From fab107a9dfd03d6620b5d074afd27ca6645f25f5 Mon Sep 17 00:00:00 2001
From: likewise <likewise>
Date: Thu, 25 Nov 2004 11:10:53 +0000
Subject: [PATCH] DECLINE message was unicast instead of broadcast

---
 src/core/dhcp.c                 | 6 ++++--
 src/core/udp.c                  | 9 ++++++---
 src/include/ipv4/lwip/ip_addr.h | 8 ++++++++
 3 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/src/core/dhcp.c b/src/core/dhcp.c
index 69337567..2a9c1887 100644
--- a/src/core/dhcp.c
+++ b/src/core/dhcp.c
@@ -679,8 +679,10 @@ static err_t dhcp_decline(struct netif *netif)
     pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len);
 
     udp_bind(dhcp->pcb, IP_ADDR_ANY, DHCP_CLIENT_PORT);
-    udp_connect(dhcp->pcb, &dhcp->server_ip_addr, DHCP_SERVER_PORT);
-    udp_send(dhcp->pcb, dhcp->p_out);
+    /* @todo: should we really connect here? we are performing sendto() */
+    udp_connect(dhcp->pcb, IP_ADDR_ANY, DHCP_SERVER_PORT);
+    /* per section 4.4.4, broadcast DECLINE messages */
+    udp_sendto(dhcp->pcb, dhcp->p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT);
     dhcp_delete_request(netif);
     LWIP_DEBUGF(DHCP_DEBUG | DBG_TRACE | DBG_STATE, ("dhcp_decline: BACKING OFF\n"));
   } else {
diff --git a/src/core/udp.c b/src/core/udp.c
index 43fae895..8343d34d 100644
--- a/src/core/udp.c
+++ b/src/core/udp.c
@@ -356,9 +356,10 @@ udp_sendto(struct udp_pcb *pcb, struct pbuf *p,
   struct ip_addr *dst_ip, u16_t dst_port)
 {
   err_t err;
+  /* temporary space for current PCB remote address */
   struct ip_addr pcb_remote_ip;
   u16_t pcb_remote_port;
-  /* remember remote peer address of PCB */
+  /* remember current remote peer address of PCB */
   pcb_remote_ip.addr = pcb->remote_ip.addr;
   pcb_remote_port = pcb->remote_port;
   /* copy packet destination address to PCB remote peer address */
@@ -366,7 +367,7 @@ udp_sendto(struct udp_pcb *pcb, struct pbuf *p,
   pcb->remote_port = dst_port;
   /* send to the packet destination address */
   err = udp_send(pcb, p);
-  /* reset PCB remote peer address */
+  /* restore PCB remote peer address */
   pcb->remote_ip.addr = pcb_remote_ip.addr;
   pcb->remote_port = pcb_remote_port;
   return err;
@@ -433,7 +434,9 @@ udp_send(struct udp_pcb *pcb, struct pbuf *p)
   udphdr->chksum = 0x0000; 
 
   /* find the outgoing network interface for this packet */
-  if ((netif = ip_route(&(pcb->remote_ip))) == NULL) {
+  netif = ip_route(&(pcb->remote_ip));
+  /* no outgoing network interface could be found? */
+  if (netif == NULL) {
     LWIP_DEBUGF(UDP_DEBUG | 1, ("udp_send: No route to 0x%lx\n", pcb->remote_ip.addr));
     UDP_STATS_INC(udp.rterr);
     return ERR_RTE;
diff --git a/src/include/ipv4/lwip/ip_addr.h b/src/include/ipv4/lwip/ip_addr.h
index 7ac4954b..58820bdf 100644
--- a/src/include/ipv4/lwip/ip_addr.h
+++ b/src/include/ipv4/lwip/ip_addr.h
@@ -117,6 +117,14 @@ extern const struct ip_addr ip_addr_broadcast;
 #define ip_addr_set(dest, src) (dest)->addr = \
                                ((src) == NULL? 0:\
                                (src)->addr)
+/**
+ * Determine if two address are on the same network.
+ *
+ * @arg addr1 IP address 1
+ * @arg addr2 IP address 2
+ * @arg mask network identifier mask
+ * @return !0 if the network identifiers of both address match
+ */
 #define ip_addr_maskcmp(addr1, addr2, mask) (((addr1)->addr & \
                                               (mask)->addr) == \
                                              ((addr2)->addr & \