ppp: support adaptive LCP echos

Port Debians adaptive LCP echo patch to pppd, make it configurable with UCI
and enable it by default.

When adaptive LCP echo is enabled, LCP echo requests are only sent if the
link is idle, this avoids the common situation where a congested PPP link
(e.g. during torrenting) is falsely detected as disconnected because the
LCP replies are not received in time.

Also bump the copyright year in the Makefile, remove a redundant maintainer
entry and fix the shell processing of the keepalive option when the two-
value syntax is used.

Signed-off-by: Jo-Philipp Wich <jow@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@43143 3c298f89-4303-0410-b956-a3cf2f4a3e73

4 files changed, 68 insertions, 9 deletions

diff --git a/package/network/services/ppp/Makefile b/package/network/services/ppp/Makefile
index a26850caf9..6faff4e447 100644
--- a/package/network/services/ppp/Makefile
+++ b/package/network/services/ppp/Makefile
@@ -1,5 +1,5 @@
 #
-# Copyright (C) 2006-2012 OpenWrt.org
+# Copyright (C) 2006-2014 OpenWrt.org
 #
 # This is free software, licensed under the GNU General Public License v2.
 # See /LICENSE for more information.
@@ -10,7 +10,7 @@ include $(INCLUDE_DIR)/kernel.mk
 
 PKG_NAME:=ppp
 PKG_VERSION:=2.4.7
-PKG_RELEASE:=3
+PKG_RELEASE:=4
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
 PKG_SOURCE_URL:=ftp://ftp.samba.org/pub/ppp/
@@ -29,7 +29,6 @@ include $(INCLUDE_DIR)/package.mk
 define Package/ppp/Default
   SECTION:=net
   CATEGORY:=Network
-  MAINTAINER:=Jo-Philipp Wich <xm@subsignal.org>
   URL:=http://ppp.samba.org/
 endef
 
diff --git a/package/network/services/ppp/files/ppp.sh b/package/network/services/ppp/files/ppp.sh
index 0456fda5d9..28cdb9cbd6 100755
--- a/package/network/services/ppp/files/ppp.sh
+++ b/package/network/services/ppp/files/ppp.sh
@@ -12,6 +12,7 @@ ppp_generic_init_config() {
 	proto_config_add_string username
 	proto_config_add_string password
 	proto_config_add_string keepalive
+	proto_config_add_boolean keepalive_adaptive
 	proto_config_add_int demand
 	proto_config_add_string pppd_options
 	proto_config_add_string 'connect:file'
@@ -25,7 +26,7 @@ ppp_generic_init_config() {
 ppp_generic_setup() {
 	local config="$1"; shift
 
-	json_get_vars ipv6 demand keepalive username password pppd_options pppname
+	json_get_vars ipv6 demand keepalive keepalive_adaptive username password pppd_options pppname
 	if [ "$ipv6" = 0 ]; then
 		ipv6=""
 	elif [ -z "$ipv6" -o "$ipv6" = auto ]; then
@@ -38,19 +39,22 @@ ppp_generic_setup() {
 	else
 		demand="persist"
 	fi
-	[ "${keepalive:-0}" -lt 1 ] && keepalive=""
 	[ -n "$mtu" ] || json_get_var mtu mtu
 	[ -n "$pppname" ] || pppname="${proto:-ppp}-$config"
 
-	local interval="${keepalive##*[, ]}"
-	[ "$interval" != "$keepalive" ] || interval=5
+	local lcp_failure="${keepalive%%[, ]*}"
+	local lcp_interval="${keepalive##*[, ]}"
+	local lcp_adaptive="lcp-echo-adaptive"
+	[ "${lcp_failure:-0}" -lt 1 ] && lcp_failure=""
+	[ "$lcp_interval" != "$keepalive" ] || lcp_interval=5
+	[ "${keepalive_adaptive:-1}" -lt 1 ] && lcp_adaptive=""
 	[ -n "$connect" ] || json_get_var connect connect
 	[ -n "$disconnect" ] || json_get_var disconnect disconnect
 
 	proto_run_command "$config" /usr/sbin/pppd \
 		nodetach ipparam "$config" \
 		ifname "$pppname" \
-		${keepalive:+lcp-echo-interval $interval lcp-echo-failure ${keepalive%%[, ]*}} \
+		${lcp_failure:+lcp-echo-interval $lcp_interval lcp-echo-failure $lcp_failure $lcp_adaptive} \
 		${ipv6:++ipv6} \
 		nodefaultroute \
 		usepeerdns \
diff --git a/package/network/services/ppp/patches/121-debian_adaptive_lcp_echo.patch b/package/network/services/ppp/patches/121-debian_adaptive_lcp_echo.patch
new file mode 100644
index 0000000000..b7a62406d0
--- /dev/null
+++ b/package/network/services/ppp/patches/121-debian_adaptive_lcp_echo.patch
@@ -0,0 +1,56 @@
+--- a/pppd/lcp.c
++++ b/pppd/lcp.c
+@@ -73,6 +73,7 @@ static void lcp_delayed_up __P((void *))
+  */
+ int	lcp_echo_interval = 0; 	/* Interval between LCP echo-requests */
+ int	lcp_echo_fails = 0;	/* Tolerance to unanswered echo-requests */
++bool	lcp_echo_adaptive = 0;	/* request echo only if the link was idle */
+ bool	lax_recv = 0;		/* accept control chars in asyncmap */
+ bool	noendpoint = 0;		/* don't send/accept endpoint discriminator */
+ 
+@@ -151,6 +152,8 @@ static option_t lcp_option_list[] = {
+       OPT_PRIO },
+     { "lcp-echo-interval", o_int, &lcp_echo_interval,
+       "Set time in seconds between LCP echo requests", OPT_PRIO },
++    { "lcp-echo-adaptive", o_bool, &lcp_echo_adaptive,
++      "Suppress LCP echo requests if traffic was received", 1 },
+     { "lcp-restart", o_int, &lcp_fsm[0].timeouttime,
+       "Set time in seconds between LCP retransmissions", OPT_PRIO },
+     { "lcp-max-terminate", o_int, &lcp_fsm[0].maxtermtransmits,
+@@ -2331,6 +2334,22 @@ LcpSendEchoRequest (f)
+ 	}
+     }
+ 
++    /*
++     * If adaptive echos have been enabled, only send the echo request if
++     * no traffic was received since the last one.
++     */
++    if (lcp_echo_adaptive) {
++	static unsigned int last_pkts_in = 0;
++
++	update_link_stats(f->unit);
++	link_stats_valid = 0;
++
++	if (link_stats.pkts_in != last_pkts_in) {
++	    last_pkts_in = link_stats.pkts_in;
++	    return;
++	}
++    }
++
+     /*
+      * Make and send the echo request frame.
+      */
+--- a/pppd/pppd.8
++++ b/pppd/pppd.8
+@@ -563,6 +563,11 @@ to 1) if the \fIproxyarp\fR option is us
+ dynamic IP address option (i.e. set /proc/sys/net/ipv4/ip_dynaddr to
+ 1) in demand mode if the local address changes.
+ .TP
++.B lcp\-echo\-adaptive
++If this option is used with the \fIlcp\-echo\-failure\fR option then
++pppd will send LCP echo\-request frames only if no traffic was received
++from the peer since the last echo\-request was sent.
++.TP
+ .B lcp\-echo\-failure \fIn
+ If this option is given, pppd will presume the peer to be dead
+ if \fIn\fR LCP echo\-requests are sent without receiving a valid LCP
diff --git a/package/network/services/ppp/patches/207-lcp_mtu_max.patch b/package/network/services/ppp/patches/207-lcp_mtu_max.patch
index 285865ff5c..240701b585 100644
--- a/package/network/services/ppp/patches/207-lcp_mtu_max.patch
+++ b/package/network/services/ppp/patches/207-lcp_mtu_max.patch
@@ -8,7 +8,7 @@ Signed-off-by: Jo-Philipp Wich <jow@openwrt.org>
 
 --- a/pppd/lcp.c
 +++ b/pppd/lcp.c
-@@ -1914,12 +1914,12 @@ lcp_up(f)
+@@ -1917,12 +1917,12 @@ lcp_up(f)
       * the interface MTU is set to the lowest of that, the
       * MTU we want to use, and our link MRU.
       */