Set the correct RTNL family for multicast netconf messages

net/ipv4/devinet.c +10 -1

index dfc39d4..695858b 100644
@@ -1705,7 +1705,16 @@ static int inet_netconf_fill_devconf(struct sk_buff *skb, int ifindex,
 		return -EMSGSIZE;
 
 	ncm = nlmsg_data(nlh);
-	ncm->ncm_family = AF_INET;
+
+	switch (type) {
+		case NETCONFA_MC_FORWARDING:
+			ncm->ncm_family = RTNL_FAMILY_IPMR;
+			break;
+
+		default:
+			ncm->ncm_family = AF_INET;
+			break;
+	}
 
 	if (nla_put_s32(skb, NETCONFA_IFINDEX, ifindex) < 0)
 		goto nla_put_failure;

net/ipv6/addrconf.c +1 -1

index 4ab4c38..a177da4 100644
@@ -492,7 +492,16 @@ static int inet6_netconf_fill_devconf(struct sk_buff *skb, int ifindex,
 		return -EMSGSIZE;
 
 	ncm = nlmsg_data(nlh);
-	ncm->ncm_family = AF_INET6;
+

Quoted 38 lines · Sven-Thorsten Dietrich

net/ipv4/devinet.c +10 -1

index dfc39d4..695858b 100644
@@ -1705,7 +1705,16 @@ static int inet_netconf_fill_devconf(struct sk_buff *skb, int ifindex,
 		return -EMSGSIZE;
 
 	ncm = nlmsg_data(nlh);
-	ncm->ncm_family = AF_INET;
+
+	switch (type) {
+		case NETCONFA_MC_FORWARDING:
+			ncm->ncm_family = RTNL_FAMILY_IPMR;
+			break;
+
+		default:
+			ncm->ncm_family = AF_INET;
+			break;
+	}
 
 	if (nla_put_s32(skb, NETCONFA_IFINDEX, ifindex) < 0)
 		goto nla_put_failure;

net/ipv6/addrconf.c +7 -1

index 4ab4c38..a177da4 100644
@@ -492,7 +492,16 @@ static int inet6_netconf_fill_devconf(struct sk_buff *skb, int ifindex,
 		return -EMSGSIZE;
 
 	ncm = nlmsg_data(nlh);
-	ncm->ncm_family = AF_INET6;
+
+	switch (type) {
+		case NETCONFA_MC_FORWARDING:
+			ncm->ncm_family = RTNL_FAMILY_IP6MR;
+			break;
+
+		default:

net/ipv6/addrconf.c static int inet6_netconf_fill_devconf(struct sk_buff *skb, int ifindex, · line 505

Quoted 4 lines

net/ipv6/addrconf.c +3 -0

+			ncm->ncm_family = AF_INET6;
+			break;
+	}
 

Hm, are you sure? NETCONFA_MC_FORWARDING is of type RTM_NEWNETCONF and expects ncm_family to be either AF_INET or AF_INET6 (at least in iproute2/ipmonitor.c).

Quoted 4 lines · On Fri, 28 Jun 2013 03:23:07 +0200 Hannes Frederic Sowa…

Hm, are you sure? NETCONFA_MC_FORWARDING is of type RTM_NEWNETCONF and expects ncm_family to be either AF_INET or AF_INET6 (at least in iproute2/ipmonitor.c).

I agree with Sven on this, looks like the recent addition of netconf configuration to netlink didn't embrace how multicast is handled in kernel.

Multicast forwarding is a routing related configuration value. All the multicast routing events come in as special family RTNL_FAMILY_IPMR (see net/ipv4/ipmr.c function ipmr_fill_route). I would expect that multicast routing daemons would like to be able to use special family to listen for all multicast related changes (and not see non-multicast events).

Minor nit: the patch is formatted incorrectly (case should line up with switch).

Quoted 17 lines · Stephen Hemminger

Quoted 4 lines · On Fri, 28 Jun 2013 03:23:07 +0200 Hannes Frederic Sowa…

Hm, are you sure? NETCONFA_MC_FORWARDING is of type RTM_NEWNETCONF and expects ncm_family to be either AF_INET or AF_INET6 (at least in iproute2/ipmonitor.c).

I agree with Sven on this, looks like the recent addition of netconf configuration to netlink didn't embrace how multicast is handled in kernel.

Multicast forwarding is a routing related configuration value. All the multicast routing events come in as special family RTNL_FAMILY_IPMR (see net/ipv4/ipmr.c function ipmr_fill_route). I would expect that multicast routing daemons would like to be able to use special family to listen for all multicast related changes (and not see non-multicast events).

Quoted 1 line

Minor nit: the patch is formatted incorrectly (case should line up with switch).

Yes, this seems reasonable but would need a small update to ipnetconf.c, too.

There may be other cases that require a special case, so I chose the switch approach.

Please note, that all other messages from ipmr[6].c correctly set the family, while these do not.

Thanks

Sven

Subject: Set correct RTNL family for multicast netconf messages
From: Sven-Thorsten Dietrich [email protected] Thu Jun 27 16:40:17 2013 -0700
Date: Thu Jun 27 16:40:17 2013 -0700:

net/ipv4/devinet.c +10 -1

index dfc39d4..695858b 100644
@@ -1705,7 +1705,16 @@ static int inet_netconf_fill_devconf(struct sk_buff *skb, int ifindex,
 		return -EMSGSIZE;
 
 	ncm = nlmsg_data(nlh);
-	ncm->ncm_family = AF_INET;
+
+	switch (type) {
+		case NETCONFA_MC_FORWARDING:
+			ncm->ncm_family = RTNL_FAMILY_IPMR;
+			break;
+
+		default:
+			ncm->ncm_family = AF_INET;
+			break;
+	}
 
 	if (nla_put_s32(skb, NETCONFA_IFINDEX, ifindex) < 0)
 		goto nla_put_failure;

net/ipv6/addrconf.c +3 -1

index 4ab4c38..a177da4 100644
@@ -492,7 +492,16 @@ static int inet6_netconf_fill_devconf(struct sk_buff *skb, int ifindex,
 		return -EMSGSIZE;
 
 	ncm = nlmsg_data(nlh);
-	ncm->ncm_family = AF_INET6;
+
+	switch (type) {
+		case NETCONFA_MC_FORWARDING:

Quoted 50 lines · On Thu, 27 Jun 2013 16:44:47 -0700 Sven-Thorsten Dietrich <[email protected]>…

There may be other cases that require a special case, so I chose the switch approach.

Please note, that all other messages from ipmr[6].c correctly set the family, while these do not.

Thanks

Sven

Subject: Set correct RTNL family for multicast netconf messages
From: Sven-Thorsten Dietrich [email protected] Thu Jun 27 16:40:17 2013 -0700
Date: Thu Jun 27 16:40:17 2013 -0700:

net/ipv4/devinet.c +10 -1

index dfc39d4..695858b 100644
@@ -1705,7 +1705,16 @@ static int inet_netconf_fill_devconf(struct sk_buff *skb, int ifindex,
  		return -EMSGSIZE;
 
  	ncm = nlmsg_data(nlh);
-	ncm->ncm_family = AF_INET;
+
+	switch (type) {
+		case NETCONFA_MC_FORWARDING:
+			ncm->ncm_family = RTNL_FAMILY_IPMR;
+			break;
+
+		default:
+			ncm->ncm_family = AF_INET;
+			break;
+	}
 
  	if (nla_put_s32(skb, NETCONFA_IFINDEX, ifindex) < 0)
  		goto nla_put_failure;

net/ipv6/addrconf.c +3 -1

index 4ab4c38..a177da4 100644
@@ -492,7 +492,16 @@ static int inet6_netconf_fill_devconf(struct sk_buff *skb, int ifindex,
  		return -EMSGSIZE;
 
  	ncm = nlmsg_data(nlh);
-	ncm->ncm_family = AF_INET6;
+
+	switch (type) {
+		case NETCONFA_MC_FORWARDING:

net/ipv6/addrconf.c static int inet6_netconf_fill_devconf(struct sk_buff *skb, int ifindex, · line 507

Quoted 10 lines

net/ipv6/addrconf.c +7 -0

+			ncm->ncm_family = RTNL_FAMILY_IP6MR;
+			break;
+
+		default:
+			ncm->ncm_family = AF_INET6;
+			break;
+	}
 
  	if (nla_put_s32(skb, NETCONFA_IFINDEX, ifindex) < 0)
  		goto nla_put_failure;

Found another issue that needs some thought.
If type == ALL, in that case the family comes up as AF_INET. That means that if application is doing a request to get netconf it will receive a different answer than if it is montoring for netconf changes.

One way to solve would be to split fill_devconf into two parts, one for unicast, and one for multicast.

Revised version of Sven's patch. The idea is that multicast forwarding should be under the multicast address family like other multicast netlink messages.

This version generates each family under separate headers when doing dump all.

Compile tested only, this is to show some of the issues that need to be covered.

Signed-off-by Stephen Hemminger <[email protected]>

net/ipv4/devinet.c +9 -3

@@ -1685,6 +1685,11 @@ static int inet_netconf_msgsize_devconf(
  		size += nla_total_size(4);
  	if (type == -1 || type == NETCONFA_RP_FILTER)
  		size += nla_total_size(4);
+
+	/* additional header for MC family */
+	if (type == -1)
+		size += NLMSG_ALIGN(sizeof(struct netconfmsg))
+		   + nla_total_size(4);
  	if (type == -1 || type == NETCONFA_MC_FORWARDING)
  		size += nla_total_size(4);
 

@@ -1694,7 +1699,7 @@ static int inet_netconf_msgsize_devconf(
  static int inet_netconf_fill_devconf(struct sk_buff *skb, int ifindex,
  				     struct ipv4_devconf *devconf, u32 portid,
  				     u32 seq, int event, unsigned int flags,
-				     int type)
+				     u8 family, int type)
  {
  	struct nlmsghdr  *nlh;
  	struct netconfmsg *ncm;

@@ -1705,21 +1710,24 @@ static int inet_netconf_fill_devconf(str
  		return -EMSGSIZE;
 
  	ncm = nlmsg_data(nlh);
-	ncm->ncm_family = AF_INET;
+	ncm->ncm_family = family;
 
  	if (nla_put_s32(skb, NETCONFA_IFINDEX, ifindex) < 0)
  		goto nla_put_failure;
 
  	/* type -1 is used for ALL */
-	if ((type == -1 || type == NETCONFA_FORWARDING) &&
+	if (((type == -1 && family == AF_INET) ||
+	     type == NETCONFA_FORWARDING)  &&
  	    nla_put_s32(skb, NETCONFA_FORWARDING,

net/ipv4/devinet.c +8 -2

+	     type == NETCONFA_MC_FORWARDING) &&
  	    nla_put_s32(skb, NETCONFA_MC_FORWARDING,
  			IPV4_DEVCONF(*devconf, MC_FORWARDING)) < 0)
  		goto nla_put_failure;

@@ -1737,12 +1745,17 @@ void inet_netconf_notify_devconf(struct
  	struct sk_buff *skb;
  	int err = -ENOBUFS;
 
+	BUG_ON(type == -1); /* ALL is not valid for notification */
+
  	skb = nlmsg_new(inet_netconf_msgsize_devconf(type), GFP_ATOMIC);
  	if (skb == NULL)
  		goto errout;
 
  	err = inet_netconf_fill_devconf(skb, ifindex, devconf, 0, 0,
-					RTM_NEWNETCONF, 0, type);
+					RTM_NEWNETCONF, 0,
+					(type == NETCONFA_MC_FORWARDING) ?
+					RTNL_FAMILY_IPMR : AF_INET,
+					type);
  	if (err < 0) {
  		/* -EMSGSIZE implies BUG in inet_netconf_msgsize_devconf() */
  		WARN_ON(err == -EMSGSIZE);

@@ -1811,13 +1824,23 @@ static int inet_netconf_get_devconf(stru
  	err = inet_netconf_fill_devconf(skb, ifindex, devconf,
  					NETLINK_CB(in_skb).portid,
  					nlh->nlmsg_seq, RTM_NEWNETCONF, 0,
-					-1);
+					AF_INET, -1);
  	if (err < 0) {
  		/* -EMSGSIZE implies BUG in inet_netconf_msgsize_devconf() */
  		WARN_ON(err == -EMSGSIZE);
  		kfree_skb(skb);
  		goto errout;
  	}

net/ipv4/devinet.c +35 -6

  	err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
  errout:
  	return err;

@@ -1855,10 +1878,23 @@ static int inet_netconf_dump_devconf(str
  						      cb->nlh->nlmsg_seq,
  						      RTM_NEWNETCONF,
  						      NLM_F_MULTI,
+						      AF_INET,
+						      -1) <= 0) {
+				rcu_read_unlock();
+				goto done;
+			}
+			if (inet_netconf_fill_devconf(skb, dev->ifindex,
+						      &in_dev->cnf,
+						      NETLINK_CB(cb->skb).portid,
+						      cb->nlh->nlmsg_seq,
+						      RTM_NEWNETCONF,
+						      NLM_F_MULTI,
+						      RTNL_FAMILY_IPMR,
  						      -1) <= 0) {
  				rcu_read_unlock();
  				goto done;
  			}
+
  			nl_dump_check_consistent(cb, nlmsg_hdr(skb));
  cont:
  			idx++;

@@ -1871,10 +1907,18 @@ cont:
  					      NETLINK_CB(cb->skb).portid,
  					      cb->nlh->nlmsg_seq,
  					      RTM_NEWNETCONF, NLM_F_MULTI,
-					      -1) <= 0)
+					      AF_INET, -1) <= 0)
+			goto done;
+
+		if (inet_netconf_fill_devconf(skb, NETCONFA_IFINDEX_ALL,
+					      net->ipv4.devconf_all,
+					      NETLINK_CB(cb->skb).portid,
+					      cb->nlh->nlmsg_seq,
+					      RTM_NEWNETCONF, NLM_F_MULTI,
+					      RTNL_FAMILY_IPMR, -1) <= 0)
  			goto done;
-		else
-			h++;
+
+		h++;
  	}
  	if (h == NETDEV_HASHENTRIES + 1) {
  		if (inet_netconf_fill_devconf(skb, NETCONFA_IFINDEX_DEFAULT,

@@ -1882,10 +1926,18 @@ cont:
  					      NETLINK_CB(cb->skb).portid,
  					      cb->nlh->nlmsg_seq,
  					      RTM_NEWNETCONF, NLM_F_MULTI,
-					      -1) <= 0)
+					      AF_INET, -1) <= 0)
  			goto done;
-		else
-			h++;
+
+		if (inet_netconf_fill_devconf(skb, NETCONFA_IFINDEX_DEFAULT,
+					      net->ipv4.devconf_dflt,
+					      NETLINK_CB(cb->skb).portid,
+					      cb->nlh->nlmsg_seq,
+					      RTM_NEWNETCONF, NLM_F_MULTI,
+					      RTNL_FAMILY_IPMR, -1) <= 0)
+			goto done;
+
+		h++;
  	}
  done:
  	cb->args[0] = h;

net/ipv6/addrconf.c +61 -10

@@ -471,6 +471,9 @@ static int inet6_netconf_msgsize_devconf
  	if (type == -1 || type == NETCONFA_FORWARDING)
  		size += nla_total_size(4);
  #ifdef CONFIG_IPV6_MROUTE
+	if (type == -1)
+		size += NLMSG_ALIGN(sizeof(struct netconfmsg))
+			+ nla_total_size(4);
  	if (type == -1 || type == NETCONFA_MC_FORWARDING)
  		size += nla_total_size(4);
  #endif

@@ -481,7 +484,7 @@ static int inet6_netconf_msgsize_devconf
  static int inet6_netconf_fill_devconf(struct sk_buff *skb, int ifindex,
  				      struct ipv6_devconf *devconf, u32 portid,
  				      u32 seq, int event, unsigned int flags,
-				      int type)
+				      u8 family, int type)
  {
  	struct nlmsghdr  *nlh;
  	struct netconfmsg *ncm;

@@ -492,17 +495,19 @@ static int inet6_netconf_fill_devconf(st
  		return -EMSGSIZE;
 
  	ncm = nlmsg_data(nlh);
-	ncm->ncm_family = AF_INET6;
+	ncm->ncm_family = family;
 
  	if (nla_put_s32(skb, NETCONFA_IFINDEX, ifindex) < 0)
  		goto nla_put_failure;
 
  	/* type -1 is used for ALL */
-	if ((type == -1 || type == NETCONFA_FORWARDING) &&
+	if (((type == -1 && family == AF_INET6) ||
+	     type == NETCONFA_FORWARDING) &&
  	    nla_put_s32(skb, NETCONFA_FORWARDING, devconf->forwarding) < 0)
  		goto nla_put_failure;
  #ifdef CONFIG_IPV6_MROUTE
-	if ((type == -1 || type == NETCONFA_MC_FORWARDING) &&
+	if (((type == -1 && family == RTNL_FAMILY_IP6MR) ||
+	     type == NETCONFA_MC_FORWARDING) &&
  	    nla_put_s32(skb, NETCONFA_MC_FORWARDING,
  			devconf->mc_forwarding) < 0)
  		goto nla_put_failure;

@@ -520,12 +525,23 @@ void inet6_netconf_notify_devconf(struct
  	struct sk_buff *skb;
  	int err = -ENOBUFS;
 
+	BUG_ON(type == -1);
+
  	skb = nlmsg_new(inet6_netconf_msgsize_devconf(type), GFP_ATOMIC);
  	if (skb == NULL)
  		goto errout;
 
+#ifdef CONFIG_IPV6_MROUTE
+	if (type == NETCONFA_MC_FORWARDING)
+		err = inet6_netconf_fill_devconf(skb, ifindex, devconf, 0, 0,
+						 RTM_NEWNETCONF, 0,
+						 RTNL_FAMILY_IP6MR, type);
+	else
+#endif
  	err = inet6_netconf_fill_devconf(skb, ifindex, devconf, 0, 0,
-					 RTM_NEWNETCONF, 0, type);
+					 RTM_NEWNETCONF, 0,
+					 AF_INET6, type);
+#endif
  	if (err < 0) {
  		/* -EMSGSIZE implies BUG in inet6_netconf_msgsize_devconf() */
  		WARN_ON(err == -EMSGSIZE);

@@ -592,13 +608,25 @@ static int inet6_netconf_get_devconf(str
  	err = inet6_netconf_fill_devconf(skb, ifindex, devconf,
  					 NETLINK_CB(in_skb).portid,
  					 nlh->nlmsg_seq, RTM_NEWNETCONF, 0,
-					 -1);
+					 AF_INET6, -1);
+	if (err < 0) {
+		/* -EMSGSIZE implies BUG in inet6_netconf_msgsize_devconf() */
+		WARN_ON(err == -EMSGSIZE);
+		kfree_skb(skb);
+		goto errout;
+	}
+#ifdef CONFIG_IPV6_MROUTE
+	err = inet6_netconf_fill_devconf(skb, ifindex, devconf,
+					 NETLINK_CB(in_skb).portid,
+					 nlh->nlmsg_seq, RTM_NEWNETCONF, 0,
+					 RTNL_FAMILY_IP6MR, -1);
  	if (err < 0) {
  		/* -EMSGSIZE implies BUG in inet6_netconf_msgsize_devconf() */
  		WARN_ON(err == -EMSGSIZE);
  		kfree_skb(skb);
  		goto errout;
  	}
+#endif
  	err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
  errout:
  	return err;

@@ -636,10 +664,23 @@ static int inet6_netconf_dump_devconf(st
  						       cb->nlh->nlmsg_seq,
  						       RTM_NEWNETCONF,
  						       NLM_F_MULTI,
+						       AF_INET6, -1) <= 0) {
+				rcu_read_unlock();
+				goto done;
+			}
+#ifdef CONFIG_IPV6_MROUTE
+			if (inet6_netconf_fill_devconf(skb, dev->ifindex,
+						       &idev->cnf,
+						       NETLINK_CB(cb->skb).portid,
+						       cb->nlh->nlmsg_seq,
+						       RTM_NEWNETCONF,
+						       NLM_F_MULTI,
+						       RTNL_FAMILY_IP6MR,
  						       -1) <= 0) {
  				rcu_read_unlock();
  				goto done;
  			}
+#endif
  			nl_dump_check_consistent(cb, nlmsg_hdr(skb));
  cont:
  			idx++;

@@ -652,10 +693,18 @@ cont:
  					       NETLINK_CB(cb->skb).portid,
  					       cb->nlh->nlmsg_seq,
  					       RTM_NEWNETCONF, NLM_F_MULTI,
-					       -1) <= 0)
+					       AF_INET6, -1) <= 0)
  			goto done;
-		else
-			h++;
+#ifdef CONFIG_IPV6_MROUTE
+		if (inet6_netconf_fill_devconf(skb, NETCONFA_IFINDEX_ALL,
+					       net->ipv6.devconf_all,
+					       NETLINK_CB(cb->skb).portid,
+					       cb->nlh->nlmsg_seq,
+					       RTM_NEWNETCONF, NLM_F_MULTI,
+					       RTNL_FAMILY_IP6MR, -1) <= 0)
+			goto done;
+#endif
+		h++;
  	}
  	if (h == NETDEV_HASHENTRIES + 1) {
  		if (inet6_netconf_fill_devconf(skb, NETCONFA_IFINDEX_DEFAULT,

@@ -663,9 +712,17 @@ cont:
  					       NETLINK_CB(cb->skb).portid,
  					       cb->nlh->nlmsg_seq,
  					       RTM_NEWNETCONF, NLM_F_MULTI,
-					       -1) <= 0)
+					       AF_INET6, -1) <= 0)
+			goto done;
+#ifdef CONFIG_IPV6_MROUTE

net/ipv6/addrconf.c +0 -0

  	}
  done: