lib/in46a: Introduce in46a_netmasklen API
Change-Id: I06e3e038afd8f7afaec2a3fa67b1616500c8db80
diff --git a/lib/in46_addr.c b/lib/in46_addr.c
index 32e0f8d..36ad6af 100644
--- a/lib/in46_addr.c
+++ b/lib/in46_addr.c
@@ -195,6 +195,64 @@
}
}
+static unsigned int ipv4_netmasklen(const struct in_addr *netmask)
+{
+ uint32_t bits = netmask->s_addr;
+ uint8_t *b = (uint8_t*) &bits;
+ unsigned int i, prefix = 0;
+
+ for (i = 0; i < 4; i++) {
+ while (b[i] & 0x80) {
+ prefix++;
+ b[i] = b[i] << 1;
+ }
+ }
+ return prefix;
+}
+
+static unsigned int ipv6_netmasklen(const struct in6_addr *netmask)
+{
+ #if defined(__linux__)
+ #define ADDRFIELD(i) s6_addr32[i]
+ #else
+ #define ADDRFIELD(i) __u6_addr.__u6_addr32[i]
+ #endif
+
+ unsigned int i, j, prefix = 0;
+
+ for (j = 0; j < 4; j++) {
+ uint32_t bits = netmask->ADDRFIELD(j);
+ uint8_t *b = (uint8_t*) &bits;
+ for (i = 0; i < 4; i++) {
+ while (b[i] & 0x80) {
+ prefix++;
+ b[i] = b[i] << 1;
+ }
+ }
+ }
+
+ #undef ADDRFIELD
+
+ return prefix;
+}
+
+/*! Convert netmask to prefix length representation
+ * \param[in] netmask in46_addr containing a netmask (consecutive list of 1-bit followed by consecutive list of 0-bit)
+ * \returns prefix length representation of the netmask (count of 1-bit from the start of the netmask)
+ */
+unsigned int in46a_netmasklen(const struct in46_addr *netmask)
+{
+ switch (netmask->len) {
+ case 4:
+ return ipv4_netmasklen(&netmask->v4);
+ case 16:
+ return ipv6_netmasklen(&netmask->v6);
+ default:
+ OSMO_ASSERT(0);
+ return 0;
+ }
+}
+
/*! Convert given PDP End User Address to in46_addr
* \returns 0 on success; negative on error */
int in46a_to_eua(const struct in46_addr *src, struct ul66_t *eua)