netlink: Diag core and basic socket info dumping (v2)

The netlink_diag can be built as a module, just like it's done in
unix sockets.

The core dumping message carries the basic info about netlink sockets:
family, type and protocol, portis, dst_group, dst_portid, state.

Groups can be received as an optional parameter NETLINK_DIAG_GROUPS.

Netlink sockets cab be filtered by protocols.

The socket inode number and cookie is reserved for future per-socket info
retrieving. The per-protocol filtering is also reserved for future by
requiring the sdiag_protocol to be zero.

The file /proc/net/netlink doesn't provide enough information for
dumping netlink sockets. It doesn't provide dst_group, dst_portid,
groups above 32.

v2: fix NETLINK_DIAG_MAX. Now it's equal to the last constant.

Acked-by: Pavel Emelyanov <xemul@parallels.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Gao feng <gaofeng@cn.fujitsu.com>
Cc: Thomas Graf <tgraf@suug.ch>
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/uapi/linux/netlink_diag.h b/include/uapi/linux/netlink_diag.h
new file mode 100644 (file)
index 0000000..88009a3
--- /dev/null
+++ b/include/uapi/linux/netlink_diag.h
@@ -0,0 +1,42 @@
+#ifndef __NETLINK_DIAG_H__
+#define __NETLINK_DIAG_H__
+
+#include <linux/types.h>
+
+struct netlink_diag_req {
+       __u8    sdiag_family;
+       __u8    sdiag_protocol;
+       __u16   pad;
+       __u32   ndiag_ino;
+       __u32   ndiag_show;
+       __u32   ndiag_cookie[2];
+};
+
+struct netlink_diag_msg {
+       __u8    ndiag_family;
+       __u8    ndiag_type;
+       __u8    ndiag_protocol;
+       __u8    ndiag_state;
+
+       __u32   ndiag_portid;
+       __u32   ndiag_dst_portid;
+       __u32   ndiag_dst_group;
+       __u32   ndiag_ino;
+       __u32   ndiag_cookie[2];
+};
+
+enum {
+       NETLINK_DIAG_MEMINFO,
+       NETLINK_DIAG_GROUPS,
+
+       __NETLINK_DIAG_MAX,
+};
+
+#define NETLINK_DIAG_MAX (__NETLINK_DIAG_MAX - 1)
+
+#define NDIAG_PROTO_ALL                ((__u8) ~0)
+
+#define NDIAG_SHOW_MEMINFO     0x00000001 /* show memory info of a socket */
+#define NDIAG_SHOW_GROUPS      0x00000002 /* show groups of a netlink socket */
+
+#endif

diff --git a/net/Kconfig b/net/Kconfig
index 6f676ab885be52b442fea9a0d0f0898e67da50a2..2ddc9046868e7a19d06841054696773242099ccf 100644 (file)
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -217,6 +217,7 @@ source "net/dns_resolver/Kconfig"
 source "net/batman-adv/Kconfig"
 source "net/openvswitch/Kconfig"
 source "net/vmw_vsock/Kconfig"
+source "net/netlink/Kconfig"
 
 config RPS
        boolean

diff --git a/net/netlink/Kconfig b/net/netlink/Kconfig
new file mode 100644 (file)
index 0000000..5d6e8c0
--- /dev/null
+++ b/net/netlink/Kconfig
@@ -0,0 +1,10 @@
+#
+# Netlink Sockets
+#
+
+config NETLINK_DIAG
+       tristate "NETLINK: socket monitoring interface"
+       default n
+       ---help---
+         Support for NETLINK socket monitoring interface used by the ss tool.
+         If unsure, say Y.

diff --git a/net/netlink/Makefile b/net/netlink/Makefile
index bdd6ddf4e95beb401ddd883f7caa00b9be389b9d..e837917f6c03e919dbaa555e4a984a1a3fc0ad58 100644 (file)
--- a/net/netlink/Makefile
+++ b/net/netlink/Makefile
@@ -3,3 +3,6 @@
 #
 
 obj-y                                  := af_netlink.o genetlink.o
+
+obj-$(CONFIG_NETLINK_DIAG)     += netlink_diag.o
+netlink_diag-y                 := diag.o

diff --git a/net/netlink/diag.c b/net/netlink/diag.c
new file mode 100644 (file)
index 0000000..5ffb1d1
--- /dev/null
+++ b/net/netlink/diag.c
@@ -0,0 +1,188 @@
+#include <linux/module.h>
+
+#include <net/sock.h>
+#include <linux/netlink.h>
+#include <linux/sock_diag.h>
+#include <linux/netlink_diag.h>
+
+#include "af_netlink.h"
+
+static int sk_diag_dump_groups(struct sock *sk, struct sk_buff *nlskb)
+{
+       struct netlink_sock *nlk = nlk_sk(sk);
+
+       if (nlk->groups == NULL)
+               return 0;
+
+       return nla_put(nlskb, NETLINK_DIAG_GROUPS, NLGRPSZ(nlk->ngroups),
+                      nlk->groups);
+}
+
+static int sk_diag_fill(struct sock *sk, struct sk_buff *skb,
+                       struct netlink_diag_req *req,
+                       u32 portid, u32 seq, u32 flags, int sk_ino)
+{
+       struct nlmsghdr *nlh;
+       struct netlink_diag_msg *rep;
+       struct netlink_sock *nlk = nlk_sk(sk);
+
+       nlh = nlmsg_put(skb, portid, seq, SOCK_DIAG_BY_FAMILY, sizeof(*rep),
+                       flags);
+       if (!nlh)
+               return -EMSGSIZE;
+
+       rep = nlmsg_data(nlh);
+       rep->ndiag_family       = AF_NETLINK;
+       rep->ndiag_type         = sk->sk_type;
+       rep->ndiag_protocol     = sk->sk_protocol;
+       rep->ndiag_state        = sk->sk_state;
+
+       rep->ndiag_ino          = sk_ino;
+       rep->ndiag_portid       = nlk->portid;
+       rep->ndiag_dst_portid   = nlk->dst_portid;
+       rep->ndiag_dst_group    = nlk->dst_group;
+       sock_diag_save_cookie(sk, rep->ndiag_cookie);
+
+       if ((req->ndiag_show & NDIAG_SHOW_GROUPS) &&
+           sk_diag_dump_groups(sk, skb))
+               goto out_nlmsg_trim;
+
+       if ((req->ndiag_show & NDIAG_SHOW_MEMINFO) &&
+           sock_diag_put_meminfo(sk, skb, NETLINK_DIAG_MEMINFO))
+               goto out_nlmsg_trim;
+
+       return nlmsg_end(skb, nlh);
+
+out_nlmsg_trim:
+       nlmsg_cancel(skb, nlh);
+       return -EMSGSIZE;
+}
+
+static int __netlink_diag_dump(struct sk_buff *skb, struct netlink_callback *cb,
+                               int protocol, int s_num)
+{
+       struct netlink_table *tbl = &nl_table[protocol];
+       struct nl_portid_hash *hash = &tbl->hash;
+       struct net *net = sock_net(skb->sk);
+       struct netlink_diag_req *req;
+       struct sock *sk;
+       int ret = 0, num = 0, i;
+
+       req = nlmsg_data(cb->nlh);
+
+       for (i = 0; i <= hash->mask; i++) {
+               sk_for_each(sk, &hash->table[i]) {
+                       if (!net_eq(sock_net(sk), net))
+                               continue;
+                       if (num < s_num) {
+                               num++;
+                               continue;
+                       }
+
+                       if (sk_diag_fill(sk, skb, req,
+                                        NETLINK_CB(cb->skb).portid,
+                                        cb->nlh->nlmsg_seq,
+                                        NLM_F_MULTI,
+                                        sock_i_ino(sk)) < 0) {
+                               ret = 1;
+                               goto done;
+                       }
+
+                       num++;
+               }
+       }
+
+       sk_for_each_bound(sk, &tbl->mc_list) {
+               if (sk_hashed(sk))
+                       continue;
+               if (!net_eq(sock_net(sk), net))
+                       continue;
+               if (num < s_num) {
+                       num++;
+                       continue;
+               }
+
+               if (sk_diag_fill(sk, skb, req,
+                                NETLINK_CB(cb->skb).portid,
+                                cb->nlh->nlmsg_seq,
+                                NLM_F_MULTI,
+                                sock_i_ino(sk)) < 0) {
+                       ret = 1;
+                       goto done;
+               }
+               num++;
+       }
+done:
+       cb->args[0] = num;
+       cb->args[1] = protocol;
+
+       return ret;
+}
+
+static int netlink_diag_dump(struct sk_buff *skb, struct netlink_callback *cb)
+{
+       struct netlink_diag_req *req;
+       int s_num = cb->args[0];
+
+       req = nlmsg_data(cb->nlh);
+
+       read_lock(&nl_table_lock);
+
+       if (req->sdiag_protocol == NDIAG_PROTO_ALL) {
+               int i;
+
+               for (i = cb->args[1]; i < MAX_LINKS; i++) {
+                       if (__netlink_diag_dump(skb, cb, i, s_num))
+                               break;
+                       s_num = 0;
+               }
+       } else {
+               if (req->sdiag_protocol >= MAX_LINKS) {
+                       read_unlock(&nl_table_lock);
+                       return -ENOENT;
+               }
+
+               __netlink_diag_dump(skb, cb, req->sdiag_protocol, s_num);
+       }
+
+       read_unlock(&nl_table_lock);
+
+       return skb->len;
+}
+
+static int netlink_diag_handler_dump(struct sk_buff *skb, struct nlmsghdr *h)
+{
+       int hdrlen = sizeof(struct netlink_diag_req);
+       struct net *net = sock_net(skb->sk);
+
+       if (nlmsg_len(h) < hdrlen)
+               return -EINVAL;
+
+       if (h->nlmsg_flags & NLM_F_DUMP) {
+               struct netlink_dump_control c = {
+                       .dump = netlink_diag_dump,
+               };
+               return netlink_dump_start(net->diag_nlsk, skb, h, &c);
+       } else
+               return -EOPNOTSUPP;
+}
+
+static const struct sock_diag_handler netlink_diag_handler = {
+       .family = AF_NETLINK,
+       .dump = netlink_diag_handler_dump,
+};
+
+static int __init netlink_diag_init(void)
+{
+       return sock_diag_register(&netlink_diag_handler);
+}
+
+static void __exit netlink_diag_exit(void)
+{
+       sock_diag_unregister(&netlink_diag_handler);
+}
+
+module_init(netlink_diag_init);
+module_exit(netlink_diag_exit);
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, 16 /* AF_NETLINK */);