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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /net/ipv4/inet_fragment.c
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'net/ipv4/inet_fragment.c')
-rw-r--r--net/ipv4/inet_fragment.c602
1 files changed, 602 insertions, 0 deletions
diff --git a/net/ipv4/inet_fragment.c b/net/ipv4/inet_fragment.c
new file mode 100644
index 000000000..c9f9ac501
--- /dev/null
+++ b/net/ipv4/inet_fragment.c
@@ -0,0 +1,602 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * inet fragments management
+ *
+ * Authors: Pavel Emelyanov <xemul@openvz.org>
+ * Started as consolidation of ipv4/ip_fragment.c,
+ * ipv6/reassembly. and ipv6 nf conntrack reassembly
+ */
+
+#include <linux/list.h>
+#include <linux/spinlock.h>
+#include <linux/module.h>
+#include <linux/timer.h>
+#include <linux/mm.h>
+#include <linux/random.h>
+#include <linux/skbuff.h>
+#include <linux/rtnetlink.h>
+#include <linux/slab.h>
+#include <linux/rhashtable.h>
+
+#include <net/sock.h>
+#include <net/inet_frag.h>
+#include <net/inet_ecn.h>
+#include <net/ip.h>
+#include <net/ipv6.h>
+
+/* Use skb->cb to track consecutive/adjacent fragments coming at
+ * the end of the queue. Nodes in the rb-tree queue will
+ * contain "runs" of one or more adjacent fragments.
+ *
+ * Invariants:
+ * - next_frag is NULL at the tail of a "run";
+ * - the head of a "run" has the sum of all fragment lengths in frag_run_len.
+ */
+struct ipfrag_skb_cb {
+ union {
+ struct inet_skb_parm h4;
+ struct inet6_skb_parm h6;
+ };
+ struct sk_buff *next_frag;
+ int frag_run_len;
+};
+
+#define FRAG_CB(skb) ((struct ipfrag_skb_cb *)((skb)->cb))
+
+static void fragcb_clear(struct sk_buff *skb)
+{
+ RB_CLEAR_NODE(&skb->rbnode);
+ FRAG_CB(skb)->next_frag = NULL;
+ FRAG_CB(skb)->frag_run_len = skb->len;
+}
+
+/* Append skb to the last "run". */
+static void fragrun_append_to_last(struct inet_frag_queue *q,
+ struct sk_buff *skb)
+{
+ fragcb_clear(skb);
+
+ FRAG_CB(q->last_run_head)->frag_run_len += skb->len;
+ FRAG_CB(q->fragments_tail)->next_frag = skb;
+ q->fragments_tail = skb;
+}
+
+/* Create a new "run" with the skb. */
+static void fragrun_create(struct inet_frag_queue *q, struct sk_buff *skb)
+{
+ BUILD_BUG_ON(sizeof(struct ipfrag_skb_cb) > sizeof(skb->cb));
+ fragcb_clear(skb);
+
+ if (q->last_run_head)
+ rb_link_node(&skb->rbnode, &q->last_run_head->rbnode,
+ &q->last_run_head->rbnode.rb_right);
+ else
+ rb_link_node(&skb->rbnode, NULL, &q->rb_fragments.rb_node);
+ rb_insert_color(&skb->rbnode, &q->rb_fragments);
+
+ q->fragments_tail = skb;
+ q->last_run_head = skb;
+}
+
+/* Given the OR values of all fragments, apply RFC 3168 5.3 requirements
+ * Value : 0xff if frame should be dropped.
+ * 0 or INET_ECN_CE value, to be ORed in to final iph->tos field
+ */
+const u8 ip_frag_ecn_table[16] = {
+ /* at least one fragment had CE, and others ECT_0 or ECT_1 */
+ [IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0] = INET_ECN_CE,
+ [IPFRAG_ECN_CE | IPFRAG_ECN_ECT_1] = INET_ECN_CE,
+ [IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0 | IPFRAG_ECN_ECT_1] = INET_ECN_CE,
+
+ /* invalid combinations : drop frame */
+ [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE] = 0xff,
+ [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_ECT_0] = 0xff,
+ [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_ECT_1] = 0xff,
+ [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_ECT_0 | IPFRAG_ECN_ECT_1] = 0xff,
+ [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0] = 0xff,
+ [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE | IPFRAG_ECN_ECT_1] = 0xff,
+ [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0 | IPFRAG_ECN_ECT_1] = 0xff,
+};
+EXPORT_SYMBOL(ip_frag_ecn_table);
+
+int inet_frags_init(struct inet_frags *f)
+{
+ f->frags_cachep = kmem_cache_create(f->frags_cache_name, f->qsize, 0, 0,
+ NULL);
+ if (!f->frags_cachep)
+ return -ENOMEM;
+
+ refcount_set(&f->refcnt, 1);
+ init_completion(&f->completion);
+ return 0;
+}
+EXPORT_SYMBOL(inet_frags_init);
+
+void inet_frags_fini(struct inet_frags *f)
+{
+ if (refcount_dec_and_test(&f->refcnt))
+ complete(&f->completion);
+
+ wait_for_completion(&f->completion);
+
+ kmem_cache_destroy(f->frags_cachep);
+ f->frags_cachep = NULL;
+}
+EXPORT_SYMBOL(inet_frags_fini);
+
+/* called from rhashtable_free_and_destroy() at netns_frags dismantle */
+static void inet_frags_free_cb(void *ptr, void *arg)
+{
+ struct inet_frag_queue *fq = ptr;
+ int count;
+
+ count = del_timer_sync(&fq->timer) ? 1 : 0;
+
+ spin_lock_bh(&fq->lock);
+ if (!(fq->flags & INET_FRAG_COMPLETE)) {
+ fq->flags |= INET_FRAG_COMPLETE;
+ count++;
+ } else if (fq->flags & INET_FRAG_HASH_DEAD) {
+ count++;
+ }
+ spin_unlock_bh(&fq->lock);
+
+ if (refcount_sub_and_test(count, &fq->refcnt))
+ inet_frag_destroy(fq);
+}
+
+static LLIST_HEAD(fqdir_free_list);
+
+static void fqdir_free_fn(struct work_struct *work)
+{
+ struct llist_node *kill_list;
+ struct fqdir *fqdir, *tmp;
+ struct inet_frags *f;
+
+ /* Atomically snapshot the list of fqdirs to free */
+ kill_list = llist_del_all(&fqdir_free_list);
+
+ /* We need to make sure all ongoing call_rcu(..., inet_frag_destroy_rcu)
+ * have completed, since they need to dereference fqdir.
+ * Would it not be nice to have kfree_rcu_barrier() ? :)
+ */
+ rcu_barrier();
+
+ llist_for_each_entry_safe(fqdir, tmp, kill_list, free_list) {
+ f = fqdir->f;
+ if (refcount_dec_and_test(&f->refcnt))
+ complete(&f->completion);
+
+ kfree(fqdir);
+ }
+}
+
+static DECLARE_WORK(fqdir_free_work, fqdir_free_fn);
+
+static void fqdir_work_fn(struct work_struct *work)
+{
+ struct fqdir *fqdir = container_of(work, struct fqdir, destroy_work);
+
+ rhashtable_free_and_destroy(&fqdir->rhashtable, inet_frags_free_cb, NULL);
+
+ if (llist_add(&fqdir->free_list, &fqdir_free_list))
+ queue_work(system_wq, &fqdir_free_work);
+}
+
+int fqdir_init(struct fqdir **fqdirp, struct inet_frags *f, struct net *net)
+{
+ struct fqdir *fqdir = kzalloc(sizeof(*fqdir), GFP_KERNEL);
+ int res;
+
+ if (!fqdir)
+ return -ENOMEM;
+ fqdir->f = f;
+ fqdir->net = net;
+ res = rhashtable_init(&fqdir->rhashtable, &fqdir->f->rhash_params);
+ if (res < 0) {
+ kfree(fqdir);
+ return res;
+ }
+ refcount_inc(&f->refcnt);
+ *fqdirp = fqdir;
+ return 0;
+}
+EXPORT_SYMBOL(fqdir_init);
+
+static struct workqueue_struct *inet_frag_wq;
+
+static int __init inet_frag_wq_init(void)
+{
+ inet_frag_wq = create_workqueue("inet_frag_wq");
+ if (!inet_frag_wq)
+ panic("Could not create inet frag workq");
+ return 0;
+}
+
+pure_initcall(inet_frag_wq_init);
+
+void fqdir_exit(struct fqdir *fqdir)
+{
+ INIT_WORK(&fqdir->destroy_work, fqdir_work_fn);
+ queue_work(inet_frag_wq, &fqdir->destroy_work);
+}
+EXPORT_SYMBOL(fqdir_exit);
+
+void inet_frag_kill(struct inet_frag_queue *fq)
+{
+ if (del_timer(&fq->timer))
+ refcount_dec(&fq->refcnt);
+
+ if (!(fq->flags & INET_FRAG_COMPLETE)) {
+ struct fqdir *fqdir = fq->fqdir;
+
+ fq->flags |= INET_FRAG_COMPLETE;
+ rcu_read_lock();
+ /* The RCU read lock provides a memory barrier
+ * guaranteeing that if fqdir->dead is false then
+ * the hash table destruction will not start until
+ * after we unlock. Paired with fqdir_pre_exit().
+ */
+ if (!READ_ONCE(fqdir->dead)) {
+ rhashtable_remove_fast(&fqdir->rhashtable, &fq->node,
+ fqdir->f->rhash_params);
+ refcount_dec(&fq->refcnt);
+ } else {
+ fq->flags |= INET_FRAG_HASH_DEAD;
+ }
+ rcu_read_unlock();
+ }
+}
+EXPORT_SYMBOL(inet_frag_kill);
+
+static void inet_frag_destroy_rcu(struct rcu_head *head)
+{
+ struct inet_frag_queue *q = container_of(head, struct inet_frag_queue,
+ rcu);
+ struct inet_frags *f = q->fqdir->f;
+
+ if (f->destructor)
+ f->destructor(q);
+ kmem_cache_free(f->frags_cachep, q);
+}
+
+unsigned int inet_frag_rbtree_purge(struct rb_root *root)
+{
+ struct rb_node *p = rb_first(root);
+ unsigned int sum = 0;
+
+ while (p) {
+ struct sk_buff *skb = rb_entry(p, struct sk_buff, rbnode);
+
+ p = rb_next(p);
+ rb_erase(&skb->rbnode, root);
+ while (skb) {
+ struct sk_buff *next = FRAG_CB(skb)->next_frag;
+
+ sum += skb->truesize;
+ kfree_skb(skb);
+ skb = next;
+ }
+ }
+ return sum;
+}
+EXPORT_SYMBOL(inet_frag_rbtree_purge);
+
+void inet_frag_destroy(struct inet_frag_queue *q)
+{
+ struct fqdir *fqdir;
+ unsigned int sum, sum_truesize = 0;
+ struct inet_frags *f;
+
+ WARN_ON(!(q->flags & INET_FRAG_COMPLETE));
+ WARN_ON(del_timer(&q->timer) != 0);
+
+ /* Release all fragment data. */
+ fqdir = q->fqdir;
+ f = fqdir->f;
+ sum_truesize = inet_frag_rbtree_purge(&q->rb_fragments);
+ sum = sum_truesize + f->qsize;
+
+ call_rcu(&q->rcu, inet_frag_destroy_rcu);
+
+ sub_frag_mem_limit(fqdir, sum);
+}
+EXPORT_SYMBOL(inet_frag_destroy);
+
+static struct inet_frag_queue *inet_frag_alloc(struct fqdir *fqdir,
+ struct inet_frags *f,
+ void *arg)
+{
+ struct inet_frag_queue *q;
+
+ q = kmem_cache_zalloc(f->frags_cachep, GFP_ATOMIC);
+ if (!q)
+ return NULL;
+
+ q->fqdir = fqdir;
+ f->constructor(q, arg);
+ add_frag_mem_limit(fqdir, f->qsize);
+
+ timer_setup(&q->timer, f->frag_expire, 0);
+ spin_lock_init(&q->lock);
+ refcount_set(&q->refcnt, 3);
+
+ return q;
+}
+
+static struct inet_frag_queue *inet_frag_create(struct fqdir *fqdir,
+ void *arg,
+ struct inet_frag_queue **prev)
+{
+ struct inet_frags *f = fqdir->f;
+ struct inet_frag_queue *q;
+
+ q = inet_frag_alloc(fqdir, f, arg);
+ if (!q) {
+ *prev = ERR_PTR(-ENOMEM);
+ return NULL;
+ }
+ mod_timer(&q->timer, jiffies + fqdir->timeout);
+
+ *prev = rhashtable_lookup_get_insert_key(&fqdir->rhashtable, &q->key,
+ &q->node, f->rhash_params);
+ if (*prev) {
+ q->flags |= INET_FRAG_COMPLETE;
+ inet_frag_kill(q);
+ inet_frag_destroy(q);
+ return NULL;
+ }
+ return q;
+}
+
+/* TODO : call from rcu_read_lock() and no longer use refcount_inc_not_zero() */
+struct inet_frag_queue *inet_frag_find(struct fqdir *fqdir, void *key)
+{
+ /* This pairs with WRITE_ONCE() in fqdir_pre_exit(). */
+ long high_thresh = READ_ONCE(fqdir->high_thresh);
+ struct inet_frag_queue *fq = NULL, *prev;
+
+ if (!high_thresh || frag_mem_limit(fqdir) > high_thresh)
+ return NULL;
+
+ rcu_read_lock();
+
+ prev = rhashtable_lookup(&fqdir->rhashtable, key, fqdir->f->rhash_params);
+ if (!prev)
+ fq = inet_frag_create(fqdir, key, &prev);
+ if (!IS_ERR_OR_NULL(prev)) {
+ fq = prev;
+ if (!refcount_inc_not_zero(&fq->refcnt))
+ fq = NULL;
+ }
+ rcu_read_unlock();
+ return fq;
+}
+EXPORT_SYMBOL(inet_frag_find);
+
+int inet_frag_queue_insert(struct inet_frag_queue *q, struct sk_buff *skb,
+ int offset, int end)
+{
+ struct sk_buff *last = q->fragments_tail;
+
+ /* 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.
+ *
+ * Duplicates, however, should be ignored (i.e. skb dropped, but the
+ * queue/fragments kept for later reassembly).
+ */
+ if (!last)
+ fragrun_create(q, skb); /* First fragment. */
+ else if (last->ip_defrag_offset + last->len < end) {
+ /* This is the common case: skb goes to the end. */
+ /* Detect and discard overlaps. */
+ if (offset < last->ip_defrag_offset + last->len)
+ return IPFRAG_OVERLAP;
+ if (offset == last->ip_defrag_offset + last->len)
+ fragrun_append_to_last(q, skb);
+ else
+ fragrun_create(q, skb);
+ } else {
+ /* Binary search. Note that skb can become the first fragment,
+ * but not the last (covered above).
+ */
+ struct rb_node **rbn, *parent;
+
+ rbn = &q->rb_fragments.rb_node;
+ do {
+ struct sk_buff *curr;
+ int curr_run_end;
+
+ parent = *rbn;
+ curr = rb_to_skb(parent);
+ curr_run_end = curr->ip_defrag_offset +
+ FRAG_CB(curr)->frag_run_len;
+ if (end <= curr->ip_defrag_offset)
+ rbn = &parent->rb_left;
+ else if (offset >= curr_run_end)
+ rbn = &parent->rb_right;
+ else if (offset >= curr->ip_defrag_offset &&
+ end <= curr_run_end)
+ return IPFRAG_DUP;
+ else
+ return IPFRAG_OVERLAP;
+ } while (*rbn);
+ /* Here we have parent properly set, and rbn pointing to
+ * one of its NULL left/right children. Insert skb.
+ */
+ fragcb_clear(skb);
+ rb_link_node(&skb->rbnode, parent, rbn);
+ rb_insert_color(&skb->rbnode, &q->rb_fragments);
+ }
+
+ skb->ip_defrag_offset = offset;
+
+ return IPFRAG_OK;
+}
+EXPORT_SYMBOL(inet_frag_queue_insert);
+
+void *inet_frag_reasm_prepare(struct inet_frag_queue *q, struct sk_buff *skb,
+ struct sk_buff *parent)
+{
+ struct sk_buff *fp, *head = skb_rb_first(&q->rb_fragments);
+ struct sk_buff **nextp;
+ int delta;
+
+ if (head != skb) {
+ fp = skb_clone(skb, GFP_ATOMIC);
+ if (!fp)
+ return NULL;
+ FRAG_CB(fp)->next_frag = FRAG_CB(skb)->next_frag;
+ if (RB_EMPTY_NODE(&skb->rbnode))
+ FRAG_CB(parent)->next_frag = fp;
+ else
+ rb_replace_node(&skb->rbnode, &fp->rbnode,
+ &q->rb_fragments);
+ if (q->fragments_tail == skb)
+ q->fragments_tail = fp;
+ skb_morph(skb, head);
+ FRAG_CB(skb)->next_frag = FRAG_CB(head)->next_frag;
+ rb_replace_node(&head->rbnode, &skb->rbnode,
+ &q->rb_fragments);
+ consume_skb(head);
+ head = skb;
+ }
+ WARN_ON(head->ip_defrag_offset != 0);
+
+ delta = -head->truesize;
+
+ /* Head of list must not be cloned. */
+ if (skb_unclone(head, GFP_ATOMIC))
+ return NULL;
+
+ delta += head->truesize;
+ if (delta)
+ add_frag_mem_limit(q->fqdir, delta);
+
+ /* If the first fragment is fragmented itself, we split
+ * it to two chunks: the first with data and paged part
+ * and the second, holding only fragments.
+ */
+ if (skb_has_frag_list(head)) {
+ struct sk_buff *clone;
+ int i, plen = 0;
+
+ clone = alloc_skb(0, GFP_ATOMIC);
+ if (!clone)
+ return NULL;
+ skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
+ skb_frag_list_init(head);
+ for (i = 0; i < skb_shinfo(head)->nr_frags; i++)
+ plen += skb_frag_size(&skb_shinfo(head)->frags[i]);
+ clone->data_len = head->data_len - plen;
+ clone->len = clone->data_len;
+ head->truesize += clone->truesize;
+ clone->csum = 0;
+ clone->ip_summed = head->ip_summed;
+ add_frag_mem_limit(q->fqdir, clone->truesize);
+ skb_shinfo(head)->frag_list = clone;
+ nextp = &clone->next;
+ } else {
+ nextp = &skb_shinfo(head)->frag_list;
+ }
+
+ return nextp;
+}
+EXPORT_SYMBOL(inet_frag_reasm_prepare);
+
+void inet_frag_reasm_finish(struct inet_frag_queue *q, struct sk_buff *head,
+ void *reasm_data, bool try_coalesce)
+{
+ struct sk_buff **nextp = reasm_data;
+ struct rb_node *rbn;
+ struct sk_buff *fp;
+ int sum_truesize;
+
+ skb_push(head, head->data - skb_network_header(head));
+
+ /* Traverse the tree in order, to build frag_list. */
+ fp = FRAG_CB(head)->next_frag;
+ rbn = rb_next(&head->rbnode);
+ rb_erase(&head->rbnode, &q->rb_fragments);
+
+ sum_truesize = head->truesize;
+ while (rbn || fp) {
+ /* fp points to the next sk_buff in the current run;
+ * rbn points to the next run.
+ */
+ /* Go through the current run. */
+ while (fp) {
+ struct sk_buff *next_frag = FRAG_CB(fp)->next_frag;
+ bool stolen;
+ int delta;
+
+ sum_truesize += fp->truesize;
+ if (head->ip_summed != fp->ip_summed)
+ head->ip_summed = CHECKSUM_NONE;
+ else if (head->ip_summed == CHECKSUM_COMPLETE)
+ head->csum = csum_add(head->csum, fp->csum);
+
+ if (try_coalesce && skb_try_coalesce(head, fp, &stolen,
+ &delta)) {
+ kfree_skb_partial(fp, stolen);
+ } else {
+ fp->prev = NULL;
+ memset(&fp->rbnode, 0, sizeof(fp->rbnode));
+ fp->sk = NULL;
+
+ head->data_len += fp->len;
+ head->len += fp->len;
+ head->truesize += fp->truesize;
+
+ *nextp = fp;
+ nextp = &fp->next;
+ }
+
+ fp = next_frag;
+ }
+ /* Move to the next run. */
+ if (rbn) {
+ struct rb_node *rbnext = rb_next(rbn);
+
+ fp = rb_to_skb(rbn);
+ rb_erase(rbn, &q->rb_fragments);
+ rbn = rbnext;
+ }
+ }
+ sub_frag_mem_limit(q->fqdir, sum_truesize);
+
+ *nextp = NULL;
+ skb_mark_not_on_list(head);
+ head->prev = NULL;
+ head->tstamp = q->stamp;
+ head->mono_delivery_time = q->mono_delivery_time;
+}
+EXPORT_SYMBOL(inet_frag_reasm_finish);
+
+struct sk_buff *inet_frag_pull_head(struct inet_frag_queue *q)
+{
+ struct sk_buff *head, *skb;
+
+ head = skb_rb_first(&q->rb_fragments);
+ if (!head)
+ return NULL;
+ skb = FRAG_CB(head)->next_frag;
+ if (skb)
+ rb_replace_node(&head->rbnode, &skb->rbnode,
+ &q->rb_fragments);
+ else
+ rb_erase(&head->rbnode, &q->rb_fragments);
+ memset(&head->rbnode, 0, sizeof(head->rbnode));
+ barrier();
+
+ if (head == q->fragments_tail)
+ q->fragments_tail = NULL;
+
+ sub_frag_mem_limit(q->fqdir, head->truesize);
+
+ return head;
+}
+EXPORT_SYMBOL(inet_frag_pull_head);