Add netlink domain sockets support to socketutils

* linux/netlink_diag.h: New file.
* Makefile.am (EXTRA_DIST): Add it.
* socketutils.c: Include it and "xlat/netlink_protocols.h".
(netlink_send_query, netlink_parse_response, netlink_print): New
functions.
(print_sockaddr_by_inode): Hook up netlink_print.

Makefile.am

@@ -436,6 +436,7 @@ EXTRA_DIST =				\
 	linux/mips/syscallent.h		\
 	linux/mips/userent.h		\
 	linux/mtd-abi.h			\
+	linux/netlink_diag.h		\
 	linux/nios2/arch_regs.c		\
 	linux/nios2/get_error.c		\
 	linux/nios2/get_scno.c		\

linux/netlink_diag.h

@@ -0,0 +1,24 @@
+struct netlink_diag_req {
+	uint8_t sdiag_family;
+	uint8_t sdiag_protocol;
+	uint16_t pad;
+	uint32_t ndiag_ino;
+	uint32_t ndiag_show;
+	uint32_t ndiag_cookie[2];
+};
+
+struct netlink_diag_msg {
+	uint8_t ndiag_family;
+	uint8_t ndiag_type;
+	uint8_t ndiag_protocol;
+	uint8_t ndiag_state;
+
+	uint32_t ndiag_portid;
+	uint32_t ndiag_dst_portid;
+	uint32_t ndiag_dst_group;
+	uint32_t ndiag_ino;
+	uint32_t ndiag_cookie[2];
+};
+
+#define NDIAG_SHOW_MEMINFO           0x00000001
+#define NDIAG_PROTO_ALL              ((uint8_t) ~0)

socketutils.c

@@ -34,7 +34,9 @@
 #include <linux/sock_diag.h>
 #include <linux/inet_diag.h>
 #include <linux/unix_diag.h>
+#include <linux/netlink_diag.h>
 #include <linux/rtnetlink.h>
+#include "xlat/netlink_protocols.h"
 
 #if !defined NETLINK_SOCK_DIAG && defined NETLINK_INET_DIAG
 # define NETLINK_SOCK_DIAG NETLINK_INET_DIAG
@@ -334,6 +336,65 @@ unix_parse_response(const char *proto_name, const void *data,
 	return cache_and_print_inode_details(inode, details);
 }
 
+static bool
+netlink_send_query(const int fd, const unsigned long inode)
+{
+	struct {
+		const struct nlmsghdr nlh;
+		const struct netlink_diag_req ndr;
+	} req = {
+		.nlh = {
+			.nlmsg_len = sizeof(req),
+			.nlmsg_type = SOCK_DIAG_BY_FAMILY,
+			.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST
+		},
+		.ndr = {
+			.sdiag_family = AF_NETLINK,
+			.sdiag_protocol = NDIAG_PROTO_ALL,
+			.ndiag_show = NDIAG_SHOW_MEMINFO
+		}
+	};
+	return send_query(fd, &req, sizeof(req));
+}
+
+static int
+netlink_parse_response(const char *proto_name, const void *data,
+		    const int data_len, const unsigned long inode)
+{
+	const struct netlink_diag_msg *const diag_msg = data;
+	const char *netlink_proto;
+	char *details;
+
+	if (data_len < (int) NLMSG_LENGTH(sizeof(*diag_msg)))
+		return -1;
+	if (diag_msg->ndiag_ino != inode)
+		return 0;
+
+	if (diag_msg->ndiag_family != AF_NETLINK)
+		return -1;
+
+	netlink_proto = xlookup(netlink_protocols,
+				diag_msg->ndiag_protocol);
+
+	if (netlink_proto) {
+		static const char netlink_prefix[] = "NETLINK_";
+		const size_t netlink_prefix_len =
+			sizeof(netlink_prefix) -1;
+		if (strncmp(netlink_proto, netlink_prefix,
+			    netlink_prefix_len) == 0)
+			netlink_proto += netlink_prefix_len;
+		if (asprintf(&details, "%s:[%s:%u]", proto_name,
+			     netlink_proto, diag_msg->ndiag_portid) < 0)
+			return -1;
+	} else {
+		if (asprintf(&details, "%s:[%u]", proto_name,
+			     (unsigned) diag_msg->ndiag_protocol) < 0)
+			return -1;
+	}
+
+	return cache_and_print_inode_details(inode, details);
+}
+
 static bool
 unix_print(const int fd, const unsigned long inode)
 {
@@ -365,6 +426,14 @@ udp_v6_print(const int fd, const unsigned long inode)
 	return inet_print(fd, AF_INET6, IPPROTO_UDP, inode, "UDPv6");
 }
 
+static bool
+netlink_print(const int fd, const unsigned long inode)
+{
+	return netlink_send_query(fd, inode)
+		&& receive_responses(fd, inode, "NETLINK",
+				     netlink_parse_response);
+}
+
 /* Given an inode number of a socket, print out the details
  * of the ip address and port. */
 bool
@@ -378,7 +447,8 @@ print_sockaddr_by_inode(const unsigned long inode, const char *const proto_name)
 		{ "UDP", udp_v4_print },
 		{ "TCPv6", tcp_v6_print },
 		{ "UDPv6", udp_v6_print },
-		{ "UNIX", unix_print }
+		{ "UNIX", unix_print },
+		{ "NETLINK", netlink_print }
 	};
 
 	const int fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_SOCK_DIAG);