[PATCH net-next] net: bpf: add hook for close of tcp timewait sock
From: menglong8 . dong
Date: Wed Dec 29 2021 - 06:33:12 EST
From: Menglong Dong <imagedong@xxxxxxxxxxx>
The cgroup eBPF attach type 'CGROUP_SOCK_OPS' is able to monitor the
state change of a tcp connect with 'BPF_SOCK_OPS_STATE_CB' ops.
However, it can't trace the whole state change of a tcp connect. While
a connect becomes 'TCP_TIME_WAIT' state, this sock will be release and
a tw sock will be created. While tcp sock release, 'TCP_CLOSE' state
change will be passed to eBPF program. Howeven, the real state of this
connect is 'TCP_TIME_WAIT'.
To make eBPF get the real state change of a tcp connect, add
'CGROUP_TWSK_CLOSE' cgroup attach type, which will be called when
tw sock release and tcp connect become CLOSE.
Signed-off-by: Menglong Dong <imagedong@xxxxxxxxxxx>
---
include/linux/bpf-cgroup.h | 18 ++++++++++++++++++
include/net/inet_timewait_sock.h | 1 +
include/uapi/linux/bpf.h | 4 +++-
kernel/bpf/cgroup.c | 16 ++++++++++++++++
kernel/bpf/syscall.c | 3 +++
net/core/filter.c | 11 +++++++++++
net/ipv4/inet_timewait_sock.c | 4 ++++
net/ipv4/tcp_minisocks.c | 3 +++
8 files changed, 59 insertions(+), 1 deletion(-)
diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h
index 11820a430d6c..eef4d9ab7701 100644
--- a/include/linux/bpf-cgroup.h
+++ b/include/linux/bpf-cgroup.h
@@ -48,6 +48,7 @@ enum cgroup_bpf_attach_type {
CGROUP_INET4_GETSOCKNAME,
CGROUP_INET6_GETSOCKNAME,
CGROUP_INET_SOCK_RELEASE,
+ CGROUP_TWSK_CLOSE,
MAX_CGROUP_BPF_ATTACH_TYPE
};
@@ -81,6 +82,7 @@ to_cgroup_bpf_attach_type(enum bpf_attach_type attach_type)
CGROUP_ATYPE(CGROUP_INET4_GETSOCKNAME);
CGROUP_ATYPE(CGROUP_INET6_GETSOCKNAME);
CGROUP_ATYPE(CGROUP_INET_SOCK_RELEASE);
+ CGROUP_ATYPE(CGROUP_TWSK_CLOSE);
default:
return CGROUP_BPF_ATTACH_TYPE_INVALID;
}
@@ -164,6 +166,9 @@ int __cgroup_bpf_run_filter_skb(struct sock *sk,
int __cgroup_bpf_run_filter_sk(struct sock *sk,
enum cgroup_bpf_attach_type atype);
+int __cgroup_bpf_run_filter_twsk(struct sock *sk,
+ enum cgroup_bpf_attach_type atype);
+
int __cgroup_bpf_run_filter_sock_addr(struct sock *sk,
struct sockaddr *uaddr,
enum cgroup_bpf_attach_type atype,
@@ -251,6 +256,15 @@ int bpf_percpu_cgroup_storage_update(struct bpf_map *map, void *key,
__ret; \
})
+#define BPF_CGROUP_RUN_TWSK_PROG(sk, atype) \
+({ \
+ int __ret = 0; \
+ if (cgroup_bpf_enabled(atype)) { \
+ __ret = __cgroup_bpf_run_filter_twsk(sk, atype); \
+ } \
+ __ret; \
+})
+
#define BPF_CGROUP_RUN_PROG_INET_SOCK(sk) \
BPF_CGROUP_RUN_SK_PROG(sk, CGROUP_INET_SOCK_CREATE)
@@ -263,6 +277,9 @@ int bpf_percpu_cgroup_storage_update(struct bpf_map *map, void *key,
#define BPF_CGROUP_RUN_PROG_INET6_POST_BIND(sk) \
BPF_CGROUP_RUN_SK_PROG(sk, CGROUP_INET6_POST_BIND)
+#define BPF_CGROUP_RUN_PROG_TWSK_CLOSE(sk) \
+ BPF_CGROUP_RUN_TWSK_PROG(sk, CGROUP_TWSK_CLOSE)
+
#define BPF_CGROUP_RUN_SA_PROG(sk, uaddr, atype) \
({ \
u32 __unused_flags; \
@@ -524,6 +541,7 @@ static inline int bpf_percpu_cgroup_storage_update(struct bpf_map *map,
optlen, retval) ({ retval; })
#define BPF_CGROUP_RUN_PROG_SETSOCKOPT(sock, level, optname, optval, optlen, \
kernel_optval) ({ 0; })
+#define BPF_CGROUP_RUN_PROG_TWSK_CLOSE(sk) ({ 0; })
#define for_each_cgroup_storage_type(stype) for (; false; )
diff --git a/include/net/inet_timewait_sock.h b/include/net/inet_timewait_sock.h
index dfd919b3119e..7427219b0796 100644
--- a/include/net/inet_timewait_sock.h
+++ b/include/net/inet_timewait_sock.h
@@ -74,6 +74,7 @@ struct inet_timewait_sock {
u32 tw_priority;
struct timer_list tw_timer;
struct inet_bind_bucket *tw_tb;
+ struct sock_cgroup_data tw_cgrp_data;
};
#define tw_tclass tw_tos
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index c26871263f1f..641113b87f9d 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -995,6 +995,7 @@ enum bpf_attach_type {
BPF_SK_REUSEPORT_SELECT,
BPF_SK_REUSEPORT_SELECT_OR_MIGRATE,
BPF_PERF_EVENT,
+ BPF_CGROUP_TWSK_CLOSE,
__MAX_BPF_ATTACH_TYPE
};
@@ -5917,8 +5918,9 @@ enum {
* options first before the BPF program does.
*/
BPF_SOCK_OPS_WRITE_HDR_OPT_CB_FLAG = (1<<6),
+ BPF_SOCK_OPS_TW_CLOSE_FLAG = (1<<7),
/* Mask of all currently supported cb flags */
- BPF_SOCK_OPS_ALL_CB_FLAGS = 0x7F,
+ BPF_SOCK_OPS_ALL_CB_FLAGS = 0xFF,
};
/* List of known BPF sock_ops operators.
diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
index 43eb3501721b..2c32652e47d6 100644
--- a/kernel/bpf/cgroup.c
+++ b/kernel/bpf/cgroup.c
@@ -16,6 +16,7 @@
#include <linux/bpf-cgroup.h>
#include <net/sock.h>
#include <net/bpf_sk_storage.h>
+#include <net/inet_timewait_sock.h>
#include "../cgroup/cgroup-internal.h"
@@ -1114,6 +1115,21 @@ int __cgroup_bpf_run_filter_sk(struct sock *sk,
}
EXPORT_SYMBOL(__cgroup_bpf_run_filter_sk);
+int __cgroup_bpf_run_filter_twsk(struct sock *sk,
+ enum cgroup_bpf_attach_type atype)
+{
+ struct inet_timewait_sock *twsk;
+ struct cgroup *cgrp;
+ int ret;
+
+ twsk = (struct inet_timewait_sock *)sk;
+ cgrp = sock_cgroup_ptr(&twsk->tw_cgrp_data);
+
+ ret = BPF_PROG_RUN_ARRAY_CG(cgrp->bpf.effective[atype], sk, bpf_prog_run);
+ return ret == 1 ? 0 : -EPERM;
+}
+EXPORT_SYMBOL(__cgroup_bpf_run_filter_twsk);
+
/**
* __cgroup_bpf_run_filter_sock_addr() - Run a program on a sock and
* provided by user sockaddr
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index ddd81d543203..da4b6ed192f4 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -2088,6 +2088,7 @@ bpf_prog_load_check_attach(enum bpf_prog_type prog_type,
case BPF_CGROUP_INET_SOCK_RELEASE:
case BPF_CGROUP_INET4_POST_BIND:
case BPF_CGROUP_INET6_POST_BIND:
+ case BPF_CGROUP_TWSK_CLOSE:
return 0;
default:
return -EINVAL;
@@ -3140,6 +3141,7 @@ attach_type_to_prog_type(enum bpf_attach_type attach_type)
case BPF_CGROUP_INET_SOCK_RELEASE:
case BPF_CGROUP_INET4_POST_BIND:
case BPF_CGROUP_INET6_POST_BIND:
+ case BPF_CGROUP_TWSK_CLOSE:
return BPF_PROG_TYPE_CGROUP_SOCK;
case BPF_CGROUP_INET4_BIND:
case BPF_CGROUP_INET6_BIND:
@@ -3311,6 +3313,7 @@ static int bpf_prog_query(const union bpf_attr *attr,
case BPF_CGROUP_SYSCTL:
case BPF_CGROUP_GETSOCKOPT:
case BPF_CGROUP_SETSOCKOPT:
+ case BPF_CGROUP_TWSK_CLOSE:
return cgroup_bpf_prog_query(attr, uattr);
case BPF_LIRC_MODE2:
return lirc_prog_query(attr, uattr);
diff --git a/net/core/filter.c b/net/core/filter.c
index e4cc3aff5bf7..4d3847053a78 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -7927,6 +7927,7 @@ static bool __sock_filter_check_attach_type(int off,
case bpf_ctx_range(struct bpf_sock, src_ip4):
switch (attach_type) {
case BPF_CGROUP_INET4_POST_BIND:
+ case BPF_CGROUP_TWSK_CLOSE:
goto read_only;
default:
return false;
@@ -7934,6 +7935,7 @@ static bool __sock_filter_check_attach_type(int off,
case bpf_ctx_range_till(struct bpf_sock, src_ip6[0], src_ip6[3]):
switch (attach_type) {
case BPF_CGROUP_INET6_POST_BIND:
+ case BPF_CGROUP_TWSK_CLOSE:
goto read_only;
default:
return false;
@@ -7942,10 +7944,19 @@ static bool __sock_filter_check_attach_type(int off,
switch (attach_type) {
case BPF_CGROUP_INET4_POST_BIND:
case BPF_CGROUP_INET6_POST_BIND:
+ case BPF_CGROUP_TWSK_CLOSE:
goto read_only;
default:
return false;
}
+ case bpf_ctx_range(struct bpf_sock, protocol):
+ case bpf_ctx_range(struct bpf_sock, type):
+ switch (attach_type) {
+ case BPF_CGROUP_TWSK_CLOSE:
+ return false;
+ default:
+ break;
+ }
}
read_only:
return access_type == BPF_READ;
diff --git a/net/ipv4/inet_timewait_sock.c b/net/ipv4/inet_timewait_sock.c
index 437afe392e66..1fc4c9190a79 100644
--- a/net/ipv4/inet_timewait_sock.c
+++ b/net/ipv4/inet_timewait_sock.c
@@ -47,6 +47,8 @@ static void inet_twsk_kill(struct inet_timewait_sock *tw)
spinlock_t *lock = inet_ehash_lockp(hashinfo, tw->tw_hash);
struct inet_bind_hashbucket *bhead;
+ BPF_CGROUP_RUN_PROG_TWSK_CLOSE((struct sock *)tw);
+
spin_lock(lock);
sk_nulls_del_node_init_rcu((struct sock *)tw);
spin_unlock(lock);
@@ -184,6 +186,7 @@ struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk,
tw->tw_ipv6only = 0;
tw->tw_transparent = inet->transparent;
tw->tw_prot = sk->sk_prot_creator;
+ tw->tw_cgrp_data = sk->sk_cgrp_data;
atomic64_set(&tw->tw_cookie, atomic64_read(&sk->sk_cookie));
twsk_net_set(tw, sock_net(sk));
timer_setup(&tw->tw_timer, tw_timer_handler, TIMER_PINNED);
@@ -195,6 +198,7 @@ struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk,
refcount_set(&tw->tw_refcnt, 0);
__module_get(tw->tw_prot->owner);
+
}
return tw;
diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index 7c2d3ac2363a..1fc88e12ba95 100644
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -310,6 +310,9 @@ void tcp_time_wait(struct sock *sk, int state, int timeo)
if (state == TCP_TIME_WAIT)
timeo = TCP_TIMEWAIT_LEN;
+ if (BPF_SOCK_OPS_TEST_FLAG(tcp_sk(sk), BPF_SOCK_OPS_TW_CLOSE_FLAG))
+ tcp_sk(sk)->bpf_sock_ops_cb_flags &= ~BPF_SOCK_OPS_STATE_CB_FLAG;
+
/* tw_timer is pinned, so we need to make sure BH are disabled
* in following section, otherwise timer handler could run before
* we complete the initialization.
--
2.30.2