diff --git a/CHANGELOG b/CHANGELOG
index 75fd6115..110d940c 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -600,6 +600,11 @@ HISTORY
 
   ++ Bug fixes:
 
+  2008-03-17 Frédéric Bernon, Ed Kerekes
+  * igmp.h, igmp.c: Fix bug #22613 "IGMP iphdr problem" (could have
+    some problems to fill the IP header on some targets, use now the
+    ip.h macros to do it).
+
   2008-03-13 Frédéric Bernon
   * sockets.c: Fix bug #22435 "lwip_recvfrom with TCP break;". Using
     (lwip_)recvfrom with valid "from" and "fromlen" parameters, on a
diff --git a/src/core/ipv4/igmp.c b/src/core/ipv4/igmp.c
index 7a72b353..fb54cc9a 100644
--- a/src/core/ipv4/igmp.c
+++ b/src/core/ipv4/igmp.c
@@ -350,7 +350,7 @@ igmp_input(struct pbuf *p, struct netif *inp, struct ip_addr *dest)
 
   /* Note that the length CAN be greater than 8 but only 8 are used - All are included in the checksum */    
   iphdr = p->payload;
-  if (pbuf_header(p, -(IPH_HL(iphdr) * 4)) || (p->len < IGMP_MINLEN)) {
+  if (pbuf_header(p, -(s16_t)(IPH_HL(iphdr) * 4)) || (p->len < IGMP_MINLEN)) {
     pbuf_free(p);
     IGMP_STATS_INC(igmp.lenerr);
     LWIP_DEBUGF(IGMP_DEBUG, ("igmp_input: length error\n"));
@@ -707,8 +707,8 @@ igmp_ip_output_if(struct pbuf *p, struct ip_addr *src, struct ip_addr *dest,
 
   /* This is the "router alert" option */
   ra    = p->payload;
-  ra[0] = htons (0x9404);
-  ra[1] = 0x0000;
+  ra[0] = htons (ROUTER_ALERT);
+  ra[1] = 0x0000; /* Router shall examine packet */
 
   /* now the normal ip header */
   if (pbuf_header(p, IP_HLEN)) {
@@ -717,23 +717,20 @@ igmp_ip_output_if(struct pbuf *p, struct ip_addr *src, struct ip_addr *dest,
   }
 
   iphdr = p->payload;
+
+  /* Should the IP header be generated or is it already included in p? */
   if (dest != IP_HDRINCL) {
-    iphdr->_ttl_proto = (proto<<8);
-    iphdr->_ttl_proto |= ttl;
+    /** @todo should be shared with ip.c - ip_output_if */
+    IPH_TTL_SET(iphdr, ttl);
+    IPH_PROTO_SET(iphdr, proto);
 
-    /*  iphdr->dest = dest->addr; */
     ip_addr_set(&(iphdr->dest), dest);
-#ifdef HAVE_BITFIELDS
-    iphdr->_v_hl_tos |= ((IP_HLEN+ ROUTER_ALERTLEN)/4)<<16;
-    iphdr->_v_hl_tos |= 4<<24;
-#else
-    iphdr->_v_hl_tos = (4 << 4) | ((IP_HLEN + ROUTER_ALERTLEN)/ 4 & 0xf);
-#endif /* HAVE_BITFIELDS */
 
-    iphdr->_v_hl_tos |= 0;
-    iphdr->_len       = htons(p->tot_len);
-    iphdr->_offset    = htons(0);
-    iphdr->_id        = htons(ip_id++);
+    IPH_VHLTOS_SET(iphdr, 4, ((IP_HLEN + ROUTER_ALERTLEN) / 4), 0/*tos*/);
+    IPH_LEN_SET(iphdr, htons(p->tot_len));
+    IPH_OFFSET_SET(iphdr, 0);
+    IPH_ID_SET(iphdr, htons(ip_id));
+    ++ip_id;
 
     if (ip_addr_isany(src)) {
       ip_addr_set(&(iphdr->src), &(netif->ip_addr));
@@ -741,8 +738,10 @@ igmp_ip_output_if(struct pbuf *p, struct ip_addr *src, struct ip_addr *dest,
       ip_addr_set(&(iphdr->src), src);
     }
 
-    iphdr->_chksum = 0;
-    iphdr->_chksum = inet_chksum(iphdr, IP_HLEN + ROUTER_ALERTLEN);
+    IPH_CHKSUM_SET(iphdr, 0);
+#if CHECKSUM_GEN_IP
+    IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, (IP_HLEN + ROUTER_ALERTLEN)));
+#endif
   } else {
     dest = &(iphdr->dest);
   }
@@ -770,7 +769,7 @@ igmp_send(struct igmp_group *group, u8_t type)
   struct ip_addr   src  = {0};
   struct ip_addr*  dest = NULL;
 
-  /* IP header + IGMP header */
+  /* IP header + "router alert" option + IGMP header */
   p = pbuf_alloc(PBUF_TRANSPORT, IGMP_MINLEN, PBUF_RAM);
   
   if (p) {
diff --git a/src/include/ipv4/lwip/igmp.h b/src/include/ipv4/lwip/igmp.h
index f27e99ff..59c933f3 100644
--- a/src/include/ipv4/lwip/igmp.h
+++ b/src/include/ipv4/lwip/igmp.h
@@ -52,6 +52,7 @@ extern "C" {
 #define IP_PROTO_IGMP                  2
 #define IGMP_TTL                       1
 #define IGMP_MINLEN                    8
+#define ROUTER_ALERT                   0x9404
 #define ROUTER_ALERTLEN                4
 
 /*
@@ -79,12 +80,20 @@ extern "C" {
 /*
  * IGMP packet format.
  */
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/bpstruct.h"
+#endif
+PACK_STRUCT_BEGIN
 struct igmp_msg {
- u8_t           igmp_msgtype;
- u8_t           igmp_maxresp;
- u16_t          igmp_checksum;
- struct ip_addr igmp_group_address;
-};
+ PACK_STRUCT_FIELD(u8_t           igmp_msgtype);
+ PACK_STRUCT_FIELD(u8_t           igmp_maxresp);
+ PACK_STRUCT_FIELD(u16_t          igmp_checksum);
+ PACK_STRUCT_FIELD(struct ip_addr igmp_group_address);
+} PACK_STRUCT_STRUCT;
+PACK_STRUCT_END
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/epstruct.h"
+#endif
 
 /* 
  * now a group structure - there is