- fixed bad bugs in kernel interface
[strongswan.git] / Source / charon / threads / kernel_interface.c
index ffc8390..679cf69 100644 (file)
@@ -8,6 +8,9 @@
 /*
  * Copyright (C) 2005 Jan Hutter, Martin Willi
  * Hochschule fuer Technik Rapperswil
+ * Copyright (C) 2003 Herbert Xu.
+ * 
+ * Contains modified parts from pluto.
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License as published by the
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <linux/netlink.h>
-#include <linux/xfrm.h>
 #include <pthread.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <string.h>
 
 #include "kernel_interface.h"
 
-#include <utils/allocator.h>
+#include <daemon.h>
 #include <utils/linked_list.h>
-#include <network/host.h>
-#include <encoding/payloads/proposal_substructure.h>
+
+
+#define KERNEL_ESP 50
+#define KERNEL_AH 51
+
+#define SPD_PRIORITY 1024
+
+#define XFRM_DATA_LENGTH 512
+
+
+typedef struct xfrm_data_t xfrm_data_t;
+
+/**
+ * Lenght/Type/data struct for userdata in xfrm
+ * We dont use the "I-don't-know-where-they-come-from"-structs
+ * used in the kernel.
+ */
+struct xfrm_data_t {
+       /**
+        * length of the data
+        */
+       u_int16_t length;
+       
+       /**
+        * type of data 
+        */
+       u_int16_t type;
+       
+       /**
+        * and the data itself, for different purposes
+        */
+       union {
+               /** algorithm */
+               struct xfrm_algo algo;
+               /** policy tmpl */
+               struct xfrm_user_tmpl tmpl[2];
+       };
+};
 
 
 typedef struct netlink_message_t netlink_message_t;
 
+/**
+ * Representation of ANY netlink message used
+ */
 struct netlink_message_t {
        
        /**
@@ -44,236 +89,641 @@ struct netlink_message_t {
        struct nlmsghdr hdr;
 
        union {
+               /** error message */
                struct nlmsgerr e;
-               struct xfrm_userspi_info spi;                       
+               /** message for spi allocation */
+               struct xfrm_userspi_info spi;
+               /** message for SA manipulation */
+               struct xfrm_usersa_id sa_id;
+               /** message for SA installation */
                struct xfrm_usersa_info sa;
+               /** message for policy manipulation */
+               struct xfrm_userpolicy_id policy_id;
+               /** message for policy installation */
+               struct xfrm_userpolicy_info policy;
        };
-       
-       u_int8_t data[];
+       u_int8_t data[XFRM_DATA_LENGTH];
 };
 
 
 typedef struct private_kernel_interface_t private_kernel_interface_t;
 
  /**
- * @brief Private Variables and Functions of kernel_interface class
+ * @brief Private Variables and Functions of kernel_interface class.
  *
  */
 struct private_kernel_interface_t {
        /**
-        * Public part of the kernel_interface_t object
+        * Public part of the kernel_interface_t object.
+        */
+       kernel_interface_t public;
+       
+       /**
+        * Netlink communication socket.
+        */
+       int socket;
+       
+       /**
+        * Process id of kernel thread
+        */
+       pid_t pid;
+       
+       /**
+        * Sequence number for messages.
         */
-       kernel_interface_t public;
-       
-       /**
-        * netlink communication socket
-        */
-       int socket;
-       
-       /**
-        * since we use multiple threads, we can't call
-        * getpid multiple times. The pid is set once.
-        */
-       pid_t pid;
-       
-       /**
-        * sequence number for messages
-        */
-       u_int32_t seq;
-       
-       /** 
-        * list of replies messages
-        */
-       linked_list_t *replies;
-       
-       /**
-        * Function for the thread, receives messages
-        */
-       void (*receive_messages) (private_kernel_interface_t *this);
-       
-       /**
-        * Sends a netlink_message_t down to the kernel
-        */
-       void (*send_message) (private_kernel_interface_t *this, netlink_message_t *request, netlink_message_t *response);
+       u_int32_t seq;
+       
+       /** 
+        * List of responded messages.
+        */
+       linked_list_t *responses;
+       
+       /**
+        * Thread which receives messages.
+        */
+       pthread_t thread;
+       
+       /**
+        * Mutex locks access to replies list.
+        */
+       pthread_mutex_t mutex;
+       
+       /**
+        * Condvar allows signaling of threads waiting for a reply.
+        */
+       pthread_cond_t condvar;
+       
+       /**
+        * Logger for XFRM stuff
+        */
+       logger_t *logger;
+       
+       /**
+        * Function for the thread, receives messages.
+        */
+       void (*receive_messages) (private_kernel_interface_t *this);
+       
+       /**
+        * Sends a netlink_message_t down to the kernel and wait for reply.
+        */
+       status_t (*send_message) (private_kernel_interface_t *this, netlink_message_t *request, netlink_message_t **response);
 };
 
+/**
+ * In the kernel, algorithms are identified as strings, we use our
+ * mapping functions...
+ * Algorithms for encryption.
+ * TODO: Add missing algorithm strings
+ */
+mapping_t kernel_encryption_algs_m[] = {
+       {ENCR_DES_IV64, ""},
+       {ENCR_DES, "des"},
+       {ENCR_3DES, "des3_ede"},
+       {ENCR_RC5, ""},
+       {ENCR_IDEA, "idea"},
+       {ENCR_CAST, "cast128"},
+       {ENCR_BLOWFISH, "blowfish"},
+       {ENCR_3IDEA, ""},
+       {ENCR_DES_IV32, ""},
+       {ENCR_NULL, ""},
+       {ENCR_AES_CBC, "aes"},
+       {ENCR_AES_CTR, ""},
+       {MAPPING_END, NULL}
+};
+/**
+ * In the kernel, algorithms are identified as strings, we use our
+ * mapping functions...
+ * Algorithms for integrity protection.
+ * TODO: Add missing algorithm strings
+ */
+mapping_t kernel_integrity_algs_m[] = {
+       {AUTH_HMAC_MD5_96, "md5"},
+       {AUTH_HMAC_SHA1_96, "sha1"},
+       {AUTH_DES_MAC, ""},
+       {AUTH_KPDK_MD5, ""},
+       {AUTH_AES_XCBC_96, ""},
+       {MAPPING_END, NULL}
+};
 
-//static u_int32_t get_spi(private_kernel_interface_t *this, host_t *src, host_t *dest, protocol_id_t protocol, bool tunnel_mode)
-//{
-//     netlink_message_t request, response;
-//     
-//    memset(&request, 0, sizeof(request));
-//    request.hdr.nlmsg_flags = NLM_F_REQUEST;
-//    request.hdr.nlmsg_type = XFRM_MSG_ALLOCSPI;
-//     request.spi.info.saddr = src->get_xfrm_addr(src);
-//     request.spi.info.id.daddr = dest->get_xfrm_addr(dest);
-//    request.spi.info.mode = tunnel_mode;
-//    request.spi.info.id.proto = protocol;
-//    request.spi.info.family = src->get_family(src);
-//    request.spi.min = 0;
-//    request.spi.max = 50000;
-//    request.hdr.nlmsg_len = NLMSG_ALIGN(NLMSG_LENGTH(sizeof(request.spi)));
-//
-//    this->send_message(this, &request, &response);
-//
-//    if (response.hdr.nlmsg_type == NLMSG_ERROR)
-//    {
-//             /* error handling */
-//    }
-//    else if (response.hdr.nlmsg_len < NLMSG_LENGTH(sizeof(response.sa)))
-//    {
-//             /* error handling */
-//    }
-//
-//    return response.sa.id.spi;
-//}
-//
-//
-//
-//static status_t send_message(private_kernel_interface_t *this, netlink_message_t *request, netlink_message_t *response)
-//{
-//     size_t length;
-//     ssize_t r;
-//     
-//     length = request->hdr.nlmsg_len;
-//     
-//     
-//     
-//
-//
-//    size_t len;
-//    ssize_t r;
-//
-//
-//
-//    request->hdr.nlmsg_seq = ++this->seq;
-//     length = request->hdr.nlmsg_len;
-//     
-//    do {
-//             r = write(netlinkfd, hdr, len);
-//    } while (r < 0 && errno == EINTR);
-//    
-//    if (r < 0)
-//    {
-//             return FAILED;
-//    }
-//    else if ((size_t)r != len)
-//    {
-//             return FAILED;
-//    }
-//    
-//    
-//    /* wait for receiver thread */
-//
-//    return TRUE;
-//}
-//
-//
-//static void receive_messages(private_kernel_interface_t *this)
-//{
-//     while(TRUE) 
-//     {
-//             netlink_message_t *response;
-//             
-//             
-//             socklen_t addr_length;
-//     struct sockaddr_nl addr;
-//             size_t length;
-//
-//             addr_length = sizeof(addr);
-//             length = recvfrom(netlinkfd, &rsp, sizeof(rsp), 0, (struct sockaddr*)&addr, &addr_length);
-//             if (r < 0)
-//             {
-//                     if (errno == EINTR)
-//             {
-//                             continue;
-//             }
-//             return FAILED;
-//             }
-//             else if ((size_t) r < sizeof(rsp.n))
-//             {
-//                     /* not enought bytes for header */
-//                     continue;
-//             }
-//             else if (addr.nl_pid != 0)
-//             {
-//                     /* not interested */
-//                 continue;
-//             }
-//             else if (rsp.n.nlmsg_seq != seq)
-//             {
-//                 DBG(DBG_KLIPS,
-//                     DBG_log("netlink: ignoring out of sequence (%u/%u) message %s"
-//                         , rsp.n.nlmsg_seq, seq
-//                         , sparse_val_show(xfrm_type_names, rsp.n.nlmsg_type)));
-//                 continue;
-//             }
-//             break;
-//    }
-//
-//    if (rsp.n.nlmsg_len > (size_t) r)
-//    {
-//             return FALSE;
-//    }
-//    else if (rsp.n.nlmsg_type != NLMSG_ERROR
-//    && (rbuf && rsp.n.nlmsg_type != rbuf->nlmsg_type))
-//    {
-//     loglog(RC_LOG_SERIOUS
-//         , "netlink recvfrom() of response to our %s message"
-//           " for %s %s was of wrong type (%s)"
-//         , sparse_val_show(xfrm_type_names, hdr->nlmsg_type)
-//         , description, text_said
-//         , sparse_val_show(xfrm_type_names, rsp.n.nlmsg_type));
-//     return FALSE;
-//    }
-//    else if (rbuf)
-//    {
-//     if ((size_t) r > rbuf_len)
-//     {
-//         loglog(RC_LOG_SERIOUS
-//             , "netlink recvfrom() of response to our %s message"
-//               " for %s %s was too long: %ld > %lu"
-//             , sparse_val_show(xfrm_type_names, hdr->nlmsg_type)
-//             , description, text_said
-//             , (long)r, (unsigned long)rbuf_len);
-//         return FALSE;
-//     }
-//     memcpy(rbuf, &rsp, r);
-//     return TRUE;
-//    }
-//    else if (rsp.n.nlmsg_type == NLMSG_ERROR && rsp.e.error)
-//    {
-//     loglog(RC_LOG_SERIOUS
-//         , "ERROR: netlink response for %s %s included errno %d: %s"
-//         , description, text_said
-//         , -rsp.e.error
-//         , strerror(-rsp.e.error));
-//     return FALSE;
-//    }        
-//}
 
+/**
+ * Implementation of kernel_interface_t.get_spi.
+ */
+static status_t get_spi(private_kernel_interface_t *this, 
+                                               host_t *src, host_t *dest, 
+                                               protocol_id_t protocol, u_int32_t reqid,
+                                               u_int32_t *spi)
+{
+       netlink_message_t request, *response;
+       status_t status = SUCCESS;
+       
+       
+       this->logger->log(this->logger, CONTROL|LEVEL2, "getting spi");
+       
+       memset(&request, 0, sizeof(request));
+       request.hdr.nlmsg_len = NLMSG_ALIGN(NLMSG_LENGTH(sizeof(request.spi)));
+       request.hdr.nlmsg_flags = NLM_F_REQUEST;
+       request.hdr.nlmsg_type = XFRM_MSG_ALLOCSPI;
+       request.spi.info.saddr = src->get_xfrm_addr(src);
+       request.spi.info.id.daddr = dest->get_xfrm_addr(dest);
+       request.spi.info.mode = TRUE; /* tunnel mode */
+       request.spi.info.reqid = reqid;
+       request.spi.info.id.proto = (protocol == PROTO_ESP) ? KERNEL_ESP : KERNEL_AH;
+       request.spi.info.family = PF_INET;
+       request.spi.min = 0xc0000000;
+       request.spi.max = 0xcFFFFFFF;
+       
+       if (this->send_message(this, &request, &response) != SUCCESS)
+       {
+               this->logger->log(this->logger, ERROR, "netlink communication failed");
+               return FAILED;
+       }
+       else if (response->hdr.nlmsg_type == NLMSG_ERROR)
+       {
+               this->logger->log(this->logger, ERROR, "netlink request XFRM_MSG_ALLOCSPI got an error: %s",
+                                                 strerror(-response->e.error));
+               status = FAILED;
+       }
+       else if (response->hdr.nlmsg_type != XFRM_MSG_NEWSA)
+       {
+               this->logger->log(this->logger, ERROR, "netlink request XFRM_MSG_ALLOCSPI got a unknown reply");
+               status = FAILED;
+       }
+       else if (response->hdr.nlmsg_len < NLMSG_LENGTH(sizeof(response->sa)))
+       {
+               this->logger->log(this->logger, ERROR, "netlink request XFRM_MSG_ALLOCSPI got an invalid reply");
+               status = FAILED;
+       }
+       else
+       {
+               *spi = response->sa.id.spi;
+       }
+       free(response);
+       
+       return status;
+}
 
+/**
+ * Implementation of kernel_interface_t.add_sa.
+ */
+static status_t add_sa(        private_kernel_interface_t *this,
+                                               host_t *me,
+                                               host_t *other,
+                                               u_int32_t spi,
+                                               int protocol,
+                                               u_int32_t reqid,
+                                               encryption_algorithm_t enc_alg,
+                                               chunk_t encryption_key,
+                                               integrity_algorithm_t int_alg,
+                                               chunk_t integrity_key,
+                                               bool replace)
+{
+       netlink_message_t request, *response;
+       memset(&request, 0, sizeof(request));
+       status_t status = SUCCESS;
+       
+       this->logger->log(this->logger, CONTROL|LEVEL2, "adding SA");
+       
+       request.hdr.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
+       request.hdr.nlmsg_type = replace ? XFRM_MSG_UPDSA : XFRM_MSG_NEWSA;
+       
+       request.sa.saddr = me->get_xfrm_addr(me);
+       request.sa.id.daddr = other->get_xfrm_addr(other);
+       
+       request.sa.id.spi = spi;
+       request.sa.id.proto = (protocol == PROTO_ESP) ? KERNEL_ESP : KERNEL_AH;
+       request.sa.family = me->get_family(me);
+       request.sa.mode = TRUE; /* tunnel mode */
+       request.sa.replay_window = 32;
+       request.sa.reqid = reqid;
+       request.sa.lft.soft_byte_limit = XFRM_INF;
+       request.sa.lft.soft_packet_limit = XFRM_INF;
+       request.sa.lft.hard_byte_limit = XFRM_INF;
+       request.sa.lft.hard_packet_limit = XFRM_INF;
+       
+       request.hdr.nlmsg_len = NLMSG_ALIGN(NLMSG_LENGTH(sizeof(request.sa)));
+       
+       if (enc_alg != ENCR_UNDEFINED)
+       {
+               xfrm_data_t *data = (xfrm_data_t*)(((u_int8_t*)&request) + request.hdr.nlmsg_len);
+               
+               data->type = XFRMA_ALG_CRYPT;
+               data->length = 4 + sizeof(data->algo) + encryption_key.len;
+               data->algo.alg_key_len = encryption_key.len * 8;
+               request.hdr.nlmsg_len += data->length;
+               if (request.hdr.nlmsg_len > sizeof(request))
+               {
+                       return FAILED;
+               }
+               strcpy(data->algo.alg_name, mapping_find(kernel_encryption_algs_m, enc_alg));
+               memcpy(data->algo.alg_key, encryption_key.ptr, encryption_key.len);
+       }
+       
+       if (int_alg != AUTH_UNDEFINED)
+       {
+               xfrm_data_t *data = (xfrm_data_t*)(((u_int8_t*)&request) + request.hdr.nlmsg_len);
+               
+               data->type = XFRMA_ALG_AUTH;
+               data->length = 4 + sizeof(data->algo) + integrity_key.len;
+               data->algo.alg_key_len = integrity_key.len * 8;
+               request.hdr.nlmsg_len += data->length;
+               if (request.hdr.nlmsg_len > sizeof(request))
+               {
+                       return FAILED;
+               }
+               strcpy(data->algo.alg_name, mapping_find(kernel_integrity_algs_m, int_alg));
+               memcpy(data->algo.alg_key, integrity_key.ptr, integrity_key.len);
+       }
+       
+       /* TODO: add IPComp here*/
+       
+       if (this->send_message(this, &request, &response) != SUCCESS)
+       {
+               this->logger->log(this->logger, ERROR, "netlink communication failed");
+               return FAILED;
+       }
+       else if (response->hdr.nlmsg_type != NLMSG_ERROR)
+       {
+               this->logger->log(this->logger, ERROR, "netlink request XFRM_MSG_NEWSA not acknowledged");
+               status = FAILED;
+       }
+       else if (response->e.error)
+       {
+               this->logger->log(this->logger, ERROR, "netlink request XFRM_MSG_NEWSA got error %s",
+                                                 strerror(-response->e.error));
+               status = FAILED;
+       }
+       
+       free(response);
+       return status;
+}
 
- /**
- * implements kernel_interface_t.destroy
+static status_t del_sa(        private_kernel_interface_t *this,
+                                               host_t *dst,
+                                               u_int32_t spi,
+                                               protocol_id_t protocol)
+{
+       netlink_message_t request, *response;
+       memset(&request, 0, sizeof(request));
+       status_t status = SUCCESS;
+       
+       this->logger->log(this->logger, CONTROL|LEVEL2, "deleting SA");
+       
+       request.hdr.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
+       request.hdr.nlmsg_type = XFRM_MSG_DELSA;
+       
+       request.sa_id.daddr = dst->get_xfrm_addr(dst);
+       
+       request.sa_id.spi = spi;
+       request.sa_id.proto = (protocol == PROTO_ESP) ? KERNEL_ESP : KERNEL_AH;
+       request.sa_id.family = dst->get_family(dst);
+       
+       request.hdr.nlmsg_len = NLMSG_ALIGN(NLMSG_LENGTH(sizeof(request.sa_id)));
+       
+       if (this->send_message(this, &request, &response) != SUCCESS)
+       {
+               return FAILED;
+       }
+       else if (response->hdr.nlmsg_type != NLMSG_ERROR)
+       {
+               status = FAILED;
+       }
+       else if (response->e.error)
+       {
+               status = FAILED;
+       }
+       
+       free(response);
+       return status;
+}
+
+/**
+ * Implementation of kernel_interface_t.add_policy.
+ */
+static status_t add_policy(private_kernel_interface_t *this, 
+                                                 host_t *me, host_t *other, 
+                                                 host_t *src, host_t *dst,
+                                                 u_int8_t src_hostbits, u_int8_t dst_hostbits,
+                                                 int direction, int upper_proto, 
+                                                 bool ah, bool esp,
+                                                 u_int32_t reqid)
+{
+       netlink_message_t request, *response;
+       status_t status = SUCCESS;
+       
+       this->logger->log(this->logger, CONTROL|LEVEL2, "adding policy");
+       
+       memset(&request, 0, sizeof(request));
+       request.hdr.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
+
+       request.policy.sel.sport = htons(src->get_port(src));
+       request.policy.sel.dport = htons(dst->get_port(dst));
+       request.policy.sel.sport_mask = (request.policy.sel.sport) ? ~0 : 0;
+       request.policy.sel.dport_mask = (request.policy.sel.dport) ? ~0 : 0;
+       request.policy.sel.saddr = src->get_xfrm_addr(src);
+       request.policy.sel.daddr = dst->get_xfrm_addr(dst);
+       request.policy.sel.prefixlen_s = src_hostbits;
+       request.policy.sel.prefixlen_d = dst_hostbits;
+       request.policy.sel.proto = upper_proto;
+       request.policy.sel.family = src->get_family(src);
+
+       request.hdr.nlmsg_type = XFRM_MSG_NEWPOLICY;
+       request.hdr.nlmsg_len = NLMSG_ALIGN(NLMSG_LENGTH(sizeof(request.policy)));
+
+       request.policy.dir = direction;
+       request.policy.priority = SPD_PRIORITY;
+       request.policy.action = XFRM_POLICY_ALLOW;
+       request.policy.share = XFRM_SHARE_ANY;
+       
+       request.policy.lft.soft_byte_limit = XFRM_INF;
+       request.policy.lft.soft_packet_limit = XFRM_INF;
+       request.policy.lft.hard_byte_limit = XFRM_INF;
+       request.policy.lft.hard_packet_limit = XFRM_INF;
+       
+       if (esp || ah)
+       {
+               xfrm_data_t *data;
+               int tmpl_pos = 0;
+               data = (xfrm_data_t*)(((u_int8_t*)&request) + request.hdr.nlmsg_len);
+               data->type = XFRMA_TMPL;
+               if (esp)
+               {
+                       data->tmpl[tmpl_pos].reqid = reqid;
+                       data->tmpl[tmpl_pos].id.proto = KERNEL_ESP;
+                       data->tmpl[tmpl_pos].aalgos = data->tmpl[tmpl_pos].ealgos = data->tmpl[tmpl_pos].calgos = ~0;
+                       data->tmpl[tmpl_pos].mode = TRUE;
+                       
+                       data->tmpl[tmpl_pos].saddr = me->get_xfrm_addr(me);
+                       data->tmpl[tmpl_pos].id.daddr = me->get_xfrm_addr(other);
+                       
+                       tmpl_pos++;
+               }       
+               if (ah)
+               {
+                       data->tmpl[tmpl_pos].reqid = reqid;
+                       data->tmpl[tmpl_pos].id.proto = KERNEL_AH;
+                       data->tmpl[tmpl_pos].aalgos = data->tmpl[tmpl_pos].ealgos = data->tmpl[tmpl_pos].calgos = ~0;
+                       data->tmpl[tmpl_pos].mode = TRUE;
+                       
+                       data->tmpl[tmpl_pos].saddr = me->get_xfrm_addr(me);
+                       data->tmpl[tmpl_pos].id.daddr = other->get_xfrm_addr(other);
+                       
+                       tmpl_pos++;
+               }
+               data->length = 4 + sizeof(struct xfrm_user_tmpl) * tmpl_pos;
+               request.hdr.nlmsg_len += data->length;
+       }
+       
+       if (this->send_message(this, &request, &response) != SUCCESS)
+       {
+               this->logger->log(this->logger, ERROR, "netlink communication failed");
+               return FAILED;
+       }
+       else if (response->hdr.nlmsg_type != NLMSG_ERROR)
+       {
+               this->logger->log(this->logger, ERROR, "netlink request XFRM_MSG_NEWPOLICY not acknowledged");
+               status = FAILED;
+       }
+       else if (response->e.error)
+       {
+               this->logger->log(this->logger, ERROR, "netlink request XFRM_MSG_NEWPOLICY got error %s",
+                                                 strerror(-response->e.error));
+               status = FAILED;
+       }
+       
+       free(response);
+       return status;
+}
+
+/**
+ * Implementation of kernel_interface_t.del_policy.
+ */
+static status_t del_policy(private_kernel_interface_t *this, 
+                                                  host_t *me, host_t *other, 
+                                                  host_t *src, host_t *dst,
+                                                  u_int8_t src_hostbits, u_int8_t dst_hostbits,
+                                                  int direction, int upper_proto)
+{
+       netlink_message_t request, *response;
+       status_t status = SUCCESS;
+       
+       
+       this->logger->log(this->logger, CONTROL|LEVEL2, "deleting policy");
+       
+       memset(&request, 0, sizeof(request));
+       request.hdr.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
+
+       request.policy_id.sel.sport = htons(src->get_port(src));
+       request.policy_id.sel.dport = htons(dst->get_port(dst));
+       request.policy_id.sel.sport_mask = (request.policy.sel.sport) ? ~0 : 0;
+       request.policy_id.sel.dport_mask = (request.policy.sel.dport) ? ~0 : 0;
+       request.policy_id.sel.saddr = src->get_xfrm_addr(src);
+       request.policy_id.sel.daddr = dst->get_xfrm_addr(dst);
+       request.policy_id.sel.prefixlen_s = src_hostbits;
+       request.policy_id.sel.prefixlen_d = dst_hostbits;
+       request.policy_id.sel.proto = upper_proto;
+       request.policy_id.sel.family = src->get_family(src);
+       
+       request.policy_id.dir = direction;
+
+       request.hdr.nlmsg_type = XFRM_MSG_DELPOLICY;
+       request.hdr.nlmsg_len = NLMSG_ALIGN(NLMSG_LENGTH(sizeof(request.policy_id)));
+       
+       if (this->send_message(this, &request, &response) != SUCCESS)
+       {
+               return FAILED;
+       }
+       else if (response->hdr.nlmsg_type != NLMSG_ERROR)
+       {
+               status = FAILED;
+       }
+       else if (response->e.error)
+       {
+               status = FAILED;
+       }
+       
+       free(response);
+       return status;
+}
+
+/**
+ * Implementation of private_kernel_interface_t.send_message.
  */
-static void destroy (private_kernel_interface_t *this)
+static status_t send_message(private_kernel_interface_t *this, netlink_message_t *request, netlink_message_t **response)
+{
+       size_t length;
+       struct sockaddr_nl addr;
+       
+       request->hdr.nlmsg_seq = ++this->seq;
+       request->hdr.nlmsg_pid = this->pid;
+       
+       memset(&addr, 0, sizeof(struct sockaddr_nl));
+       addr.nl_family = AF_NETLINK;
+       addr.nl_pid = 0;
+       addr.nl_groups = 0;
+       
+       length = sendto(this->socket,(void *)request, request->hdr.nlmsg_len, 0, (struct sockaddr *)&addr, sizeof(addr));
+       
+       if (length < 0)
+       {
+               return FAILED;
+       }
+       else if (length != request->hdr.nlmsg_len)
+       {
+               return FAILED;
+       }
+       
+       pthread_mutex_lock(&(this->mutex));
+       
+       while (TRUE)
+       {
+               iterator_t *iterator; 
+               bool found = FALSE;
+               /* search list, break if found */
+               iterator = this->responses->create_iterator(this->responses, TRUE);
+               while (iterator->has_next(iterator))
+               {
+                       netlink_message_t *listed_response;
+                       iterator->current(iterator, (void**)&listed_response);
+                       if (listed_response->hdr.nlmsg_seq == request->hdr.nlmsg_seq)
+                       {
+                               /* matches our request, this is the reply */
+                               *response = listed_response;
+                               found = TRUE;
+                               break;
+                       }
+               }
+               iterator->destroy(iterator);
+               
+               if (found)
+               {
+                       break;
+               }
+               /* TODO: we should time out, if something goes wrong!??? */
+               pthread_cond_wait(&(this->condvar), &(this->mutex));
+       }
+       
+       pthread_mutex_unlock(&(this->mutex));
+       
+       return SUCCESS;
+}
+
+/**
+ * Implementation of private_kernel_interface_t.receive_messages.
+ */
+static void receive_messages(private_kernel_interface_t *this)
+{
+       while(TRUE) 
+       {
+               netlink_message_t response, *listed_response;
+               while (TRUE)
+               {
+                       struct sockaddr_nl addr;
+                       socklen_t addr_length;
+                       size_t length;
+                       
+                       addr_length = sizeof(addr);
+                       
+                       response.hdr.nlmsg_type = XFRM_MSG_NEWSA;
+                       length = recvfrom(this->socket, &response, sizeof(response), 0, (struct sockaddr*)&addr, &addr_length);
+                       if (length < 0)
+                       {
+                               if (errno == EINTR)
+                               {
+                                       /* interrupted, try again */
+                                       continue;
+                               }
+                               charon->kill(charon, "receiving from netlink socket failed");
+                       }
+                       if (!NLMSG_OK(&response.hdr, length))
+                       {
+                               /* bad netlink message */
+                               continue;
+                       }
+                       if (addr.nl_pid != 0)
+                       {
+                               /* not from kernel. not interested, try another one */
+                               continue;
+                       }
+                       break;
+               }
+               
+               /* got a valid message.
+                * requests are handled on our own, 
+                * responses are listed for the requesters
+                */
+               if (response.hdr.nlmsg_flags & NLM_F_REQUEST)
+               {
+                       /* handle request */    
+               }
+               else
+               {
+                       /* add response to queue */                     
+                       listed_response = malloc(sizeof(response));
+                       memcpy(listed_response, &response, sizeof(response));
+
+                       pthread_mutex_lock(&(this->mutex));
+                       this->responses->insert_last(this->responses, (void*)listed_response);
+                       pthread_mutex_unlock(&(this->mutex));
+                       /* signal ALL waiting threads */
+                       pthread_cond_broadcast(&(this->condvar));
+               }
+               /* get the next one */
+       }
+}
+
+/**
+ * Implementation of kernel_interface_t.destroy.
+ */
+static void destroy(private_kernel_interface_t *this)
 {      
-       allocator_free(this);
+       pthread_cancel(this->thread);
+       pthread_join(this->thread, NULL);
+       close(this->socket);
+       this->responses->destroy(this->responses);
+       free(this);
 }
 
 /*
- * Documented in header
+ * Described in header.
  */
 kernel_interface_t *kernel_interface_create()
 {
-       private_kernel_interface_t *this = allocator_alloc_thing(private_kernel_interface_t);
+       private_kernel_interface_t *this = malloc_thing(private_kernel_interface_t);
        
        /* public functions */
+       this->public.get_spi = (status_t(*)(kernel_interface_t*,host_t*,host_t*,protocol_id_t,u_int32_t,u_int32_t*))get_spi;
+       this->public.add_sa  = (status_t(*)(kernel_interface_t *,host_t*,host_t*,u_int32_t,protocol_id_t,u_int32_t,encryption_algorithm_t,chunk_t,integrity_algorithm_t,chunk_t,bool))add_sa;
+       this->public.add_policy = (status_t(*)(kernel_interface_t*,host_t*, host_t*,host_t*,host_t*,u_int8_t,u_int8_t,int,int,bool,bool,u_int32_t))add_policy;
+       this->public.del_sa = (status_t(*)(kernel_interface_t*,host_t*,u_int32_t,protocol_id_t))del_sa;
+       this->public.del_policy = (status_t(*)(kernel_interface_t*,host_t*,host_t*,host_t*,host_t*,u_int8_t,u_int8_t,int,int))del_policy;
+       
        this->public.destroy = (void(*)(kernel_interface_t*)) destroy;
 
        /* private members */
+       this->receive_messages = receive_messages;
+       this->send_message = send_message;
+       this->pid = getpid();
+       this->responses = linked_list_create();
+       this->logger = logger_manager->get_logger(logger_manager, XFRM);
+       pthread_mutex_init(&(this->mutex),NULL);
+       pthread_cond_init(&(this->condvar),NULL);
+       this->seq = 0;
        this->socket = socket(PF_NETLINK, SOCK_RAW, NETLINK_XFRM);
+       if (this->socket <= 0)
+       {
+               this->responses->destroy(this->responses);
+               free(this);
+               charon->kill(charon, "Unable to create netlink socket");        
+       }
+       
+       if (pthread_create(&(this->thread), NULL, (void*(*)(void*))this->receive_messages, this) != 0)
+       {
+               this->responses->destroy(this->responses);
+               close(this->socket);
+               free(this);
+               charon->kill(charon, "Unable to create netlink thread");
+       }
        
        return (&this->public);
 }