From ae24345da54e452880808b011fa2d8a0bbd191ba Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Sat, 9 May 2020 10:58:59 -0700 Subject: bpf: Implement an interface to register bpf_iter targets The target can call bpf_iter_reg_target() to register itself. The needed information: target: target name seq_ops: the seq_file operations for the target init_seq_private target callback to initialize seq_priv during file open fini_seq_private target callback to clean up seq_priv during file release seq_priv_size: the private_data size needed by the seq_file operations The target name represents a target which provides a seq_ops for iterating objects. The target can provide two callback functions, init_seq_private and fini_seq_private, called during file open/release time. For example, /proc/net/{tcp6, ipv6_route, netlink, ...}, net name space needs to be setup properly during file open and released properly during file release. Function bpf_iter_unreg_target() is also implemented to unregister a particular target. Signed-off-by: Yonghong Song Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20200509175859.2474669-1-yhs@fb.com --- kernel/bpf/bpf_iter.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 59 insertions(+) create mode 100644 kernel/bpf/bpf_iter.c (limited to 'kernel/bpf/bpf_iter.c') diff --git a/kernel/bpf/bpf_iter.c b/kernel/bpf/bpf_iter.c new file mode 100644 index 000000000000..5a8119d17d14 --- /dev/null +++ b/kernel/bpf/bpf_iter.c @@ -0,0 +1,59 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Copyright (c) 2020 Facebook */ + +#include +#include +#include + +struct bpf_iter_target_info { + struct list_head list; + const char *target; + const struct seq_operations *seq_ops; + bpf_iter_init_seq_priv_t init_seq_private; + bpf_iter_fini_seq_priv_t fini_seq_private; + u32 seq_priv_size; +}; + +static struct list_head targets = LIST_HEAD_INIT(targets); +static DEFINE_MUTEX(targets_mutex); + +int bpf_iter_reg_target(struct bpf_iter_reg *reg_info) +{ + struct bpf_iter_target_info *tinfo; + + tinfo = kmalloc(sizeof(*tinfo), GFP_KERNEL); + if (!tinfo) + return -ENOMEM; + + tinfo->target = reg_info->target; + tinfo->seq_ops = reg_info->seq_ops; + tinfo->init_seq_private = reg_info->init_seq_private; + tinfo->fini_seq_private = reg_info->fini_seq_private; + tinfo->seq_priv_size = reg_info->seq_priv_size; + INIT_LIST_HEAD(&tinfo->list); + + mutex_lock(&targets_mutex); + list_add(&tinfo->list, &targets); + mutex_unlock(&targets_mutex); + + return 0; +} + +void bpf_iter_unreg_target(const char *target) +{ + struct bpf_iter_target_info *tinfo; + bool found = false; + + mutex_lock(&targets_mutex); + list_for_each_entry(tinfo, &targets, list) { + if (!strcmp(target, tinfo->target)) { + list_del(&tinfo->list); + kfree(tinfo); + found = true; + break; + } + } + mutex_unlock(&targets_mutex); + + WARN_ON(found == false); +} -- cgit v1.2.3