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isdn: isdn_ppp: Use SKB list facilities instead of home-grown implementation.

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Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2008-09-22 01:15:02 -07:00
parent 8fc5387cb8
commit 38783e6713
2 changed files with 189 additions and 163 deletions
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350
drivers/isdn/i4l/isdn_ppp.c
View file

@ -1533,8 +1533,10 @@ static int isdn_ppp_mp_bundle_array_init(void)
int sz = ISDN_MAX_CHANNELS*sizeof(ippp_bundle);
if( (isdn_ppp_bundle_arr = kzalloc(sz, GFP_KERNEL)) == NULL )
return -ENOMEM;
for( i = 0; i < ISDN_MAX_CHANNELS; i++ )
for (i = 0; i < ISDN_MAX_CHANNELS; i++) {
spin_lock_init(&isdn_ppp_bundle_arr[i].lock);
skb_queue_head_init(&isdn_ppp_bundle_arr[i].frags);
}
return 0;
}
@ -1567,7 +1569,7 @@ static int isdn_ppp_mp_init( isdn_net_local * lp, ippp_bundle * add_to )
if ((lp->netdev->pb = isdn_ppp_mp_bundle_alloc()) == NULL)
return -ENOMEM;
lp->next = lp->last = lp; /* nobody else in a queue */
lp->netdev->pb->frags = NULL;
skb_queue_head_init(&lp->netdev->pb->frags);
lp->netdev->pb->frames = 0;
lp->netdev->pb->seq = UINT_MAX;
}
@ -1579,28 +1581,29 @@ static int isdn_ppp_mp_init( isdn_net_local * lp, ippp_bundle * add_to )
static u32 isdn_ppp_mp_get_seq( int short_seq,
struct sk_buff * skb, u32 last_seq );
static struct sk_buff * isdn_ppp_mp_discard( ippp_bundle * mp,
struct sk_buff * from, struct sk_buff * to );
static void isdn_ppp_mp_reassembly( isdn_net_dev * net_dev, isdn_net_local * lp,
struct sk_buff * from, struct sk_buff * to );
static void isdn_ppp_mp_free_skb( ippp_bundle * mp, struct sk_buff * skb );
static void isdn_ppp_mp_discard(ippp_bundle *mp, struct sk_buff *from,
struct sk_buff *to);
static void isdn_ppp_mp_reassembly(isdn_net_dev *net_dev, isdn_net_local *lp,
struct sk_buff *from, struct sk_buff *to,
u32 lastseq);
static void isdn_ppp_mp_free_skb(ippp_bundle *mp, struct sk_buff *skb);
static void isdn_ppp_mp_print_recv_pkt( int slot, struct sk_buff * skb );
static void isdn_ppp_mp_receive(isdn_net_dev * net_dev, isdn_net_local * lp,
struct sk_buff *skb)
struct sk_buff *skb)
{
struct ippp_struct *is;
isdn_net_local * lpq;
ippp_bundle * mp;
isdn_mppp_stats * stats;
struct sk_buff * newfrag, * frag, * start, *nextf;
struct sk_buff *newfrag, *frag, *start, *nextf;
u32 newseq, minseq, thisseq;
isdn_mppp_stats *stats;
struct ippp_struct *is;
unsigned long flags;
isdn_net_local *lpq;
ippp_bundle *mp;
int slot;
spin_lock_irqsave(&net_dev->pb->lock, flags);
mp = net_dev->pb;
stats = &mp->stats;
mp = net_dev->pb;
stats = &mp->stats;
slot = lp->ppp_slot;
if (slot < 0 || slot >= ISDN_MAX_CHANNELS) {
printk(KERN_ERR "%s: lp->ppp_slot(%d)\n",
@ -1611,20 +1614,19 @@ static void isdn_ppp_mp_receive(isdn_net_dev * net_dev, isdn_net_local * lp,
return;
}
is = ippp_table[slot];
if( ++mp->frames > stats->max_queue_len )
if (++mp->frames > stats->max_queue_len)
stats->max_queue_len = mp->frames;
if (is->debug & 0x8)
isdn_ppp_mp_print_recv_pkt(lp->ppp_slot, skb);
newseq = isdn_ppp_mp_get_seq(is->mpppcfg & SC_IN_SHORT_SEQ,
skb, is->last_link_seqno);
newseq = isdn_ppp_mp_get_seq(is->mpppcfg & SC_IN_SHORT_SEQ,
skb, is->last_link_seqno);
/* if this packet seq # is less than last already processed one,
* toss it right away, but check for sequence start case first
*/
if( mp->seq > MP_LONGSEQ_MAX && (newseq & MP_LONGSEQ_MAXBIT) ) {
if (mp->seq > MP_LONGSEQ_MAX && (newseq & MP_LONGSEQ_MAXBIT)) {
mp->seq = newseq; /* the first packet: required for
* rfc1990 non-compliant clients --
* prevents constant packet toss */
@ -1634,7 +1636,7 @@ static void isdn_ppp_mp_receive(isdn_net_dev * net_dev, isdn_net_local * lp,
spin_unlock_irqrestore(&mp->lock, flags);
return;
}
/* find the minimum received sequence number over all links */
is->last_link_seqno = minseq = newseq;
for (lpq = net_dev->queue;;) {
@ -1655,22 +1657,31 @@ static void isdn_ppp_mp_receive(isdn_net_dev * net_dev, isdn_net_local * lp,
* packets */
newfrag = skb;
/* if this new fragment is before the first one, then enqueue it now. */
if ((frag = mp->frags) == NULL || MP_LT(newseq, MP_SEQ(frag))) {
newfrag->next = frag;
mp->frags = frag = newfrag;
newfrag = NULL;
}
/* Insert new fragment into the proper sequence slot. */
skb_queue_walk(&mp->frags, frag) {
if (MP_SEQ(frag) == newseq) {
isdn_ppp_mp_free_skb(mp, newfrag);
newfrag = NULL;
break;
}
if (MP_LT(newseq, MP_SEQ(frag))) {
__skb_queue_before(&mp->frags, frag, newfrag);
newfrag = NULL;
break;
}
}
if (newfrag)
__skb_queue_tail(&mp->frags, newfrag);
start = MP_FLAGS(frag) & MP_BEGIN_FRAG &&
MP_SEQ(frag) == mp->seq ? frag : NULL;
frag = skb_peek(&mp->frags);
start = ((MP_FLAGS(frag) & MP_BEGIN_FRAG) &&
(MP_SEQ(frag) == mp->seq)) ? frag : NULL;
if (!start)
goto check_overflow;
/*
* main fragment traversing loop
/* main fragment traversing loop
*
* try to accomplish several tasks:
* - insert new fragment into the proper sequence slot (once that's done
* newfrag will be set to NULL)
* - reassemble any complete fragment sequence (non-null 'start'
* indicates there is a continguous sequence present)
* - discard any incomplete sequences that are below minseq -- due
@ -1679,71 +1690,46 @@ static void isdn_ppp_mp_receive(isdn_net_dev * net_dev, isdn_net_local * lp,
* come to complete such sequence and it should be discarded
*
* loop completes when we accomplished the following tasks:
* - new fragment is inserted in the proper sequence ('newfrag' is
* set to NULL)
* - we hit a gap in the sequence, so no reassembly/processing is
* possible ('start' would be set to NULL)
*
* algorithm for this code is derived from code in the book
* 'PPP Design And Debugging' by James Carlson (Addison-Wesley)
*/
while (start != NULL || newfrag != NULL) {
skb_queue_walk_safe(&mp->frags, frag, nextf) {
thisseq = MP_SEQ(frag);
thisseq = MP_SEQ(frag);
nextf = frag->next;
/* drop any duplicate fragments */
if (newfrag != NULL && thisseq == newseq) {
isdn_ppp_mp_free_skb(mp, newfrag);
newfrag = NULL;
}
/* insert new fragment before next element if possible. */
if (newfrag != NULL && (nextf == NULL ||
MP_LT(newseq, MP_SEQ(nextf)))) {
newfrag->next = nextf;
frag->next = nextf = newfrag;
newfrag = NULL;
}
if (start != NULL) {
/* check for misplaced start */
if (start != frag && (MP_FLAGS(frag) & MP_BEGIN_FRAG)) {
printk(KERN_WARNING"isdn_mppp(seq %d): new "
"BEGIN flag with no prior END", thisseq);
stats->seqerrs++;
stats->frame_drops++;
start = isdn_ppp_mp_discard(mp, start,frag);
nextf = frag->next;
}
} else if (MP_LE(thisseq, minseq)) {
if (MP_FLAGS(frag) & MP_BEGIN_FRAG)
/* check for misplaced start */
if (start != frag && (MP_FLAGS(frag) & MP_BEGIN_FRAG)) {
printk(KERN_WARNING"isdn_mppp(seq %d): new "
"BEGIN flag with no prior END", thisseq);
stats->seqerrs++;
stats->frame_drops++;
isdn_ppp_mp_discard(mp, start, frag);
start = frag;
} else if (MP_LE(thisseq, minseq)) {
if (MP_FLAGS(frag) & MP_BEGIN_FRAG)
start = frag;
else {
else {
if (MP_FLAGS(frag) & MP_END_FRAG)
stats->frame_drops++;
if( mp->frags == frag )
mp->frags = nextf;
stats->frame_drops++;
__skb_unlink(skb, &mp->frags);
isdn_ppp_mp_free_skb(mp, frag);
frag = nextf;
continue;
}
}
}
/* if start is non-null and we have end fragment, then
* we have full reassembly sequence -- reassemble
* and process packet now
*/
if (start != NULL && (MP_FLAGS(frag) & MP_END_FRAG)) {
minseq = mp->seq = (thisseq+1) & MP_LONGSEQ_MASK;
/* Reassemble the packet then dispatch it */
isdn_ppp_mp_reassembly(net_dev, lp, start, nextf);
start = NULL;
frag = NULL;
mp->frags = nextf;
}
/* if we have end fragment, then we have full reassembly
* sequence -- reassemble and process packet now
*/
if (MP_FLAGS(frag) & MP_END_FRAG) {
minseq = mp->seq = (thisseq+1) & MP_LONGSEQ_MASK;
/* Reassemble the packet then dispatch it */
isdn_ppp_mp_reassembly(net_dev, lp, start, frag, thisseq);
start = NULL;
frag = NULL;
}
/* check if need to update start pointer: if we just
* reassembled the packet and sequence is contiguous
@ -1754,26 +1740,25 @@ static void isdn_ppp_mp_receive(isdn_net_dev * net_dev, isdn_net_local * lp,
* below low watermark and set start to the next frag or
* clear start ptr.
*/
if (nextf != NULL &&
if (nextf != (struct sk_buff *)&mp->frags &&
((thisseq+1) & MP_LONGSEQ_MASK) == MP_SEQ(nextf)) {
/* if we just reassembled and the next one is here,
* then start another reassembly. */
if (frag == NULL) {
/* if we just reassembled and the next one is here,
* then start another reassembly.
*/
if (frag == NULL) {
if (MP_FLAGS(nextf) & MP_BEGIN_FRAG)
start = nextf;
else
{
printk(KERN_WARNING"isdn_mppp(seq %d):"
" END flag with no following "
"BEGIN", thisseq);
start = nextf;
else {
printk(KERN_WARNING"isdn_mppp(seq %d):"
" END flag with no following "
"BEGIN", thisseq);
stats->seqerrs++;
}
}
} else {
if ( nextf != NULL && frag != NULL &&
MP_LT(thisseq, minseq)) {
} else {
if (nextf != (struct sk_buff *)&mp->frags &&
frag != NULL &&
MP_LT(thisseq, minseq)) {
/* we've got a break in the sequence
* and we not at the end yet
* and we did not just reassembled
@ -1782,41 +1767,39 @@ static void isdn_ppp_mp_receive(isdn_net_dev * net_dev, isdn_net_local * lp,
* discard all the frames below low watermark
* and start over */
stats->frame_drops++;
mp->frags = isdn_ppp_mp_discard(mp,start,nextf);
isdn_ppp_mp_discard(mp, start, nextf);
}
/* break in the sequence, no reassembly */
start = NULL;
}
frag = nextf;
} /* while -- main loop */
if (mp->frags == NULL)
mp->frags = frag;
start = NULL;
}
if (!start)
break;
}
check_overflow:
/* rather straighforward way to deal with (not very) possible
* queue overflow */
* queue overflow
*/
if (mp->frames > MP_MAX_QUEUE_LEN) {
stats->overflows++;
while (mp->frames > MP_MAX_QUEUE_LEN) {
frag = mp->frags->next;
isdn_ppp_mp_free_skb(mp, mp->frags);
mp->frags = frag;
skb_queue_walk_safe(&mp->frags, frag, nextf) {
if (mp->frames <= MP_MAX_QUEUE_LEN)
break;
__skb_unlink(frag, &mp->frags);
isdn_ppp_mp_free_skb(mp, frag);
}
}
spin_unlock_irqrestore(&mp->lock, flags);
}
static void isdn_ppp_mp_cleanup( isdn_net_local * lp )
static void isdn_ppp_mp_cleanup(isdn_net_local *lp)
{
struct sk_buff * frag = lp->netdev->pb->frags;
struct sk_buff * nextfrag;
while( frag ) {
nextfrag = frag->next;
isdn_ppp_mp_free_skb(lp->netdev->pb, frag);
frag = nextfrag;
struct sk_buff *skb, *tmp;
skb_queue_walk_safe(&lp->netdev->pb->frags, skb, tmp) {
__skb_unlink(skb, &lp->netdev->pb->frags);
isdn_ppp_mp_free_skb(lp->netdev->pb, skb);
}
lp->netdev->pb->frags = NULL;
}
static u32 isdn_ppp_mp_get_seq( int short_seq,
@ -1853,72 +1836,115 @@ static u32 isdn_ppp_mp_get_seq( int short_seq,
return seq;
}
struct sk_buff * isdn_ppp_mp_discard( ippp_bundle * mp,
struct sk_buff * from, struct sk_buff * to )
static void isdn_ppp_mp_discard(ippp_bundle *mp, struct sk_buff *from,
struct sk_buff *to)
{
if( from )
while (from != to) {
struct sk_buff * next = from->next;
isdn_ppp_mp_free_skb(mp, from);
from = next;
if (from) {
struct sk_buff *skb, *tmp;
int freeing = 0;
skb_queue_walk_safe(&mp->frags, skb, tmp) {
if (skb == to)
break;
if (skb == from)
freeing = 1;
if (!freeing)
continue;
__skb_unlink(skb, &mp->frags);
isdn_ppp_mp_free_skb(mp, skb);
}
return from;
}
}
void isdn_ppp_mp_reassembly( isdn_net_dev * net_dev, isdn_net_local * lp,
struct sk_buff * from, struct sk_buff * to )
static unsigned int calc_tot_len(struct sk_buff_head *queue,
struct sk_buff *from, struct sk_buff *to)
{
ippp_bundle * mp = net_dev->pb;
int proto;
struct sk_buff * skb;
unsigned int tot_len = 0;
struct sk_buff *skb;
int found_start = 0;
skb_queue_walk(queue, skb) {
if (skb == from)
found_start = 1;
if (!found_start)
continue;
tot_len += skb->len - MP_HEADER_LEN;
if (skb == to)
break;
}
return tot_len;
}
/* Reassemble packet using fragments in the reassembly queue from
* 'from' until 'to', inclusive.
*/
static void isdn_ppp_mp_reassembly(isdn_net_dev *net_dev, isdn_net_local *lp,
struct sk_buff *from, struct sk_buff *to,
u32 lastseq)
{
ippp_bundle *mp = net_dev->pb;
unsigned int tot_len;
struct sk_buff *skb;
int proto;
if (lp->ppp_slot < 0 || lp->ppp_slot >= ISDN_MAX_CHANNELS) {
printk(KERN_ERR "%s: lp->ppp_slot(%d) out of range\n",
__func__, lp->ppp_slot);
return;
}
if( MP_FLAGS(from) == (MP_BEGIN_FRAG | MP_END_FRAG) ) {
if( ippp_table[lp->ppp_slot]->debug & 0x40 )
tot_len = calc_tot_len(&mp->frags, from, to);
if (MP_FLAGS(from) == (MP_BEGIN_FRAG | MP_END_FRAG)) {
if (ippp_table[lp->ppp_slot]->debug & 0x40)
printk(KERN_DEBUG "isdn_mppp: reassembly: frame %d, "
"len %d\n", MP_SEQ(from), from->len );
"len %d\n", MP_SEQ(from), from->len);
skb = from;
skb_pull(skb, MP_HEADER_LEN);
__skb_unlink(skb, &mp->frags);
mp->frames--;
} else {
struct sk_buff * frag;
int n;
struct sk_buff *walk, *tmp;
int found_start = 0;
for(tot_len=n=0, frag=from; frag != to; frag=frag->next, n++)
tot_len += frag->len - MP_HEADER_LEN;
if( ippp_table[lp->ppp_slot]->debug & 0x40 )
if (ippp_table[lp->ppp_slot]->debug & 0x40)
printk(KERN_DEBUG"isdn_mppp: reassembling frames %d "
"to %d, len %d\n", MP_SEQ(from),
(MP_SEQ(from)+n-1) & MP_LONGSEQ_MASK, tot_len );
if( (skb = dev_alloc_skb(tot_len)) == NULL ) {
"to %d, len %d\n", MP_SEQ(from), lastseq,
tot_len);
skb = dev_alloc_skb(tot_len);
if (!skb)
printk(KERN_ERR "isdn_mppp: cannot allocate sk buff "
"of size %d\n", tot_len);
isdn_ppp_mp_discard(mp, from, to);
return;
}
"of size %d\n", tot_len);
while( from != to ) {
unsigned int len = from->len - MP_HEADER_LEN;
found_start = 0;
skb_queue_walk_safe(&mp->frags, walk, tmp) {
if (walk == from)
found_start = 1;
if (!found_start)
continue;
skb_copy_from_linear_data_offset(from, MP_HEADER_LEN,
skb_put(skb,len),
len);
frag = from->next;
isdn_ppp_mp_free_skb(mp, from);
from = frag;
if (skb) {
unsigned int len = walk->len - MP_HEADER_LEN;
skb_copy_from_linear_data_offset(walk, MP_HEADER_LEN,
skb_put(skb, len),
len);
}
__skb_unlink(walk, &mp->frags);
isdn_ppp_mp_free_skb(mp, walk);
if (walk == to)
break;
}
}
if (!skb)
return;
proto = isdn_ppp_strip_proto(skb);
isdn_ppp_push_higher(net_dev, lp, skb, proto);
}
static void isdn_ppp_mp_free_skb(ippp_bundle * mp, struct sk_buff * skb)
static void isdn_ppp_mp_free_skb(ippp_bundle *mp, struct sk_buff *skb)
{
dev_kfree_skb(skb);
mp->frames--;

2
include/linux/isdn_ppp.h
View file

@ -157,7 +157,7 @@ typedef struct {
typedef struct {
int mp_mrru; /* unused */
struct sk_buff * frags; /* fragments sl list -- use skb->next */
struct sk_buff_head frags; /* fragments sl list */
long frames; /* number of frames in the frame list */
unsigned int seq; /* last processed packet seq #: any packets
* with smaller seq # will be dropped