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

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
Show 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),