bpf: sockmap sample program

This program binds a program to a cgroup and then matches hard
coded IP addresses and adds these to a sockmap.

This will receive messages from the backend and send them to
the client.

     client:X <---> frontend:10000 client:X <---> backend:10001

To keep things simple this is only designed for 1:1 connections
using hard coded values. A more complete example would allow many
backends and clients.

To run,

 # sockmap <cgroup2_dir>

Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 15 insertions, 3 deletions

diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index e5bbb09..7766015 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -211,20 +211,28 @@ int bpf_obj_get(const char *pathname)
 	return sys_bpf(BPF_OBJ_GET, &attr, sizeof(attr));
 }
 
-int bpf_prog_attach(int prog_fd, int target_fd, enum bpf_attach_type type,
-		    unsigned int flags)
+int __bpf_prog_attach(int prog_fd1, int prog_fd2, int target_fd,
+		      enum bpf_attach_type type,
+		      unsigned int flags)
 {
 	union bpf_attr attr;
 
 	bzero(&attr, sizeof(attr));
 	attr.target_fd	   = target_fd;
-	attr.attach_bpf_fd = prog_fd;
+	attr.attach_bpf_fd = prog_fd1;
+	attr.attach_bpf_fd2 = prog_fd2;
 	attr.attach_type   = type;
 	attr.attach_flags  = flags;
 
 	return sys_bpf(BPF_PROG_ATTACH, &attr, sizeof(attr));
 }
 
+int bpf_prog_attach(int prog_fd, int target_fd, enum bpf_attach_type type,
+		    unsigned int flags)
+{
+	return __bpf_prog_attach(prog_fd, 0, target_fd, type, flags);
+}
+
 int bpf_prog_detach(int target_fd, enum bpf_attach_type type)
 {
 	union bpf_attr attr;
diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
index 418c86e..eaee585 100644
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -50,6 +50,10 @@ int bpf_obj_pin(int fd, const char *pathname);
 int bpf_obj_get(const char *pathname);
 int bpf_prog_attach(int prog_fd, int attachable_fd, enum bpf_attach_type type,
 		    unsigned int flags);
+int __bpf_prog_attach(int prog1, int prog2,
+		      int attachable_fd,
+		      enum bpf_attach_type type,
+		      unsigned int flags);
 int bpf_prog_detach(int attachable_fd, enum bpf_attach_type type);
 int bpf_prog_test_run(int prog_fd, int repeat, void *data, __u32 size,
 		      void *data_out, __u32 *size_out, __u32 *retval,