host: add a netmask constructor taking the number of network bits

diff --git a/src/libstrongswan/networking/host.c b/src/libstrongswan/networking/host.c
index c94a1597b9fa60610981241b9b46e23c09337b8f..d275a835e6cd2535228739a83203c9476d3cbcfb 100644 (file)
--- a/src/libstrongswan/networking/host.c
+++ b/src/libstrongswan/networking/host.c
@@ -558,6 +558,55 @@ host_t *host_create_from_subnet(char *string, int *bits)
        return net;
 }
 
+/*
+ * See header.
+ */
+host_t *host_create_netmask(int family, int netbits)
+{
+       private_host_t *this;
+       int bits, bytes, len = 0;
+       char *target;
+
+       switch (family)
+       {
+               case AF_INET:
+                       if (netbits < 0 || netbits > 32)
+                       {
+                               return NULL;
+                       }
+                       this = host_create_empty();
+                       this->socklen = sizeof(struct sockaddr_in);
+                       target = (char*)&this->address4.sin_addr;
+                       len = 4;
+                       break;
+               case AF_INET6:
+                       if (netbits < 0 || netbits > 128)
+                       {
+                               return NULL;
+                       }
+                       this = host_create_empty();
+                       this->socklen = sizeof(struct sockaddr_in6);
+                       target = (char*)&this->address6.sin6_addr;
+                       len = 16;
+                       break;
+               default:
+                       return NULL;
+       }
+
+       memset(&this->address_max, 0, sizeof(struct sockaddr_storage));
+       this->address.sa_family = family;
+       update_sa_len(this);
+
+       bytes = (netbits + 7) / 8;
+       bits = (bytes * 8) - netbits;
+
+       memset(target, 0xff, bytes);
+       memset(target + bytes, 0x00, len - bytes);
+       target[bytes - 1] = bits ? (u_int8_t)(0xff << bits) : 0xff;
+
+       return &this->public;
+}
+
 /*
  * Described in header.
  */

diff --git a/src/libstrongswan/networking/host.h b/src/libstrongswan/networking/host.h
index b36a131d1f640c69e1e4963818dafeafb83ceaca..ae25076ed4841ad76388a21c5d21749f57e923a7 100644 (file)
--- a/src/libstrongswan/networking/host.h
+++ b/src/libstrongswan/networking/host.h
@@ -191,6 +191,14 @@ host_t *host_create_from_sockaddr(sockaddr_t *sockaddr);
  */
 host_t *host_create_from_subnet(char *string, int *bits);
 
+/**
+ * Create a netmask host having the first netbits bits set.
+ *
+ * @param netbits              number of leading bits set in the host
+ * @return                             netmask host
+ */
+host_t *host_create_netmask(int family, int netbits);
+
 /**
  * Create a host without an address, a "any" host.
  *