Move definitions of struct ip and struct icmp to struct_ip.h.

This was failing to compile to platforms where HAVE_STRUCT_IP is true
but HAVE_STRUCT_ICMP is false, because struct ip was not being defined
(by a system header) before struct icmp.

struct_ip.h

@@ -43,3 +43,113 @@ struct ip {
 #ifndef WIN32
 #include <netinet/ip_icmp.h>
 #endif
+
+#ifndef HAVE_STRUCT_IP
+#define HAVE_STRUCT_IP
+
+/* From Linux glibc, which apparently borrowed it from
+   BSD code.  Slightly modified for portability --fyodor@insecure.org */
+/*
+ * Structure of an internet header, naked of options.
+ */
+struct ip
+  {
+#if WORDS_BIGENDIAN
+    u_int8_t ip_v:4;                    /* version */
+    u_int8_t ip_hl:4;                   /* header length */
+#else
+    u_int8_t ip_hl:4;                   /* header length */
+    u_int8_t ip_v:4;                    /* version */ 
+#endif
+    u_int8_t ip_tos;                    /* type of service */
+    u_short ip_len;                     /* total length */
+    u_short ip_id;                      /* identification */
+    u_short ip_off;                     /* fragment offset field */
+#define IP_RF 0x8000                    /* reserved fragment flag */
+#define IP_DF 0x4000                    /* dont fragment flag */
+#define IP_MF 0x2000                    /* more fragments flag */
+#define IP_OFFMASK 0x1fff               /* mask for fragmenting bits */
+    u_int8_t ip_ttl;                    /* time to live */
+    u_int8_t ip_p;                      /* protocol */
+    u_short ip_sum;                     /* checksum */
+    struct in_addr ip_src, ip_dst;      /* source and dest address */
+  };
+
+#endif /* HAVE_STRUCT_IP */
+
+#ifndef HAVE_STRUCT_ICMP
+#define HAVE_STRUCT_ICMP
+/* From Linux /usr/include/netinet/ip_icmp.h GLIBC */
+
+/*
+ * Internal of an ICMP Router Advertisement
+ */
+struct icmp_ra_addr
+{
+  u_int32_t ira_addr;
+  u_int32_t ira_preference;
+};
+
+struct icmp
+{
+  u_int8_t  icmp_type;  /* type of message, see below */
+  u_int8_t  icmp_code;  /* type sub code */
+  u_int16_t icmp_cksum; /* ones complement checksum of struct */
+  union
+  {
+    struct ih_idseq             /* echo datagram */
+    {
+      u_int16_t icd_id;
+      u_int16_t icd_seq;
+    } ih_idseq;
+    u_int32_t ih_void;
+
+    /* ICMP_UNREACH_NEEDFRAG -- Path MTU Discovery (RFC1191) */
+    struct ih_pmtu
+    {
+      u_int16_t ipm_void;
+      u_int16_t ipm_nextmtu;
+    } ih_pmtu;
+
+    struct ih_rtradv
+    {
+      u_int8_t irt_num_addrs;
+      u_int8_t irt_wpa;
+      u_int16_t irt_lifetime;
+    } ih_rtradv;
+  } icmp_hun;
+  /* Removed icmp_pptr and icmp_gwaddr from union and #defines because they conflict with dnet */
+#define icmp_id         icmp_hun.ih_idseq.icd_id
+#define icmp_seq        icmp_hun.ih_idseq.icd_seq
+#define icmp_void       icmp_hun.ih_void
+#define icmp_pmvoid     icmp_hun.ih_pmtu.ipm_void
+#define icmp_nextmtu    icmp_hun.ih_pmtu.ipm_nextmtu
+#define icmp_num_addrs  icmp_hun.ih_rtradv.irt_num_addrs
+#define icmp_wpa        icmp_hun.ih_rtradv.irt_wpa
+#define icmp_lifetime   icmp_hun.ih_rtradv.irt_lifetime
+  union
+  {
+    struct
+    {
+      u_int32_t its_otime;
+      u_int32_t its_rtime;
+      u_int32_t its_ttime;
+    } id_ts;
+    struct
+    {
+      struct ip idi_ip;
+      /* options and then 64 bits of data */
+    } id_ip;
+    struct icmp_ra_addr id_radv;
+    u_int32_t   id_mask;
+    u_int8_t    id_data[1];
+  } icmp_dun;
+#define icmp_otime      icmp_dun.id_ts.its_otime
+#define icmp_rtime      icmp_dun.id_ts.its_rtime
+#define icmp_ttime      icmp_dun.id_ts.its_ttime
+#define icmp_ip         icmp_dun.id_ip.idi_ip
+#define icmp_radv       icmp_dun.id_radv
+#define icmp_mask       icmp_dun.id_mask
+#define icmp_data       icmp_dun.id_data
+};
+#endif /* HAVE_STRUCT_ICMP */