diff options
| -rw-r--r-- | Documentation/networking/ip-sysctl.rst | 14 | ||||
| -rw-r--r-- | include/net/flow_dissector.h | 2 | ||||
| -rw-r--r-- | include/net/ip_fib.h | 23 | ||||
| -rw-r--r-- | include/net/netns/ipv4.h | 8 | ||||
| -rw-r--r-- | net/core/flow_dissector.c | 7 | ||||
| -rw-r--r-- | net/ipv4/sysctl_net_ipv4.c | 66 |
6 files changed, 119 insertions, 1 deletions
diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst index 6e99eccdb837..3616389c8c2d 100644 --- a/Documentation/networking/ip-sysctl.rst +++ b/Documentation/networking/ip-sysctl.rst @@ -131,6 +131,20 @@ fib_multipath_hash_fields - UNSIGNED INTEGER Default: 0x0007 (source IP, destination IP and IP protocol) +fib_multipath_hash_seed - UNSIGNED INTEGER + The seed value used when calculating hash for multipath routes. Applies + to both IPv4 and IPv6 datapath. Only present for kernels built with + CONFIG_IP_ROUTE_MULTIPATH enabled. + + When set to 0, the seed value used for multipath routing defaults to an + internal random-generated one. + + The actual hashing algorithm is not specified -- there is no guarantee + that a next hop distribution effected by a given seed will keep stable + across kernel versions. + + Default: 0 (random) + fib_sync_mem - UNSIGNED INTEGER Amount of dirty memory from fib entries that can be backlogged before synchronize_rcu is forced. diff --git a/include/net/flow_dissector.h b/include/net/flow_dissector.h index 99626475c3f4..3e47e123934d 100644 --- a/include/net/flow_dissector.h +++ b/include/net/flow_dissector.h @@ -442,6 +442,8 @@ static inline bool flow_keys_have_l4(const struct flow_keys *keys) } u32 flow_hash_from_keys(struct flow_keys *keys); +u32 flow_hash_from_keys_seed(struct flow_keys *keys, + const siphash_key_t *keyval); void skb_flow_get_icmp_tci(const struct sk_buff *skb, struct flow_dissector_key_icmp *key_icmp, const void *data, int thoff, int hlen); diff --git a/include/net/ip_fib.h b/include/net/ip_fib.h index b8b3c07e8f7b..6e7984bfb986 100644 --- a/include/net/ip_fib.h +++ b/include/net/ip_fib.h @@ -520,13 +520,34 @@ void fib_nhc_update_mtu(struct fib_nh_common *nhc, u32 new, u32 orig); #ifdef CONFIG_IP_ROUTE_MULTIPATH int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4, const struct sk_buff *skb, struct flow_keys *flkeys); -#endif + +static void +fib_multipath_hash_construct_key(siphash_key_t *key, u32 mp_seed) +{ + u64 mp_seed_64 = mp_seed; + + key->key[0] = (mp_seed_64 << 32) | mp_seed_64; + key->key[1] = key->key[0]; +} static inline u32 fib_multipath_hash_from_keys(const struct net *net, struct flow_keys *keys) { + siphash_aligned_key_t hash_key; + u32 mp_seed; + + mp_seed = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_seed).mp_seed; + fib_multipath_hash_construct_key(&hash_key, mp_seed); + + return flow_hash_from_keys_seed(keys, &hash_key); +} +#else +static inline u32 fib_multipath_hash_from_keys(const struct net *net, + struct flow_keys *keys) +{ return flow_hash_from_keys(keys); } +#endif int fib_check_nh(struct net *net, struct fib_nh *nh, u32 table, u8 scope, struct netlink_ext_ack *extack); diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h index a91bb971f901..5fcd61ada622 100644 --- a/include/net/netns/ipv4.h +++ b/include/net/netns/ipv4.h @@ -40,6 +40,13 @@ struct inet_timewait_death_row { struct tcp_fastopen_context; +#ifdef CONFIG_IP_ROUTE_MULTIPATH +struct sysctl_fib_multipath_hash_seed { + u32 user_seed; + u32 mp_seed; +}; +#endif + struct netns_ipv4 { /* Cacheline organization can be found documented in * Documentation/networking/net_cachelines/netns_ipv4_sysctl.rst. @@ -246,6 +253,7 @@ struct netns_ipv4 { #endif #endif #ifdef CONFIG_IP_ROUTE_MULTIPATH + struct sysctl_fib_multipath_hash_seed sysctl_fib_multipath_hash_seed; u32 sysctl_fib_multipath_hash_fields; u8 sysctl_fib_multipath_use_neigh; u8 sysctl_fib_multipath_hash_policy; diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c index e479790db0f7..e64a26379807 100644 --- a/net/core/flow_dissector.c +++ b/net/core/flow_dissector.c @@ -1806,6 +1806,13 @@ u32 flow_hash_from_keys(struct flow_keys *keys) } EXPORT_SYMBOL(flow_hash_from_keys); +u32 flow_hash_from_keys_seed(struct flow_keys *keys, + const siphash_key_t *keyval) +{ + return __flow_hash_from_keys(keys, keyval); +} +EXPORT_SYMBOL(flow_hash_from_keys_seed); + static inline u32 ___skb_get_hash(const struct sk_buff *skb, struct flow_keys *keys, const siphash_key_t *keyval) diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c index bb64c0ef092d..9140d20eb2d4 100644 --- a/net/ipv4/sysctl_net_ipv4.c +++ b/net/ipv4/sysctl_net_ipv4.c @@ -464,6 +464,61 @@ static int proc_fib_multipath_hash_fields(struct ctl_table *table, int write, return ret; } + +static u32 proc_fib_multipath_hash_rand_seed __ro_after_init; + +static void proc_fib_multipath_hash_init_rand_seed(void) +{ + get_random_bytes(&proc_fib_multipath_hash_rand_seed, + sizeof(proc_fib_multipath_hash_rand_seed)); +} + +static void proc_fib_multipath_hash_set_seed(struct net *net, u32 user_seed) +{ + struct sysctl_fib_multipath_hash_seed new = { + .user_seed = user_seed, + .mp_seed = (user_seed ? user_seed : + proc_fib_multipath_hash_rand_seed), + }; + + WRITE_ONCE(net->ipv4.sysctl_fib_multipath_hash_seed, new); +} + +static int proc_fib_multipath_hash_seed(struct ctl_table *table, int write, + void *buffer, size_t *lenp, + loff_t *ppos) +{ + struct sysctl_fib_multipath_hash_seed *mphs; + struct net *net = table->data; + struct ctl_table tmp; + u32 user_seed; + int ret; + + mphs = &net->ipv4.sysctl_fib_multipath_hash_seed; + user_seed = mphs->user_seed; + + tmp = *table; + tmp.data = &user_seed; + + ret = proc_douintvec_minmax(&tmp, write, buffer, lenp, ppos); + + if (write && ret == 0) { + proc_fib_multipath_hash_set_seed(net, user_seed); + call_netevent_notifiers(NETEVENT_IPV4_MPATH_HASH_UPDATE, net); + } + + return ret; +} +#else + +static void proc_fib_multipath_hash_init_rand_seed(void) +{ +} + +static void proc_fib_multipath_hash_set_seed(struct net *net, u32 user_seed) +{ +} + #endif static struct ctl_table ipv4_table[] = { @@ -1072,6 +1127,13 @@ static struct ctl_table ipv4_net_table[] = { .extra1 = SYSCTL_ONE, .extra2 = &fib_multipath_hash_fields_all_mask, }, + { + .procname = "fib_multipath_hash_seed", + .data = &init_net, + .maxlen = sizeof(u32), + .mode = 0644, + .proc_handler = proc_fib_multipath_hash_seed, + }, #endif { .procname = "ip_unprivileged_port_start", @@ -1550,6 +1612,8 @@ static __net_init int ipv4_sysctl_init_net(struct net *net) if (!net->ipv4.sysctl_local_reserved_ports) goto err_ports; + proc_fib_multipath_hash_set_seed(net, 0); + return 0; err_ports: @@ -1584,6 +1648,8 @@ static __init int sysctl_ipv4_init(void) if (!hdr) return -ENOMEM; + proc_fib_multipath_hash_init_rand_seed(); + if (register_pernet_subsys(&ipv4_sysctl_ops)) { unregister_net_sysctl_table(hdr); return -ENOMEM; |