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Commit 4b340ae2 authored by Brian Haley's avatar Brian Haley Committed by David S. Miller
Browse files

IPv6: Complete IPV6_DONTFRAG support 



Finally add support to detect a local IPV6_DONTFRAG event
and return the relevant data to the user if they've enabled
IPV6_RECVPATHMTU on the socket.  The next recvmsg() will
return no data, but have an IPV6_PATHMTU as ancillary data.

Signed-off-by: default avatarBrian Haley <brian.haley@hp.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 13b52cd4

include/linux/ipv6.h

+2 −0
Original line number Diff line number Diff line
@@ -257,6 +257,7 @@ struct inet6_skb_parm { 
};



#define IP6CB(skb)	((struct inet6_skb_parm*)((skb)->cb))

#define IP6CBMTU(skb)	((struct ip6_mtuinfo *)((skb)->cb))



static inline int inet6_iif(const struct sk_buff *skb)

{
@@ -366,6 +367,7 @@ struct ipv6_pinfo { 


	struct ipv6_txoptions	*opt;

	struct sk_buff		*pktoptions;

	struct sk_buff		*rxpmtu;

	struct {

		struct ipv6_txoptions *opt;

		u8 hop_limit;

include/net/ipv6.h

+2 −0
Original line number Diff line number Diff line
@@ -578,9 +578,11 @@ extern int ip6_datagram_connect(struct sock *sk, 
						     struct sockaddr *addr, int addr_len);



extern int 			ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len);

extern int 			ipv6_recv_rxpmtu(struct sock *sk, struct msghdr *msg, int len);

extern void			ipv6_icmp_error(struct sock *sk, struct sk_buff *skb, int err, __be16 port,

						u32 info, u8 *payload);

extern void			ipv6_local_error(struct sock *sk, int err, struct flowi *fl, u32 info);

extern void			ipv6_local_rxpmtu(struct sock *sk, struct flowi *fl, u32 mtu);



extern int inet6_release(struct socket *sock);

extern int inet6_bind(struct socket *sock, struct sockaddr *uaddr,

net/ipv6/af_inet6.c

+3 −0
Original line number Diff line number Diff line
@@ -417,6 +417,9 @@ void inet6_destroy_sock(struct sock *sk) 
	if ((skb = xchg(&np->pktoptions, NULL)) != NULL)

		kfree_skb(skb);



	if ((skb = xchg(&np->rxpmtu, NULL)) != NULL)

		kfree_skb(skb);



	/* Free flowlabels */

	fl6_free_socklist(sk);

net/ipv6/datagram.c

+87 −0
Original line number Diff line number Diff line
@@ -278,6 +278,45 @@ void ipv6_local_error(struct sock *sk, int err, struct flowi *fl, u32 info) 
		kfree_skb(skb);

}



void ipv6_local_rxpmtu(struct sock *sk, struct flowi *fl, u32 mtu)

{

	struct ipv6_pinfo *np = inet6_sk(sk);

	struct ipv6hdr *iph;

	struct sk_buff *skb;

	struct ip6_mtuinfo *mtu_info;



	if (!np->rxopt.bits.rxpmtu)

		return;



	skb = alloc_skb(sizeof(struct ipv6hdr), GFP_ATOMIC);

	if (!skb)

		return;



	skb_put(skb, sizeof(struct ipv6hdr));

	skb_reset_network_header(skb);

	iph = ipv6_hdr(skb);

	ipv6_addr_copy(&iph->daddr, &fl->fl6_dst);



	mtu_info = IP6CBMTU(skb);

	if (!mtu_info) {

		kfree_skb(skb);

		return;

	}



	mtu_info->ip6m_mtu = mtu;

	mtu_info->ip6m_addr.sin6_family = AF_INET6;

	mtu_info->ip6m_addr.sin6_port = 0;

	mtu_info->ip6m_addr.sin6_flowinfo = 0;

	mtu_info->ip6m_addr.sin6_scope_id = fl->oif;

	ipv6_addr_copy(&mtu_info->ip6m_addr.sin6_addr, &ipv6_hdr(skb)->daddr);



	__skb_pull(skb, skb_tail_pointer(skb) - skb->data);

	skb_reset_transport_header(skb);



	skb = xchg(&np->rxpmtu, skb);

	kfree_skb(skb);

}



/*

 *	Handle MSG_ERRQUEUE

 */
@@ -381,6 +420,54 @@ int ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len) 
	return err;

}



/*

 *	Handle IPV6_RECVPATHMTU

 */

int ipv6_recv_rxpmtu(struct sock *sk, struct msghdr *msg, int len)

{

	struct ipv6_pinfo *np = inet6_sk(sk);

	struct sk_buff *skb;

	struct sockaddr_in6 *sin;

	struct ip6_mtuinfo mtu_info;

	int err;

	int copied;



	err = -EAGAIN;

	skb = xchg(&np->rxpmtu, NULL);

	if (skb == NULL)

		goto out;



	copied = skb->len;

	if (copied > len) {

		msg->msg_flags |= MSG_TRUNC;

		copied = len;

	}

	err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);

	if (err)

		goto out_free_skb;



	sock_recv_timestamp(msg, sk, skb);



	memcpy(&mtu_info, IP6CBMTU(skb), sizeof(mtu_info));



	sin = (struct sockaddr_in6 *)msg->msg_name;

	if (sin) {

		sin->sin6_family = AF_INET6;

		sin->sin6_flowinfo = 0;

		sin->sin6_port = 0;

		sin->sin6_scope_id = mtu_info.ip6m_addr.sin6_scope_id;

		ipv6_addr_copy(&sin->sin6_addr, &mtu_info.ip6m_addr.sin6_addr);

	}



	put_cmsg(msg, SOL_IPV6, IPV6_PATHMTU, sizeof(mtu_info), &mtu_info);



	err = copied;



out_free_skb:

	kfree_skb(skb);

out:

	return err;

}





int datagram_recv_ctl(struct sock *sk, struct msghdr *msg, struct sk_buff *skb)

net/ipv6/ip6_output.c

+16 −8
Original line number Diff line number Diff line
@@ -1219,16 +1219,24 @@ int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to, 
	 */



	inet->cork.length += length;

	if (((length > mtu) && (sk->sk_protocol == IPPROTO_UDP)) &&

	if (length > mtu) {

		int proto = sk->sk_protocol;

		if (dontfrag && (proto == IPPROTO_UDP || proto == IPPROTO_RAW)){

			ipv6_local_rxpmtu(sk, fl, mtu-exthdrlen);

			return -EMSGSIZE;

		}



		if (proto == IPPROTO_UDP &&

		    (rt->u.dst.dev->features & NETIF_F_UFO)) {



		err = ip6_ufo_append_data(sk, getfrag, from, length, hh_len,

					  fragheaderlen, transhdrlen, mtu,

					  flags);

			err = ip6_ufo_append_data(sk, getfrag, from, length,

						  hh_len, fragheaderlen,

						  transhdrlen, mtu, flags);

			if (err)

				goto error;

			return 0;

		}

	}



	if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL)

		goto alloc_new_skb;