From 2aac7a2cb0d9d8c65fc7dde3e19e46b3e878d23d Mon Sep 17 00:00:00 2001 From: Pavel Emelyanov Date: Thu, 15 Dec 2011 02:46:14 +0000 Subject: [PATCH] unix_diag: Pending connections IDs NLA When establishing a unix connection on stream sockets the server end receives an skb with socket in its receive queue. Report who is waiting for these ends to be accepted for listening sockets via NLA. There's a lokcing issue with this -- the unix sk state lock is required to access the peer, and it is taken under the listening sk's queue lock. Strictly speaking the queue lock should be taken inside the state lock, but since in this case these two sockets are different it shouldn't lead to deadlock. Signed-off-by: Pavel Emelyanov Signed-off-by: David S. Miller --- include/linux/unix_diag.h | 2 ++ net/unix/diag.c | 39 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 41 insertions(+) diff --git a/include/linux/unix_diag.h b/include/linux/unix_diag.h index 2d74a86024ac..03ffb7de15b6 100644 --- a/include/linux/unix_diag.h +++ b/include/linux/unix_diag.h @@ -14,6 +14,7 @@ struct unix_diag_req { #define UDIAG_SHOW_NAME 0x00000001 /* show name (not path) */ #define UDIAG_SHOW_VFS 0x00000002 /* show VFS inode info */ #define UDIAG_SHOW_PEER 0x00000004 /* show peer socket info */ +#define UDIAG_SHOW_ICONS 0x00000008 /* show pending connections */ struct unix_diag_msg { __u8 udiag_family; @@ -29,6 +30,7 @@ enum { UNIX_DIAG_NAME, UNIX_DIAG_VFS, UNIX_DIAG_PEER, + UNIX_DIAG_ICONS, UNIX_DIAG_MAX, }; diff --git a/net/unix/diag.c b/net/unix/diag.c index 0e0fda786afe..24c7a65d9cb1 100644 --- a/net/unix/diag.c +++ b/net/unix/diag.c @@ -63,6 +63,41 @@ rtattr_failure: return -EMSGSIZE; } +static int sk_diag_dump_icons(struct sock *sk, struct sk_buff *nlskb) +{ + struct sk_buff *skb; + u32 *buf; + int i; + + if (sk->sk_state == TCP_LISTEN) { + spin_lock(&sk->sk_receive_queue.lock); + buf = UNIX_DIAG_PUT(nlskb, UNIX_DIAG_ICONS, sk->sk_receive_queue.qlen); + i = 0; + skb_queue_walk(&sk->sk_receive_queue, skb) { + struct sock *req, *peer; + + req = skb->sk; + /* + * The state lock is outer for the same sk's + * queue lock. With the other's queue locked it's + * OK to lock the state. + */ + unix_state_lock_nested(req); + peer = unix_sk(req)->peer; + if (peer) + buf[i++] = sock_i_ino(peer); + unix_state_unlock(req); + } + spin_unlock(&sk->sk_receive_queue.lock); + } + + return 0; + +rtattr_failure: + spin_unlock(&sk->sk_receive_queue.lock); + return -EMSGSIZE; +} + static int sk_diag_fill(struct sock *sk, struct sk_buff *skb, struct unix_diag_req *req, u32 pid, u32 seq, u32 flags, int sk_ino) { @@ -93,6 +128,10 @@ static int sk_diag_fill(struct sock *sk, struct sk_buff *skb, struct unix_diag_r sk_diag_dump_peer(sk, skb)) goto nlmsg_failure; + if ((req->udiag_show & UDIAG_SHOW_ICONS) && + sk_diag_dump_icons(sk, skb)) + goto nlmsg_failure; + nlh->nlmsg_len = skb_tail_pointer(skb) - b; return skb->len; -- 2.39.5