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authorLinus Torvalds <torvalds@linux-foundation.org>2014-12-11 14:27:06 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2014-12-11 14:27:06 -0800
commit70e71ca0af244f48a5dcf56dc435243792e3a495 (patch)
treef7d9c4c4d9a857a00043e9bf6aa2d6f533a34778 /kernel/bpf/hashtab.c
parentMerge tag 'sound-3.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound (diff)
parentFix race condition between vxlan_sock_add and vxlan_sock_release (diff)
downloadlinux-dev-70e71ca0af244f48a5dcf56dc435243792e3a495.tar.xz
linux-dev-70e71ca0af244f48a5dcf56dc435243792e3a495.zip
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next
Pull networking updates from David Miller: 1) New offloading infrastructure and example 'rocker' driver for offloading of switching and routing to hardware. This work was done by a large group of dedicated individuals, not limited to: Scott Feldman, Jiri Pirko, Thomas Graf, John Fastabend, Jamal Hadi Salim, Andy Gospodarek, Florian Fainelli, Roopa Prabhu 2) Start making the networking operate on IOV iterators instead of modifying iov objects in-situ during transfers. Thanks to Al Viro and Herbert Xu. 3) A set of new netlink interfaces for the TIPC stack, from Richard Alpe. 4) Remove unnecessary looping during ipv6 routing lookups, from Martin KaFai Lau. 5) Add PAUSE frame generation support to gianfar driver, from Matei Pavaluca. 6) Allow for larger reordering levels in TCP, which are easily achievable in the real world right now, from Eric Dumazet. 7) Add a variable of napi_schedule that doesn't need to disable cpu interrupts, from Eric Dumazet. 8) Use a doubly linked list to optimize neigh_parms_release(), from Nicolas Dichtel. 9) Various enhancements to the kernel BPF verifier, and allow eBPF programs to actually be attached to sockets. From Alexei Starovoitov. 10) Support TSO/LSO in sunvnet driver, from David L Stevens. 11) Allow controlling ECN usage via routing metrics, from Florian Westphal. 12) Remote checksum offload, from Tom Herbert. 13) Add split-header receive, BQL, and xmit_more support to amd-xgbe driver, from Thomas Lendacky. 14) Add MPLS support to openvswitch, from Simon Horman. 15) Support wildcard tunnel endpoints in ipv6 tunnels, from Steffen Klassert. 16) Do gro flushes on a per-device basis using a timer, from Eric Dumazet. This tries to resolve the conflicting goals between the desired handling of bulk vs. RPC-like traffic. 17) Allow userspace to ask for the CPU upon what a packet was received/steered, via SO_INCOMING_CPU. From Eric Dumazet. 18) Limit GSO packets to half the current congestion window, from Eric Dumazet. 19) Add a generic helper so that all drivers set their RSS keys in a consistent way, from Eric Dumazet. 20) Add xmit_more support to enic driver, from Govindarajulu Varadarajan. 21) Add VLAN packet scheduler action, from Jiri Pirko. 22) Support configurable RSS hash functions via ethtool, from Eyal Perry. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1820 commits) Fix race condition between vxlan_sock_add and vxlan_sock_release net/macb: fix compilation warning for print_hex_dump() called with skb->mac_header net/mlx4: Add support for A0 steering net/mlx4: Refactor QUERY_PORT net/mlx4_core: Add explicit error message when rule doesn't meet configuration net/mlx4: Add A0 hybrid steering net/mlx4: Add mlx4_bitmap zone allocator net/mlx4: Add a check if there are too many reserved QPs net/mlx4: Change QP allocation scheme net/mlx4_core: Use tasklet for user-space CQ completion events net/mlx4_core: Mask out host side virtualization features for guests net/mlx4_en: Set csum level for encapsulated packets be2net: Export tunnel offloads only when a VxLAN tunnel is created gianfar: Fix dma check map error when DMA_API_DEBUG is enabled cxgb4/csiostor: Don't use MASTER_MUST for fw_hello call net: fec: only enable mdio interrupt before phy device link up net: fec: clear all interrupt events to support i.MX6SX net: fec: reset fep link status in suspend function net: sock: fix access via invalid file descriptor net: introduce helper macro for_each_cmsghdr ...
Diffstat (limited to 'kernel/bpf/hashtab.c')
-rw-r--r--kernel/bpf/hashtab.c367
1 files changed, 367 insertions, 0 deletions
diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c
new file mode 100644
index 000000000000..b3ba43674310
--- /dev/null
+++ b/kernel/bpf/hashtab.c
@@ -0,0 +1,367 @@
+/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ */
+#include <linux/bpf.h>
+#include <linux/jhash.h>
+#include <linux/filter.h>
+#include <linux/vmalloc.h>
+
+struct bpf_htab {
+ struct bpf_map map;
+ struct hlist_head *buckets;
+ spinlock_t lock;
+ u32 count; /* number of elements in this hashtable */
+ u32 n_buckets; /* number of hash buckets */
+ u32 elem_size; /* size of each element in bytes */
+};
+
+/* each htab element is struct htab_elem + key + value */
+struct htab_elem {
+ struct hlist_node hash_node;
+ struct rcu_head rcu;
+ u32 hash;
+ char key[0] __aligned(8);
+};
+
+/* Called from syscall */
+static struct bpf_map *htab_map_alloc(union bpf_attr *attr)
+{
+ struct bpf_htab *htab;
+ int err, i;
+
+ htab = kzalloc(sizeof(*htab), GFP_USER);
+ if (!htab)
+ return ERR_PTR(-ENOMEM);
+
+ /* mandatory map attributes */
+ htab->map.key_size = attr->key_size;
+ htab->map.value_size = attr->value_size;
+ htab->map.max_entries = attr->max_entries;
+
+ /* check sanity of attributes.
+ * value_size == 0 may be allowed in the future to use map as a set
+ */
+ err = -EINVAL;
+ if (htab->map.max_entries == 0 || htab->map.key_size == 0 ||
+ htab->map.value_size == 0)
+ goto free_htab;
+
+ /* hash table size must be power of 2 */
+ htab->n_buckets = roundup_pow_of_two(htab->map.max_entries);
+
+ err = -E2BIG;
+ if (htab->map.key_size > MAX_BPF_STACK)
+ /* eBPF programs initialize keys on stack, so they cannot be
+ * larger than max stack size
+ */
+ goto free_htab;
+
+ err = -ENOMEM;
+ /* prevent zero size kmalloc and check for u32 overflow */
+ if (htab->n_buckets == 0 ||
+ htab->n_buckets > U32_MAX / sizeof(struct hlist_head))
+ goto free_htab;
+
+ htab->buckets = kmalloc_array(htab->n_buckets, sizeof(struct hlist_head),
+ GFP_USER | __GFP_NOWARN);
+
+ if (!htab->buckets) {
+ htab->buckets = vmalloc(htab->n_buckets * sizeof(struct hlist_head));
+ if (!htab->buckets)
+ goto free_htab;
+ }
+
+ for (i = 0; i < htab->n_buckets; i++)
+ INIT_HLIST_HEAD(&htab->buckets[i]);
+
+ spin_lock_init(&htab->lock);
+ htab->count = 0;
+
+ htab->elem_size = sizeof(struct htab_elem) +
+ round_up(htab->map.key_size, 8) +
+ htab->map.value_size;
+ return &htab->map;
+
+free_htab:
+ kfree(htab);
+ return ERR_PTR(err);
+}
+
+static inline u32 htab_map_hash(const void *key, u32 key_len)
+{
+ return jhash(key, key_len, 0);
+}
+
+static inline struct hlist_head *select_bucket(struct bpf_htab *htab, u32 hash)
+{
+ return &htab->buckets[hash & (htab->n_buckets - 1)];
+}
+
+static struct htab_elem *lookup_elem_raw(struct hlist_head *head, u32 hash,
+ void *key, u32 key_size)
+{
+ struct htab_elem *l;
+
+ hlist_for_each_entry_rcu(l, head, hash_node)
+ if (l->hash == hash && !memcmp(&l->key, key, key_size))
+ return l;
+
+ return NULL;
+}
+
+/* Called from syscall or from eBPF program */
+static void *htab_map_lookup_elem(struct bpf_map *map, void *key)
+{
+ struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+ struct hlist_head *head;
+ struct htab_elem *l;
+ u32 hash, key_size;
+
+ /* Must be called with rcu_read_lock. */
+ WARN_ON_ONCE(!rcu_read_lock_held());
+
+ key_size = map->key_size;
+
+ hash = htab_map_hash(key, key_size);
+
+ head = select_bucket(htab, hash);
+
+ l = lookup_elem_raw(head, hash, key, key_size);
+
+ if (l)
+ return l->key + round_up(map->key_size, 8);
+
+ return NULL;
+}
+
+/* Called from syscall */
+static int htab_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
+{
+ struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+ struct hlist_head *head;
+ struct htab_elem *l, *next_l;
+ u32 hash, key_size;
+ int i;
+
+ WARN_ON_ONCE(!rcu_read_lock_held());
+
+ key_size = map->key_size;
+
+ hash = htab_map_hash(key, key_size);
+
+ head = select_bucket(htab, hash);
+
+ /* lookup the key */
+ l = lookup_elem_raw(head, hash, key, key_size);
+
+ if (!l) {
+ i = 0;
+ goto find_first_elem;
+ }
+
+ /* key was found, get next key in the same bucket */
+ next_l = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu(&l->hash_node)),
+ struct htab_elem, hash_node);
+
+ if (next_l) {
+ /* if next elem in this hash list is non-zero, just return it */
+ memcpy(next_key, next_l->key, key_size);
+ return 0;
+ }
+
+ /* no more elements in this hash list, go to the next bucket */
+ i = hash & (htab->n_buckets - 1);
+ i++;
+
+find_first_elem:
+ /* iterate over buckets */
+ for (; i < htab->n_buckets; i++) {
+ head = select_bucket(htab, i);
+
+ /* pick first element in the bucket */
+ next_l = hlist_entry_safe(rcu_dereference_raw(hlist_first_rcu(head)),
+ struct htab_elem, hash_node);
+ if (next_l) {
+ /* if it's not empty, just return it */
+ memcpy(next_key, next_l->key, key_size);
+ return 0;
+ }
+ }
+
+ /* itereated over all buckets and all elements */
+ return -ENOENT;
+}
+
+/* Called from syscall or from eBPF program */
+static int htab_map_update_elem(struct bpf_map *map, void *key, void *value,
+ u64 map_flags)
+{
+ struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+ struct htab_elem *l_new, *l_old;
+ struct hlist_head *head;
+ unsigned long flags;
+ u32 key_size;
+ int ret;
+
+ if (map_flags > BPF_EXIST)
+ /* unknown flags */
+ return -EINVAL;
+
+ WARN_ON_ONCE(!rcu_read_lock_held());
+
+ /* allocate new element outside of lock */
+ l_new = kmalloc(htab->elem_size, GFP_ATOMIC);
+ if (!l_new)
+ return -ENOMEM;
+
+ key_size = map->key_size;
+
+ memcpy(l_new->key, key, key_size);
+ memcpy(l_new->key + round_up(key_size, 8), value, map->value_size);
+
+ l_new->hash = htab_map_hash(l_new->key, key_size);
+
+ /* bpf_map_update_elem() can be called in_irq() */
+ spin_lock_irqsave(&htab->lock, flags);
+
+ head = select_bucket(htab, l_new->hash);
+
+ l_old = lookup_elem_raw(head, l_new->hash, key, key_size);
+
+ if (!l_old && unlikely(htab->count >= map->max_entries)) {
+ /* if elem with this 'key' doesn't exist and we've reached
+ * max_entries limit, fail insertion of new elem
+ */
+ ret = -E2BIG;
+ goto err;
+ }
+
+ if (l_old && map_flags == BPF_NOEXIST) {
+ /* elem already exists */
+ ret = -EEXIST;
+ goto err;
+ }
+
+ if (!l_old && map_flags == BPF_EXIST) {
+ /* elem doesn't exist, cannot update it */
+ ret = -ENOENT;
+ goto err;
+ }
+
+ /* add new element to the head of the list, so that concurrent
+ * search will find it before old elem
+ */
+ hlist_add_head_rcu(&l_new->hash_node, head);
+ if (l_old) {
+ hlist_del_rcu(&l_old->hash_node);
+ kfree_rcu(l_old, rcu);
+ } else {
+ htab->count++;
+ }
+ spin_unlock_irqrestore(&htab->lock, flags);
+
+ return 0;
+err:
+ spin_unlock_irqrestore(&htab->lock, flags);
+ kfree(l_new);
+ return ret;
+}
+
+/* Called from syscall or from eBPF program */
+static int htab_map_delete_elem(struct bpf_map *map, void *key)
+{
+ struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+ struct hlist_head *head;
+ struct htab_elem *l;
+ unsigned long flags;
+ u32 hash, key_size;
+ int ret = -ENOENT;
+
+ WARN_ON_ONCE(!rcu_read_lock_held());
+
+ key_size = map->key_size;
+
+ hash = htab_map_hash(key, key_size);
+
+ spin_lock_irqsave(&htab->lock, flags);
+
+ head = select_bucket(htab, hash);
+
+ l = lookup_elem_raw(head, hash, key, key_size);
+
+ if (l) {
+ hlist_del_rcu(&l->hash_node);
+ htab->count--;
+ kfree_rcu(l, rcu);
+ ret = 0;
+ }
+
+ spin_unlock_irqrestore(&htab->lock, flags);
+ return ret;
+}
+
+static void delete_all_elements(struct bpf_htab *htab)
+{
+ int i;
+
+ for (i = 0; i < htab->n_buckets; i++) {
+ struct hlist_head *head = select_bucket(htab, i);
+ struct hlist_node *n;
+ struct htab_elem *l;
+
+ hlist_for_each_entry_safe(l, n, head, hash_node) {
+ hlist_del_rcu(&l->hash_node);
+ htab->count--;
+ kfree(l);
+ }
+ }
+}
+
+/* Called when map->refcnt goes to zero, either from workqueue or from syscall */
+static void htab_map_free(struct bpf_map *map)
+{
+ struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+
+ /* at this point bpf_prog->aux->refcnt == 0 and this map->refcnt == 0,
+ * so the programs (can be more than one that used this map) were
+ * disconnected from events. Wait for outstanding critical sections in
+ * these programs to complete
+ */
+ synchronize_rcu();
+
+ /* some of kfree_rcu() callbacks for elements of this map may not have
+ * executed. It's ok. Proceed to free residual elements and map itself
+ */
+ delete_all_elements(htab);
+ kvfree(htab->buckets);
+ kfree(htab);
+}
+
+static struct bpf_map_ops htab_ops = {
+ .map_alloc = htab_map_alloc,
+ .map_free = htab_map_free,
+ .map_get_next_key = htab_map_get_next_key,
+ .map_lookup_elem = htab_map_lookup_elem,
+ .map_update_elem = htab_map_update_elem,
+ .map_delete_elem = htab_map_delete_elem,
+};
+
+static struct bpf_map_type_list tl = {
+ .ops = &htab_ops,
+ .type = BPF_MAP_TYPE_HASH,
+};
+
+static int __init register_htab_map(void)
+{
+ bpf_register_map_type(&tl);
+ return 0;
+}
+late_initcall(register_htab_map);