add libip
diff --git a/src/libip/parseip.c b/src/libip/parseip.c
new file mode 100644
index 0000000..c0dd55c
--- /dev/null
+++ b/src/libip/parseip.c
@@ -0,0 +1,135 @@
+#include <u.h>
+#include <libc.h>
+#include <ip.h>
+
+char*
+v4parseip(uchar *to, char *from)
+{
+ int i;
+ char *p;
+
+ p = from;
+ for(i = 0; i < 4 && *p; i++){
+ to[i] = strtoul(p, &p, 0);
+ if(*p == '.')
+ p++;
+ }
+ switch(CLASS(to)){
+ case 0: /* class A - 1 uchar net */
+ case 1:
+ if(i == 3){
+ to[3] = to[2];
+ to[2] = to[1];
+ to[1] = 0;
+ } else if (i == 2){
+ to[3] = to[1];
+ to[1] = 0;
+ }
+ break;
+ case 2: /* class B - 2 uchar net */
+ if(i == 3){
+ to[3] = to[2];
+ to[2] = 0;
+ }
+ break;
+ }
+ return p;
+}
+
+ulong
+parseip(uchar *to, char *from)
+{
+ int i, elipsis = 0, v4 = 1;
+ ulong x;
+ char *p, *op;
+
+ memset(to, 0, IPaddrlen);
+ p = from;
+ for(i = 0; i < 16 && *p; i+=2){
+ op = p;
+ x = strtoul(p, &p, 16);
+ if(*p == '.' || (*p == 0 && i == 0)){
+ p = v4parseip(to+i, op);
+ i += 4;
+ break;
+ }
+ to[i] = x>>8;
+ to[i+1] = x;
+ if(*p == ':'){
+ v4 = 0;
+ if(*++p == ':'){
+ elipsis = i+2;
+ p++;
+ }
+ }
+ }
+ if(i < 16){
+ memmove(&to[elipsis+16-i], &to[elipsis], i-elipsis);
+ memset(&to[elipsis], 0, 16-i);
+ }
+ if(v4){
+ to[10] = to[11] = 0xff;
+ return nhgetl(to+12);
+ } else
+ return 6;
+}
+
+/*
+ * hack to allow ip v4 masks to be entered in the old
+ * style
+ */
+ulong
+parseipmask(uchar *to, char *from)
+{
+ ulong x;
+ int i;
+ uchar *p;
+
+ if(*from == '/'){
+ /* as a number of prefix bits */
+ i = atoi(from+1);
+ if(i < 0)
+ i = 0;
+ if(i > 128)
+ i = 128;
+ memset(to, 0, IPaddrlen);
+ for(p = to; i >= 8; i -= 8)
+ *p++ = 0xff;
+ if(i > 0)
+ *p = ~((1<<(8-i))-1);
+ x = nhgetl(to+IPv4off);
+ } else {
+ /* as a straight bit mask */
+ x = parseip(to, from);
+ if(memcmp(to, v4prefix, IPv4off) == 0)
+ memset(to, 0xff, IPv4off);
+ }
+ return x;
+}
+
+/*
+ * parse a v4 ip address/mask in cidr format
+ */
+char*
+v4parsecidr(uchar *addr, uchar *mask, char *from)
+{
+ int i;
+ char *p;
+ uchar *a;
+
+ p = v4parseip(addr, from);
+
+ if(*p == '/'){
+ /* as a number of prefix bits */
+ i = strtoul(p+1, &p, 0);
+ if(i > 32)
+ i = 32;
+ memset(mask, 0, IPv4addrlen);
+ for(a = mask; i >= 8; i -= 8)
+ *a++ = 0xff;
+ if(i > 0)
+ *a = ~((1<<(8-i))-1);
+ } else
+ memcpy(mask, defmask(addr), IPv4addrlen);
+ return p;
+}
