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/net/netlink/Kconfig b/net/netlink/Kconfig
new file mode 100644
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 bdd6ddf..e837917 100644
--- 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
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 */);