This commit implements the SO_USER_COOKIE socket option, which lets

you tag a socket with an uint32_t value. The cookie can then be
used by the kernel for various purposes, e.g. setting the skipto
rule or pipe number in ipfw (this is the reason SO_USER_COOKIE has
been implemented; however there is nothing ipfw-specific in its
implementation).

The ipfw-related code that uses the optopn will be committed separately.

This change adds a field to 'struct socket', but the struct is not
part of any driver or userland-visible ABI so the change should be
harmless.

See the discussion at
http://lists.freebsd.org/pipermail/freebsd-ipfw/2009-October/004001.html

Idea and code from Paul Joe, small modifications and manpage
changes by myself.

Submitted by:	Paul Joe
MFC after:	1 week

1 files changed, 10 insertions, 0 deletions

diff --git a/sys/kern/uipc_socket.c b/sys/kern/uipc_socket.c
index d6c9854..e3e8e28 100644
--- a/sys/kern/uipc_socket.c
+++ b/sys/kern/uipc_socket.c
@@ -2386,6 +2386,7 @@ sosetopt(struct socket *so, struct sockopt *sopt)
 	struct	linger l;
 	struct	timeval tv;
 	u_long  val;
+	uint32_t val32;
 #ifdef MAC
 	struct mac extmac;
 #endif
@@ -2461,6 +2462,15 @@ sosetopt(struct socket *so, struct sockopt *sopt)
 				so->so_fibnum = 0;
 			}
 			break;
+
+		case SO_USER_COOKIE:
+			error = sooptcopyin(sopt, &val32, sizeof val32,
+					    sizeof val32);
+			if (error)
+				goto bad;
+			so->so_user_cookie = val32;
+			break;
+
 		case SO_SNDBUF:
 		case SO_RCVBUF:
 		case SO_SNDLOWAT: