[PATCH 0/3] [PATCHSET] netlink error management

[PATCH 0/3] [PATCHSET] netlink error management

[Thomas Graf]

This series of patches simplifies the error management and
signalization of dump starts of netlink_run_queue() message
handlers. It touches a fair bit of nfnetlink code as the
error pointer has been passed on to subsystems.

[PATCH 1/3] [NETLINK]: Remove error pointer from netlink message handler

[Thomas Graf]

[-- Attachment #1: netlink_run_queue_remove_errp --]
[-- Type: text/plain, Size: 18245 bytes --]

The error pointer argument in netlink message handlers is used
to signal the special case where processing has to be interrupted
because a dump was started but no error happened. Instead it is
simpler and more clear to return -EINTR and have netlink_run_queue()
deal with getting the queue right.

nfnetlink passed on this error pointer to its subsystem handlers
but only uses it to signal the start of a netlink dump. Therefore
it can be removed there as well.

This patch also cleans up the error handling in the affected
message handlers to be consistent since it had to be touched anyway.

Signed-off-by: Thomas Graf <tgraf@suug.ch>

Index: net-2.6.22/net/core/rtnetlink.c
===================================================================
--- net-2.6.22.orig/net/core/rtnetlink.c	2007-03-21 15:36:28.000000000 +0100
+++ net-2.6.22/net/core/rtnetlink.c	2007-03-21 18:38:32.000000000 +0100
@@ -851,8 +851,7 @@ static int rtattr_max;
 
 /* Process one rtnetlink message. */
 
-static __inline__ int
-rtnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, int *errp)
+static int rtnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 {
 	rtnl_doit_func doit;
 	int sz_idx, kind;
@@ -862,10 +861,8 @@ rtnetlink_rcv_msg(struct sk_buff *skb, s
 	int err;
 
 	type = nlh->nlmsg_type;
-
-	/* Unknown message: reply with EINVAL */
 	if (type > RTM_MAX)
-		goto err_inval;
+		return -EINVAL;
 
 	type -= RTM_BASE;
 
@@ -874,40 +871,33 @@ rtnetlink_rcv_msg(struct sk_buff *skb, s
 		return 0;
 
 	family = ((struct rtgenmsg*)NLMSG_DATA(nlh))->rtgen_family;
-	if (family >= NPROTO) {
-		*errp = -EAFNOSUPPORT;
-		return -1;
-	}
+	if (family >= NPROTO)
+		return -EAFNOSUPPORT;
 
 	sz_idx = type>>2;
 	kind = type&3;
 
-	if (kind != 2 && security_netlink_recv(skb, CAP_NET_ADMIN)) {
-		*errp = -EPERM;
-		return -1;
-	}
+	if (kind != 2 && security_netlink_recv(skb, CAP_NET_ADMIN))
+		return -EPERM;
 
 	if (kind == 2 && nlh->nlmsg_flags&NLM_F_DUMP) {
 		rtnl_dumpit_func dumpit;
 
 		dumpit = rtnl_get_dumpit(family, type);
 		if (dumpit == NULL)
-			goto err_inval;
+			return -EINVAL;
 
-		if ((*errp = netlink_dump_start(rtnl, skb, nlh,
-						dumpit, NULL)) != 0) {
-			return -1;
-		}
-
-		netlink_queue_skip(nlh, skb);
-		return -1;
+		err = netlink_dump_start(rtnl, skb, nlh, dumpit, NULL);
+		if (err == 0)
+			err = -EINTR;
+		return err;
 	}
 
 	memset(rta_buf, 0, (rtattr_max * sizeof(struct rtattr *)));
 
 	min_len = rtm_min[sz_idx];
 	if (nlh->nlmsg_len < min_len)
-		goto err_inval;
+		return -EINVAL;
 
 	if (nlh->nlmsg_len > min_len) {
 		int attrlen = nlh->nlmsg_len - NLMSG_ALIGN(min_len);
@@ -917,7 +907,7 @@ rtnetlink_rcv_msg(struct sk_buff *skb, s
 			unsigned flavor = attr->rta_type;
 			if (flavor) {
 				if (flavor > rta_max[sz_idx])
-					goto err_inval;
+					return -EINVAL;
 				rta_buf[flavor-1] = attr;
 			}
 			attr = RTA_NEXT(attr, attrlen);
@@ -926,15 +916,9 @@ rtnetlink_rcv_msg(struct sk_buff *skb, s
 
 	doit = rtnl_get_doit(family, type);
 	if (doit == NULL)
-		goto err_inval;
-	err = doit(skb, nlh, (void *)&rta_buf[0]);
-
-	*errp = err;
-	return err;
+		return -EINVAL;
 
-err_inval:
-	*errp = -EINVAL;
-	return -1;
+	return doit(skb, nlh, (void *)&rta_buf[0]);
 }
 
 static void rtnetlink_rcv(struct sock *sk, int len)
Index: net-2.6.22/net/netlink/genetlink.c
===================================================================
--- net-2.6.22.orig/net/netlink/genetlink.c	2007-03-21 15:42:18.000000000 +0100
+++ net-2.6.22/net/netlink/genetlink.c	2007-03-21 18:38:32.000000000 +0100
@@ -295,60 +295,49 @@ int genl_unregister_family(struct genl_f
 	return -ENOENT;
 }
 
-static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
-			       int *errp)
+static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 {
 	struct genl_ops *ops;
 	struct genl_family *family;
 	struct genl_info info;
 	struct genlmsghdr *hdr = nlmsg_data(nlh);
-	int hdrlen, err = -EINVAL;
+	int hdrlen, err;
 
 	family = genl_family_find_byid(nlh->nlmsg_type);
-	if (family == NULL) {
-		err = -ENOENT;
-		goto errout;
-	}
+	if (family == NULL)
+		return -ENOENT;
 
 	hdrlen = GENL_HDRLEN + family->hdrsize;
 	if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
-		goto errout;
+		return -EINVAL;
 
 	ops = genl_get_cmd(hdr->cmd, family);
-	if (ops == NULL) {
-		err = -EOPNOTSUPP;
-		goto errout;
-	}
+	if (ops == NULL)
+		return -EOPNOTSUPP;
 
-	if ((ops->flags & GENL_ADMIN_PERM) && security_netlink_recv(skb, CAP_NET_ADMIN)) {
-		err = -EPERM;
-		goto errout;
-	}
+	if ((ops->flags & GENL_ADMIN_PERM) &&
+	    security_netlink_recv(skb, CAP_NET_ADMIN))
+		return -EPERM;
 
 	if (nlh->nlmsg_flags & NLM_F_DUMP) {
-		if (ops->dumpit == NULL) {
-			err = -EOPNOTSUPP;
-			goto errout;
-		}
+		if (ops->dumpit == NULL)
+			return -EOPNOTSUPP;
 
-		*errp = err = netlink_dump_start(genl_sock, skb, nlh,
-						 ops->dumpit, ops->done);
+		err = netlink_dump_start(genl_sock, skb, nlh,
+					 ops->dumpit, ops->done);
 		if (err == 0)
-			skb_pull(skb, min(NLMSG_ALIGN(nlh->nlmsg_len),
-					  skb->len));
-		return -1;
+			err = -EINTR;
+		return err;
 	}
 
-	if (ops->doit == NULL) {
-		err = -EOPNOTSUPP;
-		goto errout;
-	}
+	if (ops->doit == NULL)
+		return -EOPNOTSUPP;
 
 	if (family->attrbuf) {
 		err = nlmsg_parse(nlh, hdrlen, family->attrbuf, family->maxattr,
 				  ops->policy);
 		if (err < 0)
-			goto errout;
+			return err;
 	}
 
 	info.snd_seq = nlh->nlmsg_seq;
@@ -358,12 +347,7 @@ static int genl_rcv_msg(struct sk_buff *
 	info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
 	info.attrs = family->attrbuf;
 
-	*errp = err = ops->doit(skb, &info);
-	return err;
-
-errout:
-	*errp = err;
-	return -1;
+	return ops->doit(skb, &info);
 }
 
 static void genl_rcv(struct sock *sk, int len)
Index: net-2.6.22/net/xfrm/xfrm_user.c
===================================================================
--- net-2.6.22.orig/net/xfrm/xfrm_user.c	2007-03-21 15:48:08.000000000 +0100
+++ net-2.6.22/net/xfrm/xfrm_user.c	2007-03-21 18:38:32.000000000 +0100
@@ -1853,46 +1853,39 @@ static struct xfrm_link {
 	[XFRM_MSG_MIGRATE     - XFRM_MSG_BASE] = { .doit = xfrm_do_migrate    },
 };
 
-static int xfrm_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, int *errp)
+static int xfrm_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 {
 	struct rtattr *xfrma[XFRMA_MAX];
 	struct xfrm_link *link;
-	int type, min_len;
+	int type, min_len, err;
 
 	type = nlh->nlmsg_type;
-
-	/* Unknown message: reply with EINVAL */
 	if (type > XFRM_MSG_MAX)
-		goto err_einval;
+		return -EINVAL;
 
 	type -= XFRM_MSG_BASE;
 	link = &xfrm_dispatch[type];
 
 	/* All operations require privileges, even GET */
-	if (security_netlink_recv(skb, CAP_NET_ADMIN)) {
-		*errp = -EPERM;
-		return -1;
-	}
+	if (security_netlink_recv(skb, CAP_NET_ADMIN))
+		return -EPERM;
 
 	if ((type == (XFRM_MSG_GETSA - XFRM_MSG_BASE) ||
 	     type == (XFRM_MSG_GETPOLICY - XFRM_MSG_BASE)) &&
 	    (nlh->nlmsg_flags & NLM_F_DUMP)) {
 		if (link->dump == NULL)
-			goto err_einval;
-
-		if ((*errp = netlink_dump_start(xfrm_nl, skb, nlh,
-						link->dump, NULL)) != 0) {
-			return -1;
-		}
+			return -EINVAL;
 
-		netlink_queue_skip(nlh, skb);
-		return -1;
+		err = netlink_dump_start(xfrm_nl, skb, nlh, link->dump, NULL);
+		if (err == 0)
+			err = -EINTR;
+		return err;
 	}
 
 	memset(xfrma, 0, sizeof(xfrma));
 
 	if (nlh->nlmsg_len < (min_len = xfrm_msg_min[type]))
-		goto err_einval;
+		return -EINVAL;
 
 	if (nlh->nlmsg_len > min_len) {
 		int attrlen = nlh->nlmsg_len - NLMSG_ALIGN(min_len);
@@ -1902,7 +1895,7 @@ static int xfrm_user_rcv_msg(struct sk_b
 			unsigned short flavor = attr->rta_type;
 			if (flavor) {
 				if (flavor > XFRMA_MAX)
-					goto err_einval;
+					return -EINVAL;
 				xfrma[flavor - 1] = attr;
 			}
 			attr = RTA_NEXT(attr, attrlen);
@@ -1910,14 +1903,9 @@ static int xfrm_user_rcv_msg(struct sk_b
 	}
 
 	if (link->doit == NULL)
-		goto err_einval;
-	*errp = link->doit(skb, nlh, xfrma);
-
-	return *errp;
+		return -EINVAL;
 
-err_einval:
-	*errp = -EINVAL;
-	return -1;
+	return link->doit(skb, nlh, xfrma);
 }
 
 static void xfrm_netlink_rcv(struct sock *sk, int len)
Index: net-2.6.22/net/netfilter/nfnetlink.c
===================================================================
--- net-2.6.22.orig/net/netfilter/nfnetlink.c	2007-03-21 15:49:41.000000000 +0100
+++ net-2.6.22/net/netfilter/nfnetlink.c	2007-03-21 17:44:24.000000000 +0100
@@ -195,17 +195,14 @@ int nfnetlink_unicast(struct sk_buff *sk
 EXPORT_SYMBOL_GPL(nfnetlink_unicast);
 
 /* Process one complete nfnetlink message. */
-static int nfnetlink_rcv_msg(struct sk_buff *skb,
-				    struct nlmsghdr *nlh, int *errp)
+static int nfnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 {
 	struct nfnl_callback *nc;
 	struct nfnetlink_subsystem *ss;
-	int type, err = 0;
+	int type, err;
 
-	if (security_netlink_recv(skb, CAP_NET_ADMIN)) {
-		*errp = -EPERM;
-		return -1;
-	}
+	if (security_netlink_recv(skb, CAP_NET_ADMIN))
+		return -EPERM;
 
 	/* All the messages must at least contain nfgenmsg */
 	if (nlh->nlmsg_len < NLMSG_SPACE(sizeof(struct nfgenmsg)))
@@ -223,12 +220,12 @@ static int nfnetlink_rcv_msg(struct sk_b
 		ss = nfnetlink_get_subsys(type);
 		if (!ss)
 #endif
-			goto err_inval;
+			return -EINVAL;
 	}
 
 	nc = nfnetlink_find_client(type, ss);
 	if (!nc)
-		goto err_inval;
+		return -EINVAL;
 
 	{
 		u_int16_t attr_count =
@@ -239,16 +236,9 @@ static int nfnetlink_rcv_msg(struct sk_b
 
 		err = nfnetlink_check_attributes(ss, nlh, cda);
 		if (err < 0)
-			goto err_inval;
-
-		err = nc->call(nfnl, skb, nlh, cda, errp);
-		*errp = err;
-		return err;
+			return err;
+		return nc->call(nfnl, skb, nlh, cda);
 	}
-
-err_inval:
-	*errp = -EINVAL;
-	return -1;
 }
 
 static void nfnetlink_rcv(struct sock *sk, int len)
Index: net-2.6.22/include/net/netlink.h
===================================================================
--- net-2.6.22.orig/include/net/netlink.h	2007-03-21 15:51:15.000000000 +0100
+++ net-2.6.22/include/net/netlink.h	2007-03-21 15:54:17.000000000 +0100
@@ -214,7 +214,7 @@ struct nl_info {
 
 extern void		netlink_run_queue(struct sock *sk, unsigned int *qlen,
 					  int (*cb)(struct sk_buff *,
-						    struct nlmsghdr *, int *));
+						    struct nlmsghdr *));
 extern void		netlink_queue_skip(struct nlmsghdr *nlh,
 					   struct sk_buff *skb);
 extern int		nlmsg_notify(struct sock *sk, struct sk_buff *skb,
Index: net-2.6.22/net/netlink/af_netlink.c
===================================================================
--- net-2.6.22.orig/net/netlink/af_netlink.c	2007-03-21 15:36:10.000000000 +0100
+++ net-2.6.22/net/netlink/af_netlink.c	2007-03-22 00:02:36.000000000 +0100
@@ -1463,7 +1463,7 @@ void netlink_ack(struct sk_buff *in_skb,
 }
 
 static int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
-						     struct nlmsghdr *, int *))
+						     struct nlmsghdr *))
 {
 	struct nlmsghdr *nlh;
 	int err;
@@ -1483,13 +1483,11 @@ static int netlink_rcv_skb(struct sk_buf
 		if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
 			goto skip;
 
-		if (cb(skb, nlh, &err) < 0) {
-			/* Not an error, but we have to interrupt processing
-			 * here. Note: that in this case we do not pull
-			 * message from skb, it will be processed later.
-			 */
-			if (err == 0)
-				return -1;
+		err = cb(skb, nlh);
+		if (err == -EINTR) {
+			/* Not an error, but we interrupt processing */
+			netlink_queue_skip(nlh, skb);
+			return err;
 		}
 skip:
 		if (nlh->nlmsg_flags & NLM_F_ACK || err)
@@ -1515,9 +1513,14 @@ skip:
  *
  * qlen must be initialized to 0 before the initial entry, afterwards
  * the function may be called repeatedly until qlen reaches 0.
+ *
+ * The callback function may return -EINTR to signal that processing
+ * of netlink messages shall be interrupted. In this case the message
+ * currently being processed will NOT be requeued onto the receive
+ * queue.
  */
 void netlink_run_queue(struct sock *sk, unsigned int *qlen,
-		       int (*cb)(struct sk_buff *, struct nlmsghdr *, int *))
+		       int (*cb)(struct sk_buff *, struct nlmsghdr *))
 {
 	struct sk_buff *skb;
 
Index: net-2.6.22/net/netfilter/nf_conntrack_netlink.c
===================================================================
--- net-2.6.22.orig/net/netfilter/nf_conntrack_netlink.c	2007-03-21 16:07:09.000000000 +0100
+++ net-2.6.22/net/netfilter/nf_conntrack_netlink.c	2007-03-21 18:38:32.000000000 +0100
@@ -661,7 +661,7 @@ static const size_t cta_min[CTA_MAX] = {
 
 static int
 ctnetlink_del_conntrack(struct sock *ctnl, struct sk_buff *skb,
-			struct nlmsghdr *nlh, struct nfattr *cda[], int *errp)
+			struct nlmsghdr *nlh, struct nfattr *cda[])
 {
 	struct nf_conntrack_tuple_hash *h;
 	struct nf_conntrack_tuple tuple;
@@ -709,7 +709,7 @@ ctnetlink_del_conntrack(struct sock *ctn
 
 static int
 ctnetlink_get_conntrack(struct sock *ctnl, struct sk_buff *skb,
-			struct nlmsghdr *nlh, struct nfattr *cda[], int *errp)
+			struct nlmsghdr *nlh, struct nfattr *cda[])
 {
 	struct nf_conntrack_tuple_hash *h;
 	struct nf_conntrack_tuple tuple;
@@ -720,22 +720,15 @@ ctnetlink_get_conntrack(struct sock *ctn
 	int err = 0;
 
 	if (nlh->nlmsg_flags & NLM_F_DUMP) {
-		u32 rlen;
-
 #ifndef CONFIG_NF_CT_ACCT
 		if (NFNL_MSG_TYPE(nlh->nlmsg_type) == IPCTNL_MSG_CT_GET_CTRZERO)
 			return -ENOTSUPP;
 #endif
-		if ((*errp = netlink_dump_start(ctnl, skb, nlh,
-						ctnetlink_dump_table,
-						ctnetlink_done)) != 0)
-			return -EINVAL;
-
-		rlen = NLMSG_ALIGN(nlh->nlmsg_len);
-		if (rlen > skb->len)
-			rlen = skb->len;
-		skb_pull(skb, rlen);
-		return 0;
+		err = netlink_dump_start(ctnl, skb, nlh, ctnetlink_dump_table,
+					 ctnetlink_done);
+		if (err == 0)
+			err = -EINTR;
+		return err;
 	}
 
 	if (nfattr_bad_size(cda, CTA_MAX, cta_min))
@@ -1009,7 +1002,7 @@ err:
 
 static int
 ctnetlink_new_conntrack(struct sock *ctnl, struct sk_buff *skb,
-			struct nlmsghdr *nlh, struct nfattr *cda[], int *errp)
+			struct nlmsghdr *nlh, struct nfattr *cda[])
 {
 	struct nf_conntrack_tuple otuple, rtuple;
 	struct nf_conntrack_tuple_hash *h = NULL;
@@ -1260,7 +1253,7 @@ static const size_t cta_min_exp[CTA_EXPE
 
 static int
 ctnetlink_get_expect(struct sock *ctnl, struct sk_buff *skb,
-		     struct nlmsghdr *nlh, struct nfattr *cda[], int *errp)
+		     struct nlmsghdr *nlh, struct nfattr *cda[])
 {
 	struct nf_conntrack_tuple tuple;
 	struct nf_conntrack_expect *exp;
@@ -1273,17 +1266,12 @@ ctnetlink_get_expect(struct sock *ctnl, 
 		return -EINVAL;
 
 	if (nlh->nlmsg_flags & NLM_F_DUMP) {
-		u32 rlen;
-
-		if ((*errp = netlink_dump_start(ctnl, skb, nlh,
-						ctnetlink_exp_dump_table,
-						ctnetlink_done)) != 0)
-			return -EINVAL;
-		rlen = NLMSG_ALIGN(nlh->nlmsg_len);
-		if (rlen > skb->len)
-			rlen = skb->len;
-		skb_pull(skb, rlen);
-		return 0;
+		err = netlink_dump_start(ctnl, skb, nlh,
+					 ctnetlink_exp_dump_table,
+					 ctnetlink_done);
+		if (err == 0)
+			err = -EINTR;
+		return err;
 	}
 
 	if (cda[CTA_EXPECT_MASTER-1])
@@ -1330,7 +1318,7 @@ out:
 
 static int
 ctnetlink_del_expect(struct sock *ctnl, struct sk_buff *skb,
-		     struct nlmsghdr *nlh, struct nfattr *cda[], int *errp)
+		     struct nlmsghdr *nlh, struct nfattr *cda[])
 {
 	struct nf_conntrack_expect *exp, *tmp;
 	struct nf_conntrack_tuple tuple;
@@ -1464,7 +1452,7 @@ out:
 
 static int
 ctnetlink_new_expect(struct sock *ctnl, struct sk_buff *skb,
-		     struct nlmsghdr *nlh, struct nfattr *cda[], int *errp)
+		     struct nlmsghdr *nlh, struct nfattr *cda[])
 {
 	struct nf_conntrack_tuple tuple;
 	struct nf_conntrack_expect *exp;
Index: net-2.6.22/net/netfilter/nfnetlink_log.c
===================================================================
--- net-2.6.22.orig/net/netfilter/nfnetlink_log.c	2007-03-21 16:09:47.000000000 +0100
+++ net-2.6.22/net/netfilter/nfnetlink_log.c	2007-03-21 16:10:11.000000000 +0100
@@ -759,7 +759,7 @@ static struct notifier_block nfulnl_rtnl
 
 static int
 nfulnl_recv_unsupp(struct sock *ctnl, struct sk_buff *skb,
-		  struct nlmsghdr *nlh, struct nfattr *nfqa[], int *errp)
+		  struct nlmsghdr *nlh, struct nfattr *nfqa[])
 {
 	return -ENOTSUPP;
 }
@@ -797,7 +797,7 @@ static const int nfula_cfg_min[NFULA_CFG
 
 static int
 nfulnl_recv_config(struct sock *ctnl, struct sk_buff *skb,
-		   struct nlmsghdr *nlh, struct nfattr *nfula[], int *errp)
+		   struct nlmsghdr *nlh, struct nfattr *nfula[])
 {
 	struct nfgenmsg *nfmsg = NLMSG_DATA(nlh);
 	u_int16_t group_num = ntohs(nfmsg->res_id);
Index: net-2.6.22/net/netfilter/nfnetlink_queue.c
===================================================================
--- net-2.6.22.orig/net/netfilter/nfnetlink_queue.c	2007-03-21 16:10:21.000000000 +0100
+++ net-2.6.22/net/netfilter/nfnetlink_queue.c	2007-03-21 16:11:55.000000000 +0100
@@ -783,7 +783,7 @@ static const int nfqa_verdict_min[NFQA_M
 
 static int
 nfqnl_recv_verdict(struct sock *ctnl, struct sk_buff *skb,
-		   struct nlmsghdr *nlh, struct nfattr *nfqa[], int *errp)
+		   struct nlmsghdr *nlh, struct nfattr *nfqa[])
 {
 	struct nfgenmsg *nfmsg = NLMSG_DATA(nlh);
 	u_int16_t queue_num = ntohs(nfmsg->res_id);
@@ -848,7 +848,7 @@ err_out_put:
 
 static int
 nfqnl_recv_unsupp(struct sock *ctnl, struct sk_buff *skb,
-		  struct nlmsghdr *nlh, struct nfattr *nfqa[], int *errp)
+		  struct nlmsghdr *nlh, struct nfattr *nfqa[])
 {
 	return -ENOTSUPP;
 }
@@ -865,7 +865,7 @@ static struct nf_queue_handler nfqh = {
 
 static int
 nfqnl_recv_config(struct sock *ctnl, struct sk_buff *skb,
-		  struct nlmsghdr *nlh, struct nfattr *nfqa[], int *errp)
+		  struct nlmsghdr *nlh, struct nfattr *nfqa[])
 {
 	struct nfgenmsg *nfmsg = NLMSG_DATA(nlh);
 	u_int16_t queue_num = ntohs(nfmsg->res_id);
Index: net-2.6.22/include/linux/netfilter/nfnetlink.h
===================================================================
--- net-2.6.22.orig/include/linux/netfilter/nfnetlink.h	2007-03-21 16:13:31.000000000 +0100
+++ net-2.6.22/include/linux/netfilter/nfnetlink.h	2007-03-21 16:13:41.000000000 +0100
@@ -111,7 +111,7 @@ struct nfgenmsg {
 struct nfnl_callback
 {
 	int (*call)(struct sock *nl, struct sk_buff *skb, 
-		struct nlmsghdr *nlh, struct nfattr *cda[], int *errp);
+		struct nlmsghdr *nlh, struct nfattr *cda[]);
 	u_int16_t attr_count;	/* number of nfattr's */
 };
 

--

[PATCH 2/3] [IPv4] diag: Use netlink_run_queue() to process the receive queue

[Thomas Graf]

[-- Attachment #1: inet_diag_queue_run --]
[-- Type: text/plain, Size: 3041 bytes --]

Makes use of netlink_run_queue() to process the receive queue and
converts inet_diag_rcv_msg() to use the type safe netlink interface.

Signed-off-by: Thomas Graf <tgraf@suug.ch>

Index: net-2.6.22/net/ipv4/inet_diag.c
===================================================================
--- net-2.6.22.orig/net/ipv4/inet_diag.c	2007-03-21 18:40:29.000000000 +0100
+++ net-2.6.22/net/ipv4/inet_diag.c	2007-03-22 00:08:05.000000000 +0100
@@ -806,68 +806,48 @@ done:
 	return skb->len;
 }
 
-static inline int inet_diag_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
+static int inet_diag_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 {
-	if (!(nlh->nlmsg_flags&NLM_F_REQUEST))
-		return 0;
+	int hdrlen = sizeof(struct inet_diag_req);
 
-	if (nlh->nlmsg_type >= INET_DIAG_GETSOCK_MAX)
-		goto err_inval;
+	if (nlh->nlmsg_type >= INET_DIAG_GETSOCK_MAX ||
+	    nlmsg_len(nlh) < hdrlen)
+		return -EINVAL;
 
 	if (inet_diag_table[nlh->nlmsg_type] == NULL)
 		return -ENOENT;
 
-	if (NLMSG_LENGTH(sizeof(struct inet_diag_req)) > skb->len)
-		goto err_inval;
-
-	if (nlh->nlmsg_flags&NLM_F_DUMP) {
-		if (nlh->nlmsg_len >
-		    (4 + NLMSG_SPACE(sizeof(struct inet_diag_req)))) {
-			struct rtattr *rta = (void *)(NLMSG_DATA(nlh) +
-						 sizeof(struct inet_diag_req));
-			if (rta->rta_type != INET_DIAG_REQ_BYTECODE ||
-			    rta->rta_len < 8 ||
-			    rta->rta_len >
-			    (nlh->nlmsg_len -
-			     NLMSG_SPACE(sizeof(struct inet_diag_req))))
-				goto err_inval;
-			if (inet_diag_bc_audit(RTA_DATA(rta), RTA_PAYLOAD(rta)))
-				goto err_inval;
-		}
-		return netlink_dump_start(idiagnl, skb, nlh,
-					  inet_diag_dump, NULL);
-	} else
-		return inet_diag_get_exact(skb, nlh);
-
-err_inval:
-	return -EINVAL;
-}
+	if (nlh->nlmsg_flags & NLM_F_DUMP) {
+		int err;
 
+		if (nlmsg_attrlen(nlh, hdrlen)) {
+			struct nlattr *attr;
 
-static inline void inet_diag_rcv_skb(struct sk_buff *skb)
-{
-	if (skb->len >= NLMSG_SPACE(0)) {
-		int err;
-		struct nlmsghdr *nlh = nlmsg_hdr(skb);
+			attr = nlmsg_find_attr(nlh, hdrlen,
+					       INET_DIAG_REQ_BYTECODE);
+			if (attr == NULL ||
+			    nla_len(attr) < sizeof(struct inet_diag_bc_op) ||
+			    inet_diag_bc_audit(nla_data(attr), nla_len(attr)))
+				return -EINVAL;
+		}
 
-		if (nlh->nlmsg_len < sizeof(*nlh) ||
-		    skb->len < nlh->nlmsg_len)
-			return;
-		err = inet_diag_rcv_msg(skb, nlh);
-		if (err || nlh->nlmsg_flags & NLM_F_ACK)
-			netlink_ack(skb, nlh, err);
+		err = netlink_dump_start(idiagnl, skb, nlh,
+					 inet_diag_dump, NULL);
+		if (err == 0)
+			err = -EINTR;
+		return err;
 	}
+
+	return inet_diag_get_exact(skb, nlh);
 }
 
 static void inet_diag_rcv(struct sock *sk, int len)
 {
-	struct sk_buff *skb;
-	unsigned int qlen = skb_queue_len(&sk->sk_receive_queue);
+	unsigned int qlen = 0;
 
-	while (qlen-- && (skb = skb_dequeue(&sk->sk_receive_queue))) {
-		inet_diag_rcv_skb(skb);
-		kfree_skb(skb);
-	}
+	do {
+		netlink_run_queue(sk, &qlen, &inet_diag_rcv_msg);
+	} while (qlen);
 }
 
 static DEFINE_SPINLOCK(inet_diag_register_lock);

--

[PATCH 3/3] [NETLINK]: Directly return -EINTR from netlink_dump_start()

[Thomas Graf]

[-- Attachment #1: netlink_dump_start_retval --]
[-- Type: text/plain, Size: 5101 bytes --]

Now that all users of netlink_dump_start() use netlink_run_queue()
to process the receive queue, it is possible to return -EINTR from
netlink_dump_start() directly, therefore simplying the callers.

Signed-off-by: Thomas Graf <tgraf@suug.ch>

Index: net-2.6.22/net/core/rtnetlink.c
===================================================================
--- net-2.6.22.orig/net/core/rtnetlink.c	2007-03-21 18:38:32.000000000 +0100
+++ net-2.6.22/net/core/rtnetlink.c	2007-03-22 00:09:35.000000000 +0100
@@ -858,7 +858,6 @@ static int rtnetlink_rcv_msg(struct sk_b
 	int min_len;
 	int family;
 	int type;
-	int err;
 
 	type = nlh->nlmsg_type;
 	if (type > RTM_MAX)
@@ -887,10 +886,7 @@ static int rtnetlink_rcv_msg(struct sk_b
 		if (dumpit == NULL)
 			return -EINVAL;
 
-		err = netlink_dump_start(rtnl, skb, nlh, dumpit, NULL);
-		if (err == 0)
-			err = -EINTR;
-		return err;
+		return netlink_dump_start(rtnl, skb, nlh, dumpit, NULL);
 	}
 
 	memset(rta_buf, 0, (rtattr_max * sizeof(struct rtattr *)));
Index: net-2.6.22/net/ipv4/inet_diag.c
===================================================================
--- net-2.6.22.orig/net/ipv4/inet_diag.c	2007-03-22 00:08:05.000000000 +0100
+++ net-2.6.22/net/ipv4/inet_diag.c	2007-03-22 00:10:05.000000000 +0100
@@ -818,8 +818,6 @@ static int inet_diag_rcv_msg(struct sk_b
 		return -ENOENT;
 
 	if (nlh->nlmsg_flags & NLM_F_DUMP) {
-		int err;
-
 		if (nlmsg_attrlen(nlh, hdrlen)) {
 			struct nlattr *attr;
 
@@ -831,11 +829,8 @@ static int inet_diag_rcv_msg(struct sk_b
 				return -EINVAL;
 		}
 
-		err = netlink_dump_start(idiagnl, skb, nlh,
-					 inet_diag_dump, NULL);
-		if (err == 0)
-			err = -EINTR;
-		return err;
+		return netlink_dump_start(idiagnl, skb, nlh,
+					  inet_diag_dump, NULL);
 	}
 
 	return inet_diag_get_exact(skb, nlh);
Index: net-2.6.22/net/netfilter/nf_conntrack_netlink.c
===================================================================
--- net-2.6.22.orig/net/netfilter/nf_conntrack_netlink.c	2007-03-21 18:38:32.000000000 +0100
+++ net-2.6.22/net/netfilter/nf_conntrack_netlink.c	2007-03-22 00:08:25.000000000 +0100
@@ -724,11 +724,8 @@ ctnetlink_get_conntrack(struct sock *ctn
 		if (NFNL_MSG_TYPE(nlh->nlmsg_type) == IPCTNL_MSG_CT_GET_CTRZERO)
 			return -ENOTSUPP;
 #endif
-		err = netlink_dump_start(ctnl, skb, nlh, ctnetlink_dump_table,
-					 ctnetlink_done);
-		if (err == 0)
-			err = -EINTR;
-		return err;
+		return netlink_dump_start(ctnl, skb, nlh, ctnetlink_dump_table,
+					  ctnetlink_done);
 	}
 
 	if (nfattr_bad_size(cda, CTA_MAX, cta_min))
@@ -1266,12 +1263,9 @@ ctnetlink_get_expect(struct sock *ctnl, 
 		return -EINVAL;
 
 	if (nlh->nlmsg_flags & NLM_F_DUMP) {
-		err = netlink_dump_start(ctnl, skb, nlh,
-					 ctnetlink_exp_dump_table,
-					 ctnetlink_done);
-		if (err == 0)
-			err = -EINTR;
-		return err;
+		return netlink_dump_start(ctnl, skb, nlh,
+					  ctnetlink_exp_dump_table,
+					  ctnetlink_done);
 	}
 
 	if (cda[CTA_EXPECT_MASTER-1])
Index: net-2.6.22/net/netlink/af_netlink.c
===================================================================
--- net-2.6.22.orig/net/netlink/af_netlink.c	2007-03-22 00:02:36.000000000 +0100
+++ net-2.6.22/net/netlink/af_netlink.c	2007-03-22 00:08:25.000000000 +0100
@@ -1426,7 +1426,12 @@ int netlink_dump_start(struct sock *ssk,
 
 	netlink_dump(sk);
 	sock_put(sk);
-	return 0;
+
+	/* We successfully started a dump, by returning -EINTR we
+	 * signal the queue mangement to interrupt processing of
+	 * any netlink messages so userspace gets a chance to read
+	 * the results. */
+	return -EINTR;
 }
 
 void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)
Index: net-2.6.22/net/netlink/genetlink.c
===================================================================
--- net-2.6.22.orig/net/netlink/genetlink.c	2007-03-21 18:38:32.000000000 +0100
+++ net-2.6.22/net/netlink/genetlink.c	2007-03-22 00:08:25.000000000 +0100
@@ -323,11 +323,8 @@ static int genl_rcv_msg(struct sk_buff *
 		if (ops->dumpit == NULL)
 			return -EOPNOTSUPP;
 
-		err = netlink_dump_start(genl_sock, skb, nlh,
-					 ops->dumpit, ops->done);
-		if (err == 0)
-			err = -EINTR;
-		return err;
+		return netlink_dump_start(genl_sock, skb, nlh,
+					  ops->dumpit, ops->done);
 	}
 
 	if (ops->doit == NULL)
Index: net-2.6.22/net/xfrm/xfrm_user.c
===================================================================
--- net-2.6.22.orig/net/xfrm/xfrm_user.c	2007-03-21 18:38:32.000000000 +0100
+++ net-2.6.22/net/xfrm/xfrm_user.c	2007-03-22 00:10:29.000000000 +0100
@@ -1857,7 +1857,7 @@ static int xfrm_user_rcv_msg(struct sk_b
 {
 	struct rtattr *xfrma[XFRMA_MAX];
 	struct xfrm_link *link;
-	int type, min_len, err;
+	int type, min_len;
 
 	type = nlh->nlmsg_type;
 	if (type > XFRM_MSG_MAX)
@@ -1876,10 +1876,7 @@ static int xfrm_user_rcv_msg(struct sk_b
 		if (link->dump == NULL)
 			return -EINVAL;
 
-		err = netlink_dump_start(xfrm_nl, skb, nlh, link->dump, NULL);
-		if (err == 0)
-			err = -EINTR;
-		return err;
+		return netlink_dump_start(xfrm_nl, skb, nlh, link->dump, NULL);
 	}
 
 	memset(xfrma, 0, sizeof(xfrma));

--

Re: [PATCH 0/3] [PATCHSET] netlink error management

[David Miller]

From: Thomas Graf <tgraf@suug.ch>
Date: Thu, 22 Mar 2007 00:18:01 +0100

> This series of patches simplifies the error management and
> signalization of dump starts of netlink_run_queue() message
> handlers. It touches a fair bit of nfnetlink code as the
> error pointer has been passed on to subsystems.

Thomas can you respin these patches?  They no longer apply
now that I put your other rtnl_link bits into net-2.6.22

Thanks.

Re: [PATCH 0/3] [PATCHSET] netlink error management

[Thomas Graf]

* David Miller <davem@davemloft.net> 2007-03-22 12:23
> From: Thomas Graf <tgraf@suug.ch>
> Date: Thu, 22 Mar 2007 00:18:01 +0100
> 
> > This series of patches simplifies the error management and
> > signalization of dump starts of netlink_run_queue() message
> > handlers. It touches a fair bit of nfnetlink code as the
> > error pointer has been passed on to subsystems.
> 
> Thomas can you respin these patches?  They no longer apply
> now that I put your other rtnl_link bits into net-2.6.22

I guess I've posted too many patches series, the patches should
still apply, at least it works in my quilt tree, but depend on
others. The series I've posted in the correct order are:

[RESEND] rtnetlink message handler registration interface
  already applied
 
[RESEND] [NET] rules: Unified rules dumping
  already applied

[PATCH 0/5] [PATCHSET] Netlink Patches
  even though there have been objects because of nfnetlink
  at first, the patches can go in as-is

[NETFILTER] nfnetlink: netlink_run_queue() already checks
                       for NLM_F_REQUEST

[PATCH 0/3] [PATCHSET] netlink error management

Re: [PATCH 0/3] [PATCHSET] netlink error management

[David Miller]

From: Thomas Graf <tgraf@suug.ch>
Date: Thu, 22 Mar 2007 20:57:54 +0100

> * David Miller <davem@davemloft.net> 2007-03-22 12:23
> > From: Thomas Graf <tgraf@suug.ch>
> > Date: Thu, 22 Mar 2007 00:18:01 +0100
> > 
> > > This series of patches simplifies the error management and
> > > signalization of dump starts of netlink_run_queue() message
> > > handlers. It touches a fair bit of nfnetlink code as the
> > > error pointer has been passed on to subsystems.
> > 
> > Thomas can you respin these patches?  They no longer apply
> > now that I put your other rtnl_link bits into net-2.6.22
> 
> I guess I've posted too many patches series, the patches should
> still apply, at least it works in my quilt tree, but depend on
> others. The series I've posted in the correct order are:

It doesn't, that's why I asked you to respin.

Perhaps "patch" would allow them with some fuzz, but git
definitely doesn't want to apply it.