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bpf: add skc_lookup_tcp helper 

Allow looking up a sock_common. This gives eBPF programs
access to timewait and request sockets.

Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Lorenz Bauer 2019-03-22 09:54:01 +08:00 committed by Alexei Starovoitov
parent 85a51f8c28
commit edbf8c01de
3 changed files with 144 additions and 25 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
include/uapi/linux/bpf.h
View File

@ -2431,6 +2431,23 @@ union bpf_attr {
* Return
* A **struct bpf_sock** pointer on success, or **NULL** in
* case of failure.
*
* struct bpf_sock *bpf_skc_lookup_tcp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
* Description
* Look for TCP socket matching *tuple*, optionally in a child
* network namespace *netns*. The return value must be checked,
* and if non-**NULL**, released via **bpf_sk_release**\ ().
*
* This function is identical to bpf_sk_lookup_tcp, except that it
* also returns timewait or request sockets. Use bpf_sk_fullsock
* or bpf_tcp_socket to access the full structure.
*
* This helper is available only if the kernel was compiled with
* **CONFIG_NET** configuration option.
* Return
* Pointer to **struct bpf_sock**, or **NULL** in case of failure.
* For sockets with reuseport option, the **struct bpf_sock**
* result is from **reuse->socks**\ [] using the hash of the tuple.
*/
#define __BPF_FUNC_MAPPER(FN) \
FN(unspec), \
@ -2531,7 +2548,8 @@ union bpf_attr {
FN(sk_fullsock), \
FN(tcp_sock), \
FN(skb_ecn_set_ce), \
FN(get_listener_sock),
FN(get_listener_sock), \
FN(skc_lookup_tcp),
/* integer value in 'imm' field of BPF_CALL instruction selects which helper
* function eBPF program intends to call

3
kernel/bpf/verifier.c
View File

@ -369,7 +369,8 @@ static bool is_release_function(enum bpf_func_id func_id)
static bool is_acquire_function(enum bpf_func_id func_id)
{
return func_id == BPF_FUNC_sk_lookup_tcp ||
func_id == BPF_FUNC_sk_lookup_udp;
func_id == BPF_FUNC_sk_lookup_udp ||
func_id == BPF_FUNC_skc_lookup_tcp;
}
static bool is_ptr_cast_function(enum bpf_func_id func_id)

146
net/core/filter.c
View File

@ -5156,15 +5156,15 @@ static struct sock *sk_lookup(struct net *net, struct bpf_sock_tuple *tuple,
return sk;
}
/* bpf_sk_lookup performs the core lookup for different types of sockets,
/* bpf_skc_lookup performs the core lookup for different types of sockets,
* taking a reference on the socket if it doesn't have the flag SOCK_RCU_FREE.
* Returns the socket as an 'unsigned long' to simplify the casting in the
* callers to satisfy BPF_CALL declarations.
*/
static unsigned long
__bpf_sk_lookup(struct sk_buff *skb, struct bpf_sock_tuple *tuple, u32 len,
struct net *caller_net, u32 ifindex, u8 proto, u64 netns_id,
u64 flags)
static struct sock *
__bpf_skc_lookup(struct sk_buff *skb, struct bpf_sock_tuple *tuple, u32 len,
struct net *caller_net, u32 ifindex, u8 proto, u64 netns_id,
u64 flags)
{
struct sock *sk = NULL;
u8 family = AF_UNSPEC;
@ -5192,15 +5192,27 @@ __bpf_sk_lookup(struct sk_buff *skb, struct bpf_sock_tuple *tuple, u32 len,
put_net(net);
}
if (sk)
sk = sk_to_full_sk(sk);
out:
return (unsigned long) sk;
return sk;
}
static unsigned long
bpf_sk_lookup(struct sk_buff *skb, struct bpf_sock_tuple *tuple, u32 len,
u8 proto, u64 netns_id, u64 flags)
static struct sock *
__bpf_sk_lookup(struct sk_buff *skb, struct bpf_sock_tuple *tuple, u32 len,
struct net *caller_net, u32 ifindex, u8 proto, u64 netns_id,
u64 flags)
{
struct sock *sk = __bpf_skc_lookup(skb, tuple, len, caller_net,
ifindex, proto, netns_id, flags);
if (sk)
sk = sk_to_full_sk(sk);
return sk;
}
static struct sock *
bpf_skc_lookup(struct sk_buff *skb, struct bpf_sock_tuple *tuple, u32 len,
u8 proto, u64 netns_id, u64 flags)
{
struct net *caller_net;
int ifindex;
@ -5213,14 +5225,47 @@ bpf_sk_lookup(struct sk_buff *skb, struct bpf_sock_tuple *tuple, u32 len,
ifindex = 0;
}
return __bpf_sk_lookup(skb, tuple, len, caller_net, ifindex,
proto, netns_id, flags);
return __bpf_skc_lookup(skb, tuple, len, caller_net, ifindex, proto,
netns_id, flags);
}
static struct sock *
bpf_sk_lookup(struct sk_buff *skb, struct bpf_sock_tuple *tuple, u32 len,
u8 proto, u64 netns_id, u64 flags)
{
struct sock *sk = bpf_skc_lookup(skb, tuple, len, proto, netns_id,
flags);
if (sk)
sk = sk_to_full_sk(sk);
return sk;
}
BPF_CALL_5(bpf_skc_lookup_tcp, struct sk_buff *, skb,
struct bpf_sock_tuple *, tuple, u32, len, u64, netns_id, u64, flags)
{
return (unsigned long)bpf_skc_lookup(skb, tuple, len, IPPROTO_TCP,
netns_id, flags);
}
static const struct bpf_func_proto bpf_skc_lookup_tcp_proto = {
.func = bpf_skc_lookup_tcp,
.gpl_only = false,
.pkt_access = true,
.ret_type = RET_PTR_TO_SOCK_COMMON_OR_NULL,
.arg1_type = ARG_PTR_TO_CTX,
.arg2_type = ARG_PTR_TO_MEM,
.arg3_type = ARG_CONST_SIZE,
.arg4_type = ARG_ANYTHING,
.arg5_type = ARG_ANYTHING,
};
BPF_CALL_5(bpf_sk_lookup_tcp, struct sk_buff *, skb,
struct bpf_sock_tuple *, tuple, u32, len, u64, netns_id, u64, flags)
{
return bpf_sk_lookup(skb, tuple, len, IPPROTO_TCP, netns_id, flags);
return (unsigned long)bpf_sk_lookup(skb, tuple, len, IPPROTO_TCP,
netns_id, flags);
}
static const struct bpf_func_proto bpf_sk_lookup_tcp_proto = {
@ -5238,7 +5283,8 @@ static const struct bpf_func_proto bpf_sk_lookup_tcp_proto = {
BPF_CALL_5(bpf_sk_lookup_udp, struct sk_buff *, skb,
struct bpf_sock_tuple *, tuple, u32, len, u64, netns_id, u64, flags)
{
return bpf_sk_lookup(skb, tuple, len, IPPROTO_UDP, netns_id, flags);
return (unsigned long)bpf_sk_lookup(skb, tuple, len, IPPROTO_UDP,
netns_id, flags);
}
static const struct bpf_func_proto bpf_sk_lookup_udp_proto = {
@ -5273,8 +5319,9 @@ BPF_CALL_5(bpf_xdp_sk_lookup_udp, struct xdp_buff *, ctx,
struct net *caller_net = dev_net(ctx->rxq->dev);
int ifindex = ctx->rxq->dev->ifindex;
return __bpf_sk_lookup(NULL, tuple, len, caller_net, ifindex,
IPPROTO_UDP, netns_id, flags);
return (unsigned long)__bpf_sk_lookup(NULL, tuple, len, caller_net,
ifindex, IPPROTO_UDP, netns_id,
flags);
}
static const struct bpf_func_proto bpf_xdp_sk_lookup_udp_proto = {
@ -5289,14 +5336,38 @@ static const struct bpf_func_proto bpf_xdp_sk_lookup_udp_proto = {
.arg5_type = ARG_ANYTHING,
};
BPF_CALL_5(bpf_xdp_skc_lookup_tcp, struct xdp_buff *, ctx,
struct bpf_sock_tuple *, tuple, u32, len, u32, netns_id, u64, flags)
{
struct net *caller_net = dev_net(ctx->rxq->dev);
int ifindex = ctx->rxq->dev->ifindex;
return (unsigned long)__bpf_skc_lookup(NULL, tuple, len, caller_net,
ifindex, IPPROTO_TCP, netns_id,
flags);
}
static const struct bpf_func_proto bpf_xdp_skc_lookup_tcp_proto = {
.func = bpf_xdp_skc_lookup_tcp,
.gpl_only = false,
.pkt_access = true,
.ret_type = RET_PTR_TO_SOCK_COMMON_OR_NULL,
.arg1_type = ARG_PTR_TO_CTX,
.arg2_type = ARG_PTR_TO_MEM,
.arg3_type = ARG_CONST_SIZE,
.arg4_type = ARG_ANYTHING,
.arg5_type = ARG_ANYTHING,
};
BPF_CALL_5(bpf_xdp_sk_lookup_tcp, struct xdp_buff *, ctx,
struct bpf_sock_tuple *, tuple, u32, len, u32, netns_id, u64, flags)
{
struct net *caller_net = dev_net(ctx->rxq->dev);
int ifindex = ctx->rxq->dev->ifindex;
return __bpf_sk_lookup(NULL, tuple, len, caller_net, ifindex,
IPPROTO_TCP, netns_id, flags);
return (unsigned long)__bpf_sk_lookup(NULL, tuple, len, caller_net,
ifindex, IPPROTO_TCP, netns_id,
flags);
}
static const struct bpf_func_proto bpf_xdp_sk_lookup_tcp_proto = {
@ -5311,11 +5382,31 @@ static const struct bpf_func_proto bpf_xdp_sk_lookup_tcp_proto = {
.arg5_type = ARG_ANYTHING,
};
BPF_CALL_5(bpf_sock_addr_skc_lookup_tcp, struct bpf_sock_addr_kern *, ctx,
struct bpf_sock_tuple *, tuple, u32, len, u64, netns_id, u64, flags)
{
return (unsigned long)__bpf_skc_lookup(NULL, tuple, len,
sock_net(ctx->sk), 0,
IPPROTO_TCP, netns_id, flags);
}
static const struct bpf_func_proto bpf_sock_addr_skc_lookup_tcp_proto = {
.func = bpf_sock_addr_skc_lookup_tcp,
.gpl_only = false,
.ret_type = RET_PTR_TO_SOCK_COMMON_OR_NULL,
.arg1_type = ARG_PTR_TO_CTX,
.arg2_type = ARG_PTR_TO_MEM,
.arg3_type = ARG_CONST_SIZE,
.arg4_type = ARG_ANYTHING,
.arg5_type = ARG_ANYTHING,
};
BPF_CALL_5(bpf_sock_addr_sk_lookup_tcp, struct bpf_sock_addr_kern *, ctx,
struct bpf_sock_tuple *, tuple, u32, len, u64, netns_id, u64, flags)
{
return __bpf_sk_lookup(NULL, tuple, len, sock_net(ctx->sk), 0,
IPPROTO_TCP, netns_id, flags);
return (unsigned long)__bpf_sk_lookup(NULL, tuple, len,
sock_net(ctx->sk), 0, IPPROTO_TCP,
netns_id, flags);
}
static const struct bpf_func_proto bpf_sock_addr_sk_lookup_tcp_proto = {
@ -5332,8 +5423,9 @@ static const struct bpf_func_proto bpf_sock_addr_sk_lookup_tcp_proto = {
BPF_CALL_5(bpf_sock_addr_sk_lookup_udp, struct bpf_sock_addr_kern *, ctx,
struct bpf_sock_tuple *, tuple, u32, len, u64, netns_id, u64, flags)
{
return __bpf_sk_lookup(NULL, tuple, len, sock_net(ctx->sk), 0,
IPPROTO_UDP, netns_id, flags);
return (unsigned long)__bpf_sk_lookup(NULL, tuple, len,
sock_net(ctx->sk), 0, IPPROTO_UDP,
netns_id, flags);
}
static const struct bpf_func_proto bpf_sock_addr_sk_lookup_udp_proto = {
@ -5586,6 +5678,8 @@ sock_addr_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
return &bpf_sock_addr_sk_lookup_udp_proto;
case BPF_FUNC_sk_release:
return &bpf_sk_release_proto;
case BPF_FUNC_skc_lookup_tcp:
return &bpf_sock_addr_skc_lookup_tcp_proto;
#endif /* CONFIG_INET */
default:
return bpf_base_func_proto(func_id);
@ -5719,6 +5813,8 @@ tc_cls_act_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
return &bpf_tcp_sock_proto;
case BPF_FUNC_get_listener_sock:
return &bpf_get_listener_sock_proto;
case BPF_FUNC_skc_lookup_tcp:
return &bpf_skc_lookup_tcp_proto;
#endif
default:
return bpf_base_func_proto(func_id);
@ -5754,6 +5850,8 @@ xdp_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
return &bpf_xdp_sk_lookup_tcp_proto;
case BPF_FUNC_sk_release:
return &bpf_sk_release_proto;
case BPF_FUNC_skc_lookup_tcp:
return &bpf_xdp_skc_lookup_tcp_proto;
#endif
default:
return bpf_base_func_proto(func_id);
@ -5846,6 +5944,8 @@ sk_skb_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
return &bpf_sk_lookup_udp_proto;
case BPF_FUNC_sk_release:
return &bpf_sk_release_proto;
case BPF_FUNC_skc_lookup_tcp:
return &bpf_skc_lookup_tcp_proto;
#endif
default:
return bpf_base_func_proto(func_id);