link: AF_INET link module

Note: The code for this is not upstream yet.

Extends the link api to allow address family modules to fill a link
message and implements a AF_INET address family link module which
uses the new interface.

include/linux/if_link.h

@@ -147,6 +147,14 @@ enum {
 #define IFLA_PAYLOAD(n) NLMSG_PAYLOAD(n,sizeof(struct ifinfomsg))
 #endif
 
+enum {
+	IFLA_INET_UNSPEC,
+	IFLA_INET_CONF,
+	__IFLA_INET_MAX,
+};
+
+#define IFLA_INET_MAX (__IFLA_INET_MAX - 1)
+
 /* ifi_flags.
 
    IFF_* flags.

include/linux/inetdevice.h

@@ -0,0 +1,36 @@
+#ifndef _LINUX_INETDEVICE_H
+#define _LINUX_INETDEVICE_H
+
+enum
+{
+	IPV4_DEVCONF_FORWARDING=1,
+	IPV4_DEVCONF_MC_FORWARDING,
+	IPV4_DEVCONF_PROXY_ARP,
+	IPV4_DEVCONF_ACCEPT_REDIRECTS,
+	IPV4_DEVCONF_SECURE_REDIRECTS,
+	IPV4_DEVCONF_SEND_REDIRECTS,
+	IPV4_DEVCONF_SHARED_MEDIA,
+	IPV4_DEVCONF_RP_FILTER,
+	IPV4_DEVCONF_ACCEPT_SOURCE_ROUTE,
+	IPV4_DEVCONF_BOOTP_RELAY,
+	IPV4_DEVCONF_LOG_MARTIANS,
+	IPV4_DEVCONF_TAG,
+	IPV4_DEVCONF_ARPFILTER,
+	IPV4_DEVCONF_MEDIUM_ID,
+	IPV4_DEVCONF_NOXFRM,
+	IPV4_DEVCONF_NOPOLICY,
+	IPV4_DEVCONF_FORCE_IGMP_VERSION,
+	IPV4_DEVCONF_ARP_ANNOUNCE,
+	IPV4_DEVCONF_ARP_IGNORE,
+	IPV4_DEVCONF_PROMOTE_SECONDARIES,
+	IPV4_DEVCONF_ARP_ACCEPT,
+	IPV4_DEVCONF_ARP_NOTIFY,
+	IPV4_DEVCONF_ACCEPT_LOCAL,
+	IPV4_DEVCONF_SRC_VMARK,
+	IPV4_DEVCONF_PROXY_ARP_PVLAN,
+	__IPV4_DEVCONF_MAX
+};
+
+#define IPV4_DEVCONF_MAX (__IPV4_DEVCONF_MAX - 1)
+
+#endif /* _LINUX_INETDEVICE_H */

include/netlink-local.h

@@ -48,7 +48,7 @@
 #include <linux/gen_stats.h>
 #include <linux/ip_mp_alg.h>
 #include <linux/atm.h>
-
+#include <linux/inetdevice.h>
 #include <linux/ipv6.h>
 #include <linux/snmp.h>
 

include/netlink/route/link/api.h

@@ -110,6 +110,11 @@ struct rtnl_link_af_ops
 	int		      (*ao_parse_af)(struct rtnl_link *,
 					     struct nlattr *, void *);
 
+	/** Called if a link message is sent to the kernel. Must append the
+	 * link address family specific attributes to the message. */
+	int		      (*ao_fill_af)(struct rtnl_link *,
+					    struct nl_msg *msg, void *);
+
 	/** Dump address family specific link attributes */
 	void		      (*ao_dump[NL_DUMP_MAX+1])(struct rtnl_link *,
 							struct nl_dump_params *,
@@ -118,6 +123,10 @@ struct rtnl_link_af_ops
 
 extern struct rtnl_link_af_ops *rtnl_link_af_ops_lookup(unsigned int);
 extern void			rtnl_link_af_ops_put(struct rtnl_link_af_ops *);
+extern void *			rtnl_link_af_alloc(struct rtnl_link *,
+						const struct rtnl_link_af_ops *);
+extern void *			rtnl_link_af_data(const struct rtnl_link *,
+						const struct rtnl_link_af_ops *);
 extern int			rtnl_link_af_register(struct rtnl_link_af_ops *);
 extern int			rtnl_link_af_unregister(struct rtnl_link_af_ops *);
 

include/netlink/route/link/inet.h

@@ -0,0 +1,29 @@
+/*
+ * netlink/route/link/inet.h	INET Link Module
+ *
+ *	This library is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU Lesser General Public
+ *	License as published by the Free Software Foundation version 2.1
+ *	of the License.
+ *
+ * Copyright (c) 2010 Thomas Graf <tgraf@suug.ch>
+ */
+
+#ifndef NETLINK_LINK_INET_H_
+#define NETLINK_LINK_INET_H_
+
+#include <netlink/netlink.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+extern const char *	rtnl_link_inet_devconf2str(int, char *, size_t);
+extern unsigned int	rtnl_link_inet_str2devconf(const char *);
+
+extern int		rtnl_link_inet_get_conf(struct rtnl_link *,
+						const unsigned int, uint32_t *);
+extern int		rtnl_link_inet_set_conf(struct rtnl_link *,
+						const unsigned int, uint32_t);
+
+#endif

lib/Makefile.am

@@ -59,7 +59,7 @@ libnl_route_la_SOURCES = \
 	route/cls/ematch/meta.c \
 	\
 	route/link/api.c route/link/vlan.c \
-	route/link/bridge.c route/link/inet6.c \
+	route/link/bridge.c route/link/inet6.c route/link/inet.c \
 	\
 	route/sch/blackhole.c route/sch/cbq.c route/sch/dsmark.c \
 	route/sch/fifo.c route/sch/htb.c route/sch/netem.c route/sch/prio.c \

lib/route/link.c

@@ -187,18 +187,14 @@ static struct rtnl_link_af_ops *af_lookup_and_alloc(struct rtnl_link *link,
 						    int family)
 {
 	struct rtnl_link_af_ops *af_ops;
+	void *data;
 
 	af_ops = rtnl_link_af_ops_lookup(family);
 	if (!af_ops)
 		return NULL;
 
-	if (!link->l_af_data[family] && af_ops->ao_alloc) {
-		link->l_af_data[family] = af_ops->ao_alloc(link);
-		if (!link->l_af_data[family]) {
-			rtnl_link_af_ops_put(af_ops);
-			return NULL;
-		}
-	}
+	if (!(data = rtnl_link_af_data(link, af_ops)))
+		return NULL;
 
 	return af_ops;
 }
@@ -226,6 +222,27 @@ static int af_clone(struct rtnl_link *link, struct rtnl_link_af_ops *ops,
 	return 0;
 }
 
+static int af_fill(struct rtnl_link *link, struct rtnl_link_af_ops *ops,
+		   void *data, void *arg)
+{
+	struct nl_msg *msg = arg;
+	struct nlattr *af_attr;
+	int err;
+
+	if (!ops->ao_fill_af)
+		return 0;
+
+	if (!(af_attr = nla_nest_start(msg, ops->ao_family)))
+		return -NLE_MSGSIZE;
+
+	if ((err = ops->ao_fill_af(link, arg, data)) < 0)
+		return err;
+
+	nla_nest_end(msg, af_attr);
+
+	return 0;
+}
+
 static int af_dump_line(struct rtnl_link *link, struct rtnl_link_af_ops *ops,
 			 void *data, void *arg)
 {
@@ -1096,6 +1113,9 @@ int rtnl_link_build_change_request(struct rtnl_link *old,
 		nla_nest_end(msg, info);
 	}
 
+	if (do_foreach_af(tmpl, af_fill, msg) < 0)
+		goto nla_put_failure;
+
 	*result = msg;
 	return 0;
 

lib/route/link/api.c

@@ -190,6 +190,64 @@ void rtnl_link_af_ops_put(struct rtnl_link_af_ops *ops)
 		ops->ao_refcnt--;
 }
 
+/**
+ * Allocate and return data buffer for link address family modules
+ * @arg link		Link object
+ * @arg ops		Address family operations
+ *
+ * This function must be called by link address family modules in all
+ * cases where the API does not provide the data buffer as argument
+ * already. This typically includes set functions the module provides.
+ * Calling this function is strictly required to ensure proper allocation
+ * of the buffer upon first use. Link objects will NOT proactively
+ * allocate a data buffer for each registered link address family.
+ *
+ * @return Pointer to data buffer or NULL on error.
+ */
+void *rtnl_link_af_alloc(struct rtnl_link *link,
+			 const struct rtnl_link_af_ops *ops)
+{
+	int family;
+
+	if (!link || !ops)
+		BUG();
+
+	family = ops->ao_family;
+
+	if (!link->l_af_data[family]) {
+		if (!ops->ao_alloc)
+			BUG();
+		
+		link->l_af_data[family] = ops->ao_alloc(link);
+		if (!link->l_af_data[family])
+			return NULL;
+	}
+
+	return link->l_af_data[family];
+}
+
+/**
+ * Return data buffer for link address family modules
+ * @arg link		Link object
+ * @arg ops		Address family operations
+ *
+ * This function returns a pointer to the data buffer for the specified link
+ * address family module or NULL if the buffer was not allocated yet. This
+ * function is typically used by get functions of modules which are not
+ * interested in having the data buffer allocated if no values have been set
+ * yet.
+ *
+ * @return Pointer to data buffer or NULL on error.
+ */
+void *rtnl_link_af_data(const struct rtnl_link *link,
+			const struct rtnl_link_af_ops *ops)
+{
+	if (!link || !ops)
+		BUG();
+
+	return link->l_af_data[ops->ao_family];
+}
+
 /**
  * Register operations for a link address family
  * @arg ops		Address family operations

lib/route/link/inet.c

@@ -0,0 +1,228 @@
+/*
+ * lib/route/link/inet.c	AF_INET link operations
+ *
+ *	This library is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU Lesser General Public
+ *	License as published by the Free Software Foundation version 2.1
+ *	of the License.
+ *
+ * Copyright (c) 2010 Thomas Graf <tgraf@suug.ch>
+ */
+
+#include <netlink-local.h>
+#include <netlink/netlink.h>
+#include <netlink/attr.h>
+#include <netlink/route/rtnl.h>
+#include <netlink/route/link/api.h>
+
+struct inet_data
+{
+	uint8_t			i_confset[IPV4_DEVCONF_MAX];
+	uint32_t		i_conf[IPV4_DEVCONF_MAX];
+};
+
+static void *inet_alloc(struct rtnl_link *link)
+{
+	return calloc(1, sizeof(struct inet_data));
+}
+
+static void *inet_clone(struct rtnl_link *link, void *data)
+{
+	struct inet_data *id;
+
+	if ((id = inet_alloc(link)))
+		memcpy(id, data, sizeof(*id));
+
+	return id;
+}
+
+static void inet_free(struct rtnl_link *link, void *data)
+{
+	free(data);
+}
+
+static struct nla_policy inet_policy[IFLA_INET6_MAX+1] = {
+	[IFLA_INET_CONF]	= { .minlen = IPV4_DEVCONF_MAX * 4 },
+};
+
+static int inet_parse_af(struct rtnl_link *link, struct nlattr *attr, void *data)
+{
+	struct inet_data *id = data;
+	struct nlattr *tb[IFLA_INET_MAX+1];
+	int err;
+
+	err = nla_parse_nested(tb, IFLA_INET_MAX, attr, inet_policy);
+	if (err < 0)
+		return err;
+
+	if (tb[IFLA_INET_CONF])
+		nla_memcpy(&id->i_conf, tb[IFLA_INET_CONF], sizeof(id->i_conf));
+
+	return 0;
+}
+
+static int inet_fill_af(struct rtnl_link *link, struct nl_msg *msg, void *data)
+{
+	struct inet_data *id = data;
+	struct nlattr *nla;
+	int i;
+
+	if (!(nla = nla_nest_start(msg, IFLA_INET_CONF)))
+		return -NLE_MSGSIZE;
+
+	for (i = 0; i < IPV4_DEVCONF_MAX; i++)
+		if (id->i_confset[i])
+			NLA_PUT_U32(msg, i+1, id->i_conf[i]);
+
+	nla_nest_end(msg, nla);
+
+	return 0;
+
+nla_put_failure:
+	return -NLE_MSGSIZE;
+}
+
+static struct trans_tbl inet_devconf[] = {
+	__ADD(IPV4_DEVCONF_FORWARDING, forwarding)
+	__ADD(IPV4_DEVCONF_MC_FORWARDING, mc_forwarding)
+	__ADD(IPV4_DEVCONF_PROXY_ARP, proxy_arp)
+	__ADD(IPV4_DEVCONF_ACCEPT_REDIRECTS, accept_redirects)
+	__ADD(IPV4_DEVCONF_SECURE_REDIRECTS, secure_redirects)
+	__ADD(IPV4_DEVCONF_SEND_REDIRECTS, send_redirects)
+	__ADD(IPV4_DEVCONF_SHARED_MEDIA, shared_media)
+	__ADD(IPV4_DEVCONF_RP_FILTER, rp_filter)
+	__ADD(IPV4_DEVCONF_ACCEPT_SOURCE_ROUTE, accept_source_route)
+	__ADD(IPV4_DEVCONF_BOOTP_RELAY, bootp_relay)
+	__ADD(IPV4_DEVCONF_LOG_MARTIANS, log_martians)
+	__ADD(IPV4_DEVCONF_TAG, tag)
+	__ADD(IPV4_DEVCONF_ARPFILTER, arpfilter)
+	__ADD(IPV4_DEVCONF_MEDIUM_ID, medium_id)
+	__ADD(IPV4_DEVCONF_NOXFRM, noxfrm)
+	__ADD(IPV4_DEVCONF_NOPOLICY, nopolicy)
+	__ADD(IPV4_DEVCONF_FORCE_IGMP_VERSION, force_igmp_version)
+	__ADD(IPV4_DEVCONF_ARP_ANNOUNCE, arp_announce)
+	__ADD(IPV4_DEVCONF_ARP_IGNORE, arp_ignore)
+	__ADD(IPV4_DEVCONF_PROMOTE_SECONDARIES, promote_secondaries)
+	__ADD(IPV4_DEVCONF_ARP_ACCEPT, arp_accept)
+	__ADD(IPV4_DEVCONF_ARP_NOTIFY, arp_notify)
+	__ADD(IPV4_DEVCONF_ACCEPT_LOCAL, accept_local)
+	__ADD(IPV4_DEVCONF_SRC_VMARK, src_vmark)
+	__ADD(IPV4_DEVCONF_PROXY_ARP_PVLAN, proxy_arp_pvlan)
+};
+
+const char *rtnl_link_inet_devconf2str(int type, char *buf, size_t len)
+{
+	return __type2str(type, buf, len, inet_devconf,
+			  ARRAY_SIZE(inet_devconf));
+}
+
+unsigned int rtnl_link_inet_str2devconf(const char *name)
+{
+	return __str2type(name, inet_devconf, ARRAY_SIZE(inet_devconf));
+}
+
+static void inet_dump_details(struct rtnl_link *link,
+			      struct nl_dump_params *p, void *data)
+{
+	struct inet_data *id = data;
+	char buf[64];
+	int i, n = 0;
+
+	nl_dump_line(p, "    ipv4 devconf:\n");
+	nl_dump_line(p, "      ");
+
+	for (i = 0; i < IPV4_DEVCONF_MAX; i++) {
+		nl_dump_line(p, "%s %u",
+			rtnl_link_inet_devconf2str(i+1, buf, sizeof(buf)),
+			id->i_conf[i]);
+
+		if (++n == 4) {
+			nl_dump(p, "\n");
+			nl_dump_line(p, "      ");
+			n = 0;
+		} else
+			nl_dump(p, " ");
+	}
+
+	if (n != 0)
+		nl_dump(p, "\n");
+}
+
+static struct rtnl_link_af_ops inet_ops = {
+	.ao_family			= AF_INET,
+	.ao_alloc			= &inet_alloc,
+	.ao_clone			= &inet_clone,
+	.ao_free			= &inet_free,
+	.ao_parse_af			= &inet_parse_af,
+	.ao_fill_af			= &inet_fill_af,
+	.ao_dump[NL_DUMP_DETAILS]	= &inet_dump_details,
+};
+
+/**
+ * Get value of a ipv4 link configuration setting
+ * @arg link		Link object
+ * @arg cfgid		Configuration identifier
+ * @arg res		Result pointer
+ *
+ * Stores the value of the specified configuration setting in the provided
+ * result pointer.
+ *
+ * @return 0 on success or a negative error code.
+ * @return -NLE_RANGE cfgid is out of range, 1..IPV4_DEVCONF_MAX
+ * @return -NLE_NOATTR configuration setting not available
+ */
+int rtnl_link_inet_get_conf(struct rtnl_link *link, const unsigned int cfgid,
+			    uint32_t *res)
+{
+	struct inet_data *id;
+
+	if (cfgid == 0 || cfgid > IPV4_DEVCONF_MAX)
+		return -NLE_RANGE;
+
+	if (!(id = rtnl_link_af_alloc(link, &inet_ops)))
+		return -NLE_NOATTR;
+
+	*res = id->i_conf[cfgid];
+
+	return 0;
+}
+
+/**
+ * Change value of a ipv4 link configuration setting
+ * @arg link		Link object
+ * @arg cfgid		Configuration identifier
+ * @arg value		New value
+ *
+ * Changes the value in the per link ipv4 configuration array. 
+ *
+ * @return 0 on success or a negative error code.
+ * @return -NLE_RANGE cfgid is out of range, 1..IPV4_DEVCONF_MAX
+ * @return -NLE_NOMEM memory allocation failed
+ */
+int rtnl_link_inet_set_conf(struct rtnl_link *link, const unsigned int cfgid,
+			    uint32_t value)
+{
+	struct inet_data *id;
+
+	if (!(id = rtnl_link_af_alloc(link, &inet_ops)))
+		return -NLE_NOMEM;
+
+	if (cfgid == 0 || cfgid > IPV4_DEVCONF_MAX)
+		return -NLE_RANGE;
+
+	id->i_confset[cfgid - 1] = 1;
+	id->i_conf[cfgid - 1] = value;
+
+	return 0;
+}
+
+
+static void __init inet_init(void)
+{
+	rtnl_link_af_register(&inet_ops);
+}
+
+static void __exit inet_exit(void)
+{
+	rtnl_link_af_unregister(&inet_ops);
+}