b/tools/testing/selftests/bpf/test_skb_cgroup_id_kern.c @@ -0,0 +1,47 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) 2018 Facebook + +#include +#include + +#include + +#include "bpf_helpers.h" + +#define NUM_CGROUP_LEVELS 4 + +struct bpf_map_def SEC("maps") cgroup_ids = { + .type = BPF_MAP_TYPE_ARRAY, + .key_size = sizeof(__u32), + .value_size = sizeof(__u64), + .max_entries = NUM_CGROUP_LEVELS, +}; + +static __always_inline void log_nth_level(struct __sk_buff *skb, __u32 level) +{ + __u64 id; + + /* [1] &level passed to external function that may change it, it's + * incompatible with loop unroll. + */ + id = bpf_skb_ancestor_cgroup_id(skb, level); + bpf_map_update_elem(&cgroup_ids, &level, &id, 0); +} + +SEC("cgroup_id_logger") +int log_cgroup_id(struct __sk_buff *skb) +{ + /* Loop unroll can't be used here due to [1]. Unrolling manually. + * Number of calls should be in sync with NUM_CGROUP_LEVELS. + */ + log_nth_level(skb, 0); + log_nth_level(skb, 1); + log_nth_level(skb, 2); + log_nth_level(skb, 3); + + return TC_ACT_OK; +} + +int _version SEC("version") = 1; + +char _license[] SEC("license") = "GPL"; diff --git a/tools/testing/selftests/bpf/test_skb_cgroup_id_user.c b/tools/testing/selftests/bpf/test_skb_cgroup_id_user.c new file mode 100644 index 000000000000..c121cc59f314 --- /dev/null +++ b/tools/testing/selftests/bpf/test_skb_cgroup_id_user.c @@ -0,0 +1,187 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) 2018 Facebook + +#include +#include +#include + +#include +#include +#include +#include +#include + + +#include +#include + +#include "bpf_rlimit.h" +#include "cgroup_helpers.h" + +#define CGROUP_PATH "/skb_cgroup_test" +#define NUM_CGROUP_LEVELS 4 + +/* RFC 4291, Section 2.7.1 */ +#define LINKLOCAL_MULTICAST "ff02::1" + +static int mk_dst_addr(const char *ip, const char *iface, + struct sockaddr_in6 *dst) +{ + memset(dst, 0, sizeof(*dst)); + + dst->sin6_family = AF_INET6; + dst->sin6_port = htons(1025); + + if (inet_pton(AF_INET6, ip, &dst->sin6_addr) != 1) { + log_err("Invalid IPv6: %s", ip); + return -1; + } + + dst->sin6_scope_id = if_nametoindex(iface); + if (!dst->sin6_scope_id) { + log_err("Failed to get index of iface: %s", iface); + return -1; + } + + return 0; +} + +static int send_packet(const char *iface) +{ + struct sockaddr_in6 dst; + char msg[] = "msg"; + int err = 0; + int fd = -1; + + if (mk_dst_addr(LINKLOCAL_MULTICAST, iface, &dst)) + goto err; + + fd = socket(AF_INET6, SOCK_DGRAM, 0); + if (fd == -1) { + log_err("Failed to create UDP socket"); + goto err; + } + + if (sendto(fd, &msg, sizeof(msg), 0, (const struct sockaddr *)&dst, + sizeof(dst)) == -1) { + log_err("Failed to send datagram"); + goto err; + } + + goto out; +err: + err = -1; +out: + if (fd >= 0) + close(fd); + return err; +} + +int get_map_fd_by_prog_id(int prog_id) +{ + struct bpf_prog_info info = {}; + __u32 info_len = sizeof(info); + __u32 map_ids[1]; + int prog_fd = -1; + int map_fd = -1; + + prog_fd = bpf_prog_get_fd_by_id(prog_id); + if (prog_fd < 0) { + log_err("Failed to get fd by prog id %d", prog_id); + goto err; + } + + info.nr_map_ids = 1; + info.map_ids = (__u64) (unsigned long) map_ids; + + if (bpf_obj_get_info_by_fd(prog_fd, &info, &info_len)) { + log_err("Failed to get info by prog fd %d", prog_fd); + goto err; + } + + if (!info.nr_map_ids) { + log_err("No maps found for prog fd %d", prog_fd); + goto err; + } + + map_fd = bpf_map_get_fd_by_id(map_ids[0]); + if (map_fd < 0) + log_err("Failed to get fd by map id %d", map_ids[0]); +err: + if (prog_fd >= 0) + close(prog_fd); + return map_fd; +} + +int check_ancestor_cgroup_ids(int prog_id) +{ + __u64 actual_ids[NUM_CGROUP_LEVELS], expected_ids[NUM_CGROUP_LEVELS]; + __u32 level; + int err = 0; + int map_fd; + + expected_ids[0] = 0x100000001; /* root cgroup */ + expected_ids[1] = get_cgroup_id(""); + expected_ids[2] = get_cgroup_id(CGROUP_PATH); + expected_ids[3] = 0; /* non-existent cgroup */ + + map_fd = get_map_fd_by_prog_id(prog_id); + if (map_fd < 0) + goto err; + + for (level = 0; level < NUM_CGROUP_LEVELS; ++level) { + if (bpf_map_lookup_elem(map_fd, &level, &actual_ids[level])) { + log_err("Failed to lookup key %d", level); + goto err; + } + if (actual_ids[level] != expected_ids[level]) { + log_err("%llx (actual) != %llx (expected), level: %u\n", + actual_ids[level], expected_ids[level], level); + goto err; + } + } + + goto out; +err: + err = -1; +out: + if (map_fd >= 0) + close(map_fd); + return err; +} + +int main(int argc, char **argv) +{ + int cgfd = -1; + int err = 0; + + if (argc < 3) { + fprintf(stderr, "Usage: %s iface prog_id\n", argv[0]); + exit(EXIT_FAILURE); + } + + if (setup_cgroup_environment()) + goto err; + + cgfd = create_and_get_cgroup(CGROUP_PATH); + if (!cgfd) + goto err; + + if (join_cgroup(CGROUP_PATH)) + goto err; + + if (send_packet(argv[1])) + goto err; + + if (check_ancestor_cgroup_ids(atoi(argv[2]))) + goto err; + + goto out; +err: + err = -1; +out: + close(cgfd); + cleanup_cgroup_environment(); + printf("[%s]\n", err ? "FAIL" : "PASS"); + return err; +}