@@ -281,7 +281,7 @@ static int pptp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
nf_reset(skb);
skb->ip_summed = CHECKSUM_NONE;
- ip_select_ident(skb, &rt->dst, NULL);
+ ip_select_ident(skb, NULL);
ip_send_check(iph);
ip_local_out(skb);
@@ -41,14 +41,13 @@ struct inet_peer {
struct rcu_head gc_rcu;
};
/*
- * Once inet_peer is queued for deletion (refcnt == -1), following fields
- * are not available: rid, ip_id_count
+ * Once inet_peer is queued for deletion (refcnt == -1), following field
+ * is not available: rid
* We can share memory with rcu_head to help keep inet_peer small.
*/
union {
struct {
atomic_t rid; /* Frag reception counter */
- atomic_t ip_id_count; /* IP ID for the next packet */
};
struct rcu_head rcu;
struct inet_peer *gc_next;
@@ -166,7 +165,7 @@ void inetpeer_invalidate_tree(struct inet_peer_base *);
void inetpeer_invalidate_family(int family);
/*
- * temporary check to make sure we dont access rid, ip_id_count, tcp_ts,
+ * temporary check to make sure we dont access rid, tcp_ts,
* tcp_ts_stamp if no refcount is taken on inet_peer
*/
static inline void inet_peer_refcheck(const struct inet_peer *p)
@@ -174,13 +173,4 @@ static inline void inet_peer_refcheck(const struct inet_peer *p)
WARN_ON_ONCE(atomic_read(&p->refcnt) <= 0);
}
-
-/* can be called with or without local BH being disabled */
-static inline int inet_getid(struct inet_peer *p, int more)
-{
- more++;
- inet_peer_refcheck(p);
- return atomic_add_return(more, &p->ip_id_count) - more;
-}
-
#endif /* _NET_INETPEER_H */
@@ -269,9 +269,19 @@ int ip_dont_fragment(struct sock *sk, struct dst_entry *dst)
!(dst_metric_locked(dst, RTAX_MTU)));
}
-void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more);
+#define IP_IDENTS_SZ 2048u
+extern atomic_t *ip_idents;
-static inline void ip_select_ident(struct sk_buff *skb, struct dst_entry *dst, struct sock *sk)
+static inline u32 ip_idents_reserve(u32 hash, int segs)
+{
+ atomic_t *id_ptr = ip_idents + hash % IP_IDENTS_SZ;
+
+ return atomic_add_return(segs, id_ptr) - segs;
+}
+
+void __ip_select_ident(struct iphdr *iph, int segs);
+
+static inline void ip_select_ident_segs(struct sk_buff *skb, struct sock *sk, int segs)
{
struct iphdr *iph = ip_hdr(skb);
@@ -281,24 +291,20 @@ static inline void ip_select_ident(struct sk_buff *skb, struct dst_entry *dst, s
* does not change, they drop every other packet in
* a TCP stream using header compression.
*/
- iph->id = (sk && inet_sk(sk)->inet_daddr) ?
- htons(inet_sk(sk)->inet_id++) : 0;
- } else
- __ip_select_ident(iph, dst, 0);
-}
-
-static inline void ip_select_ident_more(struct sk_buff *skb, struct dst_entry *dst, struct sock *sk, int more)
-{
- struct iphdr *iph = ip_hdr(skb);
-
- if ((iph->frag_off & htons(IP_DF)) && !skb->local_df) {
if (sk && inet_sk(sk)->inet_daddr) {
iph->id = htons(inet_sk(sk)->inet_id);
- inet_sk(sk)->inet_id += 1 + more;
- } else
+ inet_sk(sk)->inet_id += segs;
+ } else {
iph->id = 0;
- } else
- __ip_select_ident(iph, dst, more);
+ }
+ } else {
+ __ip_select_ident(iph, segs);
+ }
+}
+
+static inline void ip_select_ident(struct sk_buff *skb, struct sock *sk)
+{
+ ip_select_ident_segs(skb, sk, 1);
}
/*
@@ -660,8 +660,6 @@ static inline int ipv6_addr_diff(const struct in6_addr *a1, const struct in6_add
return __ipv6_addr_diff(a1, a2, sizeof(struct in6_addr));
}
-void ipv6_select_ident(struct frag_hdr *fhdr, struct rt6_info *rt);
-
int ip6_dst_hoplimit(struct dst_entry *dst);
/*
@@ -3,8 +3,6 @@
#include <linux/types.h>
-__u32 secure_ip_id(__be32 daddr);
-__u32 secure_ipv6_id(const __be32 daddr[4]);
u32 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport);
u32 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr,
__be16 dport);
@@ -85,31 +85,6 @@ EXPORT_SYMBOL(secure_ipv6_port_ephemeral);
#endif
#ifdef CONFIG_INET
-__u32 secure_ip_id(__be32 daddr)
-{
- u32 hash[MD5_DIGEST_WORDS];
-
- net_secret_init();
- hash[0] = (__force __u32) daddr;
- hash[1] = net_secret[13];
- hash[2] = net_secret[14];
- hash[3] = net_secret[15];
-
- md5_transform(hash, net_secret);
-
- return hash[0];
-}
-
-__u32 secure_ipv6_id(const __be32 daddr[4])
-{
- __u32 hash[4];
-
- net_secret_init();
- memcpy(hash, daddr, 16);
- md5_transform(hash, net_secret);
-
- return hash[0];
-}
__u32 secure_tcp_sequence_number(__be32 saddr, __be32 daddr,
__be16 sport, __be16 dport)
@@ -369,7 +369,7 @@ static struct sk_buff *igmpv3_newpack(struct net_device *dev, int size)
pip->saddr = fl4.saddr;
pip->protocol = IPPROTO_IGMP;
pip->tot_len = 0; /* filled in later */
- ip_select_ident(skb, &rt->dst, NULL);
+ ip_select_ident(skb, NULL);
((u8 *)&pip[1])[0] = IPOPT_RA;
((u8 *)&pip[1])[1] = 4;
((u8 *)&pip[1])[2] = 0;
@@ -714,7 +714,7 @@ static int igmp_send_report(struct in_device *in_dev, struct ip_mc_list *pmc,
iph->daddr = dst;
iph->saddr = fl4.saddr;
iph->protocol = IPPROTO_IGMP;
- ip_select_ident(skb, &rt->dst, NULL);
+ ip_select_ident(skb, NULL);
((u8 *)&iph[1])[0] = IPOPT_RA;
((u8 *)&iph[1])[1] = 4;
((u8 *)&iph[1])[2] = 0;
@@ -26,20 +26,7 @@
* Theory of operations.
* We keep one entry for each peer IP address. The nodes contains long-living
* information about the peer which doesn't depend on routes.
- * At this moment this information consists only of ID field for the next
- * outgoing IP packet. This field is incremented with each packet as encoded
- * in inet_getid() function (include/net/inetpeer.h).
- * At the moment of writing this notes identifier of IP packets is generated
- * to be unpredictable using this code only for packets subjected
- * (actually or potentially) to defragmentation. I.e. DF packets less than
- * PMTU in size when local fragmentation is disabled use a constant ID and do
- * not use this code (see ip_select_ident() in include/net/ip.h).
*
- * Route cache entries hold references to our nodes.
- * New cache entries get references via lookup by destination IP address in
- * the avl tree. The reference is grabbed only when it's needed i.e. only
- * when we try to output IP packet which needs an unpredictable ID (see
- * __ip_select_ident() in net/ipv4/route.c).
* Nodes are removed only when reference counter goes to 0.
* When it's happened the node may be removed when a sufficient amount of
* time has been passed since its last use. The less-recently-used entry can
@@ -62,7 +49,6 @@
* refcnt: atomically against modifications on other CPU;
* usually under some other lock to prevent node disappearing
* daddr: unchangeable
- * ip_id_count: atomic value (no lock needed)
*/
static struct kmem_cache *peer_cachep __read_mostly;
@@ -504,10 +490,6 @@ relookup:
p->daddr = *daddr;
atomic_set(&p->refcnt, 1);
atomic_set(&p->rid, 0);
- atomic_set(&p->ip_id_count,
- (daddr->family == AF_INET) ?
- secure_ip_id(daddr->addr.a4) :
- secure_ipv6_id(daddr->addr.a6));
p->metrics[RTAX_LOCK-1] = INETPEER_METRICS_NEW;
p->rate_tokens = 0;
/* 60*HZ is arbitrary, but chosen enough high so that the first
@@ -148,7 +148,7 @@ int ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk,
iph->daddr = (opt && opt->opt.srr ? opt->opt.faddr : daddr);
iph->saddr = saddr;
iph->protocol = sk->sk_protocol;
- ip_select_ident(skb, &rt->dst, sk);
+ ip_select_ident(skb, sk);
if (opt && opt->opt.optlen) {
iph->ihl += opt->opt.optlen>>2;
@@ -386,8 +386,7 @@ packet_routed:
ip_options_build(skb, &inet_opt->opt, inet->inet_daddr, rt, 0);
}
- ip_select_ident_more(skb, &rt->dst, sk,
- (skb_shinfo(skb)->gso_segs ?: 1) - 1);
+ ip_select_ident_segs(skb, sk, skb_shinfo(skb)->gso_segs ?: 1);
skb->priority = sk->sk_priority;
skb->mark = sk->sk_mark;
@@ -1339,7 +1338,7 @@ struct sk_buff *__ip_make_skb(struct sock *sk,
iph->ttl = ttl;
iph->protocol = sk->sk_protocol;
ip_copy_addrs(iph, fl4);
- ip_select_ident(skb, &rt->dst, sk);
+ ip_select_ident(skb, sk);
if (opt) {
iph->ihl += opt->optlen>>2;
@@ -74,7 +74,7 @@ int iptunnel_xmit(struct rtable *rt, struct sk_buff *skb,
iph->daddr = dst;
iph->saddr = src;
iph->ttl = ttl;
- __ip_select_ident(iph, &rt->dst, (skb_shinfo(skb)->gso_segs ?: 1) - 1);
+ __ip_select_ident(iph, skb_shinfo(skb)->gso_segs ?: 1);
err = ip_local_out(skb);
if (unlikely(net_xmit_eval(err)))
@@ -1661,7 +1661,7 @@ static void ip_encap(struct sk_buff *skb, __be32 saddr, __be32 daddr)
iph->protocol = IPPROTO_IPIP;
iph->ihl = 5;
iph->tot_len = htons(skb->len);
- ip_select_ident(skb, skb_dst(skb), NULL);
+ ip_select_ident(skb, NULL);
ip_send_check(iph);
memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
@@ -389,7 +389,7 @@ static int raw_send_hdrinc(struct sock *sk, struct flowi4 *fl4,
iph->check = 0;
iph->tot_len = htons(length);
if (!iph->id)
- ip_select_ident(skb, &rt->dst, NULL);
+ ip_select_ident(skb, NULL);
iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl);
}
@@ -89,6 +89,7 @@
#include <linux/rcupdate.h>
#include <linux/times.h>
#include <linux/slab.h>
+#include <linux/jhash.h>
#include <net/dst.h>
#include <net/net_namespace.h>
#include <net/protocol.h>
@@ -465,39 +466,19 @@ static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
return neigh_create(&arp_tbl, pkey, dev);
}
-/*
- * Peer allocation may fail only in serious out-of-memory conditions. However
- * we still can generate some output.
- * Random ID selection looks a bit dangerous because we have no chances to
- * select ID being unique in a reasonable period of time.
- * But broken packet identifier may be better than no packet at all.
- */
-static void ip_select_fb_ident(struct iphdr *iph)
-{
- static DEFINE_SPINLOCK(ip_fb_id_lock);
- static u32 ip_fallback_id;
- u32 salt;
+atomic_t *ip_idents __read_mostly;
+EXPORT_SYMBOL(ip_idents);
- spin_lock_bh(&ip_fb_id_lock);
- salt = secure_ip_id((__force __be32)ip_fallback_id ^ iph->daddr);
- iph->id = htons(salt & 0xFFFF);
- ip_fallback_id = salt;
- spin_unlock_bh(&ip_fb_id_lock);
-}
-
-void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more)
+void __ip_select_ident(struct iphdr *iph, int segs)
{
- struct net *net = dev_net(dst->dev);
- struct inet_peer *peer;
+ static u32 ip_idents_hashrnd __read_mostly;
+ u32 hash, id;
- peer = inet_getpeer_v4(net->ipv4.peers, iph->daddr, 1);
- if (peer) {
- iph->id = htons(inet_getid(peer, more));
- inet_putpeer(peer);
- return;
- }
+ net_get_random_once(&ip_idents_hashrnd, sizeof(ip_idents_hashrnd));
- ip_select_fb_ident(iph);
+ hash = jhash_1word((__force u32)iph->daddr, ip_idents_hashrnd);
+ id = ip_idents_reserve(hash, segs);
+ iph->id = htons(id);
}
EXPORT_SYMBOL(__ip_select_ident);
@@ -2716,6 +2697,12 @@ int __init ip_rt_init(void)
{
int rc = 0;
+ ip_idents = kmalloc(IP_IDENTS_SZ * sizeof(*ip_idents), GFP_KERNEL);
+ if (!ip_idents)
+ panic("IP: failed to allocate ip_idents\n");
+
+ prandom_bytes(ip_idents, IP_IDENTS_SZ * sizeof(*ip_idents));
+
#ifdef CONFIG_IP_ROUTE_CLASSID
ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
if (!ip_rt_acct)
@@ -117,12 +117,12 @@ static int xfrm4_mode_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
top_iph->frag_off = (flags & XFRM_STATE_NOPMTUDISC) ?
0 : (XFRM_MODE_SKB_CB(skb)->frag_off & htons(IP_DF));
- ip_select_ident(skb, dst->child, NULL);
top_iph->ttl = ip4_dst_hoplimit(dst->child);
top_iph->saddr = x->props.saddr.a4;
top_iph->daddr = x->id.daddr.a4;
+ ip_select_ident(skb, NULL);
return 0;
}
@@ -516,6 +516,18 @@ static void ip6_copy_metadata(struct sk_buff *to, struct sk_buff *from)
skb_copy_secmark(to, from);
}
+static void ipv6_select_ident(struct frag_hdr *fhdr, struct rt6_info *rt)
+{
+ static u32 ip6_idents_hashrnd __read_mostly;
+ u32 hash, id;
+
+ net_get_random_once(&ip6_idents_hashrnd, sizeof(ip6_idents_hashrnd));
+
+ hash = __ipv6_addr_jhash(&rt->rt6i_dst.addr, ip6_idents_hashrnd);
+ id = ip_idents_reserve(hash, 1);
+ fhdr->identification = htonl(id);
+}
+
int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
{
struct sk_buff *frag;
@@ -7,29 +7,6 @@
#include <net/ip6_fib.h>
#include <net/addrconf.h>
-void ipv6_select_ident(struct frag_hdr *fhdr, struct rt6_info *rt)
-{
- static atomic_t ipv6_fragmentation_id;
- int ident;
-
-#if IS_ENABLED(CONFIG_IPV6)
- if (rt && !(rt->dst.flags & DST_NOPEER)) {
- struct inet_peer *peer;
- struct net *net;
-
- net = dev_net(rt->dst.dev);
- peer = inet_getpeer_v6(net->ipv6.peers, &rt->rt6i_dst.addr, 1);
- if (peer) {
- fhdr->identification = htonl(inet_getid(peer, 0));
- inet_putpeer(peer);
- return;
- }
- }
-#endif
- ident = atomic_inc_return(&ipv6_fragmentation_id);
- fhdr->identification = htonl(ident);
-}
-EXPORT_SYMBOL(ipv6_select_ident);
int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr)
{
@@ -883,7 +883,7 @@ ip_vs_tunnel_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
iph->daddr = cp->daddr.ip;
iph->saddr = saddr;
iph->ttl = old_iph->ttl;
- ip_select_ident(skb, &rt->dst, NULL);
+ ip_select_ident(skb, NULL);
/* Another hack: avoid icmp_send in ip_fragment */
skb->local_df = 1;
This is a note to let you know that I have just added a patch titled inetpeer: get rid of ip_id_count to the linux-3.13.y-queue branch of the 3.13.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue This patch is scheduled to be released in version 3.13.11.7. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.13.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ------ From a7d543baa9bd993ef91ad71e20fa532f34a83ae2 Mon Sep 17 00:00:00 2001 From: Eric Dumazet <edumazet@google.com> Date: Mon, 2 Jun 2014 05:26:03 -0700 Subject: inetpeer: get rid of ip_id_count [ Upstream commit 73f156a6e8c1074ac6327e0abd1169e95eb66463 ] Ideally, we would need to generate IP ID using a per destination IP generator. linux kernels used inet_peer cache for this purpose, but this had a huge cost on servers disabling MTU discovery. 1) each inet_peer struct consumes 192 bytes 2) inetpeer cache uses a binary tree of inet_peer structs, with a nominal size of ~66000 elements under load. 3) lookups in this tree are hitting a lot of cache lines, as tree depth is about 20. 4) If server deals with many tcp flows, we have a high probability of not finding the inet_peer, allocating a fresh one, inserting it in the tree with same initial ip_id_count, (cf secure_ip_id()) 5) We garbage collect inet_peer aggressively. IP ID generation do not have to be 'perfect' Goal is trying to avoid duplicates in a short period of time, so that reassembly units have a chance to complete reassembly of fragments belonging to one message before receiving other fragments with a recycled ID. We simply use an array of generators, and a Jenkin hash using the dst IP as a key. ipv6_select_ident() is put back into net/ipv6/ip6_output.c where it belongs (it is only used from this file) secure_ip_id() and secure_ipv6_id() no longer are needed. Rename ip_select_ident_more() to ip_select_ident_segs() to avoid unnecessary decrement/increment of the number of segments. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- drivers/net/ppp/pptp.c | 2 +- include/net/inetpeer.h | 16 +++------------ include/net/ip.h | 40 ++++++++++++++++++++---------------- include/net/ipv6.h | 2 -- include/net/secure_seq.h | 2 -- net/core/secure_seq.c | 25 ----------------------- net/ipv4/igmp.c | 4 ++-- net/ipv4/inetpeer.c | 18 ----------------- net/ipv4/ip_output.c | 7 +++---- net/ipv4/ip_tunnel_core.c | 2 +- net/ipv4/ipmr.c | 2 +- net/ipv4/raw.c | 2 +- net/ipv4/route.c | 45 +++++++++++++++-------------------------- net/ipv4/xfrm4_mode_tunnel.c | 2 +- net/ipv6/ip6_output.c | 12 +++++++++++ net/ipv6/output_core.c | 23 --------------------- net/netfilter/ipvs/ip_vs_xmit.c | 2 +- 17 files changed, 65 insertions(+), 141 deletions(-) -- 1.9.1