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IPv4 FIB configuration rework

PATCH New Thomas Graf 2 participants 6 messages Aug 8, 2006

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Networking Network drivers IPv4/IPv6
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Thomas Graf

author
#0 lore raw

PATCH 1/1 IPv4 FIB configuration rework

Replaces the rather ugly struct kern_rta + rtmsg with a new struct fib_config while converting everything to the new netlink api. Simplifies the FIB module interface quite a bit and allows changing internals while keeping a stable netlink interface.

Gets rid of things like passing on netlink_skb_parms all around the fib code etc.

Also fixes some memory corruptions that could be triggered via netlink messages, not sure which would actually lead to an oops though.

author
#1 lore raw

PATCH 1/3 : FIB configuration using struct fib_config

Introduces struct fib_config replacing the ugly struct kern_rta prone to ordering issues. Avoids creating faked netlink messages for auto generated routes or requests via ioctl.

A new interface net/nexthop.h is added to help navigate through nexthop configuration arrays.

Since the netlink source pid of the requesting process is stored in fib_config, it is no longer required to pass netlink_skb_parms all along just for event notification.

Signed-off-by Thomas Graf <[email protected]>
include/net/ip_fib.h +42 -27
Index: net-2.6.19.git/include/net/ip_fib.h
===================================================================
@@ -20,25 +20,46 @@
 #include <linux/seq_file.h>
 #include <net/fib_rules.h>
 
-/* WARNING: The ordering of these elements must match ordering
- *          of RTA_* rtnetlink attribute numbers.
- */
-struct kern_rta {
-	void		*rta_dst;
-	void		*rta_src;
-	int		*rta_iif;
-	int		*rta_oif;
-	void		*rta_gw;
-	u32		*rta_priority;
-	void		*rta_prefsrc;
-	struct rtattr	*rta_mx;
-	struct rtattr	*rta_mp;
-	unsigned char	*rta_protoinfo;
-	u32		*rta_flow;
-	struct rta_cacheinfo *rta_ci;
-	struct rta_session *rta_sess;
-	u32		*rta_mp_alg;
-};
+struct fib_config {
+	u8			fc_family;
+	u8			fc_dst_len;
+	u8			fc_src_len;
+	u8			fc_tos;
+	u8			fc_protocol;
+	u8			fc_scope;
+	u8			fc_type;
+	/* 1 byte unused */
+	u32			fc_table;
+	u32			fc_flags;
+	u32			fc_dst;
+	u32			fc_src;
+	u32			fc_gw;
+	int			fc_oif;
+	u32			fc_priority;
+	u32			fc_prefsrc;
+	struct nlattr		*fc_mx;
+	struct rtnexthop	*fc_mp;
+	int			fc_mx_len;
+	int			fc_mp_len;
+	u32			fc_flow;
+	u32			fc_mp_alg;
+
+	/*
+	 * Request was issued via netlink, points to netlink header
+	 * to answer request
+	 */
+	struct nlmsghdr		*fc_nlh;
+
+	/*
+	 * Use separate field for netlink flags so non-netlink
+	 * sources are able to emulate it without providing a
+	 * complete header.
+	 */
+	u32			fc_nlmsg_flags;
+
+	/* Netlink PID of the process requesting the change */
+	u32			fc_pid;
+ };
 
 struct fib_info;
 

@@ -153,12 +174,8 @@ struct fib_table {
 	unsigned char	tb_id;
 	unsigned	tb_stamp;
 	int		(*tb_lookup)(struct fib_table *tb, const struct flowi *flp, struct fib_result *res);
-	int		(*tb_insert)(struct fib_table *table, struct rtmsg *r,
-				     struct kern_rta *rta, struct nlmsghdr *n,
-				     struct netlink_skb_parms *req);
-	int		(*tb_delete)(struct fib_table *table, struct rtmsg *r,
-				     struct kern_rta *rta, struct nlmsghdr *n,
-				     struct netlink_skb_parms *req);
+	int		(*tb_insert)(struct fib_table *, struct fib_config *);
+	int		(*tb_delete)(struct fib_table *, struct fib_config *);
 	int		(*tb_dump)(struct fib_table *table, struct sk_buff *skb,
 				     struct netlink_callback *cb);
 	int		(*tb_flush)(struct fib_table *table);

@@ -243,8 +260,6 @@ struct rtentry;
 extern int ip_fib_check_default(u32 gw, struct net_device *dev);
 extern int fib_sync_down(u32 local, struct net_device *dev, int force);
 extern int fib_sync_up(struct net_device *dev);
-extern int fib_convert_rtentry(int cmd, struct nlmsghdr *nl, struct rtmsg *rtm,
-			       struct kern_rta *rta, struct rtentry *r);
 extern u32  __fib_res_prefsrc(struct fib_result *res);
 
 /* Exported by fib_hash.c */
net/ipv4/fib_frontend.c +289 -70

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net/ipv4/fib_semantics.c +130 -276

583 lines not on this page · raw message

include/net/nexthop.h new file +33 -0
Index: net-2.6.19.git/include/net/nexthop.h
===================================================================
@@ -0,0 +1,33 @@
+#ifndef __NET_NEXTHOP_H
+#define __NET_NEXTHOP_H
+
+#include <linux/rtnetlink.h>
+#include <net/netlink.h>
+
+static inline int rtnh_ok(const struct rtnexthop *rtnh, int remaining)
+{
+	return remaining >= sizeof(*rtnh) &&
+	       rtnh->rtnh_len >= sizeof(*rtnh) &&
+	       rtnh->rtnh_len <= remaining;
+}
+
+static inline struct rtnexthop *rtnh_next(const struct rtnexthop *rtnh,
+                                         int *remaining)
+{
+	int totlen = NLA_ALIGN(rtnh->rtnh_len);
+
+	*remaining -= totlen;
+	return (struct rtnexthop *) ((char *) rtnh + totlen);
+}
+
+static inline struct nlattr *rtnh_attrs(const struct rtnexthop *rtnh)
+{
+	return (struct nlattr *) ((char *) rtnh + NLA_ALIGN(sizeof(*rtnh)));
+}
+
+static inline int rtnh_attrlen(const struct rtnexthop *rtnh)
+{
+	return rtnh->rtnh_len - NLA_ALIGN(sizeof(*rtnh));
+}
+
+#endif
net/ipv4/fib_hash.c +43 -50

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net/ipv4/fib_lookup.h +3 -8
Index: net-2.6.19.git/net/ipv4/fib_lookup.h
===================================================================
@@ -23,19 +23,14 @@ extern int fib_semantic_match(struct lis
 			      struct fib_result *res, __u32 zone, __u32 mask,
 				int prefixlen);
 extern void fib_release_info(struct fib_info *);
-extern struct fib_info *fib_create_info(const struct rtmsg *r,
-					struct kern_rta *rta,
-					const struct nlmsghdr *,
-					int *err);
-extern int fib_nh_match(struct rtmsg *r, struct nlmsghdr *,
-			struct kern_rta *rta, struct fib_info *fi);
+extern struct fib_info *fib_create_info(struct fib_config *cfg);
+extern int fib_nh_match(struct fib_config *cfg, struct fib_info *fi);
 extern int fib_dump_info(struct sk_buff *skb, u32 pid, u32 seq, int event,
 			 u8 tb_id, u8 type, u8 scope, void *dst,
 			 int dst_len, u8 tos, struct fib_info *fi,
 			 unsigned int);
 extern void rtmsg_fib(int event, u32 key, struct fib_alias *fa,
-		      int z, int tb_id,
-		      struct nlmsghdr *n, struct netlink_skb_parms *req);
+		      int dst_len, int tb_id, struct fib_config *cfg);
 extern struct fib_alias *fib_find_alias(struct list_head *fah,
 					u8 tos, u32 prio);
 extern int fib_detect_death(struct fib_info *fi, int order,
net/ipv4/fib_trie.c +28 -42

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author
#2 lore raw

Re: [PATCH 1/3] [IPv4]: FIB configuration using struct fib_config

* Thomas Graf <[email protected]> 2006-08-08 00:00

Quoted 10 lines

Introduces struct fib_config replacing the ugly struct kern_rta prone to ordering issues. Avoids creating faked netlink messages for auto generated routes or requests via ioctl.

A new interface net/nexthop.h is added to help navigate through nexthop configuration arrays.

Since the netlink source pid of the requesting process is stored in fib_config, it is no longer required to pass netlink_skb_parms all along just for event notification.

Hold on with this patch, netlink pid handling for netlink events is completely inconsistent. I want to figure out the right way to do it first.

maintainer
#3 lore raw

Re: [PATCH 1/3] [IPv4]: FIB configuration using struct fib_config

From: Thomas Graf <[email protected]>
Date: Wed, 9 Aug 2006 01:11:03 +0200

Quoted 3 lines

Hold on with this patch, netlink pid handling for netlink events is completely inconsistent. I want to figure out the right way to do it first.

Ok.

author
#4 lore raw

PATCH 2/3 : Convert FIB dumping to use new netlink api

In reply to Thomas Graf
Signed-off-by Thomas Graf <[email protected]>
net/ipv4/fib_semantics.c +47 -39
Index: net-2.6.19.git/net/ipv4/fib_semantics.c
===================================================================
@@ -286,7 +286,7 @@ void rtmsg_fib(int event, u32 key, struc
 		return;
 
 	if (fib_dump_info(skb, pid, seq, event, tb_id, fa->fa_type,
-			  fa->fa_scope, &key, dst_len, fa->fa_tos,
+			  fa->fa_scope, key, dst_len, fa->fa_tos,
 			  fa->fa_info, 0) <= 0) {
 		kfree_skb(skb);
 		return;

@@ -935,17 +935,18 @@ u32 __fib_res_prefsrc(struct fib_result 
 	return inet_select_addr(FIB_RES_DEV(*res), FIB_RES_GW(*res), res->scope);
 }
 
-int
-fib_dump_info(struct sk_buff *skb, u32 pid, u32 seq, int event,
-	      u8 tb_id, u8 type, u8 scope, void *dst, int dst_len, u8 tos,
-	      struct fib_info *fi, unsigned int flags)
+int fib_dump_info(struct sk_buff *skb, u32 pid, u32 seq, int event,
+		  u8 tb_id, u8 type, u8 scope, u32 dst, int dst_len, u8 tos,
+		  struct fib_info *fi, unsigned int flags)
 {
+	struct nlmsghdr *nlh;
 	struct rtmsg *rtm;
-	struct nlmsghdr  *nlh;
-	unsigned char	 *b = skb->tail;
 
-	nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*rtm), flags);
-	rtm = NLMSG_DATA(nlh);
+	nlh = nlmsg_put(skb, pid, seq, event, sizeof(*rtm), flags);
+	if (nlh == NULL)
+		return -ENOBUFS;
+
+	rtm = nlmsg_data(nlh);
 	rtm->rtm_family = AF_INET;
 	rtm->rtm_dst_len = dst_len;
 	rtm->rtm_src_len = 0;

@@ -954,59 +955,66 @@ fib_dump_info(struct sk_buff *skb, u32 p
 	rtm->rtm_type = type;
 	rtm->rtm_flags = fi->fib_flags;
 	rtm->rtm_scope = scope;
-	if (rtm->rtm_dst_len)
-		RTA_PUT(skb, RTA_DST, 4, dst);
 	rtm->rtm_protocol = fi->fib_protocol;
+
+	if (rtm->rtm_dst_len)
+		NLA_PUT_U32(skb, RTA_DST, dst);
+
 	if (fi->fib_priority)
-		RTA_PUT(skb, RTA_PRIORITY, 4, &fi->fib_priority);
+		NLA_PUT_U32(skb, RTA_PRIORITY, fi->fib_priority);
+
 	if (rtnetlink_put_metrics(skb, fi->fib_metrics) < 0)
-		goto rtattr_failure;
+		goto nla_put_failure;
+
 	if (fi->fib_prefsrc)
-		RTA_PUT(skb, RTA_PREFSRC, 4, &fi->fib_prefsrc);
+		NLA_PUT_U32(skb, RTA_PREFSRC, fi->fib_prefsrc);
+
 	if (fi->fib_nhs == 1) {
 		if (fi->fib_nh->nh_gw)
-			RTA_PUT(skb, RTA_GATEWAY, 4, &fi->fib_nh->nh_gw);
+			NLA_PUT_U32(skb, RTA_GATEWAY, fi->fib_nh->nh_gw);
+
 		if (fi->fib_nh->nh_oif)
-			RTA_PUT(skb, RTA_OIF, sizeof(int), &fi->fib_nh->nh_oif);
+			NLA_PUT_U32(skb, RTA_OIF, fi->fib_nh->nh_oif);
 #ifdef CONFIG_NET_CLS_ROUTE
 		if (fi->fib_nh[0].nh_tclassid)
-			RTA_PUT(skb, RTA_FLOW, 4, &fi->fib_nh[0].nh_tclassid);
+			NLA_PUT_U32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid);
 #endif
 	}
 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 	if (fi->fib_nhs > 1) {
-		struct rtnexthop *nhp;
-		struct rtattr *mp_head;
-		if (skb_tailroom(skb) <= RTA_SPACE(0))
-			goto rtattr_failure;
-		mp_head = (struct rtattr*)skb_put(skb, RTA_SPACE(0));
+		struct rtnexthop *rtnh;
+		struct nlattr *mp;
+
+		mp = nla_nest_start(skb, RTA_MULTIPATH);
+		if (mp == NULL)
+			goto nla_put_failure;
 
 		for_nexthops(fi) {
-			if (skb_tailroom(skb) < RTA_ALIGN(RTA_ALIGN(sizeof(*nhp)) + 4))
-				goto rtattr_failure;
-			nhp = (struct rtnexthop*)skb_put(skb, RTA_ALIGN(sizeof(*nhp)));
-			nhp->rtnh_flags = nh->nh_flags & 0xFF;
-			nhp->rtnh_hops = nh->nh_weight-1;
-			nhp->rtnh_ifindex = nh->nh_oif;
+			rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
+			if (rtnh == NULL)
+				goto nla_put_failure;
+
+			rtnh->rtnh_flags = nh->nh_flags & 0xFF;
+			rtnh->rtnh_hops = nh->nh_weight - 1;
+			rtnh->rtnh_ifindex = nh->nh_oif;
+
 			if (nh->nh_gw)
-				RTA_PUT(skb, RTA_GATEWAY, 4, &nh->nh_gw);
+				NLA_PUT_U32(skb, RTA_GATEWAY, nh->nh_gw);
 #ifdef CONFIG_NET_CLS_ROUTE
 			if (nh->nh_tclassid)
-				RTA_PUT(skb, RTA_FLOW, 4, &nh->nh_tclassid);
+				NLA_PUT_U32(skb, RTA_FLOW, nh->nh_tclassid);
 #endif
-			nhp->rtnh_len = skb->tail - (unsigned char*)nhp;
+			/* length of rtnetlink header + attributes */
+			rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *) rtnh;
 		} endfor_nexthops(fi);
-		mp_head->rta_type = RTA_MULTIPATH;
-		mp_head->rta_len = skb->tail - (u8*)mp_head;
+
+		nla_nest_end(skb, mp);
 	}
 #endif
-	nlh->nlmsg_len = skb->tail - b;
-	return skb->len;
+	return nlmsg_end(skb, nlh);
 
-nlmsg_failure:
-rtattr_failure:
-	skb_trim(skb, b - skb->data);
-	return -1;
+nla_put_failure:
+	return nlmsg_cancel(skb, nlh);
 }
 
 /*
net/ipv4/fib_hash.c +1 -1
Index: net-2.6.19.git/net/ipv4/fib_hash.c
===================================================================
@@ -692,7 +692,7 @@ fn_hash_dump_bucket(struct sk_buff *skb,
 					  tb->tb_id,
 					  fa->fa_type,
 					  fa->fa_scope,
-					  &f->fn_key,
+					  f->fn_key,
 					  fz->fz_order,
 					  fa->fa_tos,
 					  fa->fa_info,
net/ipv4/fib_trie.c +1 -1
Index: net-2.6.19.git/net/ipv4/fib_trie.c
===================================================================
@@ -1852,7 +1852,7 @@ static int fn_trie_dump_fa(t_key key, in
 				  tb->tb_id,
 				  fa->fa_type,
 				  fa->fa_scope,
-				  &xkey,
+				  xkey,
 				  plen,
 				  fa->fa_tos,
 				  fa->fa_info, 0) < 0) {
net/ipv4/fib_lookup.h +1 -1
Index: net-2.6.19.git/net/ipv4/fib_lookup.h
===================================================================
@@ -26,7 +26,7 @@ extern void fib_release_info(struct fib_
 extern struct fib_info *fib_create_info(struct fib_config *cfg);
 extern int fib_nh_match(struct fib_config *cfg, struct fib_info *fi);
 extern int fib_dump_info(struct sk_buff *skb, u32 pid, u32 seq, int event,
-			 u8 tb_id, u8 type, u8 scope, void *dst,
+			 u8 tb_id, u8 type, u8 scope, u32 dst,
 			 int dst_len, u8 tos, struct fib_info *fi,
 			 unsigned int);
 extern void rtmsg_fib(int event, u32 key, struct fib_alias *fa,
net/ipv4/route.c +32 -34

113 lines not on this page · raw message

net/ipv4/fib_frontend.c +2 -2
Index: net-2.6.19.git/net/ipv4/fib_frontend.c
===================================================================
@@ -563,8 +563,8 @@ int inet_dump_fib(struct sk_buff *skb, s
 	int s_t;
 	struct fib_table *tb;
 
-	if (NLMSG_PAYLOAD(cb->nlh, 0) >= sizeof(struct rtmsg) &&
-	    ((struct rtmsg*)NLMSG_DATA(cb->nlh))->rtm_flags&RTM_F_CLONED)
+	if (nlmsg_len(cb->nlh) >= sizeof(struct rtmsg) &&
+	    ((struct rtmsg *) nlmsg_data(cb->nlh))->rtm_flags & RTM_F_CLONED)
 		return ip_rt_dump(skb, cb);
 
 	s_t = cb->args[0];
author
#5 lore raw

PATCH 3/3 : Convert route get to new netlink api

In reply to Thomas Graf

Fixes various unvalidated netlink attributes causing memory corruptions when left empty by userspace applications.

Signed-off-by Thomas Graf <[email protected]>
include/net/ip_fib.h +1 -0
Index: net-2.6.19.git/include/net/ip_fib.h
===================================================================
@@ -245,6 +245,7 @@ extern void fib_select_default(const str
 #endif /* CONFIG_IP_MULTIPLE_TABLES */
 
 /* Exported by fib_frontend.c */
+extern struct nla_policy rtm_ipv4_policy[];
 extern void		ip_fib_init(void);
 extern int inet_rtm_delroute(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg);
 extern int inet_rtm_newroute(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg);
net/ipv4/fib_frontend.c +1 -1
Index: net-2.6.19.git/net/ipv4/fib_frontend.c
===================================================================
@@ -433,7 +433,7 @@ int ip_rt_ioctl(unsigned int cmd, void *
 
 #endif
 
-static struct nla_policy rtm_ipv4_policy[RTA_MAX+1] __read_mostly = {
+struct nla_policy rtm_ipv4_policy[RTA_MAX+1] __read_mostly = {
 	[RTA_DST]		= { .type = NLA_U32 },
 	[RTA_SRC]		= { .type = NLA_U32 },
 	[RTA_IIF]		= { .type = NLA_U32 },
net/ipv4/route.c +47 -39

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