On 4/12/24 9:52 AM, Jordan Rife wrote:
This patch adds a set of kfuncs to bpf_testmod that can be used to
manipulate a socket from kernel space.
Signed-off-by: Jordan Rife <jrife@xxxxxxxxxx>
---
.../selftests/bpf/bpf_testmod/bpf_testmod.c | 139 ++++++++++++++++++
.../bpf/bpf_testmod/bpf_testmod_kfunc.h | 27 ++++
2 files changed, 166 insertions(+)
diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
index 39ad96a18123f..663df8148097e 100644
--- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
+++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
@@ -10,18 +10,29 @@
#include <linux/percpu-defs.h>
#include <linux/sysfs.h>
#include <linux/tracepoint.h>
+#include <linux/net.h>
+#include <linux/socket.h>
+#include <linux/nsproxy.h>
+#include <linux/inet.h>
+#include <linux/in.h>
+#include <linux/in6.h>
+#include <linux/un.h>
+#include <net/sock.h>
#include "bpf_testmod.h"
#include "bpf_testmod_kfunc.h"
#define CREATE_TRACE_POINTS
#include "bpf_testmod-events.h"
+#define CONNECT_TIMEOUT_SEC 1
+
typedef int (*func_proto_typedef)(long);
typedef int (*func_proto_typedef_nested1)(func_proto_typedef);
typedef int (*func_proto_typedef_nested2)(func_proto_typedef_nested1);
DEFINE_PER_CPU(int, bpf_testmod_ksym_percpu) = 123;
long bpf_testmod_test_struct_arg_result;
+static struct socket *sock;
struct bpf_testmod_struct_arg_1 {
int a;
@@ -494,6 +505,124 @@ __bpf_kfunc static u32 bpf_kfunc_call_test_static_unused_arg(u32 arg, u32 unused
return arg;
}
+__bpf_kfunc int bpf_kfunc_init_sock(struct init_sock_args *args)
+{
+ int proto;
+
+ if (sock)
+ pr_warn("%s called without releasing old sock", __func__);
hmm...this global sock pointer is quite unease. e.g. what if multiple tasks
trying to use init/close/connect... in parallel.
Storing sock in a bpf map will be better but that may be overkill for testing.
Can a separate global lock/mutex (not the lock_sock) be acquired first before
using the sock pointer in the kfuncs?
+
+ switch (args->af) {
+ case AF_INET:
+ case AF_INET6:
+ proto = args->type == SOCK_STREAM ? IPPROTO_TCP : IPPROTO_UDP;
+ break;
+ case AF_UNIX:
+ proto = PF_UNIX;
+ break;
+ default:
+ pr_err("invalid address family %d\n", args->af);
+ return -EINVAL;
+ }
+
+ return sock_create_kern(&init_net, args->af, args->type, proto, &sock);
+}
+
+__bpf_kfunc void bpf_kfunc_close_sock(void)
+{
+ if (sock) {
+ sock_release(sock);
bpf_testmod_exit() should probably do this NULL check and sock_release() also.
+ sock = NULL;
+ }
+}
+
+__bpf_kfunc int bpf_kfunc_call_kernel_connect(struct addr_args *args)
+{
+ /* Set timeout for call to kernel_connect() to prevent it from hanging,
+ * and consider the connection attempt failed if it returns
+ * -EINPROGRESS.
+ */
+ sock->sk->sk_sndtimeo = CONNECT_TIMEOUT_SEC * HZ;
Is it better to set sk_sndtimeo in bpf_kfunc_init_sock() ?
+
+ return kernel_connect(sock, (struct sockaddr *)&args->addr,
+ args->addrlen, 0);
+}
+
+__bpf_kfunc int bpf_kfunc_call_kernel_bind(struct addr_args *args)
+{
+ return kernel_bind(sock, (struct sockaddr *)&args->addr, args->addrlen);
+}
+
+__bpf_kfunc int bpf_kfunc_call_kernel_listen(void)
+{
+ return kernel_listen(sock, 128);
+}
+
+__bpf_kfunc int bpf_kfunc_call_kernel_sendmsg(struct sendmsg_args *args)
+{
+ struct msghdr msg = {
+ .msg_name = &args->addr.addr,
+ .msg_namelen = args->addr.addrlen,
+ };
+ struct kvec iov;
+ int err;
+
+ iov.iov_base = args->msg;
+ iov.iov_len = args->msglen;
+
+ err = kernel_sendmsg(sock, &msg, &iov, 1, args->msglen);
+ args->addr.addrlen = msg.msg_namelen;
+
+ return err;
+}
+
+__bpf_kfunc int bpf_kfunc_call_sock_sendmsg(struct sendmsg_args *args)
+{
+ struct msghdr msg = {
+ .msg_name = &args->addr.addr,
+ .msg_namelen = args->addr.addrlen,
+ };
+ struct kvec iov;
+ int err;
+
+ iov.iov_base = args->msg;
+ iov.iov_len = args->msglen;
+
+ iov_iter_kvec(&msg.msg_iter, ITER_SOURCE, &iov, 1, args->msglen);
+ err = sock_sendmsg(sock, &msg);
+ args->addr.addrlen = msg.msg_namelen;
+
+ return err;
+}
+
+__bpf_kfunc int bpf_kfunc_call_kernel_getsockname(struct addr_args *args)
+{
+ int err;
+
+ err = kernel_getsockname(sock, (struct sockaddr *)&args->addr);
+ if (err < 0)
+ goto out;
+
+ args->addrlen = err;
+ err = 0;
+out:
+ return err;
+}
+
+__bpf_kfunc int bpf_kfunc_call_kernel_getpeername(struct addr_args *args)
+{
+ int err;
+
+ err = kernel_getpeername(sock, (struct sockaddr *)&args->addr);
+ if (err < 0)
+ goto out;
+
+ args->addrlen = err;
+ err = 0;
+out:
+ return err;
+}
+
BTF_KFUNCS_START(bpf_testmod_check_kfunc_ids)
BTF_ID_FLAGS(func, bpf_testmod_test_mod_kfunc)
BTF_ID_FLAGS(func, bpf_kfunc_call_test1)
@@ -520,6 +649,15 @@ BTF_ID_FLAGS(func, bpf_kfunc_call_test_ref, KF_TRUSTED_ARGS | KF_RCU)
BTF_ID_FLAGS(func, bpf_kfunc_call_test_destructive, KF_DESTRUCTIVE)
BTF_ID_FLAGS(func, bpf_kfunc_call_test_static_unused_arg)
BTF_ID_FLAGS(func, bpf_kfunc_call_test_offset)
+BTF_ID_FLAGS(func, bpf_kfunc_init_sock)
+BTF_ID_FLAGS(func, bpf_kfunc_close_sock)
+BTF_ID_FLAGS(func, bpf_kfunc_call_kernel_connect)
+BTF_ID_FLAGS(func, bpf_kfunc_call_kernel_bind)
+BTF_ID_FLAGS(func, bpf_kfunc_call_kernel_listen)
+BTF_ID_FLAGS(func, bpf_kfunc_call_kernel_sendmsg)
+BTF_ID_FLAGS(func, bpf_kfunc_call_sock_sendmsg)
+BTF_ID_FLAGS(func, bpf_kfunc_call_kernel_getsockname)
+BTF_ID_FLAGS(func, bpf_kfunc_call_kernel_getpeername)
All these new kfunc should have the KF_SLEEPABLE flag.
BTF_KFUNCS_END(bpf_testmod_check_kfunc_ids)
static int bpf_testmod_ops_init(struct btf *btf)
@@ -650,6 +788,7 @@ static int bpf_testmod_init(void)
return ret;
if (bpf_fentry_test1(0) < 0)
return -EINVAL;
+ sock = NULL;
return sysfs_create_bin_file(kernel_kobj, &bin_attr_bpf_testmod_file);
}
diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h
index 7c664dd610597..cdf7769a7d8ca 100644
--- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h
+++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h
@@ -64,6 +64,22 @@ struct prog_test_fail3 {
char arr2[];
};
+struct init_sock_args {
+ int af;
+ int type;
+};
+
+struct addr_args {
+ char addr[sizeof(struct __kernel_sockaddr_storage)];
nit. Can "struct sockaddr_storage addr;" be directly used instead of a char array?
+ int addrlen;
+};
+
+struct sendmsg_args {
+ struct addr_args addr;
+ char msg[10];
+ int msglen;
+};
+
struct prog_test_ref_kfunc *
bpf_kfunc_call_test_acquire(unsigned long *scalar_ptr) __ksym;
void bpf_kfunc_call_test_release(struct prog_test_ref_kfunc *p) __ksym;
@@ -106,4 +122,15 @@ void bpf_kfunc_call_test_fail3(struct prog_test_fail3 *p);
void bpf_kfunc_call_test_mem_len_fail1(void *mem, int len);
void bpf_kfunc_common_test(void) __ksym;
+
+int bpf_kfunc_init_sock(struct init_sock_args *args) __ksym;
+void bpf_kfunc_close_sock(void) __ksym;
+int bpf_kfunc_call_kernel_connect(struct addr_args *args) __ksym;
+int bpf_kfunc_call_kernel_bind(struct addr_args *args) __ksym;
+int bpf_kfunc_call_kernel_listen(void) __ksym;
+int bpf_kfunc_call_kernel_sendmsg(struct sendmsg_args *args) __ksym;
+int bpf_kfunc_call_sock_sendmsg(struct sendmsg_args *args) __ksym;
+int bpf_kfunc_call_kernel_getsockname(struct addr_args *args) __ksym;
+int bpf_kfunc_call_kernel_getpeername(struct addr_args *args) __ksym;
+
#endif /* _BPF_TESTMOD_KFUNC_H */
