Skip to content

Commit

Permalink
net: bpf: Add netlink and ipv6_route bpf_iter targets
Browse files Browse the repository at this point in the history 
This patch added netlink and ipv6_route targets, using
the same seq_ops (except show() and minor changes for stop())
for /proc/net/{netlink,ipv6_route}.

The net namespace for these targets are the current net
namespace at file open stage, similar to
/proc/net/{netlink,ipv6_route} reference counting
the net namespace at seq_file open stage.

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 bpf_iter.

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200509175910.2476329-1-yhs@fb.com
  • Loading branch information
@yonghong-song
yonghong-song authored and Alexei Starovoitov committed May 10, 2020
1 parent 6086d29 commit 138d0be
Show file tree
Hide file tree
Showing 5 changed files with 207 additions and 4 deletions.
19 changes: 19 additions & 0 deletions fs/proc/proc_net.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -98,6 +98,25 @@ static const struct proc_ops proc_net_seq_ops = {
.proc_release = seq_release_net,
};

int bpf_iter_init_seq_net(void *priv_data)
{
#ifdef CONFIG_NET_NS
struct seq_net_private *p = priv_data;

p->net = get_net(current->nsproxy->net_ns);
#endif
return 0;
}

void bpf_iter_fini_seq_net(void *priv_data)
{
#ifdef CONFIG_NET_NS
struct seq_net_private *p = priv_data;

put_net(p->net);
#endif
}

struct proc_dir_entry *proc_create_net_data(const char *name, umode_t mode,
struct proc_dir_entry *parent, const struct seq_operations *ops,
unsigned int state_size, void *data)
Expand Down
3 changes: 3 additions & 0 deletions include/linux/proc_fs.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -105,6 +105,9 @@ struct proc_dir_entry *proc_create_net_single_write(const char *name, umode_t mo
void *data);
extern struct pid *tgid_pidfd_to_pid(const struct file *file);

extern int bpf_iter_init_seq_net(void *priv_data);
extern void bpf_iter_fini_seq_net(void *priv_data);

#ifdef CONFIG_PROC_PID_ARCH_STATUS
/*
* The architecture which selects CONFIG_PROC_PID_ARCH_STATUS must
Expand Down
65 changes: 63 additions & 2 deletions net/ipv6/ip6_fib.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand Down Expand Up @@ -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);
Expand All @@ -2637,6 +2637,67 @@ 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 bpf_iter__ipv6_route {
__bpf_md_ptr(struct bpf_iter_meta *, meta);
__bpf_md_ptr(struct fib6_info *, rt);
};

static int ipv6_route_prog_seq_show(struct bpf_prog *prog,
struct bpf_iter_meta *meta,
void *v)
{
struct bpf_iter__ipv6_route ctx;

ctx.meta = meta;
ctx.rt = v;
return bpf_iter_run_prog(prog, &ctx);
}

static int ipv6_route_seq_show(struct seq_file *seq, void *v)
{
struct ipv6_route_iter *iter = seq->private;
struct bpf_iter_meta meta;
struct bpf_prog *prog;
int ret;

meta.seq = seq;
prog = bpf_iter_get_info(&meta, false);
if (!prog)
return ipv6_route_native_seq_show(seq, v);

ret = ipv6_route_prog_seq_show(prog, &meta, v);
iter->w.leaf = NULL;

return ret;
}

static void ipv6_route_seq_stop(struct seq_file *seq, void *v)
{
struct bpf_iter_meta meta;
struct bpf_prog *prog;

if (!v) {
meta.seq = seq;
prog = bpf_iter_get_info(&meta, true);
if (prog)
(void)ipv6_route_prog_seq_show(prog, &meta, 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,
Expand Down
37 changes: 37 additions & 0 deletions net/ipv6/route.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -6393,6 +6393,30 @@ void __init ip6_route_init_special_entries(void)
#endif
}

#if IS_BUILTIN(CONFIG_IPV6)
#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
DEFINE_BPF_ITER_FUNC(ipv6_route, struct bpf_iter_meta *meta, struct fib6_info *rt)

static int __init bpf_iter_register(void)
{
struct bpf_iter_reg reg_info = {
.target = "ipv6_route",
.seq_ops = &ipv6_route_seq_ops,
.init_seq_private = bpf_iter_init_seq_net,
.fini_seq_private = bpf_iter_fini_seq_net,
.seq_priv_size = sizeof(struct ipv6_route_iter),
};

return bpf_iter_reg_target(&reg_info);
}

static void bpf_iter_unregister(void)
{
bpf_iter_unreg_target("ipv6_route");
}
#endif
#endif

int __init ip6_route_init(void)
{
int ret;
Expand Down Expand Up @@ -6455,6 +6479,14 @@ 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_iter_register();
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);

Expand Down Expand Up @@ -6487,6 +6519,11 @@ int __init ip6_route_init(void)

void ip6_route_cleanup(void)
{
#if IS_BUILTIN(CONFIG_IPV6)
#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
bpf_iter_unregister();
#endif
#endif
unregister_netdevice_notifier(&ip6_route_dev_notifier);
unregister_pernet_subsys(&ip6_route_net_late_ops);
fib6_rules_cleanup();
Expand Down
87 changes: 85 additions & 2 deletions net/netlink/af_netlink.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;

Expand All @@ -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,
Expand All @@ -2634,6 +2634,68 @@ static int netlink_seq_show(struct seq_file *seq, void *v)
return 0;
}

#ifdef CONFIG_BPF_SYSCALL
struct bpf_iter__netlink {
__bpf_md_ptr(struct bpf_iter_meta *, meta);
__bpf_md_ptr(struct netlink_sock *, sk);
};

DEFINE_BPF_ITER_FUNC(netlink, struct bpf_iter_meta *meta, struct netlink_sock *sk)

static int netlink_prog_seq_show(struct bpf_prog *prog,
struct bpf_iter_meta *meta,
void *v)
{
struct bpf_iter__netlink ctx;

meta->seq_num--; /* skip SEQ_START_TOKEN */
ctx.meta = meta;
ctx.sk = nlk_sk((struct sock *)v);
return bpf_iter_run_prog(prog, &ctx);
}

static int netlink_seq_show(struct seq_file *seq, void *v)
{
struct bpf_iter_meta meta;
struct bpf_prog *prog;

meta.seq = seq;
prog = bpf_iter_get_info(&meta, false);
if (!prog)
return netlink_native_seq_show(seq, v);

if (v != SEQ_START_TOKEN)
return netlink_prog_seq_show(prog, &meta, v);

return 0;
}

static void netlink_seq_stop(struct seq_file *seq, void *v)
{
struct bpf_iter_meta meta;
struct bpf_prog *prog;

if (!v) {
meta.seq = seq;
prog = bpf_iter_get_info(&meta, true);
if (prog)
(void)netlink_prog_seq_show(prog, &meta, 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,
Expand Down Expand Up @@ -2740,6 +2802,21 @@ static const struct rhashtable_params netlink_rhashtable_params = {
.automatic_shrinking = true,
};

#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
static int __init bpf_iter_register(void)
{
struct bpf_iter_reg reg_info = {
.target = "netlink",
.seq_ops = &netlink_seq_ops,
.init_seq_private = bpf_iter_init_seq_net,
.fini_seq_private = bpf_iter_fini_seq_net,
.seq_priv_size = sizeof(struct nl_seq_iter),
};

return bpf_iter_reg_target(&reg_info);
}
#endif

static int __init netlink_proto_init(void)
{
int i;
Expand All @@ -2748,6 +2825,12 @@ static int __init netlink_proto_init(void)
if (err != 0)
goto out;

#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
err = bpf_iter_register();
if (err)
goto out;
#endif

BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > sizeof_field(struct sk_buff, cb));

nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL);
Expand Down

0 comments on commit 138d0be

Please sign in to comment.