diff options
| -rw-r--r-- | Documentation/networking/ip-sysctl.txt | 10 | ||||
| -rw-r--r-- | net/ipv4/sysctl_net_ipv4.c | 5 | ||||
| -rw-r--r-- | net/ipv4/tcp_ipv4.c | 35 |
3 files changed, 43 insertions, 7 deletions
diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index 924bd51327b7..6841c74eac00 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -667,11 +667,15 @@ tcp_tso_win_divisor - INTEGER building larger TSO frames. Default: 3 -tcp_tw_reuse - BOOLEAN - Allow to reuse TIME-WAIT sockets for new connections when it is - safe from protocol viewpoint. Default value is 0. +tcp_tw_reuse - INTEGER + Enable reuse of TIME-WAIT sockets for new connections when it is + safe from protocol viewpoint. + 0 - disable + 1 - global enable + 2 - enable for loopback traffic only It should not be changed without advice/request of technical experts. + Default: 2 tcp_window_scaling - BOOLEAN Enable window scaling as defined in RFC1323. diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c index d2eed3ddcb0a..d06247ba08b2 100644 --- a/net/ipv4/sysctl_net_ipv4.c +++ b/net/ipv4/sysctl_net_ipv4.c @@ -30,6 +30,7 @@ static int zero; static int one = 1; +static int two = 2; static int four = 4; static int thousand = 1000; static int gso_max_segs = GSO_MAX_SEGS; @@ -845,7 +846,9 @@ static struct ctl_table ipv4_net_table[] = { .data = &init_net.ipv4.sysctl_tcp_tw_reuse, .maxlen = sizeof(int), .mode = 0644, - .proc_handler = proc_dointvec + .proc_handler = proc_dointvec_minmax, + .extra1 = &zero, + .extra2 = &two, }, { .procname = "tcp_max_tw_buckets", diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 749b0ef9f405..633963e228bc 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -110,8 +110,38 @@ static u32 tcp_v4_init_ts_off(const struct net *net, const struct sk_buff *skb) int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp) { + const struct inet_timewait_sock *tw = inet_twsk(sktw); const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw); struct tcp_sock *tp = tcp_sk(sk); + int reuse = sock_net(sk)->ipv4.sysctl_tcp_tw_reuse; + + if (reuse == 2) { + /* Still does not detect *everything* that goes through + * lo, since we require a loopback src or dst address + * or direct binding to 'lo' interface. + */ + bool loopback = false; + if (tw->tw_bound_dev_if == LOOPBACK_IFINDEX) + loopback = true; +#if IS_ENABLED(CONFIG_IPV6) + if (tw->tw_family == AF_INET6) { + if (ipv6_addr_loopback(&tw->tw_v6_daddr) || + (ipv6_addr_v4mapped(&tw->tw_v6_daddr) && + (tw->tw_v6_daddr.s6_addr[12] == 127)) || + ipv6_addr_loopback(&tw->tw_v6_rcv_saddr) || + (ipv6_addr_v4mapped(&tw->tw_v6_rcv_saddr) && + (tw->tw_v6_rcv_saddr.s6_addr[12] == 127))) + loopback = true; + } else +#endif + { + if (ipv4_is_loopback(tw->tw_daddr) || + ipv4_is_loopback(tw->tw_rcv_saddr)) + loopback = true; + } + if (!loopback) + reuse = 0; + } /* With PAWS, it is safe from the viewpoint of data integrity. Even without PAWS it is safe provided sequence @@ -125,8 +155,7 @@ int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp) and use initial timestamp retrieved from peer table. */ if (tcptw->tw_ts_recent_stamp && - (!twp || (sock_net(sk)->ipv4.sysctl_tcp_tw_reuse && - get_seconds() - tcptw->tw_ts_recent_stamp > 1))) { + (!twp || (reuse && get_seconds() - tcptw->tw_ts_recent_stamp > 1))) { tp->write_seq = tcptw->tw_snd_nxt + 65535 + 2; if (tp->write_seq == 0) tp->write_seq = 1; @@ -2529,7 +2558,7 @@ static int __net_init tcp_sk_init(struct net *net) net->ipv4.sysctl_tcp_orphan_retries = 0; net->ipv4.sysctl_tcp_fin_timeout = TCP_FIN_TIMEOUT; net->ipv4.sysctl_tcp_notsent_lowat = UINT_MAX; - net->ipv4.sysctl_tcp_tw_reuse = 0; + net->ipv4.sysctl_tcp_tw_reuse = 2; cnt = tcp_hashinfo.ehash_mask + 1; net->ipv4.tcp_death_row.sysctl_max_tw_buckets = (cnt + 1) / 2; |