chiark / gitweb /
Import release 0.1.11
[secnet.git] / site.c
diff --git a/site.c b/site.c
index da410c0c1a1fe6a93b2429337f83cdde6f424e9f..cb0e0aa858813eae3c95e2f415054daa92b36e57 100644 (file)
--- a/site.c
+++ b/site.c
@@ -1,7 +1,17 @@
 /* site.c - manage communication with a remote network site */
 
+/* The 'site' code doesn't know anything about the structure of the
+   packets it's transmitting.  In fact, under the new netlink
+   configuration scheme it doesn't need to know anything at all about
+   IP addresses, except how to contact its peer.  This means it could
+   potentially be used to tunnel other protocols too (IPv6, IPX, plain
+   old Ethernet frames) if appropriate netlink code can be written
+   (and that ought not to be too hard, eg. using the TUN/TAP device to
+   pretend to be an Ethernet interface).  */
+
 #include "secnet.h"
 #include <stdio.h>
+#include <string.h>
 /* MBM asserts the next one is needed for compilation under BSD. */
 #include <sys/socket.h>
 
@@ -119,12 +129,6 @@ static struct flagstr log_event_table[]={
     { NULL, 0 }
 };
 
-static struct flagstr netlink_option_table[]={
-    { "soft", NETLINK_OPTION_SOFTROUTE },
-    { "allow-route", NETLINK_OPTION_ALLOW_ROUTE },
-    { NULL, 0}
-};
-
 struct site {
     closure_t cl;
     struct site_if ops;
@@ -140,7 +144,6 @@ struct site {
     struct log_if *log;
     struct random_if *random;
     struct rsaprivkey_if *privkey;
-    struct subnet_list remotenets;
     struct rsapubkey_if *pubkey;
     struct transform_if *transform;
     struct dh_if *dh;
@@ -167,8 +170,6 @@ struct site {
     uint32_t state;
     uint64_t now; /* Most recently seen time */
 
-    void *netlink_cid;
-
     uint32_t remote_session_id;
     struct transform_inst_if *current_transform;
     bool_t current_valid;
@@ -209,8 +210,8 @@ static void slog(struct site *st, uint32_t event, string_t msg, ...)
        case LOG_STATE: class=M_DEBUG; break;
        case LOG_DROP: class=M_DEBUG; break;
        case LOG_DUMP: class=M_DEBUG; break;
-       case LOG_ERROR: class=M_ERROR; break;
-       default: class=M_ERROR; break;
+       case LOG_ERROR: class=M_ERR; break;
+       default: class=M_ERR; break;
        }
 
        vsnprintf(buf,240,msg,ap);
@@ -220,7 +221,8 @@ static void slog(struct site *st, uint32_t event, string_t msg, ...)
 }
 
 static void set_link_quality(struct site *st);
-static bool_t initiate_key_setup(struct site *st);
+static void delete_key(struct site *st, string_t reason, uint32_t loglevel);
+static bool_t initiate_key_setup(struct site *st, string_t reason);
 static void enter_state_run(struct site *st);
 static bool_t enter_state_resolve(struct site *st);
 static bool_t enter_state_sentmsg1(struct site *st);
@@ -515,6 +517,9 @@ static bool_t generate_msg5(struct site *st)
     /* We are going to add three words to the transformed message */
     buffer_init(&st->buffer,st->transform->max_start_pad+(4*3));
     buf_append_uint32(&st->buffer,LABEL_MSG5);
+    /* Give the netlink code an opportunity to put its own stuff in the
+       message (configuration information, etc.) */
+    st->netlink->output_config(st->netlink->st,&st->buffer);
     st->new_transform->forwards(st->new_transform->st,&st->buffer,
                                &transform_err);
     buf_prepend_uint32(&st->buffer,LABEL_MSG5);
@@ -564,6 +569,10 @@ static bool_t process_msg5(struct site *st, struct buffer_if *msg5,
        slog(st,LOG_SEC,"MSG5/PING packet contained invalid data");
        return False;
     }
+    if (!st->netlink->check_config(st->netlink->st,msg5)) {
+       slog(st,LOG_SEC,"MSG5/PING packet contained bad netlink config");
+       return False;
+    }
     CHECK_EMPTY(msg5);
     return True;
 }
@@ -576,6 +585,9 @@ static bool_t generate_msg6(struct site *st)
     /* We are going to add three words to the transformed message */
     buffer_init(&st->buffer,st->transform->max_start_pad+(4*3));
     buf_append_uint32(&st->buffer,LABEL_MSG6);
+    /* Give the netlink code an opportunity to put its own stuff in the
+       message (configuration information, etc.) */
+    st->netlink->output_config(st->netlink->st,&st->buffer);
     st->new_transform->forwards(st->new_transform->st,&st->buffer,
                                &transform_err);
     buf_prepend_uint32(&st->buffer,LABEL_MSG6);
@@ -606,6 +618,10 @@ static bool_t process_msg6(struct site *st, struct buffer_if *msg6,
        slog(st,LOG_SEC,"MSG6/PONG packet contained invalid data");
        return False;
     }
+    if (!st->netlink->check_config(st->netlink->st,msg6)) {
+       slog(st,LOG_SEC,"MSG6/PONG packet contained bad netlink config");
+       return False;
+    }
     CHECK_EMPTY(msg6);
     return True;
 }
@@ -619,7 +635,7 @@ static bool_t process_msg0(struct site *st, struct buffer_if *msg0,
 
     if (!st->current_valid) {
        slog(st,LOG_DROP,"incoming message but no current key -> dropping");
-       return initiate_key_setup(st);
+       return initiate_key_setup(st,"incoming message but no current key");
     }
 
     if (!unpick_msg0(st,msg0,&m)) return False;
@@ -628,14 +644,19 @@ static bool_t process_msg0(struct site *st, struct buffer_if *msg0,
                                       msg0,&transform_err)) {
        /* There's a problem */
        slog(st,LOG_SEC,"transform: %s",transform_err);
-       return False;
+       return initiate_key_setup(st,"incoming message would not decrypt");
     }
     CHECK_AVAIL(msg0,4);
     type=buf_unprepend_uint32(msg0);
     switch(type) {
+    case LABEL_MSG7:
+       /* We must forget about the current session. */
+       delete_key(st,"request from peer",LOG_SEC);
+       return True;
+       break;
     case LABEL_MSG9:
        /* Deliver to netlink layer */
-       st->netlink->deliver(st->netlink->st,st->netlink_cid,msg0);
+       st->netlink->deliver(st->netlink->st,msg0);
        return True;
        break;
     default:
@@ -700,15 +721,15 @@ static void site_resolve_callback(void *sst, struct in_addr *address)
     }
 }
 
-static bool_t initiate_key_setup(struct site *st)
+static bool_t initiate_key_setup(struct site *st,string_t reason)
 {
     if (st->state!=SITE_RUN) return False;
+    slog(st,LOG_SETUP_INIT,"initiating key exchange (%s)",reason);
     if (st->address) {
-       slog(st,LOG_SETUP_INIT,"initiating key exchange; resolving address");
+       slog(st,LOG_SETUP_INIT,"resolving peer address");
        return enter_state_resolve(st);
     } else if (st->peer_valid) {
-       slog(st,LOG_SETUP_INIT,"initiating key exchange using old "
-            "peer address");
+       slog(st,LOG_SETUP_INIT,"using old peer address");
        st->setup_peer=st->peer;
        return enter_state_sentmsg1(st);
     }
@@ -735,6 +756,18 @@ static void activate_new_key(struct site *st)
     enter_state_run(st);
 }
 
+static void delete_key(struct site *st, string_t reason, uint32_t loglevel)
+{
+    if (st->current_valid) {
+       slog(st,loglevel,"session closed (%s)",reason);
+
+       st->current_valid=False;
+       st->current_transform->delkey(st->current_transform->st);
+       st->current_key_timeout=0;
+       set_link_quality(st);
+    }
+}
+
 static void state_assert(struct site *st, bool_t ok)
 {
     if (!ok) fatal("state_assert\n");
@@ -744,14 +777,7 @@ static void enter_state_stop(struct site *st)
 {
     st->state=SITE_STOP;
     st->timeout=0;
-    st->current_transform->delkey(st->current_transform->st);
-    st->current_valid=False;
-    st->current_key_timeout=0;
-    
-    st->peer_valid=False;
-
-    set_link_quality(st);
-    
+    delete_key(st,"entering state STOP",LOG_TIMEOUT_KEY);
     st->new_transform->delkey(st->new_transform->st);
 }
 
@@ -769,7 +795,7 @@ static void set_link_quality(struct site *st)
     else
        quality=LINK_QUALITY_DOWN;
 
-    st->netlink->set_quality(st->netlink->st,st->netlink_cid,quality);
+    st->netlink->set_quality(st->netlink->st,quality);
 }
 
 static void enter_state_run(struct site *st)
@@ -886,6 +912,27 @@ static bool_t send_msg6(struct site *st)
     return False;
 }
 
+static bool_t send_msg7(struct site *st,string_t reason)
+{
+    string_t transform_err;
+
+    if (st->current_valid && st->peer_valid && st->buffer.free) {
+       BUF_ALLOC(&st->buffer,"site:MSG7");
+       buffer_init(&st->buffer,st->transform->max_start_pad+(4*3));
+       buf_append_uint32(&st->buffer,LABEL_MSG7);
+       buf_append_string(&st->buffer,reason);
+       st->current_transform->forwards(st->current_transform->st,
+                                       &st->buffer, &transform_err);
+       buf_prepend_uint32(&st->buffer,LABEL_MSG0);
+       buf_prepend_uint32(&st->buffer,(uint32_t)st);
+       buf_prepend_uint32(&st->buffer,st->remote_session_id);
+       st->comm->sendmsg(st->comm->st,&st->buffer,&st->peer);
+       BUF_FREE(&st->buffer);
+       return True;
+    }
+    return False;
+}
+
 /* We go into this state if our peer becomes uncommunicative. Similar to
    the "stop" state, we forget all session keys for a while, before
    re-entering the "run" state. */
@@ -942,18 +989,14 @@ static void site_afterpoll(void *sst, struct pollfd *fds, int nfds,
        }
     }
     if (st->current_key_timeout && *now>st->current_key_timeout) {
-       slog(st,LOG_TIMEOUT_KEY,"maximum key life exceeded; session closed");
-       st->current_valid=False;
-       st->current_transform->delkey(st->current_transform->st);
-       st->current_key_timeout=0;
-       set_link_quality(st);
+       delete_key(st,"maximum key life exceeded",LOG_TIMEOUT_KEY);
     }
 }
 
 /* This function is called by the netlink device to deliver packets
    intended for the remote network. The packet is in "raw" wire
    format, but is guaranteed to be word-aligned. */
-static void site_outgoing(void *sst, void *cid, struct buffer_if *buf)
+static void site_outgoing(void *sst, struct buffer_if *buf)
 {
     struct site *st=sst;
     string_t transform_err;
@@ -982,7 +1025,7 @@ static void site_outgoing(void *sst, void *cid, struct buffer_if *buf)
 
     slog(st,LOG_DROP,"discarding outgoing packet of size %d",buf->size);
     BUF_FREE(buf);
-    initiate_key_setup(st);
+    initiate_key_setup(st,"outgoing packet");
 }
 
 /* This function is called by the communication device to deliver
@@ -1044,10 +1087,19 @@ static bool_t site_incoming(void *sst, struct buffer_if *buf,
        return False; /* Not for us. */
     }
     if (dest==(uint32_t)st) {
-       uint32_t msgtype=ntohl(*(uint32_t *)(buf->start+8));
+       uint32_t msgtype=ntohl(get_uint32(buf->start+8));
        /* Explicitly addressed to us */
        if (msgtype!=LABEL_MSG0) dump_packet(st,buf,source,True);
        switch (msgtype) {
+       case 0: /* NAK */
+           /* If the source is our current peer then initiate a key setup,
+              because our peer's forgotten the key */
+           if (get_uint32(buf->start+4)==st->remote_session_id) {
+               initiate_key_setup(st,"received a NAK");
+           } else {
+               slog(st,LOG_SEC,"bad incoming NAK");
+           }
+           break;
        case LABEL_MSG0:
            process_msg0(st,buf,source);
            break;
@@ -1112,10 +1164,6 @@ static bool_t site_incoming(void *sst, struct buffer_if *buf,
                slog(st,LOG_SEC,"invalid MSG6");
            }
            break;
-       case LABEL_MSG8:
-           /* NAK packet: enter state where we ping and check for response */
-           slog(st,LOG_ERROR,"received a NAK");
-           break;
        default:
            slog(st,LOG_SEC,"received message of unknown type 0x%08x",
                 msgtype);
@@ -1135,13 +1183,20 @@ static void site_control(void *vst, bool_t run)
     else enter_state_stop(st);
 }
 
+static void site_phase_hook(void *sst, uint32_t newphase)
+{
+    struct site *st=sst;
+
+    /* The program is shutting down; tell our peer */
+    send_msg7(st,"shutting down");
+}
+
 static list_t *site_apply(closure_t *self, struct cloc loc, dict_t *context,
                          list_t *args)
 {
     struct site *st;
     item_t *item;
     dict_t *dict;
-    uint32_t netlink_options;
 
     st=safe_malloc(sizeof(*st),"site_apply");
 
@@ -1170,7 +1225,7 @@ static list_t *site_apply(closure_t *self, struct cloc loc, dict_t *context,
        free(st);
        return NULL;
     }
-    st->netlink=find_cl_if(dict,"netlink",CL_NETLINK,True,"site",loc);
+    st->netlink=find_cl_if(dict,"link",CL_NETLINK,True,"site",loc);
     st->comm=find_cl_if(dict,"comm",CL_COMM,True,"site",loc);
     st->resolver=find_cl_if(dict,"resolver",CL_RESOLVER,True,"site",loc);
     st->log=find_cl_if(dict,"log",CL_LOG,True,"site",loc);
@@ -1181,8 +1236,6 @@ static list_t *site_apply(closure_t *self, struct cloc loc, dict_t *context,
     if (st->address)
        st->remoteport=dict_read_number(dict,"port",True,"site",loc,0);
     else st->remoteport=0;
-    dict_read_subnet_list(dict, "networks", True, "site", loc,
-                         &st->remotenets);
     st->pubkey=find_cl_if(dict,"key",CL_RSAPUBKEY,True,"site",loc);
 
     st->transform=
@@ -1215,9 +1268,6 @@ static list_t *site_apply(closure_t *self, struct cloc loc, dict_t *context,
     st->log_events=string_list_to_word(dict_lookup(dict,"log-events"),
                                       log_event_table,"site");
 
-    netlink_options=string_list_to_word(dict_lookup(dict,"netlink-options"),
-                                       netlink_option_table,"site");
-
     st->tunname=safe_malloc(strlen(st->localname)+strlen(st->remotename)+5,
                            "site_apply");
     sprintf(st->tunname,"%s<->%s",st->localname,st->remotename);
@@ -1248,17 +1298,9 @@ static list_t *site_apply(closure_t *self, struct cloc loc, dict_t *context,
     st->sharedsecret=safe_malloc(st->transform->keylen,"site:sharedsecret");
 
     /* We need to register the remote networks with the netlink device */
-    st->netlink_cid=st->netlink->regnets(st->netlink->st, &st->remotenets,
-                                        site_outgoing, st,
-                                        st->transform->max_start_pad+(4*4),
-                                        st->transform->max_end_pad,
-                                        netlink_options, st->tunname);
-    if (!st->netlink_cid) {
-       Message(M_WARNING,"%s: netlink device did not let us register "
-               "our remote networks. This site will not start.\n",
-               st->tunname);
-       return NULL; /* XXX should free site first */
-    }
+    st->netlink->reg(st->netlink->st, site_outgoing, st,
+                    st->transform->max_start_pad+(4*4),
+                    st->transform->max_end_pad);
 
     st->comm->request_notify(st->comm->st, st, site_incoming);
 
@@ -1267,6 +1309,8 @@ static list_t *site_apply(closure_t *self, struct cloc loc, dict_t *context,
 
     enter_state_stop(st);
 
+    add_hook(PHASE_SHUTDOWN,site_phase_hook,st);
+
     return new_closure(&st->cl);
 }