Re: [lwip-users] inet_ntoa implementation

[Marc Boucher]

On Fri, Apr 11, 2003 at 10:50:58AM +0200, Sergio PérezAlcañiz wrote:
> Hello, I'm using the porting of ares in my own lwip porting (RTLinux porting)
> and I find very interesting to have a inet_ntoa implementation. Next lines 
> are a
> simple implementation for that. 
> 
> Include in the file inet.h this line:
> char *inet_ntoa(struct in_addr in);
> 
> 
> and at the end of inet.c:
> 
> 
> static unsigned int i2a(char* dest,unsigned int x) {
>   register unsigned int tmp=x;
>   register unsigned int len=0;
>   if (x>=100) { *dest++=tmp/100+'0'; tmp=tmp%100; ++len; }
>   if (x>=10) { *dest++=tmp/10+'0'; tmp=tmp%10; ++len; }
>   *dest++=tmp+'0';
>   return len+1;
> }
> 
> char *inet_ntoa(struct in_addr in) {
>   static char buf[20];
>   unsigned int len;
>   unsigned char *ip=(unsigned char*)∈
>   len=i2a(buf,ip[0]); buf[len]='.'; ++len;
>   len+=i2a(buf+ len,ip[1]); buf[len]='.'; ++len;
>   len+=i2a(buf+ len,ip[2]); buf[len]='.'; ++len;
>   len+=i2a(buf+ len,ip[3]); buf[len]=0;
>   return buf;
> }
> 
> 
> I think that this is useful for everybody who uses the socket api.
> 
> 
> Regards.
> Sergio.
> 


In the same category, here's inet_aton() and inet_addr();
they are used by the ares DNS resolver under lwIP
and a few other things here..

Marc


diff -ur lwip-cvs-03021900/src/include/ipv6/lwip/inet.h 
lwip-cvs-03021900-mb/src/include/ipv6/lwip/inet.h
--- lwip-cvs-03021900/src/include/ipv6/lwip/inet.h      2003-01-08 
05:09:42.000000000 -0500
+++ lwip-cvs-03021900-mb/src/include/ipv6/lwip/inet.h   2003-02-27 
17:31:42.000000000 -0500
@@ -44,6 +44,8 @@
                         struct ip_addr *src, struct ip_addr *dest,
                         u8_t proto, u32_t proto_len);
 
+u32_t inet_addr(const char *cp);
+int inet_aton(const char *cp, struct in_addr *addr);
 
 #ifndef _MACHINE_ENDIAN_H_
 #ifndef _NETINET_IN_H
diff -ur lwip-cvs-03021900/src/core/inet.c lwip-cvs-03021900-mb/src/core/inet.c
--- lwip-cvs-03021900/src/core/inet.c   2003-02-07 04:16:02.000000000 -0500
+++ lwip-cvs-03021900-mb/src/core/inet.c        2003-02-27 17:31:06.000000000 
-0500
@@ -170,3 +170,122 @@
 
 
 
/*-----------------------------------------------------------------------------------*/
+
+/*
+ * Ascii internet address interpretation routine.
+ * The value returned is in network order.
+ */
+
+/*  */
+/* inet_addr */
+u32_t inet_addr(const char *cp)
+{
+    struct in_addr val;
+
+    if (inet_aton(cp, &val)) {
+        return (val.s_addr);
+    }
+    return (INADDR_NONE);
+}
+
+/* 
+ * Check whether "cp" is a valid ascii representation
+ * of an Internet address and convert to a binary address.
+ * Returns 1 if the address is valid, 0 if not.
+ * This replaces inet_addr, the return value from which
+ * cannot distinguish between failure and a local broadcast address.
+ */
+/*  */
+/* inet_aton */
+int inet_aton(const char *cp, struct in_addr *addr)
+{
+    u32_t val;
+    int base, n;
+    char c;
+//    u_int parts[4];
+//    u_int *pp = parts;
+    u32_t parts[4];
+    u32_t* pp = parts;
+
+    c = *cp;
+    for (;;) {
+        /*
+         * Collect number up to ``.''.
+         * Values are specified as for C:
+         * 0x=hex, 0=octal, isdigit=decimal.
+         */
+        if (!isdigit(c))
+            return (0);
+        val = 0; base = 10;
+        if (c == '0') {
+            c = *++cp;
+            if (c == 'x' || c == 'X')
+                base = 16, c = *++cp;
+            else
+                base = 8;
+        }
+        for (;;) {
+            if (isascii(c) && isdigit(c)) {
+                val = (val * base) + (c - '0');
+                c = *++cp;
+            } else if (base == 16 && isascii(c) && isxdigit(c)) {
+                val = (val << 4) |
+                    (c + 10 - (islower(c) ? 'a' : 'A'));
+                c = *++cp;
+            } else
+            break;
+        }
+        if (c == '.') {
+            /*
+             * Internet format:
+             *  a.b.c.d
+             *  a.b.c   (with c treated as 16 bits)
+             *  a.b (with b treated as 24 bits)
+             */
+            if (pp >= parts + 3)
+                return (0);
+            *pp++ = val;
+            c = *++cp;
+        } else
+            break;
+    }
+    /*
+     * Check for trailing characters.
+     */
+    if (c != '\0' && (!isascii(c) || !isspace(c)))
+        return (0);
+    /*
+     * Concoct the address according to
+     * the number of parts specified.
+     */
+    n = pp - parts + 1;
+    switch (n) {
+
+    case 0:
+        return (0);     /* initial nondigit */
+
+    case 1:             /* a -- 32 bits */
+        break;
+
+    case 2:             /* a.b -- 8.24 bits */
+        if (val > 0xffffff)
+            return (0);
+        val |= parts[0] << 24;
+        break;
+
+    case 3:             /* a.b.c -- 8.8.16 bits */
+        if (val > 0xffff)
+            return (0);
+        val |= (parts[0] << 24) | (parts[1] << 16);
+        break;
+
+    case 4:             /* a.b.c.d -- 8.8.8.8 bits */
+        if (val > 0xff)
+            return (0);
+        val |= (parts[0] << 24) | (parts[1] << 16) | (parts[2] << 8);
+        break;
+    }
+    if (addr)
+        addr->s_addr = htonl(val);
+    return (1);
+}
diff -ur lwip-cvs-03021900/src/include/ipv4/lwip/inet.h 
lwip-cvs-03021900-mb/src/include/ipv4/lwip/inet.h
--- lwip-cvs-03021900/src/include/ipv4/lwip/inet.h      2003-01-08 
05:09:42.000000000 -0500
+++ lwip-cvs-03021900-mb/src/include/ipv4/lwip/inet.h   2003-02-27 
17:31:31.000000000 -0500
@@ -44,6 +44,9 @@
                         struct ip_addr *src, struct ip_addr *dest,
                         u8_t proto, u16_t proto_len);
 
+u32_t inet_addr(const char *cp);
+int inet_aton(const char *cp, struct in_addr *addr);
+
 #ifdef HTONS
 #undef HTONS
 #endif /* HTONS */
diff -ur lwip-cvs-03021900/src/include/ipv4/lwip/ip_addr.h 
lwip-cvs-03021900-mb/src/include/ipv4/lwip/ip_addr.h
--- lwip-cvs-03021900/src/include/ipv4/lwip/ip_addr.h   2003-01-08 
05:09:42.000000000 -0500
+++ lwip-cvs-03021900-mb/src/include/ipv4/lwip/ip_addr.h        2003-02-12 
11:44:30.000000000 -0500
@@ -38,6 +38,42 @@
 
 #define IP_ADDR_BROADCAST (&ip_addr_broadcast)
 
+#define INADDR_NONE            ((u32_t) 0xffffffff)    /* 255.255.255.255 */
+#define INADDR_LOOPBACK                ((u32_t) 0x7f000001)    /* 127.0.0.1 */
+
+/* Definitions of the bits in an Internet address integer.
+
+   On subnets, host and network parts are found according to
+   the subnet mask, not these masks.  */
+
+#define        IN_CLASSA(a)            ((((u32_t)(a)) & 0x80000000) == 0)
+#define        IN_CLASSA_NET           0xff000000
+#define        IN_CLASSA_NSHIFT        24
+#define        IN_CLASSA_HOST          (0xffffffff & ~IN_CLASSA_NET)
+#define        IN_CLASSA_MAX           128
+
+#define        IN_CLASSB(a)            ((((u32_t)(a)) & 0xc0000000) == 
0x80000000)
+#define        IN_CLASSB_NET           0xffff0000
+#define        IN_CLASSB_NSHIFT        16
+#define        IN_CLASSB_HOST          (0xffffffff & ~IN_CLASSB_NET)
+#define        IN_CLASSB_MAX           65536
+
+#define        IN_CLASSC(a)            ((((u32_t)(a)) & 0xe0000000) == 
0xc0000000)
+#define        IN_CLASSC_NET           0xffffff00
+#define        IN_CLASSC_NSHIFT        8
+#define        IN_CLASSC_HOST          (0xffffffff & ~IN_CLASSC_NET)
+
+#define IN_CLASSD(a)        (((u32_t)(a) & 0xf0000000) == 0xe0000000)
+#define IN_CLASSD_NET       0xf0000000  /* These ones aren't really */
+#define IN_CLASSD_NSHIFT    28      /* net and host fields, but */
+#define IN_CLASSD_HOST      0x0fffffff  /* routing needn't know.    */
+#define IN_MULTICAST(a)     IN_CLASSD(a)
+
+#define IN_EXPERIMENTAL(a)  (((u32_t)(a) & 0xf0000000) == 0xf0000000)
+#define IN_BADCLASS(a)      (((u32_t)(a) & 0xf0000000) == 0xf0000000)
+
+#define IN_LOOPBACKNET      127         /* official! */
+
 #ifdef PACK_STRUCT_USE_INCLUDES
 #  include "arch/bpstruct.h"
 #endif
@@ -50,6 +86,11 @@
 #  include "arch/epstruct.h"
 #endif
 
+/* For compatibility with BSD code */
+struct in_addr {
+         u32_t s_addr;
+};
+
 extern struct ip_addr ip_addr_broadcast;
 
 #define IP4_ADDR(ipaddr, a,b,c,d) (ipaddr)->addr = htonl(((u32_t)(a & 0xff) << 
24) | ((u32_t)(b & 0xff) << 16) | \
diff -ur lwip-cvs-03021900/src/include/lwip/sockets.h 
lwip-cvs-03021900-mb/src/include/lwip/sockets.h
--- lwip-cvs-03021900/src/include/lwip/sockets.h        2003-02-19 
03:28:32.000000000 -0500
+++ lwip-cvs-03021900-mb/src/include/lwip/sockets.h     2003-02-26 
10:25:47.000000000 -0500
@@ -34,11 +34,6 @@
 #ifndef __LWIP_SOCKETS_H__
 #define __LWIP_SOCKETS_H__
 
-struct in_addr {
-  u32_t s_addr;
-};
-
-
 struct sockaddr_in {
   u8_t sin_len;
   u8_t sin_family;