static void ip4_frag_init(struct inet_frag_queue *q, void *a)
{
struct ipq *qp = container_of(q, struct ipq, q);
struct netns_ipv4 *ipv4 = container_of(q->net, struct netns_ipv4,
frags);
struct net *net = container_of(ipv4, struct net, ipv4);
struct ip4_create_arg *arg = a;
qp->protocol = arg->iph->protocol;
qp->id = arg->iph->id;
qp->ecn = ip4_frag_ecn(arg->iph->tos);
qp->saddr = arg->iph->saddr;
qp->daddr = arg->iph->daddr;
qp->user = arg->user;
qp->peer = sysctl_ipfrag_max_dist ?
inet_getpeer_v4(net->ipv4.peers, arg->iph->saddr, 1) : NULL;
}
/* Add new segment to existing queue. */
static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb)
{
struct sk_buff *prev, *next;
struct net_device *dev;
int flags, offset;
int ihl, end;
int err = -ENOENT;
u8 ecn;
if (qp->q.last_in & INET_FRAG_COMPLETE)
goto err;
if (!(IPCB(skb)->flags & IPSKB_FRAG_COMPLETE) &&
unlikely(ip_frag_too_far(qp)) &&
unlikely(err = ip_frag_reinit(qp))) {
ipq_kill(qp);
goto err;
}
ecn = ip4_frag_ecn(ip_hdr(skb)->tos);
offset = ntohs(ip_hdr(skb)->frag_off);
flags = offset & ~IP_OFFSET;
offset &= IP_OFFSET;
offset <<= 3; /* offset is in 8-byte chunks */
ihl = ip_hdrlen(skb);
/* Determine the position of this fragment. */
end = offset + skb->len - skb_network_offset(skb) - ihl;
err = -EINVAL;
/* Is this the final fragment? */
if ((flags & IP_MF) == 0) {
/* If we already have some bits beyond end
* or have different end, the segment is corrupted.
*/
if (end < qp->q.len ||
((qp->q.last_in & INET_FRAG_LAST_IN) && end != qp->q.len))
goto err;
qp->q.last_in |= INET_FRAG_LAST_IN;
qp->q.len = end;
} else {
if (end&7) {
end &= ~7;
if (skb->ip_summed != CHECKSUM_UNNECESSARY)
skb->ip_summed = CHECKSUM_NONE;
}
if (end > qp->q.len) {
/* Some bits beyond end -> corruption. */
if (qp->q.last_in & INET_FRAG_LAST_IN)
goto err;
qp->q.len = end;
}
}
if (end == offset)
goto err;
err = -ENOMEM;
if (!pskb_pull(skb, skb_network_offset(skb) + ihl))
goto err;
err = pskb_trim_rcsum(skb, end - offset);
if (err)
goto err;
/* Find out which fragments are in front and at the back of us
* in the chain of fragments so far. We must know where to put
* this fragment, right?
*/
prev = qp->q.fragments_tail;
if (!prev || FRAG_CB(prev)->offset < offset) {
next = NULL;
goto found;
}
prev = NULL;
for (next = qp->q.fragments; next != NULL; next = next->next) {
if (FRAG_CB(next)->offset >= offset)
break; /* bingo! */
prev = next;
}
found:
/* We found where to put this one. Check for overlap with
* preceding fragment, and, if needed, align things so that
* any overlaps are eliminated.
*/
if (prev) {
int i = (FRAG_CB(prev)->offset + prev->len) - offset;
if (i > 0) {
offset += i;
err = -EINVAL;
if (end <= offset)
goto err;
err = -ENOMEM;
if (!pskb_pull(skb, i))
goto err;
if (skb->ip_summed != CHECKSUM_UNNECESSARY)
skb->ip_summed = CHECKSUM_NONE;
}
}
err = -ENOMEM;
while (next && FRAG_CB(next)->offset < end) {
int i = end - FRAG_CB(next)->offset; /* overlap is 'i' bytes */
if (i < next->len) {
/* Eat head of the next overlapped fragment
* and leave the loop. The next ones cannot overlap.
*/
if (!pskb_pull(next, i))
goto err;
FRAG_CB(next)->offset += i;
qp->q.meat -= i;
if (next->ip_summed != CHECKSUM_UNNECESSARY)
next->ip_summed = CHECKSUM_NONE;
break;
} else {
struct sk_buff *free_it = next;
/* Old fragment is completely overridden with
* new one drop it.
*/
next = next->next;
if (prev)
prev->next = next;
else
qp->q.fragments = next;
qp->q.meat -= free_it->len;
sub_frag_mem_limit(&qp->q, free_it->truesize);
kfree_skb(free_it);
}
}
FRAG_CB(skb)->offset = offset;
/* Insert this fragment in the chain of fragments. */
skb->next = next;
if (!next)
qp->q.fragments_tail = skb;
if (prev)
prev->next = skb;
else
qp->q.fragments = skb;
dev = skb->dev;
if (dev) {
qp->iif = dev->ifindex;
skb->dev = NULL;
}
qp->q.stamp = skb->tstamp;
qp->q.meat += skb->len;
qp->ecn |= ecn;
add_frag_mem_limit(&qp->q, skb->truesize);
if (offset == 0)
qp->q.last_in |= INET_FRAG_FIRST_IN;
if (ip_hdr(skb)->frag_off & htons(IP_DF) &&
skb->len + ihl > qp->q.max_size)
qp->q.max_size = skb->len + ihl;
if (qp->q.last_in == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) &&
qp->q.meat == qp->q.len) {
unsigned long orefdst = skb->_skb_refdst;
skb->_skb_refdst = 0UL;
err = ip_frag_reasm(qp, prev, dev);
skb->_skb_refdst = orefdst;
return err;
}
skb_dst_drop(skb);
inet_frag_lru_move(&qp->q);
return -EINPROGRESS;
err:
kfree_skb(skb);
return err;
}
static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb)
{
struct sk_buff *prev, *next;
struct net_device *dev;
int flags, offset;
int ihl, end;
int err = -ENOENT;
u8 ecn;
if (qp->q.last_in & INET_FRAG_COMPLETE)
goto err;
if (!(IPCB(skb)->flags & IPSKB_FRAG_COMPLETE) &&
unlikely(ip_frag_too_far(qp)) &&
unlikely(err = ip_frag_reinit(qp))) {
ipq_kill(qp);
goto err;
}
ecn = ip4_frag_ecn(ip_hdr(skb)->tos);
offset = ntohs(ip_hdr(skb)->frag_off);
flags = offset & ~IP_OFFSET;
offset &= IP_OFFSET;
offset <<= 3;
ihl = ip_hdrlen(skb);
end = offset + skb->len - ihl;
err = -EINVAL;
if ((flags & IP_MF) == 0) {
if (end < qp->q.len ||
((qp->q.last_in & INET_FRAG_LAST_IN) && end != qp->q.len))
goto err;
qp->q.last_in |= INET_FRAG_LAST_IN;
qp->q.len = end;
} else {
if (end&7) {
end &= ~7;
if (skb->ip_summed != CHECKSUM_UNNECESSARY)
skb->ip_summed = CHECKSUM_NONE;
}
if (end > qp->q.len) {
if (qp->q.last_in & INET_FRAG_LAST_IN)
goto err;
qp->q.len = end;
}
}
if (end == offset)
goto err;
err = -ENOMEM;
if (pskb_pull(skb, ihl) == NULL)
goto err;
err = pskb_trim_rcsum(skb, end - offset);
if (err)
goto err;
prev = qp->q.fragments_tail;
if (!prev || FRAG_CB(prev)->offset < offset) {
next = NULL;
goto found;
}
prev = NULL;
for (next = qp->q.fragments; next != NULL; next = next->next) {
if (FRAG_CB(next)->offset >= offset)
break;
prev = next;
}
found:
if (prev) {
int i = (FRAG_CB(prev)->offset + prev->len) - offset;
if (i > 0) {
offset += i;
err = -EINVAL;
if (end <= offset)
goto err;
err = -ENOMEM;
if (!pskb_pull(skb, i))
goto err;
if (skb->ip_summed != CHECKSUM_UNNECESSARY)
skb->ip_summed = CHECKSUM_NONE;
}
}
err = -ENOMEM;
while (next && FRAG_CB(next)->offset < end) {
int i = end - FRAG_CB(next)->offset;
if (i < next->len) {
if (!pskb_pull(next, i))
goto err;
FRAG_CB(next)->offset += i;
qp->q.meat -= i;
if (next->ip_summed != CHECKSUM_UNNECESSARY)
next->ip_summed = CHECKSUM_NONE;
break;
} else {
struct sk_buff *free_it = next;
next = next->next;
if (prev)
prev->next = next;
else
qp->q.fragments = next;
qp->q.meat -= free_it->len;
frag_kfree_skb(qp->q.net, free_it);
}
}
FRAG_CB(skb)->offset = offset;
skb->next = next;
if (!next)
qp->q.fragments_tail = skb;
if (prev)
prev->next = skb;
else
qp->q.fragments = skb;
dev = skb->dev;
if (dev) {
qp->iif = dev->ifindex;
skb->dev = NULL;
}
qp->q.stamp = skb->tstamp;
qp->q.meat += skb->len;
qp->ecn |= ecn;
atomic_add(skb->truesize, &qp->q.net->mem);
if (offset == 0)
qp->q.last_in |= INET_FRAG_FIRST_IN;
if (qp->q.last_in == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) &&
qp->q.meat == qp->q.len) {
unsigned long orefdst = skb->_skb_refdst;
skb->_skb_refdst = 0UL;
err = ip_frag_reasm(qp, prev, dev);
skb->_skb_refdst = orefdst;
return err;
}
skb_dst_drop(skb);
write_lock(&ip4_frags.lock);
list_move_tail(&qp->q.lru_list, &qp->q.net->lru_list);
write_unlock(&ip4_frags.lock);
return -EINPROGRESS;
err:
kfree_skb(skb);
return err;
}
/* Add new segment to existing queue. */
static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb)
{
struct net *net = container_of(qp->q.net, struct net, ipv4.frags);
struct rb_node **rbn, *parent;
struct sk_buff *skb1, *prev_tail;
struct net_device *dev;
unsigned int fragsize;
int flags, offset;
int ihl, end;
int err = -ENOENT;
u8 ecn;
if (qp->q.flags & INET_FRAG_COMPLETE)
goto err;
if (!(IPCB(skb)->flags & IPSKB_FRAG_COMPLETE) &&
unlikely(ip_frag_too_far(qp)) &&
unlikely(err = ip_frag_reinit(qp))) {
ipq_kill(qp);
goto err;
}
ecn = ip4_frag_ecn(ip_hdr(skb)->tos);
offset = ntohs(ip_hdr(skb)->frag_off);
flags = offset & ~IP_OFFSET;
offset &= IP_OFFSET;
offset <<= 3; /* offset is in 8-byte chunks */
ihl = ip_hdrlen(skb);
/* Determine the position of this fragment. */
end = offset + skb->len - skb_network_offset(skb) - ihl;
err = -EINVAL;
/* Is this the final fragment? */
if ((flags & IP_MF) == 0) {
/* If we already have some bits beyond end
* or have different end, the segment is corrupted.
*/
if (end < qp->q.len ||
((qp->q.flags & INET_FRAG_LAST_IN) && end != qp->q.len))
goto err;
qp->q.flags |= INET_FRAG_LAST_IN;
qp->q.len = end;
} else {
if (end&7) {
end &= ~7;
if (skb->ip_summed != CHECKSUM_UNNECESSARY)
skb->ip_summed = CHECKSUM_NONE;
}
if (end > qp->q.len) {
/* Some bits beyond end -> corruption. */
if (qp->q.flags & INET_FRAG_LAST_IN)
goto err;
qp->q.len = end;
}
}
if (end == offset)
goto err;
err = -ENOMEM;
if (!pskb_pull(skb, skb_network_offset(skb) + ihl))
goto err;
err = pskb_trim_rcsum(skb, end - offset);
if (err)
goto err;
/* Note : skb->rbnode and skb->dev share the same location. */
dev = skb->dev;
/* Makes sure compiler wont do silly aliasing games */
barrier();
/* RFC5722, Section 4, amended by Errata ID : 3089
* When reassembling an IPv6 datagram, if
* one or more its constituent fragments is determined to be an
* overlapping fragment, the entire datagram (and any constituent
* fragments) MUST be silently discarded.
*
* We do the same here for IPv4 (and increment an snmp counter).
*/
/* Find out where to put this fragment. */
prev_tail = qp->q.fragments_tail;
if (!prev_tail)
ip4_frag_create_run(&qp->q, skb); /* First fragment. */
else if (prev_tail->ip_defrag_offset + prev_tail->len < end) {
/* This is the common case: skb goes to the end. */
/* Detect and discard overlaps. */
if (offset < prev_tail->ip_defrag_offset + prev_tail->len)
goto discard_qp;
if (offset == prev_tail->ip_defrag_offset + prev_tail->len)
ip4_frag_append_to_last_run(&qp->q, skb);
else
ip4_frag_create_run(&qp->q, skb);
} else {
/* Binary search. Note that skb can become the first fragment,
* but not the last (covered above).
*/
rbn = &qp->q.rb_fragments.rb_node;
do {
parent = *rbn;
skb1 = rb_to_skb(parent);
if (end <= skb1->ip_defrag_offset)
rbn = &parent->rb_left;
else if (offset >= skb1->ip_defrag_offset +
FRAG_CB(skb1)->frag_run_len)
rbn = &parent->rb_right;
else /* Found an overlap with skb1. */
goto discard_qp;
} while (*rbn);
/* Here we have parent properly set, and rbn pointing to
* one of its NULL left/right children. Insert skb.
*/
ip4_frag_init_run(skb);
rb_link_node(&skb->rbnode, parent, rbn);
rb_insert_color(&skb->rbnode, &qp->q.rb_fragments);
}
if (dev)
qp->iif = dev->ifindex;
skb->ip_defrag_offset = offset;
qp->q.stamp = skb->tstamp;
qp->q.meat += skb->len;
qp->ecn |= ecn;
add_frag_mem_limit(qp->q.net, skb->truesize);
if (offset == 0)
qp->q.flags |= INET_FRAG_FIRST_IN;
fragsize = skb->len + ihl;
if (fragsize > qp->q.max_size)
qp->q.max_size = fragsize;
if (ip_hdr(skb)->frag_off & htons(IP_DF) &&
fragsize > qp->max_df_size)
qp->max_df_size = fragsize;
if (qp->q.flags == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) &&
qp->q.meat == qp->q.len) {
unsigned long orefdst = skb->_skb_refdst;
skb->_skb_refdst = 0UL;
err = ip_frag_reasm(qp, skb, prev_tail, dev);
skb->_skb_refdst = orefdst;
return err;
}
skb_dst_drop(skb);
return -EINPROGRESS;
discard_qp:
inet_frag_kill(&qp->q);
err = -EINVAL;
__IP_INC_STATS(net, IPSTATS_MIB_REASM_OVERLAPS);
err:
kfree_skb(skb);
return err;
}
