diff options
| -rw-r--r-- | include/net/inet_connection_sock.h | 3 | ||||
| -rw-r--r-- | include/net/tcp.h | 9 | ||||
| -rw-r--r-- | net/ipv4/tcp_cong.c | 97 |
3 files changed, 91 insertions, 18 deletions
diff --git a/include/net/inet_connection_sock.h b/include/net/inet_connection_sock.h index 848e85cb5c61..5976bdecf58b 100644 --- a/include/net/inet_connection_sock.h +++ b/include/net/inet_connection_sock.h @@ -98,7 +98,8 @@ struct inet_connection_sock { const struct tcp_congestion_ops *icsk_ca_ops; const struct inet_connection_sock_af_ops *icsk_af_ops; unsigned int (*icsk_sync_mss)(struct sock *sk, u32 pmtu); - __u8 icsk_ca_state; + __u8 icsk_ca_state:7, + icsk_ca_dst_locked:1; __u8 icsk_retransmits; __u8 icsk_pending; __u8 icsk_backoff; diff --git a/include/net/tcp.h b/include/net/tcp.h index f50f29faf76f..135b70c9a734 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -787,6 +787,8 @@ enum tcp_ca_ack_event_flags { #define TCP_CA_MAX 128 #define TCP_CA_BUF_MAX (TCP_CA_NAME_MAX*TCP_CA_MAX) +#define TCP_CA_UNSPEC 0 + /* Algorithm can be set on socket without CAP_NET_ADMIN privileges */ #define TCP_CONG_NON_RESTRICTED 0x1 /* Requires ECN/ECT set on all packets */ @@ -794,7 +796,8 @@ enum tcp_ca_ack_event_flags { struct tcp_congestion_ops { struct list_head list; - unsigned long flags; + u32 key; + u32 flags; /* initialize private data (optional) */ void (*init)(struct sock *sk); @@ -841,6 +844,10 @@ u32 tcp_reno_ssthresh(struct sock *sk); void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 acked); extern struct tcp_congestion_ops tcp_reno; +struct tcp_congestion_ops *tcp_ca_find_key(u32 key); +u32 tcp_ca_get_key_by_name(const char *name); +char *tcp_ca_get_name_by_key(u32 key, char *buffer); + static inline bool tcp_ca_needs_ecn(const struct sock *sk) { const struct inet_connection_sock *icsk = inet_csk(sk); diff --git a/net/ipv4/tcp_cong.c b/net/ipv4/tcp_cong.c index 38f2f8aa4ceb..63c29dba68a8 100644 --- a/net/ipv4/tcp_cong.c +++ b/net/ipv4/tcp_cong.c @@ -13,6 +13,7 @@ #include <linux/types.h> #include <linux/list.h> #include <linux/gfp.h> +#include <linux/jhash.h> #include <net/tcp.h> static DEFINE_SPINLOCK(tcp_cong_list_lock); @@ -31,6 +32,34 @@ static struct tcp_congestion_ops *tcp_ca_find(const char *name) return NULL; } +/* Must be called with rcu lock held */ +static const struct tcp_congestion_ops *__tcp_ca_find_autoload(const char *name) +{ + const struct tcp_congestion_ops *ca = tcp_ca_find(name); +#ifdef CONFIG_MODULES + if (!ca && capable(CAP_NET_ADMIN)) { + rcu_read_unlock(); + request_module("tcp_%s", name); + rcu_read_lock(); + ca = tcp_ca_find(name); + } +#endif + return ca; +} + +/* Simple linear search, not much in here. */ +struct tcp_congestion_ops *tcp_ca_find_key(u32 key) +{ + struct tcp_congestion_ops *e; + + list_for_each_entry_rcu(e, &tcp_cong_list, list) { + if (e->key == key) + return e; + } + + return NULL; +} + /* * Attach new congestion control algorithm to the list * of available options. @@ -45,9 +74,12 @@ int tcp_register_congestion_control(struct tcp_congestion_ops *ca) return -EINVAL; } + ca->key = jhash(ca->name, sizeof(ca->name), strlen(ca->name)); + spin_lock(&tcp_cong_list_lock); - if (tcp_ca_find(ca->name)) { - pr_notice("%s already registered\n", ca->name); + if (ca->key == TCP_CA_UNSPEC || tcp_ca_find_key(ca->key)) { + pr_notice("%s already registered or non-unique key\n", + ca->name); ret = -EEXIST; } else { list_add_tail_rcu(&ca->list, &tcp_cong_list); @@ -70,9 +102,50 @@ void tcp_unregister_congestion_control(struct tcp_congestion_ops *ca) spin_lock(&tcp_cong_list_lock); list_del_rcu(&ca->list); spin_unlock(&tcp_cong_list_lock); + + /* Wait for outstanding readers to complete before the + * module gets removed entirely. + * + * A try_module_get() should fail by now as our module is + * in "going" state since no refs are held anymore and + * module_exit() handler being called. + */ + synchronize_rcu(); } EXPORT_SYMBOL_GPL(tcp_unregister_congestion_control); +u32 tcp_ca_get_key_by_name(const char *name) +{ + const struct tcp_congestion_ops *ca; + u32 key; + + might_sleep(); + + rcu_read_lock(); + ca = __tcp_ca_find_autoload(name); + key = ca ? ca->key : TCP_CA_UNSPEC; + rcu_read_unlock(); + + return key; +} +EXPORT_SYMBOL_GPL(tcp_ca_get_key_by_name); + +char *tcp_ca_get_name_by_key(u32 key, char *buffer) +{ + const struct tcp_congestion_ops *ca; + char *ret = NULL; + + rcu_read_lock(); + ca = tcp_ca_find_key(key); + if (ca) + ret = strncpy(buffer, ca->name, + TCP_CA_NAME_MAX); + rcu_read_unlock(); + + return ret; +} +EXPORT_SYMBOL_GPL(tcp_ca_get_name_by_key); + /* Assign choice of congestion control. */ void tcp_assign_congestion_control(struct sock *sk) { @@ -253,25 +326,17 @@ out: int tcp_set_congestion_control(struct sock *sk, const char *name) { struct inet_connection_sock *icsk = inet_csk(sk); - struct tcp_congestion_ops *ca; + const struct tcp_congestion_ops *ca; int err = 0; - rcu_read_lock(); - ca = tcp_ca_find(name); + if (icsk->icsk_ca_dst_locked) + return -EPERM; - /* no change asking for existing value */ + rcu_read_lock(); + ca = __tcp_ca_find_autoload(name); + /* No change asking for existing value */ if (ca == icsk->icsk_ca_ops) goto out; - -#ifdef CONFIG_MODULES - /* not found attempt to autoload module */ - if (!ca && capable(CAP_NET_ADMIN)) { - rcu_read_unlock(); - request_module("tcp_%s", name); - rcu_read_lock(); - ca = tcp_ca_find(name); - } -#endif if (!ca) err = -ENOENT; else if (!((ca->flags & TCP_CONG_NON_RESTRICTED) || |