samples/bpf: Add detach option to test_cgrp2_sock

Add option to detach programs from a cgroup.

Signed-off-by: David Ahern <dsahern@gmail.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/samples/bpf/test_cgrp2_sock.c b/samples/bpf/test_cgrp2_sock.c
index 681abbe..1539676 100644 (file)
--- a/samples/bpf/test_cgrp2_sock.c
+++ b/samples/bpf/test_cgrp2_sock.c
@@ -114,7 +114,12 @@ static int prog_load(__u32 idx, __u32 mark, __u32 prio)
 
 static int usage(const char *argv0)
 {
-       printf("Usage: %s -b bind-to-dev -m mark -p prio cg-path\n", argv0);
+       printf("Usage:\n");
+       printf("  Attach a program\n");
+       printf("  %s -b bind-to-dev -m mark -p prio cg-path\n", argv0);
+       printf("\n");
+       printf("  Detach a program\n");
+       printf("  %s -d cg-path\n", argv0);
        return EXIT_FAILURE;
 }
 
@@ -123,10 +128,14 @@ int main(int argc, char **argv)
        __u32 idx = 0, mark = 0, prio = 0;
        const char *cgrp_path = NULL;
        int cg_fd, prog_fd, ret;
+       int do_attach = 1;
        int rc;
 
-       while ((rc = getopt(argc, argv, "b:m:p:")) != -1) {
+       while ((rc = getopt(argc, argv, "db:m:p:")) != -1) {
                switch (rc) {
+               case 'd':
+                       do_attach = 0;
+                       break;
                case 'b':
                        idx = if_nametoindex(optarg);
                        if (!idx) {
@@ -157,7 +166,7 @@ int main(int argc, char **argv)
                return EXIT_FAILURE;
        }
 
-       if (!idx && !mark && !prio) {
+       if (do_attach && !idx && !mark && !prio) {
                fprintf(stderr,
                        "One of device, mark or priority must be given\n");
                return EXIT_FAILURE;
@@ -169,20 +178,31 @@ int main(int argc, char **argv)
                return EXIT_FAILURE;
        }
 
-       prog_fd = prog_load(idx, mark, prio);
-       if (prog_fd < 0) {
-               printf("Failed to load prog: '%s'\n", strerror(errno));
-               printf("Output from kernel verifier:\n%s\n-------\n",
-                      bpf_log_buf);
-               return EXIT_FAILURE;
-       }
+       if (do_attach) {
+               prog_fd = prog_load(idx, mark, prio);
+               if (prog_fd < 0) {
+                       printf("Failed to load prog: '%s'\n", strerror(errno));
+                       printf("Output from kernel verifier:\n%s\n-------\n",
+                              bpf_log_buf);
+                       return EXIT_FAILURE;
+               }
 
-       ret = bpf_prog_attach(prog_fd, cg_fd, BPF_CGROUP_INET_SOCK_CREATE, 0);
-       if (ret < 0) {
-               printf("Failed to attach prog to cgroup: '%s'\n",
-                      strerror(errno));
-               return EXIT_FAILURE;
+               ret = bpf_prog_attach(prog_fd, cg_fd,
+                                     BPF_CGROUP_INET_SOCK_CREATE, 0);
+               if (ret < 0) {
+                       printf("Failed to attach prog to cgroup: '%s'\n",
+                              strerror(errno));
+                       return EXIT_FAILURE;
+               }
+       } else {
+               ret = bpf_prog_detach(cg_fd, BPF_CGROUP_INET_SOCK_CREATE);
+               if (ret < 0) {
+                       printf("Failed to detach prog from cgroup: '%s'\n",
+                              strerror(errno));
+                       return EXIT_FAILURE;
+               }
        }
 
+       close(cg_fd);
        return EXIT_SUCCESS;
 }