diff mbox series

[RFC,bpf-next,v2,07/17] bpf: add netlink and ipv6_route targets

Message ID 20200415192748.4083243-1-yhs@fb.com
State New
Headers show
Series bpf: implement bpf based dumping of kernel data structures | expand

Commit Message

Yonghong Song April 15, 2020, 7:27 p.m. UTC 
This patch added netlink and ipv6_route targets, using
the same seq_ops (except show()) for /proc/net/{netlink,ipv6_route}.

Since module is not supported for now, ipv6_route is
supported only if the IPV6 is built-in, i.e., not compiled
as a module. The restriction can be lifted once module
is properly supported for bpfdump.

Signed-off-by: Yonghong Song <yhs@fb.com>
---
 include/linux/bpf.h      |  8 +++-
 kernel/bpf/dump.c        | 13 ++++++
 net/ipv6/ip6_fib.c       | 71 +++++++++++++++++++++++++++++-
 net/ipv6/route.c         | 29 +++++++++++++
 net/netlink/af_netlink.c | 94 +++++++++++++++++++++++++++++++++++++++-
 5 files changed, 210 insertions(+), 5 deletions(-)
diff mbox series

Patch

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 1179ca3d0230..401e5bf921a2 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1124,6 +1124,12 @@  struct bpf_dump_reg {
 	u32 target_feature;
 };
 
+struct bpf_dump_meta {
+	struct seq_file *seq;
+	u64 session_id;
+	u64 seq_num;
+};
+
 int bpf_dump_reg_target(struct bpf_dump_reg *reg_info);
 int bpf_dump_set_target_info(u32 target_fd, struct bpf_prog *prog);
 int bpf_fd_dump_create(u32 prog_fd, const char __user *dumper_name,
@@ -1131,7 +1137,7 @@  int bpf_fd_dump_create(u32 prog_fd, const char __user *dumper_name,
 int bpf_prog_dump_create(struct bpf_prog *prog);
 struct bpf_prog *bpf_dump_get_prog(struct seq_file *seq, u32 priv_data_size,
 				   u64 *session_id, u64 *seq_num, bool is_last);
-
+int bpf_dump_run_prog(struct bpf_prog *prog, void *ctx);
 int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value);
 int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value);
 int bpf_percpu_hash_update(struct bpf_map *map, void *key, void *value,
diff --git a/kernel/bpf/dump.c b/kernel/bpf/dump.c
index c6d4d64aaa8e..789b35772a81 100644
--- a/kernel/bpf/dump.c
+++ b/kernel/bpf/dump.c
@@ -487,6 +487,19 @@  struct bpf_prog *bpf_dump_get_prog(struct seq_file *seq, u32 priv_data_size,
 	return extra_data->prog;
 }
 
+int bpf_dump_run_prog(struct bpf_prog *prog, void *ctx)
+{
+	int ret;
+
+	migrate_disable();
+	rcu_read_lock();
+	ret = BPF_PROG_RUN(prog, ctx);
+	rcu_read_unlock();
+	migrate_enable();
+
+	return ret;
+}
+
 int bpf_dump_reg_target(struct bpf_dump_reg *reg_info)
 {
 	struct bpfdump_target_info *tinfo, *ptinfo;
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 46ed56719476..f5a48511d233 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -2467,7 +2467,7 @@  void fib6_gc_cleanup(void)
 }
 
 #ifdef CONFIG_PROC_FS
-static int ipv6_route_seq_show(struct seq_file *seq, void *v)
+static int ipv6_route_native_seq_show(struct seq_file *seq, void *v)
 {
 	struct fib6_info *rt = v;
 	struct ipv6_route_iter *iter = seq->private;
@@ -2625,7 +2625,7 @@  static bool ipv6_route_iter_active(struct ipv6_route_iter *iter)
 	return w->node && !(w->state == FWS_U && w->node == w->root);
 }
 
-static void ipv6_route_seq_stop(struct seq_file *seq, void *v)
+static void ipv6_route_native_seq_stop(struct seq_file *seq, void *v)
 	__releases(RCU_BH)
 {
 	struct net *net = seq_file_net(seq);
@@ -2637,6 +2637,73 @@  static void ipv6_route_seq_stop(struct seq_file *seq, void *v)
 	rcu_read_unlock_bh();
 }
 
+#if IS_BUILTIN(CONFIG_IPV6) && defined(CONFIG_BPF_SYSCALL)
+struct bpfdump__ipv6_route {
+	struct bpf_dump_meta *meta;
+	struct fib6_info *rt;
+};
+
+static int ipv6_route_prog_seq_show(struct bpf_prog *prog, struct seq_file *seq,
+				    u64 session_id, u64 seq_num, void *v)
+{
+	struct bpfdump__ipv6_route ctx;
+	struct bpf_dump_meta meta;
+	int ret;
+
+	meta.seq = seq;
+	meta.session_id = session_id;
+	meta.seq_num = seq_num;
+	ctx.meta = &meta;
+	ctx.rt = v;
+	ret = bpf_dump_run_prog(prog, &ctx);
+	return ret == 0 ? 0 : -EINVAL;
+}
+
+static int ipv6_route_seq_show(struct seq_file *seq, void *v)
+{
+	struct ipv6_route_iter *iter = seq->private;
+	u64 session_id, seq_num;
+	struct bpf_prog *prog;
+	int ret;
+
+	prog = bpf_dump_get_prog(seq, sizeof(struct ipv6_route_iter),
+				 &session_id, &seq_num, false);
+	if (!prog)
+		return ipv6_route_native_seq_show(seq, v);
+
+	ret = ipv6_route_prog_seq_show(prog, seq, session_id, seq_num, v);
+	iter->w.leaf = NULL;
+
+	return ret;
+}
+
+static void ipv6_route_seq_stop(struct seq_file *seq, void *v)
+{
+	u64 session_id, seq_num;
+	struct bpf_prog *prog;
+
+	if (!v) {
+		prog = bpf_dump_get_prog(seq, sizeof(struct ipv6_route_iter),
+					 &session_id, &seq_num, true);
+		if (prog)
+			ipv6_route_prog_seq_show(prog, seq, session_id,
+						 seq_num, v);
+	}
+
+	ipv6_route_native_seq_stop(seq, v);
+}
+#else
+static int ipv6_route_seq_show(struct seq_file *seq, void *v)
+{
+	return ipv6_route_native_seq_show(seq, v);
+}
+
+static void ipv6_route_seq_stop(struct seq_file *seq, void *v)
+{
+	ipv6_route_native_seq_stop(seq, v);
+}
+#endif
+
 const struct seq_operations ipv6_route_seq_ops = {
 	.start	= ipv6_route_seq_start,
 	.next	= ipv6_route_seq_next,
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 310cbddaa533..ea87d3f2c363 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -6390,10 +6390,31 @@  void __init ip6_route_init_special_entries(void)
   #endif
 }
 
+#if IS_BUILTIN(CONFIG_IPV6)
+#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
+int __init __bpfdump__ipv6_route(struct bpf_dump_meta *meta, struct fib6_info *rt)
+{
+	return 0;
+}
+#endif
+#endif
+
 int __init ip6_route_init(void)
 {
 	int ret;
 	int cpu;
+#if IS_BUILTIN(CONFIG_IPV6)
+#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
+	struct bpf_dump_reg reg_info = {
+		.target			= "ipv6_route",
+		.target_proto		= "__bpfdump__ipv6_route",
+		.prog_ctx_type_name	= "bpfdump__ipv6_route",
+		.seq_ops		= &ipv6_route_seq_ops,
+		.seq_priv_size		= sizeof(struct ipv6_route_iter),
+		.target_feature		= BPF_DUMP_SEQ_NET_PRIVATE,
+	};
+#endif
+#endif
 
 	ret = -ENOMEM;
 	ip6_dst_ops_template.kmem_cachep =
@@ -6452,6 +6473,14 @@  int __init ip6_route_init(void)
 	if (ret)
 		goto out_register_late_subsys;
 
+#if IS_BUILTIN(CONFIG_IPV6)
+#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
+	ret = bpf_dump_reg_target(&reg_info);
+	if (ret)
+		goto out_register_late_subsys;
+#endif
+#endif
+
 	for_each_possible_cpu(cpu) {
 		struct uncached_list *ul = per_cpu_ptr(&rt6_uncached_list, cpu);
 
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 5ded01ca8b20..fe9a10642c39 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -2596,7 +2596,7 @@  static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 	return __netlink_seq_next(seq);
 }
 
-static void netlink_seq_stop(struct seq_file *seq, void *v)
+static void netlink_native_seq_stop(struct seq_file *seq, void *v)
 {
 	struct nl_seq_iter *iter = seq->private;
 
@@ -2607,7 +2607,7 @@  static void netlink_seq_stop(struct seq_file *seq, void *v)
 }
 
 
-static int netlink_seq_show(struct seq_file *seq, void *v)
+static int netlink_native_seq_show(struct seq_file *seq, void *v)
 {
 	if (v == SEQ_START_TOKEN) {
 		seq_puts(seq,
@@ -2634,6 +2634,80 @@  static int netlink_seq_show(struct seq_file *seq, void *v)
 	return 0;
 }
 
+#ifdef CONFIG_BPF_SYSCALL
+struct bpfdump__netlink {
+	struct bpf_dump_meta *meta;
+	struct netlink_sock *sk;
+};
+
+int __init __bpfdump__netlink(struct bpf_dump_meta *meta, struct netlink_sock *sk)
+{
+	return 0;
+}
+
+static int netlink_prog_seq_show(struct bpf_prog *prog, struct seq_file *seq,
+				 u64 session_id, u64 seq_num, void *v)
+{
+	struct bpfdump__netlink ctx;
+	struct bpf_dump_meta meta;
+	int ret = 0;
+
+	meta.seq = seq;
+	meta.session_id = session_id;
+	meta.seq_num = seq_num;
+	ctx.meta = &meta;
+	ctx.sk = nlk_sk((struct sock *)v);
+	ret = bpf_dump_run_prog(prog, &ctx);
+
+	return ret == 0 ? 0 : -EINVAL;
+}
+
+static int netlink_seq_show(struct seq_file *seq, void *v)
+{
+	u64 session_id, seq_num;
+	struct bpf_prog *prog;
+
+	prog = bpf_dump_get_prog(seq, sizeof(struct nl_seq_iter),
+				 &session_id, &seq_num, false);
+	if (!prog)
+		return netlink_native_seq_show(seq, v);
+
+	if (v == SEQ_START_TOKEN)
+		return 0;
+
+	return netlink_prog_seq_show(prog, seq, session_id,
+				     seq_num - 1, v);
+}
+
+static void netlink_seq_stop(struct seq_file *seq, void *v)
+{
+	u64 session_id, seq_num;
+	struct bpf_prog *prog;
+
+	if (!v) {
+		prog = bpf_dump_get_prog(seq, sizeof(struct nl_seq_iter),
+					 &session_id, &seq_num, true);
+		if (prog) {
+			if (seq_num)
+				seq_num = seq_num - 1;
+			netlink_prog_seq_show(prog, seq, session_id,
+					      seq_num, v);
+		}
+	}
+
+	netlink_native_seq_stop(seq, v);
+}
+#else
+static int netlink_seq_show(struct seq_file *seq, void *v)
+{
+	return netlink_native_seq_show(seq, v);
+}
+static void netlink_seq_stop(struct seq_file *seq, void *v)
+{
+	netlink_native_seq_stop(seq, v);
+}
+#endif
+
 static const struct seq_operations netlink_seq_ops = {
 	.start  = netlink_seq_start,
 	.next   = netlink_seq_next,
@@ -2744,6 +2818,16 @@  static int __init netlink_proto_init(void)
 {
 	int i;
 	int err = proto_register(&netlink_proto, 0);
+#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
+	struct bpf_dump_reg reg_info = {
+		.target			= "netlink",
+		.target_proto		= "__bpfdump__netlink",
+		.prog_ctx_type_name	= "bpfdump_netlink",
+		.seq_ops		= &netlink_seq_ops,
+		.seq_priv_size		= sizeof(struct nl_seq_iter),
+		.target_feature		= BPF_DUMP_SEQ_NET_PRIVATE,
+	};
+#endif
 
 	if (err != 0)
 		goto out;
@@ -2764,6 +2848,12 @@  static int __init netlink_proto_init(void)
 		}
 	}
 
+#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
+	err = bpf_dump_reg_target(&reg_info);
+	if (err)
+		goto out;
+#endif
+
 	netlink_add_usersock_entry();
 
 	sock_register(&netlink_family_ops);