diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h index 0b41fd5fc96b74a738f03d828d3ce1fb36dbf5bc..272626cc3fc9dbd40aa828eeb236a150a2b9774c 100644 --- a/include/linux/bpf-cgroup.h +++ b/include/linux/bpf-cgroup.h @@ -57,8 +57,6 @@ struct bpf_cgroup_link { enum bpf_attach_type type; }; -extern const struct bpf_link_ops bpf_cgroup_link_lops; - struct bpf_prog_list { struct list_head node; struct bpf_prog *prog; @@ -100,8 +98,6 @@ int __cgroup_bpf_attach(struct cgroup *cgrp, int __cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog, struct bpf_cgroup_link *link, enum bpf_attach_type type); -int __cgroup_bpf_replace(struct cgroup *cgrp, struct bpf_cgroup_link *link, - struct bpf_prog *new_prog); int __cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr, union bpf_attr __user *uattr); @@ -112,8 +108,6 @@ int cgroup_bpf_attach(struct cgroup *cgrp, u32 flags); int cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog, enum bpf_attach_type type); -int cgroup_bpf_replace(struct bpf_link *link, struct bpf_prog *old_prog, - struct bpf_prog *new_prog); int cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr, union bpf_attr __user *uattr); @@ -353,7 +347,6 @@ int cgroup_bpf_prog_query(const union bpf_attr *attr, #else struct bpf_prog; -struct bpf_link; struct cgroup_bpf {}; static inline int cgroup_bpf_inherit(struct cgroup *cgrp) { return 0; } static inline void cgroup_bpf_offline(struct cgroup *cgrp) {} @@ -377,13 +370,6 @@ static inline int cgroup_bpf_link_attach(const union bpf_attr *attr, return -EINVAL; } -static inline int cgroup_bpf_replace(struct bpf_link *link, - struct bpf_prog *old_prog, - struct bpf_prog *new_prog) -{ - return -EINVAL; -} - static inline int cgroup_bpf_prog_query(const union bpf_attr *attr, union bpf_attr __user *uattr) { diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 10960cfabea40f497d086432a9d6912a253c38d9..c07b1d2f38245e0b72aa4a200584abb988103670 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -1026,9 +1026,11 @@ extern const struct file_operations bpf_prog_fops; extern const struct bpf_verifier_ops _name ## _verifier_ops; #define BPF_MAP_TYPE(_id, _ops) \ extern const struct bpf_map_ops _ops; +#define BPF_LINK_TYPE(_id, _name) #include #undef BPF_PROG_TYPE #undef BPF_MAP_TYPE +#undef BPF_LINK_TYPE extern const struct bpf_prog_ops bpf_offload_prog_ops; extern const struct bpf_verifier_ops tc_cls_act_analyzer_ops; @@ -1085,21 +1087,35 @@ int bpf_prog_new_fd(struct bpf_prog *prog); struct bpf_link { atomic64_t refcnt; + u32 id; + enum bpf_link_type type; const struct bpf_link_ops *ops; struct bpf_prog *prog; struct work_struct work; }; +struct bpf_link_primer { + struct bpf_link *link; + struct file *file; + int fd; + u32 id; +}; + struct bpf_link_ops { void (*release)(struct bpf_link *link); void (*dealloc)(struct bpf_link *link); - + int (*update_prog)(struct bpf_link *link, struct bpf_prog *new_prog, + struct bpf_prog *old_prog); + void (*show_fdinfo)(const struct bpf_link *link, struct seq_file *seq); + int (*fill_link_info)(const struct bpf_link *link, + struct bpf_link_info *info); }; -void bpf_link_init(struct bpf_link *link, const struct bpf_link_ops *ops, - struct bpf_prog *prog); -void bpf_link_cleanup(struct bpf_link *link, struct file *link_file, - int link_fd); +void bpf_link_init(struct bpf_link *link, enum bpf_link_type type, + const struct bpf_link_ops *ops, struct bpf_prog *prog); +int bpf_link_prime(struct bpf_link *link, struct bpf_link_primer *primer); +int bpf_link_settle(struct bpf_link_primer *primer); +void bpf_link_cleanup(struct bpf_link_primer *primer); void bpf_link_inc(struct bpf_link *link); void bpf_link_put(struct bpf_link *link); int bpf_link_new_fd(struct bpf_link *link); diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h index ba0c2d56f8a323ade0e95bfcfe6901ce77b3a05f..8345cdf553b8d78c29fa0cfdefcdc273099245ab 100644 --- a/include/linux/bpf_types.h +++ b/include/linux/bpf_types.h @@ -118,3 +118,9 @@ BPF_MAP_TYPE(BPF_MAP_TYPE_STACK, stack_map_ops) #if defined(CONFIG_BPF_JIT) BPF_MAP_TYPE(BPF_MAP_TYPE_STRUCT_OPS, bpf_struct_ops_map_ops) #endif + +BPF_LINK_TYPE(BPF_LINK_TYPE_RAW_TRACEPOINT, raw_tracepoint) +BPF_LINK_TYPE(BPF_LINK_TYPE_TRACING, tracing) +#ifdef CONFIG_CGROUP_BPF +BPF_LINK_TYPE(BPF_LINK_TYPE_CGROUP, cgroup) +#endif diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 4a6c47f3febea1dddcfda17c8e3ee868e424c5cc..0eccafae55bbc1b589a22e6308cbc4557d04f74a 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -113,6 +113,8 @@ enum bpf_cmd { BPF_MAP_DELETE_BATCH, BPF_LINK_CREATE, BPF_LINK_UPDATE, + BPF_LINK_GET_FD_BY_ID, + BPF_LINK_GET_NEXT_ID, }; enum bpf_map_type { @@ -220,6 +222,15 @@ enum bpf_attach_type { #define MAX_BPF_ATTACH_TYPE __MAX_BPF_ATTACH_TYPE +enum bpf_link_type { + BPF_LINK_TYPE_UNSPEC = 0, + BPF_LINK_TYPE_RAW_TRACEPOINT = 1, + BPF_LINK_TYPE_TRACING = 2, + BPF_LINK_TYPE_CGROUP = 3, + + MAX_BPF_LINK_TYPE, +}; + /* cgroup-bpf attach flags used in BPF_PROG_ATTACH command * * NONE(default): No further bpf programs allowed in the subtree. @@ -523,6 +534,7 @@ union bpf_attr { __u32 prog_id; __u32 map_id; __u32 btf_id; + __u32 link_id; }; __u32 next_id; __u32 open_flags; @@ -3609,6 +3621,25 @@ struct bpf_btf_info { __u32 id; } __attribute__((aligned(8))); +struct bpf_link_info { + __u32 type; + __u32 id; + __u32 prog_id; + union { + struct { + __aligned_u64 tp_name; /* in/out: tp_name buffer ptr */ + __u32 tp_name_len; /* in/out: tp_name buffer len */ + } raw_tracepoint; + struct { + __u32 attach_type; + } tracing; + struct { + __u64 cgroup_id; + __u32 attach_type; + } cgroup; + }; +} __attribute__((aligned(8))); + /* User bpf_sock_addr struct to access socket fields and sockaddr struct passed * by user and intended to be used by socket (e.g. to bind to, depends on * attach attach type). diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index d65c6912bdaf66d6d1f0bde1ea759fde2928e2d4..a2cfba89a8e1d780b93d9a6c723b7363059e8486 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -3482,6 +3482,7 @@ extern char __weak __stop_BTF[]; extern struct btf *btf_vmlinux; #define BPF_MAP_TYPE(_id, _ops) +#define BPF_LINK_TYPE(_id, _name) static union { struct bpf_ctx_convert { #define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \ @@ -3508,6 +3509,7 @@ static u8 bpf_ctx_convert_map[] = { 0, /* avoid empty array */ }; #undef BPF_MAP_TYPE +#undef BPF_LINK_TYPE static const struct btf_member * btf_get_prog_ctx_type(struct bpf_verifier_log *log, struct btf *btf, diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c index bf634959885ca4faa40b685a99fd1d93963abc69..5c0e964105ac9070d284d160da7b43305ec8afda 100644 --- a/kernel/bpf/cgroup.c +++ b/kernel/bpf/cgroup.c @@ -557,8 +557,9 @@ static void replace_effective_prog(struct cgroup *cgrp, * * Must be called with cgroup_mutex held. */ -int __cgroup_bpf_replace(struct cgroup *cgrp, struct bpf_cgroup_link *link, - struct bpf_prog *new_prog) +static int __cgroup_bpf_replace(struct cgroup *cgrp, + struct bpf_cgroup_link *link, + struct bpf_prog *new_prog) { struct list_head *progs = &cgrp->bpf.progs[link->type]; struct bpf_prog *old_prog; @@ -583,6 +584,30 @@ int __cgroup_bpf_replace(struct cgroup *cgrp, struct bpf_cgroup_link *link, return 0; } +static int cgroup_bpf_replace(struct bpf_link *link, struct bpf_prog *new_prog, + struct bpf_prog *old_prog) +{ + struct bpf_cgroup_link *cg_link; + int ret; + + cg_link = container_of(link, struct bpf_cgroup_link, link); + + mutex_lock(&cgroup_mutex); + /* link might have been auto-released by dying cgroup, so fail */ + if (!cg_link->cgroup) { + ret = -EINVAL; + goto out_unlock; + } + if (old_prog && link->prog != old_prog) { + ret = -EPERM; + goto out_unlock; + } + ret = __cgroup_bpf_replace(cg_link->cgroup, cg_link, new_prog); +out_unlock: + mutex_unlock(&cgroup_mutex); + return ret; +} + static struct bpf_prog_list *find_detach_entry(struct list_head *progs, struct bpf_prog *prog, struct bpf_cgroup_link *link, @@ -808,17 +833,56 @@ static void bpf_cgroup_link_dealloc(struct bpf_link *link) kfree(cg_link); } -const struct bpf_link_ops bpf_cgroup_link_lops = { +static void bpf_cgroup_link_show_fdinfo(const struct bpf_link *link, + struct seq_file *seq) +{ + struct bpf_cgroup_link *cg_link = + container_of(link, struct bpf_cgroup_link, link); + u64 cg_id = 0; + + mutex_lock(&cgroup_mutex); + if (cg_link->cgroup) + cg_id = cgroup_id(cg_link->cgroup); + mutex_unlock(&cgroup_mutex); + + seq_printf(seq, + "cgroup_id:\t%llu\n" + "attach_type:\t%d\n", + cg_id, + cg_link->type); +} + +static int bpf_cgroup_link_fill_link_info(const struct bpf_link *link, + struct bpf_link_info *info) +{ + struct bpf_cgroup_link *cg_link = + container_of(link, struct bpf_cgroup_link, link); + u64 cg_id = 0; + + mutex_lock(&cgroup_mutex); + if (cg_link->cgroup) + cg_id = cgroup_id(cg_link->cgroup); + mutex_unlock(&cgroup_mutex); + + info->cgroup.cgroup_id = cg_id; + info->cgroup.attach_type = cg_link->type; + return 0; +} + +static const struct bpf_link_ops bpf_cgroup_link_lops = { .release = bpf_cgroup_link_release, .dealloc = bpf_cgroup_link_dealloc, + .update_prog = cgroup_bpf_replace, + .show_fdinfo = bpf_cgroup_link_show_fdinfo, + .fill_link_info = bpf_cgroup_link_fill_link_info, }; int cgroup_bpf_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) { + struct bpf_link_primer link_primer; struct bpf_cgroup_link *link; - struct file *link_file; struct cgroup *cgrp; - int err, link_fd; + int err; if (attr->link_create.flags) return -EINVAL; @@ -832,26 +896,25 @@ int cgroup_bpf_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) err = -ENOMEM; goto out_put_cgroup; } - bpf_link_init(&link->link, &bpf_cgroup_link_lops, prog); + bpf_link_init(&link->link, BPF_LINK_TYPE_CGROUP, &bpf_cgroup_link_lops, + prog); link->cgroup = cgrp; link->type = attr->link_create.attach_type; - link_file = bpf_link_new_file(&link->link, &link_fd); - if (IS_ERR(link_file)) { + err = bpf_link_prime(&link->link, &link_primer); + if (err) { kfree(link); - err = PTR_ERR(link_file); goto out_put_cgroup; } err = cgroup_bpf_attach(cgrp, NULL, NULL, link, link->type, BPF_F_ALLOW_MULTI); if (err) { - bpf_link_cleanup(&link->link, link_file, link_fd); + bpf_link_cleanup(&link_primer); goto out_put_cgroup; } - fd_install(link_fd, link_file); - return link_fd; + return bpf_link_settle(&link_primer); out_put_cgroup: cgroup_put(cgrp); diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 7626b802447128f4fc5ec789e24d9bb6d8e96a27..d23c04cbe14f7e488f2b9d6ca881da67215ab336 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -42,6 +42,8 @@ static DEFINE_IDR(prog_idr); static DEFINE_SPINLOCK(prog_idr_lock); static DEFINE_IDR(map_idr); static DEFINE_SPINLOCK(map_idr_lock); +static DEFINE_IDR(link_idr); +static DEFINE_SPINLOCK(link_idr_lock); int sysctl_unprivileged_bpf_disabled __read_mostly; @@ -49,9 +51,11 @@ static const struct bpf_map_ops * const bpf_map_types[] = { #define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) #define BPF_MAP_TYPE(_id, _ops) \ [_id] = &_ops, +#define BPF_LINK_TYPE(_id, _name) #include #undef BPF_PROG_TYPE #undef BPF_MAP_TYPE +#undef BPF_LINK_TYPE }; /* @@ -1546,9 +1550,11 @@ static const struct bpf_prog_ops * const bpf_prog_types[] = { #define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \ [_id] = & _name ## _prog_ops, #define BPF_MAP_TYPE(_id, _ops) +#define BPF_LINK_TYPE(_id, _name) #include #undef BPF_PROG_TYPE #undef BPF_MAP_TYPE +#undef BPF_LINK_TYPE }; static int find_prog_type(enum bpf_prog_type type, struct bpf_prog *prog) @@ -2181,25 +2187,39 @@ static int bpf_obj_get(const union bpf_attr *attr) attr->file_flags); } -void bpf_link_init(struct bpf_link *link, const struct bpf_link_ops *ops, - struct bpf_prog *prog) +void bpf_link_init(struct bpf_link *link, enum bpf_link_type type, + const struct bpf_link_ops *ops, struct bpf_prog *prog) { atomic64_set(&link->refcnt, 1); + link->type = type; + link->id = 0; link->ops = ops; link->prog = prog; } +static void bpf_link_free_id(int id) +{ + if (!id) + return; + + spin_lock_bh(&link_idr_lock); + idr_remove(&link_idr, id); + spin_unlock_bh(&link_idr_lock); +} + /* Clean up bpf_link and corresponding anon_inode file and FD. After * anon_inode is created, bpf_link can't be just kfree()'d due to deferred - * anon_inode's release() call. This helper manages marking bpf_link as - * defunct, releases anon_inode file and puts reserved FD. + * anon_inode's release() call. This helper marksbpf_link as + * defunct, releases anon_inode file and puts reserved FD. bpf_prog's refcnt + * is not decremented, it's the responsibility of a calling code that failed + * to complete bpf_link initialization. */ -void bpf_link_cleanup(struct bpf_link *link, struct file *link_file, - int link_fd) +void bpf_link_cleanup(struct bpf_link_primer *primer) { - link->prog = NULL; - fput(link_file); - put_unused_fd(link_fd); + primer->link->prog = NULL; + bpf_link_free_id(primer->id); + fput(primer->file); + put_unused_fd(primer->fd); } void bpf_link_inc(struct bpf_link *link) @@ -2210,6 +2230,7 @@ void bpf_link_inc(struct bpf_link *link) /* bpf_link_free is guaranteed to be called from process context */ static void bpf_link_free(struct bpf_link *link) { + bpf_link_free_id(link->id); if (link->prog) { /* detach BPF program, clean up used resources */ link->ops->release(link); @@ -2250,36 +2271,36 @@ static int bpf_link_release(struct inode *inode, struct file *filp) return 0; } -#ifdef CONFIG_PROC_FS -static const struct bpf_link_ops bpf_raw_tp_lops; -static const struct bpf_link_ops bpf_tracing_link_lops; +#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) +#define BPF_MAP_TYPE(_id, _ops) +#define BPF_LINK_TYPE(_id, _name) [_id] = #_name, +static const char *bpf_link_type_strs[] = { + [BPF_LINK_TYPE_UNSPEC] = "", +#include +}; +#undef BPF_PROG_TYPE +#undef BPF_MAP_TYPE +#undef BPF_LINK_TYPE +#ifdef CONFIG_PROC_FS static void bpf_link_show_fdinfo(struct seq_file *m, struct file *filp) { const struct bpf_link *link = filp->private_data; const struct bpf_prog *prog = link->prog; char prog_tag[sizeof(prog->tag) * 2 + 1] = { }; - const char *link_type; - - if (link->ops == &bpf_raw_tp_lops) - link_type = "raw_tracepoint"; - else if (link->ops == &bpf_tracing_link_lops) - link_type = "tracing"; -#ifdef CONFIG_CGROUP_BPF - else if (link->ops == &bpf_cgroup_link_lops) - link_type = "cgroup"; -#endif - else - link_type = "unknown"; bin2hex(prog_tag, prog->tag, sizeof(prog->tag)); seq_printf(m, "link_type:\t%s\n" + "link_id:\t%u\n" "prog_tag:\t%s\n" "prog_id:\t%u\n", - link_type, + bpf_link_type_strs[link->type], + link->id, prog_tag, prog->aux->id); + if (link->ops->show_fdinfo) + link->ops->show_fdinfo(link, m); } #endif @@ -2292,36 +2313,76 @@ static const struct file_operations bpf_link_fops = { .write = bpf_dummy_write, }; -int bpf_link_new_fd(struct bpf_link *link) +static int bpf_link_alloc_id(struct bpf_link *link) { - return anon_inode_getfd("bpf-link", &bpf_link_fops, link, O_CLOEXEC); -} + int id; + + idr_preload(GFP_KERNEL); + spin_lock_bh(&link_idr_lock); + id = idr_alloc_cyclic(&link_idr, link, 1, INT_MAX, GFP_ATOMIC); + spin_unlock_bh(&link_idr_lock); + idr_preload_end(); -/* Similar to bpf_link_new_fd, create anon_inode for given bpf_link, but - * instead of immediately installing fd in fdtable, just reserve it and - * return. Caller then need to either install it with fd_install(fd, file) or - * release with put_unused_fd(fd). - * This is useful for cases when bpf_link attachment/detachment are - * complicated and expensive operations and should be delayed until all the fd - * reservation and anon_inode creation succeeds. + return id; +} + +/* Prepare bpf_link to be exposed to user-space by allocating anon_inode file, + * reserving unused FD and allocating ID from link_idr. This is to be paired + * with bpf_link_settle() to install FD and ID and expose bpf_link to + * user-space, if bpf_link is successfully attached. If not, bpf_link and + * pre-allocated resources are to be freed with bpf_cleanup() call. All the + * transient state is passed around in struct bpf_link_primer. + * This is preferred way to create and initialize bpf_link, especially when + * there are complicated and expensive operations inbetween creating bpf_link + * itself and attaching it to BPF hook. By using bpf_link_prime() and + * bpf_link_settle() kernel code using bpf_link doesn't have to perform + * expensive (and potentially failing) roll back operations in a rare case + * that file, FD, or ID can't be allocated. */ -struct file *bpf_link_new_file(struct bpf_link *link, int *reserved_fd) +int bpf_link_prime(struct bpf_link *link, struct bpf_link_primer *primer) { struct file *file; - int fd; + int fd, id; fd = get_unused_fd_flags(O_CLOEXEC); if (fd < 0) - return ERR_PTR(fd); + return fd; file = anon_inode_getfile("bpf_link", &bpf_link_fops, link, O_CLOEXEC); if (IS_ERR(file)) { put_unused_fd(fd); - return file; + return PTR_ERR(file); + } + + id = bpf_link_alloc_id(link); + if (id < 0) { + put_unused_fd(fd); + fput(file); + return id; } - *reserved_fd = fd; - return file; + primer->link = link; + primer->file = file; + primer->fd = fd; + primer->id = id; + return 0; +} + +int bpf_link_settle(struct bpf_link_primer *primer) +{ + /* make bpf_link fetchable by ID */ + spin_lock_bh(&link_idr_lock); + primer->link->id = primer->id; + spin_unlock_bh(&link_idr_lock); + /* make bpf_link fetchable by FD */ + fd_install(primer->fd, primer->file); + /* pass through installed FD */ + return primer->fd; +} + +int bpf_link_new_fd(struct bpf_link *link) +{ + return anon_inode_getfd("bpf-link", &bpf_link_fops, link, O_CLOEXEC); } struct bpf_link *bpf_link_get_from_fd(u32 ufd) @@ -2345,6 +2406,7 @@ struct bpf_link *bpf_link_get_from_fd(u32 ufd) struct bpf_tracing_link { struct bpf_link link; + enum bpf_attach_type attach_type; }; static void bpf_tracing_link_release(struct bpf_link *link) @@ -2360,16 +2422,40 @@ static void bpf_tracing_link_dealloc(struct bpf_link *link) kfree(tr_link); } +static void bpf_tracing_link_show_fdinfo(const struct bpf_link *link, + struct seq_file *seq) +{ + struct bpf_tracing_link *tr_link = + container_of(link, struct bpf_tracing_link, link); + + seq_printf(seq, + "attach_type:\t%d\n", + tr_link->attach_type); +} + +static int bpf_tracing_link_fill_link_info(const struct bpf_link *link, + struct bpf_link_info *info) +{ + struct bpf_tracing_link *tr_link = + container_of(link, struct bpf_tracing_link, link); + + info->tracing.attach_type = tr_link->attach_type; + + return 0; +} + static const struct bpf_link_ops bpf_tracing_link_lops = { .release = bpf_tracing_link_release, .dealloc = bpf_tracing_link_dealloc, + .show_fdinfo = bpf_tracing_link_show_fdinfo, + .fill_link_info = bpf_tracing_link_fill_link_info, }; static int bpf_tracing_prog_attach(struct bpf_prog *prog) { + struct bpf_link_primer link_primer; struct bpf_tracing_link *link; - struct file *link_file; - int link_fd, err; + int err; switch (prog->type) { case BPF_PROG_TYPE_TRACING: @@ -2402,24 +2488,23 @@ static int bpf_tracing_prog_attach(struct bpf_prog *prog) err = -ENOMEM; goto out_put_prog; } - bpf_link_init(&link->link, &bpf_tracing_link_lops, prog); + bpf_link_init(&link->link, BPF_LINK_TYPE_TRACING, + &bpf_tracing_link_lops, prog); + link->attach_type = prog->expected_attach_type; - link_file = bpf_link_new_file(&link->link, &link_fd); - if (IS_ERR(link_file)) { + err = bpf_link_prime(&link->link, &link_primer); + if (err) { kfree(link); - err = PTR_ERR(link_file); goto out_put_prog; } err = bpf_trampoline_link_prog(prog); if (err) { - bpf_link_cleanup(&link->link, link_file, link_fd); + bpf_link_cleanup(&link_primer); goto out_put_prog; } - fd_install(link_fd, link_file); - return link_fd; - + return bpf_link_settle(&link_primer); out_put_prog: bpf_prog_put(prog); return err; @@ -2447,22 +2532,69 @@ static void bpf_raw_tp_link_dealloc(struct bpf_link *link) kfree(raw_tp); } -static const struct bpf_link_ops bpf_raw_tp_lops = { +static void bpf_raw_tp_link_show_fdinfo(const struct bpf_link *link, + struct seq_file *seq) +{ + struct bpf_raw_tp_link *raw_tp_link = + container_of(link, struct bpf_raw_tp_link, link); + + seq_printf(seq, + "tp_name:\t%s\n", + raw_tp_link->btp->tp->name); +} + +static int bpf_raw_tp_link_fill_link_info(const struct bpf_link *link, + struct bpf_link_info *info) +{ + struct bpf_raw_tp_link *raw_tp_link = + container_of(link, struct bpf_raw_tp_link, link); + char __user *ubuf = u64_to_user_ptr(info->raw_tracepoint.tp_name); + const char *tp_name = raw_tp_link->btp->tp->name; + u32 ulen = info->raw_tracepoint.tp_name_len; + size_t tp_len = strlen(tp_name); + + if (ulen && !ubuf) + return -EINVAL; + + info->raw_tracepoint.tp_name_len = tp_len + 1; + + if (!ubuf) + return 0; + + if (ulen >= tp_len + 1) { + if (copy_to_user(ubuf, tp_name, tp_len + 1)) + return -EFAULT; + } else { + char zero = '\0'; + + if (copy_to_user(ubuf, tp_name, ulen - 1)) + return -EFAULT; + if (put_user(zero, ubuf + ulen - 1)) + return -EFAULT; + return -ENOSPC; + } + + return 0; +} + +static const struct bpf_link_ops bpf_raw_tp_link_lops = { .release = bpf_raw_tp_link_release, .dealloc = bpf_raw_tp_link_dealloc, + .show_fdinfo = bpf_raw_tp_link_show_fdinfo, + .fill_link_info = bpf_raw_tp_link_fill_link_info, }; #define BPF_RAW_TRACEPOINT_OPEN_LAST_FIELD raw_tracepoint.prog_fd static int bpf_raw_tracepoint_open(const union bpf_attr *attr) { + struct bpf_link_primer link_primer; struct bpf_raw_tp_link *link; struct bpf_raw_event_map *btp; - struct file *link_file; struct bpf_prog *prog; const char *tp_name; char buf[128]; - int link_fd, err; + int err; if (CHECK_ATTR(BPF_RAW_TRACEPOINT_OPEN)) return -EINVAL; @@ -2515,24 +2647,23 @@ static int bpf_raw_tracepoint_open(const union bpf_attr *attr) err = -ENOMEM; goto out_put_btp; } - bpf_link_init(&link->link, &bpf_raw_tp_lops, prog); + bpf_link_init(&link->link, BPF_LINK_TYPE_RAW_TRACEPOINT, + &bpf_raw_tp_link_lops, prog); link->btp = btp; - link_file = bpf_link_new_file(&link->link, &link_fd); - if (IS_ERR(link_file)) { + err = bpf_link_prime(&link->link, &link_primer); + if (err) { kfree(link); - err = PTR_ERR(link_file); goto out_put_btp; } err = bpf_probe_register(link->btp, prog); if (err) { - bpf_link_cleanup(&link->link, link_file, link_fd); + bpf_link_cleanup(&link_primer); goto out_put_btp; } - fd_install(link_fd, link_file); - return link_fd; + return bpf_link_settle(&link_primer); out_put_btp: bpf_put_raw_tracepoint(btp); @@ -3313,6 +3444,42 @@ static int bpf_btf_get_info_by_fd(struct btf *btf, return btf_get_info_by_fd(btf, attr, uattr); } +static int bpf_link_get_info_by_fd(struct bpf_link *link, + const union bpf_attr *attr, + union bpf_attr __user *uattr) +{ + struct bpf_link_info __user *uinfo = u64_to_user_ptr(attr->info.info); + struct bpf_link_info info; + u32 info_len = attr->info.info_len; + int err; + + err = bpf_check_uarg_tail_zero(uinfo, sizeof(info), info_len); + if (err) + return err; + info_len = min_t(u32, sizeof(info), info_len); + + memset(&info, 0, sizeof(info)); + if (copy_from_user(&info, uinfo, info_len)) + return -EFAULT; + + info.type = link->type; + info.id = link->id; + info.prog_id = link->prog->aux->id; + + if (link->ops->fill_link_info) { + err = link->ops->fill_link_info(link, &info); + if (err) + return err; + } + + if (copy_to_user(uinfo, &info, info_len) || + put_user(info_len, &uattr->info.info_len)) + return -EFAULT; + + return 0; +} + + #define BPF_OBJ_GET_INFO_BY_FD_LAST_FIELD info.info static int bpf_obj_get_info_by_fd(const union bpf_attr *attr, @@ -3337,6 +3504,9 @@ static int bpf_obj_get_info_by_fd(const union bpf_attr *attr, uattr); else if (f.file->f_op == &btf_fops) err = bpf_btf_get_info_by_fd(f.file->private_data, attr, uattr); + else if (f.file->f_op == &bpf_link_fops) + err = bpf_link_get_info_by_fd(f.file->private_data, + attr, uattr); else err = -EINVAL; @@ -3464,7 +3634,7 @@ static int bpf_task_fd_query(const union bpf_attr *attr, if (file->f_op == &bpf_link_fops) { struct bpf_link *link = file->private_data; - if (link->ops == &bpf_raw_tp_lops) { + if (link->ops == &bpf_raw_tp_link_lops) { struct bpf_raw_tp_link *raw_tp = container_of(link, struct bpf_raw_tp_link, link); struct bpf_raw_event_map *btp = raw_tp->btp; @@ -3645,13 +3815,10 @@ static int link_update(union bpf_attr *attr) goto out_put_progs; } -#ifdef CONFIG_CGROUP_BPF - if (link->ops == &bpf_cgroup_link_lops) { - ret = cgroup_bpf_replace(link, old_prog, new_prog); - goto out_put_progs; - } -#endif - ret = -EINVAL; + if (link->ops->update_prog) + ret = link->ops->update_prog(link, new_prog, old_prog); + else + ret = EINVAL; out_put_progs: if (old_prog) @@ -3663,6 +3830,48 @@ static int link_update(union bpf_attr *attr) return ret; } +static int bpf_link_inc_not_zero(struct bpf_link *link) +{ + return atomic64_fetch_add_unless(&link->refcnt, 1, 0) ? 0 : -ENOENT; +} + +#define BPF_LINK_GET_FD_BY_ID_LAST_FIELD link_id + +static int bpf_link_get_fd_by_id(const union bpf_attr *attr) +{ + struct bpf_link *link; + u32 id = attr->link_id; + int fd, err; + + if (CHECK_ATTR(BPF_LINK_GET_FD_BY_ID)) + return -EINVAL; + + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + spin_lock_bh(&link_idr_lock); + link = idr_find(&link_idr, id); + /* before link is "settled", ID is 0, pretend it doesn't exist yet */ + if (link) { + if (link->id) + err = bpf_link_inc_not_zero(link); + else + err = -EAGAIN; + } else { + err = -ENOENT; + } + spin_unlock_bh(&link_idr_lock); + + if (err) + return err; + + fd = bpf_link_new_fd(link); + if (fd < 0) + bpf_link_put(link); + + return fd; +} + SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, size) { union bpf_attr attr; @@ -3780,6 +3989,13 @@ SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, siz case BPF_LINK_UPDATE: err = link_update(&attr); break; + case BPF_LINK_GET_FD_BY_ID: + err = bpf_link_get_fd_by_id(&attr); + break; + case BPF_LINK_GET_NEXT_ID: + err = bpf_obj_get_next_id(&attr, uattr, + &link_idr, &link_idr_lock); + break; default: err = -EINVAL; break; diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 91728e0f27ebab39dceb080a9869a66499253e84..2b337e32aa9482a2be6b130efac582b53137953f 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -28,9 +28,11 @@ static const struct bpf_verifier_ops * const bpf_verifier_ops[] = { #define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \ [_id] = & _name ## _verifier_ops, #define BPF_MAP_TYPE(_id, _ops) +#define BPF_LINK_TYPE(_id, _name) #include #undef BPF_PROG_TYPE #undef BPF_MAP_TYPE +#undef BPF_LINK_TYPE }; /* bpf_check() is a static code analyzer that walks eBPF program diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 06b5ea9d899d81d020fbd51ce8d6fdf1a75e169f..557a9b9d22446d9849c75831268b89c660ee978b 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -6508,33 +6508,6 @@ int cgroup_bpf_attach(struct cgroup *cgrp, return ret; } -int cgroup_bpf_replace(struct bpf_link *link, struct bpf_prog *old_prog, - struct bpf_prog *new_prog) -{ - struct bpf_cgroup_link *cg_link; - int ret; - - if (link->ops != &bpf_cgroup_link_lops) - return -EINVAL; - - cg_link = container_of(link, struct bpf_cgroup_link, link); - - mutex_lock(&cgroup_mutex); - /* link might have been auto-released by dying cgroup, so fail */ - if (!cg_link->cgroup) { - ret = -EINVAL; - goto out_unlock; - } - if (old_prog && link->prog != old_prog) { - ret = -EPERM; - goto out_unlock; - } - ret = __cgroup_bpf_replace(cg_link->cgroup, cg_link, new_prog); -out_unlock: - mutex_unlock(&cgroup_mutex); - return ret; -} - int cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog, enum bpf_attach_type type) { diff --git a/tools/bpf/bpftool/Documentation/bpftool-link.rst b/tools/bpf/bpftool/Documentation/bpftool-link.rst new file mode 100644 index 0000000000000000000000000000000000000000..ee6500d6e6e4064adbfd7679f0c7e7727f3c6dab --- /dev/null +++ b/tools/bpf/bpftool/Documentation/bpftool-link.rst @@ -0,0 +1,118 @@ +================ +bpftool-link +================ +------------------------------------------------------------------------------- +tool for inspection and simple manipulation of eBPF links +------------------------------------------------------------------------------- + +:Manual section: 8 + +SYNOPSIS +======== + + **bpftool** [*OPTIONS*] **link** *COMMAND* + + *OPTIONS* := { { **-j** | **--json** } [{ **-p** | **--pretty** }] | { **-f** | **--bpffs** } } + + *COMMANDS* := { **show** | **list** | **pin** | **help** } + +LINK COMMANDS +============= + +| **bpftool** **link { show | list }** [*LINK*] +| **bpftool** **link pin** *LINK* *FILE* +| **bpftool** **link help** +| +| *LINK* := { **id** *LINK_ID* | **pinned** *FILE* } + + +DESCRIPTION +=========== + **bpftool link { show | list }** [*LINK*] + Show information about active links. If *LINK* is + specified show information only about given link, + otherwise list all links currently active on the system. + + Output will start with link ID followed by link type and + zero or more named attributes, some of which depend on type + of link. + + **bpftool link pin** *LINK* *FILE* + Pin link *LINK* as *FILE*. + + Note: *FILE* must be located in *bpffs* mount. It must not + contain a dot character ('.'), which is reserved for future + extensions of *bpffs*. + + **bpftool link help** + Print short help message. + +OPTIONS +======= + -h, --help + Print short generic help message (similar to **bpftool help**). + + -V, --version + Print version number (similar to **bpftool version**). + + -j, --json + Generate JSON output. For commands that cannot produce JSON, this + option has no effect. + + -p, --pretty + Generate human-readable JSON output. Implies **-j**. + + -f, --bpffs + When showing BPF links, show file names of pinned + links. + + -n, --nomount + Do not automatically attempt to mount any virtual file system + (such as tracefs or BPF virtual file system) when necessary. + + -d, --debug + Print all logs available, even debug-level information. This + includes logs from libbpf. + +EXAMPLES +======== +**# bpftool link show** + +:: + + 10: cgroup prog 25 + cgroup_id 614 attach_type egress + +**# bpftool --json --pretty link show** + +:: + + [{ + "type": "cgroup", + "prog_id": 25, + "cgroup_id": 614, + "attach_type": "egress" + } + ] + +| +| **# bpftool link pin id 10 /sys/fs/bpf/link** +| **# ls -l /sys/fs/bpf/** + +:: + + -rw------- 1 root root 0 Apr 23 21:39 link + + +SEE ALSO +======== + **bpf**\ (2), + **bpf-helpers**\ (7), + **bpftool**\ (8), + **bpftool-prog\ (8), + **bpftool-map**\ (8), + **bpftool-cgroup**\ (8), + **bpftool-feature**\ (8), + **bpftool-net**\ (8), + **bpftool-perf**\ (8), + **bpftool-btf**\ (8) diff --git a/tools/bpf/bpftool/bash-completion/bpftool b/tools/bpf/bpftool/bash-completion/bpftool index 45ee99b159e222e38a01efd97110ce181cf337f0..c033c3329f7364c82fb008321c72e5aeead7d028 100644 --- a/tools/bpf/bpftool/bash-completion/bpftool +++ b/tools/bpf/bpftool/bash-completion/bpftool @@ -98,6 +98,12 @@ _bpftool_get_btf_ids() command sed -n 's/.*"id": \(.*\),$/\1/p' )" -- "$cur" ) ) } +_bpftool_get_link_ids() +{ + COMPREPLY+=( $( compgen -W "$( bpftool -jp link 2>&1 | \ + command sed -n 's/.*"id": \(.*\),$/\1/p' )" -- "$cur" ) ) +} + _bpftool_get_obj_map_names() { local obj @@ -1082,6 +1088,39 @@ _bpftool() ;; esac ;; + link) + case $command in + show|list|pin) + case $prev in + id) + _bpftool_get_link_ids + return 0 + ;; + esac + ;; + esac + + local LINK_TYPE='id pinned' + case $command in + show|list) + [[ $prev != "$command" ]] && return 0 + COMPREPLY=( $( compgen -W "$LINK_TYPE" -- "$cur" ) ) + return 0 + ;; + pin) + if [[ $prev == "$command" ]]; then + COMPREPLY=( $( compgen -W "$LINK_TYPE" -- "$cur" ) ) + else + _filedir + fi + return 0 + ;; + *) + [[ $prev == $object ]] && \ + COMPREPLY=( $( compgen -W 'help pin show list' -- "$cur" ) ) + ;; + esac + ;; esac } && complete -F _bpftool bpftool diff --git a/tools/bpf/bpftool/cgroup.c b/tools/bpf/bpftool/cgroup.c index 62c6a1d7cd18b66261f17d9d8b14571f85bcd8e1..1693c802bb20705be434a8fc3ab073e654511c6e 100644 --- a/tools/bpf/bpftool/cgroup.c +++ b/tools/bpf/bpftool/cgroup.c @@ -31,42 +31,20 @@ static unsigned int query_flags; -static const char * const attach_type_strings[] = { - [BPF_CGROUP_INET_INGRESS] = "ingress", - [BPF_CGROUP_INET_EGRESS] = "egress", - [BPF_CGROUP_INET_SOCK_CREATE] = "sock_create", - [BPF_CGROUP_SOCK_OPS] = "sock_ops", - [BPF_CGROUP_DEVICE] = "device", - [BPF_CGROUP_INET4_BIND] = "bind4", - [BPF_CGROUP_INET6_BIND] = "bind6", - [BPF_CGROUP_INET4_CONNECT] = "connect4", - [BPF_CGROUP_INET6_CONNECT] = "connect6", - [BPF_CGROUP_INET4_POST_BIND] = "post_bind4", - [BPF_CGROUP_INET6_POST_BIND] = "post_bind6", - [BPF_CGROUP_UDP4_SENDMSG] = "sendmsg4", - [BPF_CGROUP_UDP6_SENDMSG] = "sendmsg6", - [BPF_CGROUP_SYSCTL] = "sysctl", - [BPF_CGROUP_UDP4_RECVMSG] = "recvmsg4", - [BPF_CGROUP_UDP6_RECVMSG] = "recvmsg6", - [BPF_CGROUP_GETSOCKOPT] = "getsockopt", - [BPF_CGROUP_SETSOCKOPT] = "setsockopt", - [__MAX_BPF_ATTACH_TYPE] = NULL, -}; - static enum bpf_attach_type parse_attach_type(const char *str) { enum bpf_attach_type type; for (type = 0; type < __MAX_BPF_ATTACH_TYPE; type++) { - if (attach_type_strings[type] && - is_prefix(str, attach_type_strings[type])) + if (attach_type_name[type] && + is_prefix(str, attach_type_name[type])) return type; } return __MAX_BPF_ATTACH_TYPE; } -static int show_bpf_prog(int id, const char *attach_type_str, +static int show_bpf_prog(int id, enum bpf_attach_type attach_type, const char *attach_flags_str, int level) { @@ -86,18 +64,22 @@ static int show_bpf_prog(int id, const char *attach_type_str, if (json_output) { jsonw_start_object(json_wtr); jsonw_uint_field(json_wtr, "id", info.id); - jsonw_string_field(json_wtr, "attach_type", - attach_type_str); + if (attach_type < ARRAY_SIZE(attach_type_name)) + jsonw_string_field(json_wtr, "attach_type", + attach_type_name[attach_type]); + else + jsonw_uint_field(json_wtr, "attach_type", attach_type); jsonw_string_field(json_wtr, "attach_flags", attach_flags_str); jsonw_string_field(json_wtr, "name", info.name); jsonw_end_object(json_wtr); } else { - printf("%s%-8u %-15s %-15s %-15s\n", level ? " " : "", - info.id, - attach_type_str, - attach_flags_str, - info.name); + printf("%s%-8u ", level ? " " : "", info.id); + if (attach_type < ARRAY_SIZE(attach_type_name)) + printf("%-15s", attach_type_name[attach_type]); + else + printf("type %-10u", attach_type); + printf(" %-15s %-15s\n", attach_flags_str, info.name); } close(prog_fd); @@ -171,7 +153,7 @@ static int show_attached_bpf_progs(int cgroup_fd, enum bpf_attach_type type, } for (iter = 0; iter < prog_cnt; iter++) - show_bpf_prog(prog_ids[iter], attach_type_strings[type], + show_bpf_prog(prog_ids[iter], type, attach_flags_str, level); return 0; diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c index f2223dbdfb0af2bba35eb95f2072a39fabb4f73c..c47bdc65de8e267333ef6dcfc6fc29b602914d50 100644 --- a/tools/bpf/bpftool/common.c +++ b/tools/bpf/bpftool/common.c @@ -262,6 +262,8 @@ int get_fd_type(int fd) return BPF_OBJ_MAP; else if (strstr(buf, "bpf-prog")) return BPF_OBJ_PROG; + else if (strstr(buf, "bpf-link")) + return BPF_OBJ_LINK; return BPF_OBJ_UNKNOWN; } diff --git a/tools/bpf/bpftool/link.c b/tools/bpf/bpftool/link.c new file mode 100644 index 0000000000000000000000000000000000000000..adc7dc431ed8a634384bff66e78983bc31d02eec --- /dev/null +++ b/tools/bpf/bpftool/link.c @@ -0,0 +1,333 @@ +// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +/* Copyright (C) 2020 Facebook */ + +#include +#include +#include +#include + +#include + +#include "json_writer.h" +#include "main.h" + +static const char * const link_type_name[] = { + [BPF_LINK_TYPE_UNSPEC] = "unspec", + [BPF_LINK_TYPE_RAW_TRACEPOINT] = "raw_tracepoint", + [BPF_LINK_TYPE_TRACING] = "tracing", + [BPF_LINK_TYPE_CGROUP] = "cgroup", +}; + +static int link_parse_fd(int *argc, char ***argv) +{ + if (is_prefix(**argv, "id")) { + unsigned int id; + char *endptr; + + NEXT_ARGP(); + + id = strtoul(**argv, &endptr, 0); + if (*endptr) { + p_err("can't parse %s as ID", **argv); + return -1; + } + NEXT_ARGP(); + + return bpf_link_get_fd_by_id(id); + } else if (is_prefix(**argv, "pinned")) { + char *path; + + NEXT_ARGP(); + + path = **argv; + NEXT_ARGP(); + + return open_obj_pinned_any(path, BPF_OBJ_LINK); + } + + p_err("expected 'id' or 'pinned', got: '%s'?", **argv); + return -1; +} + +static void +show_link_header_json(struct bpf_link_info *info, json_writer_t *wtr) +{ + jsonw_uint_field(wtr, "id", info->id); + if (info->type < ARRAY_SIZE(link_type_name)) + jsonw_string_field(wtr, "type", link_type_name[info->type]); + else + jsonw_uint_field(wtr, "type", info->type); + + jsonw_uint_field(json_wtr, "prog_id", info->prog_id); +} + +static int get_prog_info(int prog_id, struct bpf_prog_info *info) +{ + __u32 len = sizeof(*info); + int err, prog_fd; + + prog_fd = bpf_prog_get_fd_by_id(prog_id); + if (prog_fd < 0) + return prog_fd; + + memset(info, 0, sizeof(*info)); + err = bpf_obj_get_info_by_fd(prog_fd, info, &len); + if (err) + p_err("can't get prog info: %s", strerror(errno)); + close(prog_fd); + return err; +} + +static int show_link_close_json(int fd, struct bpf_link_info *info) +{ + struct bpf_prog_info prog_info; + int err; + + jsonw_start_object(json_wtr); + + show_link_header_json(info, json_wtr); + + switch (info->type) { + case BPF_LINK_TYPE_RAW_TRACEPOINT: + jsonw_string_field(json_wtr, "tp_name", + (const char *)info->raw_tracepoint.tp_name); + break; + case BPF_LINK_TYPE_TRACING: + err = get_prog_info(info->prog_id, &prog_info); + if (err) + return err; + + if (prog_info.type < ARRAY_SIZE(prog_type_name)) + jsonw_string_field(json_wtr, "prog_type", + prog_type_name[prog_info.type]); + else + jsonw_uint_field(json_wtr, "prog_type", + prog_info.type); + + if (info->tracing.attach_type < ARRAY_SIZE(attach_type_name)) + jsonw_string_field(json_wtr, "attach_type", + attach_type_name[info->tracing.attach_type]); + else + jsonw_uint_field(json_wtr, "attach_type", + info->tracing.attach_type); + break; + case BPF_LINK_TYPE_CGROUP: + jsonw_lluint_field(json_wtr, "cgroup_id", + info->cgroup.cgroup_id); + if (info->cgroup.attach_type < ARRAY_SIZE(attach_type_name)) + jsonw_string_field(json_wtr, "attach_type", + attach_type_name[info->cgroup.attach_type]); + else + jsonw_uint_field(json_wtr, "attach_type", + info->cgroup.attach_type); + break; + default: + break; + } + + if (!hash_empty(link_table.table)) { + struct pinned_obj *obj; + + jsonw_name(json_wtr, "pinned"); + jsonw_start_array(json_wtr); + hash_for_each_possible(link_table.table, obj, hash, info->id) { + if (obj->id == info->id) + jsonw_string(json_wtr, obj->path); + } + jsonw_end_array(json_wtr); + } + jsonw_end_object(json_wtr); + + return 0; +} + +static void show_link_header_plain(struct bpf_link_info *info) +{ + printf("%u: ", info->id); + if (info->type < ARRAY_SIZE(link_type_name)) + printf("%s ", link_type_name[info->type]); + else + printf("type %u ", info->type); + + printf("prog %u ", info->prog_id); +} + +static int show_link_close_plain(int fd, struct bpf_link_info *info) +{ + struct bpf_prog_info prog_info; + int err; + + show_link_header_plain(info); + + switch (info->type) { + case BPF_LINK_TYPE_RAW_TRACEPOINT: + printf("\n\ttp '%s' ", + (const char *)info->raw_tracepoint.tp_name); + break; + case BPF_LINK_TYPE_TRACING: + err = get_prog_info(info->prog_id, &prog_info); + if (err) + return err; + + if (prog_info.type < ARRAY_SIZE(prog_type_name)) + printf("\n\tprog_type %s ", + prog_type_name[prog_info.type]); + else + printf("\n\tprog_type %u ", prog_info.type); + + if (info->tracing.attach_type < ARRAY_SIZE(attach_type_name)) + printf("attach_type %s ", + attach_type_name[info->tracing.attach_type]); + else + printf("attach_type %u ", info->tracing.attach_type); + break; + case BPF_LINK_TYPE_CGROUP: + printf("\n\tcgroup_id %zu ", (size_t)info->cgroup.cgroup_id); + if (info->cgroup.attach_type < ARRAY_SIZE(attach_type_name)) + printf("attach_type %s ", + attach_type_name[info->cgroup.attach_type]); + else + printf("attach_type %u ", info->cgroup.attach_type); + break; + default: + break; + } + + if (!hash_empty(link_table.table)) { + struct pinned_obj *obj; + + hash_for_each_possible(link_table.table, obj, hash, info->id) { + if (obj->id == info->id) + printf("\n\tpinned %s", obj->path); + } + } + + printf("\n"); + + return 0; +} + +static int do_show_link(int fd) +{ + struct bpf_link_info info; + __u32 len = sizeof(info); + char raw_tp_name[256]; + int err; + + memset(&info, 0, sizeof(info)); +again: + err = bpf_obj_get_info_by_fd(fd, &info, &len); + if (err) { + p_err("can't get link info: %s", + strerror(errno)); + close(fd); + return err; + } + if (info.type == BPF_LINK_TYPE_RAW_TRACEPOINT && + !info.raw_tracepoint.tp_name) { + info.raw_tracepoint.tp_name = (unsigned long)&raw_tp_name; + info.raw_tracepoint.tp_name_len = sizeof(raw_tp_name); + goto again; + } + + if (json_output) + show_link_close_json(fd, &info); + else + show_link_close_plain(fd, &info); + + close(fd); + return 0; +} + +static int do_show(int argc, char **argv) +{ + __u32 id = 0; + int err, fd; + + if (show_pinned) + build_pinned_obj_table(&link_table, BPF_OBJ_LINK); + + if (argc == 2) { + fd = link_parse_fd(&argc, &argv); + if (fd < 0) + return fd; + return do_show_link(fd); + } + + if (argc) + return BAD_ARG(); + + if (json_output) + jsonw_start_array(json_wtr); + while (true) { + err = bpf_link_get_next_id(id, &id); + if (err) { + if (errno == ENOENT) + break; + p_err("can't get next link: %s%s", strerror(errno), + errno == EINVAL ? " -- kernel too old?" : ""); + break; + } + + fd = bpf_link_get_fd_by_id(id); + if (fd < 0) { + if (errno == ENOENT) + continue; + p_err("can't get link by id (%u): %s", + id, strerror(errno)); + break; + } + + err = do_show_link(fd); + if (err) + break; + } + if (json_output) + jsonw_end_array(json_wtr); + + return errno == ENOENT ? 0 : -1; +} + +static int do_pin(int argc, char **argv) +{ + int err; + + err = do_pin_any(argc, argv, link_parse_fd); + if (!err && json_output) + jsonw_null(json_wtr); + return err; +} + +static int do_help(int argc, char **argv) +{ + if (json_output) { + jsonw_null(json_wtr); + return 0; + } + + fprintf(stderr, + "Usage: %1$s %2$s { show | list } [LINK]\n" + " %1$s %2$s pin LINK FILE\n" + " %1$s %2$s help\n" + "\n" + " " HELP_SPEC_LINK "\n" + " " HELP_SPEC_PROGRAM "\n" + " " HELP_SPEC_OPTIONS "\n" + "", + bin_name, argv[-2]); + + return 0; +} + +static const struct cmd cmds[] = { + { "show", do_show }, + { "list", do_show }, + { "help", do_help }, + { "pin", do_pin }, + { 0 } +}; + +int do_link(int argc, char **argv) +{ + return cmd_select(cmds, argc, argv, do_help); +} diff --git a/tools/bpf/bpftool/main.c b/tools/bpf/bpftool/main.c index 466c269eabdd8a28564788402bbefa0ffac7a020..1413a154806ec073757b207e5966d6dccebcda96 100644 --- a/tools/bpf/bpftool/main.c +++ b/tools/bpf/bpftool/main.c @@ -30,6 +30,7 @@ bool verifier_logs; bool relaxed_maps; struct pinned_obj_table prog_table; struct pinned_obj_table map_table; +struct pinned_obj_table link_table; static void __noreturn clean_and_exit(int i) { @@ -58,7 +59,7 @@ static int do_help(int argc, char **argv) " %s batch file FILE\n" " %s version\n" "\n" - " OBJECT := { prog | map | cgroup | perf | net | feature | btf | gen | struct_ops }\n" + " OBJECT := { prog | map | link | cgroup | perf | net | feature | btf | gen | struct_ops }\n" " " HELP_SPEC_OPTIONS "\n" "", bin_name, bin_name, bin_name); @@ -215,6 +216,7 @@ static const struct cmd cmds[] = { { "batch", do_batch }, { "prog", do_prog }, { "map", do_map }, + { "link", do_link }, { "cgroup", do_cgroup }, { "perf", do_perf }, { "net", do_net }, @@ -364,6 +366,7 @@ int main(int argc, char **argv) hash_init(prog_table.table); hash_init(map_table.table); + hash_init(link_table.table); opterr = 0; while ((opt = getopt_long(argc, argv, "Vhpjfmnd", @@ -422,6 +425,7 @@ int main(int argc, char **argv) if (show_pinned) { delete_pinned_obj_table(&prog_table); delete_pinned_obj_table(&map_table); + delete_pinned_obj_table(&link_table); } return ret; diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h index 86f14ce26fd7013aa0d931dfac9a66973cf7abc3..9b1fb81a833117d75664b0a512f51dfe2f6f6cca 100644 --- a/tools/bpf/bpftool/main.h +++ b/tools/bpf/bpftool/main.h @@ -50,6 +50,8 @@ "\t {-m|--mapcompat} | {-n|--nomount} }" #define HELP_SPEC_MAP \ "MAP := { id MAP_ID | pinned FILE | name MAP_NAME }" +#define HELP_SPEC_LINK \ + "LINK := { id LINK_ID | pinned FILE }" static const char * const prog_type_name[] = { [BPF_PROG_TYPE_UNSPEC] = "unspec", @@ -83,6 +85,38 @@ static const char * const prog_type_name[] = { [BPF_PROG_TYPE_EXT] = "ext", }; +static const char * const attach_type_name[__MAX_BPF_ATTACH_TYPE] = { + [BPF_CGROUP_INET_INGRESS] = "ingress", + [BPF_CGROUP_INET_EGRESS] = "egress", + [BPF_CGROUP_INET_SOCK_CREATE] = "sock_create", + [BPF_CGROUP_SOCK_OPS] = "sock_ops", + [BPF_CGROUP_DEVICE] = "device", + [BPF_CGROUP_INET4_BIND] = "bind4", + [BPF_CGROUP_INET6_BIND] = "bind6", + [BPF_CGROUP_INET4_CONNECT] = "connect4", + [BPF_CGROUP_INET6_CONNECT] = "connect6", + [BPF_CGROUP_INET4_POST_BIND] = "post_bind4", + [BPF_CGROUP_INET6_POST_BIND] = "post_bind6", + [BPF_CGROUP_UDP4_SENDMSG] = "sendmsg4", + [BPF_CGROUP_UDP6_SENDMSG] = "sendmsg6", + [BPF_CGROUP_SYSCTL] = "sysctl", + [BPF_CGROUP_UDP4_RECVMSG] = "recvmsg4", + [BPF_CGROUP_UDP6_RECVMSG] = "recvmsg6", + [BPF_CGROUP_GETSOCKOPT] = "getsockopt", + [BPF_CGROUP_SETSOCKOPT] = "setsockopt", + + [BPF_SK_SKB_STREAM_PARSER] = "sk_skb_stream_parser", + [BPF_SK_SKB_STREAM_VERDICT] = "sk_skb_stream_verdict", + [BPF_SK_MSG_VERDICT] = "sk_msg_verdict", + [BPF_LIRC_MODE2] = "lirc_mode2", + [BPF_FLOW_DISSECTOR] = "flow_dissector", + [BPF_TRACE_RAW_TP] = "raw_tp", + [BPF_TRACE_FENTRY] = "fentry", + [BPF_TRACE_FEXIT] = "fexit", + [BPF_MODIFY_RETURN] = "mod_ret", + [BPF_LSM_MAC] = "lsm_mac", +}; + extern const char * const map_type_name[]; extern const size_t map_type_name_size; @@ -90,6 +124,7 @@ enum bpf_obj_type { BPF_OBJ_UNKNOWN, BPF_OBJ_PROG, BPF_OBJ_MAP, + BPF_OBJ_LINK, }; extern const char *bin_name; @@ -102,6 +137,7 @@ extern bool verifier_logs; extern bool relaxed_maps; extern struct pinned_obj_table prog_table; extern struct pinned_obj_table map_table; +extern struct pinned_obj_table link_table; void __printf(1, 2) p_err(const char *fmt, ...); void __printf(1, 2) p_info(const char *fmt, ...); @@ -153,6 +189,7 @@ int do_pin_fd(int fd, const char *name); int do_prog(int argc, char **arg); int do_map(int argc, char **arg); +int do_link(int argc, char **arg); int do_event_pipe(int argc, char **argv); int do_cgroup(int argc, char **arg); int do_perf(int argc, char **arg); diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 4a6c47f3febea1dddcfda17c8e3ee868e424c5cc..0eccafae55bbc1b589a22e6308cbc4557d04f74a 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -113,6 +113,8 @@ enum bpf_cmd { BPF_MAP_DELETE_BATCH, BPF_LINK_CREATE, BPF_LINK_UPDATE, + BPF_LINK_GET_FD_BY_ID, + BPF_LINK_GET_NEXT_ID, }; enum bpf_map_type { @@ -220,6 +222,15 @@ enum bpf_attach_type { #define MAX_BPF_ATTACH_TYPE __MAX_BPF_ATTACH_TYPE +enum bpf_link_type { + BPF_LINK_TYPE_UNSPEC = 0, + BPF_LINK_TYPE_RAW_TRACEPOINT = 1, + BPF_LINK_TYPE_TRACING = 2, + BPF_LINK_TYPE_CGROUP = 3, + + MAX_BPF_LINK_TYPE, +}; + /* cgroup-bpf attach flags used in BPF_PROG_ATTACH command * * NONE(default): No further bpf programs allowed in the subtree. @@ -523,6 +534,7 @@ union bpf_attr { __u32 prog_id; __u32 map_id; __u32 btf_id; + __u32 link_id; }; __u32 next_id; __u32 open_flags; @@ -3609,6 +3621,25 @@ struct bpf_btf_info { __u32 id; } __attribute__((aligned(8))); +struct bpf_link_info { + __u32 type; + __u32 id; + __u32 prog_id; + union { + struct { + __aligned_u64 tp_name; /* in/out: tp_name buffer ptr */ + __u32 tp_name_len; /* in/out: tp_name buffer len */ + } raw_tracepoint; + struct { + __u32 attach_type; + } tracing; + struct { + __u64 cgroup_id; + __u32 attach_type; + } cgroup; + }; +} __attribute__((aligned(8))); + /* User bpf_sock_addr struct to access socket fields and sockaddr struct passed * by user and intended to be used by socket (e.g. to bind to, depends on * attach attach type). diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c index 5cc1b0785d187f354c17fce3f3e4805776f47c55..8f2f0958d446a449f67ae396e4f57c2cca63ebdf 100644 --- a/tools/lib/bpf/bpf.c +++ b/tools/lib/bpf/bpf.c @@ -721,6 +721,11 @@ int bpf_btf_get_next_id(__u32 start_id, __u32 *next_id) return bpf_obj_get_next_id(start_id, next_id, BPF_BTF_GET_NEXT_ID); } +int bpf_link_get_next_id(__u32 start_id, __u32 *next_id) +{ + return bpf_obj_get_next_id(start_id, next_id, BPF_LINK_GET_NEXT_ID); +} + int bpf_prog_get_fd_by_id(__u32 id) { union bpf_attr attr; @@ -751,13 +756,23 @@ int bpf_btf_get_fd_by_id(__u32 id) return sys_bpf(BPF_BTF_GET_FD_BY_ID, &attr, sizeof(attr)); } -int bpf_obj_get_info_by_fd(int prog_fd, void *info, __u32 *info_len) +int bpf_link_get_fd_by_id(__u32 id) +{ + union bpf_attr attr; + + memset(&attr, 0, sizeof(attr)); + attr.link_id = id; + + return sys_bpf(BPF_LINK_GET_FD_BY_ID, &attr, sizeof(attr)); +} + +int bpf_obj_get_info_by_fd(int bpf_fd, void *info, __u32 *info_len) { union bpf_attr attr; int err; memset(&attr, 0, sizeof(attr)); - attr.info.bpf_fd = prog_fd; + attr.info.bpf_fd = bpf_fd; attr.info.info_len = *info_len; attr.info.info = ptr_to_u64(info); diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h index 46d47afdd8877a61c644db603d54f36dd5650142..335b457b3a25d08bba5f3776840e5ba7d0fef128 100644 --- a/tools/lib/bpf/bpf.h +++ b/tools/lib/bpf/bpf.h @@ -216,10 +216,12 @@ LIBBPF_API int bpf_prog_test_run(int prog_fd, int repeat, void *data, LIBBPF_API int bpf_prog_get_next_id(__u32 start_id, __u32 *next_id); LIBBPF_API int bpf_map_get_next_id(__u32 start_id, __u32 *next_id); LIBBPF_API int bpf_btf_get_next_id(__u32 start_id, __u32 *next_id); +LIBBPF_API int bpf_link_get_next_id(__u32 start_id, __u32 *next_id); LIBBPF_API int bpf_prog_get_fd_by_id(__u32 id); LIBBPF_API int bpf_map_get_fd_by_id(__u32 id); LIBBPF_API int bpf_btf_get_fd_by_id(__u32 id); -LIBBPF_API int bpf_obj_get_info_by_fd(int prog_fd, void *info, __u32 *info_len); +LIBBPF_API int bpf_link_get_fd_by_id(__u32 id); +LIBBPF_API int bpf_obj_get_info_by_fd(int bpf_fd, void *info, __u32 *info_len); LIBBPF_API int bpf_prog_query(int target_fd, enum bpf_attach_type type, __u32 query_flags, __u32 *attach_flags, __u32 *prog_ids, __u32 *prog_cnt); diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index bb8831605b25889c1fd6f2dd08b0f5f37bffe9cf..7cd49aa380057ee167eaaa34a2daf7c95a9f062e 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -254,3 +254,9 @@ LIBBPF_0.0.8 { bpf_program__set_lsm; bpf_set_link_xdp_fd_opts; } LIBBPF_0.0.7; + +LIBBPF_0.0.9 { + global: + bpf_link_get_fd_by_id; + bpf_link_get_next_id; +} LIBBPF_0.0.8; diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_obj_id.c b/tools/testing/selftests/bpf/prog_tests/bpf_obj_id.c index f10029821e1672f7038bc8f86ae43c393835b8f4..7afa4160416f6a649cc41d9d171567341acc8fe4 100644 --- a/tools/testing/selftests/bpf/prog_tests/bpf_obj_id.c +++ b/tools/testing/selftests/bpf/prog_tests/bpf_obj_id.c @@ -1,26 +1,30 @@ // SPDX-License-Identifier: GPL-2.0 #include +#define nr_iters 2 + void test_bpf_obj_id(void) { const __u64 array_magic_value = 0xfaceb00c; const __u32 array_key = 0; - const int nr_iters = 2; const char *file = "./test_obj_id.o"; const char *expected_prog_name = "test_obj_id"; const char *expected_map_name = "test_map_id"; const __u64 nsec_per_sec = 1000000000; - struct bpf_object *objs[nr_iters]; + struct bpf_object *objs[nr_iters] = {}; + struct bpf_link *links[nr_iters] = {}; + struct bpf_program *prog; int prog_fds[nr_iters], map_fds[nr_iters]; /* +1 to test for the info_len returned by kernel */ struct bpf_prog_info prog_infos[nr_iters + 1]; struct bpf_map_info map_infos[nr_iters + 1]; + struct bpf_link_info link_infos[nr_iters + 1]; /* Each prog only uses one map. +1 to test nr_map_ids * returned by kernel. */ __u32 map_ids[nr_iters + 1]; - char jited_insns[128], xlated_insns[128], zeros[128]; + char jited_insns[128], xlated_insns[128], zeros[128], tp_name[128]; __u32 i, next_id, info_len, nr_id_found, duration = 0; struct timespec real_time_ts, boot_time_ts; int err = 0; @@ -36,14 +40,15 @@ void test_bpf_obj_id(void) CHECK(err >= 0 || errno != ENOENT, "get-fd-by-notexist-map-id", "err %d errno %d\n", err, errno); - for (i = 0; i < nr_iters; i++) - objs[i] = NULL; + err = bpf_link_get_fd_by_id(0); + CHECK(err >= 0 || errno != ENOENT, + "get-fd-by-notexist-link-id", "err %d errno %d\n", err, errno); /* Check bpf_obj_get_info_by_fd() */ bzero(zeros, sizeof(zeros)); for (i = 0; i < nr_iters; i++) { now = time(NULL); - err = bpf_prog_load(file, BPF_PROG_TYPE_SOCKET_FILTER, + err = bpf_prog_load(file, BPF_PROG_TYPE_RAW_TRACEPOINT, &objs[i], &prog_fds[i]); /* test_obj_id.o is a dumb prog. It should never fail * to load. @@ -60,6 +65,17 @@ void test_bpf_obj_id(void) if (CHECK_FAIL(err)) goto done; + prog = bpf_object__find_program_by_title(objs[i], + "raw_tp/sys_enter"); + if (CHECK_FAIL(!prog)) + goto done; + links[i] = bpf_program__attach(prog); + err = libbpf_get_error(links[i]); + if (CHECK(err, "prog_attach", "prog #%d, err %d\n", i, err)) { + links[i] = NULL; + goto done; + } + /* Check getting map info */ info_len = sizeof(struct bpf_map_info) * 2; bzero(&map_infos[i], info_len); @@ -107,7 +123,7 @@ void test_bpf_obj_id(void) load_time = (real_time_ts.tv_sec - boot_time_ts.tv_sec) + (prog_infos[i].load_time / nsec_per_sec); if (CHECK(err || - prog_infos[i].type != BPF_PROG_TYPE_SOCKET_FILTER || + prog_infos[i].type != BPF_PROG_TYPE_RAW_TRACEPOINT || info_len != sizeof(struct bpf_prog_info) || (env.jit_enabled && !prog_infos[i].jited_prog_len) || (env.jit_enabled && @@ -120,7 +136,11 @@ void test_bpf_obj_id(void) *(int *)(long)prog_infos[i].map_ids != map_infos[i].id || strcmp((char *)prog_infos[i].name, expected_prog_name), "get-prog-info(fd)", - "err %d errno %d i %d type %d(%d) info_len %u(%zu) jit_enabled %d jited_prog_len %u xlated_prog_len %u jited_prog %d xlated_prog %d load_time %lu(%lu) uid %u(%u) nr_map_ids %u(%u) map_id %u(%u) name %s(%s)\n", + "err %d errno %d i %d type %d(%d) info_len %u(%zu) " + "jit_enabled %d jited_prog_len %u xlated_prog_len %u " + "jited_prog %d xlated_prog %d load_time %lu(%lu) " + "uid %u(%u) nr_map_ids %u(%u) map_id %u(%u) " + "name %s(%s)\n", err, errno, i, prog_infos[i].type, BPF_PROG_TYPE_SOCKET_FILTER, info_len, sizeof(struct bpf_prog_info), @@ -135,6 +155,33 @@ void test_bpf_obj_id(void) *(int *)(long)prog_infos[i].map_ids, map_infos[i].id, prog_infos[i].name, expected_prog_name)) goto done; + + /* Check getting link info */ + info_len = sizeof(struct bpf_link_info) * 2; + bzero(&link_infos[i], info_len); + link_infos[i].raw_tracepoint.tp_name = (__u64)&tp_name; + link_infos[i].raw_tracepoint.tp_name_len = sizeof(tp_name); + err = bpf_obj_get_info_by_fd(bpf_link__fd(links[i]), + &link_infos[i], &info_len); + if (CHECK(err || + link_infos[i].type != BPF_LINK_TYPE_RAW_TRACEPOINT || + link_infos[i].prog_id != prog_infos[i].id || + link_infos[i].raw_tracepoint.tp_name != (__u64)&tp_name || + strcmp((char *)link_infos[i].raw_tracepoint.tp_name, + "sys_enter") || + info_len != sizeof(struct bpf_link_info), + "get-link-info(fd)", + "err %d errno %d info_len %u(%zu) type %d(%d) id %d " + "prog_id %d (%d) tp_name %s(%s)\n", + err, errno, + info_len, sizeof(struct bpf_link_info), + link_infos[i].type, BPF_LINK_TYPE_RAW_TRACEPOINT, + link_infos[i].id, + link_infos[i].prog_id, prog_infos[i].id, + (char *)link_infos[i].raw_tracepoint.tp_name, + "sys_enter")) + goto done; + } /* Check bpf_prog_get_next_id() */ @@ -247,7 +294,52 @@ void test_bpf_obj_id(void) "nr_id_found %u(%u)\n", nr_id_found, nr_iters); + /* Check bpf_link_get_next_id() */ + nr_id_found = 0; + next_id = 0; + while (!bpf_link_get_next_id(next_id, &next_id)) { + struct bpf_link_info link_info; + int link_fd, cmp_res; + + info_len = sizeof(link_info); + memset(&link_info, 0, info_len); + + link_fd = bpf_link_get_fd_by_id(next_id); + if (link_fd < 0 && errno == ENOENT) + /* The bpf_link is in the dead row */ + continue; + if (CHECK(link_fd < 0, "get-link-fd(next_id)", + "link_fd %d next_id %u errno %d\n", + link_fd, next_id, errno)) + break; + + for (i = 0; i < nr_iters; i++) + if (link_infos[i].id == next_id) + break; + + if (i == nr_iters) + continue; + + nr_id_found++; + + err = bpf_obj_get_info_by_fd(link_fd, &link_info, &info_len); + cmp_res = memcmp(&link_info, &link_infos[i], + offsetof(struct bpf_link_info, raw_tracepoint)); + CHECK(err || info_len != sizeof(link_info) || cmp_res, + "check get-link-info(next_id->fd)", + "err %d errno %d info_len %u(%zu) memcmp %d\n", + err, errno, info_len, sizeof(struct bpf_link_info), + cmp_res); + + close(link_fd); + } + CHECK(nr_id_found != nr_iters, + "check total link id found by get_next_id", + "nr_id_found %u(%u)\n", nr_id_found, nr_iters); + done: - for (i = 0; i < nr_iters; i++) + for (i = 0; i < nr_iters; i++) { + bpf_link__destroy(links[i]); bpf_object__close(objs[i]); + } } diff --git a/tools/testing/selftests/bpf/progs/test_obj_id.c b/tools/testing/selftests/bpf/progs/test_obj_id.c index 98b9de2fafd00bc2886cf7142fc35c43ca3ed489..ded71b3ff6b4760df2dcbe970c5ac52b31a6dcaa 100644 --- a/tools/testing/selftests/bpf/progs/test_obj_id.c +++ b/tools/testing/selftests/bpf/progs/test_obj_id.c @@ -3,16 +3,8 @@ */ #include #include -#include #include -/* It is a dumb bpf program such that it must have no - * issue to be loaded since testing the verifier is - * not the focus here. - */ - -int _version SEC("version") = 1; - struct { __uint(type, BPF_MAP_TYPE_ARRAY); __uint(max_entries, 1); @@ -20,13 +12,13 @@ struct { __type(value, __u64); } test_map_id SEC(".maps"); -SEC("test_obj_id_dummy") -int test_obj_id(struct __sk_buff *skb) +SEC("raw_tp/sys_enter") +int test_obj_id(void *ctx) { __u32 key = 0; __u64 *value; value = bpf_map_lookup_elem(&test_map_id, &key); - return TC_ACT_OK; + return 0; }