diff mbox

[net-next,v3,1/3] net: ipv6: Unduplicate {raw,udp}v6_sendmsg code

Message ID 1398179656-9313-1-git-send-email-lorenzo@google.com
State Superseded, archived
Delegated to: David Miller
Headers show

Commit Message

Lorenzo Colitti April 22, 2014, 3:14 p.m. UTC 
rawv6_sendmsg and udpv6_sendmsg have ~100 lines of almost
identical code. Move this into a new ipv6_datagram_send_common
helper function.

Tested: black-box tested using user-mode Linux.

- Basic UDP sends using sendto work.
- Mark routing and oif routing using SO_BINDTODEVICE work.

Signed-off-by: Lorenzo Colitti <lorenzo@google.com>
---
 include/net/ipv6.h  |   7 +++
 net/ipv6/datagram.c | 133 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 net/ipv6/raw.c      | 107 ++++--------------------------------------
 net/ipv6/udp.c      | 117 ++++-----------------------------------------
 4 files changed, 156 insertions(+), 208 deletions(-)

Comments

Hannes Frederic Sowa April 22, 2014, 3:48 p.m. UTC | #1 
Hi!

On Wed, Apr 23, 2014 at 12:14:14AM +0900, Lorenzo Colitti wrote:
> rawv6_sendmsg and udpv6_sendmsg have ~100 lines of almost
> identical code. Move this into a new ipv6_datagram_send_common
> helper function.
> 
> Tested: black-box tested using user-mode Linux.
> 
> - Basic UDP sends using sendto work.
> - Mark routing and oif routing using SO_BINDTODEVICE work.
> 
> Signed-off-by: Lorenzo Colitti <lorenzo@google.com>
> ---
>  include/net/ipv6.h  |   7 +++
>  net/ipv6/datagram.c | 133 ++++++++++++++++++++++++++++++++++++++++++++++++++++
>  net/ipv6/raw.c      | 107 ++++--------------------------------------
>  net/ipv6/udp.c      | 117 ++++-----------------------------------------
>  4 files changed, 156 insertions(+), 208 deletions(-)
> 
> diff --git a/include/net/ipv6.h b/include/net/ipv6.h
> index d640925..f1a247a 100644
> --- a/include/net/ipv6.h
> +++ b/include/net/ipv6.h
> @@ -785,6 +785,13 @@ int compat_ipv6_getsockopt(struct sock *sk, int level, int optname,
>  int ip6_datagram_connect(struct sock *sk, struct sockaddr *addr, int addr_len);
>  int ip6_datagram_connect_v6_only(struct sock *sk, struct sockaddr *addr,
>  				 int addr_len);
> +int ip6_datagram_send_common(struct sock *sk, struct msghdr *msg,
> +			     struct sockaddr_in6 *sin6, int addr_len,
> +			     struct flowi6 *fl6, struct dst_entry **dstp,
> +			     struct ipv6_txoptions **optp,
> +			     struct ipv6_txoptions *opt_space,
> +			     int *hlimit, int *tclass, int *dontfrag,
> +			     int *connected);
>  
>  int ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len,
>  		    int *addr_len);
> diff --git a/net/ipv6/datagram.c b/net/ipv6/datagram.c
> index c3bf2d2..e6df861 100644
> --- a/net/ipv6/datagram.c
> +++ b/net/ipv6/datagram.c
> @@ -915,6 +915,139 @@ exit_f:
>  }
>  EXPORT_SYMBOL_GPL(ip6_datagram_send_ctl);
>  
> +int ip6_datagram_send_common(struct sock *sk, struct msghdr *msg,
> +			     struct sockaddr_in6 *sin6, int addr_len,
> +			     struct flowi6 *fl6, struct dst_entry **dstp,
> +			     struct ipv6_txoptions **optp,
> +			     struct ipv6_txoptions *opt_space,
> +			     int *hlimit, int *tclass, int *dontfrag,
> +			     int *connected)
> +{
> +	struct ipv6_txoptions *opt = NULL;
> +	struct ip6_flowlabel *flowlabel = NULL;
> +	struct in6_addr *final_p, final;
> +	struct ipv6_pinfo *np = inet6_sk(sk);
> +	struct in6_addr *daddr;
> +	struct dst_entry *dst;
> +	int err;
> +
> +	*optp = NULL;
> +	*dstp = NULL;
> +	*hlimit = *tclass = *dontfrag = -1;

Do we need those? If we return != 0 from ip6_datagram_send_common we
know the in/out arguments may or maybe got an update an as such cannot
use them.

Caller can initialize dstp = NULL so we can pass dstp to dst_release in the
error path in the caller function (dst_release checks for argument != NULL).

Does that make sense? It looks to me like it could hide errors, but just IMHO.

> +
> +	if (sin6) {
> +		daddr = &sin6->sin6_addr;
> +
> +		if (np->sndflow) {
> +			fl6->flowlabel = sin6->sin6_flowinfo&IPV6_FLOWINFO_MASK;
> +			if (fl6->flowlabel&IPV6_FLOWLABEL_MASK) {
> +				flowlabel = fl6_sock_lookup(sk, fl6->flowlabel);
> +				if (flowlabel == NULL)
> +					return -EINVAL;
> +			}
> +		}
> +
> +		/* Otherwise it will be difficult to maintain
> +		 * sk->sk_dst_cache.
> +		 */
> +		if (sk->sk_state == TCP_ESTABLISHED &&
> +		    ipv6_addr_equal(daddr, &sk->sk_v6_daddr))
> +			daddr = &sk->sk_v6_daddr;
> +
> +		if (addr_len >= sizeof(struct sockaddr_in6) &&
> +		    sin6->sin6_scope_id &&
> +		    __ipv6_addr_needs_scope_id(__ipv6_addr_type(daddr)))
> +			fl6->flowi6_oif = sin6->sin6_scope_id;
> +	} else {
> +		if (sk->sk_state != TCP_ESTABLISHED)
> +			return -EDESTADDRREQ;
> +
> +		daddr = &sk->sk_v6_daddr;
> +		fl6->flowlabel = np->flow_label;
> +		*connected = 1;
> +	}
> +
> +	if (!fl6->flowi6_oif)
> +		fl6->flowi6_oif = sk->sk_bound_dev_if;
> +
> +	if (!fl6->flowi6_oif)
> +		fl6->flowi6_oif = np->sticky_pktinfo.ipi6_ifindex;
> +
> +	fl6->flowi6_mark = sk->sk_mark;
> +
> +	if (msg->msg_controllen) {
> +		opt = opt_space;
> +		memset(opt, 0, sizeof(*opt));
> +		opt->tot_len = sizeof(*opt);
> +
> +		err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, fl6, opt,
> +					    hlimit, tclass, dontfrag);
> +		if (err < 0) {
> +			fl6_sock_release(flowlabel);
> +			return err;
> +		}
> +		if ((fl6->flowlabel&IPV6_FLOWLABEL_MASK) && !flowlabel) {
> +			flowlabel = fl6_sock_lookup(sk, fl6->flowlabel);
> +			if (flowlabel == NULL)
> +				return -EINVAL;
> +		}
> +		if (!(opt->opt_nflen|opt->opt_flen))
> +			opt = NULL;
> +		*connected = 0;
> +	}
> +	if (opt == NULL)
> +		opt = np->opt;
> +	if (flowlabel)
> +		opt = fl6_merge_options(opt_space, flowlabel, opt);
> +	opt = ipv6_fixup_options(opt_space, opt);
> +
> +	if (!ipv6_addr_any(daddr))
> +		fl6->daddr = *daddr;
> +	else
> +		fl6->daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */

Maybe a newline?

> +	if (ipv6_addr_any(&fl6->saddr) && !ipv6_addr_any(&np->saddr))
> +		fl6->saddr = np->saddr;
> +
> +	final_p = fl6_update_dst(fl6, opt, &final);
> +	if (final_p)
> +		*connected = 0;
> +
> +	if (!fl6->flowi6_oif && ipv6_addr_is_multicast(&fl6->daddr)) {
> +		fl6->flowi6_oif = np->mcast_oif;
> +		*connected = 0;
> +	} else if (!fl6->flowi6_oif)
> +		fl6->flowi6_oif = np->ucast_oif;
> +
> +	security_sk_classify_flow(sk, flowi6_to_flowi(fl6));
> +
> +	dst = ip6_sk_dst_lookup_flow(sk, fl6, final_p);
> +	if (IS_ERR(dst)) {
> +		fl6_sock_release(flowlabel);
> +		return PTR_ERR(dst);
> +	}
> +
> +	if (*hlimit < 0) {
> +		if (ipv6_addr_is_multicast(&fl6->daddr))
> +			*hlimit = np->mcast_hops;
> +		else
> +			*hlimit = np->hop_limit;
> +		if (*hlimit < 0)
> +			*hlimit = ip6_dst_hoplimit(dst);
> +	}
> +
> +	if (*tclass < 0)
> +		*tclass = np->tclass;
> +
> +	if (*dontfrag < 0)
> +		*dontfrag = np->dontfrag;
> +
> +	*dstp = dst;
> +	*optp = opt;

We would also need a fl6_sock_release here because we finished processing
it.

You could also release the flowlabel after fl6_merge_options and could remove
the fl6_sock_release after ip6_sk_dst_lookup_flow in the error handling.

> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(ip6_datagram_send_common);

The rest looks good to me and is a nice work!

Thanks,

  Hannes

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Eric Dumazet April 22, 2014, 3:59 p.m. UTC | #2 
On Wed, 2014-04-23 at 00:14 +0900, Lorenzo Colitti wrote:

> +	dst = ip6_sk_dst_lookup_flow(sk, fl6, final_p);
> +	if (IS_ERR(dst)) {
> +		fl6_sock_release(flowlabel);
> +		return PTR_ERR(dst);
> +	}
> +
> +	if (*hlimit < 0) {
> +		if (ipv6_addr_is_multicast(&fl6->daddr))
> +			*hlimit = np->mcast_hops;
> +		else
> +			*hlimit = np->hop_limit;
> +		if (*hlimit < 0)
> +			*hlimit = ip6_dst_hoplimit(dst);
> +	}
> +
> +	if (*tclass < 0)
> +		*tclass = np->tclass;
> +
> +	if (*dontfrag < 0)
> +		*dontfrag = np->dontfrag;
> +
> +	*dstp = dst;
> +	*optp = opt;
> +
> +	return 0;
> +}


Don't you leak a reference on struct ip6_flowlabel *flowlabel ?


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Lorenzo Colitti April 23, 2014, 6:37 a.m. UTC | #3 
On Wed, Apr 23, 2014 at 12:48 AM, Hannes Frederic Sowa
<hannes@stressinduktion.org> wrote:
>> +     *optp = NULL;
>> +     *dstp = NULL;
>> +     *hlimit = *tclass = *dontfrag = -1;
>
> Do we need those? If we return != 0 from ip6_datagram_send_common we
> know the in/out arguments may or maybe got an update an as such cannot
> use them.
>
> Caller can initialize dstp = NULL so we can pass dstp to dst_release in the
> error path in the caller function (dst_release checks for argument != NULL).

Initalizing optp was not useful. As you say, the callers won't use it
if we return an error. I've removed it.

I've also removed the initialization of dstp. After thinking about it,
I agree it's bad for the callers to rely on this function to set dstp
to NULL on failure. It's more reasonable for the callers to assume
that the dst pointer they pass in won't be touched on failure.

As for hlimit, tclass and dontfrag, they (and connected), I think it's
useful to initialize them here because it simplifies the code. Since
we set them to -1 early on, we can later do things like "if (*hlimit <
0) { set the default hop limit }" and have things work regardless of
whether a hop limit was passed in via cmsg. I don't think it's
confusing: variables are all calculated and returned by this function,
and the callers should not be setting them since they have no
information on what to set them to. Also, they don't need to be freed.
I've moved them closer to where they are actually set.

>> +     if (!ipv6_addr_any(daddr))
>> +             fl6->daddr = *daddr;
>> +     else
>> +             fl6->daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
>
> Maybe a newline?

Added.

> We would also need a fl6_sock_release here because we finished processing
> it.
>
> You could also release the flowlabel after fl6_merge_options and could remove
> the fl6_sock_release after ip6_sk_dst_lookup_flow in the error handling.

Yes, that's better. Done.
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Lorenzo Colitti April 23, 2014, 6:38 a.m. UTC | #4 
On Wed, Apr 23, 2014 at 12:59 AM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
> Don't you leak a reference on struct ip6_flowlabel *flowlabel ?

Yes. Should be fixed in patch series 4.
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diff mbox

Patch

diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index d640925..f1a247a 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -785,6 +785,13 @@  int compat_ipv6_getsockopt(struct sock *sk, int level, int optname,
 int ip6_datagram_connect(struct sock *sk, struct sockaddr *addr, int addr_len);
 int ip6_datagram_connect_v6_only(struct sock *sk, struct sockaddr *addr,
 				 int addr_len);
+int ip6_datagram_send_common(struct sock *sk, struct msghdr *msg,
+			     struct sockaddr_in6 *sin6, int addr_len,
+			     struct flowi6 *fl6, struct dst_entry **dstp,
+			     struct ipv6_txoptions **optp,
+			     struct ipv6_txoptions *opt_space,
+			     int *hlimit, int *tclass, int *dontfrag,
+			     int *connected);
 
 int ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len,
 		    int *addr_len);
diff --git a/net/ipv6/datagram.c b/net/ipv6/datagram.c
index c3bf2d2..e6df861 100644
--- a/net/ipv6/datagram.c
+++ b/net/ipv6/datagram.c
@@ -915,6 +915,139 @@  exit_f:
 }
 EXPORT_SYMBOL_GPL(ip6_datagram_send_ctl);
 
+int ip6_datagram_send_common(struct sock *sk, struct msghdr *msg,
+			     struct sockaddr_in6 *sin6, int addr_len,
+			     struct flowi6 *fl6, struct dst_entry **dstp,
+			     struct ipv6_txoptions **optp,
+			     struct ipv6_txoptions *opt_space,
+			     int *hlimit, int *tclass, int *dontfrag,
+			     int *connected)
+{
+	struct ipv6_txoptions *opt = NULL;
+	struct ip6_flowlabel *flowlabel = NULL;
+	struct in6_addr *final_p, final;
+	struct ipv6_pinfo *np = inet6_sk(sk);
+	struct in6_addr *daddr;
+	struct dst_entry *dst;
+	int err;
+
+	*optp = NULL;
+	*dstp = NULL;
+	*hlimit = *tclass = *dontfrag = -1;
+
+	if (sin6) {
+		daddr = &sin6->sin6_addr;
+
+		if (np->sndflow) {
+			fl6->flowlabel = sin6->sin6_flowinfo&IPV6_FLOWINFO_MASK;
+			if (fl6->flowlabel&IPV6_FLOWLABEL_MASK) {
+				flowlabel = fl6_sock_lookup(sk, fl6->flowlabel);
+				if (flowlabel == NULL)
+					return -EINVAL;
+			}
+		}
+
+		/* Otherwise it will be difficult to maintain
+		 * sk->sk_dst_cache.
+		 */
+		if (sk->sk_state == TCP_ESTABLISHED &&
+		    ipv6_addr_equal(daddr, &sk->sk_v6_daddr))
+			daddr = &sk->sk_v6_daddr;
+
+		if (addr_len >= sizeof(struct sockaddr_in6) &&
+		    sin6->sin6_scope_id &&
+		    __ipv6_addr_needs_scope_id(__ipv6_addr_type(daddr)))
+			fl6->flowi6_oif = sin6->sin6_scope_id;
+	} else {
+		if (sk->sk_state != TCP_ESTABLISHED)
+			return -EDESTADDRREQ;
+
+		daddr = &sk->sk_v6_daddr;
+		fl6->flowlabel = np->flow_label;
+		*connected = 1;
+	}
+
+	if (!fl6->flowi6_oif)
+		fl6->flowi6_oif = sk->sk_bound_dev_if;
+
+	if (!fl6->flowi6_oif)
+		fl6->flowi6_oif = np->sticky_pktinfo.ipi6_ifindex;
+
+	fl6->flowi6_mark = sk->sk_mark;
+
+	if (msg->msg_controllen) {
+		opt = opt_space;
+		memset(opt, 0, sizeof(*opt));
+		opt->tot_len = sizeof(*opt);
+
+		err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, fl6, opt,
+					    hlimit, tclass, dontfrag);
+		if (err < 0) {
+			fl6_sock_release(flowlabel);
+			return err;
+		}
+		if ((fl6->flowlabel&IPV6_FLOWLABEL_MASK) && !flowlabel) {
+			flowlabel = fl6_sock_lookup(sk, fl6->flowlabel);
+			if (flowlabel == NULL)
+				return -EINVAL;
+		}
+		if (!(opt->opt_nflen|opt->opt_flen))
+			opt = NULL;
+		*connected = 0;
+	}
+	if (opt == NULL)
+		opt = np->opt;
+	if (flowlabel)
+		opt = fl6_merge_options(opt_space, flowlabel, opt);
+	opt = ipv6_fixup_options(opt_space, opt);
+
+	if (!ipv6_addr_any(daddr))
+		fl6->daddr = *daddr;
+	else
+		fl6->daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
+	if (ipv6_addr_any(&fl6->saddr) && !ipv6_addr_any(&np->saddr))
+		fl6->saddr = np->saddr;
+
+	final_p = fl6_update_dst(fl6, opt, &final);
+	if (final_p)
+		*connected = 0;
+
+	if (!fl6->flowi6_oif && ipv6_addr_is_multicast(&fl6->daddr)) {
+		fl6->flowi6_oif = np->mcast_oif;
+		*connected = 0;
+	} else if (!fl6->flowi6_oif)
+		fl6->flowi6_oif = np->ucast_oif;
+
+	security_sk_classify_flow(sk, flowi6_to_flowi(fl6));
+
+	dst = ip6_sk_dst_lookup_flow(sk, fl6, final_p);
+	if (IS_ERR(dst)) {
+		fl6_sock_release(flowlabel);
+		return PTR_ERR(dst);
+	}
+
+	if (*hlimit < 0) {
+		if (ipv6_addr_is_multicast(&fl6->daddr))
+			*hlimit = np->mcast_hops;
+		else
+			*hlimit = np->hop_limit;
+		if (*hlimit < 0)
+			*hlimit = ip6_dst_hoplimit(dst);
+	}
+
+	if (*tclass < 0)
+		*tclass = np->tclass;
+
+	if (*dontfrag < 0)
+		*dontfrag = np->dontfrag;
+
+	*dstp = dst;
+	*optp = opt;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(ip6_datagram_send_common);
+
 void ip6_dgram_sock_seq_show(struct seq_file *seq, struct sock *sp,
 			     __u16 srcp, __u16 destp, int bucket)
 {
diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c
index 1f29996..212fc95 100644
--- a/net/ipv6/raw.c
+++ b/net/ipv6/raw.c
@@ -739,20 +739,16 @@  static int rawv6_sendmsg(struct kiocb *iocb, struct sock *sk,
 {
 	struct ipv6_txoptions opt_space;
 	DECLARE_SOCKADDR(struct sockaddr_in6 *, sin6, msg->msg_name);
-	struct in6_addr *daddr, *final_p, final;
 	struct inet_sock *inet = inet_sk(sk);
-	struct ipv6_pinfo *np = inet6_sk(sk);
 	struct raw6_sock *rp = raw6_sk(sk);
-	struct ipv6_txoptions *opt = NULL;
-	struct ip6_flowlabel *flowlabel = NULL;
-	struct dst_entry *dst = NULL;
+	struct ipv6_txoptions *opt;
+	struct dst_entry *dst;
 	struct flowi6 fl6;
 	int addr_len = msg->msg_namelen;
-	int hlimit = -1;
-	int tclass = -1;
-	int dontfrag = -1;
+	int hlimit, tclass, dontfrag;
 	u16 proto;
 	int err;
+	int connected;
 
 	/* Rough check on arithmetic overflow,
 	   better check is made in ip6_append_data().
@@ -769,8 +765,6 @@  static int rawv6_sendmsg(struct kiocb *iocb, struct sock *sk,
 	 */
 	memset(&fl6, 0, sizeof(fl6));
 
-	fl6.flowi6_mark = sk->sk_mark;
-
 	if (sin6) {
 		if (addr_len < SIN6_LEN_RFC2133)
 			return -EINVAL;
@@ -788,105 +782,21 @@  static int rawv6_sendmsg(struct kiocb *iocb, struct sock *sk,
 
 		if (proto > 255)
 			return -EINVAL;
-
-		daddr = &sin6->sin6_addr;
-		if (np->sndflow) {
-			fl6.flowlabel = sin6->sin6_flowinfo&IPV6_FLOWINFO_MASK;
-			if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
-				flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
-				if (flowlabel == NULL)
-					return -EINVAL;
-			}
-		}
-
-		/*
-		 * Otherwise it will be difficult to maintain
-		 * sk->sk_dst_cache.
-		 */
-		if (sk->sk_state == TCP_ESTABLISHED &&
-		    ipv6_addr_equal(daddr, &sk->sk_v6_daddr))
-			daddr = &sk->sk_v6_daddr;
-
-		if (addr_len >= sizeof(struct sockaddr_in6) &&
-		    sin6->sin6_scope_id &&
-		    __ipv6_addr_needs_scope_id(__ipv6_addr_type(daddr)))
-			fl6.flowi6_oif = sin6->sin6_scope_id;
 	} else {
-		if (sk->sk_state != TCP_ESTABLISHED)
-			return -EDESTADDRREQ;
-
 		proto = inet->inet_num;
-		daddr = &sk->sk_v6_daddr;
-		fl6.flowlabel = np->flow_label;
 	}
 
-	if (fl6.flowi6_oif == 0)
-		fl6.flowi6_oif = sk->sk_bound_dev_if;
-
-	if (msg->msg_controllen) {
-		opt = &opt_space;
-		memset(opt, 0, sizeof(struct ipv6_txoptions));
-		opt->tot_len = sizeof(struct ipv6_txoptions);
-
-		err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6, opt,
-					    &hlimit, &tclass, &dontfrag);
-		if (err < 0) {
-			fl6_sock_release(flowlabel);
-			return err;
-		}
-		if ((fl6.flowlabel&IPV6_FLOWLABEL_MASK) && !flowlabel) {
-			flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
-			if (flowlabel == NULL)
-				return -EINVAL;
-		}
-		if (!(opt->opt_nflen|opt->opt_flen))
-			opt = NULL;
-	}
-	if (opt == NULL)
-		opt = np->opt;
-	if (flowlabel)
-		opt = fl6_merge_options(&opt_space, flowlabel, opt);
-	opt = ipv6_fixup_options(&opt_space, opt);
-
 	fl6.flowi6_proto = proto;
 	err = rawv6_probe_proto_opt(&fl6, msg);
 	if (err)
 		goto out;
 
-	if (!ipv6_addr_any(daddr))
-		fl6.daddr = *daddr;
-	else
-		fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
-	if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr))
-		fl6.saddr = np->saddr;
-
-	final_p = fl6_update_dst(&fl6, opt, &final);
-
-	if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
-		fl6.flowi6_oif = np->mcast_oif;
-	else if (!fl6.flowi6_oif)
-		fl6.flowi6_oif = np->ucast_oif;
-	security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
-
-	dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
-	if (IS_ERR(dst)) {
-		err = PTR_ERR(dst);
+	err = ip6_datagram_send_common(sk, msg, sin6, addr_len, &fl6, &dst,
+				       &opt, &opt_space, &hlimit, &tclass,
+				       &dontfrag, &connected);
+	if (err)
 		goto out;
-	}
-	if (hlimit < 0) {
-		if (ipv6_addr_is_multicast(&fl6.daddr))
-			hlimit = np->mcast_hops;
-		else
-			hlimit = np->hop_limit;
-		if (hlimit < 0)
-			hlimit = ip6_dst_hoplimit(dst);
-	}
-
-	if (tclass < 0)
-		tclass = np->tclass;
 
-	if (dontfrag < 0)
-		dontfrag = np->dontfrag;
 
 	if (msg->msg_flags&MSG_CONFIRM)
 		goto do_confirm;
@@ -909,7 +819,6 @@  back_from_confirm:
 done:
 	dst_release(dst);
 out:
-	fl6_sock_release(flowlabel);
 	return err<0?err:len;
 do_confirm:
 	dst_confirm(dst);
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 1e586d9..777b423 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -1044,16 +1044,13 @@  int udpv6_sendmsg(struct kiocb *iocb, struct sock *sk,
 	struct inet_sock *inet = inet_sk(sk);
 	struct ipv6_pinfo *np = inet6_sk(sk);
 	DECLARE_SOCKADDR(struct sockaddr_in6 *, sin6, msg->msg_name);
-	struct in6_addr *daddr, *final_p, final;
-	struct ipv6_txoptions *opt = NULL;
-	struct ip6_flowlabel *flowlabel = NULL;
+	struct in6_addr *daddr;
+	struct ipv6_txoptions *opt;
 	struct flowi6 fl6;
 	struct dst_entry *dst;
 	int addr_len = msg->msg_namelen;
 	int ulen = len;
-	int hlimit = -1;
-	int tclass = -1;
-	int dontfrag = -1;
+	int hlimit, tclass, dontfrag;
 	int corkreq = up->corkflag || msg->msg_flags&MSG_MORE;
 	int err;
 	int connected = 0;
@@ -1131,118 +1128,23 @@  do_udp_sendmsg:
 	ulen += sizeof(struct udphdr);
 
 	memset(&fl6, 0, sizeof(fl6));
+	fl6.flowi6_proto = sk->sk_protocol;
 
 	if (sin6) {
 		if (sin6->sin6_port == 0)
 			return -EINVAL;
 
 		fl6.fl6_dport = sin6->sin6_port;
-		daddr = &sin6->sin6_addr;
-
-		if (np->sndflow) {
-			fl6.flowlabel = sin6->sin6_flowinfo&IPV6_FLOWINFO_MASK;
-			if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
-				flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
-				if (flowlabel == NULL)
-					return -EINVAL;
-			}
-		}
-
-		/*
-		 * Otherwise it will be difficult to maintain
-		 * sk->sk_dst_cache.
-		 */
-		if (sk->sk_state == TCP_ESTABLISHED &&
-		    ipv6_addr_equal(daddr, &sk->sk_v6_daddr))
-			daddr = &sk->sk_v6_daddr;
-
-		if (addr_len >= sizeof(struct sockaddr_in6) &&
-		    sin6->sin6_scope_id &&
-		    __ipv6_addr_needs_scope_id(__ipv6_addr_type(daddr)))
-			fl6.flowi6_oif = sin6->sin6_scope_id;
 	} else {
-		if (sk->sk_state != TCP_ESTABLISHED)
-			return -EDESTADDRREQ;
-
 		fl6.fl6_dport = inet->inet_dport;
-		daddr = &sk->sk_v6_daddr;
-		fl6.flowlabel = np->flow_label;
-		connected = 1;
-	}
-
-	if (!fl6.flowi6_oif)
-		fl6.flowi6_oif = sk->sk_bound_dev_if;
-
-	if (!fl6.flowi6_oif)
-		fl6.flowi6_oif = np->sticky_pktinfo.ipi6_ifindex;
-
-	fl6.flowi6_mark = sk->sk_mark;
-
-	if (msg->msg_controllen) {
-		opt = &opt_space;
-		memset(opt, 0, sizeof(struct ipv6_txoptions));
-		opt->tot_len = sizeof(*opt);
-
-		err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6, opt,
-					    &hlimit, &tclass, &dontfrag);
-		if (err < 0) {
-			fl6_sock_release(flowlabel);
-			return err;
-		}
-		if ((fl6.flowlabel&IPV6_FLOWLABEL_MASK) && !flowlabel) {
-			flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
-			if (flowlabel == NULL)
-				return -EINVAL;
-		}
-		if (!(opt->opt_nflen|opt->opt_flen))
-			opt = NULL;
-		connected = 0;
 	}
-	if (opt == NULL)
-		opt = np->opt;
-	if (flowlabel)
-		opt = fl6_merge_options(&opt_space, flowlabel, opt);
-	opt = ipv6_fixup_options(&opt_space, opt);
-
-	fl6.flowi6_proto = sk->sk_protocol;
-	if (!ipv6_addr_any(daddr))
-		fl6.daddr = *daddr;
-	else
-		fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
-	if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr))
-		fl6.saddr = np->saddr;
 	fl6.fl6_sport = inet->inet_sport;
 
-	final_p = fl6_update_dst(&fl6, opt, &final);
-	if (final_p)
-		connected = 0;
-
-	if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) {
-		fl6.flowi6_oif = np->mcast_oif;
-		connected = 0;
-	} else if (!fl6.flowi6_oif)
-		fl6.flowi6_oif = np->ucast_oif;
-
-	security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
-
-	dst = ip6_sk_dst_lookup_flow(sk, &fl6, final_p);
-	if (IS_ERR(dst)) {
-		err = PTR_ERR(dst);
-		dst = NULL;
+	err = ip6_datagram_send_common(sk, msg, sin6, addr_len, &fl6, &dst,
+				       &opt, &opt_space, &hlimit, &tclass,
+				       &dontfrag, &connected);
+	if (err)
 		goto out;
-	}
-
-	if (hlimit < 0) {
-		if (ipv6_addr_is_multicast(&fl6.daddr))
-			hlimit = np->mcast_hops;
-		else
-			hlimit = np->hop_limit;
-		if (hlimit < 0)
-			hlimit = ip6_dst_hoplimit(dst);
-	}
-
-	if (tclass < 0)
-		tclass = np->tclass;
 
 	if (msg->msg_flags&MSG_CONFIRM)
 		goto do_confirm;
@@ -1262,8 +1164,6 @@  back_from_confirm:
 	up->pending = AF_INET6;
 
 do_append_data:
-	if (dontfrag < 0)
-		dontfrag = np->dontfrag;
 	up->len += ulen;
 	getfrag  =  is_udplite ?  udplite_getfrag : ip_generic_getfrag;
 	err = ip6_append_data(sk, getfrag, msg->msg_iov, ulen,
@@ -1298,7 +1198,6 @@  do_append_data:
 	release_sock(sk);
 out:
 	dst_release(dst);
-	fl6_sock_release(flowlabel);
 	if (!err)
 		return len;
 	/*