Currently, bpf_getsocktop and bpf_setsockopt helpers operate on the
'struct bpf_sock_ops' context in BPF_PROG_TYPE_CGROUP_SOCKOPT program.
Let's generalize them and make the first argument be 'struct bpf_sock'.
That way, in the future, we can allow those helpers in more places.
BPF_PROG_TYPE_CGROUP_SOCKOPT still has the existing helpers that operate
on 'struct bpf_sock_ops', but we add new bpf_{g,s}etsockopt that work
on 'struct bpf_sock'. [Alternatively, for BPF_PROG_TYPE_CGROUP_SOCKOPT,
we can enable them both and teach verifier to pick the right one
based on the context (bpf_sock_ops vs bpf_sock).]
As an example, let's allow those 'struct bpf_sock' based helpers to
be called from the BPF_CGROUP_INET{4,6}_CONNECT hooks. That way
we can override CC before the connection is made.
Signed-off-by: Stanislav Fomichev <sdf@xxxxxxxxxx>
---
include/uapi/linux/bpf.h | 12 +-
net/core/filter.c | 113 ++++++++++++++----
tools/include/uapi/linux/bpf.h | 12 +-
tools/testing/selftests/bpf/config | 1 +
.../selftests/bpf/progs/connect4_prog.c | 46 +++++++
5 files changed, 159 insertions(+), 25 deletions(-)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 4a6c47f3febe..68900c32d05f 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -1564,7 +1564,7 @@ union bpf_attr {
* Return
* 0
*
- * int bpf_setsockopt(struct bpf_sock_ops *bpf_socket, int level, int optname, void *optval, int optlen)
+ * int bpf_setsockopt(void *bpf_socket, int level, int optname, void *optval, int optlen)
* Description
* Emulate a call to **setsockopt()** on the socket associated to
* *bpf_socket*, which must be a full socket. The *level* at
@@ -1572,6 +1572,10 @@ union bpf_attr {
* must be specified, see **setsockopt(2)** for more information.
* The option value of length *optlen* is pointed by *optval*.
*
+ * *bpf_socket* should be one of the following:
+ * * **struct bpf_sock_ops** for **BPF_PROG_TYPE_CGROUP_SOCKOPT**.
+ * * **struct bpf_sock** for the other types.
+ *
* This helper actually implements a subset of **setsockopt()**.
* It supports the following *level*\ s:
*
@@ -1766,7 +1770,7 @@ union bpf_attr {
* Return
* 0 on success, or a negative error in case of failure.
*
- * int bpf_getsockopt(struct bpf_sock_ops *bpf_socket, int level, int optname, void *optval, int optlen)
+ * int bpf_getsockopt(void *bpf_socket, int level, int optname, void *optval, int optlen)
* Description
* Emulate a call to **getsockopt()** on the socket associated to
* *bpf_socket*, which must be a full socket. The *level* at
@@ -1775,6 +1779,10 @@ union bpf_attr {
* The retrieved value is stored in the structure pointed by
* *opval* and of length *optlen*.
*
+ * *bpf_socket* should be one of the following:
+ * * **struct bpf_sock_ops** for **BPF_PROG_TYPE_CGROUP_SOCKOPT**.
+ * * **struct bpf_sock** for the other types.
+ *
* This helper actually implements a subset of **getsockopt()**.
* It supports the following *level*\ s:
*
diff --git a/net/core/filter.c b/net/core/filter.c
index da3b7a72c37c..0e8f2c9cfe27 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -4194,16 +4194,19 @@ static const struct bpf_func_proto bpf_get_socket_uid_proto = {
.arg1_type = ARG_PTR_TO_CTX,
};
-BPF_CALL_5(bpf_setsockopt, struct bpf_sock_ops_kern *, bpf_sock,
- int, level, int, optname, char *, optval, int, optlen)
+#define SOCKOPT_CC_REINIT (1 << 0)
+
+static int _bpf_setsockopt(struct sock *sk, int level, int optname,
+ char *optval, int optlen, u32 flags)
{
- struct sock *sk = bpf_sock->sk;
int ret = 0;
int val;
if (!sk_fullsock(sk))
return -EINVAL;
+ sock_owned_by_me(sk);
+
if (level == SOL_SOCKET) {
if (optlen != sizeof(int))
return -EINVAL;
@@ -4298,7 +4301,7 @@ BPF_CALL_5(bpf_setsockopt, struct bpf_sock_ops_kern *, bpf_sock,
sk->sk_prot->setsockopt == tcp_setsockopt) {
if (optname == TCP_CONGESTION) {
char name[TCP_CA_NAME_MAX];
- bool reinit = bpf_sock->op > BPF_SOCK_OPS_NEEDS_ECN;
+ bool reinit = flags & SOCKOPT_CC_REINIT;
strncpy(name, optval, min_t(long, optlen,
TCP_CA_NAME_MAX-1));
@@ -4345,24 +4348,14 @@ BPF_CALL_5(bpf_setsockopt, struct bpf_sock_ops_kern *, bpf_sock,
return ret;
}
-static const struct bpf_func_proto bpf_setsockopt_proto = {
- .func = bpf_setsockopt,
- .gpl_only = false,
- .ret_type = RET_INTEGER,
- .arg1_type = ARG_PTR_TO_CTX,
- .arg2_type = ARG_ANYTHING,
- .arg3_type = ARG_ANYTHING,
- .arg4_type = ARG_PTR_TO_MEM,
- .arg5_type = ARG_CONST_SIZE,
-};
-
-BPF_CALL_5(bpf_getsockopt, struct bpf_sock_ops_kern *, bpf_sock,
- int, level, int, optname, char *, optval, int, optlen)
+static int _bpf_getsockopt(struct sock *sk, int level, int optname,
+ char *optval, int optlen)
{
- struct sock *sk = bpf_sock->sk;
-
if (!sk_fullsock(sk))
goto err_clear;
+
+ sock_owned_by_me(sk);
+
#ifdef CONFIG_INET
if (level == SOL_TCP && sk->sk_prot->getsockopt == tcp_getsockopt) {
struct inet_connection_sock *icsk;
@@ -4428,10 +4421,72 @@ BPF_CALL_5(bpf_getsockopt, struct bpf_sock_ops_kern *, bpf_sock,
return -EINVAL;
}
+BPF_CALL_5(bpf_setsockopt, struct sock *, sk,
+ int, level, int, optname, char *, optval, int, optlen)
+{
+ u32 flags = 0;
+ return _bpf_setsockopt(sk, level, optname, optval, optlen, flags);
+}
+
+static const struct bpf_func_proto bpf_setsockopt_proto = {
+ .func = bpf_setsockopt,
+ .gpl_only = false,
+ .ret_type = RET_INTEGER,
+ .arg1_type = ARG_PTR_TO_SOCKET,
+ .arg2_type = ARG_ANYTHING,
+ .arg3_type = ARG_ANYTHING,
+ .arg4_type = ARG_PTR_TO_MEM,
+ .arg5_type = ARG_CONST_SIZE,
+};
+
+BPF_CALL_5(bpf_getsockopt, struct sock *, sk,
+ int, level, int, optname, char *, optval, int, optlen)
+{
+ return _bpf_getsockopt(sk, level, optname, optval, optlen);
+}
+
static const struct bpf_func_proto bpf_getsockopt_proto = {
.func = bpf_getsockopt,
.gpl_only = false,
.ret_type = RET_INTEGER,
+ .arg1_type = ARG_PTR_TO_SOCKET,
+ .arg2_type = ARG_ANYTHING,
+ .arg3_type = ARG_ANYTHING,
+ .arg4_type = ARG_PTR_TO_UNINIT_MEM,
+ .arg5_type = ARG_CONST_SIZE,
+};
+
+BPF_CALL_5(bpf_sock_ops_setsockopt, struct bpf_sock_ops_kern *, bpf_sock,
+ int, level, int, optname, char *, optval, int, optlen)
+{
+ u32 flags = 0;
+ if (bpf_sock->op > BPF_SOCK_OPS_NEEDS_ECN)
+ flags |= SOCKOPT_CC_REINIT;
+ return _bpf_setsockopt(bpf_sock->sk, level, optname, optval, optlen,
+ flags);
+}
+
+static const struct bpf_func_proto bpf_sock_ops_setsockopt_proto = {
+ .func = bpf_sock_ops_setsockopt,
+ .gpl_only = false,
+ .ret_type = RET_INTEGER,
+ .arg1_type = ARG_PTR_TO_CTX,
+ .arg2_type = ARG_ANYTHING,
+ .arg3_type = ARG_ANYTHING,
+ .arg4_type = ARG_PTR_TO_MEM,
+ .arg5_type = ARG_CONST_SIZE,
+};
+
+BPF_CALL_5(bpf_sock_ops_getsockopt, struct bpf_sock_ops_kern *, bpf_sock,
+ int, level, int, optname, char *, optval, int, optlen)
+{
+ return _bpf_getsockopt(bpf_sock->sk, level, optname, optval, optlen);
+}
+
+static const struct bpf_func_proto bpf_sock_ops_getsockopt_proto = {
+ .func = bpf_sock_ops_getsockopt,
+ .gpl_only = false,
+ .ret_type = RET_INTEGER,
.arg1_type = ARG_PTR_TO_CTX,
.arg2_type = ARG_ANYTHING,
.arg3_type = ARG_ANYTHING,
@@ -6043,6 +6098,22 @@ sock_addr_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
return &bpf_sk_storage_get_proto;
case BPF_FUNC_sk_storage_delete:
return &bpf_sk_storage_delete_proto;
+ case BPF_FUNC_setsockopt:
+ switch (prog->expected_attach_type) {
+ case BPF_CGROUP_INET4_CONNECT:
+ case BPF_CGROUP_INET6_CONNECT:
+ return &bpf_setsockopt_proto;
+ default:
+ return NULL;
+ }
+ case BPF_FUNC_getsockopt:
+ switch (prog->expected_attach_type) {
+ case BPF_CGROUP_INET4_CONNECT:
+ case BPF_CGROUP_INET6_CONNECT:
+ return &bpf_getsockopt_proto;
+ default:
+ return NULL;
+ }
default:
return bpf_base_func_proto(func_id);
}
@@ -6261,9 +6332,9 @@ sock_ops_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
{
switch (func_id) {
case BPF_FUNC_setsockopt:
- return &bpf_setsockopt_proto;
+ return &bpf_sock_ops_setsockopt_proto;
case BPF_FUNC_getsockopt:
- return &bpf_getsockopt_proto;
+ return &bpf_sock_ops_getsockopt_proto;
case BPF_FUNC_sock_ops_cb_flags_set:
return &bpf_sock_ops_cb_flags_set_proto;
case BPF_FUNC_sock_map_update:
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 4a6c47f3febe..68900c32d05f 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -1564,7 +1564,7 @@ union bpf_attr {
* Return
* 0
*
- * int bpf_setsockopt(struct bpf_sock_ops *bpf_socket, int level, int optname, void *optval, int optlen)
+ * int bpf_setsockopt(void *bpf_socket, int level, int optname, void *optval, int optlen)
* Description
* Emulate a call to **setsockopt()** on the socket associated to
* *bpf_socket*, which must be a full socket. The *level* at
@@ -1572,6 +1572,10 @@ union bpf_attr {
* must be specified, see **setsockopt(2)** for more information.
* The option value of length *optlen* is pointed by *optval*.
*
+ * *bpf_socket* should be one of the following:
+ * * **struct bpf_sock_ops** for **BPF_PROG_TYPE_CGROUP_SOCKOPT**.
+ * * **struct bpf_sock** for the other types.
+ *
* This helper actually implements a subset of **setsockopt()**.
* It supports the following *level*\ s:
*
@@ -1766,7 +1770,7 @@ union bpf_attr {
* Return
* 0 on success, or a negative error in case of failure.
*
- * int bpf_getsockopt(struct bpf_sock_ops *bpf_socket, int level, int optname, void *optval, int optlen)
+ * int bpf_getsockopt(void *bpf_socket, int level, int optname, void *optval, int optlen)
* Description
* Emulate a call to **getsockopt()** on the socket associated to
* *bpf_socket*, which must be a full socket. The *level* at
@@ -1775,6 +1779,10 @@ union bpf_attr {
* The retrieved value is stored in the structure pointed by
* *opval* and of length *optlen*.
*
+ * *bpf_socket* should be one of the following:
+ * * **struct bpf_sock_ops** for **BPF_PROG_TYPE_CGROUP_SOCKOPT**.
+ * * **struct bpf_sock** for the other types.
+ *
* This helper actually implements a subset of **getsockopt()**.
* It supports the following *level*\ s:
*
diff --git a/tools/testing/selftests/bpf/config b/tools/testing/selftests/bpf/config
index 60e3ae5d4e48..6e5b94c036ca 100644
--- a/tools/testing/selftests/bpf/config
+++ b/tools/testing/selftests/bpf/config
@@ -37,3 +37,4 @@ CONFIG_IPV6_SIT=m
CONFIG_BPF_JIT=y
CONFIG_BPF_LSM=y
CONFIG_SECURITY=y
+CONFIG_TCP_CONG_DCTCP=y
diff --git a/tools/testing/selftests/bpf/progs/connect4_prog.c b/tools/testing/selftests/bpf/progs/connect4_prog.c
index ad3c498a8150..656eb8c1ffc8 100644
--- a/tools/testing/selftests/bpf/progs/connect4_prog.c
+++ b/tools/testing/selftests/bpf/progs/connect4_prog.c
@@ -8,6 +8,7 @@
#include <linux/in.h>
#include <linux/in6.h>
#include <sys/socket.h>
+#include <netinet/tcp.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_endian.h>
@@ -16,6 +17,10 @@
#define DST_REWRITE_IP4 0x7f000001U
#define DST_REWRITE_PORT4 4444
+#ifndef TCP_CA_NAME_MAX
+#define TCP_CA_NAME_MAX 16
+#endif
+
int _version SEC("version") = 1;
__attribute__ ((noinline))
@@ -33,6 +38,43 @@ int do_bind(struct bpf_sock_addr *ctx)
return 1;
}
+static __inline int verify_cc(struct bpf_sock *sk,
+ char expected[TCP_CA_NAME_MAX])
+{
+ char buf[TCP_CA_NAME_MAX];
+ int i;
+
+ if (bpf_getsockopt(sk, SOL_TCP, TCP_CONGESTION, &buf, sizeof(buf)))
+ return 1;
+
+ for (i = 0; i < TCP_CA_NAME_MAX; i++) {
+ if (buf[i] != expected[i])
+ return 1;
+ if (buf[i] == 0)
+ break;
+ }
+
+ return 0;
+}
+
+static __inline int set_cc(struct bpf_sock *sk)
+{
+ char dctcp[TCP_CA_NAME_MAX] = "dctcp";
+ char cubic[TCP_CA_NAME_MAX] = "cubic";
+
+ if (bpf_setsockopt(sk, SOL_TCP, TCP_CONGESTION, &dctcp, sizeof(dctcp)))
+ return 1;
+ if (verify_cc(sk, dctcp))
+ return 1;
+
+ if (bpf_setsockopt(sk, SOL_TCP, TCP_CONGESTION, &cubic, sizeof(cubic)))
+ return 1;
+ if (verify_cc(sk, cubic))
+ return 1;
+
+ return 0;
+}
+
SEC("cgroup/connect4")
int connect_v4_prog(struct bpf_sock_addr *ctx)
{
@@ -66,6 +108,10 @@ int connect_v4_prog(struct bpf_sock_addr *ctx)
bpf_sk_release(sk);
+ /* Rewrite congestion control. */
+ if (ctx->type == SOCK_STREAM && set_cc(ctx->sk))
+ return 0;
+
/* Rewrite destination. */
ctx->user_ip4 = bpf_htonl(DST_REWRITE_IP4);
ctx->user_port = bpf_htons(DST_REWRITE_PORT4);
--
2.26.2.303.gf8c07b1a785-goog
