diff options
| -rw-r--r-- | include/net/inetpeer.h | 31 | ||||
| -rw-r--r-- | net/ipv4/inetpeer.c | 4 | ||||
| -rw-r--r-- | net/ipv4/route.c | 1 | ||||
| -rw-r--r-- | net/ipv4/tcp_ipv4.c | 11 |
4 files changed, 36 insertions, 11 deletions
diff --git a/include/net/inetpeer.h b/include/net/inetpeer.h index 6174047..417d0c8 100644 --- a/include/net/inetpeer.h +++ b/include/net/inetpeer.h @@ -22,11 +22,21 @@ struct inet_peer { __u32 dtime; /* the time of last use of not * referenced entries */ atomic_t refcnt; - atomic_t rid; /* Frag reception counter */ - atomic_t ip_id_count; /* IP ID for the next packet */ - __u32 tcp_ts; - __u32 tcp_ts_stamp; - struct rcu_head rcu; + /* + * Once inet_peer is queued for deletion (refcnt == -1), following fields + * are not available: rid, ip_id_count, tcp_ts, tcp_ts_stamp + * We can share memory with rcu_head to keep inet_peer small + * (less then 64 bytes) + */ + union { + struct { + atomic_t rid; /* Frag reception counter */ + atomic_t ip_id_count; /* IP ID for the next packet */ + __u32 tcp_ts; + __u32 tcp_ts_stamp; + }; + struct rcu_head rcu; + }; }; void inet_initpeers(void) __init; @@ -37,10 +47,21 @@ struct inet_peer *inet_getpeer(__be32 daddr, int create); /* can be called from BH context or outside */ extern void inet_putpeer(struct inet_peer *p); +/* + * temporary check to make sure we dont access rid, ip_id_count, tcp_ts, + * tcp_ts_stamp if no refcount is taken on inet_peer + */ +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 __u16 inet_getid(struct inet_peer *p, int more) { more++; + inet_peer_refcheck(p); return atomic_add_return(more, &p->ip_id_count) - more; } diff --git a/net/ipv4/inetpeer.c b/net/ipv4/inetpeer.c index 349249f..9ffa24b 100644 --- a/net/ipv4/inetpeer.c +++ b/net/ipv4/inetpeer.c @@ -64,7 +64,7 @@ * usually under some other lock to prevent node disappearing * dtime: unused node list lock * v4daddr: unchangeable - * ip_id_count: idlock + * ip_id_count: atomic value (no lock needed) */ static struct kmem_cache *peer_cachep __read_mostly; @@ -129,7 +129,7 @@ void __init inet_initpeers(void) peer_cachep = kmem_cache_create("inet_peer_cache", sizeof(struct inet_peer), - 0, SLAB_PANIC, + 0, SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL); /* All the timers, started at system startup tend diff --git a/net/ipv4/route.c b/net/ipv4/route.c index a291edb..03430de 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -2881,6 +2881,7 @@ static int rt_fill_info(struct net *net, error = rt->dst.error; expires = rt->dst.expires ? rt->dst.expires - jiffies : 0; if (rt->peer) { + inet_peer_refcheck(rt->peer); id = atomic_read(&rt->peer->ip_id_count) & 0xffff; if (rt->peer->tcp_ts_stamp) { ts = rt->peer->tcp_ts; diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 7f9515c..2e41e6f 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -204,10 +204,12 @@ int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) * TIME-WAIT * and initialize rx_opt.ts_recent from it, * when trying new connection. */ - if (peer != NULL && - (u32)get_seconds() - peer->tcp_ts_stamp <= TCP_PAWS_MSL) { - tp->rx_opt.ts_recent_stamp = peer->tcp_ts_stamp; - tp->rx_opt.ts_recent = peer->tcp_ts; + if (peer) { + inet_peer_refcheck(peer); + if ((u32)get_seconds() - peer->tcp_ts_stamp <= TCP_PAWS_MSL) { + tp->rx_opt.ts_recent_stamp = peer->tcp_ts_stamp; + tp->rx_opt.ts_recent = peer->tcp_ts; + } } } @@ -1351,6 +1353,7 @@ int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb) (dst = inet_csk_route_req(sk, req)) != NULL && (peer = rt_get_peer((struct rtable *)dst)) != NULL && peer->v4daddr == saddr) { + inet_peer_refcheck(peer); if ((u32)get_seconds() - peer->tcp_ts_stamp < TCP_PAWS_MSL && (s32)(peer->tcp_ts - req->ts_recent) > TCP_PAWS_WINDOW) { |