$Id: linux-2.6_freezetcp.patch 1061 2009-06-05 08:49:48Z omehani $ Freeze-TCP patch for Linux 2.6 (Git tree d9244b5). Olivier Mehani ==== diff --git a/include/linux/tcp.h b/include/linux/tcp.h index 9d5078b..006f187 100644 --- a/include/linux/tcp.h +++ b/include/linux/tcp.h @@ -96,6 +96,7 @@ enum { #define TCP_QUICKACK 12 /* Block/reenable quick acks */ #define TCP_CONGESTION 13 /* Congestion control algorithm */ #define TCP_MD5SIG 14 /* TCP MD5 Signature (RFC2385) */ +#define TCP_FREEZE 15 /* Freeze-TCP */ #define TCPI_OPT_TIMESTAMPS 1 #define TCPI_OPT_SACK 2 @@ -408,6 +409,10 @@ struct tcp_sock { #endif int linger2; + +#ifdef CONFIG_TCP_FREEZE + int frozen; +#endif }; static inline struct tcp_sock *tcp_sk(const struct sock *sk) diff --git a/include/net/tcp.h b/include/net/tcp.h index 646dbe3..514fca3 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -531,6 +531,10 @@ static inline void tcp_fast_path_check(struct sock *sk) tcp_fast_path_on(tp); } +/* tcp_freeze.c */ +extern int tcp_set_freeze(struct tcp_sock *sk, int val); +extern int tcp_get_freeze(struct tcp_sock *sk); + /* Compute the actual rto_min value */ static inline u32 tcp_rto_min(struct sock *sk) { diff --git a/net/ipv4/Kconfig b/net/ipv4/Kconfig index 5b919f7..bc15667 100644 --- a/net/ipv4/Kconfig +++ b/net/ipv4/Kconfig @@ -428,6 +428,29 @@ config INET_TCP_DIAG depends on INET_DIAG def_tristate INET_DIAG +config TCP_FREEZE + bool "TCP: Freeze-TCP" + depends on EXPERIMENTAL + default n + help + Support for Freeze-TCP [0] to temporarily freeze the remote sender. + The receiver can send a Zero-Window Advertizement to suspend the + remote peer's sender. This can be used e.g. when the receiver is + mobile and predicts a disconnection to avoid losing packets. + + [0] T. Goff, J. Moronski, D. S. Phatak, and V. Gupta, "Freeze-TCP: a + True End-to-end TCP Enhancement Mechanism for Mobile Environments," + In Proceedings of IEEE INFOCOM 2000. + + If unsure, say N. + +config TCP_FREEZE_DEBUG + bool "TCP: Freeze-TCP debug messages" + depends on TCP_FREEZE + default n + help + Support for debug messages for Freeze-TCP. + menuconfig TCP_CONG_ADVANCED bool "TCP: advanced congestion control" ---help--- diff --git a/net/ipv4/Makefile b/net/ipv4/Makefile index 80ff87c..956d30e 100644 --- a/net/ipv4/Makefile +++ b/net/ipv4/Makefile @@ -48,6 +48,7 @@ obj-$(CONFIG_TCP_CONG_SCALABLE) += tcp_scalable.o obj-$(CONFIG_TCP_CONG_LP) += tcp_lp.o obj-$(CONFIG_TCP_CONG_YEAH) += tcp_yeah.o obj-$(CONFIG_TCP_CONG_ILLINOIS) += tcp_illinois.o +obj-$(CONFIG_TCP_FREEZE) += tcp_freeze.o obj-$(CONFIG_NETLABEL) += cipso_ipv4.o obj-$(CONFIG_XFRM) += xfrm4_policy.o xfrm4_state.o xfrm4_input.o \ diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 7a0f0b2..ffeda89 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -2208,6 +2208,12 @@ static int do_tcp_setsockopt(struct sock *sk, int level, break; #endif +#ifdef CONFIG_TCP_FREEZE + case TCP_FREEZE: + err = tcp_set_freeze(tp, val); + break; +#endif + default: err = -ENOPROTOOPT; break; @@ -2385,6 +2391,13 @@ static int do_tcp_getsockopt(struct sock *sk, int level, if (copy_to_user(optval, icsk->icsk_ca_ops->name, len)) return -EFAULT; return 0; + +#ifdef CONFIG_TCP_FREEZE + case TCP_FREEZE: + val = tcp_get_freeze(tp); + break; +#endif + default: return -ENOPROTOOPT; } @@ -2923,6 +2936,9 @@ void __init tcp_init(void) printk(KERN_INFO "TCP: Hash tables configured " "(established %d bind %d)\n", tcp_hashinfo.ehash_size, tcp_hashinfo.bhash_size); +#ifdef CONFIG_TCP_FREEZE + printk(KERN_INFO "TCP: support for freezing using ZWA\n"); +#endif tcp_register_congestion_control(&tcp_reno); } diff --git a/net/ipv4/tcp_freeze.c b/net/ipv4/tcp_freeze.c new file mode 100644 index 0000000..c3e4ae5 --- /dev/null +++ b/net/ipv4/tcp_freeze.c @@ -0,0 +1,65 @@ +/* + * Freeze-TCP support for Linux + * Copyright (C) 2009 Nicta, Olivier Mehani + * + * net/ipv4/tcp_freeze.c + * + * Helper functions to manipulate the frozen flag of the TCP socket structure + * and send the appropriate messages. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ +#include +#include +#include + + +#ifdef CONFIG_TCP_FREEZE_DEBUG +# define DEBUG(...) printk(KERN_DEBUG __VA_ARGS__) +#else +# define DEBUG(...) /* debug statement */ +#endif + +int tcp_set_freeze(struct tcp_sock *tp, int val) +{ + DEBUG("TCP: %s(%p, %d)\n", __FUNCTION__, tp, val); + if (!val && tcp_get_freeze(tp)) { + DEBUG("TCP: Unfreezing socket...\n"); + tp->frozen = 0; + /* Send ZWA */ + tcp_send_ack((struct sock *) tp); + } else if (val == 1 && !tcp_get_freeze(tp)) { + DEBUG("TCP: Freezing socket...\n"); + tp->frozen = 1; + /* Send dupacks + * TODO: configurable number of AVK via sysctl */ + tcp_send_ack((struct sock *) tp); + tcp_send_ack((struct sock *) tp); + } else { + DEBUG("TCP: Invalid command\n"); + return -EINVAL; + } + + return 0; +} + +int tcp_get_freeze(struct tcp_sock *tp) +{ + /* DEBUG("TCP: %s(%p), %d\n", __FUNCTION__, tp, tp->frozen); */ + return tp->frozen; +} + +EXPORT_SYMBOL(tcp_set_freeze); +EXPORT_SYMBOL(tcp_get_freeze); diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index eec3e6f..eee1b4c 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -3397,6 +3397,13 @@ static int tcp_ack_update_window(struct sock *sk, struct sk_buff *skb, u32 ack, int flag = 0; u32 nwin = ntohs(tcp_hdr(skb)->window); +#ifdef CONFIG_TCP_FREEZE + /* Sender side fix for implementation of Freeze TCP + * (originally from Francis Chai's patch */ + if (nwin < 0) + tp->snd_wnd = 0; +#endif + if (likely(!tcp_hdr(skb)->syn)) nwin <<= tp->rx_opt.snd_wscale; diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c index 43bbba7..0d7fbef 100644 --- a/net/ipv4/tcp_minisocks.c +++ b/net/ipv4/tcp_minisocks.c @@ -475,6 +475,9 @@ struct sock *tcp_create_openreq_child(struct sock *sk, struct request_sock *req, if (newtp->af_specific->md5_lookup(sk, newsk)) newtp->tcp_header_len += TCPOLEN_MD5SIG_ALIGNED; #endif +#ifdef CONFIG_TCP_FREEZE + newtp->frozen = 0; +#endif if (skb->len >= TCP_MIN_RCVMSS+newtp->tcp_header_len) newicsk->icsk_ack.last_seg_size = skb->len - newtp->tcp_header_len; newtp->rx_opt.mss_clamp = req->mss; diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 59aec60..c5f135a 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -244,6 +244,9 @@ static u16 tcp_select_window(struct sock *sk) u32 cur_win = tcp_receive_window(tp); u32 new_win = __tcp_select_window(sk); + if (unlikely(tp->frozen == 1)) + cur_win = new_win = 0; + /* Never shrink the offered window */ if (new_win < cur_win) { /* Danger Will Robinson!