ppp: Use a real SKB control block in fragmentation engine.
authorDavid S. Miller <davem@davemloft.net>
Tue, 5 Oct 2010 08:36:52 +0000 (01:36 -0700)
committerDavid S. Miller <davem@davemloft.net>
Tue, 5 Oct 2010 08:36:52 +0000 (01:36 -0700)
Do this instead of subverting fields in skb proper.

The macros that could very easily match variable or function
names were also just asking for trouble.

Signed-off-by: David S. Miller <davem@davemloft.net>
drivers/net/ppp_generic.c

index 736b91703b3e11578eda930e7b119a06f96c0fc6..866e221643abcd3368deebd447e7cf5e807c26d8 100644 (file)
@@ -1547,9 +1547,11 @@ ppp_channel_push(struct channel *pch)
  * Receive-side routines.
  */
 
-/* misuse a few fields of the skb for MP reconstruction */
-#define sequence       priority
-#define BEbits         cb[0]
+struct ppp_mp_skb_parm {
+       u32             sequence;
+       u8              BEbits;
+};
+#define PPP_MP_CB(skb) ((struct ppp_mp_skb_parm *)((skb)->cb))
 
 static inline void
 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
@@ -1878,13 +1880,13 @@ ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
                seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
                mask = 0xffffff;
        }
-       skb->BEbits = skb->data[2];
+       PPP_MP_CB(skb)->BEbits = skb->data[2];
        skb_pull(skb, mphdrlen);        /* pull off PPP and MP headers */
 
        /*
         * Do protocol ID decompression on the first fragment of each packet.
         */
-       if ((skb->BEbits & B) && (skb->data[0] & 1))
+       if ((PPP_MP_CB(skb)->BEbits & B) && (skb->data[0] & 1))
                *skb_push(skb, 1) = 0;
 
        /*
@@ -1896,7 +1898,7 @@ ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
                seq += mask + 1;
        else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
                seq -= mask + 1;        /* should never happen */
-       skb->sequence = seq;
+       PPP_MP_CB(skb)->sequence = seq;
        pch->lastseq = seq;
 
        /*
@@ -1932,8 +1934,8 @@ ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
           before the start of the queue. */
        if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN) {
                struct sk_buff *mskb = skb_peek(&ppp->mrq);
-               if (seq_before(ppp->minseq, mskb->sequence))
-                       ppp->minseq = mskb->sequence;
+               if (seq_before(ppp->minseq, PPP_MP_CB(mskb)->sequence))
+                       ppp->minseq = PPP_MP_CB(mskb)->sequence;
        }
 
        /* Pull completed packets off the queue and receive them. */
@@ -1963,12 +1965,12 @@ ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
 {
        struct sk_buff *p;
        struct sk_buff_head *list = &ppp->mrq;
-       u32 seq = skb->sequence;
+       u32 seq = PPP_MP_CB(skb)->sequence;
 
        /* N.B. we don't need to lock the list lock because we have the
           ppp unit receive-side lock. */
        skb_queue_walk(list, p) {
-               if (seq_before(seq, p->sequence))
+               if (seq_before(seq, PPP_MP_CB(p)->sequence))
                        break;
        }
        __skb_queue_before(list, p, skb);
@@ -1997,22 +1999,22 @@ ppp_mp_reconstruct(struct ppp *ppp)
        tail = NULL;
        for (p = head; p != (struct sk_buff *) list; p = next) {
                next = p->next;
-               if (seq_before(p->sequence, seq)) {
+               if (seq_before(PPP_MP_CB(p)->sequence, seq)) {
                        /* this can't happen, anyway ignore the skb */
                        printk(KERN_ERR "ppp_mp_reconstruct bad seq %u < %u\n",
-                              p->sequence, seq);
+                              PPP_MP_CB(p)->sequence, seq);
                        head = next;
                        continue;
                }
-               if (p->sequence != seq) {
+               if (PPP_MP_CB(p)->sequence != seq) {
                        /* Fragment `seq' is missing.  If it is after
                           minseq, it might arrive later, so stop here. */
                        if (seq_after(seq, minseq))
                                break;
                        /* Fragment `seq' is lost, keep going. */
                        lost = 1;
-                       seq = seq_before(minseq, p->sequence)?
-                               minseq + 1: p->sequence;
+                       seq = seq_before(minseq, PPP_MP_CB(p)->sequence)?
+                               minseq + 1: PPP_MP_CB(p)->sequence;
                        next = p;
                        continue;
                }
@@ -2026,7 +2028,7 @@ ppp_mp_reconstruct(struct ppp *ppp)
                 */
 
                /* B bit set indicates this fragment starts a packet */
-               if (p->BEbits & B) {
+               if (PPP_MP_CB(p)->BEbits & B) {
                        head = p;
                        lost = 0;
                        len = 0;
@@ -2035,7 +2037,8 @@ ppp_mp_reconstruct(struct ppp *ppp)
                len += p->len;
 
                /* Got a complete packet yet? */
-               if (lost == 0 && (p->BEbits & E) && (head->BEbits & B)) {
+               if (lost == 0 && (PPP_MP_CB(p)->BEbits & E) &&
+                   (PPP_MP_CB(head)->BEbits & B)) {
                        if (len > ppp->mrru + 2) {
                                ++ppp->dev->stats.rx_length_errors;
                                printk(KERN_DEBUG "PPP: reconstructed packet"
@@ -2061,7 +2064,7 @@ ppp_mp_reconstruct(struct ppp *ppp)
                 * and we haven't found a complete valid packet yet,
                 * we can discard up to and including this fragment.
                 */
-               if (p->BEbits & E)
+               if (PPP_MP_CB(p)->BEbits & E)
                        head = next;
 
                ++seq;
@@ -2071,10 +2074,11 @@ ppp_mp_reconstruct(struct ppp *ppp)
        if (tail != NULL) {
                /* If we have discarded any fragments,
                   signal a receive error. */
-               if (head->sequence != ppp->nextseq) {
+               if (PPP_MP_CB(head)->sequence != ppp->nextseq) {
                        if (ppp->debug & 1)
                                printk(KERN_DEBUG "  missed pkts %u..%u\n",
-                                      ppp->nextseq, head->sequence-1);
+                                      ppp->nextseq,
+                                      PPP_MP_CB(head)->sequence-1);
                        ++ppp->dev->stats.rx_dropped;
                        ppp_receive_error(ppp);
                }
@@ -2083,7 +2087,7 @@ ppp_mp_reconstruct(struct ppp *ppp)
                        /* copy to a single skb */
                        for (p = head; p != tail->next; p = p->next)
                                skb_copy_bits(p, 0, skb_put(skb, p->len), p->len);
-               ppp->nextseq = tail->sequence + 1;
+               ppp->nextseq = PPP_MP_CB(tail)->sequence + 1;
                head = tail->next;
        }