xref: /openbmc/linux/include/net/scm.h (revision d5cb9783536a41df9f9cba5b0a1d78047ed787f7)
1 #ifndef __LINUX_NET_SCM_H
2 #define __LINUX_NET_SCM_H
3 
4 #include <linux/limits.h>
5 #include <linux/net.h>
6 
7 /* Well, we should have at least one descriptor open
8  * to accept passed FDs 8)
9  */
10 #define SCM_MAX_FD	(OPEN_MAX-1)
11 
12 struct scm_fp_list
13 {
14 	int		count;
15 	struct file	*fp[SCM_MAX_FD];
16 };
17 
18 struct scm_cookie
19 {
20 	struct ucred		creds;		/* Skb credentials	*/
21 	struct scm_fp_list	*fp;		/* Passed files		*/
22 	unsigned long		seq;		/* Connection seqno	*/
23 };
24 
25 extern void scm_detach_fds(struct msghdr *msg, struct scm_cookie *scm);
26 extern void scm_detach_fds_compat(struct msghdr *msg, struct scm_cookie *scm);
27 extern int __scm_send(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm);
28 extern void __scm_destroy(struct scm_cookie *scm);
29 extern struct scm_fp_list * scm_fp_dup(struct scm_fp_list *fpl);
30 
31 static __inline__ void scm_destroy(struct scm_cookie *scm)
32 {
33 	if (scm && scm->fp)
34 		__scm_destroy(scm);
35 }
36 
37 static __inline__ int scm_send(struct socket *sock, struct msghdr *msg,
38 			       struct scm_cookie *scm)
39 {
40 	memset(scm, 0, sizeof(*scm));
41 	scm->creds.uid = current->uid;
42 	scm->creds.gid = current->gid;
43 	scm->creds.pid = current->tgid;
44 	if (msg->msg_controllen <= 0)
45 		return 0;
46 	return __scm_send(sock, msg, scm);
47 }
48 
49 static __inline__ void scm_recv(struct socket *sock, struct msghdr *msg,
50 				struct scm_cookie *scm, int flags)
51 {
52 	if (!msg->msg_control)
53 	{
54 		if (test_bit(SOCK_PASSCRED, &sock->flags) || scm->fp)
55 			msg->msg_flags |= MSG_CTRUNC;
56 		scm_destroy(scm);
57 		return;
58 	}
59 
60 	if (test_bit(SOCK_PASSCRED, &sock->flags))
61 		put_cmsg(msg, SOL_SOCKET, SCM_CREDENTIALS, sizeof(scm->creds), &scm->creds);
62 
63 	if (!scm->fp)
64 		return;
65 
66 	scm_detach_fds(msg, scm);
67 }
68 
69 
70 #endif /* __LINUX_NET_SCM_H */
71 
72