From 3205f823d93b13e44a7d00ea6baae003dbe84362 Mon Sep 17 00:00:00 2001
From: "Nicholas J. Kain" <nicholas@kain.us>
Date: Tue, 5 Jul 2011 15:57:11 -0400
Subject: [PATCH] Handle DS_REBINDING and DS_RENEWING states just like DS_BOUND
 when the hardware link returns after having been lost.

Make the timeout action for DS_BOUND_GW_CHECK perform ARP retransmissions
rather than just sending a single query.
---
 ndhc/arp.c   | 24 +++++++++++++++---------
 ndhc/arp.h   |  3 +--
 ndhc/state.c | 12 +++++++++---
 3 files changed, 25 insertions(+), 14 deletions(-)

diff --git a/ndhc/arp.c b/ndhc/arp.c
index 8f5e643..95d9068 100644
--- a/ndhc/arp.c
+++ b/ndhc/arp.c
@@ -1,5 +1,5 @@
 /* arp.c - arp ping checking
- * Time-stamp: <2011-07-05 15:37:02 njk>
+ * Time-stamp: <2011-07-05 15:54:06 njk>
  *
  * Copyright 2010-2011 Nicholas J. Kain <njkain@gmail.com>
  *
@@ -408,17 +408,21 @@ static void arp_failed(struct client_state_t *cs)
                      0 : RATE_LIMIT_INTERVAL);
 }
 
-void arp_gw_failed(struct client_state_t *cs)
+static void arp_gw_failed(struct client_state_t *cs)
+{
+    log_line("arp: Gateway appears to have changed, getting new lease.");
+    arp_close_fd(cs);
+    cs->oldTimeout = 0;
+    reinit_selecting(cs, 0);
+}
+
+static int act_if_arp_gw_failed(struct client_state_t *cs)
 {
     if (arp_send_stats[ASEND_GW_PING].count >= gw_check_init_pingcount + 3) {
-        log_line("arp: Gateway appears to have changed, getting new lease");
-        arp_close_fd(cs);
-        cs->oldTimeout = 0;
-        reinit_selecting(cs, 0);
-        return;
+        arp_gw_failed(cs);
+        return 1;
     }
-    cs->timeout = ARP_RETRANS_DELAY + 250;
-    arp_retransmit(cs);
+    return 0;
 }
 
 void arp_success(struct client_state_t *cs)
@@ -535,6 +539,8 @@ void arp_retransmit(struct client_state_t *cs)
         }
     }
     if (arpState == AS_GW_CHECK || arpState == AS_GW_QUERY) {
+        if (arpState == AS_GW_CHECK && act_if_arp_gw_failed(cs))
+            return;
         long long cms = curms();
         long long rtts = arp_send_stats[ASEND_GW_PING].ts + ARP_RETRANS_DELAY;
         if (cms < rtts) {
diff --git a/ndhc/arp.h b/ndhc/arp.h
index dcca3c0..3c8d1ab 100644
--- a/ndhc/arp.h
+++ b/ndhc/arp.h
@@ -1,5 +1,5 @@
 /* arp.h - functions to call the interface change daemon
- * Time-stamp: <2011-07-05 13:49:59 njk>
+ * Time-stamp: <2011-07-05 15:54:33 njk>
  *
  * Copyright 2010-2011 Nicholas J. Kain <njkain@gmail.com>
  *
@@ -52,7 +52,6 @@ int arp_close_fd(struct client_state_t *cs);
 int arp_check(struct client_state_t *cs, struct dhcpmsg *packet);
 int arp_gw_check(struct client_state_t *cs);
 void arp_success(struct client_state_t *cs);
-void arp_gw_failed(struct client_state_t *cs);
 void arp_retransmit(struct client_state_t *cs);
 void handle_arp_response(struct client_state_t *cs);
 
diff --git a/ndhc/state.c b/ndhc/state.c
index ea8c2b1..ec46b6b 100644
--- a/ndhc/state.c
+++ b/ndhc/state.c
@@ -23,6 +23,7 @@ static void renewing_timeout(struct client_state_t *cs);
 static void rebinding_timeout(struct client_state_t *cs);
 static void released_timeout(struct client_state_t *cs);
 static void collision_check_timeout(struct client_state_t *cs);
+static void bound_gw_check_timeout(struct client_state_t *cs);
 static void anfrelease(struct client_state_t *cs);
 static void nfrelease(struct client_state_t *cs);
 static void frelease(struct client_state_t *cs);
@@ -42,7 +43,7 @@ dhcp_state_t dhcp_states[] = {
     { 0, bound_timeout, frenew, nfrelease},                  // BOUND
     { an_packet, renewing_timeout, frenew, nfrelease},       // RENEWING
     { an_packet, rebinding_timeout, frenew, nfrelease},      // REBINDING
-    { 0, arp_gw_failed, frenew, anfrelease},                 // BOUND_GW_CHECK
+    { 0, bound_gw_check_timeout, frenew, anfrelease},        // BOUND_GW_CHECK
     { 0, collision_check_timeout, frenew, anfrelease},       // COLLISION_CHECK
     { 0, released_timeout, frenew, frelease},                // RELEASED
     { 0, 0, 0, 0},                                           // NUM_STATES
@@ -162,6 +163,11 @@ static void collision_check_timeout(struct client_state_t *cs)
     arp_retransmit(cs);
 }
 
+static void bound_gw_check_timeout(struct client_state_t *cs)
+{
+    arp_retransmit(cs);
+}
+
 static void an_packet(struct client_state_t *cs, struct dhcpmsg *packet,
                       uint8_t *message)
 {
@@ -294,8 +300,8 @@ void ifup_action(struct client_state_t *cs)
 {
     // If we have a lease, check to see if our gateway is still valid via ARP.
     // If it fails, state -> SELECTING.
-    // XXX what about RENEWING and REBINDING??
-    if (cs->dhcpState == DS_BOUND) {
+    if (cs->dhcpState == DS_BOUND || cs->dhcpState == DS_RENEWING ||
+        cs->dhcpState == DS_REBINDING) {
         if (arp_gw_check(cs) == -1)
             log_warning("nl: arp_gw_check could not make arp socket, assuming lease is still OK");
         else