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sock: Introduce sk->sk_prot->psock_update_sk_prot()

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Currently sockmap calls into each protocol to update the struct
proto and replace it. This certainly won't work when the protocol
is implemented as a module, for example, AF_UNIX.

Introduce a new ops sk->sk_prot->psock_update_sk_prot(), so each
protocol can implement its own way to replace the struct proto.
This also helps get rid of symbol dependencies on CONFIG_INET.

Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210331023237.41094-11-xiyou.wangcong@gmail.com
This commit is contained in:
Cong Wang 2021-03-30 19:32:31 -07:00 committed by Alexei Starovoitov
parent a7ba4558e6
commit 8a59f9d1e3
12 changed files with 58 additions and 45 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

18
include/linux/skmsg.h
View file

@ -99,6 +99,7 @@ struct sk_psock {
void (*saved_close)(struct sock *sk, long timeout);
void (*saved_write_space)(struct sock *sk);
void (*saved_data_ready)(struct sock *sk);
int (*psock_update_sk_prot)(struct sock *sk, bool restore);
struct proto *sk_proto;
struct mutex work_mutex;
struct sk_psock_work_state work_state;
@ -395,25 +396,12 @@ static inline void sk_psock_cork_free(struct sk_psock *psock)
}
}
static inline void sk_psock_update_proto(struct sock *sk,
struct sk_psock *psock,
struct proto *ops)
{
/* Pairs with lockless read in sk_clone_lock() */
WRITE_ONCE(sk->sk_prot, ops);
}
static inline void sk_psock_restore_proto(struct sock *sk,
struct sk_psock *psock)
{
sk->sk_prot->unhash = psock->saved_unhash;
if (inet_csk_has_ulp(sk)) {
tcp_update_ulp(sk, psock->sk_proto, psock->saved_write_space);
} else {
sk->sk_write_space = psock->saved_write_space;
/* Pairs with lockless read in sk_clone_lock() */
WRITE_ONCE(sk->sk_prot, psock->sk_proto);
}
if (psock->psock_update_sk_prot)
psock->psock_update_sk_prot(sk, true);
}
static inline void sk_psock_set_state(struct sk_psock *psock,

3
include/net/sock.h
View file

@ -1184,6 +1184,9 @@ struct proto {
void (*unhash)(struct sock *sk);
void (*rehash)(struct sock *sk);
int (*get_port)(struct sock *sk, unsigned short snum);
#ifdef CONFIG_BPF_SYSCALL
int (*psock_update_sk_prot)(struct sock *sk, bool restore);
#endif
/* Keeping track of sockets in use */
#ifdef CONFIG_PROC_FS

1
include/net/tcp.h
View file

@ -2203,6 +2203,7 @@ struct sk_psock;
#ifdef CONFIG_BPF_SYSCALL
struct proto *tcp_bpf_get_proto(struct sock *sk, struct sk_psock *psock);
int tcp_bpf_update_proto(struct sock *sk, bool restore);
void tcp_bpf_clone(const struct sock *sk, struct sock *newsk);
#endif /* CONFIG_BPF_SYSCALL */

1
include/net/udp.h
View file

@ -518,6 +518,7 @@ static inline struct sk_buff *udp_rcv_segment(struct sock *sk,
#ifdef CONFIG_BPF_SYSCALL
struct sk_psock;
struct proto *udp_bpf_get_proto(struct sock *sk, struct sk_psock *psock);
int udp_bpf_update_proto(struct sock *sk, bool restore);
#endif
#endif /* _UDP_H */

5
net/core/skmsg.c
View file

@ -562,11 +562,6 @@ struct sk_psock *sk_psock_init(struct sock *sk, int node)
write_lock_bh(&sk->sk_callback_lock);
if (inet_csk_has_ulp(sk)) {
psock = ERR_PTR(-EINVAL);
goto out;
}
if (sk->sk_user_data) {
psock = ERR_PTR(-EBUSY);
goto out;

24
net/core/sock_map.c
View file

@ -185,26 +185,10 @@ static void sock_map_unref(struct sock *sk, void *link_raw)
static int sock_map_init_proto(struct sock *sk, struct sk_psock *psock)
{
struct proto *prot;
switch (sk->sk_type) {
case SOCK_STREAM:
prot = tcp_bpf_get_proto(sk, psock);
break;
case SOCK_DGRAM:
prot = udp_bpf_get_proto(sk, psock);
break;
default:
if (!sk->sk_prot->psock_update_sk_prot)
return -EINVAL;
}
if (IS_ERR(prot))
return PTR_ERR(prot);
sk_psock_update_proto(sk, psock, prot);
return 0;
psock->psock_update_sk_prot = sk->sk_prot->psock_update_sk_prot;
return sk->sk_prot->psock_update_sk_prot(sk, false);
}
static struct sk_psock *sock_map_psock_get_checked(struct sock *sk)
@ -556,7 +540,7 @@ static bool sock_map_redirect_allowed(const struct sock *sk)
static bool sock_map_sk_is_suitable(const struct sock *sk)
{
return sk_is_tcp(sk) || sk_is_udp(sk);
return !!sk->sk_prot->psock_update_sk_prot;
}
static bool sock_map_sk_state_allowed(const struct sock *sk)

24
net/ipv4/tcp_bpf.c
View file

@ -595,20 +595,38 @@ static int tcp_bpf_assert_proto_ops(struct proto *ops)
ops->sendpage == tcp_sendpage ? 0 : -ENOTSUPP;
}
struct proto *tcp_bpf_get_proto(struct sock *sk, struct sk_psock *psock)
int tcp_bpf_update_proto(struct sock *sk, bool restore)
{
struct sk_psock *psock = sk_psock(sk);
int family = sk->sk_family == AF_INET6 ? TCP_BPF_IPV6 : TCP_BPF_IPV4;
int config = psock->progs.msg_parser ? TCP_BPF_TX : TCP_BPF_BASE;
if (restore) {
if (inet_csk_has_ulp(sk)) {
tcp_update_ulp(sk, psock->sk_proto, psock->saved_write_space);
} else {
sk->sk_write_space = psock->saved_write_space;
/* Pairs with lockless read in sk_clone_lock() */
WRITE_ONCE(sk->sk_prot, psock->sk_proto);
}
return 0;
}
if (inet_csk_has_ulp(sk))
return -EINVAL;
if (sk->sk_family == AF_INET6) {
if (tcp_bpf_assert_proto_ops(psock->sk_proto))
return ERR_PTR(-EINVAL);
return -EINVAL;
tcp_bpf_check_v6_needs_rebuild(psock->sk_proto);
}
return &tcp_bpf_prots[family][config];
/* Pairs with lockless read in sk_clone_lock() */
WRITE_ONCE(sk->sk_prot, &tcp_bpf_prots[family][config]);
return 0;
}
EXPORT_SYMBOL_GPL(tcp_bpf_update_proto);
/* If a child got cloned from a listening socket that had tcp_bpf
* protocol callbacks installed, we need to restore the callbacks to

3
net/ipv4/tcp_ipv4.c
View file

@ -2806,6 +2806,9 @@ struct proto tcp_prot = {
.hash = inet_hash,
.unhash = inet_unhash,
.get_port = inet_csk_get_port,
#ifdef CONFIG_BPF_SYSCALL
.psock_update_sk_prot = tcp_bpf_update_proto,
#endif
.enter_memory_pressure = tcp_enter_memory_pressure,
.leave_memory_pressure = tcp_leave_memory_pressure,
.stream_memory_free = tcp_stream_memory_free,

3
net/ipv4/udp.c
View file

@ -2849,6 +2849,9 @@ struct proto udp_prot = {
.unhash = udp_lib_unhash,
.rehash = udp_v4_rehash,
.get_port = udp_v4_get_port,
#ifdef CONFIG_BPF_SYSCALL
.psock_update_sk_prot = udp_bpf_update_proto,
#endif
.memory_allocated = &udp_memory_allocated,
.sysctl_mem = sysctl_udp_mem,
.sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_udp_wmem_min),

15
net/ipv4/udp_bpf.c
View file

@ -41,12 +41,23 @@ static int __init udp_bpf_v4_build_proto(void)
}
core_initcall(udp_bpf_v4_build_proto);
struct proto *udp_bpf_get_proto(struct sock *sk, struct sk_psock *psock)
int udp_bpf_update_proto(struct sock *sk, bool restore)
{
int family = sk->sk_family == AF_INET ? UDP_BPF_IPV4 : UDP_BPF_IPV6;
struct sk_psock *psock = sk_psock(sk);
if (restore) {
sk->sk_write_space = psock->saved_write_space;
/* Pairs with lockless read in sk_clone_lock() */
WRITE_ONCE(sk->sk_prot, psock->sk_proto);
return 0;
}
if (sk->sk_family == AF_INET6)
udp_bpf_check_v6_needs_rebuild(psock->sk_proto);
return &udp_bpf_prots[family];
/* Pairs with lockless read in sk_clone_lock() */
WRITE_ONCE(sk->sk_prot, &udp_bpf_prots[family]);
return 0;
}
EXPORT_SYMBOL_GPL(udp_bpf_update_proto);

3
net/ipv6/tcp_ipv6.c
View file

@ -2139,6 +2139,9 @@ struct proto tcpv6_prot = {
.hash = inet6_hash,
.unhash = inet_unhash,
.get_port = inet_csk_get_port,
#ifdef CONFIG_BPF_SYSCALL
.psock_update_sk_prot = tcp_bpf_update_proto,
#endif
.enter_memory_pressure = tcp_enter_memory_pressure,
.leave_memory_pressure = tcp_leave_memory_pressure,
.stream_memory_free = tcp_stream_memory_free,

3
net/ipv6/udp.c
View file

@ -1713,6 +1713,9 @@ struct proto udpv6_prot = {
.unhash = udp_lib_unhash,
.rehash = udp_v6_rehash,
.get_port = udp_v6_get_port,
#ifdef CONFIG_BPF_SYSCALL
.psock_update_sk_prot = udp_bpf_update_proto,
#endif
.memory_allocated = &udp_memory_allocated,
.sysctl_mem = sysctl_udp_mem,
.sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_udp_wmem_min),