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: Brian Haley <brian.haley@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
index 1976942..2ab5509 100644 (file)
--- a/include/linux/ipv6.h
+++ b/include/linux/ipv6.h
@@ -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;

diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index 7ab6323..eba5cc0 100644 (file)
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -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, 

diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index 3192aa0..d2df314 100644 (file)
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -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);
 

diff --git a/net/ipv6/datagram.c b/net/ipv6/datagram.c
index f5076d3..5959230 100644 (file)
--- a/net/ipv6/datagram.c
+++ b/net/ipv6/datagram.c
@@ -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 @@ out:
        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)

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 54d43dd..61e2bef 100644 (file)
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -1219,15 +1219,23 @@ 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)) &&
-           (rt->u.dst.dev->features & NETIF_F_UFO)) {
+       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;
+               }
 
-               err = ip6_ufo_append_data(sk, getfrag, from, length, hh_len,
-                                         fragheaderlen, transhdrlen, mtu,
-                                         flags);
-               if (err)
-                       goto error;
-               return 0;
+               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);
+                       if (err)
+                               goto error;
+                       return 0;
+               }
        }
 
        if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL)

diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c
index 44a84ea..8562738 100644 (file)
--- a/net/ipv6/raw.c
+++ b/net/ipv6/raw.c
@@ -461,6 +461,9 @@ static int rawv6_recvmsg(struct kiocb *iocb, struct sock *sk,
        if (flags & MSG_ERRQUEUE)
                return ipv6_recv_error(sk, msg, len);
 
+       if (np->rxpmtu && np->rxopt.bits.rxpmtu)
+               return ipv6_recv_rxpmtu(sk, msg, len);
+
        skb = skb_recv_datagram(sk, flags, noblock, &err);
        if (!skb)
                goto out;

diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 39e3665..2850e35 100644 (file)
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -335,6 +335,9 @@ int udpv6_recvmsg(struct kiocb *iocb, struct sock *sk,
        if (flags & MSG_ERRQUEUE)
                return ipv6_recv_error(sk, msg, len);
 
+       if (np->rxpmtu && np->rxopt.bits.rxpmtu)
+               return ipv6_recv_rxpmtu(sk, msg, len);
+
 try_again:
        skb = __skb_recv_datagram(sk, flags | (noblock ? MSG_DONTWAIT : 0),
                                  &peeked, &err);