IPv6: Add dontfrag argument to relevant functions

Add dontfrag argument to relevant functions for
IPV6_DONTFRAG support, as well as allowing the value
to be passed-in via ancillary cmsg data.
Signed-off-by: Brian Haley <brian.haley@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/ipv6.h

@@ -503,7 +503,8 @@ extern int			ip6_append_data(struct sock *sk,
 						struct ipv6_txoptions *opt,
 						struct flowi *fl,
 						struct rt6_info *rt,
-						unsigned int flags);
+						unsigned int flags,
+						int dontfrag);
 
 extern int			ip6_push_pending_frames(struct sock *sk);
 

include/net/transp_v6.h

@@ -44,7 +44,8 @@ extern int			datagram_send_ctl(struct net *net,
 						  struct msghdr *msg,
 						  struct flowi *fl,
 						  struct ipv6_txoptions *opt,
-						  int *hlimit, int *tclass);
+						  int *hlimit, int *tclass,
+						  int *dontfrag);
 
 #define		LOOPBACK4_IPV6		cpu_to_be32(0x7f000006)
 

net/ipv6/datagram.c

@@ -497,7 +497,7 @@ int datagram_recv_ctl(struct sock *sk, struct msghdr *msg, struct sk_buff *skb)
 int datagram_send_ctl(struct net *net,
 		      struct msghdr *msg, struct flowi *fl,
 		      struct ipv6_txoptions *opt,
-		      int *hlimit, int *tclass)
+		      int *hlimit, int *tclass, int *dontfrag)
 {
 	struct in6_pktinfo *src_info;
 	struct cmsghdr *cmsg;
@@ -735,6 +735,25 @@ int datagram_send_ctl(struct net *net,
 			err = 0;
 			*tclass = tc;
 
+			break;
+		    }
+
+		case IPV6_DONTFRAG:
+		    {
+			int df;
+
+			err = -EINVAL;
+			if (cmsg->cmsg_len != CMSG_LEN(sizeof(int))) {
+				goto exit_f;
+			}
+
+			df = *(int *)CMSG_DATA(cmsg);
+			if (df < 0 || df > 1)
+				goto exit_f;
+
+			err = 0;
+			*dontfrag = df;
+
 			break;
 		    }
 		default:

net/ipv6/icmp.c

@@ -481,7 +481,7 @@ void icmpv6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info)
 			      len + sizeof(struct icmp6hdr),
 			      sizeof(struct icmp6hdr), hlimit,
 			      np->tclass, NULL, &fl, (struct rt6_info*)dst,
-			      MSG_DONTWAIT);
+			      MSG_DONTWAIT, np->dontfrag);
 	if (err) {
 		ICMP6_INC_STATS_BH(net, idev, ICMP6_MIB_OUTMSGS);
 		ip6_flush_pending_frames(sk);
@@ -561,7 +561,8 @@ static void icmpv6_echo_reply(struct sk_buff *skb)
 
 	err = ip6_append_data(sk, icmpv6_getfrag, &msg, skb->len + sizeof(struct icmp6hdr),
 				sizeof(struct icmp6hdr), hlimit, np->tclass, NULL, &fl,
-				(struct rt6_info*)dst, MSG_DONTWAIT);
+				(struct rt6_info*)dst, MSG_DONTWAIT,
+				np->dontfrag);
 
 	if (err) {
 		ICMP6_INC_STATS_BH(net, idev, ICMP6_MIB_OUTMSGS);

net/ipv6/ip6_flowlabel.c

@@ -360,7 +360,8 @@ fl_create(struct net *net, struct in6_flowlabel_req *freq, char __user *optval,
 		msg.msg_control = (void*)(fl->opt+1);
 		flowi.oif = 0;
 
-		err = datagram_send_ctl(net, &msg, &flowi, fl->opt, &junk, &junk);
+		err = datagram_send_ctl(net, &msg, &flowi, fl->opt, &junk,
+					&junk, &junk);
 		if (err)
 			goto done;
 		err = -EINVAL;

net/ipv6/ip6_output.c

@@ -1105,7 +1105,7 @@ int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to,
 	int offset, int len, int odd, struct sk_buff *skb),
 	void *from, int length, int transhdrlen,
 	int hlimit, int tclass, struct ipv6_txoptions *opt, struct flowi *fl,
-	struct rt6_info *rt, unsigned int flags)
+	struct rt6_info *rt, unsigned int flags, int dontfrag)
 {
 	struct inet_sock *inet = inet_sk(sk);
 	struct ipv6_pinfo *np = inet6_sk(sk);

net/ipv6/ipv6_sockglue.c

@@ -458,7 +458,8 @@ static int do_ipv6_setsockopt(struct sock *sk, int level, int optname,
 		msg.msg_controllen = optlen;
 		msg.msg_control = (void*)(opt+1);
 
-		retv = datagram_send_ctl(net, &msg, &fl, opt, &junk, &junk);
+		retv = datagram_send_ctl(net, &msg, &fl, opt, &junk, &junk,
+					 &junk);
 		if (retv)
 			goto done;
 update:

net/ipv6/raw.c

@@ -733,6 +733,7 @@ static int rawv6_sendmsg(struct kiocb *iocb, struct sock *sk,
 	int addr_len = msg->msg_namelen;
 	int hlimit = -1;
 	int tclass = -1;
+	int dontfrag = -1;
 	u16 proto;
 	int err;
 
@@ -811,7 +812,8 @@ static int rawv6_sendmsg(struct kiocb *iocb, struct sock *sk,
 		memset(opt, 0, sizeof(struct ipv6_txoptions));
 		opt->tot_len = sizeof(struct ipv6_txoptions);
 
-		err = datagram_send_ctl(sock_net(sk), msg, &fl, opt, &hlimit, &tclass);
+		err = datagram_send_ctl(sock_net(sk), msg, &fl, opt, &hlimit,
+					&tclass, &dontfrag);
 		if (err < 0) {
 			fl6_sock_release(flowlabel);
 			return err;
@@ -880,6 +882,9 @@ static int rawv6_sendmsg(struct kiocb *iocb, struct sock *sk,
 	if (tclass < 0)
 		tclass = np->tclass;
 
+	if (dontfrag < 0)
+		dontfrag = np->dontfrag;
+
 	if (msg->msg_flags&MSG_CONFIRM)
 		goto do_confirm;
 
@@ -890,7 +895,7 @@ static int rawv6_sendmsg(struct kiocb *iocb, struct sock *sk,
 		lock_sock(sk);
 		err = ip6_append_data(sk, ip_generic_getfrag, msg->msg_iov,
 			len, 0, hlimit, tclass, opt, &fl, (struct rt6_info*)dst,
-			msg->msg_flags);
+			msg->msg_flags, dontfrag);
 
 		if (err)
 			ip6_flush_pending_frames(sk);

net/ipv6/udp.c

@@ -919,6 +919,7 @@ int udpv6_sendmsg(struct kiocb *iocb, struct sock *sk,
 	int ulen = len;
 	int hlimit = -1;
 	int tclass = -1;
+	int dontfrag = -1;
 	int corkreq = up->corkflag || msg->msg_flags&MSG_MORE;
 	int err;
 	int connected = 0;
@@ -1049,7 +1050,8 @@ int udpv6_sendmsg(struct kiocb *iocb, struct sock *sk,
 		memset(opt, 0, sizeof(struct ipv6_txoptions));
 		opt->tot_len = sizeof(*opt);
 
-		err = datagram_send_ctl(sock_net(sk), msg, &fl, opt, &hlimit, &tclass);
+		err = datagram_send_ctl(sock_net(sk), msg, &fl, opt, &hlimit,
+					&tclass, &dontfrag);
 		if (err < 0) {
 			fl6_sock_release(flowlabel);
 			return err;
@@ -1120,6 +1122,9 @@ int udpv6_sendmsg(struct kiocb *iocb, struct sock *sk,
 	if (tclass < 0)
 		tclass = np->tclass;
 
+	if (dontfrag < 0)
+		dontfrag = np->dontfrag;
+
 	if (msg->msg_flags&MSG_CONFIRM)
 		goto do_confirm;
 back_from_confirm:
@@ -1143,7 +1148,7 @@ int udpv6_sendmsg(struct kiocb *iocb, struct sock *sk,
 	err = ip6_append_data(sk, getfrag, msg->msg_iov, ulen,
 		sizeof(struct udphdr), hlimit, tclass, opt, &fl,
 		(struct rt6_info*)dst,
-		corkreq ? msg->msg_flags|MSG_MORE : msg->msg_flags);
+		corkreq ? msg->msg_flags|MSG_MORE : msg->msg_flags, dontfrag);
 	if (err)
 		udp_v6_flush_pending_frames(sk);
 	else if (!corkreq)