| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <20250313233615.2329869-2-jrife@google.com>
Date: Thu, 13 Mar 2025 23:35:25 +0000
From: Jordan Rife <jrife@...gle.com>
To: netdev@...r.kernel.org, bpf@...r.kernel.org
Cc: Jordan Rife <jrife@...gle.com>, Daniel Borkmann <daniel@...earbox.net>,
Martin KaFai Lau <martin.lau@...ux.dev>, Yonghong Song <yonghong.song@...ux.dev>,
Aditi Ghag <aditi.ghag@...valent.com>
Subject: [RFC PATCH bpf-next 1/3] bpf: udp: Avoid socket skips during iteration
Replace the offset-based approach for tracking progress through a bucket
in the UDP table with one based on unique, monotonically increasing
index numbers associated with each socket in a bucket.
Signed-off-by: Jordan Rife <jrife@...gle.com>
---
include/net/sock.h | 2 ++
include/net/udp.h | 1 +
net/ipv4/udp.c | 38 +++++++++++++++++++++++++-------------
3 files changed, 28 insertions(+), 13 deletions(-)
diff --git a/include/net/sock.h b/include/net/sock.h
index 8036b3b79cd8..b11f43e8e7ec 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -228,6 +228,7 @@ struct sock_common {
u32 skc_window_clamp;
u32 skc_tw_snd_nxt; /* struct tcp_timewait_sock */
};
+ __s64 skc_idx;
/* public: */
};
@@ -378,6 +379,7 @@ struct sock {
#define sk_incoming_cpu __sk_common.skc_incoming_cpu
#define sk_flags __sk_common.skc_flags
#define sk_rxhash __sk_common.skc_rxhash
+#define sk_idx __sk_common.skc_idx
__cacheline_group_begin(sock_write_rx);
diff --git a/include/net/udp.h b/include/net/udp.h
index 6e89520e100d..9398561addc6 100644
--- a/include/net/udp.h
+++ b/include/net/udp.h
@@ -102,6 +102,7 @@ struct udp_table {
#endif
unsigned int mask;
unsigned int log;
+ atomic64_t ver;
};
extern struct udp_table udp_table;
void udp_table_init(struct udp_table *, const char *);
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index a9bb9ce5438e..d7e9b3346983 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -229,6 +229,11 @@ static int udp_reuseport_add_sock(struct sock *sk, struct udp_hslot *hslot)
return reuseport_alloc(sk, inet_rcv_saddr_any(sk));
}
+static inline __s64 udp_table_next_idx(struct udp_table *udptable, bool pos)
+{
+ return (pos ? 1 : -1) * atomic64_inc_return(&udptable->ver);
+}
+
/**
* udp_lib_get_port - UDP/-Lite port lookup for IPv4 and IPv6
*
@@ -244,6 +249,7 @@ int udp_lib_get_port(struct sock *sk, unsigned short snum,
struct udp_hslot *hslot, *hslot2;
struct net *net = sock_net(sk);
int error = -EADDRINUSE;
+ bool add_tail;
if (!snum) {
DECLARE_BITMAP(bitmap, PORTS_PER_CHAIN);
@@ -335,14 +341,16 @@ int udp_lib_get_port(struct sock *sk, unsigned short snum,
hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
spin_lock(&hslot2->lock);
- if (IS_ENABLED(CONFIG_IPV6) && sk->sk_reuseport &&
- sk->sk_family == AF_INET6)
+ add_tail = IS_ENABLED(CONFIG_IPV6) && sk->sk_reuseport &&
+ sk->sk_family == AF_INET6;
+ if (add_tail)
hlist_add_tail_rcu(&udp_sk(sk)->udp_portaddr_node,
&hslot2->head);
else
hlist_add_head_rcu(&udp_sk(sk)->udp_portaddr_node,
&hslot2->head);
hslot2->count++;
+ sk->sk_idx = udp_table_next_idx(udptable, add_tail);
spin_unlock(&hslot2->lock);
}
@@ -2250,6 +2258,8 @@ void udp_lib_rehash(struct sock *sk, u16 newhash, u16 newhash4)
hlist_add_head_rcu(&udp_sk(sk)->udp_portaddr_node,
&nhslot2->head);
nhslot2->count++;
+ sk->sk_idx = udp_table_next_idx(udptable,
+ false);
spin_unlock(&nhslot2->lock);
}
@@ -3390,9 +3400,9 @@ struct bpf_udp_iter_state {
unsigned int cur_sk;
unsigned int end_sk;
unsigned int max_sk;
- int offset;
struct sock **batch;
bool st_bucket_done;
+ __s64 prev_idx;
};
static int bpf_iter_udp_realloc_batch(struct bpf_udp_iter_state *iter,
@@ -3402,14 +3412,13 @@ static struct sock *bpf_iter_udp_batch(struct seq_file *seq)
struct bpf_udp_iter_state *iter = seq->private;
struct udp_iter_state *state = &iter->state;
struct net *net = seq_file_net(seq);
- int resume_bucket, resume_offset;
struct udp_table *udptable;
unsigned int batch_sks = 0;
bool resized = false;
+ int resume_bucket;
struct sock *sk;
resume_bucket = state->bucket;
- resume_offset = iter->offset;
/* The current batch is done, so advance the bucket. */
if (iter->st_bucket_done)
@@ -3436,18 +3445,19 @@ static struct sock *bpf_iter_udp_batch(struct seq_file *seq)
if (hlist_empty(&hslot2->head))
continue;
- iter->offset = 0;
spin_lock_bh(&hslot2->lock);
+ /* Reset prev_idx if this is a new bucket. */
+ if (!resume_bucket || state->bucket != resume_bucket)
+ iter->prev_idx = 0;
udp_portaddr_for_each_entry(sk, &hslot2->head) {
if (seq_sk_match(seq, sk)) {
- /* Resume from the last iterated socket at the
- * offset in the bucket before iterator was stopped.
+ /* Resume from the first socket that we didn't
+ * see last time around.
*/
if (state->bucket == resume_bucket &&
- iter->offset < resume_offset) {
- ++iter->offset;
+ iter->prev_idx &&
+ sk->sk_idx <= iter->prev_idx)
continue;
- }
if (iter->end_sk < iter->max_sk) {
sock_hold(sk);
iter->batch[iter->end_sk++] = sk;
@@ -3492,8 +3502,9 @@ static void *bpf_iter_udp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
* done with seq_show(), so unref the iter->cur_sk.
*/
if (iter->cur_sk < iter->end_sk) {
- sock_put(iter->batch[iter->cur_sk++]);
- ++iter->offset;
+ sk = iter->batch[iter->cur_sk++];
+ iter->prev_idx = sk->sk_idx;
+ sock_put(sk);
}
/* After updating iter->cur_sk, check if there are more sockets
@@ -3740,6 +3751,7 @@ static struct udp_table __net_init *udp_pernet_table_alloc(unsigned int hash_ent
udptable->hash2 = (void *)(udptable->hash + hash_entries);
udptable->mask = hash_entries - 1;
udptable->log = ilog2(hash_entries);
+ atomic64_set(&udptable->ver, 0);
for (i = 0; i < hash_entries; i++) {
INIT_HLIST_HEAD(&udptable->hash[i].head);
--
2.49.0.rc1.451.g8f38331e32-goog
Powered by blists - more mailing lists