[ATALK]: endianness annotations

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 30 insertions, 94 deletions

diff --git a/drivers/net/appletalk/ipddp.c b/drivers/net/appletalk/ipddp.c
index 7f7dd450226a..b98592a8bac8 100644
--- a/drivers/net/appletalk/ipddp.c
+++ b/drivers/net/appletalk/ipddp.c
@@ -145,9 +145,7 @@ static int ipddp_xmit(struct sk_buff *skb, struct net_device *dev)
 
         /* Create the Extended DDP header */
         ddp = (struct ddpehdr *)skb->data;
-        ddp->deh_len = skb->len;
-        ddp->deh_hops = 1;
-        ddp->deh_pad = 0;
+        ddp->deh_len_hops = htons(skb->len + (1<<10));
         ddp->deh_sum = 0;
 
         /*
@@ -170,7 +168,6 @@ static int ipddp_xmit(struct sk_buff *skb, struct net_device *dev)
         ddp->deh_sport = 72;
 
         *((__u8 *)(ddp+1)) = 22;                /* ddp type = IP */
-        *((__u16 *)ddp)=ntohs(*((__u16 *)ddp)); /* fix up length field */
 
         skb->protocol = htons(ETH_P_ATALK);     /* Protocol has changed */
 
diff --git a/include/linux/atalk.h b/include/linux/atalk.h
index 6ba3aa8a81f4..75b8baca08f3 100644
--- a/include/linux/atalk.h
+++ b/include/linux/atalk.h
@@ -88,15 +88,7 @@ static inline struct atalk_sock *at_sk(struct sock *sk)
 #include <asm/byteorder.h>
 
 struct ddpehdr {
-#ifdef __LITTLE_ENDIAN_BITFIELD
-        __u16   deh_len:10,
-                deh_hops:4,
-                deh_pad:2;
-#else
-        __u16   deh_pad:2,
-                deh_hops:4,
-                deh_len:10;
-#endif
+        __be16  deh_len_hops;   /* lower 10 bits are length, next 4 - hops */
         __be16  deh_sum;
         __be16  deh_dnet;
         __be16  deh_snet;
@@ -112,36 +104,6 @@ static __inline__ struct ddpehdr *ddp_hdr(struct sk_buff *skb)
         return (struct ddpehdr *)skb->h.raw;
 }
 
-/*
- *      Don't drop the struct into the struct above.  You'll get some
- *      surprise padding.
- */
-struct ddpebits {
-#ifdef __LITTLE_ENDIAN_BITFIELD
-        __u16   deh_len:10,
-                deh_hops:4,
-                deh_pad:2;
-#else
-        __u16   deh_pad:2,
-                deh_hops:4,
-                deh_len:10;
-#endif
-};
-
-/* Short form header */
-struct ddpshdr {
-#ifdef __LITTLE_ENDIAN_BITFIELD
-        __u16   dsh_len:10,
-                dsh_pad:6;
-#else
-        __u16   dsh_pad:6,
-                dsh_len:10;
-#endif
-        __u8    dsh_dport;
-        __u8    dsh_sport;
-        /* And netatalk apps expect to stick the type in themselves */
-};
-
 /* AppleTalk AARP headers */
 struct elapaarp {
         __be16  hw_type;
diff --git a/net/appletalk/ddp.c b/net/appletalk/ddp.c
index 96dc6bb52d14..708e2e0371af 100644
--- a/net/appletalk/ddp.c
+++ b/net/appletalk/ddp.c
@@ -1002,7 +1002,7 @@ static unsigned long atalk_sum_skb(const struct sk_buff *skb, int offset,
         return sum;
 }
 
-static unsigned short atalk_checksum(const struct sk_buff *skb, int len)
+static __be16 atalk_checksum(const struct sk_buff *skb, int len)
 {
         unsigned long sum;
 
@@ -1010,7 +1010,7 @@ static unsigned short atalk_checksum(const struct sk_buff *skb, int len)
         sum = atalk_sum_skb(skb, 4, len-4, 0);
 
         /* Use 0xFFFF for 0. 0 itself means none */
-        return sum ? htons((unsigned short)sum) : 0xFFFF;
+        return sum ? htons((unsigned short)sum) : htons(0xFFFF);
 }
 
 static struct proto ddp_proto = {
@@ -1289,7 +1289,7 @@ static int handle_ip_over_ddp(struct sk_buff *skb)
 #endif
 
 static void atalk_route_packet(struct sk_buff *skb, struct net_device *dev,
-                               struct ddpehdr *ddp, struct ddpebits *ddphv,
+                               struct ddpehdr *ddp, __u16 len_hops,
                                int origlen)
 {
         struct atalk_route *rt;
@@ -1317,10 +1317,12 @@ static void atalk_route_packet(struct sk_buff *skb, struct net_device *dev,
 
         /* Route the packet */
         rt = atrtr_find(&ta);
-        if (!rt || ddphv->deh_hops == DDP_MAXHOPS)
+        /* increment hops count */
+        len_hops += 1 << 10;
+        if (!rt || !(len_hops & (15 << 10)))
                 goto free_it;
+
         /* FIXME: use skb->cb to be able to use shared skbs */
-        ddphv->deh_hops++;
 
         /*
          * Route goes through another gateway, so set the target to the
@@ -1335,11 +1337,10 @@ static void atalk_route_packet(struct sk_buff *skb, struct net_device *dev,
         /* Fix up skb->len field */
         skb_trim(skb, min_t(unsigned int, origlen,
                             (rt->dev->hard_header_len +
-                             ddp_dl->header_length + ddphv->deh_len)));
+                             ddp_dl->header_length + (len_hops & 1023))));
 
-        /* Mend the byte order */
         /* FIXME: use skb->cb to be able to use shared skbs */
-        *((__u16 *)ddp) = ntohs(*((__u16 *)ddphv));
+        ddp->deh_len_hops = htons(len_hops);
 
         /*
          * Send the buffer onwards
@@ -1394,7 +1395,7 @@ static int atalk_rcv(struct sk_buff *skb, struct net_device *dev,
         struct atalk_iface *atif;
         struct sockaddr_at tosat;
         int origlen;
-        struct ddpebits ddphv;
+        __u16 len_hops;
 
         /* Don't mangle buffer if shared */
         if (!(skb = skb_share_check(skb, GFP_ATOMIC))) 
@@ -1406,16 +1407,11 @@ static int atalk_rcv(struct sk_buff *skb, struct net_device *dev,
 
         ddp = ddp_hdr(skb);
 
-        /*
-         *      Fix up the length field [Ok this is horrible but otherwise
-         *      I end up with unions of bit fields and messy bit field order
-         *      compiler/endian dependencies..]
-         */
-        *((__u16 *)&ddphv) = ntohs(*((__u16 *)ddp));
+        len_hops = ntohs(ddp->deh_len_hops);
 
         /* Trim buffer in case of stray trailing data */
         origlen = skb->len;
-        skb_trim(skb, min_t(unsigned int, skb->len, ddphv.deh_len));
+        skb_trim(skb, min_t(unsigned int, skb->len, len_hops & 1023));
 
         /*
          * Size check to see if ddp->deh_len was crap
@@ -1430,7 +1426,7 @@ static int atalk_rcv(struct sk_buff *skb, struct net_device *dev,
          * valid for net byte orders all over the networking code...
          */
         if (ddp->deh_sum &&
-            atalk_checksum(skb, ddphv.deh_len) != ddp->deh_sum)
+            atalk_checksum(skb, len_hops & 1023) != ddp->deh_sum)
                 /* Not a valid AppleTalk frame - dustbin time */
                 goto freeit;
 
@@ -1444,7 +1440,7 @@ static int atalk_rcv(struct sk_buff *skb, struct net_device *dev,
                 /* Not ours, so we route the packet via the correct
                  * AppleTalk iface
                  */
-                atalk_route_packet(skb, dev, ddp, &ddphv, origlen);
+                atalk_route_packet(skb, dev, ddp, len_hops, origlen);
                 goto out;
         }
 
@@ -1489,7 +1485,7 @@ static int ltalk_rcv(struct sk_buff *skb, struct net_device *dev,
                 /* Find our address */
                 struct atalk_addr *ap = atalk_find_dev_addr(dev);
 
-                if (!ap || skb->len < sizeof(struct ddpshdr))
+                if (!ap || skb->len < sizeof(__be16) || skb->len > 1023)
                         goto freeit;
 
                 /* Don't mangle buffer if shared */
@@ -1519,11 +1515,8 @@ static int ltalk_rcv(struct sk_buff *skb, struct net_device *dev,
                 /*
                  * Not sure about this bit...
                  */
-                ddp->deh_len   = skb->len;
-                ddp->deh_hops  = DDP_MAXHOPS;   /* Non routable, so force a drop
-                                                   if we slip up later */
-                /* Mend the byte order */
-                *((__u16 *)ddp) = htons(*((__u16 *)ddp));
+                /* Non routable, so force a drop if we slip up later */
+                ddp->deh_len_hops = htons(skb->len + (DDP_MAXHOPS << 10));
         }
         skb->h.raw = skb->data;
 
@@ -1622,16 +1615,7 @@ static int atalk_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr
         SOCK_DEBUG(sk, "SK %p: Begin build.\n", sk);
 
         ddp = (struct ddpehdr *)skb_put(skb, sizeof(struct ddpehdr));
-        ddp->deh_pad  = 0;
-        ddp->deh_hops = 0;
-        ddp->deh_len  = len + sizeof(*ddp);
-        /*
-         * Fix up the length field [Ok this is horrible but otherwise
-         * I end up with unions of bit fields and messy bit field order
-         * compiler/endian dependencies..
-         */
-        *((__u16 *)ddp) = ntohs(*((__u16 *)ddp));
-
+        ddp->deh_len_hops  = htons(len + sizeof(*ddp));
         ddp->deh_dnet  = usat->sat_addr.s_net;
         ddp->deh_snet  = at->src_net;
         ddp->deh_dnode = usat->sat_addr.s_node;
@@ -1712,8 +1696,8 @@ static int atalk_recvmsg(struct kiocb *iocb, struct socket *sock, struct msghdr
         struct sockaddr_at *sat = (struct sockaddr_at *)msg->msg_name;
         struct ddpehdr *ddp;
         int copied = 0;
+        int offset = 0;
         int err = 0;
-        struct ddpebits ddphv;
         struct sk_buff *skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT,
                                                 flags & MSG_DONTWAIT, &err);
         if (!skb)
@@ -1721,25 +1705,18 @@ static int atalk_recvmsg(struct kiocb *iocb, struct socket *sock, struct msghdr
 
         /* FIXME: use skb->cb to be able to use shared skbs */
         ddp = ddp_hdr(skb);
-        *((__u16 *)&ddphv) = ntohs(*((__u16 *)ddp));
+        copied = ntohs(ddp->deh_len_hops) & 1023;
 
-        if (sk->sk_type == SOCK_RAW) {
-                copied = ddphv.deh_len;
-                if (copied > size) {
-                        copied = size;
-                        msg->msg_flags |= MSG_TRUNC;
-                }
+        if (sk->sk_type != SOCK_RAW) {
+                offset = sizeof(*ddp);
+                copied -= offset;
+        }
 
-                err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
-        } else {
-                copied = ddphv.deh_len - sizeof(*ddp);
-                if (copied > size) {
-                        copied = size;
-                        msg->msg_flags |= MSG_TRUNC;
-                }
-                err = skb_copy_datagram_iovec(skb, sizeof(*ddp),
-                                              msg->msg_iov, copied);
+        if (copied > size) {
+                copied = size;
+                msg->msg_flags |= MSG_TRUNC;
         }
+        err = skb_copy_datagram_iovec(skb, offset, msg->msg_iov, copied);
 
         if (!err) {
                 if (sat) {